contrib/tcpdump/print-ahcp.c

   1 /*
   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.
   4  *
   5  *
   6  * Copyright (c) 2013 The TCPDUMP project
   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  * 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.
  17  *
  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.
  30  */
  31
  32 #define NETDISSECT_REWORKED
  33 #ifdef HAVE_CONFIG_H
  34 #include "config.h"
  35 #endif
  36
  37 #include <tcpdump-stdinc.h>
  38
  39 #include "interface.h"
  40 #include "extract.h"
  41 #include "addrtoname.h"
  42
  43 static const char tstr[] = " [|ahcp]";
  44 static const char cstr[] = "(corrupt)";
  45
  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
  50
  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
  57
  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"  },
  65         { 0, NULL }
  66 };
  67
  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
  83
  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"             },
  99         { 0, NULL }
 100 };
 101
 102 static int
 103 ahcp_time_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
 104 {
 105         time_t t;
 106         struct tm *tm;
 107         char buf[BUFSIZE];
 108
 109         if (cp + 4 != ep)
 110                 goto corrupt;
 111         ND_TCHECK2(*cp, 4);
 112         t = EXTRACT_32BITS(cp);
 113         if (NULL == (tm = gmtime(&t)))
 114                 ND_PRINT((ndo, ": gmtime() error"));
 115         else if (0 == strftime(buf, sizeof(buf), "%Y-%m-%d %H:%M:%S", tm))
 116                 ND_PRINT((ndo, ": strftime() error"));
 117         else
 118                 ND_PRINT((ndo, ": %s UTC", buf));
 119         return 0;
 120
 121 corrupt:
 122         ND_PRINT((ndo, ": %s", cstr));
 123         ND_TCHECK2(*cp, ep - cp);
 124         return 0;
 125 trunc:
 126         ND_PRINT((ndo, "%s", tstr));
 127         return -1;
 128 }
 129
 130 static int
 131 ahcp_seconds_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
 132 {
 133         if (cp + 4 != ep)
 134                 goto corrupt;
 135         ND_TCHECK2(*cp, 4);
 136         ND_PRINT((ndo, ": %us", EXTRACT_32BITS(cp)));
 137         return 0;
 138
 139 corrupt:
 140         ND_PRINT((ndo, ": %s", cstr));
 141         ND_TCHECK2(*cp, ep - cp);
 142         return 0;
 143 trunc:
 144         ND_PRINT((ndo, "%s", tstr));
 145         return -1;
 146 }
 147
 148 static int
 149 ahcp_ipv6_addresses_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
 150 {
 151         const char *sep = ": ";
 152
 153         while (cp < ep) {
 154                 if (cp + 16 > ep)
 155                         goto corrupt;
 156                 ND_TCHECK2(*cp, 16);
 157 #ifdef INET6
 158                 ND_PRINT((ndo, "%s%s", sep, ip6addr_string(ndo, cp)));
 159 #else
 160                 ND_PRINT((ndo, "%s(compiled w/o IPv6)", sep));
 161 #endif /* INET6 */
 162                 cp += 16;
 163                 sep = ", ";
 164         }
 165         return 0;
 166
 167 corrupt:
 168         ND_PRINT((ndo, ": %s", cstr));
 169         ND_TCHECK2(*cp, ep - cp);
 170         return 0;
 171 trunc:
 172         ND_PRINT((ndo, "%s", tstr));
 173         return -1;
 174 }
 175
 176 static int
 177 ahcp_ipv4_addresses_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
 178 {
 179         const char *sep = ": ";
 180
 181         while (cp < ep) {
 182                 if (cp + 4 > ep)
 183                         goto corrupt;
 184                 ND_TCHECK2(*cp, 4);
 185                 ND_PRINT((ndo, "%s%s", sep, ipaddr_string(ndo, cp)));
 186                 cp += 4;
 187                 sep = ", ";
 188         }
 189         return 0;
 190
 191 corrupt:
 192         ND_PRINT((ndo, ": %s", cstr));
 193         ND_TCHECK2(*cp, ep - cp);
 194         return 0;
 195 trunc:
 196         ND_PRINT((ndo, "%s", tstr));
 197         return -1;
 198 }
 199
 200 static int
 201 ahcp_ipv6_prefixes_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
 202 {
 203         const char *sep = ": ";
 204
 205         while (cp < ep) {
 206                 if (cp + 17 > ep)
 207                         goto corrupt;
