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 static const char tstr[] = " [|ahcp]";
  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 int
 101 ahcp_time_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
 102 {
 103         time_t t;
 104         struct tm *tm;
 105         char buf[BUFSIZE];
 106
 107         if (cp + 4 != ep)
 108                 goto invalid;
 109         ND_TCHECK_4(cp);
 110         t = EXTRACT_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 0;
 118
 119 invalid:
 120         ND_PRINT("%s", istr);
 121         ND_TCHECK_LEN(cp, ep - cp);
 122         return 0;
 123 trunc:
 124         ND_PRINT("%s", tstr);
 125         return -1;
 126 }
 127
 128 static int
 129 ahcp_seconds_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
 130 {
 131         if (cp + 4 != ep)
 132                 goto invalid;
 133         ND_TCHECK_4(cp);
 134         ND_PRINT(": %us", EXTRACT_BE_U_4(cp));
 135         return 0;
 136
 137 invalid:
 138         ND_PRINT("%s", istr);
 139         ND_TCHECK_LEN(cp, ep - cp);
 140         return 0;
 141 trunc:
 142         ND_PRINT("%s", tstr);
 143         return -1;
 144 }
 145
 146 static int
 147 ahcp_ipv6_addresses_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
 148 {
 149         const char *sep = ": ";
 150
 151         while (cp < ep) {
 152                 if (cp + 16 > ep)
 153                         goto invalid;
 154                 ND_TCHECK_16(cp);
 155                 ND_PRINT("%s%s", sep, ip6addr_string(ndo, cp));
 156                 cp += 16;
 157                 sep = ", ";
 158         }
 159         return 0;
 160
 161 invalid:
 162         ND_PRINT("%s", istr);
 163         ND_TCHECK_LEN(cp, ep - cp);
 164         return 0;
 165 trunc:
 166         ND_PRINT("%s", tstr);
 167         return -1;
 168 }
 169
 170 static int
 171 ahcp_ipv4_addresses_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
 172 {
 173         const char *sep = ": ";
 174
 175         while (cp < ep) {
 176                 if (cp + 4 > ep)
 177                         goto invalid;
 178                 ND_TCHECK_4(cp);
 179                 ND_PRINT("%s%s", sep, ipaddr_string(ndo, cp));
 180                 cp += 4;
 181                 sep = ", ";
 182         }
 183         return 0;
 184
 185 invalid:
 186         ND_PRINT("%s", istr);
 187         ND_TCHECK_LEN(cp, ep - cp);
 188         return 0;
 189 trunc:
 190         ND_PRINT("%s", tstr);
 191         return -1;
 192 }
 193
 194 static int
 195 ahcp_ipv6_prefixes_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
 196 {
 197         const char *sep = ": ";
 198
 199         while (cp < ep) {
 200                 if (cp + 17 > ep)
 201                         goto invalid;
 202                 ND_TCHECK_LEN(cp, 17);
 203                 ND_PRINT("%s%s/%u", sep, ip6addr_string(ndo, cp), EXTRACT_U_1(cp + 16));
 204                 cp += 17;
 205                 sep = ", ";
 206         }
 207         return 0;
 208
 209 invalid:
 210         ND_PRINT("%s", istr);
 211         ND_TCHECK_LEN(cp, ep - cp);
 212         return 0;
 213 trunc:
 214         ND_PRINT("%s", tstr);
 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), EXTRACT_U_1(cp + 4));
 228                 cp += 5;
 229                 sep = ", ";
 230         }
 231         return 0;
 232
 233 invalid:
 234         ND_PRINT("%s", istr);
 235         ND_TCHECK_LEN(cp, ep - cp);
 236         return 0;
 237 trunc:
 238         ND_PRINT("%s", tstr);
 239         return -1;
 240 }
 241
