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/netlink.h>
15 #include <net/netlink.h>
16 #include <linux/seq_file.h>
17 #include <net/netfilter/nf_conntrack.h>
18
19 struct nf_conntrack_l3proto {
20 /* L3 Protocol Family number. ex) PF_INET */
21 u_int16_t l3proto;
22
23 /* Protocol name */
24 const char *name;
25
26 /*
27 * Try to fill in the third arg: nhoff is offset of l3 proto
28 * hdr. Return true if possible.
29 */
30 bool (*pkt_to_tuple)(const struct sk_buff *skb, unsigned int nhoff,
31 struct nf_conntrack_tuple *tuple);
32
33 /*
34 * Invert the per-proto part of the tuple: ie. turn xmit into reply.
35 * Some packets can't be inverted: return 0 in that case.
36 */
37 bool (*invert_tuple)(struct nf_conntrack_tuple *inverse,
38 const struct nf_conntrack_tuple *orig);
39
40 /* Print out the per-protocol part of the tuple. */
41 int (*print_tuple)(struct seq_file *s,
42 const struct nf_conntrack_tuple *);
43
44 /*
45 * Called before tracking.
46 * *dataoff: offset of protocol header (TCP, UDP,...) in skb
47 * *protonum: protocol number
48 */
49 int (*get_l4proto)(const struct sk_buff *skb, unsigned int nhoff,
50 unsigned int *dataoff, u_int8_t *protonum);
51
52 int (*tuple_to_nlattr)(struct sk_buff *skb,
53 const struct nf_conntrack_tuple *t);
54
55 /*
56 * Calculate size of tuple nlattr
57 */
58 int (*nlattr_tuple_size)(void);
59
60 int (*nlattr_to_tuple)(struct nlattr *tb[],
61 struct nf_conntrack_tuple *t);
62 const struct nla_policy *nla_policy;
63
64 size_t nla_size;
65
66 #ifdef CONFIG_SYSCTL
67 struct ctl_table_header *ctl_table_header;
68 struct ctl_path *ctl_table_path;
69 struct ctl_table *ctl_table;
70 #endif /* CONFIG_SYSCTL */
71
72 /* Module (if any) which this is connected to. */
73 struct module *me;
74 };
75
76 extern struct nf_conntrack_l3proto __rcu *nf_ct_l3protos[AF_MAX];
77
78 /* Protocol registration. */
79 extern int nf_conntrack_l3proto_register(struct nf_conntrack_l3proto *proto);
80 extern void nf_conntrack_l3proto_unregister(struct nf_conntrack_l3proto *proto);
81 extern struct nf_conntrack_l3proto *nf_ct_l3proto_find_get(u_int16_t l3proto);
82 extern void nf_ct_l3proto_put(struct nf_conntrack_l3proto *p);
83
84 /* Existing built-in protocols */
85 extern struct nf_conntrack_l3proto nf_conntrack_l3proto_generic;
86
87 static inline struct nf_conntrack_l3proto *
__nf_ct_l3proto_find(u_int16_t l3proto)88 __nf_ct_l3proto_find(u_int16_t l3proto)
89 {
90 if (unlikely(l3proto >= AF_MAX))
91 return &nf_conntrack_l3proto_generic;
92 return rcu_dereference(nf_ct_l3protos[l3proto]);
93 }
94
95 #endif /*_NF_CONNTRACK_L3PROTO_H*/
96