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 1.53.2.2 2003-11-16 08:51:32 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 (eflag)
  80           printf("LLC, dsap 0x%02x, ssap 0x%02x, cmd 0x%02x, ",
  81                  llc.dsap,
  82                  llc.ssap,
  83                  llc.llcu);
  84
  85         if (llc.ssap == LLCSAP_GLOBAL && llc.dsap == LLCSAP_GLOBAL) {
  86                 /*
  87                  * This is an Ethernet_802.3 IPX frame; it has an
  88                  * 802.3 header (i.e., an Ethernet header where the
  89                  * type/length field is <= ETHERMTU, i.e. it's a length
  90                  * field, not a type field), but has no 802.2 header -
  91                  * the IPX packet starts right after the Ethernet header,
  92                  * with a signature of two bytes of 0xFF (which is
  93                  * LLCSAP_GLOBAL).
  94                  *
  95                  * (It might also have been an Ethernet_802.3 IPX at
  96                  * one time, but got bridged onto another network,
  97                  * such as an 802.11 network; this has appeared in at
  98                  * least one capture file.)
  99                  */
 100                 printf("(NOV-802.3) ");
 101                 ipx_print(p, length);
 102                 return (1);
 103         }
 104
 105         if (llc.ssap == LLCSAP_8021D && llc.dsap == LLCSAP_8021D) {
 106                 stp_print(p, length);
 107                 return (1);
 108         }
 109
 110         if (llc.ssap == LLCSAP_IP && llc.dsap == LLCSAP_IP) {
 111                 ip_print(p+4, length-4);
 112                 return (1);
 113         }
 114
 115         if (llc.ssap == LLCSAP_IPX && llc.dsap == LLCSAP_IPX &&
 116             llc.llcui == LLC_UI) {
 117                 /*
 118                  * This is an Ethernet_802.2 IPX frame, with an 802.3
 119                  * header and an 802.2 LLC header with the source and
 120                  * destination SAPs being the IPX SAP.
 121                  *
 122                  * Skip DSAP, LSAP, and control field.
 123                  */
 124                 printf("(NOV-802.2) ");
 125                 p += 3;
 126                 length -= 3;
 127                 caplen -= 3;
 128                 ipx_print(p, length);
 129                 return (1);
 130         }
 131
 132 #ifdef TCPDUMP_DO_SMB
 133         if (llc.ssap == LLCSAP_NETBEUI && llc.dsap == LLCSAP_NETBEUI
 134             && (!(llc.llcu & LLC_S_FMT) || llc.llcu == LLC_U_FMT)) {
 135                 /*
 136                  * we don't actually have a full netbeui parser yet, but the
 137                  * smb parser can handle many smb-in-netbeui packets, which
 138                  * is very useful, so we call that
 139                  *
 140                  * We don't call it for S frames, however, just I frames
 141                  * (which are frames that don't have the low-order bit,
 142                  * LLC_S_FMT, set in the first byte of the control field)
 143                  * and UI frames (whose control field is just 3, LLC_U_FMT).
 144                  */
 145
 146                 /*
 147                  * Skip the DSAP and LSAP.
 148                  */
 149                 p += 2;
 150                 length -= 2;
 151                 caplen -= 2;
 152
 153                 /*
 154                  * OK, what type of LLC frame is this?  The length
 155                  * of the control field depends on that - I frames
 156                  * have a two-byte control field, and U frames have
 157                  * a one-byte control field.
 158                  */
 159                 if (llc.llcu == LLC_U_FMT) {
 160                         control = llc.llcu;
 161                         p += 1;
 162                         length -= 1;
 163                         caplen -= 1;
 164                 } else {
 165                         /*
 166                          * The control field in I and S frames is
 167                          * little-endian.