 242 /* Data decoders signal truncated data with -1. */
 243 static int
 244 (* const data_decoders[AHCP1_OPT_MAX + 1])(netdissect_options *, const u_char *, const u_char *) = {
 245         /* [AHCP1_OPT_PAD]                    = */  NULL,
 246         /* [AHCP1_OPT_MANDATORY]              = */  NULL,
 247         /* [AHCP1_OPT_ORIGIN_TIME]            = */  ahcp_time_print,
 248         /* [AHCP1_OPT_EXPIRES]                = */  ahcp_seconds_print,
 249         /* [AHCP1_OPT_MY_IPV6_ADDRESS]        = */  ahcp_ipv6_addresses_print,
 250         /* [AHCP1_OPT_MY_IPV4_ADDRESS]        = */  ahcp_ipv4_addresses_print,
 251         /* [AHCP1_OPT_IPV6_PREFIX]            = */  ahcp_ipv6_prefixes_print,
 252         /* [AHCP1_OPT_IPV4_PREFIX]            = */  NULL,
 253         /* [AHCP1_OPT_IPV6_ADDRESS]           = */  ahcp_ipv6_addresses_print,
 254         /* [AHCP1_OPT_IPV4_ADDRESS]           = */  ahcp_ipv4_addresses_print,
 255         /* [AHCP1_OPT_IPV6_PREFIX_DELEGATION] = */  ahcp_ipv6_prefixes_print,
 256         /* [AHCP1_OPT_IPV4_PREFIX_DELEGATION] = */  ahcp_ipv4_prefixes_print,
 257         /* [AHCP1_OPT_NAME_SERVER]            = */  ahcp_ipv6_addresses_print,
 258         /* [AHCP1_OPT_NTP_SERVER]             = */  ahcp_ipv6_addresses_print,
 259 };
 260
 261 static void
 262 ahcp1_options_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
 263 {
 264         uint8_t option_no, option_len;
 265
 266         while (cp < ep) {
 267                 /* Option no */
 268                 ND_TCHECK_1(cp);
 269                 option_no = EXTRACT_U_1(cp);
 270                 cp += 1;
 271                 ND_PRINT("\n\t %s", tok2str(ahcp1_opt_str, "Unknown-%u", option_no));
 272                 if (option_no == AHCP1_OPT_PAD || option_no == AHCP1_OPT_MANDATORY)
 273                         continue;
 274                 /* Length */
 275                 if (cp + 1 > ep)
 276                         goto invalid;
 277                 ND_TCHECK_1(cp);
 278                 option_len = EXTRACT_U_1(cp);
 279                 cp += 1;
 280                 if (cp + option_len > ep)
 281                         goto invalid;
 282                 /* Value */
 283                 if (option_no <= AHCP1_OPT_MAX && data_decoders[option_no] != NULL) {
 284                         if (data_decoders[option_no](ndo, cp, cp + option_len) < 0)
 285                                 break; /* truncated and already marked up */
 286                 } else {
 287                         ND_PRINT(" (Length %u)", option_len);
 288                         ND_TCHECK_LEN(cp, option_len);
 289                 }
 290                 cp += option_len;
 291         }
 292         return;
 293
 294 invalid:
 295         ND_PRINT("%s", istr);
 296         ND_TCHECK_LEN(cp, ep - cp);
 297         return;
 298 trunc:
 299         ND_PRINT("%s", tstr);
 300 }
 301
 302 static void
 303 ahcp1_body_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
 304 {
 305         uint8_t type, mbz;
 306         uint16_t body_len;
 307
 308         if (cp + AHCP1_BODY_MIN_LEN > ep)
 309                 goto invalid;
 310         /* Type */
 311         ND_TCHECK_1(cp);
 312         type = EXTRACT_U_1(cp);
 313         cp += 1;
 314         /* MBZ */
 315         ND_TCHECK_1(cp);
 316         mbz = EXTRACT_U_1(cp);
 317         cp += 1;
 318         /* Length */
 319         ND_TCHECK_2(cp);
 320         body_len = EXTRACT_BE_U_2(cp);
 321         cp += 2;
 322
 323         if (ndo->ndo_vflag) {
 324                 ND_PRINT("\n\t%s", tok2str(ahcp1_msg_str, "Unknown-%u", type));
 325                 if (mbz != 0)
 326                         ND_PRINT(", MBZ %u", mbz);
 327                 ND_PRINT(", Length %u", body_len);
 328         }
 329         if (cp + body_len > ep)
 330                 goto invalid;
 331
 332         /* Options */
 333         if (ndo->ndo_vflag >= 2)
 334                 ahcp1_options_print(ndo, cp, cp + body_len); /* not ep (ignore extra data) */
 335         else
 336                 ND_TCHECK_LEN(cp, body_len);
 337         return;
 338
 339 invalid:
 340         ND_PRINT("%s", istr);
 341         ND_TCHECK_LEN(cp, ep - cp);
 342         return;
 343 trunc:
 344         ND_PRINT("%s", tstr);
 345 }
 346
 347 void
 348 ahcp_print(netdissect_options *ndo, const u_char *cp, const u_int len)
 349 {
 350         const u_char *ep = ndo->ndo_snapend;
 351         uint8_t version;
 352
 353         ndo->ndo_protocol = "ahcp";
 354         ND_PRINT("AHCP");
 355         if (len < 2)
 356                 goto invalid;
 357         /* Magic */
 358         ND_TCHECK_1(cp);
 359         if (EXTRACT_U_1(cp) != AHCP_MAGIC_NUMBER)
 360                 goto invalid;
 361         cp += 1;
 362         /* Version */
 363         ND_TCHECK_1(cp);
 364         version = EXTRACT_U_1(cp);
 365         cp += 1;
 366         switch (version) {
 367                 case AHCP_VERSION_1: {
 368                         ND_PRINT(" Version 1");
 369                         if (len < AHCP1_HEADER_FIX_LEN)
 370                                 goto invalid;
 371                         if (!ndo->ndo_vflag) {
 372                                 ND_TCHECK_LEN(cp, AHCP1_HEADER_FIX_LEN - 2);
 373                                 cp += AHCP1_HEADER_FIX_LEN - 2;
 374                         } else {
 375                                 /* Hopcount */
 376                                 ND_TCHECK_1(cp);
 377                                 ND_PRINT("\n\tHopcount %u", EXTRACT_U_1(cp));
 378                                 cp += 1;
 379                                 /* Original Hopcount */
 380                                 ND_TCHECK_1(cp);
 381                                 ND_PRINT(", Original Hopcount %u", EXTRACT_U_1(cp));
 382                                 cp += 1;
 383                                 /* Nonce */
 384                                 ND_TCHECK_4(cp);
 385                                 ND_PRINT(", Nonce 0x%08x", EXTRACT_BE_U_4(cp));
 386                                 cp += 4;
 387                                 /* Source Id */
 388                                 ND_TCHECK_8(cp);
 389                                 ND_PRINT(", Source Id %s", linkaddr_string(ndo, cp, 0, 8));
 390                                 cp += 8;
 391                                 /* Destination Id */
 392                                 ND_TCHECK_8(cp);
 393                                 ND_PRINT(", Destination Id %s", linkaddr_string(ndo, cp, 0, 8));
 394                                 cp += 8;
 395                         }
 396                         /* Body */
 397                         ahcp1_body_print(ndo, cp, ep);
 398                         break;
 399                 }
 400                 default:
 401                         ND_PRINT(" Version %u (unknown)", version);
 402                         break;
 403         }
 404         return;
 405
 406 invalid:
 407         ND_PRINT("%s", istr);
 408         ND_TCHECK_LEN(cp, ep - cp);
 409         return;
 410 trunc:
 411         ND_PRINT("%s", tstr);
 412 }