From: David Miller <davem@davemloft.net>
To: lifonghsu@synology.com
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: net: fix routing encapsulated packets when binding a socket to a tunnel interface
Date: Mon, 25 Mar 2019 16:16:42 -0700 (PDT) [thread overview]
Message-ID: <20190325.161642.2075740479846080205.davem@davemloft.net> (raw)
In-Reply-To: <1553236198-5955-1-git-send-email-lifonghsu@synology.com>
From: lifonghsu <lifonghsu@synology.com>
Date: Fri, 22 Mar 2019 14:29:58 +0800
> From: LiFong Hsu <lifonghsu@synology.com>
>
> When binding a socket to a 4in6/6in4 tunnel interface, the kernel sends
> the packet to the tunnel interface without any problem, e.g.,
> ping 8.8.8.8 -I 4in6. However, after the 4in6/6in4 tunnel encapsulation,
> the encapsulated packet could be sent to the tunnel interface again when
> some fields of the skb were changed in mangle table's output chain,
> such as skb->mark and src/dest IP address. Sending to the tunnel interface
> twice is unexpected, since there are no corresponding routing rules on
> the tunnel interface for the encapsulated packet. Eventually, the encapsulated
> packet will be dropped by the tunnel interface.
>
> This commit stops referring to sk_bound_dev_if while re-routing a packet
> with skb_iif!=0 which indicates that the packet has already been sent to
> the interface specified by sk_bound_dev_if. Instead, this commit sends
> the packet to the underlying network device.
>
> Signed-off-by: LiFong Hsu <lifonghsu@synology.com>
> Reviewed-by: JianJhen Chen <kchen@synology.com>
skb->skb_iif is a receive side indication, why would it be changed on
transmit?
I see mac802154 doing this, but what it's doing is somewhat broken and
that doesn't come into play in your example.
next prev parent reply other threads:[~2019-03-25 23:16 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-22 6:29 net: fix routing encapsulated packets when binding a socket to a tunnel interface lifonghsu
2019-03-25 23:16 ` David Miller [this message]
2019-03-27 20:44 ` David Miller
2019-03-28 8:30 ` lifonghsu
2019-03-29 17:40 ` David Miller
2019-04-01 3:00 ` lifonghsu
2019-04-01 6:01 ` David Miller
2019-04-01 9:52 ` lifonghsu
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