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 #ifndef lint
  26 static const char rcsid[] _U_ =
  27     "@(#) $Header: /tcpdump/master/tcpdump/print-llc.c,v 1.58 2004-05-01 10:06:00 hannes Exp $";
  28 #endif
  29
  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"                    /* must come after interface.h */
  42
  43 #include "llc.h"
  44 #include "ethertype.h"
  45
  46 static struct tok llc_values[] = {
  47         { LLCSAP_NULL,     "Null" },
  48         { LLCSAP_GLOBAL,   "Global" },
  49         { LLCSAP_8021B_I,  "802.1B I" },
  50         { LLCSAP_8021B_G,  "802.1B G" },
  51         { LLCSAP_IP,       "IP" },
  52         { LLCSAP_PROWAYNM, "ProWay NM" },
  53         { LLCSAP_8021D,    "STP" },
  54         { LLCSAP_RS511,    "RS511" },
  55         { LLCSAP_ISO8208,  "ISO8208" },
  56         { LLCSAP_PROWAY,   "ProWay" },
  57         { LLCSAP_SNAP,     "SNAP" },
  58         { LLCSAP_IPX,      "IPX" },
  59         { LLCSAP_NETBEUI,  "NetBeui" },
  60         { LLCSAP_ISONS,    "OSI" },
  61 };
  62
  63 static struct tok cmd2str[] = {
  64         { LLC_UI,       "ui" },
  65         { LLC_TEST,     "test" },
  66         { LLC_XID,      "xid" },
  67         { LLC_UA,       "ua" },
  68         { LLC_DISC,     "disc" },
  69         { LLC_DM,       "dm" },
  70         { LLC_SABME,    "sabme" },
  71         { LLC_FRMR,     "frmr" },
  72         { 0,            NULL }
  73 };
  74
  75 /*
  76  * Returns non-zero IFF it succeeds in printing the header
  77  */
  78 int
  79 llc_print(const u_char *p, u_int length, u_int caplen,
  80           const u_char *esrc, const u_char *edst, u_short *extracted_ethertype)
  81 {
  82         struct llc llc;
  83         register u_short et;
  84         u_int16_t control;
  85         register int ret;
  86
  87         if (caplen < 3) {
  88                 (void)printf("[|llc]");
  89                 default_print((u_char *)p, caplen);
  90                 return(0);
  91         }
  92
  93         /* Watch out for possible alignment problems */
  94         memcpy((char *)&llc, (char *)p, min(caplen, sizeof(llc)));
  95
  96         if (eflag)
  97           printf("LLC, dsap %s (0x%02x), ssap %s (0x%02x), cmd 0x%02x, ",
  98                  tok2str(llc_values,"Unknown",llc.dsap),
  99                  llc.dsap,
 100                  tok2str(llc_values,"Unknown",llc.ssap),
 101                  llc.ssap,
 102                  llc.llcu);
 103
 104         if (llc.ssap == LLCSAP_GLOBAL && llc.dsap == LLCSAP_GLOBAL) {
 105                 /*
 106                  * This is an Ethernet_802.3 IPX frame; it has an
 107                  * 802.3 header (i.e., an Ethernet header where the
 108                  * type/length field is <= ETHERMTU, i.e. it's a length
 109                  * field, not a type field), but has no 802.2 header -
 110                  * the IPX packet starts right after the Ethernet header,
 111                  * with a signature of two bytes of 0xFF (which is
 112                  * LLCSAP_GLOBAL).
 113                  *
 114                  * (It might also have been an Ethernet_802.3 IPX at
 115                  * one time, but got bridged onto another network,
 116                  * such as an 802.11 network; this has appeared in at
 117                  * least one capture file.)
