1 /*
2 * 25-Jul-1998 Major changes to allow for ip chain table
3 *
4 * 3-Jan-2000 Named tables to allow packet selection for different uses.
5 */
6
7 /*
8 * Format of an IP firewall descriptor
9 *
10 * src, dst, src_mask, dst_mask are always stored in network byte order.
11 * flags are stored in host byte order (of course).
12 * Port numbers are stored in HOST byte order.
13 */
14
15 #ifndef _IPTABLES_H
16 #define _IPTABLES_H
17
18 #ifdef __KERNEL__
19 #include <linux/if.h>
20 #include <linux/types.h>
21 #include <linux/in.h>
22 #include <linux/ip.h>
23 #include <linux/skbuff.h>
24 #endif
25 #include <linux/compiler.h>
26 #include <linux/netfilter_ipv4.h>
27
28 #define IPT_FUNCTION_MAXNAMELEN 30
29 #define IPT_TABLE_MAXNAMELEN 32
30
31 /* Yes, Virginia, you have to zero the padding. */
32 struct ipt_ip {
33 /* Source and destination IP addr */
34 struct in_addr src, dst;
35 /* Mask for src and dest IP addr */
36 struct in_addr smsk, dmsk;
37 char iniface[IFNAMSIZ], outiface[IFNAMSIZ];
38 unsigned char iniface_mask[IFNAMSIZ], outiface_mask[IFNAMSIZ];
39
40 /* Protocol, 0 = ANY */
41 u_int16_t proto;
42
43 /* Flags word */
44 u_int8_t flags;
45 /* Inverse flags */
46 u_int8_t invflags;
47 };
48
49 struct ipt_entry_match
50 {
51 union {
52 struct {
53 u_int16_t match_size;
54
55 /* Used by userspace */
56 char name[IPT_FUNCTION_MAXNAMELEN-1];
57
58 u_int8_t revision;
59 } user;
60 struct {
61 u_int16_t match_size;
62
63 /* Used inside the kernel */
64 struct ipt_match *match;
65 } kernel;
66
67 /* Total length */
68 u_int16_t match_size;
69 } u;
70
71 unsigned char data[0];
72 };
73
74 struct ipt_entry_target
75 {
76 union {
77 struct {
78 u_int16_t target_size;
79
80 /* Used by userspace */
81 char name[IPT_FUNCTION_MAXNAMELEN-1];
82
83 u_int8_t revision;
84 } user;
85 struct {
86 u_int16_t target_size;
87
88 /* Used inside the kernel */
89 struct ipt_target *target;
90 } kernel;
91
92 /* Total length */
93 u_int16_t target_size;
94 } u;
95
96 unsigned char data[0];
97 };
98
99 struct ipt_standard_target
100 {
101 struct ipt_entry_target target;
102 int verdict;
103 };
104
105 struct ipt_counters
106 {
107 u_int64_t pcnt, bcnt; /* Packet and byte counters */
108 };
109
110 /* Values for "flag" field in struct ipt_ip (general ip structure). */
111 #define IPT_F_FRAG 0x01 /* Set if rule is a fragment rule */
112 #define IPT_F_MASK 0x01 /* All possible flag bits mask. */
113
114 /* Values for "inv" field in struct ipt_ip. */
115 #define IPT_INV_VIA_IN 0x01 /* Invert the sense of IN IFACE. */
116 #define IPT_INV_VIA_OUT 0x02 /* Invert the sense of OUT IFACE */
117 #define IPT_INV_TOS 0x04 /* Invert the sense of TOS. */
118 #define IPT_INV_SRCIP 0x08 /* Invert the sense of SRC IP. */
119 #define IPT_INV_DSTIP 0x10 /* Invert the sense of DST OP. */
120 #define IPT_INV_FRAG 0x20 /* Invert the sense of FRAG. */
121 #define IPT_INV_PROTO 0x40 /* Invert the sense of PROTO. */
122 #define IPT_INV_MASK 0x7F /* All possible flag bits mask. */
123
124 /* This structure defines each of the firewall rules. Consists of 3
125 parts which are 1) general IP header stuff 2) match specific
126 stuff 3) the target to perform if the rule matches */
127 struct ipt_entry
128 {
129 struct ipt_ip ip;
130
131 /* Mark with fields that we care about. */
132 unsigned int nfcache;
133
134 /* Size of ipt_entry + matches */
135 u_int16_t target_offset;
136 /* Size of ipt_entry + matches + target */
137 u_int16_t next_offset;
138
139 /* Back pointer */
140 unsigned int comefrom;
141
142 /* Packet and byte counters. */
143 struct ipt_counters counters;
144
145 /* The matches (if any), then the target. */
146 unsigned char elems[0];
147 };
148
149 /*
150 * New IP firewall options for [gs]etsockopt at the RAW IP level.
