1 #include <stdlib.h> 2 #include <unistd.h> 3 #include <sys/socket.h> 4 #include <linux/in.h> 5 6 int main (int argc, char *argv[]) 7 { 8 int s, len, o, port = 6666; 9 char buf[512]; 10 struct sockaddr_in addr; 11 socklen_t addr_len = sizeof addr; 12 13 if (argc > 1) 14 port = atoi (argv[1]); 15 16 s = socket (PF_INET, SOCK_DGRAM, IPPROTO_UDP); 17 18 o = 1; 19 len = 4; 20 setsockopt (3, SOL_SOCKET, SO_REUSEADDR, &o, len); 21 22 addr.sin_family = AF_INET; 23 addr.sin_port = htons (port); 24 addr.sin_addr.s_addr = INADDR_ANY; /* receive broadcasts */ 25 26 bind (s, (struct sockaddr *) &addr, sizeof addr); 27 28 for (;;) { 29 len = recvfrom (s, buf, sizeof buf, 0, (struct sockaddr *) &addr, &addr_len); 30 if (len < 0) 31 break; 32 write (1, buf, len); 33 } 34 35 return 0; 36 } 37