must_write
must_write(socks[0], &ret, sizeof(int));
must_write(socks[0], &ret, sizeof(int));
must_write(priv_fd, &cmd, sizeof(int));
must_write(priv_fd, &snaplen, sizeof(int));
must_write(priv_fd, &cmd, sizeof(int));
must_write(priv_fd, &cmd, sizeof(int));
static void must_write(int, void *, size_t);