151 * Unlike BSD Linux inherits IP options so you don't have to use a raw
152 * socket for this. Instead we check rights in the calls. */
153 #define IPT_BASE_CTL 64 /* base for firewall socket options */
154
155 #define IPT_SO_SET_REPLACE (IPT_BASE_CTL)
156 #define IPT_SO_SET_ADD_COUNTERS (IPT_BASE_CTL + 1)
157 #define IPT_SO_SET_MAX IPT_SO_SET_ADD_COUNTERS
158
159 #define IPT_SO_GET_INFO (IPT_BASE_CTL)
160 #define IPT_SO_GET_ENTRIES (IPT_BASE_CTL + 1)
161 #define IPT_SO_GET_REVISION_MATCH (IPT_BASE_CTL + 2)
162 #define IPT_SO_GET_REVISION_TARGET (IPT_BASE_CTL + 3)
163 #define IPT_SO_GET_MAX IPT_SO_GET_REVISION_TARGET
164
165 /* CONTINUE verdict for targets */
166 #define IPT_CONTINUE 0xFFFFFFFF
167
168 /* For standard target */
169 #define IPT_RETURN (-NF_MAX_VERDICT - 1)
170
171 /* TCP matching stuff */
172 struct ipt_tcp
173 {
174 u_int16_t spts[2]; /* Source port range. */
175 u_int16_t dpts[2]; /* Destination port range. */
176 u_int8_t option; /* TCP Option iff non-zero*/
177 u_int8_t flg_mask; /* TCP flags mask byte */
178 u_int8_t flg_cmp; /* TCP flags compare byte */
179 u_int8_t invflags; /* Inverse flags */
180 };
181
182 /* Values for "inv" field in struct ipt_tcp. */
183 #define IPT_TCP_INV_SRCPT 0x01 /* Invert the sense of source ports. */
184 #define IPT_TCP_INV_DSTPT 0x02 /* Invert the sense of dest ports. */
185 #define IPT_TCP_INV_FLAGS 0x04 /* Invert the sense of TCP flags. */
186 #define IPT_TCP_INV_OPTION 0x08 /* Invert the sense of option test. */
187 #define IPT_TCP_INV_MASK 0x0F /* All possible flags. */
188
189 /* UDP matching stuff */
190 struct ipt_udp
191 {
192 u_int16_t spts[2]; /* Source port range. */
193 u_int16_t dpts[2]; /* Destination port range. */
194 u_int8_t invflags; /* Inverse flags */
195 };
196
197 /* Values for "invflags" field in struct ipt_udp. */
198 #define IPT_UDP_INV_SRCPT 0x01 /* Invert the sense of source ports. */
199 #define IPT_UDP_INV_DSTPT 0x02 /* Invert the sense of dest ports. */
200 #define IPT_UDP_INV_MASK 0x03 /* All possible flags. */
201
202 /* ICMP matching stuff */
203 struct ipt_icmp
204 {
205 u_int8_t type; /* type to match */
206 u_int8_t code[2]; /* range of code */
207 u_int8_t invflags; /* Inverse flags */
208 };
209
210 /* Values for "inv" field for struct ipt_icmp. */
211 #define IPT_ICMP_INV 0x01 /* Invert the sense of type/code test */
212
213 /* The argument to IPT_SO_GET_INFO */
214 struct ipt_getinfo
215 {
216 /* Which table: caller fills this in. */
217 char name[IPT_TABLE_MAXNAMELEN];
218
219 /* Kernel fills these in. */
220 /* Which hook entry points are valid: bitmask */
221 unsigned int valid_hooks;
222
223 /* Hook entry points: one per netfilter hook. */
224 unsigned int hook_entry[NF_IP_NUMHOOKS];
225
226 /* Underflow points. */
227 unsigned int underflow[NF_IP_NUMHOOKS];
228
229 /* Number of entries */
230 unsigned int num_entries;
231
232 /* Size of entries. */
233 unsigned int size;
234 };
235
