From e5cccc35c38e889545fad60588c64c9ab8daea67 Mon Sep 17 00:00:00 2001
From: Michael Tuexen <tuexen@FreeBSD.org>
Date: Tue, 12 Sep 2017 13:34:43 +0000
Subject: [PATCH] Add support to print the TCP stack being used.

Sponsored by:	Netflix, Inc.
---
 sys/netinet/tcp_var.h       |  2 +-
 usr.bin/sockstat/sockstat.1 | 15 +++++++--
 usr.bin/sockstat/sockstat.c | 61 ++++++++++++++++++++++++++-----------
 3 files changed, 57 insertions(+), 21 deletions(-)

diff --git a/sys/netinet/tcp_var.h b/sys/netinet/tcp_var.h
index 48305788d097..967a51398630 100644
--- a/sys/netinet/tcp_var.h
+++ b/sys/netinet/tcp_var.h
@@ -655,7 +655,7 @@ struct tcp_hhook_data {
 struct xtcpcb {
 	size_t		xt_len;		/* length of this structure */
 	struct xinpcb	xt_inp;
-	char		xt_stack[TCP_FUNCTION_NAME_LEN_MAX];	/* (n) */
+	char		xt_stack[TCP_FUNCTION_NAME_LEN_MAX];	/* (s) */
 	int64_t		spare64[8];
 	int32_t		t_state;		/* (s,p) */
 	uint32_t	t_flags;		/* (s,p) */
diff --git a/usr.bin/sockstat/sockstat.1 b/usr.bin/sockstat/sockstat.1
index 95247e4f8efa..3117eba4e038 100644
--- a/usr.bin/sockstat/sockstat.1
+++ b/usr.bin/sockstat/sockstat.1
@@ -27,7 +27,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd August 27, 2015
+.Dd September 12, 2017
 .Dt SOCKSTAT 1
 .Os
 .Sh NAME
@@ -35,7 +35,7 @@
 .Nd list open sockets
 .Sh SYNOPSIS
 .Nm
-.Op Fl 46cLlsu
+.Op Fl 46cLlSsu
 .Op Fl j Ar jid
 .Op Fl p Ar ports
 .Op Fl P Ar protocols
@@ -83,6 +83,9 @@ The
 argument is a comma-separated list of protocol names,
 as they are defined in
 .Xr protocols 5 .
+.It Fl S
+Display the protocol stack, if applicable.
+This is currently only implemented for TCP.
 .It Fl s
 Display the protocol state, if applicable.
 This is currently only implemented for SCTP and TCP.
@@ -143,6 +146,14 @@ if the endpoint could not be determined.
 (Internet sockets only)
 The address the foreign end of the socket is bound to (see
 .Xr getpeername 2 ) .
+.It Li STATE
+The protocol state if
+.Fl s
+is specified (only for SCTP or TCP).
+.It Li STACK
+The protocol stack if
+.Fl S
+is specified (only for TCP).
 .El
 .Pp
 If a socket is associated with more than one file descriptor,
diff --git a/usr.bin/sockstat/sockstat.c b/usr.bin/sockstat/sockstat.c
index 6235f8285793..71d21cc467ee 100644
--- a/usr.bin/sockstat/sockstat.c
+++ b/usr.bin/sockstat/sockstat.c
@@ -73,6 +73,7 @@ static int	 opt_c;		/* Show connected sockets */
 static int	 opt_j;		/* Show specified jail */
 static int	 opt_L;		/* Don't show IPv4 or IPv6 loopback sockets */
 static int	 opt_l;		/* Show listening sockets */
+static int	 opt_S;		/* Show protocol stack if applicable */
 static int	 opt_s;		/* Show protocol state if applicable */
 static int	 opt_u;		/* Show Unix domain sockets */
 static int	 opt_v;		/* Verbose mode */
@@ -106,6 +107,7 @@ struct sock {
