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OpenCloudOS-Kernel/net/ipv4/tcp_timer.c

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Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
/*
* INET An implementation of the TCP/IP protocol suite for the LINUX
* operating system. INET is implemented using the BSD Socket
* interface as the means of communication with the user level.
*
* Implementation of the Transmission Control Protocol(TCP).
*
[PATCH] update Ross Biro bouncing email address Ross moved. Remove the bad email address so people will find the correct one in ./CREDITS. Signed-off-by: Jesper Juhl <juhl-lkml@dif.dk> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-05-06 07:16:16 +08:00
* Authors: Ross Biro
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
* Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
* Mark Evans, <evansmp@uhura.aston.ac.uk>
* Corey Minyard <wf-rch!minyard@relay.EU.net>
* Florian La Roche, <flla@stud.uni-sb.de>
* Charles Hedrick, <hedrick@klinzhai.rutgers.edu>
* Linus Torvalds, <torvalds@cs.helsinki.fi>
* Alan Cox, <gw4pts@gw4pts.ampr.org>
* Matthew Dillon, <dillon@apollo.west.oic.com>
* Arnt Gulbrandsen, <agulbra@nvg.unit.no>
* Jorge Cwik, <jorge@laser.satlink.net>
*/
#include <linux/module.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 16:04:11 +08:00
#include <linux/gfp.h>
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
#include <net/tcp.h>
tcp_timer.c: Add kernel-doc function descriptions This adds kernel-doc style descriptions for 6 functions and fixes 1 typo. Signed-off-by: Richard Sailer <richard@weltraumpflege.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-07-16 10:04:34 +08:00
/**
* tcp_write_err() - close socket and save error info
* @sk: The socket the error has appeared on.
*
* Returns: Nothing (void)
*/
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
static void tcp_write_err(struct sock *sk)
{
sk->sk_err = sk->sk_err_soft ? : ETIMEDOUT;
sk->sk_error_report(sk);
tcp_done(sk);
net: rename NET_{ADD|INC}_STATS_BH() Rename NET_INC_STATS_BH() to __NET_INC_STATS() and NET_ADD_STATS_BH() to __NET_ADD_STATS() Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-28 07:44:39 +08:00
__NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPABORTONTIMEOUT);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
}
tcp_timer.c: Add kernel-doc function descriptions This adds kernel-doc style descriptions for 6 functions and fixes 1 typo. Signed-off-by: Richard Sailer <richard@weltraumpflege.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-07-16 10:04:34 +08:00
/**
* tcp_out_of_resources() - Close socket if out of resources
* @sk: pointer to current socket
* @do_reset: send a last packet with reset flag
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
*
tcp_timer.c: Add kernel-doc function descriptions This adds kernel-doc style descriptions for 6 functions and fixes 1 typo. Signed-off-by: Richard Sailer <richard@weltraumpflege.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-07-16 10:04:34 +08:00
* Do not allow orphaned sockets to eat all our resources.
* This is direct violation of TCP specs, but it is required
* to prevent DoS attacks. It is called when a retransmission timeout
* or zero probe timeout occurs on orphaned socket.
*
net: tcp: close sock if net namespace is exiting When a tcp socket is closed, if it detects that its net namespace is exiting, close immediately and do not wait for FIN sequence. For normal sockets, a reference is taken to their net namespace, so it will never exit while the socket is open. However, kernel sockets do not take a reference to their net namespace, so it may begin exiting while the kernel socket is still open. In this case if the kernel socket is a tcp socket, it will stay open trying to complete its close sequence. The sock's dst(s) hold a reference to their interface, which are all transferred to the namespace's loopback interface when the real interfaces are taken down. When the namespace tries to take down its loopback interface, it hangs waiting for all references to the loopback interface to release, which results in messages like: unregister_netdevice: waiting for lo to become free. Usage count = 1 These messages continue until the socket finally times out and closes. Since the net namespace cleanup holds the net_mutex while calling its registered pernet callbacks, any new net namespace initialization is blocked until the current net namespace finishes exiting. After this change, the tcp socket notices the exiting net namespace, and closes immediately, releasing its dst(s) and their reference to the loopback interface, which lets the net namespace continue exiting. Link: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1711407 Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=97811 Signed-off-by: Dan Streetman <ddstreet@canonical.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-19 05:14:26 +08:00
* Also close if our net namespace is exiting; in that case there is no
* hope of ever communicating again since all netns interfaces are already
* down (or about to be down), and we need to release our dst references,
* which have been moved to the netns loopback interface, so the namespace
* can finish exiting. This condition is only possible if we are a kernel
* socket, as those do not hold references to the namespace.
*
tcp_timer.c: Add kernel-doc function descriptions This adds kernel-doc style descriptions for 6 functions and fixes 1 typo. Signed-off-by: Richard Sailer <richard@weltraumpflege.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-07-16 10:04:34 +08:00
* Criteria is still not confirmed experimentally and may change.
* We kill the socket, if:
* 1. If number of orphaned sockets exceeds an administratively configured
* limit.
* 2. If we have strong memory pressure.
net: tcp: close sock if net namespace is exiting When a tcp socket is closed, if it detects that its net namespace is exiting, close immediately and do not wait for FIN sequence. For normal sockets, a reference is taken to their net namespace, so it will never exit while the socket is open. However, kernel sockets do not take a reference to their net namespace, so it may begin exiting while the kernel socket is still open. In this case if the kernel socket is a tcp socket, it will stay open trying to complete its close sequence. The sock's dst(s) hold a reference to their interface, which are all transferred to the namespace's loopback interface when the real interfaces are taken down. When the namespace tries to take down its loopback interface, it hangs waiting for all references to the loopback interface to release, which results in messages like: unregister_netdevice: waiting for lo to become free. Usage count = 1 These messages continue until the socket finally times out and closes. Since the net namespace cleanup holds the net_mutex while calling its registered pernet callbacks, any new net namespace initialization is blocked until the current net namespace finishes exiting. After this change, the tcp socket notices the exiting net namespace, and closes immediately, releasing its dst(s) and their reference to the loopback interface, which lets the net namespace continue exiting. Link: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1711407 Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=97811 Signed-off-by: Dan Streetman <ddstreet@canonical.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-19 05:14:26 +08:00
* 3. If our net namespace is exiting.
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
*/
tcp: abort orphan sockets stalling on zero window probes Currently we have two different policies for orphan sockets that repeatedly stall on zero window ACKs. If a socket gets a zero window ACK when it is transmitting data, the RTO is used to probe the window. The socket is aborted after roughly tcp_orphan_retries() retries (as in tcp_write_timeout()). But if the socket was idle when it received the zero window ACK, and later wants to send more data, we use the probe timer to probe the window. If the receiver always returns zero window ACKs, icsk_probes keeps getting reset in tcp_ack() and the orphan socket can stall forever until the system reaches the orphan limit (as commented in tcp_probe_timer()). This opens up a simple attack to create lots of hanging orphan sockets to burn the memory and the CPU, as demonstrated in the recent netdev post "TCP connection will hang in FIN_WAIT1 after closing if zero window is advertised." http://www.spinics.net/lists/netdev/msg296539.html This patch follows the design in RTO-based probe: we abort an orphan socket stalling on zero window when the probe timer reaches both the maximum backoff and the maximum RTO. For example, an 100ms RTT connection will timeout after roughly 153 seconds (0.3 + 0.6 + .... + 76.8) if the receiver keeps the window shut. If the orphan socket passes this check, but the system already has too many orphans (as in tcp_out_of_resources()), we still abort it but we'll also send an RST packet as the connection may still be active. In addition, we change TCP_USER_TIMEOUT to cover (life or dead) sockets stalled on zero-window probes. This changes the semantics of TCP_USER_TIMEOUT slightly because it previously only applies when the socket has pending transmission. Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Reported-by: Andrey Dmitrov <andrey.dmitrov@oktetlabs.ru> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-30 04:20:38 +08:00
static int tcp_out_of_resources(struct sock *sk, bool do_reset)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
{
struct tcp_sock *tp = tcp_sk(sk);
tcp: Combat per-cpu skew in orphan tests. As reported by Anton Blanchard when we use percpu_counter_read_positive() to make our orphan socket limit checks, the check can be off by up to num_cpus_online() * batch (which is 32 by default) which on a 128 cpu machine can be as large as the default orphan limit itself. Fix this by doing the full expensive sum check if the optimized check triggers. Reported-by: Anton Blanchard <anton@samba.org> Signed-off-by: David S. Miller <davem@davemloft.net> Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
2010-08-25 17:27:49 +08:00
int shift = 0;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
[NET] IPV4: Fix whitespace errors. Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-02-09 22:24:47 +08:00
/* If peer does not open window for long time, or did not transmit
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
* anything for long time, penalize it. */
tcp: use tcp_jiffies32 to feed tp->lsndtime Use tcp_jiffies32 instead of tcp_time_stamp to feed tp->lsndtime. tcp_time_stamp will soon be a litle bit more expensive than simply reading 'jiffies'. Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-17 05:00:03 +08:00
if ((s32)(tcp_jiffies32 - tp->lsndtime) > 2*TCP_RTO_MAX || !do_reset)
tcp: Combat per-cpu skew in orphan tests. As reported by Anton Blanchard when we use percpu_counter_read_positive() to make our orphan socket limit checks, the check can be off by up to num_cpus_online() * batch (which is 32 by default) which on a 128 cpu machine can be as large as the default orphan limit itself. Fix this by doing the full expensive sum check if the optimized check triggers. Reported-by: Anton Blanchard <anton@samba.org> Signed-off-by: David S. Miller <davem@davemloft.net> Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
2010-08-25 17:27:49 +08:00
shift++;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
/* If some dubious ICMP arrived, penalize even more. */
if (sk->sk_err_soft)
tcp: Combat per-cpu skew in orphan tests. As reported by Anton Blanchard when we use percpu_counter_read_positive() to make our orphan socket limit checks, the check can be off by up to num_cpus_online() * batch (which is 32 by default) which on a 128 cpu machine can be as large as the default orphan limit itself. Fix this by doing the full expensive sum check if the optimized check triggers. Reported-by: Anton Blanchard <anton@samba.org> Signed-off-by: David S. Miller <davem@davemloft.net> Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
2010-08-25 17:27:49 +08:00
shift++;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
net: Disambiguate kernel message Some of our machines were reporting: TCP: too many of orphaned sockets even when the number of orphaned sockets was well below the limit. We print a different message depending on whether we're out of TCP memory or there are too many orphaned sockets. Also move the check out of line and cleanup the messages that were printed. Signed-off-by: Arun Sharma <asharma@fb.com> Suggested-by: Mohan Srinivasan <mohan@fb.com> Cc: netdev@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: David Miller <davem@davemloft.net> Cc: Glauber Costa <glommer@parallels.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Joe Perches <joe@perches.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-01-31 06:16:06 +08:00
if (tcp_check_oom(sk, shift)) {
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
/* Catch exceptional cases, when connection requires reset.
* 1. Last segment was sent recently. */
tcp: use tcp_jiffies32 to feed tp->lsndtime Use tcp_jiffies32 instead of tcp_time_stamp to feed tp->lsndtime. tcp_time_stamp will soon be a litle bit more expensive than simply reading 'jiffies'. Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-17 05:00:03 +08:00
if ((s32)(tcp_jiffies32 - tp->lsndtime) <= TCP_TIMEWAIT_LEN ||
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
/* 2. Window is closed. */
(!tp->snd_wnd && !tp->packets_out))
tcp: abort orphan sockets stalling on zero window probes Currently we have two different policies for orphan sockets that repeatedly stall on zero window ACKs. If a socket gets a zero window ACK when it is transmitting data, the RTO is used to probe the window. The socket is aborted after roughly tcp_orphan_retries() retries (as in tcp_write_timeout()). But if the socket was idle when it received the zero window ACK, and later wants to send more data, we use the probe timer to probe the window. If the receiver always returns zero window ACKs, icsk_probes keeps getting reset in tcp_ack() and the orphan socket can stall forever until the system reaches the orphan limit (as commented in tcp_probe_timer()). This opens up a simple attack to create lots of hanging orphan sockets to burn the memory and the CPU, as demonstrated in the recent netdev post "TCP connection will hang in FIN_WAIT1 after closing if zero window is advertised." http://www.spinics.net/lists/netdev/msg296539.html This patch follows the design in RTO-based probe: we abort an orphan socket stalling on zero window when the probe timer reaches both the maximum backoff and the maximum RTO. For example, an 100ms RTT connection will timeout after roughly 153 seconds (0.3 + 0.6 + .... + 76.8) if the receiver keeps the window shut. If the orphan socket passes this check, but the system already has too many orphans (as in tcp_out_of_resources()), we still abort it but we'll also send an RST packet as the connection may still be active. In addition, we change TCP_USER_TIMEOUT to cover (life or dead) sockets stalled on zero-window probes. This changes the semantics of TCP_USER_TIMEOUT slightly because it previously only applies when the socket has pending transmission. Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Reported-by: Andrey Dmitrov <andrey.dmitrov@oktetlabs.ru> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-30 04:20:38 +08:00
do_reset = true;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
if (do_reset)
tcp_send_active_reset(sk, GFP_ATOMIC);
tcp_done(sk);
net: rename NET_{ADD|INC}_STATS_BH() Rename NET_INC_STATS_BH() to __NET_INC_STATS() and NET_ADD_STATS_BH() to __NET_ADD_STATS() Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-28 07:44:39 +08:00
__NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPABORTONMEMORY);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
return 1;
}
net: tcp: close sock if net namespace is exiting When a tcp socket is closed, if it detects that its net namespace is exiting, close immediately and do not wait for FIN sequence. For normal sockets, a reference is taken to their net namespace, so it will never exit while the socket is open. However, kernel sockets do not take a reference to their net namespace, so it may begin exiting while the kernel socket is still open. In this case if the kernel socket is a tcp socket, it will stay open trying to complete its close sequence. The sock's dst(s) hold a reference to their interface, which are all transferred to the namespace's loopback interface when the real interfaces are taken down. When the namespace tries to take down its loopback interface, it hangs waiting for all references to the loopback interface to release, which results in messages like: unregister_netdevice: waiting for lo to become free. Usage count = 1 These messages continue until the socket finally times out and closes. Since the net namespace cleanup holds the net_mutex while calling its registered pernet callbacks, any new net namespace initialization is blocked until the current net namespace finishes exiting. After this change, the tcp socket notices the exiting net namespace, and closes immediately, releasing its dst(s) and their reference to the loopback interface, which lets the net namespace continue exiting. Link: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1711407 Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=97811 Signed-off-by: Dan Streetman <ddstreet@canonical.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-19 05:14:26 +08:00
if (!check_net(sock_net(sk))) {
/* Not possible to send reset; just close */
tcp_done(sk);
return 1;
}
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
return 0;
}
tcp_timer.c: Add kernel-doc function descriptions This adds kernel-doc style descriptions for 6 functions and fixes 1 typo. Signed-off-by: Richard Sailer <richard@weltraumpflege.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-07-16 10:04:34 +08:00
/**
* tcp_orphan_retries() - Returns maximal number of retries on an orphaned socket
* @sk: Pointer to the current socket.
* @alive: bool, socket alive state
*/
tcp: change type of alive from int to bool The alive parameter of tcp_orphan_retries, indicates whether the connection is assumed alive or not. In the function and all places calling it is used as a boolean value. Therefore this changes the type of alive to bool in the function definition and all calling locations. Since tcp_orphan_tries is a tcp_timer.c local function no change in any other file or header is necessary. Signed-off-by: Richard Sailer <richard@weltraumpflege.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-10-09 08:41:37 +08:00
static int tcp_orphan_retries(struct sock *sk, bool alive)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
{
ipv4: Namespaceify tcp_orphan_retries sysctl knob Signed-off-by: Nikolay Borisov <kernel@kyup.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-02-03 15:46:55 +08:00
int retries = sock_net(sk)->ipv4.sysctl_tcp_orphan_retries; /* May be zero. */
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
/* We know from an ICMP that something is wrong. */
if (sk->sk_err_soft && !alive)
retries = 0;
/* However, if socket sent something recently, select some safe
* number of retries. 8 corresponds to >100 seconds with minimal
* RTO of 200msec. */
if (retries == 0 && alive)
retries = 8;
return retries;
}
[TCP]: tcp_write_timeout.c cleanup Before submiting a patch to change a divide to a right shift, I felt necessary to create a helper function tcp_mtu_probing() to reduce length of lines exceeding 100 chars in tcp_write_timeout(). Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-12-21 17:50:43 +08:00
static void tcp_mtu_probing(struct inet_connection_sock *icsk, struct sock *sk)
{
tcp: tcp_mtu_probing() cleanup Reduce one indentation level to make code more readable. tcp_sync_mss() can be factorized. Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-03 21:09:17 +08:00
const struct net *net = sock_net(sk);
int mss;
ipv4: Namespecify TCP PMTU mechanism Packetization Layer Path MTU Discovery works separately beside Path MTU Discovery at IP level, different net namespace has various requirements on which one to chose, e.g., a virutalized container instance would require TCP PMTU to probe an usable effective mtu for underlying tunnel, while the host would employ classical ICMP based PMTU to function. Hence making TCP PMTU mechanism per net namespace to decouple two functionality. Furthermore the probe base MSS should also be configured separately for each namespace. Signed-off-by: Fan Du <fan.du@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-02-10 09:53:16 +08:00
[TCP]: tcp_write_timeout.c cleanup Before submiting a patch to change a divide to a right shift, I felt necessary to create a helper function tcp_mtu_probing() to reduce length of lines exceeding 100 chars in tcp_write_timeout(). Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-12-21 17:50:43 +08:00
/* Black hole detection */
tcp: tcp_mtu_probing() cleanup Reduce one indentation level to make code more readable. tcp_sync_mss() can be factorized. Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-03 21:09:17 +08:00
if (!net->ipv4.sysctl_tcp_mtu_probing)
return;
if (!icsk->icsk_mtup.enabled) {
icsk->icsk_mtup.enabled = 1;
icsk->icsk_mtup.probe_timestamp = tcp_jiffies32;
} else {
mss = tcp_mtu_to_mss(sk, icsk->icsk_mtup.search_low) >> 1;
mss = min(net->ipv4.sysctl_tcp_base_mss, mss);
mss = max(mss, 68 - tcp_sk(sk)->tcp_header_len);
icsk->icsk_mtup.search_low = tcp_mss_to_mtu(sk, mss);
[TCP]: tcp_write_timeout.c cleanup Before submiting a patch to change a divide to a right shift, I felt necessary to create a helper function tcp_mtu_probing() to reduce length of lines exceeding 100 chars in tcp_write_timeout(). Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-12-21 17:50:43 +08:00
}
tcp: tcp_mtu_probing() cleanup Reduce one indentation level to make code more readable. tcp_sync_mss() can be factorized. Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-03 21:09:17 +08:00
tcp_sync_mss(sk, icsk->icsk_pmtu_cookie);
[TCP]: tcp_write_timeout.c cleanup Before submiting a patch to change a divide to a right shift, I felt necessary to create a helper function tcp_mtu_probing() to reduce length of lines exceeding 100 chars in tcp_write_timeout(). Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-12-21 17:50:43 +08:00
}
tcp_timer.c: Add kernel-doc function descriptions This adds kernel-doc style descriptions for 6 functions and fixes 1 typo. Signed-off-by: Richard Sailer <richard@weltraumpflege.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-07-16 10:04:34 +08:00
/**
* retransmits_timed_out() - returns true if this connection has timed out
* @sk: The current socket
* @boundary: max number of retransmissions
* @timeout: A custom timeout value.
* If set to 0 the default timeout is calculated and used.
* Using TCP_RTO_MIN and the number of unsuccessful retransmits.
*
* The default "timeout" value this function can calculate and use
* is equivalent to the timeout of a TCP Connection
* after "boundary" unsuccessful, exponentially backed-off
tcp: fix TCP_SYNCNT flakes After the mentioned commit, some of our packetdrill tests became flaky. TCP_SYNCNT socket option can limit the number of SYN retransmits. retransmits_timed_out() has to compare times computations based on local_clock() while timers are based on jiffies. With NTP adjustments and roundings we can observe 999 ms delay for 1000 ms timers. We end up sending one extra SYN packet. Gimmick added in commit 6fa12c850314 ("Revert Backoff [v3]: Calculate TCP's connection close threshold as a time value") makes no real sense for TCP_SYN_SENT sockets where no RTO backoff can happen at all. Lets use a simpler logic for TCP_SYN_SENT sockets and remove @syn_set parameter from retransmits_timed_out() Fixes: 9a568de4818d ("tcp: switch TCP TS option (RFC 7323) to 1ms clock") Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-24 03:38:35 +08:00
* retransmissions with an initial RTO of TCP_RTO_MIN.
