void setup() {
// Set the port whis to use for contactign us back
Udp.begin(8888);
// Sedn the message to the server
if (Udp.sendPacket(buffer, 39, remoteIP, port) < 0) {
Particle.publish("Error");
}
}
void loop() {
if (WiFi.ready()) {
if (firstTimeReady) {
firstTimeReady = false;
// First time we get WiFi.ready(), initialize the UDP listener. This happens
// every time we reconnect to WiFi.
mcastUdp.begin(MCAST_PORT);
}
if (!haveServerAddr && millis() - serverAddrLastCheck >= SERVER_ADDR_CHECK_RETRY_MS) {
serverAddrLastCheck = millis();
// If we don't have a server IP address, request it periodically (every 20 seconds)
Serial.printlnf("requesting server address at %s:%d", mcastAddr.toString().c_str(), MCAST_PORT);
strcpy(udpBuffer, "\n");
mcastUdp.sendPacket(udpBuffer, strlen(udpBuffer), mcastAddr, MCAST_PORT);
}
int count = mcastUdp.receivePacket(udpBuffer, UDP_BUFFER_SIZE - 1);
if (count > 0) {
udpBuffer[count] = 0;
// Handle a received UDP packet from the server with the IP address and port of the server
int addr[4], port;
if (sscanf(udpBuffer, "%u.%u.%u.%u:%u", &addr[0], &addr[1], &addr[2], &addr[3], &port) == 5) {
serverAddr = IPAddress(addr[0], addr[1], addr[2], addr[3]);
serverPort = port;
haveServerAddr = true;
Serial.printlnf("serverAddr=%s port=%d", serverAddr.toString().c_str(), serverPort);
}
}
}
else {
// If WiFi disconnects, we need to reestablish listeners next time
firstTimeReady = true;
}
}
/* executes continuously after setup() runs */
void loop() {
static system_tick_t last = 0;
ssize_t s = udp.receivePacket(buf, sizeof(buf));
if (s > 0) {
char tmp[IP_ADDR_STRLEN_MAX] = {};
auto ip = udp.remoteIP();
Log.trace("Received %d bytes from %s#%u", s,
inet_inet_ntop(AF_INET6, ip.raw().ipv6, tmp, sizeof(tmp)), udp.remotePort());
}
if ((millis() - last) >= PERIOD) {
size_t len = random(1, sizeof(buf));
rng.gen((char*)buf, len);
auto r = udp.sendPacket(buf, len, mcastAddr, PORT);
Log.trace("Sent %u bytes to %s#%u : %d %d", len, MULTICAST_ADDR, PORT, r, errno);
last = millis();
if (r < 0) {
openSocket();
}
}
}