Re: [PATCH] netlink: Fix nl_route_dup by 3-step processing

[Stefano Brivio <sbrivio@redhat.com>]

On Sat,  7 Nov 2026 12:46:21 +0100
Martin Schitter <ms+git@mur.at> wrote:

> Eliminate the route entries capacity limitations of nl_route_dup
> by copying them to the destination namespace in three successive
> steps to bypass dependency issues. This approach is inspired by
> the code design used in the restore subcommand of iproute2.
>
> [...]

Sorry, I'm not sure why, but this breaks Podman tests on my setup,
which has (for IPv4) a single /27 address, and a default, single route
via the gateway.  If I do:

  ./pasta -a 192.0.2.1

I get EINVAL on the second route insertion in nl_route_dup().  If the
address is configured as /32 it works, if it's anything else (/31 or
shorter mask), it doesn't.

Isolated one-line reproducer (which should be independent from the
network setup):

  $ ./pasta -Ix -- sh -c 'ip l set dev x up && ip a a 198.50.100.2/31 dev x && ./pasta -4 --config-net -a 192.0.2.1'
  Couldn't set IPv4 route(s) in guest: Invalid argument

I didn't debug further than that.

-- 
Stefano