LXR linux/include/net/netfilter/nf_conntrack

   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 <linux/refcount.h>
  13#include <net/netfilter/nf_conntrack.h>
  14#include <net/netfilter/nf_conntrack_extend.h>
  15#include <net/netfilter/nf_conntrack_expect.h>
  16
  17struct module;
  18
  19enum nf_ct_helper_flags {
  20        NF_CT_HELPER_F_USERSPACE        = (1 << 0),
  21        NF_CT_HELPER_F_CONFIGURED       = (1 << 1),
  22};
  23
  24#define NF_CT_HELPER_NAME_LEN   16
  25
  26struct nf_conntrack_helper {
  27        struct hlist_node hnode;        /* Internal use. */
  28
  29        char name[NF_CT_HELPER_NAME_LEN]; /* name of the module */
  30        refcount_t refcnt;
  31        struct module *me;              /* pointer to self */
  32        const struct nf_conntrack_expect_policy *expect_policy;
  33
  34        /* Tuple of things we will help (compared against server response) */
  35        struct nf_conntrack_tuple tuple;
  36
  37        /* Function to call when data passes; return verdict, or -1 to
  38           invalidate. */
  39        int (*help)(struct sk_buff *skb,
  40                    unsigned int protoff,
  41                    struct nf_conn *ct,
  42                    enum ip_conntrack_info conntrackinfo);
  43
  44        void (*destroy)(struct nf_conn *ct);
  45
  46        int (*from_nlattr)(struct nlattr *attr, struct nf_conn *ct);
  47        int (*to_nlattr)(struct sk_buff *skb, const struct nf_conn *ct);
  48        unsigned int expect_class_max;
  49
  50        unsigned int flags;
  51
  52        /* For user-space helpers: */
  53        unsigned int queue_num;
  54        /* length of userspace private data stored in nf_conn_help->data */
  55        u16 data_len;
  56};
  57
  58/* Must be kept in sync with the classes defined by helpers */
  59#define NF_CT_MAX_EXPECT_CLASSES        4
  60
  61/* nf_conn feature for connections that have a helper */
  62struct nf_conn_help {
  63        /* Helper. if any */
  64        struct nf_conntrack_helper __rcu *helper;
  65
  66        struct hlist_head expectations;
  67
  68        /* Current number of expected connections */
  69        u8 expecting[NF_CT_MAX_EXPECT_CLASSES];
  70
  71        /* private helper information. */
  72        char data[32] __aligned(8);
  73};
  74
  75#define NF_CT_HELPER_BUILD_BUG_ON(structsize) \
  76        BUILD_BUG_ON((structsize) > FIELD_SIZEOF(struct nf_conn_help, data))
  77
  78struct nf_conntrack_helper *__nf_conntrack_helper_find(const char *name,
  79                                                       u16 l3num, u8 protonum);
  80
  81struct nf_conntrack_helper *nf_conntrack_helper_try_module_get(const char *name,
  82                                                               u16 l3num,
  83                                                               u8 protonum);
  84void nf_conntrack_helper_put(struct nf_conntrack_helper *helper);
  85
  86void nf_ct_helper_init(struct nf_conntrack_helper *helper,
  87                       u16 l3num, u16 protonum, const char *name,
  88                       u16 default_port, u16 spec_port, u32 id,
  89                       const struct nf_conntrack_expect_policy *exp_pol,
  90                       u32 expect_class_max,
  91                       int (*help)(struct sk_buff *skb, unsigned int protoff,
  92                                   struct nf_conn *ct,
  93                                   enum ip_conntrack_info ctinfo),
  94                       int (*from_nlattr)(struct nlattr *attr,
  95                                          struct nf_conn *ct),
  96                       struct module *module);
  97
  98int nf_conntrack_helper_register(struct nf_conntrack_helper *);
  99void nf_conntrack_helper_unregister(struct nf_conntrack_helper *);
 100
 101int nf_conntrack_helpers_register(struct nf_conntrack_helper *, unsigned int);
 102void nf_conntrack_helpers_unregister(struct nf_conntrack_helper *,
 103                                     unsigned int);
 104
 105struct nf_conn_help *nf_ct_helper_ext_add(struct nf_conn *ct,
 106                                          struct nf_conntrack_helper *helper,
 107                                          gfp_t gfp);
 108
 109int __nf_ct_try_assign_helper(struct nf_conn *ct, struct nf_conn *tmpl,
 110                              gfp_t flags);
 111
 112void nf_ct_helper_destroy(struct nf_conn *ct);
 113
 114static inline struct nf_conn_help *nfct_help(const struct nf_conn *ct)
 115{
 116        return nf_ct_ext_find(ct, NF_CT_EXT_HELPER);
 117}
 118
 119static inline void *nfct_help_data(const struct nf_conn *ct)
 120{
 121        struct nf_conn_help *help;
 122
 123        help = nf_ct_ext_find(ct, NF_CT_EXT_HELPER);
 124
 125        return (void *)help->data;
 126}
 127
 128int nf_conntrack_helper_pernet_init(struct net *net);
 129void nf_conntrack_helper_pernet_fini(struct net *net);
 130
 131int nf_conntrack_helper_init(void);
 132void nf_conntrack_helper_fini(void);
 133
 134int nf_conntrack_broadcast_help(struct sk_buff *skb, unsigned int protoff,
 135                                struct nf_conn *ct,
 136                                enum ip_conntrack_info ctinfo,
 137                                unsigned int timeout);
 138
 139struct nf_ct_helper_expectfn {
 140        struct list_head head;
 141        const char *name;
 142        void (*expectfn)(struct nf_conn *ct, struct nf_conntrack_expect *exp);
 143};
 144
 145__printf(3,4)
 146void nf_ct_helper_log(struct sk_buff *skb, const struct nf_conn *ct,
 147                      const char *fmt, ...);
 148
 149void nf_ct_helper_expectfn_register(struct nf_ct_helper_expectfn *n);
 150void nf_ct_helper_expectfn_unregister(struct nf_ct_helper_expectfn *n);
 151struct nf_ct_helper_expectfn *
 152nf_ct_helper_expectfn_find_by_name(const char *name);
 153struct nf_ct_helper_expectfn *
 154nf_ct_helper_expectfn_find_by_symbol(const void *symbol);
 155
 156extern struct hlist_head *nf_ct_helper_hash;
 157extern unsigned int nf_ct_helper_hsize;
 158
 159#endif /*_NF_CONNTRACK_HELPER_H*/
 160