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 #include "netdissect.h"
  39 #include "extract.h"
  40 #include "addrtoname.h"
  41
  42
  43 #define AHCP_MAGIC_NUMBER 43
  44 #define AHCP_VERSION_1 1
  45 #define AHCP1_HEADER_FIX_LEN 24
  46 #define AHCP1_BODY_MIN_LEN 4
  47
  48 #define AHCP1_MSG_DISCOVER 0
  49 #define AHCP1_MSG_OFFER    1
  50 #define AHCP1_MSG_REQUEST  2
  51 #define AHCP1_MSG_ACK      3
  52 #define AHCP1_MSG_NACK     4
  53 #define AHCP1_MSG_RELEASE  5
  54
  55 static const struct tok ahcp1_msg_str[] = {
  56         { AHCP1_MSG_DISCOVER, "Discover" },
  57         { AHCP1_MSG_OFFER,    "Offer"    },
  58         { AHCP1_MSG_REQUEST,  "Request"  },
  59         { AHCP1_MSG_ACK,      "Ack"      },
  60         { AHCP1_MSG_NACK,     "Nack"     },
  61         { AHCP1_MSG_RELEASE,  "Release"  },
  62         { 0, NULL }
  63 };
  64
  65 #define AHCP1_OPT_PAD                     0
  66 #define AHCP1_OPT_MANDATORY               1
  67 #define AHCP1_OPT_ORIGIN_TIME             2
  68 #define AHCP1_OPT_EXPIRES                 3
  69 #define AHCP1_OPT_MY_IPV6_ADDRESS         4
  70 #define AHCP1_OPT_MY_IPV4_ADDRESS         5
  71 #define AHCP1_OPT_IPV6_PREFIX             6
  72 #define AHCP1_OPT_IPV4_PREFIX             7
  73 #define AHCP1_OPT_IPV6_ADDRESS            8
  74 #define AHCP1_OPT_IPV4_ADDRESS            9
  75 #define AHCP1_OPT_IPV6_PREFIX_DELEGATION 10
  76 #define AHCP1_OPT_IPV4_PREFIX_DELEGATION 11
  77 #define AHCP1_OPT_NAME_SERVER            12
  78 #define AHCP1_OPT_NTP_SERVER             13
  79 #define AHCP1_OPT_MAX                    13
  80
  81 static const struct tok ahcp1_opt_str[] = {
  82         { AHCP1_OPT_PAD,                    "Pad"                    },
  83         { AHCP1_OPT_MANDATORY,              "Mandatory"              },
  84         { AHCP1_OPT_ORIGIN_TIME,            "Origin Time"            },
  85         { AHCP1_OPT_EXPIRES,                "Expires"                },
  86         { AHCP1_OPT_MY_IPV6_ADDRESS,        "My-IPv6-Address"        },
  87         { AHCP1_OPT_MY_IPV4_ADDRESS,        "My-IPv4-Address"        },
  88         { AHCP1_OPT_IPV6_PREFIX,            "IPv6 Prefix"            },
  89         { AHCP1_OPT_IPV4_PREFIX,            "IPv4 Prefix"            },
  90         { AHCP1_OPT_IPV6_ADDRESS,           "IPv6 Address"           },
  91         { AHCP1_OPT_IPV4_ADDRESS,           "IPv4 Address"           },
  92         { AHCP1_OPT_IPV6_PREFIX_DELEGATION, "IPv6 Prefix Delegation" },
  93         { AHCP1_OPT_IPV4_PREFIX_DELEGATION, "IPv4 Prefix Delegation" },
  94         { AHCP1_OPT_NAME_SERVER,            "Name Server"            },
  95         { AHCP1_OPT_NTP_SERVER,             "NTP Server"             },
  96         { 0, NULL }
  97 };
  98
  99 static void
 100 ahcp_time_print(netdissect_options *ndo,
 101                 const u_char *cp, uint8_t len)
 102 {
 103         time_t t;
 104         struct tm *tm;
 105         char buf[BUFSIZE];
 106
 107         if (len != 4)
 108                 goto invalid;
 109         t = GET_BE_U_4(cp);
 110         if (NULL == (tm = gmtime(&t)))
 111                 ND_PRINT(": gmtime() error");
 112         else if (0 == strftime(buf, sizeof(buf), "%Y-%m-%d %H:%M:%S", tm))
 113                 ND_PRINT(": strftime() error");
 114         else
 115                 ND_PRINT(": %s UTC", buf);
 116         return;
 117
 118 invalid:
