int _mosquitto_will_set(struct mosquitto *mosq, const char *topic, int payloadlen, const void *payload, int qos, bool retain) { int rc = MOSQ_ERR_SUCCESS; if(!mosq || !topic) return MOSQ_ERR_INVAL; if(payloadlen < 0 || payloadlen > MQTT_MAX_PAYLOAD) return MOSQ_ERR_PAYLOAD_SIZE; if(payloadlen > 0 && !payload) return MOSQ_ERR_INVAL; if(_mosquitto_topic_wildcard_pos_check(topic)) return MOSQ_ERR_INVAL; if(mosq->will){ //先删除原来老的will相关的内容,再重新创立 if(mosq->will->topic){ _mosquitto_free(mosq->will->topic); mosq->will->topic = NULL; } if(mosq->will->payload){ _mosquitto_free(mosq->will->payload); mosq->will->payload = NULL; } _mosquitto_free(mosq->will); mosq->will = NULL; } mosq->will = _mosquitto_calloc(1, sizeof(struct mosquitto_message)); if(!mosq->will) return MOSQ_ERR_NOMEM; mosq->will->topic = _mosquitto_strdup(topic); if(!mosq->will->topic){ rc = MOSQ_ERR_NOMEM; goto cleanup; } mosq->will->payloadlen = payloadlen; if(mosq->will->payloadlen > 0){ if(!payload){ rc = MOSQ_ERR_INVAL; goto cleanup; } mosq->will->payload = _mosquitto_malloc(sizeof(char)*mosq->will->payloadlen); if(!mosq->will->payload){ rc = MOSQ_ERR_NOMEM; goto cleanup; } memcpy(mosq->will->payload, payload, payloadlen); } mosq->will->qos = qos; mosq->will->retain = retain; return MOSQ_ERR_SUCCESS; cleanup: if(mosq->will){ if(mosq->will->topic) _mosquitto_free(mosq->will->topic); if(mosq->will->payload) _mosquitto_free(mosq->will->payload); } _mosquitto_free(mosq->will); mosq->will = NULL; return rc; }
int mosquitto_unsubscribe(struct mosquitto *mosq, int *mid, const char *sub) { if(!mosq) return MOSQ_ERR_INVAL; if(mosq->sock == INVALID_SOCKET) return MOSQ_ERR_NO_CONN; if(_mosquitto_topic_wildcard_pos_check(sub)) return MOSQ_ERR_INVAL; return _mosquitto_send_unsubscribe(mosq, mid, false, sub); }
int mqtt3_handle_unsubscribe(struct mosquitto_db *db, struct mosquitto *context) { uint16_t mid; char *sub; if(!context) return MOSQ_ERR_INVAL; _mosquitto_log_printf(NULL, MOSQ_LOG_DEBUG, "Received UNSUBSCRIBE from %s", context->id); if(context->protocol == mosq_p_mqtt311){ if((context->in_packet.command&0x0F) != 0x02){ return MOSQ_ERR_PROTOCOL; } } if(_mosquitto_read_uint16(&context->in_packet, &mid)) return 1; while(context->in_packet.pos < context->in_packet.remaining_length){ sub = NULL; if(_mosquitto_read_string(&context->in_packet, &sub)){ return 1; } if(sub){ if(!strlen(sub)){ _mosquitto_log_printf(NULL, MOSQ_LOG_INFO, "Empty unsubscription string from %s, disconnecting.", context->id); _mosquitto_free(sub); return 1; } if(_mosquitto_topic_wildcard_pos_check(sub)){ _mosquitto_log_printf(NULL, MOSQ_LOG_INFO, "Invalid unsubscription string from %s, disconnecting.", context->id); _mosquitto_free(sub); return 1; } _mosquitto_log_printf(NULL, MOSQ_LOG_DEBUG, "\t%s", sub); mqtt3_sub_remove(db, context, sub, &db->subs); _mosquitto_log_printf(NULL, MOSQ_LOG_UNSUBSCRIBE, "%s %s", context->id, sub); _mosquitto_free(sub); } } #ifdef WITH_PERSISTENCE db->persistence_changes++; #endif return _mosquitto_send_command_with_mid(context, UNSUBACK, mid, false); }
