File: communication.c

package info (click to toggle)
ebtables 2.0.11-4
  • links: PTS, VCS
  • area: main
  • in suites: bookworm, bullseye, sid
  • size: 2,144 kB
  • sloc: ansic: 9,451; sh: 4,647; makefile: 61; perl: 45
file content (772 lines) | stat: -rw-r--r-- 22,559 bytes parent folder | download | duplicates (3)
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
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
/*
 * communication.c, v2.0 July 2002
 *
 * Author: Bart De Schuymer
 *
 */

/*
 * All the userspace/kernel communication is in this file.
 * The other code should not have to know anything about the way the
 * kernel likes the structure of the table data.
 * The other code works with linked lists. So, the translation is done here.
 */

#include <getopt.h>
#include <string.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/socket.h>
#include "include/ebtables_u.h"

extern char* hooknames[NF_BR_NUMHOOKS];

#ifdef KERNEL_64_USERSPACE_32
#define sparc_cast (uint64_t)
#else
#define sparc_cast
#endif

int sockfd = -1;

static int get_sockfd()
{
	int ret = 0;
	if (sockfd == -1) {
		sockfd = socket(AF_INET, SOCK_RAW, PF_INET);
		if (sockfd < 0) {
			ebt_print_error("Problem getting a socket, "
					"you probably don't have the right "
					"permissions");
			ret = -1;
		}
	}
	return ret;
}

static struct ebt_replace *translate_user2kernel(struct ebt_u_replace *u_repl)
{
	struct ebt_replace *new;
	struct ebt_u_entry *e;
	struct ebt_u_match_list *m_l;
	struct ebt_u_watcher_list *w_l;
	struct ebt_u_entries *entries;
	char *p, *base;
	int i, j;
	unsigned int entries_size = 0, *chain_offsets;

	new = (struct ebt_replace *)malloc(sizeof(struct ebt_replace));
	if (!new)
		ebt_print_memory();
	new->valid_hooks = u_repl->valid_hooks;
	strcpy(new->name, u_repl->name);
	new->nentries = u_repl->nentries;
	new->num_counters = u_repl->num_counters;
	new->counters = sparc_cast u_repl->counters;
	chain_offsets = (unsigned int *)calloc(u_repl->num_chains, sizeof(unsigned int));
	if (!chain_offsets)
		ebt_print_memory();
	/* Determine size */
	for (i = 0; i < u_repl->num_chains; i++) {
		if (!(entries = u_repl->chains[i]))
			continue;
		chain_offsets[i] = entries_size;
		entries_size += sizeof(struct ebt_entries);
		j = 0;
		e = entries->entries->next;
		while (e != entries->entries) {
			j++;
			entries_size += sizeof(struct ebt_entry);
			m_l = e->m_list;
			while (m_l) {
				entries_size += m_l->m->match_size +
				   sizeof(struct ebt_entry_match);
				m_l = m_l->next;
			}
			w_l = e->w_list;
			while (w_l) {
				entries_size += w_l->w->watcher_size +
				   sizeof(struct ebt_entry_watcher);
				w_l = w_l->next;
			}
			entries_size += e->t->target_size +
			   sizeof(struct ebt_entry_target);
			e = e->next;
		}
		/* A little sanity check */
		if (j != entries->nentries)
			ebt_print_bug("Wrong nentries: %d != %d, hook = %s", j,
			   entries->nentries, entries->name);
	}

	new->entries_size = entries_size;
	p = (char *)malloc(entries_size);
	if (!p)
		ebt_print_memory();

	/* Put everything in one block */
	new->entries = sparc_cast p;
	for (i = 0; i < u_repl->num_chains; i++) {
		struct ebt_entries *hlp;

		hlp = (struct ebt_entries *)p;
		if (!(entries = u_repl->chains[i]))
			continue;
		if (i < NF_BR_NUMHOOKS)
			new->hook_entry[i] = sparc_cast hlp;
		hlp->nentries = entries->nentries;
		hlp->policy = entries->policy;
		strcpy(hlp->name, entries->name);
		hlp->counter_offset = entries->counter_offset;
		hlp->distinguisher = 0; /* Make the kernel see the light */
		p += sizeof(struct ebt_entries);
		e = entries->entries->next;
		while (e != entries->entries) {
			struct ebt_entry *tmp = (struct ebt_entry *)p;

			tmp->bitmask = e->bitmask | EBT_ENTRY_OR_ENTRIES;
			tmp->invflags = e->invflags;
			tmp->ethproto = e->ethproto;
			strcpy(tmp->in, e->in);
			strcpy(tmp->out, e->out);
			strcpy(tmp->logical_in, e->logical_in);
			strcpy(tmp->logical_out, e->logical_out);
			memcpy(tmp->sourcemac, e->sourcemac,
			   sizeof(tmp->sourcemac));
			memcpy(tmp->sourcemsk, e->sourcemsk,
			   sizeof(tmp->sourcemsk));
			memcpy(tmp->destmac, e->destmac, sizeof(tmp->destmac));
			memcpy(tmp->destmsk, e->destmsk, sizeof(tmp->destmsk));

			base = p;
			p += sizeof(struct ebt_entry);
			m_l = e->m_list;
			while (m_l) {
				memcpy(p, m_l->m, m_l->m->match_size +
				   sizeof(struct ebt_entry_match));
				p += m_l->m->match_size +
				   sizeof(struct ebt_entry_match);
				m_l = m_l->next;
			}
			tmp->watchers_offset = p - base;
			w_l = e->w_list;
			while (w_l) {
				memcpy(p, w_l->w, w_l->w->watcher_size +
				   sizeof(struct ebt_entry_watcher));
				p += w_l->w->watcher_size +
				   sizeof(struct ebt_entry_watcher);
				w_l = w_l->next;
			}
			tmp->target_offset = p - base;
			memcpy(p, e->t, e->t->target_size +
			   sizeof(struct ebt_entry_target));
			if (!strcmp(e->t->u.name, EBT_STANDARD_TARGET)) {
				struct ebt_standard_target *st =
				   (struct ebt_standard_target *)p;
				/* Translate the jump to a udc */
				if (st->verdict >= 0)
					st->verdict = chain_offsets
					   [st->verdict + NF_BR_NUMHOOKS];
			}
			p += e->t->target_size +
			   sizeof(struct ebt_entry_target);
			tmp->next_offset = p - base;
			e = e->next;
		}
	}

	/* Sanity check */
	if (p - (char *)new->entries != new->entries_size)
		ebt_print_bug("Entries_size bug");
	free(chain_offsets);
	return new;
}

static void store_table_in_file(char *filename, struct ebt_replace *repl)
{
	char *data;
	int size;
	int fd;

	/* Start from an empty file with the correct priviliges */
	if ((fd = creat(filename, 0600)) == -1) {
		ebt_print_error("Couldn't create file %s", filename);
		return;
	}

	size = sizeof(struct ebt_replace) + repl->entries_size +
	   repl->nentries * sizeof(struct ebt_counter);
	data = (char *)malloc(size);
	if (!data)
		ebt_print_memory();
	memcpy(data, repl, sizeof(struct ebt_replace));
	memcpy(data + sizeof(struct ebt_replace), (char *)repl->entries,
	   repl->entries_size);
	/* Initialize counters to zero, deliver_counters() can update them */
	memset(data + sizeof(struct ebt_replace) + repl->entries_size,
	   0, repl->nentries * sizeof(struct ebt_counter));
	if (write(fd, data, size) != size)
		ebt_print_error("Couldn't write everything to file %s",
				filename);
	close(fd);
	free(data);
}

void ebt_deliver_table(struct ebt_u_replace *u_repl)
{
	socklen_t optlen;
	struct ebt_replace *repl;

