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 #define NETDISSECT_REWORKED
  30 #ifdef HAVE_CONFIG_H
  31 #include "config.h"
  32 #endif
  33
  34 #include <tcpdump-stdinc.h>
  35
  36 #include <stdio.h>
  37 #include <string.h>
  38
  39 #include "interface.h"
  40 #include "addrtoname.h"
  41 #include "extract.h"
  42
  43 static const char tstr[] = "[|babel]";
  44
  45 static void babel_print_v2(netdissect_options *, const u_char *cp, u_int length);
  46
  47 void
  48 babel_print(netdissect_options *ndo,
  49             const u_char *cp, u_int length) {
  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     /* Rotating buffer. */
 168     static char buf[2][sizeof("0000.000000s")];
 169     static int x = 0;
 170     x = (x + 1) % 2;
 171     snprintf(buf[x], sizeof(buf[x]), "%u.%06us", i / 1000000, i % 1000000);
 172     return buf[x];
 173 }
 174
 175 /* Return number of octets consumed from the input buffer (not the prefix length
 176  * in bytes), or -1 for encoding error. */
 177 static int
 178 network_prefix(int ae, int plen, unsigned int omitted,
 179                const unsigned char *p, const unsigned char *dp,
 180                unsigned int len, unsigned char *p_r)
 181 {
 182     unsigned pb;
 183     unsigned char prefix[16];
 184     int consumed = 0;
 185
 186     if(plen >= 0)
 187         pb = (plen + 7) / 8;
 188     else if(ae == 1)
 189         pb = 4;
 190     else
 191         pb = 16;
 192
 193     if(pb > 16)
 194         return -1;
 195
 196     memset(prefix, 0, 16);
 197
 198     switch(ae) {
 199     case 0: break;
 200     case 1:
 201         if(omitted > 4 || pb > 4 || (pb > omitted && len < pb - omitted))
 202             return -1;
 203         memcpy(prefix, v4prefix, 12);
 204         if(omitted) {
 205             if (dp == NULL) return -1;
 206             memcpy(prefix, dp, 12 + omitted);
 207         }
 208         if(pb > omitted) {
 209             memcpy(prefix + 12 + omitted, p, pb - omitted);
 210             consumed = pb - omitted;
 211         }
 212         break;
 213     case 2:
 214         if(omitted > 16 || (pb > omitted && len < pb - omitted))
 215             return -1;
 216         if(omitted) {
 217             if (dp == NULL) return -1;
 218             memcpy(prefix, dp, omitted);
 219         }
 220         if(pb > omitted) {
 221             memcpy(prefix + omitted, p, pb - omitted);
 222             consumed = pb - omitted;
 223         }
 224         break;
 225     case 3:
 226         if(pb > 8 && len < pb - 8) return -1;
 227         prefix[0] = 0xfe;
 228         prefix[1] = 0x80;
 229         if(pb > 8) {
 230             memcpy(prefix + 8, p, pb - 8);
 231             consumed = pb - 8;
 232         }
 233         break;
 234     default:
 235         return -1;
 236     }
 237
 238     memcpy(p_r, prefix, 16);
 239     return consumed;
 240 }
 241
 242 static int
 243 network_address(int ae, const unsigned char *a, unsigned int len,
 244                 unsigned char *a_r)
 245 {
 246     return network_prefix(ae, -1, 0, a, NULL, len, a_r);
 247 }
 248
 249 /*
 250  * Sub-TLVs consume the "extra data" of Babel TLVs (see Section 4.3 of RFC6126),
 251  * their encoding is similar to the encoding of TLVs, but the type namespace is
 252  * different:
 253  *
 254  * o Type 0 stands for Pad1 sub-TLV with the same encoding as the Pad1 TLV.
 255  * o Type 1 stands for PadN sub-TLV with the same encoding as the PadN TLV.
 256  * o Type 2 stands for Diversity sub-TLV, which propagates diversity routing
 257  *   data. Its body is a variable-length sequence of 8-bit unsigned integers,
 258  *   each representing per-hop number of interferring radio channel for the
 259  *   prefix. Channel 0 is invalid and must not be used in the sub-TLV, channel
 260  *   255 interferes with any other channel.
 261  * o Type 3 stands for Timestamp sub-TLV, used to compute RTT between
 262  *   neighbours. In the case of a Hello TLV, the body stores a 32-bits
 263  *   timestamp, while in the case of a IHU TLV, two 32-bits timestamps are
 264  *   stored.
 265  *
 266  * Sub-TLV types 0 and 1 are valid for any TLV type, whether sub-TLV type 2 is
 267  * only valid for TLV type 8 (Update). Note that within an Update TLV a missing
 268  * Diversity sub-TLV is not the same as a Diversity sub-TLV with an empty body.
