The Tcpdump Group git mirrors - tcpdump/blob - print-ahcp.c

   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 #define ND_LONGJMP_FROM_TCHECK
  39 #include "netdissect.h"
  40 #include "extract.h"
  41 #include "addrtoname.h"
  42
  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 void
 101 ahcp_time_print(netdissect_options *ndo,
 102                 const u_char *cp, uint8_t len)
 103 {
 104         time_t t;
 105         char buf[sizeof("-yyyyyyyyyy-mm-dd hh:mm:ss UTC")];
 106
 107         if (len != 4)
 108                 goto invalid;
 109         t = GET_BE_U_4(cp);
 110         ND_PRINT(": %s",
 111             nd_format_time(buf, sizeof(buf), "%Y-%m-%d %H:%M:%S UTC",
 112               gmtime(&t)));
 113         return;
 114
 115 invalid:
 116         nd_print_invalid(ndo);
 117         ND_TCHECK_LEN(cp, len);
 118 }
 119
 120 static void
 121 ahcp_seconds_print(netdissect_options *ndo,
 122                    const u_char *cp, uint8_t len)
 123 {
 124         if (len != 4)
 125                 goto invalid;
 126         ND_PRINT(": %us", GET_BE_U_4(cp));
 127         return;
 128
 129 invalid:
 130         nd_print_invalid(ndo);
 131         ND_TCHECK_LEN(cp, len);
 132 }
 133
 134 static void
 135 ahcp_ipv6_addresses_print(netdissect_options *ndo,
 136                           const u_char *cp, uint8_t len)
 137 {
 138         const char *sep = ": ";
 139
 140         while (len) {
 141                 if (len < 16)
 142                         goto invalid;
 143                 ND_PRINT("%s%s", sep, GET_IP6ADDR_STRING(cp));
 144                 cp += 16;
 145                 len -= 16;
 146                 sep = ", ";
 147         }
 148         return;
 149
 150 invalid:
 151         nd_print_invalid(ndo);
 152         ND_TCHECK_LEN(cp, len);
 153 }
 154
 155 static void
 156 ahcp_ipv4_addresses_print(netdissect_options *ndo,
 157                           const u_char *cp, uint8_t len)
 158 {
 159         const char *sep = ": ";
 160
 161         while (len) {
 162                 if (len < 4)
 163                         goto invalid;
 164                 ND_PRINT("%s%s", sep, GET_IPADDR_STRING(cp));
 165                 cp += 4;
 166                 len -= 4;
 167                 sep = ", ";
 168         }
 169         return;
 170
 171 invalid:
 172         nd_print_invalid(ndo);
 173         ND_TCHECK_LEN(cp, len);
 174 }
 175
 176 static void
 177 ahcp_ipv6_prefixes_print(netdissect_options *ndo,
 178                          const u_char *cp, uint8_t len)
 179 {
 180         const char *sep = ": ";
 181
 182         while (len) {
 183                 if (len < 17)
 184                         goto invalid;
 185                 ND_PRINT("%s%s/%u", sep, GET_IP6ADDR_STRING(cp), GET_U_1(cp + 16));
 186                 cp += 17;
 187                 len -= 17;
 188                 sep = ", ";
 189         }
 190         return;
 191
 192 invalid:
 193         nd_print_invalid(ndo);
 194         ND_TCHECK_LEN(cp, len);
 195 }
 196
 197 static void
 198 ahcp_ipv4_prefixes_print(netdissect_options *ndo,
 199                          const u_char *cp, uint8_t len)
 200 {
 201         const char *sep = ": ";
 202
 203         while (len) {
 204                 if (len < 5)
 205                         goto invalid;
 206                 ND_PRINT("%s%s/%u", sep, GET_IPADDR_STRING(cp), GET_U_1(cp + 4));
 207                 cp += 5;
 208                 len -= 5;
 209                 sep = ", ";
 210         }
 211         return;
 212
 213 invalid:
 214         nd_print_invalid(ndo);
 215         ND_TCHECK_LEN(cp, len);
 216 }
 217
 218 static void
 219 (* const data_decoders[AHCP1_OPT_MAX + 1])(netdissect_options *, const u_char *, uint8_t) = {
 220         /* [AHCP1_OPT_PAD]                    = */  NULL,
 221         /* [AHCP1_OPT_MANDATORY]              = */  NULL,
 222         /* [AHCP1_OPT_ORIGIN_TIME]            = */  ahcp_time_print,
 223         /* [AHCP1_OPT_EXPIRES]                = */  ahcp_seconds_print,
 224         /* [AHCP1_OPT_MY_IPV6_ADDRESS]        = */  ahcp_ipv6_addresses_print,
 225         /* [AHCP1_OPT_MY_IPV4_ADDRESS]        = */  ahcp_ipv4_addresses_print,
 226         /* [AHCP1_OPT_IPV6_PREFIX]            = */  ahcp_ipv6_prefixes_print,
 227         /* [AHCP1_OPT_IPV4_PREFIX]            = */  NULL,
 228         /* [AHCP1_OPT_IPV6_ADDRESS]           = */  ahcp_ipv6_addresses_print,
 229         /* [AHCP1_OPT_IPV4_ADDRESS]           = */  ahcp_ipv4_addresses_print,
 230         /* [AHCP1_OPT_IPV6_PREFIX_DELEGATION] = */  ahcp_ipv6_prefixes_print,
 231         /* [AHCP1_OPT_IPV4_PREFIX_DELEGATION] = */  ahcp_ipv4_prefixes_print,
 232         /* [AHCP1_OPT_NAME_SERVER]            = */  ahcp_ipv6_addresses_print,
 233         /* [AHCP1_OPT_NTP_SERVER]             = */  ahcp_ipv6_addresses_print,
 234 };
 235
 236 static void
 237 ahcp1_options_print(netdissect_options *ndo,
 238                     const u_char *cp, uint16_t len)
 239 {
 240         while (len) {
 241                 uint8_t option_no, option_len;
 242
 243                 /* Option no */
 244                 option_no = GET_U_1(cp);
 245                 cp += 1;
 246                 len -= 1;
