1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
|
#ifndef _X_TABLES_H
#define _X_TABLES_H
#define XT_FUNCTION_MAXNAMELEN 30
#define XT_TABLE_MAXNAMELEN 32
struct xt_entry_match
{
union {
struct {
u_int16_t match_size;
/* Used by userspace */
char name[XT_FUNCTION_MAXNAMELEN-1];
u_int8_t revision;
} user;
struct {
u_int16_t match_size;
/* Used inside the kernel */
struct xt_match *match;
} kernel;
/* Total length */
u_int16_t match_size;
} u;
unsigned char data[0];
};
struct xt_entry_target
{
union {
struct {
u_int16_t target_size;
/* Used by userspace */
char name[XT_FUNCTION_MAXNAMELEN-1];
u_int8_t revision;
} user;
struct {
u_int16_t target_size;
/* Used inside the kernel */
struct xt_target *target;
} kernel;
/* Total length */
u_int16_t target_size;
} u;
unsigned char data[0];
};
#define XT_TARGET_INIT(__name, __size) \
{ \
.target.u.user = { \
.target_size = XT_ALIGN(__size), \
.name = __name, \
}, \
}
struct xt_standard_target
{
struct xt_entry_target target;
int verdict;
};
/* The argument to IPT_SO_GET_REVISION_*. Returns highest revision
* kernel supports, if >= revision. */
struct xt_get_revision
{
char name[XT_FUNCTION_MAXNAMELEN-1];
u_int8_t revision;
};
/* CONTINUE verdict for targets */
#define XT_CONTINUE 0xFFFFFFFF
/* For standard target */
#define XT_RETURN (-NF_REPEAT - 1)
/* this is a dummy structure to find out the alignment requirement for a struct
* containing all the fundamental data types that are used in ipt_entry,
* ip6t_entry and arpt_entry. This sucks, and it is a hack. It will be my
* personal pleasure to remove it -HW
*/
struct _xt_align
{
u_int8_t u8;
u_int16_t u16;
u_int32_t u32;
u_int64_t u64;
};
#define XT_ALIGN(s) (((s) + (__alignof__(struct _xt_align)-1)) \
& ~(__alignof__(struct _xt_align)-1))
/* Standard return verdict, or do jump. */
#define XT_STANDARD_TARGET ""
/* Error verdict. */
#define XT_ERROR_TARGET "ERROR"
#define SET_COUNTER(c,b,p) do { (c).bcnt = (b); (c).pcnt = (p); } while(0)
#define ADD_COUNTER(c,b,p) do { (c).bcnt += (b); (c).pcnt += (p); } while(0)
struct xt_counters
{
u_int64_t pcnt, bcnt; /* Packet and byte counters */
};
/* The argument to IPT_SO_ADD_COUNTERS. */
struct xt_counters_info
{
/* Which table. */
char name[XT_TABLE_MAXNAMELEN];
unsigned int num_counters;
/* The counters (actually `number' of these). */
struct xt_counters counters[0];
};
#define XT_INV_PROTO 0x40 /* Invert the sense of PROTO. */
/* fn returns 0 to continue iteration */
#define XT_MATCH_ITERATE(type, e, fn, args...) \
({ \
unsigned int __i; \
int __ret = 0; \
struct xt_entry_match *__m; \
\
for (__i = sizeof(type); \
__i < (e)->target_offset; \
__i += __m->u.match_size) { \
__m = (void *)e + __i; \
\
__ret = fn(__m , ## args); \
if (__ret != 0) \
break; \
} \
__ret; \
})
/* fn returns 0 to continue iteration */
#define XT_ENTRY_ITERATE_CONTINUE(type, entries, size, n, fn, args...) \
({ \
unsigned int __i, __n; \
int __ret = 0; \
type *__entry; \
\
for (__i = 0, __n = 0; __i < (size); \
__i += __entry->next_offset, __n++) { \
__entry = (void *)(entries) + __i; \
if (__n < n) \
continue; \
\
__ret = fn(__entry , ## args); \
if (__ret != 0) \
break; \
} \
__ret; \
})
/* fn returns 0 to continue iteration */
#define XT_ENTRY_ITERATE(type, entries, size, fn, args...) \
XT_ENTRY_ITERATE_CONTINUE(type, entries, size, 0, fn, args)
#ifdef __KERNEL__
#include <linux/netdevice.h>
/**
* struct xt_match_param - parameters for match extensions' match functions
*
* @in: input netdevice
* @out: output netdevice
* @match: struct xt_match through which this function was invoked
* @matchinfo: per-match data
* @fragoff: packet is a fragment, this is the data offset
* @thoff: position of transport header relative to skb->data
* @hotdrop: drop packet if we had inspection problems
* @family: Actual NFPROTO_* through which the function is invoked
* (helpful when match->family == NFPROTO_UNSPEC)
*/
struct xt_match_param {
const struct net_device *in, *out;
const struct xt_match *match;
const void *matchinfo;
int fragoff;
unsigned int thoff;
bool *hotdrop;
u_int8_t family;
};
/**
* struct xt_mtchk_param - parameters for match extensions'
* checkentry functions
*
* @table: table the rule is tried to be inserted into
* @entryinfo: the family-specific rule data
* (struct ipt_ip, ip6t_ip, ebt_entry)
* @match: struct xt_match through which this function was invoked
* @matchinfo: per-match data
* @hook_mask: via which hooks the new rule is reachable
*/
struct xt_mtchk_param {
const char *table;
const void *entryinfo;
const struct xt_match *match;
void *matchinfo;
unsigned int hook_mask;
u_int8_t family;
};
/* Match destructor parameters */
struct xt_mtdtor_param {
const struct xt_match *match;
void *matchinfo;
u_int8_t family;
};
/**
* struct xt_target_param - parameters for target extensions' target functions
*
* @hooknum: hook through which this target was invoked
* @target: struct xt_target through which this function was invoked
* @targinfo: per-target data
*
* Other fields see above.
*/
struct xt_target_param {
const struct net_device *in, *out;
unsigned int hooknum;
const struct xt_target *target;
const void *targinfo;
u_int8_t family;
};
/**
* struct xt_tgchk_param - parameters for target extensions'
* checkentry functions
*
* @entryinfo: the family-specific rule data
* (struct ipt_entry, ip6t_entry, arpt_entry, ebt_entry)
*
* Other fields see above.
*/
struct xt_tgchk_param {
const char *table;
const void *entryinfo;
const struct xt_target *target;
void *targinfo;
unsigned int hook_mask;
u_int8_t family;
};
/* Target destructor parameters */
struct xt_tgdtor_param {
const struct xt_target *target;
void *targinfo;
u_int8_t family;
};
struct xt_match
{
struct list_head list;
const char name[XT_FUNCTION_MAXNAMELEN-1];
u_int8_t revision;
/* Return true or false: return FALSE and set *hotdrop = 1 to
force immediate packet drop. */
/* Arguments changed since 2.6.9, as this must now handle
non-linear skb, using skb_header_pointer and
skb_ip_make_writable. */
bool (*match)(const struct sk_buff *skb,
const struct xt_match_param *);
/* Called when user tries to insert an entry of this type. */
bool (*checkentry)(const struct xt_mtchk_param *);
/* Called when entry of this type deleted. */
void (*destroy)(const struct xt_mtdtor_param *);
/* Called when userspace align differs from kernel space one */
void (*compat_from_user)(void *dst, void *src);
int (*compat_to_user)(void __user *dst, void *src);
/* Set this to THIS_MODULE if you are a module, otherwise NULL */
struct module *me;
/* Free to use by each match */
unsigned long data;
const char *table;
unsigned int matchsize;
unsigned int compatsize;
unsigned int hooks;
unsigned short proto;
unsigned short family;
};
/* Registration hooks for targets. */
struct xt_target
{
struct list_head list;
const char name[XT_FUNCTION_MAXNAMELEN-1];
/* Returns verdict. Argument order changed since 2.6.9, as this
must now handle non-linear skbs, using skb_copy_bits and
skb_ip_make_writable. */
unsigned int (*target)(struct sk_buff *skb,
const struct xt_target_param *);
/* Called when user tries to insert an entry of this type:
hook_mask is a bitmask of hooks from which it can be
called. */
/* Should return true or false. */
bool (*checkentry)(const struct xt_tgchk_param *);
/* Called when entry of this type deleted. */
void (*destroy)(const struct xt_tgdtor_param *);
/* Called when userspace align differs from kernel space one */
void (*compat_from_user)(void *dst, void *src);
int (*compat_to_user)(void __user *dst, void *src);
/* Set this to THIS_MODULE if you are a module, otherwise NULL */
struct module *me;
const char *table;
unsigned int targetsize;
unsigned int compatsize;
unsigned int hooks;
unsigned short proto;
unsigned short family;
u_int8_t revision;
};
/* Furniture shopping... */
struct xt_table
{
struct list_head list;
/* What hooks you will enter on */
unsigned int valid_hooks;
/* Lock for the curtain */
struct mutex lock;
/* Man behind the curtain... */
struct xt_table_info *private;
/* Set this to THIS_MODULE if you are a module, otherwise NULL */
struct module *me;
u_int8_t af; /* address/protocol family */
/* A unique name... */
const char name[XT_TABLE_MAXNAMELEN];
};
#include <linux/netfilter_ipv4.h>
/* The table itself */
struct xt_table_info
{
/* Size per table */
unsigned int size;
/* Number of entries: FIXME. --RR */
unsigned int number;
/* Initial number of entries. Needed for module usage count */
unsigned int initial_entries;
/* Entry points and underflows */
unsigned int hook_entry[NF_INET_NUMHOOKS];
unsigned int underflow[NF_INET_NUMHOOKS];
/* ipt_entry tables: one per CPU */
/* Note : this field MUST be the last one, see XT_TABLE_INFO_SZ */
void *entries[1];
};
#define XT_TABLE_INFO_SZ (offsetof(struct xt_table_info, entries) \
+ nr_cpu_ids * sizeof(char *))
extern int xt_register_target(struct xt_target *target);
extern void xt_unregister_target(struct xt_target *target);
extern int xt_register_targets(struct xt_target *target, unsigned int n);
extern void xt_unregister_targets(struct xt_target *target, unsigned int n);
extern int xt_register_match(struct xt_match *target);
extern void xt_unregister_match(struct xt_match *target);
extern int xt_register_matches(struct xt_match *match, unsigned int n);
extern void xt_unregister_matches(struct xt_match *match, unsigned int n);
extern int xt_check_match(struct xt_mtchk_param *,
unsigned int size, u_int8_t proto, bool inv_proto);
extern int xt_check_target(struct xt_tgchk_param *,
unsigned int size, u_int8_t proto, bool inv_proto);
extern struct xt_table *xt_register_table(struct net *net,
struct xt_table *table,
struct xt_table_info *bootstrap,
struct xt_table_info *newinfo);
extern void *xt_unregister_table(struct xt_table *table);
extern struct xt_table_info *xt_replace_table(struct xt_table *table,
unsigned int num_counters,
struct xt_table_info *newinfo,
int *error);
extern struct xt_match *xt_find_match(u8 af, const char *name, u8 revision);
extern struct xt_target *xt_find_target(u8 af, const char *name, u8 revision);
extern struct xt_target *xt_request_find_target(u8 af, const char *name,
u8 revision);
extern int xt_find_revision(u8 af, const char *name, u8 revision,
int target, int *err);
extern struct xt_table *xt_find_table_lock(struct net *net, u_int8_t af,
const char *name);
extern void xt_table_unlock(struct xt_table *t);
extern int xt_proto_init(struct net *net, u_int8_t af);
extern void xt_proto_fini(struct net *net, u_int8_t af);
extern struct xt_table_info *xt_alloc_table_info(unsigned int size);
extern void xt_free_table_info(struct xt_table_info *info);
extern void xt_table_entry_swap_rcu(struct xt_table_info *old,
struct xt_table_info *new);
/*
* This helper is performance critical and must be inlined
*/
static inline unsigned long ifname_compare_aligned(const char *_a,
const char *_b,
const char *_mask)
{
const unsigned long *a = (const unsigned long *)_a;
const unsigned long *b = (const unsigned long *)_b;
const unsigned long *mask = (const unsigned long *)_mask;
unsigned long ret;
ret = (a[0] ^ b[0]) & mask[0];
if (IFNAMSIZ > sizeof(unsigned long))
ret |= (a[1] ^ b[1]) & mask[1];
if (IFNAMSIZ > 2 * sizeof(unsigned long))
ret |= (a[2] ^ b[2]) & mask[2];
if (IFNAMSIZ > 3 * sizeof(unsigned long))
ret |= (a[3] ^ b[3]) & mask[3];
BUILD_BUG_ON(IFNAMSIZ > 4 * sizeof(unsigned long));
return ret;
}
#ifdef CONFIG_COMPAT
#include <net/compat.h>
struct compat_xt_entry_match
{
union {
struct {
u_int16_t match_size;
char name[XT_FUNCTION_MAXNAMELEN - 1];
u_int8_t revision;
} user;
struct {
u_int16_t match_size;
compat_uptr_t match;
} kernel;
u_int16_t match_size;
} u;
unsigned char data[0];
};
struct compat_xt_entry_target
{
union {
struct {
u_int16_t target_size;
char name[XT_FUNCTION_MAXNAMELEN - 1];
u_int8_t revision;
} user;
struct {
u_int16_t target_size;
compat_uptr_t target;
} kernel;
u_int16_t target_size;
} u;
unsigned char data[0];
};
/* FIXME: this works only on 32 bit tasks
* need to change whole approach in order to calculate align as function of
* current task alignment */
struct compat_xt_counters
{
#if defined(CONFIG_X86_64) || defined(CONFIG_IA64)
u_int32_t cnt[4];
#else
u_int64_t cnt[2];
#endif
};
struct compat_xt_counters_info
{
char name[XT_TABLE_MAXNAMELEN];
compat_uint_t num_counters;
struct compat_xt_counters counters[0];
};
#define COMPAT_XT_ALIGN(s) (((s) + (__alignof__(struct compat_xt_counters)-1)) \
& ~(__alignof__(struct compat_xt_counters)-1))
extern void xt_compat_lock(u_int8_t af);
extern void xt_compat_unlock(u_int8_t af);
extern int xt_compat_add_offset(u_int8_t af, unsigned int offset, short delta);
extern void xt_compat_flush_offsets(u_int8_t af);
extern short xt_compat_calc_jump(u_int8_t af, unsigned int offset);
extern int xt_compat_match_offset(const struct xt_match *match);
extern int xt_compat_match_from_user(struct xt_entry_match *m,
void **dstptr, unsigned int *size);
extern int xt_compat_match_to_user(struct xt_entry_match *m,
void __user **dstptr, unsigned int *size);
extern int xt_compat_target_offset(const struct xt_target *target);
extern void xt_compat_target_from_user(struct xt_entry_target *t,
void **dstptr, unsigned int *size);
extern int xt_compat_target_to_user(struct xt_entry_target *t,
void __user **dstptr, unsigned int *size);
#endif /* CONFIG_COMPAT */
#endif /* __KERNEL__ */
#endif /* _X_TABLES_H */
|