--- netinet/tcp_output.c	2008-04-23 01:27:11.000000000 +0200
+++ /u/perforce/tcp_reass/netinet/tcp_output.c	2008-05-08 00:37:13.000000000 +0200
@@ -49,6 +49,7 @@ __FBSDID("$FreeBSD: src/sys/netinet/tcp_
 #include <sys/socket.h>
 #include <sys/socketvar.h>
 #include <sys/sysctl.h>
+#include <sys/syslog.h>
 
 #include <net/route.h>
 
@@ -131,7 +132,7 @@ tcp_output(struct tcpcb *tp)
 	struct mbuf *m;
 	struct ip *ip = NULL;
 	struct ipovly *ipov = NULL;
-	struct tcphdr *th;
+	struct tcphdr *th = NULL;
 	u_char opt[TCP_MAXOLEN];
 	unsigned ipoptlen, optlen, hdrlen;
 #ifdef IPSEC
@@ -142,6 +143,8 @@ tcp_output(struct tcpcb *tp)
 	struct sackhole *p;
 	int tso = 0;
 	struct tcpopt to;
+	char *s;
+	int ipout = 0;
 #if 0
 	int maxburst = TCP_MAXBURST;
 #endif
 #ifdef TCP_SIGNATURE
@@ -1132,6 +1134,8 @@ timer:
 	if (path_mtu_discovery)
 		ip->ip_off |= IP_DF;
 
+	ipout = 1;
+
 	error = ip_output(m, tp->t_inpcb->inp_options, NULL,
 	    ((so->so_options & SO_DONTROUTE) ? IP_ROUTETOIF : 0), 0,
 	    tp->t_inpcb);
@@ -1165,6 +1169,13 @@ timer:
 		}
 out:
 		SOCKBUF_UNLOCK_ASSERT(&so->so_snd);	/* Check gotos. */
+
+		if ((s = tcp_log_addrs(&tp->t_inpcb->inp_inc, NULL, NULL, NULL))) {
+			log(LOG_DEBUG, "%s; %s: error %i while sending (ip_output %i)\n",
+			    s, __func__, error, ipout);
+			free(s, M_TCPLOG);
+		}
+
 		switch (error) {
 		case EPERM:
 			tp->t_softerror = error;