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/types.h>
7#include <linux/skbuff.h>
8#include <linux/net.h>
9#include <linux/if.h>
10#include <linux/wait.h>
11#include <linux/list.h>
12#endif
13#include <linux/compiler.h>
14
15/* Responses from hook functions. */
16#define NF_DROP 0
17#define NF_ACCEPT 1
18#define NF_STOLEN 2
19#define NF_QUEUE 3
20#define NF_REPEAT 4
21#define NF_STOP 5
22#define NF_MAX_VERDICT NF_STOP
23
24/* we overload the higher bits for encoding auxiliary data such as the queue
25 * number. Not nice, but better than additional function arguments. */
26#define NF_VERDICT_MASK 0x0000ffff
27#define NF_VERDICT_BITS 16
28
29#define NF_VERDICT_QMASK 0xffff0000
30#define NF_VERDICT_QBITS 16
31
32#define NF_QUEUE_NR(x) (((x << NF_VERDICT_QBITS) & NF_VERDICT_QMASK) | NF_QUEUE)
33
34/* only for userspace compatibility */
35#ifndef __KERNEL__
36/* Generic cache responses from hook functions.
37 <= 0x2000 is used for protocol-flags. */
38#define NFC_UNKNOWN 0x4000
39#define NFC_ALTERED 0x8000
40#endif
41
42#ifdef __KERNEL__
43#ifdef CONFIG_NETFILTER
44
45extern void netfilter_init(void);
46
47/* Largest hook number + 1 */
48#define NF_MAX_HOOKS 8
49
50struct sk_buff;
51struct net_device;
52
53typedef unsigned int nf_hookfn(unsigned int hooknum,
54 struct sk_buff **skb,
55 const struct net_device *in,
56 const struct net_device *out,
57 int (*okfn)(struct sk_buff *));
58
59struct nf_hook_ops
60{
61 struct list_head list;
62
63 /* User fills in from here down. */
64 nf_hookfn *hook;
65 struct module *owner;
66 int pf;
67 int hooknum;
68 /* Hooks are ordered in ascending priority. */
69 int priority;
70};
71
72struct nf_sockopt_ops
73{
74 struct list_head list;
75
76 int pf;
77
78 /* Non-inclusive ranges: use 0/0/NULL to never get called. */
79 int set_optmin;
80 int set_optmax;
81 int (*set)(struct sock *sk, int optval, void __user *user, unsigned int len);
82 int (*compat_set)(struct sock *sk, int optval,
83 void __user *user, unsigned int len);
84
85 int get_optmin;
86 int get_optmax;
87 int (*get)(struct sock *sk, int optval, void __user *user, int *len);
88 int (*compat_get)(struct sock *sk, int optval,
89 void __user *user, int *len);
90
91 /* Number of users inside set() or get(). */
92 unsigned int use;
93 struct task_struct *cleanup_task;
94};
95
96/* Each queued (to userspace) skbuff has one of these. */
97struct nf_info
98{
99 /* The ops struct which sent us to userspace. */
100 struct nf_hook_ops *elem;
101
102 /* If we're sent to userspace, this keeps housekeeping info */
103 int pf;
104 unsigned int hook;
105 struct net_device *indev, *outdev;
106 int (*okfn)(struct sk_buff *);
107};
108
109/* Function to register/unregister hook points. */
110int nf_register_hook(struct nf_hook_ops *reg);
111void nf_unregister_hook(struct nf_hook_ops *reg);
112int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n);
113void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n);
114
115/* Functions to register get/setsockopt ranges (non-inclusive). You
116 need to check permissions yourself! */
117int nf_register_sockopt(struct nf_sockopt_ops *reg);
118void nf_unregister_sockopt(struct nf_sockopt_ops *reg);
119
120#ifdef CONFIG_SYSCTL
121/* Sysctl registration */
122struct ctl_table_header *nf_register_sysctl_table(struct ctl_table *path,
123 struct ctl_table *table);
124void nf_unregister_sysctl_table(struct ctl_table_header *header,
125 struct ctl_table *table);
126extern struct ctl_table nf_net_netfilter_sysctl_path[];
127extern struct ctl_table nf_net_ipv4_netfilter_sysctl_path[];
128#endif /* CONFIG_SYSCTL */
129
130extern struct list_head nf_hooks[NPROTO][NF_MAX_HOOKS];
131
132/* those NF_LOG_* defines and struct nf_loginfo are legacy definitios that will
133 * disappear once iptables is replaced with pkttables. Please DO NOT use them
134 * for any new code! */
135#define NF_LOG_TCPSEQ 0x01 /* Log TCP sequence numbers */
136#define NF_LOG_TCPOPT 0x02 /* Log TCP options */
137#define NF_LOG_IPOPT 0x04 /* Log IP options */
138#define NF_LOG_UID 0x08 /* Log UID owning local socket */
139#define NF_LOG_MASK 0x0f
140
141#define NF_LOG_TYPE_LOG 0x01
142#define NF_LOG_TYPE_ULOG 0x02
143
144struct nf_loginfo {
145 u_int8_t type;
146 union {
147 struct {
148 u_int32_t copy_len;
149 u_int16_t group;
150 u_int16_t qthreshold;
151 } ulog;
152 struct {
153 u_int8_t level;
154 u_int8_t logflags;
155 } log;
156 } u;
157};
158
159typedef void nf_logfn(unsigned int pf,
160 unsigned int hooknum,
161 const struct sk_buff *skb,
162 const struct net_device *in,
163 const struct net_device *out,
164 const struct nf_loginfo *li,
165 const char *prefix);
166
167struct nf_logger {
168 struct module *me;
169 nf_logfn *logfn;
170 char *name;
171};
172
173/* Function to register/unregister log function. */
174int nf_log_register(int pf, struct nf_logger *logger);
175int nf_log_unregister_pf(int pf);
176void nf_log_unregister_logger(struct nf_logger *logger);
177
178/* Calls the registered backend logging function */
179void nf_log_packet(int pf,
180 unsigned int hooknum,
181 const struct sk_buff *skb,
182 const struct net_device *in,
183 const struct net_device *out,
184 struct nf_loginfo *li,
185 const char *fmt, ...);
186
187int nf_hook_slow(int pf, unsigned int hook, struct sk_buff **pskb,
188 struct net_device *indev, struct net_device *outdev,
189 int (*okfn)(struct sk_buff *), int thresh);
190
191/**
192 * nf_hook_thresh - call a netfilter hook
193 *
194 * Returns 1 if the hook has allowed the packet to pass. The function
195 * okfn must be invoked by the caller in this case. Any other return
196 * value indicates the packet has been consumed by the hook.
197 */
198static inline int nf_hook_thresh(int pf, unsigned int hook,
199 struct sk_buff **pskb,
200 struct net_device *indev,
201 struct net_device *outdev,
202 int (*okfn)(struct sk_buff *), int thresh,
203 int cond)
204{
205 if (!cond)
206 return 1;
207#ifndef CONFIG_NETFILTER_DEBUG
208 if (list_empty(&nf_hooks[pf][hook]))
209 return 1;
210#endif
211 return nf_hook_slow(pf, hook, pskb, indev, outdev, okfn, thresh);
212}
213
214static inline int nf_hook(int pf, unsigned int hook, struct sk_buff **pskb,
215 struct net_device *indev, struct net_device *outdev,
216 int (*okfn)(struct sk_buff *))
217{
218 return nf_hook_thresh(pf, hook, pskb, indev, outdev, okfn, INT_MIN, 1);
219}
220
221/* Activate hook; either okfn or kfree_skb called, unless a hook
222 returns NF_STOLEN (in which case, it's up to the hook to deal with
223 the consequences).
224
225 Returns -ERRNO if packet dropped. Zero means queued, stolen or
226 accepted.
227*/
228
229/* RR:
230 > I don't want nf_hook to return anything because people might forget
231 > about async and trust the return value to mean "packet was ok".
232
233 AK:
234 Just document it clearly, then you can expect some sense from kernel
235 coders :)
236*/
237
238/* This is gross, but inline doesn't cut it for avoiding the function
239 call in fast path: gcc doesn't inline (needs value tracking?). --RR */
240
241/* HX: It's slightly less gross now. */
242
243#define NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, thresh) \
244({int __ret; \
245if ((__ret=nf_hook_thresh(pf, hook, &(skb), indev, outdev, okfn, thresh, 1)) == 1)\
246 __ret = (okfn)(skb); \
247__ret;})
248
249#define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) \
250({int __ret; \
251if ((__ret=nf_hook_thresh(pf, hook, &(skb), indev, outdev, okfn, INT_MIN, cond)) == 1)\
252 __ret = (okfn)(skb); \
253__ret;})
254
255#define NF_HOOK(pf, hook, skb, indev, outdev, okfn) \
256 NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, INT_MIN)
257
258/* Call setsockopt() */
259int nf_setsockopt(struct sock *sk, int pf, int optval, char __user *opt,
260 int len);
261int nf_getsockopt(struct sock *sk, int pf, int optval, char __user *opt,
262 int *len);
263
264int compat_nf_setsockopt(struct sock *sk, int pf, int optval,
265 char __user *opt, int len);
266int compat_nf_getsockopt(struct sock *sk, int pf, int optval,
267 char __user *opt, int *len);
268
269/* Packet queuing */
270struct nf_queue_handler {
271 int (*outfn)(struct sk_buff *skb, struct nf_info *info,
272 unsigned int queuenum, void *data);
273 void *data;
274 char *name;
275};
276extern int nf_register_queue_handler(int pf,
277 struct nf_queue_handler *qh);
278extern int nf_unregister_queue_handler(int pf);
279extern void nf_unregister_queue_handlers(struct nf_queue_handler *qh);
280extern void nf_reinject(struct sk_buff *skb,
281 struct nf_info *info,
282 unsigned int verdict);
283
284extern void (*ip_ct_attach)(struct sk_buff *, struct sk_buff *);
285extern void nf_ct_attach(struct sk_buff *, struct sk_buff *);
286
287/* FIXME: Before cache is ever used, this must be implemented for real. */
288extern void nf_invalidate_cache(int pf);
289
290/* Call this before modifying an existing packet: ensures it is
291 modifiable and linear to the point you care about (writable_len).
