Correct loopback route for aliases IP addresses

[zlei]

Summary

A loopback route is required only when the logical interface is not a loopback.

PR: 256681

Test Plan

Create loopback, tun and tap clones, with IP address and IP aliases, verify the route table is expected.

[zlei]

sys/netinet/in.c

780

TODO: Need revision to reflect the change.

[zlei]

sys/netinet/in.c

938

Not sure if it is useful to routing daemons.

[donner]

I'm surprised. There was a discussion about not redirecting /32 on interfaces to loopback. So we see the consequence.

[kp]

I believe this bug is also related: #255685

[zlei]

In D30811#692900, @donner wrote:

I'm surprised. There was a discussion about not redirecting /32 on interfaces to loopback. So we see the consequence.

Can you please share the discussion? Thanks!

[zlei]

I think I hit the issue that the useloopback was trying to resolve.

[1]: https://cgit.freebsd.org/src/commit/sys/?h=stable/8&id=df813b7ea23bd5d41359f0c7bf8b69ee89b7e1c6
[2]: https://cgit.freebsd.org/src/commit/sys?h=stable/11&id=b1b9dcae46803ae79255a9994584cb03d2a77048

[donner]

In D30811#693218, @zlei.huang_gmail.com wrote:

Can you please share the discussion? Thanks!

Unfortunately not. The mailing list archive is not accessible to me.

[zlei]

Abandoned since it works as intended.