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 /* \summary: IEEE 802.2 LLC printer */
  26
  27 #include <config.h>
  28
  29 #include "netdissect-stdinc.h"
  30
  31 #include "netdissect.h"
  32 #include "addrtoname.h"
  33 #include "extract.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 struct lladdr_info *src, const struct lladdr_info *dst)
 150 {
 151         uint8_t dsap_field, dsap, ssap_field, ssap;
 152         uint16_t control;
 153         int hdrlen;
 154         int is_u;
 155
 156         ndo->ndo_protocol = "llc";
 157         if (caplen < 3) {
 158                 nd_print_trunc(ndo);
 159                 ND_DEFAULTPRINT((const u_char *)p, caplen);
 160                 return (caplen);
 161         }
 162         if (length < 3) {
 163                 nd_print_trunc(ndo);
 164                 ND_DEFAULTPRINT((const u_char *)p, caplen);
 165                 return (length);
 166         }
 167
 168         dsap_field = GET_U_1(p);
 169         ssap_field = GET_U_1(p + 1);
 170
 171         /*
 172          * OK, what type of LLC frame is this?  The length
 173          * of the control field depends on that - I frames
 174          * have a two-byte control field, and U frames have
 175          * a one-byte control field.
 176          */
 177         control = GET_U_1(p + 2);
 178         if ((control & LLC_U_FMT) == LLC_U_FMT) {
 179                 /*
 180                  * U frame.
 181                  */
 182                 is_u = 1;
 183                 hdrlen = 3;     /* DSAP, SSAP, 1-byte control field */
 184         } else {
 185                 /*
 186                  * The control field in I and S frames is
 187                  * 2 bytes...
 188                  */
 189                 if (caplen < 4) {
 190                         nd_print_trunc(ndo);
 191                         ND_DEFAULTPRINT((const u_char *)p, caplen);
 192                         return (caplen);
 193                 }
 194                 if (length < 4) {
 195                         nd_print_trunc(ndo);
 196                         ND_DEFAULTPRINT((const u_char *)p, caplen);
 197                         return (length);
 198                 }
 199
 200                 /*
 201                  * ...and is little-endian.
 202                  */
 203                 control = GET_LE_U_2(p + 2);
 204                 is_u = 0;
 205                 hdrlen = 4;     /* DSAP, SSAP, 2-byte control field */
 206         }
 207
 208         if (ssap_field == LLCSAP_GLOBAL && dsap_field == LLCSAP_GLOBAL) {
 209                 /*
 210                  * This is an Ethernet_802.3 IPX frame; it has an
 211                  * 802.3 header (i.e., an Ethernet header where the
 212                  * type/length field is <= MAX_ETHERNET_LENGTH_VAL,
 213                  * i.e. it's a length field, not a type field), but
 214                  * has no 802.2 header - the IPX packet starts right
 215                  * after the Ethernet header, with a signature of two
 216                  * bytes of 0xFF (which is LLCSAP_GLOBAL).
 217                  *
 218                  * (It might also have been an Ethernet_802.3 IPX at
 219                  * one time, but got bridged onto another network,
 220                  * such as an 802.11 network; this has appeared in at
 221                  * least one capture file.)
 222                  */
 223
 224             if (ndo->ndo_eflag)
 225                 ND_PRINT("IPX 802.3: ");
 226
 227             ipx_print(ndo, p, length);
 228             return (0);         /* no LLC header */
 229         }
 230
 231         dsap = dsap_field & ~LLC_IG;
 232         ssap = ssap_field & ~LLC_GSAP;
 233
 234         if (ndo->ndo_eflag) {
 235                 ND_PRINT("LLC, dsap %s (0x%02x) %s, ssap %s (0x%02x) %s",
 236                        tok2str(llc_values, "Unknown", dsap),
 237                        dsap,
 238                        tok2str(llc_ig_flag_values, "Unknown", dsap_field & LLC_IG),
 239                        tok2str(llc_values, "Unknown", ssap),
 240                        ssap,
 241                        tok2str(llc_flag_values, "Unknown", ssap_field & LLC_GSAP));
 242
 243                 if (is_u) {
 244                         ND_PRINT(", ctrl 0x%02x: ", control);
 245                 } else {
 246                         ND_PRINT(", ctrl 0x%04x: ", control);
 247                 }
 248         }
 249
 250         /*
 251          * Skip LLC header.
 252          */
 253         p += hdrlen;
 254         length -= hdrlen;
 255         caplen -= hdrlen;
 256
 257         if (ssap == LLCSAP_SNAP && dsap == LLCSAP_SNAP
 258             && control == LLC_UI) {
 259                 /*
 260                  * XXX - what *is* the right bridge pad value here?
 261                  * Does anybody ever bridge one form of LAN traffic
 262                  * over a networking type that uses 802.2 LLC?
 263                  */
 264                 if (!snap_print(ndo, p, length, caplen, src, dst, 2)) {
 265                         /*
 266                          * Unknown packet type; tell our caller, by
 267                          * returning a negative value, so they
 268                          * can print the raw packet.
 269                          */
 270                         return (-(hdrlen + 5)); /* include LLC and SNAP header */
 271                 } else
 272                         return (hdrlen + 5);    /* include LLC and SNAP header */
 273         }
 274
 275         if (ssap == LLCSAP_8021D && dsap == LLCSAP_8021D &&
 276             control == LLC_UI) {
 277                 stp_print(ndo, p, length);
 278                 return (hdrlen);
 279         }
 280
 281         if (ssap == LLCSAP_IP && dsap == LLCSAP_IP &&
 282             control == LLC_UI) {
 283                 /*
 284                  * This is an RFC 948-style IP packet, with
 285                  * an 802.3 header and an 802.2 LLC header
 286                  * with the source and destination SAPs being
 287                  * the IP SAP.
 288                  */
 289                 ip_print(ndo, p, length);
 290                 return (hdrlen);
 291         }
 292
 293         if (ssap == LLCSAP_IPX && dsap == LLCSAP_IPX &&
 294             control == LLC_UI) {
 295                 /*
 296                  * This is an Ethernet_802.2 IPX frame, with an 802.3
 297                  * header and an 802.2 LLC header with the source and
 298                  * destination SAPs being the IPX SAP.
 299                  */
 300                 if (ndo->ndo_eflag)
 301                         ND_PRINT("IPX 802.2: ");
 302
 303                 ipx_print(ndo, p, length);
 304                 return (hdrlen);
 305         }
 306
 307 #ifdef ENABLE_SMB
 308         if (ssap == LLCSAP_NETBEUI && dsap == LLCSAP_NETBEUI
 309             && (!(control & LLC_S_FMT) || control == LLC_U_FMT)) {
 310                 /*
 311                  * we don't actually have a full netbeui parser yet, but the
 312                  * smb parser can handle many smb-in-netbeui packets, which
 313                  * is very useful, so we call that
 314                  *
 315                  * We don't call it for S frames, however, just I frames
 316                  * (which are frames that don't have the low-order bit,
 317                  * LLC_S_FMT, set in the first byte of the control field)
 318                  * and UI frames (whose control field is just 3, LLC_U_FMT).
 319                  */
 320                 netbeui_print(ndo, control, p, length);
 321                 return (hdrlen);
 322         }
 323 #endif
 324         if (ssap == LLCSAP_ISONS && dsap == LLCSAP_ISONS
 325             && control == LLC_UI) {
 326                 isoclns_print(ndo, p, length);
 327                 return (hdrlen);
 328         }
 329
 330         if (!ndo->ndo_eflag) {
 331                 if (ssap == dsap) {
 332                         if (src == NULL || dst == NULL)
 333                                 ND_PRINT("%s ", tok2str(llc_values, "Unknown DSAP 0x%02x", dsap));
 334                         else
 335                                 ND_PRINT("%s > %s %s ",
 336                                                 (src->addr_string)(ndo, src->addr),
 337                                                 (dst->addr_string)(ndo, dst->addr),
 338                                                 tok2str(llc_values, "Unknown DSAP 0x%02x", dsap));
 339                 } else {
 340                         if (src == NULL || dst == NULL)
 341                                 ND_PRINT("%s > %s ",
 342                                         tok2str(llc_values, "Unknown SSAP 0x%02x", ssap),
 343                                         tok2str(llc_values, "Unknown DSAP 0x%02x", dsap));
 344                         else
 345                                 ND_PRINT("%s %s > %s %s ",
 346                                         (src->addr_string)(ndo, src->addr),
 347                                         tok2str(llc_values, "Unknown SSAP 0x%02x", ssap),
 348                                         (dst->addr_string)(ndo, dst->addr),
 349                                         tok2str(llc_values, "Unknown DSAP 0x%02x", dsap));
 350                 }
 351         }
 352
 353         if (is_u) {
 354                 ND_PRINT("Unnumbered, %s, Flags [%s], length %u",
 355                        tok2str(llc_cmd_values, "%02x", LLC_U_CMD(control)),
 356                        tok2str(llc_flag_values,"?",(ssap_field & LLC_GSAP) | (control & LLC_U_POLL)),
 357                        length + hdrlen);
 358
 359                 if ((control & ~LLC_U_POLL) == LLC_XID) {
 360                         if (length == 0) {
 361                                 /*
 362                                  * XID with no payload.
