1 #include <stdio.h> 2 #include <stdlib.h> 3 #include <unistd.h> 4 #include <sys/socket.h> 5 #include <netinet/in.h> 6 7 int main (int argc, char *argv[]) 8 { 9 int s, len, o, port = 6666; 10 char buf[512]; 11 struct sockaddr_in addr; 12 socklen_t addr_len = sizeof addr; 13 14 if (argc > 1) 15 port = atoi (argv[1]); 16 17 s = socket (PF_INET, SOCK_DGRAM, IPPROTO_UDP); 18 19 o = 1; 20 len = 4; 21 setsockopt (3, SOL_SOCKET, SO_REUSEADDR, &o, len); 22 23 addr.sin_family = AF_INET; 24 addr.sin_port = htons (port); 25 addr.sin_addr.s_addr = INADDR_ANY; /* receive broadcasts */ 26 27 bind (s, (struct sockaddr *) &addr, sizeof addr); 28 29 for (;;) { 30 len = recvfrom (s, buf, sizeof buf, 0, (struct sockaddr *) &addr, &addr_len); 31 if (len < 0) 32 break; 33 if (write (1, buf, len) != len) 34 fprintf(stderr, "WARNING: serial characters dropped\n"); 35 } 36 37 return 0; 38 } 39