Linux kernel mirror (for testing)
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linux
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
44enum 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
53enum {
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
63union 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
74static 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
83extern void netfilter_init(void);
84
85/* Largest hook number + 1 */
86#define NF_MAX_HOOKS 8
87
88struct sk_buff;
89
90typedef 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
96struct nf_hook_ops {
97 struct list_head list;
98
99 /* User fills in from here down. */
100 nf_hookfn *hook;
101 struct module *owner;
102 u_int8_t pf;
103 unsigned int hooknum;
104 /* Hooks are ordered in ascending priority. */
105 int priority;
106};
107
108struct nf_sockopt_ops {
109 struct list_head list;
110
111 u_int8_t pf;
112
113 /* Non-inclusive ranges: use 0/0/NULL to never get called. */
114 int set_optmin;
115 int set_optmax;
116 int (*set)(struct sock *sk, int optval, void __user *user, unsigned int len);
117 int (*compat_set)(struct sock *sk, int optval,
118 void __user *user, unsigned int len);
119
120 int get_optmin;
121 int get_optmax;
122 int (*get)(struct sock *sk, int optval, void __user *user, int *len);
123 int (*compat_get)(struct sock *sk, int optval,
124 void __user *user, int *len);
125
126 /* Use the module struct to lock set/get code in place */
127 struct module *owner;
128};
129
130/* Function to register/unregister hook points. */
131int nf_register_hook(struct nf_hook_ops *reg);
132void nf_unregister_hook(struct nf_hook_ops *reg);
133int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n);
134void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n);
135
136/* Functions to register get/setsockopt ranges (non-inclusive). You
137 need to check permissions yourself! */
138int nf_register_sockopt(struct nf_sockopt_ops *reg);
139void nf_unregister_sockopt(struct nf_sockopt_ops *reg);
140
141#ifdef CONFIG_SYSCTL
142/* Sysctl registration */
143extern struct ctl_path nf_net_netfilter_sysctl_path[];
144extern struct ctl_path nf_net_ipv4_netfilter_sysctl_path[];
145#endif /* CONFIG_SYSCTL */
146
147extern struct list_head nf_hooks[NFPROTO_NUMPROTO][NF_MAX_HOOKS];
148
149int nf_hook_slow(u_int8_t pf, unsigned int hook, struct sk_buff *skb,
150 struct net_device *indev, struct net_device *outdev,
151 int (*okfn)(struct sk_buff *), int thresh);
152
153/**
154 * nf_hook_thresh - call a netfilter hook
155 *
156 * Returns 1 if the hook has allowed the packet to pass. The function
157 * okfn must be invoked by the caller in this case. Any other return
158 * value indicates the packet has been consumed by the hook.
159 */
160static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook,
161 struct sk_buff *skb,
162 struct net_device *indev,
163 struct net_device *outdev,
164 int (*okfn)(struct sk_buff *), int thresh,
165 int cond)
166{
167 if (!cond)
168 return 1;
169#ifndef CONFIG_NETFILTER_DEBUG
170 if (list_empty(&nf_hooks[pf][hook]))
171 return 1;
172#endif
173 return nf_hook_slow(pf, hook, skb, indev, outdev, okfn, thresh);
174}
175
176static inline int nf_hook(u_int8_t pf, unsigned int hook, struct sk_buff *skb,
177 struct net_device *indev, struct net_device *outdev,
178 int (*okfn)(struct sk_buff *))
179{
180 return nf_hook_thresh(pf, hook, skb, indev, outdev, okfn, INT_MIN, 1);
181}
182
183/* Activate hook; either okfn or kfree_skb called, unless a hook
184 returns NF_STOLEN (in which case, it's up to the hook to deal with
185 the consequences).
186
187 Returns -ERRNO if packet dropped. Zero means queued, stolen or
188 accepted.
189*/
190
191/* RR:
192 > I don't want nf_hook to return anything because people might forget
193 > about async and trust the return value to mean "packet was ok".
194
195 AK:
196 Just document it clearly, then you can expect some sense from kernel
197 coders :)
198*/
199
200/* This is gross, but inline doesn't cut it for avoiding the function
201 call in fast path: gcc doesn't inline (needs value tracking?). --RR */
202
203/* HX: It's slightly less gross now. */
204
205#define NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, thresh) \
206({int __ret; \
207if ((__ret=nf_hook_thresh(pf, hook, (skb), indev, outdev, okfn, thresh, 1)) == 1)\
208 __ret = (okfn)(skb); \
209__ret;})
210
211#define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) \
212({int __ret; \
213if ((__ret=nf_hook_thresh(pf, hook, (skb), indev, outdev, okfn, INT_MIN, cond)) == 1)\
214 __ret = (okfn)(skb); \
215__ret;})
216
217#define NF_HOOK(pf, hook, skb, indev, outdev, okfn) \
218 NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, INT_MIN)
219
220/* Call setsockopt() */
221int nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt,
222 unsigned int len);
223int nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt,
224 int *len);
225
226int compat_nf_setsockopt(struct sock *sk, u_int8_t pf, int optval,
227 char __user *opt, unsigned int len);
228int compat_nf_getsockopt(struct sock *sk, u_int8_t pf, int optval,
229 char __user *opt, int *len);
230
231/* Call this before modifying an existing packet: ensures it is
232 modifiable and linear to the point you care about (writable_len).
