Add support for multiple listening sockets

One can now specify multiple "listen on" statements. The default is to
listen on 0.0.0.0 and ::, which means better handling of dual-stack
setups.  ok sthen@ on a previous version, input and ok reyk@.

5 files changed, 87 insertions, 51 deletions

diff --git a/usr.sbin/snmpd/control.c b/usr.sbin/snmpd/control.c
index c4240d14f3b..833d2be7725 100644
--- a/usr.sbin/snmpd/control.c
+++ b/usr.sbin/snmpd/control.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: control.c,v 1.39 2016/09/02 13:28:36 eric Exp $	*/
+/*	$OpenBSD: control.c,v 1.40 2016/11/18 16:16:39 jca Exp $	*/
 
 /*
  * Copyright (c) 2010-2013 Reyk Floeter <reyk@openbsd.org>
@@ -592,7 +592,7 @@ control_dispatch_agentx(int fd, short event, void *arg)
 				}
 			}
  dispatch:
-			snmpe_dispatchmsg(msg);
+			snmpe_dispatchmsg(msg, fd);
 			break;
 		}
 
diff --git a/usr.sbin/snmpd/parse.y b/usr.sbin/snmpd/parse.y
index f173650fcab..533db0b2ab7 100644
--- a/usr.sbin/snmpd/parse.y
+++ b/usr.sbin/snmpd/parse.y
@@ -1,4 +1,4 @@
-/*	$OpenBSD: parse.y,v 1.40 2016/11/09 20:31:56 jca Exp $	*/
+/*	$OpenBSD: parse.y,v 1.41 2016/11/18 16:16:39 jca Exp $	*/
 
 /*
  * Copyright (c) 2007, 2008, 2012 Reyk Floeter <reyk@openbsd.org>
@@ -198,25 +198,13 @@ yesno		:  STRING			{
 		;
 
 main		: LISTEN ON STRING		{
-			struct addresslist	 al;
-			struct address		*h;
-
-			TAILQ_INIT(&al);
-			if (host($3, &al, 1, SNMPD_PORT, NULL, NULL, NULL)
-			    <= 0) {
+			if (host($3, &conf->sc_addresses, 16, SNMPD_PORT, NULL,
+			    NULL, NULL) <= 0) {
 				yyerror("invalid ip address: %s", $3);
 				free($3);
 				YYERROR;
 			}
 			free($3);
-			h = TAILQ_FIRST(&al);
-			bcopy(&h->ss, &conf->sc_address.ss, sizeof(*h));
-			conf->sc_address.port = h->port;
-
-			while ((h = TAILQ_FIRST(&al)) != NULL) {
-				TAILQ_REMOVE(&al, h, entry);
-				free(h);
-			}
 		}
 		| READONLY COMMUNITY STRING	{
 			if (strlcpy(conf->sc_rdcommunity, $3,
@@ -989,8 +977,8 @@ parse_config(const char *filename, u_int flags)
 
 	conf->sc_flags = flags;
 	conf->sc_confpath = filename;
-	conf->sc_address.ss.ss_family = AF_INET;
-	conf->sc_address.port = SNMPD_PORT;
+	TAILQ_INIT(&conf->sc_addresses);
+	TAILQ_INIT(&conf->sc_sockets);
 	conf->sc_ps.ps_csock.cs_name = SNMPD_SOCKET;
 	TAILQ_INIT(&conf->sc_ps.ps_rcsocks);
 	strlcpy(conf->sc_rdcommunity, "public", SNMPD_MAXCOMMUNITYLEN);
@@ -1011,6 +999,20 @@ parse_config(const char *filename, u_int flags)
 
 	endservent();
 
+	if (TAILQ_EMPTY(&conf->sc_addresses)) {
+		struct address		*h;
+		if ((h = calloc(1, sizeof(*h))) == NULL)
+			fatal("snmpe: %s", __func__);
+		h->ss.ss_family = AF_INET;
+		h->port = SNMPD_PORT;
+		TAILQ_INSERT_TAIL(&conf->sc_addresses, h, entry);
+		if ((h = calloc(1, sizeof(*h))) == NULL)
+			fatal("snmpe: %s", __func__);
+		h->ss.ss_family = AF_INET6;
+		h->port = SNMPD_PORT;
+		TAILQ_INSERT_TAIL(&conf->sc_addresses, h, entry);
+	}
+
 	/* Free macros and check which have not been used. */
 	for (sym = TAILQ_FIRST(&symhead); sym != NULL; sym = next) {
 		next = TAILQ_NEXT(sym, entry);
@@ -1215,7 +1217,7 @@ host_dns(const char *s, struct addresslist *al, int max,
 
 		h->sa_srcaddr = src;
 
-		TAILQ_INSERT_HEAD(al, h, entry);
+		TAILQ_INSERT_TAIL(al, h, entry);
 		cnt++;
 	}
 	if (cnt == max && res) {
@@ -1262,7 +1264,7 @@ host(const char *s, struct addresslist *al, int max,
 		}
 		h->sa_srcaddr = src;
 
