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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#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);
113
114/* Functions to register get/setsockopt ranges (non-inclusive). You
115 need to check permissions yourself! */
116int nf_register_sockopt(struct nf_sockopt_ops *reg);
117void nf_unregister_sockopt(struct nf_sockopt_ops *reg);
118
119extern struct list_head nf_hooks[NPROTO][NF_MAX_HOOKS];
120
121/* those NF_LOG_* defines and struct nf_loginfo are legacy definitios that will
122 * disappear once iptables is replaced with pkttables. Please DO NOT use them
123 * for any new code! */
124#define NF_LOG_TCPSEQ 0x01 /* Log TCP sequence numbers */
125#define NF_LOG_TCPOPT 0x02 /* Log TCP options */
126#define NF_LOG_IPOPT 0x04 /* Log IP options */
127#define NF_LOG_UID 0x08 /* Log UID owning local socket */
128#define NF_LOG_MASK 0x0f
129
130#define NF_LOG_TYPE_LOG 0x01
131#define NF_LOG_TYPE_ULOG 0x02
132
133struct nf_loginfo {
134 u_int8_t type;
135 union {
136 struct {
137 u_int32_t copy_len;
138 u_int16_t group;
139 u_int16_t qthreshold;
140 } ulog;
141 struct {
142 u_int8_t level;
143 u_int8_t logflags;
144 } log;
145 } u;
146};
147
148typedef void nf_logfn(unsigned int pf,
149 unsigned int hooknum,
150 const struct sk_buff *skb,
151 const struct net_device *in,
152 const struct net_device *out,
153 const struct nf_loginfo *li,
154 const char *prefix);
155
156struct nf_logger {
157 struct module *me;
158 nf_logfn *logfn;
159 char *name;
160};
161
162/* Function to register/unregister log function. */
163int nf_log_register(int pf, struct nf_logger *logger);
164int nf_log_unregister_pf(int pf);
165void nf_log_unregister_logger(struct nf_logger *logger);
166
167/* Calls the registered backend logging function */
168void nf_log_packet(int pf,
169 unsigned int hooknum,
170 const struct sk_buff *skb,
171 const struct net_device *in,
172 const struct net_device *out,
173 struct nf_loginfo *li,
174 const char *fmt, ...);
175
176int nf_hook_slow(int pf, unsigned int hook, struct sk_buff **pskb,
177 struct net_device *indev, struct net_device *outdev,
178 int (*okfn)(struct sk_buff *), int thresh);
179
180/**
181 * nf_hook_thresh - call a netfilter hook
182 *
183 * Returns 1 if the hook has allowed the packet to pass. The function
184 * okfn must be invoked by the caller in this case. Any other return
185 * value indicates the packet has been consumed by the hook.
186 */
187static inline int nf_hook_thresh(int pf, unsigned int hook,
188 struct sk_buff **pskb,
189 struct net_device *indev,
190 struct net_device *outdev,
191 int (*okfn)(struct sk_buff *), int thresh,
192 int cond)
193{
194 if (!cond)
195 return 1;
196#ifndef CONFIG_NETFILTER_DEBUG
197 if (list_empty(&nf_hooks[pf][hook]))
198 return 1;
199#endif
200 return nf_hook_slow(pf, hook, pskb, indev, outdev, okfn, thresh);
201}
202
203static inline int nf_hook(int pf, unsigned int hook, struct sk_buff **pskb,
204 struct net_device *indev, struct net_device *outdev,
205 int (*okfn)(struct sk_buff *))
206{
207 return nf_hook_thresh(pf, hook, pskb, indev, outdev, okfn, INT_MIN, 1);
208}
209
210/* Activate hook; either okfn or kfree_skb called, unless a hook
211 returns NF_STOLEN (in which case, it's up to the hook to deal with
212 the consequences).
213
214 Returns -ERRNO if packet dropped. Zero means queued, stolen or
215 accepted.
216*/
217
218/* RR:
219 > I don't want nf_hook to return anything because people might forget
220 > about async and trust the return value to mean "packet was ok".