233 Returns true or false. */
234extern int skb_make_writable(struct sk_buff *skb, unsigned int writable_len);
235
236struct flowi;
237struct nf_queue_entry;
238
239struct nf_afinfo {
240 unsigned short family;
241 __sum16 (*checksum)(struct sk_buff *skb, unsigned int hook,
242 unsigned int dataoff, u_int8_t protocol);
243 __sum16 (*checksum_partial)(struct sk_buff *skb,
244 unsigned int hook,
245 unsigned int dataoff,
246 unsigned int len,
247 u_int8_t protocol);
248 int (*route)(struct dst_entry **dst, struct flowi *fl);
249 void (*saveroute)(const struct sk_buff *skb,
250 struct nf_queue_entry *entry);
251 int (*reroute)(struct sk_buff *skb,
252 const struct nf_queue_entry *entry);
253 int route_key_size;
254};
255
256extern const struct nf_afinfo *nf_afinfo[NFPROTO_NUMPROTO];
257static inline const struct nf_afinfo *nf_get_afinfo(unsigned short family)
258{
259 return rcu_dereference(nf_afinfo[family]);
260}
261
262static inline __sum16
263nf_checksum(struct sk_buff *skb, unsigned int hook, unsigned int dataoff,
264 u_int8_t protocol, unsigned short family)
265{
266 const struct nf_afinfo *afinfo;
267 __sum16 csum = 0;
268
269 rcu_read_lock();
270 afinfo = nf_get_afinfo(family);
271 if (afinfo)
272 csum = afinfo->checksum(skb, hook, dataoff, protocol);
273 rcu_read_unlock();
274 return csum;
275}
276
277static inline __sum16
278nf_checksum_partial(struct sk_buff *skb, unsigned int hook,
279 unsigned int dataoff, unsigned int len,
280 u_int8_t protocol, unsigned short family)
281{
282 const struct nf_afinfo *afinfo;
283 __sum16 csum = 0;
284
285 rcu_read_lock();
286 afinfo = nf_get_afinfo(family);
287 if (afinfo)
288 csum = afinfo->checksum_partial(skb, hook, dataoff, len,
289 protocol);
290 rcu_read_unlock();
291 return csum;
292}
293
294extern int nf_register_afinfo(const struct nf_afinfo *afinfo);
295extern void nf_unregister_afinfo(const struct nf_afinfo *afinfo);
296
297#include <net/flow.h>
298extern void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *);
299
300static inline void
301nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family)
302{
303#ifdef CONFIG_NF_NAT_NEEDED
304 void (*decodefn)(struct sk_buff *, struct flowi *);
305
306 if (family == AF_INET) {
307 rcu_read_lock();
308 decodefn = rcu_dereference(ip_nat_decode_session);
309 if (decodefn)
310 decodefn(skb, fl);
311 rcu_read_unlock();
312 }
313#endif
314}
315
316#ifdef CONFIG_PROC_FS
317#include <linux/proc_fs.h>
318extern struct proc_dir_entry *proc_net_netfilter;
319#endif
320
321#else /* !CONFIG_NETFILTER */
322#define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb)
323#define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) (okfn)(skb)
324static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook,
325 struct sk_buff *skb,
326 struct net_device *indev,
327 struct net_device *outdev,
328 int (*okfn)(struct sk_buff *), int thresh,
329 int cond)
330{
331 return okfn(skb);
332}
333static inline int nf_hook(u_int8_t pf, unsigned int hook, struct sk_buff *skb,
334 struct net_device *indev, struct net_device *outdev,
335 int (*okfn)(struct sk_buff *))
336{
337 return 1;
338}
339struct flowi;
340static inline void
341nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family)
342{
343}
344#endif /*CONFIG_NETFILTER*/
345
346#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
347extern void (*ip_ct_attach)(struct sk_buff *, struct sk_buff *);
348extern void nf_ct_attach(struct sk_buff *, struct sk_buff *);
349extern void (*nf_ct_destroy)(struct nf_conntrack *);
350#else
351static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {}
352#endif
353
354#endif /*__KERNEL__*/
355#endif /*__LINUX_NETFILTER_H*/