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         const struct nf_conntrack_expect_policy *expect_policy;
  24
  25         /* Tuple of things we will help (compared against server response) */
  26         struct nf_conntrack_tuple tuple;
  27
  28         /* Function to call when data passes; return verdict, or -1 to
  29            invalidate. */
  30         int (*help)(struct sk_buff *skb,
  31                     unsigned int protoff,
  32                     struct nf_conn *ct,
  33                     enum ip_conntrack_info conntrackinfo);
  34
  35         void (*destroy)(struct nf_conn *ct);
  36
  37         int (*to_nlattr)(struct sk_buff *skb, const struct nf_conn *ct);
  38         unsigned int expect_class_max;
  39 };
  40
  41 extern struct nf_conntrack_helper *
  42 __nf_conntrack_helper_find_byname(const char *name);
  43
  44 extern int nf_conntrack_helper_register(struct nf_conntrack_helper *);
  45 extern void nf_conntrack_helper_unregister(struct nf_conntrack_helper *);
  46
  47 extern struct nf_conn_help *nf_ct_helper_ext_add(struct nf_conn *ct, gfp_t gfp);
  48
  49 extern int __nf_ct_try_assign_helper(struct nf_conn *ct, gfp_t flags);
  50
  51 static inline struct nf_conn_help *nfct_help(const struct nf_conn *ct)
  52 {
  53         return nf_ct_ext_find(ct, NF_CT_EXT_HELPER);
  54 }
  55
  56 extern int nf_conntrack_helper_init(void);
  57 extern void nf_conntrack_helper_fini(void);
  58
  59 #endif /*_NF_CONNTRACK_HELPER_H*/