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 #include <config.h>
33
34 #include "netdissect-stdinc.h"
35
36 #define ND_LONGJMP_FROM_TCHECK
37 #include "netdissect.h"
38 #include "extract.h"
39 #include "addrtoname.h"
40
41
42 #define AHCP_MAGIC_NUMBER 43
43 #define AHCP_VERSION_1 1
44 #define AHCP1_HEADER_FIX_LEN 24
45 #define AHCP1_BODY_MIN_LEN 4
46
47 #define AHCP1_MSG_DISCOVER 0
48 #define AHCP1_MSG_OFFER 1
49 #define AHCP1_MSG_REQUEST 2
50 #define AHCP1_MSG_ACK 3
51 #define AHCP1_MSG_NACK 4
52 #define AHCP1_MSG_RELEASE 5
53
54 static const struct tok ahcp1_msg_str[] = {
55 { AHCP1_MSG_DISCOVER, "Discover" },
56 { AHCP1_MSG_OFFER, "Offer" },
57 { AHCP1_MSG_REQUEST, "Request" },
58 { AHCP1_MSG_ACK, "Ack" },
59 { AHCP1_MSG_NACK, "Nack" },
60 { AHCP1_MSG_RELEASE, "Release" },
61 { 0, NULL }
62 };
63
64 #define AHCP1_OPT_PAD 0
65 #define AHCP1_OPT_MANDATORY 1
66 #define AHCP1_OPT_ORIGIN_TIME 2
67 #define AHCP1_OPT_EXPIRES 3
68 #define AHCP1_OPT_MY_IPV6_ADDRESS 4
69 #define AHCP1_OPT_MY_IPV4_ADDRESS 5
70 #define AHCP1_OPT_IPV6_PREFIX 6
71 #define AHCP1_OPT_IPV4_PREFIX 7
72 #define AHCP1_OPT_IPV6_ADDRESS 8
73 #define AHCP1_OPT_IPV4_ADDRESS 9
74 #define AHCP1_OPT_IPV6_PREFIX_DELEGATION 10
75 #define AHCP1_OPT_IPV4_PREFIX_DELEGATION 11
76 #define AHCP1_OPT_NAME_SERVER 12
77 #define AHCP1_OPT_NTP_SERVER 13
78 #define AHCP1_OPT_MAX 13
79
80 static const struct tok ahcp1_opt_str[] = {
81 { AHCP1_OPT_PAD, "Pad" },
82 { AHCP1_OPT_MANDATORY, "Mandatory" },
83 { AHCP1_OPT_ORIGIN_TIME, "Origin Time" },
84 { AHCP1_OPT_EXPIRES, "Expires" },
85 { AHCP1_OPT_MY_IPV6_ADDRESS, "My-IPv6-Address" },
86 { AHCP1_OPT_MY_IPV4_ADDRESS, "My-IPv4-Address" },
87 { AHCP1_OPT_IPV6_PREFIX, "IPv6 Prefix" },
88 { AHCP1_OPT_IPV4_PREFIX, "IPv4 Prefix" },
89 { AHCP1_OPT_IPV6_ADDRESS, "IPv6 Address" },
90 { AHCP1_OPT_IPV4_ADDRESS, "IPv4 Address" },
91 { AHCP1_OPT_IPV6_PREFIX_DELEGATION, "IPv6 Prefix Delegation" },
92 { AHCP1_OPT_IPV4_PREFIX_DELEGATION, "IPv4 Prefix Delegation" },
93 { AHCP1_OPT_NAME_SERVER, "Name Server" },
94 { AHCP1_OPT_NTP_SERVER, "NTP Server" },
95 { 0, NULL }
96 };
97
98 static void
ahcp_time_print(netdissect_options * ndo,const u_char * cp,uint8_t len)99 ahcp_time_print(netdissect_options *ndo,
100 const u_char *cp, uint8_t len)
101 {
102 time_t t;
103 char buf[sizeof("-yyyyyyyyyy-mm-dd hh:mm:ss UTC")];
104
105 if (len != 4)
106 goto invalid;
107 t = GET_BE_U_4(cp);
108 ND_PRINT(": %s",
109 nd_format_time(buf, sizeof(buf), "%Y-%m-%d %H:%M:%S UTC",
110 gmtime(&t)));
111 return;
112
113 invalid:
114 nd_print_invalid(ndo);
115 ND_TCHECK_LEN(cp, len);
116 }
117
118 static void
ahcp_seconds_print(netdissect_options * ndo,const u_char * cp,uint8_t len)119 ahcp_seconds_print(netdissect_options *ndo,
120 const u_char *cp, uint8_t len)
121 {
122 if (len != 4)
123 goto invalid;
124 ND_PRINT(": %us", GET_BE_U_4(cp));
125 return;
126
127 invalid:
128 nd_print_invalid(ndo);
129 ND_TCHECK_LEN(cp, len);
130 }
131
132 static void
ahcp_ipv6_addresses_print(netdissect_options * ndo,const u_char * cp,uint8_t len)133 ahcp_ipv6_addresses_print(netdissect_options *ndo,
134 const u_char *cp, uint8_t len)
135 {
