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         struct tm *tm;
 106         char buf[BUFSIZE];
 107
 108         if (len != 4)
 109                 goto invalid;
 110         t = GET_BE_U_4(cp);
 111         if (NULL == (tm = gmtime(&t)))
 112                 ND_PRINT(": gmtime() error");
 113         else if (0 == strftime(buf, sizeof(buf), "%Y-%m-%d %H:%M:%S", tm))
 114                 ND_PRINT(": strftime() error");
 115         else
 116                 ND_PRINT(": %s UTC", buf);
 117         return;
 118
 119 invalid:
 120         nd_print_invalid(ndo);
 121         ND_TCHECK_LEN(cp, len);
 122 }
 123
 124 static void
 125 ahcp_seconds_print(netdissect_options *ndo,
 126                    const u_char *cp, uint8_t len)
 127 {
 128         if (len != 4)
 129                 goto invalid;
 130         ND_PRINT(": %us", GET_BE_U_4(cp));
 131         return;
 132
 133 invalid:
 134         nd_print_invalid(ndo);
 135         ND_TCHECK_LEN(cp, len);
 136 }
 137
 138 static void
 139 ahcp_ipv6_addresses_print(netdissect_options *ndo,
 140                           const u_char *cp, uint8_t len)
 141 {
 142         const char *sep = ": ";
 143
 144         while (len) {
 145                 if (len < 16)
 146                         goto invalid;
 147                 ND_PRINT("%s%s", sep, GET_IP6ADDR_STRING(cp));
 148                 cp += 16;
 149                 len -= 16;
 150                 sep = ", ";
 151         }
 152         return;
 153
 154 invalid:
 155         nd_print_invalid(ndo);
 156         ND_TCHECK_LEN(cp, len);
 157 }
 158
 159 static void
 160 ahcp_ipv4_addresses_print(netdissect_options *ndo,
 161                           const u_char *cp, uint8_t len)
 162 {
 163         const char *sep = ": ";
 164
 165         while (len) {
 166                 if (len < 4)
 167                         goto invalid;
 168                 ND_PRINT("%s%s", sep, GET_IPADDR_STRING(cp));
 169                 cp += 4;
 170                 len -= 4;
 171                 sep = ", ";
 172         }
 173         return;
 174
 175 invalid:
 176         nd_print_invalid(ndo);
 177         ND_TCHECK_LEN(cp, len);
 178 }
 179
 180 static void
 181 ahcp_ipv6_prefixes_print(netdissect_options *ndo,
 182                          const u_char *cp, uint8_t len)
 183 {
 184         const char *sep = ": ";
 185
 186         while (len) {
 187                 if (len < 17)
 188                         goto invalid;
 189                 ND_PRINT("%s%s/%u", sep, GET_IP6ADDR_STRING(cp), GET_U_1(cp + 16));
 190                 cp += 17;
 191                 len -= 17;
 192                 sep = ", ";
 193         }
 194         return;
 195
 196 invalid:
 197         nd_print_invalid(ndo);
 198         ND_TCHECK_LEN(cp, len);
 199 }
 200
 201 static void
 202 ahcp_ipv4_prefixes_print(netdissect_options *ndo,
 203                          const u_char *cp, uint8_t len)
 204 {
 205         const char *sep = ": ";
 206
 207         while (len) {
 208                 if (len < 5)
 209                         goto invalid;
 210                 ND_PRINT("%s%s/%u", sep, GET_IPADDR_STRING(cp), GET_U_1(cp + 4));
 211                 cp += 5;
 212                 len -= 5;
 213                 sep = ", ";
 214         }
 215         return;
 216
 217 invalid:
 218         nd_print_invalid(ndo);
 219         ND_TCHECK_LEN(cp, len);
 220 }
 221
 222 static void
 223 (* const data_decoders[AHCP1_OPT_MAX + 1])(netdissect_options *, const u_char *, uint8_t) = {
 224         /* [AHCP1_OPT_PAD]                    = */  NULL,
 225         /* [AHCP1_OPT_MANDATORY]              = */  NULL,
 226         /* [AHCP1_OPT_ORIGIN_TIME]            = */  ahcp_time_print,
 227         /* [AHCP1_OPT_EXPIRES]                = */  ahcp_seconds_print,
 228         /* [AHCP1_OPT_MY_IPV6_ADDRESS]        = */  ahcp_ipv6_addresses_print,
 229         /* [AHCP1_OPT_MY_IPV4_ADDRESS]        = */  ahcp_ipv4_addresses_print,
 230         /* [AHCP1_OPT_IPV6_PREFIX]            = */  ahcp_ipv6_prefixes_print,
 231         /* [AHCP1_OPT_IPV4_PREFIX]            = */  NULL,
 232         /* [AHCP1_OPT_IPV6_ADDRESS]           = */  ahcp_ipv6_addresses_print,
 233         /* [AHCP1_OPT_IPV4_ADDRESS]           = */  ahcp_ipv4_addresses_print,
 234         /* [AHCP1_OPT_IPV6_PREFIX_DELEGATION] = */  ahcp_ipv6_prefixes_print,
 235         /* [AHCP1_OPT_IPV4_PREFIX_DELEGATION] = */  ahcp_ipv4_prefixes_print,
 236         /* [AHCP1_OPT_NAME_SERVER]            = */  ahcp_ipv6_addresses_print,
 237         /* [AHCP1_OPT_NTP_SERVER]             = */  ahcp_ipv6_addresses_print,
 238 };
 239
 240 static void
 241 ahcp1_options_print(netdissect_options *ndo,
 242                     const u_char *cp, uint16_t len)
 243 {
 244         while (len) {
 245                 uint8_t option_no, option_len;
 246
 247                 /* Option no */
 248                 option_no = GET_U_1(cp);
 249                 cp += 1;
 250                 len -= 1;
 251                 ND_PRINT("\n\t %s", tok2str(ahcp1_opt_str, "Unknown-%u", option_no));
 252                 if (option_no == AHCP1_OPT_PAD || option_no == AHCP1_OPT_MANDATORY)