 269  * The former would mean a lack of any claims about the interference, and the
 270  * latter would state that interference is definitely absent.
 271  * A type 3 sub-TLV is valid both for Hello and IHU TLVs, though the exact
 272  * semantic of the sub-TLV is different in each case.
 273  */
 274 static void
 275 subtlvs_print(netdissect_options *ndo,
 276               const u_char *cp, const u_char *ep, const uint8_t tlv_type) {
 277     uint8_t subtype, sublen;
 278     const char *sep;
 279     uint32_t t1, t2;
 280
 281     while (cp < ep) {
 282         subtype = *cp++;
 283         if(subtype == MESSAGE_SUB_PAD1) {
 284             ND_PRINT((ndo, " sub-pad1"));
 285             continue;
 286         }
 287         if(cp == ep)
 288             goto corrupt;
 289         sublen = *cp++;
 290         if(cp + sublen > ep)
 291             goto corrupt;
 292
 293         switch(subtype) {
 294         case MESSAGE_SUB_PADN:
 295             ND_PRINT((ndo, " sub-padn"));
 296             cp += sublen;
 297             break;
 298         case MESSAGE_SUB_DIVERSITY:
 299             ND_PRINT((ndo, " sub-diversity"));
 300             if (sublen == 0) {
 301                 ND_PRINT((ndo, " empty"));
 302                 break;
 303             }
 304             sep = " ";
 305             while(sublen--) {
 306                 ND_PRINT((ndo, "%s%s", sep, tok2str(diversity_str, "%u", *cp++)));
 307                 sep = "-";
 308             }
 309             if(tlv_type != MESSAGE_UPDATE)
 310                 ND_PRINT((ndo, " (bogus)"));
 311             break;
 312         case MESSAGE_SUB_TIMESTAMP:
 313             ND_PRINT((ndo, " sub-timestamp"));
 314             if(tlv_type == MESSAGE_HELLO) {
 315                 if(sublen != 4)
 316                     goto corrupt;
 317                 t1 = EXTRACT_32BITS(cp);
 318                 ND_PRINT((ndo, " %s", format_timestamp(t1)));
 319             } else if(tlv_type == MESSAGE_IHU) {
 320                 if(sublen != 8)
 321                     goto corrupt;
 322                 t1 = EXTRACT_32BITS(cp);
 323                 t2 = EXTRACT_32BITS(cp + 4);
 324                 ND_PRINT((ndo, " %s|%s",
 325                           format_timestamp(t1), format_timestamp(t2)));
 326             } else
 327                 ND_PRINT((ndo, " (bogus)"));
 328             cp += sublen;
 329             break;
 330         default:
 331             ND_PRINT((ndo, " sub-unknown-0x%02x", subtype));
 332             cp += sublen;
 333         } /* switch */
 334     } /* while */
 335     return;
 336
 337  corrupt:
 338     ND_PRINT((ndo, " (corrupt)"));
 339 }
 340
 341 #define ICHECK(i, l) \
 342         if ((i) + (l) > bodylen || (i) + (l) > length) goto corrupt;
 343
 344 static void
 345 babel_print_v2(netdissect_options *ndo,
 346                const u_char *cp, u_int length) {
 347     u_int i;
 348     u_short bodylen;
 349     u_char v4_prefix[16] =
 350         {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xFF, 0xFF, 0, 0, 0, 0 };
 351     u_char v6_prefix[16] = {0};
 352
 353     ND_TCHECK2(*cp, 4);
 354     if (length < 4)
 355         goto corrupt;
 356     bodylen = EXTRACT_16BITS(cp + 2);
 357     ND_PRINT((ndo, " (%u)", bodylen));
 358
 359     /* Process the TLVs in the body */
 360     i = 0;
 361     while(i < bodylen) {
 362         const u_char *message;
 363         u_int type, len;
 364
 365         message = cp + 4 + i;
 366
 367         ND_TCHECK2(*message, 1);
 368         if((type = message[0]) == MESSAGE_PAD1) {
 369             ND_PRINT((ndo, ndo->ndo_vflag ? "\n\tPad 1" : " pad1"));
 370             i += 1;
 371             continue;
 372         }
 373
 374         ND_TCHECK2(*message, 2);
 375         ICHECK(i, 2);
 376         len = message[1];
 377
 378         ND_TCHECK2(*message, 2 + len);
 379         ICHECK(i, 2 + len);
 380
 381         switch(type) {
 382         case MESSAGE_PADN: {
 383             if (!ndo->ndo_vflag)
 384                 ND_PRINT((ndo, " padN"));
 385             else
 386                 ND_PRINT((ndo, "\n\tPad %d", len + 2));
 387         }
 388             break;
 389
 390         case MESSAGE_ACK_REQ: {
 391             u_short nonce, interval;
 392             if (!ndo->ndo_vflag)
 393                 ND_PRINT((ndo, " ack-req"));
 394             else {
 395                 ND_PRINT((ndo, "\n\tAcknowledgment Request "));
 396                 if(len < 6) goto corrupt;
 397                 nonce = EXTRACT_16BITS(message + 4);
 398                 interval = EXTRACT_16BITS(message + 6);
 399                 ND_PRINT((ndo, "%04x %s", nonce, format_interval(interval)));
 400             }
 401         }
 402             break;
 403
 404         case MESSAGE_ACK: {
 405             u_short nonce;
 406             if (!ndo->ndo_vflag)
 407                 ND_PRINT((ndo, " ack"));
 408             else {
 409                 ND_PRINT((ndo, "\n\tAcknowledgment "));
 410                 if(len < 2) goto corrupt;
 411                 nonce = EXTRACT_16BITS(message + 2);
 412                 ND_PRINT((ndo, "%04x", nonce));
 413             }
 414         }
 415             break;
 416
 417         case MESSAGE_HELLO:  {
 418             u_short seqno, interval;
 419             if (!ndo->ndo_vflag)
 420                 ND_PRINT((ndo, " hello"));
 421             else {
 422                 ND_PRINT((ndo, "\n\tHello "));
 423                 if(len < 6) goto corrupt;
 424                 seqno = EXTRACT_16BITS(message + 4);
 425                 interval = EXTRACT_16BITS(message + 6);
 426                 ND_PRINT((ndo, "seqno %u interval %s", seqno, format_interval(interval)));
 427                 /* Extra data. */
 428                 if(len > 6)
 429                     subtlvs_print(ndo, message + 8, message + 2 + len, type);
 430             }
 431         }
 432             break;
 433
 434         case MESSAGE_IHU: {
 435             unsigned short txcost, interval;
 436             if (!ndo->ndo_vflag)
 437                 ND_PRINT((ndo, " ihu"));
 438             else {
 439                 u_char address[16];
 440                 int rc;
 441                 ND_PRINT((ndo, "\n\tIHU "));
 442                 if(len < 6) goto corrupt;
 443                 txcost = EXTRACT_16BITS(message + 4);
 444                 interval = EXTRACT_16BITS(message + 6);
 445                 rc = network_address(message[2], message + 8, len - 6, address);
 446                 if(rc < 0) { ND_PRINT((ndo, "%s", tstr)); break; }
 447                 ND_PRINT((ndo, "%s txcost %u interval %s",
 448                        format_address(ndo, address), txcost, format_interval(interval)));
 449                 /* Extra data. */
 450                 if((u_int)rc < len - 6)
 451                     subtlvs_print(ndo, message + 8 + rc, message + 2 + len,
 452                                   type);
 453             }
 454         }
 455             break;
 456
 457         case MESSAGE_ROUTER_ID: {
 458             if (!ndo->ndo_vflag)
 459                 ND_PRINT((ndo, " router-id"));
 460             else {
 461                 ND_PRINT((ndo, "\n\tRouter Id"));
 462                 if(len < 10) goto corrupt;
 463                 ND_PRINT((ndo, " %s", format_id(message + 4)));
 464             }
 465         }
 466             break;
 467
 468         case MESSAGE_NH: {
 469             if (!ndo->ndo_vflag)
 470                 ND_PRINT((ndo, " nh"));
 471             else {
 472                 int rc;
 473                 u_char nh[16];
 474                 ND_PRINT((ndo, "\n\tNext Hop"));
 475                 if(len < 2) goto corrupt;
 476                 rc = network_address(message[2], message + 4, len - 2, nh);
 477                 if(rc < 0) goto corrupt;
 478                 ND_PRINT((ndo, " %s", format_address(ndo, nh)));
 479             }
 480         }
 481             break;
 482
 483         case MESSAGE_UPDATE: {
 484             if (!ndo->ndo_vflag) {
 485                 ND_PRINT((ndo, " update"));
 486                 if(len < 1)
 487                     ND_PRINT((ndo, "/truncated"));
 488                 else
 489                     ND_PRINT((ndo, "%s%s%s",
 490                            (message[3] & 0x80) ? "/prefix": "",
 491                            (message[3] & 0x40) ? "/id" : "",
 492                            (message[3] & 0x3f) ? "/unknown" : ""));
 493             } else {
 494                 u_short interval, seqno, metric;
 495                 u_char plen;
 496                 int rc;
 497                 u_char prefix[16];
 498                 ND_PRINT((ndo, "\n\tUpdate"));
 499                 if(len < 10) goto corrupt;
 500                 plen = message[4] + (message[2] == 1 ? 96 : 0);
 501                 rc = network_prefix(message[2], message[4], message[5],
 502                                     message + 12,