136 const char *sep = ": ";
137
138 while (len) {
139 if (len < 16)
140 goto invalid;
141 ND_PRINT("%s%s", sep, GET_IP6ADDR_STRING(cp));
142 cp += 16;
143 len -= 16;
144 sep = ", ";
145 }
146 return;
147
148 invalid:
149 nd_print_invalid(ndo);
150 ND_TCHECK_LEN(cp, len);
151 }
152
153 static void
ahcp_ipv4_addresses_print(netdissect_options * ndo,const u_char * cp,uint8_t len)154 ahcp_ipv4_addresses_print(netdissect_options *ndo,
155 const u_char *cp, uint8_t len)
156 {
157 const char *sep = ": ";
158
159 while (len) {
160 if (len < 4)
161 goto invalid;
162 ND_PRINT("%s%s", sep, GET_IPADDR_STRING(cp));
163 cp += 4;
164 len -= 4;
165 sep = ", ";
166 }
167 return;
168
169 invalid:
170 nd_print_invalid(ndo);
171 ND_TCHECK_LEN(cp, len);
172 }
173
174 static void
ahcp_ipv6_prefixes_print(netdissect_options * ndo,const u_char * cp,uint8_t len)175 ahcp_ipv6_prefixes_print(netdissect_options *ndo,
176 const u_char *cp, uint8_t len)
177 {
178 const char *sep = ": ";
179
180 while (len) {
181 if (len < 17)
182 goto invalid;
183 ND_PRINT("%s%s/%u", sep, GET_IP6ADDR_STRING(cp), GET_U_1(cp + 16));
184 cp += 17;
185 len -= 17;
186 sep = ", ";
187 }
188 return;
189
190 invalid:
191 nd_print_invalid(ndo);
192 ND_TCHECK_LEN(cp, len);
193 }
194
195 static void
ahcp_ipv4_prefixes_print(netdissect_options * ndo,const u_char * cp,uint8_t len)196 ahcp_ipv4_prefixes_print(netdissect_options *ndo,
197 const u_char *cp, uint8_t len)
198 {
199 const char *sep = ": ";
200
201 while (len) {
202 if (len < 5)
203 goto invalid;
204 ND_PRINT("%s%s/%u", sep, GET_IPADDR_STRING(cp), GET_U_1(cp + 4));
205 cp += 5;
206 len -= 5;
207 sep = ", ";
208 }
209 return;
210
211 invalid:
212 nd_print_invalid(ndo);
213 ND_TCHECK_LEN(cp, len);
214 }
215
216 static void
217 (* const data_decoders[AHCP1_OPT_MAX + 1])(netdissect_options *, const u_char *, uint8_t) = {
218 /* [AHCP1_OPT_PAD] = */ NULL,
219 /* [AHCP1_OPT_MANDATORY] = */ NULL,
220 /* [AHCP1_OPT_ORIGIN_TIME] = */ ahcp_time_print,
221 /* [AHCP1_OPT_EXPIRES] = */ ahcp_seconds_print,
222 /* [AHCP1_OPT_MY_IPV6_ADDRESS] = */ ahcp_ipv6_addresses_print,
223 /* [AHCP1_OPT_MY_IPV4_ADDRESS] = */ ahcp_ipv4_addresses_print,
224 /* [AHCP1_OPT_IPV6_PREFIX] = */ ahcp_ipv6_prefixes_print,
225 /* [AHCP1_OPT_IPV4_PREFIX] = */ NULL,
226 /* [AHCP1_OPT_IPV6_ADDRESS] = */ ahcp_ipv6_addresses_print,
227 /* [AHCP1_OPT_IPV4_ADDRESS] = */ ahcp_ipv4_addresses_print,
228 /* [AHCP1_OPT_IPV6_PREFIX_DELEGATION] = */ ahcp_ipv6_prefixes_print,
229 /* [AHCP1_OPT_IPV4_PREFIX_DELEGATION] = */ ahcp_ipv4_prefixes_print,
230 /* [AHCP1_OPT_NAME_SERVER] = */ ahcp_ipv6_addresses_print,
231 /* [AHCP1_OPT_NTP_SERVER] = */ ahcp_ipv6_addresses_print,
232 };
233
234 static void
ahcp1_options_print(netdissect_options * ndo,const u_char * cp,uint16_t len)235 ahcp1_options_print(netdissect_options *ndo,
236 const u_char *cp, uint16_t len)
237 {
238 while (len) {
239 uint8_t option_no, option_len;
240
241 /* Option no */
242 option_no = GET_U_1(cp);
243 cp += 1;
244 len -= 1;
245 ND_PRINT("\n\t %s", tok2str(ahcp1_opt_str, "Unknown-%u", option_no));
246 if (option_no == AHCP1_OPT_PAD || option_no == AHCP1_OPT_MANDATORY)
