This document provides a sample configuration on how to configure the digital inputs on the router to mirror the digital relay outputs on a remote router.

PORT the UDP port of the remote router
REMOTE the remote router IP address
FREQ the frequency in seconds to send updates to the remote router

/* 
 * Copyright (C) 2019 AVVERO
 */

PORT = 6666;
REMOTE = "172.30.6.110";
FREQ = 1;

sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
if (sock < 0) {
    nb_syslog("Unable to open socket\n");
    exit(1);
}

ret = bind(sock, PORT, "");
if(ret == -1) {
    nb_syslog("Unable to bind to port: %d\n", PORT);
    close(sock);
    exit(1);
}

nb_syslog("Sending messages on port %d\n", PORT);

for(;;)
{
    sleep(FREQ);
    MSG = sprintf("in1=%d in2=%d out1=%d out2=%d",
         nb_dio_get("in1"),
         nb_dio_get("in2"),
         nb_dio_get("out1"),
         nb_dio_get("out2"));

    if (sendto(sock, MSG, REMOTE, PORT) != strlen(MSG))
        nb_syslog("ERROR: UDP GPIO message failed");	
}

PORT the UDP port of the remote router

  /* 
   * Copyright (C) 2019 AVVERO
   */

  PORT = 6666;

  sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
  if (sock < 0) {
      nb_syslog("Unable to open socket\n");
      exit(1);
  }

  ret = bind(sock, PORT, "");
  if(ret == -1) {
      nb_syslog("Unable to bind to port: %d\n", PORT);
      close(sock);
      exit(1);
  }

  nb_syslog("Listening for messages on port %d\n", PORT);

  while (1) {
      msg = recvfrom(sock);
      if (msg != "") {
    ret = (int) strstr(msg, "in1");
    state  = (int) substr(msg, (ret+4), 1);
    cin1 = nb_dio_get("out1");
      if (state != cin1) {
              nb_dio_set("out1", state);
              nb_syslog("Digital Relay = %s",state);
    }
    ret = (int) strstr(msg, "in2");
    state  = (int) substr(msg, (ret+4), 1);
      cin2 = nb_dio_get("out2");
      if (state != cin2) {
              nb_dio_set("out2", state);
              nb_syslog("Digital Relay = %s",state);
      }
      }
}
  close(sock);
  exit(0);