Commit Graph

773 Commits

Author SHA1 Message Date
Eric Dumazet 85bdf7db5b tcp: make tcp_space() aware of socket backlog
Jean-Louis Dupond reported poor iscsi TCP receive performance
that we tracked to backlog drops.

Apparently we fail to send window updates reflecting the
fact that we are under stress.

Note that we might lack a proper window increase when
backlog is fully processed, since __release_sock() clears
sk->sk_backlog.len _after_ all skbs have been processed.

This should not matter in practice. If we had a significant
load through socket backlog, we are in a dangerous
situation.

Reported-by: Jean-Louis Dupond <jean-louis@dupond.be>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Tested-by: Jean-Louis Dupond<jean-louis@dupond.be>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-11-30 13:26:54 -08:00
Eric Dumazet ebeef4bccc tcp: hint compiler about sack flows
Tell the compiler that most TCP flows are using SACK these days.

There is no need to add the unlikely() clause in tcp_is_reno(),
the compiler is able to infer it.

Signed-off-by: Eric Dumazet <edumazet@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>
2018-11-30 13:26:53 -08:00
Yafang Shao 213d7767af tcp: clean up STATE_TRACE
Currently we can use bpf or tcp tracepoint to conveniently trace the tcp
state transition at the run time.
So we don't need to do this stuff at the compile time anymore.

Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-11-16 20:28:00 -08:00
Cong Wang 6ab6dfa6bb net: get rid of __tcp_checksum_complete()
__tcp_checksum_complete() is 100% same with __skb_checksum_complete()
and there is no other caller except tcp_checksum_complete().
So, just use __skb_checksum_complete() there.

Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-11-15 11:41:22 -08:00
Stefano Brivio 32bbd8793f net: Convert protocol error handlers from void to int
We'll need this to handle ICMP errors for tunnels without a sending socket
(i.e. FoU and GUE). There, we might have to look up different types of IP
tunnels, registered as network protocols, before we get a match, so we
want this for the error handlers of IPPROTO_IPIP and IPPROTO_IPV6 in both
inet_protos and inet6_protos. These error codes will be used in the next
patch.

For consistency, return sensible error codes in protocol error handlers
whenever handlers can't handle errors because, even if valid, they don't
match a protocol or any of its states.

This has no effect on existing error handling paths.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-11-08 17:13:08 -08:00
Eric Dumazet 3f80e08f40 tcp: add tcp_reset_xmit_timer() helper
With EDT model, SRTT no longer is inflated by pacing delays.

This means that RTO and some other xmit timers might be setup
incorrectly. This is particularly visible with either :

- Very small enforced pacing rates (SO_MAX_PACING_RATE)
- Reduced rto (from the default 200 ms)

This can lead to TCP flows aborts in the worst case,
or spurious retransmits in other cases.

For example, this session gets far more throughput
than the requested 80kbit :

$ netperf -H 127.0.0.2 -l 100 -- -q 10000
MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 127.0.0.2 () port 0 AF_INET
Recv   Send    Send
Socket Socket  Message  Elapsed
Size   Size    Size     Time     Throughput
bytes  bytes   bytes    secs.    10^6bits/sec

540000 262144 262144    104.00      2.66

With the fix :

$ netperf -H 127.0.0.2 -l 100 -- -q 10000
MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 127.0.0.2 () port 0 AF_INET
Recv   Send    Send
Socket Socket  Message  Elapsed
Size   Size    Size     Time     Throughput
bytes  bytes   bytes    secs.    10^6bits/sec

540000 262144 262144    104.00      0.12

EDT allows for better control of rtx timers, since TCP has
a better idea of the earliest departure time of each skb
in the rtx queue. We only have to eventually add to the
timer the difference of the EDT time with current time.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-23 19:42:44 -07:00
Daniel Borkmann c16ee04c9b ulp: remove uid and user_visible members
They are not used anymore and therefore should be removed.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-10-20 23:13:32 -07:00
John Fastabend 02c558b2d5 bpf: sockmap, support for msg_peek in sk_msg with redirect ingress
This adds support for the MSG_PEEK flag when doing redirect to ingress
and receiving on the sk_msg psock queue. Previously the flag was
being ignored which could confuse applications if they expected the
flag to work as normal.

Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-10-17 02:30:32 +02:00
Daniel Borkmann 604326b41a bpf, sockmap: convert to generic sk_msg interface
Add a generic sk_msg layer, and convert current sockmap and later
kTLS over to make use of it. While sk_buff handles network packet
representation from netdevice up to socket, sk_msg handles data
representation from application to socket layer.

This means that sk_msg framework spans across ULP users in the
kernel, and enables features such as introspection or filtering
of data with the help of BPF programs that operate on this data
structure.

Latter becomes in particular useful for kTLS where data encryption
is deferred into the kernel, and as such enabling the kernel to
perform L7 introspection and policy based on BPF for TLS connections
where the record is being encrypted after BPF has run and came to
a verdict. In order to get there, first step is to transform open
coding of scatter-gather list handling into a common core framework
that subsystems can use.

The code itself has been split and refactored into three bigger
pieces: i) the generic sk_msg API which deals with managing the
scatter gather ring, providing helpers for walking and mangling,
transferring application data from user space into it, and preparing
it for BPF pre/post-processing, ii) the plain sock map itself
where sockets can be attached to or detached from; these bits
are independent of i) which can now be used also without sock
map, and iii) the integration with plain TCP as one protocol
to be used for processing L7 application data (later this could
e.g. also be extended to other protocols like UDP). The semantics
are the same with the old sock map code and therefore no change
of user facing behavior or APIs. While pursuing this work it
also helped finding a number of bugs in the old sockmap code
that we've fixed already in earlier commits. The test_sockmap
kselftest suite passes through fine as well.

Joint work with John.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-10-15 12:23:19 -07:00
Daniel Borkmann 1243a51f6c tcp, ulp: remove ulp bits from sockmap
In order to prepare sockmap logic to be used in combination with kTLS
we need to detangle it from ULP, and further split it in later commits
into a generic API.

Joint work with John.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-10-15 12:23:19 -07:00
Eric Dumazet fb420d5d91 tcp/fq: move back to CLOCK_MONOTONIC
In the recent TCP/EDT patch series, I switched TCP and sch_fq
clocks from MONOTONIC to TAI, in order to meet the choice done
earlier for sch_etf packet scheduler.

But sure enough, this broke some setups were the TAI clock
jumps forward (by almost 50 year...), as reported
by Leonard Crestez.

If we want to converge later, we'll probably need to add
an skb field to differentiate the clock bases, or a socket option.

In the meantime, an UDP application will need to use CLOCK_MONOTONIC
base for its SCM_TXTIME timestamps if using fq packet scheduler.

Fixes: 72b0094f91 ("tcp: switch tcp_clock_ns() to CLOCK_TAI base")
Fixes: 142537e419 ("net_sched: sch_fq: switch to CLOCK_TAI")
Fixes: fd2bca2aa7 ("tcp: switch internal pacing timer to CLOCK_TAI")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Leonard Crestez <leonard.crestez@nxp.com>
Tested-by: Leonard Crestez <leonard.crestez@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-01 23:18:51 -07:00
Eric Dumazet d3edd06ea8 tcp: provide earliest departure time in skb->tstamp
Switch internal TCP skb->skb_mstamp to skb->skb_mstamp_ns,
from usec units to nsec units.

Do not clear skb->tstamp before entering IP stacks in TX,
so that qdisc or devices can implement pacing based on the
earliest departure time instead of socket sk->sk_pacing_rate

Packets are fed with tcp_wstamp_ns, and following patch
will update tcp_wstamp_ns when both TCP and sch_fq switch to
the earliest departure time mechanism.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-09-21 19:37:59 -07:00
Eric Dumazet 9799ccb0e9 tcp: add tcp_wstamp_ns socket field
TCP will soon provide earliest departure time on TX skbs.
It needs to track this in a new variable.

tcp_mstamp_refresh() needs to update this variable, and
became too big to stay an inline.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-09-21 19:37:59 -07:00
Eric Dumazet 2fd66ffba5 tcp: introduce tcp_skb_timestamp_us() helper
There are few places where TCP reads skb->skb_mstamp expecting
a value in usec unit.

skb->tstamp (aka skb->skb_mstamp) will soon store CLOCK_TAI nsec value.

Add tcp_skb_timestamp_us() to provide proper conversion when needed.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-09-21 19:37:59 -07:00
Eric Dumazet 72b0094f91 tcp: switch tcp_clock_ns() to CLOCK_TAI base
TCP pacing is either implemented in sch_fq or internally.
We have the goal of being able to offload pacing on the NICS.

TCP will soon provide per skb skb->tstamp as early departure time.

Like ETF in commit 25db26a913 ("net/sched: Introduce the ETF Qdisc")
we chose CLOCK_T as the clock base, so that TCP and pacers can share
a common clock, to get better RTT samples (without pacing artificially
inflating these samples).

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-09-21 19:37:59 -07:00
Daniel Borkmann 037b0b86ec tcp, ulp: add alias for all ulp modules
Lets not turn the TCP ULP lookup into an arbitrary module loader as
we only intend to load ULP modules through this mechanism, not other
unrelated kernel modules:

  [root@bar]# cat foo.c
  #include <sys/types.h>
  #include <sys/socket.h>
  #include <linux/tcp.h>
  #include <linux/in.h>

  int main(void)
  {
      int sock = socket(PF_INET, SOCK_STREAM, 0);
      setsockopt(sock, IPPROTO_TCP, TCP_ULP, "sctp", sizeof("sctp"));
      return 0;
  }

  [root@bar]# gcc foo.c -O2 -Wall
  [root@bar]# lsmod | grep sctp
  [root@bar]# ./a.out
  [root@bar]# lsmod | grep sctp
  sctp                 1077248  4
  libcrc32c              16384  3 nf_conntrack,nf_nat,sctp
  [root@bar]#

Fix it by adding module alias to TCP ULP modules, so probing module
via request_module() will be limited to tcp-ulp-[name]. The existing
modules like kTLS will load fine given tcp-ulp-tls alias, but others
will fail to load:

  [root@bar]# lsmod | grep sctp
  [root@bar]# ./a.out
  [root@bar]# lsmod | grep sctp
  [root@bar]#

Sockmap is not affected from this since it's either built-in or not.