 503                                     message[2] == 1 ? v4_prefix : v6_prefix,
 504                                     len - 10, prefix);
 505                 if(rc < 0) goto corrupt;
 506                 interval = EXTRACT_16BITS(message + 6);
 507                 seqno = EXTRACT_16BITS(message + 8);
 508                 metric = EXTRACT_16BITS(message + 10);
 509                 ND_PRINT((ndo, "%s%s%s %s metric %u seqno %u interval %s",
 510                        (message[3] & 0x80) ? "/prefix": "",
 511                        (message[3] & 0x40) ? "/id" : "",
 512                        (message[3] & 0x3f) ? "/unknown" : "",
 513                        format_prefix(ndo, prefix, plen),
 514                        metric, seqno, format_interval_update(interval)));
 515                 if(message[3] & 0x80) {
 516                     if(message[2] == 1)
 517                         memcpy(v4_prefix, prefix, 16);
 518                     else
 519                         memcpy(v6_prefix, prefix, 16);
 520                 }
 521                 /* extra data? */
 522                 if((u_int)rc < len - 10)
 523                     subtlvs_print(ndo, message + 12 + rc, message + 2 + len, type);
 524             }
 525         }
 526             break;
 527
 528         case MESSAGE_REQUEST: {
 529             if (!ndo->ndo_vflag)
 530                 ND_PRINT((ndo, " request"));
 531             else {
 532                 int rc;
 533                 u_char prefix[16], plen;
 534                 ND_PRINT((ndo, "\n\tRequest "));
 535                 if(len < 2) goto corrupt;
 536                 plen = message[3] + (message[2] == 1 ? 96 : 0);
 537                 rc = network_prefix(message[2], message[3], 0,
 538                                     message + 4, NULL, len - 2, prefix);
 539                 if(rc < 0) goto corrupt;
 540                 ND_PRINT((ndo, "for %s",
 541                        message[2] == 0 ? "any" : format_prefix(ndo, prefix, plen)));
 542             }
 543         }
 544             break;
 545
 546         case MESSAGE_MH_REQUEST : {
 547             if (!ndo->ndo_vflag)
 548                 ND_PRINT((ndo, " mh-request"));
 549             else {
 550                 int rc;
 551                 u_short seqno;
 552                 u_char prefix[16], plen;
 553                 ND_PRINT((ndo, "\n\tMH-Request "));
 554                 if(len < 14) goto corrupt;
 555                 seqno = EXTRACT_16BITS(message + 4);
 556                 rc = network_prefix(message[2], message[3], 0,
 557                                     message + 16, NULL, len - 14, prefix);
 558                 if(rc < 0) goto corrupt;
 559                 plen = message[3] + (message[2] == 1 ? 96 : 0);
 560                 ND_PRINT((ndo, "(%u hops) for %s seqno %u id %s",
 561                        message[6], format_prefix(ndo, prefix, plen),
 562                        seqno, format_id(message + 8)));
 563             }
 564         }
 565             break;
 566         case MESSAGE_TSPC :
 567             if (!ndo->ndo_vflag)
 568                 ND_PRINT((ndo, " tspc"));
 569             else {
 570                 ND_PRINT((ndo, "\n\tTS/PC "));
 571                 if(len < 6) goto corrupt;
 572                 ND_PRINT((ndo, "timestamp %u packetcounter %u", EXTRACT_32BITS (message + 4),
 573                        EXTRACT_16BITS(message + 2)));
 574             }
 575             break;
 576         case MESSAGE_HMAC : {
 577             if (!ndo->ndo_vflag)
 578                 ND_PRINT((ndo, " hmac"));
 579             else {
 580                 unsigned j;
 581                 ND_PRINT((ndo, "\n\tHMAC "));
 582                 if(len < 18) goto corrupt;
 583                 ND_PRINT((ndo, "key-id %u digest-%u ", EXTRACT_16BITS(message + 2), len - 2));
 584                 for (j = 0; j < len - 2; j++)
 585                     ND_PRINT((ndo, "%02X", message[4 + j]));
 586             }
 587         }
 588             break;
 589         default:
 590             if (!ndo->ndo_vflag)
 591                 ND_PRINT((ndo, " unknown"));
 592             else
 593                 ND_PRINT((ndo, "\n\tUnknown message type %d", type));
 594         }
 595         i += len + 2;
 596     }
 597     return;
 598
 599  trunc:
 600     ND_PRINT((ndo, " %s", tstr));
 601     return;
 602
 603  corrupt:
 604     ND_PRINT((ndo, " (corrupt)"));
 605     return;
 606 }