292 Returns true or false. */
293extern int skb_make_writable(struct sk_buff **pskb, unsigned int writable_len);
294
295static inline void nf_csum_replace4(__sum16 *sum, __be32 from, __be32 to)
296{
297 __be32 diff[] = { ~from, to };
298
299 *sum = csum_fold(csum_partial((char *)diff, sizeof(diff), ~csum_unfold(*sum)));
300}
301
302static inline void nf_csum_replace2(__sum16 *sum, __be16 from, __be16 to)
303{
304 nf_csum_replace4(sum, (__force __be32)from, (__force __be32)to);
305}
306
307extern void nf_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb,
308 __be32 from, __be32 to, int pseudohdr);
309
310static inline void nf_proto_csum_replace2(__sum16 *sum, struct sk_buff *skb,
311 __be16 from, __be16 to, int pseudohdr)
312{
313 nf_proto_csum_replace4(sum, skb, (__force __be32)from,
314 (__force __be32)to, pseudohdr);
315}
316
317struct nf_afinfo {
318 unsigned short family;
319 __sum16 (*checksum)(struct sk_buff *skb, unsigned int hook,
320 unsigned int dataoff, u_int8_t protocol);
321 void (*saveroute)(const struct sk_buff *skb,
322 struct nf_info *info);
323 int (*reroute)(struct sk_buff **skb,
324 const struct nf_info *info);
325 int route_key_size;
326};
327
328extern struct nf_afinfo *nf_afinfo[];
329static inline struct nf_afinfo *nf_get_afinfo(unsigned short family)
330{
331 return rcu_dereference(nf_afinfo[family]);
332}
333
334static inline __sum16
335nf_checksum(struct sk_buff *skb, unsigned int hook, unsigned int dataoff,
336 u_int8_t protocol, unsigned short family)
337{
338 struct nf_afinfo *afinfo;
339 __sum16 csum = 0;
340
341 rcu_read_lock();
342 afinfo = nf_get_afinfo(family);
343 if (afinfo)
344 csum = afinfo->checksum(skb, hook, dataoff, protocol);
345 rcu_read_unlock();
346 return csum;
347}
348
349extern int nf_register_afinfo(struct nf_afinfo *afinfo);
350extern void nf_unregister_afinfo(struct nf_afinfo *afinfo);
351
352#define nf_info_reroute(x) ((void *)x + sizeof(struct nf_info))
353
354#include <net/flow.h>
355extern void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *);
356
357static inline void
358nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, int family)
359{
360#if defined(CONFIG_IP_NF_NAT_NEEDED) || defined(CONFIG_NF_NAT_NEEDED)
361 void (*decodefn)(struct sk_buff *, struct flowi *);
362
363 if (family == AF_INET && (decodefn = ip_nat_decode_session) != NULL)
364 decodefn(skb, fl);
365#endif
366}
367
368#ifdef CONFIG_PROC_FS
369#include <linux/proc_fs.h>
370extern struct proc_dir_entry *proc_net_netfilter;
371#endif
372
373#else /* !CONFIG_NETFILTER */
374#define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb)
375#define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) (okfn)(skb)
376static inline int nf_hook_thresh(int pf, unsigned int hook,
377 struct sk_buff **pskb,
378 struct net_device *indev,
379 struct net_device *outdev,
380 int (*okfn)(struct sk_buff *), int thresh,
381 int cond)
382{
383 return okfn(*pskb);
384}
385static inline int nf_hook(int pf, unsigned int hook, struct sk_buff **pskb,
386 struct net_device *indev, struct net_device *outdev,
387 int (*okfn)(struct sk_buff *))
388{
389 return 1;
390}
391static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {}
392struct flowi;
393static inline void
394nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, int family) {}
395#endif /*CONFIG_NETFILTER*/
396
397#endif /*__KERNEL__*/
398#endif /*__LINUX_NETFILTER_H*/