tcp: Stalling connections: Move timeout calculation routine This patch moves retransmits_timed_out() from include/net/tcp.h to tcp_timer.c, where it is used. Reported-by: Frederic Leroy <fredo@starox.org> Signed-off-by: Damian Lukowski <damian@tvk.rwth-aachen.de> Acked-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-12-07 14:06:16 +08:00
*/
static bool retransmits_timed_out(struct sock *sk,
tcp: Add TCP_USER_TIMEOUT socket option. This patch provides a "user timeout" support as described in RFC793. The socket option is also needed for the the local half of RFC5482 "TCP User Timeout Option". TCP_USER_TIMEOUT is a TCP level socket option that takes an unsigned int, when > 0, to specify the maximum amount of time in ms that transmitted data may remain unacknowledged before TCP will forcefully close the corresponding connection and return ETIMEDOUT to the application. If 0 is given, TCP will continue to use the system default. Increasing the user timeouts allows a TCP connection to survive extended periods without end-to-end connectivity. Decreasing the user timeouts allows applications to "fail fast" if so desired. Otherwise it may take upto 20 minutes with the current system defaults in a normal WAN environment. The socket option can be made during any state of a TCP connection, but is only effective during the synchronized states of a connection (ESTABLISHED, FIN-WAIT-1, FIN-WAIT-2, CLOSE-WAIT, CLOSING, or LAST-ACK). Moreover, when used with the TCP keepalive (SO_KEEPALIVE) option, TCP_USER_TIMEOUT will overtake keepalive to determine when to close a connection due to keepalive failure. The option does not change in anyway when TCP retransmits a packet, nor when a keepalive probe will be sent. This option, like many others, will be inherited by an acceptor from its listener. Signed-off-by: H.K. Jerry Chu <hkchu@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-28 03:13:28 +08:00
unsigned int boundary,
tcp: fix TCP_SYNCNT flakes After the mentioned commit, some of our packetdrill tests became flaky. TCP_SYNCNT socket option can limit the number of SYN retransmits. retransmits_timed_out() has to compare times computations based on local_clock() while timers are based on jiffies. With NTP adjustments and roundings we can observe 999 ms delay for 1000 ms timers. We end up sending one extra SYN packet. Gimmick added in commit 6fa12c850314 ("Revert Backoff [v3]: Calculate TCP's connection close threshold as a time value") makes no real sense for TCP_SYN_SENT sockets where no RTO backoff can happen at all. Lets use a simpler logic for TCP_SYN_SENT sockets and remove @syn_set parameter from retransmits_timed_out() Fixes: 9a568de4818d ("tcp: switch TCP TS option (RFC 7323) to 1ms clock") Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-24 03:38:35 +08:00
unsigned int timeout)
tcp: Stalling connections: Move timeout calculation routine This patch moves retransmits_timed_out() from include/net/tcp.h to tcp_timer.c, where it is used. Reported-by: Frederic Leroy <fredo@starox.org> Signed-off-by: Damian Lukowski <damian@tvk.rwth-aachen.de> Acked-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-12-07 14:06:16 +08:00
{
tcp: fix TCP_SYNCNT flakes After the mentioned commit, some of our packetdrill tests became flaky. TCP_SYNCNT socket option can limit the number of SYN retransmits. retransmits_timed_out() has to compare times computations based on local_clock() while timers are based on jiffies. With NTP adjustments and roundings we can observe 999 ms delay for 1000 ms timers. We end up sending one extra SYN packet. Gimmick added in commit 6fa12c850314 ("Revert Backoff [v3]: Calculate TCP's connection close threshold as a time value") makes no real sense for TCP_SYN_SENT sockets where no RTO backoff can happen at all. Lets use a simpler logic for TCP_SYN_SENT sockets and remove @syn_set parameter from retransmits_timed_out() Fixes: 9a568de4818d ("tcp: switch TCP TS option (RFC 7323) to 1ms clock") Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-24 03:38:35 +08:00
const unsigned int rto_base = TCP_RTO_MIN;
tcp: switch TCP TS option (RFC 7323) to 1ms clock TCP Timestamps option is defined in RFC 7323 Traditionally on linux, it has been tied to the internal 'jiffies' variable, because it had been a cheap and good enough generator. For TCP flows on the Internet, 1 ms resolution would be much better than 4ms or 10ms (HZ=250 or HZ=100 respectively) For TCP flows in the DC, Google has used usec resolution for more than two years with great success [1] Receive size autotuning (DRS) is indeed more precise and converges faster to optimal window size. This patch converts tp->tcp_mstamp to a plain u64 value storing a 1 usec TCP clock. This choice will allow us to upstream the 1 usec TS option as discussed in IETF 97. [1] https://www.ietf.org/proceedings/97/slides/slides-97-tcpm-tcp-options-for-low-latency-00.pdf Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-17 05:00:14 +08:00
unsigned int linear_backoff_thresh, start_ts;
tcp: Stalling connections: Move timeout calculation routine This patch moves retransmits_timed_out() from include/net/tcp.h to tcp_timer.c, where it is used. Reported-by: Frederic Leroy <fredo@starox.org> Signed-off-by: Damian Lukowski <damian@tvk.rwth-aachen.de> Acked-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-12-07 14:06:16 +08:00
if (!inet_csk(sk)->icsk_retransmits)
return false;
tcp: remove TCP_SKB_CB(skb)->when After commit 740b0f1841f6 ("tcp: switch rtt estimations to usec resolution"), we no longer need to maintain timestamps in two different fields. TCP_SKB_CB(skb)->when can be removed, as same information sits in skb_mstamp.stamp_jiffies Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-06 06:33:33 +08:00
start_ts = tcp_sk(sk)->retrans_stamp;
tcp: implement rb-tree based retransmit queue Using a linear list to store all skbs in write queue has been okay for quite a while : O(N) is not too bad when N < 500. Things get messy when N is the order of 100,000 : Modern TCP stacks want 10Gbit+ of throughput even with 200 ms RTT flows. 40 ns per cache line miss means a full scan can use 4 ms, blowing away CPU caches. SACK processing often can use various hints to avoid parsing whole retransmit queue. But with high packet losses and/or high reordering, hints no longer work. Sender has to process thousands of unfriendly SACK, accumulating a huge socket backlog, burning a cpu and massively dropping packets. Using an rb-tree for retransmit queue has been avoided for years because it added complexity and overhead, but now is the time to be more resistant and say no to quadratic behavior. 1) RTX queue is no longer part of the write queue : already sent skbs are stored in one rb-tree. 2) Since reaching the head of write queue no longer needs sk->sk_send_head, we added an union of sk_send_head and tcp_rtx_queue Tested: On receiver : netem on ingress : delay 150ms 200us loss 1 GRO disabled to force stress and SACK storms. for f in `seq 1 10` do ./netperf -H lpaa6 -l30 -- -K bbr -o THROUGHPUT|tail -1 done | awk '{print $0} {sum += $0} END {printf "%7u\n",sum}' Before patch : 323.87 351.48 339.59 338.62 306.72 204.07 304.93 291.88 202.47 176.88 2840 After patch: 1700.83 2207.98 2070.17 1544.26 2114.76 2124.89 1693.14 1080.91 2216.82 1299.94 18053 Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-06 13:21:27 +08:00
if (unlikely(!start_ts)) {
struct sk_buff *head = tcp_rtx_queue_head(sk);
if (!head)
return false;
start_ts = tcp_skb_timestamp(head);
}
tcp: Stalling connections: Move timeout calculation routine This patch moves retransmits_timed_out() from include/net/tcp.h to tcp_timer.c, where it is used. Reported-by: Frederic Leroy <fredo@starox.org> Signed-off-by: Damian Lukowski <damian@tvk.rwth-aachen.de> Acked-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-12-07 14:06:16 +08:00
tcp: Add TCP_USER_TIMEOUT socket option. This patch provides a "user timeout" support as described in RFC793. The socket option is also needed for the the local half of RFC5482 "TCP User Timeout Option". TCP_USER_TIMEOUT is a TCP level socket option that takes an unsigned int, when > 0, to specify the maximum amount of time in ms that transmitted data may remain unacknowledged before TCP will forcefully close the corresponding connection and return ETIMEDOUT to the application. If 0 is given, TCP will continue to use the system default. Increasing the user timeouts allows a TCP connection to survive extended periods without end-to-end connectivity. Decreasing the user timeouts allows applications to "fail fast" if so desired. Otherwise it may take upto 20 minutes with the current system defaults in a normal WAN environment. The socket option can be made during any state of a TCP connection, but is only effective during the synchronized states of a connection (ESTABLISHED, FIN-WAIT-1, FIN-WAIT-2, CLOSE-WAIT, CLOSING, or LAST-ACK). Moreover, when used with the TCP keepalive (SO_KEEPALIVE) option, TCP_USER_TIMEOUT will overtake keepalive to determine when to close a connection due to keepalive failure. The option does not change in anyway when TCP retransmits a packet, nor when a keepalive probe will be sent. This option, like many others, will be inherited by an acceptor from its listener. Signed-off-by: H.K. Jerry Chu <hkchu@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-28 03:13:28 +08:00
if (likely(timeout == 0)) {
Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 Conflicts: net/ipv4/Kconfig net/ipv4/tcp_timer.c
2010-10-05 02:56:38 +08:00
linear_backoff_thresh = ilog2(TCP_RTO_MAX/rto_base);
tcp: Stalling connections: Move timeout calculation routine This patch moves retransmits_timed_out() from include/net/tcp.h to tcp_timer.c, where it is used. Reported-by: Frederic Leroy <fredo@starox.org> Signed-off-by: Damian Lukowski <damian@tvk.rwth-aachen.de> Acked-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-12-07 14:06:16 +08:00
tcp: Add TCP_USER_TIMEOUT socket option. This patch provides a "user timeout" support as described in RFC793. The socket option is also needed for the the local half of RFC5482 "TCP User Timeout Option". TCP_USER_TIMEOUT is a TCP level socket option that takes an unsigned int, when > 0, to specify the maximum amount of time in ms that transmitted data may remain unacknowledged before TCP will forcefully close the corresponding connection and return ETIMEDOUT to the application. If 0 is given, TCP will continue to use the system default. Increasing the user timeouts allows a TCP connection to survive extended periods without end-to-end connectivity. Decreasing the user timeouts allows applications to "fail fast" if so desired. Otherwise it may take upto 20 minutes with the current system defaults in a normal WAN environment. The socket option can be made during any state of a TCP connection, but is only effective during the synchronized states of a connection (ESTABLISHED, FIN-WAIT-1, FIN-WAIT-2, CLOSE-WAIT, CLOSING, or LAST-ACK). Moreover, when used with the TCP keepalive (SO_KEEPALIVE) option, TCP_USER_TIMEOUT will overtake keepalive to determine when to close a connection due to keepalive failure. The option does not change in anyway when TCP retransmits a packet, nor when a keepalive probe will be sent. This option, like many others, will be inherited by an acceptor from its listener. Signed-off-by: H.K. Jerry Chu <hkchu@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-28 03:13:28 +08:00
if (boundary <= linear_backoff_thresh)
Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 Conflicts: net/ipv4/Kconfig net/ipv4/tcp_timer.c
2010-10-05 02:56:38 +08:00
timeout = ((2 << boundary) - 1) * rto_base;
tcp: Add TCP_USER_TIMEOUT socket option. This patch provides a "user timeout" support as described in RFC793. The socket option is also needed for the the local half of RFC5482 "TCP User Timeout Option". TCP_USER_TIMEOUT is a TCP level socket option that takes an unsigned int, when > 0, to specify the maximum amount of time in ms that transmitted data may remain unacknowledged before TCP will forcefully close the corresponding connection and return ETIMEDOUT to the application. If 0 is given, TCP will continue to use the system default. Increasing the user timeouts allows a TCP connection to survive extended periods without end-to-end connectivity. Decreasing the user timeouts allows applications to "fail fast" if so desired. Otherwise it may take upto 20 minutes with the current system defaults in a normal WAN environment. The socket option can be made during any state of a TCP connection, but is only effective during the synchronized states of a connection (ESTABLISHED, FIN-WAIT-1, FIN-WAIT-2, CLOSE-WAIT, CLOSING, or LAST-ACK). Moreover, when used with the TCP keepalive (SO_KEEPALIVE) option, TCP_USER_TIMEOUT will overtake keepalive to determine when to close a connection due to keepalive failure. The option does not change in anyway when TCP retransmits a packet, nor when a keepalive probe will be sent. This option, like many others, will be inherited by an acceptor from its listener. Signed-off-by: H.K. Jerry Chu <hkchu@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-28 03:13:28 +08:00
else
Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 Conflicts: net/ipv4/Kconfig net/ipv4/tcp_timer.c
2010-10-05 02:56:38 +08:00
timeout = ((2 << linear_backoff_thresh) - 1) * rto_base +
tcp: Add TCP_USER_TIMEOUT socket option. This patch provides a "user timeout" support as described in RFC793. The socket option is also needed for the the local half of RFC5482 "TCP User Timeout Option". TCP_USER_TIMEOUT is a TCP level socket option that takes an unsigned int, when > 0, to specify the maximum amount of time in ms that transmitted data may remain unacknowledged before TCP will forcefully close the corresponding connection and return ETIMEDOUT to the application. If 0 is given, TCP will continue to use the system default. Increasing the user timeouts allows a TCP connection to survive extended periods without end-to-end connectivity. Decreasing the user timeouts allows applications to "fail fast" if so desired. Otherwise it may take upto 20 minutes with the current system defaults in a normal WAN environment. The socket option can be made during any state of a TCP connection, but is only effective during the synchronized states of a connection (ESTABLISHED, FIN-WAIT-1, FIN-WAIT-2, CLOSE-WAIT, CLOSING, or LAST-ACK). Moreover, when used with the TCP keepalive (SO_KEEPALIVE) option, TCP_USER_TIMEOUT will overtake keepalive to determine when to close a connection due to keepalive failure. The option does not change in anyway when TCP retransmits a packet, nor when a keepalive probe will be sent. This option, like many others, will be inherited by an acceptor from its listener. Signed-off-by: H.K. Jerry Chu <hkchu@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-28 03:13:28 +08:00
(boundary - linear_backoff_thresh) * TCP_RTO_MAX;
}
tcp: switch TCP TS option (RFC 7323) to 1ms clock TCP Timestamps option is defined in RFC 7323 Traditionally on linux, it has been tied to the internal 'jiffies' variable, because it had been a cheap and good enough generator. For TCP flows on the Internet, 1 ms resolution would be much better than 4ms or 10ms (HZ=250 or HZ=100 respectively) For TCP flows in the DC, Google has used usec resolution for more than two years with great success [1] Receive size autotuning (DRS) is indeed more precise and converges faster to optimal window size. This patch converts tp->tcp_mstamp to a plain u64 value storing a 1 usec TCP clock. This choice will allow us to upstream the 1 usec TS option as discussed in IETF 97. [1] https://www.ietf.org/proceedings/97/slides/slides-97-tcpm-tcp-options-for-low-latency-00.pdf Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-17 05:00:14 +08:00
return (tcp_time_stamp(tcp_sk(sk)) - start_ts) >= jiffies_to_msecs(timeout);
tcp: Stalling connections: Move timeout calculation routine This patch moves retransmits_timed_out() from include/net/tcp.h to tcp_timer.c, where it is used. Reported-by: Frederic Leroy <fredo@starox.org> Signed-off-by: Damian Lukowski <damian@tvk.rwth-aachen.de> Acked-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-12-07 14:06:16 +08:00
}
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
/* A write timeout has occurred. Process the after effects. */
static int tcp_write_timeout(struct sock *sk)
{
[TCP]: MTU probing Implementation of packetization layer path mtu discovery for TCP, based on the internet-draft currently found at <http://www.ietf.org/internet-drafts/draft-ietf-pmtud-method-05.txt>. Signed-off-by: John Heffner <jheffner@psc.edu> Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-21 09:53:41 +08:00
struct inet_connection_sock *icsk = inet_csk(sk);
tcp: temporarily disable Fast Open on SYN timeout Fast Open currently has a fall back feature to address SYN-data being dropped but it requires the middle-box to pass on regular SYN retry after SYN-data. This is implemented in commit aab487435 ("net-tcp: Fast Open client - detecting SYN-data drops") However some NAT boxes will drop all subsequent packets after first SYN-data and blackholes the entire connections. An example is in commit 356d7d8 "netfilter: nf_conntrack: fix tcp_in_window for Fast Open". The sender should note such incidents and fall back to use the regular TCP handshake on subsequent attempts temporarily as well: after the second SYN timeouts the original Fast Open SYN is most likely lost. When such an event recurs Fast Open is disabled based on the number of recurrences exponentially. Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-30 01:09:05 +08:00
struct tcp_sock *tp = tcp_sk(sk);
ipv4: Namespaceify tcp syn retries sysctl knob Signed-off-by: Nikolay Borisov <kernel@kyup.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-02-03 15:46:49 +08:00
struct net *net = sock_net(sk);
tcp: fix TCP_SYNCNT flakes After the mentioned commit, some of our packetdrill tests became flaky. TCP_SYNCNT socket option can limit the number of SYN retransmits. retransmits_timed_out() has to compare times computations based on local_clock() while timers are based on jiffies. With NTP adjustments and roundings we can observe 999 ms delay for 1000 ms timers. We end up sending one extra SYN packet. Gimmick added in commit 6fa12c850314 ("Revert Backoff [v3]: Calculate TCP's connection close threshold as a time value") makes no real sense for TCP_SYN_SENT sockets where no RTO backoff can happen at all. Lets use a simpler logic for TCP_SYN_SENT sockets and remove @syn_set parameter from retransmits_timed_out() Fixes: 9a568de4818d ("tcp: switch TCP TS option (RFC 7323) to 1ms clock") Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-24 03:38:35 +08:00
bool expired, do_reset;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
int retry_until;
if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) {
tcp: temporarily disable Fast Open on SYN timeout Fast Open currently has a fall back feature to address SYN-data being dropped but it requires the middle-box to pass on regular SYN retry after SYN-data. This is implemented in commit aab487435 ("net-tcp: Fast Open client - detecting SYN-data drops") However some NAT boxes will drop all subsequent packets after first SYN-data and blackholes the entire connections. An example is in commit 356d7d8 "netfilter: nf_conntrack: fix tcp_in_window for Fast Open". The sender should note such incidents and fall back to use the regular TCP handshake on subsequent attempts temporarily as well: after the second SYN timeouts the original Fast Open SYN is most likely lost. When such an event recurs Fast Open is disabled based on the number of recurrences exponentially. Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-30 01:09:05 +08:00
if (icsk->icsk_retransmits) {
net: sk_dst_cache RCUification With latest CONFIG_PROVE_RCU stuff, I felt more comfortable to make this work. sk->sk_dst_cache is currently protected by a rwlock (sk_dst_lock) This rwlock is readlocked for a very small amount of time, and dst entries are already freed after RCU grace period. This calls for RCU again :) This patch converts sk_dst_lock to a spinlock, and use RCU for readers. __sk_dst_get() is supposed to be called with rcu_read_lock() or if socket locked by user, so use appropriate rcu_dereference_check() condition (rcu_read_lock_held() || sock_owned_by_user(sk)) This patch avoids two atomic ops per tx packet on UDP connected sockets, for example, and permits sk_dst_lock to be much less dirtied. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-04-09 07:03:29 +08:00
dst_negative_advice(sk);
tcp: Change txhash on every SYN and RTO retransmit The current code changes txhash (flowlables) on every retransmitted SYN/ACK, but only after the 2nd retransmitted SYN and only after tcp_retries1 RTO retransmits. With this patch: 1) txhash is changed with every SYN retransmits 2) txhash is changed with every RTO. The result is that we can start re-routing around failed (or very congested paths) as soon as possible. Otherwise application health checks may fail and the connection may be terminated before we start to change txhash. v4: Removed sysctl, txhash is changed for all RTOs v3: Removed text saying default value of sysctl is 0 (it is 100) v2: Added sysctl documentation and cleaned code Tested with packetdrill tests Signed-off-by: Lawrence Brakmo <brakmo@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-09-28 10:03:37 +08:00
} else if (!tp->syn_data && !tp->syn_fastopen) {
sk_rethink_txhash(sk);
tcp: temporarily disable Fast Open on SYN timeout Fast Open currently has a fall back feature to address SYN-data being dropped but it requires the middle-box to pass on regular SYN retry after SYN-data. This is implemented in commit aab487435 ("net-tcp: Fast Open client - detecting SYN-data drops") However some NAT boxes will drop all subsequent packets after first SYN-data and blackholes the entire connections. An example is in commit 356d7d8 "netfilter: nf_conntrack: fix tcp_in_window for Fast Open". The sender should note such incidents and fall back to use the regular TCP handshake on subsequent attempts temporarily as well: after the second SYN timeouts the original Fast Open SYN is most likely lost. When such an event recurs Fast Open is disabled based on the number of recurrences exponentially. Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-30 01:09:05 +08:00
}
ipv4: Namespaceify tcp syn retries sysctl knob Signed-off-by: Nikolay Borisov <kernel@kyup.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-02-03 15:46:49 +08:00
retry_until = icsk->icsk_syn_retries ? : net->ipv4.sysctl_tcp_syn_retries;
tcp: fix TCP_SYNCNT flakes After the mentioned commit, some of our packetdrill tests became flaky. TCP_SYNCNT socket option can limit the number of SYN retransmits. retransmits_timed_out() has to compare times computations based on local_clock() while timers are based on jiffies. With NTP adjustments and roundings we can observe 999 ms delay for 1000 ms timers. We end up sending one extra SYN packet. Gimmick added in commit 6fa12c850314 ("Revert Backoff [v3]: Calculate TCP's connection close threshold as a time value") makes no real sense for TCP_SYN_SENT sockets where no RTO backoff can happen at all. Lets use a simpler logic for TCP_SYN_SENT sockets and remove @syn_set parameter from retransmits_timed_out() Fixes: 9a568de4818d ("tcp: switch TCP TS option (RFC 7323) to 1ms clock") Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-24 03:38:35 +08:00
expired = icsk->icsk_retransmits >= retry_until;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
} else {
tcp: fix TCP_SYNCNT flakes After the mentioned commit, some of our packetdrill tests became flaky. TCP_SYNCNT socket option can limit the number of SYN retransmits. retransmits_timed_out() has to compare times computations based on local_clock() while timers are based on jiffies. With NTP adjustments and roundings we can observe 999 ms delay for 1000 ms timers. We end up sending one extra SYN packet. Gimmick added in commit 6fa12c850314 ("Revert Backoff [v3]: Calculate TCP's connection close threshold as a time value") makes no real sense for TCP_SYN_SENT sockets where no RTO backoff can happen at all. Lets use a simpler logic for TCP_SYN_SENT sockets and remove @syn_set parameter from retransmits_timed_out() Fixes: 9a568de4818d ("tcp: switch TCP TS option (RFC 7323) to 1ms clock") Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-24 03:38:35 +08:00
if (retransmits_timed_out(sk, net->ipv4.sysctl_tcp_retries1, 0)) {
[TCP]: MTU probing Implementation of packetization layer path mtu discovery for TCP, based on the internet-draft currently found at <http://www.ietf.org/internet-drafts/draft-ietf-pmtud-method-05.txt>. Signed-off-by: John Heffner <jheffner@psc.edu> Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-21 09:53:41 +08:00
/* Black hole detection */
[TCP]: tcp_write_timeout.c cleanup Before submiting a patch to change a divide to a right shift, I felt necessary to create a helper function tcp_mtu_probing() to reduce length of lines exceeding 100 chars in tcp_write_timeout(). Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-12-21 17:50:43 +08:00
tcp_mtu_probing(icsk, sk);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
net: sk_dst_cache RCUification With latest CONFIG_PROVE_RCU stuff, I felt more comfortable to make this work. sk->sk_dst_cache is currently protected by a rwlock (sk_dst_lock) This rwlock is readlocked for a very small amount of time, and dst entries are already freed after RCU grace period. This calls for RCU again :) This patch converts sk_dst_lock to a spinlock, and use RCU for readers. __sk_dst_get() is supposed to be called with rcu_read_lock() or if socket locked by user, so use appropriate rcu_dereference_check() condition (rcu_read_lock_held() || sock_owned_by_user(sk)) This patch avoids two atomic ops per tx packet on UDP connected sockets, for example, and permits sk_dst_lock to be much less dirtied. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-04-09 07:03:29 +08:00
dst_negative_advice(sk);
tcp: Change txhash on every SYN and RTO retransmit The current code changes txhash (flowlables) on every retransmitted SYN/ACK, but only after the 2nd retransmitted SYN and only after tcp_retries1 RTO retransmits. With this patch: 1) txhash is changed with every SYN retransmits 2) txhash is changed with every RTO. The result is that we can start re-routing around failed (or very congested paths) as soon as possible. Otherwise application health checks may fail and the connection may be terminated before we start to change txhash. v4: Removed sysctl, txhash is changed for all RTOs v3: Removed text saying default value of sysctl is 0 (it is 100) v2: Added sysctl documentation and cleaned code Tested with packetdrill tests Signed-off-by: Lawrence Brakmo <brakmo@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-09-28 10:03:37 +08:00
} else {
sk_rethink_txhash(sk);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
}
ipv4: Namespaceify tcp_retries2 sysctl knob Signed-off-by: Nikolay Borisov <kernel@kyup.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-02-03 15:46:54 +08:00
retry_until = net->ipv4.sysctl_tcp_retries2;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
if (sock_flag(sk, SOCK_DEAD)) {
tcp: change type of alive from int to bool The alive parameter of tcp_orphan_retries, indicates whether the connection is assumed alive or not. In the function and all places calling it is used as a boolean value. Therefore this changes the type of alive to bool in the function definition and all calling locations. Since tcp_orphan_tries is a tcp_timer.c local function no change in any other file or header is necessary. Signed-off-by: Richard Sailer <richard@weltraumpflege.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-10-09 08:41:37 +08:00
const bool alive = icsk->icsk_rto < TCP_RTO_MAX;
[NET] IPV4: Fix whitespace errors. Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-02-09 22:24:47 +08:00
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
retry_until = tcp_orphan_retries(sk, alive);
Revert Backoff [v3]: Calculate TCP's connection close threshold as a time value. RFC 1122 specifies two threshold values R1 and R2 for connection timeouts, which may represent a number of allowed retransmissions or a timeout value. Currently linux uses sysctl_tcp_retries{1,2} to specify the thresholds in number of allowed retransmissions. For any desired threshold R2 (by means of time) one can specify tcp_retries2 (by means of number of retransmissions) such that TCP will not time out earlier than R2. This is the case, because the RTO schedule follows a fixed pattern, namely exponential backoff. However, the RTO behaviour is not predictable any more if RTO backoffs can be reverted, as it is the case in the draft "Make TCP more Robust to Long Connectivity Disruptions" (http://tools.ietf.org/html/draft-zimmermann-tcp-lcd). In the worst case TCP would time out a connection after 3.2 seconds, if the initial RTO equaled MIN_RTO and each backoff has been reverted. This patch introduces a function retransmits_timed_out(N), which calculates the timeout of a TCP connection, assuming an initial RTO of MIN_RTO and N unsuccessful, exponentially backed-off retransmissions. Whenever timeout decisions are made by comparing the retransmission counter to some value N, this function can be used, instead. The meaning of tcp_retries2 will be changed, as many more RTO retransmissions can occur than the value indicates. However, it yields a timeout which is similar to the one of an unpatched, exponentially backing off TCP in the same scenario. As no application could rely on an RTO greater than MIN_RTO, there should be no risk of a regression. Signed-off-by: Damian Lukowski <damian@tvk.rwth-aachen.de> Acked-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-08-26 08:16:34 +08:00
