From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ang Way Chuang Subject: Re: IPv6 multicast snooping behaviour on 2.6.39-rc2 and later Date: Wed, 24 Aug 2011 16:38:39 +0900 Message-ID: <4E54AA7F.80107@sfc.wide.ad.jp> References: <4E5367CA.3090005@sfc.wide.ad.jp> <1314093424.2219.3.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> <4E539DA8.1070504@sfc.wide.ad.jp> <1314105027.2219.7.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> <4E53B360.8090107@sfc.wide.ad.jp> <4E53E237.1060401@sfc.wide.ad.jp> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Eric Dumazet , netdev@vger.kernel.org, =?ISO-8859-1?Q?Linus_L=FCssing?= , Herbert Xu To: "Yan, Zheng " Return-path: Received: from shonan.sfc.wide.ad.jp ([203.178.142.130]:53602 "EHLO mail.sfc.wide.ad.jp" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750835Ab1HXHim (ORCPT ); Wed, 24 Aug 2011 03:38:42 -0400 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: Thanks Zheng Yan. Your patch works as well. I trust others' code more than mine, so please ignore the patch that I sent earlier. On 24/08/11 16:04, Yan, Zheng wrote: > On Wed, Aug 24, 2011 at 1:24 AM, Ang Way Chuang wrote: >> 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 >> >> > Looks like a checksum calculation bug. Please try below patch, Thanks. > > --- > diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c > index 2d85ca7..22d2d1a 100644 > --- a/net/bridge/br_multicast.c > +++ b/net/bridge/br_multicast.c > @@ -1520,16 +1520,23 @@ static int br_multicast_ipv6_rcv(struct net_bridge *br, > err = pskb_trim_rcsum(skb2, len); > if (err) > goto out; > + err = -EINVAL; > } > > + ip6h = ipv6_hdr(skb2); > + > switch (skb2->ip_summed) { > case CHECKSUM_COMPLETE: > - if (!csum_fold(skb2->csum)) > + if (!csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr, skb2->len, > + IPPROTO_ICMPV6, skb2->csum)) > break; > /*FALLTHROUGH*/ > case CHECKSUM_NONE: > - skb2->csum = 0; > - if (skb_checksum_complete(skb2)) > + skb2->csum = ~csum_unfold(csum_ipv6_magic(&ip6h->saddr, > + &ip6h->daddr, > + skb2->len, > + IPPROTO_ICMPV6, 0)); > + if (__skb_checksum_complete(skb2)) > goto out; > } > > --- > -- > To unsubscribe from this list: send the line "unsubscribe netdev" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >