Commit 6869c4d8 authored by Harald Welte's avatar Harald Welte Committed by David S. Miller
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[NETFILTER]: reduce netfilter sk_buff enlargement



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: default avatarHarald Welte <laforge@netfilter.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent bf3a46aa
......@@ -21,10 +21,13 @@
#define NF_STOP 5
#define NF_MAX_VERDICT NF_STOP
/* only for userspace compatibility */
#ifndef __KERNEL__
/* Generic cache responses from hook functions.
<= 0x2000 is used for protocol-flags. */
#define NFC_UNKNOWN 0x4000
#define NFC_ALTERED 0x8000
#endif
#ifdef __KERNEL__
#include <linux/config.h>
......
......@@ -9,6 +9,8 @@
#include <linux/netfilter.h>
/* only for userspace compatibility */
#ifndef __KERNEL__
/* IP Cache bits. */
/* Src IP address. */
#define NFC_DN_SRC 0x0001
......@@ -18,6 +20,7 @@
#define NFC_DN_IF_IN 0x0004
/* Output device. */
#define NFC_DN_IF_OUT 0x0008
#endif /* ! __KERNEL__ */
/* DECnet Hooks */
/* After promisc drops, checksum checks. */
......
......@@ -8,6 +8,8 @@
#include <linux/config.h>
#include <linux/netfilter.h>
/* only for userspace compatibility */
#ifndef __KERNEL__
/* IP Cache bits. */
/* Src IP address. */
#define NFC_IP_SRC 0x0001
......@@ -35,6 +37,7 @@
#define NFC_IP_DST_PT 0x0400
/* Something else about the proto */
#define NFC_IP_PROTO_UNKNOWN 0x2000
#endif /* ! __KERNEL__ */
/* IP Hooks */
/* After promisc drops, checksum checks. */
......
......@@ -10,6 +10,8 @@
#include <linux/netfilter.h>
/* only for userspace compatibility */
#ifndef __KERNEL__
/* IP Cache bits. */
/* Src IP address. */
#define NFC_IP6_SRC 0x0001
......@@ -38,6 +40,7 @@
#define NFC_IP6_DST_PT 0x0400
/* Something else about the proto */
#define NFC_IP6_PROTO_UNKNOWN 0x2000
#endif /* ! __KERNEL__ */
/* IP6 Hooks */
......
......@@ -190,7 +190,6 @@ struct skb_shared_info {
* @end: End pointer
* @destructor: Destruct function
* @nfmark: Can be used for communication between hooks
* @nfcache: Cache info
* @nfct: Associated connection, if any
* @nfctinfo: Relationship of this skb to the connection
* @nf_bridge: Saved data about a bridged frame - see br_netfilter.c
......@@ -252,17 +251,18 @@ struct sk_buff {
__u8 local_df:1,
cloned:1,
ip_summed:2,
nohdr:1;
/* 3 bits spare */
nohdr:1,
nfctinfo:3;
__u8 pkt_type;
__be16 protocol;
void (*destructor)(struct sk_buff *skb);
#ifdef CONFIG_NETFILTER
__u32 nfmark;
__u32 nfcache;
__u32 nfctinfo;
struct nf_conntrack *nfct;
#if defined(CONFIG_IP_VS) || defined(CONFIG_IP_VS_MODULE)
__u8 ipvs_property:1;
#endif
#ifdef CONFIG_BRIDGE_NETFILTER
struct nf_bridge_info *nf_bridge;
#endif
......
......@@ -23,10 +23,9 @@ static int ebt_target_mark(struct sk_buff **pskb, unsigned int hooknr,
{
struct ebt_mark_t_info *info = (struct ebt_mark_t_info *)data;
if ((*pskb)->nfmark != info->mark) {
if ((*pskb)->nfmark != info->mark)
(*pskb)->nfmark = info->mark;
(*pskb)->nfcache |= NFC_ALTERED;
}
return info->target;
}
......