	/* Translate the struct ebt_u_replace to a struct ebt_replace */
	repl = translate_user2kernel(u_repl);
	if (u_repl->filename != NULL) {
		store_table_in_file(u_repl->filename, repl);
		goto free_repl;
	}
	/* Give the data to the kernel */
	optlen = sizeof(struct ebt_replace) + repl->entries_size;
	if (get_sockfd())
		goto free_repl;
	if (!setsockopt(sockfd, IPPROTO_IP, EBT_SO_SET_ENTRIES, repl, optlen))
		goto free_repl;
	if (u_repl->command == 8) { /* The ebtables module may not
	                             * yet be loaded with --atomic-commit */
		ebtables_insmod("ebtables");
		if (!setsockopt(sockfd, IPPROTO_IP, EBT_SO_SET_ENTRIES,
		    repl, optlen))
			goto free_repl;
	}

	ebt_print_error("Unable to update the kernel. Two possible causes:\n"
			"1. Multiple ebtables programs were executing simultaneously. The ebtables\n"
			"   userspace tool doesn't by default support multiple ebtables programs running\n"
			"   concurrently. The ebtables option --concurrent or a tool like flock can be\n"
			"   used to support concurrent scripts that update the ebtables kernel tables.\n"
			"2. The kernel doesn't support a certain ebtables extension, consider\n"
			"   recompiling your kernel or insmod the extension.\n");
free_repl:
	if (repl) {
		free(repl->entries);
		free(repl);
	}
}

static int store_counters_in_file(char *filename, struct ebt_u_replace *repl)
{
	int size = repl->nentries * sizeof(struct ebt_counter), ret = 0;
	unsigned int entries_size;
	struct ebt_replace hlp;
	FILE *file;

	if (!(file = fopen(filename, "r+b"))) {
		ebt_print_error("Could not open file %s", filename);
		return -1;
	}
	/* Find out entries_size and then set the file pointer to the
	 * counters */
	if (fseek(file, (char *)(&hlp.entries_size) - (char *)(&hlp), SEEK_SET)
	   || fread(&entries_size, sizeof(char), sizeof(unsigned int), file) !=
	   sizeof(unsigned int) ||
	   fseek(file, entries_size + sizeof(struct ebt_replace), SEEK_SET)) {
		ebt_print_error("File %s is corrupt", filename);
		ret = -1;
		goto close_file;
	}
	if (fwrite(repl->counters, sizeof(char), size, file) != size) {
		ebt_print_error("Could not write everything to file %s",
				filename);
		ret = -1;
	}
close_file:
	fclose(file);
	return ret;
}

/* Gets executed after ebt_deliver_table. Delivers the counters to the kernel
 * and resets the counterchanges to CNT_NORM */
void ebt_deliver_counters(struct ebt_u_replace *u_repl)
{
	struct ebt_counter *old, *new, *newcounters;
	socklen_t optlen;
	struct ebt_replace repl;
	struct ebt_cntchanges *cc = u_repl->cc->next, *cc2;
	struct ebt_u_entries *entries = NULL;
	struct ebt_u_entry *next = NULL;
	int i, chainnr = -1;

	if (u_repl->nentries == 0)
		return;

	newcounters = (struct ebt_counter *)
	   malloc(u_repl->nentries * sizeof(struct ebt_counter));
	if (!newcounters)
		ebt_print_memory();
	memset(newcounters, 0, u_repl->nentries * sizeof(struct ebt_counter));
	old = u_repl->counters;
	new = newcounters;
	while (cc != u_repl->cc) {
		if (!next || next == entries->entries) {
			chainnr++;
			while (chainnr < u_repl->num_chains && (!(entries = u_repl->chains[chainnr]) ||
			       (next = entries->entries->next) == entries->entries))
				chainnr++;
			if (chainnr == u_repl->num_chains)
				break;
		}
		if (next == NULL)
			ebt_print_bug("next == NULL");
		if (cc->type == CNT_NORM) {
			/* 'Normal' rule, meaning we didn't do anything to it
			 * So, we just copy */
			*new = *old;
			next->cnt = *new;
			next->cnt_surplus.pcnt = next->cnt_surplus.bcnt = 0;
			old++; /* We've used an old counter */
			new++; /* We've set a new counter */
			next = next->next;
		} else if (cc->type == CNT_DEL) {
			old++; /* Don't use this old counter */
		} else {
			if (cc->type == CNT_CHANGE) {
				if (cc->change % 3 == 1)
					new->pcnt = old->pcnt + next->cnt_surplus.pcnt;
				else if (cc->change % 3 == 2)
					new->pcnt = old->pcnt - next->cnt_surplus.pcnt;
				else
					new->pcnt = next->cnt.pcnt;
				if (cc->change / 3 == 1)
					new->bcnt = old->bcnt + next->cnt_surplus.bcnt;
				else if (cc->change / 3 == 2)
					new->bcnt = old->bcnt - next->cnt_surplus.bcnt;
				else
					new->bcnt = next->cnt.bcnt;
			} else
				*new = next->cnt;
			next->cnt = *new;
			next->cnt_surplus.pcnt = next->cnt_surplus.bcnt = 0;
			if (cc->type == CNT_ADD)
				new++;
			else {
				old++;
				new++;
			}
			next = next->next;
		}
		cc = cc->next;
	}

