mbed_example / Mbed OS mbed-os-example-udp-sockets

UDP Socket application to read current time from network.

main.cpp@0:cf516d904427, 2017-10-23 (annotated)

Committer:
deepikabhavnani
Date:
Mon Oct 23 21:26:36 2017 +0000
Revision:
0:cf516d904427
UDP Socket example - Initial commit

Who changed what in which revision?

UserRevisionLine numberNew contents of line
deepikabhavnani 0:cf516d904427 1 #include "mbed.h"
deepikabhavnani 0:cf516d904427 2 #include "EthernetInterface.h"
deepikabhavnani 0:cf516d904427 3
deepikabhavnani 0:cf516d904427 4 // Network interface
deepikabhavnani 0:cf516d904427 5 EthernetInterface net;
deepikabhavnani 0:cf516d904427 6
deepikabhavnani 0:cf516d904427 7 // Time protocol implementation : Address: time.nist.gov UDPPort: 37
deepikabhavnani 0:cf516d904427 8
deepikabhavnani 0:cf516d904427 9 typedef struct {
deepikabhavnani 0:cf516d904427 10 uint32_t secs; // Transmit Time-stamp seconds.
deepikabhavnani 0:cf516d904427 11 }ntp_packet;
deepikabhavnani 0:cf516d904427 12
deepikabhavnani 0:cf516d904427 13 int main() {
deepikabhavnani 0:cf516d904427 14 // Bring up the ethernet interface
deepikabhavnani 0:cf516d904427 15 printf("UDP Socket example\n");
deepikabhavnani 0:cf516d904427 16 if(0 != net.connect()) {
deepikabhavnani 0:cf516d904427 17 printf("Error connecting\n");
deepikabhavnani 0:cf516d904427 18 return -1;
deepikabhavnani 0:cf516d904427 19 }
deepikabhavnani 0:cf516d904427 20
deepikabhavnani 0:cf516d904427 21 // Show the network address
deepikabhavnani 0:cf516d904427 22 const char *ip = net.get_ip_address();
deepikabhavnani 0:cf516d904427 23 printf("IP address is: %s\n", ip ? ip : "No IP");
deepikabhavnani 0:cf516d904427 24
deepikabhavnani 0:cf516d904427 25 UDPSocket sock(&net);
deepikabhavnani 0:cf516d904427 26 SocketAddress sockAddr;
deepikabhavnani 0:cf516d904427 27
deepikabhavnani 0:cf516d904427 28 char out_buffer[] = "time";
deepikabhavnani 0:cf516d904427 29 if(0 > sock.sendto("time.nist.gov", 37, out_buffer, sizeof(out_buffer))) {
deepikabhavnani 0:cf516d904427 30 printf("Error sending data\n");
deepikabhavnani 0:cf516d904427 31 return -1;
deepikabhavnani 0:cf516d904427 32 }
deepikabhavnani 0:cf516d904427 33
deepikabhavnani 0:cf516d904427 34 ntp_packet in_data;
deepikabhavnani 0:cf516d904427 35 int n = sock.recvfrom(&sockAddr, &in_data, sizeof(ntp_packet));
deepikabhavnani 0:cf516d904427 36 in_data.secs = ntohl( in_data.secs ) - 2208988800; // 1900-1970
deepikabhavnani 0:cf516d904427 37 printf("Time Received %lu seconds since 1/01/1900 00:00 GMT\n",
deepikabhavnani 0:cf516d904427 38 (uint32_t)in_data.secs);
deepikabhavnani 0:cf516d904427 39 printf("Time = %s", ctime(( const time_t* )&in_data.secs));
deepikabhavnani 0:cf516d904427 40
deepikabhavnani 0:cf516d904427 41 printf("Time Server Address: %s Port: %d\n\r",
deepikabhavnani 0:cf516d904427 42 sockAddr.get_ip_address(), sockAddr.get_port());
deepikabhavnani 0:cf516d904427 43
deepikabhavnani 0:cf516d904427 44 // Close the socket and bring down the network interface
deepikabhavnani 0:cf516d904427 45 sock.close();
deepikabhavnani 0:cf516d904427 46 net.disconnect();
deepikabhavnani 0:cf516d904427 47 return 0;
deepikabhavnani 0:cf516d904427 48 }