git: e99fa57b981e - stable/13 - tcp: Fix an issue with the PUSH bit as well as fill in the missing mtu change for fsb's

[Michael Tuexen]

The branch stable/13 has been updated by tuexen:

URL: https://cgit.FreeBSD.org/src/commit/?id=e99fa57b981eaeac287a1d0d8c0b351740f7a30b

commit e99fa57b981eaeac287a1d0d8c0b351740f7a30b
Author:     Randall Stewart <rrs at FreeBSD.org>
AuthorDate: 2021-05-24 18:42:15 +0000
Commit:     Michael Tuexen <tuexen at FreeBSD.org>
CommitDate: 2021-06-09 00:12:21 +0000

    tcp: Fix an issue with the PUSH bit as well as fill in the missing mtu change for fsb's
    
    The push bit itself was also not actually being properly moved to
    the right edge. The FIN bit was incorrectly on the left edge. We
    fix these two issues as well as plumb in the mtu_change for
    alternate stacks.
    
    Reviewed by: mtuexen
    Sponsored by: Netflix Inc
    Differential Revision:  https://reviews.freebsd.org/D30413
    
    (cherry picked from commit 631449d5d03506295eaa6947c1b0e8a168a2f6b7)
---
 sys/netinet/tcp_stacks/rack.c | 8 ++++++--
 sys/netinet/tcp_subr.c        | 9 +++++++++
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/sys/netinet/tcp_stacks/rack.c b/sys/netinet/tcp_stacks/rack.c
index c870b286a847..0bdcc20d2b7c 100644
--- a/sys/netinet/tcp_stacks/rack.c
+++ b/sys/netinet/tcp_stacks/rack.c
@@ -6058,8 +6058,12 @@ rack_clone_rsm(struct tcp_rack *rack, struct rack_sendmap *nrsm,
 	if (nrsm->r_flags & RACK_HAS_SYN)
 		nrsm->r_flags &= ~RACK_HAS_SYN;
 	/* Now if we have a FIN flag we keep it on the right edge */
-	if (nrsm->r_flags & RACK_HAS_FIN)
-		nrsm->r_flags &= ~RACK_HAS_FIN;
+	if (rsm->r_flags & RACK_HAS_FIN)
+		rsm->r_flags &= ~RACK_HAS_FIN;
+	/* Push bit must go to the right edge as well */
+	if (rsm->r_flags & RACK_HAD_PUSH)
+		rsm->r_flags &= ~RACK_HAD_PUSH;
+	
 	/*
 	 * Now we need to find nrsm's new location in the mbuf chain
 	 * we basically calculate a new offset, which is soff +
diff --git a/sys/netinet/tcp_subr.c b/sys/netinet/tcp_subr.c
index b9da908d2a15..bb2c35c76fde 100644
--- a/sys/netinet/tcp_subr.c
+++ b/sys/netinet/tcp_subr.c
@@ -3373,6 +3373,15 @@ tcp_mtudisc(struct inpcb *inp, int mtuoffer)
 	tp->snd_recover = tp->snd_max;
 	if (tp->t_flags & TF_SACK_PERMIT)
 		EXIT_FASTRECOVERY(tp->t_flags);
+	if (tp->t_fb->tfb_tcp_mtu_chg != NULL) {
+		/*
+		 * Conceptually the snd_nxt setting
+		 * and freeing sack holes should
+		 * be done by the default stacks
+		 * own tfb_tcp_mtu_chg().
+		 */
+		tp->t_fb->tfb_tcp_mtu_chg(tp);
+	}
 	tp->t_fb->tfb_tcp_output(tp);
 }