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

   1 /*
   2  * Copyright (c) 2007-2011 Grégoire Henry, Juliusz Chroboczek
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  * 3. Neither the name of the project nor the names of its contributors
  13  *    may be used to endorse or promote products derived from this software
  14  *    without specific prior written permission.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
  20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  */
  28
  29 #ifdef HAVE_CONFIG_H
  30 #include "config.h"
  31 #endif
  32
  33 #include <tcpdump-stdinc.h>
  34
  35 #include <stdio.h>
  36 #include <string.h>
  37
  38 #include "interface.h"
  39 #include "addrtoname.h"
  40 #include "extract.h"
  41
  42 static const char tstr[] = "[|babel]";
  43
  44 static void babel_print_v2(netdissect_options *, const u_char *cp, u_int length);
  45
  46 void
  47 babel_print(netdissect_options *ndo,
  48             const u_char *cp, u_int length)
  49 {
  50     ND_PRINT((ndo, "babel"));
  51
  52     ND_TCHECK2(*cp, 4);
  53
  54     if(cp[0] != 42) {
  55         ND_PRINT((ndo, " malformed header"));
  56         return;
  57     } else {
  58         ND_PRINT((ndo, " %d", cp[1]));
  59     }
  60
  61     switch(cp[1]) {
  62     case 2:
  63         babel_print_v2(ndo, cp, length);
  64         break;
  65     default:
  66         ND_PRINT((ndo, " unknown version"));
  67         break;
  68     }
  69
  70     return;
  71
  72  trunc:
  73     ND_PRINT((ndo, " %s", tstr));
  74     return;
  75 }
  76
  77 /* TLVs */
  78 #define MESSAGE_PAD1 0
  79 #define MESSAGE_PADN 1
  80 #define MESSAGE_ACK_REQ 2
  81 #define MESSAGE_ACK 3
  82 #define MESSAGE_HELLO 4
  83 #define MESSAGE_IHU 5
  84 #define MESSAGE_ROUTER_ID 6
  85 #define MESSAGE_NH 7
  86 #define MESSAGE_UPDATE 8
  87 #define MESSAGE_REQUEST 9
  88 #define MESSAGE_MH_REQUEST 10
  89 #define MESSAGE_TSPC 11
  90 #define MESSAGE_HMAC 12
  91
  92 /* sub-TLVs */
  93 #define MESSAGE_SUB_PAD1 0
  94 #define MESSAGE_SUB_PADN 1
  95 #define MESSAGE_SUB_DIVERSITY 2
  96 #define MESSAGE_SUB_TIMESTAMP 3
  97
  98 /* Diversity sub-TLV channel codes */
  99 static const struct tok diversity_str[] = {
 100     { 0,   "reserved" },
 101     { 255, "all"      },
 102     { 0, NULL }
 103 };
 104
 105 static const char *
 106 format_id(const u_char *id)
 107 {
 108     static char buf[25];
 109     snprintf(buf, 25, "%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x",
 110              id[0], id[1], id[2], id[3], id[4], id[5], id[6], id[7]);
 111     buf[24] = '\0';
 112     return buf;
 113 }
 114
 115 static const unsigned char v4prefix[16] =
 116     {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xFF, 0xFF, 0, 0, 0, 0 };
 117
 118 static const char *
 119 format_prefix(netdissect_options *ndo, const u_char *prefix, unsigned char plen)
 120 {
 121     static char buf[50];
 122     if(plen >= 96 && memcmp(prefix, v4prefix, 12) == 0)
 123         snprintf(buf, 50, "%s/%u", ipaddr_string(ndo, prefix + 12), plen - 96);
 124     else
 125 #ifdef INET6
 126         snprintf(buf, 50, "%s/%u", ip6addr_string(ndo, prefix), plen);
 127 #else
 128         snprintf(buf, 50, "IPv6 addresses not supported");
 129 #endif
 130     buf[49] = '\0';
 131     return buf;
 132 }
 133
 134 static const char *
 135 format_address(netdissect_options *ndo, const u_char *prefix)
 136 {
 137     if(memcmp(prefix, v4prefix, 12) == 0)
 138         return ipaddr_string(ndo, prefix + 12);
 139     else
 140 #ifdef INET6
 141         return ip6addr_string(ndo, prefix);
 142 #else
 143         return "IPv6 addresses not supported";
 144 #endif
 145 }
 146
 147 static const char *
 148 format_interval(const uint16_t i)
 149 {
 150     static char buf[sizeof("000.00s")];
 151
 152     if (i == 0)
 153         return "0.0s (bogus)";
 154     snprintf(buf, sizeof(buf), "%u.%02us", i / 100, i % 100);
 155     return buf;
 156 }
 157
 158 static const char *
 159 format_interval_update(const uint16_t i)
 160 {
