Avoid the unbounded runtime during random allocation, if random
allocation fails after a first pass at random through the provided
ranges, pick the next free address by walking through the allocated set.
The new ipx utilities provide a bitset based allocation pool, good for
small to moderate ranges of IPv4 addresses as used in natc.
Updates #15367
Signed-off-by: James Tucker <james@tailscale.com>
This is a very dumb fix as it has an unbounded worst case runtime. IP
allocation needs to be done in a more sane way in a follow-up.
Updates #15367
Signed-off-by: James Tucker <james@tailscale.com>
These tests aren't perfect, nor is this complete coverage, but this is a
set of coverage that is at least stable.
Updates #15367
Signed-off-by: James Tucker <james@tailscale.com>