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