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 #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
  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
 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
 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
 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
 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
 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
 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
 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
 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 }