[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: Harald Welte <laforge@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

22 files changed, 19 insertions, 59 deletions

diff --git a/net/bridge/netfilter/ebt_mark.c b/net/bridge/netfilter/ebt_mark.c
index 02c632b4d325..c93d35ab95c0 100644
--- a/net/bridge/netfilter/ebt_mark.c
+++ b/net/bridge/netfilter/ebt_mark.c
@@ -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;
 }
 
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 7eab867ede59..096991cb09d9 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -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;
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index 80d13103b2b0..766564cb4207 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -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;
diff --git a/net/ipv4/ipvs/ip_vs_core.c b/net/ipv4/ipvs/ip_vs_core.c
index 5fb257dd07cb..3ac7eeca04ac 100644
--- a/net/ipv4/ipvs/ip_vs_core.c
+++ b/net/ipv4/ipvs/ip_vs_core.c
@@ -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;
diff --git a/net/ipv4/ipvs/ip_vs_xmit.c b/net/ipv4/ipvs/ip_vs_xmit.c
index a8512a3fd08a..3b87482049cf 100644
--- a/net/ipv4/ipvs/ip_vs_xmit.c
+++ b/net/ipv4/ipvs/ip_vs_xmit.c
@@ -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);           \
diff --git a/net/ipv4/netfilter/ip_conntrack_core.c b/net/ipv4/netfilter/ip_conntrack_core.c
index a7f0c821a9b2..04c3414361d4 100644
--- a/net/ipv4/netfilter/ip_conntrack_core.c
+++ b/net/ipv4/netfilter/ip_conntrack_core.c
@@ -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;
 }
 
diff --git a/net/ipv4/netfilter/ip_nat_core.c b/net/ipv4/netfilter/ip_nat_core.c
index 739b6dde1c82..ed4d731880f7 100644
--- a/net/ipv4/netfilter/ip_nat_core.c
+++ b/net/ipv4/netfilter/ip_nat_core.c
@@ -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;
 
diff --git a/net/ipv4/netfilter/ip_nat_standalone.c b/net/ipv4/netfilter/ip_nat_standalone.c
index 91d5ea1dbbc9..9ecba979033a 100644
--- a/net/ipv4/netfilter/ip_nat_standalone.c
+++ b/net/ipv4/netfilter/ip_nat_standalone.c
@@ -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)))
diff --git a/net/ipv4/netfilter/ip_queue.c b/net/ipv4/netfilter/ip_queue.c
index c6baa8174389..bc0af8d8e910 100644
--- a/net/ipv4/netfilter/ip_queue.c
+++ b/net/ipv4/netfilter/ip_queue.c
@@ -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
diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c
index c88dfcd38c56..ff8d85d2070d 100644
--- a/net/ipv4/netfilter/ip_tables.c
+++ b/net/ipv4/netfilter/ip_tables.c
@@ -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;
 
diff --git a/net/ipv4/netfilter/ipt_CLASSIFY.c b/net/ipv4/netfilter/ipt_CLASSIFY.c
index 9842e6e23184..dab78d8bd494 100644
--- a/net/ipv4/netfilter/ipt_CLASSIFY.c
+++ b/net/ipv4/netfilter/ipt_CLASSIFY.c
@@ -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;
 }
diff --git a/net/ipv4/netfilter/ipt_CONNMARK.c b/net/ipv4/netfilter/ipt_CONNMARK.c
index 8ed744157b1a..134638021339 100644
--- a/net/ipv4/netfilter/ipt_CONNMARK.c
+++ b/net/ipv4/netfilter/ipt_CONNMARK.c
@@ -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;
             }
         }
diff --git a/net/ipv4/netfilter/ipt_DSCP.c b/net/ipv4/netfilter/ipt_DSCP.c
index 3ea4509099f9..975476fef27a 100644
--- a/net/ipv4/netfilter/ipt_DSCP.c
+++ b/net/ipv4/netfilter/ipt_DSCP.c
@@ -51,7 +51,6 @@ target(struct sk_buff **pskb,
                                                  sizeof(diffs),
                                                  (*pskb)->nh.iph->check
                                                  ^ 0xFFFF));
-                (*pskb)->nfcache |= NFC_ALTERED;
         }
         return IPT_CONTINUE;
 }
diff --git a/net/ipv4/netfilter/ipt_ECN.c b/net/ipv4/netfilter/ipt_ECN.c
index 94a0ce1c1c9d..f63a9bc0e4d2 100644
--- a/net/ipv4/netfilter/ipt_ECN.c
+++ b/net/ipv4/netfilter/ipt_ECN.c
@@ -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;
 }
 
