1 #ifndef __LINUX_NETFILTER_H
2 #define __LINUX_NETFILTER_H
3
4 #ifdef __KERNEL__
5 #include <linux/init.h>
6 #include <linux/skbuff.h>
7 #include <linux/net.h>
8 #include <linux/if.h>
9 #include <linux/in.h>
10 #include <linux/in6.h>
11 #include <linux/wait.h>
12 #include <linux/list.h>
13 #endif
14 #include <linux/types.h>
15 #include <linux/compiler.h>
16
17 /* Responses from hook functions. */
18 #define NF_DROP 0
19 #define NF_ACCEPT 1
20 #define NF_STOLEN 2
21 #define NF_QUEUE 3
22 #define NF_REPEAT 4
23 #define NF_STOP 5
24 #define NF_MAX_VERDICT NF_STOP
25
26 /* we overload the higher bits for encoding auxiliary data such as the queue
27 * number. Not nice, but better than additional function arguments. */
28 #define NF_VERDICT_MASK 0x0000ffff
29 #define NF_VERDICT_BITS 16
30
31 #define NF_VERDICT_QMASK 0xffff0000
32 #define NF_VERDICT_QBITS 16
33
34 #define NF_QUEUE_NR(x) ((((x) << NF_VERDICT_BITS) & NF_VERDICT_QMASK) | NF_QUEUE)
35
36 /* only for userspace compatibility */
37 #ifndef __KERNEL__
38 /* Generic cache responses from hook functions.
39 <= 0x2000 is used for protocol-flags. */
40 #define NFC_UNKNOWN 0x4000
41 #define NFC_ALTERED 0x8000
42 #endif
43
44 enum nf_inet_hooks {
45 NF_INET_PRE_ROUTING,
46 NF_INET_LOCAL_IN,
47 NF_INET_FORWARD,
48 NF_INET_LOCAL_OUT,
49 NF_INET_POST_ROUTING,
50 NF_INET_NUMHOOKS
51 };
52
53 enum {
54 NFPROTO_UNSPEC = 0,
55 NFPROTO_IPV4 = 2,
56 NFPROTO_ARP = 3,
57 NFPROTO_BRIDGE = 7,
58 NFPROTO_IPV6 = 10,
59 NFPROTO_DECNET = 12,
60 NFPROTO_NUMPROTO,
61 };
62
63 union nf_inet_addr {
64 __u32 all[4];
65 __be32 ip;
66 __be32 ip6[4];
67 struct in_addr in;
68 struct in6_addr in6;
69 };
70
71 #ifdef __KERNEL__
72 #ifdef CONFIG_NETFILTER
73
74 static inline int nf_inet_addr_cmp(const union nf_inet_addr *a1,
75 const union nf_inet_addr *a2)
76 {
77 return a1->all[0] == a2->all[0] &&
78 a1->all[1] == a2->all[1] &&
79 a1->all[2] == a2->all[2] &&
80 a1->all[3] == a2->all[3];
81 }
82
83 extern void netfilter_init(void);
84
85 /* Largest hook number + 1 */
86 #define NF_MAX_HOOKS 8
87
88 struct sk_buff;
89
90 typedef unsigned int nf_hookfn(unsigned int hooknum,
91 struct sk_buff *skb,
92 const struct net_device *in,
93 const struct net_device *out,
94 int (*okfn)(struct sk_buff *));
95
96 struct nf_hook_ops
97 {
98 struct list_head list;
99
100 /* User fills in from here down. */
101 nf_hookfn *hook;
102 struct module *owner;
103 u_int8_t pf;
104 unsigned int hooknum;
105 /* Hooks are ordered in ascending priority. */
106 int priority;
107 };
108
109 struct nf_sockopt_ops
110 {
111 struct list_head list;
112
113 u_int8_t pf;
114
115 /* Non-inclusive ranges: use 0/0/NULL to never get called. */
116 int set_optmin;
117 int set_optmax;
118 int (*set)(struct sock *sk, int optval, void __user *user, unsigned int len);
119 int (*compat_set)(struct sock *sk, int optval,
120 void __user *user, unsigned int len);
121
122 int get_optmin;
123 int get_optmax;
124 int (*get)(struct sock *sk, int optval, void __user *user, int *len);
125 int (*compat_get)(struct sock *sk, int optval,
126 void __user *user, int *len);
127
128 /* Use the module struct to lock set/get code in place */
129 struct module *owner;
130 };
131
132 /* Function to register/unregister hook points. */
133 int nf_register_hook(struct nf_hook_ops *reg);
134 void nf_unregister_hook(struct nf_hook_ops *reg);
135 int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n);
136 void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n);
137
