include/net/netfilter/nf_conntrack_helper.h

   1 /*
   2  * connection tracking helpers.
   3  *
   4  * 16 Dec 2003: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
   5  *      - generalize L3 protocol dependent part.
   6  *
   7  * Derived from include/linux/netfiter_ipv4/ip_conntrack_helper.h
   8  */
   9
  10 #ifndef _NF_CONNTRACK_HELPER_H
  11 #define _NF_CONNTRACK_HELPER_H
  12 #include <net/netfilter/nf_conntrack.h>
  13 #include <net/netfilter/nf_conntrack_extend.h>
  14
  15 struct module;
  16
  17 struct nf_conntrack_helper
  18 {
  19         struct hlist_node hnode;        /* Internal use. */
  20
  21         const char *name;               /* name of the module */
  22         struct module *me;              /* pointer to self */
  23         unsigned int max_expected;      /* Maximum number of concurrent
  24                                          * expected connections */
  25         unsigned int timeout;           /* timeout for expecteds */
  26
  27         /* Tuple of things we will help (compared against server response) */
  28         struct nf_conntrack_tuple tuple;
  29
  30         /* Function to call when data passes; return verdict, or -1 to
  31            invalidate. */
  32         int (*help)(struct sk_buff **pskb,
  33                     unsigned int protoff,
  34                     struct nf_conn *ct,
  35                     enum ip_conntrack_info conntrackinfo);
  36
  37         void (*destroy)(struct nf_conn *ct);
  38
  39         int (*to_nfattr)(struct sk_buff *skb, const struct nf_conn *ct);
  40 };
  41
  42 extern struct nf_conntrack_helper *
  43 __nf_ct_helper_find(const struct nf_conntrack_tuple *tuple);
  44
  45 extern struct nf_conntrack_helper *
  46 nf_ct_helper_find_get( const struct nf_conntrack_tuple *tuple);
  47
  48 extern struct nf_conntrack_helper *
  49 __nf_conntrack_helper_find_byname(const char *name);
  50
  51 extern void nf_ct_helper_put(struct nf_conntrack_helper *helper);
  52 extern int nf_conntrack_helper_register(struct nf_conntrack_helper *);
  53 extern void nf_conntrack_helper_unregister(struct nf_conntrack_helper *);
  54
  55 extern struct nf_conn_help *nf_ct_helper_ext_add(struct nf_conn *ct, gfp_t gfp);
  56
  57 static inline struct nf_conn_help *nfct_help(const struct nf_conn *ct)
  58 {
  59         return nf_ct_ext_find(ct, NF_CT_EXT_HELPER);
  60 }
  61 #endif /*_NF_CONNTRACK_HELPER_H*/