Source IP incorrect on multi homed systems

[Luiz Angelo Daros de Luca]

Yes, wg is not a request/response protocol. But it does have some
state. Can't wireguard remember the last local address that each peer
sent traffic? It is just like the tracking already in use for peer ip
address. If there is an "last address" it would be nice if we could
hint the kernel to use that as the source address, with a fallback to
the current behavior if the address is not available. It might solve a
couple of problems. I just don't know if it is possible to hint the
source address without enforcing it. It not, wg would have to deal
with cases when the address is gone.

Regards,

Luiz