diff --git a/net/ipv4/netfilter/ipt_MARK.c b/net/ipv4/netfilter/ipt_MARK.c
index 8526398346cf..52b4f2c296bf 100644
--- a/net/ipv4/netfilter/ipt_MARK.c
+++ b/net/ipv4/netfilter/ipt_MARK.c
@@ -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;
 }
 
diff --git a/net/ipv4/netfilter/ipt_REJECT.c b/net/ipv4/netfilter/ipt_REJECT.c
index 915696446020..f115a84a4ac6 100644
--- a/net/ipv4/netfilter/ipt_REJECT.c
+++ b/net/ipv4/netfilter/ipt_REJECT.c
@@ -156,7 +156,6 @@ static void send_reset(struct sk_buff *oldskb, int hook)
 
         /* This packet will not be the same as the other: clear nf fields */
         nf_reset(nskb);
-        nskb->nfcache = 0;
         nskb->nfmark = 0;
 #ifdef CONFIG_BRIDGE_NETFILTER
         nf_bridge_put(nskb->nf_bridge);
diff --git a/net/ipv4/netfilter/ipt_TCPMSS.c b/net/ipv4/netfilter/ipt_TCPMSS.c
index 7b84a254440e..949288319ca8 100644
--- a/net/ipv4/netfilter/ipt_TCPMSS.c
+++ b/net/ipv4/netfilter/ipt_TCPMSS.c
@@ -190,7 +190,6 @@ ipt_tcpmss_target(struct sk_buff **pskb,
                newmss);
 
  retmodified:
-        (*pskb)->nfcache |= NFC_UNKNOWN | NFC_ALTERED;
         return IPT_CONTINUE;
 }
 
diff --git a/net/ipv4/netfilter/ipt_TOS.c b/net/ipv4/netfilter/ipt_TOS.c
index 85c70d240f8b..49abb7eef0a4 100644
--- a/net/ipv4/netfilter/ipt_TOS.c
+++ b/net/ipv4/netfilter/ipt_TOS.c
@@ -46,7 +46,6 @@ target(struct sk_buff **pskb,
                                                  sizeof(diffs),
                                                  (*pskb)->nh.iph->check
                                                  ^0xFFFF));
-                (*pskb)->nfcache |= NFC_ALTERED;
         }
         return IPT_CONTINUE;
 }
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index ae652ca14bc9..590d2b797197 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -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())
diff --git a/net/ipv6/netfilter/ip6_queue.c b/net/ipv6/netfilter/ip6_queue.c
index a16df5b27c84..83ccedceed17 100644
--- a/net/ipv6/netfilter/ip6_queue.c
+++ b/net/ipv6/netfilter/ip6_queue.c
@@ -388,7 +388,6 @@ ipq_mangle_ipv6(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
diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c
index 73034511c8db..41a67cf6e33a 100644
--- a/net/ipv6/netfilter/ip6_tables.c
+++ b/net/ipv6/netfilter/ip6_tables.c
@@ -401,7 +401,6 @@ ip6t_do_table(struct sk_buff **pskb,
         do {
                 IP_NF_ASSERT(e);
                 IP_NF_ASSERT(back);
-                (*pskb)->nfcache |= e->nfcache;
                 if (ip6_packet_match(*pskb, indev, outdev, &e->ipv6,
                         &protoff, &offset)) {
                         struct ip6t_entry_target *t;
diff --git a/net/ipv6/netfilter/ip6t_MARK.c b/net/ipv6/netfilter/ip6t_MARK.c
index d09ceb05013a..81924fcc5857 100644
--- a/net/ipv6/netfilter/ip6t_MARK.c
+++ b/net/ipv6/netfilter/ip6t_MARK.c
@@ -28,10 +28,9 @@ target(struct sk_buff **pskb,
 {
         const struct ip6t_mark_target_info *markinfo = targinfo;
 
-        if((*pskb)->nfmark != markinfo->mark) {
+        if((*pskb)->nfmark != markinfo->mark)
                 (*pskb)->nfmark = markinfo->mark;
-                (*pskb)->nfcache |= NFC_ALTERED;
-        }
+
         return IP6T_CONTINUE;
 }