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 1.47 2002-07-11 08:27:03 guy Exp $";
  28 #endif
  29
  30 #ifdef HAVE_CONFIG_H
  31 #include "config.h"
  32 #endif
  33
  34 #include <sys/param.h>
  35 #include <sys/time.h>
  36
  37 #include <netinet/in.h>
  38
  39 #include <ctype.h>
  40 #include <netdb.h>
  41 #include <stdio.h>
  42 #include <string.h>
  43
  44 #include "interface.h"
  45 #include "addrtoname.h"
  46 #include "extract.h"                    /* must come after interface.h */
  47
  48 #include "llc.h"
  49 #include "ethertype.h"
  50
  51 static struct tok cmd2str[] = {
  52         { LLC_UI,       "ui" },
  53         { LLC_TEST,     "test" },
  54         { LLC_XID,      "xid" },
  55         { LLC_UA,       "ua" },
  56         { LLC_DISC,     "disc" },
  57         { LLC_DM,       "dm" },
  58         { LLC_SABME,    "sabme" },
  59         { LLC_FRMR,     "frmr" },
  60         { 0,            NULL }
  61 };
  62
  63 /*
  64  * Returns non-zero IFF it succeeds in printing the header
  65  */
  66 int
  67 llc_print(const u_char *p, u_int length, u_int caplen,
  68           const u_char *esrc, const u_char *edst, u_short *extracted_ethertype)
  69 {
  70         struct llc llc;
  71         register u_short et;
  72         u_int16_t control;
  73         register int ret;
  74
  75         if (caplen < 3) {
  76                 (void)printf("[|llc]");
  77                 default_print((u_char *)p, caplen);
  78                 return(0);
  79         }
  80
  81         /* Watch out for possible alignment problems */
  82         memcpy((char *)&llc, (char *)p, min(caplen, sizeof(llc)));
  83
  84         if (llc.ssap == LLCSAP_GLOBAL && llc.dsap == LLCSAP_GLOBAL) {
  85                 /*
  86                  * This is an Ethernet_802.3 IPX frame; it has an
  87                  * 802.3 header (i.e., an Ethernet header where the
  88                  * type/length field is <= ETHERMTU, i.e. it's a length
  89                  * field, not a type field), but has no 802.2 header -
  90                  * the IPX packet starts right after the Ethernet header,
  91                  * with a signature of two bytes of 0xFF (which is
  92                  * LLCSAP_GLOBAL).
  93                  *
  94                  * (It might also have been an Ethernet_802.3 IPX at
  95                  * one time, but got bridged onto another network,
  96                  * such as an 802.11 network; this has appeared in at
  97                  * least one capture file.)
  98                  */
  99                 printf("(NOV-802.3) ");
 100                 ipx_print(p, length);
 101                 return (1);
 102         }
 103
 104         if (llc.ssap == LLCSAP_8021D && llc.dsap == LLCSAP_8021D) {
 105                 stp_print(p, length);
 106                 return (1);
 107         }
 108
 109         if (llc.ssap == LLCSAP_IPX && llc.dsap == LLCSAP_IPX &&
 110             llc.llcui == LLC_UI) {
 111                 /*
 112                  * This is an Ethernet_802.2 IPX frame, with an 802.3
 113                  * header and an 802.2 LLC header with the source and
 114                  * destination SAPs being the IPX SAP.
 115                  *
 116                  * Skip DSAP, LSAP, and control field.
 117                  */
 118                 printf("(NOV-802.2) ");
 119                 p += 3;
 120                 length -= 3;
 121                 caplen -= 3;
 122                 ipx_print(p, length);
 123                 return (1);
 124         }
 125
 126 #ifdef TCPDUMP_DO_SMB
 127         if (llc.ssap == LLCSAP_NETBEUI && llc.dsap == LLCSAP_NETBEUI
 128             && (!(llc.llcu & LLC_S_FMT) || llc.llcu == LLC_U_FMT)) {
 129                 /*
 130                  * we don't actually have a full netbeui parser yet, but the
 131                  * smb parser can handle many smb-in-netbeui packets, which
 132                  * is very useful, so we call that
 133                  *
 134                  * We don't call it for S frames, however, just I frames
 135                  * (which are frames that don't have the low-order bit,
 136                  * LLC_S_FMT, set in the first byte of the control field)
 137                  * and UI frames (whose control field is just 3, LLC_U_FMT).
 138                  */
 139
 140                 /*
 141                  * Skip the DSAP and LSAP.
 142                  */
 143                 p += 2;
 144                 length -= 2;
 145                 caplen -= 2;
 146
 147                 /*
 148                  * OK, what type of LLC frame is this?  The length
 149                  * of the control field depends on that - I frames
 150                  * have a two-byte control field, and U frames have
 151                  * a one-byte control field.
 152                  */
 153                 if (llc.llcu == LLC_U_FMT) {
 154                         control = llc.llcu;
 155                         p += 1;
 156                         length -= 1;
 157                         caplen -= 1;
 158                 } else {
 159                         /*
 160                          * The control field in I and S frames is
 161                          * little-endian.