 118                  */
 119
 120             if (eflag)
 121                 printf("IPX-802.3: ");
 122
 123             ipx_print(p, length);
 124             return (1);
 125         }
 126
 127         if (llc.ssap == LLCSAP_8021D && llc.dsap == LLCSAP_8021D) {
 128                 stp_print(p, length);
 129                 return (1);
 130         }
 131
 132         if (llc.ssap == LLCSAP_IP && llc.dsap == LLCSAP_IP) {
 133                 ip_print(p+4, length-4);
 134                 return (1);
 135         }
 136
 137         if (llc.ssap == LLCSAP_IPX && llc.dsap == LLCSAP_IPX &&
 138             llc.llcui == LLC_UI) {
 139                 /*
 140                  * This is an Ethernet_802.2 IPX frame, with an 802.3
 141                  * header and an 802.2 LLC header with the source and
 142                  * destination SAPs being the IPX SAP.
 143                  *
 144                  * Skip DSAP, LSAP, and control field.
 145                  */
 146                 printf("(NOV-802.2) ");
 147                 p += 3;
 148                 length -= 3;
 149                 caplen -= 3;
 150                 ipx_print(p, length);
 151                 return (1);
 152         }
 153
 154 #ifdef TCPDUMP_DO_SMB
 155         if (llc.ssap == LLCSAP_NETBEUI && llc.dsap == LLCSAP_NETBEUI
 156             && (!(llc.llcu & LLC_S_FMT) || llc.llcu == LLC_U_FMT)) {
 157                 /*
 158                  * we don't actually have a full netbeui parser yet, but the
 159                  * smb parser can handle many smb-in-netbeui packets, which
 160                  * is very useful, so we call that
 161                  *
 162                  * We don't call it for S frames, however, just I frames
 163                  * (which are frames that don't have the low-order bit,
 164                  * LLC_S_FMT, set in the first byte of the control field)
 165                  * and UI frames (whose control field is just 3, LLC_U_FMT).
 166                  */
 167
 168                 /*
 169                  * Skip the DSAP and LSAP.
 170                  */
 171                 p += 2;
 172                 length -= 2;
 173                 caplen -= 2;
 174
 175                 /*
 176                  * OK, what type of LLC frame is this?  The length
 177                  * of the control field depends on that - I frames
 178                  * have a two-byte control field, and U frames have
 179                  * a one-byte control field.
 180                  */
 181                 if (llc.llcu == LLC_U_FMT) {
 182                         control = llc.llcu;
 183                         p += 1;
 184                         length -= 1;
 185                         caplen -= 1;
 186                 } else {
 187                         /*
 188                          * The control field in I and S frames is
 189                          * little-endian.
 190                          */
 191                         control = EXTRACT_LE_16BITS(&llc.llcu);
 192                         p += 2;
 193                         length -= 2;
 194                         caplen -= 2;
 195                 }
 196                 netbeui_print(control, p, length);
 197                 return (1);
 198         }
 199 #endif
 200         if (llc.ssap == LLCSAP_ISONS && llc.dsap == LLCSAP_ISONS
 201             && llc.llcui == LLC_UI) {
 202                 isoclns_print(p + 3, length - 3, caplen - 3);
 203                 return (1);
 204         }
 205
 206         if (llc.ssap == LLCSAP_SNAP && llc.dsap == LLCSAP_SNAP
 207             && llc.llcui == LLC_UI) {
 208                 u_int32_t orgcode;
 209
 210                 if (caplen < sizeof(llc)) {
 211                         (void)printf("[|llc-snap]");
 212                         default_print((u_char *)p, caplen);
 213                         return (0);
 214                 }
 215
 216                 caplen -= sizeof(llc);
 217                 length -= sizeof(llc);
 218                 p += sizeof(llc);
 219
 220                 orgcode = EXTRACT_24BITS(&llc.llc_orgcode[0]);
 221                 et = EXTRACT_16BITS(&llc.llc_ethertype[0]);
 222
 223                 if (eflag)
 224                     (void)printf("oui 0x%06x, ethertype %s (0x%04x): ",
 225                                  orgcode,
 226                                  tok2str(ethertype_values,"Unknown", et),
 227                                  et);
 228
 229                 /*
 230                  * XXX - what *is* the right bridge pad value here?
