git: ea5560f2293b - stable/14 - tcp: increase tcps_sc_recvcookie only in the syncache_expand()

The branch stable/14 has been updated by tuexen:

URL: https://cgit.FreeBSD.org/src/commit/?id=ea5560f2293b9f2c69f62cba6b122c91b0b8eb3b

commit ea5560f2293b9f2c69f62cba6b122c91b0b8eb3b
Author:     Gleb Smirnoff <glebius@FreeBSD.org>
AuthorDate: 2025-06-17 15:50:17 +0000
Commit:     Michael Tuexen <tuexen@FreeBSD.org>
CommitDate: 2025-09-09 18:06:19 +0000

    tcp: increase tcps_sc_recvcookie only in the syncache_expand()
    
    The syncookie_expand() is called from syncookie_cmp() in INVARIANTS mode
    to confirm that values calculated via syncookies mechanism match those
    stored in the syncache entry.  This creates a counting bug, that with
    INVARIANTS every successful use of syncache also counts as use of a
    syncookie.
    
    Reviewed by:            tuexen
    Differential Revision:  https://reviews.freebsd.org/D50897
    
    (cherry picked from commit 3ed8d5645dd42a7c080ba800cf6d25cb7e147d7e)
---
 sys/netinet/tcp_syncache.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/sys/netinet/tcp_syncache.c b/sys/netinet/tcp_syncache.c
index c7da8a41242e..b50d6e9ea84e 100644
--- a/sys/netinet/tcp_syncache.c
+++ b/sys/netinet/tcp_syncache.c
@@ -1123,8 +1123,10 @@ syncache_expand(struct in_conninfo *inc, struct tcpopt *to, struct tcphdr *th,
 			goto failed;
 		}
 		bzero(&scs, sizeof(scs));
-		if (syncookie_expand(inc, sch, &scs, th, to, *lsop, port))
+		if (syncookie_expand(inc, sch, &scs, th, to, *lsop, port)) {
 			sc = &scs;
+			TCPSTAT_INC(tcps_sc_recvcookie);
+		}
 		if (locked)
 			SCH_UNLOCK(sch);
 		if (sc == NULL) {
@@ -2355,7 +2357,6 @@ syncookie_expand(struct in_conninfo *inc, const struct syncache_head *sch,
 
 	sc->sc_port = port;
 
-	TCPSTAT_INC(tcps_sc_recvcookie);
 	return (true);
 }