 363                                  * This could, for example, be an SNA
 364                                  * "short form" XID.
 365                                  */
 366                                 return (hdrlen);
 367                         }
 368                         if (caplen < 1) {
 369                                 nd_print_trunc(ndo);
 370                                 if (caplen > 0)
 371                                         ND_DEFAULTPRINT((const u_char *)p, caplen);
 372                                 return (hdrlen);
 373                         }
 374                         if (GET_U_1(p) == LLC_XID_FI) {
 375                                 if (caplen < 3 || length < 3) {
 376                                         nd_print_trunc(ndo);
 377                                         if (caplen > 0)
 378                                                 ND_DEFAULTPRINT((const u_char *)p, caplen);
 379                                 } else
 380                                         ND_PRINT(": %02x %02x",
 381                                                   GET_U_1(p + 1),
 382                                                   GET_U_1(p + 2));
 383                                 return (hdrlen);
 384                         }
 385                 }
 386         } else {
 387                 if ((control & LLC_S_FMT) == LLC_S_FMT) {
 388                         ND_PRINT("Supervisory, %s, rcv seq %u, Flags [%s], length %u",
 389                                 tok2str(llc_supervisory_values,"?",LLC_S_CMD(control)),
 390                                 LLC_IS_NR(control),
 391                                 tok2str(llc_flag_values,"?",(ssap_field & LLC_GSAP) | (control & LLC_IS_POLL)),
 392                                 length + hdrlen);
 393                         return (hdrlen);        /* no payload to print */
 394                 } else {
 395                         ND_PRINT("Information, send seq %u, rcv seq %u, Flags [%s], length %u",
 396                                 LLC_I_NS(control),
 397                                 LLC_IS_NR(control),
 398                                 tok2str(llc_flag_values,"?",(ssap_field & LLC_GSAP) | (control & LLC_IS_POLL)),
 399                                 length + hdrlen);
 400                 }
 401         }
 402         return (-hdrlen);
 403 }
 404
 405 static const struct tok *
 406 oui_to_struct_tok(uint32_t orgcode)
 407 {
 408         const struct tok *tok = null_values;
 409         const struct oui_tok *otp;
 410
 411         for (otp = &oui_to_tok[0]; otp->tok != NULL; otp++) {
 412                 if (otp->oui == orgcode) {
 413                         tok = otp->tok;
 414                         break;
 415                 }
 416         }
 417         return (tok);
 418 }
 419
 420 int
 421 snap_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen,
 422         const struct lladdr_info *src, const struct lladdr_info *dst,
 423         u_int bridge_pad)
 424 {
 425         uint32_t orgcode;
 426         u_short et;
 427         int ret;
 428
 429         ndo->ndo_protocol = "snap";
 430         ND_TCHECK_5(p);
 431         if (caplen < 5 || length < 5)
 432                 goto trunc;
 433         orgcode = GET_BE_U_3(p);
 434         et = GET_BE_U_2(p + 3);
 435
 436         if (ndo->ndo_eflag) {
 437                 /*
 438                  * Somebody's already printed the MAC addresses, if there
 439                  * are any, so just print the SNAP header, not the MAC
 440                  * addresses.
 441                  */
 442                 ND_PRINT("oui %s (0x%06x), %s %s (0x%04x), length %u: ",
 443                      tok2str(oui_values, "Unknown", orgcode),
 444                      orgcode,
 445                      (orgcode == 0x000000 ? "ethertype" : "pid"),
 446                      tok2str(oui_to_struct_tok(orgcode), "Unknown", et),
 447                      et, length - 5);
 448         }
 449         p += 5;
 450         length -= 5;
 451         caplen -= 5;
 452
 453         switch (orgcode) {
 454         case OUI_ENCAP_ETHER:
 455         case OUI_CISCO_90:
 456                 /*
 457                  * This is an encapsulated Ethernet packet,
 458                  * or a packet bridged by some piece of
 459                  * Cisco hardware; the protocol ID is
 460                  * an Ethernet protocol type.
 461                  */
 462                 ret = ethertype_print(ndo, et, p, length, caplen, src, dst);
 463                 if (ret)
 464                         return (ret);
 465                 break;
 466
 467         case OUI_APPLETALK:
 468                 if (et == ETHERTYPE_ATALK) {
 469                         /*
 470                          * No, I have no idea why Apple used one
 471                          * of their own OUIs, rather than
 472                          * 0x000000, and an Ethernet packet
 473                          * type, for Appletalk data packets,
 474                          * but used 0x000000 and an Ethernet
 475                          * packet type for AARP packets.
