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{
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
109struct 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. */
133int nf_register_hook(struct nf_hook_ops *reg);
134void nf_unregister_hook(struct nf_hook_ops *reg);
135int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n);
136void 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! */
140int nf_register_sockopt(struct nf_sockopt_ops *reg);
141void nf_unregister_sockopt(struct nf_sockopt_ops *reg);
142
143#ifdef CONFIG_SYSCTL
144/* Sysctl registration */
145extern struct ctl_path nf_net_netfilter_sysctl_path[];
146extern struct ctl_path nf_net_ipv4_netfilter_sysctl_path[];
147#endif /* CONFIG_SYSCTL */
148
149extern struct list_head nf_hooks[NFPROTO_NUMPROTO][NF_MAX_HOOKS];
150
151int 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 */
162static 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
178static 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; \
209if ((__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; \
215if ((__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() */
223int nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt,
224 int len);
225int nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt,
226 int *len);
227
228int compat_nf_setsockopt(struct sock *sk, u_int8_t pf, int optval,
229 char __user *opt, int len);
230int 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. */
236extern int skb_make_writable(struct sk_buff *skb, unsigned int writable_len);
237
238struct flowi;
239struct nf_queue_entry;
240
241struct 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
258extern const struct nf_afinfo *nf_afinfo[NFPROTO_NUMPROTO];
259static inline const struct nf_afinfo *nf_get_afinfo(unsigned short family)
260{
261 return rcu_dereference(nf_afinfo[family]);
262}
263
264static inline __sum16
265nf_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
279static inline __sum16
280nf_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
296extern int nf_register_afinfo(const struct nf_afinfo *afinfo);
297extern void nf_unregister_afinfo(const struct nf_afinfo *afinfo);
298
299#include <net/flow.h>
300extern void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *);
301
302static inline void
303nf_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>
320extern 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)
326static 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}
335static 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}
341struct flowi;
342static inline void
343nf_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)
349extern void (*ip_ct_attach)(struct sk_buff *, struct sk_buff *);
350extern void nf_ct_attach(struct sk_buff *, struct sk_buff *);
351extern void (*nf_ct_destroy)(struct nf_conntrack *);
352#else
353static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {}
354#endif
355
356#endif /*__KERNEL__*/
357#endif /*__LINUX_NETFILTER_H*/