[NETFILTER]: nf_nat: add helpers for common NAT protocol operations

Add generic ->in_range and ->unique_tuple ops to avoid duplicating them
again and again for future NAT modules and save a few bytes of text:

net/ipv4/netfilter/nf_nat_proto_tcp.c:
  tcp_in_range     |  -62 (removed)
  tcp_unique_tuple | -259 # 271 -> 12, # inlines: 1 -> 0, size inlines: 7 -> 0
 2 functions changed, 321 bytes removed

net/ipv4/netfilter/nf_nat_proto_udp.c:
  udp_in_range     |  -62 (removed)
  udp_unique_tuple | -259 # 271 -> 12, # inlines: 1 -> 0, size inlines: 7 -> 0
 2 functions changed, 321 bytes removed

net/ipv4/netfilter/nf_nat_proto_gre.c:
  gre_in_range |  -62 (removed)
 1 function changed, 62 bytes removed

vmlinux:
 5 functions changed, 704 bytes removed

Signed-off-by: Patrick McHardy <kaber@trash.net>

1 files changed, 11 insertions, 0 deletions

diff --git a/include/net/netfilter/nf_nat_protocol.h b/include/net/netfilter/nf_nat_protocol.h
index 4aa0edbb5b96..fa06f6d0de54 100644
--- a/include/net/netfilter/nf_nat_protocol.h
+++ b/include/net/netfilter/nf_nat_protocol.h
@@ -62,6 +62,17 @@ extern int init_protocols(void) __init;
 extern void cleanup_protocols(void);
 extern const struct nf_nat_protocol *find_nat_proto(u_int16_t protonum);
 
+extern int nf_nat_proto_in_range(const struct nf_conntrack_tuple *tuple,
+                                 enum nf_nat_manip_type maniptype,
+                                 const union nf_conntrack_man_proto *min,
+                                 const union nf_conntrack_man_proto *max);
+
+extern int nf_nat_proto_unique_tuple(struct nf_conntrack_tuple *tuple,
+                                     const struct nf_nat_range *range,
+                                     enum nf_nat_manip_type maniptype,
+                                     const struct nf_conn *ct,
+                                     u_int16_t *rover);
+
 extern int nf_nat_port_range_to_nlattr(struct sk_buff *skb,
                                        const struct nf_nat_range *range);
 extern int nf_nat_port_nlattr_to_range(struct nlattr *tb[],