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         t = GET_BE_U_4(cp);
 109         if (NULL == (tm = gmtime(&t)))
 110                 ND_PRINT(": gmtime() error");
 111         else if (0 == strftime(buf, sizeof(buf), "%Y-%m-%d %H:%M:%S", tm))
 112                 ND_PRINT(": strftime() error");
 113         else
 114                 ND_PRINT(": %s UTC", buf);
 115         return 0;
 116
 117 invalid:
 118         nd_print_invalid(ndo);
 119         ND_TCHECK_LEN(cp, ep - cp);
 120         return 0;
 121 trunc:
 122         nd_print_trunc(ndo);
 123         return -1;
 124 }
 125
 126 static int
 127 ahcp_seconds_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
 128 {
 129         if (cp + 4 != ep)
 130                 goto invalid;
 131         ND_PRINT(": %us", GET_BE_U_4(cp));
 132         return 0;
 133
 134 invalid:
 135         nd_print_invalid(ndo);
 136         ND_TCHECK_LEN(cp, ep - cp);
 137         return 0;
 138 trunc:
 139         nd_print_trunc(ndo);
 140         return -1;
 141 }
 142
 143 static int
 144 ahcp_ipv6_addresses_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
 145 {
 146         const char *sep = ": ";
 147
 148         while (cp < ep) {
 149                 if (cp + 16 > ep)
 150                         goto invalid;
 151                 ND_PRINT("%s%s", sep, GET_IP6ADDR_STRING(cp));
 152                 cp += 16;
 153                 sep = ", ";
 154         }
 155         return 0;
 156
 157 invalid:
 158         nd_print_invalid(ndo);
 159         ND_TCHECK_LEN(cp, ep - cp);
 160         return 0;
 161 trunc:
 162         nd_print_trunc(ndo);
 163         return -1;
 164 }
 165
 166 static int
 167 ahcp_ipv4_addresses_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
 168 {
 169         const char *sep = ": ";
 170
 171         while (cp < ep) {
 172                 if (cp + 4 > ep)
 173                         goto invalid;
 174                 ND_TCHECK_4(cp);
 175                 ND_PRINT("%s%s", sep, GET_IPADDR_STRING(cp));
 176                 cp += 4;
 177                 sep = ", ";
 178         }
 179         return 0;
 180
 181 invalid:
 182         nd_print_invalid(ndo);
 183         ND_TCHECK_LEN(cp, ep - cp);
 184         return 0;
 185 trunc:
 186         nd_print_trunc(ndo);
 187         return -1;
 188 }
 189
 190 static int
 191 ahcp_ipv6_prefixes_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
 192 {
 193         const char *sep = ": ";
 194
 195         while (cp < ep) {
 196                 if (cp + 17 > ep)
 197                         goto invalid;
 198                 ND_TCHECK_LEN(cp, 17);
 199                 ND_PRINT("%s%s/%u", sep, GET_IP6ADDR_STRING(cp),
 200                          GET_U_1(cp + 16));
 201                 cp += 17;
 202                 sep = ", ";
 203         }
 204         return 0;
 205
 206 invalid:
 207         nd_print_invalid(ndo);
 208         ND_TCHECK_LEN(cp, ep - cp);
 209         return 0;
 210 trunc:
 211         nd_print_trunc(ndo);
 212         return -1;
 213 }
 214
 215 static int
 216 ahcp_ipv4_prefixes_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
 217 {
 218         const char *sep = ": ";
 219
 220         while (cp < ep) {
 221                 if (cp + 5 > ep)
 222                         goto invalid;
 223                 ND_TCHECK_5(cp);
 224                 ND_PRINT("%s%s/%u", sep, GET_IPADDR_STRING(cp),
 225                          GET_U_1(cp + 4));
 226                 cp += 5;
 227                 sep = ", ";
 228         }
 229         return 0;
 230
 231 invalid:
 232         nd_print_invalid(ndo);
 233         ND_TCHECK_LEN(cp, ep - cp);
 234         return 0;
 235 trunc:
 236         nd_print_trunc(ndo);
 237         return -1;
 238 }
 239
 240 /* Data decoders signal truncated data with -1. */
 241 static int
 242 (* const data_decoders[AHCP1_OPT_MAX + 1])(netdissect_options *, const u_char *, const u_char *) = {
 243         /* [AHCP1_OPT_PAD]                    = */  NULL,
 244         /* [AHCP1_OPT_MANDATORY]              = */  NULL,
 245         /* [AHCP1_OPT_ORIGIN_TIME]            = */  ahcp_time_print,
 246         /* [AHCP1_OPT_EXPIRES]                = */  ahcp_seconds_print,
 247         /* [AHCP1_OPT_MY_IPV6_ADDRESS]        = */  ahcp_ipv6_addresses_print,
 248         /* [AHCP1_OPT_MY_IPV4_ADDRESS]        = */  ahcp_ipv4_addresses_print,
 249         /* [AHCP1_OPT_IPV6_PREFIX]            = */  ahcp_ipv6_prefixes_print,
 250         /* [AHCP1_OPT_IPV4_PREFIX]            = */  NULL,
 251         /* [AHCP1_OPT_IPV6_ADDRESS]           = */  ahcp_ipv6_addresses_print,
 252         /* [AHCP1_OPT_IPV4_ADDRESS]           = */  ahcp_ipv4_addresses_print,
 253         /* [AHCP1_OPT_IPV6_PREFIX_DELEGATION] = */  ahcp_ipv6_prefixes_print,
 254         /* [AHCP1_OPT_IPV4_PREFIX_DELEGATION] = */  ahcp_ipv4_prefixes_print,
 255         /* [AHCP1_OPT_NAME_SERVER]            = */  ahcp_ipv6_addresses_print,
 256         /* [AHCP1_OPT_NTP_SERVER]             = */  ahcp_ipv6_addresses_print,
 257 };
 258
 259 static void
 260 ahcp1_options_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
 261 {
 262         uint8_t option_no, option_len;
 263
 264         while (cp < ep) {
 265                 /* Option no */
 266                 option_no = GET_U_1(cp);
 267                 cp += 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 (cp + 1 > ep)
 273                         goto invalid;
 274                 option_len = GET_U_1(cp);
 275                 cp += 1;
 276                 if (cp + option_len > ep)
 277                         goto invalid;
 278                 /* Value */
 279                 if (option_no <= AHCP1_OPT_MAX && data_decoders[option_no] != NULL) {
 280                         if (data_decoders[option_no](ndo, cp, cp + option_len) < 0)
 281                                 break; /* truncated and already marked up */
 282                 } else {
 283                         ND_PRINT(" (Length %u)", option_len);
 284                         ND_TCHECK_LEN(cp, option_len);
 285                 }
 286                 cp += option_len;
 287         }
 288         return;
 289
 290 invalid:
 291         nd_print_invalid(ndo);
 292         ND_TCHECK_LEN(cp, ep - cp);
 293         return;
 294 trunc:
 295         nd_print_trunc(ndo);
 296 }
 297
 298 static void
 299 ahcp1_body_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
 300 {
 301         uint8_t type, mbz;
 302         uint16_t body_len;
 303
 304         if (cp + AHCP1_BODY_MIN_LEN > ep)
 305                 goto invalid;
 306         /* Type */
 307         type = GET_U_1(cp);
 308         cp += 1;
 309         /* MBZ */
 310         mbz = GET_U_1(cp);
 311         cp += 1;
 312         /* Length */
 313         body_len = GET_BE_U_2(cp);
 314         cp += 2;
 315
 316         if (ndo->ndo_vflag) {
 317                 ND_PRINT("\n\t%s", tok2str(ahcp1_msg_str, "Unknown-%u", type));
 318                 if (mbz != 0)
 319                         ND_PRINT(", MBZ %u", mbz);
 320                 ND_PRINT(", Length %u", body_len);
 321         }
 322         if (cp + body_len > ep)
 323                 goto invalid;
 324
 325         /* Options */
 326         if (ndo->ndo_vflag >= 2)
 327                 ahcp1_options_print(ndo, cp, cp + body_len); /* not ep (ignore extra data) */
 328         else
 329                 ND_TCHECK_LEN(cp, body_len);
 330         return;
 331
 332 invalid:
 333         nd_print_invalid(ndo);
 334         ND_TCHECK_LEN(cp, ep - cp);
 335         return;
 336 trunc:
 337         nd_print_trunc(ndo);
 338 }
 339
 340 void
 341 ahcp_print(netdissect_options *ndo, const u_char *cp, const u_int len)
 342 {
 343         const u_char *ep = ndo->ndo_snapend;
 344         uint8_t version;
 345
 346         ndo->ndo_protocol = "ahcp";
 347         nd_print_protocol_caps(ndo);
 348         if (len < 2)
 349                 goto invalid;
 350         /* Magic */
 351         if (GET_U_1(cp) != AHCP_MAGIC_NUMBER)
 352                 goto invalid;
 353         cp += 1;
 354         /* Version */
 355         version = GET_U_1(cp);
 356         cp += 1;
 357         switch (version) {
 358                 case AHCP_VERSION_1: {
 359                         ND_PRINT(" Version 1");
 360                         if (len < AHCP1_HEADER_FIX_LEN)
 361                                 goto invalid;
 362                         if (!ndo->ndo_vflag) {
 363                                 ND_TCHECK_LEN(cp, AHCP1_HEADER_FIX_LEN - 2);
 364                                 cp += AHCP1_HEADER_FIX_LEN - 2;
 365                         } else {
 366                                 /* Hopcount */
 367                                 ND_PRINT("\n\tHopcount %u", GET_U_1(cp));
 368                                 cp += 1;
 369                                 /* Original Hopcount */
 370                                 ND_PRINT(", Original Hopcount %u",
 371                                          GET_U_1(cp));
 372                                 cp += 1;
 373                                 /* Nonce */
 374                                 ND_PRINT(", Nonce 0x%08x", GET_BE_U_4(cp));
 375                                 cp += 4;
 376                                 /* Source Id */
 377                                 ND_TCHECK_8(cp);
 378                                 ND_PRINT(", Source Id %s", GET_LINKADDR_STRING(cp, LINKADDR_OTHER, 8));
 379                                 cp += 8;
 380                                 /* Destination Id */
 381                                 ND_TCHECK_8(cp);
 382                                 ND_PRINT(", Destination Id %s", GET_LINKADDR_STRING(cp, LINKADDR_OTHER, 8));
 383                                 cp += 8;
 384                         }
 385                         /* Body */
 386                         ahcp1_body_print(ndo, cp, ep);
 387                         break;
 388                 }
 389                 default:
 390                         ND_PRINT(" Version %u (unknown)", version);
 391                         break;
 392         }
 393         return;
 394
 395 invalid:
 396         nd_print_invalid(ndo);
 397         ND_TCHECK_LEN(cp, ep - cp);
 398         return;
 399 trunc:
 400         nd_print_trunc(ndo);
 401 }