 476                          */
 477                         ret = ethertype_print(ndo, et, p, length, caplen, src, dst);
 478                         if (ret)
 479                                 return (ret);
 480                 }
 481                 break;
 482
 483         case OUI_CISCO:
 484                 switch (et) {
 485                 case PID_CISCO_CDP:
 486                         cdp_print(ndo, p, length);
 487                         return (1);
 488                 case PID_CISCO_DTP:
 489                         dtp_print(ndo, p, length);
 490                         return (1);
 491                 case PID_CISCO_UDLD:
 492                         udld_print(ndo, p, length);
 493                         return (1);
 494                 case PID_CISCO_VTP:
 495                         vtp_print(ndo, p, length);
 496                         return (1);
 497                 case PID_CISCO_PVST:
 498                 case PID_CISCO_VLANBRIDGE:
 499                         stp_print(ndo, p, length);
 500                         return (1);
 501                 default:
 502                         break;
 503                 }
 504                 break;
 505
 506         case OUI_RFC2684:
 507                 switch (et) {
 508
 509                 case PID_RFC2684_ETH_FCS:
 510                 case PID_RFC2684_ETH_NOFCS:
 511                         /*
 512                          * XXX - remove the last two bytes for
 513                          * PID_RFC2684_ETH_FCS?
 514                          */
 515                         /*
 516                          * Skip the padding.
 517                          */
 518                         ND_TCHECK_LEN(p, bridge_pad);
 519                         caplen -= bridge_pad;
 520                         length -= bridge_pad;
 521                         p += bridge_pad;
 522
 523                         /*
 524                          * What remains is an Ethernet packet.
 525                          */
 526                         ether_print(ndo, p, length, caplen, NULL, NULL);
 527                         return (1);
 528
 529                 case PID_RFC2684_802_5_FCS:
 530                 case PID_RFC2684_802_5_NOFCS:
 531                         /*
 532                          * XXX - remove the last two bytes for
 533                          * PID_RFC2684_ETH_FCS?
 534                          */
 535                         /*
 536                          * Skip the padding, but not the Access
 537                          * Control field.
 538                          */
 539                         ND_TCHECK_LEN(p, bridge_pad);
 540                         caplen -= bridge_pad;
 541                         length -= bridge_pad;
 542                         p += bridge_pad;
 543
 544                         /*
 545                          * What remains is an 802.5 Token Ring
 546                          * packet.
 547                          */
 548                         token_print(ndo, p, length, caplen);
 549                         return (1);
 550
 551                 case PID_RFC2684_FDDI_FCS:
 552                 case PID_RFC2684_FDDI_NOFCS:
 553                         /*
 554                          * XXX - remove the last two bytes for
 555                          * PID_RFC2684_ETH_FCS?
 556                          */
 557                         /*
 558                          * Skip the padding.
 559                          */
 560                         ND_TCHECK_LEN(p, bridge_pad + 1);
 561                         caplen -= bridge_pad + 1;
 562                         length -= bridge_pad + 1;
 563                         p += bridge_pad + 1;
 564
 565                         /*
 566                          * What remains is an FDDI packet.
 567                          */
 568                         fddi_print(ndo, p, length, caplen);
 569                         return (1);
 570
 571                 case PID_RFC2684_BPDU:
 572                         stp_print(ndo, p, length);
 573                         return (1);
 574                 }
 575         }
 576         if (!ndo->ndo_eflag) {
 577                 /*
 578                  * Nobody printed the link-layer addresses, so print them, if
 579                  * we have any.
 580                  */
 581                 if (src != NULL && dst != NULL) {
 582                         ND_PRINT("%s > %s ",
 583                                 (src->addr_string)(ndo, src->addr),
 584                                 (dst->addr_string)(ndo, dst->addr));
 585                 }
 586                 /*
 587                  * Print the SNAP header, but if the OUI is 000000, don't
 588                  * bother printing it, and report the PID as being an
 589                  * ethertype.
 590                  */
 591                 if (orgcode == 0x000000) {
 592                         ND_PRINT("SNAP, ethertype %s (0x%04x), length %u: ",
 593                              tok2str(ethertype_values, "Unknown", et),
 594                              et, length);
 595                 } else {
 596                         ND_PRINT("SNAP, oui %s (0x%06x), pid %s (0x%04x), length %u: ",
 597                              tok2str(oui_values, "Unknown", orgcode),
 598                              orgcode,
 599                              tok2str(oui_to_struct_tok(orgcode), "Unknown", et),
 600                              et, length);
 601                 }
 602         }
 603         return (0);
 604
 605 trunc:
 606         nd_print_trunc(ndo);
 607         return (1);
 608 }