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 #define NF_CT_HELPER_NAME_LEN   16
  18
  19 struct nf_conntrack_helper {
  20         struct hlist_node hnode;        /* Internal use. */
  21
  22         const char *name;               /* name of the module */
  23         struct module *me;              /* pointer to self */
  24         const struct nf_conntrack_expect_policy *expect_policy;
  25
  26         /* Tuple of things we will help (compared against server response) */
  27         struct nf_conntrack_tuple tuple;
  28
  29         /* Function to call when data passes; return verdict, or -1 to
  30            invalidate. */
  31         int (*help)(struct sk_buff *skb,
  32                     unsigned int protoff,
  33                     struct nf_conn *ct,
  34                     enum ip_conntrack_info conntrackinfo);
  35
  36         void (*destroy)(struct nf_conn *ct);
  37
  38         int (*to_nlattr)(struct sk_buff *skb, const struct nf_conn *ct);
  39         unsigned int expect_class_max;
  40 };
  41
  42 extern struct nf_conntrack_helper *
  43 __nf_conntrack_helper_find(const char *name, u16 l3num, u8 protonum);
  44
  45 extern struct nf_conntrack_helper *
  46 nf_conntrack_helper_try_module_get(const char *name, u16 l3num, u8 protonum);
  47
  48 extern int nf_conntrack_helper_register(struct nf_conntrack_helper *);
  49 extern void nf_conntrack_helper_unregister(struct nf_conntrack_helper *);
  50
  51 extern struct nf_conn_help *nf_ct_helper_ext_add(struct nf_conn *ct, gfp_t gfp);
  52
  53 extern int __nf_ct_try_assign_helper(struct nf_conn *ct, struct nf_conn *tmpl,
  54                                      gfp_t flags);
  55
  56 extern void nf_ct_helper_destroy(struct nf_conn *ct);
  57
  58 static inline struct nf_conn_help *nfct_help(const struct nf_conn *ct)
  59 {
  60         return nf_ct_ext_find(ct, NF_CT_EXT_HELPER);
  61 }
  62
  63 extern int nf_conntrack_helper_init(struct net *net);
  64 extern void nf_conntrack_helper_fini(struct net *net);
  65
  66 extern int nf_conntrack_broadcast_help(struct sk_buff *skb,
  67                                        unsigned int protoff,
  68                                        struct nf_conn *ct,
  69                                        enum ip_conntrack_info ctinfo,
  70                                        unsigned int timeout);
  71
  72 struct nf_ct_helper_expectfn {
  73         struct list_head head;
  74         const char *name;
  75         void (*expectfn)(struct nf_conn *ct, struct nf_conntrack_expect *exp);
  76 };
  77
  78 void nf_ct_helper_expectfn_register(struct nf_ct_helper_expectfn *n);
  79 void nf_ct_helper_expectfn_unregister(struct nf_ct_helper_expectfn *n);
  80 struct nf_ct_helper_expectfn *
  81 nf_ct_helper_expectfn_find_by_name(const char *name);
  82 struct nf_ct_helper_expectfn *
  83 nf_ct_helper_expectfn_find_by_symbol(const void *symbol);
  84
  85 #endif /*_NF_CONNTRACK_HELPER_H*/