* [client] Reuse one wgctrl client in the kernel configurer
The kernel configurer opened a new wgctrl client for every request,
paying a socket open, a generic netlink family lookup and a close on
each peer update. With 10000 peers a single update dropped from about
37us to 10us per call once the client is kept open.
The configurer now opens the client lazily on the first request and
keeps it. A failed request drops the client so the next one opens a
fresh socket: a reply cut short mid-dump leaves stale messages in the
netlink buffer, and reusing that socket would fail every later request
on a sequence mismatch. The failed request is not retried.
Close releases the client and rejects later requests instead of
reopening a socket nobody would close. The kernel device never closed
its configurer, so it now keeps it and closes it on teardown.
- Move `util/grpc` and `util/net` to `client` so `internal` packages can be accessed
- Add methods to return the next best interface after the NetBird interface.
- Use `IP_UNICAST_IF` sock opt to force the outgoing interface for the NetBird `net.Dialer` and `net.ListenerConfig` to avoid routing loops. The interface is picked by the new route lookup method.
- Some refactoring to avoid import cycles
- Old behavior is available through `NB_USE_LEGACY_ROUTING=true` env var
Deduplicate STUN package sending.
Originally, because every peer shared the same UDP address, the library could not distinguish which STUN message was associated with which candidate. As a result, the Pion library responded from all candidates for every STUN message.
Zoltan Papp