......@@ -361,7 +361,6 @@ struct sk_buff *skb_clone(struct sk_buff *skb, unsigned int __nocast gfp_mask)
n->destructor = NULL;
#ifdef CONFIG_NETFILTER
C(nfmark);
C(nfcache);
C(nfct);
nf_conntrack_get(skb->nfct);
C(nfctinfo);
......@@ -424,7 +423,6 @@ static void copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
new->destructor = NULL;
#ifdef CONFIG_NETFILTER
new->nfmark = old->nfmark;
new->nfcache = old->nfcache;
new->nfct = old->nfct;
nf_conntrack_get(old->nfct);
new->nfctinfo = old->nfctinfo;
......
......@@ -392,7 +392,6 @@ static void ip_copy_metadata(struct sk_buff *to, struct sk_buff *from)
#endif
#ifdef CONFIG_NETFILTER
to->nfmark = from->nfmark;
to->nfcache = from->nfcache;
/* Connection association is same as pre-frag packet */
nf_conntrack_put(to->nfct);
to->nfct = from->nfct;
......
......@@ -22,6 +22,7 @@
*
* Changes:
* Paul `Rusty' Russell properly handle non-linear skbs
* Harald Welte don't use nfcache
*
*/
......@@ -529,7 +530,7 @@ static unsigned int ip_vs_post_routing(unsigned int hooknum,
const struct net_device *out,
int (*okfn)(struct sk_buff *))
{
if (!((*pskb)->nfcache & NFC_IPVS_PROPERTY))
if (!((*pskb)->ipvs_property))
return NF_ACCEPT;
/* The packet was sent from IPVS, exit this chain */
......@@ -701,7 +702,7 @@ static int ip_vs_out_icmp(struct sk_buff **pskb, int *related)
/* do the statistics and put it back */
ip_vs_out_stats(cp, skb);
skb->nfcache |= NFC_IPVS_PROPERTY;
skb->ipvs_property = 1;
verdict = NF_ACCEPT;
out:
......@@ -739,7 +740,7 @@ ip_vs_out(unsigned int hooknum, struct sk_buff **pskb,
EnterFunction(11);
if (skb->nfcache & NFC_IPVS_PROPERTY)
if (skb->ipvs_property)
return NF_ACCEPT;
iph = skb->nh.iph;
......@@ -821,7 +822,7 @@ ip_vs_out(unsigned int hooknum, struct sk_buff **pskb,
ip_vs_set_state(cp, IP_VS_DIR_OUTPUT, skb, pp);
ip_vs_conn_put(cp);
skb->nfcache |= NFC_IPVS_PROPERTY;
skb->ipvs_property = 1;
LeaveFunction(11);
return NF_ACCEPT;
......
......@@ -127,7 +127,7 @@ ip_vs_dst_reset(struct ip_vs_dest *dest)
#define IP_VS_XMIT(skb, rt) \
do { \
(skb)->nfcache |= NFC_IPVS_PROPERTY; \
(skb)->ipvs_property = 1; \
(skb)->ip_summed = CHECKSUM_NONE; \
NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, (skb), NULL, \
(rt)->u.dst.dev, dst_output); \
......
......@@ -625,9 +625,6 @@ unsigned int ip_conntrack_in(unsigned int hooknum,
return NF_DROP;
}
/* FIXME: Do this right please. --RR */
(*pskb)->nfcache |= NFC_UNKNOWN;
/* Doesn't cover locally-generated broadcast, so not worth it. */
#if 0
/* Ignore broadcast: no `connection'. */
......@@ -943,10 +940,8 @@ ip_ct_gather_frags(struct sk_buff *skb, u_int32_t user)
skb = ip_defrag(skb, user);
local_bh_enable();
if (skb) {
if (skb)
ip_send_check(skb->nh.iph);
skb->nfcache |= NFC_ALTERED;
}
return skb;
}
......
