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 int
 100 ahcp_time_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
 101 {
 102         time_t t;
 103         struct tm *tm;
 104         char buf[BUFSIZE];
 105
 106         if (cp + 4 != ep)
 107                 goto invalid;
 108         ND_TCHECK_4(cp);
 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 0;
 117
 118 invalid:
 119         nd_print_invalid(ndo);
 120         ND_TCHECK_LEN(cp, ep - cp);
 121         return 0;
 122 trunc:
 123         nd_print_trunc(ndo);
 124         return -1;
 125 }
 126
 127 static int
 128 ahcp_seconds_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
 129 {
 130         if (cp + 4 != ep)
 131                 goto invalid;
 132         ND_TCHECK_4(cp);
 133         ND_PRINT(": %us", GET_BE_U_4(cp));
 134         return 0;
 135
 136 invalid:
 137         nd_print_invalid(ndo);
 138         ND_TCHECK_LEN(cp, ep - cp);
 139         return 0;
 140 trunc:
 141         nd_print_trunc(ndo);
 142         return -1;
 143 }
 144
 145 static int
 146 ahcp_ipv6_addresses_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
 147 {
 148         const char *sep = ": ";
 149
 150         while (cp < ep) {
 151                 if (cp + 16 > ep)
 152                         goto invalid;
 153                 ND_TCHECK_16(cp);
 154                 ND_PRINT("%s%s", sep, ip6addr_string(ndo, cp));
 155                 cp += 16;
 156                 sep = ", ";
 157         }
 158         return 0;
 159
 160 invalid:
 161         nd_print_invalid(ndo);
 162         ND_TCHECK_LEN(cp, ep - cp);
 163         return 0;
 164 trunc:
 165         nd_print_trunc(ndo);
 166         return -1;
 167 }
 168
 169 static int
 170 ahcp_ipv4_addresses_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
 171 {
 172         const char *sep = ": ";
 173
 174         while (cp < ep) {
 175                 if (cp + 4 > ep)
 176                         goto invalid;
 177                 ND_TCHECK_4(cp);
 178                 ND_PRINT("%s%s", sep, ipaddr_string(ndo, cp));
 179                 cp += 4;
 180                 sep = ", ";
 181         }
 182         return 0;
 183
 184 invalid:
 185         nd_print_invalid(ndo);
 186         ND_TCHECK_LEN(cp, ep - cp);
 187         return 0;
 188 trunc:
 189         nd_print_trunc(ndo);
 190         return -1;
 191 }
 192
 193 static int
 194 ahcp_ipv6_prefixes_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
 195 {
 196         const char *sep = ": ";
 197
 198         while (cp < ep) {
 199                 if (cp + 17 > ep)
 200                         goto invalid;
 201                 ND_TCHECK_LEN(cp, 17);
 202                 ND_PRINT("%s%s/%u", sep, ip6addr_string(ndo, cp),
 203                          GET_U_1(cp + 16));
 204                 cp += 17;
 205                 sep = ", ";
 206         }
 207         return 0;
 208
 209 invalid:
 210         nd_print_invalid(ndo);
 211         ND_TCHECK_LEN(cp, ep - cp);
 212         return 0;
 213 trunc:
 214         nd_print_trunc(ndo);
 215         return -1;
 216 }
 217
 218 static int
 219 ahcp_ipv4_prefixes_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
 220 {
 221         const char *sep = ": ";
 222
 223         while (cp < ep) {
 224                 if (cp + 5 > ep)
 225                         goto invalid;
 226                 ND_TCHECK_5(cp);
 227                 ND_PRINT("%s%s/%u", sep, ipaddr_string(ndo, cp),
 228                          GET_U_1(cp + 4));
 229                 cp += 5;
 230                 sep = ", ";
 231         }
 232         return 0;
 233
 234 invalid:
 235         nd_print_invalid(ndo);
