2 * This module implements decoding of AHCP (Ad Hoc Configuration Protocol) based
3 * on draft-chroboczek-ahcp-00 and source code of ahcpd-0.53.
6 * Copyright (c) 2013 The TCPDUMP project
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
21 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
22 * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
24 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
25 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
26 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
28 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
32 #define NETDISSECT_REWORKED
37 #include <tcpdump-stdinc.h>
39 #include "interface.h"
41 #include "addrtoname.h"
43 static const char tstr[] = " [|ahcp]";
44 static const char cstr[] = "(corrupt)";
46 #define AHCP_MAGIC_NUMBER 43
47 #define AHCP_VERSION_1 1
48 #define AHCP1_HEADER_FIX_LEN 24
49 #define AHCP1_BODY_MIN_LEN 4
51 #define AHCP1_MSG_DISCOVER 0
52 #define AHCP1_MSG_OFFER 1
53 #define AHCP1_MSG_REQUEST 2
54 #define AHCP1_MSG_ACK 3
55 #define AHCP1_MSG_NACK 4
56 #define AHCP1_MSG_RELEASE 5
58 static const struct tok ahcp1_msg_str[] = {
59 { AHCP1_MSG_DISCOVER, "Discover" },
60 { AHCP1_MSG_OFFER, "Offer" },
61 { AHCP1_MSG_REQUEST, "Request" },
62 { AHCP1_MSG_ACK, "Ack" },
63 { AHCP1_MSG_NACK, "Nack" },
64 { AHCP1_MSG_RELEASE, "Release" },
68 #define AHCP1_OPT_PAD 0
69 #define AHCP1_OPT_MANDATORY 1
70 #define AHCP1_OPT_ORIGIN_TIME 2
71 #define AHCP1_OPT_EXPIRES 3
72 #define AHCP1_OPT_MY_IPV6_ADDRESS 4
73 #define AHCP1_OPT_MY_IPV4_ADDRESS 5
74 #define AHCP1_OPT_IPV6_PREFIX 6
75 #define AHCP1_OPT_IPV4_PREFIX 7
76 #define AHCP1_OPT_IPV6_ADDRESS 8
77 #define AHCP1_OPT_IPV4_ADDRESS 9
78 #define AHCP1_OPT_IPV6_PREFIX_DELEGATION 10
79 #define AHCP1_OPT_IPV4_PREFIX_DELEGATION 11
80 #define AHCP1_OPT_NAME_SERVER 12
81 #define AHCP1_OPT_NTP_SERVER 13
82 #define AHCP1_OPT_MAX 13
84 static const struct tok ahcp1_opt_str[] = {
85 { AHCP1_OPT_PAD, "Pad" },
86 { AHCP1_OPT_MANDATORY, "Mandatory" },
87 { AHCP1_OPT_ORIGIN_TIME, "Origin Time" },
88 { AHCP1_OPT_EXPIRES, "Expires" },
89 { AHCP1_OPT_MY_IPV6_ADDRESS, "My-IPv6-Address" },
90 { AHCP1_OPT_MY_IPV4_ADDRESS, "My-IPv4-Address" },
91 { AHCP1_OPT_IPV6_PREFIX, "IPv6 Prefix" },
92 { AHCP1_OPT_IPV4_PREFIX, "IPv4 Prefix" },
93 { AHCP1_OPT_IPV6_ADDRESS, "IPv6 Address" },
94 { AHCP1_OPT_IPV4_ADDRESS, "IPv4 Address" },
95 { AHCP1_OPT_IPV6_PREFIX_DELEGATION, "IPv6 Prefix Delegation" },
96 { AHCP1_OPT_IPV4_PREFIX_DELEGATION, "IPv4 Prefix Delegation" },
97 { AHCP1_OPT_NAME_SERVER, "Name Server" },
98 { AHCP1_OPT_NTP_SERVER, "NTP Server" },
103 ahcp_time_print(netdissect_options *ndo, const u_char *cp, const u_char *ep) {
111 t = EXTRACT_32BITS(cp);
112 if (NULL == (tm = gmtime(&t)))
113 ND_PRINT((ndo, ": gmtime() error"));
114 else if (0 == strftime(buf, sizeof(buf), "%Y-%m-%d %H:%M:%S", tm))
115 ND_PRINT((ndo, ": strftime() error"));
117 ND_PRINT((ndo, ": %s UTC", buf));
121 ND_PRINT((ndo, ": %s", cstr));
122 ND_TCHECK2(*cp, ep - cp);
125 ND_PRINT((ndo, "%s", tstr));
130 ahcp_seconds_print(netdissect_options *ndo, const u_char *cp, const u_char *ep) {
134 ND_PRINT((ndo, ": %us", EXTRACT_32BITS(cp)));
138 ND_PRINT((ndo, ": %s", cstr));
139 ND_TCHECK2(*cp, ep - cp);
142 ND_PRINT((ndo, "%s", tstr));
147 ahcp_ipv6_addresses_print(netdissect_options *ndo, const u_char *cp, const u_char *ep) {
148 const char *sep = ": ";
155 ND_PRINT((ndo, "%s%s", sep, ip6addr_string(ndo, cp)));
157 ND_PRINT((ndo, "%s(compiled w/o IPv6)", sep));
165 ND_PRINT((ndo, ": %s", cstr));
166 ND_TCHECK2(*cp, ep - cp);
169 ND_PRINT((ndo, "%s", tstr));
174 ahcp_ipv4_addresses_print(netdissect_options *ndo, const u_char *cp, const u_char *ep) {
175 const char *sep = ": ";
181 ND_PRINT((ndo, "%s%s", sep, ipaddr_string(ndo, cp)));
188 ND_PRINT((ndo, ": %s", cstr));
189 ND_TCHECK2(*cp, ep - cp);
192 ND_PRINT((ndo, "%s", tstr));
197 ahcp_ipv6_prefixes_print(netdissect_options *ndo, const u_char *cp, const u_char *ep) {
198 const char *sep = ": ";
205 ND_PRINT((ndo, "%s%s/%u", sep, ip6addr_string(ndo, cp), *(cp + 16)));
207 ND_PRINT((ndo, "%s(compiled w/o IPv6)/%u", sep, *(cp + 16)));
215 ND_PRINT((ndo, ": %s", cstr));
216 ND_TCHECK2(*cp, ep - cp);
219 ND_PRINT((ndo, "%s", tstr));
224 ahcp_ipv4_prefixes_print(netdissect_options *ndo, const u_char *cp, const u_char *ep) {
225 const char *sep = ": ";
231 ND_PRINT((ndo, "%s%s/%u", sep, ipaddr_string(ndo, cp), *(cp + 4)));
238 ND_PRINT((ndo, ": %s", cstr));
239 ND_TCHECK2(*cp, ep - cp);
242 ND_PRINT((ndo, "%s", tstr));
246 /* Data decoders signal truncated data with -1. */
248 (* const data_decoders[AHCP1_OPT_MAX + 1])(netdissect_options *, const u_char *, const u_char *) = {
249 /* [AHCP1_OPT_PAD] = */ NULL,
250 /* [AHCP1_OPT_MANDATORY] = */ NULL,
251 /* [AHCP1_OPT_ORIGIN_TIME] = */ ahcp_time_print,
252 /* [AHCP1_OPT_EXPIRES] = */ ahcp_seconds_print,
253 /* [AHCP1_OPT_MY_IPV6_ADDRESS] = */ ahcp_ipv6_addresses_print,
254 /* [AHCP1_OPT_MY_IPV4_ADDRESS] = */ ahcp_ipv4_addresses_print,
255 /* [AHCP1_OPT_IPV6_PREFIX] = */ ahcp_ipv6_prefixes_print,
256 /* [AHCP1_OPT_IPV4_PREFIX] = */ NULL,
