Fix some error handling related to the `bind_interface` option.

ChangeLog.txt

@@ -2,6 +2,7 @@ Broker:
 - Fix $SYS messages being expired after 60 seconds and hence unchanged values
   disappearing.
 - Fix some retained topic memory not being cleared immediately after used.
+- Fix error handling related to the `bind_interface` option.
 
 2.0.15 - 2022-08-16
 ===================

src/net.c

@@ -622,6 +622,8 @@ static int net__bind_interface(struct mosquitto__listener *listener, struct addr
 	 * matching interface in the later bind().
 	 */
 	struct ifaddrs *ifaddr, *ifa;
+	bool have_interface = false;
+
 	if(getifaddrs(&ifaddr) < 0){
 		net__print_error(MOSQ_LOG_ERR, "Error: %s");
 		return MOSQ_ERR_ERRNO;
@@ -632,16 +634,17 @@ static int net__bind_interface(struct mosquitto__listener *listener, struct addr
 			continue;
 		}
 
-		if(!strcasecmp(listener->bind_interface, ifa->ifa_name)
+		if(!strcasecmp(listener->bind_interface, ifa->ifa_name)){
-				&& ifa->ifa_addr->sa_family == rp->ai_addr->sa_family){
+			have_interface = true;
 
+			if(ifa->ifa_addr->sa_family == rp->ai_addr->sa_family){
 				if(rp->ai_addr->sa_family == AF_INET){
 					if(listener->host &&
 							memcmp(&((struct sockaddr_in *)rp->ai_addr)->sin_addr,
 								&((struct sockaddr_in *)ifa->ifa_addr)->sin_addr,
 								sizeof(struct in_addr))){
 
-					log__printf(NULL, MOSQ_LOG_WARNING, "Warning: Interface address for %s does not match specified listener address (%s).",
+						log__printf(NULL, MOSQ_LOG_ERR, "Error: Interface address for %s does not match specified listener address (%s).",
 								listener->bind_interface, listener->host);
 						return MOSQ_ERR_INVAL;
 					}else{
@@ -658,7 +661,7 @@ static int net__bind_interface(struct mosquitto__listener *listener, struct addr
 								&((struct sockaddr_in6 *)ifa->ifa_addr)->sin6_addr,
 								sizeof(struct in6_addr))){
 
-					log__printf(NULL, MOSQ_LOG_WARNING, "Warning: Interface address for %s does not match specified listener address (%s).",
+						log__printf(NULL, MOSQ_LOG_ERR, "Error: Interface address for %s does not match specified listener address (%s).",
 								listener->bind_interface, listener->host);
 						return MOSQ_ERR_INVAL;
 					}else{
@@ -671,11 +674,17 @@ static int net__bind_interface(struct mosquitto__listener *listener, struct addr
 				}
 			}
 		}
+	}
 	freeifaddrs(ifaddr);
+	if(have_interface){
 		log__printf(NULL, MOSQ_LOG_WARNING, "Warning: Interface %s does not support %s configuration.",
 					listener->bind_interface, rp->ai_addr->sa_family == AF_INET ? "IPv4" : "IPv6");
+		return MOSQ_ERR_NOT_SUPPORTED;
+	}else{
+		log__printf(NULL, MOSQ_LOG_ERR, "Error: Interface %s does not exist.", listener->bind_interface);
 		return MOSQ_ERR_NOT_FOUND;
 	}
+}
 #endif
 
 
@@ -756,11 +765,16 @@ static int net__socket_listen_tcp(struct mosquitto__listener *listener)
 		if(listener->bind_interface){
 			/* It might be possible that an interface does not support all relevant sa_families.
 			 * We should successfully find at least one. */
-			if(net__bind_interface(listener, rp)){
+			rc = net__bind_interface(listener, rp);
+			if(rc){
 				COMPAT_CLOSE(sock);
 				listener->sock_count--;
+				if(rc == MOSQ_ERR_NOT_FOUND || rc == MOSQ_ERR_INVAL){
+					return rc;
+				}else{
 					continue;
 				}
+			}
 			interface_bound = true;
 		}
 #endif

test/mosq_test.py

@@ -70,7 +70,7 @@ def start_broker(filename, cmd=None, port=0, use_conf=False, expect_fail=False,
         print("FAIL: unable to start broker: %s" % errs)
         raise IOError
     else:
-        return None
+        return broker
 
 def start_client(filename, cmd, env, port=1888):
     if cmd is None: