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#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
84 int get_optmin;
85 int get_optmax;
86 int (*get)(struct sock *sk, int optval, void __user *user, int *len);
87
88 /* Number of users inside set() or get(). */
89 unsigned int use;
90 struct task_struct *cleanup_task;
91};
92
93/* Each queued (to userspace) skbuff has one of these. */
94struct nf_info
95{
96 /* The ops struct which sent us to userspace. */
97 struct nf_hook_ops *elem;
98
99 /* If we're sent to userspace, this keeps housekeeping info */
100 int pf;
101 unsigned int hook;
102 struct net_device *indev, *outdev;
103 int (*okfn)(struct sk_buff *);
104};
105
106/* Function to register/unregister hook points. */
107int nf_register_hook(struct nf_hook_ops *reg);
108void nf_unregister_hook(struct nf_hook_ops *reg);
109
110/* Functions to register get/setsockopt ranges (non-inclusive). You
111 need to check permissions yourself! */
112int nf_register_sockopt(struct nf_sockopt_ops *reg);
113void nf_unregister_sockopt(struct nf_sockopt_ops *reg);
114
115extern struct list_head nf_hooks[NPROTO][NF_MAX_HOOKS];
116
117/* those NF_LOG_* defines and struct nf_loginfo are legacy definitios that will
118 * disappear once iptables is replaced with pkttables. Please DO NOT use them
119 * for any new code! */
120#define NF_LOG_TCPSEQ 0x01 /* Log TCP sequence numbers */
121#define NF_LOG_TCPOPT 0x02 /* Log TCP options */
122#define NF_LOG_IPOPT 0x04 /* Log IP options */
123#define NF_LOG_UID 0x08 /* Log UID owning local socket */
124#define NF_LOG_MASK 0x0f
125
126#define NF_LOG_TYPE_LOG 0x01
127#define NF_LOG_TYPE_ULOG 0x02
128
129struct nf_loginfo {
130 u_int8_t type;
131 union {
132 struct {
133 u_int32_t copy_len;
134 u_int16_t group;
135 u_int16_t qthreshold;
136 } ulog;
137 struct {
138 u_int8_t level;
139 u_int8_t logflags;
140 } log;
141 } u;
142};
143
144typedef void nf_logfn(unsigned int pf,
145 unsigned int hooknum,
146 const struct sk_buff *skb,
147 const struct net_device *in,
148 const struct net_device *out,
149 const struct nf_loginfo *li,
150 const char *prefix);
151
152struct nf_logger {
153 struct module *me;
154 nf_logfn *logfn;
155 char *name;
156};
157
158/* Function to register/unregister log function. */
159int nf_log_register(int pf, struct nf_logger *logger);
160int nf_log_unregister_pf(int pf);
161void nf_log_unregister_logger(struct nf_logger *logger);
162
163/* Calls the registered backend logging function */
164void nf_log_packet(int pf,
165 unsigned int hooknum,
166 const struct sk_buff *skb,
167 const struct net_device *in,
168 const struct net_device *out,
169 struct nf_loginfo *li,
170 const char *fmt, ...);
171
172int nf_hook_slow(int pf, unsigned int hook, struct sk_buff **pskb,
173 struct net_device *indev, struct net_device *outdev,
174 int (*okfn)(struct sk_buff *), int thresh);
175
176/**
177 * nf_hook_thresh - call a netfilter hook
178 *
179 * Returns 1 if the hook has allowed the packet to pass. The function
180 * okfn must be invoked by the caller in this case. Any other return
181 * value indicates the packet has been consumed by the hook.
182 */
183static inline int nf_hook_thresh(int pf, unsigned int hook,
184 struct sk_buff **pskb,
185 struct net_device *indev,
186 struct net_device *outdev,
187 int (*okfn)(struct sk_buff *), int thresh,
188 int cond)
189{
190 if (!cond)
191 return 1;
192#ifndef CONFIG_NETFILTER_DEBUG
193 if (list_empty(&nf_hooks[pf][hook]))
194 return 1;
195#endif
196 return nf_hook_slow(pf, hook, pskb, indev, outdev, okfn, thresh);
197}
198
199static inline int nf_hook(int pf, unsigned int hook, struct sk_buff **pskb,
200 struct net_device *indev, struct net_device *outdev,
201 int (*okfn)(struct sk_buff *))
202{
203 return nf_hook_thresh(pf, hook, pskb, indev, outdev, okfn, INT_MIN, 1);
204}
205
206/* Activate hook; either okfn or kfree_skb called, unless a hook
207 returns NF_STOLEN (in which case, it's up to the hook to deal with
208 the consequences).