257 /* [AHCP1_OPT_IPV6_ADDRESS] = */ ahcp_ipv6_addresses_print,
258 /* [AHCP1_OPT_IPV4_ADDRESS] = */ ahcp_ipv4_addresses_print,
259 /* [AHCP1_OPT_IPV6_PREFIX_DELEGATION] = */ ahcp_ipv6_prefixes_print,
260 /* [AHCP1_OPT_IPV4_PREFIX_DELEGATION] = */ ahcp_ipv4_prefixes_print,
261 /* [AHCP1_OPT_NAME_SERVER] = */ ahcp_ipv6_addresses_print,
262 /* [AHCP1_OPT_NTP_SERVER] = */ ahcp_ipv6_addresses_print,
266 ahcp1_options_print(netdissect_options *ndo, const u_char *cp, const u_char *ep) {
267 uint8_t option_no, option_len;
274 ND_PRINT((ndo, "\n\t %s", tok2str(ahcp1_opt_str, "Unknown-%u", option_no)));
275 if (option_no == AHCP1_OPT_PAD || option_no == AHCP1_OPT_MANDATORY)
283 if (cp + option_len > ep)
286 if (option_no <= AHCP1_OPT_MAX && data_decoders[option_no] != NULL) {
287 if (data_decoders[option_no](ndo, cp, cp + option_len) < 0)
288 break; /* truncated and already marked up */
290 ND_PRINT((ndo, " (Length %u)", option_len));
291 ND_TCHECK2(*cp, option_len);
298 ND_PRINT((ndo, " %s", cstr));
299 ND_TCHECK2(*cp, ep - cp);
302 ND_PRINT((ndo, "%s", tstr));
306 ahcp1_body_print(netdissect_options *ndo, const u_char *cp, const u_char *ep) {
310 if (cp + AHCP1_BODY_MIN_LEN > ep)
322 body_len = EXTRACT_16BITS(cp);
325 if (ndo->ndo_vflag) {
326 ND_PRINT((ndo, "\n\t%s", tok2str(ahcp1_msg_str, "Unknown-%u", type)));
328 ND_PRINT((ndo, ", MBZ %u", mbz));
329 ND_PRINT((ndo, ", Length %u", body_len));
331 if (cp + body_len > ep)
335 if (ndo->ndo_vflag >= 2)
336 ahcp1_options_print(ndo, cp, cp + body_len); /* not ep (ignore extra data) */
338 ND_TCHECK2(*cp, body_len);
342 ND_PRINT((ndo, " %s", cstr));
343 ND_TCHECK2(*cp, ep - cp);
346 ND_PRINT((ndo, "%s", tstr));
350 ahcp_print(netdissect_options *ndo, const u_char *cp, const u_int len) {
351 const u_char *ep = cp + len;
354 ND_PRINT((ndo, "AHCP"));
359 if (*cp != AHCP_MAGIC_NUMBER)
367 case AHCP_VERSION_1: {
368 ND_PRINT((ndo, " Version 1"));
369 if (len < AHCP1_HEADER_FIX_LEN)
371 if (!ndo->ndo_vflag) {
372 ND_TCHECK2(*cp, AHCP1_HEADER_FIX_LEN - 2);
373 cp += AHCP1_HEADER_FIX_LEN - 2;
377 ND_PRINT((ndo, "\n\tHopcount %u", *cp));
379 /* Original Hopcount */
381 ND_PRINT((ndo, ", Original Hopcount %u", *cp));
385 ND_PRINT((ndo, ", Nonce 0x%08x", EXTRACT_32BITS(cp)));
389 ND_PRINT((ndo, ", Source Id %s", linkaddr_string(ndo, cp, 0, 8)));
393 ND_PRINT((ndo, ", Destination Id %s", linkaddr_string(ndo, cp, 0, 8)));
397 ahcp1_body_print(ndo, cp, ep);
401 ND_PRINT((ndo, " Version %u (unknown)", version));
407 ND_PRINT((ndo, " %s", cstr));
408 ND_TCHECK2(*cp, ep - cp);
411 ND_PRINT((ndo, "%s", tstr));