do_reset = alive ||
tcp: fix TCP_SYNCNT flakes After the mentioned commit, some of our packetdrill tests became flaky. TCP_SYNCNT socket option can limit the number of SYN retransmits. retransmits_timed_out() has to compare times computations based on local_clock() while timers are based on jiffies. With NTP adjustments and roundings we can observe 999 ms delay for 1000 ms timers. We end up sending one extra SYN packet. Gimmick added in commit 6fa12c850314 ("Revert Backoff [v3]: Calculate TCP's connection close threshold as a time value") makes no real sense for TCP_SYN_SENT sockets where no RTO backoff can happen at all. Lets use a simpler logic for TCP_SYN_SENT sockets and remove @syn_set parameter from retransmits_timed_out() Fixes: 9a568de4818d ("tcp: switch TCP TS option (RFC 7323) to 1ms clock") Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-24 03:38:35 +08:00
!retransmits_timed_out(sk, retry_until, 0);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
Revert Backoff [v3]: Calculate TCP's connection close threshold as a time value. RFC 1122 specifies two threshold values R1 and R2 for connection timeouts, which may represent a number of allowed retransmissions or a timeout value. Currently linux uses sysctl_tcp_retries{1,2} to specify the thresholds in number of allowed retransmissions. For any desired threshold R2 (by means of time) one can specify tcp_retries2 (by means of number of retransmissions) such that TCP will not time out earlier than R2. This is the case, because the RTO schedule follows a fixed pattern, namely exponential backoff. However, the RTO behaviour is not predictable any more if RTO backoffs can be reverted, as it is the case in the draft "Make TCP more Robust to Long Connectivity Disruptions" (http://tools.ietf.org/html/draft-zimmermann-tcp-lcd). In the worst case TCP would time out a connection after 3.2 seconds, if the initial RTO equaled MIN_RTO and each backoff has been reverted. This patch introduces a function retransmits_timed_out(N), which calculates the timeout of a TCP connection, assuming an initial RTO of MIN_RTO and N unsuccessful, exponentially backed-off retransmissions. Whenever timeout decisions are made by comparing the retransmission counter to some value N, this function can be used, instead. The meaning of tcp_retries2 will be changed, as many more RTO retransmissions can occur than the value indicates. However, it yields a timeout which is similar to the one of an unpatched, exponentially backing off TCP in the same scenario. As no application could rely on an RTO greater than MIN_RTO, there should be no risk of a regression. Signed-off-by: Damian Lukowski <damian@tvk.rwth-aachen.de> Acked-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-08-26 08:16:34 +08:00
if (tcp_out_of_resources(sk, do_reset))
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
return 1;
}
tcp: fix TCP_SYNCNT flakes After the mentioned commit, some of our packetdrill tests became flaky. TCP_SYNCNT socket option can limit the number of SYN retransmits. retransmits_timed_out() has to compare times computations based on local_clock() while timers are based on jiffies. With NTP adjustments and roundings we can observe 999 ms delay for 1000 ms timers. We end up sending one extra SYN packet. Gimmick added in commit 6fa12c850314 ("Revert Backoff [v3]: Calculate TCP's connection close threshold as a time value") makes no real sense for TCP_SYN_SENT sockets where no RTO backoff can happen at all. Lets use a simpler logic for TCP_SYN_SENT sockets and remove @syn_set parameter from retransmits_timed_out() Fixes: 9a568de4818d ("tcp: switch TCP TS option (RFC 7323) to 1ms clock") Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-24 03:38:35 +08:00
expired = retransmits_timed_out(sk, retry_until,
icsk->icsk_user_timeout);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
}
tcp: pause Fast Open globally after third consecutive timeout Prior to this patch, active Fast Open is paused on a specific destination IP address if the previous connections to the IP address have experienced recurring timeouts . But recent experiments by Microsoft (https://goo.gl/cykmn7) and Mozilla browsers indicate the isssue is often caused by broken middle-boxes sitting close to the client. Therefore it is much better user experience if Fast Open is disabled out-right globally to avoid experiencing further timeouts on connections toward other destinations. This patch changes the destination-IP disablement to global disablement if a connection experiencing recurring timeouts or aborts due to timeout. Repeated incidents would still exponentially increase the pause time, starting from an hour. This is extremely conservative but an unfortunate compromise to minimize bad experience due to broken middle-boxes. Reported-by: Dragana Damjanovic <ddamjanovic@mozilla.com> Reported-by: Patrick McManus <mcmanus@ducksong.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Reviewed-by: Wei Wang <weiwan@google.com> Reviewed-by: Neal Cardwell <ncardwell@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-12-13 05:10:40 +08:00
tcp_fastopen_active_detect_blackhole(sk, expired);
bpf: Add sock_ops RTO callback Adds an optional call to sock_ops BPF program based on whether the BPF_SOCK_OPS_RTO_CB_FLAG is set in bpf_sock_ops_flags. The BPF program is passed 2 arguments: icsk_retransmits and whether the RTO has expired. Signed-off-by: Lawrence Brakmo <brakmo@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-01-26 08:14:11 +08:00
if (BPF_SOCK_OPS_TEST_FLAG(tp, BPF_SOCK_OPS_RTO_CB_FLAG))
tcp_call_bpf_3arg(sk, BPF_SOCK_OPS_RTO_CB,
icsk->icsk_retransmits,
icsk->icsk_rto, (int)expired);
tcp: fix TCP_SYNCNT flakes After the mentioned commit, some of our packetdrill tests became flaky. TCP_SYNCNT socket option can limit the number of SYN retransmits. retransmits_timed_out() has to compare times computations based on local_clock() while timers are based on jiffies. With NTP adjustments and roundings we can observe 999 ms delay for 1000 ms timers. We end up sending one extra SYN packet. Gimmick added in commit 6fa12c850314 ("Revert Backoff [v3]: Calculate TCP's connection close threshold as a time value") makes no real sense for TCP_SYN_SENT sockets where no RTO backoff can happen at all. Lets use a simpler logic for TCP_SYN_SENT sockets and remove @syn_set parameter from retransmits_timed_out() Fixes: 9a568de4818d ("tcp: switch TCP TS option (RFC 7323) to 1ms clock") Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-24 03:38:35 +08:00
if (expired) {
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
/* Has it gone just too far? */
tcp_write_err(sk);
return 1;
}
bpf: Add sock_ops RTO callback Adds an optional call to sock_ops BPF program based on whether the BPF_SOCK_OPS_RTO_CB_FLAG is set in bpf_sock_ops_flags. The BPF program is passed 2 arguments: icsk_retransmits and whether the RTO has expired. Signed-off-by: Lawrence Brakmo <brakmo@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-01-26 08:14:11 +08:00
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
return 0;
}
tcp: do not assume TCP code is non preemptible We want to to make TCP stack preemptible, as draining prequeue and backlog queues can take lot of time. Many SNMP updates were assuming that BH (and preemption) was disabled. Need to convert some __NET_INC_STATS() calls to NET_INC_STATS() and some __TCP_INC_STATS() to TCP_INC_STATS() Before using this_cpu_ptr(net->ipv4.tcp_sk) in tcp_v4_send_reset() and tcp_v4_send_ack(), we add an explicit preempt disabled section. Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-30 05:16:47 +08:00
/* Called with BH disabled */
tcp: improve latencies of timer triggered events Modern TCP stack highly depends on tcp_write_timer() having a small latency, but current implementation doesn't exactly meet the expectations. When a timer fires but finds the socket is owned by the user, it rearms itself for an additional delay hoping next run will be more successful. tcp_write_timer() for example uses a 50ms delay for next try, and it defeats many attempts to get predictable TCP behavior in term of latencies. Use the recently introduced tcp_release_cb(), so that the user owning the socket will call various handlers right before socket release. This will permit us to post a followup patch to address the tcp_tso_should_defer() syndrome (some deferred packets have to wait RTO timer to be transmitted, while cwnd should allow us to send them sooner) Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Tom Herbert <therbert@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Nandita Dukkipati <nanditad@google.com> Cc: H.K. Jerry Chu <hkchu@google.com> Cc: John Heffner <johnwheffner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-07-20 13:45:50 +08:00
void tcp_delack_timer_handler(struct sock *sk)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
{
[NET]: Introduce inet_connection_sock This creates struct inet_connection_sock, moving members out of struct tcp_sock that are shareable with other INET connection oriented protocols, such as DCCP, that in my private tree already uses most of these members. The functions that operate on these members were renamed, using a inet_csk_ prefix while not being moved yet to a new file, so as to ease the review of these changes. Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-10 11:10:42 +08:00
struct inet_connection_sock *icsk = inet_csk(sk);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
[TCP]: Do not purge sk_forward_alloc entirely in tcp_delack_timer(). Otherwise we beat heavily on the global tcp_memory atomics when all of the sockets in the system are slowly sending perioding packet clumps. Noticed and suggested by Eric Dumazet. Signed-off-by: David S. Miller <davem@davemloft.net>
2008-01-11 13:56:38 +08:00
sk_mem_reclaim_partial(sk);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
tcp: fix various issues for sockets morphing to listen state Dmitry Vyukov reported a divide by 0 triggered by syzkaller, exploiting tcp_disconnect() path that was never really considered and/or used before syzkaller ;) I was not able to reproduce the bug, but it seems issues here are the three possible actions that assumed they would never trigger on a listener. 1) tcp_write_timer_handler 2) tcp_delack_timer_handler 3) MTU reduction Only IPv6 MTU reduction was properly testing TCP_CLOSE and TCP_LISTEN states from tcp_v6_mtu_reduced() Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-03-04 06:08:21 +08:00
if (((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)) ||
!(icsk->icsk_ack.pending & ICSK_ACK_TIMER))
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
goto out;
[NET]: Introduce inet_connection_sock This creates struct inet_connection_sock, moving members out of struct tcp_sock that are shareable with other INET connection oriented protocols, such as DCCP, that in my private tree already uses most of these members. The functions that operate on these members were renamed, using a inet_csk_ prefix while not being moved yet to a new file, so as to ease the review of these changes. Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-10 11:10:42 +08:00
if (time_after(icsk->icsk_ack.timeout, jiffies)) {
sk_reset_timer(sk, &icsk->icsk_delack_timer, icsk->icsk_ack.timeout);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
goto out;
}
[NET]: Introduce inet_connection_sock This creates struct inet_connection_sock, moving members out of struct tcp_sock that are shareable with other INET connection oriented protocols, such as DCCP, that in my private tree already uses most of these members. The functions that operate on these members were renamed, using a inet_csk_ prefix while not being moved yet to a new file, so as to ease the review of these changes. Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-10 11:10:42 +08:00
icsk->icsk_ack.pending &= ~ICSK_ACK_TIMER;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
[NET]: Introduce inet_connection_sock This creates struct inet_connection_sock, moving members out of struct tcp_sock that are shareable with other INET connection oriented protocols, such as DCCP, that in my private tree already uses most of these members. The functions that operate on these members were renamed, using a inet_csk_ prefix while not being moved yet to a new file, so as to ease the review of these changes. Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-10 11:10:42 +08:00
if (inet_csk_ack_scheduled(sk)) {
if (!icsk->icsk_ack.pingpong) {
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
/* Delayed ACK missed: inflate ATO. */
[NET]: Introduce inet_connection_sock This creates struct inet_connection_sock, moving members out of struct tcp_sock that are shareable with other INET connection oriented protocols, such as DCCP, that in my private tree already uses most of these members. The functions that operate on these members were renamed, using a inet_csk_ prefix while not being moved yet to a new file, so as to ease the review of these changes. Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-10 11:10:42 +08:00
icsk->icsk_ack.ato = min(icsk->icsk_ack.ato << 1, icsk->icsk_rto);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
} else {
/* Delayed ACK missed: leave pingpong mode and
* deflate ATO.
*/
[NET]: Introduce inet_connection_sock This creates struct inet_connection_sock, moving members out of struct tcp_sock that are shareable with other INET connection oriented protocols, such as DCCP, that in my private tree already uses most of these members. The functions that operate on these members were renamed, using a inet_csk_ prefix while not being moved yet to a new file, so as to ease the review of these changes. Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-10 11:10:42 +08:00
icsk->icsk_ack.pingpong = 0;
icsk->icsk_ack.ato = TCP_ATO_MIN;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
}
tcp: refresh tcp_mstamp from timers callbacks Only the retransmit timer currently refreshes tcp_mstamp We should do the same for delayed acks and keepalives. Even if RFC 7323 does not request it, this is consistent to what linux did in the past, when TS values were based on jiffies. Fixes: 385e20706fac ("tcp: use tp->tcp_mstamp in output path") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Soheil Hassas Yeganeh <soheil@google.com> Cc: Mike Maloney <maloney@google.com> Cc: Neal Cardwell <ncardwell@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Acked-by: Mike Maloney <maloney@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-12-13 10:22:52 +08:00
tcp_mstamp_refresh(tcp_sk(sk));
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
tcp_send_ack(sk);
net: rename NET_{ADD|INC}_STATS_BH() Rename NET_INC_STATS_BH() to __NET_INC_STATS() and NET_ADD_STATS_BH() to __NET_ADD_STATS() Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-28 07:44:39 +08:00
__NET_INC_STATS(sock_net(sk), LINUX_MIB_DELAYEDACKS);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
}
out:
tcp: introduce tcp_under_memory_pressure() Introduce an optimized version of sk_under_memory_pressure() for TCP. Our intent is to use it in fast paths. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-05-16 03:39:27 +08:00
if (tcp_under_memory_pressure(sk))
[NET] CORE: Introducing new memory accounting interface. This patch introduces new memory accounting functions for each network protocol. Most of them are renamed from memory accounting functions for stream protocols. At the same time, some stream memory accounting functions are removed since other functions do same thing. Renaming: sk_stream_free_skb() -> sk_wmem_free_skb() __sk_stream_mem_reclaim() -> __sk_mem_reclaim() sk_stream_mem_reclaim() -> sk_mem_reclaim() sk_stream_mem_schedule -> __sk_mem_schedule() sk_stream_pages() -> sk_mem_pages() sk_stream_rmem_schedule() -> sk_rmem_schedule() sk_stream_wmem_schedule() -> sk_wmem_schedule() sk_charge_skb() -> sk_mem_charge() Removeing sk_stream_rfree(): consolidates into sock_rfree() sk_stream_set_owner_r(): consolidates into skb_set_owner_r() sk_stream_mem_schedule() The following functions are added. sk_has_account(): check if the protocol supports accounting sk_mem_uncharge(): do the opposite of sk_mem_charge() In addition, to achieve consolidation, updating sk_wmem_queued is removed from sk_mem_charge(). Next, to consolidate memory accounting functions, this patch adds memory accounting calls to network core functions. Moreover, present memory accounting call is renamed to new accounting call. Finally we replace present memory accounting calls with new interface in TCP and SCTP. Signed-off-by: Takahiro Yasui <tyasui@redhat.com> Signed-off-by: Hideo Aoki <haoki@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-12-31 16:11:19 +08:00
sk_mem_reclaim(sk);
tcp: improve latencies of timer triggered events Modern TCP stack highly depends on tcp_write_timer() having a small latency, but current implementation doesn't exactly meet the expectations. When a timer fires but finds the socket is owned by the user, it rearms itself for an additional delay hoping next run will be more successful. tcp_write_timer() for example uses a 50ms delay for next try, and it defeats many attempts to get predictable TCP behavior in term of latencies. Use the recently introduced tcp_release_cb(), so that the user owning the socket will call various handlers right before socket release. This will permit us to post a followup patch to address the tcp_tso_should_defer() syndrome (some deferred packets have to wait RTO timer to be transmitted, while cwnd should allow us to send them sooner) Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Tom Herbert <therbert@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Nandita Dukkipati <nanditad@google.com> Cc: H.K. Jerry Chu <hkchu@google.com> Cc: John Heffner <johnwheffner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-07-20 13:45:50 +08:00
}
tcp_timer.c: Add kernel-doc function descriptions This adds kernel-doc style descriptions for 6 functions and fixes 1 typo. Signed-off-by: Richard Sailer <richard@weltraumpflege.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-07-16 10:04:34 +08:00
/**
* tcp_delack_timer() - The TCP delayed ACK timeout handler
* @data: Pointer to the current socket. (gets casted to struct sock *)
*
* This function gets (indirectly) called when the kernel timer for a TCP packet
* of this socket expires. Calls tcp_delack_timer_handler() to do the actual work.
*
* Returns: Nothing (void)
*/
inet/connection_sock: Convert timers to use timer_setup() In preparation for unconditionally passing the struct timer_list pointer to all timer callbacks, switch to using the new timer_setup() and from_timer() to pass the timer pointer explicitly. Cc: "David S. Miller" <davem@davemloft.net> Cc: Gerrit Renker <gerrit@erg.abdn.ac.uk> Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org> Cc: netdev@vger.kernel.org Cc: dccp@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-17 08:29:19 +08:00
static void tcp_delack_timer(struct timer_list *t)
tcp: improve latencies of timer triggered events Modern TCP stack highly depends on tcp_write_timer() having a small latency, but current implementation doesn't exactly meet the expectations. When a timer fires but finds the socket is owned by the user, it rearms itself for an additional delay hoping next run will be more successful. tcp_write_timer() for example uses a 50ms delay for next try, and it defeats many attempts to get predictable TCP behavior in term of latencies. Use the recently introduced tcp_release_cb(), so that the user owning the socket will call various handlers right before socket release. This will permit us to post a followup patch to address the tcp_tso_should_defer() syndrome (some deferred packets have to wait RTO timer to be transmitted, while cwnd should allow us to send them sooner) Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Tom Herbert <therbert@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Nandita Dukkipati <nanditad@google.com> Cc: H.K. Jerry Chu <hkchu@google.com> Cc: John Heffner <johnwheffner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-07-20 13:45:50 +08:00
{
inet/connection_sock: Convert timers to use timer_setup() In preparation for unconditionally passing the struct timer_list pointer to all timer callbacks, switch to using the new timer_setup() and from_timer() to pass the timer pointer explicitly. Cc: "David S. Miller" <davem@davemloft.net> Cc: Gerrit Renker <gerrit@erg.abdn.ac.uk> Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org> Cc: netdev@vger.kernel.org Cc: dccp@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-17 08:29:19 +08:00
struct inet_connection_sock *icsk =
from_timer(icsk, t, icsk_delack_timer);
struct sock *sk = &icsk->icsk_inet.sk;
tcp: improve latencies of timer triggered events Modern TCP stack highly depends on tcp_write_timer() having a small latency, but current implementation doesn't exactly meet the expectations. When a timer fires but finds the socket is owned by the user, it rearms itself for an additional delay hoping next run will be more successful. tcp_write_timer() for example uses a 50ms delay for next try, and it defeats many attempts to get predictable TCP behavior in term of latencies. Use the recently introduced tcp_release_cb(), so that the user owning the socket will call various handlers right before socket release. This will permit us to post a followup patch to address the tcp_tso_should_defer() syndrome (some deferred packets have to wait RTO timer to be transmitted, while cwnd should allow us to send them sooner) Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Tom Herbert <therbert@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Nandita Dukkipati <nanditad@google.com> Cc: H.K. Jerry Chu <hkchu@google.com> Cc: John Heffner <johnwheffner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-07-20 13:45:50 +08:00
bh_lock_sock(sk);
if (!sock_owned_by_user(sk)) {
tcp_delack_timer_handler(sk);
} else {
inet/connection_sock: Convert timers to use timer_setup() In preparation for unconditionally passing the struct timer_list pointer to all timer callbacks, switch to using the new timer_setup() and from_timer() to pass the timer pointer explicitly. Cc: "David S. Miller" <davem@davemloft.net> Cc: Gerrit Renker <gerrit@erg.abdn.ac.uk> Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org> Cc: netdev@vger.kernel.org Cc: dccp@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-17 08:29:19 +08:00
icsk->icsk_ack.blocked = 1;
net: rename NET_{ADD|INC}_STATS_BH() Rename NET_INC_STATS_BH() to __NET_INC_STATS() and NET_ADD_STATS_BH() to __NET_ADD_STATS() Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-28 07:44:39 +08:00
__NET_INC_STATS(sock_net(sk), LINUX_MIB_DELAYEDACKLOCKED);
tcp: improve latencies of timer triggered events Modern TCP stack highly depends on tcp_write_timer() having a small latency, but current implementation doesn't exactly meet the expectations. When a timer fires but finds the socket is owned by the user, it rearms itself for an additional delay hoping next run will be more successful. tcp_write_timer() for example uses a 50ms delay for next try, and it defeats many attempts to get predictable TCP behavior in term of latencies. Use the recently introduced tcp_release_cb(), so that the user owning the socket will call various handlers right before socket release. This will permit us to post a followup patch to address the tcp_tso_should_defer() syndrome (some deferred packets have to wait RTO timer to be transmitted, while cwnd should allow us to send them sooner) Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Tom Herbert <therbert@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Nandita Dukkipati <nanditad@google.com> Cc: H.K. Jerry Chu <hkchu@google.com> Cc: John Heffner <johnwheffner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-07-20 13:45:50 +08:00
/* deleguate our work to tcp_release_cb() */
tcp: tsq: move tsq_flags close to sk_wmem_alloc tsq_flags being in the same cache line than sk_wmem_alloc makes a lot of sense. Both fields are changed from tcp_wfree() and more generally by various TSQ related functions. Prior patch made room in struct sock and added sk_tsq_flags, this patch deletes tsq_flags from struct tcp_sock. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-12-04 03:14:57 +08:00
if (!test_and_set_bit(TCP_DELACK_TIMER_DEFERRED, &sk->sk_tsq_flags))
tcp: fix possible socket refcount problem Commit 6f458dfb40 (tcp: improve latencies of timer triggered events) added bug leading to following trace : [ 2866.131281] IPv4: Attempt to release TCP socket in state 1 ffff880019ec0000 [ 2866.131726] [ 2866.132188] ========================= [ 2866.132281] [ BUG: held lock freed! ] [ 2866.132281] 3.6.0-rc1+ #622 Not tainted [ 2866.132281] ------------------------- [ 2866.132281] kworker/0:1/652 is freeing memory ffff880019ec0000-ffff880019ec0a1f, with a lock still held there! [ 2866.132281] (sk_lock-AF_INET-RPC){+.+...}, at: [<ffffffff81903619>] tcp_sendmsg+0x29/0xcc6 [ 2866.132281] 4 locks held by kworker/0:1/652: [ 2866.132281] #0: (rpciod){.+.+.+}, at: [<ffffffff81083567>] process_one_work+0x1de/0x47f [ 2866.132281] #1: ((&task->u.tk_work)){+.+.+.}, at: [<ffffffff81083567>] process_one_work+0x1de/0x47f [ 2866.132281] #2: (sk_lock-AF_INET-RPC){+.+...}, at: [<ffffffff81903619>] tcp_sendmsg+0x29/0xcc6 [ 2866.132281] #3: (&icsk->icsk_retransmit_timer){+.-...}, at: [<ffffffff81078017>] run_timer_softirq+0x1ad/0x35f [ 2866.132281] [ 2866.132281] stack backtrace: [ 2866.132281] Pid: 652, comm: kworker/0:1 Not tainted 3.6.0-rc1+ #622 [ 2866.132281] Call Trace: [ 2866.132281] <IRQ> [<ffffffff810bc527>] debug_check_no_locks_freed+0x112/0x159 [ 2866.132281] [<ffffffff818a0839>] ? __sk_free+0xfd/0x114 [ 2866.132281] [<ffffffff811549fa>] kmem_cache_free+0x6b/0x13a [ 2866.132281] [<ffffffff818a0839>] __sk_free+0xfd/0x114 [ 2866.132281] [<ffffffff818a08c0>] sk_free+0x1c/0x1e [ 2866.132281] [<ffffffff81911e1c>] tcp_write_timer+0x51/0x56 [ 2866.132281] [<ffffffff81078082>] run_timer_softirq+0x218/0x35f [ 2866.132281] [<ffffffff81078017>] ? run_timer_softirq+0x1ad/0x35f [ 2866.132281] [<ffffffff810f5831>] ? rb_commit+0x58/0x85 [ 2866.132281] [<ffffffff81911dcb>] ? tcp_write_timer_handler+0x148/0x148 [ 2866.132281] [<ffffffff81070bd6>] __do_softirq+0xcb/0x1f9 [ 2866.132281] [<ffffffff81a0a00c>] ? _raw_spin_unlock+0x29/0x2e [ 2866.132281] [<ffffffff81a1227c>] call_softirq+0x1c/0x30 [ 2866.132281] [<ffffffff81039f38>] do_softirq+0x4a/0xa6 [ 2866.132281] [<ffffffff81070f2b>] irq_exit+0x51/0xad [ 2866.132281] [<ffffffff81a129cd>] do_IRQ+0x9d/0xb4 [ 2866.132281] [<ffffffff81a0a3ef>] common_interrupt+0x6f/0x6f [ 2866.132281] <EOI> [<ffffffff8109d006>] ? sched_clock_cpu+0x58/0xd1 [ 2866.132281] [<ffffffff81a0a172>] ? _raw_spin_unlock_irqrestore+0x4c/0x56 [ 2866.132281] [<ffffffff81078692>] mod_timer+0x178/0x1a9 [ 2866.132281] [<ffffffff818a00aa>] sk_reset_timer+0x19/0x26 [ 2866.132281] [<ffffffff8190b2cc>] tcp_rearm_rto+0x99/0xa4 [ 2866.132281] [<ffffffff8190dfba>] tcp_event_new_data_sent+0x6e/0x70 [ 2866.132281] [<ffffffff8190f7ea>] tcp_write_xmit+0x7de/0x8e4 [ 2866.132281] [<ffffffff818a565d>] ? __alloc_skb+0xa0/0x1a1 [ 2866.132281] [<ffffffff8190f952>] __tcp_push_pending_frames+0x2e/0x8a [ 2866.132281] [<ffffffff81904122>] tcp_sendmsg+0xb32/0xcc6 [ 2866.132281] [<ffffffff819229c2>] inet_sendmsg+0xaa/0xd5 [ 2866.132281] [<ffffffff81922918>] ? inet_autobind+0x5f/0x5f [ 2866.132281] [<ffffffff810ee7f1>] ? trace_clock_local+0x9/0xb [ 2866.132281] [<ffffffff8189adab>] sock_sendmsg+0xa3/0xc4 [ 2866.132281] [<ffffffff810f5de6>] ? rb_reserve_next_event+0x26f/0x2d5 [ 2866.132281] [<ffffffff8103e6a9>] ? native_sched_clock+0x29/0x6f [ 2866.132281] [<ffffffff8103e6f8>] ? sched_clock+0x9/0xd [ 2866.132281] [<ffffffff810ee7f1>] ? trace_clock_local+0x9/0xb [ 2866.132281] [<ffffffff8189ae03>] kernel_sendmsg+0x37/0x43 [ 2866.132281] [<ffffffff8199ce49>] xs_send_kvec+0x77/0x80 [ 2866.132281] [<ffffffff8199cec1>] xs_sendpages+0x6f/0x1a0 [ 2866.132281] [<ffffffff8107826d>] ? try_to_del_timer_sync+0x55/0x61 [ 2866.132281] [<ffffffff8199d0d2>] xs_tcp_send_request+0x55/0xf1 [ 2866.132281] [<ffffffff8199bb90>] xprt_transmit+0x89/0x1db [ 2866.132281] [<ffffffff81999bcd>] ? call_connect+0x3c/0x3c [ 2866.132281] [<ffffffff81999d92>] call_transmit+0x1c5/0x20e [ 2866.132281] [<ffffffff819a0d55>] __rpc_execute+0x6f/0x225 [ 2866.132281] [<ffffffff81999bcd>] ? call_connect+0x3c/0x3c [ 2866.132281] [<ffffffff819a0f33>] rpc_async_schedule+0x28/0x34 [ 2866.132281] [<ffffffff810835d6>] process_one_work+0x24d/0x47f [ 2866.132281] [<ffffffff81083567>] ? process_one_work+0x1de/0x47f [ 2866.132281] [<ffffffff819a0f0b>] ? __rpc_execute+0x225/0x225 [ 2866.132281] [<ffffffff81083a6d>] worker_thread+0x236/0x317 [ 2866.132281] [<ffffffff81083837>] ? process_scheduled_works+0x2f/0x2f [ 2866.132281] [<ffffffff8108b7b8>] kthread+0x9a/0xa2 [ 2866.132281] [<ffffffff81a12184>] kernel_thread_helper+0x4/0x10 [ 2866.132281] [<ffffffff81a0a4b0>] ? retint_restore_args+0x13/0x13 [ 2866.132281] [<ffffffff8108b71e>] ? __init_kthread_worker+0x5a/0x5a [ 2866.132281] [<ffffffff81a12180>] ? gs_change+0x13/0x13 [ 2866.308506] IPv4: Attempt to release TCP socket in state 1 ffff880019ec0000 [ 2866.309689] ============================================================================= [ 2866.310254] BUG TCP (Not tainted): Object already free [ 2866.310254] ----------------------------------------------------------------------------- [ 2866.310254] The bug comes from the fact that timer set in sk_reset_timer() can run before we actually do the sock_hold(). socket refcount reaches zero and we free the socket too soon. timer handler is not allowed to reduce socket refcnt if socket is owned by the user, or we need to change sk_reset_timer() implementation. We should take a reference on the socket in case TCP_DELACK_TIMER_DEFERRED or TCP_DELACK_TIMER_DEFERRED bit are set in tsq_flags Also fix a typo in tcp_delack_timer(), where TCP_WRITE_TIMER_DEFERRED was used instead of TCP_DELACK_TIMER_DEFERRED. For consistency, use same socket refcount change for TCP_MTU_REDUCED_DEFERRED, even if not fired from a timer. Reported-by: Fengguang Wu <fengguang.wu@intel.com> Tested-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-08-20 08:22:46 +08:00
