1 #ifndef _NF_CONNTRACK_EXTEND_H
2 #define _NF_CONNTRACK_EXTEND_H
3 
4 #include <net/netfilter/nf_conntrack.h>
5 
6 enum nf_ct_ext_id
7 {
8 	NF_CT_EXT_HELPER,
9 	NF_CT_EXT_NAT,
10 	NF_CT_EXT_NUM,
11 };
12 
13 #define NF_CT_EXT_HELPER_TYPE struct nf_conn_help
14 #define NF_CT_EXT_NAT_TYPE struct nf_conn_nat
15 
16 /* Extensions: optional stuff which isn't permanently in struct. */
17 struct nf_ct_ext {
18 	struct rcu_head rcu;
19 	u8 offset[NF_CT_EXT_NUM];
20 	u8 len;
21 	char data[0];
22 };
23 
24 static inline int nf_ct_ext_exist(const struct nf_conn *ct, u8 id)
25 {
26 	return (ct->ext && ct->ext->offset[id]);
27 }
28 
29 static inline void *__nf_ct_ext_find(const struct nf_conn *ct, u8 id)
30 {
31 	if (!nf_ct_ext_exist(ct, id))
32 		return NULL;
33 
34 	return (void *)ct->ext + ct->ext->offset[id];
35 }
36 #define nf_ct_ext_find(ext, id)	\
37 	((id##_TYPE *)__nf_ct_ext_find((ext), (id)))
38 
39 /* Destroy all relationships */
40 extern void __nf_ct_ext_destroy(struct nf_conn *ct);
41 static inline void nf_ct_ext_destroy(struct nf_conn *ct)
42 {
43 	if (ct->ext)
44 		__nf_ct_ext_destroy(ct);
45 }
46 
47 /* Free operation. If you want to free a object referred from private area,
48  * please implement __nf_ct_ext_free() and call it.
49  */
50 static inline void nf_ct_ext_free(struct nf_conn *ct)
51 {
52 	if (ct->ext)
53 		kfree(ct->ext);
54 }
55 
56 /* Add this type, returns pointer to data or NULL. */
57 void *
58 __nf_ct_ext_add(struct nf_conn *ct, enum nf_ct_ext_id id, gfp_t gfp);
59 #define nf_ct_ext_add(ct, id, gfp) \
60 	((id##_TYPE *)__nf_ct_ext_add((ct), (id), (gfp)))
61 
62 #define NF_CT_EXT_F_PREALLOC	0x0001
63 
64 struct nf_ct_ext_type
65 {
66 	/* Destroys relationships (can be NULL). */
67 	void (*destroy)(struct nf_conn *ct);
68 	/* Called when realloacted (can be NULL).
69 	   Contents has already been moved. */
70 	void (*move)(void *new, void *old);
71 
72 	enum nf_ct_ext_id id;
73 
74 	unsigned int flags;
75 
76 	/* Length and min alignment. */
77 	u8 len;
78 	u8 align;
79 	/* initial size of nf_ct_ext. */
80 	u8 alloc_size;
81 };
82 
83 int nf_ct_extend_register(struct nf_ct_ext_type *type);
84 void nf_ct_extend_unregister(struct nf_ct_ext_type *type);
85 #endif /* _NF_CONNTRACK_EXTEND_H */
86