packet-llc.c

   1 /* packet-llc.c
   2  * Routines for IEEE 802.2 LLC layer
   3  * Gilbert Ramirez <gram@alumni.rice.edu>
   4  *
   5  * $Id: packet-llc.c,v 1.105 2002/12/10 02:49:31 guy Exp $
   6  *
   7  * Ethereal - Network traffic analyzer
   8  * By Gerald Combs <gerald@ethereal.com>
   9  * Copyright 1998 Gerald Combs
  10  *
  11  * This program is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU General Public License
  13  * as published by the Free Software Foundation; either version 2
  14  * of the License, or (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  24  */
  25
  26 #ifdef HAVE_CONFIG_H
  27 # include "config.h"
  28 #endif
  29
  30 #include <glib.h>
  31 #include <epan/packet.h>
  32 #include "oui.h"
  33 #include "xdlc.h"
  34 #include "etypes.h"
  35 #include "llcsaps.h"
  36 #include "bridged_pids.h"
  37 #include "ppptypes.h"
  38 #include "packet-fc.h"
  39 #include "packet-ip.h"
  40 #include "packet-ipx.h"
  41 #include "packet-netbios.h"
  42 #include <epan/sna-utils.h>
  43
  44 #include "packet-llc.h"
  45
  46 #define UDP_PORT_LLC1   12000
  47 #define UDP_PORT_LLC2   12001
  48 #define UDP_PORT_LLC3   12002
  49 #define UDP_PORT_LLC4   12003
  50 #define UDP_PORT_LLC5   12004
  51
  52 static int proto_llc = -1;
  53 static int hf_llc_dsap = -1;
  54 static int hf_llc_ssap = -1;
  55 static int hf_llc_dsap_ig = -1;
  56 static int hf_llc_ssap_cr = -1;
  57 static int hf_llc_ctrl = -1;
  58 static int hf_llc_type = -1;
  59 static int hf_llc_oui = -1;
  60 static int hf_llc_pid = -1;
  61
  62 static gint ett_llc = -1;
  63 static gint ett_llc_ctrl = -1;
  64
  65 static dissector_table_t subdissector_table;
  66 static dissector_table_t cisco_subdissector_table;
  67
  68 static dissector_handle_t bpdu_handle;
  69 static dissector_handle_t eth_handle;
  70 static dissector_handle_t fddi_handle;
  71 static dissector_handle_t tr_handle;
  72 static dissector_handle_t data_handle;
  73
  74 /*
  75  * Group/Individual bit, in the DSAP.
  76  */
  77 #define DSAP_GI_BIT     0x01
  78
  79 /*
  80  * Command/Response bit, in the SSAP.
  81  *
  82  * The low-order bit of the SSAP apparently determines whether this
  83  * is a request or a response.  (RFC 1390, "Transmission of IP and
  84  * ARP over FDDI Networks", says
  85  *
  86  *      Command frames are identified by having the low order
  87  *      bit of the SSAP address reset to zero.  Response frames
  88  *      have the low order bit of the SSAP address set to one.
  89  *
  90  * and a page I've seen seems to imply that's part of 802.2.)
  91  */
  92 #define SSAP_CR_BIT     0x01
  93
  94 /*
  95  * Mask to extrace the SAP number from the DSAP or the SSAP.
  96  */
  97 #define SAP_MASK        0xFE
  98
  99 /*
 100  * These are for SSAP and DSAP, wth last bit always zero.
 101  * XXX - some DSAPs come in separate "individual" and "group" versions,
 102  * with the last bit 0 and 1, respectively (e.g., LLC Sub-layer Management,
 103  * IBM SNA Path Control, IBM Net Management), but, whilst 0xFE is
 104  * the ISO Network Layer Protocol, 0xFF is the Global LSAP.
 105  */
 106 const value_string sap_vals[] = {
 107         { SAP_NULL,           "NULL LSAP" },
 108         { SAP_LLC_SLMGMT,     "LLC Sub-Layer Management" },
 109         { SAP_SNA_PATHCTRL,   "SNA Path Control" },
 110         { SAP_IP,             "TCP/IP" },
 111         { SAP_SNA1,           "SNA" },
 112         { SAP_SNA2,           "SNA" },
 113         { SAP_PROWAY_NM_INIT, "PROWAY (IEC955) Network Management and Initialization" },
 114         { SAP_TI,             "Texas Instruments" },
 115         { SAP_BPDU,           "Spanning Tree BPDU" },
 116         { SAP_RS511,          "EIA RS-511 Manufacturing Message Service" },
 117         { SAP_X25,            "ISO 8208 (X.25 over 802.2)" },
 118         /*
 119          * XXX - setting the group bit of SAP_X25 make 0x7F; is this just
 120          * a group version of that?
 121          */
 122         { 0x7F,               "ISO 802.2" },
 123         { SAP_XNS,            "XNS" },
 124         { SAP_BACNET,         "BACnet" },
 125         { SAP_NESTAR,         "Nestar" },
 126         { SAP_PROWAY_ASLM,    "PROWAY (IEC955) Active Station List Maintenance" },
 127         { SAP_ARP,            "ARP" },  /* XXX - hand to "dissect_arp()"? */
 128         { SAP_SNAP,           "SNAP" },
 129         { SAP_VINES1,         "Banyan Vines" },
 130         { SAP_VINES2,         "Banyan Vines" },
 131         { SAP_NETWARE,        "NetWare" },
 132         { SAP_NETBIOS,        "NetBIOS" },
 133         { SAP_IBMNM,          "IBM Net Management" },
 134         { SAP_RPL1,           "Remote Program Load" },
 135         { SAP_UB,             "Ungermann-Bass" },
 136         { SAP_RPL2,           "Remote Program Load" },
 137         { SAP_OSINL,          "ISO Network Layer" },
 138         { SAP_GLOBAL,         "Global LSAP" },
 139         { 0x00,               NULL }
 140 };
 141
 142 /*
 143  * See
 144  *
 145  * http://www.cisco.com/univercd/cc/td/doc/product/lan/trsrb/vlan.htm
 146  *
 147  * for the PIDs for VTP and DRiP that go with an OUI of OUI_CISCO.
 148  */
 149 const value_string oui_vals[] = {
 150         { OUI_ENCAP_ETHER, "Encapsulated Ethernet" },
 151 /*
 152 http://www.cisco.com/univercd/cc/td/doc/product/software/ios113ed/113ed_cr/ibm_r/brprt1/brsrb.htm
 153 */
 154         { OUI_CISCO,       "Cisco" },
 155         { OUI_CISCO_90,    "Cisco IOS 9.0 Compatible" },
 156         { OUI_BRIDGED,     "Frame Relay or ATM bridged frames" },
 157                                 /* RFC 2427, RFC 2684 */
 158         { OUI_ATM_FORUM,   "ATM Forum" },
 159         { OUI_CABLE_BPDU,  "DOCSIS Spanning Tree" }, /* DOCSIS spanning tree BPDU */
 160         { OUI_APPLE_ATALK, "Apple (AppleTalk)" },
 161         { 0,               NULL }
 162 };
 163
 164 void
 165 capture_llc(const guchar *pd, int offset, int len, packet_counts *ld) {
 166
 167         int             is_snap;
 168         guint16         control;
 169         int             llc_header_len;
 170         guint32         oui;
 171         guint16         etype;
 172
 173         if (!BYTES_ARE_IN_FRAME(offset, len, 2)) {
 174                 ld->other++;
 175                 return;
 176         }
 177         is_snap = (pd[offset] == SAP_SNAP) && (pd[offset+1] == SAP_SNAP);
 178         llc_header_len = 2;     /* DSAP + SSAP */
 179
 180         /*
 181          * XXX - the page referred to in the comment above about the
 182          * Command/Response bit also implies that LLC Type 2 always
 183          * uses extended operation, so we don't need to determine
 184          * whether it's basic or extended operation; is that the case?
 185          */
 186         control = get_xdlc_control(pd, offset+2, pd[offset+1] & SSAP_CR_BIT);
 187         llc_header_len += XDLC_CONTROL_LEN(control, TRUE);
 188         if (is_snap)
 189                 llc_header_len += 5;    /* 3 bytes of OUI, 2 bytes of protocol ID */
 190         if (!BYTES_ARE_IN_FRAME(offset, len, llc_header_len)) {
 191                 ld->other++;
 192                 return;
 193         }
 194
 195         if (is_snap) {
 196                 oui = pd[offset+3] << 16 | pd[offset+4] << 8 | pd[offset+5];
 197                 if (XDLC_IS_INFORMATION(control)) {
 198                         etype = pntohs(&pd[offset+6]);
 199                         switch (oui) {
 200
 201                         case OUI_ENCAP_ETHER:
 202                         case OUI_CISCO_90:
 203                         case OUI_APPLE_ATALK:
 204                                 /* No, I have no idea why Apple used
 205                                    one of their own OUIs, rather than
 206                                    OUI_ENCAP_ETHER, and an Ethernet
 207                                    packet type as protocol ID, for
 208                                    AppleTalk data packets - but used
 209                                    OUI_ENCAP_ETHER and an Ethernet
 210                                    packet type for AARP packets. */
 211                                 capture_ethertype(etype, pd, offset+8, len,
 212                                     ld);
 213                                 break;
 214                         case OUI_CISCO:
 215                                 capture_ethertype(etype, pd, offset + 8, len,
 216                                     ld);
 217                                 break;
 218                         default:
 219                                 ld->other++;
 220                                 break;
 221                         }
 222                 }
 223         }
 224         else {
 225                 /* non-SNAP */
 226                 if (XDLC_IS_INFORMATION(control)) {
 227                         switch (pd[offset]) {
 228
 229                         case SAP_IP:
 230                                 capture_ip(pd, offset + llc_header_len, len,
 231                                     ld);
 232                                 break;
 233
 234                         case SAP_NETWARE:
 235                                 capture_ipx(ld);
 236                                 break;
 237
 238                         case SAP_NETBIOS:
 239                                 capture_netbios(ld);
 240                                 break;
 241
 242                         default:
 243                                 ld->other++;
 244                                 break;
 245                         }
 246                 }
 247         }
 248 }
 249
 250 static void
 251 dissect_llc(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 252 {
 253         proto_tree      *llc_tree = NULL;
 254         proto_item      *ti = NULL;
 255         int             is_snap;
 256         guint16         control;
 257         int             llc_header_len;
 258         guint8          dsap, ssap;
 259         tvbuff_t        *next_tvb;
 260
 261         if (check_col(pinfo->cinfo, COL_PROTOCOL)) {
 262                 col_set_str(pinfo->cinfo, COL_PROTOCOL, "LLC");
 263         }
 264         if (check_col(pinfo->cinfo, COL_INFO)) {
 265                 col_clear(pinfo->cinfo, COL_INFO);
 266         }
 267
 268         dsap = tvb_get_guint8(tvb, 0);
 269         if (tree) {
 270                 ti = proto_tree_add_item(tree, proto_llc, tvb, 0, -1, FALSE);
 271                 llc_tree = proto_item_add_subtree(ti, ett_llc);
 272                 proto_tree_add_uint(llc_tree, hf_llc_dsap, tvb, 0,
 273                         1, dsap & SAP_MASK);
 274                 proto_tree_add_boolean(llc_tree, hf_llc_dsap_ig, tvb, 0,
 275                         1, dsap & DSAP_GI_BIT);
 276         } else
 277                 llc_tree = NULL;
 278
 279         ssap = tvb_get_guint8(tvb, 1);
 280         if (tree) {
 281                 proto_tree_add_uint(llc_tree, hf_llc_ssap, tvb, 1,
 282                         1, ssap & SAP_MASK);
 283                 proto_tree_add_boolean(llc_tree, hf_llc_ssap_cr, tvb, 1,
 284                         1, ssap & SSAP_CR_BIT);
 285         } else
 286                 llc_tree = NULL;
 287
 288         is_snap = (dsap == SAP_SNAP) && (ssap == SAP_SNAP);
 289         llc_header_len = 2;     /* DSAP + SSAP */
 290
 291         /*
 292          * XXX - the page referred to in the comment above about the
 293          * Command/Response bit also implies that LLC Type 2 always
 294          * uses extended operation, so we don't need to determine
 295          * whether it's basic or extended operation; is that the case?