-		TAILQ_INSERT_HEAD(al, h, entry);
+		TAILQ_INSERT_TAIL(al, h, entry);
 		return (1);
 	}
 
diff --git a/usr.sbin/snmpd/snmpd.h b/usr.sbin/snmpd/snmpd.h
index 38d01f0f5bd..46782c3f46d 100644
--- a/usr.sbin/snmpd/snmpd.h
+++ b/usr.sbin/snmpd/snmpd.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: snmpd.h,v 1.72 2016/11/09 20:31:56 jca Exp $	*/
+/*	$OpenBSD: snmpd.h,v 1.73 2016/11/18 16:16:39 jca Exp $	*/
 
 /*
  * Copyright (c) 2007, 2008, 2012 Reyk Floeter <reyk@openbsd.org>
@@ -518,6 +518,13 @@ struct address {
 };
 TAILQ_HEAD(addresslist, address);
 
+struct listen_sock {
+	int				s_fd;
+	struct event			s_ev;
+	TAILQ_ENTRY(listen_sock)	entry;
+};
+TAILQ_HEAD(socklist, listen_sock);
+
 enum usmauth {
 	AUTH_NONE = 0,
 	AUTH_MD5,	/* HMAC-MD5-96, RFC3414 */
@@ -556,9 +563,8 @@ struct snmpd {
 #define SNMPD_F_NONAMES		 0x02
 
 	const char		*sc_confpath;
-	struct address		 sc_address;
-	int			 sc_sock;
-	struct event		 sc_ev;
+	struct addresslist	 sc_addresses;
+	struct socklist		 sc_sockets;
 	struct timeval		 sc_starttime;
 	u_int32_t		 sc_engine_boots;
 
@@ -652,7 +658,7 @@ struct kif_arp	*karp_getaddr(struct sockaddr *, u_short, int);
 /* snmpe.c */
 void		 snmpe(struct privsep *, struct privsep_proc *);
 void		 snmpe_shutdown(void);
-void		 snmpe_dispatchmsg(struct snmp_message *);
+void		 snmpe_dispatchmsg(struct snmp_message *, int);
 
 /* trap.c */
 void		 trap_init(void);
diff --git a/usr.sbin/snmpd/snmpe.c b/usr.sbin/snmpd/snmpe.c
index 23d0dfe32c5..7bb2ea6ee32 100644
--- a/usr.sbin/snmpd/snmpe.c
+++ b/usr.sbin/snmpd/snmpe.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: snmpe.c,v 1.45 2016/11/09 20:31:56 jca Exp $	*/
+/*	$OpenBSD: snmpe.c,v 1.46 2016/11/18 16:16:39 jca Exp $	*/
 
 /*
  * Copyright (c) 2007, 2008, 2012 Reyk Floeter <reyk@openbsd.org>
@@ -61,7 +61,9 @@ static struct privsep_proc procs[] = {
 void
 snmpe(struct privsep *ps, struct privsep_proc *p)
 {
-	struct snmpd	*env = ps->ps_env;
+	struct snmpd		*env = ps->ps_env;
+	struct address		*h;
+	struct listen_sock	*so;
 #ifdef DEBUG
 	char		 buf[BUFSIZ];
 	struct oid	*oid;
@@ -74,9 +76,13 @@ snmpe(struct privsep *ps, struct privsep_proc *p)
 	}
 #endif
 
-	/* bind SNMP UDP socket */
-	if ((env->sc_sock = snmpe_bind(&env->sc_address)) == -1)
-		fatalx("snmpe: failed to bind SNMP UDP socket");
+	TAILQ_FOREACH(h, &env->sc_addresses, entry) {
+		if ((so = calloc(1, sizeof(*so))) == NULL)
+			fatal("snmpe: %s", __func__);
+		if ((so->s_fd = snmpe_bind(h)) == -1)
+			fatal("snmpe: failed to bind SNMP UDP socket");
+		TAILQ_INSERT_TAIL(&env->sc_sockets, so, entry);
+	}
 
 	proc_run(ps, p, procs, nitems(procs), snmpe_init, NULL);
 }
@@ -85,7 +91,8 @@ snmpe(struct privsep *ps, struct privsep_proc *p)
 void
 snmpe_init(struct privsep *ps, struct privsep_proc *p, void *arg)
 {
-	struct snmpd	*env = ps->ps_env;
+	struct snmpd		*env = ps->ps_env;
+	struct listen_sock	*so;
 
 	kr_init();
 	trap_init();
@@ -93,9 +100,11 @@ snmpe_init(struct privsep *ps, struct privsep_proc *p, void *arg)
 	usm_generate_keys();
 
