dhclient - Add 6-byte MAC address to the log entries for DHCP ACK/NAK/OFFER.
[dragonfly.git] / sbin / dhclient / options.c
CommitLineData
bdf60627 1/* $OpenBSD: src/sbin/dhclient/options.c,v 1.37 2009/03/10 23:19:36 krw Exp $ */
846204b6
HT
2
3/* DHCP options parsing and reassembly. */
4
5/*
6 * Copyright (c) 1995, 1996, 1997, 1998 The Internet Software Consortium.
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 *
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of The Internet Software Consortium nor the names
19 * of its contributors may be used to endorse or promote products derived
20 * from this software without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND
23 * CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
24 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
25 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
26 * DISCLAIMED. IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR
27 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
28 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
29 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
30 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
31 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
32 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
33 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 *
36 * This software has been written for the Internet Software Consortium
37 * by Ted Lemon <mellon@fugue.com> in cooperation with Vixie
38 * Enterprises. To learn more about the Internet Software Consortium,
39 * see ``http://www.vix.com/isc''. To learn more about Vixie
40 * Enterprises, see ``http://www.vix.com''.
41 */
42
43#include <ctype.h>
44
45#include "dhcpd.h"
46
47int parse_option_buffer(struct option_data *, unsigned char *, int);
48
49/*
50 * Parse options out of the specified buffer, storing addresses of
51 * option values in options and setting client->options_valid if
52 * no errors are encountered.
53 */
54int
55parse_option_buffer(struct option_data *options, unsigned char *buffer,
56 int length)
57{
58 unsigned char *s, *t, *end = buffer + length;
59 int len, code;
60
61 for (s = buffer; *s != DHO_END && s < end; ) {
62 code = s[0];
63
64 /* Pad options don't have a length - just skip them. */
65 if (code == DHO_PAD) {
66 s++;
67 continue;
68 }
69
70 /*
71 * All options other than DHO_PAD and DHO_END have a
72 * one-byte length field.
73 */
74 if (s + 2 > end)
75 len = 0;
76 else
77 len = s[1];
78
79 /*
80 * If the option claims to extend beyond the end of the buffer
81 * then mark the options buffer bad.
82 */
83 if (s + len + 2 > end) {
84 warning("option %s (%d) larger than buffer.",
85 dhcp_options[code].name, len);
86 warning("rejecting bogus offer.");
87 return (0);
88 }
89 /*
90 * If we haven't seen this option before, just make
91 * space for it and copy it there.
92 */
93 if (!options[code].data) {
94 if (!(t = calloc(1, len + 1)))
95 error("Can't allocate storage for option %s.",
96 dhcp_options[code].name);
97 /*
98 * Copy and NUL-terminate the option (in case
99 * it's an ASCII string).
100 */
101 memcpy(t, &s[2], len);
102 t[len] = 0;
103 options[code].len = len;
104 options[code].data = t;
105 } else {
106 /*
107 * If it's a repeat, concatenate it to whatever
108 * we last saw. This is really only required
109 * for clients, but what the heck...
110 */
111 t = calloc(1, len + options[code].len + 1);
112 if (!t)
113 error("Can't expand storage for option %s.",
114 dhcp_options[code].name);
115 memcpy(t, options[code].data, options[code].len);
116 memcpy(t + options[code].len, &s[2], len);
117 options[code].len += len;
118 t[options[code].len] = 0;
119 free(options[code].data);
120 options[code].data = t;
121 }
122 s += len + 2;
123 }
124
125 return (1);
126}
127
128/*
129 * Copy as many options as fit in buflen bytes of buf. Return the
130 * offset of the start of the last option copied. A caller can check
131 * to see if it's DHO_END to decide if all the options were copied.
