nuclear@0: #include <stdio.h>
nuclear@0: #include <stdlib.h>
nuclear@0: #include <string.h>
nuclear@0: #include <unistd.h>
nuclear@0: #include <sys/types.h>
nuclear@0: #include <sys/socket.h>
nuclear@0: #include <arpa/inet.h>
nuclear@0: #include <sys/time.h>
nuclear@0: #include <sys/select.h>
nuclear@0: 
nuclear@0: #define MAGIC		0x6d0f
nuclear@0: #define DISCOVER	1
nuclear@0: #define DREPLY		2
nuclear@0: 
nuclear@0: struct message {
nuclear@0: 	int magic;
nuclear@0: 	int type;
nuclear@0: 	char data[24];
nuclear@0: };
nuclear@0: 
nuclear@0: int discover(struct sockaddr_in *client_sa);
nuclear@0: 
nuclear@0: int opt_dport = 0x6d0f;	/* discover broadcast port */
nuclear@0: unsigned int opt_timeout = 5000;	/* 10 sec discovery timeout */
nuclear@0: 
nuclear@0: int main(int argc, char **argv)
nuclear@0: {
nuclear@0: }
nuclear@0: 
nuclear@0: int discover(struct sockaddr_in *client_sa)
nuclear@0: {
nuclear@0: 	int s, true = 1;
nuclear@0: 	struct sockaddr_in sa;
nuclear@0: 	unsigned int timeout = opt_timeout;
nuclear@0: 	struct message msg;
nuclear@0: 	struct timeval tv, tv_timeout;
nuclear@0: 
nuclear@0: 	if((s = socket(PF_INET, SOCK_DGRAM, 0)) == -1) {
nuclear@0: 		perror("failed to create discover datagram socket");
nuclear@0: 		return -1;
nuclear@0: 	}
nuclear@0: 	setsockopt(s, SOL_SOCKET, SO_BROADCAST, &true, sizeof true);
nuclear@0: 
nuclear@0: 	memset(&sa, 0, sizeof sa);
nuclear@0: 	sa.sin_family = AF_INET;
nuclear@0: 	sa.sin_port = htons(opt_dport);
nuclear@0: 	sa.sin_addr.s_addr = htonl(INADDR_ANY);
nuclear@0: 
nuclear@0: 	if(bind(s, (struct sockaddr*)&sa, sizeof sa) == -1) {
nuclear@0: 		perror("failed to bind datagram socket");
nuclear@0: 		close(s);
nuclear@0: 		return -1;
nuclear@0: 	}
nuclear@0: 
nuclear@0: 	do {
nuclear@0: 		msg.magic = MAGIC;
nuclear@0: 		msg.type = DISCOVER;
nuclear@0: 
nuclear@0: 		memset(&sa, 0, sizeof sa);
nuclear@0: 		sa.sin_family = AF_INET;
nuclear@0: 		sa.sin_port = htons(opt_dport);
nuclear@0: 		sa.sin_addr.s_addr = 0xffffffff;
nuclear@0: 
nuclear@0: 		if(sendto(s, &msg, sizeof msg, 0, (struct sockaddr*)&sa, sizeof sa) == -1) {
nuclear@0: 			perror("failed to send discovery bcast dgram");
nuclear@0: 			close(s);
nuclear@0: 			return -1;
nuclear@0: 		}
nuclear@0: 	} while(0);
nuclear@0: 
nuclear@0: 	close(s);
nuclear@0: 	return 0;
nuclear@0: }