 	/* listen for incoming SNMP UDP messages */
-	event_set(&env->sc_ev, env->sc_sock, EV_READ|EV_PERSIST,
-	    snmpe_recvmsg, env);
-	event_add(&env->sc_ev, NULL);
+	TAILQ_FOREACH(so, &env->sc_sockets, entry) {
+		event_set(&so->s_ev, so->s_fd, EV_READ|EV_PERSIST,
+		    snmpe_recvmsg, env);
+		event_add(&so->s_ev, NULL);
+	}
 }
 
 void
@@ -156,7 +165,7 @@ snmpe_bind(struct address *addr)
 	if (print_host(&addr->ss, buf, sizeof(buf)) == NULL)
 		goto bad;
 
-	log_info("snmpe_bind: binding to address %s:%d", buf, addr->port);
+	log_info("snmpe: listening on %s:%d", buf, addr->port);
 
 	return (s);
 
@@ -519,18 +528,18 @@ snmpe_recvmsg(int fd, short sig, void *arg)
 		}
 	}
 
-	snmpe_dispatchmsg(msg);
+	snmpe_dispatchmsg(msg, fd);
 }
 
 void
-snmpe_dispatchmsg(struct snmp_message *msg)
+snmpe_dispatchmsg(struct snmp_message *msg, int sock)
 {
 	if (snmpe_parsevarbinds(msg) == 1)
 		return;
 
 	/* not dispatched to subagent; respond directly */
 	msg->sm_context = SNMP_C_GETRESP;
-	snmpe_response(snmpd_env->sc_sock, msg);
+	snmpe_response(sock, msg);
 }
 
 void
diff --git a/usr.sbin/snmpd/traphandler.c b/usr.sbin/snmpd/traphandler.c
index a89ac42c120..76f48bfa031 100644
--- a/usr.sbin/snmpd/traphandler.c
+++ b/usr.sbin/snmpd/traphandler.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: traphandler.c,v 1.6 2016/10/28 09:07:08 rzalamena Exp $	*/
+/*	$OpenBSD: traphandler.c,v 1.7 2016/11/18 16:16:39 jca Exp $	*/
 
 /*
  * Copyright (c) 2014 Bret Stephen Lambert <blambert@openbsd.org>
@@ -43,8 +43,6 @@
 #include "snmpd.h"
 #include "mib.h"
 
-int	 trapsock;
-struct event trapev;
 char	 trap_path[PATH_MAX];
 
 void	 traphandler_init(struct privsep *, struct privsep_proc *, void *arg);
@@ -76,10 +74,18 @@ void
 traphandler(struct privsep *ps, struct privsep_proc *p)
 {
 	struct snmpd		*env = ps->ps_env;
-
-	if (env->sc_traphandler &&
-	    (trapsock = traphandler_bind(&env->sc_address)) == -1)
-		fatal("could not create trap listener socket");
+	struct address		*h;
+	struct listen_sock	*so;
+
+	if (env->sc_traphandler) {
+		TAILQ_FOREACH(h, &env->sc_addresses, entry) {
+			if ((so = calloc(1, sizeof(*so))) == NULL)
+				fatal("%s", __func__);
+			if ((so->s_fd = traphandler_bind(h)) == -1)
+				fatal("could not create trap listener socket");
+			TAILQ_INSERT_TAIL(&env->sc_sockets, so, entry);
+		}
+	}
 
 	proc_run(ps, p, procs, nitems(procs), traphandler_init, NULL);
 }
@@ -88,20 +94,24 @@ void
 traphandler_init(struct privsep *ps, struct privsep_proc *p, void *arg)
 {
 	struct snmpd		*env = ps->ps_env;
+	struct listen_sock	*so;
 
 	if (!env->sc_traphandler)
 		return;
 
 	/* listen for SNMP trap messages */
-	event_set(&trapev, trapsock, EV_READ|EV_PERSIST, traphandler_recvmsg,
-	    ps);
-	event_add(&trapev, NULL);
+	TAILQ_FOREACH(so, &env->sc_sockets, entry) {
+		event_set(&so->s_ev, so->s_fd, EV_READ|EV_PERSIST,
+		    traphandler_recvmsg, ps);
+		event_add(&so->s_ev, NULL);
+	}
 }
 
 int
 traphandler_bind(struct address *addr)
 {
 	int			 s;
+	char			 buf[512];
 
 	if ((s = snmpd_socket_af(&addr->ss, htons(SNMPD_TRAPPORT))) == -1)
 		return (-1);
@@ -112,6 +122,11 @@ traphandler_bind(struct address *addr)
 	if (bind(s, (struct sockaddr *)&addr->ss, addr->ss.ss_len) == -1)
 		goto bad;
 
+	if (print_host(&addr->ss, buf, sizeof(buf)) == NULL)
+		goto bad;
+
+	log_info("traphandler: listening on %s:%d", buf, SNMPD_TRAPPORT);
+
 	return (s);
  bad:
 	close (s);
@@ -121,8 +136,12 @@ traphandler_bind(struct address *addr)
 void
 traphandler_shutdown(void)
 {
-	event_del(&trapev);
-	close(trapsock);
+	struct listen_sock	*so;
+
+	TAILQ_FOREACH(so, &snmpd_env->sc_sockets, entry) {
+		event_del(&so->s_ev);
+		close(so->s_fd);
+	}
 }
 
 int