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

   1 /*
   2  * Copyright (c) 1992, 1993, 1994, 1995, 1996, 1997
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that: (1) source code distributions
   7  * retain the above copyright notice and this paragraph in its entirety, (2)
   8  * distributions including binary code include the above copyright notice and
   9  * this paragraph in its entirety in the documentation or other materials
  10  * provided with the distribution, and (3) all advertising materials mentioning
  11  * features or use of this software display the following acknowledgement:
  12  * ``This product includes software developed by the University of California,
  13  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
  14  * the University nor the names of its contributors may be used to endorse
  15  * or promote products derived from this software without specific prior
  16  * written permission.
  17  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
  18  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  19  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  20  *
  21  * Code by Matt Thomas, Digital Equipment Corporation
  22  *      with an awful lot of hacking by Jeffrey Mogul, DECWRL
  23  */
  24
  25 #ifdef HAVE_CONFIG_H
  26 #include "config.h"
  27 #endif
  28
  29 #include <tcpdump-stdinc.h>
  30
  31 #include "netdissect.h"
  32 #include "addrtoname.h"
  33 #include "extract.h"                    /* must come after interface.h */
  34
  35 #include "llc.h"
  36 #include "ethertype.h"
  37 #include "oui.h"
  38
  39 static const struct tok llc_values[] = {
  40         { LLCSAP_NULL,     "Null" },
  41         { LLCSAP_GLOBAL,   "Global" },
  42         { LLCSAP_8021B_I,  "802.1B I" },
  43         { LLCSAP_8021B_G,  "802.1B G" },
  44         { LLCSAP_IP,       "IP" },
  45         { LLCSAP_SNA,      "SNA" },
  46         { LLCSAP_PROWAYNM, "ProWay NM" },
  47         { LLCSAP_8021D,    "STP" },
  48         { LLCSAP_RS511,    "RS511" },
  49         { LLCSAP_ISO8208,  "ISO8208" },
  50         { LLCSAP_PROWAY,   "ProWay" },
  51         { LLCSAP_SNAP,     "SNAP" },
  52         { LLCSAP_IPX,      "IPX" },
  53         { LLCSAP_NETBEUI,  "NetBeui" },
  54         { LLCSAP_ISONS,    "OSI" },
  55         { 0,               NULL },
  56 };
  57
  58 static const struct tok llc_cmd_values[] = {
  59         { LLC_UI,       "ui" },
  60         { LLC_TEST,     "test" },
  61         { LLC_XID,      "xid" },
  62         { LLC_UA,       "ua" },
  63         { LLC_DISC,     "disc" },
  64         { LLC_DM,       "dm" },
  65         { LLC_SABME,    "sabme" },
  66         { LLC_FRMR,     "frmr" },
  67         { 0,            NULL }
  68 };
  69
  70 static const struct tok llc_flag_values[] = {
  71         { 0, "Command" },
  72         { LLC_GSAP, "Response" },
  73         { LLC_U_POLL, "Poll" },
  74         { LLC_GSAP|LLC_U_POLL, "Final" },
  75         { LLC_IS_POLL, "Poll" },
  76         { LLC_GSAP|LLC_IS_POLL, "Final" },
  77         { 0, NULL }
  78 };
  79
  80
  81 static const struct tok llc_ig_flag_values[] = {
  82         { 0, "Individual" },
  83         { LLC_IG, "Group" },
  84         { 0, NULL }
  85 };
  86
  87
  88 static const struct tok llc_supervisory_values[] = {
  89         { 0, "Receiver Ready" },
  90         { 1, "Receiver not Ready" },
  91         { 2, "Reject" },
  92         { 0,             NULL }
  93 };
  94
  95
  96 static const struct tok cisco_values[] = {
  97         { PID_CISCO_CDP, "CDP" },
  98         { PID_CISCO_VTP, "VTP" },
  99         { PID_CISCO_DTP, "DTP" },
 100         { PID_CISCO_UDLD, "UDLD" },
 101         { PID_CISCO_PVST, "PVST" },
 102         { PID_CISCO_VLANBRIDGE, "VLAN Bridge" },
 103         { 0,             NULL }