 247                 ND_PRINT("\n\t %s", tok2str(ahcp1_opt_str, "Unknown-%u", option_no));
 248                 if (option_no == AHCP1_OPT_PAD || option_no == AHCP1_OPT_MANDATORY)
 249                         continue;
 250                 /* Length */
 251                 if (!len)
 252                         goto invalid;
 253                 option_len = GET_U_1(cp);
 254                 cp += 1;
 255                 len -= 1;
 256                 if (option_len > len)
 257                         goto invalid;
 258                 /* Value */
 259                 if (option_no <= AHCP1_OPT_MAX && data_decoders[option_no] != NULL) {
 260                         data_decoders[option_no](ndo, cp, option_len);
 261                 } else {
 262                         ND_PRINT(" (Length %u)", option_len);
 263                         ND_TCHECK_LEN(cp, option_len);
 264                 }
 265                 cp += option_len;
 266                 len -= option_len;
 267         }
 268         return;
 269
 270 invalid:
 271         nd_print_invalid(ndo);
 272         ND_TCHECK_LEN(cp, len);
 273 }
 274
 275 static void
 276 ahcp1_body_print(netdissect_options *ndo,
 277                  const u_char *cp, u_int len)
 278 {
 279         uint8_t type, mbz;
 280         uint16_t body_len;
 281
 282         if (len < AHCP1_BODY_MIN_LEN)
 283                 goto invalid;
 284         /* Type */
 285         type = GET_U_1(cp);
 286         cp += 1;
 287         len -= 1;
 288         /* MBZ */
 289         mbz = GET_U_1(cp);
 290         cp += 1;
 291         len -= 1;
 292         /* Length */
 293         body_len = GET_BE_U_2(cp);
 294         cp += 2;
 295         len -= 2;
 296
 297         if (ndo->ndo_vflag) {
 298                 ND_PRINT("\n\t%s", tok2str(ahcp1_msg_str, "Unknown-%u", type));
 299                 if (mbz != 0)
 300                         ND_PRINT(", MBZ %u", mbz);
 301                 ND_PRINT(", Length %u", body_len);
 302         }
 303         if (body_len > len)
 304                 goto invalid;
 305
 306         /* Options */
 307         /* Here use "body_len", not "len" (ignore any extra data). */
 308         if (ndo->ndo_vflag >= 2)
 309                 ahcp1_options_print(ndo, cp, body_len);
 310         else
 311                 ND_TCHECK_LEN(cp, body_len);
 312         return;
 313
 314 invalid:
 315         nd_print_invalid(ndo);
 316         ND_TCHECK_LEN(cp, len);
 317
 318 }
 319
 320 void
 321 ahcp_print(netdissect_options *ndo,
 322            const u_char *cp, u_int len)
 323 {
 324         uint8_t version;
 325
 326         ndo->ndo_protocol = "ahcp";
 327         nd_print_protocol_caps(ndo);
 328         if (len < 2)
 329                 goto invalid;
 330         /* Magic */
 331         if (GET_U_1(cp) != AHCP_MAGIC_NUMBER)
 332                 goto invalid;
 333         cp += 1;
 334         len -= 1;
 335         /* Version */
 336         version = GET_U_1(cp);
 337         cp += 1;
 338         len -= 1;
 339         switch (version) {
 340                 case AHCP_VERSION_1: {
 341                         ND_PRINT(" Version 1");
 342                         if (len < AHCP1_HEADER_FIX_LEN - 2)
 343                                 goto invalid;
 344                         if (!ndo->ndo_vflag) {
 345                                 ND_TCHECK_LEN(cp, AHCP1_HEADER_FIX_LEN - 2);
 346                                 cp += AHCP1_HEADER_FIX_LEN - 2;
 347                                 len -= AHCP1_HEADER_FIX_LEN - 2;
 348                         } else {
 349                                 /* Hopcount */
 350                                 ND_PRINT("\n\tHopcount %u", GET_U_1(cp));
 351                                 cp += 1;
 352                                 len -= 1;
 353                                 /* Original Hopcount */
 354                                 ND_PRINT(", Original Hopcount %u", GET_U_1(cp));
 355                                 cp += 1;
 356                                 len -= 1;
 357                                 /* Nonce */
 358                                 ND_PRINT(", Nonce 0x%08x", GET_BE_U_4(cp));
 359                                 cp += 4;
 360                                 len -= 4;
 361                                 /* Source Id */
 362                                 ND_PRINT(", Source Id %s", GET_LINKADDR_STRING(cp, LINKADDR_OTHER, 8));
 363                                 cp += 8;
 364                                 len -= 8;
 365                                 /* Destination Id */
 366                                 ND_PRINT(", Destination Id %s", GET_LINKADDR_STRING(cp, LINKADDR_OTHER, 8));
 367                                 cp += 8;
 368                                 len -= 8;
 369                         }
 370                         /* Body */
 371                         ahcp1_body_print(ndo, cp, len);
 372                         break;
 373                 }
 374                 default:
 375                         ND_PRINT(" Version %u (unknown)", version);
 376                         ND_TCHECK_LEN(cp, len);
 377                         break;
 378         }
 379         return;
 380
 381 invalid:
 382         nd_print_invalid(ndo);
 383         ND_TCHECK_LEN(cp, len);
 384 }