Messages in this thread Patch in this message |  | | Subject | Re: [REGRESSION] connection timeout with routes to VRF | From | Jan Luebbe <> | Date | Wed, 06 Jul 2022 20:49:27 +0200 |
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On Sun, 2022-06-26 at 21:06 +0100, Mike Manning wrote: ... > Andy Roulin suggested the same fix to the same problem a few weeks back. > Let's do it along with a test case in fcnl-test.sh which covers all of > these vrf permutations. > Reverting 3c82a21f4320 would remove isolation between the default and other VRFs needed when no VRF route leaking has been configured between these: there may be unintended leaking of packets arriving on a device enslaved to an l3mdev due to the potential match on an unbound socket.
Thanks for the explanation.
VRF route leaking requires routes to be present for both ingress and egress VRFs, the testcase shown only has a route from default to red VRF. The implicit return path from red to default VRF due to match on unbound socket is no longer present.
If there is a better configuration that makes this work in the general case without a change to the kernel, we'd be happy as well.
In our full setup, the outbound TCP connection (from the default VRF) gets a local IP from the interface enslaved to the VRF. Before 3c82a21f4320, this would simply work.
How would the return path route from the red VRF to the default VRF look in that case?
Match on unbound socket in all VRFs and not only in the default VRF should be possible by setting this option (see https://www.kernel.org/doc/Documentation/networking/vrf.txt):
Do you mean unbound as in listening socket not bound to an IP with bind()? Or as in a socket in the default VRF?
sysctl net.ipv4.tcp_l3mdev_accept=1
The sysctl docs sound like this should only apply to listening sockets. In this case, we have an unconnected outbound socket.
However, for this to work a change similar to the following is needed (I have shown the change to the macro for consistency with above, it is now an inline fn):
I can also test on master and only used the macro form only because I wasn't completely sure how to translate it to the inline function form.
--- include/net/inet_hashtables.h | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-)
--- a/include/net/inet_hashtables.h +++ b/include/net/inet_hashtables.h @@ -300,9 +300,8 @@ #define INET_MATCH(__sk, __net, __cookie, __saddr, __daddr, __ports, __dif, __sdif) \ (((__sk)->sk_portpair == (__ports)) && \ ((__sk)->sk_addrpair == (__cookie)) && \ - (((__sk)->sk_bound_dev_if == (__dif)) || \ - ((__sk)->sk_bound_dev_if == (__sdif))) && \ - net_eq(sock_net(__sk), (__net))) + net_eq(sock_net(__sk), (__net)) && \ + inet_sk_bound_dev_eq((__net), (__sk)->sk_bound_dev_if, (__dif), (__sdif))) #else /* 32-bit arch */ #define INET_ADDR_COOKIE(__name, __saddr, __daddr) \ const int __name __deprecated __attribute__((unused)) @@ -311,9 +310,8 @@ (((__sk)->sk_portpair == (__ports)) && \ ((__sk)->sk_daddr == (__saddr)) && \ ((__sk)->sk_rcv_saddr == (__daddr)) && \ - (((__sk)->sk_bound_dev_if == (__dif)) || \ - ((__sk)->sk_bound_dev_if == (__sdif))) && \ - net_eq(sock_net(__sk), (__net))) + net_eq(sock_net(__sk), (__net)) && \ + inet_sk_bound_dev_eq((__net), (__sk)->sk_bound_dev_if, (__dif), (__sdif))) #endif /* 64-bit arch */
/* Sockets in TCP_CLOSE state are _always_ taken out of the hash, so we need
I can confirm that this gets my testcase working with net.ipv4.tcp_l3mdev_accept=1.
This is to get the testcase to pass, I will leave it to others to comment on the testcase validity in terms of testing forwarding using commands on 1 device.
So a network-namespace-based testcase would be preferred? We used the simple setup because it seemed easier to understand.
The series that 3c82a21f4320 is part of were introduced into the kernel in 2018 by the Vyatta team, who regularly run an extensive test suite for routing protocols for VRF functionality incl. all combinations of route leaking between default and other VRFs, so there is no known issue in this regard. I will attempt to reach out to them so as to advise them of this thread.
Are these testcases public? Perhaps I could use them find a better configuration that handles our use-case. Thanks,
Jan
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