The Tcpdump Group git mirrors - tcpdump/blob - print-ahcp.c

   1 /*
   2  * This module implements decoding of AHCP (Ad Hoc Configuration Protocol) based
   3  * on draft-chroboczek-ahcp-00 and source code of ahcpd-0.53.
   4  *
   5  *
   6  * Copyright (c) 2013 The TCPDUMP project
   7  * All rights reserved.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  21  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  22  * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  23  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
  24  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  25  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  26  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
  28  * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  29  * POSSIBILITY OF SUCH DAMAGE.
  30  */
  31
  32 #ifdef HAVE_CONFIG_H
  33 #include "config.h"
  34 #endif
  35
  36 #include <tcpdump-stdinc.h>
  37
  38 #include "interface.h"
  39 #include "extract.h"
  40 #include "addrtoname.h"
  41
  42 static const char *corrupt_str = "(corrupt)";
  43 static const char *trunc_str = "[|ahcp]";
  44
  45 #define AHCP_MAGIC_NUMBER 43
  46 #define AHCP_VERSION_1 1
  47 #define AHCP1_HEADER_FIX_LEN 24
  48 #define AHCP1_BODY_MIN_LEN 4
  49
  50 #define AHCP1_MSG_DISCOVER 0
  51 #define AHCP1_MSG_OFFER    1
  52 #define AHCP1_MSG_REQUEST  2
  53 #define AHCP1_MSG_ACK      3
  54 #define AHCP1_MSG_NACK     4
  55 #define AHCP1_MSG_RELEASE  5
  56
  57 static const struct tok ahcp1_msg_str[] = {
  58         { AHCP1_MSG_DISCOVER, "Discover" },
  59         { AHCP1_MSG_OFFER,    "Offer"    },
  60         { AHCP1_MSG_REQUEST,  "Request"  },
  61         { AHCP1_MSG_ACK,      "Ack"      },
  62         { AHCP1_MSG_NACK,     "Nack"     },
  63         { AHCP1_MSG_RELEASE,  "Release"  },
  64         { 0, NULL }
  65 };
  66
  67 #define AHCP1_OPT_PAD                     0
  68 #define AHCP1_OPT_MANDATORY               1
  69 #define AHCP1_OPT_ORIGIN_TIME             2
  70 #define AHCP1_OPT_EXPIRES                 3
  71 #define AHCP1_OPT_MY_IPV6_ADDRESS         4
  72 #define AHCP1_OPT_MY_IPV4_ADDRESS         5
  73 #define AHCP1_OPT_IPV6_PREFIX             6
  74 #define AHCP1_OPT_IPV4_PREFIX             7
  75 #define AHCP1_OPT_IPV6_ADDRESS            8
  76 #define AHCP1_OPT_IPV4_ADDRESS            9
  77 #define AHCP1_OPT_IPV6_PREFIX_DELEGATION 10
  78 #define AHCP1_OPT_IPV4_PREFIX_DELEGATION 11
  79 #define AHCP1_OPT_NAME_SERVER            12
  80 #define AHCP1_OPT_NTP_SERVER             13
  81 #define AHCP1_OPT_MAX                    13
  82
  83 static const struct tok ahcp1_opt_str[] = {
  84         { AHCP1_OPT_PAD,                    "Pad"                    },
  85         { AHCP1_OPT_MANDATORY,              "Mandatory"              },
  86         { AHCP1_OPT_ORIGIN_TIME,            "Origin Time"            },
  87         { AHCP1_OPT_EXPIRES,                "Expires"                },
  88         { AHCP1_OPT_MY_IPV6_ADDRESS,        "My-IPv6-Address"        },
  89         { AHCP1_OPT_MY_IPV4_ADDRESS,        "My-IPv4-Address"        },
  90         { AHCP1_OPT_IPV6_PREFIX,            "IPv6 Prefix"            },
  91         { AHCP1_OPT_IPV4_PREFIX,            "IPv4 Prefix"            },
  92         { AHCP1_OPT_IPV6_ADDRESS,           "IPv6 Address"           },
  93         { AHCP1_OPT_IPV4_ADDRESS,           "IPv4 Address"           },
  94         { AHCP1_OPT_IPV6_PREFIX_DELEGATION, "IPv6 Prefix Delegation" },
  95         { AHCP1_OPT_IPV4_PREFIX_DELEGATION, "IPv4 Prefix Delegation" },
  96         { AHCP1_OPT_NAME_SERVER,            "Name Server"            },
  97         { AHCP1_OPT_NTP_SERVER,             "NTP Server"             },
