Commit 93fdd47e authored by Herbert Xu's avatar Herbert Xu Committed by David S. Miller
Browse files

bridge: Save frag_max_size between PRE_ROUTING and POST_ROUTING 



As we may defragment the packet in IPv4 PRE_ROUTING and refragment
it after POST_ROUTING we should save the value of frag_max_size.

This is still very wrong as the bridge is supposed to leave the
packets intact, meaning that the right thing to do is to use the
original frag_list for fragmentation.

Unfortunately we don't currently guarantee that the frag_list is
left untouched throughout netfilter so until this changes this is
the best we can do.

There is also a spot in FORWARD where it appears that we can
forward a packet without going through fragmentation, mark it
so that we can fix it later.

Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 88b09a6d

net/bridge/br_netfilter.c

+11 −0
Original line number Diff line number Diff line
@@ -404,6 +404,7 @@ static int br_nf_pre_routing_finish_bridge(struct sk_buff *skb) 
							 ETH_HLEN-ETH_ALEN);

			/* tell br_dev_xmit to continue with forwarding */

			nf_bridge->mask |= BRNF_BRIDGED_DNAT;

			/* FIXME Need to refragment */

			ret = neigh->output(neigh, skb);

		}

		neigh_release(neigh);
@@ -459,6 +460,10 @@ static int br_nf_pre_routing_finish(struct sk_buff *skb) 
	struct nf_bridge_info *nf_bridge = skb->nf_bridge;

	struct rtable *rt;

	int err;

	int frag_max_size;



	frag_max_size = IPCB(skb)->frag_max_size;

	BR_INPUT_SKB_CB(skb)->frag_max_size = frag_max_size;



	if (nf_bridge->mask & BRNF_PKT_TYPE) {

		skb->pkt_type = PACKET_OTHERHOST;
@@ -863,13 +868,19 @@ static unsigned int br_nf_forward_arp(const struct nf_hook_ops *ops, 
static int br_nf_dev_queue_xmit(struct sk_buff *skb)

{

	int ret;

	int frag_max_size;



	/* This is wrong! We should preserve the original fragment

	 * boundaries by preserving frag_list rather than refragmenting.

	 */

	if (skb->protocol == htons(ETH_P_IP) &&

	    skb->len + nf_bridge_mtu_reduction(skb) > skb->dev->mtu &&

	    !skb_is_gso(skb)) {

		frag_max_size = BR_INPUT_SKB_CB(skb)->frag_max_size;

		if (br_parse_ip_options(skb))

			/* Drop invalid packet */

			return NF_DROP;

		IPCB(skb)->frag_max_size = frag_max_size;

		ret = ip_fragment(skb, br_dev_queue_push_xmit);

	} else

		ret = br_dev_queue_push_xmit(skb);

net/bridge/br_private.h

+4 −0
Original line number Diff line number Diff line
@@ -305,10 +305,14 @@ struct net_bridge 


struct br_input_skb_cb {

	struct net_device *brdev;



#ifdef CONFIG_BRIDGE_IGMP_SNOOPING

	int igmp;

	int mrouters_only;

#endif



	u16 frag_max_size;



#ifdef CONFIG_BRIDGE_VLAN_FILTERING

	bool vlan_filtered;

#endif

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