132 */
133int
134cons_options(unsigned char *buf, const int buflen, struct option_data *options)
135{
136 int ix, incr, length, bufix, code, lastopt = -1;
137
138 bzero(buf, buflen);
139
140 if (buflen > 3)
141 memcpy(buf, DHCP_OPTIONS_COOKIE, 4);
142 bufix = 4;
143
144 for (code = DHO_SUBNET_MASK; code < DHO_END; code++) {
145 if (!options[code].data)
146 continue;
147
148 length = options[code].len;
149 if (bufix + length + 2*((length+254)/255) >= buflen)
150 return (lastopt);
151
152 lastopt = bufix;
153 ix = 0;
154
155 while (length) {
156 incr = length > 255 ? 255 : length;
157
158 buf[bufix++] = code;
159 buf[bufix++] = incr;
160 memcpy(buf + bufix, options[code].data + ix, incr);
161
162 length -= incr;
163 ix += incr;
164 bufix += incr;
165 }
166 }
167
168 if (bufix < buflen) {
169 buf[bufix] = DHO_END;
170 lastopt = bufix;
171 }
172
173 return (lastopt);
174}
175
176/*
177 * Format the specified option so that a human can easily read it.
178 */
179char *
180pretty_print_option(unsigned int code, unsigned char *data, int len,
181 int emit_commas, int emit_quotes)
182{
183 static char optbuf[32768]; /* XXX */
184 int hunksize = 0, numhunk = -1, numelem = 0;
185 char fmtbuf[32], *op = optbuf;
186 int i, j, k, opleft = sizeof(optbuf);
187 unsigned char *dp = data;
188 struct in_addr foo;
189 char comma;
190
191 /* Code should be between 0 and 255. */
192 if (code > 255)
193 error("pretty_print_option: bad code %d", code);
194
195 if (emit_commas)
196 comma = ',';
197 else
198 comma = ' ';
199
200 /* Figure out the size of the data. */
201 for (i = 0; dhcp_options[code].format[i]; i++) {
202 if (!numhunk) {
203 warning("%s: Excess information in format string: %s",
204 dhcp_options[code].name,
205 &(dhcp_options[code].format[i]));
206 break;
207 }
208 numelem++;
209 fmtbuf[i] = dhcp_options[code].format[i];
210 switch (dhcp_options[code].format[i]) {
211 case 'A':
212 --numelem;
213 fmtbuf[i] = 0;
214 numhunk = 0;
215 break;
216 case 'X':
217 for (k = 0; k < len; k++)
218 if (!isascii(data[k]) ||
219 !isprint(data[k]))
220 break;
221 if (k == len) {
222 fmtbuf[i] = 't';
223 numhunk = -2;
224 } else {
225 fmtbuf[i] = 'x';
226 hunksize++;
227 comma = ':';
228 numhunk = 0;
229 }
230 fmtbuf[i + 1] = 0;
231 break;
232 case 't':
233 fmtbuf[i] = 't';
234 fmtbuf[i + 1] = 0;
235 numhunk = -2;
236 break;
237 case 'I':
238 case 'l':
239 case 'L':
240 hunksize += 4;
241 break;
242 case 's':
243 case 'S':
244 hunksize += 2;
245 break;
246 case 'b':
247 case 'B':
248 case 'f':
249 hunksize++;
250 break;
251 case 'e':
252 break;
253 default:
254 warning("%s: garbage in format string: %s",
255 dhcp_options[code].name,
256 &(dhcp_options[code].format[i]));
257 break;
258 }
259 }
260
261 /* Check for too few bytes... */
262 if (hunksize > len) {
263 warning("%s: expecting at least %d bytes; got %d",
264 dhcp_options[code].name, hunksize, len);
265 return ("<error>");
266 }
267 /* Check for too many bytes... */
268 if (numhunk == -1 && hunksize < len)
269 warning("%s: %d extra bytes",
270 dhcp_options[code].name, len - hunksize);
271
272 /* If this is an array, compute its size. */
273 if (!numhunk)
274 numhunk = len / hunksize;
275 /* See if we got an exact number of hunks. */
276 if (numhunk > 0 && numhunk * hunksize < len)
277 warning("%s: %d extra bytes at end of array",
278 dhcp_options[code].name, len - numhunk * hunksize);
279
280 /* A one-hunk array prints the same as a single hunk. */
281 if (numhunk < 0)
282 numhunk = 1;
283