 161     return i == 0xFFFF ? "infinity" : format_interval(i);
 162 }
 163
 164 static const char *
 165 format_timestamp(const uint32_t i)
 166 {
 167     static char buf[sizeof("0000.000000s")];
 168     snprintf(buf, sizeof(buf), "%u.%06us", i / 1000000, i % 1000000);
 169     return buf;
 170 }
 171
 172 /* Return number of octets consumed from the input buffer (not the prefix length
 173  * in bytes), or -1 for encoding error. */
 174 static int
 175 network_prefix(int ae, int plen, unsigned int omitted,
 176                const unsigned char *p, const unsigned char *dp,
 177                unsigned int len, unsigned char *p_r)
 178 {
 179     unsigned pb;
 180     unsigned char prefix[16];
 181     int consumed = 0;
 182
 183     if(plen >= 0)
 184         pb = (plen + 7) / 8;
 185     else if(ae == 1)
 186         pb = 4;
 187     else
 188         pb = 16;
 189
 190     if(pb > 16)
 191         return -1;
 192
 193     memset(prefix, 0, 16);
 194
 195     switch(ae) {
 196     case 0: break;
 197     case 1:
 198         if(omitted > 4 || pb > 4 || (pb > omitted && len < pb - omitted))
 199             return -1;
 200         memcpy(prefix, v4prefix, 12);
 201         if(omitted) {
 202             if (dp == NULL) return -1;
 203             memcpy(prefix, dp, 12 + omitted);
 204         }
 205         if(pb > omitted) {
 206             memcpy(prefix + 12 + omitted, p, pb - omitted);
 207             consumed = pb - omitted;
 208         }
 209         break;
 210     case 2:
 211         if(omitted > 16 || (pb > omitted && len < pb - omitted))
 212             return -1;
 213         if(omitted) {
 214             if (dp == NULL) return -1;
 215             memcpy(prefix, dp, omitted);
 216         }
 217         if(pb > omitted) {
 218             memcpy(prefix + omitted, p, pb - omitted);
 219             consumed = pb - omitted;
 220         }
 221         break;
 222     case 3:
 223         if(pb > 8 && len < pb - 8) return -1;
 224         prefix[0] = 0xfe;
 225         prefix[1] = 0x80;
 226         if(pb > 8) {
 227             memcpy(prefix + 8, p, pb - 8);
 228             consumed = pb - 8;
 229         }
 230         break;
 231     default:
 232         return -1;
 233     }
 234
 235     memcpy(p_r, prefix, 16);
 236     return consumed;
 237 }
 238
 239 static int
 240 network_address(int ae, const unsigned char *a, unsigned int len,
 241                 unsigned char *a_r)
 242 {
 243     return network_prefix(ae, -1, 0, a, NULL, len, a_r);
 244 }
 245
 246 /*
 247  * Sub-TLVs consume the "extra data" of Babel TLVs (see Section 4.3 of RFC6126),
 248  * their encoding is similar to the encoding of TLVs, but the type namespace is
 249  * different:
 250  *
 251  * o Type 0 stands for Pad1 sub-TLV with the same encoding as the Pad1 TLV.
 252  * o Type 1 stands for PadN sub-TLV with the same encoding as the PadN TLV.
 253  * o Type 2 stands for Diversity sub-TLV, which propagates diversity routing
 254  *   data. Its body is a variable-length sequence of 8-bit unsigned integers,
 255  *   each representing per-hop number of interferring radio channel for the
 256  *   prefix. Channel 0 is invalid and must not be used in the sub-TLV, channel
 257  *   255 interferes with any other channel.
 258  * o Type 3 stands for Timestamp sub-TLV, used to compute RTT between
 259  *   neighbours. In the case of a Hello TLV, the body stores a 32-bits
 260  *   timestamp, while in the case of a IHU TLV, two 32-bits timestamps are
 261  *   stored.
 262  *
 263  * Sub-TLV types 0 and 1 are valid for any TLV type, whether sub-TLV type 2 is
 264  * only valid for TLV type 8 (Update). Note that within an Update TLV a missing
 265  * Diversity sub-TLV is not the same as a Diversity sub-TLV with an empty body.
 266  * The former would mean a lack of any claims about the interference, and the
 267  * latter would state that interference is definitely absent.
 268  * A type 3 sub-TLV is valid both for Hello and IHU TLVs, though the exact
 269  * semantic of the sub-TLV is different in each case.
