1 /*
2 * Copyright (c) 2013 The TCPDUMP project
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
15 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
16 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
17 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
18 * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
20 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
21 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
22 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
24 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
25 * POSSIBILITY OF SUCH DAMAGE.
26 */
27
28 /* \summary: Ad Hoc Configuration Protocol (AHCP) printer */
29
30 /* Based on draft-chroboczek-ahcp-00 and source code of ahcpd-0.53 */
31
32 #ifdef HAVE_CONFIG_H
33 #include "config.h"
34 #endif
35
36 #include <netdissect-stdinc.h>
37
38 #include "netdissect.h"
39 #include "extract.h"
40 #include "addrtoname.h"
41
42 static const char tstr[] = " [|ahcp]";
43
44 #define AHCP_MAGIC_NUMBER 43
45 #define AHCP_VERSION_1 1
46 #define AHCP1_HEADER_FIX_LEN 24
47 #define AHCP1_BODY_MIN_LEN 4
48
49 #define AHCP1_MSG_DISCOVER 0
50 #define AHCP1_MSG_OFFER 1
51 #define AHCP1_MSG_REQUEST 2
52 #define AHCP1_MSG_ACK 3
53 #define AHCP1_MSG_NACK 4
54 #define AHCP1_MSG_RELEASE 5
55
56 static const struct tok ahcp1_msg_str[] = {
57 { AHCP1_MSG_DISCOVER, "Discover" },
58 { AHCP1_MSG_OFFER, "Offer" },
59 { AHCP1_MSG_REQUEST, "Request" },
60 { AHCP1_MSG_ACK, "Ack" },
61 { AHCP1_MSG_NACK, "Nack" },
62 { AHCP1_MSG_RELEASE, "Release" },
63 { 0, NULL }
64 };
65
66 #define AHCP1_OPT_PAD 0
67 #define AHCP1_OPT_MANDATORY 1
68 #define AHCP1_OPT_ORIGIN_TIME 2
69 #define AHCP1_OPT_EXPIRES 3
70 #define AHCP1_OPT_MY_IPV6_ADDRESS 4
71 #define AHCP1_OPT_MY_IPV4_ADDRESS 5
72 #define AHCP1_OPT_IPV6_PREFIX 6
73 #define AHCP1_OPT_IPV4_PREFIX 7
74 #define AHCP1_OPT_IPV6_ADDRESS 8
75 #define AHCP1_OPT_IPV4_ADDRESS 9
76 #define AHCP1_OPT_IPV6_PREFIX_DELEGATION 10
77 #define AHCP1_OPT_IPV4_PREFIX_DELEGATION 11
78 #define AHCP1_OPT_NAME_SERVER 12
79 #define AHCP1_OPT_NTP_SERVER 13
80 #define AHCP1_OPT_MAX 13
81
82 static const struct tok ahcp1_opt_str[] = {
83 { AHCP1_OPT_PAD, "Pad" },
84 { AHCP1_OPT_MANDATORY, "Mandatory" },
85 { AHCP1_OPT_ORIGIN_TIME, "Origin Time" },
86 { AHCP1_OPT_EXPIRES, "Expires" },
87 { AHCP1_OPT_MY_IPV6_ADDRESS, "My-IPv6-Address" },
88 { AHCP1_OPT_MY_IPV4_ADDRESS, "My-IPv4-Address" },
89 { AHCP1_OPT_IPV6_PREFIX, "IPv6 Prefix" },
90 { AHCP1_OPT_IPV4_PREFIX, "IPv4 Prefix" },
91 { AHCP1_OPT_IPV6_ADDRESS, "IPv6 Address" },
92 { AHCP1_OPT_IPV4_ADDRESS, "IPv4 Address" },
93 { AHCP1_OPT_IPV6_PREFIX_DELEGATION, "IPv6 Prefix Delegation" },
94 { AHCP1_OPT_IPV4_PREFIX_DELEGATION, "IPv4 Prefix Delegation" },
95 { AHCP1_OPT_NAME_SERVER, "Name Server" },
96 { AHCP1_OPT_NTP_SERVER, "NTP Server" },
