On 5/31/23 20:11, Guillaume Nault wrote:
On Wed, May 24, 2023 at 02:17:09PM +0200, Mirsad Todorovac wrote:
Hi,
Hi Mirsad,
Hi Guillaume,
The very recent 6.4-rc3 kernel build with AlmaLinux 8.7 on LENOVO 10TX000VCR
desktop box fails one test:
[root@host net]# ./fcnal-test.sh
[...]
TEST: ping out, vrf device+address bind - ns-B loopback IPv6 [ OK ]
TEST: ping out, vrf device+address bind - ns-B IPv6 LLA [FAIL]
TEST: ping in - ns-A IPv6 [ OK ]
[...]
Tests passed: 887
Tests failed: 1
[root@host net]#
This test also fails on -net. The problem is specific to ping sockets
(same test passes with raw sockets). I believe this test has always
failed since fcnal-test.sh started using net.ipv4.ping_group_range
(commit e71b7f1f44d3 ("selftests: add ping test with ping_group_range
tuned")).
The executed command is:
ip netns exec ns-A ip vrf exec red /usr/bin/ping6 -c1 -w1 -I 2001:db8:3::1 fe80::a846:b5ff:fe4c:da4e%eth1
So ping6 is executed inside VRF 'red' and sets .sin6_scope_id to 'eth1'
(which is a slave device of VRF 'red'). Therefore, we have
sk->sk_bound_dev_if == 'red' and .sin6_scope_id == 'eth1'. This fails
because ping_v6_sendmsg() expects them to be equal:
static int ping_v6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
{
...
if (__ipv6_addr_needs_scope_id(ipv6_addr_type(daddr)))
oif = u->sin6_scope_id;
...
if ((__ipv6_addr_needs_scope_id(addr_type) && !oif) ||
(addr_type & IPV6_ADDR_MAPPED) ||
(oif && sk->sk_bound_dev_if && oif != sk->sk_bound_dev_if)) <-- oif='eth1', but ->sk_bound_dev_if='red'
return -EINVAL;
...
}
Thank you for your thorough investigation. It helps a great deal to
understand the issue.
I am really not that into the network stack, though I can always smuggle
the work on the network stack as a work on high-bandwidth multimedia
and do it in day hours.
Probably I need to catch up with the network stack homework.
I believe this condition should be relaxed to allow the case where
->sk_bound_dev_if is oif's master device (and maybe there are other
VRF cases to also consider).
I have looked into the code, but currently my knowledge of the code is
not sufficient for the intervention.
Thank you,
Mirsad