Fixes: 734942cc4e ("tcp: ULP infrastructure")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-08-16 14:58:07 -07:00
Martin KaFai Lau 40a1227ea8 tcp: Avoid TCP syncookie rejected by SO_REUSEPORT socket
Although the actual cookie check "__cookie_v[46]_check()" does
not involve sk specific info, it checks whether the sk has recent
synq overflow event in "tcp_synq_no_recent_overflow()".  The
tcp_sk(sk)->rx_opt.ts_recent_stamp is updated every second
when it has sent out a syncookie (through "tcp_synq_overflow()").

The above per sk "recent synq overflow event timestamp" works well
for non SO_REUSEPORT use case.  However, it may cause random
connection request reject/discard when SO_REUSEPORT is used with
syncookie because it fails the "tcp_synq_no_recent_overflow()"
test.

When SO_REUSEPORT is used, it usually has multiple listening
socks serving TCP connection requests destinated to the same local IP:PORT.
There are cases that the TCP-ACK-COOKIE may not be received
by the same sk that sent out the syncookie.  For example,
if reuse->socks[] began with {sk0, sk1},
1) sk1 sent out syncookies and tcp_sk(sk1)->rx_opt.ts_recent_stamp
   was updated.
2) the reuse->socks[] became {sk1, sk2} later.  e.g. sk0 was first closed
   and then sk2 was added.  Here, sk2 does not have ts_recent_stamp set.
   There are other ordering that will trigger the similar situation
   below but the idea is the same.
3) When the TCP-ACK-COOKIE comes back, sk2 was selected.
   "tcp_synq_no_recent_overflow(sk2)" returns true. In this case,
   all syncookies sent by sk1 will be handled (and rejected)
   by sk2 while sk1 is still alive.

The userspace may create and remove listening SO_REUSEPORT sockets
as it sees fit.  E.g. Adding new thread (and SO_REUSEPORT sock) to handle
incoming requests, old process stopping and new process starting...etc.
With or without SO_ATTACH_REUSEPORT_[CB]BPF,
the sockets leaving and joining a reuseport group makes picking
the same sk to check the syncookie very difficult (if not impossible).

The later patches will allow bpf prog more flexibility in deciding
where a sk should be located in a bpf map and selecting a particular
SO_REUSEPORT sock as it sees fit.  e.g. Without closing any sock,
replace the whole bpf reuseport_array in one map_update() by using
map-in-map.  Getting the syncookie check working smoothly across
socks in the same "reuse->socks[]" is important.

A partial solution is to set the newly added sk's ts_recent_stamp
to the max ts_recent_stamp of a reuseport group but that will require
to iterate through reuse->socks[]  OR
pessimistically set it to "now - TCP_SYNCOOKIE_VALID" when a sk is
joining a reuseport group.  However, neither of them will solve the
existing sk getting moved around the reuse->socks[] and that
sk may not have ts_recent_stamp updated, unlikely under continuous
synflood but not impossible.

This patch opts to treat the reuseport group as a whole when
considering the last synq overflow timestamp since
they are serving the same IP:PORT from the userspace
(and BPF program) perspective.

"synq_overflow_ts" is added to "struct sock_reuseport".
The tcp_synq_overflow() and tcp_synq_no_recent_overflow()
will update/check reuse->synq_overflow_ts if the sk is
in a reuseport group.  Similar to the reuseport decision in
__inet_lookup_listener(), both sk->sk_reuseport and
sk->sk_reuseport_cb are tested for SO_REUSEPORT usage.
Update on "synq_overflow_ts" happens at roughly once
every second.

A synflood test was done with a 16 rx-queues and 16 reuseport sockets.
No meaningful performance change is observed.  Before and
after the change is ~9Mpps in IPv4.

Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-08-11 01:58:45 +02:00
David S. Miller 19725496da Merge ra.kernel.org:/pub/scm/linux/kernel/git/davem/net 2018-07-24 19:21:58 -07:00
David Ahern 24b711edfc net/ipv6: Fix linklocal to global address with VRF
Example setup:
    host: ip -6 addr add dev eth1 2001:db8:104::4
           where eth1 is enslaved to a VRF

    switch: ip -6 ro add 2001:db8:104::4/128 dev br1
            where br1 only has an LLA

           ping6 2001:db8:104::4
           ssh   2001:db8:104::4

(NOTE: UDP works fine if the PKTINFO has the address set to the global
address and ifindex is set to the index of eth1 with a destination an
LLA).

For ICMP, icmp6_iif needs to be updated to check if skb->dev is an
L3 master. If it is then return the ifindex from rt6i_idev similar
to what is done for loopback.

For TCP, restore the original tcp_v6_iif definition which is needed in
most places and add a new tcp_v6_iif_l3_slave that considers the
l3_slave variability. This latter check is only needed for socket
lookups.

Fixes: 9ff7438460 ("net: vrf: Handle ipv6 multicast and link-local addresses")
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-07-21 19:31:46 -07:00
David S. Miller c4c5551df1 Merge ra.kernel.org:/pub/scm/linux/kernel/git/torvalds/linux
All conflicts were trivial overlapping changes, so reasonably
easy to resolve.

Signed-off-by: David S. Miller <davem@davemloft.net>
2018-07-20 21:17:12 -07:00
Yuchung Cheng a0496ef2c2 tcp: do not delay ACK in DCTCP upon CE status change
Per DCTCP RFC8257 (Section 3.2) the ACK reflecting the CE status change
has to be sent immediately so the sender can respond quickly:

""" When receiving packets, the CE codepoint MUST be processed as follows:

   1.  If the CE codepoint is set and DCTCP.CE is false, set DCTCP.CE to
       true and send an immediate ACK.

   2.  If the CE codepoint is not set and DCTCP.CE is true, set DCTCP.CE
       to false and send an immediate ACK.
"""

Previously DCTCP implementation may continue to delay the ACK. This
patch fixes that to implement the RFC by forcing an immediate ACK.

Tested with this packetdrill script provided by Larry Brakmo

0.000 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3
0.000 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
0.000 setsockopt(3, SOL_TCP, TCP_CONGESTION, "dctcp", 5) = 0
0.000 bind(3, ..., ...) = 0
0.000 listen(3, 1) = 0

0.100 < [ect0] SEW 0:0(0) win 32792 <mss 1000,sackOK,nop,nop,nop,wscale 7>
0.100 > SE. 0:0(0) ack 1 <mss 1460,nop,nop,sackOK,nop,wscale 8>
0.110 < [ect0] . 1:1(0) ack 1 win 257
0.200 accept(3, ..., ...) = 4
   +0 setsockopt(4, SOL_SOCKET, SO_DEBUG, [1], 4) = 0

0.200 < [ect0] . 1:1001(1000) ack 1 win 257
0.200 > [ect01] . 1:1(0) ack 1001

0.200 write(4, ..., 1) = 1
0.200 > [ect01] P. 1:2(1) ack 1001

0.200 < [ect0] . 1001:2001(1000) ack 2 win 257
+0.005 < [ce] . 2001:3001(1000) ack 2 win 257

+0.000 > [ect01] . 2:2(0) ack 2001
// Previously the ACK below would be delayed by 40ms
+0.000 > [ect01] E. 2:2(0) ack 3001

+0.500 < F. 9501:9501(0) ack 4 win 257

Signed-off-by: Yuchung Cheng <ycheng@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-07-20 14:32:23 -07:00
Yuchung Cheng 27cde44a25 tcp: do not cancel delay-AcK on DCTCP special ACK
Currently when a DCTCP receiver delays an ACK and receive a
data packet with a different CE mark from the previous one's, it
sends two immediate ACKs acking previous and latest sequences
respectly (for ECN accounting).

Previously sending the first ACK may mark off the delayed ACK timer
(tcp_event_ack_sent). This may subsequently prevent sending the
second ACK to acknowledge the latest sequence (tcp_ack_snd_check).
The culprit is that tcp_send_ack() assumes it always acknowleges
the latest sequence, which is not true for the first special ACK.

The fix is to not make the assumption in tcp_send_ack and check the
actual ack sequence before cancelling the delayed ACK. Further it's
safer to pass the ack sequence number as a local variable into
tcp_send_ack routine, instead of intercepting tp->rcv_nxt to avoid
future bugs like this.

Reported-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-07-20 14:32:23 -07:00
Yuchung Cheng a69258f7aa tcp: remove DELAYED ACK events in DCTCP
After fixing the way DCTCP tracking delayed ACKs, the delayed-ACK
related callbacks are no longer needed

Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Lawrence Brakmo <brakmo@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-07-13 18:30:19 -07:00
Arnd Bergmann cca9bab1b7 tcp: use monotonic timestamps for PAWS
Using get_seconds() for timestamps is deprecated since it can lead
to overflows on 32-bit systems. While the interface generally doesn't
overflow until year 2106, the specific implementation of the TCP PAWS
algorithm breaks in 2038 when the intermediate signed 32-bit timestamps
overflow.

A related problem is that the local timestamps in CLOCK_REALTIME form
lead to unexpected behavior when settimeofday is called to set the system
clock backwards or forwards by more than 24 days.

While the first problem could be solved by using an overflow-safe method
of comparing the timestamps, a nicer solution is to use a monotonic
clocksource with ktime_get_seconds() that simply doesn't overflow (at
least not until 136 years after boot) and that doesn't change during
settimeofday().

To make 32-bit and 64-bit architectures behave the same way here, and
also save a few bytes in the tcp_options_received structure, I'm changing
the type to a 32-bit integer, which is now safe on all architectures.

