1 | /* SPDX-License-Identifier: GPL-2.0 */ |
2 | /* |
3 | * connection tracking helpers. |
4 | * |
5 | * 16 Dec 2003: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp> |
6 | * - generalize L3 protocol dependent part. |
7 | * |
8 | * Derived from include/linux/netfiter_ipv4/ip_conntrack_helper.h |
9 | */ |
10 | |
11 | #ifndef _NF_CONNTRACK_HELPER_H |
12 | #define _NF_CONNTRACK_HELPER_H |
13 | #include <linux/refcount.h> |
14 | #include <net/netfilter/nf_conntrack.h> |
15 | #include <net/netfilter/nf_conntrack_extend.h> |
16 | #include <net/netfilter/nf_conntrack_expect.h> |
17 | |
18 | #define NF_NAT_HELPER_PREFIX "ip_nat_" |
19 | #define NF_NAT_HELPER_NAME(name) NF_NAT_HELPER_PREFIX name |
20 | #define MODULE_ALIAS_NF_NAT_HELPER(name) \ |
21 | MODULE_ALIAS(NF_NAT_HELPER_NAME(name)) |
22 | |
23 | struct module; |
24 | |
25 | enum nf_ct_helper_flags { |
26 | NF_CT_HELPER_F_USERSPACE = (1 << 0), |
27 | NF_CT_HELPER_F_CONFIGURED = (1 << 1), |
28 | }; |
29 | |
30 | #define NF_CT_HELPER_NAME_LEN 16 |
31 | |
32 | struct nf_conntrack_helper { |
33 | struct hlist_node hnode; /* Internal use. */ |
34 | |
35 | char name[NF_CT_HELPER_NAME_LEN]; /* name of the module */ |
36 | refcount_t refcnt; |
37 | struct module *me; /* pointer to self */ |
38 | const struct nf_conntrack_expect_policy *expect_policy; |
39 | |
40 | /* Tuple of things we will help (compared against server response) */ |
41 | struct nf_conntrack_tuple tuple; |
42 | |
43 | /* Function to call when data passes; return verdict, or -1 to |
44 | invalidate. */ |
45 | int (*help)(struct sk_buff *skb, |
46 | unsigned int protoff, |
47 | struct nf_conn *ct, |
48 | enum ip_conntrack_info conntrackinfo); |
49 | |
50 | void (*destroy)(struct nf_conn *ct); |
51 | |
52 | int (*from_nlattr)(struct nlattr *attr, struct nf_conn *ct); |
53 | int (*to_nlattr)(struct sk_buff *skb, const struct nf_conn *ct); |
54 | unsigned int expect_class_max; |
55 | |
56 | unsigned int flags; |
57 | |
58 | /* For user-space helpers: */ |
59 | unsigned int queue_num; |
60 | /* length of userspace private data stored in nf_conn_help->data */ |
61 | u16 data_len; |
62 | /* name of NAT helper module */ |
63 | char nat_mod_name[NF_CT_HELPER_NAME_LEN]; |
64 | }; |
65 | |
66 | /* Must be kept in sync with the classes defined by helpers */ |
67 | #define NF_CT_MAX_EXPECT_CLASSES 4 |
68 | |
69 | /* nf_conn feature for connections that have a helper */ |
70 | struct nf_conn_help { |
71 | /* Helper. if any */ |
72 | struct nf_conntrack_helper __rcu *helper; |
73 | |
74 | struct hlist_head expectations; |
75 | |
76 | /* Current number of expected connections */ |
77 | u8 expecting[NF_CT_MAX_EXPECT_CLASSES]; |
78 | |
79 | /* private helper information. */ |
80 | char data[32] __aligned(8); |
81 | }; |
82 | |
83 | #define NF_CT_HELPER_BUILD_BUG_ON(structsize) \ |
84 | BUILD_BUG_ON((structsize) > sizeof_field(struct nf_conn_help, data)) |
85 | |
86 | struct nf_conntrack_helper *__nf_conntrack_helper_find(const char *name, |
87 | u16 l3num, u8 protonum); |
88 | |
89 | struct nf_conntrack_helper *nf_conntrack_helper_try_module_get(const char *name, |
90 | u16 l3num, |
91 | u8 protonum); |
92 | void nf_conntrack_helper_put(struct nf_conntrack_helper *helper); |
93 | |
94 | void nf_ct_helper_init(struct nf_conntrack_helper *helper, |
95 | u16 l3num, u16 protonum, const char *name, |
96 | u16 default_port, u16 spec_port, u32 id, |
