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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
120extern struct list_head nf_hooks[NPROTO][NF_MAX_HOOKS];
121
122/* those NF_LOG_* defines and struct nf_loginfo are legacy definitios that will
123 * disappear once iptables is replaced with pkttables. Please DO NOT use them
124 * for any new code! */
125#define NF_LOG_TCPSEQ 0x01 /* Log TCP sequence numbers */
126#define NF_LOG_TCPOPT 0x02 /* Log TCP options */
127#define NF_LOG_IPOPT 0x04 /* Log IP options */
128#define NF_LOG_UID 0x08 /* Log UID owning local socket */
129#define NF_LOG_MASK 0x0f
130
131#define NF_LOG_TYPE_LOG 0x01
132#define NF_LOG_TYPE_ULOG 0x02
133
134struct nf_loginfo {
135 u_int8_t type;
136 union {
137 struct {
138 u_int32_t copy_len;
139 u_int16_t group;
140 u_int16_t qthreshold;
141 } ulog;
142 struct {
143 u_int8_t level;
144 u_int8_t logflags;
145 } log;
146 } u;
147};
148
149typedef void nf_logfn(unsigned int pf,
150 unsigned int hooknum,
151 const struct sk_buff *skb,
152 const struct net_device *in,
153 const struct net_device *out,
154 const struct nf_loginfo *li,
155 const char *prefix);
156
157struct nf_logger {
158 struct module *me;
159 nf_logfn *logfn;
160 char *name;
161};
162
163/* Function to register/unregister log function. */
164int nf_log_register(int pf, struct nf_logger *logger);
165int nf_log_unregister_pf(int pf);
166void nf_log_unregister_logger(struct nf_logger *logger);
167
168/* Calls the registered backend logging function */
169void nf_log_packet(int pf,
170 unsigned int hooknum,
171 const struct sk_buff *skb,
172 const struct net_device *in,
173 const struct net_device *out,
174 struct nf_loginfo *li,
175 const char *fmt, ...);
176
177int nf_hook_slow(int pf, unsigned int hook, struct sk_buff **pskb,
178 struct net_device *indev, struct net_device *outdev,
179 int (*okfn)(struct sk_buff *), int thresh);
180
181/**
182 * nf_hook_thresh - call a netfilter hook
183 *
184 * Returns 1 if the hook has allowed the packet to pass. The function
185 * okfn must be invoked by the caller in this case. Any other return
186 * value indicates the packet has been consumed by the hook.
187 */
188static inline int nf_hook_thresh(int pf, unsigned int hook,
189 struct sk_buff **pskb,
190 struct net_device *indev,
191 struct net_device *outdev,
192 int (*okfn)(struct sk_buff *), int thresh,
193 int cond)
194{
195 if (!cond)
196 return 1;
197#ifndef CONFIG_NETFILTER_DEBUG
198 if (list_empty(&nf_hooks[pf][hook]))
199 return 1;
200#endif
201 return nf_hook_slow(pf, hook, pskb, indev, outdev, okfn, thresh);
202}
203
204static inline int nf_hook(int pf, unsigned int hook, struct sk_buff **pskb,
205 struct net_device *indev, struct net_device *outdev,
206 int (*okfn)(struct sk_buff *))
207{
208 return nf_hook_thresh(pf, hook, pskb, indev, outdev, okfn, INT_MIN, 1);
209}
210
211/* Activate hook; either okfn or kfree_skb called, unless a hook
212 returns NF_STOLEN (in which case, it's up to the hook to deal with
213 the consequences).
214
215 Returns -ERRNO if packet dropped. Zero means queued, stolen or
216 accepted.
217*/
218
219/* RR:
220 > I don't want nf_hook to return anything because people might forget
221 > about async and trust the return value to mean "packet was ok".