 270  */
 271 static void
 272 subtlvs_print(netdissect_options *ndo,
 273               const u_char *cp, const u_char *ep, const uint8_t tlv_type)
 274 {
 275     uint8_t subtype, sublen;
 276     const char *sep;
 277     uint32_t t1, t2;
 278
 279     while (cp < ep) {
 280         subtype = *cp++;
 281         if(subtype == MESSAGE_SUB_PAD1) {
 282             ND_PRINT((ndo, " sub-pad1"));
 283             continue;
 284         }
 285         if(cp == ep)
 286             goto corrupt;
 287         sublen = *cp++;
 288         if(cp + sublen > ep)
 289             goto corrupt;
 290
 291         switch(subtype) {
 292         case MESSAGE_SUB_PADN:
 293             ND_PRINT((ndo, " sub-padn"));
 294             cp += sublen;
 295             break;
 296         case MESSAGE_SUB_DIVERSITY:
 297             ND_PRINT((ndo, " sub-diversity"));
 298             if (sublen == 0) {
 299                 ND_PRINT((ndo, " empty"));
 300                 break;
 301             }
 302             sep = " ";
 303             while(sublen--) {
 304                 ND_PRINT((ndo, "%s%s", sep, tok2str(diversity_str, "%u", *cp++)));
 305                 sep = "-";
 306             }
 307             if(tlv_type != MESSAGE_UPDATE)
 308                 ND_PRINT((ndo, " (bogus)"));
 309             break;
 310         case MESSAGE_SUB_TIMESTAMP:
 311             ND_PRINT((ndo, " sub-timestamp"));
 312             if(tlv_type == MESSAGE_HELLO) {
 313                 if(sublen < 4)
 314                     goto corrupt;
 315                 t1 = EXTRACT_32BITS(cp);
 316                 ND_PRINT((ndo, " %s", format_timestamp(t1)));
 317             } else if(tlv_type == MESSAGE_IHU) {
 318                 if(sublen < 8)
 319                     goto corrupt;
 320                 t1 = EXTRACT_32BITS(cp);
 321                 ND_PRINT((ndo, " %s", format_timestamp(t1)));
 322                 t2 = EXTRACT_32BITS(cp + 4);
 323                 ND_PRINT((ndo, "|%s", format_timestamp(t2)));
 324             } else
 325                 ND_PRINT((ndo, " (bogus)"));
 326             cp += sublen;
 327             break;
 328         default:
 329             ND_PRINT((ndo, " sub-unknown-0x%02x", subtype));
 330             cp += sublen;
 331         } /* switch */
 332     } /* while */
 333     return;
 334
 335  corrupt:
 336     ND_PRINT((ndo, " (corrupt)"));
 337 }
 338
 339 #define ICHECK(i, l) \
 340         if ((i) + (l) > bodylen || (i) + (l) > length) goto corrupt;
 341
 342 static void
 343 babel_print_v2(netdissect_options *ndo,
 344                const u_char *cp, u_int length)
 345 {
 346     u_int i;
 347     u_short bodylen;
 348     u_char v4_prefix[16] =
 349         {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xFF, 0xFF, 0, 0, 0, 0 };
 350     u_char v6_prefix[16] = {0};
 351
 352     ND_TCHECK2(*cp, 4);
 353     if (length < 4)
 354         goto corrupt;
 355     bodylen = EXTRACT_16BITS(cp + 2);
 356     ND_PRINT((ndo, " (%u)", bodylen));
 357
 358     /* Process the TLVs in the body */
 359     i = 0;
 360     while(i < bodylen) {
 361         const u_char *message;
 362         u_int type, len;
 363
 364         message = cp + 4 + i;
 365
 366         ND_TCHECK2(*message, 1);
 367         if((type = message[0]) == MESSAGE_PAD1) {
 368             ND_PRINT((ndo, ndo->ndo_vflag ? "\n\tPad 1" : " pad1"));
 369             i += 1;
 370             continue;
 371         }
 372
 373         ND_TCHECK2(*message, 2);
 374         ICHECK(i, 2);
 375         len = message[1];
 376
 377         ND_TCHECK2(*message, 2 + len);
 378         ICHECK(i, 2 + len);
 379
 380         switch(type) {
 381         case MESSAGE_PADN: {
 382             if (!ndo->ndo_vflag)
 383                 ND_PRINT((ndo, " padN"));
 384             else
 385                 ND_PRINT((ndo, "\n\tPad %d", len + 2));
 386         }
 387             break;
 388
 389         case MESSAGE_ACK_REQ: {
 390             u_short nonce, interval;
 391             if (!ndo->ndo_vflag)
 392                 ND_PRINT((ndo, " ack-req"));
 393             else {
 394                 ND_PRINT((ndo, "\n\tAcknowledgment Request "));
 395                 if(len < 6) goto corrupt;
 396                 nonce = EXTRACT_16BITS(message + 4);
 397                 interval = EXTRACT_16BITS(message + 6);
 398                 ND_PRINT((ndo, "%04x %s", nonce, format_interval(interval)));
