[PATCH] fix IP conntrack+VLAN+bridging problem (was Re: Next problems with ip_conntrack and vlan on 2.6.x)

On Wednesday 19 May 2004 15:57, Adam Osuchowski wrote:
> There is a problem with parentheses. This how it has been
> applied (net/ipv4/ip_output.c):
>
> ll_rs = LL_RESERVED_SPACE(rt->u.dst.dev + nf_bridge_pad(skb))
>
> This expands to:
>
> ll_rs = ((rt->u.dst.dev + nf_bridge_pad(skb))->hard_header_len &
> ~(HH_DATA_MOD - 1)) + HH_DATA_MOD
>
> But, this is how it should look like (after macrodefinition expanding):
>
> ll_rs = ((rt->u.dst.dev->hard_header_len + nf_bridge_pad(skb)) &
> ~(HH_DATA_MOD - 1)) + HH_DATA_MOD
>
> Regards,
> Adam Osuchowski
> Tomasz Dubinski

You are absolutely right.
Dave, please consider applying the patch below which fixes this bug.

cheers,
Bart

--- linux-2.6.6/include/linux/netdevice.h.old	2004-05-21 11:54:56.000000000 +0200
+++ linux-2.6.6/include/linux/netdevice.h	2004-05-21 11:58:08.000000000 +0200
@@ -215,6 +215,8 @@ struct hh_cache
  */
 #define LL_RESERVED_SPACE(dev) \
 	(((dev)->hard_header_len&~(HH_DATA_MOD - 1)) + HH_DATA_MOD)
+#define LL_RESERVED_SPACE_EXTRA(dev,extra) \
+	((((dev)->hard_header_len+extra)&~(HH_DATA_MOD - 1)) + HH_DATA_MOD)
 
 /* These flag bits are private to the generic network queueing
  * layer, they may not be explicitly referenced by any other
--- linux-2.6.6/net/ipv4/ip_output.c.old	2004-05-21 11:54:00.000000000 +0200
+++ linux-2.6.6/net/ipv4/ip_output.c	2004-05-21 11:54:35.000000000 +0200
@@ -567,7 +567,7 @@ slow_path:
 #ifdef CONFIG_BRIDGE_NETFILTER
 	/* for bridged IP traffic encapsulated inside f.e. a vlan header,
 	 * we need to make room for the encapsulating header */
-	ll_rs = LL_RESERVED_SPACE(rt->u.dst.dev + nf_bridge_pad(skb));
+	ll_rs = LL_RESERVED_SPACE_EXTRA(rt->u.dst.dev, nf_bridge_pad(skb));
 	mtu -= nf_bridge_pad(skb);
 #else
 	ll_rs = LL_RESERVED_SPACE(rt->u.dst.dev);



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