Host routes can include a preferred source address
(RTA_PREFSRC), which
must be one of the host's addresses. However when using pasta with -a the
namespace might be given a different address, not on the host. This seems
to occur pretty routinely depending on the network configuration systems
in place on the host.
With --config-net we will try to copy host routes to the namespace. If
one of those includes an RTA_PREFSRC, but the namespace doesn't have the
host address, this will fail with -EINVAL, causing pasta to fail.
Fix this by stripping off RTA_PREFSRC attributes from routes as we copy
them to the namespace. This is by no means infallible, bit it should at
least handle common cases for the time being.
Link:
https://bugs.passt.top/show_bug.cgi?id=71
Link:
https://github.com/containers/podman/pull/19699#issuecomment-1688769287
Signed-off-by: David Gibson <david(a)gibson.dropbear.id.au>