int mqtt3_handle_connect(struct mosquitto_db *db, struct mosquitto *context) { char *protocol_name = NULL; uint8_t protocol_version; uint8_t connect_flags; char *client_id = NULL; char *will_payload = NULL, *will_topic = NULL; uint16_t will_payloadlen; struct mosquitto_message *will_struct = NULL; uint8_t will, will_retain, will_qos, clean_session; uint8_t username_flag, password_flag; char *username = NULL, *password = NULL; int i; int rc; struct _mosquitto_acl_user *acl_tail; struct mosquitto_client_msg *msg_tail, *msg_prev; int slen; #ifdef WITH_TLS X509 *client_cert; X509_NAME *name; X509_NAME_ENTRY *name_entry; #endif struct _clientid_index_hash *find_cih; struct _clientid_index_hash *new_cih; #ifdef WITH_SYS_TREE g_connection_count++; #endif /* Don't accept multiple CONNECT commands. */ if(context->state != mosq_cs_new){ mqtt3_context_disconnect(db, context); return MOSQ_ERR_PROTOCOL; } if(_mosquitto_read_string(&context->in_packet, &protocol_name)){ mqtt3_context_disconnect(db, context); return 1; } if(!protocol_name){ mqtt3_context_disconnect(db, context); return 3; } if(_mosquitto_read_byte(&context->in_packet, &protocol_version)){ mqtt3_context_disconnect(db, context); return 1; } if(!strcmp(protocol_name, PROTOCOL_NAME_v31)){ if((protocol_version&0x7F) != PROTOCOL_VERSION_v31){ if(db->config->connection_messages == true){ _mosquitto_log_printf(NULL, MOSQ_LOG_INFO, "Invalid protocol version %d in CONNECT from %s.", protocol_version, context->address); } _mosquitto_send_connack(context, CONNACK_REFUSED_PROTOCOL_VERSION); mqtt3_context_disconnect(db, context); _mosquitto_free(protocol_name); return MOSQ_ERR_PROTOCOL; } context->protocol = mosq_p_mqtt31; }else if(!strcmp(protocol_name, PROTOCOL_NAME_v311)){ if((protocol_version&0x7F) != PROTOCOL_VERSION_v311){ if(db->config->connection_messages == true){ _mosquitto_log_printf(NULL, MOSQ_LOG_INFO, "Invalid protocol version %d in CONNECT from %s.", protocol_version, context->address); } _mosquitto_send_connack(context, CONNACK_REFUSED_PROTOCOL_VERSION); mqtt3_context_disconnect(db, context); _mosquitto_free(protocol_name); return MOSQ_ERR_PROTOCOL; } if((context->in_packet.command&0x0F) != 0x00){ /* Reserved flags not set to 0, must disconnect. */ mqtt3_context_disconnect(db, context); _mosquitto_free(protocol_name); return MOSQ_ERR_PROTOCOL; } context->protocol = mosq_p_mqtt311; }else{ if(db->config->connection_messages == true){ _mosquitto_log_printf(NULL, MOSQ_LOG_INFO, "Invalid protocol \"%s\" in CONNECT from %s.", protocol_name, context->address); } _mosquitto_free(protocol_name); mqtt3_context_disconnect(db, context); return MOSQ_ERR_PROTOCOL; } _mosquitto_free(protocol_name); if(_mosquitto_read_byte(&context->in_packet, &connect_flags)){ mqtt3_context_disconnect(db, context); return 1; } clean_session = connect_flags & 0x02; will = connect_flags & 0x04; will_qos = (connect_flags & 0x18) >> 3; if(will_qos == 3){ _mosquitto_log_printf(NULL, MOSQ_LOG_INFO, "Invalid Will QoS in CONNECT from %s.", context->address); mqtt3_context_disconnect(db, context); return MOSQ_ERR_PROTOCOL; } will_retain = connect_flags & 0x20; password_flag = connect_flags & 0x40; username_flag = connect_flags & 0x80; if(_mosquitto_read_uint16(&context->in_packet, &(context->keepalive))){ mqtt3_context_disconnect(db, context); return 1; } if(_mosquitto_read_string(&context->in_packet, &client_id)){ mqtt3_context_disconnect(db, context); return 1; } slen = strlen(client_id); #ifdef WITH_STRICT_PROTOCOL if(slen > 23 || slen == 0){ #else if(slen == 0){ #endif if(context->protocol == mosq_p_mqtt31){ _mosquitto_free(client_id); _mosquitto_send_connack(context, CONNACK_REFUSED_IDENTIFIER_REJECTED); mqtt3_context_disconnect(db, context); return MOSQ_ERR_PROTOCOL; }else{ /* mqtt311 */ _mosquitto_free(client_id); if(clean_session == 0){ _mosquitto_send_connack(context, CONNACK_REFUSED_IDENTIFIER_REJECTED); mqtt3_context_disconnect(db, context); return MOSQ_ERR_PROTOCOL; } if(db->config->allow_zero_length_clientid == true){ client_id = (char *)_mosquitto_calloc(65 + db->config->auto_id_prefix_len, sizeof(char)); if(!client_id){ mqtt3_context_disconnect(db, context); return MOSQ_ERR_NOMEM; } memcpy(client_id, db->config->auto_id_prefix, db->config->auto_id_prefix_len); for(i=0; i<64; i++){ client_id[i+db->config->auto_id_prefix_len] = (rand()%73)+48; } client_id[i] = '\0'; }else{ _mosquitto_send_connack(context, CONNACK_REFUSED_IDENTIFIER_REJECTED); mqtt3_context_disconnect(db, context); return MOSQ_ERR_PROTOCOL; } } } /* clientid_prefixes check */ if(db->config->clientid_prefixes){ if(strncmp(db->config->clientid_prefixes, client_id, strlen(db->config->clientid_prefixes))){ _mosquitto_free(client_id); _mosquitto_send_connack(context, CONNACK_REFUSED_NOT_AUTHORIZED); mqtt3_context_disconnect(db, context); return MOSQ_ERR_SUCCESS; } } if(will){ will_struct = _mosquitto_calloc(1, sizeof(struct mosquitto_message)); if(!will_struct){ mqtt3_context_disconnect(db, context); rc = MOSQ_ERR_NOMEM; goto handle_connect_error; } if(_mosquitto_read_string(&context->in_packet, &will_topic)){ mqtt3_context_disconnect(db, context); rc = 1; goto handle_connect_error; } if(strlen(will_topic) == 0){ mqtt3_context_disconnect(db, context); rc = 1; goto handle_connect_error; } if(_mosquitto_topic_wildcard_pos_check(will_topic)){ mqtt3_context_disconnect(db, context); rc = 1; goto handle_connect_error; } if(_mosquitto_read_uint16(&context->in_packet, &will_payloadlen)){ mqtt3_context_disconnect(db, context); rc = 1; goto handle_connect_error; } if(will_payloadlen > 0){ will_payload = _mosquitto_malloc(will_payloadlen); if(!will_payload){ mqtt3_context_disconnect(db, context); rc = 1; goto handle_connect_error; } rc = _mosquitto_read_bytes(&context->in_packet, will_payload, will_payloadlen); if(rc){ mqtt3_context_disconnect(db, context); rc = 1; goto handle_connect_error; } } }else{ if(context->protocol == mosq_p_mqtt311){ if(will_qos != 0 || will_retain != 0){ mqtt3_context_disconnect(db, context); rc = MOSQ_ERR_PROTOCOL; goto handle_connect_error; } } } if(username_flag){ rc = _mosquitto_read_string(&context->in_packet, &username); if(rc == MOSQ_ERR_SUCCESS){ if(password_flag){ rc = _mosquitto_read_string(&context->in_packet, &password); if(rc == MOSQ_ERR_NOMEM){ rc = MOSQ_ERR_NOMEM; goto handle_connect_error; }else if(rc == MOSQ_ERR_PROTOCOL){ if(context->protocol == mosq_p_mqtt31){ /* Password flag given, but no password. Ignore. */ password_flag = 0; }else if(context->protocol == mosq_p_mqtt311){ mqtt3_context_disconnect(db, context); rc = MOSQ_ERR_PROTOCOL; goto handle_connect_error; } } } }else if(rc == MOSQ_ERR_NOMEM){ rc = MOSQ_ERR_NOMEM; goto handle_connect_error; }else{ if(context->protocol == mosq_p_mqtt31){ /* Username flag given, but no username. Ignore. */ username_flag = 0; }else if(context->protocol == mosq_p_mqtt311){ mqtt3_context_disconnect(db, context); rc = MOSQ_ERR_PROTOCOL; goto handle_connect_error; } } }else{ if(context->protocol == mosq_p_mqtt311){ if(password_flag){ /* username_flag == 0 && password_flag == 1 is forbidden */ mqtt3_context_disconnect(db, context); rc = MOSQ_ERR_PROTOCOL; goto handle_connect_error; } } } #ifdef WITH_TLS if(context->listener->use_identity_as_username){ if(!context->ssl){ _mosquitto_send_connack(context, CONNACK_REFUSED_BAD_USERNAME_PASSWORD); mqtt3_context_disconnect(db, context); rc = MOSQ_ERR_SUCCESS; goto handle_connect_error; } #ifdef REAL_WITH_TLS_PSK if(context->listener->psk_hint){ /* Client should have provided an identity to get this far. */ if(!context->username){ _mosquitto_send_connack(context, CONNACK_REFUSED_BAD_USERNAME_PASSWORD); mqtt3_context_disconnect(db, context); rc = MOSQ_ERR_SUCCESS; goto handle_connect_error; } }else{ #endif /* REAL_WITH_TLS_PSK */ client_cert = SSL_get_peer_certificate(context->ssl); if(!client_cert){ _mosquitto_send_connack(context, CONNACK_REFUSED_BAD_USERNAME_PASSWORD); mqtt3_context_disconnect(db, context); rc = MOSQ_ERR_SUCCESS; goto handle_connect_error; } name = X509_get_subject_name(client_cert); if(!name){ _mosquitto_send_connack(context, CONNACK_REFUSED_BAD_USERNAME_PASSWORD); mqtt3_context_disconnect(db, context); rc = MOSQ_ERR_SUCCESS; goto handle_connect_error; } i = X509_NAME_get_index_by_NID(name, NID_commonName, -1); if(i == -1){ _mosquitto_send_connack(context, CONNACK_REFUSED_BAD_USERNAME_PASSWORD); mqtt3_context_disconnect(db, context); rc = MOSQ_ERR_SUCCESS; goto handle_connect_error; } name_entry = X509_NAME_get_entry(name, i); context->username = _mosquitto_strdup((char *)ASN1_STRING_data(name_entry->value)); if(!context->username){ rc = MOSQ_ERR_SUCCESS; goto handle_connect_error; } #ifdef REAL_WITH_TLS_PSK } #endif /* REAL_WITH_TLS_PSK */ }else{ #endif /* WITH_TLS */ if(username_flag){ rc = mosquitto_unpwd_check(db, username, password); switch(rc){ case MOSQ_ERR_SUCCESS: break; case MOSQ_ERR_AUTH: _mosquitto_send_connack(context, CONNACK_REFUSED_BAD_USERNAME_PASSWORD); mqtt3_context_disconnect(db, context); rc = MOSQ_ERR_SUCCESS; goto handle_connect_error; break; default: mqtt3_context_disconnect(db, context); rc = MOSQ_ERR_SUCCESS; goto handle_connect_error; break; } context->username = username; context->password = password; username = NULL; /* Avoid free() in error: below. */ password = NULL; } if(!username_flag && db->config->allow_anonymous == false){ _mosquitto_send_connack(context, CONNACK_REFUSED_NOT_AUTHORIZED); mqtt3_context_disconnect(db, context); rc = MOSQ_ERR_SUCCESS; goto handle_connect_error; } #ifdef WITH_TLS } #endif /* Find if this client already has an entry. This must be done *after* any security checks. */ HASH_FIND_STR(db->clientid_index_hash, client_id, find_cih); if(find_cih){ i = find_cih->db_context_index; /* Found a matching client */ if(db->contexts[i]->sock == -1){ /* Client is reconnecting after a disconnect */ /* FIXME - does anything else need to be done here? */ }else{ /* Client is already connected, disconnect old version */ if(db->config->connection_messages == true){ _mosquitto_log_printf(NULL, MOSQ_LOG_ERR, "Client %s already connected, closing old connection.", client_id); } } db->contexts[i]->clean_session = clean_session; mqtt3_context_cleanup(db, db->contexts[i], false); db->contexts[i]->state = mosq_cs_connected; db->contexts[i]->address = _mosquitto_strdup(context->address); db->contexts[i]->sock = context->sock; db->contexts[i]->listener = context->listener; db->contexts[i]->last_msg_in = mosquitto_time(); db->contexts[i]->last_msg_out = mosquitto_time(); db->contexts[i]->keepalive = context->keepalive; db->contexts[i]->pollfd_index = context->pollfd_index; #ifdef WITH_TLS db->contexts[i]->ssl = context->ssl; #endif if(context->username){ db->contexts[i]->username = _mosquitto_strdup(context->username); } context->sock = -1; #ifdef WITH_TLS context->ssl = NULL; #endif context->state = mosq_cs_disconnecting; context = db->contexts[i]; if(context->msgs){ mqtt3_db_message_reconnect_reset(context); } } context->id = client_id; client_id = NULL; context->clean_session = clean_session; context->ping_t = 0; context->is_dropping = false; if((protocol_version&0x80) == 0x80){ context->is_bridge = true; } /* Remove any queued messages that are no longer allowed through