Finally, the ts_recent_stamp field also (confusingly) gets used to store
a jiffies value in tcp_synq_overflow()/tcp_synq_no_recent_overflow().
This is currently safe, but changing the type to 32-bit requires
some small changes there to keep it working.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-07-12 14:50:40 -07:00
Deepti Raghavan 4929c9428a tcp: expose both send and receive intervals for rate sample
Congestion control algorithms, which access the rate sample
through the tcp_cong_control function, only have access to the maximum
of the send and receive interval, for cases where the acknowledgment
rate may be inaccurate due to ACK compression or decimation. Algorithms
may want to use send rates and receive rates as separate signals.

Signed-off-by: Deepti Raghavan <deeptir@mit.edu>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-07-11 23:01:56 -07:00
John Fastabend 0ea488ff8d bpf: sockmap, convert bpf_compute_data_pointers to bpf_*_sk_skb
In commit

  'bpf: bpf_compute_data uses incorrect cb structure' (8108a77515)

we added the routine bpf_compute_data_end_sk_skb() to compute the
correct data_end values, but this has since been lost. In kernel
v4.14 this was correct and the above patch was applied in it
entirety. Then when v4.14 was merged into v4.15-rc1 net-next tree
we lost the piece that renamed bpf_compute_data_pointers to the
new function bpf_compute_data_end_sk_skb. This was done here,

e1ea2f9856 ("Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net")

When it conflicted with the following rename patch,

6aaae2b6c4 ("bpf: rename bpf_compute_data_end into bpf_compute_data_pointers")

Finally, after a refactor I thought even the function
bpf_compute_data_end_sk_skb() was no longer needed and it was
erroneously removed.

However, we never reverted the sk_skb_convert_ctx_access() usage of
tcp_skb_cb which had been committed and survived the merge conflict.
Here we fix this by adding back the helper and *_data_end_sk_skb()
usage. Using the bpf_skc_data_end mapping is not correct because it
expects a qdisc_skb_cb object but at the sock layer this is not the
case. Even though it happens to work here because we don't overwrite
any data in-use at the socket layer and the cb structure is cleared
later this has potential to create some subtle issues. But, even
more concretely the filter.c access check uses tcp_skb_cb.

And by some act of chance though,

struct bpf_skb_data_end {
        struct qdisc_skb_cb        qdisc_cb;             /*     0    28 */

        /* XXX 4 bytes hole, try to pack */

        void *                     data_meta;            /*    32     8 */
        void *                     data_end;             /*    40     8 */

        /* size: 48, cachelines: 1, members: 3 */
        /* sum members: 44, holes: 1, sum holes: 4 */
        /* last cacheline: 48 bytes */
};

and then tcp_skb_cb,

struct tcp_skb_cb {
	[...]
                struct {
                        __u32      flags;                /*    24     4 */
                        struct sock * sk_redir;          /*    32     8 */
                        void *     data_end;             /*    40     8 */
                } bpf;                                   /*          24 */
        };

So when we use offset_of() to track down the byte offset we get 40 in
either case and everything continues to work. Fix this mess and use
correct structures its unclear how long this might actually work for
until someone moves the structs around.

Reported-by: Martin KaFai Lau <kafai@fb.com>
Fixes: e1ea2f9856 ("Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net")
Fixes: 6aaae2b6c4 ("bpf: rename bpf_compute_data_end into bpf_compute_data_pointers")
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-07-07 15:19:30 -07:00
David S. Miller 5cd3da4ba2 Merge ra.kernel.org:/pub/scm/linux/kernel/git/davem/net
Simple overlapping changes in stmmac driver.

Adjust skb_gro_flush_final_remcsum function signature to make GRO list
changes in net-next, as per Stephen Rothwell's example merge
resolution.

Signed-off-by: David S. Miller <davem@davemloft.net>
2018-07-03 10:29:26 +09:00
Linus Torvalds a11e1d432b Revert changes to convert to ->poll_mask() and aio IOCB_CMD_POLL
The poll() changes were not well thought out, and completely
unexplained.  They also caused a huge performance regression, because
"->poll()" was no longer a trivial file operation that just called down
to the underlying file operations, but instead did at least two indirect
calls.

Indirect calls are sadly slow now with the Spectre mitigation, but the
performance problem could at least be largely mitigated by changing the
"->get_poll_head()" operation to just have a per-file-descriptor pointer
to the poll head instead.  That gets rid of one of the new indirections.

But that doesn't fix the new complexity that is completely unwarranted
for the regular case.  The (undocumented) reason for the poll() changes
was some alleged AIO poll race fixing, but we don't make the common case
slower and more complex for some uncommon special case, so this all
really needs way more explanations and most likely a fundamental
redesign.

[ This revert is a revert of about 30 different commits, not reverted
  individually because that would just be unnecessarily messy  - Linus ]

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-06-28 10:40:47 -07:00
David Miller d4546c2509 net: Convert GRO SKB handling to list_head.
Manage pending per-NAPI GRO packets via list_head.

Return an SKB pointer from the GRO receive handlers.  When GRO receive
handlers return non-NULL, it means that this SKB needs to be completed
at this time and removed from the NAPI queue.

Several operations are greatly simplified by this transformation,
especially timing out the oldest SKB in the list when gro_count
exceeds MAX_GRO_SKBS, and napi_gro_flush() which walks the queue
in reverse order.

Signed-off-by: David S. Miller <davem@davemloft.net>
2018-06-26 11:33:04 +09:00
Eric Dumazet cadefe5f58 tcp_bbr: fix bbr pacing rate for internal pacing
This commit makes BBR use only the MSS (without any headers) to
calculate pacing rates when internal TCP-layer pacing is used.

This is necessary to achieve the correct pacing behavior in this case,
since tcp_internal_pacing() uses only the payload length to calculate
pacing delays.

Signed-off-by: Kevin Yang <yyd@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-06-22 13:59:22 +09:00
Linus Torvalds 1c8c5a9d38 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next
Pull networking updates from David Miller:

 1) Add Maglev hashing scheduler to IPVS, from Inju Song.

 2) Lots of new TC subsystem tests from Roman Mashak.

 3) Add TCP zero copy receive and fix delayed acks and autotuning with
    SO_RCVLOWAT, from Eric Dumazet.

 4) Add XDP_REDIRECT support to mlx5 driver, from Jesper Dangaard
    Brouer.

 5) Add ttl inherit support to vxlan, from Hangbin Liu.

 6) Properly separate ipv6 routes into their logically independant
    components. fib6_info for the routing table, and fib6_nh for sets of
    nexthops, which thus can be shared. From David Ahern.

 7) Add bpf_xdp_adjust_tail helper, which can be used to generate ICMP
    messages from XDP programs. From Nikita V. Shirokov.

 8) Lots of long overdue cleanups to the r8169 driver, from Heiner
    Kallweit.

 9) Add BTF ("BPF Type Format"), from Martin KaFai Lau.

10) Add traffic condition monitoring to iwlwifi, from Luca Coelho.

11) Plumb extack down into fib_rules, from Roopa Prabhu.

12) Add Flower classifier offload support to igb, from Vinicius Costa
    Gomes.

13) Add UDP GSO support, from Willem de Bruijn.

14) Add documentation for eBPF helpers, from Quentin Monnet.

15) Add TLS tx offload to mlx5, from Ilya Lesokhin.

16) Allow applications to be given the number of bytes available to read
    on a socket via a control message returned from recvmsg(), from
    Soheil Hassas Yeganeh.

17) Add x86_32 eBPF JIT compiler, from Wang YanQing.

18) Add AF_XDP sockets, with zerocopy support infrastructure as well.
    From Björn Töpel.

19) Remove indirect load support from all of the BPF JITs and handle
    these operations in the verifier by translating them into native BPF
    instead. From Daniel Borkmann.

20) Add GRO support to ipv6 gre tunnels, from Eran Ben Elisha.

21) Allow XDP programs to do lookups in the main kernel routing tables
    for forwarding. From David Ahern.

22) Allow drivers to store hardware state into an ELF section of kernel
    dump vmcore files, and use it in cxgb4. From Rahul Lakkireddy.

23) Various RACK and loss detection improvements in TCP, from Yuchung
    Cheng.

24) Add TCP SACK compression, from Eric Dumazet.

25) Add User Mode Helper support and basic bpfilter infrastructure, from
    Alexei Starovoitov.

26) Support ports and protocol values in RTM_GETROUTE, from Roopa
    Prabhu.

27) Support bulking in ->ndo_xdp_xmit() API, from Jesper Dangaard
    Brouer.

28) Add lots of forwarding selftests, from Petr Machata.

29) Add generic network device failover driver, from Sridhar Samudrala.

* ra.kernel.org:/pub/scm/linux/kernel/git/davem/net-next: (1959 commits)
  strparser: Add __strp_unpause and use it in ktls.
  rxrpc: Fix terminal retransmission connection ID to include the channel
  net: hns3: Optimize PF CMDQ interrupt switching process
  net: hns3: Fix for VF mailbox receiving unknown message
  net: hns3: Fix for VF mailbox cannot receiving PF response
  bnx2x: use the right constant
  Revert "net: sched: cls: Fix offloading when ingress dev is vxlan"
  net: dsa: b53: Fix for brcm tag issue in Cygnus SoC
  enic: fix UDP rss bits
  netdev-FAQ: clarify DaveM's position for stable backports
  rtnetlink: validate attributes in do_setlink()
  mlxsw: Add extack messages for port_{un, }split failures
  netdevsim: Add extack error message for devlink reload
  devlink: Add extack to reload and port_{un, }split operations
  net: metrics: add proper netlink validation
  ipmr: fix error path when ipmr_new_table fails
  ip6mr: only set ip6mr_table from setsockopt when ip6mr_new_table succeeds
  net: hns3: remove unused hclgevf_cfg_func_mta_filter
  netfilter: provide udp*_lib_lookup for nf_tproxy
  qed*: Utilize FW 8.37.2.0
  ...
2018-06-06 18:39:49 -07:00
Linus Torvalds 408afb8d78 Merge branch 'work.aio-1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull aio updates from Al Viro:
 "Majority of AIO stuff this cycle. aio-fsync and aio-poll, mostly.