138 /* Functions to register get/setsockopt ranges (non-inclusive). You
139 need to check permissions yourself! */
140 int nf_register_sockopt(struct nf_sockopt_ops *reg);
141 void nf_unregister_sockopt(struct nf_sockopt_ops *reg);
142
143 #ifdef CONFIG_SYSCTL
144 /* Sysctl registration */
145 extern struct ctl_path nf_net_netfilter_sysctl_path[];
146 extern struct ctl_path nf_net_ipv4_netfilter_sysctl_path[];
147 #endif /* CONFIG_SYSCTL */
148
149 extern struct list_head nf_hooks[NFPROTO_NUMPROTO][NF_MAX_HOOKS];
150
151 int nf_hook_slow(u_int8_t pf, unsigned int hook, struct sk_buff *skb,
152 struct net_device *indev, struct net_device *outdev,
153 int (*okfn)(struct sk_buff *), int thresh);
154
155 /**
156 * nf_hook_thresh - call a netfilter hook
157 *
158 * Returns 1 if the hook has allowed the packet to pass. The function
159 * okfn must be invoked by the caller in this case. Any other return
160 * value indicates the packet has been consumed by the hook.
161 */
162 static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook,
163 struct sk_buff *skb,
164 struct net_device *indev,
165 struct net_device *outdev,
166 int (*okfn)(struct sk_buff *), int thresh,
167 int cond)
168 {
169 if (!cond)
170 return 1;
171 #ifndef CONFIG_NETFILTER_DEBUG
172 if (list_empty(&nf_hooks[pf][hook]))
173 return 1;
174 #endif
175 return nf_hook_slow(pf, hook, skb, indev, outdev, okfn, thresh);
176 }
177
178 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct sk_buff *skb,
179 struct net_device *indev, struct net_device *outdev,
180 int (*okfn)(struct sk_buff *))
181 {
182 return nf_hook_thresh(pf, hook, skb, indev, outdev, okfn, INT_MIN, 1);
183 }
184
185 /* Activate hook; either okfn or kfree_skb called, unless a hook
186 returns NF_STOLEN (in which case, it's up to the hook to deal with
187 the consequences).
188
189 Returns -ERRNO if packet dropped. Zero means queued, stolen or
190 accepted.
191 */
192
193 /* RR:
194 > I don't want nf_hook to return anything because people might forget
195 > about async and trust the return value to mean "packet was ok".
196
197 AK:
198 Just document it clearly, then you can expect some sense from kernel
199 coders :)
200 */
201
202 /* This is gross, but inline doesn't cut it for avoiding the function
203 call in fast path: gcc doesn't inline (needs value tracking?). --RR */
204
205 /* HX: It's slightly less gross now. */
206
207 #define NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, thresh) \
208 ({int __ret; \
209 if ((__ret=nf_hook_thresh(pf, hook, (skb), indev, outdev, okfn, thresh, 1)) == 1)\
210 __ret = (okfn)(skb); \
211 __ret;})
212
213 #define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) \
214 ({int __ret; \
215 if ((__ret=nf_hook_thresh(pf, hook, (skb), indev, outdev, okfn, INT_MIN, cond)) == 1)\
216 __ret = (okfn)(skb); \
217 __ret;})
218
219 #define NF_HOOK(pf, hook, skb, indev, outdev, okfn) \
220 NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, INT_MIN)
221
222 /* Call setsockopt() */
223 int nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt,
224 int len);
225 int nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt,
226 int *len);
227
228 int compat_nf_setsockopt(struct sock *sk, u_int8_t pf, int optval,
229 char __user *opt, int len);
230 int compat_nf_getsockopt(struct sock *sk, u_int8_t pf, int optval,
231 char __user *opt, int *len);
232
233 /* Call this before modifying an existing packet: ensures it is
234 modifiable and linear to the point you care about (writable_len).