 119         nd_print_invalid(ndo);
 120         ND_TCHECK_LEN(cp, len);
 121         return;
 122 trunc:
 123         nd_trunc(ndo);
 124 }
 125
 126 static void
 127 ahcp_seconds_print(netdissect_options *ndo,
 128                    const u_char *cp, uint8_t len)
 129 {
 130         if (len != 4)
 131                 goto invalid;
 132         ND_PRINT(": %us", GET_BE_U_4(cp));
 133         return;
 134
 135 invalid:
 136         nd_print_invalid(ndo);
 137         ND_TCHECK_LEN(cp, len);
 138         return;
 139 trunc:
 140         nd_trunc(ndo);
 141 }
 142
 143 static void
 144 ahcp_ipv6_addresses_print(netdissect_options *ndo,
 145                           const u_char *cp, uint8_t len)
 146 {
 147         const char *sep = ": ";
 148
 149         while (len) {
 150                 if (len < 16)
 151                         goto invalid;
 152                 ND_PRINT("%s%s", sep, GET_IP6ADDR_STRING(cp));
 153                 cp += 16;
 154                 len -= 16;
 155                 sep = ", ";
 156         }
 157         return;
 158
 159 invalid:
 160         nd_print_invalid(ndo);
 161         ND_TCHECK_LEN(cp, len);
 162         return;
 163 trunc:
 164         nd_trunc(ndo);
 165 }
 166
 167 static void
 168 ahcp_ipv4_addresses_print(netdissect_options *ndo,
 169                           const u_char *cp, uint8_t len)
 170 {
 171         const char *sep = ": ";
 172
 173         while (len) {
 174                 if (len < 4)
 175                         goto invalid;
 176                 ND_PRINT("%s%s", sep, GET_IPADDR_STRING(cp));
 177                 cp += 4;
 178                 len -= 4;
 179                 sep = ", ";
 180         }
 181         return;
 182
 183 invalid:
 184         nd_print_invalid(ndo);
 185         ND_TCHECK_LEN(cp, len);
 186         return;
 187 trunc:
 188         nd_trunc(ndo);
 189 }
 190
 191 static void
 192 ahcp_ipv6_prefixes_print(netdissect_options *ndo,
 193                          const u_char *cp, uint8_t len)
 194 {
 195         const char *sep = ": ";
 196
 197         while (len) {
 198                 if (len < 17)
 199                         goto invalid;
 200                 ND_PRINT("%s%s/%u", sep, GET_IP6ADDR_STRING(cp), GET_U_1(cp + 16));
 201                 cp += 17;
 202                 len -= 17;
 203                 sep = ", ";
 204         }
 205         return;
 206
 207 invalid:
 208         nd_print_invalid(ndo);
 209         ND_TCHECK_LEN(cp, len);
 210         return;
 211 trunc:
 212         nd_trunc(ndo);
 213 }
 214
 215 static void
 216 ahcp_ipv4_prefixes_print(netdissect_options *ndo,
 217                          const u_char *cp, uint8_t len)
 218 {
 219         const char *sep = ": ";
 220
 221         while (len) {
 222                 if (len < 5)
 223                         goto invalid;
 224                 ND_PRINT("%s%s/%u", sep, GET_IPADDR_STRING(cp), GET_U_1(cp + 4));
 225                 cp += 5;
 226                 len -= 5;
 227                 sep = ", ";
 228         }
 229         return;
 230
 231 invalid:
 232         nd_print_invalid(ndo);
 233         ND_TCHECK_LEN(cp, len);
 234         return;
 235 trunc:
 236         nd_trunc(ndo);
 237 }
 238
 239 static void
 240 (* const data_decoders[AHCP1_OPT_MAX + 1])(netdissect_options *, const u_char *, uint8_t) = {
 241         /* [AHCP1_OPT_PAD]                    = */  NULL,
 242         /* [AHCP1_OPT_MANDATORY]              = */  NULL,
 243         /* [AHCP1_OPT_ORIGIN_TIME]            = */  ahcp_time_print,
 244         /* [AHCP1_OPT_EXPIRES]                = */  ahcp_seconds_print,
 245         /* [AHCP1_OPT_MY_IPV6_ADDRESS]        = */  ahcp_ipv6_addresses_print,
 246         /* [AHCP1_OPT_MY_IPV4_ADDRESS]        = */  ahcp_ipv4_addresses_print,
 247         /* [AHCP1_OPT_IPV6_PREFIX]            = */  ahcp_ipv6_prefixes_print,
 248         /* [AHCP1_OPT_IPV4_PREFIX]            = */  NULL,
 249         /* [AHCP1_OPT_IPV6_ADDRESS]           = */  ahcp_ipv6_addresses_print,
 250         /* [AHCP1_OPT_IPV4_ADDRESS]           = */  ahcp_ipv4_addresses_print,
 251         /* [AHCP1_OPT_IPV6_PREFIX_DELEGATION] = */  ahcp_ipv6_prefixes_print,
 252         /* [AHCP1_OPT_IPV4_PREFIX_DELEGATION] = */  ahcp_ipv4_prefixes_print,
 253         /* [AHCP1_OPT_NAME_SERVER]            = */  ahcp_ipv6_addresses_print,
 254         /* [AHCP1_OPT_NTP_SERVER]             = */  ahcp_ipv6_addresses_print,
 255 };
 256
 257 static void
 258 ahcp1_options_print(netdissect_options *ndo,
 259                     const u_char *cp, uint16_t len)
 260 {
 261         while (len) {
 262                 uint8_t option_no, option_len;
 263
 264                 /* Option no */
 265                 option_no = GET_U_1(cp);
 266                 cp += 1;
 267                 len -= 1;
 268                 ND_PRINT("\n\t %s", tok2str(ahcp1_opt_str, "Unknown-%u", option_no));
 269                 if (option_no == AHCP1_OPT_PAD || option_no == AHCP1_OPT_MANDATORY)
 270                         continue;
 271                 /* Length */
 272                 if (!len)
 273                         goto invalid;
 274                 option_len = GET_U_1(cp);
 275                 cp += 1;
 276                 len -= 1;
 277                 if (option_len > len)
 278                         goto invalid;
 279                 /* Value */
 280                 if (option_no <= AHCP1_OPT_MAX && data_decoders[option_no] != NULL) {
 281                         data_decoders[option_no](ndo, cp, option_len);
 282                 } else {
 283                         ND_PRINT(" (Length %u)", option_len);
 284                         ND_TCHECK_LEN(cp, option_len);
 285                 }
 286                 cp += option_len;
 287                 len -= option_len;
 288         }
 289         return;
 290
 291 invalid:
 292         nd_print_invalid(ndo);
 293         ND_TCHECK_LEN(cp, len);
 294         return;
 295 trunc:
 296         nd_trunc(ndo);
 297 }
 298
 299 static void
 300 ahcp1_body_print(netdissect_options *ndo,
 301                  const u_char *cp, u_int len)
 302 {
 303         uint8_t type, mbz;
 304         uint16_t body_len;
 305
 306         if (len < AHCP1_BODY_MIN_LEN)
 307                 goto invalid;
 308         /* Type */
 309         type = GET_U_1(cp);
 310         cp += 1;
 311         len -= 1;
 312         /* MBZ */
 313         mbz = GET_U_1(cp);
 314         cp += 1;
 315         len -= 1;
 316         /* Length */
 317         body_len = GET_BE_U_2(cp);
 318         cp += 2;
 319         len -= 2;
 320
 321         if (ndo->ndo_vflag) {
 322                 ND_PRINT("\n\t%s", tok2str(ahcp1_msg_str, "Unknown-%u", type));
 323                 if (mbz != 0)
 324                         ND_PRINT(", MBZ %u", mbz);
 325                 ND_PRINT(", Length %u", body_len);
 326         }