  The only thing I'm holding back for a day or so is Adam's aio ioprio -
  his last-minute fixup is trivial (missing stub in !CONFIG_BLOCK case),
  but let it sit in -next for decency sake..."

* 'work.aio-1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (46 commits)
  aio: sanitize the limit checking in io_submit(2)
  aio: fold do_io_submit() into callers
  aio: shift copyin of iocb into io_submit_one()
  aio_read_events_ring(): make a bit more readable
  aio: all callers of aio_{read,write,fsync,poll} treat 0 and -EIOCBQUEUED the same way
  aio: take list removal to (some) callers of aio_complete()
  aio: add missing break for the IOCB_CMD_FDSYNC case
  random: convert to ->poll_mask
  timerfd: convert to ->poll_mask
  eventfd: switch to ->poll_mask
  pipe: convert to ->poll_mask
  crypto: af_alg: convert to ->poll_mask
  net/rxrpc: convert to ->poll_mask
  net/iucv: convert to ->poll_mask
  net/phonet: convert to ->poll_mask
  net/nfc: convert to ->poll_mask
  net/caif: convert to ->poll_mask
  net/bluetooth: convert to ->poll_mask
  net/sctp: convert to ->poll_mask
  net/tipc: convert to ->poll_mask
  ...
2018-06-04 13:57:43 -07:00
Yafang Shao 3d97d88e80 tcp: minor optimization around tcp_hdr() usage in receive path
This is additional to the
commit ea1627c20c ("tcp: minor optimizations around tcp_hdr() usage").
At this point, skb->data is same with tcp_hdr() as tcp header has not
been pulled yet. So use the less expensive one to get the tcp header.

Remove the third parameter of tcp_rcv_established() and put it into
the function body.

Furthermore, the local variables are listed as a reverse christmas tree :)

Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-31 13:20:47 -04:00
Christoph Hellwig 2c7d3daceb net/tcp: convert to ->poll_mask
Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-05-26 09:16:44 +02:00
Eric Dumazet 5d9f4262b7 tcp: add SACK compression
When TCP receives an out-of-order packet, it immediately sends
a SACK packet, generating network load but also forcing the
receiver to send 1-MSS pathological packets, increasing its
RTX queue length/depth, and thus processing time.

Wifi networks suffer from this aggressive behavior, but generally
speaking, all these SACK packets add fuel to the fire when networks
are under congestion.

This patch adds a high resolution timer and tp->compressed_ack counter.

Instead of sending a SACK, we program this timer with a small delay,
based on RTT and capped to 1 ms :

	delay = min ( 5 % of RTT, 1 ms)

If subsequent SACKs need to be sent while the timer has not yet
expired, we simply increment tp->compressed_ack.

When timer expires, a SACK is sent with the latest information.
Whenever an ACK is sent (if data is sent, or if in-order
data is received) timer is canceled.

Note that tcp_sack_new_ofo_skb() is able to force a SACK to be sent
if the sack blocks need to be shuffled, even if the timer has not
expired.

A new SNMP counter is added in the following patch.

Two other patches add sysctls to allow changing the 1,000,000 and 44
values that this commit hard-coded.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Acked-by: Toke Høiland-Jørgensen <toke@toke.dk>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-18 11:40:27 -04:00
Eric Dumazet cf0dd20372 tcp: use __sock_put() instead of sock_put() in tcp_clear_xmit_timers()
Socket can not disappear under us.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-18 11:40:27 -04:00
Yuchung Cheng b8fef65a8a tcp: new helper tcp_rack_skb_timeout
Create and export a new helper tcp_rack_skb_timeout and move tcp_is_rack
to prepare the final RTO change.

Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Soheil Hassas Yeganeh <soheil@google.com>
Reviewed-by: Priyaranjan Jha <priyarjha@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-17 15:41:29 -04:00
Yuchung Cheng d716bfdb10 tcp: account lost retransmit after timeout
The previous approach for the lost and retransmit bits was to
wipe the slate clean: zero all the lost and retransmit bits,
correspondingly zero the lost_out and retrans_out counters, and
then add back the lost bits (and correspondingly increment lost_out).

The new approach is to treat this very much like marking packets
lost in fast recovery. We don’t wipe the slate clean. We just say
that for all packets that were not yet marked sacked or lost, we now
mark them as lost in exactly the same way we do for fast recovery.

This fixes the lost retransmit accounting at RTO time and greatly
simplifies the RTO code by sharing much of the logic with Fast
Recovery.

Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Soheil Hassas Yeganeh <soheil@google.com>
Reviewed-by: Priyaranjan Jha <priyarjha@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-17 15:41:29 -04:00
Yuchung Cheng 6ac06ecd3a tcp: simpler NewReno implementation
This is a rewrite of NewReno loss recovery implementation that is
simpler and standalone for readability and better performance by
using less states.

Note that NewReno refers to RFC6582 as a modification to the fast
recovery algorithm. It is used only if the connection does not
support SACK in Linux. It should not to be confused with the Reno
(AIMD) congestion control.

Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Soheil Hassas Yeganeh <soheil@google.com>
Reviewed-by: Priyaranjan Jha <priyarjha@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-17 15:41:28 -04:00
Yuchung Cheng 20b654dfe1 tcp: support DUPACK threshold in RACK
This patch adds support for the classic DUPACK threshold rule
(#DupThresh) in RACK.

When the number of packets SACKed is greater or equal to the
threshold, RACK sets the reordering window to zero which would
immediately mark all the unsacked packets below the highest SACKed
sequence lost. Since this approach is known to not work well with
reordering, RACK only uses it if no reordering has been observed.

The DUPACK threshold rule is a particularly useful extension to the
fast recoveries triggered by RACK reordering timer. For example
data-center transfers where the RTT is much smaller than a timer
tick, or high RTT path where the default RTT/4 may take too long.

Note that this patch differs slightly from RFC6675. RFC6675
considers a packet lost when at least #DupThresh higher-sequence
packets are SACKed.

With RACK, for connections that have seen reordering, RACK
continues to use a dynamically-adaptive time-based reordering
window to detect losses. But for connections on which we have not
yet seen reordering, this patch considers a packet lost when at
least one higher sequence packet is SACKed and the total number
of SACKed packets is at least DupThresh. For example, suppose a
connection has not seen reordering, and sends 10 packets, and
packets 3, 5, 7 are SACKed. RFC6675 considers packets 1 and 2
lost. RACK considers packets 1, 2, 4, 6 lost.

There is some small risk of spurious retransmits here due to
reordering. However, this is mostly limited to the first flight of
a connection on which the sender receives SACKs from reordering.
And RFC 6675 and FACK loss detection have a similar risk on the
first flight with reordering (it's just that the risk of spurious
retransmits from reordering was slightly narrower for those older
algorithms due to the margin of 3*MSS).

Also the minimum reordering window is reduced from 1 msec to 0
to recover quicker on short RTT transfers. Therefore RACK is more
aggressive in marking packets lost during recovery to reduce the
reordering window timeouts.

Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Soheil Hassas Yeganeh <soheil@google.com>
Reviewed-by: Priyaranjan Jha <priyarjha@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-17 15:41:28 -04:00
David S. Miller b9f672af14 Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Daniel Borkmann says:

====================
pull-request: bpf-next 2018-05-17

The following pull-request contains BPF updates for your *net-next* tree.

The main changes are:

1) Provide a new BPF helper for doing a FIB and neighbor lookup
   in the kernel tables from an XDP or tc BPF program. The helper
   provides a fast-path for forwarding packets. The API supports
   IPv4, IPv6 and MPLS protocols, but currently IPv4 and IPv6 are
   implemented in this initial work, from David (Ahern).

2) Just a tiny diff but huge feature enabled for nfp driver by
   extending the BPF offload beyond a pure host processing offload.
   Offloaded XDP programs are allowed to set the RX queue index and
   thus opening the door for defining a fully programmable RSS/n-tuple
   filter replacement. Once BPF decided on a queue already, the device
   data-path will skip the conventional RSS processing completely,
   from Jakub.

3) The original sockmap implementation was array based similar to
   devmap. However unlike devmap where an ifindex has a 1:1 mapping
   into the map there are use cases with sockets that need to be
   referenced using longer keys. Hence, sockhash map is added reusing
   as much of the sockmap code as possible, from John.

4) Introduce BTF ID. The ID is allocatd through an IDR similar as
   with BPF maps and progs. It also makes BTF accessible to user
   space via BPF_BTF_GET_FD_BY_ID and adds exposure of the BTF data
   through BPF_OBJ_GET_INFO_BY_FD, from Martin.

5) Enable BPF stackmap with build_id also in NMI context. Due to the
   up_read() of current->mm->mmap_sem build_id cannot be parsed.
   This work defers the up_read() via a per-cpu irq_work so that
   at least limited support can be enabled, from Song.

6) Various BPF JIT follow-up cleanups and fixups after the LD_ABS/LD_IND
   JIT conversion as well as implementation of an optimized 32/64 bit
   immediate load in the arm64 JIT that allows to reduce the number of
   emitted instructions; in case of tested real-world programs they
   were shrinking by three percent, from Daniel.

7) Add ifindex parameter to the libbpf loader in order to enable
   BPF offload support. Right now only iproute2 can load offloaded
   BPF and this will also enable libbpf for direct integration into
   other applications, from David (Beckett).

8) Convert the plain text documentation under Documentation/bpf/ into
   RST format since this is the appropriate standard the kernel is
   moving to for all documentation. Also add an overview README.rst,
   from Jesper.

9) Add __printf verification attribute to the bpf_verifier_vlog()
   helper. Though it uses va_list we can still allow gcc to check
   the format string, from Mathieu.

