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_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 */