From: David Miller <davem@davemloft.net>
To: nicolas.dichtel@6wind.com
Cc: netdev@vger.kernel.org
Subject: Re: [PATCH net] ipv6: fix neighbour resolution with raw socket
Date: Sat, 22 Jun 2019 17:07:12 -0700 (PDT) [thread overview]
Message-ID: <20190622.170712.2073255657139689928.davem@davemloft.net> (raw)
In-Reply-To: <20190620123434.7219-1-nicolas.dichtel@6wind.com>
From: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Date: Thu, 20 Jun 2019 14:34:34 +0200
> The scenario is the following: the user uses a raw socket to send an ipv6
> packet, destinated to a not-connected network, and specify a connected nh.
> Here is the corresponding python script to reproduce this scenario:
...
> fd00:175::/64 is a connected route and fd00:200::fa is not a connected
> host.
>
> With this scenario, the kernel starts by sending a NS to resolve
> fd00:175::2. When it receives the NA, it flushes its queue and try to send
> the initial packet. But instead of sending it, it sends another NS to
> resolve fd00:200::fa, which obvioulsy fails, thus the packet is dropped. If
> the user sends again the packet, it now uses the right nh (fd00:175::2).
>
> The problem is that ip6_dst_lookup_neigh() uses the rt6i_gateway, which is
> :: because the associated route is a connected route, thus it uses the dst
> addr of the packet. Let's use rt6_nexthop() to choose the right nh.
>
> Note that rt and in6addr_any are const in ip6_dst_lookup_neigh(), thus
> let's constify rt6_nexthop() to avoid ugly cast.
>
> Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Applied and queued up for -stable, thanks.
next prev parent reply other threads:[~2019-06-23 0:07 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-20 12:34 [PATCH net] ipv6: fix neighbour resolution with raw socket Nicolas Dichtel
2019-06-20 15:12 ` David Ahern
2019-06-20 15:42 ` Nicolas Dichtel
2019-06-20 16:36 ` David Ahern
2019-06-20 16:47 ` David Ahern
2019-06-21 8:09 ` Nicolas Dichtel
2019-06-21 18:48 ` kbuild test robot
2019-06-23 0:07 ` David Miller [this message]
2019-06-23 0:08 ` David Miller
2019-06-24 14:01 ` [PATCH net v2 0/2] " Nicolas Dichtel
2019-06-24 14:01 ` [PATCH net v2 1/2] ipv6: constify rt6_nexthop() Nicolas Dichtel
2019-06-24 16:45 ` Nick Desaulniers
2019-06-24 17:06 ` David Miller
2019-06-24 17:17 ` Nick Desaulniers
2019-06-24 17:22 ` David Miller
2019-06-24 17:37 ` Nick Desaulniers
2019-06-24 18:18 ` Nicolas Dichtel
2019-06-24 20:27 ` David Miller
2019-06-24 14:01 ` [PATCH net v2 2/2] ipv6: fix neighbour resolution with raw socket Nicolas Dichtel
2019-06-26 20:26 ` [PATCH net v2 0/2] " David Miller
2019-10-14 9:34 ` Nicolas Dichtel
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