Source IP selection or multi-home or multi-interface issue - solved with source-based route - was: Re: Wireguard source ip selection issue with multi interfaces

[曹煜]

Hi,
Actually, I've hacked the wireguard source code by myself months ago,
and it's working as expected on openwrt with mwan3.
See details and the last hack patch on my github issue:
https://github.com/openwrt/packages/issues/9538
As I said on the issue, the problem is wireguard always reset the
incoming ip and ipmark, and then select the source ip from main
routing table.

Janne Johansson <icepic.dz at gmail.com> 于2022年10月21日周五 21:27写道：
>
> > "How should wireguard know which IP is the correct source IP address?"
> >
> > I digged into the source code but couldn't find the part where the source-IP is selected for outgoing connections (like a simple ping).
> > I am not a developer but would like to try to understand it. Could someone give me a pointer?
>
> I think it is left to the OS and it's tcp stack to pick the ip (and
> interface) based on the UDP destination ip and the current routing
> table when sending udp packets.
>
> --
> May the most significant bit of your life be positive.