IP options were not being compared prior to coalescing. They are not commonly used. Disqualification due to nonzero options is in line with the kernel. Reviewed-by: Denton Gentry <dgentry@tailscale.com> Signed-off-by: Jordan Whited <jordan@tailscale.com> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>