summaryrefslogtreecommitdiffstats
path: root/userspace/ebtables2/useful_functions.c
blob: d14cbe9dbdba14d5ec3433d0f6ef13320f8bb62c (plain)
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
/*
 * useful_functions.c, January 2004
 *
 * Random collection of functions that can be used by extensions.
 *
 * Author: Bart De Schuymer
 *
 *  This code is stongly inspired on the iptables code which is
 *  Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
#include "include/ebtables_u.h"
#include "include/ethernetdb.h"
#include <stdio.h>
#include <netinet/ether.h>
#include <string.h>
#include <stdlib.h>
#include <getopt.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>

const unsigned char mac_type_unicast[ETH_ALEN] =   {0,0,0,0,0,0};
const unsigned char msk_type_unicast[ETH_ALEN] =   {1,0,0,0,0,0};
const unsigned char mac_type_multicast[ETH_ALEN] = {1,0,0,0,0,0};
const unsigned char msk_type_multicast[ETH_ALEN] = {1,0,0,0,0,0};
const unsigned char mac_type_broadcast[ETH_ALEN] = {255,255,255,255,255,255};
const unsigned char msk_type_broadcast[ETH_ALEN] = {255,255,255,255,255,255};
const unsigned char mac_type_bridge_group[ETH_ALEN] = {0x01,0x80,0xc2,0,0,0};
const unsigned char msk_type_bridge_group[ETH_ALEN] = {255,255,255,255,255,255};

/* 0: default, print only 2 digits if necessary
 * 2: always print 2 digits, a printed mac address
 * then always has the same length */
int ebt_printstyle_mac;

void ebt_print_mac(const unsigned char *mac)
{
	if (ebt_printstyle_mac == 2) {
		int j;
		for (j = 0; j < ETH_ALEN; j++)
			printf("%02x%s", mac[j],
				(j==ETH_ALEN-1) ? "" : ":");
	} else
		printf("%s", ether_ntoa((struct ether_addr *) mac));
}

void ebt_print_mac_and_mask(const unsigned char *mac, const unsigned char *mask)
{
	char hlpmsk[6] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};

	if (!memcmp(mac, mac_type_unicast, 6) &&
	    !memcmp(mask, msk_type_unicast, 6))
		printf("Unicast");
	else if (!memcmp(mac, mac_type_multicast, 6) &&
	         !memcmp(mask, msk_type_multicast, 6))
		printf("Multicast");
	else if (!memcmp(mac, mac_type_broadcast, 6) &&
	         !memcmp(mask, msk_type_broadcast, 6))
		printf("Broadcast");
	else if (!memcmp(mac, mac_type_bridge_group, 6) &&
	         !memcmp(mask, msk_type_bridge_group, 6))
		printf("BGA");
	else {
		ebt_print_mac(mac);
		if (memcmp(mask, hlpmsk, 6)) {
			printf("/");
			ebt_print_mac(mask);
		}
	}
}

/* Checks the type for validity and calls getethertypebynumber(). */
struct ethertypeent *parseethertypebynumber(int type)
{
	if (type < 1536)
		ebt_print_error("Ethernet protocols have values >= 0x0600");
	if (type > 0xffff)
		ebt_print_error("Ethernet protocols have values <= 0xffff");
	return getethertypebynumber(type);
}

/* Put the mac address into 6 (ETH_ALEN) bytes returns 0 on success. */
int ebt_get_mac_and_mask(const char *from, unsigned char *to,
  unsigned char *mask)
{
	char *p;
	int i;
	struct ether_addr *addr;

	if (strcasecmp(from, "Unicast") == 0) {
		memcpy(to, mac_type_unicast, ETH_ALEN);
		memcpy(mask, msk_type_unicast, ETH_ALEN);
		return 0;
	}
	if (strcasecmp(from, "Multicast") == 0) {
		memcpy(to, mac_type_multicast, ETH_ALEN);
		memcpy(mask, msk_type_multicast, ETH_ALEN);
		return 0;
	}
	if (strcasecmp(from, "Broadcast") == 0) {
		memcpy(to, mac_type_broadcast, ETH_ALEN);
		memcpy(mask, msk_type_broadcast, ETH_ALEN);
		return 0;
	}
	if (strcasecmp(from, "BGA") == 0) {
		memcpy(to, mac_type_bridge_group, ETH_ALEN);
		memcpy(mask, msk_type_bridge_group, ETH_ALEN);
		return 0;
	}
	if ( (p = strrchr(from, '/')) != NULL) {
		*p = '\0';
		if (!(addr = ether_aton(p + 1)))
			return -1;
		memcpy(mask, addr, ETH_ALEN);
	} else
		memset(mask, 0xff, ETH_ALEN);
	if (!(addr = ether_aton(from)))
		return -1;
	memcpy(to, addr, ETH_ALEN);
	for (i = 0; i < ETH_ALEN; i++)
		to[i] &= mask[i];
	return 0;
}

/* 0: default
 * 1: the inverse '!' of the option has already been specified */
int ebt_invert = 0;

/*
 * Check if the inverse of the option is specified. This is used
 * in the parse functions of the extensions and ebtables.c
 */
int _ebt_check_inverse(const char option[], int argc, char **argv)
{
	if (!option)
		return ebt_invert;
	if (strcmp(option, "!") == 0) {
		if (ebt_invert == 1)
			ebt_print_error("Double use of '!' not allowed");
		if (optind >= argc)
			optarg = NULL;
		else
			optarg = argv[optind];
		optind++;
		ebt_invert = 1;
		return 1;
	}
	return ebt_invert;
}

/* Make sure the same option wasn't specified twice. This is used
 * in the parse functions of the extensions and ebtables.c */
void ebt_check_option(unsigned int *flags, unsigned int mask)
{
	if (*flags & mask)
		ebt_print_error("Multiple use of same option not allowed");
	*flags |= mask;
}

/* Put the ip string into 4 bytes. */
static int undot_ip(char *ip, unsigned char *ip2)
{
	char *p, *q, *end;
	long int onebyte;
	int i;
	char buf[20];

	strncpy(buf, ip, sizeof(buf) - 1);

	p = buf;
	for (i = 0; i < 3; i++) {
		if ((q = strchr(p, '.')) == NULL)
			return -1;
		*q = '\0';
		onebyte = strtol(p, &end, 10);
		if (*end != '\0' || onebyte > 255 || onebyte < 0)   
			return -1;
		ip2[i] = (unsigned char)onebyte;
		p = q + 1;
	}

	onebyte = strtol(p, &end, 10);
	if (*end != '\0' || onebyte > 255 || onebyte < 0)
		return -1;
	ip2[3] = (unsigned char)onebyte;

	return 0;
}

/* Put the mask into 4 bytes. */
static int ip_mask(char *mask, unsigned char *mask2)
{
	char *end;
	long int bits;
	uint32_t mask22;

	if (undot_ip(mask, mask2)) {
		/* not the /a.b.c.e format, maybe the /x format */
		bits = strtol(mask, &end, 10);
		if (*end != '\0' || bits > 32 || bits < 0)
			return -1;
		if (bits != 0) {
			mask22 = htonl(0xFFFFFFFF << (32 - bits));
			memcpy(mask2, &mask22, 4);
		} else {
			mask22 = 0xFFFFFFFF;
			memcpy(mask2, &mask22, 4);
		}
	}
	return 0;
}

/* Set the ip mask and ip address. Callers should check ebt_errormsg[0].
 * The string pointed to by address can be altered. */
void ebt_parse_ip_address(char *address, uint32_t *addr, uint32_t *msk)
{
	char *p;

	/* first the mask */
	if ((p = strrchr(address, '/')) != NULL) {
		*p = '\0';
		if (ip_mask(p + 1, (unsigned char *)msk)) {
			ebt_print_error("Problem with the IP mask '%s'", p + 1);
			return;
		}
	} else
		*msk = 0xFFFFFFFF;

	if (undot_ip(address, (unsigned char *)addr)) {
		ebt_print_error("Problem with the IP address '%s'", address);
		return;
	}
	*addr = *addr & *msk;
}


/* Transform the ip mask into a string ready for output. */
char *ebt_mask_to_dotted(uint32_t mask)
{
	int i;
	static char buf[20];
	uint32_t maskaddr, bits;

	maskaddr = ntohl(mask);

	/* don't print /32 */
	if (mask == 0xFFFFFFFFL) {
		*buf = '\0';
		return buf;
	}

	i = 32;
	bits = 0xFFFFFFFEL; /* Case 0xFFFFFFFF has just been dealt with */
	while (--i >= 0 && maskaddr != bits)
		bits <<= 1;

	if (i > 0)
		sprintf(buf, "/%d", i);
	else if (!i)
		*buf = '\0';
	else
		/* Mask was not a decent combination of 1's and 0's */
		sprintf(buf, "/%d.%d.%d.%d", ((unsigned char *)&mask)[0], 
		   ((unsigned char *)&mask)[1], ((unsigned char *)&mask)[2],
		   ((unsigned char *)&mask)[3]);

	return buf;
}

/* Most of the following code is derived from iptables */
static void
in6addrcpy(struct in6_addr *dst, struct in6_addr *src)
{
	memcpy(dst, src, sizeof(struct in6_addr));
}

int string_to_number_ll(const char *s, unsigned long long min,
            unsigned long long max, unsigned long long *ret)
{
	unsigned long long number;
	char *end;

