git: 5b1ebb6ef6b1 - stable/13 - tcp: add some debug output

The branch stable/13 has been updated by tuexen:

URL: https://cgit.FreeBSD.org/src/commit/?id=5b1ebb6ef6b187f3b7a9de58164d69ff2e09e2b8

commit 5b1ebb6ef6b187f3b7a9de58164d69ff2e09e2b8
Author:     Michael Tuexen <tuexen@FreeBSD.org>
AuthorDate: 2024-04-07 20:41:24 +0000
Commit:     Michael Tuexen <tuexen@FreeBSD.org>
CommitDate: 2024-08-01 20:41:21 +0000

    tcp: add some debug output
    
    Also log, when dropping text or FIN after having received a FIN.
    This is the intended behavior described in RFC 9293.
    A follow-up patch will enforce this behavior for the base stack
    and the RACK stack.
    
    Reviewed by:            rscheff
    Sponsored by:           Netflix, Inc.
    Differential Revision:  https://reviews.freebsd.org/D44669
    
    (cherry picked from commit e8c149ab85c7834f76325864f22ca89298e65f75)
---
 sys/netinet/tcp_input.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/sys/netinet/tcp_input.c b/sys/netinet/tcp_input.c
index af6afbd271bb..df4205ef84e1 100644
--- a/sys/netinet/tcp_input.c
+++ b/sys/netinet/tcp_input.c
@@ -3298,6 +3298,35 @@ dodata:							/* XXX */
 			len = so->so_rcv.sb_hiwat;
 #endif
 	} else {
+		if ((s = tcp_log_addrs(inc, th, NULL, NULL))) {
+			if (tlen > 0) {
+				if ((thflags & TH_FIN) != 0) {
+					log(LOG_DEBUG, "%s; %s: %s: "
+					    "Received %d bytes of data and FIN "
+					    "after having received a FIN, "
+					    "just dropping both\n",
+					    s, __func__,
+					    tcpstates[tp->t_state], tlen);
+				} else {
+					log(LOG_DEBUG, "%s; %s: %s: "
+					    "Received %d bytes of data "
+					    "after having received a FIN, "
+					    "just dropping it\n",
+					    s, __func__,
+					    tcpstates[tp->t_state], tlen);
+				}
+			} else {
+				if ((thflags & TH_FIN) != 0) {
+					log(LOG_DEBUG, "%s; %s: %s: "
+					    "Received FIN "
+					    "after having received a FIN, "
+					    "just dropping it\n",
+					    s, __func__,
+					    tcpstates[tp->t_state]);
+				}
+			}
+			free(s, M_TCPLOG);
+		}
 		m_freem(m);
 		thflags &= ~TH_FIN;
 	}