ESP8266 Community Forum

- Sun May 19, 2019 3:05 pm #82387 Hi,

When I create a second UDP connection with:

espconn_create(struct espconn *espconn)

Both connecions with all the remote and local data (ports and IPs) different, the data of the first connection is overwritten by the second one.

Has anybody experience this?

- Mon May 20, 2019 4:36 am #82390 Can you put up a code snippet?

You are allocating two separate espconn structures, aren't you? Dumb question I know but best to ask the obvious questions first

- Mon May 20, 2019 10:20 am #82397 Here you go:

CREATION OF CONNECTOR 1

Code: Select all     struct espconn udp_mdns_connector;

    //setup UDP the connector
    os_memset(&udp_mdns_connector, 0, sizeof(udp_mdns_connector));
    udp_mdns_connector.type = ESPCONN_UDP;
    udp_mdns_connector.state = ESPCONN_NONE;
    udp_mdns_connector.proto.udp = &udp_con;

    os_memset(&udp_con, 0, sizeof(udp_con));

    udp_con.local_ip[0] = ip4_addr1(&stationIp.ip);
    udp_con.local_ip[1] = ip4_addr2(&stationIp.ip);
    udp_con.local_ip[2] = ip4_addr3(&stationIp.ip);
    udp_con.local_ip[3] = ip4_addr4(&stationIp.ip);

    /*set mdns multicast ip addr*/
    os_memcpy(udp_con.remote_ip, mdns_multicastIp, sizeof(mdns_multicastIp));

    udp_con.local_port = MDNS_PORT;
    udp_con.remote_port = MDNS_PORT;

    /* set data callback for when data has been sent/received */
    espconn_regist_recvcb(&udp_mdns_connector, &_mdns_response_received);
    espconn_regist_sentcb(&udp_mdns_connector, &_mdns_dataSent);

    /* create udp connector */
    err = espconn_create(&udp_mdns_connector);


CREATION OF CONNECTOR 2:

Code: Select all    struct espconn connector;
    //Connect and send some data
    os_memset( &connector, 0, sizeof(connector));
    connector.type = ESPCONN_UDP;
    connector.state = ESPCONN_NONE;
    connector.proto.udp = &udp_con;
   
    os_memset( &udp_con, 0, sizeof(udp_con));
    wifi_get_ip_info( STATION_IF, &stationIp );
   
    udp_con.local_ip[0] = ip4_addr1(&stationIp.ip);
    udp_con.local_ip[1] = ip4_addr2(&stationIp.ip);
    udp_con.local_ip[2] = ip4_addr3(&stationIp.ip);
    udp_con.local_ip[3] = ip4_addr4(&stationIp.ip);
    udp_con.local_port = 8181;

    udp_con.remote_port = rdp_serverPort;
    os_memcpy ( udp_con.remote_ip, rdp_serverIp, 4 );

    // set some data callbacks
    espconn_regist_recvcb( &connector, &rdp_dataReceived );
    espconn_regist_sentcb( &connector, &rdp_dataSent );
   
    err = espconn_create ( &connector );


Last edited by maverickchongo on Tue May 21, 2019 5:51 am, edited 1 time in total.

- Mon May 20, 2019 6:38 pm #82403 Are you setting the connection type somewhere? Something like

Code: Select alludp_con.type = ESPCONN_UDP;

Also UDP is different to TCP - you need to set the remote ip and port before every single send call, otherwise it remembers the last info. See:
http://controllingtheinter.net/2018/06/04/resolving-udp-and-igmp-issue-with-esp8266/

"If it is a UDP transmission, please set espconn->proto.udp->remote_ip and remote_port before every calling of espconn_send."