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 or errno values. Not nice, but better than additional function
28 * arguments. */
29#define NF_VERDICT_MASK 0x000000ff
30
31/* extra verdict flags have mask 0x0000ff00 */
32#define NF_VERDICT_FLAG_QUEUE_BYPASS 0x00008000
33
34/* queue number (NF_QUEUE) or errno (NF_DROP) */
35#define NF_VERDICT_QMASK 0xffff0000
36#define NF_VERDICT_QBITS 16
37
38#define NF_QUEUE_NR(x) ((((x) << 16) & NF_VERDICT_QMASK) | NF_QUEUE)
39
40#define NF_DROP_ERR(x) (((-x) << 16) | NF_DROP)
41
42/* only for userspace compatibility */
43#ifndef __KERNEL__
44/* Generic cache responses from hook functions.
45 <= 0x2000 is used for protocol-flags. */
46#define NFC_UNKNOWN 0x4000
47#define NFC_ALTERED 0x8000
48
49/* NF_VERDICT_BITS should be 8 now, but userspace might break if this changes */
50#define NF_VERDICT_BITS 16
51#endif
52
53enum nf_inet_hooks {
54 NF_INET_PRE_ROUTING,
55 NF_INET_LOCAL_IN,
56 NF_INET_FORWARD,
57 NF_INET_LOCAL_OUT,
58 NF_INET_POST_ROUTING,
59 NF_INET_NUMHOOKS
60};
61
62enum {
63 NFPROTO_UNSPEC = 0,
64 NFPROTO_IPV4 = 2,
65 NFPROTO_ARP = 3,
66 NFPROTO_BRIDGE = 7,
67 NFPROTO_IPV6 = 10,
68 NFPROTO_DECNET = 12,
69 NFPROTO_NUMPROTO,
70};
71
72union nf_inet_addr {
73 __u32 all[4];
74 __be32 ip;
75 __be32 ip6[4];
76 struct in_addr in;
77 struct in6_addr in6;
78};
79
80#ifdef __KERNEL__
81#ifdef CONFIG_NETFILTER
82static inline int NF_DROP_GETERR(int verdict)
83{
84 return -(verdict >> NF_VERDICT_QBITS);
85}
86
87static inline int nf_inet_addr_cmp(const union nf_inet_addr *a1,
88 const union nf_inet_addr *a2)
89{
90 return a1->all[0] == a2->all[0] &&
91 a1->all[1] == a2->all[1] &&
92 a1->all[2] == a2->all[2] &&
93 a1->all[3] == a2->all[3];
94}
95
96extern void netfilter_init(void);
97
98/* Largest hook number + 1 */
99#define NF_MAX_HOOKS 8
100
101struct sk_buff;
102
103typedef unsigned int nf_hookfn(unsigned int hooknum,
104 struct sk_buff *skb,
105 const struct net_device *in,
106 const struct net_device *out,
107 int (*okfn)(struct sk_buff *));
108
109struct nf_hook_ops {
110 struct list_head list;
111
112 /* User fills in from here down. */
113 nf_hookfn *hook;
114 struct module *owner;
115 u_int8_t pf;
116 unsigned int hooknum;
117 /* Hooks are ordered in ascending priority. */
118 int priority;
119};
120
121struct nf_sockopt_ops {
122 struct list_head list;
123
124 u_int8_t pf;
125
126 /* Non-inclusive ranges: use 0/0/NULL to never get called. */
127 int set_optmin;
128 int set_optmax;
129 int (*set)(struct sock *sk, int optval, void __user *user, unsigned int len);
130#ifdef CONFIG_COMPAT
131 int (*compat_set)(struct sock *sk, int optval,
132 void __user *user, unsigned int len);
133#endif
134 int get_optmin;
135 int get_optmax;
136 int (*get)(struct sock *sk, int optval, void __user *user, int *len);
137#ifdef CONFIG_COMPAT
138 int (*compat_get)(struct sock *sk, int optval,
139 void __user *user, int *len);
140#endif
141 /* Use the module struct to lock set/get code in place */
142 struct module *owner;
143};
144
145/* Function to register/unregister hook points. */
146int nf_register_hook(struct nf_hook_ops *reg);
147void nf_unregister_hook(struct nf_hook_ops *reg);
148int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n);
149void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n);
150
151/* Functions to register get/setsockopt ranges (non-inclusive). You
152 need to check permissions yourself! */
153int nf_register_sockopt(struct nf_sockopt_ops *reg);
154void nf_unregister_sockopt(struct nf_sockopt_ops *reg);
155
156#ifdef CONFIG_SYSCTL
157/* Sysctl registration */
158extern struct ctl_path nf_net_netfilter_sysctl_path[];
159extern struct ctl_path nf_net_ipv4_netfilter_sysctl_path[];
160#endif /* CONFIG_SYSCTL */
161
162extern struct list_head nf_hooks[NFPROTO_NUMPROTO][NF_MAX_HOOKS];
163
164int nf_hook_slow(u_int8_t pf, unsigned int hook, struct sk_buff *skb,
165 struct net_device *indev, struct net_device *outdev,
166 int (*okfn)(struct sk_buff *), int thresh);
167
168/**
169 * nf_hook_thresh - call a netfilter hook
170 *
171 * Returns 1 if the hook has allowed the packet to pass. The function
172 * okfn must be invoked by the caller in this case. Any other return
173 * value indicates the packet has been consumed by the hook.