235 Returns true or false. */
236 extern int skb_make_writable(struct sk_buff *skb, unsigned int writable_len);
237
238 struct flowi;
239 struct nf_queue_entry;
240
241 struct nf_afinfo {
242 unsigned short family;
243 __sum16 (*checksum)(struct sk_buff *skb, unsigned int hook,
244 unsigned int dataoff, u_int8_t protocol);
245 __sum16 (*checksum_partial)(struct sk_buff *skb,
246 unsigned int hook,
247 unsigned int dataoff,
248 unsigned int len,
249 u_int8_t protocol);
250 int (*route)(struct dst_entry **dst, struct flowi *fl);
251 void (*saveroute)(const struct sk_buff *skb,
252 struct nf_queue_entry *entry);
253 int (*reroute)(struct sk_buff *skb,
254 const struct nf_queue_entry *entry);
255 int route_key_size;
256 };
257
258 extern const struct nf_afinfo *nf_afinfo[NFPROTO_NUMPROTO];
259 static inline const struct nf_afinfo *nf_get_afinfo(unsigned short family)
260 {
261 return rcu_dereference(nf_afinfo[family]);
262 }
263
264 static inline __sum16
265 nf_checksum(struct sk_buff *skb, unsigned int hook, unsigned int dataoff,
266 u_int8_t protocol, unsigned short family)
267 {
268 const struct nf_afinfo *afinfo;
269 __sum16 csum = 0;
270
271 rcu_read_lock();
272 afinfo = nf_get_afinfo(family);
273 if (afinfo)
274 csum = afinfo->checksum(skb, hook, dataoff, protocol);
275 rcu_read_unlock();
276 return csum;
277 }
278
279 static inline __sum16
280 nf_checksum_partial(struct sk_buff *skb, unsigned int hook,
281 unsigned int dataoff, unsigned int len,
282 u_int8_t protocol, unsigned short family)
283 {
284 const struct nf_afinfo *afinfo;
285 __sum16 csum = 0;
286
287 rcu_read_lock();
288 afinfo = nf_get_afinfo(family);
289 if (afinfo)
290 csum = afinfo->checksum_partial(skb, hook, dataoff, len,
291 protocol);
292 rcu_read_unlock();
293 return csum;
294 }
295
296 extern int nf_register_afinfo(const struct nf_afinfo *afinfo);
297 extern void nf_unregister_afinfo(const struct nf_afinfo *afinfo);
298
299 #include <net/flow.h>
300 extern void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *);
301
302 static inline void
303 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family)
304 {
305 #ifdef CONFIG_NF_NAT_NEEDED
306 void (*decodefn)(struct sk_buff *, struct flowi *);
307
308 if (family == AF_INET) {
309 rcu_read_lock();
310 decodefn = rcu_dereference(ip_nat_decode_session);
311 if (decodefn)
312 decodefn(skb, fl);
313 rcu_read_unlock();
314 }
315 #endif
316 }
317
318 #ifdef CONFIG_PROC_FS
319 #include <linux/proc_fs.h>
320 extern struct proc_dir_entry *proc_net_netfilter;
321 #endif
322
323 #else /* !CONFIG_NETFILTER */
324 #define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb)
325 #define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) (okfn)(skb)
326 static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook,
327 struct sk_buff *skb,
328 struct net_device *indev,
329 struct net_device *outdev,
330 int (*okfn)(struct sk_buff *), int thresh,
331 int cond)
332 {
333 return okfn(skb);
334 }
335 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct sk_buff *skb,
336 struct net_device *indev, struct net_device *outdev,
337 int (*okfn)(struct sk_buff *))
338 {
339 return 1;
340 }
341 struct flowi;
342 static inline void
343 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family)
344 {
345 }
346 #endif /*CONFIG_NETFILTER*/
347
348 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
349 extern void (*ip_ct_attach)(struct sk_buff *, struct sk_buff *);
350 extern void nf_ct_attach(struct sk_buff *, struct sk_buff *);
351 extern void (*nf_ct_destroy)(struct nf_conntrack *);
352 #else
353 static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {}
354 #endif
355
356 #endif /*__KERNEL__*/
357 #endif /*__LINUX_NETFILTER_H*/
358
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