netdev - Re: [PATCH v2] openvswitch: supply a dummy err_handler of gre_cisco

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Date:	Sat, 5 Apr 2014 12:20:27 +0800 (CST)
From:	"wei zhang" <asuka.com@....com>
To:	"Jesse Gross" <jesse@...ira.com>
Cc:	"David Miller" <davem@...emloft.net>,
	"dev@...nvswitch.org" <dev@...nvswitch.org>,
	netdev <netdev@...r.kernel.org>,
	"Linux Kernel Mailing List" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] openvswitch: supply a dummy err_handler of
 gre_cisco_protocol to prevent kernel crash

At 2014-04-05 07:05:59,"Jesse Gross" <jesse@...ira.com> wrote:
>On Tue, Apr 1, 2014 at 5:23 PM, Wei Zhang <asuka.com@....com> wrote:
>>
>> v2 -> v1: use the same logic of the gre_rcv() to distinguish which packet is
>> intended to us!
>
>As a tip on kernel process: if you put the version information after
>three dashes below the signed-off-by line then git will automatically
>remove it when the final patch is applied.

Thanks, should I modify it and send a v3 patch?

>
>> diff --git a/net/openvswitch/vport-gre.c b/net/openvswitch/vport-gre.c
>> index a3d6951..f391df1 100644
>> --- a/net/openvswitch/vport-gre.c
>> +++ b/net/openvswitch/vport-gre.c
>> @@ -110,6 +110,21 @@ static int gre_rcv(struct sk_buff *skb,
>>         return PACKET_RCVD;
>>  }
>>
>> +/* Called with rcu_read_lock and BH disabled. */
>> +static int gre_err(struct sk_buff *skb, u32 info,
>> +                  const struct tnl_ptk_info *tpi)
>> +{
>> +       struct ovs_net *ovs_net;
>> +       struct vport *vport;
>> +
>> +       ovs_net = net_generic(dev_net(skb->dev), ovs_net_id);
>> +       vport = rcu_dereference(ovs_net->vport_net.gre_vport);
>> +       if (unlikely(!vport))
>> +               return PACKET_REJECT;
>> +       else
>> +               return PACKET_RCVD;
>
>Sorry, I forgot to say this before - if we receive the packet then we
>should also call consume_skb() on it.

Maybe there is no need to call consume_skb()? The icmp_rcv() would
call kfree_skb() for us. I also checked the ipgre_err(), it return 
PACKET_RCVD without call consume_skb() too.

Regards,
Wei Zhang