1 /* SPDX-License-Identifier: GPL-2.0 */
3 * Copyright (C)2003,2004 USAGI/WIDE Project
5 * Header for use in defining a given L3 protocol for connection tracking.
8 * Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
10 * Derived from include/netfilter_ipv4/ip_conntrack_protocol.h
13 #ifndef _NF_CONNTRACK_L3PROTO_H
14 #define _NF_CONNTRACK_L3PROTO_H
15 #include <linux/netlink.h>
16 #include <net/netlink.h>
17 #include <linux/seq_file.h>
18 #include <net/netfilter/nf_conntrack.h>
20 struct nf_conntrack_l3proto {
21 /* L3 Protocol Family number. ex) PF_INET */
24 /* size of tuple nlattr, fills a hole */
28 * Try to fill in the third arg: nhoff is offset of l3 proto
29 * hdr. Return true if possible.
31 bool (*pkt_to_tuple)(const struct sk_buff *skb, unsigned int nhoff,
32 struct nf_conntrack_tuple *tuple);
35 * Invert the per-proto part of the tuple: ie. turn xmit into reply.
36 * Some packets can't be inverted: return 0 in that case.
38 bool (*invert_tuple)(struct nf_conntrack_tuple *inverse,
39 const struct nf_conntrack_tuple *orig);
42 * Called before tracking.
43 * *dataoff: offset of protocol header (TCP, UDP,...) in skb
44 * *protonum: protocol number
46 int (*get_l4proto)(const struct sk_buff *skb, unsigned int nhoff,
47 unsigned int *dataoff, u_int8_t *protonum);
49 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
50 int (*tuple_to_nlattr)(struct sk_buff *skb,
51 const struct nf_conntrack_tuple *t);
52 int (*nlattr_to_tuple)(struct nlattr *tb[],
53 struct nf_conntrack_tuple *t);
54 const struct nla_policy *nla_policy;
57 /* Called when netns wants to use connection tracking */
58 int (*net_ns_get)(struct net *);
59 void (*net_ns_put)(struct net *);
61 /* Module (if any) which this is connected to. */
65 extern struct nf_conntrack_l3proto __rcu *nf_ct_l3protos[NFPROTO_NUMPROTO];
67 /* Protocol global registration. */
68 int nf_ct_l3proto_register(const struct nf_conntrack_l3proto *proto);
69 void nf_ct_l3proto_unregister(const struct nf_conntrack_l3proto *proto);
71 const struct nf_conntrack_l3proto *nf_ct_l3proto_find_get(u_int16_t l3proto);
73 /* Existing built-in protocols */
74 extern struct nf_conntrack_l3proto nf_conntrack_l3proto_generic;
76 static inline struct nf_conntrack_l3proto *
77 __nf_ct_l3proto_find(u_int16_t l3proto)
79 if (unlikely(l3proto >= NFPROTO_NUMPROTO))
80 return &nf_conntrack_l3proto_generic;
81 return rcu_dereference(nf_ct_l3protos[l3proto]);
84 #endif /*_NF_CONNTRACK_L3PROTO_H*/