sock_hold(sk);
tcp: improve latencies of timer triggered events Modern TCP stack highly depends on tcp_write_timer() having a small latency, but current implementation doesn't exactly meet the expectations. When a timer fires but finds the socket is owned by the user, it rearms itself for an additional delay hoping next run will be more successful. tcp_write_timer() for example uses a 50ms delay for next try, and it defeats many attempts to get predictable TCP behavior in term of latencies. Use the recently introduced tcp_release_cb(), so that the user owning the socket will call various handlers right before socket release. This will permit us to post a followup patch to address the tcp_tso_should_defer() syndrome (some deferred packets have to wait RTO timer to be transmitted, while cwnd should allow us to send them sooner) Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Tom Herbert <therbert@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Nandita Dukkipati <nanditad@google.com> Cc: H.K. Jerry Chu <hkchu@google.com> Cc: John Heffner <johnwheffner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-07-20 13:45:50 +08:00
}
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
bh_unlock_sock(sk);
sock_put(sk);
}
static void tcp_probe_timer(struct sock *sk)
{
[ICSK]: Move TCP congestion avoidance members to icsk This changeset basically moves tcp_sk()->{ca_ops,ca_state,etc} to inet_csk(), minimal renaming/moving done in this changeset to ease review. Most of it is just changes of struct tcp_sock * to struct sock * parameters. With this we move to a state closer to two interesting goals: 1. Generalisation of net/ipv4/tcp_diag.c, becoming inet_diag.c, being used for any INET transport protocol that has struct inet_hashinfo and are derived from struct inet_connection_sock. Keeps the userspace API, that will just not display DCCP sockets, while newer versions of tools can support DCCP. 2. INET generic transport pluggable Congestion Avoidance infrastructure, using the current TCP CA infrastructure with DCCP. Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-10 15:03:31 +08:00
struct inet_connection_sock *icsk = inet_csk(sk);
tcp: implement rb-tree based retransmit queue Using a linear list to store all skbs in write queue has been okay for quite a while : O(N) is not too bad when N < 500. Things get messy when N is the order of 100,000 : Modern TCP stacks want 10Gbit+ of throughput even with 200 ms RTT flows. 40 ns per cache line miss means a full scan can use 4 ms, blowing away CPU caches. SACK processing often can use various hints to avoid parsing whole retransmit queue. But with high packet losses and/or high reordering, hints no longer work. Sender has to process thousands of unfriendly SACK, accumulating a huge socket backlog, burning a cpu and massively dropping packets. Using an rb-tree for retransmit queue has been avoided for years because it added complexity and overhead, but now is the time to be more resistant and say no to quadratic behavior. 1) RTX queue is no longer part of the write queue : already sent skbs are stored in one rb-tree. 2) Since reaching the head of write queue no longer needs sk->sk_send_head, we added an union of sk_send_head and tcp_rtx_queue Tested: On receiver : netem on ingress : delay 150ms 200us loss 1 GRO disabled to force stress and SACK storms. for f in `seq 1 10` do ./netperf -H lpaa6 -l30 -- -K bbr -o THROUGHPUT|tail -1 done | awk '{print $0} {sum += $0} END {printf "%7u\n",sum}' Before patch : 323.87 351.48 339.59 338.62 306.72 204.07 304.93 291.88 202.47 176.88 2840 After patch: 1700.83 2207.98 2070.17 1544.26 2114.76 2124.89 1693.14 1080.91 2216.82 1299.94 18053 Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-06 13:21:27 +08:00
struct sk_buff *skb = tcp_send_head(sk);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
struct tcp_sock *tp = tcp_sk(sk);
int max_probes;
tcp: abort orphan sockets stalling on zero window probes Currently we have two different policies for orphan sockets that repeatedly stall on zero window ACKs. If a socket gets a zero window ACK when it is transmitting data, the RTO is used to probe the window. The socket is aborted after roughly tcp_orphan_retries() retries (as in tcp_write_timeout()). But if the socket was idle when it received the zero window ACK, and later wants to send more data, we use the probe timer to probe the window. If the receiver always returns zero window ACKs, icsk_probes keeps getting reset in tcp_ack() and the orphan socket can stall forever until the system reaches the orphan limit (as commented in tcp_probe_timer()). This opens up a simple attack to create lots of hanging orphan sockets to burn the memory and the CPU, as demonstrated in the recent netdev post "TCP connection will hang in FIN_WAIT1 after closing if zero window is advertised." http://www.spinics.net/lists/netdev/msg296539.html This patch follows the design in RTO-based probe: we abort an orphan socket stalling on zero window when the probe timer reaches both the maximum backoff and the maximum RTO. For example, an 100ms RTT connection will timeout after roughly 153 seconds (0.3 + 0.6 + .... + 76.8) if the receiver keeps the window shut. If the orphan socket passes this check, but the system already has too many orphans (as in tcp_out_of_resources()), we still abort it but we'll also send an RST packet as the connection may still be active. In addition, we change TCP_USER_TIMEOUT to cover (life or dead) sockets stalled on zero-window probes. This changes the semantics of TCP_USER_TIMEOUT slightly because it previously only applies when the socket has pending transmission. Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Reported-by: Andrey Dmitrov <andrey.dmitrov@oktetlabs.ru> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-30 04:20:38 +08:00
u32 start_ts;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
tcp: implement rb-tree based retransmit queue Using a linear list to store all skbs in write queue has been okay for quite a while : O(N) is not too bad when N < 500. Things get messy when N is the order of 100,000 : Modern TCP stacks want 10Gbit+ of throughput even with 200 ms RTT flows. 40 ns per cache line miss means a full scan can use 4 ms, blowing away CPU caches. SACK processing often can use various hints to avoid parsing whole retransmit queue. But with high packet losses and/or high reordering, hints no longer work. Sender has to process thousands of unfriendly SACK, accumulating a huge socket backlog, burning a cpu and massively dropping packets. Using an rb-tree for retransmit queue has been avoided for years because it added complexity and overhead, but now is the time to be more resistant and say no to quadratic behavior. 1) RTX queue is no longer part of the write queue : already sent skbs are stored in one rb-tree. 2) Since reaching the head of write queue no longer needs sk->sk_send_head, we added an union of sk_send_head and tcp_rtx_queue Tested: On receiver : netem on ingress : delay 150ms 200us loss 1 GRO disabled to force stress and SACK storms. for f in `seq 1 10` do ./netperf -H lpaa6 -l30 -- -K bbr -o THROUGHPUT|tail -1 done | awk '{print $0} {sum += $0} END {printf "%7u\n",sum}' Before patch : 323.87 351.48 339.59 338.62 306.72 204.07 304.93 291.88 202.47 176.88 2840 After patch: 1700.83 2207.98 2070.17 1544.26 2114.76 2124.89 1693.14 1080.91 2216.82 1299.94 18053 Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-06 13:21:27 +08:00
if (tp->packets_out || !skb) {
[ICSK]: Move TCP congestion avoidance members to icsk This changeset basically moves tcp_sk()->{ca_ops,ca_state,etc} to inet_csk(), minimal renaming/moving done in this changeset to ease review. Most of it is just changes of struct tcp_sock * to struct sock * parameters. With this we move to a state closer to two interesting goals: 1. Generalisation of net/ipv4/tcp_diag.c, becoming inet_diag.c, being used for any INET transport protocol that has struct inet_hashinfo and are derived from struct inet_connection_sock. Keeps the userspace API, that will just not display DCCP sockets, while newer versions of tools can support DCCP. 2. INET generic transport pluggable Congestion Avoidance infrastructure, using the current TCP CA infrastructure with DCCP. Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-10 15:03:31 +08:00
icsk->icsk_probes_out = 0;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
return;
}
tcp: abort orphan sockets stalling on zero window probes Currently we have two different policies for orphan sockets that repeatedly stall on zero window ACKs. If a socket gets a zero window ACK when it is transmitting data, the RTO is used to probe the window. The socket is aborted after roughly tcp_orphan_retries() retries (as in tcp_write_timeout()). But if the socket was idle when it received the zero window ACK, and later wants to send more data, we use the probe timer to probe the window. If the receiver always returns zero window ACKs, icsk_probes keeps getting reset in tcp_ack() and the orphan socket can stall forever until the system reaches the orphan limit (as commented in tcp_probe_timer()). This opens up a simple attack to create lots of hanging orphan sockets to burn the memory and the CPU, as demonstrated in the recent netdev post "TCP connection will hang in FIN_WAIT1 after closing if zero window is advertised." http://www.spinics.net/lists/netdev/msg296539.html This patch follows the design in RTO-based probe: we abort an orphan socket stalling on zero window when the probe timer reaches both the maximum backoff and the maximum RTO. For example, an 100ms RTT connection will timeout after roughly 153 seconds (0.3 + 0.6 + .... + 76.8) if the receiver keeps the window shut. If the orphan socket passes this check, but the system already has too many orphans (as in tcp_out_of_resources()), we still abort it but we'll also send an RST packet as the connection may still be active. In addition, we change TCP_USER_TIMEOUT to cover (life or dead) sockets stalled on zero-window probes. This changes the semantics of TCP_USER_TIMEOUT slightly because it previously only applies when the socket has pending transmission. Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Reported-by: Andrey Dmitrov <andrey.dmitrov@oktetlabs.ru> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-30 04:20:38 +08:00
/* RFC 1122 4.2.2.17 requires the sender to stay open indefinitely as
* long as the receiver continues to respond probes. We support this by
* default and reset icsk_probes_out with incoming ACKs. But if the
* socket is orphaned or the user specifies TCP_USER_TIMEOUT, we
* kill the socket when the retry count and the time exceeds the
* corresponding system limit. We also implement similar policy when
* we use RTO to probe window in tcp_retransmit_timer().
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
*/
tcp: implement rb-tree based retransmit queue Using a linear list to store all skbs in write queue has been okay for quite a while : O(N) is not too bad when N < 500. Things get messy when N is the order of 100,000 : Modern TCP stacks want 10Gbit+ of throughput even with 200 ms RTT flows. 40 ns per cache line miss means a full scan can use 4 ms, blowing away CPU caches. SACK processing often can use various hints to avoid parsing whole retransmit queue. But with high packet losses and/or high reordering, hints no longer work. Sender has to process thousands of unfriendly SACK, accumulating a huge socket backlog, burning a cpu and massively dropping packets. Using an rb-tree for retransmit queue has been avoided for years because it added complexity and overhead, but now is the time to be more resistant and say no to quadratic behavior. 1) RTX queue is no longer part of the write queue : already sent skbs are stored in one rb-tree. 2) Since reaching the head of write queue no longer needs sk->sk_send_head, we added an union of sk_send_head and tcp_rtx_queue Tested: On receiver : netem on ingress : delay 150ms 200us loss 1 GRO disabled to force stress and SACK storms. for f in `seq 1 10` do ./netperf -H lpaa6 -l30 -- -K bbr -o THROUGHPUT|tail -1 done | awk '{print $0} {sum += $0} END {printf "%7u\n",sum}' Before patch : 323.87 351.48 339.59 338.62 306.72 204.07 304.93 291.88 202.47 176.88 2840 After patch: 1700.83 2207.98 2070.17 1544.26 2114.76 2124.89 1693.14 1080.91 2216.82 1299.94 18053 Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-06 13:21:27 +08:00
start_ts = tcp_skb_timestamp(skb);
tcp: abort orphan sockets stalling on zero window probes Currently we have two different policies for orphan sockets that repeatedly stall on zero window ACKs. If a socket gets a zero window ACK when it is transmitting data, the RTO is used to probe the window. The socket is aborted after roughly tcp_orphan_retries() retries (as in tcp_write_timeout()). But if the socket was idle when it received the zero window ACK, and later wants to send more data, we use the probe timer to probe the window. If the receiver always returns zero window ACKs, icsk_probes keeps getting reset in tcp_ack() and the orphan socket can stall forever until the system reaches the orphan limit (as commented in tcp_probe_timer()). This opens up a simple attack to create lots of hanging orphan sockets to burn the memory and the CPU, as demonstrated in the recent netdev post "TCP connection will hang in FIN_WAIT1 after closing if zero window is advertised." http://www.spinics.net/lists/netdev/msg296539.html This patch follows the design in RTO-based probe: we abort an orphan socket stalling on zero window when the probe timer reaches both the maximum backoff and the maximum RTO. For example, an 100ms RTT connection will timeout after roughly 153 seconds (0.3 + 0.6 + .... + 76.8) if the receiver keeps the window shut. If the orphan socket passes this check, but the system already has too many orphans (as in tcp_out_of_resources()), we still abort it but we'll also send an RST packet as the connection may still be active. In addition, we change TCP_USER_TIMEOUT to cover (life or dead) sockets stalled on zero-window probes. This changes the semantics of TCP_USER_TIMEOUT slightly because it previously only applies when the socket has pending transmission. Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Reported-by: Andrey Dmitrov <andrey.dmitrov@oktetlabs.ru> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-30 04:20:38 +08:00
if (!start_ts)
tcp: implement rb-tree based retransmit queue Using a linear list to store all skbs in write queue has been okay for quite a while : O(N) is not too bad when N < 500. Things get messy when N is the order of 100,000 : Modern TCP stacks want 10Gbit+ of throughput even with 200 ms RTT flows. 40 ns per cache line miss means a full scan can use 4 ms, blowing away CPU caches. SACK processing often can use various hints to avoid parsing whole retransmit queue. But with high packet losses and/or high reordering, hints no longer work. Sender has to process thousands of unfriendly SACK, accumulating a huge socket backlog, burning a cpu and massively dropping packets. Using an rb-tree for retransmit queue has been avoided for years because it added complexity and overhead, but now is the time to be more resistant and say no to quadratic behavior. 1) RTX queue is no longer part of the write queue : already sent skbs are stored in one rb-tree. 2) Since reaching the head of write queue no longer needs sk->sk_send_head, we added an union of sk_send_head and tcp_rtx_queue Tested: On receiver : netem on ingress : delay 150ms 200us loss 1 GRO disabled to force stress and SACK storms. for f in `seq 1 10` do ./netperf -H lpaa6 -l30 -- -K bbr -o THROUGHPUT|tail -1 done | awk '{print $0} {sum += $0} END {printf "%7u\n",sum}' Before patch : 323.87 351.48 339.59 338.62 306.72 204.07 304.93 291.88 202.47 176.88 2840 After patch: 1700.83 2207.98 2070.17 1544.26 2114.76 2124.89 1693.14 1080.91 2216.82 1299.94 18053 Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-06 13:21:27 +08:00
skb->skb_mstamp = tp->tcp_mstamp;
tcp: abort orphan sockets stalling on zero window probes Currently we have two different policies for orphan sockets that repeatedly stall on zero window ACKs. If a socket gets a zero window ACK when it is transmitting data, the RTO is used to probe the window. The socket is aborted after roughly tcp_orphan_retries() retries (as in tcp_write_timeout()). But if the socket was idle when it received the zero window ACK, and later wants to send more data, we use the probe timer to probe the window. If the receiver always returns zero window ACKs, icsk_probes keeps getting reset in tcp_ack() and the orphan socket can stall forever until the system reaches the orphan limit (as commented in tcp_probe_timer()). This opens up a simple attack to create lots of hanging orphan sockets to burn the memory and the CPU, as demonstrated in the recent netdev post "TCP connection will hang in FIN_WAIT1 after closing if zero window is advertised." http://www.spinics.net/lists/netdev/msg296539.html This patch follows the design in RTO-based probe: we abort an orphan socket stalling on zero window when the probe timer reaches both the maximum backoff and the maximum RTO. For example, an 100ms RTT connection will timeout after roughly 153 seconds (0.3 + 0.6 + .... + 76.8) if the receiver keeps the window shut. If the orphan socket passes this check, but the system already has too many orphans (as in tcp_out_of_resources()), we still abort it but we'll also send an RST packet as the connection may still be active. In addition, we change TCP_USER_TIMEOUT to cover (life or dead) sockets stalled on zero-window probes. This changes the semantics of TCP_USER_TIMEOUT slightly because it previously only applies when the socket has pending transmission. Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Reported-by: Andrey Dmitrov <andrey.dmitrov@oktetlabs.ru> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-30 04:20:38 +08:00
else if (icsk->icsk_user_timeout &&
tcp: fix tcp_probe_timer() for TCP_USER_TIMEOUT TCP_USER_TIMEOUT is still converted to jiffies value in icsk_user_timeout So we need to make a conversion for the cases HZ != 1000 Fixes: 9a568de4818d ("tcp: switch TCP TS option (RFC 7323) to 1ms clock") Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-22 01:39:00 +08:00
(s32)(tcp_time_stamp(tp) - start_ts) >
jiffies_to_msecs(icsk->icsk_user_timeout))
tcp: abort orphan sockets stalling on zero window probes Currently we have two different policies for orphan sockets that repeatedly stall on zero window ACKs. If a socket gets a zero window ACK when it is transmitting data, the RTO is used to probe the window. The socket is aborted after roughly tcp_orphan_retries() retries (as in tcp_write_timeout()). But if the socket was idle when it received the zero window ACK, and later wants to send more data, we use the probe timer to probe the window. If the receiver always returns zero window ACKs, icsk_probes keeps getting reset in tcp_ack() and the orphan socket can stall forever until the system reaches the orphan limit (as commented in tcp_probe_timer()). This opens up a simple attack to create lots of hanging orphan sockets to burn the memory and the CPU, as demonstrated in the recent netdev post "TCP connection will hang in FIN_WAIT1 after closing if zero window is advertised." http://www.spinics.net/lists/netdev/msg296539.html This patch follows the design in RTO-based probe: we abort an orphan socket stalling on zero window when the probe timer reaches both the maximum backoff and the maximum RTO. For example, an 100ms RTT connection will timeout after roughly 153 seconds (0.3 + 0.6 + .... + 76.8) if the receiver keeps the window shut. If the orphan socket passes this check, but the system already has too many orphans (as in tcp_out_of_resources()), we still abort it but we'll also send an RST packet as the connection may still be active. In addition, we change TCP_USER_TIMEOUT to cover (life or dead) sockets stalled on zero-window probes. This changes the semantics of TCP_USER_TIMEOUT slightly because it previously only applies when the socket has pending transmission. Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Reported-by: Andrey Dmitrov <andrey.dmitrov@oktetlabs.ru> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-30 04:20:38 +08:00
goto abort;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
ipv4: Namespaceify tcp_retries2 sysctl knob Signed-off-by: Nikolay Borisov <kernel@kyup.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-02-03 15:46:54 +08:00
max_probes = sock_net(sk)->ipv4.sysctl_tcp_retries2;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
if (sock_flag(sk, SOCK_DEAD)) {
tcp: change type of alive from int to bool The alive parameter of tcp_orphan_retries, indicates whether the connection is assumed alive or not. In the function and all places calling it is used as a boolean value. Therefore this changes the type of alive to bool in the function definition and all calling locations. Since tcp_orphan_tries is a tcp_timer.c local function no change in any other file or header is necessary. Signed-off-by: Richard Sailer <richard@weltraumpflege.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-10-09 08:41:37 +08:00
const bool alive = inet_csk_rto_backoff(icsk, TCP_RTO_MAX) < TCP_RTO_MAX;
[NET] IPV4: Fix whitespace errors. Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-02-09 22:24:47 +08:00
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
max_probes = tcp_orphan_retries(sk, alive);
tcp: abort orphan sockets stalling on zero window probes Currently we have two different policies for orphan sockets that repeatedly stall on zero window ACKs. If a socket gets a zero window ACK when it is transmitting data, the RTO is used to probe the window. The socket is aborted after roughly tcp_orphan_retries() retries (as in tcp_write_timeout()). But if the socket was idle when it received the zero window ACK, and later wants to send more data, we use the probe timer to probe the window. If the receiver always returns zero window ACKs, icsk_probes keeps getting reset in tcp_ack() and the orphan socket can stall forever until the system reaches the orphan limit (as commented in tcp_probe_timer()). This opens up a simple attack to create lots of hanging orphan sockets to burn the memory and the CPU, as demonstrated in the recent netdev post "TCP connection will hang in FIN_WAIT1 after closing if zero window is advertised." http://www.spinics.net/lists/netdev/msg296539.html This patch follows the design in RTO-based probe: we abort an orphan socket stalling on zero window when the probe timer reaches both the maximum backoff and the maximum RTO. For example, an 100ms RTT connection will timeout after roughly 153 seconds (0.3 + 0.6 + .... + 76.8) if the receiver keeps the window shut. If the orphan socket passes this check, but the system already has too many orphans (as in tcp_out_of_resources()), we still abort it but we'll also send an RST packet as the connection may still be active. In addition, we change TCP_USER_TIMEOUT to cover (life or dead) sockets stalled on zero-window probes. This changes the semantics of TCP_USER_TIMEOUT slightly because it previously only applies when the socket has pending transmission. Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Reported-by: Andrey Dmitrov <andrey.dmitrov@oktetlabs.ru> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-30 04:20:38 +08:00
if (!alive && icsk->icsk_backoff >= max_probes)
goto abort;
if (tcp_out_of_resources(sk, true))
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
return;
}
[ICSK]: Move TCP congestion avoidance members to icsk This changeset basically moves tcp_sk()->{ca_ops,ca_state,etc} to inet_csk(), minimal renaming/moving done in this changeset to ease review. Most of it is just changes of struct tcp_sock * to struct sock * parameters. With this we move to a state closer to two interesting goals: 1. Generalisation of net/ipv4/tcp_diag.c, becoming inet_diag.c, being used for any INET transport protocol that has struct inet_hashinfo and are derived from struct inet_connection_sock. Keeps the userspace API, that will just not display DCCP sockets, while newer versions of tools can support DCCP. 2. INET generic transport pluggable Congestion Avoidance infrastructure, using the current TCP CA infrastructure with DCCP. Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-10 15:03:31 +08:00
if (icsk->icsk_probes_out > max_probes) {
tcp: abort orphan sockets stalling on zero window probes Currently we have two different policies for orphan sockets that repeatedly stall on zero window ACKs. If a socket gets a zero window ACK when it is transmitting data, the RTO is used to probe the window. The socket is aborted after roughly tcp_orphan_retries() retries (as in tcp_write_timeout()). But if the socket was idle when it received the zero window ACK, and later wants to send more data, we use the probe timer to probe the window. If the receiver always returns zero window ACKs, icsk_probes keeps getting reset in tcp_ack() and the orphan socket can stall forever until the system reaches the orphan limit (as commented in tcp_probe_timer()). This opens up a simple attack to create lots of hanging orphan sockets to burn the memory and the CPU, as demonstrated in the recent netdev post "TCP connection will hang in FIN_WAIT1 after closing if zero window is advertised." http://www.spinics.net/lists/netdev/msg296539.html This patch follows the design in RTO-based probe: we abort an orphan socket stalling on zero window when the probe timer reaches both the maximum backoff and the maximum RTO. For example, an 100ms RTT connection will timeout after roughly 153 seconds (0.3 + 0.6 + .... + 76.8) if the receiver keeps the window shut. If the orphan socket passes this check, but the system already has too many orphans (as in tcp_out_of_resources()), we still abort it but we'll also send an RST packet as the connection may still be active. In addition, we change TCP_USER_TIMEOUT to cover (life or dead) sockets stalled on zero-window probes. This changes the semantics of TCP_USER_TIMEOUT slightly because it previously only applies when the socket has pending transmission. Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Reported-by: Andrey Dmitrov <andrey.dmitrov@oktetlabs.ru> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-30 04:20:38 +08:00
abort: tcp_write_err(sk);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
} else {
/* Only send another probe if we didn't close things up. */
tcp_send_probe0(sk);
}
}
tcp: TCP Fast Open Server - support TFO listeners This patch builds on top of the previous patch to add the support for TFO listeners. This includes - 1. allocating, properly initializing, and managing the per listener fastopen_queue structure when TFO is enabled 2. changes to the inet_csk_accept code to support TFO. E.g., the request_sock can no longer be freed upon accept(), not until 3WHS finishes 3. allowing a TCP_SYN_RECV socket to properly poll() and sendmsg() if it's a TFO socket 4. properly closing a TFO listener, and a TFO socket before 3WHS finishes 5. supporting TCP_FASTOPEN socket option 6. modifying tcp_check_req() to use to check a TFO socket as well as request_sock 7. supporting TCP's TFO cookie option 8. adding a new SYN-ACK retransmit handler to use the timer directly off the TFO socket rather than the listener socket. Note that TFO server side will not retransmit anything other than SYN-ACK until the 3WHS is completed. The patch also contains an important function "reqsk_fastopen_remove()" to manage the somewhat complex relation between a listener, its request_sock, and the corresponding child socket. See the comment above the function for the detail. Signed-off-by: H.K. Jerry Chu <hkchu@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Tom Herbert <therbert@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-08-31 20:29:12 +08:00
/*
* Timer for Fast Open socket to retransmit SYNACK. Note that the
* sk here is the child socket, not the parent (listener) socket.
