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 #include <net/netfilter/nf_conntrack_expect.h>
  15
  16 struct module;
  17
  18 enum nf_ct_helper_flags {
  19         NF_CT_HELPER_F_USERSPACE        = (1 << 0),
  20         NF_CT_HELPER_F_CONFIGURED       = (1 << 1),
  21 };
  22
  23 #define NF_CT_HELPER_NAME_LEN   16
  24
  25 struct nf_conntrack_helper {
  26         struct hlist_node hnode;        /* Internal use. */
  27
  28         char name[NF_CT_HELPER_NAME_LEN]; /* name of the module */
  29         struct module *me;              /* pointer to self */
  30         const struct nf_conntrack_expect_policy *expect_policy;
  31
  32         /* length of internal data, ie. sizeof(struct nf_ct_*_master) */
  33         size_t data_len;
  34
  35         /* Tuple of things we will help (compared against server response) */
  36         struct nf_conntrack_tuple tuple;
  37
  38         /* Function to call when data passes; return verdict, or -1 to
  39            invalidate. */
  40         int (*help)(struct sk_buff *skb,
  41                     unsigned int protoff,
  42                     struct nf_conn *ct,
  43                     enum ip_conntrack_info conntrackinfo);
  44
  45         void (*destroy)(struct nf_conn *ct);
  46
  47         int (*from_nlattr)(struct nlattr *attr, struct nf_conn *ct);
  48         int (*to_nlattr)(struct sk_buff *skb, const struct nf_conn *ct);
  49         unsigned int expect_class_max;
  50
  51         unsigned int flags;
  52         unsigned int queue_num;         /* For user-space helpers. */
  53 };
  54
  55 /* Must be kept in sync with the classes defined by helpers */
  56 #define NF_CT_MAX_EXPECT_CLASSES        4
  57
  58 /* nf_conn feature for connections that have a helper */
  59 struct nf_conn_help {
  60         /* Helper. if any */
  61         struct nf_conntrack_helper __rcu *helper;
  62
  63         struct hlist_head expectations;
  64
  65         /* Current number of expected connections */
  66         u8 expecting[NF_CT_MAX_EXPECT_CLASSES];
  67
  68         /* private helper information. */
  69         char data[];
  70 };
  71
  72 struct nf_conntrack_helper *__nf_conntrack_helper_find(const char *name,
  73                                                        u16 l3num, u8 protonum);
  74
  75 struct nf_conntrack_helper *nf_conntrack_helper_try_module_get(const char *name,
  76                                                                u16 l3num,
  77                                                                u8 protonum);
  78 void nf_ct_helper_init(struct nf_conntrack_helper *helper,
  79                        u16 l3num, u16 protonum, const char *name,
  80                        u16 default_port, u16 spec_port, u32 id,
  81                        const struct nf_conntrack_expect_policy *exp_pol,
  82                        u32 expect_class_max, u32 data_len,
  83                        int (*help)(struct sk_buff *skb, unsigned int protoff,
  84                                    struct nf_conn *ct,
  85                                    enum ip_conntrack_info ctinfo),
  86                        int (*from_nlattr)(struct nlattr *attr,
  87                                           struct nf_conn *ct),
  88                        struct module *module);
  89
  90 int nf_conntrack_helper_register(struct nf_conntrack_helper *);
  91 void nf_conntrack_helper_unregister(struct nf_conntrack_helper *);
  92
  93 int nf_conntrack_helpers_register(struct nf_conntrack_helper *, unsigned int);
  94 void nf_conntrack_helpers_unregister(struct nf_conntrack_helper *,
  95                                      unsigned int);
  96
  97 struct nf_conn_help *nf_ct_helper_ext_add(struct nf_conn *ct,
  98                                           struct nf_conntrack_helper *helper,
  99                                           gfp_t gfp);
 100
 101 int __nf_ct_try_assign_helper(struct nf_conn *ct, struct nf_conn *tmpl,
 102                               gfp_t flags);
 103
 104 void nf_ct_helper_destroy(struct nf_conn *ct);
 105
 106 static inline struct nf_conn_help *nfct_help(const struct nf_conn *ct)
 107 {
 108         return nf_ct_ext_find(ct, NF_CT_EXT_HELPER);
 109 }
 110
 111 static inline void *nfct_help_data(const struct nf_conn *ct)
 112 {
 113         struct nf_conn_help *help;
 114
 115         help = nf_ct_ext_find(ct, NF_CT_EXT_HELPER);
 116
 117         return (void *)help->data;
 118 }
 119
 120 int nf_conntrack_helper_pernet_init(struct net *net);
 121 void nf_conntrack_helper_pernet_fini(struct net *net);
 122
 123 int nf_conntrack_helper_init(void);
 124 void nf_conntrack_helper_fini(void);
 125
 126 int nf_conntrack_broadcast_help(struct sk_buff *skb, unsigned int protoff,
 127                                 struct nf_conn *ct,
 128                                 enum ip_conntrack_info ctinfo,
 129                                 unsigned int timeout);
 130
 131 struct nf_ct_helper_expectfn {
 132         struct list_head head;
 133         const char *name;
 134         void (*expectfn)(struct nf_conn *ct, struct nf_conntrack_expect *exp);
 135 };
 136
 137 __printf(3,4)
 138 void nf_ct_helper_log(struct sk_buff *skb, const struct nf_conn *ct,
 139                       const char *fmt, ...);
 140
 141 void nf_ct_helper_expectfn_register(struct nf_ct_helper_expectfn *n);
 142 void nf_ct_helper_expectfn_unregister(struct nf_ct_helper_expectfn *n);
 143 struct nf_ct_helper_expectfn *
 144 nf_ct_helper_expectfn_find_by_name(const char *name);
 145 struct nf_ct_helper_expectfn *
 146 nf_ct_helper_expectfn_find_by_symbol(const void *symbol);
 147
 148 extern struct hlist_head *nf_ct_helper_hash;
 149 extern unsigned int nf_ct_helper_hsize;
 150
 151 #endif /*_NF_CONNTRACK_HELPER_H*/