netfilter: xtables: move extension arguments into compound structure (1/6)

The function signatures for Xtables extensions have grown over time.
It involves a lot of typing/replication, and also a bit of stack space
even if they are not used. Realize an NFWS2008 idea and pack them into
structs. The skb remains outside of the struct so gcc can continue to
apply its optimizations.

This patch does this for match extensions' match functions.

A few ambiguities have also been addressed. The "offset" parameter for
example has been renamed to "fragoff" (there are so many different
offsets already) and "protoff" to "thoff" (there is more than just one
protocol here, so clarify).

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>

1 files changed, 7 insertions, 10 deletions

diff --git a/net/netfilter/xt_connlimit.c b/net/netfilter/xt_connlimit.c
index bd00830ff697..8b8f70e76646 100644
--- a/net/netfilter/xt_connlimit.c
+++ b/net/netfilter/xt_connlimit.c
@@ -178,12 +178,9 @@ static int count_them(struct xt_connlimit_data *data,
 }
 
 static bool
-connlimit_mt(const struct sk_buff *skb, const struct net_device *in,
-             const struct net_device *out, const struct xt_match *match,
-             const void *matchinfo, int offset, unsigned int protoff,
-             bool *hotdrop)
+connlimit_mt(const struct sk_buff *skb, const struct xt_match_param *par)
 {
-	const struct xt_connlimit_info *info = matchinfo;
+	const struct xt_connlimit_info *info = par->matchinfo;
 	union nf_inet_addr addr;
 	struct nf_conntrack_tuple tuple;
 	const struct nf_conntrack_tuple *tuple_ptr = &tuple;
@@ -195,10 +192,10 @@ connlimit_mt(const struct sk_buff *skb, const struct net_device *in,
 	if (ct != NULL)
 		tuple_ptr = &ct->tuplehash[0].tuple;
 	else if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb),
-				    match->family, &tuple))
+				    par->match->family, &tuple))
 		goto hotdrop;
 
-	if (match->family == NFPROTO_IPV6) {
+	if (par->match->family == NFPROTO_IPV6) {
 		const struct ipv6hdr *iph = ipv6_hdr(skb);
 		memcpy(&addr.ip6, &iph->saddr, sizeof(iph->saddr));
 	} else {
@@ -208,19 +205,19 @@ connlimit_mt(const struct sk_buff *skb, const struct net_device *in,
 
 	spin_lock_bh(&info->data->lock);
 	connections = count_them(info->data, tuple_ptr, &addr,
-	                         &info->mask, match);
+	                         &info->mask, par->match);
 	spin_unlock_bh(&info->data->lock);
 
 	if (connections < 0) {
 		/* kmalloc failed, drop it entirely */
-		*hotdrop = true;
+		*par->hotdrop = true;
 		return false;
 	}
 
 	return (connections > info->limit) ^ info->inverse;
 
  hotdrop:
-	*hotdrop = true;
+	*par->hotdrop = true;
 	return false;
 }