 399             }
 400         }
 401             break;
 402
 403         case MESSAGE_ACK: {
 404             u_short nonce;
 405             if (!ndo->ndo_vflag)
 406                 ND_PRINT((ndo, " ack"));
 407             else {
 408                 ND_PRINT((ndo, "\n\tAcknowledgment "));
 409                 if(len < 2) goto corrupt;
 410                 nonce = EXTRACT_16BITS(message + 2);
 411                 ND_PRINT((ndo, "%04x", nonce));
 412             }
 413         }
 414             break;
 415
 416         case MESSAGE_HELLO:  {
 417             u_short seqno, interval;
 418             if (!ndo->ndo_vflag)
 419                 ND_PRINT((ndo, " hello"));
 420             else {
 421                 ND_PRINT((ndo, "\n\tHello "));
 422                 if(len < 6) goto corrupt;
 423                 seqno = EXTRACT_16BITS(message + 4);
 424                 interval = EXTRACT_16BITS(message + 6);
 425                 ND_PRINT((ndo, "seqno %u interval %s", seqno, format_interval(interval)));
 426                 /* Extra data. */
 427                 if(len > 6)
 428                     subtlvs_print(ndo, message + 8, message + 2 + len, type);
 429             }
 430         }
 431             break;
 432
 433         case MESSAGE_IHU: {
 434             unsigned short txcost, interval;
 435             if (!ndo->ndo_vflag)
 436                 ND_PRINT((ndo, " ihu"));
 437             else {
 438                 u_char address[16];
 439                 int rc;
 440                 ND_PRINT((ndo, "\n\tIHU "));
 441                 if(len < 6) goto corrupt;
 442                 txcost = EXTRACT_16BITS(message + 4);
 443                 interval = EXTRACT_16BITS(message + 6);
 444                 rc = network_address(message[2], message + 8, len - 6, address);
 445                 if(rc < 0) { ND_PRINT((ndo, "%s", tstr)); break; }
 446                 ND_PRINT((ndo, "%s txcost %u interval %s",
 447                        format_address(ndo, address), txcost, format_interval(interval)));
 448                 /* Extra data. */
 449                 if((u_int)rc < len - 6)
 450                     subtlvs_print(ndo, message + 8 + rc, message + 2 + len,
 451                                   type);
 452             }
 453         }
 454             break;
 455
 456         case MESSAGE_ROUTER_ID: {
 457             if (!ndo->ndo_vflag)
 458                 ND_PRINT((ndo, " router-id"));
 459             else {
 460                 ND_PRINT((ndo, "\n\tRouter Id"));
 461                 if(len < 10) goto corrupt;
 462                 ND_PRINT((ndo, " %s", format_id(message + 4)));
 463             }
 464         }
 465             break;
 466
 467         case MESSAGE_NH: {
 468             if (!ndo->ndo_vflag)
 469                 ND_PRINT((ndo, " nh"));
 470             else {
 471                 int rc;
 472                 u_char nh[16];
 473                 ND_PRINT((ndo, "\n\tNext Hop"));
 474                 if(len < 2) goto corrupt;
 475                 rc = network_address(message[2], message + 4, len - 2, nh);
 476                 if(rc < 0) goto corrupt;
 477                 ND_PRINT((ndo, " %s", format_address(ndo, nh)));
 478             }
 479         }
 480             break;
 481
 482         case MESSAGE_UPDATE: {
 483             if (!ndo->ndo_vflag) {
 484                 ND_PRINT((ndo, " update"));
 485                 if(len < 1)
 486                     ND_PRINT((ndo, "/truncated"));
 487                 else
 488                     ND_PRINT((ndo, "%s%s%s",
 489                            (message[3] & 0x80) ? "/prefix": "",
 490                            (message[3] & 0x40) ? "/id" : "",
 491                            (message[3] & 0x3f) ? "/unknown" : ""));
 492             } else {
 493                 u_short interval, seqno, metric;
 494                 u_char plen;
 495                 int rc;
 496                 u_char prefix[16];
 497                 ND_PRINT((ndo, "\n\tUpdate"));
 498                 if(len < 10) goto corrupt;
 499                 plen = message[4] + (message[2] == 1 ? 96 : 0);
 500                 rc = network_prefix(message[2], message[4], message[5],
 501                                     message + 12,
 502                                     message[2] == 1 ? v4_prefix : v6_prefix,