236 /* The argument to IPT_SO_SET_REPLACE. */
237 struct ipt_replace
238 {
239 /* Which table. */
240 char name[IPT_TABLE_MAXNAMELEN];
241
242 /* Which hook entry points are valid: bitmask. You can't
243 change this. */
244 unsigned int valid_hooks;
245
246 /* Number of entries */
247 unsigned int num_entries;
248
249 /* Total size of new entries */
250 unsigned int size;
251
252 /* Hook entry points. */
253 unsigned int hook_entry[NF_IP_NUMHOOKS];
254
255 /* Underflow points. */
256 unsigned int underflow[NF_IP_NUMHOOKS];
257
258 /* Information about old entries: */
259 /* Number of counters (must be equal to current number of entries). */
260 unsigned int num_counters;
261 /* The old entries' counters. */
262 struct ipt_counters __user *counters;
263
264 /* The entries (hang off end: not really an array). */
265 struct ipt_entry entries[0];
266 };
267
268 /* The argument to IPT_SO_ADD_COUNTERS. */
269 struct ipt_counters_info
270 {
271 /* Which table. */
272 char name[IPT_TABLE_MAXNAMELEN];
273
274 unsigned int num_counters;
275
276 /* The counters (actually `number' of these). */
277 struct ipt_counters counters[0];
278 };
279
280 /* The argument to IPT_SO_GET_ENTRIES. */
281 struct ipt_get_entries
282 {
283 /* Which table: user fills this in. */
284 char name[IPT_TABLE_MAXNAMELEN];
285
286 /* User fills this in: total entry size. */
287 unsigned int size;
288
289 /* The entries. */
290 struct ipt_entry entrytable[0];
291 };
292
293 /* The argument to IPT_SO_GET_REVISION_*. Returns highest revision
294 * kernel supports, if >= revision. */
295 struct ipt_get_revision
296 {
297 char name[IPT_FUNCTION_MAXNAMELEN-1];
298
299 u_int8_t revision;
300 };
301
302 /* Standard return verdict, or do jump. */
303 #define IPT_STANDARD_TARGET ""
304 /* Error verdict. */
305 #define IPT_ERROR_TARGET "ERROR"
306
307 /* Helper functions */
308 static __inline__ struct ipt_entry_target *
309 ipt_get_target(struct ipt_entry *e)
310 {
311 return (void *)e + e->target_offset;
312 }
313
314 /* fn returns 0 to continue iteration */
315 #define IPT_MATCH_ITERATE(e, fn, args...) \
316 ({ \
317 unsigned int __i; \
318 int __ret = 0; \
319 struct ipt_entry_match *__match; \
320 \
321 for (__i = sizeof(struct ipt_entry); \
322 __i < (e)->target_offset; \
323 __i += __match->u.match_size) { \
324 __match = (void *)(e) + __i; \
325 \
326 __ret = fn(__match , ## args); \
327 if (__ret != 0) \
328 break; \
329 } \
330 __ret; \
331 })
332
333 /* fn returns 0 to continue iteration */
334 #define IPT_ENTRY_ITERATE(entries, size, fn, args...) \
335 ({ \
336 unsigned int __i; \
337 int __ret = 0; \
338 struct ipt_entry *__entry; \
339 \
340 for (__i = 0; __i < (size); __i += __entry->next_offset) { \
341 __entry = (void *)(entries) + __i; \
342 \
343 __ret = fn(__entry , ## args); \
344 if (__ret != 0) \
345 break; \
346 } \
347 __ret; \
348 })
349
350 /*
351 * Main firewall chains definitions and global var's definitions.