222
223 AK:
224 Just document it clearly, then you can expect some sense from kernel
225 coders :)
226*/
227
228/* This is gross, but inline doesn't cut it for avoiding the function
229 call in fast path: gcc doesn't inline (needs value tracking?). --RR */
230
231/* HX: It's slightly less gross now. */
232
233#define NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, thresh) \
234({int __ret; \
235if ((__ret=nf_hook_thresh(pf, hook, &(skb), indev, outdev, okfn, thresh, 1)) == 1)\
236 __ret = (okfn)(skb); \
237__ret;})
238
239#define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) \
240({int __ret; \
241if ((__ret=nf_hook_thresh(pf, hook, &(skb), indev, outdev, okfn, INT_MIN, cond)) == 1)\
242 __ret = (okfn)(skb); \
243__ret;})
244
245#define NF_HOOK(pf, hook, skb, indev, outdev, okfn) \
246 NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, INT_MIN)
247
248/* Call setsockopt() */
249int nf_setsockopt(struct sock *sk, int pf, int optval, char __user *opt,
250 int len);
251int nf_getsockopt(struct sock *sk, int pf, int optval, char __user *opt,
252 int *len);
253
254int compat_nf_setsockopt(struct sock *sk, int pf, int optval,
255 char __user *opt, int len);
256int compat_nf_getsockopt(struct sock *sk, int pf, int optval,
257 char __user *opt, int *len);
258
259/* Packet queuing */
260struct nf_queue_handler {
261 int (*outfn)(struct sk_buff *skb, struct nf_info *info,
262 unsigned int queuenum, void *data);
263 void *data;
264 char *name;
265};
266extern int nf_register_queue_handler(int pf,
267 struct nf_queue_handler *qh);
268extern int nf_unregister_queue_handler(int pf);
269extern void nf_unregister_queue_handlers(struct nf_queue_handler *qh);
270extern void nf_reinject(struct sk_buff *skb,
271 struct nf_info *info,
272 unsigned int verdict);
273
274extern void (*ip_ct_attach)(struct sk_buff *, struct sk_buff *);
275extern void nf_ct_attach(struct sk_buff *, struct sk_buff *);
276
277/* FIXME: Before cache is ever used, this must be implemented for real. */
278extern void nf_invalidate_cache(int pf);
279
280/* Call this before modifying an existing packet: ensures it is
281 modifiable and linear to the point you care about (writable_len).
282 Returns true or false. */
283extern int skb_make_writable(struct sk_buff **pskb, unsigned int writable_len);
284
285struct nf_afinfo {
286 unsigned short family;
287 unsigned int (*checksum)(struct sk_buff *skb, unsigned int hook,
288 unsigned int dataoff, u_int8_t protocol);
289 void (*saveroute)(const struct sk_buff *skb,
290 struct nf_info *info);
291 int (*reroute)(struct sk_buff **skb,
292 const struct nf_info *info);
293 int route_key_size;
294};
295
296extern struct nf_afinfo *nf_afinfo[];
297static inline struct nf_afinfo *nf_get_afinfo(unsigned short family)
298{
299 return rcu_dereference(nf_afinfo[family]);
300}
301
302static inline unsigned int
303nf_checksum(struct sk_buff *skb, unsigned int hook, unsigned int dataoff,
304 u_int8_t protocol, unsigned short family)
305{
306 struct nf_afinfo *afinfo;
307 unsigned int csum = 0;
308
309 rcu_read_lock();
310 afinfo = nf_get_afinfo(family);
311 if (afinfo)
312 csum = afinfo->checksum(skb, hook, dataoff, protocol);
313 rcu_read_unlock();
314 return csum;
315}
316
317extern int nf_register_afinfo(struct nf_afinfo *afinfo);
318extern void nf_unregister_afinfo(struct nf_afinfo *afinfo);
319
320#define nf_info_reroute(x) ((void *)x + sizeof(struct nf_info))
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, int family)
327{
328#ifdef CONFIG_IP_NF_NAT_NEEDED
329 void (*decodefn)(struct sk_buff *, struct flowi *);
330
331 if (family == AF_INET && (decodefn = ip_nat_decode_session) != NULL)
332 decodefn(skb, fl);
333#endif
334}
335
336#ifdef CONFIG_PROC_FS
337#include <linux/proc_fs.h>
338extern struct proc_dir_entry *proc_net_netfilter;
339#endif
340
341#else /* !CONFIG_NETFILTER */
342#define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb)
343#define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) (okfn)(skb)
344static inline int nf_hook_thresh(int pf, unsigned int hook,
345 struct sk_buff **pskb,
346 struct net_device *indev,
347 struct net_device *outdev,
348 int (*okfn)(struct sk_buff *), int thresh,
349 int cond)
350{
351 return okfn(*pskb);
352}
353static inline int nf_hook(int pf, unsigned int hook, struct sk_buff **pskb,
354 struct net_device *indev, struct net_device *outdev,
355 int (*okfn)(struct sk_buff *))
356{
357 return 1;
358}
359static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {}
360struct flowi;
361static inline void
362nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, int family) {}
363#endif /*CONFIG_NETFILTER*/
364
365#endif /*__KERNEL__*/
366#endif /*__LINUX_NETFILTER_H*/