	free(u_repl->counters);
	u_repl->counters = newcounters;
	u_repl->num_counters = u_repl->nentries;
	/* Reset the counterchanges to CNT_NORM and delete the unused cc */
	i = 0;
	cc = u_repl->cc->next;
	while (cc != u_repl->cc) {
		if (cc->type == CNT_DEL) {
			cc->prev->next = cc->next;
			cc->next->prev = cc->prev;
			cc2 = cc->next;
			free(cc);
			cc = cc2;
		} else {
			cc->type = CNT_NORM;
			cc->change = 0;
			i++;
			cc = cc->next;
		}
	}
	if (i != u_repl->nentries)
		ebt_print_bug("i != u_repl->nentries");
	if (u_repl->filename != NULL) {
		store_counters_in_file(u_repl->filename, u_repl);
		return;
	}
	optlen = u_repl->nentries * sizeof(struct ebt_counter) +
	   sizeof(struct ebt_replace);
	/* Now put the stuff in the kernel's struct ebt_replace */
	repl.counters = sparc_cast u_repl->counters;
	repl.num_counters = u_repl->num_counters;
	memcpy(repl.name, u_repl->name, sizeof(repl.name));

	if (get_sockfd())
		return;
	if (setsockopt(sockfd, IPPROTO_IP, EBT_SO_SET_COUNTERS, &repl, optlen))
		ebt_print_bug("Couldn't update kernel counters");
}

static int
ebt_translate_match(struct ebt_entry_match *m, struct ebt_u_match_list ***l)
{
	struct ebt_u_match_list *new;
	int ret = 0;

	new = (struct ebt_u_match_list *)
	   malloc(sizeof(struct ebt_u_match_list));
	if (!new)
		ebt_print_memory();
	new->m = (struct ebt_entry_match *)
	   malloc(m->match_size + sizeof(struct ebt_entry_match));
	if (!new->m)
		ebt_print_memory();
	memcpy(new->m, m, m->match_size + sizeof(struct ebt_entry_match));
	new->next = NULL;
	**l = new;
	*l = &new->next;
	if (ebt_find_match(new->m->u.name) == NULL) {
		ebt_print_error("Kernel match %s unsupported by userspace tool",
				new->m->u.name);
		ret = -1;
	}
	return ret;
}

static int
ebt_translate_watcher(struct ebt_entry_watcher *w,
   struct ebt_u_watcher_list ***l)
{
	struct ebt_u_watcher_list *new;
	int ret = 0;

	new = (struct ebt_u_watcher_list *)
	   malloc(sizeof(struct ebt_u_watcher_list));
	if (!new)
		ebt_print_memory();
	new->w = (struct ebt_entry_watcher *)
	   malloc(w->watcher_size + sizeof(struct ebt_entry_watcher));
	if (!new->w)
		ebt_print_memory();
	memcpy(new->w, w, w->watcher_size + sizeof(struct ebt_entry_watcher));
	new->next = NULL;
	**l = new;
	*l = &new->next;
	if (ebt_find_watcher(new->w->u.name) == NULL) {
		ebt_print_error("Kernel watcher %s unsupported by userspace "
				"tool", new->w->u.name);
		ret = -1;
	}
	return ret;
}

