netlink: Fix iterations over nexthop objects

Somewhat confusingly, RTNH_NEXT(), as defined by <linux/rtnetlink.h>,
doesn't take an attribute length parameter like RTA_NEXT() does, and
I just modelled loops over nexthops after RTA loops, forgetting to
decrease the remaining length we pass to RTNH_OK().

In practice, this didn't cause issue in any of the combinations I
checked, at least without the next patch.

We seem to be the only user of RTNH_OK(): even iproute2 has an
open-coded version of it in print_rta_multipath() (ip/iproute.c).

Introduce RTNH_NEXT_AND_DEC(), similar to RTA_NEXT(), and use it.

Fixes: 6c7623d07bbd ("netlink: Add support to fetch default gateway from multipath routes")
Fixes: f4e38b5cd232 ("netlink: Adjust interface index inside copied nexthop objects too")
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

0 files changed, 0 insertions, 0 deletions