	/* Handle hex, octal, etc. */
	errno = 0;
	number = strtoull(s, &end, 0);
	if (*end == '\0' && end != s) {
		/* we parsed a number, let's see if we want this */
		if (errno != ERANGE && min <= number && (!max || number <= max)) {
			*ret = number;
			return 0;
		}
	}
	return -1;
}

int string_to_number_l(const char *s, unsigned long min, unsigned long max,
                       unsigned long *ret)
{
	int result;
	unsigned long long number;

	result = string_to_number_ll(s, min, max, &number);
	*ret = (unsigned long)number;

	return result;
}

int string_to_number(const char *s, unsigned int min, unsigned int max,
                     unsigned int *ret)
{
	int result;
	unsigned long number;

	result = string_to_number_l(s, min, max, &number);
	*ret = (unsigned int)number;

	return result;
}

static struct in6_addr *numeric_to_addr(const char *num)
{
	static struct in6_addr ap;
	int err;

	if ((err=inet_pton(AF_INET6, num, &ap)) == 1)
		return &ap;
	return (struct in6_addr *)NULL;
}

static struct in6_addr *parse_ip6_mask(char *mask)
{
	static struct in6_addr maskaddr;
	struct in6_addr *addrp;
	unsigned int bits;

	if (mask == NULL) {
		/* no mask at all defaults to 128 bits */
		memset(&maskaddr, 0xff, sizeof maskaddr);
		return &maskaddr;
	}
	if ((addrp = numeric_to_addr(mask)) != NULL)
		return addrp;
	if (string_to_number(mask, 0, 128, &bits) == -1)
		ebt_print_error("Invalid IPv6 Mask '%s' specified", mask);
	if (bits != 0) {
		char *p = (char *)&maskaddr;
		memset(p, 0xff, bits / 8);
		memset(p + (bits / 8) + 1, 0, (128 - bits) / 8);
		p[bits / 8] = 0xff << (8 - (bits & 7));
		return &maskaddr;
	}

	memset(&maskaddr, 0, sizeof maskaddr);
	return &maskaddr;
}

/* Set the ipv6 mask and address. Callers should check ebt_errormsg[0].
 * The string pointed to by address can be altered. */
void ebt_parse_ip6_address(char *address, struct in6_addr *addr,
                           struct in6_addr *msk)
{
	struct in6_addr *tmp_addr;
	char buf[256];
	char *p;
	int i;
	int err;

	strncpy(buf, address, sizeof(buf) - 1);
	/* first the mask */
	buf[sizeof(buf) - 1] = '\0';
	if ((p = strrchr(buf, '/')) != NULL) {
		*p = '\0';
		tmp_addr = parse_ip6_mask(p + 1);
	} else
		tmp_addr = parse_ip6_mask(NULL);
	in6addrcpy(msk, tmp_addr);

	/* if a null mask is given, the name is ignored, like in "any/0" */
	if (!memcmp(msk, &in6addr_any, sizeof(in6addr_any)))
		strcpy(buf, "::");

	if ((err=inet_pton(AF_INET6, buf, addr)) < 1) {
		ebt_print_error("Invalid IPv6 Address '%s' specified", buf);
		return;
	}

	for (i = 0; i < 4; i++)
		addr->s6_addr32[i] &= msk->s6_addr32[i];
}

/* Transform the ip6 addr into a string ready for output. */
char *ebt_ip6_to_numeric(const struct in6_addr *addrp)
{
	/* 0000:0000:0000:0000:0000:000.000.000.000
	 * 0000:0000:0000:0000:0000:0000:0000:0000 */
	static char buf[50+1];
	return (char *)inet_ntop(AF_INET6, addrp, buf, sizeof(buf));
}

char *ebt_ip6_mask_to_string(const struct in6_addr *msk)
{
   	/* /0000:0000:0000:0000:0000:000.000.000.000
	 * /0000:0000:0000:0000:0000:0000:0000:0000 */
	static char buf[51+1];
	if (msk->s6_addr32[0] == 0xFFFFFFFFL && msk->s6_addr32[1] == 0xFFFFFFFFL &&
	    msk->s6_addr32[2] == 0xFFFFFFFFL && msk->s6_addr32[3] == 0xFFFFFFFFL)
		*buf = '\0';
	else
		sprintf(buf, "/%s", ebt_ip6_to_numeric(msk));
	return buf;
}