/* Test setting SO_BROADCAST, connecting to the broadcast address port 1 and printing the remote address. */ #include "udp.h" int main(void) { int fd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP); if ( fd < 0 ) err(1, "socket"); int enable = 1; if ( setsockopt(fd, SOL_SOCKET, SO_BROADCAST, &enable, sizeof(enable)) < 0 ) err(1, "setsockopt: SO_BROADCAST"); struct sockaddr_in sin; memset(&sin, 0, sizeof(sin)); sin.sin_family = AF_INET; sin.sin_addr.s_addr = htobe32(INADDR_BROADCAST); sin.sin_port = htobe16(1); if ( connect(fd, (const struct sockaddr*) &sin, sizeof(sin)) < 0 ) err(1, "connect"); struct sockaddr_in local; socklen_t locallen = sizeof(local); if ( getpeername(fd, (struct sockaddr*) &local, &locallen) < 0 ) err(1, "getpeername"); char host[INET_ADDRSTRLEN + 1]; char port[5 + 1]; getnameinfo((const struct sockaddr*) &local, locallen, host, sizeof(host), port, sizeof(port), NI_NUMERICHOST | NI_NUMERICSERV); printf("%s:%s\n", host, port); return 0; }