linux/net/dccp
Eric Dumazet e6c022a4fa tcp: better retrans tracking for defer-accept
For passive TCP connections using TCP_DEFER_ACCEPT facility,
we incorrectly increment req->retrans each time timeout triggers
while no SYNACK is sent.

SYNACK are not sent for TCP_DEFER_ACCEPT that were established (for
which we received the ACK from client). Only the last SYNACK is sent
so that we can receive again an ACK from client, to move the req into
accept queue. We plan to change this later to avoid the useless
retransmit (and potential problem as this SYNACK could be lost)

TCP_INFO later gives wrong information to user, claiming imaginary
retransmits.

Decouple req->retrans field into two independent fields :

num_retrans : number of retransmit
num_timeout : number of timeouts

num_timeout is the counter that is incremented at each timeout,
regardless of actual SYNACK being sent or not, and used to
compute the exponential timeout.

Introduce inet_rtx_syn_ack() helper to increment num_retrans
only if ->rtx_syn_ack() succeeded.

Use inet_rtx_syn_ack() from tcp_check_req() to increment num_retrans
when we re-send a SYNACK in answer to a (retransmitted) SYN.
Prior to this patch, we were not counting these retransmits.

Change tcp_v[46]_rtx_synack() to increment TCP_MIB_RETRANSSEGS
only if a synack packet was successfully queued.

Reported-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Julian Anastasov <ja@ssi.bg>
Cc: Vijay Subramanian <subramanian.vijay@gmail.com>
Cc: Elliott Hughes <enh@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-11-03 14:45:00 -04:00
..
ccids dccp: fix info leak via getsockopt(DCCP_SOCKOPT_CCID_TX_INFO) 2012-08-15 21:36:31 -07:00
Kconfig Docs/Kconfig: Update: osdl.org -> linuxfoundation.org 2010-11-15 23:50:13 +01:00
Makefile dccp: Policy-based packet dequeueing infrastructure 2010-12-07 13:47:12 +01:00
ackvec.c net: Add export.h for EXPORT_SYMBOL/THIS_MODULE to non-modules 2011-10-31 19:30:30 -04:00
ackvec.h net: Fix (nearly-)kernel-doc comments for various functions 2012-07-10 23:13:45 -07:00
ccid.c net: Fix (nearly-)kernel-doc comments for various functions 2012-07-10 23:13:45 -07:00
ccid.h dccp: check ccid before dereferencing 2012-08-15 21:36:31 -07:00
dccp.h net: Fix (nearly-)kernel-doc comments for various functions 2012-07-10 23:13:45 -07:00
diag.c inet_diag: Rename inet_diag_req into inet_diag_req_v2 2012-01-11 12:56:06 -08:00
feat.c net: Fix (nearly-)kernel-doc comments for various functions 2012-07-10 23:13:45 -07:00
feat.h dccp: support for the exchange of NN options in established state 1/2 2011-08-01 07:52:34 -06:00
input.c net: Fix (nearly-)kernel-doc comments for various functions 2012-07-10 23:13:45 -07:00
ipv4.c ipv4: Prepare for change of rt->rt_iif encoding. 2012-07-23 16:36:26 -07:00
ipv6.c net: Pass optional SKB and SK arguments to dst_ops->{update_pmtu,redirect}() 2012-07-17 03:29:28 -07:00
ipv6.h Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
minisocks.c tcp: better retrans tracking for defer-accept 2012-11-03 14:45:00 -04:00
options.c net: Fix (nearly-)kernel-doc comments for various functions 2012-07-10 23:13:45 -07:00
output.c net: Fix (nearly-)kernel-doc comments for various functions 2012-07-10 23:13:45 -07:00
probe.c dccp: Fix compile warning in probe code. 2011-12-01 14:45:49 -05:00
proto.c net: include/net/sock.h cleanup 2012-05-17 04:50:21 -04:00
qpolicy.c dccp qpolicy: Parameter checking of cmsg qpolicy parameters 2010-12-07 13:47:12 +01:00
sysctl.c net: Convert all sysctl registrations to register_net_sysctl 2012-04-20 21:22:30 -04:00
timer.c net: Add export.h for EXPORT_SYMBOL/THIS_MODULE to non-modules 2011-10-31 19:30:30 -04:00