include/net/netfilter/nf_conntrack_extend.h

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