[NETFILTER] nf_conntrack: clean up to reduce size of 'struct nf_conn'

This patch moves all helper related data fields of 'struct nf_conn'
into a separate structure 'struct nf_conn_help'.  This new structure
is only present in conntrack entries for which we actually have a
helper loaded.

Also, this patch cleans up the nf_conntrack 'features' mechanism to
resemble what the original idea was: Just glue the feature-specific
data structures at the end of 'struct nf_conn', and explicitly
re-calculate the pointer to it when needed rather than keeping
pointers around.

Saves 20 bytes per conntrack on my x86_64 box. A non-helped conntrack
is 276 bytes. We still need to save another 20 bytes in order to fit
into to target of 256bytes.

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

1 files changed, 22 insertions, 17 deletions

diff --git a/net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c b/net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c
index ac702a29dd16..ac35f9526368 100644
--- a/net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c
+++ b/net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c
@@ -179,31 +179,36 @@ static unsigned int ipv6_confirm(unsigned int hooknum,
                                  int (*okfn)(struct sk_buff *))
 {
         struct nf_conn *ct;
+        struct nf_conn_help *help;
         enum ip_conntrack_info ctinfo;
+        unsigned int ret, protoff;
+        unsigned int extoff = (u8*)((*pskb)->nh.ipv6h + 1)
+                              - (*pskb)->data;
+        unsigned char pnum = (*pskb)->nh.ipv6h->nexthdr;
+
 
         /* This is where we call the helper: as the packet goes out. */
         ct = nf_ct_get(*pskb, &ctinfo);
-        if (ct && ct->helper) {
-                unsigned int ret, protoff;
-                unsigned int extoff = (u8*)((*pskb)->nh.ipv6h + 1)
-                                      - (*pskb)->data;
-                unsigned char pnum = (*pskb)->nh.ipv6h->nexthdr;
-
-                protoff = nf_ct_ipv6_skip_exthdr(*pskb, extoff, &pnum,
-                                                 (*pskb)->len - extoff);
-                if (protoff < 0 || protoff > (*pskb)->len ||
-                    pnum == NEXTHDR_FRAGMENT) {
-                        DEBUGP("proto header not found\n");
-                        return NF_ACCEPT;
-                }
+        if (!ct)
+                goto out;
 
-                ret = ct->helper->help(pskb, protoff, ct, ctinfo);
-                if (ret != NF_ACCEPT)
-                        return ret;
+        help = nfct_help(ct);
+        if (!help || !help->helper)
+                goto out;
+
+        protoff = nf_ct_ipv6_skip_exthdr(*pskb, extoff, &pnum,
+                                         (*pskb)->len - extoff);
+        if (protoff < 0 || protoff > (*pskb)->len ||
+            pnum == NEXTHDR_FRAGMENT) {
+                DEBUGP("proto header not found\n");
+                return NF_ACCEPT;
         }
 
+        ret = help->helper->help(pskb, protoff, ct, ctinfo);
+        if (ret != NF_ACCEPT)
+                return ret;
+out:
         /* We've seen it coming out the other side: confirm it */
-
         return nf_conntrack_confirm(pskb);
 }