284 /* Cycle through the array (or hunk) printing the data. */
285 for (i = 0; i < numhunk; i++) {
286 for (j = 0; j < numelem; j++) {
287 int opcount;
288 size_t oplen;
289 switch (fmtbuf[j]) {
290 case 't':
291 if (emit_quotes) {
292 *op++ = '"';
293 opleft--;
294 }
295 for (; dp < data + len; dp++) {
296 if (!isascii(*dp) ||
297 !isprint(*dp)) {
298 if (dp + 1 != data + len ||
299 *dp != 0) {
300 size_t oplen;
301 snprintf(op, opleft,
302 "\\%03o", *dp);
303 oplen = strlen(op);
304 op += oplen;
305 opleft -= oplen;
306 }
307 } else if (*dp == '"' ||
308 *dp == '\'' ||
309 *dp == '$' ||
310 *dp == '`' ||
311 *dp == '\\') {
312 *op++ = '\\';
313 *op++ = *dp;
314 opleft -= 2;
315 } else {
316 *op++ = *dp;
317 opleft--;
318 }
319 }
320 if (emit_quotes) {
321 *op++ = '"';
322 opleft--;
323 }
324
325 *op = 0;
326 break;
327 case 'I':
328 foo.s_addr = htonl(getULong(dp));
329 opcount = strlcpy(op, inet_ntoa(foo), opleft);
330 if (opcount >= opleft)
331 goto toobig;
332 opleft -= opcount;
333 dp += 4;
334 break;
335 case 'l':
336 opcount = snprintf(op, opleft, "%ld",
337 (long)getLong(dp));
338 if (opcount >= opleft || opcount == -1)
339 goto toobig;
340 opleft -= opcount;
341 dp += 4;
342 break;
343 case 'L':
344 opcount = snprintf(op, opleft, "%ld",
345 (unsigned long)getULong(dp));
346 if (opcount >= opleft || opcount == -1)
347 goto toobig;
348 opleft -= opcount;
349 dp += 4;
350 break;
351 case 's':
352 opcount = snprintf(op, opleft, "%d",
353 getShort(dp));
354 if (opcount >= opleft || opcount == -1)
355 goto toobig;
356 opleft -= opcount;
357 dp += 2;
358 break;
359 case 'S':
360 opcount = snprintf(op, opleft, "%d",
361 getUShort(dp));
362 if (opcount >= opleft || opcount == -1)
363 goto toobig;
364 opleft -= opcount;
365 dp += 2;
366 break;
367 case 'b':
368 opcount = snprintf(op, opleft, "%d",
369 *(char *)dp++);
370 if (opcount >= opleft || opcount == -1)
371 goto toobig;
372 opleft -= opcount;
373 break;
374 case 'B':
375 opcount = snprintf(op, opleft, "%d", *dp++);
376 if (opcount >= opleft || opcount == -1)
377 goto toobig;
378 opleft -= opcount;
379 break;
380 case 'x':
381 opcount = snprintf(op, opleft, "%x", *dp++);
382 if (opcount >= opleft || opcount == -1)
383 goto toobig;
384 opleft -= opcount;
385 break;
386 case 'f':
387 opcount = strlcpy(op,
388 *dp++ ? "true" : "false", opleft);
389 if (opcount >= opleft)
390 goto toobig;
391 opleft -= opcount;
392 break;
393 default:
394 warning("Unexpected format code %c", fmtbuf[j]);
395 }
396 oplen = strlen(op);
397 op += oplen;
398 opleft -= oplen;
399 if (opleft < 1)
400 goto toobig;
401 if (j + 1 < numelem && comma != ':') {
402 *op++ = ' ';
403 opleft--;
404 }
405 }
406 if (i + 1 < numhunk) {
407 *op++ = comma;
408 opleft--;
409 }
410 if (opleft < 1)
411 goto toobig;
412
413 }
414 return (optbuf);
415 toobig:
416 warning("dhcp option too large");
417 return ("<error>");
418}
419
420void
421do_packet(int len, unsigned int from_port, struct iaddr from,
422 struct hardware *hfrom)
423{
424 struct dhcp_packet *packet = &client->packet;
425 struct option_data options[256];
426 struct iaddrlist *ap;
427 void (*handler)(struct iaddr, struct option_data *);
428 char *type;
429 int i, options_valid = 1;
430
431 if (packet->hlen > sizeof(packet->chaddr)) {
432 note("Discarding packet with invalid hlen.");
433 return;
434 }
435
436 /*
437 * Silently drop the packet if the client hardware address in the
438 * packet is not the hardware address of the interface being managed.
