sendtun(const char *data, size_t len)
{
// printf("Sent len %d, csum %d\n", len, checksum(data, len));
write(tfd, data, len);
size_t w = write(tfd, data, len);
if (w < len) {
fprintf(stderr, "packet was descrutively fragmented! (len=%zd, "
"wrote=%zd)\n",
len, w);
}
void
