1 /* $OpenBSD: options.c,v 1.36 2007/06/02 01:29:11 pvalchev Exp $ */
2 /* $DragonFly: src/sbin/dhclient/options.c,v 1.1 2008/08/30 16:07:58 hasso Exp $ */
4 /* DHCP options parsing and reassembly. */
7 * Copyright (c) 1995, 1996, 1997, 1998 The Internet Software Consortium.
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
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19 * 3. Neither the name of The Internet Software Consortium nor the names
20 * of its contributors may be used to endorse or promote products derived
21 * from this software without specific prior written permission.
23 * THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND
24 * CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
25 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
26 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
27 * DISCLAIMED. IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR
28 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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31 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
32 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
33 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
34 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37 * This software has been written for the Internet Software Consortium
38 * by Ted Lemon <mellon@fugue.com> in cooperation with Vixie
39 * Enterprises. To learn more about the Internet Software Consortium,
40 * see ``http://www.vix.com/isc''. To learn more about Vixie
41 * Enterprises, see ``http://www.vix.com''.
48 int parse_option_buffer(struct option_data *, unsigned char *, int);
51 * Parse options out of the specified buffer, storing addresses of
52 * option values in options and setting client->options_valid if
53 * no errors are encountered.
56 parse_option_buffer(struct option_data *options, unsigned char *buffer,
59 unsigned char *s, *t, *end = buffer + length;
62 for (s = buffer; *s != DHO_END && s < end; ) {
65 /* Pad options don't have a length - just skip them. */
66 if (code == DHO_PAD) {
72 * All options other than DHO_PAD and DHO_END have a
73 * one-byte length field.
81 * If the option claims to extend beyond the end of the buffer
82 * then mark the options buffer bad.
84 if (s + len + 2 > end) {
85 warning("option %s (%d) larger than buffer.",
86 dhcp_options[code].name, len);
87 warning("rejecting bogus offer.");
91 * If we haven't seen this option before, just make
92 * space for it and copy it there.
94 if (!options[code].data) {
95 if (!(t = calloc(1, len + 1)))
96 error("Can't allocate storage for option %s.",
97 dhcp_options[code].name);
99 * Copy and NUL-terminate the option (in case
100 * it's an ASCII string).
102 memcpy(t, &s[2], len);
104 options[code].len = len;
105 options[code].data = t;
108 * If it's a repeat, concatenate it to whatever
109 * we last saw. This is really only required
110 * for clients, but what the heck...
112 t = calloc(1, len + options[code].len + 1);
114 error("Can't expand storage for option %s.",
115 dhcp_options[code].name);
116 memcpy(t, options[code].data, options[code].len);
117 memcpy(t + options[code].len, &s[2], len);
118 options[code].len += len;
119 t[options[code].len] = 0;
120 free(options[code].data);
121 options[code].data = t;
130 * Copy as many options as fit in buflen bytes of buf. Return the
131 * offset of the start of the last option copied. A caller can check
132 * to see if it's DHO_END to decide if all the options were copied.
135 cons_options(unsigned char *buf, const int buflen, struct option_data *options)
137 int ix, incr, length, bufix, code, lastopt = -1;
142 memcpy(buf, DHCP_OPTIONS_COOKIE, 4);
145 for (code = DHO_SUBNET_MASK; code < DHO_END; code++) {
146 if (!options[code].data)
149 length = options[code].len;
150 if (bufix + length + 2*((length+254)/255) >= buflen)
157 incr = length > 255 ? 255 : length;
161 memcpy(buf + bufix, options[code].data + ix, incr);
169 if (bufix < buflen) {
170 buf[bufix] = DHO_END;
178 * Format the specified option so that a human can easily read it.
