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[] =
  27     "@(#) $Header: /tcpdump/master/tcpdump/print-llc.c,v 1.50 2002-09-05 21:25:44 guy 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 cmd2str[] = {
  47         { LLC_UI,       "ui" },
  48         { LLC_TEST,     "test" },
  49         { LLC_XID,      "xid" },
  50         { LLC_UA,       "ua" },
  51         { LLC_DISC,     "disc" },
  52         { LLC_DM,       "dm" },
  53         { LLC_SABME,    "sabme" },
  54         { LLC_FRMR,     "frmr" },
  55         { 0,            NULL }
  56 };
  57
  58 /*
  59  * Returns non-zero IFF it succeeds in printing the header
  60  */
  61 int
  62 llc_print(const u_char *p, u_int length, u_int caplen,
  63           const u_char *esrc, const u_char *edst, u_short *extracted_ethertype)
  64 {
  65         struct llc llc;
  66         register u_short et;
  67         u_int16_t control;
  68         register int ret;
  69
  70         if (caplen < 3) {
  71                 (void)printf("[|llc]");
  72                 default_print((u_char *)p, caplen);
  73                 return(0);
  74         }
  75
  76         /* Watch out for possible alignment problems */
  77         memcpy((char *)&llc, (char *)p, min(caplen, sizeof(llc)));
  78
  79         if (llc.ssap == LLCSAP_GLOBAL && llc.dsap == LLCSAP_GLOBAL) {
  80                 /*
  81                  * This is an Ethernet_802.3 IPX frame; it has an
  82                  * 802.3 header (i.e., an Ethernet header where the
  83                  * type/length field is <= ETHERMTU, i.e. it's a length
  84                  * field, not a type field), but has no 802.2 header -
  85                  * the IPX packet starts right after the Ethernet header,
  86                  * with a signature of two bytes of 0xFF (which is
  87                  * LLCSAP_GLOBAL).
  88                  *
  89                  * (It might also have been an Ethernet_802.3 IPX at
  90                  * one time, but got bridged onto another network,
  91                  * such as an 802.11 network; this has appeared in at
  92                  * least one capture file.)
  93                  */
  94                 printf("(NOV-802.3) ");
  95                 ipx_print(p, length);
  96                 return (1);
  97         }
  98
  99         if (llc.ssap == LLCSAP_8021D && llc.dsap == LLCSAP_8021D) {
 100                 stp_print(p, length);
 101                 return (1);
 102         }
 103
 104         if (llc.ssap == LLCSAP_IPX && llc.dsap == LLCSAP_IPX &&
 105             llc.llcui == LLC_UI) {
 106                 /*
 107                  * This is an Ethernet_802.2 IPX frame, with an 802.3
 108                  * header and an 802.2 LLC header with the source and
 109                  * destination SAPs being the IPX SAP.
 110                  *
 111                  * Skip DSAP, LSAP, and control field.
 112                  */
 113                 printf("(NOV-802.2) ");
 114                 p += 3;
 115                 length -= 3;
 116                 caplen -= 3;
 117                 ipx_print(p, length);
 118                 return (1);
 119         }
 120
 121 #ifdef TCPDUMP_DO_SMB
 122         if (llc.ssap == LLCSAP_NETBEUI && llc.dsap == LLCSAP_NETBEUI
 123             && (!(llc.llcu & LLC_S_FMT) || llc.llcu == LLC_U_FMT)) {
 124                 /*
 125                  * we don't actually have a full netbeui parser yet, but the
 126                  * smb parser can handle many smb-in-netbeui packets, which
 127                  * is very useful, so we call that
 128                  *
 129                  * We don't call it for S frames, however, just I frames
 130                  * (which are frames that don't have the low-order bit,
 131                  * LLC_S_FMT, set in the first byte of the control field)
 132                  * and UI frames (whose control field is just 3, LLC_U_FMT).
 133                  */
 134
 135                 /*
 136                  * Skip the DSAP and LSAP.
 137                  */
 138                 p += 2;
 139                 length -= 2;
 140                 caplen -= 2;
 141
 142                 /*
 143                  * OK, what type of LLC frame is this?  The length
 144                  * of the control field depends on that - I frames
 145                  * have a two-byte control field, and U frames have
 146                  * a one-byte control field.
 147                  */
 148                 if (llc.llcu == LLC_U_FMT) {
 149                         control = llc.llcu;
 150                         p += 1;
 151                         length -= 1;
 152                         caplen -= 1;
 153                 } else {
 154                         /*
 155                          * The control field in I and S frames is
 156                          * little-endian.
