git: 6873fec25b54 - stable/15 - tcp: minor cleanup

The branch stable/15 has been updated by tuexen:

URL: https://cgit.FreeBSD.org/src/commit/?id=6873fec25b542c1780bf1723e253856631b4b896

commit 6873fec25b542c1780bf1723e253856631b4b896
Author:     Michael Tuexen <tuexen@FreeBSD.org>
AuthorDate: 2026-08-24 19:00:14 +0000
Commit:     Michael Tuexen <tuexen@FreeBSD.org>
CommitDate: 2026-10-23 17:15:56 +0000

    tcp: minor cleanup
    
    Several cleanups in tcp_input_with_port():
    * Don't assign m twice.
    * Don't reassign pointers without having done pullup().
    * While there, change the type of isipv6 to bool, since it is used
      that way.
    No functional change intended.
    
    Reported by:            Hannes Elfert
    Reviewed by:            pouria, Timo Völker, Nick Banks
    Differential Revision:  https://reviews.freebsd.org/D59142
    
    (cherry picked from commit 191dad334c646457c012d0d0963505a2f2d73a98)
---
 sys/netinet/tcp_input.c | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/sys/netinet/tcp_input.c b/sys/netinet/tcp_input.c
index 15035cc913ab..a1786952741e 100644
--- a/sys/netinet/tcp_input.c
+++ b/sys/netinet/tcp_input.c
@@ -593,7 +593,7 @@ tcp6_input(struct mbuf **mp, int *offp, int proto)
 int
 tcp_input_with_port(struct mbuf **mp, int *offp, int proto, uint16_t port)
 {
-	struct mbuf *m = *mp;
+	struct mbuf *m;
 	struct tcphdr *th = NULL;
 	struct ip *ip = NULL;
 	struct inpcb *inp = NULL;
@@ -614,7 +614,7 @@ tcp_input_with_port(struct mbuf **mp, int *offp, int proto, uint16_t port)
 	struct m_tag *fwd_tag = NULL;
 #ifdef INET6
 	struct ip6_hdr *ip6 = NULL;
-	int isipv6;
+	bool isipv6;
 #else
 	const void *ip6 = NULL;
 #endif /* INET6 */
@@ -624,10 +624,6 @@ tcp_input_with_port(struct mbuf **mp, int *offp, int proto, uint16_t port)
 
 	NET_EPOCH_ASSERT();
 
-#ifdef INET6
-	isipv6 = (mtod(m, struct ip *)->ip_v == 6) ? 1 : 0;
-#endif
-
 	off0 = *offp;
 	m = *mp;
 	*mp = NULL;
@@ -636,6 +632,7 @@ tcp_input_with_port(struct mbuf **mp, int *offp, int proto, uint16_t port)
 
 	m->m_pkthdr.tcp_tun_port = port;
 #ifdef INET6
+	isipv6 = mtod(m, struct ip *)->ip_v == 6;
 	if (isipv6) {
 		ip6 = mtod(m, struct ip6_hdr *);
 		th = (struct tcphdr *)((caddr_t)ip6 + off0);
@@ -774,9 +771,9 @@ tcp_input_with_port(struct mbuf **mp, int *offp, int proto, uint16_t port)
 					TCPSTAT_INC(tcps_rcvshort);
 					return (IPPROTO_DONE);
 				}
+				ip6 = mtod(m, struct ip6_hdr *);
+				th = (struct tcphdr *)((caddr_t)ip6 + off0);
 			}
-			ip6 = mtod(m, struct ip6_hdr *);
-			th = (struct tcphdr *)((caddr_t)ip6 + off0);
 		}
 #endif
 #if defined(INET) && defined(INET6)