Add the ability to see TCP timers via netstat -x. This can be a useful

feature when you have a seemingly stuck socket and want to figure
out why it has not been closed yet.

No plans to MFC this, as it changes the netstat sysctl ABI.

Reviewed by:	andre, rwatson, Eric Van Gyzen

sys/netinet/tcp_subr.c

@@ -1151,8 +1151,11 @@ tcp_pcblist(SYSCTL_HANDLER_ARGS)
 			else if (inp->inp_flags & INP_TIMEWAIT) {
 				bzero((char *) &xt.xt_tp, sizeof xt.xt_tp);
 				xt.xt_tp.t_state = TCPS_TIME_WAIT;
-			} else
+			} else {
 				bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp);
+				if (xt.xt_tp.t_timers)
+					tcp_timer_to_xtimer(&xt.xt_tp, xt.xt_tp.t_timers, &xt.xt_timer);
+			}
 			if (inp->inp_socket != NULL)
 				sotoxsocket(inp->inp_socket, &xt.xt_socket);
 			else {

sys/netinet/tcp_timer.c

@@ -659,3 +659,24 @@ tcp_timer_active(struct tcpcb *tp, int timer_type)
 		}
 	return callout_active(t_callout);
 }
+
+#define	ticks_to_msecs(t)	(1000*(t) / hz)
+
+void
+tcp_timer_to_xtimer(struct tcpcb *tp, struct tcp_timer *timer, struct xtcp_timer *xtimer)
+{
+	bzero(xtimer, sizeof(struct xtcp_timer));
+	if (timer == NULL)
+		return;
+	if (callout_active(&timer->tt_delack))
+		xtimer->tt_delack = ticks_to_msecs(timer->tt_delack.c_time - ticks);
+	if (callout_active(&timer->tt_rexmt))
+		xtimer->tt_rexmt = ticks_to_msecs(timer->tt_rexmt.c_time - ticks);
+	if (callout_active(&timer->tt_persist))
+		xtimer->tt_persist = ticks_to_msecs(timer->tt_persist.c_time - ticks);
+	if (callout_active(&timer->tt_keep))
+		xtimer->tt_keep = ticks_to_msecs(timer->tt_keep.c_time - ticks);
+	if (callout_active(&timer->tt_2msl))
+		xtimer->tt_2msl = ticks_to_msecs(timer->tt_2msl.c_time - ticks);
+	xtimer->t_rcvtime = ticks_to_msecs(ticks - tp->t_rcvtime);
+}

sys/netinet/tcp_timer.h

@@ -141,6 +141,8 @@ static const char *tcptimers[] =
 
 #ifdef _KERNEL
 
+struct xtcp_timer;
+
 struct tcp_timer {
 	struct	callout tt_rexmt;	/* retransmit timer */
 	struct	callout tt_persist;	/* retransmit persistence */
@@ -177,6 +179,8 @@ void	tcp_timer_keep(void *xtp);
 void	tcp_timer_persist(void *xtp);
 void	tcp_timer_rexmt(void *xtp);
 void	tcp_timer_delack(void *xtp);
+void	tcp_timer_to_xtimer(struct tcpcb *tp, struct tcp_timer *timer,
+	struct xtcp_timer *xtimer);
 
 #endif /* _KERNEL */
 

sys/netinet/tcp_var.h

@@ -495,11 +495,20 @@ void	kmod_tcpstat_inc(int statnum);
  * included.  Not all of our clients do.
  */
 #if defined(_NETINET_IN_PCB_H_) && defined(_SYS_SOCKETVAR_H_)
+struct xtcp_timer {
+	int tt_rexmt;	/* retransmit timer */
+	int tt_persist;	/* retransmit persistence */
+	int tt_keep;	/* keepalive */
+	int tt_2msl;	/* 2*msl TIME_WAIT timer */
+	int tt_delack;	/* delayed ACK timer */
+	int t_rcvtime; 	/* Time since last packet received */
+};
 struct	xtcpcb {
 	size_t	xt_len;
 	struct	inpcb	xt_inp;
 	struct	tcpcb	xt_tp;
 	struct	xsocket	xt_socket;
+	struct	xtcp_timer xt_timer;
 	u_quad_t	xt_alignment_hack;
 };
 #endif