 104 };
 105
 106 static const struct tok bridged_values[] = {
 107         { PID_RFC2684_ETH_FCS,     "Ethernet + FCS" },
 108         { PID_RFC2684_ETH_NOFCS,   "Ethernet w/o FCS" },
 109         { PID_RFC2684_802_4_FCS,   "802.4 + FCS" },
 110         { PID_RFC2684_802_4_NOFCS, "802.4 w/o FCS" },
 111         { PID_RFC2684_802_5_FCS,   "Token Ring + FCS" },
 112         { PID_RFC2684_802_5_NOFCS, "Token Ring w/o FCS" },
 113         { PID_RFC2684_FDDI_FCS,    "FDDI + FCS" },
 114         { PID_RFC2684_FDDI_NOFCS,  "FDDI w/o FCS" },
 115         { PID_RFC2684_802_6_FCS,   "802.6 + FCS" },
 116         { PID_RFC2684_802_6_NOFCS, "802.6 w/o FCS" },
 117         { PID_RFC2684_BPDU,        "BPDU" },
 118         { 0,                       NULL },
 119 };
 120
 121 static const struct tok null_values[] = {
 122         { 0,             NULL }
 123 };
 124
 125 struct oui_tok {
 126         uint32_t        oui;
 127         const struct tok *tok;
 128 };
 129
 130 static const struct oui_tok oui_to_tok[] = {
 131         { OUI_ENCAP_ETHER, ethertype_values },
 132         { OUI_CISCO_90, ethertype_values },     /* uses some Ethertype values */
 133         { OUI_APPLETALK, ethertype_values },    /* uses some Ethertype values */
 134         { OUI_CISCO, cisco_values },
 135         { OUI_RFC2684, bridged_values },        /* bridged, RFC 2427 FR or RFC 2864 ATM */
 136         { 0, NULL }
 137 };
 138
 139 /*
 140  * If we printed information about the payload, returns the length of the LLC
 141  * header, plus the length of any SNAP header following it.
 142  *
 143  * Otherwise (for example, if the packet has unknown SAPs or has a SNAP
 144  * header with an unknown OUI/PID combination), returns the *negative*
 145  * of that value.
 146  */
 147 int
 148 llc_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen,
 149           const u_char *esrc, const u_char *edst)
 150 {
 151         uint8_t dsap_field, dsap, ssap_field, ssap;
 152         uint16_t control;
 153         u_int hdrlen;
 154         int is_u;
 155
 156         if (caplen < 3) {
 157                 ND_PRINT((ndo, "[|llc]"));
 158                 ND_DEFAULTPRINT((const u_char *)p, caplen);
 159                 return (caplen);
 160         }
 161         if (length < 3) {
 162                 ND_PRINT((ndo, "[|llc]"));
 163                 ND_DEFAULTPRINT((const u_char *)p, caplen);
 164                 return (length);
 165         }
 166
 167         dsap_field = *p;
 168         ssap_field = *(p + 1);
 169
 170         /*
 171          * OK, what type of LLC frame is this?  The length
 172          * of the control field depends on that - I frames
 173          * have a two-byte control field, and U frames have
 174          * a one-byte control field.
 175          */
 176         control = *(p + 2);
 177         if ((control & LLC_U_FMT) == LLC_U_FMT) {
 178                 /*
 179                  * U frame.
 180                  */
 181                 is_u = 1;
 182                 hdrlen = 3;     /* DSAP, SSAP, 1-byte control field */
 183         } else {
 184                 /*
 185                  * The control field in I and S frames is
 186                  * 2 bytes...
 187                  */
 188                 if (caplen < 4) {
 189                         ND_PRINT((ndo, "[|llc]"));
 190                         ND_DEFAULTPRINT((const u_char *)p, caplen);
 191                         return (caplen);
 192                 }
 193                 if (length < 4) {
 194                         ND_PRINT((ndo, "[|llc]"));
 195                         ND_DEFAULTPRINT((const u_char *)p, caplen);
 196                         return (length);
 197                 }
 198
 199                 /*
 200                  * ...and is little-endian.