10) Fix a bash reference in the BPF selftest's Makefile. The '|& ...'
    is a bash 4.0+ feature which is not guaranteed to be available
    when calling out to shell, therefore use a more portable variant,
    from Joe.

11) Fix a 64 bit division in xdp_umem_reg() by using div_u64()
    instead of relying on the gcc built-in, from Björn.

12) Fix a sock hashmap kmalloc warning reported by syzbot when an
    overly large key size is used in hashmap then causing overflows
    in htab->elem_size. Reject bogus attr->key_size early in the
    sock_hash_alloc(), from Yonghong.

13) Ensure in BPF selftests when urandom_read is being linked that
    --build-id is always enabled so that test_stacktrace_build_id[_nmi]
    won't be failing, from Alexei.

14) Add bitsperlong.h as well as errno.h uapi headers into the tools
    header infrastructure which point to one of the arch specific
    uapi headers. This was needed in order to fix a build error on
    some systems for the BPF selftests, from Sirio.

15) Allow for short options to be used in the xdp_monitor BPF sample
    code. And also a bpf.h tools uapi header sync in order to fix a
    selftest build failure. Both from Prashant.

16) More formally clarify the meaning of ID in the direct packet access
    section of the BPF documentation, from Wang.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-16 22:47:11 -04:00
Christoph Hellwig 37d849bb42 ipv{4,6}/tcp: simplify procfs registration
Avoid most of the afinfo indirections and just call the proc helpers
directly.

Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-05-16 07:23:35 +02:00
John Fastabend e5cd3abcb3 bpf: sockmap, refactor sockmap routines to work with hashmap
This patch only refactors the existing sockmap code. This will allow
much of the psock initialization code path and bpf helper codes to
work for both sockmap bpf map types that are backed by an array, the
currently supported type, and the new hash backed bpf map type
sockhash.

Most the fallout comes from three changes,

  - Pushing bpf programs into an independent structure so we
    can use it from the htab struct in the next patch.
  - Generalizing helpers to use void *key instead of the hardcoded
    u32.
  - Instead of passing map/key through the metadata we now do
    the lookup inline. This avoids storing the key in the metadata
    which will be useful when keys can be longer than 4 bytes. We
    rename the sk pointers to sk_redir at this point as well to
    avoid any confusion between the current sk pointer and the
    redirect pointer sk_redir.

Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-05-15 17:19:59 +02:00
Eric Dumazet 73a6bab5aa tcp: switch pacing timer to softirq based hrtimer
linux-4.16 got support for softirq based hrtimers.
TCP can switch its pacing hrtimer to this variant, since this
avoids going through a tasklet and some atomic operations.

pacing timer logic looks like other (jiffies based) tcp timers.

v2: use hrtimer_try_to_cancel() in tcp_clear_xmit_timers()
    to correctly release reference on socket if needed.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-11 12:24:37 -04:00
Ilya Lesokhin 6dac152355 tcp: Add clean acked data hook
Called when a TCP segment is acknowledged.
Could be used by application protocols who hold additional
metadata associated with the stream data.

This is required by TLS device offload to release
metadata associated with acknowledged TLS records.

Signed-off-by: Ilya Lesokhin <ilyal@mellanox.com>
Signed-off-by: Boris Pismenny <borisp@mellanox.com>
Signed-off-by: Aviad Yehezkel <aviadye@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-01 09:42:46 -04:00
Eric Dumazet 93ab6cc691 tcp: implement mmap() for zero copy receive
Some networks can make sure TCP payload can exactly fit 4KB pages,
with well chosen MSS/MTU and architectures.

Implement mmap() system call so that applications can avoid
copying data without complex splice() games.

Note that a successful mmap( X bytes) on TCP socket is consuming
bytes, as if recvmsg() has been done. (tp->copied += X)

Only PROT_READ mappings are accepted, as skb page frags
are fundamentally shared and read only.

If tcp_mmap() finds data that is not a full page, or a patch of
urgent data, -EINVAL is returned, no bytes are consumed.

Application must fallback to recvmsg() to read the problematic sequence.

mmap() wont block,  regardless of socket being in blocking or
non-blocking mode. If not enough bytes are in receive queue,
mmap() would return -EAGAIN, or -EIO if socket is in a state
where no other bytes can be added into receive queue.

An application might use SO_RCVLOWAT, poll() and/or ioctl( FIONREAD)
to efficiently use mmap()

On the sender side, MSG_EOR might help to clearly separate unaligned
headers and 4K-aligned chunks if necessary.

Tested:

mlx4 (cx-3) 40Gbit NIC, with tcp_mmap program provided in following patch.
MTU set to 4168  (4096 TCP payload, 40 bytes IPv6 header, 32 bytes TCP header)

Without mmap() (tcp_mmap -s)

received 32768 MB (0 % mmap'ed) in 8.13342 s, 33.7961 Gbit,
  cpu usage user:0.034 sys:3.778, 116.333 usec per MB, 63062 c-switches
received 32768 MB (0 % mmap'ed) in 8.14501 s, 33.748 Gbit,
  cpu usage user:0.029 sys:3.997, 122.864 usec per MB, 61903 c-switches
received 32768 MB (0 % mmap'ed) in 8.11723 s, 33.8635 Gbit,
  cpu usage user:0.048 sys:3.964, 122.437 usec per MB, 62983 c-switches
received 32768 MB (0 % mmap'ed) in 8.39189 s, 32.7552 Gbit,
  cpu usage user:0.038 sys:4.181, 128.754 usec per MB, 55834 c-switches

With mmap() on receiver (tcp_mmap -s -z)

received 32768 MB (100 % mmap'ed) in 8.03083 s, 34.2278 Gbit,
  cpu usage user:0.024 sys:1.466, 45.4712 usec per MB, 65479 c-switches
received 32768 MB (100 % mmap'ed) in 7.98805 s, 34.4111 Gbit,
  cpu usage user:0.026 sys:1.401, 43.5486 usec per MB, 65447 c-switches
received 32768 MB (100 % mmap'ed) in 7.98377 s, 34.4296 Gbit,
  cpu usage user:0.028 sys:1.452, 45.166 usec per MB, 65496 c-switches
received 32768 MB (99.9969 % mmap'ed) in 8.01838 s, 34.281 Gbit,
  cpu usage user:0.02 sys:1.446, 44.7388 usec per MB, 65505 c-switches

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-04-16 18:26:37 -04:00
Eric Dumazet 03f45c883c tcp: avoid extra wakeups for SO_RCVLOWAT users
SO_RCVLOWAT is properly handled in tcp_poll(), so that POLLIN is only
generated when enough bytes are available in receive queue, after
David change (commit c7004482e8 "tcp: Respect SO_RCVLOWAT in tcp_poll().")

But TCP still calls sk->sk_data_ready() for each chunk added in receive
queue, meaning thread is awaken, and goes back to sleep shortly after.

Tested:

tcp_mmap test program, receiving 32768 MB of data with SO_RCVLOWAT set to 512KB

-> Should get ~2 wakeups (c-switches) per MB, regardless of how many
(tiny or big) packets were received.

High speed (mostly full size GRO packets)

received 32768 MB (100 % mmap'ed) in 8.03112 s, 34.2266 Gbit,
  cpu usage user:0.037 sys:1.404, 43.9758 usec per MB, 65497 c-switches

received 32768 MB (99.9954 % mmap'ed) in 7.98453 s, 34.4263 Gbit,
  cpu usage user:0.03 sys:1.422, 44.3115 usec per MB, 65485 c-switches

Low speed (sender is ratelimited and sends 1-MSS at a time, so GRO is not helping)

received 22474.5 MB (100 % mmap'ed) in 6015.35 s, 0.0313414 Gbit,
  cpu usage user:0.05 sys:1.586, 72.7952 usec per MB, 44950 c-switches

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-04-16 18:26:37 -04:00
Eric Dumazet d1361840f8 tcp: fix SO_RCVLOWAT and RCVBUF autotuning
Applications might use SO_RCVLOWAT on TCP socket hoping to receive
one [E]POLLIN event only when a given amount of bytes are ready in socket
receive queue.

Problem is that receive autotuning is not aware of this constraint,
meaning sk_rcvbuf might be too small to allow all bytes to be stored.

Add a new (struct proto_ops)->set_rcvlowat method so that a protocol
can override the default setsockopt(SO_RCVLOWAT) behavior.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-04-16 18:26:37 -04:00
Eric Dumazet dcb8c9b437 tcp_bbr: better deal with suboptimal GSO (II)
This is second part of dealing with suboptimal device gso parameters.
In first patch (350c9f484b "tcp_bbr: better deal with suboptimal GSO")
we dealt with devices having low gso_max_segs

Some devices lower gso_max_size from 64KB to 16 KB (r8152 is an example)

In order to probe an optimal cwnd, we want BBR being not sensitive
to whatever GSO constraint a device can have.

This patch removes tso_segs_goal() CC callback in favor of
min_tso_segs() for CC wanting to override sysctl_tcp_min_tso_segs

Next patch will remove bbr->tso_segs_goal since it does not have
to be persistent.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-03-01 21:44:28 -05:00
Eric Dumazet e0f9759f53 tcp: try to keep packet if SYN_RCV race is lost
배석진 reported that in some situations, packets for a given 5-tuple
end up being processed by different CPUS.

This involves RPS, and fragmentation.

배석진 is seeing packet drops when a SYN_RECV request socket is
moved into ESTABLISH state. Other states are protected by socket lock.

This is caused by a CPU losing the race, and simply not caring enough.

Since this seems to occur frequently, we can do better and perform
a second lookup.

Note that all needed memory barriers are already in the existing code,
thanks to the spin_lock()/spin_unlock() pair in inet_ehash_insert()
and reqsk_put(). The second lookup must find the new socket,
unless it has already been accepted and closed by another cpu.

Note that the fragmentation could be avoided in the first place by
use of a correct TCP MSS option in the SYN{ACK} packet, but this
does not mean we can not be more robust.

Many thanks to 배석진 for a very detailed analysis.