usr.bin/netstat/inet.c

@@ -313,6 +313,7 @@ protopr(u_long off, const char *name, int af1, int proto)
 	struct inpcb *inp;
 	struct xinpgen *xig, *oxig;
 	struct xsocket *so;
+	struct xtcp_timer *timer;
 
 	istcp = 0;
 	switch (proto) {
@@ -347,6 +348,7 @@ protopr(u_long off, const char *name, int af1, int proto)
 	     xig->xig_len > sizeof(struct xinpgen);
 	     xig = (struct xinpgen *)((char *)xig + xig->xig_len)) {
 		if (istcp) {
+			timer = &((struct xtcpcb *)xig)->xt_timer;
 			tp = &((struct xtcpcb *)xig)->xt_tp;
 			inp = &((struct xtcpcb *)xig)->xt_inp;
 			so = &((struct xtcpcb *)xig)->xt_socket;
@@ -414,14 +416,17 @@ protopr(u_long off, const char *name, int af1, int proto)
 				       "%-5.5s %-6.6s %-6.6s  %-22.22s %-22.22s",
 				       "Proto", "Recv-Q", "Send-Q",
 				       "Local Address", "Foreign Address");
-				if (xflag)
-					printf("%-6.6s %-6.6s %-6.6s %-6.6s %-6.6s %-6.6s %-6.6s %-6.6s %-6.6s %-6.6s %-6.6s %-6.6s %s\n",
+				if (xflag) {
+					printf("%-6.6s %-6.6s %-6.6s %-6.6s %-6.6s %-6.6s %-6.6s %-6.6s %-6.6s %-6.6s %-6.6s %-6.6s ",
 					       	"R-MBUF", "S-MBUF", "R-CLUS", 
 						"S-CLUS", "R-HIWA", "S-HIWA", 
 						"R-LOWA", "S-LOWA", "R-BCNT", 
-						"S-BCNT", "R-BMAX", "S-BMAX",
-					       "(state)");
-				else
+						"S-BCNT", "R-BMAX", "S-BMAX");
+					printf("%7.7s %7.7s %7.7s %7.7s %7.7s %7.7s %s\n",
+						"rexmt", "persist", "keep",
+						"2msl", "delack", "rcvtime",
+                                               "(state)");
+				} else
 					printf("(state)\n");
 			}
 			first = 0;
@@ -516,7 +521,7 @@ protopr(u_long off, const char *name, int af1, int proto)
 				       so->so_rcv.sb_lowat, so->so_snd.sb_lowat,
 				       so->so_rcv.sb_mbcnt, so->so_snd.sb_mbcnt,
 				       so->so_rcv.sb_mbmax, so->so_snd.sb_mbmax);
-			else
+			else {
 				printf("%6u %6u %6u %6u %6u %6u %6u %6u %6u %6u %6u %6u ",
 				       so->so_rcv.sb_mcnt, so->so_snd.sb_mcnt,
 				       so->so_rcv.sb_ccnt, so->so_snd.sb_ccnt,
@@ -524,6 +529,14 @@ protopr(u_long off, const char *name, int af1, int proto)
 				       so->so_rcv.sb_lowat, so->so_snd.sb_lowat,
 				       so->so_rcv.sb_mbcnt, so->so_snd.sb_mbcnt,
 				       so->so_rcv.sb_mbmax, so->so_snd.sb_mbmax);
+				printf("%4d.%02d %4d.%02d %4d.%02d %4d.%02d %4d.%02d %4d.%02d ",
+					timer->tt_rexmt / 1000, (timer->tt_rexmt % 1000) / 10,
+					timer->tt_persist / 1000, (timer->tt_persist % 1000) / 10,
+					timer->tt_keep / 1000, (timer->tt_keep % 1000) / 10,
+					timer->tt_2msl / 1000, (timer->tt_2msl % 1000) / 10,
+					timer->tt_delack / 1000, (timer->tt_delack % 1000) / 10,
+					timer->t_rcvtime / 1000, (timer->t_rcvtime % 1000) / 10);
+			}
 		}
 		if (istcp && !Lflag) {
 			if (tp->t_state < 0 || tp->t_state >= TCP_NSTATES)

usr.bin/netstat/netstat.1

@@ -87,7 +87,7 @@ show network addresses as numbers (as with
 but show ports symbolically.
 If
 .Fl x
-is present display full socket buffer statistics for each internet socket.
+is present, display socket buffer and tcp timer statistics for each internet socket.
 .It Xo
 .Bk -words
 .Nm