Repair AgentX support.

which I broke when adding support for multiple listen address.  SNMP
data should be sent to the client using the appropriate socket, which we
now store when we receive the query.

Reported & fix tested by Rivo Nurges.

3 files changed, 14 insertions, 12 deletions

diff --git a/usr.sbin/snmpd/control.c b/usr.sbin/snmpd/control.c
index a4d04dc835e..d332bd1f82f 100644
--- a/usr.sbin/snmpd/control.c
+++ b/usr.sbin/snmpd/control.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: control.c,v 1.41 2017/01/09 14:49:22 reyk Exp $	*/
+/*	$OpenBSD: control.c,v 1.42 2017/04/21 13:50:23 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, fd);
+			snmpe_dispatchmsg(msg);
 			break;
 		}
 
diff --git a/usr.sbin/snmpd/snmpd.h b/usr.sbin/snmpd/snmpd.h
index 471f1f1bc44..91186f23e42 100644
--- a/usr.sbin/snmpd/snmpd.h
+++ b/usr.sbin/snmpd/snmpd.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: snmpd.h,v 1.74 2017/01/09 14:49:22 reyk Exp $	*/
+/*	$OpenBSD: snmpd.h,v 1.75 2017/04/21 13:50:23 jca Exp $	*/
 
 /*
  * Copyright (c) 2007, 2008, 2012 Reyk Floeter <reyk@openbsd.org>
@@ -401,6 +401,7 @@ struct pfr_buffer {
 #define MSG_REPORT(m)		(((m)->sm_flags & SNMP_MSGFLAG_REPORT) != 0)
 
 struct snmp_message {
+	int			 sm_sock;
 	struct sockaddr_storage	 sm_ss;
 	socklen_t		 sm_slen;
 	char			 sm_host[HOST_NAME_MAX+1];
@@ -660,7 +661,7 @@ 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 *, int);
+void		 snmpe_dispatchmsg(struct snmp_message *);
 
 /* trap.c */
 void		 trap_init(void);
diff --git a/usr.sbin/snmpd/snmpe.c b/usr.sbin/snmpd/snmpe.c
index 7bb2ea6ee32..ec50621a6eb 100644
--- a/usr.sbin/snmpd/snmpe.c
+++ b/usr.sbin/snmpd/snmpe.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: snmpe.c,v 1.46 2016/11/18 16:16:39 jca Exp $	*/
+/*	$OpenBSD: snmpe.c,v 1.47 2017/04/21 13:50:23 jca Exp $	*/
 
 /*
  * Copyright (c) 2007, 2008, 2012 Reyk Floeter <reyk@openbsd.org>
@@ -42,7 +42,7 @@
 void	 snmpe_init(struct privsep *, struct privsep_proc *, void *);
 int	 snmpe_parse(struct snmp_message *);
 int	 snmpe_parsevarbinds(struct snmp_message *);
-void	 snmpe_response(int, struct snmp_message *);
+void	 snmpe_response(struct snmp_message *);
 unsigned long
 	 snmpe_application(struct ber_element *);
 void	 snmpe_sig_handler(int sig, short, void *);
@@ -489,6 +489,7 @@ snmpe_recvmsg(int fd, short sig, void *arg)
 	if ((msg = calloc(1, sizeof(*msg))) == NULL)
 		return;
 
+	msg->sm_sock = fd;
 	msg->sm_slen = sizeof(msg->sm_ss);
 	if ((len = recvfromto(fd, msg->sm_data, sizeof(msg->sm_data), 0,
 	    (struct sockaddr *)&msg->sm_ss, &msg->sm_slen,
@@ -520,7 +521,7 @@ snmpe_recvmsg(int fd, short sig, void *arg)
 	if (snmpe_parse(msg) == -1) {
 		if (msg->sm_usmerr != 0 && MSG_REPORT(msg)) {
 			usm_make_report(msg);
-			snmpe_response(fd, msg);
+			snmpe_response(msg);
 			return;
 		} else {
 			snmp_msgfree(msg);
@@ -528,22 +529,22 @@ snmpe_recvmsg(int fd, short sig, void *arg)
 		}
 	}
 
-	snmpe_dispatchmsg(msg, fd);
+	snmpe_dispatchmsg(msg);
 }
 
 void
-snmpe_dispatchmsg(struct snmp_message *msg, int sock)
+snmpe_dispatchmsg(struct snmp_message *msg)
 {
 	if (snmpe_parsevarbinds(msg) == 1)
 		return;
 
 	/* not dispatched to subagent; respond directly */
 	msg->sm_context = SNMP_C_GETRESP;
-	snmpe_response(sock, msg);
+	snmpe_response(msg);
 }
 
 void
-snmpe_response(int fd, struct snmp_message *msg)
+snmpe_response(struct snmp_message *msg)
 {
 	struct snmp_stats	*stats = &snmpd_env->sc_stats;
 	u_int8_t		*ptr = NULL;
@@ -580,7 +581,7 @@ snmpe_response(int fd, struct snmp_message *msg)
 		goto done;
 
 	usm_finalize_digest(msg, ptr, len);
-	len = sendtofrom(fd, ptr, len, 0,
+	len = sendtofrom(msg->sm_sock, ptr, len, 0,
 	    (struct sockaddr *)&msg->sm_ss, msg->sm_slen,
 	    (struct sockaddr *)&msg->sm_local_ss, msg->sm_local_slen);
 	if (len != -1)