 157                          */
 158                         control = EXTRACT_LE_16BITS(&llc.llcu);
 159                         p += 2;
 160                         length -= 2;
 161                         caplen -= 2;
 162                 }
 163                 netbeui_print(control, p, length);
 164                 return (1);
 165         }
 166 #endif
 167         if (llc.ssap == LLCSAP_ISONS && llc.dsap == LLCSAP_ISONS
 168             && llc.llcui == LLC_UI) {
 169                 isoclns_print(p + 3, length - 3, caplen - 3, esrc, edst);
 170                 return (1);
 171         }
 172
 173         if (llc.ssap == LLCSAP_SNAP && llc.dsap == LLCSAP_SNAP
 174             && llc.llcui == LLC_UI) {
 175                 u_int32_t orgcode;
 176
 177                 if (caplen < sizeof(llc)) {
 178                         (void)printf("[|llc-snap]");
 179                         default_print((u_char *)p, caplen);
 180                         return (0);
 181                 }
 182                 if (vflag)
 183                         (void)printf("snap %s ", protoid_string(llc.llcpi));
 184
 185                 caplen -= sizeof(llc);
 186                 length -= sizeof(llc);
 187                 p += sizeof(llc);
 188
 189                 orgcode = EXTRACT_24BITS(&llc.llc_orgcode[0]);
 190                 et = EXTRACT_16BITS(&llc.llc_ethertype[0]);
 191                 /*
 192                  * XXX - what *is* the right bridge pad value here?
 193                  * Does anybody ever bridge one form of LAN traffic
 194                  * over a networking type that uses 802.2 LLC?
 195                  */
 196                 ret = snap_print(p, length, caplen, extracted_ethertype,
 197                     orgcode, et, 2);
 198                 if (ret)
 199                         return (ret);
 200         }
 201
 202         if ((llc.ssap & ~LLC_GSAP) == llc.dsap) {
 203                 if (eflag || esrc == NULL || edst == NULL)
 204                         (void)printf("%s ", llcsap_string(llc.dsap));
 205                 else
 206                         (void)printf("%s > %s %s ",
 207                                         etheraddr_string(esrc),
 208                                         etheraddr_string(edst),
 209                                         llcsap_string(llc.dsap));
 210         } else {
 211                 if (eflag || esrc == NULL || edst == NULL)
 212                         (void)printf("%s > %s ",
 213                                 llcsap_string(llc.ssap & ~LLC_GSAP),
 214                                 llcsap_string(llc.dsap));
 215                 else
 216                         (void)printf("%s %s > %s %s ",
 217                                 etheraddr_string(esrc),
 218                                 llcsap_string(llc.ssap & ~LLC_GSAP),
 219                                 etheraddr_string(edst),
 220                                 llcsap_string(llc.dsap));
 221         }
 222
 223         if ((llc.llcu & LLC_U_FMT) == LLC_U_FMT) {
 224                 u_int16_t cmd;
 225                 const char *m;
 226                 char f;
 227
 228                 cmd = LLC_U_CMD(llc.llcu);
 229                 m = tok2str(cmd2str, "%02x", cmd);
 230                 switch ((llc.ssap & LLC_GSAP) | (llc.llcu & LLC_U_POLL)) {
 231                         case 0:                 f = 'C'; break;
 232                         case LLC_GSAP:          f = 'R'; break;
 233                         case LLC_U_POLL:        f = 'P'; break;
 234                         case LLC_GSAP|LLC_U_POLL: f = 'F'; break;
 235                         default:                f = '?'; break;
 236                 }
 237
 238                 printf("%s/%c", m, f);
 239
 240                 p += 3;
 241                 length -= 3;
 242                 caplen -= 3;
 243
 244                 if ((llc.llcu & ~LLC_U_POLL) == LLC_XID) {
 245                         if (*p == LLC_XID_FI) {
 246                                 printf(": %02x %02x", p[1], p[2]);
 247                                 p += 3;
 248                                 length -= 3;
 249                                 caplen -= 3;
 250                         }
 251                 }
 252         } else {
 253                 char f;
 254
 255                 /*
 256                  * The control field in I and S frames is little-endian.
