findbuddy.cpp

00001 #include "SimpleSocket.h"
00002 
00003 void findbuddy()
00004 {
00005     int myIP[4];
00006     sscanf(EthernetInterface::getIPAddress(), "%d.%d.%d.%d", myIP, myIP + 1, myIP + 2, myIP + 3);
00007 
00008     DatagramSocket datagram(7777);
00009 
00010     char buddy[32] = {};
00011     int port;
00012     for (int i = myIP[3] + 1;; i = (i - myIP[3] + 260) % 10 + myIP[3] + 1) {
00013         sprintf(buddy, "%d.%d.%d.%d", myIP[0], myIP[1], myIP[2], i);
00014         printf("sending message to %s\n", buddy);
00015         datagram.printf("Hello World\n");
00016 
00017         datagram.send(buddy, 7777);
00018         // this will not reach target during the first round,
00019         // and in order to receive successfully,
00020         // timeout must be at least 4 seconds (default = 5.0 seconds)
00021         datagram.setTimeout(4.0);
00022         if (datagram.receive(buddy, &port) > 0) {
00023             char buf[80] = {};
00024             int len = datagram.read(buf, sizeof(buf) - 1);
00025             printf("received from %s: %s", buddy, buf);
00026             break;
00027         }
00028     }
00029 
00030     for (int i = 0; i < 2; i++) {
00031         datagram.printf("There you are!\n");
00032         datagram.send(buddy, 7777);
00033 
00034         if (datagram.receive() > 0) {
00035             char buf[80] = {};
00036             int len = datagram.read(buf, sizeof(buf) - 1);
00037             printf("received: %s", buf);
00038         }
00039     }
00040 }