97 | const struct nf_conntrack_expect_policy *exp_pol, |
98 | u32 expect_class_max, |
99 | int (*help)(struct sk_buff *skb, unsigned int protoff, |
100 | struct nf_conn *ct, |
101 | enum ip_conntrack_info ctinfo), |
102 | int (*from_nlattr)(struct nlattr *attr, |
103 | struct nf_conn *ct), |
104 | struct module *module); |
105 | |
106 | int nf_conntrack_helper_register(struct nf_conntrack_helper *); |
107 | void nf_conntrack_helper_unregister(struct nf_conntrack_helper *); |
108 | |
109 | int nf_conntrack_helpers_register(struct nf_conntrack_helper *, unsigned int); |
110 | void nf_conntrack_helpers_unregister(struct nf_conntrack_helper *, |
111 | unsigned int); |
112 | |
113 | struct nf_conn_help *nf_ct_helper_ext_add(struct nf_conn *ct, gfp_t gfp); |
114 | |
115 | int __nf_ct_try_assign_helper(struct nf_conn *ct, struct nf_conn *tmpl, |
116 | gfp_t flags); |
117 | |
118 | int nf_ct_helper(struct sk_buff *skb, struct nf_conn *ct, |
119 | enum ip_conntrack_info ctinfo, u16 proto); |
120 | int nf_ct_add_helper(struct nf_conn *ct, const char *name, u8 family, |
121 | u8 proto, bool nat, struct nf_conntrack_helper **hp); |
122 | |
123 | void nf_ct_helper_destroy(struct nf_conn *ct); |
124 | |
125 | static inline struct nf_conn_help *nfct_help(const struct nf_conn *ct) |
126 | { |
127 | return nf_ct_ext_find(ct, id: NF_CT_EXT_HELPER); |
128 | } |
129 | |
130 | static inline void *nfct_help_data(const struct nf_conn *ct) |
131 | { |
132 | struct nf_conn_help *help; |
133 | |
134 | help = nf_ct_ext_find(ct, id: NF_CT_EXT_HELPER); |
135 | |
136 | return (void *)help->data; |
137 | } |
138 | |
139 | int nf_conntrack_helper_init(void); |
140 | void nf_conntrack_helper_fini(void); |
141 | |
142 | int nf_conntrack_broadcast_help(struct sk_buff *skb, struct nf_conn *ct, |
143 | enum ip_conntrack_info ctinfo, |
144 | unsigned int timeout); |
145 | |
146 | struct nf_ct_helper_expectfn { |
147 | struct list_head head; |
148 | const char *name; |
149 | void (*expectfn)(struct nf_conn *ct, struct nf_conntrack_expect *exp); |
150 | }; |
151 | |
152 | __printf(3,4) |
153 | void nf_ct_helper_log(struct sk_buff *skb, const struct nf_conn *ct, |
154 | const char *fmt, ...); |
155 | |
156 | void nf_ct_helper_expectfn_register(struct nf_ct_helper_expectfn *n); |
157 | void nf_ct_helper_expectfn_unregister(struct nf_ct_helper_expectfn *n); |
158 | struct nf_ct_helper_expectfn * |
159 | nf_ct_helper_expectfn_find_by_name(const char *name); |
160 | struct nf_ct_helper_expectfn * |
161 | nf_ct_helper_expectfn_find_by_symbol(const void *symbol); |
162 | |
163 | extern struct hlist_head *nf_ct_helper_hash; |
164 | extern unsigned int nf_ct_helper_hsize; |
165 | |
166 | struct nf_conntrack_nat_helper { |
167 | struct list_head list; |
168 | char mod_name[NF_CT_HELPER_NAME_LEN]; /* module name */ |
169 | struct module *module; /* pointer to self */ |
170 | }; |
171 | |
172 | #define NF_CT_NAT_HELPER_INIT(name) \ |
173 | { \ |
174 | .mod_name = NF_NAT_HELPER_NAME(name), \ |
175 | .module = THIS_MODULE \ |
176 | } |
177 | |
178 | void nf_nat_helper_register(struct nf_conntrack_nat_helper *nat); |
179 | void nf_nat_helper_unregister(struct nf_conntrack_nat_helper *nat); |
180 | int nf_nat_helper_try_module_get(const char *name, u16 l3num, |
181 | u8 protonum); |
182 | void nf_nat_helper_put(struct nf_conntrack_helper *helper); |
183 | #endif /*_NF_CONNTRACK_HELPER_H*/ |
184 | |