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