......@@ -321,7 +321,6 @@ manip_pkt(u_int16_t proto,
{
struct iphdr *iph;
(*pskb)->nfcache |= NFC_ALTERED;
if (!skb_ip_make_writable(pskb, iphdroff + sizeof(*iph)))
return 0;
......
......@@ -73,8 +73,6 @@ ip_nat_fn(unsigned int hooknum,
IP_NF_ASSERT(!((*pskb)->nh.iph->frag_off
& htons(IP_MF|IP_OFFSET)));
(*pskb)->nfcache |= NFC_UNKNOWN;
/* If we had a hardware checksum before, it's now invalid */
if ((*pskb)->ip_summed == CHECKSUM_HW)
if (skb_checksum_help(*pskb, (out == NULL)))
......
......@@ -392,7 +392,6 @@ ipq_mangle_ipv4(ipq_verdict_msg_t *v, struct ipq_queue_entry *e)
return -ENOMEM;
memcpy(e->skb->data, v->payload, v->data_len);
e->skb->ip_summed = CHECKSUM_NONE;
e->skb->nfcache |= NFC_ALTERED;
/*
* Extra routing may needed on local out, as the QUEUE target never
......
......@@ -312,7 +312,6 @@ ipt_do_table(struct sk_buff **pskb,
do {
IP_NF_ASSERT(e);
IP_NF_ASSERT(back);
(*pskb)->nfcache |= e->nfcache;
if (ip_packet_match(ip, indev, outdev, &e->ip, offset)) {
struct ipt_entry_target *t;
......
......@@ -32,10 +32,8 @@ target(struct sk_buff **pskb,
{
const struct ipt_classify_target_info *clinfo = targinfo;
if((*pskb)->priority != clinfo->priority) {
if((*pskb)->priority != clinfo->priority)
(*pskb)->priority = clinfo->priority;
(*pskb)->nfcache |= NFC_ALTERED;
}
return IPT_CONTINUE;
}
......
......@@ -61,10 +61,8 @@ target(struct sk_buff **pskb,
case IPT_CONNMARK_RESTORE:
nfmark = (*pskb)->nfmark;
diff = (ct->mark ^ nfmark) & markinfo->mask;
if (diff != 0) {
if (diff != 0)
(*pskb)->nfmark = nfmark ^ diff;
(*pskb)->nfcache |= NFC_ALTERED;
}
break;
}
}
......
......@@ -51,7 +51,6 @@ target(struct sk_buff **pskb,
sizeof(diffs),
(*pskb)->nh.iph->check
^ 0xFFFF));
(*pskb)->nfcache |= NFC_ALTERED;
}
return IPT_CONTINUE;
}
......
......@@ -43,7 +43,6 @@ set_ect_ip(struct sk_buff **pskb, const struct ipt_ECN_info *einfo)
sizeof(diffs),
(*pskb)->nh.iph->check
^0xFFFF));
(*pskb)->nfcache |= NFC_ALTERED;
}
return 1;
}
......@@ -87,7 +86,6 @@ set_ect_tcp(struct sk_buff **pskb, const struct ipt_ECN_info *einfo, int inward)
tcph->check = csum_fold(csum_partial((char *)diffs,
sizeof(diffs),
tcph->check^0xFFFF));
(*pskb)->nfcache |= NFC_ALTERED;
return 1;
}
......
......@@ -29,10 +29,9 @@ target_v0(struct sk_buff **pskb,
{
const struct ipt_mark_target_info *markinfo = targinfo;
if((*pskb)->nfmark != markinfo->mark) {
if((*pskb)->nfmark != markinfo->mark)
(*pskb)->nfmark = markinfo->mark;
(*pskb)->nfcache |= NFC_ALTERED;
}
return IPT_CONTINUE;
}
......@@ -61,10 +60,9 @@ target_v1(struct sk_buff **pskb,
break;
}
if((*pskb)->nfmark != mark) {
if((*pskb)->nfmark != mark)
(*pskb)->nfmark = mark;
(*pskb)->nfcache |= NFC_ALTERED;
}
return IPT_CONTINUE;
}
......
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