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 <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>
19 enum nf_ct_helper_flags {
20 NF_CT_HELPER_F_USERSPACE = (1 << 0),
21 NF_CT_HELPER_F_CONFIGURED = (1 << 1),
24 #define NF_CT_HELPER_NAME_LEN 16
26 struct nf_conntrack_helper {
27 struct hlist_node hnode; /* Internal use. */
29 char name[NF_CT_HELPER_NAME_LEN]; /* name of the module */
31 struct module *me; /* pointer to self */
32 const struct nf_conntrack_expect_policy *expect_policy;
34 /* Tuple of things we will help (compared against server response) */
35 struct nf_conntrack_tuple tuple;
37 /* Function to call when data passes; return verdict, or -1 to
39 int (*help)(struct sk_buff *skb,
42 enum ip_conntrack_info conntrackinfo);
44 void (*destroy)(struct nf_conn *ct);
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;
52 /* For user-space helpers: */
53 unsigned int queue_num;
54 /* length of userspace private data stored in nf_conn_help->data */
58 /* Must be kept in sync with the classes defined by helpers */
59 #define NF_CT_MAX_EXPECT_CLASSES 4
61 /* nf_conn feature for connections that have a helper */
64 struct nf_conntrack_helper __rcu *helper;
66 struct hlist_head expectations;
68 /* Current number of expected connections */
69 u8 expecting[NF_CT_MAX_EXPECT_CLASSES];
71 /* private helper information. */
72 char data[32] __aligned(8);
75 #define NF_CT_HELPER_BUILD_BUG_ON(structsize) \
76 BUILD_BUG_ON((structsize) > FIELD_SIZEOF(struct nf_conn_help, data))
78 struct nf_conntrack_helper *__nf_conntrack_helper_find(const char *name,
79 u16 l3num, u8 protonum);
81 struct nf_conntrack_helper *nf_conntrack_helper_try_module_get(const char *name,
84 void nf_conntrack_helper_put(struct nf_conntrack_helper *helper);
86 void 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,
91 int (*help)(struct sk_buff *skb, unsigned int protoff,
93 enum ip_conntrack_info ctinfo),
94 int (*from_nlattr)(struct nlattr *attr,
96 struct module *module);
98 int nf_conntrack_helper_register(struct nf_conntrack_helper *);
99 void nf_conntrack_helper_unregister(struct nf_conntrack_helper *);
101 int nf_conntrack_helpers_register(struct nf_conntrack_helper *, unsigned int);
102 void nf_conntrack_helpers_unregister(struct nf_conntrack_helper *,
105 struct nf_conn_help *nf_ct_helper_ext_add(struct nf_conn *ct,
106 struct nf_conntrack_helper *helper,
109 int __nf_ct_try_assign_helper(struct nf_conn *ct, struct nf_conn *tmpl,
112 void nf_ct_helper_destroy(struct nf_conn *ct);
114 static inline struct nf_conn_help *nfct_help(const struct nf_conn *ct)
116 return nf_ct_ext_find(ct, NF_CT_EXT_HELPER);
119 static inline void *nfct_help_data(const struct nf_conn *ct)
121 struct nf_conn_help *help;
123 help = nf_ct_ext_find(ct, NF_CT_EXT_HELPER);
125 return (void *)help->data;
128 int nf_conntrack_helper_pernet_init(struct net *net);
129 void nf_conntrack_helper_pernet_fini(struct net *net);
131 int nf_conntrack_helper_init(void);
132 void nf_conntrack_helper_fini(void);
134 int nf_conntrack_broadcast_help(struct sk_buff *skb, unsigned int protoff,
136 enum ip_conntrack_info ctinfo,
137 unsigned int timeout);
139 struct nf_ct_helper_expectfn {
140 struct list_head head;
142 void (*expectfn)(struct nf_conn *ct, struct nf_conntrack_expect *exp);
146 void nf_ct_helper_log(struct sk_buff *skb, const struct nf_conn *ct,
147 const char *fmt, ...);
149 void nf_ct_helper_expectfn_register(struct nf_ct_helper_expectfn *n);
150 void nf_ct_helper_expectfn_unregister(struct nf_ct_helper_expectfn *n);
151 struct nf_ct_helper_expectfn *
152 nf_ct_helper_expectfn_find_by_name(const char *name);
153 struct nf_ct_helper_expectfn *
154 nf_ct_helper_expectfn_find_by_symbol(const void *symbol);
156 extern struct hlist_head *nf_ct_helper_hash;
157 extern unsigned int nf_ct_helper_hsize;
159 #endif /*_NF_CONNTRACK_HELPER_H*/