/* Connect to loopback address port 65535 and then test sendto with another address (loopback address port 65534). */ #include "udp.h" int main(void) { int fd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP); if ( fd < 0 ) err(1, "socket"); struct sockaddr_in sin; memset(&sin, 0, sizeof(sin)); sin.sin_family = AF_INET; sin.sin_addr.s_addr = htobe32(INADDR_LOOPBACK); sin.sin_port = htobe16(65535); if ( connect(fd, (const struct sockaddr*) &sin, sizeof(sin)) < 0 ) err(1, "connect"); struct sockaddr_in cos; memset(&cos, 0, sizeof(cos)); cos.sin_family = AF_INET; cos.sin_addr.s_addr = htobe32(INADDR_LOOPBACK); cos.sin_port = htobe16(65534); char x = 'x'; if ( sendto(fd, &x, sizeof(x), 0, (const struct sockaddr*) &cos, sizeof(cos)) < 0 ) err(1, "sendto"); return 0; }