Reported-by: 배석진 <soukjin.bae@samsung.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-02-14 14:21:45 -05:00
John Fastabend 1aa12bdf1b bpf: sockmap, add sock close() hook to remove socks
The selftests test_maps program was leaving dangling BPF sockmap
programs around because not all psock elements were removed from
the map. The elements in turn hold a reference on the BPF program
they are attached to causing BPF programs to stay open even after
test_maps has completed.

The original intent was that sk_state_change() would be called
when TCP socks went through TCP_CLOSE state. However, because
socks may be in SOCK_DEAD state or the sock may be a listening
socket the event is not always triggered.

To resolve this use the ULP infrastructure and register our own
proto close() handler. This fixes the above case.

Fixes: 174a79ff95 ("bpf: sockmap with sk redirect support")
Reported-by: Prashant Bhole <bhole_prashant_q7@lab.ntt.co.jp>
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-02-06 11:39:32 +01:00
John Fastabend b11a632c44 net: add a UID to use for ULP socket assignment
Create a UID field and enum that can be used to assign ULPs to
sockets. This saves a set of string comparisons if the ULP id
is known.

For sockmap, which is added in the next patches, a ULP is used to
hook into TCP sockets close state. In this case the ULP being added
is done at map insert time and the ULP is known and done on the kernel
side. In this case the named lookup is not needed. Because we don't
want to expose psock internals to user space socket options a user
visible flag is also added. For TLS this is set for BPF it will be
cleared.

Alos remove pr_notice, user gets an error code back and should check
that rather than rely on logs.

Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-02-06 11:39:31 +01:00
Linus Torvalds b2fe5fa686 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next
Pull networking updates from David Miller:

 1) Significantly shrink the core networking routing structures. Result
    of http://vger.kernel.org/~davem/seoul2017_netdev_keynote.pdf

 2) Add netdevsim driver for testing various offloads, from Jakub
    Kicinski.

 3) Support cross-chip FDB operations in DSA, from Vivien Didelot.

 4) Add a 2nd listener hash table for TCP, similar to what was done for
    UDP. From Martin KaFai Lau.

 5) Add eBPF based queue selection to tun, from Jason Wang.

 6) Lockless qdisc support, from John Fastabend.

 7) SCTP stream interleave support, from Xin Long.

 8) Smoother TCP receive autotuning, from Eric Dumazet.

 9) Lots of erspan tunneling enhancements, from William Tu.

10) Add true function call support to BPF, from Alexei Starovoitov.

11) Add explicit support for GRO HW offloading, from Michael Chan.

12) Support extack generation in more netlink subsystems. From Alexander
    Aring, Quentin Monnet, and Jakub Kicinski.

13) Add 1000BaseX, flow control, and EEE support to mvneta driver. From
    Russell King.

14) Add flow table abstraction to netfilter, from Pablo Neira Ayuso.

15) Many improvements and simplifications to the NFP driver bpf JIT,
    from Jakub Kicinski.

16) Support for ipv6 non-equal cost multipath routing, from Ido
    Schimmel.

17) Add resource abstration to devlink, from Arkadi Sharshevsky.

18) Packet scheduler classifier shared filter block support, from Jiri
    Pirko.

19) Avoid locking in act_csum, from Davide Caratti.

20) devinet_ioctl() simplifications from Al viro.

21) More TCP bpf improvements from Lawrence Brakmo.

22) Add support for onlink ipv6 route flag, similar to ipv4, from David
    Ahern.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1925 commits)
  tls: Add support for encryption using async offload accelerator
  ip6mr: fix stale iterator
  net/sched: kconfig: Remove blank help texts
  openvswitch: meter: Use 64-bit arithmetic instead of 32-bit
  tcp_nv: fix potential integer overflow in tcpnv_acked
  r8169: fix RTL8168EP take too long to complete driver initialization.
  qmi_wwan: Add support for Quectel EP06
  rtnetlink: enable IFLA_IF_NETNSID for RTM_NEWLINK
  ipmr: Fix ptrdiff_t print formatting
  ibmvnic: Wait for device response when changing MAC
  qlcnic: fix deadlock bug
  tcp: release sk_frag.page in tcp_disconnect
  ipv4: Get the address of interface correctly.
  net_sched: gen_estimator: fix lockdep splat
  net: macb: Handle HRESP error
  net/mlx5e: IPoIB, Fix copy-paste bug in flow steering refactoring
  ipv6: addrconf: break critical section in addrconf_verify_rtnl()
  ipv6: change route cache aging logic
  i40e/i40evf: Update DESC_NEEDED value to reflect larger value
  bnxt_en: cleanup DIM work on device shutdown
  ...
2018-01-31 14:31:10 -08:00
Linus Torvalds 168fe32a07 Merge branch 'misc.poll' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull poll annotations from Al Viro:
 "This introduces a __bitwise type for POLL### bitmap, and propagates
  the annotations through the tree. Most of that stuff is as simple as
  'make ->poll() instances return __poll_t and do the same to local
  variables used to hold the future return value'.

  Some of the obvious brainos found in process are fixed (e.g. POLLIN
  misspelled as POLL_IN). At that point the amount of sparse warnings is
  low and most of them are for genuine bugs - e.g. ->poll() instance
  deciding to return -EINVAL instead of a bitmap. I hadn't touched those
  in this series - it's large enough as it is.

  Another problem it has caught was eventpoll() ABI mess; select.c and
  eventpoll.c assumed that corresponding POLL### and EPOLL### were
  equal. That's true for some, but not all of them - EPOLL### are
  arch-independent, but POLL### are not.

  The last commit in this series separates userland POLL### values from
  the (now arch-independent) kernel-side ones, converting between them
  in the few places where they are copied to/from userland. AFAICS, this
  is the least disruptive fix preserving poll(2) ABI and making epoll()
  work on all architectures.

  As it is, it's simply broken on sparc - try to give it EPOLLWRNORM and
  it will trigger only on what would've triggered EPOLLWRBAND on other
  architectures. EPOLLWRBAND and EPOLLRDHUP, OTOH, are never triggered
  at all on sparc. With this patch they should work consistently on all
  architectures"

* 'misc.poll' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (37 commits)
  make kernel-side POLL... arch-independent
  eventpoll: no need to mask the result of epi_item_poll() again
  eventpoll: constify struct epoll_event pointers
  debugging printk in sg_poll() uses %x to print POLL... bitmap
  annotate poll(2) guts
  9p: untangle ->poll() mess
  ->si_band gets POLL... bitmap stored into a user-visible long field
  ring_buffer_poll_wait() return value used as return value of ->poll()
  the rest of drivers/*: annotate ->poll() instances
  media: annotate ->poll() instances
  fs: annotate ->poll() instances
  ipc, kernel, mm: annotate ->poll() instances
  net: annotate ->poll() instances
  apparmor: annotate ->poll() instances
  tomoyo: annotate ->poll() instances
  sound: annotate ->poll() instances
  acpi: annotate ->poll() instances
  crypto: annotate ->poll() instances
  block: annotate ->poll() instances
  x86: annotate ->poll() instances
  ...
2018-01-30 17:58:07 -08:00
Lawrence Brakmo de525be2ca bpf: Support passing args to sock_ops bpf function
Adds support for passing up to 4 arguments to sock_ops bpf functions. It
reusues the reply union, so the bpf_sock_ops structures are not
increased in size.

Signed-off-by: Lawrence Brakmo <brakmo@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-01-25 16:41:14 -08:00
Lawrence Brakmo b73042b8a2 bpf: Add write access to tcp_sock and sock fields
This patch adds a macro, SOCK_OPS_SET_FIELD, for writing to
struct tcp_sock or struct sock fields. This required adding a new
field "temp" to struct bpf_sock_ops_kern for temporary storage that
is used by sock_ops_convert_ctx_access. It is used to store and recover
the contents of a register, so the register can be used to store the
address of the sk. Since we cannot overwrite the dst_reg because it
contains the pointer to ctx, nor the src_reg since it contains the value
we want to store, we need an extra register to contain the address
of the sk.

Also adds the macro SOCK_OPS_GET_OR_SET_FIELD that calls one of the
GET or SET macros depending on the value of the TYPE field.

Signed-off-by: Lawrence Brakmo <brakmo@fb.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-01-25 16:41:14 -08:00
Yuchung Cheng e42866031f tcp: avoid min RTT bloat by skipping RTT from delayed-ACK in BBR
A persistent connection may send tiny amount of data (e.g. health-check)
for a long period of time. BBR's windowed min RTT filter may only see
RTT samples from delayed ACKs causing BBR to grossly over-estimate
the path delay depending how much the ACK was delayed at the receiver.

This patch skips RTT samples that are likely coming from delayed ACKs. Note
that it is possible the sender never obtains a valid measure to set the
min RTT. In this case BBR will continue to set cwnd to initial window
which seems fine because the connection is thin stream.

Signed-off-by: Yuchung Cheng <ycheng@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Acked-by: Priyaranjan Jha <priyarjha@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-19 15:39:30 -05:00
Yuchung Cheng 7268586baa 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 15:51:12 -05:00
David S. Miller 51e18a453f Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Conflict was two parallel additions of include files to sch_generic.c,
no biggie.

Signed-off-by: David S. Miller <davem@davemloft.net>
2017-12-09 22:09:55 -05:00
David S. Miller 62cd277039 Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Alexei Starovoitov says:

====================
pull-request: bpf-next 2017-12-07

The following pull-request contains BPF updates for your net-next tree.

The main changes are:

1) Detailed documentation of BPF development process from Daniel.

2) Addition of is_fullsock, snd_cwnd and srtt_us fields to bpf_sock_ops
   from Lawrence.

3) Minor follow up for bpf_skb_set_tunnel_key() from William.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
2017-12-08 10:48:25 -05:00
Yousuk Seung d4761754b4 tcp: invalidate rate samples during SACK reneging
Mark tcp_sock during a SACK reneging event and invalidate rate samples
while marked. Such rate samples may overestimate bw by including packets
that were SACKed before reneging.

