Extend init method to allow 0-length client IDs if MQTTv311 is set

mqtt/include/mqtt.h

@@ -131,7 +131,7 @@ typedef struct  {
 #define MQTT_EVENT_TYPE_PUBLISH_CONTINUATION 8
 
 void ICACHE_FLASH_ATTR MQTT_InitConnection(MQTT_Client *mqttClient, uint8_t* host, uint32_t port, uint8_t security);
-void ICACHE_FLASH_ATTR MQTT_InitClient(MQTT_Client *mqttClient, uint8_t* client_id, uint8_t* client_user, uint8_t* client_pass, uint32_t keepAliveTime, uint8_t cleanSession);
+BOOL ICACHE_FLASH_ATTR MQTT_InitClient(MQTT_Client *mqttClient, uint8_t* client_id, uint8_t* client_user, uint8_t* client_pass, uint32_t keepAliveTime, uint8_t cleanSession);
 void ICACHE_FLASH_ATTR MQTT_DeleteClient(MQTT_Client *mqttClient);
 void ICACHE_FLASH_ATTR MQTT_InitLWT(MQTT_Client *mqttClient, uint8_t* will_topic, uint8_t* will_msg, uint8_t will_qos, uint8_t will_retain);
 void ICACHE_FLASH_ATTR MQTT_OnConnected(MQTT_Client *mqttClient, MqttCallback connectedCb);

mqtt/mqtt.c

@@ -59,6 +59,10 @@ unsigned int default_private_key_len = 0;
 
 os_event_t mqtt_procTaskQueue[MQTT_TASK_QUEUE_SIZE];
 
+#ifdef PROTOCOL_NAMEv311
+LOCAL uint8_t zero_len_id[2] = { 0, 0 };
+#endif
+
 LOCAL void ICACHE_FLASH_ATTR
 mqtt_dns_found(const char *name, ip_addr_t *ipaddr, void *arg)
 {
@@ -227,7 +231,13 @@ mqtt_client_delete(MQTT_Client *mqttClient)
   }
 
   if (mqttClient->connect_info.client_id != NULL) {
+#ifdef PROTOCOL_NAMEv311
+    /* Don't attempt to free if it's the zero_len array */
+    if ( ((uint8_t*)mqttClient->connect_info.client_id) != zero_len_id )
+      os_free(mqttClient->connect_info.client_id);
+#else
     os_free(mqttClient->connect_info.client_id);
+#endif
     mqttClient->connect_info.client_id = NULL;
   }
 
@@ -786,7 +796,7 @@ MQTT_InitConnection(MQTT_Client *mqttClient, uint8_t* host, uint32_t port, uint8
   * @param  client_pass:MQTT keep alive timer, in second
   * @retval None
   */
-void ICACHE_FLASH_ATTR
+BOOL ICACHE_FLASH_ATTR
 MQTT_InitClient(MQTT_Client *mqttClient, uint8_t* client_id, uint8_t* client_user, uint8_t* client_pass, uint32_t keepAliveTime, uint8_t cleanSession)
 {
   uint32_t temp;
@@ -794,10 +804,33 @@ MQTT_InitClient(MQTT_Client *mqttClient, uint8_t* client_id, uint8_t* client_use
 
   os_memset(&mqttClient->connect_info, 0, sizeof(mqtt_connect_info_t));
 
-  temp = os_strlen(client_id);
-  mqttClient->connect_info.client_id = (uint8_t*)os_zalloc(temp + 1);
-  os_strcpy(mqttClient->connect_info.client_id, client_id);
-  mqttClient->connect_info.client_id[temp] = 0;
+  if ( !client_id )
+  {
+    /* Should be allowed by broker, but clean session flag must be set. */
+  #ifdef PROTOCOL_NAMEv311
+    if (cleanSession)
+    {
+      mqttClient->connect_info.client_id = zero_len_id;
+    } else {
+      MQTT_INFO("cleanSession must be set to use 0 length client_id\r\n");
+      return false;
+    }
+    /* Not supported. Return. */
+  #else
+    MQTT_INFO("Client ID required for MQTT < 3.1.1!\r\n");
+    return false;
+  #endif
+ }
+
+  /* If connect_info's client_id is still NULL and we get here, we can        *
+   * assume the passed client_id is non-NULL.                                 */
+  if ( !(mqttClient->connect_info.client_id) )
+  {
+    temp = os_strlen(client_id);
+    mqttClient->connect_info.client_id = (uint8_t*)os_zalloc(temp + 1);
+    os_strcpy(mqttClient->connect_info.client_id, client_id);
+    mqttClient->connect_info.client_id[temp] = 0;
+  }
 
   if (client_user)
   {
@@ -831,6 +864,7 @@ MQTT_InitClient(MQTT_Client *mqttClient, uint8_t* client_id, uint8_t* client_use
 
   system_os_task(MQTT_Task, MQTT_TASK_PRIO, mqtt_procTaskQueue, MQTT_TASK_QUEUE_SIZE);
   system_os_post(MQTT_TASK_PRIO, 0, (os_param_t)mqttClient);
+  return true;
 }
 void ICACHE_FLASH_ATTR
 MQTT_InitLWT(MQTT_Client *mqttClient, uint8_t* will_topic, uint8_t* will_msg, uint8_t will_qos, uint8_t will_retain)

mqtt/mqtt_msg.c

@@ -319,13 +319,27 @@ mqtt_message_t* ICACHE_FLASH_ATTR mqtt_msg_connect(mqtt_connection_t* connection
   if (info->clean_session)
     variable_header->flags |= MQTT_CONNECT_FLAG_CLEAN_SESSION;
 
-  if (info->client_id != NULL && info->client_id[0] != '\0')
+  if (info->client_id == NULL)
   {
-    if (append_string(connection, info->client_id, strlen(info->client_id)) < 0)
-      return fail_message(connection);
+    /* Never allowed */
+    return fail_message(connection);
+  }
+  else if (info->client_id[0] == '\0')
+  {
+#ifdef PROTOCOL_NAMEv311
+    /* Allowed. Format 0 Length ID */
+    append_string(connection, info->client_id, 2) ;
+#else
+    /* 0 Length not allowed */
+    return fail_message(connection);
+#endif
   }
   else
-    return fail_message(connection);
+  {
+    /* No 0 data and at least 1 long. Good to go. */
+    if(append_string(connection, info->client_id, strlen(info->client_id)) < 0)
+      return fail_message(connection);
+  }
 
   if (info->will_topic != NULL && info->will_topic[0] != '\0')
   {

user/user_main.c

@@ -109,7 +109,11 @@ static void ICACHE_FLASH_ATTR app_init(void)
   MQTT_InitConnection(&mqttClient, MQTT_HOST, MQTT_PORT, DEFAULT_SECURITY);
   //MQTT_InitConnection(&mqttClient, "192.168.11.122", 1880, 0);
 
-  MQTT_InitClient(&mqttClient, MQTT_CLIENT_ID, MQTT_USER, MQTT_PASS, MQTT_KEEPALIVE, MQTT_CLEAN_SESSION);
+  if ( !MQTT_InitClient(&mqttClient, MQTT_CLIENT_ID, MQTT_USER, MQTT_PASS, MQTT_KEEPALIVE, MQTT_CLEAN_SESSION) )
+  {
+    INFO("Failed to initialize properly. Check MQTT version.\r\n");
+    return;
+  }
   //MQTT_InitClient(&mqttClient, "client_id", "user", "pass", 120, 1);
   MQTT_InitLWT(&mqttClient, "/lwt", "offline", 0, 0);
   MQTT_OnConnected(&mqttClient, mqttConnectedCb);