352 */
353 #ifdef __KERNEL__
354
355 #include <linux/init.h>
356 extern void ipt_init(void) __init;
357
358 struct ipt_match
359 {
360 struct list_head list;
361
362 const char name[IPT_FUNCTION_MAXNAMELEN-1];
363
364 u_int8_t revision;
365
366 /* Return true or false: return FALSE and set *hotdrop = 1 to
367 force immediate packet drop. */
368 /* Arguments changed since 2.4, as this must now handle
369 non-linear skbs, using skb_copy_bits and
370 skb_ip_make_writable. */
371 int (*match)(const struct sk_buff *skb,
372 const struct net_device *in,
373 const struct net_device *out,
374 const void *matchinfo,
375 int offset,
376 int *hotdrop);
377
378 /* Called when user tries to insert an entry of this type. */
379 /* Should return true or false. */
380 int (*checkentry)(const char *tablename,
381 const struct ipt_ip *ip,
382 void *matchinfo,
383 unsigned int matchinfosize,
384 unsigned int hook_mask);
385
386 /* Called when entry of this type deleted. */
387 void (*destroy)(void *matchinfo, unsigned int matchinfosize);
388
389 /* Set this to THIS_MODULE. */
390 struct module *me;
391 };
392
393 /* Registration hooks for targets. */
394 struct ipt_target
395 {
396 struct list_head list;
397
398 const char name[IPT_FUNCTION_MAXNAMELEN-1];
399
400 u_int8_t revision;
401
402 /* Called when user tries to insert an entry of this type:
403 hook_mask is a bitmask of hooks from which it can be
404 called. */
405 /* Should return true or false. */
406 int (*checkentry)(const char *tablename,
407 const struct ipt_entry *e,
408 void *targinfo,
409 unsigned int targinfosize,
410 unsigned int hook_mask);
411
412 /* Called when entry of this type deleted. */
413 void (*destroy)(void *targinfo, unsigned int targinfosize);
414
415 /* Returns verdict. Argument order changed since 2.4, as this
416 must now handle non-linear skbs, using skb_copy_bits and
417 skb_ip_make_writable. */
418 unsigned int (*target)(struct sk_buff **pskb,
419 const struct net_device *in,
420 const struct net_device *out,
421 unsigned int hooknum,
422 const void *targinfo,
423 void *userdata);
424
425 /* Set this to THIS_MODULE. */
426 struct module *me;
427 };
428
429 extern int ipt_register_target(struct ipt_target *target);
430 extern void ipt_unregister_target(struct ipt_target *target);
431
432 extern int ipt_register_match(struct ipt_match *match);
433 extern void ipt_unregister_match(struct ipt_match *match);
434
435 /* Furniture shopping... */
436 struct ipt_table
437 {
438 struct list_head list;
439
440 /* A unique name... */
441 char name[IPT_TABLE_MAXNAMELEN];
442
443 /* What hooks you will enter on */
444 unsigned int valid_hooks;
445
446 /* Lock for the curtain */
447 rwlock_t lock;
448
449 /* Man behind the curtain... */
450 struct ipt_table_info *private;
451
452 /* Set to THIS_MODULE. */
453 struct module *me;
454 };
455
456 /* net/sched/ipt.c: Gimme access to your targets! Gets target->me. */
457 extern struct ipt_target *ipt_find_target(const char *name, u8 revision);
458
459 /* Standard entry. */
460 struct ipt_standard
461 {
462 struct ipt_entry entry;
463 struct ipt_standard_target target;
464 };
465
466 struct ipt_error_target
467 {
468 struct ipt_entry_target target;
469 char errorname[IPT_FUNCTION_MAXNAMELEN];
470 };
471
472 struct ipt_error
473 {
474 struct ipt_entry entry;
475 struct ipt_error_target target;
476 };
477
478 extern int ipt_register_table(struct ipt_table *table,
479 const struct ipt_replace *repl);
480 extern void ipt_unregister_table(struct ipt_table *table);
481 extern unsigned int ipt_do_table(struct sk_buff **pskb,
482 unsigned int hook,
483 const struct net_device *in,
484 const struct net_device *out,
485 struct ipt_table *table,
486 void *userdata);
487
488 #define IPT_ALIGN(s) (((s) + (__alignof__(struct ipt_entry)-1)) & ~(__alignof__(struct ipt_entry)-1))
489 #endif /*__KERNEL__*/
490 #endif /* _IPTABLES_H */
491
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