 208                 ND_TCHECK2(*cp, 17);
 209 #ifdef INET6
 210                 ND_PRINT((ndo, "%s%s/%u", sep, ip6addr_string(ndo, cp), *(cp + 16)));
 211 #else
 212                 ND_PRINT((ndo, "%s(compiled w/o IPv6)/%u", sep, *(cp + 16)));
 213 #endif /* INET6 */
 214                 cp += 17;
 215                 sep = ", ";
 216         }
 217         return 0;
 218
 219 corrupt:
 220         ND_PRINT((ndo, ": %s", cstr));
 221         ND_TCHECK2(*cp, ep - cp);
 222         return 0;
 223 trunc:
 224         ND_PRINT((ndo, "%s", tstr));
 225         return -1;
 226 }
 227
 228 static int
 229 ahcp_ipv4_prefixes_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
 230 {
 231         const char *sep = ": ";
 232
 233         while (cp < ep) {
 234                 if (cp + 5 > ep)
 235                         goto corrupt;
 236                 ND_TCHECK2(*cp, 5);
 237                 ND_PRINT((ndo, "%s%s/%u", sep, ipaddr_string(ndo, cp), *(cp + 4)));
 238                 cp += 5;
 239                 sep = ", ";
 240         }
 241         return 0;
 242
 243 corrupt:
 244         ND_PRINT((ndo, ": %s", cstr));
 245         ND_TCHECK2(*cp, ep - cp);
 246         return 0;
 247 trunc:
 248         ND_PRINT((ndo, "%s", tstr));
 249         return -1;
 250 }
 251
 252 /* Data decoders signal truncated data with -1. */
 253 static int
 254 (* const data_decoders[AHCP1_OPT_MAX + 1])(netdissect_options *, const u_char *, const u_char *) = {
 255         /* [AHCP1_OPT_PAD]                    = */  NULL,
 256         /* [AHCP1_OPT_MANDATORY]              = */  NULL,
 257         /* [AHCP1_OPT_ORIGIN_TIME]            = */  ahcp_time_print,
 258         /* [AHCP1_OPT_EXPIRES]                = */  ahcp_seconds_print,
 259         /* [AHCP1_OPT_MY_IPV6_ADDRESS]        = */  ahcp_ipv6_addresses_print,
 260         /* [AHCP1_OPT_MY_IPV4_ADDRESS]        = */  ahcp_ipv4_addresses_print,
 261         /* [AHCP1_OPT_IPV6_PREFIX]            = */  ahcp_ipv6_prefixes_print,
 262         /* [AHCP1_OPT_IPV4_PREFIX]            = */  NULL,
 263         /* [AHCP1_OPT_IPV6_ADDRESS]           = */  ahcp_ipv6_addresses_print,
 264         /* [AHCP1_OPT_IPV4_ADDRESS]           = */  ahcp_ipv4_addresses_print,
 265         /* [AHCP1_OPT_IPV6_PREFIX_DELEGATION] = */  ahcp_ipv6_prefixes_print,
 266         /* [AHCP1_OPT_IPV4_PREFIX_DELEGATION] = */  ahcp_ipv4_prefixes_print,
 267         /* [AHCP1_OPT_NAME_SERVER]            = */  ahcp_ipv6_addresses_print,
 268         /* [AHCP1_OPT_NTP_SERVER]             = */  ahcp_ipv6_addresses_print,
 269 };
 270
 271 static void
 272 ahcp1_options_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
 273 {
 274         uint8_t option_no, option_len;
 275
 276         while (cp < ep) {
 277                 /* Option no */
 278                 ND_TCHECK2(*cp, 1);
 279                 option_no = *cp;
 280                 cp += 1;
 281                 ND_PRINT((ndo, "\n\t %s", tok2str(ahcp1_opt_str, "Unknown-%u", option_no)));
 282                 if (option_no == AHCP1_OPT_PAD || option_no == AHCP1_OPT_MANDATORY)
 283                         continue;
 284                 /* Length */
 285                 if (cp + 1 > ep)
 286                         goto corrupt;
 287                 ND_TCHECK2(*cp, 1);
 288                 option_len = *cp;
 289                 cp += 1;
 290                 if (cp + option_len > ep)
 291                         goto corrupt;
 292                 /* Value */
 293                 if (option_no <= AHCP1_OPT_MAX && data_decoders[option_no] != NULL) {
 294                         if (data_decoders[option_no](ndo, cp, cp + option_len) < 0)
 295                                 break; /* truncated and already marked up */
 296                 } else {
 297                         ND_PRINT((ndo, " (Length %u)", option_len));
 298                         ND_TCHECK2(*cp, option_len);
 299                 }
 300                 cp += option_len;
 301         }
 302         return;
 303
 304 corrupt:
 305         ND_PRINT((ndo, " %s", cstr));
 306         ND_TCHECK2(*cp, ep - cp);
 307         return;
 308 trunc:
 309         ND_PRINT((ndo, "%s", tstr));
 310 }
 311
 312 static void
 313 ahcp1_body_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
 314 {
 315         uint8_t type, mbz;
 316         uint16_t body_len;
 317
 318         if (cp + AHCP1_BODY_MIN_LEN > ep)
 319                 goto corrupt;
 320         /* Type */
 321         ND_TCHECK2(*cp, 1);
 322         type = *cp;
 323         cp += 1;
 324         /* MBZ */
 325         ND_TCHECK2(*cp, 1);
 326         mbz = *cp;
 327         cp += 1;
 328         /* Length */
 329         ND_TCHECK2(*cp, 2);
 330         body_len = EXTRACT_16BITS(cp);
 331         cp += 2;
 332
 333         if (ndo->ndo_vflag) {
 334                 ND_PRINT((ndo, "\n\t%s", tok2str(ahcp1_msg_str, "Unknown-%u", type)));
 335                 if (mbz != 0)
 336                         ND_PRINT((ndo, ", MBZ %u", mbz));
 337                 ND_PRINT((ndo, ", Length %u", body_len));
 338         }
 339         if (cp + body_len > ep)
 340                 goto corrupt;
 341
 342         /* Options */
 343         if (ndo->ndo_vflag >= 2)
 344                 ahcp1_options_print(ndo, cp, cp + body_len); /* not ep (ignore extra data) */
 345         else
 346                 ND_TCHECK2(*cp, body_len);
 347         return;
 348
 349 corrupt:
 350         ND_PRINT((ndo, " %s", cstr));
 351         ND_TCHECK2(*cp, ep - cp);
 352         return;
 353 trunc:
 354         ND_PRINT((ndo, "%s", tstr));
 355 }
 356
 357 void
 358 ahcp_print(netdissect_options *ndo, const u_char *cp, const u_int len)
 359 {
 360         const u_char *ep = cp + len;
 361         uint8_t version;
 362
 363         ND_PRINT((ndo, "AHCP"));
 364         if (len < 2)
 365                 goto corrupt;
 366         /* Magic */
 367         ND_TCHECK2(*cp, 1);
 368         if (*cp != AHCP_MAGIC_NUMBER)
 369                 goto corrupt;
 370         cp += 1;
 371         /* Version */
 372         ND_TCHECK2(*cp, 1);
 373         version = *cp;
 374         cp += 1;
 375         switch (version) {
 376                 case AHCP_VERSION_1: {
 377                         ND_PRINT((ndo, " Version 1"));
 378                         if (len < AHCP1_HEADER_FIX_LEN)
 379                                 goto corrupt;
 380                         if (!ndo->ndo_vflag) {
 381                                 ND_TCHECK2(*cp, AHCP1_HEADER_FIX_LEN - 2);
 382                                 cp += AHCP1_HEADER_FIX_LEN - 2;
 383                         } else {
 384                                 /* Hopcount */
 385                                 ND_TCHECK2(*cp, 1);
 386                                 ND_PRINT((ndo, "\n\tHopcount %u", *cp));
 387                                 cp += 1;
 388                                 /* Original Hopcount */
 389                                 ND_TCHECK2(*cp, 1);
 390                                 ND_PRINT((ndo, ", Original Hopcount %u", *cp));
 391                                 cp += 1;
 392                                 /* Nonce */
 393                                 ND_TCHECK2(*cp, 4);
 394                                 ND_PRINT((ndo, ", Nonce 0x%08x", EXTRACT_32BITS(cp)));
 395                                 cp += 4;
 396                                 /* Source Id */
 397                                 ND_TCHECK2(*cp, 8);
 398                                 ND_PRINT((ndo, ", Source Id %s", linkaddr_string(ndo, cp, 0, 8)));
 399                                 cp += 8;
 400                                 /* Destination Id */
 401                                 ND_TCHECK2(*cp, 8);
 402                                 ND_PRINT((ndo, ", Destination Id %s", linkaddr_string(ndo, cp, 0, 8)));
 403                                 cp += 8;
 404                         }
 405                         /* Body */
 406                         ahcp1_body_print(ndo, cp, ep);
 407                         break;
 408                 }
 409                 default:
 410                         ND_PRINT((ndo, " Version %u (unknown)", version));
 411                         break;
 412         }
 413         return;
 414
 415 corrupt:
 416         ND_PRINT((ndo, " %s", cstr));
 417         ND_TCHECK2(*cp, ep - cp);
 418         return;
 419 trunc:
 420         ND_PRINT((ndo, "%s", tstr));
 421 }