static int
ebt_translate_entry(struct ebt_entry *e, int *hook, int *n, int *cnt,
   int *totalcnt, struct ebt_u_entry **u_e, struct ebt_u_replace *u_repl,
   unsigned int valid_hooks, char *base, struct ebt_cntchanges **cc)
{
	/* An entry */
	if (e->bitmask & EBT_ENTRY_OR_ENTRIES) {
		struct ebt_u_entry *new;
		struct ebt_u_match_list **m_l;
		struct ebt_u_watcher_list **w_l;
		struct ebt_entry_target *t;

		new = (struct ebt_u_entry *)malloc(sizeof(struct ebt_u_entry));
		if (!new)
			ebt_print_memory();
		new->bitmask = e->bitmask;
		/*
		 * Plain userspace code doesn't know about
		 * EBT_ENTRY_OR_ENTRIES
		 */
		new->bitmask &= ~EBT_ENTRY_OR_ENTRIES;
		new->invflags = e->invflags;
		new->ethproto = e->ethproto;
		strcpy(new->in, e->in);
		strcpy(new->out, e->out);
		strcpy(new->logical_in, e->logical_in);
		strcpy(new->logical_out, e->logical_out);
		memcpy(new->sourcemac, e->sourcemac, sizeof(new->sourcemac));
		memcpy(new->sourcemsk, e->sourcemsk, sizeof(new->sourcemsk));
		memcpy(new->destmac, e->destmac, sizeof(new->destmac));
		memcpy(new->destmsk, e->destmsk, sizeof(new->destmsk));
		if (*totalcnt >= u_repl->nentries)
			ebt_print_bug("*totalcnt >= u_repl->nentries");
		new->cnt = u_repl->counters[*totalcnt];
		new->cnt_surplus.pcnt = new->cnt_surplus.bcnt = 0;
		new->cc = *cc;
		*cc = (*cc)->next;
		new->m_list = NULL;
		new->w_list = NULL;
		new->next = (*u_e)->next;
		new->next->prev = new;
		(*u_e)->next = new;
		new->prev = *u_e;
		*u_e = new;
		m_l = &new->m_list;
		EBT_MATCH_ITERATE(e, ebt_translate_match, &m_l);
		w_l = &new->w_list;
		EBT_WATCHER_ITERATE(e, ebt_translate_watcher, &w_l);

		t = (struct ebt_entry_target *)(((char *)e) + e->target_offset);
		new->t = (struct ebt_entry_target *)
		   malloc(t->target_size + sizeof(struct ebt_entry_target));
		if (!new->t)
			ebt_print_memory();
		if (ebt_find_target(t->u.name) == NULL) {
			ebt_print_error("Kernel target %s unsupported by "
					"userspace tool", t->u.name);
			return -1;
		}
		memcpy(new->t, t, t->target_size +
		   sizeof(struct ebt_entry_target));
		/* Deal with jumps to udc */
		if (!strcmp(t->u.name, EBT_STANDARD_TARGET)) {
			char *tmp = base;
			int verdict = ((struct ebt_standard_target *)t)->verdict;
			int i;

			if (verdict >= 0) {
				tmp += verdict;
				for (i = NF_BR_NUMHOOKS; i < u_repl->num_chains; i++)
					if (u_repl->chains[i]->kernel_start == tmp)
						break;
				if (i == u_repl->num_chains)
					ebt_print_bug("Can't find udc for jump");
				((struct ebt_standard_target *)new->t)->verdict = i-NF_BR_NUMHOOKS;
			}
		}

		(*cnt)++;
		(*totalcnt)++;
		return 0;
	} else { /* A new chain */
		int i;
		struct ebt_entries *entries = (struct ebt_entries *)e;

		if (*n != *cnt)
			ebt_print_bug("Nr of entries in the chain is wrong");
		*n = entries->nentries;
		*cnt = 0;
		for (i = *hook + 1; i < NF_BR_NUMHOOKS; i++)
			if (valid_hooks & (1 << i))
				break;
		*hook = i;
		*u_e = u_repl->chains[*hook]->entries;
		return 0;
	}
}