ACL, * assuming a possible change of username. */ msg_tail = context->msgs; msg_prev = NULL; while(msg_tail){ if(msg_tail->direction == mosq_md_out){ if(mosquitto_acl_check(db, context, msg_tail->store->msg.topic, MOSQ_ACL_READ) == MOSQ_ERR_ACL_DENIED){ msg_tail->store->ref_count--; if(msg_prev){ msg_prev->next = msg_tail->next; _mosquitto_free(msg_tail); msg_tail = msg_prev->next; }else{ context->msgs = context->msgs->next; _mosquitto_free(msg_tail); msg_tail = context->msgs; } }else{ msg_prev = msg_tail; msg_tail = msg_tail->next; } }else{ msg_prev = msg_tail; msg_tail = msg_tail->next; } } // Add the client ID to the DB hash table here new_cih = _mosquitto_malloc(sizeof(struct _clientid_index_hash)); if(!new_cih){ _mosquitto_log_printf(NULL, MOSQ_LOG_ERR, "Error: Out of memory."); mqtt3_context_disconnect(db, context); rc = MOSQ_ERR_NOMEM; goto handle_connect_error; } new_cih->id = context->id; new_cih->db_context_index = context->db_index; HASH_ADD_KEYPTR(hh, db->clientid_index_hash, context->id, strlen(context->id), new_cih); #ifdef WITH_PERSISTENCE if(!clean_session){ db->persistence_changes++; } #endif /* Associate user with its ACL, assuming we have ACLs loaded. */ if(db->acl_list){ acl_tail = db->acl_list; while(acl_tail){ if(context->username){ if(acl_tail->username && !strcmp(context->username, acl_tail->username)){ context->acl_list = acl_tail; break; } }else{ if(acl_tail->username == NULL){ context->acl_list = acl_tail; break; } } acl_tail = acl_tail->next; } }else{ context->acl_list = NULL; } if(will_struct){ if(mosquitto_acl_check(db, context, will_topic, MOSQ_ACL_WRITE) != MOSQ_ERR_SUCCESS){ _mosquitto_send_connack(context, CONNACK_REFUSED_NOT_AUTHORIZED); mqtt3_context_disconnect(db, context); rc = MOSQ_ERR_SUCCESS; goto handle_connect_error; } context->will = will_struct; context->will->topic = will_topic; if(will_payload){ context->will->payload = will_payload; context->will->payloadlen = will_payloadlen; }else{ context->will->payload = NULL; context->will->payloadlen = 0; } context->will->qos = will_qos; context->will->retain = will_retain; } if(db->config->connection_messages == true){ if(context->is_bridge){ if(context->username){ _mosquitto_log_printf(NULL, MOSQ_LOG_NOTICE, "New bridge connected from %s as %s (c%d, k%d, u%s).", context->address, context->id, context->clean_session, context->keepalive, context->username); }else{ _mosquitto_log_printf(NULL, MOSQ_LOG_NOTICE, "New bridge connected from %s as %s (c%d, k%d).", context->address, context->id, context->clean_session, context->keepalive); } }else{ if(context->username){ _mosquitto_log_printf(NULL, MOSQ_LOG_NOTICE, "New client connected from %s as %s (c%d, k%d, u%s).", context->address, context->id, context->clean_session, context->keepalive, context->username); }else{ _mosquitto_log_printf(NULL, MOSQ_LOG_NOTICE, "New client connected from %s as %s (c%d, k%d).", context->address, context->id, context->clean_session, context->keepalive); } } } context->state = mosq_cs_connected; return _mosquitto_send_connack(context, CONNACK_ACCEPTED); handle_connect_error: if(client_id) _mosquitto_free(client_id); if(username) _mosquitto_free(username); if(password) _mosquitto_free(password); if(will_payload) _mosquitto_free(will_payload); if(will_topic) _mosquitto_free(will_topic); if(will_struct) _mosquitto_free(will_struct); return rc; } int mqtt3_handle_disconnect(struct mosquitto_db *db, struct mosquitto *context) { if(!context){ return MOSQ_ERR_INVAL; } if(context->in_packet.remaining_length != 0){ return