 231                  * Does anybody ever bridge one form of LAN traffic
 232                  * over a networking type that uses 802.2 LLC?
 233                  */
 234                 ret = snap_print(p, length, caplen, extracted_ethertype,
 235                     orgcode, et, 2);
 236                 if (ret)
 237                         return (ret);
 238         }
 239
 240         if ((llc.ssap & ~LLC_GSAP) == llc.dsap) {
 241                 if (eflag || esrc == NULL || edst == NULL)
 242                         (void)printf("%s ", llcsap_string(llc.dsap));
 243                 else
 244                         (void)printf("%s > %s %s ",
 245                                         etheraddr_string(esrc),
 246                                         etheraddr_string(edst),
 247                                         llcsap_string(llc.dsap));
 248         } else {
 249                 if (eflag || esrc == NULL || edst == NULL)
 250                         (void)printf("%s > %s ",
 251                                 llcsap_string(llc.ssap & ~LLC_GSAP),
 252                                 llcsap_string(llc.dsap));
 253                 else
 254                         (void)printf("%s %s > %s %s ",
 255                                 etheraddr_string(esrc),
 256                                 llcsap_string(llc.ssap & ~LLC_GSAP),
 257                                 etheraddr_string(edst),
 258                                 llcsap_string(llc.dsap));
 259         }
 260
 261         if ((llc.llcu & LLC_U_FMT) == LLC_U_FMT) {
 262                 u_int16_t cmd;
 263                 const char *m;
 264                 char f;
 265
 266                 cmd = LLC_U_CMD(llc.llcu);
 267                 m = tok2str(cmd2str, "%02x", cmd);
 268                 switch ((llc.ssap & LLC_GSAP) | (llc.llcu & LLC_U_POLL)) {
 269                         case 0:                 f = 'C'; break;
 270                         case LLC_GSAP:          f = 'R'; break;
 271                         case LLC_U_POLL:        f = 'P'; break;
 272                         case LLC_GSAP|LLC_U_POLL: f = 'F'; break;
 273                         default:                f = '?'; break;
 274                 }
 275
 276                 printf("%s/%c", m, f);
 277
 278                 p += 3;
 279                 length -= 3;
 280                 caplen -= 3;
 281
 282                 if ((llc.llcu & ~LLC_U_POLL) == LLC_XID) {
 283                         if (*p == LLC_XID_FI) {
 284                                 printf(": %02x %02x", p[1], p[2]);
 285                                 p += 3;
 286                                 length -= 3;
 287                                 caplen -= 3;
 288                         }
 289                 }
 290         } else {
 291                 char f;
 292
 293                 /*
 294                  * The control field in I and S frames is little-endian.
 295                  */
 296                 control = EXTRACT_LE_16BITS(&llc.llcu);
 297                 switch ((llc.ssap & LLC_GSAP) | (control & LLC_IS_POLL)) {
 298                         case 0:                 f = 'C'; break;
 299                         case LLC_GSAP:          f = 'R'; break;
 300                         case LLC_IS_POLL:       f = 'P'; break;
 301                         case LLC_GSAP|LLC_IS_POLL: f = 'F'; break;
 302                         default:                f = '?'; break;
 303                 }
 304
 305                 if ((control & LLC_S_FMT) == LLC_S_FMT) {
 306                         static const char *llc_s[] = { "rr", "rej", "rnr", "03" };
 307                         (void)printf("%s (r=%d,%c)",
 308                                 llc_s[LLC_S_CMD(control)],
 309                                 LLC_IS_NR(control),
 310                                 f);
 311                 } else {
 312                         (void)printf("I (s=%d,r=%d,%c)",
 313                                 LLC_I_NS(control),
 314                                 LLC_IS_NR(control),
 315                                 f);
 316                 }
 317                 p += 4;
 318                 length -= 4;
 319                 caplen -= 4;
 320         }
 321         return(1);
 322 }
 323
 324 int
 325 snap_print(const u_char *p, u_int length, u_int caplen,
 326     u_short *extracted_ethertype, u_int32_t orgcode, u_short et,
 327     u_int bridge_pad)
 328 {
 329         register int ret;
 330
 331         switch (orgcode) {
 332         case OUI_ENCAP_ETHER:
 333         case OUI_CISCO_90:
 334                 /*
 335                  * This is an encapsulated Ethernet packet,
 336                  * or a packet bridged by some piece of
 337                  * Cisco hardware; the protocol ID is
 338                  * an Ethernet protocol type.
