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Tomato 1.25
[tomato.git] / release / src / linux / linux / net / ipv4 / netfilter / arp_tables.c
blob757fc2abf816059ab746a5cce780366cbe1408e3
1 /*
2 * Packet matching code for ARP packets.
3 *
4 * Based heavily, if not almost entirely, upon ip_tables.c framework.
5 *
6 * Some ARP specific bits are:
7 *
8 * Copyright (C) 2002 David S. Miller (davem@redhat.com)
9 *
10 */
11
12 #include <linux/config.h>
13 #include <linux/kernel.h>
14 #include <linux/skbuff.h>
15 #include <linux/netdevice.h>
16 #include <linux/if_arp.h>
17 #include <linux/kmod.h>
18 #include <linux/vmalloc.h>
19 #include <linux/proc_fs.h>
20 #include <linux/module.h>
21 #include <linux/init.h>
22
23 #include <asm/uaccess.h>
24 #include <asm/semaphore.h>
25
26 #include <linux/netfilter_arp/arp_tables.h>
27
28 /*#define DEBUG_ARP_TABLES*/
29 /*#define DEBUG_ARP_TABLES_USER*/
30
31 #ifdef DEBUG_ARP_TABLES
32 #define dprintf(format, args...) printk(format , ## args)
33 #else
34 #define dprintf(format, args...)
35 #endif
36
37 #ifdef DEBUG_ARP_TABLES_USER
38 #define duprintf(format, args...) printk(format , ## args)
39 #else
40 #define duprintf(format, args...)
41 #endif
42
43 #ifdef CONFIG_NETFILTER_DEBUG
44 #define ARP_NF_ASSERT(x) \
45 do { \
46 if (!(x)) \
47 printk("ARP_NF_ASSERT: %s:%s:%u\n", \
48 __FUNCTION__, __FILE__, __LINE__); \
49 } while(0)
50 #else
51 #define ARP_NF_ASSERT(x)
52 #endif
53 #define SMP_ALIGN(x) (((x) + SMP_CACHE_BYTES-1) & ~(SMP_CACHE_BYTES-1))
54
55 static DECLARE_MUTEX(arpt_mutex);
56
57 #define ASSERT_READ_LOCK(x) ARP_NF_ASSERT(down_trylock(&arpt_mutex) != 0)
58 #define ASSERT_WRITE_LOCK(x) ARP_NF_ASSERT(down_trylock(&arpt_mutex) != 0)
59 #include <linux/netfilter_ipv4/lockhelp.h>
60 #include <linux/netfilter_ipv4/listhelp.h>
61
62 struct arpt_table_info {
63 unsigned int size;
64 unsigned int number;
65 unsigned int initial_entries;
66 unsigned int hook_entry[NF_ARP_NUMHOOKS];
67 unsigned int underflow[NF_ARP_NUMHOOKS];
68 char entries[0] __attribute__((aligned(SMP_CACHE_BYTES)));
69 };
70
71 static LIST_HEAD(arpt_target);
72 static LIST_HEAD(arpt_tables);
73 #define ADD_COUNTER(c,b,p) do { (c).bcnt += (b); (c).pcnt += (p); } while(0)
74
75 #ifdef CONFIG_SMP
76 #define TABLE_OFFSET(t,p) (SMP_ALIGN((t)->size)*(p))
77 #else
78 #define TABLE_OFFSET(t,p) 0
79 #endif
80
81 static inline int arp_devaddr_compare(const struct arpt_devaddr_info *ap,
82 char *hdr_addr, int len)
83 {
84 int i, ret;
85
86 if (len > ARPT_DEV_ADDR_LEN_MAX)
87 len = ARPT_DEV_ADDR_LEN_MAX;
88
89 ret = 0;
90 for (i = 0; i < len; i++)
91 ret |= (hdr_addr[i] ^ ap->addr[i]) & ap->mask[i];
92
93 return (ret != 0);
94 }
95
96 /* Returns whether packet matches rule or not. */
97 static inline int arp_packet_match(const struct arphdr *arphdr,
98 struct net_device *dev,
99 const char *indev,
100 const char *outdev,
101 const struct arpt_arp *arpinfo)
102 {
103 char *arpptr = (char *)(arphdr + 1);
104 char *src_devaddr, *tgt_devaddr;
105 u32 *src_ipaddr, *tgt_ipaddr;
106 int i, ret;
107
108 #define FWINV(bool,invflg) ((bool) ^ !!(arpinfo->invflags & invflg))
109
110 if (FWINV((arphdr->ar_op & arpinfo->arpop_mask) != arpinfo->arpop,
111 ARPT_INV_ARPOP)) {
112 dprintf("ARP operation field mismatch.\n");
113 dprintf("ar_op: %04x info->arpop: %04x info->arpop_mask: %04x\n",
114 arphdr->ar_op, arpinfo->arpop, arpinfo->arpop_mask);
115 return 0;
116 }
117
118 if (FWINV((arphdr->ar_hrd & arpinfo->arhrd_mask) != arpinfo->arhrd,
119 ARPT_INV_ARPHRD)) {
120 dprintf("ARP hardware address format mismatch.\n");
121 dprintf("ar_hrd: %04x info->arhrd: %04x info->arhrd_mask: %04x\n",
122 arphdr->ar_hrd, arpinfo->arhrd, arpinfo->arhrd_mask);
123 return 0;
124 }
125
126 if (FWINV((arphdr->ar_pro & arpinfo->arpro_mask) != arpinfo->arpro,
127 ARPT_INV_ARPPRO)) {
128 dprintf("ARP protocol address format mismatch.\n");
129 dprintf("ar_pro: %04x info->arpro: %04x info->arpro_mask: %04x\n",
130 arphdr->ar_pro, arpinfo->arpro, arpinfo->arpro_mask);
131 return 0;
132 }
133
134 if (FWINV((arphdr->ar_hln & arpinfo->arhln_mask) != arpinfo->arhln,
135 ARPT_INV_ARPHLN)) {
136 dprintf("ARP hardware address length mismatch.\n");
137 dprintf("ar_hln: %02x info->arhln: %02x info->arhln_mask: %02x\n",
138 arphdr->ar_hln, arpinfo->arhln, arpinfo->arhln_mask);
139 }
140
141 src_devaddr = arpptr;
142 arpptr += dev->addr_len;
143 src_ipaddr = (u32 *) arpptr;
144 arpptr += sizeof(u32);
145 tgt_devaddr = arpptr;
146 arpptr += dev->addr_len;
147 tgt_ipaddr = (u32 *) arpptr;
148
149 if (FWINV(arp_devaddr_compare(&arpinfo->src_devaddr, src_devaddr, dev->addr_len),
150 ARPT_INV_SRCDEVADDR) ||
151 FWINV(arp_devaddr_compare(&arpinfo->tgt_devaddr, tgt_devaddr, dev->addr_len),
152 ARPT_INV_TGTDEVADDR)) {
153 dprintf("Source or target device address mismatch.\n");
154
155 return 0;
156 }
157
158 if (FWINV(((*src_ipaddr) & arpinfo->smsk.s_addr) != arpinfo->src.s_addr,
159 ARPT_INV_SRCIP) ||
160 FWINV((((*tgt_ipaddr) & arpinfo->tmsk.s_addr) != arpinfo->tgt.s_addr),
161 ARPT_INV_TGTIP)) {
162 dprintf("Source or target IP address mismatch.\n");
163
164 dprintf("SRC: %u.%u.%u.%u. Mask: %u.%u.%u.%u. Target: %u.%u.%u.%u.%s\n",
165 NIPQUAD(*src_ipaddr),
166 NIPQUAD(arpinfo->smsk.s_addr),
167 NIPQUAD(arpinfo->src.s_addr),
168 arpinfo->invflags & ARPT_INV_SRCIP ? " (INV)" : "");
169 dprintf("TGT: %u.%u.%u.%u Mask: %u.%u.%u.%u Target: %u.%u.%u.%u.%s\n",
170 NIPQUAD(*tgt_ipaddr),
171 NIPQUAD(arpinfo->tmsk.s_addr),
172 NIPQUAD(arpinfo->tgt.s_addr),
173 arpinfo->invflags & ARPT_INV_TGTIP ? " (INV)" : "");
174 return 0;
175 }
176
177 /* Look for ifname matches; this should unroll nicely. */
178 for (i = 0, ret = 0; i < IFNAMSIZ/sizeof(unsigned long); i++) {
179 ret |= (((const unsigned long *)indev)[i]
180 ^ ((const unsigned long *)arpinfo->iniface)[i])
181 & ((const unsigned long *)arpinfo->iniface_mask)[i];
182 }
183
184 if (FWINV(ret != 0, ARPT_INV_VIA_IN)) {
185 dprintf("VIA in mismatch (%s vs %s).%s\n",
186 indev, arpinfo->iniface,
187 arpinfo->invflags&ARPT_INV_VIA_IN ?" (INV)":"");
188 return 0;
189 }
190
191 for (i = 0, ret = 0; i < IFNAMSIZ/sizeof(unsigned long); i++) {
192 ret |= (((const unsigned long *)outdev)[i]
193 ^ ((const unsigned long *)arpinfo->outiface)[i])
194 & ((const unsigned long *)arpinfo->outiface_mask)[i];
195 }
196
197 if (FWINV(ret != 0, ARPT_INV_VIA_OUT)) {
198 dprintf("VIA out mismatch (%s vs %s).%s\n",
199 outdev, arpinfo->outiface,
200 arpinfo->invflags&ARPT_INV_VIA_OUT ?" (INV)":"");
201 return 0;
202 }
203
204 return 1;
205 }
206
207 static inline int arp_checkentry(const struct arpt_arp *arp)
208 {
209 if (arp->flags & ~ARPT_F_MASK) {
210 duprintf("Unknown flag bits set: %08X\n",
211 arp->flags & ~ARPT_F_MASK);
212 return 0;
213 }
214 if (arp->invflags & ~ARPT_INV_MASK) {
215 duprintf("Unknown invflag bits set: %08X\n",
216 arp->invflags & ~ARPT_INV_MASK);
217 return 0;
218 }
219
220 return 1;
221 }
222
223 static unsigned int arpt_error(struct sk_buff **pskb,
224 unsigned int hooknum,
225 const struct net_device *in,
226 const struct net_device *out,
227 const void *targinfo,
228 void *userinfo)
229 {
230 if (net_ratelimit())
231 printk("arp_tables: error: '%s'\n", (char *)targinfo);
232
233 return NF_DROP;
234 }
235
236 static inline struct arpt_entry *get_entry(void *base, unsigned int offset)
237 {
238 return (struct arpt_entry *)(base + offset);
239 }
240
241 unsigned int arpt_do_table(struct sk_buff **pskb,
242 unsigned int hook,
243 const struct net_device *in,
244 const struct net_device *out,
245 struct arpt_table *table,
246 void *userdata)
247 {
248 static const char nulldevname[IFNAMSIZ] = { 0 };
249 unsigned int verdict = NF_DROP;
250 struct arphdr *arp = (*pskb)->nh.arph;
251 int hotdrop = 0;
252 struct arpt_entry *e, *back;
253 const char *indev, *outdev;
254 void *table_base;
255
256 indev = in ? in->name : nulldevname;
257 outdev = out ? out->name : nulldevname;
258
259 read_lock_bh(&table->lock);
260 table_base = (void *)table->private->entries
261 + TABLE_OFFSET(table->private,
262 cpu_number_map(smp_processor_id()));
263 e = get_entry(table_base, table->private->hook_entry[hook]);
264 back = get_entry(table_base, table->private->underflow[hook]);
265
266 do {
267 if (arp_packet_match(arp, (*pskb)->dev, indev, outdev, &e->arp)) {
268 struct arpt_entry_target *t;
269 int hdr_len;
270
271 hdr_len = sizeof(*arp) + (2 * sizeof(struct in_addr)) +
272 (2 * (*pskb)->dev->addr_len);
273 ADD_COUNTER(e->counters, hdr_len, 1);
274
275 t = arpt_get_target(e);
276
277 /* Standard target? */
278 if (!t->u.kernel.target->target) {
279 int v;
280
281 v = ((struct arpt_standard_target *)t)->verdict;
282 if (v < 0) {
283 /* Pop from stack? */
284 if (v != ARPT_RETURN) {
285 verdict = (unsigned)(-v) - 1;
286 break;
287 }
288 e = back;
289 back = get_entry(table_base,
290 back->comefrom);
291 continue;
292 }
293 if (table_base + v
294 != (void *)e + e->next_offset) {
295 /* Save old back ptr in next entry */
296 struct arpt_entry *next
297 = (void *)e + e->next_offset;
298 next->comefrom =
299 (void *)back - table_base;
300
301 /* set back pointer to next entry */
302 back = next;
303 }
304
305 e = get_entry(table_base, v);
306 } else {
307 /* Targets which reenter must return
308 * abs. verdicts
309 */
310 verdict = t->u.kernel.target->target(pskb,
311 hook,
312 in, out,
313 t->data,
314 userdata);
315
316 /* Target might have changed stuff. */
317 arp = (*pskb)->nh.arph;
318
319 if (verdict == ARPT_CONTINUE)
320 e = (void *)e + e->next_offset;
321 else
322 /* Verdict */
323 break;
324 }
325 } else {
326 e = (void *)e + e->next_offset;
327 }
328 } while (!hotdrop);
329 read_unlock_bh(&table->lock);
330
331 if (hotdrop)
332 return NF_DROP;
333 else
334 return verdict;
335 }
336
337 static inline void *find_inlist_lock_noload(struct list_head *head,
338 const char *name,
339 int *error,
340 struct semaphore *mutex)
341 {
342 void *ret;
343
344 *error = down_interruptible(mutex);
345 if (*error != 0)
346 return NULL;
347
348 ret = list_named_find(head, name);
349 if (!ret) {
350 *error = -ENOENT;
351 up(mutex);
352 }
353 return ret;
354 }
355
356 #ifndef CONFIG_KMOD
357 #define find_inlist_lock(h,n,p,e,m) find_inlist_lock_noload((h),(n),(e),(m))
358 #else
359 static void *
360 find_inlist_lock(struct list_head *head,
361 const char *name,
362 const char *prefix,
363 int *error,
364 struct semaphore *mutex)
365 {
366 void *ret;
367
368 ret = find_inlist_lock_noload(head, name, error, mutex);
369 if (!ret) {
370 char modulename[ARPT_FUNCTION_MAXNAMELEN + strlen(prefix) + 1];
371 strcpy(modulename, prefix);
372 strcat(modulename, name);
373 duprintf("find_inlist: loading `%s'.\n", modulename);
374 request_module(modulename);
375 ret = find_inlist_lock_noload(head, name, error, mutex);
376 }
377
378 return ret;
379 }
380 #endif
381
382 static inline struct arpt_table *find_table_lock(const char *name, int *error, struct semaphore *mutex)
383 {
384 return find_inlist_lock(&arpt_tables, name, "arptable_", error, mutex);
385 }
386
387 static inline struct arpt_target *find_target_lock(const char *name, int *error, struct semaphore *mutex)
388 {
389 return find_inlist_lock(&arpt_target, name, "arpt_", error, mutex);
390 }
391
392 /* All zeroes == unconditional rule. */
393 static inline int unconditional(const struct arpt_arp *arp)
394 {
395 unsigned int i;
396
397 for (i = 0; i < sizeof(*arp)/sizeof(__u32); i++)
398 if (((__u32 *)arp)[i])
399 return 0;
400
401 return 1;
402 }
403
404 /* Figures out from what hook each rule can be called: returns 0 if
405 * there are loops. Puts hook bitmask in comefrom.
406 */
407 static int mark_source_chains(struct arpt_table_info *newinfo, unsigned int valid_hooks)
408 {
409 unsigned int hook;
410
411 /* No recursion; use packet counter to save back ptrs (reset
412 * to 0 as we leave), and comefrom to save source hook bitmask.
413 */
414 for (hook = 0; hook < NF_ARP_NUMHOOKS; hook++) {
415 unsigned int pos = newinfo->hook_entry[hook];
416 struct arpt_entry *e
417 = (struct arpt_entry *)(newinfo->entries + pos);
418
419 if (!(valid_hooks & (1 << hook)))
420 continue;
421
422 /* Set initial back pointer. */
423 e->counters.pcnt = pos;
424
425 for (;;) {
426 struct arpt_standard_target *t
427 = (void *)arpt_get_target(e);
428
429 if (e->comefrom & (1 << NF_ARP_NUMHOOKS)) {
430 printk("arptables: loop hook %u pos %u %08X.\n",
431 hook, pos, e->comefrom);
432 return 0;
433 }
434 e->comefrom
435 |= ((1 << hook) | (1 << NF_ARP_NUMHOOKS));
436
437 /* Unconditional return/END. */
438 if (e->target_offset == sizeof(struct arpt_entry)
439 && (strcmp(t->target.u.user.name,
440 ARPT_STANDARD_TARGET) == 0)
441 && t->verdict < 0
442 && unconditional(&e->arp)) {
443 unsigned int oldpos, size;
444
445 /* Return: backtrack through the last
446 * big jump.
447 */
448 do {
449 e->comefrom ^= (1<<NF_ARP_NUMHOOKS);
450 oldpos = pos;
451 pos = e->counters.pcnt;
452 e->counters.pcnt = 0;
453
454 /* We're at the start. */
455 if (pos == oldpos)
456 goto next;
457
458 e = (struct arpt_entry *)
459 (newinfo->entries + pos);
460 } while (oldpos == pos + e->next_offset);
461
462 /* Move along one */
463 size = e->next_offset;
464 e = (struct arpt_entry *)
465 (newinfo->entries + pos + size);
466 e->counters.pcnt = pos;
467 pos += size;
468 } else {
469 int newpos = t->verdict;
470
471 if (strcmp(t->target.u.user.name,
472 ARPT_STANDARD_TARGET) == 0
473 && newpos >= 0) {
474 /* This a jump; chase it. */
475 duprintf("Jump rule %u -> %u\n",
476 pos, newpos);
477 } else {
478 /* ... this is a fallthru */
479 newpos = pos + e->next_offset;
480 }
481 e = (struct arpt_entry *)
482 (newinfo->entries + newpos);
483 e->counters.pcnt = pos;
484 pos = newpos;
485 }
486 }
487 next:
488 duprintf("Finished chain %u\n", hook);
489 }
490 return 1;
491 }
492
493 static inline int standard_check(const struct arpt_entry_target *t,
494 unsigned int max_offset)
495 {
496 struct arpt_standard_target *targ = (void *)t;
497
498 /* Check standard info. */
499 if (t->u.target_size
500 != ARPT_ALIGN(sizeof(struct arpt_standard_target))) {
501 duprintf("arpt_standard_check: target size %u != %Zu\n",
502 t->u.target_size,
503 ARPT_ALIGN(sizeof(struct arpt_standard_target)));
504 return 0;
505 }
506
507 if (targ->verdict >= 0
508 && targ->verdict > max_offset - sizeof(struct arpt_entry)) {
509 duprintf("arpt_standard_check: bad verdict (%i)\n",
510 targ->verdict);
511 return 0;
512 }
513
514 if (targ->verdict < -NF_MAX_VERDICT - 1) {
515 duprintf("arpt_standard_check: bad negative verdict (%i)\n",
516 targ->verdict);
517 return 0;
518 }
519 return 1;
520 }
521
522 static struct arpt_target arpt_standard_target;
523
524 static inline int check_entry(struct arpt_entry *e, const char *name, unsigned int size,
525 unsigned int *i)
526 {
527 struct arpt_entry_target *t;
528 struct arpt_target *target;
529 int ret;
530
531 if (!arp_checkentry(&e->arp)) {
532 duprintf("arp_tables: arp check failed %p %s.\n", e, name);
533 return -EINVAL;
534 }
535
536 t = arpt_get_target(e);
537 target = find_target_lock(t->u.user.name, &ret, &arpt_mutex);
538 if (!target) {
539 duprintf("check_entry: `%s' not found\n", t->u.user.name);
540 goto out;
541 }
542 if (target->me)
543 __MOD_INC_USE_COUNT(target->me);
544 t->u.kernel.target = target;
545 up(&arpt_mutex);
546
547 if (t->u.kernel.target == &arpt_standard_target) {
548 if (!standard_check(t, size)) {
549 ret = -EINVAL;
550 goto out;
551 }
552 } else if (t->u.kernel.target->checkentry
553 && !t->u.kernel.target->checkentry(name, e, t->data,
554 t->u.target_size
555 - sizeof(*t),
556 e->comefrom)) {
557 if (t->u.kernel.target->me)
558 __MOD_DEC_USE_COUNT(t->u.kernel.target->me);
559 duprintf("arp_tables: check failed for `%s'.\n",
560 t->u.kernel.target->name);
561 ret = -EINVAL;
562 goto out;
563 }
564
565 (*i)++;
566 return 0;
567
568 out:
569 return ret;
570 }
571
572 static inline int check_entry_size_and_hooks(struct arpt_entry *e,
573 struct arpt_table_info *newinfo,
574 unsigned char *base,
575 unsigned char *limit,
576 const unsigned int *hook_entries,
577 const unsigned int *underflows,
578 unsigned int *i)
579 {
580 unsigned int h;
581
582 if ((unsigned long)e % __alignof__(struct arpt_entry) != 0
583 || (unsigned char *)e + sizeof(struct arpt_entry) >= limit) {
584 duprintf("Bad offset %p\n", e);
585 return -EINVAL;
586 }
587
588 if (e->next_offset
589 < sizeof(struct arpt_entry) + sizeof(struct arpt_entry_target)) {
590 duprintf("checking: element %p size %u\n",
591 e, e->next_offset);
592 return -EINVAL;
593 }
594
595 /* Check hooks & underflows */
596 for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
597 if ((unsigned char *)e - base == hook_entries[h])
598 newinfo->hook_entry[h] = hook_entries[h];
599 if ((unsigned char *)e - base == underflows[h])
600 newinfo->underflow[h] = underflows[h];
601 }
602
603
604 /* Clear counters and comefrom */
605 e->counters = ((struct arpt_counters) { 0, 0 });
606 e->comefrom = 0;
607
608 (*i)++;
609 return 0;
610 }
611
612 static inline int cleanup_entry(struct arpt_entry *e, unsigned int *i)
613 {
614 struct arpt_entry_target *t;
615
616 if (i && (*i)-- == 0)
617 return 1;
618
619 t = arpt_get_target(e);
620 if (t->u.kernel.target->destroy)
621 t->u.kernel.target->destroy(t->data,
622 t->u.target_size - sizeof(*t));
623 if (t->u.kernel.target->me)
624 __MOD_DEC_USE_COUNT(t->u.kernel.target->me);
625
626 return 0;
627 }
628
629 /* Checks and translates the user-supplied table segment (held in
630 * newinfo).
631 */
632 static int translate_table(const char *name,
633 unsigned int valid_hooks,
634 struct arpt_table_info *newinfo,
635 unsigned int size,
636 unsigned int number,
637 const unsigned int *hook_entries,
638 const unsigned int *underflows)
639 {
640 unsigned int i;
641 int ret;
642
643 newinfo->size = size;
644 newinfo->number = number;
645
646 /* Init all hooks to impossible value. */
647 for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
648 newinfo->hook_entry[i] = 0xFFFFFFFF;
649 newinfo->underflow[i] = 0xFFFFFFFF;
650 }
651
652 duprintf("translate_table: size %u\n", newinfo->size);
653 i = 0;
654
655 /* Walk through entries, checking offsets. */
656 ret = ARPT_ENTRY_ITERATE(newinfo->entries, newinfo->size,
657 check_entry_size_and_hooks,
658 newinfo,
659 newinfo->entries,
660 newinfo->entries + size,
661 hook_entries, underflows, &i);
662 duprintf("translate_table: ARPT_ENTRY_ITERATE gives %d\n", ret);
663 if (ret != 0)
664 return ret;
665
666 if (i != number) {
667 duprintf("translate_table: %u not %u entries\n",
668 i, number);
669 return -EINVAL;
670 }
671
672 /* Check hooks all assigned */
673 for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
674 /* Only hooks which are valid */
675 if (!(valid_hooks & (1 << i)))
676 continue;
677 if (newinfo->hook_entry[i] == 0xFFFFFFFF) {
678 duprintf("Invalid hook entry %u %u\n",
679 i, hook_entries[i]);
680 return -EINVAL;
681 }
682 if (newinfo->underflow[i] == 0xFFFFFFFF) {
683 duprintf("Invalid underflow %u %u\n",
684 i, underflows[i]);
685 return -EINVAL;
686 }
687 }
688
689 if (!mark_source_chains(newinfo, valid_hooks)) {
690 duprintf("Looping hook\n");
691 return -ELOOP;
692 }
693
694 /* Finally, each sanity check must pass */
695 i = 0;
696 ret = ARPT_ENTRY_ITERATE(newinfo->entries, newinfo->size,
697 check_entry, name, size, &i);
698
699 if (ret != 0) {
700 ARPT_ENTRY_ITERATE(newinfo->entries, newinfo->size,
701 cleanup_entry, &i);
702 return ret;
703 }
704
705 /* And one copy for every other CPU */
706 for (i = 1; i < smp_num_cpus; i++) {
707 memcpy(newinfo->entries + SMP_ALIGN(newinfo->size)*i,
708 newinfo->entries,
709 SMP_ALIGN(newinfo->size));
710 }
711
712 return ret;
713 }
714
715 static struct arpt_table_info *replace_table(struct arpt_table *table,
716 unsigned int num_counters,
717 struct arpt_table_info *newinfo,
718 int *error)
719 {
720 struct arpt_table_info *oldinfo;
721
722 /* Do the substitution. */
723 write_lock_bh(&table->lock);
724 /* Check inside lock: is the old number correct? */
725 if (num_counters != table->private->number) {
726 duprintf("num_counters != table->private->number (%u/%u)\n",
727 num_counters, table->private->number);
728 write_unlock_bh(&table->lock);
729 *error = -EAGAIN;
730 return NULL;
731 }
732 oldinfo = table->private;
733 table->private = newinfo;
734 newinfo->initial_entries = oldinfo->initial_entries;
735 write_unlock_bh(&table->lock);
736
737 return oldinfo;
738 }
739
740 /* Gets counters. */
741 static inline int add_entry_to_counter(const struct arpt_entry *e,
742 struct arpt_counters total[],
743 unsigned int *i)
744 {
745 ADD_COUNTER(total[*i], e->counters.bcnt, e->counters.pcnt);
746
747 (*i)++;
748 return 0;
749 }
750
751 static void get_counters(const struct arpt_table_info *t,
752 struct arpt_counters counters[])
753 {
754 unsigned int cpu;
755 unsigned int i;
756
757 for (cpu = 0; cpu < smp_num_cpus; cpu++) {
758 i = 0;
759 ARPT_ENTRY_ITERATE(t->entries + TABLE_OFFSET(t, cpu),
760 t->size,
761 add_entry_to_counter,
762 counters,
763 &i);
764 }
765 }
766
767 static int copy_entries_to_user(unsigned int total_size,
768 struct arpt_table *table,
769 void *userptr)
770 {
771 unsigned int off, num, countersize;
772 struct arpt_entry *e;
773 struct arpt_counters *counters;
774 int ret = 0;
775
776 /* We need atomic snapshot of counters: rest doesn't change
777 * (other than comefrom, which userspace doesn't care
778 * about).
779 */
780 countersize = sizeof(struct arpt_counters) * table->private->number;
781 counters = vmalloc(countersize);
782
783 if (counters == NULL)
784 return -ENOMEM;
785
786 /* First, sum counters... */
787 memset(counters, 0, countersize);
788 write_lock_bh(&table->lock);
789 get_counters(table->private, counters);
790 write_unlock_bh(&table->lock);
791
792 /* ... then copy entire thing from CPU 0... */
793 if (copy_to_user(userptr, table->private->entries, total_size) != 0) {
794 ret = -EFAULT;
795 goto free_counters;
796 }
797
798 /* ... then go back and fix counters and names */
799 for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
800 struct arpt_entry_target *t;
801
802 e = (struct arpt_entry *)(table->private->entries + off);
803 if (copy_to_user(userptr + off
804 + offsetof(struct arpt_entry, counters),
805 &counters[num],
806 sizeof(counters[num])) != 0) {
807 ret = -EFAULT;
808 goto free_counters;
809 }
810
811 t = arpt_get_target(e);
812 if (copy_to_user(userptr + off + e->target_offset
813 + offsetof(struct arpt_entry_target,
814 u.user.name),
815 t->u.kernel.target->name,
816 strlen(t->u.kernel.target->name)+1) != 0) {
817 ret = -EFAULT;
818 goto free_counters;
819 }
820 }
821
822 free_counters:
823 vfree(counters);
824 return ret;
825 }
826
827 static int get_entries(const struct arpt_get_entries *entries,
828 struct arpt_get_entries *uptr)
829 {
830 int ret;
831 struct arpt_table *t;
832
833 t = find_table_lock(entries->name, &ret, &arpt_mutex);
834 if (t) {
835 duprintf("t->private->number = %u\n",
836 t->private->number);
837 if (entries->size == t->private->size)
838 ret = copy_entries_to_user(t->private->size,
839 t, uptr->entrytable);
840 else {
841 duprintf("get_entries: I've got %u not %u!\n",
842 t->private->size,
843 entries->size);
844 ret = -EINVAL;
845 }
846 up(&arpt_mutex);
847 } else
848 duprintf("get_entries: Can't find %s!\n",
849 entries->name);
850
851 return ret;
852 }
853
854 static int do_replace(void *user, unsigned int len)
855 {
856 int ret;
857 struct arpt_replace tmp;
858 struct arpt_table *t;
859 struct arpt_table_info *newinfo, *oldinfo;
860 struct arpt_counters *counters;
861
862 if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
863 return -EFAULT;
864
865 /* Hack: Causes ipchains to give correct error msg --RR */
866 if (len != sizeof(tmp) + tmp.size)
867 return -ENOPROTOOPT;
868
869 /* Pedantry: prevent them from hitting BUG() in vmalloc.c --RR */
870 if ((SMP_ALIGN(tmp.size) >> PAGE_SHIFT) + 2 > num_physpages)
871 return -ENOMEM;
872
873 newinfo = vmalloc(sizeof(struct arpt_table_info)
874 + SMP_ALIGN(tmp.size) * smp_num_cpus);
875 if (!newinfo)
876 return -ENOMEM;
877
878 if (copy_from_user(newinfo->entries, user + sizeof(tmp),
879 tmp.size) != 0) {
880 ret = -EFAULT;
881 goto free_newinfo;
882 }
883
884 counters = vmalloc(tmp.num_counters * sizeof(struct arpt_counters));
885 if (!counters) {
886 ret = -ENOMEM;
887 goto free_newinfo;
888 }
889 memset(counters, 0, tmp.num_counters * sizeof(struct arpt_counters));
890
891 ret = translate_table(tmp.name, tmp.valid_hooks,
892 newinfo, tmp.size, tmp.num_entries,
893 tmp.hook_entry, tmp.underflow);
894 if (ret != 0)
895 goto free_newinfo_counters;
896
897 duprintf("arp_tables: Translated table\n");
898
899 t = find_table_lock(tmp.name, &ret, &arpt_mutex);
900 if (!t)
901 goto free_newinfo_counters_untrans;
902
903 /* You lied! */
904 if (tmp.valid_hooks != t->valid_hooks) {
905 duprintf("Valid hook crap: %08X vs %08X\n",
906 tmp.valid_hooks, t->valid_hooks);
907 ret = -EINVAL;
908 goto free_newinfo_counters_untrans_unlock;
909 }
910
911 oldinfo = replace_table(t, tmp.num_counters, newinfo, &ret);
912 if (!oldinfo)
913 goto free_newinfo_counters_untrans_unlock;
914
915 /* Update module usage count based on number of rules */
916 duprintf("do_replace: oldnum=%u, initnum=%u, newnum=%u\n",
917 oldinfo->number, oldinfo->initial_entries, newinfo->number);
918 if (t->me && (oldinfo->number <= oldinfo->initial_entries) &&
919 (newinfo->number > oldinfo->initial_entries))
920 __MOD_INC_USE_COUNT(t->me);
921 else if (t->me && (oldinfo->number > oldinfo->initial_entries) &&
922 (newinfo->number <= oldinfo->initial_entries))
923 __MOD_DEC_USE_COUNT(t->me);
924
925 /* Get the old counters. */
926 get_counters(oldinfo, counters);
927 /* Decrease module usage counts and free resource */
928 ARPT_ENTRY_ITERATE(oldinfo->entries, oldinfo->size, cleanup_entry,NULL);
929 vfree(oldinfo);
930 /* Silent error: too late now. */
931 copy_to_user(tmp.counters, counters,
932 sizeof(struct arpt_counters) * tmp.num_counters);
933 vfree(counters);
934 up(&arpt_mutex);
935 return 0;
936
937 free_newinfo_counters_untrans_unlock:
938 up(&arpt_mutex);
939 free_newinfo_counters_untrans:
940 ARPT_ENTRY_ITERATE(newinfo->entries, newinfo->size, cleanup_entry, NULL);
941 free_newinfo_counters:
942 vfree(counters);
943 free_newinfo:
944 vfree(newinfo);
945 return ret;
946 }
947
948 /* We're lazy, and add to the first CPU; overflow works its fey magic
949 * and everything is OK.
950 */
951 static inline int add_counter_to_entry(struct arpt_entry *e,
952 const struct arpt_counters addme[],
953 unsigned int *i)
954 {
955
956 ADD_COUNTER(e->counters, addme[*i].bcnt, addme[*i].pcnt);
957
958 (*i)++;
959 return 0;
960 }
961
962 static int do_add_counters(void *user, unsigned int len)
963 {
964 unsigned int i;
965 struct arpt_counters_info tmp, *paddc;
966 struct arpt_table *t;
967 int ret;
968
969 if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
970 return -EFAULT;
971
972 if (len != sizeof(tmp) + tmp.num_counters*sizeof(struct arpt_counters))
973 return -EINVAL;
974
975 paddc = vmalloc(len);
976 if (!paddc)
977 return -ENOMEM;
978
979 if (copy_from_user(paddc, user, len) != 0) {
980 ret = -EFAULT;
981 goto free;
982 }
983
984 t = find_table_lock(tmp.name, &ret, &arpt_mutex);
985 if (!t)
986 goto free;
987
988 write_lock_bh(&t->lock);
989
990 #if 0 // removed 1.11 forward bug test
991 // 43011 (09?): checkme: modify by tanghui @ 2006-10-11 for a RACE CONDITION in the "do_add_counters()" function
992 // if (t->private->number != tmp.num_counters) {
993 #endif
994 if (t->private->number != paddc->num_counters) {
995 ret = -EINVAL;
996 goto unlock_up_free;
997 }
998
999 i = 0;
1000 ARPT_ENTRY_ITERATE(t->private->entries,
1001 t->private->size,
1002 add_counter_to_entry,
1003 paddc->counters,
1004 &i);
1005 unlock_up_free:
1006 write_unlock_bh(&t->lock);
1007 up(&arpt_mutex);
1008 free:
1009 vfree(paddc);
1010
1011 return ret;
1012 }
1013
1014 static int do_arpt_set_ctl(struct sock *sk, int cmd, void *user, unsigned int len)
1015 {
1016 int ret;
1017
1018 if (!capable(CAP_NET_ADMIN))
1019 return -EPERM;
1020
1021 switch (cmd) {
1022 case ARPT_SO_SET_REPLACE:
1023 ret = do_replace(user, len);
1024 break;
1025
1026 case ARPT_SO_SET_ADD_COUNTERS:
1027 ret = do_add_counters(user, len);
1028 break;
1029
1030 default:
1031 duprintf("do_arpt_set_ctl: unknown request %i\n", cmd);
1032 ret = -EINVAL;
1033 }
1034
1035 return ret;
1036 }
1037
1038 static int do_arpt_get_ctl(struct sock *sk, int cmd, void *user, int *len)
1039 {
1040 int ret;
1041
1042 if (!capable(CAP_NET_ADMIN))
1043 return -EPERM;
1044
1045 switch (cmd) {
1046 case ARPT_SO_GET_INFO: {
1047 char name[ARPT_TABLE_MAXNAMELEN];
1048 struct arpt_table *t;
1049
1050 if (*len != sizeof(struct arpt_getinfo)) {
1051 duprintf("length %u != %Zu\n", *len,
1052 sizeof(struct arpt_getinfo));
1053 ret = -EINVAL;
1054 break;
1055 }
1056
1057 if (copy_from_user(name, user, sizeof(name)) != 0) {
1058 ret = -EFAULT;
1059 break;
1060 }
1061 name[ARPT_TABLE_MAXNAMELEN-1] = '\0';
1062 t = find_table_lock(name, &ret, &arpt_mutex);
1063 if (t) {
1064 struct arpt_getinfo info;
1065
1066 info.valid_hooks = t->valid_hooks;
1067 memcpy(info.hook_entry, t->private->hook_entry,
1068 sizeof(info.hook_entry));
1069 memcpy(info.underflow, t->private->underflow,
1070 sizeof(info.underflow));
1071 info.num_entries = t->private->number;
1072 info.size = t->private->size;
1073 strcpy(info.name, name);
1074
1075 if (copy_to_user(user, &info, *len) != 0)
1076 ret = -EFAULT;
1077 else
1078 ret = 0;
1079
1080 up(&arpt_mutex);
1081 }
1082 }
1083 break;
1084
1085 case ARPT_SO_GET_ENTRIES: {
1086 struct arpt_get_entries get;
1087
1088 if (*len < sizeof(get)) {
1089 duprintf("get_entries: %u < %Zu\n", *len, sizeof(get));
1090 ret = -EINVAL;
1091 } else if (copy_from_user(&get, user, sizeof(get)) != 0) {
1092 ret = -EFAULT;
1093 } else if (*len != sizeof(struct arpt_get_entries) + get.size) {
1094 duprintf("get_entries: %u != %Zu\n", *len,
1095 sizeof(struct arpt_get_entries) + get.size);
1096 ret = -EINVAL;
1097 } else
1098 ret = get_entries(&get, user);
1099 break;
1100 }
1101
1102 default:
1103 duprintf("do_arpt_get_ctl: unknown request %i\n", cmd);
1104 ret = -EINVAL;
1105 }
1106
1107 return ret;
1108 }
1109
1110 /* Registration hooks for targets. */
1111 int arpt_register_target(struct arpt_target *target)
1112 {
1113 int ret;
1114
1115 MOD_INC_USE_COUNT;
1116 ret = down_interruptible(&arpt_mutex);
1117 if (ret != 0) {
1118 MOD_DEC_USE_COUNT;
1119 return ret;
1120 }
1121 if (!list_named_insert(&arpt_target, target)) {
1122 duprintf("arpt_register_target: `%s' already in list!\n",
1123 target->name);
1124 ret = -EINVAL;
1125 MOD_DEC_USE_COUNT;
1126 }
1127 up(&arpt_mutex);
1128 return ret;
1129 }
1130
1131 void arpt_unregister_target(struct arpt_target *target)
1132 {
1133 down(&arpt_mutex);
1134 LIST_DELETE(&arpt_target, target);
1135 up(&arpt_mutex);
1136 MOD_DEC_USE_COUNT;
1137 }
1138
1139 int arpt_register_table(struct arpt_table *table)
1140 {
1141 int ret;
1142 struct arpt_table_info *newinfo;
1143 static struct arpt_table_info bootstrap
1144 = { 0, 0, 0, { 0 }, { 0 }, { } };
1145
1146 MOD_INC_USE_COUNT;
1147 newinfo = vmalloc(sizeof(struct arpt_table_info)
1148 + SMP_ALIGN(table->table->size) * smp_num_cpus);
1149 if (!newinfo) {
1150 ret = -ENOMEM;
1151 MOD_DEC_USE_COUNT;
1152 return ret;
1153 }
1154 memcpy(newinfo->entries, table->table->entries, table->table->size);
1155
1156 ret = translate_table(table->name, table->valid_hooks,
1157 newinfo, table->table->size,
1158 table->table->num_entries,
1159 table->table->hook_entry,
1160 table->table->underflow);
1161 duprintf("arpt_register_table: translate table gives %d\n", ret);
1162 if (ret != 0) {
1163 vfree(newinfo);
1164 MOD_DEC_USE_COUNT;
1165 return ret;
1166 }
1167
1168 ret = down_interruptible(&arpt_mutex);
1169 if (ret != 0) {
1170 vfree(newinfo);
1171 MOD_DEC_USE_COUNT;
1172 return ret;
1173 }
1174
1175 /* Don't autoload: we'd eat our tail... */
1176 if (list_named_find(&arpt_tables, table->name)) {
1177 ret = -EEXIST;
1178 goto free_unlock;
1179 }
1180
1181 /* Simplifies replace_table code. */
1182 table->private = &bootstrap;
1183 if (!replace_table(table, 0, newinfo, &ret))
1184 goto free_unlock;
1185
1186 duprintf("table->private->number = %u\n",
1187 table->private->number);
1188
1189 /* save number of initial entries */
1190 table->private->initial_entries = table->private->number;
1191
1192 table->lock = RW_LOCK_UNLOCKED;
1193 list_prepend(&arpt_tables, table);
1194
1195 unlock:
1196 up(&arpt_mutex);
1197 return ret;
1198
1199 free_unlock:
1200 vfree(newinfo);
1201 MOD_DEC_USE_COUNT;
1202 goto unlock;
1203 }
1204
1205 void arpt_unregister_table(struct arpt_table *table)
1206 {
1207 down(&arpt_mutex);
1208 LIST_DELETE(&arpt_tables, table);
1209 up(&arpt_mutex);
1210
1211 /* Decrease module usage counts and free resources */
1212 ARPT_ENTRY_ITERATE(table->private->entries, table->private->size,
1213 cleanup_entry, NULL);
1214 vfree(table->private);
1215 MOD_DEC_USE_COUNT;
1216 }
1217
1218 /* The built-in targets: standard (NULL) and error. */
1219 static struct arpt_target arpt_standard_target
1220 = { { NULL, NULL }, ARPT_STANDARD_TARGET, NULL, NULL, NULL };
1221 static struct arpt_target arpt_error_target
1222 = { { NULL, NULL }, ARPT_ERROR_TARGET, arpt_error, NULL, NULL };
1223
1224 static struct nf_sockopt_ops arpt_sockopts
1225 = { { NULL, NULL }, PF_INET, ARPT_BASE_CTL, ARPT_SO_SET_MAX+1, do_arpt_set_ctl,
1226 ARPT_BASE_CTL, ARPT_SO_GET_MAX+1, do_arpt_get_ctl, 0, NULL };
1227
1228 #ifdef CONFIG_PROC_FS
1229 static inline int print_name(const struct arpt_table *t,
1230 off_t start_offset, char *buffer, int length,
1231 off_t *pos, unsigned int *count)
1232 {
1233 if ((*count)++ >= start_offset) {
1234 unsigned int namelen;
1235
1236 namelen = sprintf(buffer + *pos, "%s\n", t->name);
1237 if (*pos + namelen > length) {
1238 /* Stop iterating */
1239 return 1;
1240 }
1241 *pos += namelen;
1242 }
1243 return 0;
1244 }
1245
1246 static int arpt_get_tables(char *buffer, char **start, off_t offset, int length)
1247 {
1248 off_t pos = 0;
1249 unsigned int count = 0;
1250
1251 if (down_interruptible(&arpt_mutex) != 0)
1252 return 0;
1253
1254 LIST_FIND(&arpt_tables, print_name, struct arpt_table *,
1255 offset, buffer, length, &pos, &count);
1256
1257 up(&arpt_mutex);
1258
1259 /* `start' hack - see fs/proc/generic.c line ~105 */
1260 *start=(char *)((unsigned long)count-offset);
1261 return pos;
1262 }
1263 #endif /*CONFIG_PROC_FS*/
1264
1265 static int __init init(void)
1266 {
1267 int ret;
1268
1269 /* Noone else will be downing sem now, so we won't sleep */
1270 down(&arpt_mutex);
1271 list_append(&arpt_target, &arpt_standard_target);
1272 list_append(&arpt_target, &arpt_error_target);
1273 up(&arpt_mutex);
1274
1275 /* Register setsockopt */
1276 ret = nf_register_sockopt(&arpt_sockopts);
1277 if (ret < 0) {
1278 duprintf("Unable to register sockopts.\n");
1279 return ret;
1280 }
1281
1282 #ifdef CONFIG_PROC_FS
1283 {
1284 struct proc_dir_entry *proc;
1285
1286 proc = proc_net_create("arp_tables_names", 0, arpt_get_tables);
1287 if (!proc) {
1288 nf_unregister_sockopt(&arpt_sockopts);
1289 return -ENOMEM;
1290 }
1291 proc->owner = THIS_MODULE;
1292 }
1293 #endif
1294
1295 printk("arp_tables: (C) 2002 David S. Miller\n");
1296 return 0;
1297 }
1298
1299 static void __exit fini(void)
1300 {
1301 nf_unregister_sockopt(&arpt_sockopts);
1302 #ifdef CONFIG_PROC_FS
1303 proc_net_remove("arp_tables_names");
1304 #endif
1305 }
1306
1307 EXPORT_SYMBOL(arpt_register_table);
1308 EXPORT_SYMBOL(arpt_unregister_table);
1309 EXPORT_SYMBOL(arpt_do_table);
1310 EXPORT_SYMBOL(arpt_register_target);
1311 EXPORT_SYMBOL(arpt_unregister_target);
1312
1313 module_init(init);
1314 module_exit(fini);
1315 MODULE_LICENSE("GPL");
Tomato firmware and modifications.