/* Initialize all chain headers */
static int
ebt_translate_chains(struct ebt_entry *e, int *hook,
   struct ebt_u_replace *u_repl, unsigned int valid_hooks)
{
	int i;
	struct ebt_entries *entries = (struct ebt_entries *)e;
	struct ebt_u_entries *new;

	if (!(e->bitmask & EBT_ENTRY_OR_ENTRIES)) {
		for (i = *hook + 1; i < NF_BR_NUMHOOKS; i++)
			if (valid_hooks & (1 << i))
				break;
		new = (struct ebt_u_entries *)malloc(sizeof(struct ebt_u_entries));
		if (!new)
			ebt_print_memory();
		if (i == u_repl->max_chains)
			ebt_double_chains(u_repl);
		u_repl->chains[i] = new;
		if (i >= NF_BR_NUMHOOKS)
			new->kernel_start = (char *)e;
		*hook = i;
		new->nentries = entries->nentries;
		new->policy = entries->policy;
		new->entries = (struct ebt_u_entry *)malloc(sizeof(struct ebt_u_entry));
		if (!new->entries)
			ebt_print_memory();
		new->entries->next = new->entries->prev = new->entries;
		new->counter_offset = entries->counter_offset;
		strcpy(new->name, entries->name);
	}
	return 0;
}

static int retrieve_from_file(char *filename, struct ebt_replace *repl,
   char command)
{
	FILE *file;
	char *hlp = NULL, *entries;
	struct ebt_counter *counters;
	int size, ret = 0;

	if (!(file = fopen(filename, "r+b"))) {
		ebt_print_error("Could not open file %s", filename);
		return -1;
	}
	/* Make sure table name is right if command isn't -L or --atomic-commit */
	if (command != 'L' && command != 8) {
		hlp = (char *)malloc(strlen(repl->name) + 1);
		if (!hlp)
			ebt_print_memory();
		strcpy(hlp, repl->name);
	}
	if (fread(repl, sizeof(char), sizeof(struct ebt_replace), file)
	   != sizeof(struct ebt_replace)) {
		ebt_print_error("File %s is corrupt", filename);
		ret = -1;
		goto close_file;
	}
	if (command != 'L' && command != 8 && strcmp(hlp, repl->name)) {
		ebt_print_error("File %s contains wrong table name or is "
				"corrupt", filename);
		ret = -1;
		goto close_file;
	} else if (!ebt_find_table(repl->name)) {
		ebt_print_error("File %s contains invalid table name",
				filename);
		ret = -1;
		goto close_file;
	}

	size = sizeof(struct ebt_replace) +
	   repl->nentries * sizeof(struct ebt_counter) + repl->entries_size;
	fseek(file, 0, SEEK_END);
	if (size != ftell(file)) {
		ebt_print_error("File %s has wrong size", filename);
		ret = -1;
		goto close_file;
	}
	entries = (char *)malloc(repl->entries_size);
	if (!entries)
		ebt_print_memory();
	repl->entries = sparc_cast entries;
	if (repl->nentries) {
		counters = (struct ebt_counter *)
		   malloc(repl->nentries * sizeof(struct ebt_counter));
		repl->counters = sparc_cast counters;
		if (!repl->counters)
			ebt_print_memory();
	} else
		repl->counters = sparc_cast NULL;
	/* Copy entries and counters */
	if (fseek(file, sizeof(struct ebt_replace), SEEK_SET) ||
	   fread((char *)repl->entries, sizeof(char), repl->entries_size, file)
	   != repl->entries_size ||
	   fseek(file, sizeof(struct ebt_replace) + repl->entries_size,
		 SEEK_SET)
	   || (repl->counters && fread((char *)repl->counters, sizeof(char),
	   repl->nentries * sizeof(struct ebt_counter), file)
	   != repl->nentries * sizeof(struct ebt_counter))) {
		ebt_print_error("File %s is corrupt", filename);
		free(entries);
		repl->entries = NULL;
		ret = -1;
	}
close_file:
	fclose(file);
	free(hlp);
	return ret;
}

static int retrieve_from_kernel(struct ebt_replace *repl, char command,
				int init)
{
	socklen_t optlen;
	int optname;
	char *entries;

	optlen = sizeof(struct ebt_replace);
	if (get_sockfd())
		return -1;
	/* --atomic-init || --init-table */
	if (init)
		optname = EBT_SO_GET_INIT_INFO;
	else
		optname = EBT_SO_GET_INFO;
	if (getsockopt(sockfd, IPPROTO_IP, optname, repl, &optlen))
		return -1;

	if ( !(entries = (char *)malloc(repl->entries_size)) )
		ebt_print_memory();
	repl->entries = sparc_cast entries;
	if (repl->nentries) {
		struct ebt_counter *counters;

		if (!(counters = (struct ebt_counter *)
		   malloc(repl->nentries * sizeof(struct ebt_counter))) )
			ebt_print_memory();
		repl->counters = sparc_cast counters;
	}
	else
		repl->counters = sparc_cast NULL;