 257                  */
 258                 control = EXTRACT_LE_16BITS(&llc.llcu);
 259                 switch ((llc.ssap & LLC_GSAP) | (control & LLC_IS_POLL)) {
 260                         case 0:                 f = 'C'; break;
 261                         case LLC_GSAP:          f = 'R'; break;
 262                         case LLC_IS_POLL:       f = 'P'; break;
 263                         case LLC_GSAP|LLC_IS_POLL: f = 'F'; break;
 264                         default:                f = '?'; break;
 265                 }
 266
 267                 if ((control & LLC_S_FMT) == LLC_S_FMT) {
 268                         static const char *llc_s[] = { "rr", "rej", "rnr", "03" };
 269                         (void)printf("%s (r=%d,%c)",
 270                                 llc_s[LLC_S_CMD(control)],
 271                                 LLC_IS_NR(control),
 272                                 f);
 273                 } else {
 274                         (void)printf("I (s=%d,r=%d,%c)",
 275                                 LLC_I_NS(control),
 276                                 LLC_IS_NR(control),
 277                                 f);
 278                 }
 279                 p += 4;
 280                 length -= 4;
 281                 caplen -= 4;
 282         }
 283         (void)printf(" len=%d", length);
 284         return(1);
 285 }
 286
 287 int
 288 snap_print(const u_char *p, u_int length, u_int caplen,
 289     u_short *extracted_ethertype, u_int32_t orgcode, u_short et,
 290     u_int bridge_pad)
 291 {
 292         register int ret;
 293
 294         switch (orgcode) {
 295         case OUI_ENCAP_ETHER:
 296         case OUI_CISCO_90:
 297                 /*
 298                  * This is an encapsulated Ethernet packet,
 299                  * or a packet bridged by some piece of
 300                  * Cisco hardware; the protocol ID is
 301                  * an Ethernet protocol type.
 302                  */
 303                 ret = ether_encap_print(et, p, length, caplen,
 304                     extracted_ethertype);
 305                 if (ret)
 306                         return (ret);
 307                 break;
 308
 309         case OUI_APPLETALK:
 310                 if (et == ETHERTYPE_ATALK) {
 311                         /*
 312                          * No, I have no idea why Apple used one
 313                          * of their own OUIs, rather than
 314                          * 0x000000, and an Ethernet packet
 315                          * type, for Appletalk data packets,
 316                          * but used 0x000000 and an Ethernet
 317                          * packet type for AARP packets.
 318                          */
 319                         ret = ether_encap_print(et, p, length, caplen,
 320                             extracted_ethertype);
 321                         if (ret)
 322                                 return (ret);
 323                 }
 324                 break;
 325
 326         case OUI_CISCO:
 327                 if (et == PID_CISCO_CDP) {
 328                         cdp_print(p, length, caplen);
 329                         return (1);
 330                 }
 331                 break;
 332
 333         case OUI_RFC2684:
 334                 switch (et) {
 335
 336                 case PID_RFC2684_ETH_FCS:
 337                 case PID_RFC2684_ETH_NOFCS:
 338                         /*
 339                          * XXX - remove the last two bytes for
 340                          * PID_RFC2684_ETH_FCS?
 341                          */
 342                         /*
 343                          * Skip the padding.
 344                          */
 345                         caplen -= bridge_pad;
 346                         length -= bridge_pad;
 347                         p += bridge_pad;
 348
 349                         /*
 350                          * What remains is an Ethernet packet.
 351                          */
 352                         ether_print(p, length, caplen);
 353                         return (1);
 354
 355                 case PID_RFC2684_802_5_FCS:
 356                 case PID_RFC2684_802_5_NOFCS:
 357                         /*
 358                          * XXX - remove the last two bytes for
 359                          * PID_RFC2684_ETH_FCS?
 360                          */
 361                         /*
 362                          * Skip the padding, but not the Access
 363                          * Control field.
 364                          */
 365                         caplen -= bridge_pad;
 366                         length -= bridge_pad;
 367                         p += bridge_pad;
 368
 369                         /*
 370                          * What remains is an 802.5 Token Ring
 371                          * packet.
 372                          */
 373                         token_print(p, length, caplen);
 374                         return (1);
 375
 376                 case PID_RFC2684_FDDI_FCS:
 377                 case PID_RFC2684_FDDI_NOFCS:
 378                         /*
 379                          * XXX - remove the last two bytes for
 380                          * PID_RFC2684_ETH_FCS?
 381                          */
 382                         /*
 383                          * Skip the padding.
 384                          */
 385                         caplen -= bridge_pad + 1;
 386                         length -= bridge_pad + 1;
 387                         p += bridge_pad + 1;
 388
 389                         /*
 390                          * What remains is an FDDI packet.
 391                          */
 392                         fddi_print(p, length, caplen);
 393                         return (1);
 394
 395                 case PID_RFC2684_BPDU:
 396                         stp_print(p, length);
 397                         return (1);
 398                 }
 399         }
 400         return (0);
 401 }