221
222 AK:
223 Just document it clearly, then you can expect some sense from kernel
224 coders :)
225*/
226
227/* This is gross, but inline doesn't cut it for avoiding the function
228 call in fast path: gcc doesn't inline (needs value tracking?). --RR */
229
230/* HX: It's slightly less gross now. */
231
232#define NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, thresh) \
233({int __ret; \
234if ((__ret=nf_hook_thresh(pf, hook, &(skb), indev, outdev, okfn, thresh, 1)) == 1)\
235 __ret = (okfn)(skb); \
236__ret;})
237
238#define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) \
239({int __ret; \
240if ((__ret=nf_hook_thresh(pf, hook, &(skb), indev, outdev, okfn, INT_MIN, cond)) == 1)\
241 __ret = (okfn)(skb); \
242__ret;})
243
244#define NF_HOOK(pf, hook, skb, indev, outdev, okfn) \
245 NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, INT_MIN)
246
247/* Call setsockopt() */
248int nf_setsockopt(struct sock *sk, int pf, int optval, char __user *opt,
249 int len);
250int nf_getsockopt(struct sock *sk, int pf, int optval, char __user *opt,
251 int *len);
252
253int compat_nf_setsockopt(struct sock *sk, int pf, int optval,
254 char __user *opt, int len);
255int compat_nf_getsockopt(struct sock *sk, int pf, int optval,
256 char __user *opt, int *len);
257
258/* Packet queuing */
259struct nf_queue_handler {
260 int (*outfn)(struct sk_buff *skb, struct nf_info *info,
261 unsigned int queuenum, void *data);
262 void *data;
263 char *name;
264};
265extern int nf_register_queue_handler(int pf,
266 struct nf_queue_handler *qh);
267extern int nf_unregister_queue_handler(int pf);
268extern void nf_unregister_queue_handlers(struct nf_queue_handler *qh);
269extern void nf_reinject(struct sk_buff *skb,
270 struct nf_info *info,
271 unsigned int verdict);
272
273extern void (*ip_ct_attach)(struct sk_buff *, struct sk_buff *);
274extern void nf_ct_attach(struct sk_buff *, struct sk_buff *);
275
276/* FIXME: Before cache is ever used, this must be implemented for real. */
277extern void nf_invalidate_cache(int pf);
278
279/* Call this before modifying an existing packet: ensures it is
280 modifiable and linear to the point you care about (writable_len).
281 Returns true or false. */
282extern int skb_make_writable(struct sk_buff **pskb, unsigned int writable_len);
283
284struct nf_queue_rerouter {
285 void (*save)(const struct sk_buff *skb, struct nf_info *info);
286 int (*reroute)(struct sk_buff **skb, const struct nf_info *info);
287 int rer_size;
288};
289
290#define nf_info_reroute(x) ((void *)x + sizeof(struct nf_info))
291
292extern int nf_register_queue_rerouter(int pf, struct nf_queue_rerouter *rer);
293extern int nf_unregister_queue_rerouter(int pf);
294
295#include <net/flow.h>
296extern void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *);
297
298static inline void
299nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, int family)
300{
301#ifdef CONFIG_IP_NF_NAT_NEEDED
302 void (*decodefn)(struct sk_buff *, struct flowi *);
303
304 if (family == AF_INET && (decodefn = ip_nat_decode_session) != NULL)
305 decodefn(skb, fl);
306#endif
307}
308
309#ifdef CONFIG_PROC_FS
310#include <linux/proc_fs.h>
311extern struct proc_dir_entry *proc_net_netfilter;
312#endif
313
314#else /* !CONFIG_NETFILTER */
315#define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb)
316#define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) (okfn)(skb)
317static inline int nf_hook_thresh(int pf, unsigned int hook,
318 struct sk_buff **pskb,
319 struct net_device *indev,
320 struct net_device *outdev,
321 int (*okfn)(struct sk_buff *), int thresh,
322 int cond)
323{
324 return okfn(*pskb);
325}
326static inline int nf_hook(int pf, unsigned int hook, struct sk_buff **pskb,
327 struct net_device *indev, struct net_device *outdev,
328 int (*okfn)(struct sk_buff *))
329{
330 return 1;
331}
332static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {}
333struct flowi;
334static inline void
335nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, int family) {}
336#endif /*CONFIG_NETFILTER*/
337
338#endif /*__KERNEL__*/
339#endif /*__LINUX_NETFILTER_H*/