git: 2593f858d7d0 - main - A TCP server has to take into consideration, if TCP_NOOPT is preventing the negotiation of TCP features. This affects most TCP options but adherance to RFC7323 with the timestamp option will prevent a session from getting established.

[Richard Scheffenegger]

The branch main has been updated by rscheff:

URL: https://cgit.FreeBSD.org/src/commit/?id=2593f858d7d078efa85f78f20b6bfa0931cc1dc5

commit 2593f858d7d078efa85f78f20b6bfa0931cc1dc5
Author:     Richard Scheffenegger <rscheff at FreeBSD.org>
AuthorDate: 2021-02-25 18:10:55 +0000
Commit:     Richard Scheffenegger <rscheff at FreeBSD.org>
CommitDate: 2021-02-25 18:12:20 +0000

    A TCP server has to take into consideration, if TCP_NOOPT is preventing
    the negotiation of TCP features. This affects most TCP options but
    adherance to RFC7323 with the timestamp option will prevent a session
    from getting established.
    
    PR:     253576
    Reviewed By:    tuexen, #transport
    MFC after:      3 days
    Sponsored by:   NetApp, Inc.
    Differential Revision: https://reviews.freebsd.org/D28652
---
 sys/netinet/tcp_input.c    | 12 ++++++++----
 sys/netinet/tcp_syncache.c |  3 ++-
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/sys/netinet/tcp_input.c b/sys/netinet/tcp_input.c
index bbc93a93810c..6338b7491a7f 100644
--- a/sys/netinet/tcp_input.c
+++ b/sys/netinet/tcp_input.c
@@ -1644,7 +1644,8 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so,
 			TCPSTAT_INC(tcps_ecn_shs);
 		}
 		if ((to.to_flags & TOF_SCALE) &&
-		    (tp->t_flags & TF_REQ_SCALE)) {
+		    (tp->t_flags & TF_REQ_SCALE) &&
+		    !(tp->t_flags & TF_NOOPT)) {
 			tp->t_flags |= TF_RCVD_SCALE;
 			tp->snd_scale = to.to_wscale;
 		} else
@@ -1655,7 +1656,8 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so,
 		 */
 		tp->snd_wnd = th->th_win;
 		if ((to.to_flags & TOF_TS) &&
-		    (tp->t_flags & TF_REQ_TSTMP)) {
+		    (tp->t_flags & TF_REQ_TSTMP) &&
+		    !(tp->t_flags & TF_NOOPT)) {
 			tp->t_flags |= TF_RCVD_TSTMP;
 			tp->ts_recent = to.to_tsval;
 			tp->ts_recent_age = tcp_ts_getticks();
@@ -1664,10 +1666,12 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so,
 		if (to.to_flags & TOF_MSS)
 			tcp_mss(tp, to.to_mss);
 		if ((tp->t_flags & TF_SACK_PERMIT) &&
-		    (to.to_flags & TOF_SACKPERM) == 0)
+		    (!(to.to_flags & TOF_SACKPERM) ||
+		    (tp->t_flags & TF_NOOPT)))
 			tp->t_flags &= ~TF_SACK_PERMIT;
 		if (IS_FASTOPEN(tp->t_flags)) {
-			if (to.to_flags & TOF_FASTOPEN) {
+			if ((to.to_flags & TOF_FASTOPEN) &&
+			    !(tp->t_flags & TF_NOOPT)) {
 				uint16_t mss;
 
 				if (to.to_flags & TOF_MSS)
diff --git a/sys/netinet/tcp_syncache.c b/sys/netinet/tcp_syncache.c
index e59a41fc1102..771ff44b8924 100644
--- a/sys/netinet/tcp_syncache.c
+++ b/sys/netinet/tcp_syncache.c
@@ -1655,7 +1655,8 @@ skip_alloc:
 	win = imin(win, TCP_MAXWIN);
 	sc->sc_wnd = win;
 
-	if (V_tcp_do_rfc1323) {
+	if (V_tcp_do_rfc1323 &&
+	    !(ltflags & TF_NOOPT)) {
 		/*
 		 * A timestamp received in a SYN makes
 		 * it ok to send timestamp requests and replies.