receive_packet
ssize_t receive_packet(struct interface_info *, unsigned char *, size_t,
if ((result = receive_packet(ip, u.packbuf, sizeof u,
ssize_t receive_packet(struct interface_info *, unsigned char *, size_t,
if ((result = receive_packet(ip, u.packbuf, sizeof(u), &pc)) == -1) {
ssize_t receive_packet(struct interface_info *, unsigned char *, size_t,
if ((result = receive_packet(ip, buf, sizeof(buf), &pc)) == -1) {