netfilter: conntrack: handle icmp pkt_to_tuple helper via direct calls

rather than handling them via indirect call, use a direct one instead.
This leaves GRE as the last user of this indirect call facility.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

include/net/netfilter/nf_conntrack_l4proto.h

@@ -90,6 +90,16 @@ struct nf_conntrack_l4proto {
 	struct module *me;
 };
 
+bool icmp_pkt_to_tuple(const struct sk_buff *skb,
+		       unsigned int dataoff,
+		       struct net *net,
+		       struct nf_conntrack_tuple *tuple);
+
+bool icmpv6_pkt_to_tuple(const struct sk_buff *skb,
+			 unsigned int dataoff,
+			 struct net *net,
+			 struct nf_conntrack_tuple *tuple);
+
 int nf_conntrack_icmpv4_error(struct nf_conn *tmpl,
 			      struct sk_buff *skb,
 			      unsigned int dataoff,

net/netfilter/nf_conntrack_core.c

@@ -274,6 +274,12 @@ nf_ct_get_tuple(const struct sk_buff *skb,
 	tuple->dst.protonum = protonum;
 	tuple->dst.dir = IP_CT_DIR_ORIGINAL;
 
+	switch (protonum) {
+	case IPPROTO_ICMPV6:
+		return icmpv6_pkt_to_tuple(skb, dataoff, net, tuple);
+	case IPPROTO_ICMP:
+		return icmp_pkt_to_tuple(skb, dataoff, net, tuple);
+	}
 	if (unlikely(l4proto->pkt_to_tuple))
 		return l4proto->pkt_to_tuple(skb, dataoff, net, tuple);
 

net/netfilter/nf_conntrack_proto_icmp.c

@@ -25,7 +25,7 @@
 
 static const unsigned int nf_ct_icmp_timeout = 30*HZ;
 
-static bool icmp_pkt_to_tuple(const struct sk_buff *skb, unsigned int dataoff,
+bool icmp_pkt_to_tuple(const struct sk_buff *skb, unsigned int dataoff,
 		       struct net *net, struct nf_conntrack_tuple *tuple)
 {
 	const struct icmphdr *hp;
@@ -347,7 +347,6 @@ static struct nf_proto_net *icmp_get_net_proto(struct net *net)
 const struct nf_conntrack_l4proto nf_conntrack_l4proto_icmp =
 {
 	.l4proto		= IPPROTO_ICMP,
-	.pkt_to_tuple		= icmp_pkt_to_tuple,
 	.invert_tuple		= icmp_invert_tuple,
 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
 	.tuple_to_nlattr	= icmp_tuple_to_nlattr,

net/netfilter/nf_conntrack_proto_icmpv6.c

@@ -30,7 +30,7 @@
 
 static const unsigned int nf_ct_icmpv6_timeout = 30*HZ;
 
-static bool icmpv6_pkt_to_tuple(const struct sk_buff *skb,
+bool icmpv6_pkt_to_tuple(const struct sk_buff *skb,
 			 unsigned int dataoff,
 			 struct net *net,
 			 struct nf_conntrack_tuple *tuple)
@@ -358,7 +358,6 @@ static struct nf_proto_net *icmpv6_get_net_proto(struct net *net)
 const struct nf_conntrack_l4proto nf_conntrack_l4proto_icmpv6 =
 {
 	.l4proto		= IPPROTO_ICMPV6,
-	.pkt_to_tuple		= icmpv6_pkt_to_tuple,
 	.invert_tuple		= icmpv6_invert_tuple,
 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
 	.tuple_to_nlattr	= icmpv6_tuple_to_nlattr,