From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bart De Schuymer Subject: Re: 2.6.0-test9 : bridge freezes Date: Tue, 16 Dec 2003 08:43:58 +0100 Sender: netdev-bounce@oss.sgi.com Message-ID: <200312160843.58992.bdschuym@pandora.be> References: <20031215171732.4877acd1.davem@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Cc: netdev@oss.sgi.com Return-path: To: "David S. Miller" , Steve Hill In-Reply-To: <20031215171732.4877acd1.davem@redhat.com> Content-Disposition: inline Errors-to: netdev-bounce@oss.sgi.com List-Id: netdev.vger.kernel.org On Tuesday 16 December 2003 02:17, David S. Miller wrote: > There must be something in particular that the IPV4 fragmentation code > is doing that makes these fragment reference drops get forgotten. Hmmm... > > I just noticed that both bridge netfilter and IPV4 fragmentation make much > use of the skb->cb[] control block, this may be the true source of the > troubles. > > In fact, since bridge netfilter expects pointers to be there, I'm surprised > this does not cause a crash. It only expects a pointer in br_nf_forward_finish() for ARP traffic. I checked and the ARP code doesn't use the control buffer. For IP traffic, it uses the control buffer just before and just after the call to the IP PRE_ROUTING hook. OK, I just looked at the ip_fragment.c code and it uses the control buffer too. You are truly amazing. I'll use skbuff.c::nf_bridge_info instead. Steve, does this patch fix things? Of course, first remove your code from ip_fragment.c. I haven't tested this patch yet, this will have to wait until this evening. Dave, I'll cook up a slightly different patch for you later, I think nf_bridge->hh is now a bad name, I'll change it into nf_bridge->data. thanks, Bart --- linux-2.6.0-test11-bk10/net/bridge/br_netfilter.c.old 2003-12-16 08:33:35.000000000 +0100 +++ linux-2.6.0-test11-bk10/net/bridge/br_netfilter.c 2003-12-16 08:34:12.000000000 +0100 @@ -38,11 +38,9 @@ #define skb_origaddr(skb) (((struct bridge_skb_cb *) \ - (skb->cb))->daddr.ipv4) + (skb->nf_bridge->hh))->daddr.ipv4) #define store_orig_dstaddr(skb) (skb_origaddr(skb) = (skb)->nh.iph->daddr) #define dnat_took_place(skb) (skb_origaddr(skb) != (skb)->nh.iph->daddr) -#define clear_cb(skb) (memset(&skb_origaddr(skb), 0, \ - sizeof(struct bridge_skb_cb))) #define has_bridge_parent(device) ((device)->br_port != NULL) #define bridge_parent(device) ((device)->br_port->br->dev) @@ -203,7 +201,6 @@ bridged_dnat: */ nf_bridge->mask |= BRNF_BRIDGED_DNAT; skb->dev = nf_bridge->physindev; - clear_cb(skb); if (skb->protocol == __constant_htons(ETH_P_8021Q)) { skb_push(skb, VLAN_HLEN); @@ -224,7 +221,6 @@ bridged_dnat: dst_hold(skb->dst); } - clear_cb(skb); skb->dev = nf_bridge->physindev; if (skb->protocol == __constant_htons(ETH_P_8021Q)) { skb_push(skb, VLAN_HLEN);