 327         if (body_len > len)
 328                 goto invalid;
 329
 330         /* Options */
 331         /* Here use "body_len", not "len" (ignore any extra data). */
 332         if (ndo->ndo_vflag >= 2)
 333                 ahcp1_options_print(ndo, cp, body_len);
 334         else
 335                 ND_TCHECK_LEN(cp, body_len);
 336         return;
 337
 338 invalid:
 339         nd_print_invalid(ndo);
 340         ND_TCHECK_LEN(cp, len);
 341         return;
 342 trunc:
 343         nd_trunc(ndo);
 344 }
 345
 346 void
 347 ahcp_print(netdissect_options *ndo,
 348            const u_char *cp, u_int len)
 349 {
 350         uint8_t version;
 351
 352         ndo->ndo_protocol = "ahcp";
 353         nd_print_protocol_caps(ndo);
 354         if (len < 2)
 355                 goto invalid;
 356         /* Magic */
 357         if (GET_U_1(cp) != AHCP_MAGIC_NUMBER)
 358                 goto invalid;
 359         cp += 1;
 360         len -= 1;
 361         /* Version */
 362         version = GET_U_1(cp);
 363         cp += 1;
 364         len -= 1;
 365         switch (version) {
 366                 case AHCP_VERSION_1: {
 367                         ND_PRINT(" Version 1");
 368                         if (len < AHCP1_HEADER_FIX_LEN - 2)
 369                                 goto invalid;
 370                         if (!ndo->ndo_vflag) {
 371                                 ND_TCHECK_LEN(cp, AHCP1_HEADER_FIX_LEN - 2);
 372                                 cp += AHCP1_HEADER_FIX_LEN - 2;
 373                                 len -= AHCP1_HEADER_FIX_LEN - 2;
 374                         } else {
 375                                 /* Hopcount */
 376                                 ND_PRINT("\n\tHopcount %u", GET_U_1(cp));
 377                                 cp += 1;
 378                                 len -= 1;
 379                                 /* Original Hopcount */
 380                                 ND_PRINT(", Original Hopcount %u", GET_U_1(cp));
 381                                 cp += 1;
 382                                 len -= 1;
 383                                 /* Nonce */
 384                                 ND_PRINT(", Nonce 0x%08x", GET_BE_U_4(cp));
 385                                 cp += 4;
 386                                 len -= 4;
 387                                 /* Source Id */
 388                                 ND_PRINT(", Source Id %s", GET_LINKADDR_STRING(cp, LINKADDR_OTHER, 8));
 389                                 cp += 8;
 390                                 len -= 8;
 391                                 /* Destination Id */
 392                                 ND_PRINT(", Destination Id %s", GET_LINKADDR_STRING(cp, LINKADDR_OTHER, 8));
 393                                 cp += 8;
 394                                 len -= 8;
 395                         }
 396                         /* Body */
 397                         ahcp1_body_print(ndo, cp, len);
 398                         break;
 399                 }
 400                 default:
 401                         ND_PRINT(" Version %u (unknown)", version);
 402                         ND_TCHECK_LEN(cp, len);
 403                         break;
 404         }
 405         return;
 406
 407 invalid:
 408         nd_print_invalid(ndo);
 409         ND_TCHECK_LEN(cp, len);
 410         return;
 411 trunc:
 412         nd_trunc(ndo);
 413 }