  98         { 0, NULL }
  99 };
 100
 101 static int
 102 ahcp_time_print(const u_char *cp, const u_char *ep) {
 103         time_t t;
 104         struct tm *tm;
 105         char buf[BUFSIZE];
 106
 107         if (cp + 4 != ep)
 108                 goto corrupt;
 109         TCHECK2(*cp, 4);
 110         t = EXTRACT_32BITS(cp);
 111         if (NULL == (tm = gmtime(&t)))
 112                 printf(": gmtime() error");
 113         else if (0 == strftime(buf, sizeof(buf), "%Y-%m-%d %H:%M:%S", tm))
 114                 printf(": strftime() error");
 115         else
 116                 printf(": %s UTC", buf);
 117         return 0;
 118
 119 corrupt:
 120         printf(": %s", corrupt_str);
 121         TCHECK2(*cp, ep - cp);
 122         return 0;
 123 trunc:
 124         printf(" %s", trunc_str);
 125         return -1;
 126 }
 127
 128 static int
 129 ahcp_seconds_print(const u_char *cp, const u_char *ep) {
 130         if (cp + 4 != ep)
 131                 goto corrupt;
 132         TCHECK2(*cp, 4);
 133         printf(": %us", EXTRACT_32BITS(cp));
 134         return 0;
 135
 136 corrupt:
 137         printf(": %s", corrupt_str);
 138         TCHECK2(*cp, ep - cp);
 139         return 0;
 140 trunc:
 141         printf(" %s", trunc_str);
 142         return -1;
 143 }
 144
 145 static int
 146 ahcp_ipv6_addresses_print(const u_char *cp, const u_char *ep) {
 147         const char *sep = ": ";
 148
 149         while (cp < ep) {
 150                 if (cp + 16 > ep)
 151                         goto corrupt;
 152                 TCHECK2(*cp, 16);
 153                 printf("%s%s", sep,
 154 #ifdef INET6
 155                        ip6addr_string(cp)
 156 #else
 157                        "(compiled w/o IPv6)"
 158 #endif /* INET6 */
 159                        );
 160                 cp += 16;
 161                 sep = ", ";
 162         }
 163         return 0;
 164
 165 corrupt:
 166         printf(": %s", corrupt_str);
 167         TCHECK2(*cp, ep - cp);
 168         return 0;
 169 trunc:
 170         printf(" %s", trunc_str);
 171         return -1;
 172 }
 173
 174 static int
 175 ahcp_ipv4_addresses_print(const u_char *cp, const u_char *ep) {
 176         const char *sep = ": ";
 177
 178         while (cp < ep) {
 179                 if (cp + 4 > ep)
 180                         goto corrupt;
 181                 TCHECK2(*cp, 4);
 182                 printf("%s%s", sep, ipaddr_string(cp));
 183                 cp += 4;
 184                 sep = ", ";
 185         }
 186         return 0;
 187
 188 corrupt:
 189         printf(": %s", corrupt_str);
 190         TCHECK2(*cp, ep - cp);
 191         return 0;
 192 trunc:
 193         printf(" %s", trunc_str);
 194         return -1;
 195 }
 196
 197 static int
 198 ahcp_ipv6_prefixes_print(const u_char *cp, const u_char *ep) {
 199         const char *sep = ": ";
 200
 201         while (cp < ep) {
 202                 if (cp + 17 > ep)
 203                         goto corrupt;
 204                 TCHECK2(*cp, 17);
 205                 printf("%s%s/%u", sep,
 206 #ifdef INET6
 207                        ip6addr_string(cp),
 208 #else
 209                        "(compiled w/o IPv6)",
 210 #endif /* INET6 */
 211                        *(cp + 16));
 212                 cp += 17;
 213                 sep = ", ";
 214         }
 215         return 0;
 216
 217 corrupt:
 218         printf(": %s", corrupt_str);
 219         TCHECK2(*cp, ep - cp);
 220         return 0;
 221 trunc:
 222         printf(" %s", trunc_str);
 223         return -1;
 224 }
 225
 226 static int
 227 ahcp_ipv4_prefixes_print(const u_char *cp, const u_char *ep) {
 228         const char *sep = ": ";
 229
 230         while (cp < ep) {
 231                 if (cp + 5 > ep)
 232                         goto corrupt;
 233                 TCHECK2(*cp, 5);
 234                 printf("%s%s/%u", sep, ipaddr_string(cp), *(cp + 4));
 235                 cp += 5;
 236                 sep = ", ";
 237         }
 238         return 0;
 239
 240 corrupt:
 241         printf(": %s", corrupt_str);
 242         TCHECK2(*cp, ep - cp);
 243         return 0;
 244 trunc:
 245         printf(" %s", trunc_str);
 246         return -1;
 247 }
 248
 249 /* Data decoders signal truncated data with -1. */
 250 static int
 251 (* const data_decoders[AHCP1_OPT_MAX + 1])(const u_char *, const u_char *) = {
 252         /* [AHCP1_OPT_PAD]                    = */  NULL,
 253         /* [AHCP1_OPT_MANDATORY]              = */  NULL,
 254         /* [AHCP1_OPT_ORIGIN_TIME]            = */  ahcp_time_print,
 255         /* [AHCP1_OPT_EXPIRES]                = */  ahcp_seconds_print,
 256         /* [AHCP1_OPT_MY_IPV6_ADDRESS]        = */  ahcp_ipv6_addresses_print,
 257         /* [AHCP1_OPT_MY_IPV4_ADDRESS]        = */  ahcp_ipv4_addresses_print,
 258         /* [AHCP1_OPT_IPV6_PREFIX]            = */  ahcp_ipv6_prefixes_print,
 259         /* [AHCP1_OPT_IPV4_PREFIX]            = */  NULL,
 260         /* [AHCP1_OPT_IPV6_ADDRESS]           = */  ahcp_ipv6_addresses_print,
 261         /* [AHCP1_OPT_IPV4_ADDRESS]           = */  ahcp_ipv4_addresses_print,
 262         /* [AHCP1_OPT_IPV6_PREFIX_DELEGATION] = */  ahcp_ipv6_prefixes_print,
 263         /* [AHCP1_OPT_IPV4_PREFIX_DELEGATION] = */  ahcp_ipv4_prefixes_print,
 264         /* [AHCP1_OPT_NAME_SERVER]            = */  ahcp_ipv6_addresses_print,
 265         /* [AHCP1_OPT_NTP_SERVER]             = */  ahcp_ipv6_addresses_print,
 266 };
 267
 268 static void
 269 ahcp1_options_print(const u_char *cp, const u_char *ep) {
 270         uint8_t option_no, option_len;
 271
 272         while (cp < ep) {
 273                 /* Option no */
 274                 TCHECK2(*cp, 1);
 275                 option_no = *cp;
 276                 cp += 1;
 277                 printf("\n\t %s", tok2str(ahcp1_opt_str, "Unknown-%u", option_no));
 278                 if (option_no == AHCP1_OPT_PAD || option_no == AHCP1_OPT_MANDATORY)
 279                         continue;
 280                 /* Length */
 281                 if (cp + 1 > ep)
 282                         goto corrupt;
 283                 TCHECK2(*cp, 1);
 284                 option_len = *cp;
 285                 cp += 1;
 286                 if (cp + option_len > ep)
 287                         goto corrupt;
 288                 /* Value */
 289                 if (option_no <= AHCP1_OPT_MAX && data_decoders[option_no] != NULL) {
 290                         if (data_decoders[option_no](cp, cp + option_len) < 0)
 291                                 break; /* truncated and already marked up */
 292                 } else {
 293                         printf(" (Length %u)", option_len);
 294                         TCHECK2(*cp, option_len);
 295                 }
 296                 cp += option_len;
 297         }
 298         return;
 299
 300 corrupt:
 301         printf(" %s", corrupt_str);
 302         TCHECK2(*cp, ep - cp);
 303         return;
 304 trunc:
 305         printf(" %s", trunc_str);
 306 }
 307
 308 static void
 309 ahcp1_body_print(const u_char *cp, const u_char *ep) {
 310         uint8_t type, mbz;
 311         uint16_t body_len;
 312
 313         if (cp + AHCP1_BODY_MIN_LEN > ep)
 314                 goto corrupt;
 315         /* Type */
 316         TCHECK2(*cp, 1);
 317         type = *cp;
 318         cp += 1;
 319         /* MBZ */
 320         TCHECK2(*cp, 1);
 321         mbz = *cp;
 322         cp += 1;
 323         /* Length */
 324         TCHECK2(*cp, 2);
 325         body_len = EXTRACT_16BITS(cp);
 326         cp += 2;
 327
 328         if (vflag) {
 329                 printf("\n\t%s", tok2str(ahcp1_msg_str, "Unknown-%u", type));
 330                 if (mbz != 0)
 331                         printf(", MBZ %u", mbz);
 332                 printf(", Length %u", body_len);
 333         }
 334         if (cp + body_len > ep)
 335                 goto corrupt;
 336
 337         /* Options */
 338         if (vflag >= 2)
 339                 ahcp1_options_print(cp, cp + body_len); /* not ep (ignore extra data) */
 340         else
 341                 TCHECK2(*cp, body_len);
 342         return;
 343
 344 corrupt:
 345         printf(" %s", corrupt_str);
 346         TCHECK2(*cp, ep - cp);
 347         return;
 348 trunc:
 349         printf(" %s", trunc_str);
 350 }
 351
 352 void
 353 ahcp_print(const u_char *cp, const u_int len) {
 354         const u_char *ep = cp + len;
 355         uint8_t version;
 356
 357         printf("AHCP");
 358         if (len < 2)
 359                 goto corrupt;
 360         /* Magic */
 361         TCHECK2(*cp, 1);
 362         if (*cp != AHCP_MAGIC_NUMBER)
 363                 goto corrupt;
 364         cp += 1;
 365         /* Version */
 366         TCHECK2(*cp, 1);
 367         version = *cp;
 368         cp += 1;
 369         switch (version) {
 370                 case AHCP_VERSION_1: {
 371                         printf(" Version 1");
 372                         if (len < AHCP1_HEADER_FIX_LEN)
 373                                 goto corrupt;
 374                         if (!vflag) {
 375                                 TCHECK2(*cp, AHCP1_HEADER_FIX_LEN - 2);
 376                                 cp += AHCP1_HEADER_FIX_LEN - 2;
 377                         } else {
 378                                 /* Hopcount */
 379                                 TCHECK2(*cp, 1);
 380                                 printf("\n\tHopcount %u", *cp);
 381                                 cp += 1;
 382                                 /* Original Hopcount */
 383                                 TCHECK2(*cp, 1);
 384                                 printf(", Original Hopcount %u", *cp);
 385                                 cp += 1;
 386                                 /* Nonce */
 387                                 TCHECK2(*cp, 4);
 388                                 printf(", Nonce 0x%08x", EXTRACT_32BITS(cp));
 389                                 cp += 4;
 390                                 /* Source Id */
 391                                 TCHECK2(*cp, 8);
 392                                 printf(", Source Id %s", linkaddr_string(cp, 0, 8));
 393                                 cp += 8;
 394                                 /* Destination Id */
 395                                 TCHECK2(*cp, 8);
 396                                 printf(", Destination Id %s", linkaddr_string(cp, 0, 8));
 397                                 cp += 8;
 398                         }
 399                         /* Body */
 400                         ahcp1_body_print(cp, ep);
 401                         break;
 402                 }
 403                 default:
 404                         printf(" Version %u (unknown)", version);
 405                         break;
 406         }
 407         return;
 408
 409 corrupt:
 410         printf(" %s", corrupt_str);
 411         TCHECK2(*cp, ep - cp);
 412         return;
 413 trunc:
 414         printf(" %s", trunc_str);
 415 }
 416