svn commit: r322812 - head/sys/netinet

[Michael Tuexen]

Author: tuexen
Date: Wed Aug 23 14:50:08 2017
New Revision: 322812
URL: https://svnweb.freebsd.org/changeset/base/322812

Log:
  Avoid TCP log messages which are false positives.
  
  The check for timestamps are too early to handle SYN-ACK correctly.
  So move it down after the corresponing processing has been done.
  
  PR:		216832
  Obtained from:	antonfb at hesiod.org
  MFC after:	1 week

Modified:
  head/sys/netinet/tcp_input.c

Modified: head/sys/netinet/tcp_input.c
==============================================================================
--- head/sys/netinet/tcp_input.c	Wed Aug 23 12:47:10 2017	(r322811)
+++ head/sys/netinet/tcp_input.c	Wed Aug 23 14:50:08 2017	(r322812)
@@ -1694,25 +1694,6 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th, stru
 			to.to_tsecr = 0;
 	}
 	/*
-	 * If timestamps were negotiated during SYN/ACK they should
-	 * appear on every segment during this session and vice versa.
-	 */
-	if ((tp->t_flags & TF_RCVD_TSTMP) && !(to.to_flags & TOF_TS)) {
-		if ((s = tcp_log_addrs(inc, th, NULL, NULL))) {
-			log(LOG_DEBUG, "%s; %s: Timestamp missing, "
-			    "no action\n", s, __func__);
-			free(s, M_TCPLOG);
-		}
-	}
-	if (!(tp->t_flags & TF_RCVD_TSTMP) && (to.to_flags & TOF_TS)) {
-		if ((s = tcp_log_addrs(inc, th, NULL, NULL))) {
-			log(LOG_DEBUG, "%s; %s: Timestamp not expected, "
-			    "no action\n", s, __func__);
-			free(s, M_TCPLOG);
-		}
-	}
-
-	/*
 	 * Process options only when we get SYN/ACK back. The SYN case
 	 * for incoming connections is handled in tcp_syncache.
 	 * According to RFC1323 the window field in a SYN (i.e., a <SYN>
@@ -1740,6 +1721,25 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th, stru
 		if ((tp->t_flags & TF_SACK_PERMIT) &&
 		    (to.to_flags & TOF_SACKPERM) == 0)
 			tp->t_flags &= ~TF_SACK_PERMIT;
+	}
+
+	/*
+	 * If timestamps were negotiated during SYN/ACK they should
+	 * appear on every segment during this session and vice versa.
+	 */
+	if ((tp->t_flags & TF_RCVD_TSTMP) && !(to.to_flags & TOF_TS)) {
+		if ((s = tcp_log_addrs(inc, th, NULL, NULL))) {
+			log(LOG_DEBUG, "%s; %s: Timestamp missing, "
+			    "no action\n", s, __func__);
+			free(s, M_TCPLOG);
+		}
+	}
+	if (!(tp->t_flags & TF_RCVD_TSTMP) && (to.to_flags & TOF_TS)) {
+		if ((s = tcp_log_addrs(inc, th, NULL, NULL))) {
+			log(LOG_DEBUG, "%s; %s: Timestamp not expected, "
+			    "no action\n", s, __func__);
+			free(s, M_TCPLOG);
+		}
 	}
 
 	/*