[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);
 }