174 */
175static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook,
176 struct sk_buff *skb,
177 struct net_device *indev,
178 struct net_device *outdev,
179 int (*okfn)(struct sk_buff *), int thresh)
180{
181#ifndef CONFIG_NETFILTER_DEBUG
182 if (list_empty(&nf_hooks[pf][hook]))
183 return 1;
184#endif
185 return nf_hook_slow(pf, hook, skb, indev, outdev, okfn, thresh);
186}
187
188static inline int nf_hook(u_int8_t pf, unsigned int hook, struct sk_buff *skb,
189 struct net_device *indev, struct net_device *outdev,
190 int (*okfn)(struct sk_buff *))
191{
192 return nf_hook_thresh(pf, hook, skb, indev, outdev, okfn, INT_MIN);
193}
194
195/* Activate hook; either okfn or kfree_skb called, unless a hook
196 returns NF_STOLEN (in which case, it's up to the hook to deal with
197 the consequences).
198
199 Returns -ERRNO if packet dropped. Zero means queued, stolen or
200 accepted.
201*/
202
203/* RR:
204 > I don't want nf_hook to return anything because people might forget
205 > about async and trust the return value to mean "packet was ok".
206
207 AK:
208 Just document it clearly, then you can expect some sense from kernel
209 coders :)
210*/
211
212static inline int
213NF_HOOK_THRESH(uint8_t pf, unsigned int hook, struct sk_buff *skb,
214 struct net_device *in, struct net_device *out,
215 int (*okfn)(struct sk_buff *), int thresh)
216{
217 int ret = nf_hook_thresh(pf, hook, skb, in, out, okfn, thresh);
218 if (ret == 1)
219 ret = okfn(skb);
220 return ret;
221}
222
223static inline int
224NF_HOOK_COND(uint8_t pf, unsigned int hook, struct sk_buff *skb,
225 struct net_device *in, struct net_device *out,
226 int (*okfn)(struct sk_buff *), bool cond)
227{
228 int ret;
229
230 if (!cond ||
231 ((ret = nf_hook_thresh(pf, hook, skb, in, out, okfn, INT_MIN)) == 1))
232 ret = okfn(skb);
233 return ret;
234}
235
236static inline int
237NF_HOOK(uint8_t pf, unsigned int hook, struct sk_buff *skb,
238 struct net_device *in, struct net_device *out,
239 int (*okfn)(struct sk_buff *))
240{
241 return NF_HOOK_THRESH(pf, hook, skb, in, out, okfn, INT_MIN);
242}
243
244/* Call setsockopt() */
245int nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt,
246 unsigned int len);
247int nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt,
248 int *len);
249#ifdef CONFIG_COMPAT
250int compat_nf_setsockopt(struct sock *sk, u_int8_t pf, int optval,
251 char __user *opt, unsigned int len);
252int compat_nf_getsockopt(struct sock *sk, u_int8_t pf, int optval,
253 char __user *opt, int *len);
254#endif
255
256/* Call this before modifying an existing packet: ensures it is
257 modifiable and linear to the point you care about (writable_len).
