2 * connection tracking helpers.
4 * 16 Dec 2003: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
5 * - generalize L3 protocol dependent part.
7 * Derived from include/linux/netfiter_ipv4/ip_conntrack_helper.h
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>
18 enum nf_ct_helper_flags {
19 NF_CT_HELPER_F_USERSPACE = (1 << 0),
20 NF_CT_HELPER_F_CONFIGURED = (1 << 1),
23 #define NF_CT_HELPER_NAME_LEN 16
25 struct nf_conntrack_helper {
26 struct hlist_node hnode; /* Internal use. */
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;
32 /* Tuple of things we will help (compared against server response) */
33 struct nf_conntrack_tuple tuple;
35 /* Function to call when data passes; return verdict, or -1 to
37 int (*help)(struct sk_buff *skb,
40 enum ip_conntrack_info conntrackinfo);
42 void (*destroy)(struct nf_conn *ct);
44 int (*from_nlattr)(struct nlattr *attr, struct nf_conn *ct);
45 int (*to_nlattr)(struct sk_buff *skb, const struct nf_conn *ct);
46 unsigned int expect_class_max;
50 /* For user-space helpers: */
51 unsigned int queue_num;
52 /* length of userspace private data stored in nf_conn_help->data */
56 /* Must be kept in sync with the classes defined by helpers */
57 #define NF_CT_MAX_EXPECT_CLASSES 4
59 /* nf_conn feature for connections that have a helper */
62 struct nf_conntrack_helper __rcu *helper;
64 struct hlist_head expectations;
66 /* Current number of expected connections */
67 u8 expecting[NF_CT_MAX_EXPECT_CLASSES];
69 /* private helper information. */
70 char data[32] __aligned(8);
73 #define NF_CT_HELPER_BUILD_BUG_ON(structsize) \
74 BUILD_BUG_ON((structsize) > FIELD_SIZEOF(struct nf_conn_help, data))
76 struct nf_conntrack_helper *__nf_conntrack_helper_find(const char *name,
77 u16 l3num, u8 protonum);
79 struct nf_conntrack_helper *nf_conntrack_helper_try_module_get(const char *name,
82 void nf_ct_helper_init(struct nf_conntrack_helper *helper,
83 u16 l3num, u16 protonum, const char *name,
84 u16 default_port, u16 spec_port, u32 id,
85 const struct nf_conntrack_expect_policy *exp_pol,
87 int (*help)(struct sk_buff *skb, unsigned int protoff,
89 enum ip_conntrack_info ctinfo),
90 int (*from_nlattr)(struct nlattr *attr,
92 struct module *module);
94 int nf_conntrack_helper_register(struct nf_conntrack_helper *);
95 void nf_conntrack_helper_unregister(struct nf_conntrack_helper *);
97 int nf_conntrack_helpers_register(struct nf_conntrack_helper *, unsigned int);
98 void nf_conntrack_helpers_unregister(struct nf_conntrack_helper *,
101 struct nf_conn_help *nf_ct_helper_ext_add(struct nf_conn *ct,
102 struct nf_conntrack_helper *helper,
105 int __nf_ct_try_assign_helper(struct nf_conn *ct, struct nf_conn *tmpl,
108 void nf_ct_helper_destroy(struct nf_conn *ct);
110 static inline struct nf_conn_help *nfct_help(const struct nf_conn *ct)
112 return nf_ct_ext_find(ct, NF_CT_EXT_HELPER);
115 static inline void *nfct_help_data(const struct nf_conn *ct)
117 struct nf_conn_help *help;
119 help = nf_ct_ext_find(ct, NF_CT_EXT_HELPER);
121 return (void *)help->data;
124 int nf_conntrack_helper_pernet_init(struct net *net);
125 void nf_conntrack_helper_pernet_fini(struct net *net);
127 int nf_conntrack_helper_init(void);
128 void nf_conntrack_helper_fini(void);
130 int nf_conntrack_broadcast_help(struct sk_buff *skb, unsigned int protoff,
132 enum ip_conntrack_info ctinfo,
133 unsigned int timeout);
135 struct nf_ct_helper_expectfn {
136 struct list_head head;
138 void (*expectfn)(struct nf_conn *ct, struct nf_conntrack_expect *exp);
142 void nf_ct_helper_log(struct sk_buff *skb, const struct nf_conn *ct,
143 const char *fmt, ...);
145 void nf_ct_helper_expectfn_register(struct nf_ct_helper_expectfn *n);
146 void nf_ct_helper_expectfn_unregister(struct nf_ct_helper_expectfn *n);
147 struct nf_ct_helper_expectfn *
148 nf_ct_helper_expectfn_find_by_name(const char *name);
149 struct nf_ct_helper_expectfn *
150 nf_ct_helper_expectfn_find_by_symbol(const void *symbol);
152 extern struct hlist_head *nf_ct_helper_hash;
153 extern unsigned int nf_ct_helper_hsize;
155 #endif /*_NF_CONNTRACK_HELPER_H*/