247 continue;
248 /* Length */
249 if (!len)
250 goto invalid;
251 option_len = GET_U_1(cp);
252 cp += 1;
253 len -= 1;
254 if (option_len > len)
255 goto invalid;
256 /* Value */
257 if (option_no <= AHCP1_OPT_MAX && data_decoders[option_no] != NULL) {
258 data_decoders[option_no](ndo, cp, option_len);
259 } else {
260 ND_PRINT(" (Length %u)", option_len);
261 ND_TCHECK_LEN(cp, option_len);
262 }
263 cp += option_len;
264 len -= option_len;
265 }
266 return;
267
268 invalid:
269 nd_print_invalid(ndo);
270 ND_TCHECK_LEN(cp, len);
271 }
272
273 static void
ahcp1_body_print(netdissect_options * ndo,const u_char * cp,u_int len)274 ahcp1_body_print(netdissect_options *ndo,
275 const u_char *cp, u_int len)
276 {
277 uint8_t type, mbz;
278 uint16_t body_len;
279
280 if (len < AHCP1_BODY_MIN_LEN)
281 goto invalid;
282 /* Type */
283 type = GET_U_1(cp);
284 cp += 1;
285 len -= 1;
286 /* MBZ */
287 mbz = GET_U_1(cp);
288 cp += 1;
289 len -= 1;
290 /* Length */
291 body_len = GET_BE_U_2(cp);
292 cp += 2;
293 len -= 2;
294
295 if (ndo->ndo_vflag) {
296 ND_PRINT("\n\t%s", tok2str(ahcp1_msg_str, "Unknown-%u", type));
297 if (mbz != 0)
298 ND_PRINT(", MBZ %u", mbz);
299 ND_PRINT(", Length %u", body_len);
300 }
301 if (body_len > len)
302 goto invalid;
303
304 /* Options */
305 /* Here use "body_len", not "len" (ignore any extra data). */
306 if (ndo->ndo_vflag >= 2)
307 ahcp1_options_print(ndo, cp, body_len);
308 else
309 ND_TCHECK_LEN(cp, body_len);
310 return;
311
312 invalid:
313 nd_print_invalid(ndo);
314 ND_TCHECK_LEN(cp, len);
315
316 }
317
318 void
ahcp_print(netdissect_options * ndo,const u_char * cp,u_int len)319 ahcp_print(netdissect_options *ndo,
320 const u_char *cp, u_int len)
321 {
322 uint8_t version;
323
324 ndo->ndo_protocol = "ahcp";
325 nd_print_protocol_caps(ndo);
326 if (len < 2)
327 goto invalid;
328 /* Magic */
329 if (GET_U_1(cp) != AHCP_MAGIC_NUMBER)
330 goto invalid;
331 cp += 1;
332 len -= 1;
333 /* Version */
334 version = GET_U_1(cp);
335 cp += 1;
336 len -= 1;
337 switch (version) {
338 case AHCP_VERSION_1: {
339 ND_PRINT(" Version 1");
340 if (len < AHCP1_HEADER_FIX_LEN - 2)
341 goto invalid;
342 if (!ndo->ndo_vflag) {
343 ND_TCHECK_LEN(cp, AHCP1_HEADER_FIX_LEN - 2);
344 cp += AHCP1_HEADER_FIX_LEN - 2;
345 len -= AHCP1_HEADER_FIX_LEN - 2;
346 } else {
347 /* Hopcount */
348 ND_PRINT("\n\tHopcount %u", GET_U_1(cp));
349 cp += 1;
350 len -= 1;
351 /* Original Hopcount */
352 ND_PRINT(", Original Hopcount %u", GET_U_1(cp));
353 cp += 1;
354 len -= 1;
355 /* Nonce */
356 ND_PRINT(", Nonce 0x%08x", GET_BE_U_4(cp));
357 cp += 4;
358 len -= 4;
359 /* Source Id */
360 ND_PRINT(", Source Id %s", GET_LINKADDR_STRING(cp, LINKADDR_OTHER, 8));
361 cp += 8;
362 len -= 8;
363 /* Destination Id */
364 ND_PRINT(", Destination Id %s", GET_LINKADDR_STRING(cp, LINKADDR_OTHER, 8));
365 cp += 8;
366 len -= 8;
367 }
368 /* Body */
369 ahcp1_body_print(ndo, cp, len);
370 break;
371 }
372 default:
373 ND_PRINT(" Version %u (unknown)", version);
374 ND_TCHECK_LEN(cp, len);
375 break;
376 }
377 return;
378
379 invalid:
380 nd_print_invalid(ndo);
381 ND_TCHECK_LEN(cp, len);
382 }
383