 236         ND_TCHECK_LEN(cp, ep - cp);
 237         return 0;
 238 trunc:
 239         nd_print_trunc(ndo);
 240         return -1;
 241 }
 242
 243 /* Data decoders signal truncated data with -1. */
 244 static int
 245 (* const data_decoders[AHCP1_OPT_MAX + 1])(netdissect_options *, const u_char *, const u_char *) = {
 246         /* [AHCP1_OPT_PAD]                    = */  NULL,
 247         /* [AHCP1_OPT_MANDATORY]              = */  NULL,
 248         /* [AHCP1_OPT_ORIGIN_TIME]            = */  ahcp_time_print,
 249         /* [AHCP1_OPT_EXPIRES]                = */  ahcp_seconds_print,
 250         /* [AHCP1_OPT_MY_IPV6_ADDRESS]        = */  ahcp_ipv6_addresses_print,
 251         /* [AHCP1_OPT_MY_IPV4_ADDRESS]        = */  ahcp_ipv4_addresses_print,
 252         /* [AHCP1_OPT_IPV6_PREFIX]            = */  ahcp_ipv6_prefixes_print,
 253         /* [AHCP1_OPT_IPV4_PREFIX]            = */  NULL,
 254         /* [AHCP1_OPT_IPV6_ADDRESS]           = */  ahcp_ipv6_addresses_print,
 255         /* [AHCP1_OPT_IPV4_ADDRESS]           = */  ahcp_ipv4_addresses_print,
 256         /* [AHCP1_OPT_IPV6_PREFIX_DELEGATION] = */  ahcp_ipv6_prefixes_print,
 257         /* [AHCP1_OPT_IPV4_PREFIX_DELEGATION] = */  ahcp_ipv4_prefixes_print,
 258         /* [AHCP1_OPT_NAME_SERVER]            = */  ahcp_ipv6_addresses_print,
 259         /* [AHCP1_OPT_NTP_SERVER]             = */  ahcp_ipv6_addresses_print,
 260 };
 261
 262 static void
 263 ahcp1_options_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
 264 {
 265         uint8_t option_no, option_len;
 266
 267         while (cp < ep) {
 268                 /* Option no */
 269                 ND_TCHECK_1(cp);
 270                 option_no = GET_U_1(cp);
 271                 cp += 1;
 272                 ND_PRINT("\n\t %s", tok2str(ahcp1_opt_str, "Unknown-%u", option_no));
 273                 if (option_no == AHCP1_OPT_PAD || option_no == AHCP1_OPT_MANDATORY)
 274                         continue;
 275                 /* Length */
 276                 if (cp + 1 > ep)
 277                         goto invalid;
 278                 ND_TCHECK_1(cp);
 279                 option_len = GET_U_1(cp);
 280                 cp += 1;
 281                 if (cp + option_len > ep)
 282                         goto invalid;
 283                 /* Value */
 284                 if (option_no <= AHCP1_OPT_MAX && data_decoders[option_no] != NULL) {
 285                         if (data_decoders[option_no](ndo, cp, cp + option_len) < 0)
 286                                 break; /* truncated and already marked up */
 287                 } else {
 288                         ND_PRINT(" (Length %u)", option_len);
 289                         ND_TCHECK_LEN(cp, option_len);
 290                 }
 291                 cp += option_len;
 292         }
 293         return;
 294
 295 invalid:
 296         nd_print_invalid(ndo);
 297         ND_TCHECK_LEN(cp, ep - cp);
 298         return;
 299 trunc:
 300         nd_print_trunc(ndo);
 301 }
 302
 303 static void
 304 ahcp1_body_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
 305 {
 306         uint8_t type, mbz;
 307         uint16_t body_len;
 308
 309         if (cp + AHCP1_BODY_MIN_LEN > ep)
 310                 goto invalid;
 311         /* Type */
 312         ND_TCHECK_1(cp);
 313         type = GET_U_1(cp);
 314         cp += 1;
 315         /* MBZ */
 316         ND_TCHECK_1(cp);
 317         mbz = GET_U_1(cp);
 318         cp += 1;
 319         /* Length */
 320         ND_TCHECK_2(cp);
 321         body_len = GET_BE_U_2(cp);
 322         cp += 2;
 323
 324         if (ndo->ndo_vflag) {