258 Returns true or false. */
259extern int skb_make_writable(struct sk_buff *skb, unsigned int writable_len);
260
261struct flowi;
262struct nf_queue_entry;
263
264struct nf_afinfo {
265 unsigned short family;
266 __sum16 (*checksum)(struct sk_buff *skb, unsigned int hook,
267 unsigned int dataoff, u_int8_t protocol);
268 __sum16 (*checksum_partial)(struct sk_buff *skb,
269 unsigned int hook,
270 unsigned int dataoff,
271 unsigned int len,
272 u_int8_t protocol);
273 int (*route)(struct dst_entry **dst, struct flowi *fl);
274 void (*saveroute)(const struct sk_buff *skb,
275 struct nf_queue_entry *entry);
276 int (*reroute)(struct sk_buff *skb,
277 const struct nf_queue_entry *entry);
278 int route_key_size;
279};
280
281extern const struct nf_afinfo __rcu *nf_afinfo[NFPROTO_NUMPROTO];
282static inline const struct nf_afinfo *nf_get_afinfo(unsigned short family)
283{
284 return rcu_dereference(nf_afinfo[family]);
285}
286
287static inline __sum16
288nf_checksum(struct sk_buff *skb, unsigned int hook, unsigned int dataoff,
289 u_int8_t protocol, unsigned short family)
290{
291 const struct nf_afinfo *afinfo;
292 __sum16 csum = 0;
293
294 rcu_read_lock();
295 afinfo = nf_get_afinfo(family);
296 if (afinfo)
297 csum = afinfo->checksum(skb, hook, dataoff, protocol);
298 rcu_read_unlock();
299 return csum;
300}
301
302static inline __sum16
303nf_checksum_partial(struct sk_buff *skb, unsigned int hook,
304 unsigned int dataoff, unsigned int len,
305 u_int8_t protocol, unsigned short family)
306{
307 const struct nf_afinfo *afinfo;
308 __sum16 csum = 0;
309
310 rcu_read_lock();
311 afinfo = nf_get_afinfo(family);
312 if (afinfo)
313 csum = afinfo->checksum_partial(skb, hook, dataoff, len,
314 protocol);
315 rcu_read_unlock();
316 return csum;
317}
318
319extern int nf_register_afinfo(const struct nf_afinfo *afinfo);
320extern void nf_unregister_afinfo(const struct nf_afinfo *afinfo);
321
322#include <net/flow.h>
323extern void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *);
324
325static inline void
326nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family)
327{
328#ifdef CONFIG_NF_NAT_NEEDED
329 void (*decodefn)(struct sk_buff *, struct flowi *);
330
331 if (family == AF_INET) {
332 rcu_read_lock();
333 decodefn = rcu_dereference(ip_nat_decode_session);
334 if (decodefn)
335 decodefn(skb, fl);
336 rcu_read_unlock();
337 }
338#endif
339}
340
341#ifdef CONFIG_PROC_FS
342#include <linux/proc_fs.h>
343extern struct proc_dir_entry *proc_net_netfilter;
344#endif
345
346#else /* !CONFIG_NETFILTER */
347#define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb)
348#define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) (okfn)(skb)
349static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook,
350 struct sk_buff *skb,
351 struct net_device *indev,
352 struct net_device *outdev,
353 int (*okfn)(struct sk_buff *), int thresh)
354{
355 return okfn(skb);
356}
357static inline int nf_hook(u_int8_t pf, unsigned int hook, struct sk_buff *skb,
358 struct net_device *indev, struct net_device *outdev,
359 int (*okfn)(struct sk_buff *))
360{
361 return 1;
362}
363struct flowi;
364static inline void
365nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family)
366{
367}
368#endif /*CONFIG_NETFILTER*/
369
370#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
371extern void (*ip_ct_attach)(struct sk_buff *, struct sk_buff *) __rcu;
372extern void nf_ct_attach(struct sk_buff *, struct sk_buff *);
373extern void (*nf_ct_destroy)(struct nf_conntrack *) __rcu;
374#else
375static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {}
376#endif
377
378#endif /*__KERNEL__*/
379#endif /*__LINUX_NETFILTER_H*/