MOSQ_ERR_PROTOCOL; } _mosquitto_log_printf(NULL, MOSQ_LOG_DEBUG, "Received DISCONNECT from %s", context->id); if(context->protocol == mosq_p_mqtt311){ if((context->in_packet.command&0x0F) != 0x00){ mqtt3_context_disconnect(db, context); return MOSQ_ERR_PROTOCOL; } } context->state = mosq_cs_disconnecting; mqtt3_context_disconnect(db, context); return MOSQ_ERR_SUCCESS; } int mqtt3_handle_subscribe(struct mosquitto_db *db, struct mosquitto *context) { int rc = 0; int rc2; uint16_t mid; char *sub; uint8_t qos; uint8_t *payload = NULL, *tmp_payload; uint32_t payloadlen = 0; int len; char *sub_mount; if(!context) return MOSQ_ERR_INVAL; _mosquitto_log_printf(NULL, MOSQ_LOG_DEBUG, "Received SUBSCRIBE from %s", context->id); /* FIXME - plenty of potential for memory leaks here */ if(context->protocol == mosq_p_mqtt311){ if((context->in_packet.command&0x0F) != 0x02){ return MOSQ_ERR_PROTOCOL; } } if(_mosquitto_read_uint16(&context->in_packet, &mid)) return 1; while(context->in_packet.pos < context->in_packet.remaining_length){ sub = NULL; if(_mosquitto_read_string(&context->in_packet, &sub)){ if(payload) _mosquitto_free(payload); return 1; } // printf("mqtt3_handle_subscribe topic:%s\n", sub); if(sub){ if(!strlen(sub)){ _mosquitto_log_printf(NULL, MOSQ_LOG_INFO, "Empty subscription string from %s, disconnecting.", context->address); _mosquitto_free(sub); if(payload) _mosquitto_free(payload); return 1; } if(_mosquitto_topic_wildcard_pos_check(sub)){ _mosquitto_log_printf(NULL, MOSQ_LOG_INFO, "Invalid subscription string from %s, disconnecting.", context->address); _mosquitto_free(sub); if(payload) _mosquitto_free(payload); return 1; } if(_mosquitto_read_byte(&context->in_packet, &qos)){ _mosquitto_free(sub); if(payload) _mosquitto_free(payload); return 1; } if(qos > 2){ _mosquitto_log_printf(NULL, MOSQ_LOG_INFO, "Invalid QoS in subscription command from %s, disconnecting.", context->address); _mosquitto_free(sub); if(payload) _mosquitto_free(payload); return 1; } if(context->listener && context->listener->mount_point){ len = strlen(context->listener->mount_point) + strlen(sub) + 1; sub_mount = _mosquitto_calloc(len, sizeof(char)); if(!sub_mount){ _mosquitto_free(sub); if(payload) _mosquitto_free(payload); return MOSQ_ERR_NOMEM; } snprintf(sub_mount, len, "%s%s", context->listener->mount_point, sub); _mosquitto_free(sub); sub = sub_mount; } _mosquitto_log_printf(NULL, MOSQ_LOG_DEBUG, "\t%s (QoS %d)", sub, qos); if(context->protocol == mosq_p_mqtt311){ rc = mosquitto_acl_check(db, context, sub, MOSQ_ACL_READ); switch(rc){ case MOSQ_ERR_SUCCESS: break; case MOSQ_ERR_ACL_DENIED: qos = 0x80; break; default: _mosquitto_free(sub); return rc; } } if(qos != 0x80){ //mosquitto_acl_check如果检查没有问题 // printf("it's crutial to subclient%s\n", sub); rc2 = mqtt3_sub_add(db, context, sub, qos, &db->subs); if(rc2 == MOSQ_ERR_SUCCESS){ if(mqtt3_retain_queue(db, context, sub, qos)) rc = 1; //调用该函数保证刚上线的订阅端可以收到服务端储存的retain的消息 }else if(rc2 != -1){ rc = rc2; } _mosquitto_log_printf(NULL, MOSQ_LOG_SUBSCRIBE, "%s %d %s", context->id, qos, sub); } _mosquitto_free(sub); tmp_payload = _mosquitto_realloc(payload, payloadlen + 1); if(tmp_payload){ payload = tmp_payload; payload[payloadlen] = qos; payloadlen++; }else{ if(payload) _mosquitto_free(payload); return MOSQ_ERR_NOMEM; } } } if(context->protocol == mosq_p_mqtt311){ if(payloadlen == 0){ /* No subscriptions specified, protocol error. */ return MOSQ_ERR_PROTOCOL; } } if(_mosquitto_send_suback(context, mid, payloadlen, payload)) rc = 1; _mosquitto_free(payload); #ifdef WITH_PERSISTENCE db->persistence_changes++; #endif return rc; }