 296          */
 297         control = dissect_xdlc_control(tvb, 2, pinfo, llc_tree,
 298                                 hf_llc_ctrl, ett_llc_ctrl,
 299                                 ssap & SSAP_CR_BIT, TRUE);
 300         llc_header_len += XDLC_CONTROL_LEN(control, TRUE);
 301         if (is_snap)
 302                 llc_header_len += 5;    /* 3 bytes of OUI, 2 bytes of protocol ID */
 303
 304         if (tree)
 305                 proto_item_set_len(ti, llc_header_len);
 306
 307         if (is_snap) {
 308                 dissect_snap(tvb, 3, pinfo, tree, llc_tree, control,
 309                     hf_llc_oui, hf_llc_type, hf_llc_pid, 2);
 310         }
 311         else {
 312                 if (check_col(pinfo->cinfo, COL_INFO)) {
 313                         col_append_fstr(pinfo->cinfo, COL_INFO,
 314                             "; DSAP %s %s, SSAP %s %s",
 315                             val_to_str(dsap & SAP_MASK, sap_vals, "%02x"),
 316                             dsap & DSAP_GI_BIT ?
 317                               "Group" : "Individual",
 318                             val_to_str(ssap & SAP_MASK, sap_vals, "%02x"),
 319                             ssap & SSAP_CR_BIT ?
 320                               "Response" : "Command"
 321                         );
 322                 }
 323
 324                 next_tvb = tvb_new_subset(tvb, llc_header_len, -1, -1);
 325                 if (XDLC_IS_INFORMATION(control)) {
 326                         /* non-SNAP */
 327                         /* do lookup with the subdissector table */
 328                         if (!dissector_try_port(subdissector_table, dsap,
 329                             next_tvb, pinfo, tree)) {
 330                                 call_dissector(data_handle,next_tvb, pinfo, tree);
 331                         }
 332                 } else {
 333                         call_dissector(data_handle,next_tvb, pinfo, tree);
 334                 }
 335         }
 336 }
 337
 338 /*
 339  * Dissect SNAP header; used elsewhere, e.g. in the Frame Relay dissector.
 340  */
 341 void
 342 dissect_snap(tvbuff_t *tvb, int offset, packet_info *pinfo, proto_tree *tree,
 343     proto_tree *snap_tree, int control, int hf_oui, int hf_type, int hf_pid,
 344     int bridge_pad)
 345 {
 346         guint32         oui;
 347         guint16         etype;
 348         tvbuff_t        *next_tvb;
 349
 350         oui =   tvb_get_ntoh24(tvb, offset);
 351         etype = tvb_get_ntohs(tvb, offset+3);
 352
 353         if (check_col(pinfo->cinfo, COL_INFO)) {
 354                 col_append_fstr(pinfo->cinfo, COL_INFO,
 355                     "; SNAP, OUI 0x%06X (%s), PID 0x%04X",
 356                     oui, val_to_str(oui, oui_vals, "Unknown"), etype);
 357         }
 358         if (tree) {
 359                 proto_tree_add_uint(snap_tree, hf_oui, tvb, offset, 3, oui);
 360         }
 361
 362         switch (oui) {
 363
 364         case OUI_ENCAP_ETHER:
 365         case OUI_CISCO_90:
 366         case OUI_APPLE_ATALK:
 367                 /* No, I have no idea why Apple used
 368                    one of their own OUIs, rather than
 369                    OUI_ENCAP_ETHER, and an Ethernet
 370                    packet type as protocol ID, for
 371                    AppleTalk data packets - but used
 372                    OUI_ENCAP_ETHER and an Ethernet
 373                    packet type for AARP packets. */
 374                 if (XDLC_IS_INFORMATION(control)) {
 375                         ethertype(etype, tvb, offset+5,
 376                             pinfo, tree, snap_tree, hf_type, -1);
 377                 } else {
 378                         next_tvb = tvb_new_subset(tvb, offset+5, -1, -1);
 379                         call_dissector(data_handle,next_tvb, pinfo, tree);
 380                 }
 381                 break;
 382
 383         case OUI_BRIDGED:
 384                 /*
 385                  * MAC frames bridged over ATM (RFC 2684) or Frame Relay
 386                  * (RFC 2427).