*/
static void tcp_fastopen_synack_timer(struct sock *sk)
{
struct inet_connection_sock *icsk = inet_csk(sk);
int max_retries = icsk->icsk_syn_retries ? :
ipv4: Namespaceify tcp synack retries sysctl knob Signed-off-by: Nikolay Borisov <kernel@kyup.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-02-03 15:46:50 +08:00
sock_net(sk)->ipv4.sysctl_tcp_synack_retries + 1; /* add one more retry for fastopen */
tcp: TCP Fast Open Server - support TFO listeners This patch builds on top of the previous patch to add the support for TFO listeners. This includes - 1. allocating, properly initializing, and managing the per listener fastopen_queue structure when TFO is enabled 2. changes to the inet_csk_accept code to support TFO. E.g., the request_sock can no longer be freed upon accept(), not until 3WHS finishes 3. allowing a TCP_SYN_RECV socket to properly poll() and sendmsg() if it's a TFO socket 4. properly closing a TFO listener, and a TFO socket before 3WHS finishes 5. supporting TCP_FASTOPEN socket option 6. modifying tcp_check_req() to use to check a TFO socket as well as request_sock 7. supporting TCP's TFO cookie option 8. adding a new SYN-ACK retransmit handler to use the timer directly off the TFO socket rather than the listener socket. Note that TFO server side will not retransmit anything other than SYN-ACK until the 3WHS is completed. The patch also contains an important function "reqsk_fastopen_remove()" to manage the somewhat complex relation between a listener, its request_sock, and the corresponding child socket. See the comment above the function for the detail. Signed-off-by: H.K. Jerry Chu <hkchu@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Tom Herbert <therbert@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-08-31 20:29:12 +08:00
struct request_sock *req;
req = tcp_sk(sk)->fastopen_rsk;
inet: remove sk_listener parameter from syn_ack_timeout() It is not needed, and req->sk_listener points to the listener anyway. request_sock argument can be const. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-23 01:22:19 +08:00
req->rsk_ops->syn_ack_timeout(req);
tcp: TCP Fast Open Server - support TFO listeners This patch builds on top of the previous patch to add the support for TFO listeners. This includes - 1. allocating, properly initializing, and managing the per listener fastopen_queue structure when TFO is enabled 2. changes to the inet_csk_accept code to support TFO. E.g., the request_sock can no longer be freed upon accept(), not until 3WHS finishes 3. allowing a TCP_SYN_RECV socket to properly poll() and sendmsg() if it's a TFO socket 4. properly closing a TFO listener, and a TFO socket before 3WHS finishes 5. supporting TCP_FASTOPEN socket option 6. modifying tcp_check_req() to use to check a TFO socket as well as request_sock 7. supporting TCP's TFO cookie option 8. adding a new SYN-ACK retransmit handler to use the timer directly off the TFO socket rather than the listener socket. Note that TFO server side will not retransmit anything other than SYN-ACK until the 3WHS is completed. The patch also contains an important function "reqsk_fastopen_remove()" to manage the somewhat complex relation between a listener, its request_sock, and the corresponding child socket. See the comment above the function for the detail. Signed-off-by: H.K. Jerry Chu <hkchu@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Tom Herbert <therbert@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-08-31 20:29:12 +08:00
tcp: better retrans tracking for defer-accept For passive TCP connections using TCP_DEFER_ACCEPT facility, we incorrectly increment req->retrans each time timeout triggers while no SYNACK is sent. SYNACK are not sent for TCP_DEFER_ACCEPT that were established (for which we received the ACK from client). Only the last SYNACK is sent so that we can receive again an ACK from client, to move the req into accept queue. We plan to change this later to avoid the useless retransmit (and potential problem as this SYNACK could be lost) TCP_INFO later gives wrong information to user, claiming imaginary retransmits. Decouple req->retrans field into two independent fields : num_retrans : number of retransmit num_timeout : number of timeouts num_timeout is the counter that is incremented at each timeout, regardless of actual SYNACK being sent or not, and used to compute the exponential timeout. Introduce inet_rtx_syn_ack() helper to increment num_retrans only if ->rtx_syn_ack() succeeded. Use inet_rtx_syn_ack() from tcp_check_req() to increment num_retrans when we re-send a SYNACK in answer to a (retransmitted) SYN. Prior to this patch, we were not counting these retransmits. Change tcp_v[46]_rtx_synack() to increment TCP_MIB_RETRANSSEGS only if a synack packet was successfully queued. Reported-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Julian Anastasov <ja@ssi.bg> Cc: Vijay Subramanian <subramanian.vijay@gmail.com> Cc: Elliott Hughes <enh@google.com> Cc: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-10-28 07:16:46 +08:00
if (req->num_timeout >= max_retries) {
tcp: TCP Fast Open Server - support TFO listeners This patch builds on top of the previous patch to add the support for TFO listeners. This includes - 1. allocating, properly initializing, and managing the per listener fastopen_queue structure when TFO is enabled 2. changes to the inet_csk_accept code to support TFO. E.g., the request_sock can no longer be freed upon accept(), not until 3WHS finishes 3. allowing a TCP_SYN_RECV socket to properly poll() and sendmsg() if it's a TFO socket 4. properly closing a TFO listener, and a TFO socket before 3WHS finishes 5. supporting TCP_FASTOPEN socket option 6. modifying tcp_check_req() to use to check a TFO socket as well as request_sock 7. supporting TCP's TFO cookie option 8. adding a new SYN-ACK retransmit handler to use the timer directly off the TFO socket rather than the listener socket. Note that TFO server side will not retransmit anything other than SYN-ACK until the 3WHS is completed. The patch also contains an important function "reqsk_fastopen_remove()" to manage the somewhat complex relation between a listener, its request_sock, and the corresponding child socket. See the comment above the function for the detail. Signed-off-by: H.K. Jerry Chu <hkchu@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Tom Herbert <therbert@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-08-31 20:29:12 +08:00
tcp_write_err(sk);
return;
}
/* XXX (TFO) - Unlike regular SYN-ACK retransmit, we ignore error
* returned from rtx_syn_ack() to make it more persistent like
* regular retransmit because if the child socket has been accepted
* it's not good to give up too easily.
*/
tcp: better retrans tracking for defer-accept For passive TCP connections using TCP_DEFER_ACCEPT facility, we incorrectly increment req->retrans each time timeout triggers while no SYNACK is sent. SYNACK are not sent for TCP_DEFER_ACCEPT that were established (for which we received the ACK from client). Only the last SYNACK is sent so that we can receive again an ACK from client, to move the req into accept queue. We plan to change this later to avoid the useless retransmit (and potential problem as this SYNACK could be lost) TCP_INFO later gives wrong information to user, claiming imaginary retransmits. Decouple req->retrans field into two independent fields : num_retrans : number of retransmit num_timeout : number of timeouts num_timeout is the counter that is incremented at each timeout, regardless of actual SYNACK being sent or not, and used to compute the exponential timeout. Introduce inet_rtx_syn_ack() helper to increment num_retrans only if ->rtx_syn_ack() succeeded. Use inet_rtx_syn_ack() from tcp_check_req() to increment num_retrans when we re-send a SYNACK in answer to a (retransmitted) SYN. Prior to this patch, we were not counting these retransmits. Change tcp_v[46]_rtx_synack() to increment TCP_MIB_RETRANSSEGS only if a synack packet was successfully queued. Reported-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Julian Anastasov <ja@ssi.bg> Cc: Vijay Subramanian <subramanian.vijay@gmail.com> Cc: Elliott Hughes <enh@google.com> Cc: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-10-28 07:16:46 +08:00
inet_rtx_syn_ack(sk, req);
req->num_timeout++;
tcp: properly account Fast Open SYN-ACK retrans Since the TFO socket is accepted right off SYN-data, the socket owner can call getsockopt(TCP_INFO) to collect ongoing SYN-ACK retransmission or timeout stats (i.e., tcpi_total_retrans, tcpi_retransmits). Currently those stats are only updated upon handshake completes. This patch fixes it. Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-09-22 07:16:15 +08:00
icsk->icsk_retransmits++;
tcp: TCP Fast Open Server - support TFO listeners This patch builds on top of the previous patch to add the support for TFO listeners. This includes - 1. allocating, properly initializing, and managing the per listener fastopen_queue structure when TFO is enabled 2. changes to the inet_csk_accept code to support TFO. E.g., the request_sock can no longer be freed upon accept(), not until 3WHS finishes 3. allowing a TCP_SYN_RECV socket to properly poll() and sendmsg() if it's a TFO socket 4. properly closing a TFO listener, and a TFO socket before 3WHS finishes 5. supporting TCP_FASTOPEN socket option 6. modifying tcp_check_req() to use to check a TFO socket as well as request_sock 7. supporting TCP's TFO cookie option 8. adding a new SYN-ACK retransmit handler to use the timer directly off the TFO socket rather than the listener socket. Note that TFO server side will not retransmit anything other than SYN-ACK until the 3WHS is completed. The patch also contains an important function "reqsk_fastopen_remove()" to manage the somewhat complex relation between a listener, its request_sock, and the corresponding child socket. See the comment above the function for the detail. Signed-off-by: H.K. Jerry Chu <hkchu@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Tom Herbert <therbert@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-08-31 20:29:12 +08:00
inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
tcp: better retrans tracking for defer-accept For passive TCP connections using TCP_DEFER_ACCEPT facility, we incorrectly increment req->retrans each time timeout triggers while no SYNACK is sent. SYNACK are not sent for TCP_DEFER_ACCEPT that were established (for which we received the ACK from client). Only the last SYNACK is sent so that we can receive again an ACK from client, to move the req into accept queue. We plan to change this later to avoid the useless retransmit (and potential problem as this SYNACK could be lost) TCP_INFO later gives wrong information to user, claiming imaginary retransmits. Decouple req->retrans field into two independent fields : num_retrans : number of retransmit num_timeout : number of timeouts num_timeout is the counter that is incremented at each timeout, regardless of actual SYNACK being sent or not, and used to compute the exponential timeout. Introduce inet_rtx_syn_ack() helper to increment num_retrans only if ->rtx_syn_ack() succeeded. Use inet_rtx_syn_ack() from tcp_check_req() to increment num_retrans when we re-send a SYNACK in answer to a (retransmitted) SYN. Prior to this patch, we were not counting these retransmits. Change tcp_v[46]_rtx_synack() to increment TCP_MIB_RETRANSSEGS only if a synack packet was successfully queued. Reported-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Julian Anastasov <ja@ssi.bg> Cc: Vijay Subramanian <subramanian.vijay@gmail.com> Cc: Elliott Hughes <enh@google.com> Cc: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-10-28 07:16:46 +08:00
TCP_TIMEOUT_INIT << req->num_timeout, TCP_RTO_MAX);
tcp: TCP Fast Open Server - support TFO listeners This patch builds on top of the previous patch to add the support for TFO listeners. This includes - 1. allocating, properly initializing, and managing the per listener fastopen_queue structure when TFO is enabled 2. changes to the inet_csk_accept code to support TFO. E.g., the request_sock can no longer be freed upon accept(), not until 3WHS finishes 3. allowing a TCP_SYN_RECV socket to properly poll() and sendmsg() if it's a TFO socket 4. properly closing a TFO listener, and a TFO socket before 3WHS finishes 5. supporting TCP_FASTOPEN socket option 6. modifying tcp_check_req() to use to check a TFO socket as well as request_sock 7. supporting TCP's TFO cookie option 8. adding a new SYN-ACK retransmit handler to use the timer directly off the TFO socket rather than the listener socket. Note that TFO server side will not retransmit anything other than SYN-ACK until the 3WHS is completed. The patch also contains an important function "reqsk_fastopen_remove()" to manage the somewhat complex relation between a listener, its request_sock, and the corresponding child socket. See the comment above the function for the detail. Signed-off-by: H.K. Jerry Chu <hkchu@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Tom Herbert <therbert@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-08-31 20:29:12 +08:00
}
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
tcp_timer.c: Add kernel-doc function descriptions This adds kernel-doc style descriptions for 6 functions and fixes 1 typo. Signed-off-by: Richard Sailer <richard@weltraumpflege.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-07-16 10:04:34 +08:00
/**
* tcp_retransmit_timer() - The TCP retransmit timeout handler
* @sk: Pointer to the current socket.
*
* This function gets called when the kernel timer for a TCP packet
* of this socket expires.
*
* It handles retransmission, timer adjustment and other necesarry measures.
*
* Returns: Nothing (void)
*/
Revert Backoff [v3]: Revert RTO on ICMP destination unreachable Here, an ICMP host/network unreachable message, whose payload fits to TCP's SND.UNA, is taken as an indication that the RTO retransmission has not been lost due to congestion, but because of a route failure somewhere along the path. With true congestion, a router won't trigger such a message and the patched TCP will operate as standard TCP. This patch reverts one RTO backoff, if an ICMP host/network unreachable message, whose payload fits to TCP's SND.UNA, arrives. Based on the new RTO, the retransmission timer is reset to reflect the remaining time, or - if the revert clocked out the timer - a retransmission is sent out immediately. Backoffs are only reverted, if TCP is in RTO loss recovery, i.e. if there have been retransmissions and reversible backoffs, already. Changes from v2: 1) Renaming of skb in tcp_v4_err() moved to another patch. 2) Reintroduced tcp_bound_rto() and __tcp_set_rto(). 3) Fixed code comments. Signed-off-by: Damian Lukowski <damian@tvk.rwth-aachen.de> Acked-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-08-26 08:16:31 +08:00
void tcp_retransmit_timer(struct sock *sk)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
{
struct tcp_sock *tp = tcp_sk(sk);
ipv4: Namespaceify tcp_retries1 sysctl knob Signed-off-by: Nikolay Borisov <kernel@kyup.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-02-03 15:46:53 +08:00
struct net *net = sock_net(sk);
[NET]: Introduce inet_connection_sock This creates struct inet_connection_sock, moving members out of struct tcp_sock that are shareable with other INET connection oriented protocols, such as DCCP, that in my private tree already uses most of these members. The functions that operate on these members were renamed, using a inet_csk_ prefix while not being moved yet to a new file, so as to ease the review of these changes. Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-10 11:10:42 +08:00
struct inet_connection_sock *icsk = inet_csk(sk);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
tcp: TCP Fast Open Server - support TFO listeners This patch builds on top of the previous patch to add the support for TFO listeners. This includes - 1. allocating, properly initializing, and managing the per listener fastopen_queue structure when TFO is enabled 2. changes to the inet_csk_accept code to support TFO. E.g., the request_sock can no longer be freed upon accept(), not until 3WHS finishes 3. allowing a TCP_SYN_RECV socket to properly poll() and sendmsg() if it's a TFO socket 4. properly closing a TFO listener, and a TFO socket before 3WHS finishes 5. supporting TCP_FASTOPEN socket option 6. modifying tcp_check_req() to use to check a TFO socket as well as request_sock 7. supporting TCP's TFO cookie option 8. adding a new SYN-ACK retransmit handler to use the timer directly off the TFO socket rather than the listener socket. Note that TFO server side will not retransmit anything other than SYN-ACK until the 3WHS is completed. The patch also contains an important function "reqsk_fastopen_remove()" to manage the somewhat complex relation between a listener, its request_sock, and the corresponding child socket. See the comment above the function for the detail. Signed-off-by: H.K. Jerry Chu <hkchu@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Tom Herbert <therbert@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-08-31 20:29:12 +08:00
if (tp->fastopen_rsk) {
tcp: Reject invalid ack_seq to Fast Open sockets A packet with an invalid ack_seq may cause a TCP Fast Open socket to switch to the unexpected TCP_CLOSING state, triggering a BUG_ON kernel panic. When a FIN packet with an invalid ack_seq# arrives at a socket in the TCP_FIN_WAIT1 state, rather than discarding the packet, the current code will accept the FIN, causing state transition to TCP_CLOSING. This may be a small deviation from RFC793, which seems to say that the packet should be dropped. Unfortunately I did not expect this case for Fast Open hence it will trigger a BUG_ON panic. It turns out there is really nothing bad about a TFO socket going into TCP_CLOSING state so I could just remove the BUG_ON statements. But after some thought I think it's better to treat this case like TCP_SYN_RECV and return a RST to the confused peer who caused the unacceptable ack_seq to be generated in the first place. Signed-off-by: H.K. Jerry Chu <hkchu@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Yuchung Cheng <ycheng@google.com> Acked-by: Yuchung Cheng <ycheng@google.com> Acked-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-10-22 19:26:36 +08:00
WARN_ON_ONCE(sk->sk_state != TCP_SYN_RECV &&
sk->sk_state != TCP_FIN_WAIT1);
tcp: TCP Fast Open Server - support TFO listeners This patch builds on top of the previous patch to add the support for TFO listeners. This includes - 1. allocating, properly initializing, and managing the per listener fastopen_queue structure when TFO is enabled 2. changes to the inet_csk_accept code to support TFO. E.g., the request_sock can no longer be freed upon accept(), not until 3WHS finishes 3. allowing a TCP_SYN_RECV socket to properly poll() and sendmsg() if it's a TFO socket 4. properly closing a TFO listener, and a TFO socket before 3WHS finishes 5. supporting TCP_FASTOPEN socket option 6. modifying tcp_check_req() to use to check a TFO socket as well as request_sock 7. supporting TCP's TFO cookie option 8. adding a new SYN-ACK retransmit handler to use the timer directly off the TFO socket rather than the listener socket. Note that TFO server side will not retransmit anything other than SYN-ACK until the 3WHS is completed. The patch also contains an important function "reqsk_fastopen_remove()" to manage the somewhat complex relation between a listener, its request_sock, and the corresponding child socket. See the comment above the function for the detail. Signed-off-by: H.K. Jerry Chu <hkchu@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Tom Herbert <therbert@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-08-31 20:29:12 +08:00
tcp_fastopen_synack_timer(sk);
/* Before we receive ACK to our SYN-ACK don't retransmit
* anything else (e.g., data or FIN segments).
*/
return;
}
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
if (!tp->packets_out)
goto out;
tcp: implement rb-tree based retransmit queue Using a linear list to store all skbs in write queue has been okay for quite a while : O(N) is not too bad when N < 500. Things get messy when N is the order of 100,000 : Modern TCP stacks want 10Gbit+ of throughput even with 200 ms RTT flows. 40 ns per cache line miss means a full scan can use 4 ms, blowing away CPU caches. SACK processing often can use various hints to avoid parsing whole retransmit queue. But with high packet losses and/or high reordering, hints no longer work. Sender has to process thousands of unfriendly SACK, accumulating a huge socket backlog, burning a cpu and massively dropping packets. Using an rb-tree for retransmit queue has been avoided for years because it added complexity and overhead, but now is the time to be more resistant and say no to quadratic behavior. 1) RTX queue is no longer part of the write queue : already sent skbs are stored in one rb-tree. 2) Since reaching the head of write queue no longer needs sk->sk_send_head, we added an union of sk_send_head and tcp_rtx_queue Tested: On receiver : netem on ingress : delay 150ms 200us loss 1 GRO disabled to force stress and SACK storms. for f in `seq 1 10` do ./netperf -H lpaa6 -l30 -- -K bbr -o THROUGHPUT|tail -1 done | awk '{print $0} {sum += $0} END {printf "%7u\n",sum}' Before patch : 323.87 351.48 339.59 338.62 306.72 204.07 304.93 291.88 202.47 176.88 2840 After patch: 1700.83 2207.98 2070.17 1544.26 2114.76 2124.89 1693.14 1080.91 2216.82 1299.94 18053 Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-06 13:21:27 +08:00
WARN_ON(tcp_rtx_queue_empty(sk));
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
tcp: TLP loss detection. This is the second of the TLP patch series; it augments the basic TLP algorithm with a loss detection scheme. This patch implements a mechanism for loss detection when a Tail loss probe retransmission plugs a hole thereby masking packet loss from the sender. The loss detection algorithm relies on counting TLP dupacks as outlined in Sec. 3 of: http://tools.ietf.org/html/draft-dukkipati-tcpm-tcp-loss-probe-01 The basic idea is: Sender keeps track of TLP "episode" upon retransmission of a TLP packet. An episode ends when the sender receives an ACK above the SND.NXT (tracked by tlp_high_seq) at the time of the episode. We want to make sure that before the episode ends the sender receives a "TLP dupack", indicating that the TLP retransmission was unnecessary, so there was no loss/hole that needed plugging. If the sender gets no TLP dupack before the end of the episode, then it reduces ssthresh and the congestion window, because the TLP packet arriving at the receiver probably plugged a hole. Signed-off-by: Nandita Dukkipati <nanditad@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-03-11 18:00:44 +08:00
tp->tlp_high_seq = 0;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
if (!tp->snd_wnd && !sock_flag(sk, SOCK_DEAD) &&
!((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))) {
/* Receiver dastardly shrinks window. Our retransmits
* become zero probes, but we should not timeout this
* connection. If the socket is an orphan, time it out,
* we cannot allow such beasts to hang infinitely.