< ack 6001 win 10000 sack 7001:38001
< ack 7001 win 0 sack 8001:38001 // Reneg detected
> seq 7001:8001 // RTO, SACK cleared.
< ack 38001 win 10000

In above example the rate sample taken after the last ack will count
7001-38001 as delivered while the actual delivery rate likely could
be much lower i.e. 7001-8001.

This patch adds a new field tcp_sock.sack_reneg and marks it when we
declare SACK reneging and entering TCP_CA_Loss, and unmarks it after
the last rate sample was taken before moving back to TCP_CA_Open. This
patch also invalidates rate samples taken while tcp_sock.is_sack_reneg
is set.

Fixes: b9f64820fb ("tcp: track data delivery rate for a TCP connection")
Signed-off-by: Yousuk Seung <ysseung@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Acked-by: Priyaranjan Jha <priyarjha@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-12-08 10:07:02 -05:00
Lawrence Brakmo f19397a5c6 bpf: Add access to snd_cwnd and others in sock_ops
Adds read access to snd_cwnd and srtt_us fields of tcp_sock. Since these
fields are only valid if the socket associated with the sock_ops program
call is a full socket, the field is_fullsock is also added to the
bpf_sock_ops struct. If the socket is not a full socket, reading these
fields returns 0.

Note that in most cases it will not be necessary to check is_fullsock to
know if there is a full socket. The context of the call, as specified by
the 'op' field, can sometimes determine whether there is a full socket.

The struct bpf_sock_ops has the following fields added:

  __u32 is_fullsock;      /* Some TCP fields are only valid if
                           * there is a full socket. If not, the
                           * fields read as zero.
			   */
  __u32 snd_cwnd;
  __u32 srtt_us;          /* Averaged RTT << 3 in usecs */

There is a new macro, SOCK_OPS_GET_TCP32(NAME), to make it easier to add
read access to more 32 bit tcp_sock fields.

Signed-off-by: Lawrence Brakmo <brakmo@fb.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2017-12-05 14:55:32 +01:00
David Ahern b4d1605a8e tcp: use IPCB instead of TCP_SKB_CB in inet_exact_dif_match()
After this fix : ("tcp: add tcp_v4_fill_cb()/tcp_v4_restore_cb()"),
socket lookups happen while skb->cb[] has not been mangled yet by TCP.

Fixes: a04a480d43 ("net: Require exact match for TCP socket lookups if dif is l3mdev")
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-12-03 12:39:15 -05:00
Al Viro ade994f4f6 net: annotate ->poll() instances
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-11-27 16:20:04 -05:00
Neal Cardwell ed66dfaf23 tcp: when scheduling TLP, time of RTO should account for current ACK
Fix the TLP scheduling logic so that when scheduling a TLP probe, we
ensure that the estimated time at which an RTO would fire accounts for
the fact that ACKs indicating forward progress should push back RTO
times.

After the following fix:

df92c8394e ("tcp: fix xmit timer to only be reset if data ACKed/SACKed")

we had an unintentional behavior change in the following kind of
scenario: suppose the RTT variance has been very low recently. Then
suppose we send out a flight of N packets and our RTT is 100ms:

t=0: send a flight of N packets
t=100ms: receive an ACK for N-1 packets

The response before df92c8394e that was:
  -> schedule a TLP for now + RTO_interval

The response after df92c8394e is:
  -> schedule a TLP for t=0 + RTO_interval

Since RTO_interval = srtt + RTT_variance, this means that we have
scheduled a TLP timer at a point in the future that only accounts for
RTT_variance. If the RTT_variance term is small, this means that the
timer fires soon.

Before df92c8394e this would not happen, because in that code, when
we receive an ACK for a prefix of flight, we did:

    1) Near the top of tcp_ack(), switch from TLP timer to RTO
       at write_queue_head->paket_tx_time + RTO_interval:
            if (icsk->icsk_pending == ICSK_TIME_LOSS_PROBE)
                   tcp_rearm_rto(sk);

    2) In tcp_clean_rtx_queue(), update the RTO to now + RTO_interval:
            if (flag & FLAG_ACKED) {
                   tcp_rearm_rto(sk);

    3) In tcp_ack() after tcp_fastretrans_alert() switch from RTO
       to TLP at now + RTO_interval:
            if (icsk->icsk_pending == ICSK_TIME_RETRANS)
                   tcp_schedule_loss_probe(sk);

In df92c8394e we removed that 3-phase dance, and instead directly
set the TLP timer once: we set the TLP timer in cases like this to
write_queue_head->packet_tx_time + RTO_interval. So if the RTT
variance is small, then this means that this is setting the TLP timer
to fire quite soon. This means if the ACK for the tail of the flight
takes longer than an RTT to arrive (often due to delayed ACKs), then
the TLP timer fires too quickly.

Fixes: df92c8394e ("tcp: fix xmit timer to only be reset if data ACKed/SACKed")
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
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>
2017-11-19 12:25:26 +09:00
Eric Dumazet 50895b9de1 tcp: highest_sack fix
syzbot easily found a regression added in our latest patches [1]

No longer set tp->highest_sack to the head of the send queue since
this is not logical and error prone.

Only sack processing should maintain the pointer to an skb from rtx queue.

We might in the future only remember the sequence instead of a pointer to skb,
since rb-tree should allow a fast lookup.

[1]
BUG: KASAN: use-after-free in tcp_highest_sack_seq include/net/tcp.h:1706 [inline]
BUG: KASAN: use-after-free in tcp_ack+0x42bb/0x4fd0 net/ipv4/tcp_input.c:3537
Read of size 4 at addr ffff8801c154faa8 by task syz-executor4/12860

CPU: 0 PID: 12860 Comm: syz-executor4 Not tainted 4.14.0-next-20171113+ #41
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x194/0x257 lib/dump_stack.c:53
 print_address_description+0x73/0x250 mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report+0x25b/0x340 mm/kasan/report.c:409
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:429
 tcp_highest_sack_seq include/net/tcp.h:1706 [inline]
 tcp_ack+0x42bb/0x4fd0 net/ipv4/tcp_input.c:3537
 tcp_rcv_established+0x672/0x18a0 net/ipv4/tcp_input.c:5439
 tcp_v4_do_rcv+0x2ab/0x7d0 net/ipv4/tcp_ipv4.c:1468
 sk_backlog_rcv include/net/sock.h:909 [inline]
 __release_sock+0x124/0x360 net/core/sock.c:2264
 release_sock+0xa4/0x2a0 net/core/sock.c:2778
 tcp_sendmsg+0x3a/0x50 net/ipv4/tcp.c:1462
 inet_sendmsg+0x11f/0x5e0 net/ipv4/af_inet.c:763
 sock_sendmsg_nosec net/socket.c:632 [inline]
 sock_sendmsg+0xca/0x110 net/socket.c:642
 ___sys_sendmsg+0x75b/0x8a0 net/socket.c:2048
 __sys_sendmsg+0xe5/0x210 net/socket.c:2082
 SYSC_sendmsg net/socket.c:2093 [inline]
 SyS_sendmsg+0x2d/0x50 net/socket.c:2089
 entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x452879
RSP: 002b:00007fc9761bfbe8 EFLAGS: 00000212 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000758020 RCX: 0000000000452879
RDX: 0000000000000000 RSI: 0000000020917fc8 RDI: 0000000000000015
RBP: 0000000000000086 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006ee3a0
R13: 00000000ffffffff R14: 00007fc9761c06d4 R15: 0000000000000000

Allocated by task 12860:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:551
 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:489
 kmem_cache_alloc_node+0x144/0x760 mm/slab.c:3638
 __alloc_skb+0xf1/0x780 net/core/skbuff.c:193
 alloc_skb_fclone include/linux/skbuff.h:1023 [inline]
 sk_stream_alloc_skb+0x11d/0x900 net/ipv4/tcp.c:870
 tcp_sendmsg_locked+0x1341/0x3b80 net/ipv4/tcp.c:1299
 tcp_sendmsg+0x2f/0x50 net/ipv4/tcp.c:1461
 inet_sendmsg+0x11f/0x5e0 net/ipv4/af_inet.c:763
 sock_sendmsg_nosec net/socket.c:632 [inline]
 sock_sendmsg+0xca/0x110 net/socket.c:642
 SYSC_sendto+0x358/0x5a0 net/socket.c:1749
 SyS_sendto+0x40/0x50 net/socket.c:1717
 entry_SYSCALL_64_fastpath+0x1f/0x96

Freed by task 12860:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0x71/0xc0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3492 [inline]
 kmem_cache_free+0x77/0x280 mm/slab.c:3750
 kfree_skbmem+0xdd/0x1d0 net/core/skbuff.c:603
 __kfree_skb+0x1d/0x20 net/core/skbuff.c:642
 sk_wmem_free_skb include/net/sock.h:1419 [inline]
 tcp_rtx_queue_unlink_and_free include/net/tcp.h:1682 [inline]
 tcp_clean_rtx_queue net/ipv4/tcp_input.c:3111 [inline]
 tcp_ack+0x1b17/0x4fd0 net/ipv4/tcp_input.c:3593
 tcp_rcv_established+0x672/0x18a0 net/ipv4/tcp_input.c:5439
 tcp_v4_do_rcv+0x2ab/0x7d0 net/ipv4/tcp_ipv4.c:1468
 sk_backlog_rcv include/net/sock.h:909 [inline]
 __release_sock+0x124/0x360 net/core/sock.c:2264
 release_sock+0xa4/0x2a0 net/core/sock.c:2778
 tcp_sendmsg+0x3a/0x50 net/ipv4/tcp.c:1462
 inet_sendmsg+0x11f/0x5e0 net/ipv4/af_inet.c:763
 sock_sendmsg_nosec net/socket.c:632 [inline]
 sock_sendmsg+0xca/0x110 net/socket.c:642
 ___sys_sendmsg+0x75b/0x8a0 net/socket.c:2048
 __sys_sendmsg+0xe5/0x210 net/socket.c:2082
 SYSC_sendmsg net/socket.c:2093 [inline]
 SyS_sendmsg+0x2d/0x50 net/socket.c:2089
 entry_SYSCALL_64_fastpath+0x1f/0x96

The buggy address belongs to the object at ffff8801c154fa80
 which belongs to the cache skbuff_fclone_cache of size 456
The buggy address is located 40 bytes inside of
 456-byte region [ffff8801c154fa80, ffff8801c154fc48)
The buggy address belongs to the page:
page:ffffea00070553c0 count:1 mapcount:0 mapping:ffff8801c154f080 index:0x0
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801c154f080 0000000000000000 0000000100000006
raw: ffffea00070a5a20 ffffea0006a18360 ffff8801d9ca0500 0000000000000000
page dumped because: kasan: bad access detected

Fixes: 737ff31456 ("tcp: use sequence distance to detect reordering")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-15 19:48:42 +09:00
Stephen Hemminger 6670e15244 tcp: Namespace-ify sysctl_tcp_default_congestion_control
Make default TCP default congestion control to a per namespace
value. This changes default congestion control to a pointer to congestion ops
(rather than implicit as first element of available lsit).

