The syncache has made use of TCPDEBUG problematic, because the SYN

segments are lost for the application. This broke, for example,
ports/benchmarks/dbs which needs the SYN segment to filter the
contents of the trace buffer for the connection it is interested in.

This patch makes the SYN segments available again. Unfortunately they
are now associated with the listening socket instead of the new one, so
a change to applications is required, but without this patch it wouldn't
work altogether.

PR:		kern/45966

1 files changed, 41 insertions, 0 deletions

diff --git a/sys/netinet/tcp_syncache.c b/sys/netinet/tcp_syncache.c
index 239592e..1f00101 100644
--- a/sys/netinet/tcp_syncache.c
+++ b/sys/netinet/tcp_syncache.c
@@ -37,6 +37,7 @@
 #include "opt_inet6.h"
 #include "opt_ipsec.h"
 #include "opt_mac.h"
+#include "opt_tcpdebug.h"
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -68,10 +69,16 @@
 #include <netinet6/in6_pcb.h>
 #endif
 #include <netinet/tcp.h>
+#ifdef TCPDEBUG
+#include <netinet/tcpip.h>
+#endif
 #include <netinet/tcp_fsm.h>
 #include <netinet/tcp_seq.h>
 #include <netinet/tcp_timer.h>
 #include <netinet/tcp_var.h>
+#ifdef TCPDEBUG
+#include <netinet/tcp_debug.h>
+#endif
 #ifdef INET6
 #include <netinet6/tcp6_var.h>
 #endif
@@ -104,7 +111,11 @@ static void	 syncache_drop(struct syncache *, struct syncache_head *);
 static void	 syncache_free(struct syncache *);
 static void	 syncache_insert(struct syncache *, struct syncache_head *);
 struct syncache *syncache_lookup(struct in_conninfo *, struct syncache_head **);
+#ifdef TCPDEBUG
+static int	 syncache_respond(struct syncache *, struct mbuf *, struct socket *);
+#else
 static int	 syncache_respond(struct syncache *, struct mbuf *);
+#endif
 static struct 	 socket *syncache_socket(struct syncache *, struct socket *,
 		    struct mbuf *m);
 static void	 syncache_timer(void *);
@@ -397,7 +408,11 @@ syncache_timer(xslot)
 		 * to modify another entry, so do not obtain the next
 		 * entry on the timer chain until it has completed.
 		 */
+#ifdef TCPDEBUG
+		(void) syncache_respond(sc, NULL, NULL);
+#else
 		(void) syncache_respond(sc, NULL);
+#endif
 		nsc = TAILQ_NEXT(sc, sc_timerq);
 		tcpstat.tcps_sc_retransmitted++;
 		TAILQ_REMOVE(&tcp_syncache.timerq[slot], sc, sc_timerq);
@@ -870,7 +885,11 @@ syncache_add(inc, to, th, sop, m)
 		 */
 		sc->sc_tp = tp;
 		sc->sc_inp_gencnt = tp->t_inpcb->inp_gencnt;
+#ifdef TCPDEBUG
+		if (syncache_respond(sc, m, so) == 0) {
+#else
 		if (syncache_respond(sc, m) == 0) {
+#endif
 		        s = splnet();
 			TAILQ_REMOVE(&tcp_syncache.timerq[sc->sc_rxtslot],
 			    sc, sc_timerq);
@@ -1027,7 +1046,11 @@ syncache_add(inc, to, th, sop, m)
 	 * TAO test failed or there was no CC option,
 	 *    do a standard 3-way handshake.
 	 */
+#ifdef TCPDEBUG
+	if (syncache_respond(sc, m, so) == 0) {
+#else
 	if (syncache_respond(sc, m) == 0) {
+#endif
 		syncache_insert(sc, sch);
 		tcpstat.tcps_sndacks++;
 		tcpstat.tcps_sndtotal++;
@@ -1039,10 +1062,18 @@ syncache_add(inc, to, th, sop, m)
 	return (1);
 }
 
+#ifdef TCPDEBUG
+static int
+syncache_respond(sc, m, so)
+	struct syncache *sc;
+	struct mbuf *m;
+	struct socket *so;
+#else
 static int
 syncache_respond(sc, m)
 	struct syncache *sc;
 	struct mbuf *m;
+#endif
 {
 	u_int8_t *optp;
 	int optlen, error;
@@ -1217,6 +1248,16 @@ syncache_respond(sc, m)
 		    htons(tlen - hlen + IPPROTO_TCP));
 		m->m_pkthdr.csum_flags = CSUM_TCP;
 		m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
+#ifdef TCPDEBUG
+		/*
+		 * Trace.
+		 */
+		if (so != NULL && so->so_options & SO_DEBUG) {
+			struct tcpcb *tp = sototcpcb(so);
+			tcp_trace(TA_OUTPUT, tp->t_state, tp,
+			    mtod(m, void *), th, 0);
+		}
+#endif
 		error = ip_output(m, sc->sc_ipopts, &sc->sc_route, 0, NULL,
 				sc->sc_tp->t_inpcb);
 	}