	/* We want to receive the counters */
	repl->num_counters = repl->nentries;
	optlen += repl->entries_size + repl->num_counters *
	   sizeof(struct ebt_counter);
	if (init)
		optname = EBT_SO_GET_INIT_ENTRIES;
	else
		optname = EBT_SO_GET_ENTRIES;
	if (getsockopt(sockfd, IPPROTO_IP, optname, repl, &optlen))
		ebt_print_bug("Hmm, what is wrong??? bug#1");

	return 0;
}

int ebt_get_table(struct ebt_u_replace *u_repl, int init)
{
	int i, j, k, hook;
	struct ebt_replace repl;
	struct ebt_u_entry *u_e = NULL;
	struct ebt_cntchanges *new_cc = NULL, *cc;

	strcpy(repl.name, u_repl->name);
	if (u_repl->filename != NULL) {
		if (init)
			ebt_print_bug("Getting initial table data from a file is impossible");
		if (retrieve_from_file(u_repl->filename, &repl, u_repl->command))
			return -1;
		/* -L with a wrong table name should be dealt with silently */
		strcpy(u_repl->name, repl.name);
	} else if (retrieve_from_kernel(&repl, u_repl->command, init))
		return -1;

	/* Translate the struct ebt_replace to a struct ebt_u_replace */
	u_repl->valid_hooks = repl.valid_hooks;
	u_repl->nentries = repl.nentries;
	u_repl->num_counters = repl.num_counters;
	u_repl->counters = repl.counters;
	u_repl->cc = (struct ebt_cntchanges *)malloc(sizeof(struct ebt_cntchanges));
	if (!u_repl->cc)
		ebt_print_memory();
	u_repl->cc->next = u_repl->cc->prev = u_repl->cc;
	cc = u_repl->cc;
	for (i = 0; i < repl.nentries; i++) {
		new_cc = (struct ebt_cntchanges *)malloc(sizeof(struct ebt_cntchanges));
		if (!new_cc)
			ebt_print_memory();
		new_cc->type = CNT_NORM;
		new_cc->change = 0;
		new_cc->prev = cc;
		cc->next = new_cc;
		cc = new_cc;
	}
	if (repl.nentries) {
		new_cc->next = u_repl->cc;
		u_repl->cc->prev = new_cc;
	}
	u_repl->chains = (struct ebt_u_entries **)calloc(EBT_ORI_MAX_CHAINS, sizeof(void *));
	u_repl->max_chains = EBT_ORI_MAX_CHAINS;
	hook = -1;
	/* FIXME: Clean up when an error is encountered */
	EBT_ENTRY_ITERATE(repl.entries, repl.entries_size, ebt_translate_chains,
	   &hook, u_repl, u_repl->valid_hooks);
	if (hook >= NF_BR_NUMHOOKS)
		u_repl->num_chains = hook + 1;
	else
		u_repl->num_chains = NF_BR_NUMHOOKS;
	i = 0; /* Holds the expected nr. of entries for the chain */
	j = 0; /* Holds the up to now counted entries for the chain */
	k = 0; /* Holds the total nr. of entries, should equal u_repl->nentries afterwards */
	cc = u_repl->cc->next;
	hook = -1;
	EBT_ENTRY_ITERATE((char *)repl.entries, repl.entries_size,
	   ebt_translate_entry, &hook, &i, &j, &k, &u_e, u_repl,
	   u_repl->valid_hooks, (char *)repl.entries, &cc);
	if (k != u_repl->nentries)
		ebt_print_bug("Wrong total nentries");
	free(repl.entries);
	return 0;
}