 201                  */
 202                 control = EXTRACT_LE_16BITS(p + 2);
 203                 is_u = 0;
 204                 hdrlen = 4;     /* DSAP, SSAP, 2-byte control field */
 205         }
 206
 207         if (ssap_field == LLCSAP_GLOBAL && dsap_field == LLCSAP_GLOBAL) {
 208                 /*
 209                  * This is an Ethernet_802.3 IPX frame; it has an
 210                  * 802.3 header (i.e., an Ethernet header where the
 211                  * type/length field is <= ETHERMTU, i.e. it's a length
 212                  * field, not a type field), but has no 802.2 header -
 213                  * the IPX packet starts right after the Ethernet header,
 214                  * with a signature of two bytes of 0xFF (which is
 215                  * LLCSAP_GLOBAL).
 216                  *
 217                  * (It might also have been an Ethernet_802.3 IPX at
 218                  * one time, but got bridged onto another network,
 219                  * such as an 802.11 network; this has appeared in at
 220                  * least one capture file.)
 221                  */
 222
 223             if (ndo->ndo_eflag)
 224                 ND_PRINT((ndo, "IPX 802.3: "));
 225
 226             ipx_print(ndo, p, length);
 227             return (0);         /* no LLC header */
 228         }
 229
 230         dsap = dsap_field & ~LLC_IG;
 231         ssap = ssap_field & ~LLC_GSAP;
 232
 233         if (ndo->ndo_eflag) {
 234                 ND_PRINT((ndo, "LLC, dsap %s (0x%02x) %s, ssap %s (0x%02x) %s",
 235                        tok2str(llc_values, "Unknown", dsap),
 236                        dsap,
 237                        tok2str(llc_ig_flag_values, "Unknown", dsap_field & LLC_IG),
 238                        tok2str(llc_values, "Unknown", ssap),
 239                        ssap,
 240                        tok2str(llc_flag_values, "Unknown", ssap_field & LLC_GSAP)));
 241
 242                 if (is_u) {
 243                         ND_PRINT((ndo, ", ctrl 0x%02x: ", control));
 244                 } else {
 245                         ND_PRINT((ndo, ", ctrl 0x%04x: ", control));
 246                 }
 247         }
 248
 249         /*
 250          * Skip LLC header.
 251          */
 252         p += hdrlen;
 253         length -= hdrlen;
 254         caplen -= hdrlen;
 255
 256         if (ssap == LLCSAP_SNAP && dsap == LLCSAP_SNAP
 257             && control == LLC_UI) {
 258                 /*
 259                  * XXX - what *is* the right bridge pad value here?
 260                  * Does anybody ever bridge one form of LAN traffic
 261                  * over a networking type that uses 802.2 LLC?
 262                  */
 263                 if (!snap_print(ndo, p, length, caplen, esrc, edst, 2)) {
 264                         /*
 265                          * Unknown packet type; tell our caller, by
 266                          * returning a negative value, so they
 267                          * can print the raw packet.
 268                          */
 269                         return (-(hdrlen + 5)); /* include LLC and SNAP header */
 270                 } else
 271                         return (hdrlen + 5);    /* include LLC and SNAP header */
 272         }
 273
 274         if (ssap == LLCSAP_8021D && dsap == LLCSAP_8021D &&
 275             control == LLC_UI) {
 276                 stp_print(ndo, p, length);
 277                 return (hdrlen);
 278         }
 279
 280         if (ssap == LLCSAP_IP && dsap == LLCSAP_IP &&
 281             control == LLC_UI) {
 282                 /*
 283                  * This is an RFC 948-style IP packet, with
 284                  * an 802.3 header and an 802.2 LLC header
 285                  * with the source and destination SAPs being
 286                  * the IP SAP.
