When we enable/disable exit mode on this restarts the unbound DNS
responder with the DNS trampoline (or restores upstream, when disabling)
to properly route DNS requests through the tunnel (because libunbound's
direct requests don't get tunneled because unbound is inside the network
extension).
The reason the dns fix on android didn't work is that the DnsInterceptor
had a reversed to/from argument order for its
`SendServerMessageBufferTo` overload, and so android/mac needed the
to/from to be reversed so that the second reverse cancelled out the
first one.
Upon review, the DnsInterceptor order (to, from) is more intuitive than
the base order (from, to), so this reapplies the dns fix and swaps
everything *except* DnsInterceptor to match the (to, from) argument
order.
This reverts commit dace0224ec.
This reportedly didn't fix things on Android, and most definitely breaks
macOS (with this we get a bunch of errors about expecting inbound when
we have outbound).
* make it so that we don't set up unbound resolver when we have no resolvers provided by config
* clean up dns codepath and make it use llarp::SockAddr instead of llarp::IpAddress
* add option to persist address mappings between restarts using [network]:persist-addrmap-file
* make it work
* only persist address map for inbound convos
* turn persisting address map on by default
* dont load addrmap file if it has been modified last over a minute ago to prevent foot cannons fired from loading a really old version of it
so it doesn't time out and get into a state that's totally screwed.
add virtual function service::Endpont::DefaultPathAlignmentTimeout() to get the timeout for path alignment
and use it for resetablishing outbound sessions
adds [network] section parameter called path-alignment-timeout that allows configring the timeout
for optional name lookup + introset lookup + aligned path build, used by tun endpoint dns, provided
as milliseconds.
Wires up systemd support to configure DNS on startup and when
enabling/disabling exit mode.
On startup (and when turning off an exit) we tell systemd-resolved to
direct .loki and .snode lookups to lokinet (leaving other DNS traffic
alone).
On exit enabling, we reconfigure it to resolve "." (i.e. the root DNS
domain) so that all lookups come into it.
