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>
natc itself can't immediately fix the problem, but it can more correctly
error that return bad addresses.
Updates tailscale/corp#26968
Signed-off-by: James Tucker <james@tailscale.com>
These tunings reduced memory usage while the implementation was
struggling with earlier bugs, but will no longer be necessary after
those bugs are addressed.
Depends #14933
Depends #14934
Updates #9707
Updates #10408
Updates tailscale/corp#24483
Updates tailscale/corp#25169
Signed-off-by: James Tucker <james@tailscale.com>
It was moved in f57fa3cbc30e.
Updates tailscale/corp#22748
Change-Id: I19f965e6bded1d4c919310aa5b864f2de0cd6220
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Some natc instances have been observed with excessive memory growth,
dominant in gvisor buffers. It is likely that the connection buffers are
sticking around for too long due to the default long segment time, and
uptuned buffer size applied by default in wgengine/netstack. Apply
configurations in natc specifically which are a better match for the
natc use case, most notably a 5s maximum segment lifetime.
Updates tailscale/corp#25169
Signed-off-by: James Tucker <james@tailscale.com>
This adds a new prototype `cmd/natc` which can be used
to expose a services/domains to the tailnet.
It requires the user to specify a set of IPv4 prefixes
from the CGNAT range. It advertises these as normal subnet
routes. It listens for DNS on the first IP of the first range
provided to it.
When it gets a DNS query it allocates an IP for that domain
from the v4 range. Subsequent connections to the assigned IP
are then tcp proxied to the domain.
It is marked as a WIP prototype and requires the use of the
`TAILSCALE_USE_WIP_CODE` env var.
Updates tailscale/corp#20503
Signed-off-by: Maisem Ali <maisem@tailscale.com>
