netdev - Re: [PATCH net-next] openvswitch: fix vport packet length check.

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Message-ID: <CALDO+SY=nAOAEkD+an2rawBYn+eGxZneK0RtFwx=LUnwW0DxMg@mail.gmail.com>
Date:   Wed, 7 Mar 2018 14:42:21 -0800
From:   William Tu <u9012063@...il.com>
To:     Pravin Shelar <pshelar@....org>
Cc:     Linux Kernel Network Developers <netdev@...r.kernel.org>,
        Jiri Benc <jbenc@...hat.com>
Subject: Re: [PATCH net-next] openvswitch: fix vport packet length check.

On Wed, Mar 7, 2018 at 1:18 PM, Pravin Shelar <pshelar@....org> wrote:
> On Tue, Mar 6, 2018 at 5:56 PM, William Tu <u9012063@...il.com> wrote:
>> When sending a packet to a tunnel device, the dev's hard_header_len
>> could be larger than the skb->len in function packet_length().
>> In the case of ip6gretap/erspan, hard_header_len = LL_MAX_HEADER + t_hlen,
>> which is around 180, and an ARP packet sent to this tunnel has
>> skb->len = 42.  This causes the 'unsign int length' to become super
>> large because it is negative value, causing the later ovs_vport_send
>> to drop it due to over-mtu size.  The patch fixes it by setting it to 0.
>>
>> Signed-off-by: William Tu <u9012063@...il.com>
>> ---
>>  net/openvswitch/vport.c | 4 ++--
>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/net/openvswitch/vport.c b/net/openvswitch/vport.c
>> index b6c8524032a0..7718d5b4cf8a 100644
>> --- a/net/openvswitch/vport.c
>> +++ b/net/openvswitch/vport.c
>> @@ -467,7 +467,7 @@ int ovs_vport_receive(struct vport *vport, struct sk_buff *skb,
>>  static unsigned int packet_length(const struct sk_buff *skb,
>>                                   struct net_device *dev)
> Can you also change return type of this function?
>

OK, I will change to int. Thanks