97 { 0, NULL }
98 };
99
100 static int
ahcp_time_print(netdissect_options * ndo,const u_char * cp,const u_char * ep)101 ahcp_time_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
102 {
103 time_t t;
104 struct tm *tm;
105 char buf[BUFSIZE];
106
107 if (cp + 4 != ep)
108 goto invalid;
109 ND_TCHECK2(*cp, 4);
110 t = EXTRACT_32BITS(cp);
111 if (NULL == (tm = gmtime(&t)))
112 ND_PRINT((ndo, ": gmtime() error"));
113 else if (0 == strftime(buf, sizeof(buf), "%Y-%m-%d %H:%M:%S", tm))
114 ND_PRINT((ndo, ": strftime() error"));
115 else
116 ND_PRINT((ndo, ": %s UTC", buf));
117 return 0;
118
119 invalid:
120 ND_PRINT((ndo, "%s", istr));
121 ND_TCHECK2(*cp, ep - cp);
122 return 0;
123 trunc:
124 ND_PRINT((ndo, "%s", tstr));
125 return -1;
126 }
127
128 static int
ahcp_seconds_print(netdissect_options * ndo,const u_char * cp,const u_char * ep)129 ahcp_seconds_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
130 {
131 if (cp + 4 != ep)
132 goto invalid;
133 ND_TCHECK2(*cp, 4);
134 ND_PRINT((ndo, ": %us", EXTRACT_32BITS(cp)));
135 return 0;
136
137 invalid:
138 ND_PRINT((ndo, "%s", istr));
139 ND_TCHECK2(*cp, ep - cp);
140 return 0;
141 trunc:
142 ND_PRINT((ndo, "%s", tstr));
143 return -1;
144 }
145
146 static int
ahcp_ipv6_addresses_print(netdissect_options * ndo,const u_char * cp,const u_char * ep)147 ahcp_ipv6_addresses_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
148 {
149 const char *sep = ": ";
150
151 while (cp < ep) {
152 if (cp + 16 > ep)
153 goto invalid;
154 ND_TCHECK2(*cp, 16);
155 ND_PRINT((ndo, "%s%s", sep, ip6addr_string(ndo, cp)));
156 cp += 16;
157 sep = ", ";
158 }
159 return 0;
160
161 invalid:
162 ND_PRINT((ndo, "%s", istr));
163 ND_TCHECK2(*cp, ep - cp);
164 return 0;
165 trunc:
166 ND_PRINT((ndo, "%s", tstr));
167 return -1;
168 }
169
170 static int
ahcp_ipv4_addresses_print(netdissect_options * ndo,const u_char * cp,const u_char * ep)171 ahcp_ipv4_addresses_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
172 {
173 const char *sep = ": ";
174
175 while (cp < ep) {
176 if (cp + 4 > ep)
177 goto invalid;
178 ND_TCHECK2(*cp, 4);
179 ND_PRINT((ndo, "%s%s", sep, ipaddr_string(ndo, cp)));
180 cp += 4;
181 sep = ", ";
182 }
183 return 0;
184
185 invalid:
186 ND_PRINT((ndo, "%s", istr));
187 ND_TCHECK2(*cp, ep - cp);
188 return 0;
189 trunc:
190 ND_PRINT((ndo, "%s", tstr));
191 return -1;
192 }
193
194 static int
ahcp_ipv6_prefixes_print(netdissect_options * ndo,const u_char * cp,const u_char * ep)195 ahcp_ipv6_prefixes_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
196 {
197 const char *sep = ": ";
198
199 while (cp < ep) {
200 if (cp + 17 > ep)
201 goto invalid;
202 ND_TCHECK2(*cp, 17);
203 ND_PRINT((ndo, "%s%s/%u", sep, ip6addr_string(ndo, cp), *(cp + 16)));
204 cp += 17;
205 sep = ", ";
206 }
207 return 0;
