svn commit: r336167 - in head/sys/netinet: . tcp_stacks

[Michael Tuexen]

Author: tuexen
Date: Tue Jul 10 10:42:48 2018
New Revision: 336167
URL: https://svnweb.freebsd.org/changeset/base/336167

Log:
  Use appropriate MSS value when populating the TCP FO client cookie cache
  
  When a client receives a SYN-ACK segment with a TFP fast open cookie,
  but without an MSS option, an MSS value from uninitialised stack memory is used.
  This patch ensures that in case no MSS option is included in the SYN-ACK,
  the appropriate value as given in RFC 7413 is used.
  
  Reviewed by:		kbowling@
  Sponsored by:		Netflix, Inc.
  Differential Revision:	https://reviews.freebsd.org/D16175

Modified:
  head/sys/netinet/tcp_input.c
  head/sys/netinet/tcp_stacks/fastpath.c
  head/sys/netinet/tcp_stacks/rack.c

Modified: head/sys/netinet/tcp_input.c
==============================================================================
--- head/sys/netinet/tcp_input.c	Tue Jul 10 09:49:27 2018	(r336166)
+++ head/sys/netinet/tcp_input.c	Tue Jul 10 10:42:48 2018	(r336167)
@@ -1674,10 +1674,19 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th, stru
 		    (to.to_flags & TOF_SACKPERM) == 0)
 			tp->t_flags &= ~TF_SACK_PERMIT;
 		if (IS_FASTOPEN(tp->t_flags)) {
-			if (to.to_flags & TOF_FASTOPEN)
-				tcp_fastopen_update_cache(tp, to.to_mss,
+			if (to.to_flags & TOF_FASTOPEN) {
+				uint16_t mss;
+
+				if (to.to_flags & TOF_MSS)
+					mss = to.to_mss;
+				else
+					if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0)
+						mss = TCP6_MSS;
+					else
+						mss = TCP_MSS;
+				tcp_fastopen_update_cache(tp, mss,
 				    to.to_tfo_len, to.to_tfo_cookie);
-			else
+			} else
 				tcp_fastopen_disable_path(tp);
 		}
 	}

Modified: head/sys/netinet/tcp_stacks/fastpath.c
==============================================================================
--- head/sys/netinet/tcp_stacks/fastpath.c	Tue Jul 10 09:49:27 2018	(r336166)
+++ head/sys/netinet/tcp_stacks/fastpath.c	Tue Jul 10 10:42:48 2018	(r336167)
@@ -1763,10 +1763,19 @@ tcp_do_segment_fastslow(struct mbuf *m, struct tcphdr 
 		    (to.to_flags & TOF_SACKPERM) == 0)
 			tp->t_flags &= ~TF_SACK_PERMIT;
 		if (IS_FASTOPEN(tp->t_flags)) {
-			if (to.to_flags & TOF_FASTOPEN)
-				tcp_fastopen_update_cache(tp, to.to_mss,
+			if (to.to_flags & TOF_FASTOPEN) {
+				uint16_t mss;
+
+				if (to.to_flags & TOF_MSS)
+					mss = to.to_mss;
+				else
+					if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0)
+						mss = TCP6_MSS;
+					else
+						mss = TCP_MSS;
+				tcp_fastopen_update_cache(tp, mss,
 				    to.to_tfo_len, to.to_tfo_cookie);
-			else
+			} else
 				tcp_fastopen_disable_path(tp);
 		}
 	}
@@ -2220,10 +2229,19 @@ tcp_do_segment_fastack(struct mbuf *m, struct tcphdr *
 		    (to.to_flags & TOF_SACKPERM) == 0)
 			tp->t_flags &= ~TF_SACK_PERMIT;
 		if (IS_FASTOPEN(tp->t_flags)) {
-			if (to.to_flags & TOF_FASTOPEN)
-				tcp_fastopen_update_cache(tp, to.to_mss,
+			if (to.to_flags & TOF_FASTOPEN) {
+				uint16_t mss;
+
+				if (to.to_flags & TOF_MSS)
+					mss = to.to_mss;
+				else
+					if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0)
+						mss = TCP6_MSS;
+					else
+						mss = TCP_MSS;
+				tcp_fastopen_update_cache(tp, mss,
 				    to.to_tfo_len, to.to_tfo_cookie);
-			else
+			} else
 				tcp_fastopen_disable_path(tp);
 		}
 	}

Modified: head/sys/netinet/tcp_stacks/rack.c
==============================================================================
--- head/sys/netinet/tcp_stacks/rack.c	Tue Jul 10 09:49:27 2018	(r336166)
+++ head/sys/netinet/tcp_stacks/rack.c	Tue Jul 10 10:42:48 2018	(r336167)
@@ -6657,10 +6657,19 @@ rack_hpts_do_segment(struct mbuf *m, struct tcphdr *th
 			    (to.to_flags & TOF_SACKPERM) == 0)
 				tp->t_flags &= ~TF_SACK_PERMIT;
 			if (IS_FASTOPEN(tp->t_flags)) {
-				if (to.to_flags & TOF_FASTOPEN)
-					tcp_fastopen_update_cache(tp, to.to_mss,
+				if (to.to_flags & TOF_FASTOPEN) {
+					uint16_t mss;
+
+					if (to.to_flags & TOF_MSS)
+						mss = to.to_mss;
+					else
+						if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0)
+							mss = TCP6_MSS;
+						else
+							mss = TCP_MSS;
+					tcp_fastopen_update_cache(tp, mss,
 					    to.to_tfo_len, to.to_tfo_cookie);
-				else
+				} else
 					tcp_fastopen_disable_path(tp);
 			}
 		}