*/
[TCP]: Format addresses appropriately in debug messages. Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-04-14 19:09:36 +08:00
struct inet_sock *inet = inet_sk(sk);
if (sk->sk_family == AF_INET) {
net: Convert LIMIT_NETDEBUG to net_dbg_ratelimited Use the more common dynamic_debug capable net_dbg_ratelimited and remove the LIMIT_NETDEBUG macro. All messages are still ratelimited. Some KERN_<LEVEL> uses are changed to KERN_DEBUG. This may have some negative impact on messages that were emitted at KERN_INFO that are not not enabled at all unless DEBUG is defined or dynamic_debug is enabled. Even so, these messages are now _not_ emitted by default. This also eliminates the use of the net_msg_warn sysctl "/proc/sys/net/core/warnings". For backward compatibility, the sysctl is not removed, but it has no function. The extern declaration of net_msg_warn is removed from sock.h and made static in net/core/sysctl_net_core.c Miscellanea: o Update the sysctl documentation o Remove the embedded uses of pr_fmt o Coalesce format fragments o Realign arguments Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-11-12 02:59:17 +08:00
net_dbg_ratelimited("Peer %pI4:%u/%u unexpectedly shrunk window %u:%u (repaired)\n",
&inet->inet_daddr,
ntohs(inet->inet_dport),
inet->inet_num,
tp->snd_una, tp->snd_nxt);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
}
net: use IS_ENABLED(CONFIG_IPV6) Instead of testing defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-12-10 17:48:31 +08:00
#if IS_ENABLED(CONFIG_IPV6)
[TCP]: Format addresses appropriately in debug messages. Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-04-14 19:09:36 +08:00
else if (sk->sk_family == AF_INET6) {
net: Convert LIMIT_NETDEBUG to net_dbg_ratelimited Use the more common dynamic_debug capable net_dbg_ratelimited and remove the LIMIT_NETDEBUG macro. All messages are still ratelimited. Some KERN_<LEVEL> uses are changed to KERN_DEBUG. This may have some negative impact on messages that were emitted at KERN_INFO that are not not enabled at all unless DEBUG is defined or dynamic_debug is enabled. Even so, these messages are now _not_ emitted by default. This also eliminates the use of the net_msg_warn sysctl "/proc/sys/net/core/warnings". For backward compatibility, the sysctl is not removed, but it has no function. The extern declaration of net_msg_warn is removed from sock.h and made static in net/core/sysctl_net_core.c Miscellanea: o Update the sysctl documentation o Remove the embedded uses of pr_fmt o Coalesce format fragments o Realign arguments Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-11-12 02:59:17 +08:00
net_dbg_ratelimited("Peer %pI6:%u/%u unexpectedly shrunk window %u:%u (repaired)\n",
&sk->sk_v6_daddr,
ntohs(inet->inet_dport),
inet->inet_num,
tp->snd_una, tp->snd_nxt);
[TCP]: Format addresses appropriately in debug messages. Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-04-14 19:09:36 +08:00
}
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
#endif
tcp: use tcp_jiffies32 for rcv_tstamp and lrcvtime Use tcp_jiffies32 instead of tcp_time_stamp, since tcp_time_stamp will soon be only used for TCP TS option. Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-17 05:00:07 +08:00
if (tcp_jiffies32 - tp->rcv_tstamp > TCP_RTO_MAX) {
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
tcp_write_err(sk);
goto out;
}
tcp: reduce spurious retransmits due to transient SACK reneging This commit reduces spurious retransmits due to apparent SACK reneging by only reacting to SACK reneging that persists for a short delay. When a sequence space hole at snd_una is filled, some TCP receivers send a series of ACKs as they apparently scan their out-of-order queue and cumulatively ACK all the packets that have now been consecutiveyly received. This is essentially misbehavior B in "Misbehaviors in TCP SACK generation" ACM SIGCOMM Computer Communication Review, April 2011, so we suspect that this is from several common OSes (Windows 2000, Windows Server 2003, Windows XP). However, this issue has also been seen in other cases, e.g. the netdev thread "TCP being hoodwinked into spurious retransmissions by lack of timestamps?" from March 2014, where the receiver was thought to be a BSD box. Since snd_una would temporarily be adjacent to a previously SACKed range in these scenarios, this receiver behavior triggered the Linux SACK reneging code path in the sender. This led the sender to clear the SACK scoreboard, enter CA_Loss, and spuriously retransmit (potentially) every packet from the entire write queue at line rate just a few milliseconds before the ACK for each packet arrives at the sender. To avoid such situations, now when a sender sees apparent reneging it does not yet retransmit, but rather adjusts the RTO timer to give the receiver a little time (max(RTT/2, 10ms)) to send us some more ACKs that will restore sanity to the SACK scoreboard. If the reneging persists until this RTO then, as before, we clear the SACK scoreboard and enter CA_Loss. A 10ms delay tolerates a receiver sending such a stream of ACKs at 56Kbit/sec. And to allow for receivers with slower or more congested paths, we wait for at least RTT/2. We validated the resulting max(RTT/2, 10ms) delay formula with a mix of North American and South American Google web server traffic, and found that for ACKs displaying transient reneging: (1) 90% of inter-ACK delays were less than 10ms (2) 99% of inter-ACK delays were less than RTT/2 In tests on Google web servers this commit reduced reneging events by 75%-90% (as measured by the TcpExtTCPSACKReneging counter), without any measurable impact on latency for user HTTP and SPDY requests. Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-08-05 07:12:29 +08:00
tcp_enter_loss(sk);
tcp: implement rb-tree based retransmit queue Using a linear list to store all skbs in write queue has been okay for quite a while : O(N) is not too bad when N < 500. Things get messy when N is the order of 100,000 : Modern TCP stacks want 10Gbit+ of throughput even with 200 ms RTT flows. 40 ns per cache line miss means a full scan can use 4 ms, blowing away CPU caches. SACK processing often can use various hints to avoid parsing whole retransmit queue. But with high packet losses and/or high reordering, hints no longer work. Sender has to process thousands of unfriendly SACK, accumulating a huge socket backlog, burning a cpu and massively dropping packets. Using an rb-tree for retransmit queue has been avoided for years because it added complexity and overhead, but now is the time to be more resistant and say no to quadratic behavior. 1) RTX queue is no longer part of the write queue : already sent skbs are stored in one rb-tree. 2) Since reaching the head of write queue no longer needs sk->sk_send_head, we added an union of sk_send_head and tcp_rtx_queue Tested: On receiver : netem on ingress : delay 150ms 200us loss 1 GRO disabled to force stress and SACK storms. for f in `seq 1 10` do ./netperf -H lpaa6 -l30 -- -K bbr -o THROUGHPUT|tail -1 done | awk '{print $0} {sum += $0} END {printf "%7u\n",sum}' Before patch : 323.87 351.48 339.59 338.62 306.72 204.07 304.93 291.88 202.47 176.88 2840 After patch: 1700.83 2207.98 2070.17 1544.26 2114.76 2124.89 1693.14 1080.91 2216.82 1299.94 18053 Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-06 13:21:27 +08:00
tcp_retransmit_skb(sk, tcp_rtx_queue_head(sk), 1);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
__sk_dst_reset(sk);
goto out_reset_timer;
}
if (tcp_write_timeout(sk))
goto out;
[NET]: Introduce inet_connection_sock This creates struct inet_connection_sock, moving members out of struct tcp_sock that are shareable with other INET connection oriented protocols, such as DCCP, that in my private tree already uses most of these members. The functions that operate on these members were renamed, using a inet_csk_ prefix while not being moved yet to a new file, so as to ease the review of these changes. Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-10 11:10:42 +08:00
if (icsk->icsk_retransmits == 0) {
tcp: de-bloat a bit with factoring NET_INC_STATS_BH out There are some places in TCP that select one MIB index to bump snmp statistics like this: if (<something>) NET_INC_STATS_BH(<some_id>); else if (<something_else>) NET_INC_STATS_BH(<some_other_id>); ... else NET_INC_STATS_BH(<default_id>); or in a more tricky but still similar way. On the other hand, this NET_INC_STATS_BH is a camouflaged increment of percpu variable, which is not that small. Factoring those cases out de-bloats 235 bytes on non-preemptible i386 config and drives parts of the code into 80 columns. add/remove: 0/0 grow/shrink: 0/7 up/down: 0/-235 (-235) function old new delta tcp_fastretrans_alert 1437 1424 -13 tcp_dsack_set 137 124 -13 tcp_xmit_retransmit_queue 690 676 -14 tcp_try_undo_recovery 283 265 -18 tcp_sacktag_write_queue 1550 1515 -35 tcp_update_reordering 162 106 -56 tcp_retransmit_timer 990 904 -86 Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-03 16:05:41 +08:00
int mib_idx;
tcp: use correct counters in CA_CWR state too As CWR is stronger than CA_Disorder state, we can miscount SACK/Reno failure into other timeouts. Not a bad problem as it can happen only due to ECN, FRTO detecting spurious RTO or xmit error which are the only callers of tcp_enter_cwr. And even then losses and RTO must still follow thereafter to actually end up into the relevant code paths. Compile tested. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-10-14 09:52:09 +08:00
if (icsk->icsk_ca_state == TCP_CA_Recovery) {
tcp: cleanup ca_state mess in tcp_timer Redundant checks made indentation impossible to follow. However, it might be useful to make this ca_state+is_sack indexed array. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-02-28 12:44:34 +08:00
if (tcp_is_sack(tp))
mib_idx = LINUX_MIB_TCPSACKRECOVERYFAIL;
else
mib_idx = LINUX_MIB_TCPRENORECOVERYFAIL;
[ICSK]: Move TCP congestion avoidance members to icsk This changeset basically moves tcp_sk()->{ca_ops,ca_state,etc} to inet_csk(), minimal renaming/moving done in this changeset to ease review. Most of it is just changes of struct tcp_sock * to struct sock * parameters. With this we move to a state closer to two interesting goals: 1. Generalisation of net/ipv4/tcp_diag.c, becoming inet_diag.c, being used for any INET transport protocol that has struct inet_hashinfo and are derived from struct inet_connection_sock. Keeps the userspace API, that will just not display DCCP sockets, while newer versions of tools can support DCCP. 2. INET generic transport pluggable Congestion Avoidance infrastructure, using the current TCP CA infrastructure with DCCP. Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-10 15:03:31 +08:00
} else if (icsk->icsk_ca_state == TCP_CA_Loss) {
tcp: de-bloat a bit with factoring NET_INC_STATS_BH out There are some places in TCP that select one MIB index to bump snmp statistics like this: if (<something>) NET_INC_STATS_BH(<some_id>); else if (<something_else>) NET_INC_STATS_BH(<some_other_id>); ... else NET_INC_STATS_BH(<default_id>); or in a more tricky but still similar way. On the other hand, this NET_INC_STATS_BH is a camouflaged increment of percpu variable, which is not that small. Factoring those cases out de-bloats 235 bytes on non-preemptible i386 config and drives parts of the code into 80 columns. add/remove: 0/0 grow/shrink: 0/7 up/down: 0/-235 (-235) function old new delta tcp_fastretrans_alert 1437 1424 -13 tcp_dsack_set 137 124 -13 tcp_xmit_retransmit_queue 690 676 -14 tcp_try_undo_recovery 283 265 -18 tcp_sacktag_write_queue 1550 1515 -35 tcp_update_reordering 162 106 -56 tcp_retransmit_timer 990 904 -86 Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-03 16:05:41 +08:00
mib_idx = LINUX_MIB_TCPLOSSFAILURES;
tcp: use correct counters in CA_CWR state too As CWR is stronger than CA_Disorder state, we can miscount SACK/Reno failure into other timeouts. Not a bad problem as it can happen only due to ECN, FRTO detecting spurious RTO or xmit error which are the only callers of tcp_enter_cwr. And even then losses and RTO must still follow thereafter to actually end up into the relevant code paths. Compile tested. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-10-14 09:52:09 +08:00
} else if ((icsk->icsk_ca_state == TCP_CA_Disorder) ||
tp->sacked_out) {
if (tcp_is_sack(tp))
mib_idx = LINUX_MIB_TCPSACKFAILURES;
else
mib_idx = LINUX_MIB_TCPRENOFAILURES;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
} else {
tcp: de-bloat a bit with factoring NET_INC_STATS_BH out There are some places in TCP that select one MIB index to bump snmp statistics like this: if (<something>) NET_INC_STATS_BH(<some_id>); else if (<something_else>) NET_INC_STATS_BH(<some_other_id>); ... else NET_INC_STATS_BH(<default_id>); or in a more tricky but still similar way. On the other hand, this NET_INC_STATS_BH is a camouflaged increment of percpu variable, which is not that small. Factoring those cases out de-bloats 235 bytes on non-preemptible i386 config and drives parts of the code into 80 columns. add/remove: 0/0 grow/shrink: 0/7 up/down: 0/-235 (-235) function old new delta tcp_fastretrans_alert 1437 1424 -13 tcp_dsack_set 137 124 -13 tcp_xmit_retransmit_queue 690 676 -14 tcp_try_undo_recovery 283 265 -18 tcp_sacktag_write_queue 1550 1515 -35 tcp_update_reordering 162 106 -56 tcp_retransmit_timer 990 904 -86 Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-03 16:05:41 +08:00
mib_idx = LINUX_MIB_TCPTIMEOUTS;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
}
net: rename NET_{ADD|INC}_STATS_BH() Rename NET_INC_STATS_BH() to __NET_INC_STATS() and NET_ADD_STATS_BH() to __NET_ADD_STATS() Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-28 07:44:39 +08:00
__NET_INC_STATS(sock_net(sk), mib_idx);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
}
tcp: reduce spurious retransmits due to transient SACK reneging This commit reduces spurious retransmits due to apparent SACK reneging by only reacting to SACK reneging that persists for a short delay. When a sequence space hole at snd_una is filled, some TCP receivers send a series of ACKs as they apparently scan their out-of-order queue and cumulatively ACK all the packets that have now been consecutiveyly received. This is essentially misbehavior B in "Misbehaviors in TCP SACK generation" ACM SIGCOMM Computer Communication Review, April 2011, so we suspect that this is from several common OSes (Windows 2000, Windows Server 2003, Windows XP). However, this issue has also been seen in other cases, e.g. the netdev thread "TCP being hoodwinked into spurious retransmissions by lack of timestamps?" from March 2014, where the receiver was thought to be a BSD box. Since snd_una would temporarily be adjacent to a previously SACKed range in these scenarios, this receiver behavior triggered the Linux SACK reneging code path in the sender. This led the sender to clear the SACK scoreboard, enter CA_Loss, and spuriously retransmit (potentially) every packet from the entire write queue at line rate just a few milliseconds before the ACK for each packet arrives at the sender. To avoid such situations, now when a sender sees apparent reneging it does not yet retransmit, but rather adjusts the RTO timer to give the receiver a little time (max(RTT/2, 10ms)) to send us some more ACKs that will restore sanity to the SACK scoreboard. If the reneging persists until this RTO then, as before, we clear the SACK scoreboard and enter CA_Loss. A 10ms delay tolerates a receiver sending such a stream of ACKs at 56Kbit/sec. And to allow for receivers with slower or more congested paths, we wait for at least RTT/2. We validated the resulting max(RTT/2, 10ms) delay formula with a mix of North American and South American Google web server traffic, and found that for ACKs displaying transient reneging: (1) 90% of inter-ACK delays were less than 10ms (2) 99% of inter-ACK delays were less than RTT/2 In tests on Google web servers this commit reduced reneging events by 75%-90% (as measured by the TcpExtTCPSACKReneging counter), without any measurable impact on latency for user HTTP and SPDY requests. Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-08-05 07:12:29 +08:00
tcp_enter_loss(sk);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
tcp: implement rb-tree based retransmit queue Using a linear list to store all skbs in write queue has been okay for quite a while : O(N) is not too bad when N < 500. Things get messy when N is the order of 100,000 : Modern TCP stacks want 10Gbit+ of throughput even with 200 ms RTT flows. 40 ns per cache line miss means a full scan can use 4 ms, blowing away CPU caches. SACK processing often can use various hints to avoid parsing whole retransmit queue. But with high packet losses and/or high reordering, hints no longer work. Sender has to process thousands of unfriendly SACK, accumulating a huge socket backlog, burning a cpu and massively dropping packets. Using an rb-tree for retransmit queue has been avoided for years because it added complexity and overhead, but now is the time to be more resistant and say no to quadratic behavior. 1) RTX queue is no longer part of the write queue : already sent skbs are stored in one rb-tree. 2) Since reaching the head of write queue no longer needs sk->sk_send_head, we added an union of sk_send_head and tcp_rtx_queue Tested: On receiver : netem on ingress : delay 150ms 200us loss 1 GRO disabled to force stress and SACK storms. for f in `seq 1 10` do ./netperf -H lpaa6 -l30 -- -K bbr -o THROUGHPUT|tail -1 done | awk '{print $0} {sum += $0} END {printf "%7u\n",sum}' Before patch : 323.87 351.48 339.59 338.62 306.72 204.07 304.93 291.88 202.47 176.88 2840 After patch: 1700.83 2207.98 2070.17 1544.26 2114.76 2124.89 1693.14 1080.91 2216.82 1299.94 18053 Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-06 13:21:27 +08:00
if (tcp_retransmit_skb(sk, tcp_rtx_queue_head(sk), 1) > 0) {
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
/* Retransmission failed because of local congestion,
* do not backoff.
*/
[NET]: Introduce inet_connection_sock This creates struct inet_connection_sock, moving members out of struct tcp_sock that are shareable with other INET connection oriented protocols, such as DCCP, that in my private tree already uses most of these members. The functions that operate on these members were renamed, using a inet_csk_ prefix while not being moved yet to a new file, so as to ease the review of these changes. Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-10 11:10:42 +08:00
if (!icsk->icsk_retransmits)
icsk->icsk_retransmits = 1;
inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
[NET]: Just move the inet_connection_sock function from tcp sources Completing the previous changeset, this also generalises tcp_v4_synq_add, renaming it to inet_csk_reqsk_queue_hash_add, already geing used in the DCCP tree, which I plan to merge RSN. Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-10 11:11:08 +08:00
min(icsk->icsk_rto, TCP_RESOURCE_PROBE_INTERVAL),
TCP_RTO_MAX);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
goto out;
}
/* Increase the timeout each time we retransmit. Note that
* we do not increase the rtt estimate. rto is initialized
* from rtt, but increases here. Jacobson (SIGCOMM 88) suggests
* that doubling rto each time is the least we can get away with.
* In KA9Q, Karn uses this for the first few times, and then
* goes to quadratic. netBSD doubles, but only goes up to *64,
* and clamps at 1 to 64 sec afterwards. Note that 120 sec is
* defined in the protocol as the maximum possible RTT. I guess
* we'll have to use something other than TCP to talk to the
* University of Mars.
*
* PAWS allows us longer timeouts and large windows, so once
* implemented ftp to mars will work nicely. We will have to fix
* the 120 second clamps though!
*/
[NET]: Introduce inet_connection_sock This creates struct inet_connection_sock, moving members out of struct tcp_sock that are shareable with other INET connection oriented protocols, such as DCCP, that in my private tree already uses most of these members. The functions that operate on these members were renamed, using a inet_csk_ prefix while not being moved yet to a new file, so as to ease the review of these changes. Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-10 11:10:42 +08:00
icsk->icsk_backoff++;
icsk->icsk_retransmits++;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
out_reset_timer:
net: TCP thin linear timeouts This patch will make TCP use only linear timeouts if the stream is thin. This will help to avoid the very high latencies that thin stream suffer because of exponential backoff. This mechanism is only active if enabled by iocontrol or syscontrol and the stream is identified as thin. A maximum of 6 linear timeouts is tried before exponential backoff is resumed. Signed-off-by: Andreas Petlund <apetlund@simula.no> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-02-18 10:47:01 +08:00
/* If stream is thin, use linear timeouts. Since 'icsk_backoff' is
* used to reset timer, set to 0. Recalculate 'icsk_rto' as this
* might be increased if the stream oscillates between thin and thick,
* thus the old value might already be too high compared to the value
* set by 'tcp_set_rto' in tcp_input.c which resets the rto without
* backoff. Limit to TCP_THIN_LINEAR_RETRIES before initiating
* exponential backoff behaviour to avoid continue hammering
* linear-timeout retransmissions into a black hole
*/
if (sk->sk_state == TCP_ESTABLISHED &&
tcp: Namespace-ify sysctl_tcp_thin_linear_timeouts Note that sysctl_tcp_thin_dupack was not used, I deleted it. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-27 12:54:58 +08:00
(tp->thin_lto || net->ipv4.sysctl_tcp_thin_linear_timeouts) &&
net: TCP thin linear timeouts This patch will make TCP use only linear timeouts if the stream is thin. This will help to avoid the very high latencies that thin stream suffer because of exponential backoff. This mechanism is only active if enabled by iocontrol or syscontrol and the stream is identified as thin. A maximum of 6 linear timeouts is tried before exponential backoff is resumed. Signed-off-by: Andreas Petlund <apetlund@simula.no> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-02-18 10:47:01 +08:00
tcp_stream_is_thin(tp) &&
icsk->icsk_retransmits <= TCP_THIN_LINEAR_RETRIES) {
icsk->icsk_backoff = 0;
icsk->icsk_rto = min(__tcp_set_rto(tp), TCP_RTO_MAX);
} else {
/* Use normal (exponential) backoff */
icsk->icsk_rto = min(icsk->icsk_rto << 1, TCP_RTO_MAX);
}
[NET]: Just move the inet_connection_sock function from tcp sources Completing the previous changeset, this also generalises tcp_v4_synq_add, renaming it to inet_csk_reqsk_queue_hash_add, already geing used in the DCCP tree, which I plan to merge RSN. Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-10 11:11:08 +08:00
inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, icsk->icsk_rto, TCP_RTO_MAX);
tcp: fix TCP_SYNCNT flakes After the mentioned commit, some of our packetdrill tests became flaky. TCP_SYNCNT socket option can limit the number of SYN retransmits. retransmits_timed_out() has to compare times computations based on local_clock() while timers are based on jiffies. With NTP adjustments and roundings we can observe 999 ms delay for 1000 ms timers. We end up sending one extra SYN packet. Gimmick added in commit 6fa12c850314 ("Revert Backoff [v3]: Calculate TCP's connection close threshold as a time value") makes no real sense for TCP_SYN_SENT sockets where no RTO backoff can happen at all. Lets use a simpler logic for TCP_SYN_SENT sockets and remove @syn_set parameter from retransmits_timed_out() Fixes: 9a568de4818d ("tcp: switch TCP TS option (RFC 7323) to 1ms clock") Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-24 03:38:35 +08:00
if (retransmits_timed_out(sk, net->ipv4.sysctl_tcp_retries1 + 1, 0))
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
__sk_dst_reset(sk);
out:;
}
tcp_timer.c: Add kernel-doc function descriptions This adds kernel-doc style descriptions for 6 functions and fixes 1 typo. Signed-off-by: Richard Sailer <richard@weltraumpflege.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-07-16 10:04:34 +08:00
/* Called with bottom-half processing disabled.
