Add MOSQ_OPT_BIND_ADDRESS.

This allows setting of a bind address independently of the
`mosquitto_connect*()` call.

ChangeLog.txt

@@ -75,6 +75,8 @@ Client library:
 - Fix send quota being incorrecly reset on reconnect. Closes #1822.
 - Don't use logging until log mutex is initialised. Closes #1819.
 - Fix missing mach/mach_time.h header on OS X. Closes #1831.
+- Add MOSQ_OPT_BIND_ADDRESS to allow setting of a bind address independently
+ of the `mosquitto_connect*()` call.
 
 Clients:
 - Add timeout return code (27) for `mosquitto_sub -W <secs>` and

include/mosquitto.h

@@ -118,6 +118,7 @@ enum mosq_opt_t {
  MOSQ_OPT_TLS_OCSP_REQUIRED = 9,
  MOSQ_OPT_TLS_ALPN = 10,
  MOSQ_OPT_TCP_NODELAY = 11,
+ MOSQ_OPT_BIND_ADDRESS = 12,
 };
 
 
@@ -1485,6 +1486,9 @@ libmosq_EXPORT int mosquitto_int_option(struct mosquitto *mosq, enum mosq_opt_t
  * services available on a single TLS port, such as both MQTT
  * and WebSockets, use this option to configure the ALPN
  * option for the connection.
+ *
+ * MOSQ_OPT_BIND_ADDRESS - Set the hostname or ip address of the local network
+ * interface to bind to when connecting.
  */
 libmosq_EXPORT int mosquitto_string_option(struct mosquitto *mosq, enum mosq_opt_t option, const char *value);
 

lib/connect.c

@@ -33,10 +33,10 @@ and the Eclipse Distribution License is available at
 static char alphanum[] = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
 
 static int mosquitto__reconnect(struct mosquitto *mosq, bool blocking, const mosquitto_property *properties);
-static int mosquitto__connect_init(struct mosquitto *mosq, const char *host, int port, int keepalive, const char *bind_address);
+static int mosquitto__connect_init(struct mosquitto *mosq, const char *host, int port, int keepalive);
 
 
-static int mosquitto__connect_init(struct mosquitto *mosq, const char *host, int port, int keepalive, const char *bind_address)
+static int mosquitto__connect_init(struct mosquitto *mosq, const char *host, int port, int keepalive)
 {
  int i;
  int rc;
@@ -70,12 +70,6 @@ static int mosquitto__connect_init(struct mosquitto *mosq, const char *host, int
  if(!mosq->host) return MOSQ_ERR_NOMEM;
  mosq->port = port;
 
- mosquitto__free(mosq->bind_address);
- if(bind_address){
- mosq->bind_address = mosquitto__strdup(bind_address);
- if(!mosq->bind_address) return MOSQ_ERR_NOMEM;
- }
-
  mosq->keepalive = keepalive;
  mosq->msgs_in.inflight_quota = mosq->msgs_in.inflight_maximum;
  mosq->msgs_out.inflight_quota = mosq->msgs_out.inflight_maximum;
@@ -100,12 +94,15 @@ int mosquitto_connect_bind_v5(struct mosquitto *mosq, const char *host, int port
 {
  int rc;
 
+ rc = mosquitto_string_option(mosq, MOSQ_OPT_BIND_ADDRESS, bind_address);
+ if(rc) return rc;
+
  if(properties){
  rc = mosquitto_property_check_all(CMD_CONNECT, properties);
  if(rc) return rc;
  }
 
- rc = mosquitto__connect_init(mosq, host, port, keepalive, bind_address);
+ rc = mosquitto__connect_init(mosq, host, port, keepalive);
  if(rc) return rc;
 
  mosquitto__set_state(mosq, mosq_cs_new);
@@ -122,7 +119,12 @@ int mosquitto_connect_async(struct mosquitto *mosq, const char *host, int port,
 
 int mosquitto_connect_bind_async(struct mosquitto *mosq, const char *host, int port, int keepalive, const char *bind_address)
 {
- int rc = mosquitto__connect_init(mosq, host, port, keepalive, bind_address);
+ int rc;
+
+ rc = mosquitto_string_option(mosq, MOSQ_OPT_BIND_ADDRESS, bind_address);
+ if(rc) return rc;
+
+ rc = mosquitto__connect_init(mosq, host, port, keepalive);
  if(rc) return rc;
 
  return mosquitto__reconnect(mosq, false, NULL);

lib/options.c

@@ -321,6 +321,20 @@ int mosquitto_string_option(struct mosquitto *mosq, enum mosq_opt_t option, cons
 #endif
  break;
 
+ case MOSQ_OPT_BIND_ADDRESS:
+ mosquitto__free(mosq->bind_address);
+ if(value){
+ mosq->bind_address = mosquitto__strdup(value);
+ if(mosq->bind_address){
+ return MOSQ_ERR_SUCCESS;
+ }else{
+ return MOSQ_ERR_NOMEM;
+ }
+ }else{
+ return MOSQ_ERR_SUCCESS;
+ }
+
+
  default:
  return MOSQ_ERR_INVAL;
  }