This patch implements sending SYN-data in tcp_connect(). The data is
from tcp_sendmsg() with flag MSG_FASTOPEN (implemented in a later patch).
The length of the cookie in tcp_fastopen_req, init'd to 0, controls the
type of the SYN. If the cookie is not cached (len==0), the host sends
data-less SYN with Fast Open cookie request option to solicit a cookie
from the remote. If cookie is not available (len > 0), the host sends
a SYN-data with Fast Open cookie option. If cookie length is negative,
the SYN will not include any Fast Open option (for fall back operations).
To deal with middleboxes that may drop SYN with data or experimental TCP
option, the SYN-data is only sent once. SYN retransmits do not include
data or Fast Open options. The connection will fall back to regular TCP
handshake.
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Implement the RFC 5691 mitigation against Blind
Reset attack using SYN bit.
Section 4.2 of RFC 5961 advises to send a Challenge ACK and drop
incoming packet, instead of resetting the session.
Add a new SNMP counter to count number of challenge acks sent
in response to SYN packets.
(netstat -s | grep TCPSYNChallenge)
Remove obsolete TCPAbortOnSyn, since we no longer abort a TCP session
because of a SYN flag.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Kiran Kumar Kella <kkiran@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Implement the RFC 5691 mitigation against Blind
Reset attack using RST bit.
Idea is to validate incoming RST sequence,
to match RCV.NXT value, instead of previouly accepted
window : (RCV.NXT <= SEG.SEQ < RCV.NXT+RCV.WND)
If sequence is in window but not an exact match, send
a "challenge ACK", so that the other part can resend an
RST with the appropriate sequence.
Add a new sysctl, tcp_challenge_ack_limit, to limit
number of challenge ACK sent per second.
Add a new SNMP counter to count number of challenge acks sent.
(netstat -s | grep TCPChallengeACK)
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Kiran Kumar Kella <kkiran@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add three SNMP TCP counters, to better track TCP behavior
at global stage (netstat -s), when packets are received
Out Of Order (OFO)
TCPOFOQueue : Number of packets queued in OFO queue
TCPOFODrop : Number of packets meant to be queued in OFO
but dropped because socket rcvbuf limit hit.
TCPOFOMerge : Number of packets in OFO that were merged with
other packets.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
With increasing receive window sizes, but speed of light not improved
that much, out of order queue can contain a huge number of skbs, waiting
to be moved to receive_queue when missing packets can fill the holes.
Some devices happen to use fat skbs (truesize of 4096 + sizeof(struct
sk_buff)) to store regular (MTU <= 1500) frames. This makes highly
probable sk_rmem_alloc hits sk_rcvbuf limit, which can be 4Mbytes in
many cases.
When limit is hit, tcp stack calls tcp_collapse_ofo_queue(), a true
latency killer and cpu cache blower.
Doing the coalescing attempt each time we add a frame in ofo queue
permits to keep memory use tight and in many cases avoid the
tcp_collapse() thing later.
Tested on various wireless setups (b43, ath9k, ...) known to use big skb
truesize, this patch removed the "packets collapsed in receive queue due
to low socket buffer" I had before.
This also reduced average memory used by tcp sockets.
With help from Neal Cardwell.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: H.K. Jerry Chu <hkchu@google.com>
Cc: Tom Herbert <therbert@google.com>
Cc: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
It might be useful to get a counter of failed tcp_retransmit_skb()
calls.
Reported-by: Satoru Moriya <satoru.moriya@hds.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Correctly implement a loss detection heuristic: New sequences (above
high_seq) sent during the fast recovery are deemed lost when higher
sequences are SACKed.
Current code does not catch these losses, because tcp_mark_head_lost()
does not check packets beyond high_seq. The fix is straight-forward by
checking packets until the highest sacked packet. In addition, all the
FLAG_DATA_LOST logic are in-effective and redundant and can be removed.
Update the loss heuristic comments. The algorithm above is documented
as heuristic B, but it is redundant too because heuristic A already
covers B.
Note that this change only marks some forward-retransmitted packets LOST.
It does NOT forbid TCP performing further CWR on new losses. A potential
follow-up patch under preparation is to perform another CWR on "new"
losses such as
1) sequence above high_seq is lost (by resetting high_seq to snd_nxt)
2) retransmission is lost.
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
"Possible SYN flooding on port xxxx " messages can fill logs on servers.
Change logic to log the message only once per listener, and add two new
SNMP counters to track :
TCPReqQFullDoCookies : number of times a SYNCOOKIE was replied to client
TCPReqQFullDrop : number of times a SYN request was dropped because
syncookies were not enabled.
Based on a prior patch from Tom Herbert, and suggestions from David.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Rather than printing the message to the log, use a mib counter to keep
track of the count of occurences of time wait bucket overflow. Reduces
spam in logs.
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Christoph Lameter mentioned that packets could be dropped in input path
because of rp_filter settings, without any SNMP counter being
incremented. System administrator can have a hard time to track the
problem.
This patch introduces a new counter, LINUX_MIB_IPRPFILTER, incremented
each time we drop a packet because Reverse Path Filter triggers.
(We receive an IPv4 datagram on a given interface, and find the route to
send an answer would use another interface)
netstat -s | grep IPReversePathFilter
IPReversePathFilter: 21714
Reported-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When ip_append() fails because of socket limit or memory shortage,
increment ICMP_MIB_OUTERRORS counter, so that "netstat -s" can report
these errors.
LANG=C netstat -s | grep "ICMP messages failed"
0 ICMP messages failed
For IPV6, implement ICMP6_MIB_OUTERRORS counter as well.
# grep Icmp6OutErrors /proc/net/dev_snmp6/*
/proc/net/dev_snmp6/eth0:Icmp6OutErrors 0
/proc/net/dev_snmp6/lo:Icmp6OutErrors 0
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Its currently hard to diagnose when ACK frames are dropped because an
application set TCP_DEFER_ACCEPT on its listening socket.
See http://bugzilla.kernel.org/show_bug.cgi?id=15507
This patch adds a SNMP value, named TCPDeferAcceptDrop
netstat -s | grep TCPDeferAcceptDrop
TCPDeferAcceptDrop: 0
This counter is incremented every time we drop a pure ACK frame received
by a socket in SYN_RECV state because its SYNACK retrans count is lower
than defer_accept value.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit 6b03a53a (tcp: use limited socket backlog) added the possibility
of dropping frames when backlog queue is full.
Commit d218d111 (tcp: Generalized TTL Security Mechanism) added the
possibility of dropping frames when TTL is under a given limit.
This patch adds new SNMP MIB entries, named TCPBacklogDrop and
TCPMinTTLDrop, published in /proc/net/netstat in TcpExt: line
netstat -s | egrep "TCPBacklogDrop|TCPMinTTLDrop"
TCPBacklogDrop: 0
TCPMinTTLDrop: 0
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
XFRMINHDRERROR counter is ambigous when validating forwarding
path. It makes it tricky to debug when you have both in and fwd
validation.
Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>
The IP MIB (RFC 4293) defines stats for InOctets, OutOctets, InMcastOctets and
OutMcastOctets:
http://tools.ietf.org/html/rfc4293
But it seems we don't track those in any way that easy to separate from other
protocols. This patch adds those missing counters to the stats file. Tested
successfully by me
With help from Eric Dumazet.
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
o Outbound sequence number overflow error status
is counted as XfrmOutStateSeqError.
o Additionaly, it changes inbound sequence number replay
error name from XfrmInSeqOutOfWindow to XfrmInStateSeqError
to apply name scheme above.
o Inbound IPv4 UDP encapsuling type mismatch error is wrongly
mapped to XfrmInStateInvalid then this patch fiex the error
to XfrmInStateMismatch.
Signed-off-by: Masahide NAKAMURA <nakam@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This statistics is shown factor dropped by transformation
at /proc/net/xfrm_stat for developer.
It is a counter designed from current transformation source code
and defined as linux private MIB.
See Documentation/networking/xfrm_proc.txt for the detail.
Signed-off-by: Masahide NAKAMURA <nakam@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Background: RFC 4293 deprecates existing individual, named ICMP
type counters to be replaced with the ICMPMsgStatsTable. This table
includes entries for both IPv4 and IPv6, and requires counting of all
ICMP types, whether or not the machine implements the type.
These patches "remove" (but not really) the existing counters, and
replace them with the ICMPMsgStats tables for v4 and v6.
It includes the named counters in the /proc places they were, but gets the
values for them from the new tables. It also counts packets generated
from raw socket output (e.g., OutEchoes, MLD queries, RA's from
radvd, etc).
Changes:
1) create icmpmsg_statistics mib
2) create icmpv6msg_statistics mib
3) modify existing counters to use these
4) modify /proc/net/snmp to add "IcmpMsg" with all ICMP types
listed by number for easy SNMP parsing
5) modify /proc/net/snmp printing for "Icmp" to get the named data
from new counters.
Signed-off-by: David L Stevens <dlstevens@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Background: RFC 4293 deprecates existing individual, named ICMP
type counters to be replaced with the ICMPMsgStatsTable. This table
includes entries for both IPv4 and IPv6, and requires counting of all
ICMP types, whether or not the machine implements the type.
These patches "remove" (but not really) the existing counters, and
replace them with the ICMPMsgStats tables for v4 and v6.
It includes the named counters in the /proc places they were, but gets the
values for them from the new tables. It also counts packets generated
from raw socket output (e.g., OutEchoes, MLD queries, RA's from
radvd, etc).
Changes:
1) create icmpmsg_statistics mib
2) create icmpv6msg_statistics mib
3) modify existing counters to use these
4) modify /proc/net/snmp to add "IcmpMsg" with all ICMP types
listed by number for easy SNMP parsing
5) modify /proc/net/snmp printing for "Icmp" to get the named data
from new counters.
[new to 2nd revision]
6) support per-interface ICMP stats
7) use common macro for per-device stat macros
Signed-off-by: David L Stevens <dlstevens@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In DSACK case, some events are not extraordinary, such as packet
duplication generated DSACK. They can arrive easily below
snd_una when undo_marker is not set (TCP being in CA_Open),
counting such DSACKs amoung SACK discards will likely just
mislead if they occur in some scenario when there are other
problems as well. Similarly, excessively delayed packets could
cause "normal" DSACKs. Therefore, separate counters are
allocated for DSACK events.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
The updated IP-MIB RFC (RFC4293) specifys new objects, InBcastPkts
and OutBcastPkts. This adds definitions for them.
Signed-off-by: Mitsuru Chinen <mitch@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch adds more statistics info under /proc/net/sctp/snmp
that should be useful for debugging. The additional events that
are counted now include timer expirations, retransmits, packet
and data chunk discards.
The Data chunk discards include all the cases where a data chunk
is discarded including high tsn, bad stream, dup tsn and the most
useful one(out of receive buffer/rwnd).
Also moved the SCTP MIB data structures from the generic include
directories to include/sctp/sctp.h.
Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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!
Yuchung Cheng