Called by tcp_write_timer() */
tcp: improve latencies of timer triggered events Modern TCP stack highly depends on tcp_write_timer() having a small latency, but current implementation doesn't exactly meet the expectations. When a timer fires but finds the socket is owned by the user, it rearms itself for an additional delay hoping next run will be more successful. tcp_write_timer() for example uses a 50ms delay for next try, and it defeats many attempts to get predictable TCP behavior in term of latencies. Use the recently introduced tcp_release_cb(), so that the user owning the socket will call various handlers right before socket release. This will permit us to post a followup patch to address the tcp_tso_should_defer() syndrome (some deferred packets have to wait RTO timer to be transmitted, while cwnd should allow us to send them sooner) Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Tom Herbert <therbert@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Nandita Dukkipati <nanditad@google.com> Cc: H.K. Jerry Chu <hkchu@google.com> Cc: John Heffner <johnwheffner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-07-20 13:45:50 +08:00
void tcp_write_timer_handler(struct sock *sk)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
{
[NET]: Introduce inet_connection_sock This creates struct inet_connection_sock, moving members out of struct tcp_sock that are shareable with other INET connection oriented protocols, such as DCCP, that in my private tree already uses most of these members. The functions that operate on these members were renamed, using a inet_csk_ prefix while not being moved yet to a new file, so as to ease the review of these changes. Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-10 11:10:42 +08:00
struct inet_connection_sock *icsk = inet_csk(sk);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
int event;
tcp: fix various issues for sockets morphing to listen state Dmitry Vyukov reported a divide by 0 triggered by syzkaller, exploiting tcp_disconnect() path that was never really considered and/or used before syzkaller ;) I was not able to reproduce the bug, but it seems issues here are the three possible actions that assumed they would never trigger on a listener. 1) tcp_write_timer_handler 2) tcp_delack_timer_handler 3) MTU reduction Only IPv6 MTU reduction was properly testing TCP_CLOSE and TCP_LISTEN states from tcp_v6_mtu_reduced() Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-03-04 06:08:21 +08:00
if (((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)) ||
!icsk->icsk_pending)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
goto out;
[NET]: Introduce inet_connection_sock This creates struct inet_connection_sock, moving members out of struct tcp_sock that are shareable with other INET connection oriented protocols, such as DCCP, that in my private tree already uses most of these members. The functions that operate on these members were renamed, using a inet_csk_ prefix while not being moved yet to a new file, so as to ease the review of these changes. Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-10 11:10:42 +08:00
if (time_after(icsk->icsk_timeout, jiffies)) {
sk_reset_timer(sk, &icsk->icsk_retransmit_timer, icsk->icsk_timeout);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
goto out;
}
tcp: switch TCP TS option (RFC 7323) to 1ms clock TCP Timestamps option is defined in RFC 7323 Traditionally on linux, it has been tied to the internal 'jiffies' variable, because it had been a cheap and good enough generator. For TCP flows on the Internet, 1 ms resolution would be much better than 4ms or 10ms (HZ=250 or HZ=100 respectively) For TCP flows in the DC, Google has used usec resolution for more than two years with great success [1] Receive size autotuning (DRS) is indeed more precise and converges faster to optimal window size. This patch converts tp->tcp_mstamp to a plain u64 value storing a 1 usec TCP clock. This choice will allow us to upstream the 1 usec TS option as discussed in IETF 97. [1] https://www.ietf.org/proceedings/97/slides/slides-97-tcpm-tcp-options-for-low-latency-00.pdf Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-17 05:00:14 +08:00
tcp_mstamp_refresh(tcp_sk(sk));
[NET]: Introduce inet_connection_sock This creates struct inet_connection_sock, moving members out of struct tcp_sock that are shareable with other INET connection oriented protocols, such as DCCP, that in my private tree already uses most of these members. The functions that operate on these members were renamed, using a inet_csk_ prefix while not being moved yet to a new file, so as to ease the review of these changes. Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-10 11:10:42 +08:00
event = icsk->icsk_pending;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
switch (event) {
tcp: add reordering timer in RACK loss detection This patch makes RACK install a reordering timer when it suspects some packets might be lost, but wants to delay the decision a little bit to accomodate reordering. It does not create a new timer but instead repurposes the existing RTO timer, because both are meant to retransmit packets. Specifically it arms a timer ICSK_TIME_REO_TIMEOUT when the RACK timing check fails. The wait time is set to RACK.RTT + RACK.reo_wnd - (NOW - Packet.xmit_time) + fudge This translates to expecting a packet (Packet) should take (RACK.RTT + RACK.reo_wnd + fudge) to deliver after it was sent. When there are multiple packets that need a timer, we use one timer with the maximum timeout. Therefore the timer conservatively uses the maximum window to expire N packets by one timeout, instead of N timeouts to expire N packets sent at different times. The fudge factor is 2 jiffies to ensure when the timer fires, all the suspected packets would exceed the deadline and be marked lost by tcp_rack_detect_loss(). It has to be at least 1 jiffy because the clock may tick between calling icsk_reset_xmit_timer(timeout) and actually hang the timer. The next jiffy is to lower-bound the timeout to 2 jiffies when reo_wnd is < 1ms. When the reordering timer fires (tcp_rack_reo_timeout): If we aren't in Recovery we'll enter fast recovery and force fast retransmit. This is very similar to the early retransmit (RFC5827) except RACK is not constrained to only enter recovery for small outstanding flights. Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-01-13 14:11:33 +08:00
case ICSK_TIME_REO_TIMEOUT:
tcp_rack_reo_timeout(sk);
break;
tcp: Tail loss probe (TLP) This patch series implement the Tail loss probe (TLP) algorithm described in http://tools.ietf.org/html/draft-dukkipati-tcpm-tcp-loss-probe-01. The first patch implements the basic algorithm. TLP's goal is to reduce tail latency of short transactions. It achieves this by converting retransmission timeouts (RTOs) occuring due to tail losses (losses at end of transactions) into fast recovery. TLP transmits one packet in two round-trips when a connection is in Open state and isn't receiving any ACKs. The transmitted packet, aka loss probe, can be either new or a retransmission. When there is tail loss, the ACK from a loss probe triggers FACK/early-retransmit based fast recovery, thus avoiding a costly RTO. In the absence of loss, there is no change in the connection state. PTO stands for probe timeout. It is a timer event indicating that an ACK is overdue and triggers a loss probe packet. The PTO value is set to max(2*SRTT, 10ms) and is adjusted to account for delayed ACK timer when there is only one oustanding packet. TLP Algorithm On transmission of new data in Open state: -> packets_out > 1: schedule PTO in max(2*SRTT, 10ms). -> packets_out == 1: schedule PTO in max(2*RTT, 1.5*RTT + 200ms) -> PTO = min(PTO, RTO) Conditions for scheduling PTO: -> Connection is in Open state. -> Connection is either cwnd limited or no new data to send. -> Number of probes per tail loss episode is limited to one. -> Connection is SACK enabled. When PTO fires: new_segment_exists: -> transmit new segment. -> packets_out++. cwnd remains same. no_new_packet: -> retransmit the last segment. Its ACK triggers FACK or early retransmit based recovery. ACK path: -> rearm RTO at start of ACK processing. -> reschedule PTO if need be. In addition, the patch includes a small variation to the Early Retransmit (ER) algorithm, such that ER and TLP together can in principle recover any N-degree of tail loss through fast recovery. TLP is controlled by the same sysctl as ER, tcp_early_retrans sysctl. tcp_early_retrans==0; disables TLP and ER. ==1; enables RFC5827 ER. ==2; delayed ER. ==3; TLP and delayed ER. [DEFAULT] ==4; TLP only. The TLP patch series have been extensively tested on Google Web servers. It is most effective for short Web trasactions, where it reduced RTOs by 15% and improved HTTP response time (average by 6%, 99th percentile by 10%). The transmitted probes account for <0.5% of the overall transmissions. Signed-off-by: Nandita Dukkipati <nanditad@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Acked-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-03-11 18:00:43 +08:00
case ICSK_TIME_LOSS_PROBE:
tcp_send_loss_probe(sk);
break;
[NET]: Introduce inet_connection_sock This creates struct inet_connection_sock, moving members out of struct tcp_sock that are shareable with other INET connection oriented protocols, such as DCCP, that in my private tree already uses most of these members. The functions that operate on these members were renamed, using a inet_csk_ prefix while not being moved yet to a new file, so as to ease the review of these changes. Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-10 11:10:42 +08:00
case ICSK_TIME_RETRANS:
tcp: Tail loss probe (TLP) This patch series implement the Tail loss probe (TLP) algorithm described in http://tools.ietf.org/html/draft-dukkipati-tcpm-tcp-loss-probe-01. The first patch implements the basic algorithm. TLP's goal is to reduce tail latency of short transactions. It achieves this by converting retransmission timeouts (RTOs) occuring due to tail losses (losses at end of transactions) into fast recovery. TLP transmits one packet in two round-trips when a connection is in Open state and isn't receiving any ACKs. The transmitted packet, aka loss probe, can be either new or a retransmission. When there is tail loss, the ACK from a loss probe triggers FACK/early-retransmit based fast recovery, thus avoiding a costly RTO. In the absence of loss, there is no change in the connection state. PTO stands for probe timeout. It is a timer event indicating that an ACK is overdue and triggers a loss probe packet. The PTO value is set to max(2*SRTT, 10ms) and is adjusted to account for delayed ACK timer when there is only one oustanding packet. TLP Algorithm On transmission of new data in Open state: -> packets_out > 1: schedule PTO in max(2*SRTT, 10ms). -> packets_out == 1: schedule PTO in max(2*RTT, 1.5*RTT + 200ms) -> PTO = min(PTO, RTO) Conditions for scheduling PTO: -> Connection is in Open state. -> Connection is either cwnd limited or no new data to send. -> Number of probes per tail loss episode is limited to one. -> Connection is SACK enabled. When PTO fires: new_segment_exists: -> transmit new segment. -> packets_out++. cwnd remains same. no_new_packet: -> retransmit the last segment. Its ACK triggers FACK or early retransmit based recovery. ACK path: -> rearm RTO at start of ACK processing. -> reschedule PTO if need be. In addition, the patch includes a small variation to the Early Retransmit (ER) algorithm, such that ER and TLP together can in principle recover any N-degree of tail loss through fast recovery. TLP is controlled by the same sysctl as ER, tcp_early_retrans sysctl. tcp_early_retrans==0; disables TLP and ER. ==1; enables RFC5827 ER. ==2; delayed ER. ==3; TLP and delayed ER. [DEFAULT] ==4; TLP only. The TLP patch series have been extensively tested on Google Web servers. It is most effective for short Web trasactions, where it reduced RTOs by 15% and improved HTTP response time (average by 6%, 99th percentile by 10%). The transmitted probes account for <0.5% of the overall transmissions. Signed-off-by: Nandita Dukkipati <nanditad@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Acked-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-03-11 18:00:43 +08:00
icsk->icsk_pending = 0;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
tcp_retransmit_timer(sk);
break;
[NET]: Introduce inet_connection_sock This creates struct inet_connection_sock, moving members out of struct tcp_sock that are shareable with other INET connection oriented protocols, such as DCCP, that in my private tree already uses most of these members. The functions that operate on these members were renamed, using a inet_csk_ prefix while not being moved yet to a new file, so as to ease the review of these changes. Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-10 11:10:42 +08:00
case ICSK_TIME_PROBE0:
tcp: Tail loss probe (TLP) This patch series implement the Tail loss probe (TLP) algorithm described in http://tools.ietf.org/html/draft-dukkipati-tcpm-tcp-loss-probe-01. The first patch implements the basic algorithm. TLP's goal is to reduce tail latency of short transactions. It achieves this by converting retransmission timeouts (RTOs) occuring due to tail losses (losses at end of transactions) into fast recovery. TLP transmits one packet in two round-trips when a connection is in Open state and isn't receiving any ACKs. The transmitted packet, aka loss probe, can be either new or a retransmission. When there is tail loss, the ACK from a loss probe triggers FACK/early-retransmit based fast recovery, thus avoiding a costly RTO. In the absence of loss, there is no change in the connection state. PTO stands for probe timeout. It is a timer event indicating that an ACK is overdue and triggers a loss probe packet. The PTO value is set to max(2*SRTT, 10ms) and is adjusted to account for delayed ACK timer when there is only one oustanding packet. TLP Algorithm On transmission of new data in Open state: -> packets_out > 1: schedule PTO in max(2*SRTT, 10ms). -> packets_out == 1: schedule PTO in max(2*RTT, 1.5*RTT + 200ms) -> PTO = min(PTO, RTO) Conditions for scheduling PTO: -> Connection is in Open state. -> Connection is either cwnd limited or no new data to send. -> Number of probes per tail loss episode is limited to one. -> Connection is SACK enabled. When PTO fires: new_segment_exists: -> transmit new segment. -> packets_out++. cwnd remains same. no_new_packet: -> retransmit the last segment. Its ACK triggers FACK or early retransmit based recovery. ACK path: -> rearm RTO at start of ACK processing. -> reschedule PTO if need be. In addition, the patch includes a small variation to the Early Retransmit (ER) algorithm, such that ER and TLP together can in principle recover any N-degree of tail loss through fast recovery. TLP is controlled by the same sysctl as ER, tcp_early_retrans sysctl. tcp_early_retrans==0; disables TLP and ER. ==1; enables RFC5827 ER. ==2; delayed ER. ==3; TLP and delayed ER. [DEFAULT] ==4; TLP only. The TLP patch series have been extensively tested on Google Web servers. It is most effective for short Web trasactions, where it reduced RTOs by 15% and improved HTTP response time (average by 6%, 99th percentile by 10%). The transmitted probes account for <0.5% of the overall transmissions. Signed-off-by: Nandita Dukkipati <nanditad@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Acked-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-03-11 18:00:43 +08:00
icsk->icsk_pending = 0;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
tcp_probe_timer(sk);
break;
}
out:
[NET] CORE: Introducing new memory accounting interface. This patch introduces new memory accounting functions for each network protocol. Most of them are renamed from memory accounting functions for stream protocols. At the same time, some stream memory accounting functions are removed since other functions do same thing. Renaming: sk_stream_free_skb() -> sk_wmem_free_skb() __sk_stream_mem_reclaim() -> __sk_mem_reclaim() sk_stream_mem_reclaim() -> sk_mem_reclaim() sk_stream_mem_schedule -> __sk_mem_schedule() sk_stream_pages() -> sk_mem_pages() sk_stream_rmem_schedule() -> sk_rmem_schedule() sk_stream_wmem_schedule() -> sk_wmem_schedule() sk_charge_skb() -> sk_mem_charge() Removeing sk_stream_rfree(): consolidates into sock_rfree() sk_stream_set_owner_r(): consolidates into skb_set_owner_r() sk_stream_mem_schedule() The following functions are added. sk_has_account(): check if the protocol supports accounting sk_mem_uncharge(): do the opposite of sk_mem_charge() In addition, to achieve consolidation, updating sk_wmem_queued is removed from sk_mem_charge(). Next, to consolidate memory accounting functions, this patch adds memory accounting calls to network core functions. Moreover, present memory accounting call is renamed to new accounting call. Finally we replace present memory accounting calls with new interface in TCP and SCTP. Signed-off-by: Takahiro Yasui <tyasui@redhat.com> Signed-off-by: Hideo Aoki <haoki@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-12-31 16:11:19 +08:00
sk_mem_reclaim(sk);
tcp: improve latencies of timer triggered events Modern TCP stack highly depends on tcp_write_timer() having a small latency, but current implementation doesn't exactly meet the expectations. When a timer fires but finds the socket is owned by the user, it rearms itself for an additional delay hoping next run will be more successful. tcp_write_timer() for example uses a 50ms delay for next try, and it defeats many attempts to get predictable TCP behavior in term of latencies. Use the recently introduced tcp_release_cb(), so that the user owning the socket will call various handlers right before socket release. This will permit us to post a followup patch to address the tcp_tso_should_defer() syndrome (some deferred packets have to wait RTO timer to be transmitted, while cwnd should allow us to send them sooner) Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Tom Herbert <therbert@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Nandita Dukkipati <nanditad@google.com> Cc: H.K. Jerry Chu <hkchu@google.com> Cc: John Heffner <johnwheffner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-07-20 13:45:50 +08:00
}
inet/connection_sock: Convert timers to use timer_setup() In preparation for unconditionally passing the struct timer_list pointer to all timer callbacks, switch to using the new timer_setup() and from_timer() to pass the timer pointer explicitly. Cc: "David S. Miller" <davem@davemloft.net> Cc: Gerrit Renker <gerrit@erg.abdn.ac.uk> Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org> Cc: netdev@vger.kernel.org Cc: dccp@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-17 08:29:19 +08:00
static void tcp_write_timer(struct timer_list *t)
tcp: improve latencies of timer triggered events Modern TCP stack highly depends on tcp_write_timer() having a small latency, but current implementation doesn't exactly meet the expectations. When a timer fires but finds the socket is owned by the user, it rearms itself for an additional delay hoping next run will be more successful. tcp_write_timer() for example uses a 50ms delay for next try, and it defeats many attempts to get predictable TCP behavior in term of latencies. Use the recently introduced tcp_release_cb(), so that the user owning the socket will call various handlers right before socket release. This will permit us to post a followup patch to address the tcp_tso_should_defer() syndrome (some deferred packets have to wait RTO timer to be transmitted, while cwnd should allow us to send them sooner) Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Tom Herbert <therbert@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Nandita Dukkipati <nanditad@google.com> Cc: H.K. Jerry Chu <hkchu@google.com> Cc: John Heffner <johnwheffner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-07-20 13:45:50 +08:00
{
inet/connection_sock: Convert timers to use timer_setup() In preparation for unconditionally passing the struct timer_list pointer to all timer callbacks, switch to using the new timer_setup() and from_timer() to pass the timer pointer explicitly. Cc: "David S. Miller" <davem@davemloft.net> Cc: Gerrit Renker <gerrit@erg.abdn.ac.uk> Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org> Cc: netdev@vger.kernel.org Cc: dccp@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-17 08:29:19 +08:00
struct inet_connection_sock *icsk =
from_timer(icsk, t, icsk_retransmit_timer);
struct sock *sk = &icsk->icsk_inet.sk;
tcp: improve latencies of timer triggered events Modern TCP stack highly depends on tcp_write_timer() having a small latency, but current implementation doesn't exactly meet the expectations. When a timer fires but finds the socket is owned by the user, it rearms itself for an additional delay hoping next run will be more successful. tcp_write_timer() for example uses a 50ms delay for next try, and it defeats many attempts to get predictable TCP behavior in term of latencies. Use the recently introduced tcp_release_cb(), so that the user owning the socket will call various handlers right before socket release. This will permit us to post a followup patch to address the tcp_tso_should_defer() syndrome (some deferred packets have to wait RTO timer to be transmitted, while cwnd should allow us to send them sooner) Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Tom Herbert <therbert@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Nandita Dukkipati <nanditad@google.com> Cc: H.K. Jerry Chu <hkchu@google.com> Cc: John Heffner <johnwheffner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-07-20 13:45:50 +08:00
bh_lock_sock(sk);
if (!sock_owned_by_user(sk)) {
tcp_write_timer_handler(sk);
} else {
tcp_timer.c: Add kernel-doc function descriptions This adds kernel-doc style descriptions for 6 functions and fixes 1 typo. Signed-off-by: Richard Sailer <richard@weltraumpflege.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-07-16 10:04:34 +08:00
/* delegate our work to tcp_release_cb() */
tcp: tsq: move tsq_flags close to sk_wmem_alloc tsq_flags being in the same cache line than sk_wmem_alloc makes a lot of sense. Both fields are changed from tcp_wfree() and more generally by various TSQ related functions. Prior patch made room in struct sock and added sk_tsq_flags, this patch deletes tsq_flags from struct tcp_sock. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-12-04 03:14:57 +08:00
if (!test_and_set_bit(TCP_WRITE_TIMER_DEFERRED, &sk->sk_tsq_flags))
tcp: fix possible socket refcount problem Commit 6f458dfb40 (tcp: improve latencies of timer triggered events) added bug leading to following trace : [ 2866.131281] IPv4: Attempt to release TCP socket in state 1 ffff880019ec0000 [ 2866.131726] [ 2866.132188] ========================= [ 2866.132281] [ BUG: held lock freed! ] [ 2866.132281] 3.6.0-rc1+ #622 Not tainted [ 2866.132281] ------------------------- [ 2866.132281] kworker/0:1/652 is freeing memory ffff880019ec0000-ffff880019ec0a1f, with a lock still held there! [ 2866.132281] (sk_lock-AF_INET-RPC){+.+...}, at: [<ffffffff81903619>] tcp_sendmsg+0x29/0xcc6 [ 2866.132281] 4 locks held by kworker/0:1/652: [ 2866.132281] #0: (rpciod){.+.+.+}, at: [<ffffffff81083567>] process_one_work+0x1de/0x47f [ 2866.132281] #1: ((&task->u.tk_work)){+.+.+.}, at: [<ffffffff81083567>] process_one_work+0x1de/0x47f [ 2866.132281] #2: (sk_lock-AF_INET-RPC){+.+...}, at: [<ffffffff81903619>] tcp_sendmsg+0x29/0xcc6 [ 2866.132281] #3: (&icsk->icsk_retransmit_timer){+.-...}, at: [<ffffffff81078017>] run_timer_softirq+0x1ad/0x35f [ 2866.132281] [ 2866.132281] stack backtrace: [ 2866.132281] Pid: 652, comm: kworker/0:1 Not tainted 3.6.0-rc1+ #622 [ 2866.132281] Call Trace: [ 2866.132281] <IRQ> [<ffffffff810bc527>] debug_check_no_locks_freed+0x112/0x159 [ 2866.132281] [<ffffffff818a0839>] ? __sk_free+0xfd/0x114 [ 2866.132281] [<ffffffff811549fa>] kmem_cache_free+0x6b/0x13a [ 2866.132281] [<ffffffff818a0839>] __sk_free+0xfd/0x114 [ 2866.132281] [<ffffffff818a08c0>] sk_free+0x1c/0x1e [ 2866.132281] [<ffffffff81911e1c>] tcp_write_timer+0x51/0x56 [ 2866.132281] [<ffffffff81078082>] run_timer_softirq+0x218/0x35f [ 2866.132281] [<ffffffff81078017>] ? run_timer_softirq+0x1ad/0x35f [ 2866.132281] [<ffffffff810f5831>] ? rb_commit+0x58/0x85 [ 2866.132281] [<ffffffff81911dcb>] ? tcp_write_timer_handler+0x148/0x148 [ 2866.132281] [<ffffffff81070bd6>] __do_softirq+0xcb/0x1f9 [ 2866.132281] [<ffffffff81a0a00c>] ? _raw_spin_unlock+0x29/0x2e [ 2866.132281] [<ffffffff81a1227c>] call_softirq+0x1c/0x30 [ 2866.132281] [<ffffffff81039f38>] do_softirq+0x4a/0xa6 [ 2866.132281] [<ffffffff81070f2b>] irq_exit+0x51/0xad [ 2866.132281] [<ffffffff81a129cd>] do_IRQ+0x9d/0xb4 [ 2866.132281] [<ffffffff81a0a3ef>] common_interrupt+0x6f/0x6f [ 2866.132281] <EOI> [<ffffffff8109d006>] ? sched_clock_cpu+0x58/0xd1 [ 2866.132281] [<ffffffff81a0a172>] ? _raw_spin_unlock_irqrestore+0x4c/0x56 [ 2866.132281] [<ffffffff81078692>] mod_timer+0x178/0x1a9 [ 2866.132281] [<ffffffff818a00aa>] sk_reset_timer+0x19/0x26 [ 2866.132281] [<ffffffff8190b2cc>] tcp_rearm_rto+0x99/0xa4 [ 2866.132281] [<ffffffff8190dfba>] tcp_event_new_data_sent+0x6e/0x70 [ 2866.132281] [<ffffffff8190f7ea>] tcp_write_xmit+0x7de/0x8e4 [ 2866.132281] [<ffffffff818a565d>] ? __alloc_skb+0xa0/0x1a1 [ 2866.132281] [<ffffffff8190f952>] __tcp_push_pending_frames+0x2e/0x8a [ 2866.132281] [<ffffffff81904122>] tcp_sendmsg+0xb32/0xcc6 [ 2866.132281] [<ffffffff819229c2>] inet_sendmsg+0xaa/0xd5 [ 2866.132281] [<ffffffff81922918>] ? inet_autobind+0x5f/0x5f [ 2866.132281] [<ffffffff810ee7f1>] ? trace_clock_local+0x9/0xb [ 2866.132281] [<ffffffff8189adab>] sock_sendmsg+0xa3/0xc4 [ 2866.132281] [<ffffffff810f5de6>] ? rb_reserve_next_event+0x26f/0x2d5 [ 2866.132281] [<ffffffff8103e6a9>] ? native_sched_clock+0x29/0x6f [ 2866.132281] [<ffffffff8103e6f8>] ? sched_clock+0x9/0xd [ 2866.132281] [<ffffffff810ee7f1>] ? trace_clock_local+0x9/0xb [ 2866.132281] [<ffffffff8189ae03>] kernel_sendmsg+0x37/0x43 [ 2866.132281] [<ffffffff8199ce49>] xs_send_kvec+0x77/0x80 [ 2866.132281] [<ffffffff8199cec1>] xs_sendpages+0x6f/0x1a0 [ 2866.132281] [<ffffffff8107826d>] ? try_to_del_timer_sync+0x55/0x61 [ 2866.132281] [<ffffffff8199d0d2>] xs_tcp_send_request+0x55/0xf1 [ 2866.132281] [<ffffffff8199bb90>] xprt_transmit+0x89/0x1db [ 2866.132281] [<ffffffff81999bcd>] ? call_connect+0x3c/0x3c [ 2866.132281] [<ffffffff81999d92>] call_transmit+0x1c5/0x20e [ 2866.132281] [<ffffffff819a0d55>] __rpc_execute+0x6f/0x225 [ 2866.132281] [<ffffffff81999bcd>] ? call_connect+0x3c/0x3c [ 2866.132281] [<ffffffff819a0f33>] rpc_async_schedule+0x28/0x34 [ 2866.132281] [<ffffffff810835d6>] process_one_work+0x24d/0x47f [ 2866.132281] [<ffffffff81083567>] ? process_one_work+0x1de/0x47f [ 2866.132281] [<ffffffff819a0f0b>] ? __rpc_execute+0x225/0x225 [ 2866.132281] [<ffffffff81083a6d>] worker_thread+0x236/0x317 [ 2866.132281] [<ffffffff81083837>] ? process_scheduled_works+0x2f/0x2f [ 2866.132281] [<ffffffff8108b7b8>] kthread+0x9a/0xa2 [ 2866.132281] [<ffffffff81a12184>] kernel_thread_helper+0x4/0x10 [ 2866.132281] [<ffffffff81a0a4b0>] ? retint_restore_args+0x13/0x13 [ 2866.132281] [<ffffffff8108b71e>] ? __init_kthread_worker+0x5a/0x5a [ 2866.132281] [<ffffffff81a12180>] ? gs_change+0x13/0x13 [ 2866.308506] IPv4: Attempt to release TCP socket in state 1 ffff880019ec0000 [ 2866.309689] ============================================================================= [ 2866.310254] BUG TCP (Not tainted): Object already free [ 2866.310254] ----------------------------------------------------------------------------- [ 2866.310254] The bug comes from the fact that timer set in sk_reset_timer() can run before we actually do the sock_hold(). socket refcount reaches zero and we free the socket too soon. timer handler is not allowed to reduce socket refcnt if socket is owned by the user, or we need to change sk_reset_timer() implementation. We should take a reference on the socket in case TCP_DELACK_TIMER_DEFERRED or TCP_DELACK_TIMER_DEFERRED bit are set in tsq_flags Also fix a typo in tcp_delack_timer(), where TCP_WRITE_TIMER_DEFERRED was used instead of TCP_DELACK_TIMER_DEFERRED. For consistency, use same socket refcount change for TCP_MTU_REDUCED_DEFERRED, even if not fired from a timer. Reported-by: Fengguang Wu <fengguang.wu@intel.com> Tested-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-08-20 08:22:46 +08:00
sock_hold(sk);