The congestion control setting of new namespaces is inherited
from the current setting of the root namespace.

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-15 14:09:52 +09:00
Yuchung Cheng 713bafea92 tcp: retire FACK loss detection
FACK loss detection has been disabled by default and the
successor RACK subsumed FACK and can handle reordering better.
This patch removes FACK to simplify TCP loss recovery.

Signed-off-by: Yuchung Cheng <ycheng@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Reviewed-by: Soheil Hassas Yeganeh <soheil@google.com>
Reviewed-by: Priyaranjan Jha <priyarjha@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-11 18:53:16 +09:00
Eric Dumazet 356d1833b6 tcp: Namespace-ify sysctl_tcp_rmem and sysctl_tcp_wmem
Note that when a new netns is created, it inherits its
sysctl_tcp_rmem and sysctl_tcp_wmem from initial netns.

This change is needed so that we can refine TCP rcvbuf autotuning,
to take RTT into consideration.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Wei Wang <weiwan@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-10 14:34:58 +09:00
Priyaranjan Jha 1f2556916d tcp: higher throughput under reordering with adaptive RACK reordering wnd
Currently TCP RACK loss detection does not work well if packets are
being reordered beyond its static reordering window (min_rtt/4).Under
such reordering it may falsely trigger loss recoveries and reduce TCP
throughput significantly.

This patch improves that by increasing and reducing the reordering
window based on DSACK, which is now supported in major TCP implementations.
It makes RACK's reo_wnd adaptive based on DSACK and no. of recoveries.

- If DSACK is received, increment reo_wnd by min_rtt/4 (upper bounded
  by srtt), since there is possibility that spurious retransmission was
  due to reordering delay longer than reo_wnd.

- Persist the current reo_wnd value for TCP_RACK_RECOVERY_THRESH (16)
  no. of successful recoveries (accounts for full DSACK-based loss
  recovery undo). After that, reset it to default (min_rtt/4).

- At max, reo_wnd is incremented only once per rtt. So that the new
  DSACK on which we are reacting, is due to the spurious retx (approx)
  after the reo_wnd has been updated last time.

- reo_wnd is tracked in terms of steps (of min_rtt/4), rather than
  absolute value to account for change in rtt.

In our internal testing, we observed significant increase in throughput,
in scenarios where reordering exceeds min_rtt/4 (previous static value).

Signed-off-by: Priyaranjan Jha <priyarjha@google.com>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-05 23:15:42 +09:00
David S. Miller ed29668d1a Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Smooth Cong Wang's bug fix into 'net-next'.  Basically put
the bulk of the tcf_block_put() logic from 'net' into
tcf_block_put_ext(), but after the offload unbind.

Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-02 15:23:39 +09:00
Eric Dumazet 2b7cda9c35 tcp: fix tcp_mtu_probe() vs highest_sack
Based on SNMP values provided by Roman, Yuchung made the observation
that some crashes in tcp_sacktag_walk() might be caused by MTU probing.

Looking at tcp_mtu_probe(), I found that when a new skb was placed
in front of the write queue, we were not updating tcp highest sack.

If one skb is freed because all its content was copied to the new skb
(for MTU probing), then tp->highest_sack could point to a now freed skb.

Bad things would then happen, including infinite loops.

This patch renames tcp_highest_sack_combine() and uses it
from tcp_mtu_probe() to fix the bug.

Note that I also removed one test against tp->sacked_out,
since we want to replace tp->highest_sack regardless of whatever
condition, since keeping a stale pointer to freed skb is a recipe
for disaster.

Fixes: a47e5a988a ("[TCP]: Convert highest_sack to sk_buff to allow direct access")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Reported-by: Roman Gushchin <guro@fb.com>
Reported-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-01 21:18:34 +09:00
David S. Miller e1ea2f9856 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Several conflicts here.

NFP driver bug fix adding nfp_netdev_is_nfp_repr() check to
nfp_fl_output() needed some adjustments because the code block is in
an else block now.

Parallel additions to net/pkt_cls.h and net/sch_generic.h

A bug fix in __tcp_retransmit_skb() conflicted with some of
the rbtree changes in net-next.

The tc action RCU callback fixes in 'net' had some overlap with some
of the recent tcf_block reworking.

Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-30 21:09:24 +09:00
John Fastabend 8108a77515 bpf: bpf_compute_data uses incorrect cb structure
SK_SKB program types use bpf_compute_data to store the end of the
packet data. However, bpf_compute_data assumes the cb is stored in the
qdisc layer format. But, for SK_SKB this is the wrong layer of the
stack for this type.

It happens to work (sort of!) because in most cases nothing happens
to be overwritten today. This is very fragile and error prone.
Fortunately, we have another hole in tcp_skb_cb we can use so lets
put the data_end value there.

Note, SK_SKB program types do not use data_meta, they are failed by
sk_skb_is_valid_access().

Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-29 11:18:48 +09:00
Alexei Starovoitov 5b52a4c3ac tcp: remove unnecessary include
two extra #include are not necessary in tcp.h
Remove them.

Fixes: 40304b2a15 ("bpf: BPF support for sock_ops")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-28 19:27:33 +09:00
Eric Dumazet c26e91f8b9 tcp: Namespace-ify sysctl_tcp_pacing_ca_ratio
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-28 19:24:39 +09:00
Eric Dumazet 23a7102a2d tcp: Namespace-ify sysctl_tcp_pacing_ss_ratio
Also remove an obsolete comment about TCP pacing.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-28 19:24:39 +09:00
Eric Dumazet 4170ba6b58 tcp: Namespace-ify sysctl_tcp_invalid_ratelimit
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-28 19:24:39 +09:00
Eric Dumazet 790f00e19f tcp: Namespace-ify sysctl_tcp_autocorking
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-28 19:24:39 +09:00
Eric Dumazet bd23970429 tcp: Namespace-ify sysctl_tcp_min_rtt_wlen
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-28 19:24:39 +09:00
Eric Dumazet 26e9596e5b tcp: Namespace-ify sysctl_tcp_min_tso_segs
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-28 19:24:38 +09:00
Eric Dumazet b530b68148 tcp: Namespace-ify sysctl_tcp_challenge_ack_limit
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-28 19:24:38 +09:00
Eric Dumazet 9184d8bb44 tcp: Namespace-ify sysctl_tcp_limit_output_bytes
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-28 19:24:38 +09:00
Eric Dumazet ceef9ab6be tcp: Namespace-ify sysctl_tcp_workaround_signed_windows
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-28 19:24:38 +09:00
Eric Dumazet d06a990458 tcp: Namespace-ify sysctl_tcp_tso_win_divisor
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-28 19:24:38 +09:00
Eric Dumazet 4540c0cf98 tcp: Namespace-ify sysctl_tcp_moderate_rcvbuf
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-28 19:24:38 +09:00
Eric Dumazet ec36e416f0 tcp: Namespace-ify sysctl_tcp_nometrics_save
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-28 19:24:38 +09:00
Eric Dumazet af9b69a7a6 tcp: Namespace-ify sysctl_tcp_frto
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-27 16:35:43 +09:00
Eric Dumazet 94f0893e0c tcp: Namespace-ify sysctl_tcp_adv_win_scale
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-27 16:35:43 +09:00
Eric Dumazet 0c12654ac6 tcp: Namespace-ify sysctl_tcp_app_win
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-27 16:35:43 +09:00
Eric Dumazet 6496f6bde0 tcp: Namespace-ify sysctl_tcp_dsack
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-27 16:35:43 +09:00
Eric Dumazet c6e2180359 tcp: Namespace-ify sysctl_tcp_max_reordering
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-27 16:35:43 +09:00
Eric Dumazet 773d4bb96c tcp: remove stale sysctl_tcp_reordering
This extern is no longer used.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-27 16:35:43 +09:00
Eric Dumazet 0bc65a28ae tcp: Namespace-ify sysctl_tcp_fack
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-27 16:35:42 +09:00
Eric Dumazet 65c9410cf5 tcp: Namespace-ify sysctl_tcp_abort_on_overflow
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-27 16:35:42 +09:00
Eric Dumazet 625357aa17 tcp: Namespace-ify sysctl_tcp_rfc1337
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-27 16:35:42 +09:00
Eric Dumazet 3f4c7c6f6a tcp: Namespace-ify sysctl_tcp_stdurg
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-27 16:35:42 +09:00
Eric Dumazet e0a1e5b519 tcp: Namespace-ify sysctl_tcp_retrans_collapse
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-27 16:35:42 +09:00
Eric Dumazet b510f0d23a tcp: Namespace-ify sysctl_tcp_slow_start_after_idle
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-27 16:35:42 +09:00
Eric Dumazet 2c04ac8ae0 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 16:35:42 +09:00