 253                         continue;
 254                 /* Length */
 255                 if (!len)
 256                         goto invalid;
 257                 option_len = GET_U_1(cp);
 258                 cp += 1;
 259                 len -= 1;
 260                 if (option_len > len)
 261                         goto invalid;
 262                 /* Value */
 263                 if (option_no <= AHCP1_OPT_MAX && data_decoders[option_no] != NULL) {
 264                         data_decoders[option_no](ndo, cp, option_len);
 265                 } else {
 266                         ND_PRINT(" (Length %u)", option_len);
 267                         ND_TCHECK_LEN(cp, option_len);
 268                 }
 269                 cp += option_len;
 270                 len -= option_len;
 271         }
 272         return;
 273
 274 invalid:
 275         nd_print_invalid(ndo);
 276         ND_TCHECK_LEN(cp, len);
 277 }
 278
 279 static void
 280 ahcp1_body_print(netdissect_options *ndo,
 281                  const u_char *cp, u_int len)
 282 {
 283         uint8_t type, mbz;
 284         uint16_t body_len;
 285
 286         if (len < AHCP1_BODY_MIN_LEN)
 287                 goto invalid;
 288         /* Type */
 289         type = GET_U_1(cp);
 290         cp += 1;
 291         len -= 1;
 292         /* MBZ */
 293         mbz = GET_U_1(cp);
 294         cp += 1;
 295         len -= 1;
 296         /* Length */
 297         body_len = GET_BE_U_2(cp);
 298         cp += 2;
 299         len -= 2;
 300
 301         if (ndo->ndo_vflag) {
 302                 ND_PRINT("\n\t%s", tok2str(ahcp1_msg_str, "Unknown-%u", type));
 303                 if (mbz != 0)
 304                         ND_PRINT(", MBZ %u", mbz);
 305                 ND_PRINT(", Length %u", body_len);
 306         }
 307         if (body_len > len)
 308                 goto invalid;
 309
 310         /* Options */
 311         /* Here use "body_len", not "len" (ignore any extra data). */
 312         if (ndo->ndo_vflag >= 2)
 313                 ahcp1_options_print(ndo, cp, body_len);
 314         else
 315                 ND_TCHECK_LEN(cp, body_len);
 316         return;
 317
 318 invalid:
 319         nd_print_invalid(ndo);
 320         ND_TCHECK_LEN(cp, len);
 321
 322 }
 323
 324 void
 325 ahcp_print(netdissect_options *ndo,
 326            const u_char *cp, u_int len)
 327 {
 328         uint8_t version;
 329
 330         ndo->ndo_protocol = "ahcp";
 331         nd_print_protocol_caps(ndo);
 332         if (len < 2)
 333                 goto invalid;
 334         /* Magic */
 335         if (GET_U_1(cp) != AHCP_MAGIC_NUMBER)
 336                 goto invalid;
 337         cp += 1;
 338         len -= 1;
 339         /* Version */
 340         version = GET_U_1(cp);
 341         cp += 1;
 342         len -= 1;
 343         switch (version) {
 344                 case AHCP_VERSION_1: {
 345                         ND_PRINT(" Version 1");
 346                         if (len < AHCP1_HEADER_FIX_LEN - 2)
 347                                 goto invalid;
 348                         if (!ndo->ndo_vflag) {
 349                                 ND_TCHECK_LEN(cp, AHCP1_HEADER_FIX_LEN - 2);
 350                                 cp += AHCP1_HEADER_FIX_LEN - 2;
 351                                 len -= AHCP1_HEADER_FIX_LEN - 2;
 352                         } else {
 353                                 /* Hopcount */
 354                                 ND_PRINT("\n\tHopcount %u", GET_U_1(cp));
 355                                 cp += 1;
 356                                 len -= 1;
 357                                 /* Original Hopcount */
 358                                 ND_PRINT(", Original Hopcount %u", GET_U_1(cp));
 359                                 cp += 1;
 360                                 len -= 1;
 361                                 /* Nonce */
 362                                 ND_PRINT(", Nonce 0x%08x", GET_BE_U_4(cp));
 363                                 cp += 4;
 364                                 len -= 4;
 365                                 /* Source Id */
 366                                 ND_PRINT(", Source Id %s", GET_LINKADDR_STRING(cp, LINKADDR_OTHER, 8));
 367                                 cp += 8;
 368                                 len -= 8;
 369                                 /* Destination Id */
 370                                 ND_PRINT(", Destination Id %s", GET_LINKADDR_STRING(cp, LINKADDR_OTHER, 8));
 371                                 cp += 8;
 372                                 len -= 8;
 373                         }
 374                         /* Body */
 375                         ahcp1_body_print(ndo, cp, len);
 376                         break;
 377                 }
 378                 default:
 379                         ND_PRINT(" Version %u (unknown)", version);
 380                         ND_TCHECK_LEN(cp, len);
 381                         break;
 382         }
 383         return;
 384
 385 invalid:
 386         nd_print_invalid(ndo);
 387         ND_TCHECK_LEN(cp, len);
 388 }