181 pretty_print_option(unsigned int code, unsigned char *data, int len,
182 int emit_commas, int emit_quotes)
184 static char optbuf[32768]; /* XXX */
185 int hunksize = 0, numhunk = -1, numelem = 0;
186 char fmtbuf[32], *op = optbuf;
187 int i, j, k, opleft = sizeof(optbuf);
188 unsigned char *dp = data;
192 /* Code should be between 0 and 255. */
194 error("pretty_print_option: bad code %d", code);
201 /* Figure out the size of the data. */
202 for (i = 0; dhcp_options[code].format[i]; i++) {
204 warning("%s: Excess information in format string: %s",
205 dhcp_options[code].name,
206 &(dhcp_options[code].format[i]));
210 fmtbuf[i] = dhcp_options[code].format[i];
211 switch (dhcp_options[code].format[i]) {
218 for (k = 0; k < len; k++)
219 if (!isascii(data[k]) ||
255 warning("%s: garbage in format string: %s",
256 dhcp_options[code].name,
257 &(dhcp_options[code].format[i]));
262 /* Check for too few bytes... */
263 if (hunksize > len) {
264 warning("%s: expecting at least %d bytes; got %d",
265 dhcp_options[code].name, hunksize, len);
268 /* Check for too many bytes... */
269 if (numhunk == -1 && hunksize < len)
270 warning("%s: %d extra bytes",
271 dhcp_options[code].name, len - hunksize);
273 /* If this is an array, compute its size. */
275 numhunk = len / hunksize;
276 /* See if we got an exact number of hunks. */
277 if (numhunk > 0 && numhunk * hunksize < len)
278 warning("%s: %d extra bytes at end of array",
279 dhcp_options[code].name, len - numhunk * hunksize);
281 /* A one-hunk array prints the same as a single hunk. */
285 /* Cycle through the array (or hunk) printing the data. */
286 for (i = 0; i < numhunk; i++) {
287 for (j = 0; j < numelem; j++) {
296 for (; dp < data + len; dp++) {
299 if (dp + 1 != data + len ||
308 } else if (*dp == '"' ||
329 foo.s_addr = htonl(getULong(dp));
330 opcount = strlcpy(op, inet_ntoa(foo), opleft);
331 if (opcount >= opleft)
337 opcount = snprintf(op, opleft, "%ld",
339 if (opcount >= opleft || opcount == -1)
345 opcount = snprintf(op, opleft, "%ld",
346 (unsigned long)getULong(dp));
347 if (opcount >= opleft || opcount == -1)
353 opcount = snprintf(op, opleft, "%d",
355 if (opcount >= opleft || opcount == -1)
361 opcount = snprintf(op, opleft, "%d",
363 if (opcount >= opleft || opcount == -1)
369 opcount = snprintf(op, opleft, "%d",
371 if (opcount >= opleft || opcount == -1)
376 opcount = snprintf(op, opleft, "%d", *dp++);
377 if (opcount >= opleft || opcount == -1)
382 opcount = snprintf(op, opleft, "%x", *dp++);
383 if (opcount >= opleft || opcount == -1)
388 opcount = strlcpy(op,
389 *dp++ ? "true" : "false", opleft);
390 if (opcount >= opleft)
395 warning("Unexpected format code %c", fmtbuf[j]);
402 if (j + 1 < numelem && comma != ':') {
407 if (i + 1 < numhunk) {
417 warning("dhcp option too large");
422 do_packet(int len, unsigned int from_port, struct iaddr from,
423 struct hardware *hfrom)
425 struct dhcp_packet *packet = &client->packet;
426 struct option_data options[256];
427 struct iaddrlist *ap;
428 void (*handler)(struct iaddr, struct option_data *);
430 int i, options_valid = 1;
432 if (packet->hlen > sizeof(packet->chaddr)) {
433 note("Discarding packet with invalid hlen.");
438 * Silently drop the packet if the client hardware address in the
439 * packet is not the hardware address of the interface being managed.
441 if ((ifi->hw_address.hlen != packet->hlen) ||
442 (memcmp(ifi->hw_address.haddr, packet->chaddr, packet->hlen)))
445 memset(options, 0, sizeof(options));
447 if (memcmp(&packet->options, DHCP_OPTIONS_COOKIE, 4) == 0) {
448 /* Parse the BOOTP/DHCP options field. */
449 options_valid = parse_option_buffer(options,
450 &packet->options[4], sizeof(packet->options) - 4);
452 /* Only DHCP packets have overload areas for options. */
454 options[DHO_DHCP_MESSAGE_TYPE].data &&
455 options[DHO_DHCP_OPTION_OVERLOAD].data) {
456 if (options[DHO_DHCP_OPTION_OVERLOAD].data[0] & 1)
457 options_valid = parse_option_buffer(options,
458 (unsigned char *)packet->file,
459 sizeof(packet->file));
461 options[DHO_DHCP_OPTION_OVERLOAD].data[0] & 2)
462 options_valid = parse_option_buffer(options,
463 (unsigned char *)packet->sname,
464 sizeof(packet->sname));
471 if (options[DHO_DHCP_MESSAGE_TYPE].data) {
472 /* Always try a DHCP packet, even if a bad option was seen. */
473 switch (options[DHO_DHCP_MESSAGE_TYPE].data[0]) {
489 } else if (options_valid && packet->op == BOOTREPLY) {
494 for (ap = config->reject_list; ap && handler; ap = ap->next)
495 if (addr_eq(from, ap->addr)) {
496 note("%s from %s rejected.", type, piaddr(from));
501 (*handler)(from, options);
503 for (i = 0; i < 256; i++)
504 if (options[i].len && options[i].data)
505 free(options[i].data);