 339                  */
 340                 ret = ether_encap_print(et, p, length, caplen,
 341                     extracted_ethertype);
 342                 if (ret)
 343                         return (ret);
 344                 break;
 345
 346         case OUI_APPLETALK:
 347                 if (et == ETHERTYPE_ATALK) {
 348                         /*
 349                          * No, I have no idea why Apple used one
 350                          * of their own OUIs, rather than
 351                          * 0x000000, and an Ethernet packet
 352                          * type, for Appletalk data packets,
 353                          * but used 0x000000 and an Ethernet
 354                          * packet type for AARP packets.
 355                          */
 356                         ret = ether_encap_print(et, p, length, caplen,
 357                             extracted_ethertype);
 358                         if (ret)
 359                                 return (ret);
 360                 }
 361                 break;
 362
 363         case OUI_CISCO:
 364                 if (et == PID_CISCO_CDP) {
 365                         cdp_print(p, length, caplen);
 366                         return (1);
 367                 }
 368                 break;
 369
 370         case OUI_RFC2684:
 371                 switch (et) {
 372
 373                 case PID_RFC2684_ETH_FCS:
 374                 case PID_RFC2684_ETH_NOFCS:
 375                         /*
 376                          * XXX - remove the last two bytes for
 377                          * PID_RFC2684_ETH_FCS?
 378                          */
 379                         /*
 380                          * Skip the padding.
 381                          */
 382                         caplen -= bridge_pad;
 383                         length -= bridge_pad;
 384                         p += bridge_pad;
 385
 386                         /*
 387                          * What remains is an Ethernet packet.
 388                          */
 389                         ether_print(p, length, caplen);
 390                         return (1);
 391
 392                 case PID_RFC2684_802_5_FCS:
 393                 case PID_RFC2684_802_5_NOFCS:
 394                         /*
 395                          * XXX - remove the last two bytes for
 396                          * PID_RFC2684_ETH_FCS?
 397                          */
 398                         /*
 399                          * Skip the padding, but not the Access
 400                          * Control field.
 401                          */
 402                         caplen -= bridge_pad;
 403                         length -= bridge_pad;
 404                         p += bridge_pad;
 405
 406                         /*
 407                          * What remains is an 802.5 Token Ring
 408                          * packet.
 409                          */
 410                         token_print(p, length, caplen);
 411                         return (1);
 412
 413                 case PID_RFC2684_FDDI_FCS:
 414                 case PID_RFC2684_FDDI_NOFCS:
 415                         /*
 416                          * XXX - remove the last two bytes for
 417                          * PID_RFC2684_ETH_FCS?
 418                          */
 419                         /*
 420                          * Skip the padding.
 421                          */
 422                         caplen -= bridge_pad + 1;
 423                         length -= bridge_pad + 1;
 424                         p += bridge_pad + 1;
 425
 426                         /*
 427                          * What remains is an FDDI packet.
 428                          */
 429                         fddi_print(p, length, caplen);
 430                         return (1);
 431
 432                 case PID_RFC2684_BPDU:
 433                         stp_print(p, length);
 434                         return (1);
 435                 }
 436         }
 437         return (0);
 438 }