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         u8 real_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)(struct nf_conn *ct, 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 */