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 	u8 offset[NF_CT_EXT_NUM];
19 	u8 len;
20 	char data[0];
21 };
22 
23 static inline int nf_ct_ext_exist(const struct nf_conn *ct, u8 id)
24 {
25 	return (ct->ext && ct->ext->offset[id]);
26 }
27 
28 static inline void *__nf_ct_ext_find(const struct nf_conn *ct, u8 id)
29 {
30 	if (!nf_ct_ext_exist(ct, id))
31 		return NULL;
32 
33 	return (void *)ct->ext + ct->ext->offset[id];
34 }
35 #define nf_ct_ext_find(ext, id)	\
36 	((id##_TYPE *)__nf_ct_ext_find((ext), (id)))
37 
38 /* Destroy all relationships */
39 extern void __nf_ct_ext_destroy(struct nf_conn *ct);
40 static inline void nf_ct_ext_destroy(struct nf_conn *ct)
41 {
42 	if (ct->ext)
43 		__nf_ct_ext_destroy(ct);
44 }
45 
46 /* Free operation. If you want to free a object referred from private area,
47  * please implement __nf_ct_ext_free() and call it.
48  */
49 static inline void nf_ct_ext_free(struct nf_conn *ct)
50 {
51 	if (ct->ext)
52 		kfree(ct->ext);
53 }
54 
55 /* Add this type, returns pointer to data or NULL. */
56 void *
57 __nf_ct_ext_add(struct nf_conn *ct, enum nf_ct_ext_id id, gfp_t gfp);
58 #define nf_ct_ext_add(ct, id, gfp) \
59 	((id##_TYPE *)__nf_ct_ext_add((ct), (id), (gfp)))
60 
61 #define NF_CT_EXT_F_PREALLOC	0x0001
62 
63 struct nf_ct_ext_type
64 {
65 	/* Destroys relationships (can be NULL). */
66 	void (*destroy)(struct nf_conn *ct);
67 	/* Called when realloacted (can be NULL).
68 	   Contents has already been moved. */
69 	void (*move)(void *new, void *old);
70 
71 	enum nf_ct_ext_id id;
72 
73 	unsigned int flags;
74 
75 	/* Length and min alignment. */
76 	u8 len;
77 	u8 align;
78 	/* initial size of nf_ct_ext. */
79 	u8 alloc_size;
80 };
81 
82 int nf_ct_extend_register(struct nf_ct_ext_type *type);
83 void nf_ct_extend_unregister(struct nf_ct_ext_type *type);
84 #endif /* _NF_CONNTRACK_EXTEND_H */
85