netdev - Re: [PATCH net-next] net: Fix vti use case with oif in dst lookups for IPv6

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Date:	Sun, 11 Oct 2015 07:31:32 -0600
From:	David Ahern <dsa@...ulusnetworks.com>
To:	Hajime Tazaki <thehajime@...il.com>
Cc:	steffen.klassert@...unet.com, netdev@...r.kernel.org
Subject: Re: [PATCH net-next] net: Fix vti use case with oif in dst lookups
 for IPv6

On 10/11/15 7:22 AM, Hajime Tazaki wrote:
>
> At Fri, 9 Oct 2015 11:27:36 -0600,
> David Ahern wrote:
>>
>> [1  <text/plain; windows-1252 (7bit)>]
>> On 10/9/15 1:17 AM, Steffen Klassert wrote:
>>>>> diff --git a/net/ipv6/xfrm6_policy.c b/net/ipv6/xfrm6_policy.c
>>>>> index 30caa289c5db..5cedfda4b241 100644
>>>>> --- a/net/ipv6/xfrm6_policy.c
>>>>> +++ b/net/ipv6/xfrm6_policy.c
>>>>> @@ -37,6 +37,7 @@ static struct dst_entry *xfrm6_dst_lookup(struct net *net, int tos, int oif,
>>>>>
>>>>>    	memset(&fl6, 0, sizeof(fl6));
>>>>>    	fl6.flowi6_oif = oif;
>>>>> +	fl6.flowi6_flags = FLOWI_FLAG_SKIP_NH_OIF;
>>>>>    	memcpy(&fl6.daddr, daddr, sizeof(fl6.daddr));
>>>>>    	if (saddr)
>>>>>    		memcpy(&fl6.saddr, saddr, sizeof(fl6.saddr));
>>>>
>>>> I found that this fix is still not sufficient with the mip6
>>>> (Mobile IPv6) use case.
>>>
>>> It does not even fix the vti case. The behaviour of the vti devices is
>>> the same, with and without the patch.
>>>
>>
>> The attached patch applied to Linus' tree works for me. Currently the
>> above change is not in his tree, so I added it to this patch. Once you
>> confirm that it works for you I'll create the delta-patch for net and
>> send out.
>
> I gave it a try but without any luck unfortunately.
> I may need to look carefully what mip6 does here.
>
> the code path where I'm looking at for MH packet (raw socket
> with IPPROTO_MH) is:
>
> #0  ip6_route_output (net=0x7ffff3a40a40 <rumpns_init_net>, sk=0x7ffff30b5c50, fl6=0x7ffff0ed2fe0) at net/ipv6/route.c:1195
> #1  0x00007ffff35d155f in ip6_dst_lookup_tail (net=0x7ffff3a40a40 <rumpns_init_net>, sk=0x7ffff30b5c50, dst=0x7ffff0ed2f18, fl6=0x7ffff0ed2fe0)
>      at net/ipv6/ip6_output.c:929
> #2  0x00007ffff35d1707 in ip6_dst_lookup_flow (sk=0x7ffff30b5c50, fl6=0x7ffff0ed2fe0, final_dst=0x0) at net/ipv6/ip6_output.c:1024
> #3  0x00007ffff36199f7 in rawv6_sendmsg (sk=0x7ffff30b5c50, msg=0x7ffff0ed3320, len=32) at net/ipv6/raw.c:872
> #4  0x00007ffff3526d21 in inet_sendmsg (sock=0x7ffff30b5810, msg=0x7ffff0ed3320, size=32) at net/ipv4/af_inet.c:737
> #5  0x00007ffff338dc8a in sock_sendmsg_nosec (msg=0x7ffff0ed3320, sock=0x7ffff30b5810) at net/socket.c:610
> #6  sock_sendmsg (sock=0x7ffff30b5810, msg=0x7ffff0ed3320) at net/socket.c:620
>
>
> which (*dst)->error of ip6_route_output gives -22 (EINVAL).
>
> I will be back once I got any findings.

How does a xfrm change affect this code path?

Can you apply this patch, and then run:

perf record -e fib6:* -a -g
perf script

Thanks,
David



View attachment "0001-net-IPv6-fib-and-route-tracepoints.patch" of type "text/plain" (10293 bytes)