1/*
2 * Copyright (C)2003,2004 USAGI/WIDE Project
3 *
4 * Header for use in defining a given L3 protocol for connection tracking.
5 *
6 * Author:
7 *	Yasuyuki Kozakai @USAGI	<yasuyuki.kozakai@toshiba.co.jp>
8 *
9 * Derived from include/netfilter_ipv4/ip_conntrack_protocol.h
10 */
11
12#ifndef _NF_CONNTRACK_L3PROTO_H
13#define _NF_CONNTRACK_L3PROTO_H
14#include <linux/seq_file.h>
15#include <net/netfilter/nf_conntrack.h>
16
17struct nfattr;
18
19struct nf_conntrack_l3proto
20{
21	/* L3 Protocol Family number. ex) PF_INET */
22	u_int16_t l3proto;
23
24	/* Protocol name */
25	const char *name;
26
27	/*
28	 * Try to fill in the third arg: nhoff is offset of l3 proto
29         * hdr.  Return true if possible.
30	 */
31	int (*pkt_to_tuple)(const struct sk_buff *skb, unsigned int nhoff,
32			    struct nf_conntrack_tuple *tuple);
33
34	/*
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.
37	 */
38	int (*invert_tuple)(struct nf_conntrack_tuple *inverse,
39			    const struct nf_conntrack_tuple *orig);
40
41	/* Print out the per-protocol part of the tuple. */
42	int (*print_tuple)(struct seq_file *s,
43			   const struct nf_conntrack_tuple *);
44
45	/* Print out the private part of the conntrack. */
46	int (*print_conntrack)(struct seq_file *s, const struct nf_conn *);
47
48	/* Returns verdict for packet, or -1 for invalid. */
49	int (*packet)(struct nf_conn *conntrack,
50		      const struct sk_buff *skb,
51		      enum ip_conntrack_info ctinfo);
52
53	/*
54	 * Called when a new connection for this protocol found;
55	 * returns TRUE if it's OK.  If so, packet() called next.
56	 */
57	int (*new)(struct nf_conn *conntrack, const struct sk_buff *skb);
58
59	/*
60	 * Called before tracking.
61	 *	*dataoff: offset of protocol header (TCP, UDP,...) in *pskb
62	 *	*protonum: protocol number
63	 */
64	int (*prepare)(struct sk_buff **pskb, unsigned int hooknum,
65		       unsigned int *dataoff, u_int8_t *protonum);
66
67	u_int32_t (*get_features)(const struct nf_conntrack_tuple *tuple);
68
69	int (*tuple_to_nfattr)(struct sk_buff *skb,
70			       const struct nf_conntrack_tuple *t);
71
72	int (*nfattr_to_tuple)(struct nfattr *tb[],
73			       struct nf_conntrack_tuple *t);
74
75#ifdef CONFIG_SYSCTL
76	struct ctl_table_header	*ctl_table_header;
77	struct ctl_table	*ctl_table_path;
78	struct ctl_table	*ctl_table;
79#endif /* CONFIG_SYSCTL */
80
81	/* Module (if any) which this is connected to. */
82	struct module *me;
83};
84
85extern struct nf_conntrack_l3proto *nf_ct_l3protos[AF_MAX];
86
87/* Protocol registration. */
88extern int nf_conntrack_l3proto_register(struct nf_conntrack_l3proto *proto);
89extern void nf_conntrack_l3proto_unregister(struct nf_conntrack_l3proto *proto);
90extern struct nf_conntrack_l3proto *nf_ct_l3proto_find_get(u_int16_t l3proto);
91extern void nf_ct_l3proto_put(struct nf_conntrack_l3proto *p);
92
93/* Existing built-in protocols */
94extern struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv4;
95extern struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv6;
96extern struct nf_conntrack_l3proto nf_conntrack_l3proto_generic;
97
98static inline struct nf_conntrack_l3proto *
99__nf_ct_l3proto_find(u_int16_t l3proto)
100{
101	if (unlikely(l3proto >= AF_MAX))
102		return &nf_conntrack_l3proto_generic;
103	return rcu_dereference(nf_ct_l3protos[l3proto]);
104}
105
106#endif /*_NF_CONNTRACK_L3PROTO_H*/
107