 287                  */
 288                 ip_print(ndo, p, length);
 289                 return (hdrlen);
 290         }
 291
 292         if (ssap == LLCSAP_IPX && dsap == LLCSAP_IPX &&
 293             control == LLC_UI) {
 294                 /*
 295                  * This is an Ethernet_802.2 IPX frame, with an 802.3
 296                  * header and an 802.2 LLC header with the source and
 297                  * destination SAPs being the IPX SAP.
 298                  */
 299                 if (ndo->ndo_eflag)
 300                         ND_PRINT((ndo, "IPX 802.2: "));
 301
 302                 ipx_print(ndo, p, length);
 303                 return (hdrlen);
 304         }
 305
 306 #ifdef TCPDUMP_DO_SMB
 307         if (ssap == LLCSAP_NETBEUI && dsap == LLCSAP_NETBEUI
 308             && (!(control & LLC_S_FMT) || control == LLC_U_FMT)) {
 309                 /*
 310                  * we don't actually have a full netbeui parser yet, but the
 311                  * smb parser can handle many smb-in-netbeui packets, which
 312                  * is very useful, so we call that
 313                  *
 314                  * We don't call it for S frames, however, just I frames
 315                  * (which are frames that don't have the low-order bit,
 316                  * LLC_S_FMT, set in the first byte of the control field)
 317                  * and UI frames (whose control field is just 3, LLC_U_FMT).
 318                  */
 319                 netbeui_print(ndo, control, p, length);
 320                 return (hdrlen);
 321         }
 322 #endif
 323         if (ssap == LLCSAP_ISONS && dsap == LLCSAP_ISONS
 324             && control == LLC_UI) {
 325                 isoclns_print(ndo, p, length, caplen);
 326                 return (hdrlen);
 327         }
 328
 329         if (!ndo->ndo_eflag) {
 330                 if (ssap == dsap) {
 331                         if (esrc == NULL || edst == NULL)
 332                                 ND_PRINT((ndo, "%s ", tok2str(llc_values, "Unknown DSAP 0x%02x", dsap)));
 333                         else
 334                                 ND_PRINT((ndo, "%s > %s %s ",
 335                                                 etheraddr_string(ndo, esrc),
 336                                                 etheraddr_string(ndo, edst),
 337                                                 tok2str(llc_values, "Unknown DSAP 0x%02x", dsap)));
 338                 } else {
 339                         if (esrc == NULL || edst == NULL)
 340                                 ND_PRINT((ndo, "%s > %s ",
 341                                         tok2str(llc_values, "Unknown SSAP 0x%02x", ssap),
 342                                         tok2str(llc_values, "Unknown DSAP 0x%02x", dsap)));
 343                         else
 344                                 ND_PRINT((ndo, "%s %s > %s %s ",
 345                                         etheraddr_string(ndo, esrc),
 346                                         tok2str(llc_values, "Unknown SSAP 0x%02x", ssap),
 347                                         etheraddr_string(ndo, edst),
 348                                         tok2str(llc_values, "Unknown DSAP 0x%02x", dsap)));
 349                 }
 350         }
 351
 352         if (is_u) {
 353                 ND_PRINT((ndo, "Unnumbered, %s, Flags [%s], length %u",
 354                        tok2str(llc_cmd_values, "%02x", LLC_U_CMD(control)),
 355                        tok2str(llc_flag_values,"?",(ssap_field & LLC_GSAP) | (control & LLC_U_POLL)),
 356                        length + hdrlen));
 357
 358                 if ((control & ~LLC_U_POLL) == LLC_XID) {
 359                         if (*p == LLC_XID_FI) {
 360                                 ND_PRINT((ndo, ": %02x %02x", p[1], p[2]));
 361                                 return (hdrlen);
 362                         }
 363                 }
 364         } else {
 365                 if ((control & LLC_S_FMT) == LLC_S_FMT) {
 366                         ND_PRINT((ndo, "Supervisory, %s, rcv seq %u, Flags [%s], length %u",
 367                                 tok2str(llc_supervisory_values,"?",LLC_S_CMD(control)),
 368                                 LLC_IS_NR(control),
 369                                 tok2str(llc_flag_values,"?",(ssap_field & LLC_GSAP) | (control & LLC_IS_POLL)),
 370                                 length + hdrlen));
 371                         return (hdrlen);        /* no payload to print */
 372                 } else {
 373                         ND_PRINT((ndo, "Information, send seq %u, rcv seq %u, Flags [%s], length %u",
 374                                 LLC_I_NS(control),
 375                                 LLC_IS_NR(control),
 376                                 tok2str(llc_flag_values,"?",(ssap_field & LLC_GSAP) | (control & LLC_IS_POLL)),
 377                                 length + hdrlen));
 378                 }
 379         }
 380         return (-hdrlen);
 381 }
 382
 383 static const struct tok *
 384 oui_to_struct_tok(uint32_t orgcode)
 385 {
 386         const struct tok *tok = null_values;
 387         const struct oui_tok *otp;
 388
 389         for (otp = &oui_to_tok[0]; otp->tok != NULL; otp++) {
 390                 if (otp->oui == orgcode) {
 391                         tok = otp->tok;
 392                         break;
 393                 }
 394         }
 395         return (tok);
 396 }
 397
 398 int
 399 snap_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen,
 400         const u_char *esrc, const u_char *edst, u_int bridge_pad)
 401 {
 402         uint32_t orgcode;
 403         register u_short et;
 404         register int ret;
 405
 406         ND_TCHECK2(*p, 5);
 407         if (caplen < 5 || length < 5)
 408                 goto trunc;
 409         orgcode = EXTRACT_24BITS(p);
 410         et = EXTRACT_16BITS(p + 3);
 411
 412         if (ndo->ndo_eflag) {
 413                 /*
 414                  * Somebody's already printed the MAC addresses, if there
 415                  * are any, so just print the SNAP header, not the MAC
 416                  * addresses.
 417                  */
 418                 ND_PRINT((ndo, "oui %s (0x%06x), %s %s (0x%04x), length %u: ",
 419                      tok2str(oui_values, "Unknown", orgcode),
 420                      orgcode,
 421                      (orgcode == 0x000000 ? "ethertype" : "pid"),
 422                      tok2str(oui_to_struct_tok(orgcode), "Unknown", et),
 423                      et, length - 5));
 424         }
 425         p += 5;
 426         length -= 5;
 427         caplen -= 5;
 428
 429         switch (orgcode) {
 430         case OUI_ENCAP_ETHER:
 431         case OUI_CISCO_90:
 432                 /*
 433                  * This is an encapsulated Ethernet packet,
 434                  * or a packet bridged by some piece of
 435                  * Cisco hardware; the protocol ID is
 436                  * an Ethernet protocol type.
 437                  */
 438                 ret = ethertype_print(ndo, et, p, length, caplen);
 439                 if (ret)
 440                         return (ret);
 441                 break;
 442
 443         case OUI_APPLETALK:
 444                 if (et == ETHERTYPE_ATALK) {
 445                         /*
 446                          * No, I have no idea why Apple used one
 447                          * of their own OUIs, rather than
 448                          * 0x000000, and an Ethernet packet
 449                          * type, for Appletalk data packets,
 450                          * but used 0x000000 and an Ethernet
 451                          * packet type for AARP packets.
 452                          */
 453                         ret = ethertype_print(ndo, et, p, length, caplen);
 454                         if (ret)
 455                                 return (ret);
 456                 }
 457                 break;
 458
 459         case OUI_CISCO:
 460                 switch (et) {
 461                 case PID_CISCO_CDP:
 462                         cdp_print(ndo, p, length, caplen);
 463                         return (1);
 464                 case PID_CISCO_DTP:
 465                         dtp_print(ndo, p, length);
 466                         return (1);
 467                 case PID_CISCO_UDLD:
 468                         udld_print(ndo, p, length);
 469                         return (1);
 470                 case PID_CISCO_VTP:
 471                         vtp_print(ndo, p, length);
 472                         return (1);
 473                 case PID_CISCO_PVST:
 474                 case PID_CISCO_VLANBRIDGE:
 475                         stp_print(ndo, p, length);
 476                         return (1);
 477                 default:
 478                         break;
 479                 }
 480                 break;
 481
 482         case OUI_RFC2684:
 483                 switch (et) {
 484
 485                 case PID_RFC2684_ETH_FCS:
 486                 case PID_RFC2684_ETH_NOFCS:
 487                         /*
 488                          * XXX - remove the last two bytes for
 489                          * PID_RFC2684_ETH_FCS?
 490                          */
 491                         /*
 492                          * Skip the padding.
 493                          */
 494                         ND_TCHECK2(*p, bridge_pad);
 495                         caplen -= bridge_pad;
 496                         length -= bridge_pad;
 497                         p += bridge_pad;
 498
 499                         /*
 500                          * What remains is an Ethernet packet.
 501                          */
 502                         ether_print(ndo, p, length, caplen, NULL, NULL);
 503                         return (1);
 504
 505                 case PID_RFC2684_802_5_FCS:
 506                 case PID_RFC2684_802_5_NOFCS:
 507                         /*
 508                          * XXX - remove the last two bytes for
 509                          * PID_RFC2684_ETH_FCS?
 510                          */
 511                         /*
 512                          * Skip the padding, but not the Access
 513                          * Control field.
 514                          */
 515                         ND_TCHECK2(*p, bridge_pad);
 516                         caplen -= bridge_pad;
 517                         length -= bridge_pad;
 518                         p += bridge_pad;
 519
 520                         /*
 521                          * What remains is an 802.5 Token Ring
 522                          * packet.
 523                          */
 524                         token_print(ndo, p, length, caplen);
 525                         return (1);
 526
 527                 case PID_RFC2684_FDDI_FCS:
 528                 case PID_RFC2684_FDDI_NOFCS:
 529                         /*
 530                          * XXX - remove the last two bytes for
 531                          * PID_RFC2684_ETH_FCS?
 532                          */
 533                         /*
 534                          * Skip the padding.
 535                          */
 536                         ND_TCHECK2(*p, bridge_pad + 1);
 537                         caplen -= bridge_pad + 1;
 538                         length -= bridge_pad + 1;
 539                         p += bridge_pad + 1;
 540
 541                         /*
 542                          * What remains is an FDDI packet.
 543                          */
 544                         fddi_print(ndo, p, length, caplen);
 545                         return (1);
 546
 547                 case PID_RFC2684_BPDU:
 548                         stp_print(ndo, p, length);
 549                         return (1);
 550                 }
 551         }
 552         if (!ndo->ndo_eflag) {
 553                 /*
 554                  * Nobody printed the MAC addresses, so print them, if
 555                  * we have any.
 556                  */
 557                 if (esrc != NULL && edst != NULL) {
 558                         ND_PRINT((ndo, "%s > %s ",
 559                                 etheraddr_string(ndo, esrc),
 560                                 etheraddr_string(ndo, edst)));
 561                 }
 562                 /*
 563                  * Print the SNAP header, but if the OUI is 000000, don't
 564                  * bother printing it, and report the PID as being an
 565                  * ethertype.
 566                  */
 567                 if (orgcode == 0x000000) {
 568                         ND_PRINT((ndo, "SNAP, ethertype %s (0x%04x), length %u: ",
 569                              tok2str(ethertype_values, "Unknown", et),
 570                              et, length));
 571                 } else {
 572                         ND_PRINT((ndo, "SNAP, oui %s (0x%06x), pid %s (0x%04x), length %u: ",
 573                              tok2str(oui_values, "Unknown", orgcode),
 574                              orgcode,
 575                              tok2str(oui_to_struct_tok(orgcode), "Unknown", et),
 576                              et, length));
 577                 }
 578         }
 579         return (0);
 580
 581 trunc:
 582         ND_PRINT((ndo, "[|snap]"));
 583         return (1);
 584 }
 585
 586
 587 /*
 588  * Local Variables:
 589  * c-style: whitesmith
 590  * c-basic-offset: 8
 591  * End:
 592  */