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[NETFILTER]: reduce netfilter sk_buff enlargement

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As discussed at netconf'05, we're trying to save every bit in sk_buff.
The patch below makes sk_buff 8 bytes smaller.  I did some basic
testing on my notebook and it seems to work.

The only real in-tree user of nfcache was IPVS, who only needs a
single bit.  Unfortunately I couldn't find some other free bit in
sk_buff to stuff that bit into, so I introduced a separate field for
them.  Maybe the IPVS guys can resolve that to further save space.

Initially I wanted to shrink pkt_type to three bits (PACKET_HOST and
alike are only 6 values defined), but unfortunately the bluetooth code
overloads pkt_type :(

The conntrack-event-api (out-of-tree) uses nfcache, but Rusty just
came up with a way how to do it without any skb fields, so it's safe
to remove it.

- remove all never-implemented 'nfcache' code
- don't have ipvs code abuse 'nfcache' field. currently get's their own
  compile-conditional skb->ipvs_property field.  IPVS maintainers can
  decide to move this bit elswhere, but nfcache needs to die.
- remove skb->nfcache field to save 4 bytes
- move skb->nfctinfo into three unused bits to save further 4 bytes

Signed-off-by: Harald Welte <laforge@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Harald Welte
2005-08-09 19:24:19 -07:00
committed by David S. Miller
parent bf3a46aa9b
commit 6869c4d8e0
27 changed files with 36 additions and 64 deletions
Download Patch File Download Diff File Expand all files Collapse all files

16
net/ipv6/ip6_output.c
View File

@@ -185,19 +185,6 @@ int ip6_route_me_harder(struct sk_buff *skb)
}
#endif
static inline int ip6_maybe_reroute(struct sk_buff *skb)
{
#ifdef CONFIG_NETFILTER
if (skb->nfcache & NFC_ALTERED){
if (ip6_route_me_harder(skb) != 0){
kfree_skb(skb);
return -EINVAL;
}
}
#endif /* CONFIG_NETFILTER */
return dst_output(skb);
}
/*
* xmit an sk_buff (used by TCP)
*/
@@ -266,7 +253,8 @@ int ip6_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl,
mtu = dst_mtu(dst);
if ((skb->len <= mtu) || ipfragok) {
IP6_INC_STATS(IPSTATS_MIB_OUTREQUESTS);
return NF_HOOK(PF_INET6, NF_IP6_LOCAL_OUT, skb, NULL, dst->dev, ip6_maybe_reroute);
return NF_HOOK(PF_INET6, NF_IP6_LOCAL_OUT, skb, NULL, dst->dev,
dst_output);
}
if (net_ratelimit())