svn commit: r324181 - head/sys/netinet

[Patrick Kelsey]

Author: pkelsey
Date: Sun Oct  1 23:37:17 2017
New Revision: 324181
URL: https://svnweb.freebsd.org/changeset/base/324181

Log:
  The soisconnected() call removed from syncache_socket() in r307966 was
  not extraneous in the TCP Fast Open (TFO) passive-open case.  In the
  TFO passive-open case, syncache_socket() is being called during
  processing of a TFO SYN bearing a valid cookie, and a call to
  soisconnected() is required in order to allow the application to
  immediately consume any data delivered in the SYN and to have a chance
  to generate response data to accompany the SYN-ACK.  The removal of
  this call to soisconnected() effectively converted all TFO passive
  opens to having the same RTT cost as a standard 3WHS.
  
  This commit adds a call to soisconnected() to syncache_tfo_expand() so
  that it is only in the TFO passive-open path, thereby restoring TFO
  passve-open RTT performance and preserving the non-TFO connection-rate
  performance gains realized by r307966.
  
  MFC after:	1 week
  Sponsored by:	Limelight Networks

Modified:
  head/sys/netinet/tcp_syncache.c

Modified: head/sys/netinet/tcp_syncache.c
==============================================================================
--- head/sys/netinet/tcp_syncache.c	Sun Oct  1 21:45:15 2017	(r324180)
+++ head/sys/netinet/tcp_syncache.c	Sun Oct  1 23:37:17 2017	(r324181)
@@ -1195,6 +1195,7 @@ syncache_tfo_expand(struct syncache *sc, struct socket
 		TCPSTAT_INC(tcps_sc_aborted);
 		atomic_subtract_int(pending_counter, 1);
 	} else {
+		soisconnected(*lsop);
 		inp = sotoinpcb(*lsop);
 		tp = intotcpcb(inp);
 		tp->t_flags |= TF_FASTOPEN;