439 */
440 if ((ifi->hw_address.hlen != packet->hlen) ||
441 (memcmp(ifi->hw_address.haddr, packet->chaddr, packet->hlen)))
442 return;
443
444 memset(options, 0, sizeof(options));
445
446 if (memcmp(&packet->options, DHCP_OPTIONS_COOKIE, 4) == 0) {
447 /* Parse the BOOTP/DHCP options field. */
448 options_valid = parse_option_buffer(options,
449 &packet->options[4], sizeof(packet->options) - 4);
450
451 /* Only DHCP packets have overload areas for options. */
452 if (options_valid &&
453 options[DHO_DHCP_MESSAGE_TYPE].data &&
454 options[DHO_DHCP_OPTION_OVERLOAD].data) {
455 if (options[DHO_DHCP_OPTION_OVERLOAD].data[0] & 1)
456 options_valid = parse_option_buffer(options,
457 (unsigned char *)packet->file,
458 sizeof(packet->file));
459 if (options_valid &&
460 options[DHO_DHCP_OPTION_OVERLOAD].data[0] & 2)
461 options_valid = parse_option_buffer(options,
462 (unsigned char *)packet->sname,
463 sizeof(packet->sname));
464 }
465 }
466
467 type = "";
468 handler = NULL;
469
470 if (options[DHO_DHCP_MESSAGE_TYPE].data) {
471 /* Always try a DHCP packet, even if a bad option was seen. */
472 switch (options[DHO_DHCP_MESSAGE_TYPE].data[0]) {
473 case DHCPOFFER:
474 handler = dhcpoffer;
475 type = "DHCPOFFER";
476 break;
477 case DHCPNAK:
478 handler = dhcpnak;
479 type = "DHCPNACK";
480 break;
481 case DHCPACK:
482 handler = dhcpack;
483 type = "DHCPACK";
484 break;
485 default:
486 break;
487 }
488 } else if (options_valid && packet->op == BOOTREPLY) {
489 handler = dhcpoffer;
490 type = "BOOTREPLY";
491 }
492
bdf60627
AHJ
493 if (handler && client->xid == client->packet.xid) {
494 if (hfrom->hlen == 6)
495 note("%s from %s (%s)", type, piaddr(from),
496 ether_ntoa((struct ether_addr *)hfrom->haddr));
497 else
498 note("%s from %s", type, piaddr(from));
499 } else
500 handler = NULL;
501
846204b6
HT
502 for (ap = config->reject_list; ap && handler; ap = ap->next)
503 if (addr_eq(from, ap->addr)) {
504 note("%s from %s rejected.", type, piaddr(from));
505 handler = NULL;
506 }
507
508 if (handler)
509 (*handler)(from, options);
510
511 for (i = 0; i < 256; i++)
512 if (options[i].len && options[i].data)
513 free(options[i].data);
514}