 168                          */
 169                         control = EXTRACT_LE_16BITS(&llc.llcu);
 170                         p += 2;
 171                         length -= 2;
 172                         caplen -= 2;
 173                 }
 174                 netbeui_print(control, p, length);
 175                 return (1);
 176         }
 177 #endif
 178         if (llc.ssap == LLCSAP_ISONS && llc.dsap == LLCSAP_ISONS
 179             && llc.llcui == LLC_UI) {
 180                 isoclns_print(p + 3, length - 3, caplen - 3);
 181                 return (1);
 182         }
 183
 184         if (llc.ssap == LLCSAP_SNAP && llc.dsap == LLCSAP_SNAP
 185             && llc.llcui == LLC_UI) {
 186                 u_int32_t orgcode;
 187
 188                 if (caplen < sizeof(llc)) {
 189                         (void)printf("[|llc-snap]");
 190                         default_print((u_char *)p, caplen);
 191                         return (0);
 192                 }
 193                 if (vflag)
 194                         (void)printf("snap %s ", protoid_string(llc.llcpi));
 195
 196                 caplen -= sizeof(llc);
 197                 length -= sizeof(llc);
 198                 p += sizeof(llc);
 199
 200                 orgcode = EXTRACT_24BITS(&llc.llc_orgcode[0]);
 201                 et = EXTRACT_16BITS(&llc.llc_ethertype[0]);
 202                 /*
 203                  * XXX - what *is* the right bridge pad value here?
 204                  * Does anybody ever bridge one form of LAN traffic
 205                  * over a networking type that uses 802.2 LLC?
 206                  */
 207                 ret = snap_print(p, length, caplen, extracted_ethertype,
 208                     orgcode, et, 2);
 209                 if (ret)
 210                         return (ret);
 211         }
 212
 213         if ((llc.ssap & ~LLC_GSAP) == llc.dsap) {
 214                 if (eflag || esrc == NULL || edst == NULL)
 215                         (void)printf("%s ", llcsap_string(llc.dsap));
 216                 else
 217                         (void)printf("%s > %s %s ",
 218                                         etheraddr_string(esrc),
 219                                         etheraddr_string(edst),
 220                                         llcsap_string(llc.dsap));
 221         } else {
 222                 if (eflag || esrc == NULL || edst == NULL)
 223                         (void)printf("%s > %s ",
 224                                 llcsap_string(llc.ssap & ~LLC_GSAP),
 225                                 llcsap_string(llc.dsap));
 226                 else
 227                         (void)printf("%s %s > %s %s ",
 228                                 etheraddr_string(esrc),
 229                                 llcsap_string(llc.ssap & ~LLC_GSAP),
 230                                 etheraddr_string(edst),
 231                                 llcsap_string(llc.dsap));
 232         }
 233
 234         if ((llc.llcu & LLC_U_FMT) == LLC_U_FMT) {
 235                 u_int16_t cmd;
 236                 const char *m;
 237                 char f;
 238
 239                 cmd = LLC_U_CMD(llc.llcu);
 240                 m = tok2str(cmd2str, "%02x", cmd);
 241                 switch ((llc.ssap & LLC_GSAP) | (llc.llcu & LLC_U_POLL)) {
 242                         case 0:                 f = 'C'; break;
 243                         case LLC_GSAP:          f = 'R'; break;
 244                         case LLC_U_POLL:        f = 'P'; break;
 245                         case LLC_GSAP|LLC_U_POLL: f = 'F'; break;
 246                         default:                f = '?'; break;
 247                 }
 248
 249                 printf("%s/%c", m, f);
 250
 251                 p += 3;
 252                 length -= 3;
 253                 caplen -= 3;
 254
 255                 if ((llc.llcu & ~LLC_U_POLL) == LLC_XID) {
 256                         if (*p == LLC_XID_FI) {
 257                                 printf(": %02x %02x", p[1], p[2]);
 258                                 p += 3;
 259                                 length -= 3;
 260                                 caplen -= 3;
 261                         }
 262                 }
 263         } else {
 264                 char f;
 265
 266                 /*
 267                  * The control field in I and S frames is little-endian.