208
209 invalid:
210 ND_PRINT((ndo, "%s", istr));
211 ND_TCHECK2(*cp, ep - cp);
212 return 0;
213 trunc:
214 ND_PRINT((ndo, "%s", tstr));
215 return -1;
216 }
217
218 static int
ahcp_ipv4_prefixes_print(netdissect_options * ndo,const u_char * cp,const u_char * ep)219 ahcp_ipv4_prefixes_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
220 {
221 const char *sep = ": ";
222
223 while (cp < ep) {
224 if (cp + 5 > ep)
225 goto invalid;
226 ND_TCHECK2(*cp, 5);
227 ND_PRINT((ndo, "%s%s/%u", sep, ipaddr_string(ndo, cp), *(cp + 4)));
228 cp += 5;
229 sep = ", ";
230 }
231 return 0;
232
233 invalid:
234 ND_PRINT((ndo, "%s", istr));
235 ND_TCHECK2(*cp, ep - cp);
236 return 0;
237 trunc:
238 ND_PRINT((ndo, "%s", tstr));
239 return -1;
240 }
241
242 /* Data decoders signal truncated data with -1. */
243 static int
244 (* const data_decoders[AHCP1_OPT_MAX + 1])(netdissect_options *, const u_char *, const u_char *) = {
245 /* [AHCP1_OPT_PAD] = */ NULL,
246 /* [AHCP1_OPT_MANDATORY] = */ NULL,
247 /* [AHCP1_OPT_ORIGIN_TIME] = */ ahcp_time_print,
248 /* [AHCP1_OPT_EXPIRES] = */ ahcp_seconds_print,
249 /* [AHCP1_OPT_MY_IPV6_ADDRESS] = */ ahcp_ipv6_addresses_print,
250 /* [AHCP1_OPT_MY_IPV4_ADDRESS] = */ ahcp_ipv4_addresses_print,
251 /* [AHCP1_OPT_IPV6_PREFIX] = */ ahcp_ipv6_prefixes_print,
252 /* [AHCP1_OPT_IPV4_PREFIX] = */ NULL,
253 /* [AHCP1_OPT_IPV6_ADDRESS] = */ ahcp_ipv6_addresses_print,
254 /* [AHCP1_OPT_IPV4_ADDRESS] = */ ahcp_ipv4_addresses_print,
255 /* [AHCP1_OPT_IPV6_PREFIX_DELEGATION] = */ ahcp_ipv6_prefixes_print,
256 /* [AHCP1_OPT_IPV4_PREFIX_DELEGATION] = */ ahcp_ipv4_prefixes_print,
257 /* [AHCP1_OPT_NAME_SERVER] = */ ahcp_ipv6_addresses_print,
258 /* [AHCP1_OPT_NTP_SERVER] = */ ahcp_ipv6_addresses_print,
259 };
260
261 static void
ahcp1_options_print(netdissect_options * ndo,const u_char * cp,const u_char * ep)262 ahcp1_options_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
263 {
264 uint8_t option_no, option_len;
265
266 while (cp < ep) {
267 /* Option no */
268 ND_TCHECK2(*cp, 1);
269 option_no = *cp;
270 cp += 1;
271 ND_PRINT((ndo, "\n\t %s", tok2str(ahcp1_opt_str, "Unknown-%u", option_no)));
272 if (option_no == AHCP1_OPT_PAD || option_no == AHCP1_OPT_MANDATORY)
273 continue;
274 /* Length */
275 if (cp + 1 > ep)
276 goto invalid;
277 ND_TCHECK2(*cp, 1);
278 option_len = *cp;
279 cp += 1;
280 if (cp + option_len > ep)
281 goto invalid;
282 /* Value */
283 if (option_no <= AHCP1_OPT_MAX && data_decoders[option_no] != NULL) {
284 if (data_decoders[option_no](ndo, cp, cp + option_len) < 0)
285 break; /* truncated and already marked up */
286 } else {
287 ND_PRINT((ndo, " (Length %u)", option_len));
288 ND_TCHECK2(*cp, option_len);
289 }
290 cp += option_len;
291 }
292 return;
293
294 invalid:
295 ND_PRINT((ndo, "%s", istr));
296 ND_TCHECK2(*cp, ep - cp);
