1 #ifndef _NF_CONNTRACK_EXTEND_H
2 #define _NF_CONNTRACK_EXTEND_H
3 
4 #include <linux/slab.h>
5 
6 #include <net/netfilter/nf_conntrack.h>
7 
8 enum nf_ct_ext_id {
9 	NF_CT_EXT_HELPER,
10 	NF_CT_EXT_NAT,
11 	NF_CT_EXT_ACCT,
12 	NF_CT_EXT_ECACHE,
13 	NF_CT_EXT_ZONE,
14 	NF_CT_EXT_NUM,
15 };
16 
17 #define NF_CT_EXT_HELPER_TYPE struct nf_conn_help
18 #define NF_CT_EXT_NAT_TYPE struct nf_conn_nat
19 #define NF_CT_EXT_ACCT_TYPE struct nf_conn_counter
20 #define NF_CT_EXT_ECACHE_TYPE struct nf_conntrack_ecache
21 #define NF_CT_EXT_ZONE_TYPE struct nf_conntrack_zone
22 
23 /* Extensions: optional stuff which isn't permanently in struct. */
24 struct nf_ct_ext {
25 	struct rcu_head rcu;
26 	u8 offset[NF_CT_EXT_NUM];
27 	u8 len;
28 	char data[0];
29 };
30 
31 static inline int nf_ct_ext_exist(const struct nf_conn *ct, u8 id)
32 {
33 	return (ct->ext && ct->ext->offset[id]);
34 }
35 
36 static inline void *__nf_ct_ext_find(const struct nf_conn *ct, u8 id)
37 {
38 	if (!nf_ct_ext_exist(ct, id))
39 		return NULL;
40 
41 	return (void *)ct->ext + ct->ext->offset[id];
42 }
43 #define nf_ct_ext_find(ext, id)	\
44 	((id##_TYPE *)__nf_ct_ext_find((ext), (id)))
45 
46 /* Destroy all relationships */
47 extern void __nf_ct_ext_destroy(struct nf_conn *ct);
48 static inline void nf_ct_ext_destroy(struct nf_conn *ct)
49 {
50 	if (ct->ext)
51 		__nf_ct_ext_destroy(ct);
52 }
53 
54 /* Free operation. If you want to free a object referred from private area,
55  * please implement __nf_ct_ext_free() and call it.
56  */
57 static inline void nf_ct_ext_free(struct nf_conn *ct)
58 {
59 	if (ct->ext)
60 		kfree(ct->ext);
61 }
62 
63 /* Add this type, returns pointer to data or NULL. */
64 void *
65 __nf_ct_ext_add(struct nf_conn *ct, enum nf_ct_ext_id id, gfp_t gfp);
66 #define nf_ct_ext_add(ct, id, gfp) \
67 	((id##_TYPE *)__nf_ct_ext_add((ct), (id), (gfp)))
68 
69 #define NF_CT_EXT_F_PREALLOC	0x0001
70 
71 struct nf_ct_ext_type {
72 	/* Destroys relationships (can be NULL). */
73 	void (*destroy)(struct nf_conn *ct);
74 	/* Called when realloacted (can be NULL).
75 	   Contents has already been moved. */
76 	void (*move)(void *new, void *old);
77 
78 	enum nf_ct_ext_id id;
79 
80 	unsigned int flags;
81 
82 	/* Length and min alignment. */
83 	u8 len;
84 	u8 align;
85 	/* initial size of nf_ct_ext. */
86 	u8 alloc_size;
87 };
88 
89 int nf_ct_extend_register(struct nf_ct_ext_type *type);
90 void nf_ct_extend_unregister(struct nf_ct_ext_type *type);
91 #endif /* _NF_CONNTRACK_EXTEND_H */
92