 	int proto;
 	int state;
 	const char *protoname;
+	char stack[TCP_FUNCTION_NAME_LEN_MAX];
 	struct addr *laddr;
 	struct addr *faddr;
 	struct sock *next;
@@ -698,8 +700,11 @@ gather_inet(int proto)
 		sock->laddr = laddr;
 		sock->faddr = faddr;
 		sock->vflag = xip->inp_vflag;
-		if (proto == IPPROTO_TCP)
+		if (proto == IPPROTO_TCP) {
 			sock->state = xtp->t_state;
+			memcpy(sock->stack, xtp->xt_stack,
+			    TCP_FUNCTION_NAME_LEN_MAX);
+		}
 		sock->protoname = protoname;
 		hash = (int)((uintptr_t)sock->socket % HASHSIZE);
 		sock->next = sockhash[hash];
@@ -1040,21 +1045,36 @@ displaysock(struct sock *s, int pos)
 		default:
 			abort();
 		}
-		if (first && opt_s &&
-		    (s->proto == IPPROTO_SCTP || s->proto == IPPROTO_TCP)) {
-			while (pos < 80)
-				pos += xprintf(" ");
-			switch (s->proto) {
-			case IPPROTO_SCTP:
-				pos += xprintf("%s", sctp_state(s->state));
-				break;
-			case IPPROTO_TCP:
-				if (s->state >= 0 && s->state < TCP_NSTATES)
-					pos +=
-					    xprintf("%s", tcpstates[s->state]);
-				else
-					pos += xprintf("?");
-				break;
+		if (first) {
+			if (opt_s &&
+			    (s->proto == IPPROTO_SCTP ||
+			     s->proto == IPPROTO_TCP)) {
+				while (pos < 80)
+					pos += xprintf(" ");
+				switch (s->proto) {
+				case IPPROTO_SCTP:
+					pos += xprintf("%s",
+					    sctp_state(s->state));
+					break;
+				case IPPROTO_TCP:
+					if (s->state >= 0 &&
+					    s->state < TCP_NSTATES)
+						pos +=
+						    xprintf("%s",
+						        tcpstates[s->state]);
+					else
+						pos += xprintf("?");
+					break;
+				}
+			}
+			if (opt_S && s->proto == IPPROTO_TCP) {
+				while (pos < 80)
+					pos += xprintf(" ");
+				if (opt_s)
+					while (pos < 93)
+						pos += xprintf(" ");
+				xprintf("%.*s", TCP_FUNCTION_NAME_LEN_MAX,
+				    s->stack);
 			}
 		}
 		if (laddr != NULL)
@@ -1083,6 +1103,8 @@ display(void)
 	    "LOCAL ADDRESS", "FOREIGN ADDRESS");
 	if (opt_s)
 		printf(" %-12s", "STATE");
+	if (opt_S)
+		printf(" %.*s", TCP_FUNCTION_NAME_LEN_MAX, "STACK");
 	printf("\n");
 	setpassent(1);
 	for (xf = xfiles, n = 0; n < nxfiles; ++n, ++xf) {
@@ -1153,7 +1175,7 @@ static void
 usage(void)
 {
 	fprintf(stderr,
-	    "usage: sockstat [-46cLlsu] [-j jid] [-p ports] [-P protocols]\n");
+	    "usage: sockstat [-46cLlSsu] [-j jid] [-p ports] [-P protocols]\n");
 	exit(1);
 }
 
@@ -1164,7 +1186,7 @@ main(int argc, char *argv[])
 	int o, i;
 
 	opt_j = -1;
-	while ((o = getopt(argc, argv, "46cj:Llp:P:suv")) != -1)
+	while ((o = getopt(argc, argv, "46cj:Llp:P:Ssuv")) != -1)
 		switch (o) {
 		case '4':
 			opt_4 = 1;
@@ -1190,6 +1212,9 @@ main(int argc, char *argv[])
 		case 'P':
 			protos_defined = parse_protos(optarg);
 			break;
+		case 'S':
+			opt_S = 1;
+			break;
 		case 's':
 			opt_s = 1;
 			break;