svn commit: r309397 - head/sys/netinet

[Michael Tuexen]

Author: tuexen
Date: Fri Dec  2 08:02:31 2016
New Revision: 309397
URL: https://svnweb.freebsd.org/changeset/base/309397

Log:
  Fix the handling of  TCP FIN-segments in the CLOSED state
  
  When a TCP segment with the FIN bit set was received in the CLOSED state,
  a TCP RST-ACK-segment is sent. When computing SEG.ACK for this, the
  FIN counts as one byte. This accounting was missing and is fixed by this
  patch.
  
  Reviewed by:		hiren
  MFC after:		1 month
  Sponsored by:		Netflix, Inc.
  Differential Revision:	https://svn.freebsd.org/base/head

Modified:
  head/sys/netinet/tcp_input.c

Modified: head/sys/netinet/tcp_input.c
==============================================================================
--- head/sys/netinet/tcp_input.c	Fri Dec  2 06:27:54 2016	(r309396)
+++ head/sys/netinet/tcp_input.c	Fri Dec  2 08:02:31 2016	(r309397)
@@ -3357,6 +3357,8 @@ tcp_dropwithreset(struct mbuf *m, struct
 	} else {
 		if (th->th_flags & TH_SYN)
 			tlen++;
+		if (th->th_flags & TH_FIN)
+			tlen++;
 		tcp_respond(tp, mtod(m, void *), th, m, th->th_seq+tlen,
 		    (tcp_seq)0, TH_RST|TH_ACK);
 	}