297 return;
298 trunc:
299 ND_PRINT((ndo, "%s", tstr));
300 }
301
302 static void
ahcp1_body_print(netdissect_options * ndo,const u_char * cp,const u_char * ep)303 ahcp1_body_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
304 {
305 uint8_t type, mbz;
306 uint16_t body_len;
307
308 if (cp + AHCP1_BODY_MIN_LEN > ep)
309 goto invalid;
310 /* Type */
311 ND_TCHECK2(*cp, 1);
312 type = *cp;
313 cp += 1;
314 /* MBZ */
315 ND_TCHECK2(*cp, 1);
316 mbz = *cp;
317 cp += 1;
318 /* Length */
319 ND_TCHECK2(*cp, 2);
320 body_len = EXTRACT_16BITS(cp);
321 cp += 2;
322
323 if (ndo->ndo_vflag) {
324 ND_PRINT((ndo, "\n\t%s", tok2str(ahcp1_msg_str, "Unknown-%u", type)));
325 if (mbz != 0)
326 ND_PRINT((ndo, ", MBZ %u", mbz));
327 ND_PRINT((ndo, ", Length %u", body_len));
328 }
329 if (cp + body_len > ep)
330 goto invalid;
331
332 /* Options */
333 if (ndo->ndo_vflag >= 2)
334 ahcp1_options_print(ndo, cp, cp + body_len); /* not ep (ignore extra data) */
335 else
336 ND_TCHECK2(*cp, body_len);
337 return;
338
339 invalid:
340 ND_PRINT((ndo, "%s", istr));
341 ND_TCHECK2(*cp, ep - cp);
342 return;
343 trunc:
344 ND_PRINT((ndo, "%s", tstr));
345 }
346
347 void
ahcp_print(netdissect_options * ndo,const u_char * cp,const u_int len)348 ahcp_print(netdissect_options *ndo, const u_char *cp, const u_int len)
349 {
350 const u_char *ep = cp + len;
351 uint8_t version;
352
353 ND_PRINT((ndo, "AHCP"));
354 if (len < 2)
355 goto invalid;
356 /* Magic */
357 ND_TCHECK2(*cp, 1);
358 if (*cp != AHCP_MAGIC_NUMBER)
359 goto invalid;
360 cp += 1;
361 /* Version */
362 ND_TCHECK2(*cp, 1);
363 version = *cp;
364 cp += 1;
365 switch (version) {
366 case AHCP_VERSION_1: {
367 ND_PRINT((ndo, " Version 1"));
368 if (len < AHCP1_HEADER_FIX_LEN)
369 goto invalid;
370 if (!ndo->ndo_vflag) {
371 ND_TCHECK2(*cp, AHCP1_HEADER_FIX_LEN - 2);
372 cp += AHCP1_HEADER_FIX_LEN - 2;
373 } else {
374 /* Hopcount */
375 ND_TCHECK2(*cp, 1);
376 ND_PRINT((ndo, "\n\tHopcount %u", *cp));
377 cp += 1;
378 /* Original Hopcount */
379 ND_TCHECK2(*cp, 1);
380 ND_PRINT((ndo, ", Original Hopcount %u", *cp));
381 cp += 1;
382 /* Nonce */
383 ND_TCHECK2(*cp, 4);
384 ND_PRINT((ndo, ", Nonce 0x%08x", EXTRACT_32BITS(cp)));
385 cp += 4;
386 /* Source Id */
387 ND_TCHECK2(*cp, 8);
388 ND_PRINT((ndo, ", Source Id %s", linkaddr_string(ndo, cp, 0, 8)));
389 cp += 8;
390 /* Destination Id */
391 ND_TCHECK2(*cp, 8);
392 ND_PRINT((ndo, ", Destination Id %s", linkaddr_string(ndo, cp, 0, 8)));
393 cp += 8;
394 }
395 /* Body */
396 ahcp1_body_print(ndo, cp, ep);
397 break;
398 }
399 default:
400 ND_PRINT((ndo, " Version %u (unknown)", version));
401 break;
402 }
403 return;
404
405 invalid:
406 ND_PRINT((ndo, "%s", istr));
407 ND_TCHECK2(*cp, ep - cp);
408 return;
409 trunc:
410 ND_PRINT((ndo, "%s", tstr));
411 }
412