209
210 Returns -ERRNO if packet dropped. Zero means queued, stolen or
211 accepted.
212*/
213
214/* RR:
215 > I don't want nf_hook to return anything because people might forget
216 > about async and trust the return value to mean "packet was ok".
217
218 AK:
219 Just document it clearly, then you can expect some sense from kernel
220 coders :)
221*/
222
223/* This is gross, but inline doesn't cut it for avoiding the function
224 call in fast path: gcc doesn't inline (needs value tracking?). --RR */
225
226/* HX: It's slightly less gross now. */
227
228#define NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, thresh) \
229({int __ret; \
230if ((__ret=nf_hook_thresh(pf, hook, &(skb), indev, outdev, okfn, thresh, 1)) == 1)\
231 __ret = (okfn)(skb); \
232__ret;})
233
234#define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) \
235({int __ret; \
236if ((__ret=nf_hook_thresh(pf, hook, &(skb), indev, outdev, okfn, INT_MIN, cond)) == 1)\
237 __ret = (okfn)(skb); \
238__ret;})
239
240#define NF_HOOK(pf, hook, skb, indev, outdev, okfn) \
241 NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, INT_MIN)
242
243/* Call setsockopt() */
244int nf_setsockopt(struct sock *sk, int pf, int optval, char __user *opt,
245 int len);
246int nf_getsockopt(struct sock *sk, int pf, int optval, char __user *opt,
247 int *len);
248
249/* Packet queuing */
250struct nf_queue_handler {
251 int (*outfn)(struct sk_buff *skb, struct nf_info *info,
252 unsigned int queuenum, void *data);
253 void *data;
254 char *name;
255};
256extern int nf_register_queue_handler(int pf,
257 struct nf_queue_handler *qh);
258extern int nf_unregister_queue_handler(int pf);
259extern void nf_unregister_queue_handlers(struct nf_queue_handler *qh);
260extern void nf_reinject(struct sk_buff *skb,
261 struct nf_info *info,
262 unsigned int verdict);
263
264extern void (*ip_ct_attach)(struct sk_buff *, struct sk_buff *);
265extern void nf_ct_attach(struct sk_buff *, struct sk_buff *);
266
267/* FIXME: Before cache is ever used, this must be implemented for real. */
268extern void nf_invalidate_cache(int pf);
269
270/* Call this before modifying an existing packet: ensures it is
271 modifiable and linear to the point you care about (writable_len).
272 Returns true or false. */
273extern int skb_make_writable(struct sk_buff **pskb, unsigned int writable_len);
274
275struct nf_queue_rerouter {
276 void (*save)(const struct sk_buff *skb, struct nf_info *info);
277 int (*reroute)(struct sk_buff **skb, const struct nf_info *info);
278 int rer_size;
279};
280
281#define nf_info_reroute(x) ((void *)x + sizeof(struct nf_info))
282
283extern int nf_register_queue_rerouter(int pf, struct nf_queue_rerouter *rer);
284extern int nf_unregister_queue_rerouter(int pf);
285
286#include <net/flow.h>
287extern void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *);
288
289static inline void
290nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, int family)
291{
292#ifdef CONFIG_IP_NF_NAT_NEEDED
293 void (*decodefn)(struct sk_buff *, struct flowi *);
294
295 if (family == AF_INET && (decodefn = ip_nat_decode_session) != NULL)
296 decodefn(skb, fl);
297#endif
298}
299
300#ifdef CONFIG_PROC_FS
301#include <linux/proc_fs.h>
302extern struct proc_dir_entry *proc_net_netfilter;
303#endif
304
305#else /* !CONFIG_NETFILTER */
306#define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb)
307#define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) (okfn)(skb)
308static inline int nf_hook_thresh(int pf, unsigned int hook,
309 struct sk_buff **pskb,
310 struct net_device *indev,
311 struct net_device *outdev,
312 int (*okfn)(struct sk_buff *), int thresh,
313 int cond)
314{
315 return okfn(*pskb);
316}
317static inline int nf_hook(int pf, unsigned int hook, struct sk_buff **pskb,
318 struct net_device *indev, struct net_device *outdev,
319 int (*okfn)(struct sk_buff *))
320{
321 return 1;
322}
323static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {}
324struct flowi;
325static inline void
326nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, int family) {}
327#endif /*CONFIG_NETFILTER*/
328
329#endif /*__KERNEL__*/
330#endif /*__LINUX_NETFILTER_H*/