tcp: improve latencies of timer triggered events Modern TCP stack highly depends on tcp_write_timer() having a small latency, but current implementation doesn't exactly meet the expectations. When a timer fires but finds the socket is owned by the user, it rearms itself for an additional delay hoping next run will be more successful. tcp_write_timer() for example uses a 50ms delay for next try, and it defeats many attempts to get predictable TCP behavior in term of latencies. Use the recently introduced tcp_release_cb(), so that the user owning the socket will call various handlers right before socket release. This will permit us to post a followup patch to address the tcp_tso_should_defer() syndrome (some deferred packets have to wait RTO timer to be transmitted, while cwnd should allow us to send them sooner) Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Tom Herbert <therbert@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Nandita Dukkipati <nanditad@google.com> Cc: H.K. Jerry Chu <hkchu@google.com> Cc: John Heffner <johnwheffner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-07-20 13:45:50 +08:00
}
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
bh_unlock_sock(sk);
sock_put(sk);
}
inet: remove sk_listener parameter from syn_ack_timeout() It is not needed, and req->sk_listener points to the listener anyway. request_sock argument can be const. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-23 01:22:19 +08:00
void tcp_syn_ack_timeout(const struct request_sock *req)
tcp: account SYN-ACK timeouts & retransmissions Currently we don't increment SYN-ACK timeouts & retransmissions although we do increment the same stats for SYN. We seem to have lost the SYN-ACK accounting with the introduction of tcp_syn_recv_timer (commit 2248761e in the netdev-vger-cvs tree). This patch fixes this issue. In the process we also rename the v4/v6 syn/ack retransmit functions for clarity. We also add a new request_socket operations (syn_ack_timeout) so we can keep code in inet_connection_sock.c protocol agnostic. Signed-off-by: Octavian Purdila <opurdila@ixiacom.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-01-18 11:09:39 +08:00
{
inet: remove sk_listener parameter from syn_ack_timeout() It is not needed, and req->sk_listener points to the listener anyway. request_sock argument can be const. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-23 01:22:19 +08:00
struct net *net = read_pnet(&inet_rsk(req)->ireq_net);
net: rename NET_{ADD|INC}_STATS_BH() Rename NET_INC_STATS_BH() to __NET_INC_STATS() and NET_ADD_STATS_BH() to __NET_ADD_STATS() Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-28 07:44:39 +08:00
__NET_INC_STATS(net, LINUX_MIB_TCPTIMEOUTS);
tcp: account SYN-ACK timeouts & retransmissions Currently we don't increment SYN-ACK timeouts & retransmissions although we do increment the same stats for SYN. We seem to have lost the SYN-ACK accounting with the introduction of tcp_syn_recv_timer (commit 2248761e in the netdev-vger-cvs tree). This patch fixes this issue. In the process we also rename the v4/v6 syn/ack retransmit functions for clarity. We also add a new request_socket operations (syn_ack_timeout) so we can keep code in inet_connection_sock.c protocol agnostic. Signed-off-by: Octavian Purdila <opurdila@ixiacom.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-01-18 11:09:39 +08:00
}
EXPORT_SYMBOL(tcp_syn_ack_timeout);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
void tcp_set_keepalive(struct sock *sk, int val)
{
if ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))
return;
if (val && !sock_flag(sk, SOCK_KEEPOPEN))
[NET]: Introduce inet_connection_sock This creates struct inet_connection_sock, moving members out of struct tcp_sock that are shareable with other INET connection oriented protocols, such as DCCP, that in my private tree already uses most of these members. The functions that operate on these members were renamed, using a inet_csk_ prefix while not being moved yet to a new file, so as to ease the review of these changes. Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-10 11:10:42 +08:00
inet_csk_reset_keepalive_timer(sk, keepalive_time_when(tcp_sk(sk)));
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
else if (!val)
[NET]: Introduce inet_connection_sock This creates struct inet_connection_sock, moving members out of struct tcp_sock that are shareable with other INET connection oriented protocols, such as DCCP, that in my private tree already uses most of these members. The functions that operate on these members were renamed, using a inet_csk_ prefix while not being moved yet to a new file, so as to ease the review of these changes. Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-10 11:10:42 +08:00
inet_csk_delete_keepalive_timer(sk);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
}
net: introduce keepalive function in struct proto Direct call of tcp_set_keepalive() function from protocol-agnostic sock_setsockopt() function in net/core/sock.c violates network layering. And newly introduced protocol (SMC-R) will need its own keepalive function. Therefore, add "keepalive" function pointer to "struct proto", and call it from sock_setsockopt() via this pointer. Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com> Reviewed-by: Utz Bacher <utz.bacher@de.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-01-09 23:55:12 +08:00
EXPORT_SYMBOL_GPL(tcp_set_keepalive);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
inet/connection_sock: Convert timers to use timer_setup() In preparation for unconditionally passing the struct timer_list pointer to all timer callbacks, switch to using the new timer_setup() and from_timer() to pass the timer pointer explicitly. Cc: "David S. Miller" <davem@davemloft.net> Cc: Gerrit Renker <gerrit@erg.abdn.ac.uk> Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org> Cc: netdev@vger.kernel.org Cc: dccp@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-17 08:29:19 +08:00
static void tcp_keepalive_timer (struct timer_list *t)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
{
inet/connection_sock: Convert timers to use timer_setup() In preparation for unconditionally passing the struct timer_list pointer to all timer callbacks, switch to using the new timer_setup() and from_timer() to pass the timer pointer explicitly. Cc: "David S. Miller" <davem@davemloft.net> Cc: Gerrit Renker <gerrit@erg.abdn.ac.uk> Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org> Cc: netdev@vger.kernel.org Cc: dccp@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-17 08:29:19 +08:00
struct sock *sk = from_timer(sk, t, sk_timer);
[ICSK]: Move TCP congestion avoidance members to icsk This changeset basically moves tcp_sk()->{ca_ops,ca_state,etc} to inet_csk(), minimal renaming/moving done in this changeset to ease review. Most of it is just changes of struct tcp_sock * to struct sock * parameters. With this we move to a state closer to two interesting goals: 1. Generalisation of net/ipv4/tcp_diag.c, becoming inet_diag.c, being used for any INET transport protocol that has struct inet_hashinfo and are derived from struct inet_connection_sock. Keeps the userspace API, that will just not display DCCP sockets, while newer versions of tools can support DCCP. 2. INET generic transport pluggable Congestion Avoidance infrastructure, using the current TCP CA infrastructure with DCCP. Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-10 15:03:31 +08:00
struct inet_connection_sock *icsk = inet_csk(sk);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
struct tcp_sock *tp = tcp_sk(sk);
TCP: avoid to send keepalive probes if receiving data RFC 1122 says the following: ... Keep-alive packets MUST only be sent when no data or acknowledgement packets have been received for the connection within an interval. ... The acknowledgement packet is reseting the keepalive timer but the data packet isn't. This patch fixes it by checking the timestamp of the last received data packet too when the keepalive timer expires. Signed-off-by: Flavio Leitner <fleitner@redhat.com> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Acked-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-04-27 02:33:27 +08:00
u32 elapsed;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
/* Only process if socket is not in use. */
bh_lock_sock(sk);
if (sock_owned_by_user(sk)) {
[NET] IPV4: Fix whitespace errors. Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-02-09 22:24:47 +08:00
/* Try again later. */
[NET]: Introduce inet_connection_sock This creates struct inet_connection_sock, moving members out of struct tcp_sock that are shareable with other INET connection oriented protocols, such as DCCP, that in my private tree already uses most of these members. The functions that operate on these members were renamed, using a inet_csk_ prefix while not being moved yet to a new file, so as to ease the review of these changes. Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-10 11:10:42 +08:00
inet_csk_reset_keepalive_timer (sk, HZ/20);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
goto out;
}
if (sk->sk_state == TCP_LISTEN) {
inet: get rid of central tcp/dccp listener timer One of the major issue for TCP is the SYNACK rtx handling, done by inet_csk_reqsk_queue_prune(), fired by the keepalive timer of a TCP_LISTEN socket. This function runs for awful long times, with socket lock held, meaning that other cpus needing this lock have to spin for hundred of ms. SYNACK are sent in huge bursts, likely to cause severe drops anyway. This model was OK 15 years ago when memory was very tight. We now can afford to have a timer per request sock. Timer invocations no longer need to lock the listener, and can be run from all cpus in parallel. With following patch increasing somaxconn width to 32 bits, I tested a listener with more than 4 million active request sockets, and a steady SYNFLOOD of ~200,000 SYN per second. Host was sending ~830,000 SYNACK per second. This is ~100 times more what we could achieve before this patch. Later, we will get rid of the listener hash and use ehash instead. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-20 10:04:20 +08:00
pr_err("Hmm... keepalive on a LISTEN ???\n");
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
goto out;
}
tcp: refresh tcp_mstamp from timers callbacks Only the retransmit timer currently refreshes tcp_mstamp We should do the same for delayed acks and keepalives. Even if RFC 7323 does not request it, this is consistent to what linux did in the past, when TS values were based on jiffies. Fixes: 385e20706fac ("tcp: use tp->tcp_mstamp in output path") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Soheil Hassas Yeganeh <soheil@google.com> Cc: Mike Maloney <maloney@google.com> Cc: Neal Cardwell <ncardwell@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Acked-by: Mike Maloney <maloney@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-12-13 10:22:52 +08:00
tcp_mstamp_refresh(tp);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
if (sk->sk_state == TCP_FIN_WAIT2 && sock_flag(sk, SOCK_DEAD)) {
if (tp->linger2 >= 0) {
[NET]: Introduce inet_connection_sock This creates struct inet_connection_sock, moving members out of struct tcp_sock that are shareable with other INET connection oriented protocols, such as DCCP, that in my private tree already uses most of these members. The functions that operate on these members were renamed, using a inet_csk_ prefix while not being moved yet to a new file, so as to ease the review of these changes. Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-10 11:10:42 +08:00
const int tmo = tcp_fin_time(sk) - TCP_TIMEWAIT_LEN;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
if (tmo > 0) {
tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
goto out;
}
}
tcp_send_active_reset(sk, GFP_ATOMIC);
goto death;
}
net: fix keepalive code vs TCP_FASTOPEN_CONNECT syzkaller was able to trigger a divide by 0 in TCP stack [1] Issue here is that keepalive timer needs to be updated to not attempt to send a probe if the connection setup was deferred using TCP_FASTOPEN_CONNECT socket option added in linux-4.11 [1] divide error: 0000 [#1] SMP CPU: 18 PID: 0 Comm: swapper/18 Not tainted task: ffff986f62f4b040 ti: ffff986f62fa2000 task.ti: ffff986f62fa2000 RIP: 0010:[<ffffffff8409cc0d>] [<ffffffff8409cc0d>] __tcp_select_window+0x8d/0x160 Call Trace: <IRQ> [<ffffffff8409d951>] tcp_transmit_skb+0x11/0x20 [<ffffffff8409da21>] tcp_xmit_probe_skb+0xc1/0xe0 [<ffffffff840a0ee8>] tcp_write_wakeup+0x68/0x160 [<ffffffff840a151b>] tcp_keepalive_timer+0x17b/0x230 [<ffffffff83b3f799>] call_timer_fn+0x39/0xf0 [<ffffffff83b40797>] run_timer_softirq+0x1d7/0x280 [<ffffffff83a04ddb>] __do_softirq+0xcb/0x257 [<ffffffff83ae03ac>] irq_exit+0x9c/0xb0 [<ffffffff83a04c1a>] smp_apic_timer_interrupt+0x6a/0x80 [<ffffffff83a03eaf>] apic_timer_interrupt+0x7f/0x90 <EOI> [<ffffffff83fed2ea>] ? cpuidle_enter_state+0x13a/0x3b0 [<ffffffff83fed2cd>] ? cpuidle_enter_state+0x11d/0x3b0 Tested: Following packetdrill no longer crashes the kernel `echo 0 >/proc/sys/net/ipv4/tcp_timestamps` // Cache warmup: send a Fast Open cookie request 0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3 +0 fcntl(3, F_SETFL, O_RDWR|O_NONBLOCK) = 0 +0 setsockopt(3, SOL_TCP, TCP_FASTOPEN_CONNECT, [1], 4) = 0 +0 connect(3, ..., ...) = -1 EINPROGRESS (Operation is now in progress) +0 > S 0:0(0) <mss 1460,nop,nop,sackOK,nop,wscale 8,FO,nop,nop> +.01 < S. 123:123(0) ack 1 win 14600 <mss 1460,nop,nop,sackOK,nop,wscale 6,FO abcd1234,nop,nop> +0 > . 1:1(0) ack 1 +0 close(3) = 0 +0 > F. 1:1(0) ack 1 +0 < F. 1:1(0) ack 2 win 92 +0 > . 2:2(0) ack 2 +0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 4 +0 fcntl(4, F_SETFL, O_RDWR|O_NONBLOCK) = 0 +0 setsockopt(4, SOL_TCP, TCP_FASTOPEN_CONNECT, [1], 4) = 0 +0 setsockopt(4, SOL_SOCKET, SO_KEEPALIVE, [1], 4) = 0 +.01 connect(4, ..., ...) = 0 +0 setsockopt(4, SOL_TCP, TCP_KEEPIDLE, [5], 4) = 0 +10 close(4) = 0 `echo 1 >/proc/sys/net/ipv4/tcp_timestamps` Fixes: 19f6d3f3c842 ("net/tcp-fastopen: Add new API support") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Cc: Wei Wang <weiwan@google.com> Cc: Yuchung Cheng <ycheng@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-08-03 14:10:46 +08:00
if (!sock_flag(sk, SOCK_KEEPOPEN) ||
((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_SYN_SENT)))
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
goto out;
elapsed = keepalive_time_when(tp);
/* It is alive without keepalive 8) */
tcp: implement rb-tree based retransmit queue Using a linear list to store all skbs in write queue has been okay for quite a while : O(N) is not too bad when N < 500. Things get messy when N is the order of 100,000 : Modern TCP stacks want 10Gbit+ of throughput even with 200 ms RTT flows. 40 ns per cache line miss means a full scan can use 4 ms, blowing away CPU caches. SACK processing often can use various hints to avoid parsing whole retransmit queue. But with high packet losses and/or high reordering, hints no longer work. Sender has to process thousands of unfriendly SACK, accumulating a huge socket backlog, burning a cpu and massively dropping packets. Using an rb-tree for retransmit queue has been avoided for years because it added complexity and overhead, but now is the time to be more resistant and say no to quadratic behavior. 1) RTX queue is no longer part of the write queue : already sent skbs are stored in one rb-tree. 2) Since reaching the head of write queue no longer needs sk->sk_send_head, we added an union of sk_send_head and tcp_rtx_queue Tested: On receiver : netem on ingress : delay 150ms 200us loss 1 GRO disabled to force stress and SACK storms. for f in `seq 1 10` do ./netperf -H lpaa6 -l30 -- -K bbr -o THROUGHPUT|tail -1 done | awk '{print $0} {sum += $0} END {printf "%7u\n",sum}' Before patch : 323.87 351.48 339.59 338.62 306.72 204.07 304.93 291.88 202.47 176.88 2840 After patch: 1700.83 2207.98 2070.17 1544.26 2114.76 2124.89 1693.14 1080.91 2216.82 1299.94 18053 Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-06 13:21:27 +08:00
if (tp->packets_out || !tcp_write_queue_empty(sk))
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
goto resched;
TCP: avoid to send keepalive probes if receiving data RFC 1122 says the following: ... Keep-alive packets MUST only be sent when no data or acknowledgement packets have been received for the connection within an interval. ... The acknowledgement packet is reseting the keepalive timer but the data packet isn't. This patch fixes it by checking the timestamp of the last received data packet too when the keepalive timer expires. Signed-off-by: Flavio Leitner <fleitner@redhat.com> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Acked-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-04-27 02:33:27 +08:00
elapsed = keepalive_time_elapsed(tp);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
if (elapsed >= keepalive_time_when(tp)) {
tcp: Add TCP_USER_TIMEOUT socket option. This patch provides a "user timeout" support as described in RFC793. The socket option is also needed for the the local half of RFC5482 "TCP User Timeout Option". TCP_USER_TIMEOUT is a TCP level socket option that takes an unsigned int, when > 0, to specify the maximum amount of time in ms that transmitted data may remain unacknowledged before TCP will forcefully close the corresponding connection and return ETIMEDOUT to the application. If 0 is given, TCP will continue to use the system default. Increasing the user timeouts allows a TCP connection to survive extended periods without end-to-end connectivity. Decreasing the user timeouts allows applications to "fail fast" if so desired. Otherwise it may take upto 20 minutes with the current system defaults in a normal WAN environment. The socket option can be made during any state of a TCP connection, but is only effective during the synchronized states of a connection (ESTABLISHED, FIN-WAIT-1, FIN-WAIT-2, CLOSE-WAIT, CLOSING, or LAST-ACK). Moreover, when used with the TCP keepalive (SO_KEEPALIVE) option, TCP_USER_TIMEOUT will overtake keepalive to determine when to close a connection due to keepalive failure. The option does not change in anyway when TCP retransmits a packet, nor when a keepalive probe will be sent. This option, like many others, will be inherited by an acceptor from its listener. Signed-off-by: H.K. Jerry Chu <hkchu@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-28 03:13:28 +08:00
/* If the TCP_USER_TIMEOUT option is enabled, use that
* to determine when to timeout instead.
*/
if ((icsk->icsk_user_timeout != 0 &&
elapsed >= icsk->icsk_user_timeout &&
icsk->icsk_probes_out > 0) ||
(icsk->icsk_user_timeout == 0 &&
icsk->icsk_probes_out >= keepalive_probes(tp))) {
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
tcp_send_active_reset(sk, GFP_ATOMIC);
tcp_write_err(sk);
goto out;
}
tcp: add TCPWinProbe and TCPKeepAlive SNMP counters Diagnosing problems related to Window Probes has been hard because we lack a counter. TCPWinProbe counts the number of ACK packets a sender has to send at regular intervals to make sure a reverse ACK packet opening back a window had not been lost. TCPKeepAlive counts the number of ACK packets sent to keep TCP flows alive (SO_KEEPALIVE) Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Acked-by: Nandita Dukkipati <nanditad@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-05-07 05:26:25 +08:00
if (tcp_write_wakeup(sk, LINUX_MIB_TCPKEEPALIVE) <= 0) {
[ICSK]: Move TCP congestion avoidance members to icsk This changeset basically moves tcp_sk()->{ca_ops,ca_state,etc} to inet_csk(), minimal renaming/moving done in this changeset to ease review. Most of it is just changes of struct tcp_sock * to struct sock * parameters. With this we move to a state closer to two interesting goals: 1. Generalisation of net/ipv4/tcp_diag.c, becoming inet_diag.c, being used for any INET transport protocol that has struct inet_hashinfo and are derived from struct inet_connection_sock. Keeps the userspace API, that will just not display DCCP sockets, while newer versions of tools can support DCCP. 2. INET generic transport pluggable Congestion Avoidance infrastructure, using the current TCP CA infrastructure with DCCP. Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-10 15:03:31 +08:00
icsk->icsk_probes_out++;
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
elapsed = keepalive_intvl_when(tp);
} else {
/* If keepalive was lost due to local congestion,
* try harder.
*/
elapsed = TCP_RESOURCE_PROBE_INTERVAL;
}
} else {
/* It is tp->rcv_tstamp + keepalive_time_when(tp) */
elapsed = keepalive_time_when(tp) - elapsed;
}
[NET] CORE: Introducing new memory accounting interface. This patch introduces new memory accounting functions for each network protocol. Most of them are renamed from memory accounting functions for stream protocols. At the same time, some stream memory accounting functions are removed since other functions do same thing. Renaming: sk_stream_free_skb() -> sk_wmem_free_skb() __sk_stream_mem_reclaim() -> __sk_mem_reclaim() sk_stream_mem_reclaim() -> sk_mem_reclaim() sk_stream_mem_schedule -> __sk_mem_schedule() sk_stream_pages() -> sk_mem_pages() sk_stream_rmem_schedule() -> sk_rmem_schedule() sk_stream_wmem_schedule() -> sk_wmem_schedule() sk_charge_skb() -> sk_mem_charge() Removeing sk_stream_rfree(): consolidates into sock_rfree() sk_stream_set_owner_r(): consolidates into skb_set_owner_r() sk_stream_mem_schedule() The following functions are added. sk_has_account(): check if the protocol supports accounting sk_mem_uncharge(): do the opposite of sk_mem_charge() In addition, to achieve consolidation, updating sk_wmem_queued is removed from sk_mem_charge(). Next, to consolidate memory accounting functions, this patch adds memory accounting calls to network core functions. Moreover, present memory accounting call is renamed to new accounting call. Finally we replace present memory accounting calls with new interface in TCP and SCTP. Signed-off-by: Takahiro Yasui <tyasui@redhat.com> Signed-off-by: Hideo Aoki <haoki@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-12-31 16:11:19 +08:00
sk_mem_reclaim(sk);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
resched:
[NET]: Introduce inet_connection_sock This creates struct inet_connection_sock, moving members out of struct tcp_sock that are shareable with other INET connection oriented protocols, such as DCCP, that in my private tree already uses most of these members. The functions that operate on these members were renamed, using a inet_csk_ prefix while not being moved yet to a new file, so as to ease the review of these changes. Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-10 11:10:42 +08:00
inet_csk_reset_keepalive_timer (sk, elapsed);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
goto out;
[NET] IPV4: Fix whitespace errors. Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-02-09 22:24:47 +08:00
death:
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
tcp_done(sk);
out:
bh_unlock_sock(sk);
sock_put(sk);
}
tcp: improve latencies of timer triggered events Modern TCP stack highly depends on tcp_write_timer() having a small latency, but current implementation doesn't exactly meet the expectations. When a timer fires but finds the socket is owned by the user, it rearms itself for an additional delay hoping next run will be more successful. tcp_write_timer() for example uses a 50ms delay for next try, and it defeats many attempts to get predictable TCP behavior in term of latencies. Use the recently introduced tcp_release_cb(), so that the user owning the socket will call various handlers right before socket release. This will permit us to post a followup patch to address the tcp_tso_should_defer() syndrome (some deferred packets have to wait RTO timer to be transmitted, while cwnd should allow us to send them sooner) Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Tom Herbert <therbert@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Nandita Dukkipati <nanditad@google.com> Cc: H.K. Jerry Chu <hkchu@google.com> Cc: John Heffner <johnwheffner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-07-20 13:45:50 +08:00
void tcp_init_xmit_timers(struct sock *sk)
{
inet_csk_init_xmit_timers(sk, &tcp_write_timer, &tcp_delack_timer,
&tcp_keepalive_timer);
tcp: internal implementation for pacing BBR congestion control depends on pacing, and pacing is currently handled by sch_fq packet scheduler for performance reasons, and also because implemening pacing with FQ was convenient to truly avoid bursts. However there are many cases where this packet scheduler constraint is not practical. - Many linux hosts are not focusing on handling thousands of TCP flows in the most efficient way. - Some routers use fq_codel or other AQM, but still would like to use BBR for the few TCP flows they initiate/terminate. This patch implements an automatic fallback to internal pacing. Pacing is requested either by BBR or use of SO_MAX_PACING_RATE option. If sch_fq happens to be in the egress path, pacing is delegated to the qdisc, otherwise pacing is done by TCP itself. One advantage of pacing from TCP stack is to get more precise rtt estimations, and less work done from TX completion, since TCP Small queue limits are not generally hit. Setups with single TX queue but many cpus might even benefit from this. Note that unlike sch_fq, we do not take into account header sizes. Taking care of these headers would add additional complexity for no practical differences in behavior. Some performance numbers using 800 TCP_STREAM flows rate limited to ~48 Mbit per second on 40Gbit NIC. If MQ+pfifo_fast is used on the NIC : $ sar -n DEV 1 5 | grep eth 14:48:44 eth0 725743.00 2932134.00 46776.76 4335184.68 0.00 0.00 1.00 14:48:45 eth0 725349.00 2932112.00 46751.86 4335158.90 0.00 0.00 0.00 14:48:46 eth0 725101.00 2931153.00 46735.07 4333748.63 0.00 0.00 0.00 14:48:47 eth0 725099.00 2931161.00 46735.11 4333760.44 0.00 0.00 1.00 14:48:48 eth0 725160.00 2931731.00 46738.88 4334606.07 0.00 0.00 0.00 Average: eth0 725290.40 2931658.20 46747.54 4334491.74 0.00 0.00 0.40 $ vmstat 1 5 procs -----------memory---------- ---swap-- -----io---- -system-- ------cpu----- r b swpd free buff cache si so bi bo in cs us sy id wa st 4 0 0 259825920 45644 2708324 0 0 21 2 247 98 0 0 100 0 0 4 0 0 259823744 45644 2708356 0 0 0 0 2400825 159843 0 19 81 0 0 0 0 0 259824208 45644 2708072 0 0 0 0 2407351 159929 0 19 81 0 0 1 0 0 259824592 45644 2708128 0 0 0 0 2405183 160386 0 19 80 0 0 1 0 0 259824272 45644 2707868 0 0 0 32 2396361 158037 0 19 81 0 0 Now use MQ+FQ : lpaa23:~# echo fq >/proc/sys/net/core/default_qdisc lpaa23:~# tc qdisc replace dev eth0 root mq $ sar -n DEV 1 5 | grep eth 14:49:57 eth0 678614.00 2727930.00 43739.13 4033279.14 0.00 0.00 0.00 14:49:58 eth0 677620.00 2723971.00 43674.69 4027429.62 0.00 0.00 1.00 14:49:59 eth0 676396.00 2719050.00 43596.83 4020125.02 0.00 0.00 0.00 14:50:00 eth0 675197.00 2714173.00 43518.62 4012938.90 0.00 0.00 1.00 14:50:01 eth0 676388.00 2719063.00 43595.47 4020171.64 0.00 0.00 0.00 Average: eth0 676843.00 2720837.40 43624.95 4022788.86 0.00 0.00 0.40 $ vmstat 1 5 procs -----------memory---------- ---swap-- -----io---- -system-- ------cpu----- r b swpd free buff cache si so bi bo in cs us sy id wa st 2 0 0 259832240 46008 2710912 0 0 21 2 223 192 0 1 99 0 0 1 0 0 259832896 46008 2710744 0 0 0 0 1702206 198078 0 17 82 0 0 0 0 0 259830272 46008 2710596 0 0 0 0 1696340 197756 1 17 83 0 0 4 0 0 259829168 46024 2710584 0 0 16 0 1688472 197158 1 17 82 0 0 3 0 0 259830224 46024 2710408 0 0 0 0 1692450 197212 0 18 82 0 0 As expected, number of interrupts per second is very different. Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Van Jacobson <vanj@google.com> Cc: Jerry Chu <hkchu@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-16 19:24:36 +08:00
hrtimer_init(&tcp_sk(sk)->pacing_timer, CLOCK_MONOTONIC,
HRTIMER_MODE_ABS_PINNED);
tcp_sk(sk)->pacing_timer.function = tcp_pace_kick;
tcp: improve latencies of timer triggered events Modern TCP stack highly depends on tcp_write_timer() having a small latency, but current implementation doesn't exactly meet the expectations. When a timer fires but finds the socket is owned by the user, it rearms itself for an additional delay hoping next run will be more successful. tcp_write_timer() for example uses a 50ms delay for next try, and it defeats many attempts to get predictable TCP behavior in term of latencies. Use the recently introduced tcp_release_cb(), so that the user owning the socket will call various handlers right before socket release. This will permit us to post a followup patch to address the tcp_tso_should_defer() syndrome (some deferred packets have to wait RTO timer to be transmitted, while cwnd should allow us to send them sooner) Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Tom Herbert <therbert@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Nandita Dukkipati <nanditad@google.com> Cc: H.K. Jerry Chu <hkchu@google.com> Cc: John Heffner <johnwheffner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-07-20 13:45:50 +08:00
}