netfilter: conntrack: remove l3->l4 mapping information

l4 protocols are demuxed by l3num, l4num pair.

However, almost all l4 trackers are l3 agnostic.

Only exceptions are:
 - gre, icmp (ipv4 only)
 - icmpv6 (ipv6 only)

This commit gets rid of the l3 mapping, l4 trackers can now be looked up
by their IPPROTO_XXX value alone, which gets rid of the additional l3
indirection.

For icmp, ipcmp6 and gre, add a check on state->pf and
return -NF_ACCEPT in case we're asked to track e.g. icmpv6-in-ipv4,
this seems more fitting than using the generic tracker.

Additionally we can kill the 2nd l4proto definitions that were needed
for v4/v6 split -- they are now the same so we can use single l4proto
struct for each protocol, rather than two.

The EXPORT_SYMBOLs can be removed as all these object files are
part of nf_conntrack with no external references.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 7 insertions, 8 deletions

diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index 087bf63826fb..ca1168d67fac 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -379,7 +379,7 @@ bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff,
 		return false;
 	}
 
-	l4proto = __nf_ct_l4proto_find(l3num, protonum);
+	l4proto = __nf_ct_l4proto_find(protonum);
 
 	ret = nf_ct_get_tuple(skb, nhoff, protoff, l3num, protonum, net, tuple,
 			      l4proto);
@@ -539,7 +539,7 @@ destroy_conntrack(struct nf_conntrack *nfct)
 		nf_ct_tmpl_free(ct);
 		return;
 	}
-	l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct));
+	l4proto = __nf_ct_l4proto_find(nf_ct_protonum(ct));
 	if (l4proto->destroy)
 		l4proto->destroy(ct);
 
@@ -840,7 +840,7 @@ static int nf_ct_resolve_clash(struct net *net, struct sk_buff *skb,
 	enum ip_conntrack_info oldinfo;
 	struct nf_conn *loser_ct = nf_ct_get(skb, &oldinfo);
 
-	l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct));
+	l4proto = __nf_ct_l4proto_find(nf_ct_protonum(ct));
 	if (l4proto->allow_clash &&
 	    !nf_ct_is_dying(ct) &&
 	    atomic_inc_not_zero(&ct->ct_general.use)) {
@@ -1109,7 +1109,7 @@ static bool gc_worker_can_early_drop(const struct nf_conn *ct)
 	if (!test_bit(IPS_ASSURED_BIT, &ct->status))
 		return true;
 
-	l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct));
+	l4proto = __nf_ct_l4proto_find(nf_ct_protonum(ct));
 	if (l4proto->can_early_drop && l4proto->can_early_drop(ct))
 		return true;
 
@@ -1549,7 +1549,7 @@ nf_conntrack_in(struct sk_buff *skb, const struct nf_hook_state *state)
 		goto out;
 	}
 
-	l4proto = __nf_ct_l4proto_find(state->pf, protonum);
+	l4proto = __nf_ct_l4proto_find(protonum);
 
 	if (protonum == IPPROTO_ICMP || protonum == IPPROTO_ICMPV6) {
 		ret = nf_conntrack_handle_icmp(tmpl, skb, dataoff,
@@ -1618,8 +1618,7 @@ bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
 
 	rcu_read_lock();
 	ret = nf_ct_invert_tuple(inverse, orig,
-				 __nf_ct_l4proto_find(orig->src.l3num,
-						      orig->dst.protonum));
+				 __nf_ct_l4proto_find(orig->dst.protonum));
 	rcu_read_unlock();
 	return ret;
 }
@@ -1776,7 +1775,7 @@ static int nf_conntrack_update(struct net *net, struct sk_buff *skb)
 	if (dataoff <= 0)
 		return -1;
 
-	l4proto = nf_ct_l4proto_find_get(l3num, l4num);
+	l4proto = nf_ct_l4proto_find_get(l4num);
 
 	if (!nf_ct_get_tuple(skb, skb_network_offset(skb), dataoff, l3num,
 			     l4num, net, &tuple, l4proto))