 503                                     len - 10, prefix);
 504                 if(rc < 0) goto corrupt;
 505                 interval = EXTRACT_16BITS(message + 6);
 506                 seqno = EXTRACT_16BITS(message + 8);
 507                 metric = EXTRACT_16BITS(message + 10);
 508                 ND_PRINT((ndo, "%s%s%s %s metric %u seqno %u interval %s",
 509                        (message[3] & 0x80) ? "/prefix": "",
 510                        (message[3] & 0x40) ? "/id" : "",
 511                        (message[3] & 0x3f) ? "/unknown" : "",
 512                        format_prefix(ndo, prefix, plen),
 513                        metric, seqno, format_interval_update(interval)));
 514                 if(message[3] & 0x80) {
 515                     if(message[2] == 1)
 516                         memcpy(v4_prefix, prefix, 16);
 517                     else
 518                         memcpy(v6_prefix, prefix, 16);
 519                 }
 520                 /* extra data? */
 521                 if((u_int)rc < len - 10)
 522                     subtlvs_print(ndo, message + 12 + rc, message + 2 + len, type);
 523             }
 524         }
 525             break;
 526
 527         case MESSAGE_REQUEST: {
 528             if (!ndo->ndo_vflag)
 529                 ND_PRINT((ndo, " request"));
 530             else {
 531                 int rc;
 532                 u_char prefix[16], plen;
 533                 ND_PRINT((ndo, "\n\tRequest "));
 534                 if(len < 2) goto corrupt;
 535                 plen = message[3] + (message[2] == 1 ? 96 : 0);
 536                 rc = network_prefix(message[2], message[3], 0,
 537                                     message + 4, NULL, len - 2, prefix);
 538                 if(rc < 0) goto corrupt;
 539                 ND_PRINT((ndo, "for %s",
 540                        message[2] == 0 ? "any" : format_prefix(ndo, prefix, plen)));
 541             }
 542         }
 543             break;
 544
 545         case MESSAGE_MH_REQUEST : {
 546             if (!ndo->ndo_vflag)
 547                 ND_PRINT((ndo, " mh-request"));
 548             else {
 549                 int rc;
 550                 u_short seqno;
 551                 u_char prefix[16], plen;
 552                 ND_PRINT((ndo, "\n\tMH-Request "));
 553                 if(len < 14) goto corrupt;
 554                 seqno = EXTRACT_16BITS(message + 4);
 555                 rc = network_prefix(message[2], message[3], 0,
 556                                     message + 16, NULL, len - 14, prefix);
 557                 if(rc < 0) goto corrupt;
 558                 plen = message[3] + (message[2] == 1 ? 96 : 0);
 559                 ND_PRINT((ndo, "(%u hops) for %s seqno %u id %s",
 560                        message[6], format_prefix(ndo, prefix, plen),
 561                        seqno, format_id(message + 8)));
 562             }
 563         }
 564             break;
 565         case MESSAGE_TSPC :
 566             if (!ndo->ndo_vflag)
 567                 ND_PRINT((ndo, " tspc"));
 568             else {
 569                 ND_PRINT((ndo, "\n\tTS/PC "));
 570                 if(len < 6) goto corrupt;
 571                 ND_PRINT((ndo, "timestamp %u packetcounter %u", EXTRACT_32BITS (message + 4),
 572                        EXTRACT_16BITS(message + 2)));
 573             }
 574             break;
 575         case MESSAGE_HMAC : {
 576             if (!ndo->ndo_vflag)
 577                 ND_PRINT((ndo, " hmac"));
 578             else {
 579                 unsigned j;
 580                 ND_PRINT((ndo, "\n\tHMAC "));
 581                 if(len < 18) goto corrupt;
 582                 ND_PRINT((ndo, "key-id %u digest-%u ", EXTRACT_16BITS(message + 2), len - 2));
 583                 for (j = 0; j < len - 2; j++)
 584                     ND_PRINT((ndo, "%02X", message[4 + j]));
 585             }
 586         }
 587             break;
 588         default:
 589             if (!ndo->ndo_vflag)
 590                 ND_PRINT((ndo, " unknown"));
 591             else
 592                 ND_PRINT((ndo, "\n\tUnknown message type %d", type));
 593         }
 594         i += len + 2;
 595     }
 596     return;
 597
 598  trunc:
 599     ND_PRINT((ndo, " %s", tstr));
 600     return;
 601
 602  corrupt:
 603     ND_PRINT((ndo, " (corrupt)"));
 604     return;
 605 }