1 /* Header for use in defining a given protocol for connection tracking. */
2 #ifndef _IP_CONNTRACK_PROTOCOL_H
3 #define _IP_CONNTRACK_PROTOCOL_H
4 #include <linux/netfilter_ipv4/ip_conntrack.h>
5 
6 struct ip_conntrack_protocol
7 {
8 	/* Next pointer. */
9 	struct list_head list;
10 
11 	/* Protocol number. */
12 	u_int8_t proto;
13 
14 	/* Protocol name */
15 	const char *name;
16 
17 	/* Try to fill in the third arg; return true if possible. */
18 	int (*pkt_to_tuple)(const void *datah, size_t datalen,
19 			    struct ip_conntrack_tuple *tuple);
20 
21 	/* Invert the per-proto part of the tuple: ie. turn xmit into reply.
22 	 * Some packets can't be inverted: return 0 in that case.
23 	 */
24 	int (*invert_tuple)(struct ip_conntrack_tuple *inverse,
25 			    const struct ip_conntrack_tuple *orig);
26 
27 	/* Print out the per-protocol part of the tuple. */
28 	unsigned int (*print_tuple)(char *buffer,
29 				    const struct ip_conntrack_tuple *);
30 
31 	/* Print out the private part of the conntrack. */
32 	unsigned int (*print_conntrack)(char *buffer,
33 					const struct ip_conntrack *);
34 
35 	/* Returns verdict for packet, or -1 for invalid. */
36 	int (*packet)(struct ip_conntrack *conntrack,
37 		      struct iphdr *iph, size_t len,
38 		      enum ip_conntrack_info ctinfo);
39 
40 	/* Called when a new connection for this protocol found;
41 	 * returns TRUE if it's OK.  If so, packet() called next. */
42 	int (*new)(struct ip_conntrack *conntrack, struct iphdr *iph,
43 		   size_t len);
44 
45 	/* Called when a conntrack entry is destroyed */
46 	void (*destroy)(struct ip_conntrack *conntrack);
47 
48 	/* Has to decide if a expectation matches one packet or not */
49 	int (*exp_matches_pkt)(struct ip_conntrack_expect *exp,
50 			       struct sk_buff **pskb);
51 
52 	/* Module (if any) which this is connected to. */
53 	struct module *me;
54 };
55 
56 /* Protocol registration. */
57 extern int ip_conntrack_protocol_register(struct ip_conntrack_protocol *proto);
58 extern void ip_conntrack_protocol_unregister(struct ip_conntrack_protocol *proto);
59 
60 /* Existing built-in protocols */
61 extern struct ip_conntrack_protocol ip_conntrack_protocol_tcp;
62 extern struct ip_conntrack_protocol ip_conntrack_protocol_udp;
63 extern struct ip_conntrack_protocol ip_conntrack_protocol_icmp;
64 extern int ip_conntrack_protocol_tcp_init(void);
65 #endif /*_IP_CONNTRACK_PROTOCOL_H*/
66