We have a filter in tailscaled itself now, which is more robust
against weird network topologies (such as the one Docker creates).
Signed-off-by: David Anderson <danderson@tailscale.com>
Instead of retrieving the list of chains, or the list of rules in a
chain, just try deleting the ones we don't want and then adding the
ones we do want. An error in flushing/deleting still means the rule
doesn't exist anymore, so there was no need to check for it first.
This avoids the need to parse iptables output, which avoids the need to
ever call iptables -S, which fixes#403, among other things. It's also
much more future proof in case the iptables command line changes.
Unfortunately the iptables go module doesn't properly pass the iptables
command exit code back up when doing .Delete(), so we can't correctly
check the exit code there. (exit code 1 really means the rule didn't
exist, rather than some other weird problem).
Signed-off-by: Avery Pennarun <apenwarr@tailscale.com>
This removes the use of suppress_ifgroup and fwmark "x/y" notation,
which are, among other things, not available in busybox and centos6.
We also use the return codes from the 'ip' program instead of trying to
parse its output.
I also had to remove the previous hack that routed all of 100.64.0.0/10
by default, because that would add the /10 route into the 'main' route
table instead of the new table 88, which is no good. It was a terrible
hack anyway; if we wanted to capture that route, we should have
captured it explicitly as a subnet route, not as part of the addr. Note
however that this change affects all platforms, so hopefully there
won't be any surprises elsewhere.
Fixes#405
Updates #320, #144
Signed-off-by: Avery Pennarun <apenwarr@tailscale.com>
The comment module is compiled out on several embedded systems (and
also gentoo, because netfilter can't go brrrr with comments holding it
back). Attempting to use comments results in a confusing error, and a
non-functional firewall.
Additionally, make the legacy rule cleanup non-fatal, because we *do*
have to probe for the existence of these -m comment rules, and doing
so will error out on these systems.
Signed-off-by: David Anderson <danderson@tailscale.com>