 387                  *
 388                  * We have to figure out how much padding to put
 389                  * into the frame.  We were handed a "bridge_pad"
 390                  * argument which should be 0 for Frame Relay and
 391                  * 2 for ATM; we add to that the amount of padding
 392                  * common to both bridging types.
 393                  */
 394                 if (tree) {
 395                         proto_tree_add_uint(snap_tree, hf_pid, tvb, offset+3, 2,
 396                             etype);
 397                 }
 398
 399                 switch (etype) {
 400
 401                 case BPID_ETH_WITH_FCS:
 402                 case BPID_ETH_WITHOUT_FCS:
 403                         next_tvb = tvb_new_subset(tvb, offset+5+bridge_pad,
 404                             -1, -1);
 405                         call_dissector(eth_handle, next_tvb, pinfo, tree);
 406                         break;
 407
 408                 case BPID_802_5_WITH_FCS:
 409                 case BPID_802_5_WITHOUT_FCS:
 410                         /*
 411                          * We treat the last padding byte as the Access
 412                          * Control byte, as that's what the Token
 413                          * Ring dissector expects the first byte to
 414                          * be.
 415                          */
 416                         next_tvb = tvb_new_subset(tvb, offset+5+bridge_pad,
 417                             -1, -1);
 418                         call_dissector(tr_handle, next_tvb, pinfo, tree);
 419                         break;
 420
 421                 case BPID_FDDI_WITH_FCS:
 422                 case BPID_FDDI_WITHOUT_FCS:
 423                         next_tvb = tvb_new_subset(tvb, offset+5+1+bridge_pad,
 424                             -1, -1);
 425                         call_dissector(fddi_handle, next_tvb, pinfo, tree);
 426                         break;
 427
 428                 case BPID_BPDU:
 429                         next_tvb = tvb_new_subset(tvb, offset+5, -1, -1);
 430                         call_dissector(bpdu_handle, next_tvb, pinfo, tree);
 431                         break;
 432
 433                 default:
 434                         next_tvb = tvb_new_subset(tvb, offset+5, -1, -1);
 435                         call_dissector(data_handle,next_tvb, pinfo, tree);
 436                         break;
 437                 }
 438                 break;
 439
 440         case OUI_CISCO:
 441                 /* So are all CDP packets LLC packets
 442                    with an OUI of OUI_CISCO and a
 443                    protocol ID of 0x2000, or
 444                    are some of them raw or encapsulated
 445                    Ethernet? */
 446                 if (tree) {
 447                         proto_tree_add_uint(snap_tree, hf_pid, tvb, offset+3, 2,
 448                             etype);
 449                 }
 450                 next_tvb = tvb_new_subset(tvb, offset+5, -1, -1);
 451                 if (XDLC_IS_INFORMATION(control)) {
 452                         /* do lookup with the subdissector table */
 453                         /* for future reference, 0x0102 is Cisco DRIP */
 454                         if (!dissector_try_port(cisco_subdissector_table,
 455                             etype, next_tvb, pinfo, tree))
 456                                 call_dissector(data_handle,next_tvb, pinfo, tree);
 457                 } else
 458                         call_dissector(data_handle,next_tvb, pinfo, tree);
 459                 break;
 460
 461         case OUI_CABLE_BPDU:    /* DOCSIS cable modem spanning tree BPDU */
 462                 if (tree) {
 463                         proto_tree_add_uint(snap_tree, hf_pid, tvb, offset+3, 2,
 464                             etype);
 465                 }
 466                 next_tvb = tvb_new_subset(tvb, offset+5, -1, -1);
 467                 call_dissector(bpdu_handle, next_tvb, pinfo, tree);
 468                 break;
 469
 470         default:
 471                 if (tree) {
 472                         proto_tree_add_uint(snap_tree, hf_pid, tvb, offset+3, 2,
 473                             etype);
 474                 }
 475                 next_tvb = tvb_new_subset(tvb, offset+5, -1, -1);
 476                 call_dissector(data_handle,next_tvb, pinfo, tree);
 477                 break;
 478         }
 479 }
 480
 481 void
 482 proto_register_llc(void)
 483 {
 484         static struct true_false_string ig_bit = { "Group", "Individual" };
 485         static struct true_false_string cr_bit = { "Response", "Command" };
 486
 487         static hf_register_info hf[] = {
 488                 { &hf_llc_dsap,
 489                 { "DSAP",       "llc.dsap", FT_UINT8, BASE_HEX,
 490                         VALS(sap_vals), 0x0, "", HFILL }},
 491
 492                 { &hf_llc_dsap_ig,
 493                 { "IG Bit",     "llc.dsap.ig", FT_BOOLEAN, BASE_HEX,
 494                         &ig_bit, 0x0, "Individual/Group", HFILL }},
 495
 496                 { &hf_llc_ssap,
 497                 { "SSAP", "llc.ssap", FT_UINT8, BASE_HEX,
 498                         VALS(sap_vals), 0x0, "", HFILL }},
 499
 500                 { &hf_llc_ssap_cr,
 501                 { "CR Bit", "llc.ssap.cr", FT_BOOLEAN, BASE_HEX,
 502                         &cr_bit, 0x0, "Command/Response", HFILL }},
 503
 504                 { &hf_llc_ctrl,
 505                 { "Control", "llc.control", FT_UINT16, BASE_HEX,
 506                         NULL, 0x0, "", HFILL }},
 507
 508                 /* registered here but handled in ethertype.c */
 509                 { &hf_llc_type,
 510                 { "Type", "llc.type", FT_UINT16, BASE_HEX,
 511                         VALS(etype_vals), 0x0, "", HFILL }},
 512
 513                 { &hf_llc_oui,
 514                 { "Organization Code",  "llc.oui", FT_UINT24, BASE_HEX,
 515                         VALS(oui_vals), 0x0, "", HFILL }},
 516
 517                 { &hf_llc_pid,
 518                 { "Protocol ID", "llc.pid", FT_UINT16, BASE_HEX,
 519                         NULL, 0x0, "", HFILL }}
 520         };
 521         static gint *ett[] = {
 522                 &ett_llc,
 523                 &ett_llc_ctrl,
 524         };
 525
 526         proto_llc = proto_register_protocol("Logical-Link Control", "LLC", "llc");
 527         proto_register_field_array(proto_llc, hf, array_length(hf));
 528         proto_register_subtree_array(ett, array_length(ett));
 529
 530 /* subdissector code */
 531         subdissector_table = register_dissector_table("llc.dsap",
 532           "LLC SAP", FT_UINT8, BASE_HEX);
 533         cisco_subdissector_table = register_dissector_table("llc.cisco_pid",
 534           "Cisco OUI PID", FT_UINT16, BASE_HEX);
 535
 536         register_dissector("llc", dissect_llc, proto_llc);
 537 }
 538
 539 void
 540 proto_reg_handoff_llc(void)
 541 {
 542         dissector_handle_t llc_handle;
 543
 544         /*
 545          * Get handles for the BPDU, Ethernet, FDDI, and Token Ring
 546          * dissectors.
 547          */
 548         bpdu_handle = find_dissector("bpdu");
 549         eth_handle = find_dissector("eth");
 550         fddi_handle = find_dissector("fddi");
 551         tr_handle = find_dissector("tr");
 552         data_handle = find_dissector("data");
 553
 554         llc_handle = find_dissector("llc");
 555         dissector_add("wtap_encap", WTAP_ENCAP_ATM_RFC1483, llc_handle);
 556         /* RFC 2043 */
 557         dissector_add("ppp.protocol", PPP_LLC, llc_handle);
 558         /* RFC 2353 */
 559         dissector_add("udp.port", UDP_PORT_LLC1, llc_handle);
 560         dissector_add("udp.port", UDP_PORT_LLC2, llc_handle);
 561         dissector_add("udp.port", UDP_PORT_LLC3, llc_handle);
 562         dissector_add("udp.port", UDP_PORT_LLC4, llc_handle);
 563         dissector_add("udp.port", UDP_PORT_LLC5, llc_handle);
 564         /* IP-over-FC when we have the full FC frame */
 565         dissector_add("fc.ftype", FC_FTYPE_IP, llc_handle);
 566 }