 325                 ND_PRINT("\n\t%s", tok2str(ahcp1_msg_str, "Unknown-%u", type));
 326                 if (mbz != 0)
 327                         ND_PRINT(", MBZ %u", mbz);
 328                 ND_PRINT(", Length %u", body_len);
 329         }
 330         if (cp + body_len > ep)
 331                 goto invalid;
 332
 333         /* Options */
 334         if (ndo->ndo_vflag >= 2)
 335                 ahcp1_options_print(ndo, cp, cp + body_len); /* not ep (ignore extra data) */
 336         else
 337                 ND_TCHECK_LEN(cp, body_len);
 338         return;
 339
 340 invalid:
 341         nd_print_invalid(ndo);
 342         ND_TCHECK_LEN(cp, ep - cp);
 343         return;
 344 trunc:
 345         nd_print_trunc(ndo);
 346 }
 347
 348 void
 349 ahcp_print(netdissect_options *ndo, const u_char *cp, const u_int len)
 350 {
 351         const u_char *ep = ndo->ndo_snapend;
 352         uint8_t version;
 353
 354         ndo->ndo_protocol = "ahcp";
 355         nd_print_protocol_caps(ndo);
 356         if (len < 2)
 357                 goto invalid;
 358         /* Magic */
 359         ND_TCHECK_1(cp);
 360         if (GET_U_1(cp) != AHCP_MAGIC_NUMBER)
 361                 goto invalid;
 362         cp += 1;
 363         /* Version */
 364         ND_TCHECK_1(cp);
 365         version = GET_U_1(cp);
 366         cp += 1;
 367         switch (version) {
 368                 case AHCP_VERSION_1: {
 369                         ND_PRINT(" Version 1");
 370                         if (len < AHCP1_HEADER_FIX_LEN)
 371                                 goto invalid;
 372                         if (!ndo->ndo_vflag) {
 373                                 ND_TCHECK_LEN(cp, AHCP1_HEADER_FIX_LEN - 2);
 374                                 cp += AHCP1_HEADER_FIX_LEN - 2;
 375                         } else {
 376                                 /* Hopcount */
 377                                 ND_TCHECK_1(cp);
 378                                 ND_PRINT("\n\tHopcount %u", GET_U_1(cp));
 379                                 cp += 1;
 380                                 /* Original Hopcount */
 381                                 ND_TCHECK_1(cp);
 382                                 ND_PRINT(", Original Hopcount %u",
 383                                          GET_U_1(cp));
 384                                 cp += 1;
 385                                 /* Nonce */
 386                                 ND_TCHECK_4(cp);
 387                                 ND_PRINT(", Nonce 0x%08x", GET_BE_U_4(cp));
 388                                 cp += 4;
 389                                 /* Source Id */
 390                                 ND_TCHECK_8(cp);
 391                                 ND_PRINT(", Source Id %s", linkaddr_string(ndo, cp, LINKADDR_OTHER, 8));
 392                                 cp += 8;
 393                                 /* Destination Id */
 394                                 ND_TCHECK_8(cp);
 395                                 ND_PRINT(", Destination Id %s", linkaddr_string(ndo, cp, LINKADDR_OTHER, 8));
 396                                 cp += 8;
 397                         }
 398                         /* Body */
 399                         ahcp1_body_print(ndo, cp, ep);
 400                         break;
 401                 }
 402                 default:
 403                         ND_PRINT(" Version %u (unknown)", version);
 404                         break;
 405         }
 406         return;
 407
 408 invalid:
 409         nd_print_invalid(ndo);
 410         ND_TCHECK_LEN(cp, ep - cp);
 411         return;
 412 trunc:
 413         nd_print_trunc(ndo);
 414 }