diff mbox

IPv6 multicast snooping behaviour on 2.6.39-rc2 and later

Message ID 1314105027.2219.7.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC
State RFC, archived
Delegated to: David Miller
Headers show

Commit Message

Eric Dumazet Aug. 23, 2011, 1:10 p.m. UTC 
Le mardi 23 août 2011 à 21:31 +0900, Ang Way Chuang a écrit :
> Sorry for the blurb. I hope I've configured thunderbird properly to
> send in plain text. Hope you received my reply. I tried your patch on
> 3.0.3 and it didn't fix the problem.


Thanks for trying !

Ok could you please try following patch then ?



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Comments

Ang Way Chuang Aug. 23, 2011, 2:04 p.m. UTC | #1 
Tough luck :( Got no love from bridge. It still doesn't work with your latest patch. Please keep sending those patches.

On 23/08/11 22:10, Eric Dumazet wrote:
> Le mardi 23 août 2011 à 21:31 +0900, Ang Way Chuang a écrit :
>> Sorry for the blurb. I hope I've configured thunderbird properly to
>> send in plain text. Hope you received my reply. I tried your patch on
>> 3.0.3 and it didn't fix the problem.
>
> Thanks for trying !
>
> Ok could you please try following patch then ?
>
> diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
> index 2d85ca7..e9b32a3 100644
> --- a/net/bridge/br_multicast.c
> +++ b/net/bridge/br_multicast.c
> @@ -1497,7 +1497,7 @@ static int br_multicast_ipv6_rcv(struct net_bridge *br,
>   	if (!pskb_may_pull(skb2, offset + sizeof(struct icmp6hdr)))
>   		goto out;
>
> -	len -= offset - skb_network_offset(skb2);
> +	len -= offset;
>
>   	__skb_pull(skb2, offset);
>   	skb_reset_transport_header(skb2);
> @@ -1520,6 +1520,7 @@ static int br_multicast_ipv6_rcv(struct net_bridge *br,
>   		err = pskb_trim_rcsum(skb2, len);
>   		if (err)
>   			goto out;
> +		icmp6h = icmp6_hdr(skb2);
>   	}
>
>   	switch (skb2->ip_summed) {
>
>
>

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Ang Way Chuang Aug. 23, 2011, 5:24 p.m. UTC | #2 
This is what I found so far from debugging.

The packet is not forwarded due to the failed checksum at br_multicast.c:1533

         case CHECKSUM_NONE:
                 skb2->csum = 0;
                 if (skb_checksum_complete(skb2))
                         goto out;
         }

Contrary to description of commit ff9a57a6, when the patch of commit ff9a57a6 is applied,
pskb_trim_rcsum is never called at all on my testbed. When commit ff9a57a6 is reverted,
pskb_trim_rcsum will be called. The difference is:

with commit ff9a57a6,
    pskb_trim_rcsum is never called, br_multicast_ipv6_rcv returns -EINVAL which causes
    br_handle_frame_finish to drop the packet

without commit ff9a57a6,
    pskb_trim_rcsum is called overwriting err with 0. br_multicast_ipv6_rcv still fails on the
    same line (skb_checksum_complete). But the difference is err is set to 0 this time. Thereby,
    allowing the packet to be forwarded.

Anyway, I don't think the behaviour is correct with or without commit ff9a57a6



On 23/08/11 23:04, Ang Way Chuang wrote:
> Tough luck :( Got no love from bridge. It still doesn't work with your latest patch. Please keep sending those patches.
>
> On 23/08/11 22:10, Eric Dumazet wrote:
>> Le mardi 23 août 2011 à 21:31 +0900, Ang Way Chuang a écrit :
>>> Sorry for the blurb. I hope I've configured thunderbird properly to
>>> send in plain text. Hope you received my reply. I tried your patch on
>>> 3.0.3 and it didn't fix the problem.
>>
>> Thanks for trying !
>>
>> Ok could you please try following patch then ?
>>
>> diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
>> index 2d85ca7..e9b32a3 100644
>> --- a/net/bridge/br_multicast.c
>> +++ b/net/bridge/br_multicast.c
>> @@ -1497,7 +1497,7 @@ static int br_multicast_ipv6_rcv(struct net_bridge *br,
>>       if (!pskb_may_pull(skb2, offset + sizeof(struct icmp6hdr)))
>>           goto out;
>>
>> -    len -= offset - skb_network_offset(skb2);
>> +    len -= offset;
>>
>>       __skb_pull(skb2, offset);
>>       skb_reset_transport_header(skb2);
>> @@ -1520,6 +1520,7 @@ static int br_multicast_ipv6_rcv(struct net_bridge *br,
>>           err = pskb_trim_rcsum(skb2, len);
>>           if (err)
>>               goto out;
>> +        icmp6h = icmp6_hdr(skb2);
>>       }
>>
>>       switch (skb2->ip_summed) {
>>
>>
>>
>
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diff mbox

Patch

diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index 2d85ca7..e9b32a3 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -1497,7 +1497,7 @@  static int br_multicast_ipv6_rcv(struct net_bridge *br,
 	if (!pskb_may_pull(skb2, offset + sizeof(struct icmp6hdr)))
 		goto out;
 
-	len -= offset - skb_network_offset(skb2);
+	len -= offset;
 
 	__skb_pull(skb2, offset);
 	skb_reset_transport_header(skb2);
@@ -1520,6 +1520,7 @@  static int br_multicast_ipv6_rcv(struct net_bridge *br,
 		err = pskb_trim_rcsum(skb2, len);
 		if (err)
 			goto out;
+		icmp6h = icmp6_hdr(skb2);
 	}
 
 	switch (skb2->ip_summed) {