 268                  */
 269                 control = EXTRACT_LE_16BITS(&llc.llcu);
 270                 switch ((llc.ssap & LLC_GSAP) | (control & LLC_IS_POLL)) {
 271                         case 0:                 f = 'C'; break;
 272                         case LLC_GSAP:          f = 'R'; break;
 273                         case LLC_IS_POLL:       f = 'P'; break;
 274                         case LLC_GSAP|LLC_IS_POLL: f = 'F'; break;
 275                         default:                f = '?'; break;
 276                 }
 277
 278                 if ((control & LLC_S_FMT) == LLC_S_FMT) {
 279                         static const char *llc_s[] = { "rr", "rej", "rnr", "03" };
 280                         (void)printf("%s (r=%d,%c)",
 281                                 llc_s[LLC_S_CMD(control)],
 282                                 LLC_IS_NR(control),
 283                                 f);
 284                 } else {
 285                         (void)printf("I (s=%d,r=%d,%c)",
 286                                 LLC_I_NS(control),
 287                                 LLC_IS_NR(control),
 288                                 f);
 289                 }
 290                 p += 4;
 291                 length -= 4;
 292                 caplen -= 4;
 293         }
 294         (void)printf(" len=%d", length);
 295         return(1);
 296 }
 297
 298 int
 299 snap_print(const u_char *p, u_int length, u_int caplen,
 300     u_short *extracted_ethertype, u_int32_t orgcode, u_short et,
 301     u_int bridge_pad)
 302 {
 303         register int ret;
 304
 305         switch (orgcode) {
 306         case OUI_ENCAP_ETHER:
 307         case OUI_CISCO_90:
 308                 /*
 309                  * This is an encapsulated Ethernet packet,
 310                  * or a packet bridged by some piece of
 311                  * Cisco hardware; the protocol ID is
 312                  * an Ethernet protocol type.
 313                  */
 314                 ret = ether_encap_print(et, p, length, caplen,
 315                     extracted_ethertype);
 316                 if (ret)
 317                         return (ret);
 318                 break;
 319
 320         case OUI_APPLETALK:
 321                 if (et == ETHERTYPE_ATALK) {
 322                         /*
 323                          * No, I have no idea why Apple used one
 324                          * of their own OUIs, rather than
 325                          * 0x000000, and an Ethernet packet
 326                          * type, for Appletalk data packets,
 327                          * but used 0x000000 and an Ethernet
 328                          * packet type for AARP packets.
 329                          */
 330                         ret = ether_encap_print(et, p, length, caplen,
 331                             extracted_ethertype);
 332                         if (ret)
 333                                 return (ret);
 334                 }
 335                 break;
 336
 337         case OUI_CISCO:
 338                 if (et == PID_CISCO_CDP) {
 339                         cdp_print(p, length, caplen);
 340                         return (1);
 341                 }
 342                 break;
 343
 344         case OUI_RFC2684:
 345                 switch (et) {
 346
 347                 case PID_RFC2684_ETH_FCS:
 348                 case PID_RFC2684_ETH_NOFCS:
 349                         /*
 350                          * XXX - remove the last two bytes for
 351                          * PID_RFC2684_ETH_FCS?
 352                          */
 353                         /*
 354                          * Skip the padding.
 355                          */
 356                         caplen -= bridge_pad;
 357                         length -= bridge_pad;
 358                         p += bridge_pad;
 359
 360                         /*
 361                          * What remains is an Ethernet packet.
 362                          */
 363                         ether_print(p, length, caplen);
 364                         return (1);
 365
 366                 case PID_RFC2684_802_5_FCS:
 367                 case PID_RFC2684_802_5_NOFCS:
 368                         /*
 369                          * XXX - remove the last two bytes for
 370                          * PID_RFC2684_ETH_FCS?
 371                          */
 372                         /*
 373                          * Skip the padding, but not the Access
 374                          * Control field.
 375                          */
 376                         caplen -= bridge_pad;
 377                         length -= bridge_pad;
 378                         p += bridge_pad;
 379
 380                         /*
 381                          * What remains is an 802.5 Token Ring
 382                          * packet.
 383                          */
 384                         token_print(p, length, caplen);
 385                         return (1);
 386
 387                 case PID_RFC2684_FDDI_FCS:
 388                 case PID_RFC2684_FDDI_NOFCS:
 389                         /*
 390                          * XXX - remove the last two bytes for
 391                          * PID_RFC2684_ETH_FCS?
 392                          */
 393                         /*
 394                          * Skip the padding.
 395                          */
 396                         caplen -= bridge_pad + 1;
 397                         length -= bridge_pad + 1;
 398                         p += bridge_pad + 1;
 399
 400                         /*
 401                          * What remains is an FDDI packet.
 402                          */
 403                         fddi_print(p, length, caplen);
 404                         return (1);
 405
 406                 case PID_RFC2684_BPDU:
 407                         stp_print(p, length);
 408                         return (1);
 409                 }
 410         }
 411         return (0);
 412 }