Re-do r240271:

- Set IP_RECVDSTADDR sockopt on the socket only in case if
  it is INADDR_ANY bound.
- Supply IP_SENDSRCADDR control message only if we did receive
  IP_RECVDSTADDR control message.

This fixes operation of snmpd bound to a specific local IP address.

PR:		bin/171279

2 files changed, 17 insertions, 8 deletions

diff --git a/contrib/bsnmp/snmpd/main.c b/contrib/bsnmp/snmpd/main.c
index 6fdc6d3..e7257b5 100644
--- a/contrib/bsnmp/snmpd/main.c
+++ b/contrib/bsnmp/snmpd/main.c
@@ -1203,6 +1203,8 @@ snmpd_input(struct port_input *pi, struct tport *tport)
 
 		ret = recv_stream(pi);
 	} else {
+		struct in_addr *laddr;
+
 		memset(cbuf, 0, CMSG_SPACE(sizeof(struct in_addr)));
 		msg.msg_control = cbuf;
 		msg.msg_controllen = CMSG_SPACE(sizeof(struct in_addr));
@@ -1210,8 +1212,14 @@ snmpd_input(struct port_input *pi, struct tport *tport)
 		cmsgp->cmsg_len = CMSG_LEN(sizeof(struct in_addr));
 		cmsgp->cmsg_level = IPPROTO_IP;
 		cmsgp->cmsg_type = IP_SENDSRCADDR;
+		laddr = (struct in_addr *)CMSG_DATA(cmsgp);
 		
-		ret = recv_dgram(pi, (struct in_addr *)CMSG_DATA(cmsgp));
+		ret = recv_dgram(pi, laddr);
+
+		if (laddr->s_addr == 0) {
+			msg.msg_control = NULL;
+			msg.msg_controllen = 0;
+		}
 	}
 
 	if (ret == -1)
diff --git a/contrib/bsnmp/snmpd/trans_udp.c b/contrib/bsnmp/snmpd/trans_udp.c
index 0a119d2..3faef41 100644
--- a/contrib/bsnmp/snmpd/trans_udp.c
+++ b/contrib/bsnmp/snmpd/trans_udp.c
@@ -109,13 +109,6 @@ udp_init_port(struct tport *tp)
 		syslog(LOG_ERR, "creating UDP socket: %m");
 		return (SNMP_ERR_RES_UNAVAIL);
 	}
-	if (setsockopt(p->input.fd, IPPROTO_IP, IP_RECVDSTADDR, &on,
-	    sizeof(on)) == -1) {
-		syslog(LOG_ERR, "setsockopt(IP_RECVDSTADDR): %m");
-		close(p->input.fd);
-		p->input.fd = -1;
-		return (SNMP_ERR_GENERR);
-	}
 	ip = (p->addr[0] << 24) | (p->addr[1] << 16) | (p->addr[2] << 8) |
 	    p->addr[3];
 	memset(&addr, 0, sizeof(addr));
@@ -123,6 +116,14 @@ udp_init_port(struct tport *tp)
 	addr.sin_port = htons(p->port);
 	addr.sin_family = AF_INET;
 	addr.sin_len = sizeof(addr);
+	if (addr.sin_addr.s_addr == INADDR_ANY &&
+	    setsockopt(p->input.fd, IPPROTO_IP, IP_RECVDSTADDR, &on,
+	    sizeof(on)) == -1) {
+		syslog(LOG_ERR, "setsockopt(IP_RECVDSTADDR): %m");
+		close(p->input.fd);
+		p->input.fd = -1;
+		return (SNMP_ERR_GENERR);
+	}
 	if (bind(p->input.fd, (struct sockaddr *)&addr, sizeof(addr))) {
 		if (errno == EADDRNOTAVAIL) {
 			close(p->input.fd);