 162                          */
 163                         control = EXTRACT_LE_16BITS(&llc.llcu);
 164                         p += 2;
 165                         length -= 2;
 166                         caplen -= 2;
 167                 }
 168                 netbeui_print(control, p, length);
 169                 return (1);
 170         }
 171 #endif
 172         if (llc.ssap == LLCSAP_ISONS && llc.dsap == LLCSAP_ISONS
 173             && llc.llcui == LLC_UI) {
 174                 isoclns_print(p + 3, length - 3, caplen - 3, esrc, edst);
 175                 return (1);
 176         }
 177
 178         if (llc.ssap == LLCSAP_SNAP && llc.dsap == LLCSAP_SNAP
 179             && llc.llcui == LLC_UI) {
 180                 u_int32_t orgcode;
 181
 182                 if (caplen < sizeof(llc)) {
 183                         (void)printf("[|llc-snap]");
 184                         default_print((u_char *)p, caplen);
 185                         return (0);
 186                 }
 187                 if (vflag)
 188                         (void)printf("snap %s ", protoid_string(llc.llcpi));
 189
 190                 caplen -= sizeof(llc);
 191                 length -= sizeof(llc);
 192                 p += sizeof(llc);
 193
 194                 orgcode = EXTRACT_24BITS(&llc.llc_orgcode[0]);
 195                 et = EXTRACT_16BITS(&llc.llc_ethertype[0]);
 196                 /*
 197                  * XXX - what *is* the right bridge pad value here?
 198                  * Does anybody ever bridge one form of LAN traffic
 199                  * over a networking type that uses 802.2 LLC?
 200                  */
 201                 ret = snap_print(p, length, caplen, esrc, edst,
 202                     extracted_ethertype, orgcode, et, 2);
 203                 if (ret)
 204                         return (ret);
 205         }
 206
 207         if ((llc.ssap & ~LLC_GSAP) == llc.dsap) {
 208                 if (eflag || esrc == NULL || edst == NULL)
 209                         (void)printf("%s ", llcsap_string(llc.dsap));
 210                 else
 211                         (void)printf("%s > %s %s ",
 212                                         etheraddr_string(esrc),
 213                                         etheraddr_string(edst),
 214                                         llcsap_string(llc.dsap));
 215         } else {
 216                 if (eflag || esrc == NULL || edst == NULL)
 217                         (void)printf("%s > %s ",
 218                                 llcsap_string(llc.ssap & ~LLC_GSAP),
 219                                 llcsap_string(llc.dsap));
 220                 else
 221                         (void)printf("%s %s > %s %s ",
 222                                 etheraddr_string(esrc),
 223                                 llcsap_string(llc.ssap & ~LLC_GSAP),
 224                                 etheraddr_string(edst),
 225                                 llcsap_string(llc.dsap));
 226         }
 227
 228         if ((llc.llcu & LLC_U_FMT) == LLC_U_FMT) {
 229                 u_int16_t cmd;
 230                 const char *m;
 231                 char f;
 232
 233                 cmd = LLC_U_CMD(llc.llcu);
 234                 m = tok2str(cmd2str, "%02x", cmd);
 235                 switch ((llc.ssap & LLC_GSAP) | (llc.llcu & LLC_U_POLL)) {
 236                         case 0:                 f = 'C'; break;
 237                         case LLC_GSAP:          f = 'R'; break;
 238                         case LLC_U_POLL:        f = 'P'; break;
 239                         case LLC_GSAP|LLC_U_POLL: f = 'F'; break;
 240                         default:                f = '?'; break;
 241                 }
 242
 243                 printf("%s/%c", m, f);
 244
 245                 p += 3;
 246                 length -= 3;
 247                 caplen -= 3;
 248
 249                 if ((llc.llcu & ~LLC_U_POLL) == LLC_XID) {
 250                         if (*p == LLC_XID_FI) {
 251                                 printf(": %02x %02x", p[1], p[2]);
 252                                 p += 3;
 253                                 length -= 3;
 254                                 caplen -= 3;
 255                         }
 256                 }
 257         } else {
 258                 char f;
 259
 260                 /*
 261                  * The control field in I and S frames is little-endian.
 262                  */
 263                 control = EXTRACT_LE_16BITS(&llc.llcu);
 264                 switch ((llc.ssap & LLC_GSAP) | (control & LLC_IS_POLL)) {
 265                         case 0:                 f = 'C'; break;
 266                         case LLC_GSAP:          f = 'R'; break;
 267                         case LLC_IS_POLL:       f = 'P'; break;
 268                         case LLC_GSAP|LLC_IS_POLL: f = 'F'; break;
 269                         default:                f = '?'; break;
 270                 }
 271
 272                 if ((control & LLC_S_FMT) == LLC_S_FMT) {
 273                         static char *llc_s[] = { "rr", "rej", "rnr", "03" };
 274                         (void)printf("%s (r=%d,%c)",
 275                                 llc_s[LLC_S_CMD(control)],
 276                                 LLC_IS_NR(control),
 277                                 f);
 278                 } else {
 279                         (void)printf("I (s=%d,r=%d,%c)",
 280                                 LLC_I_NS(control),
 281                                 LLC_IS_NR(control),
 282                                 f);
 283                 }
 284                 p += 4;
 285                 length -= 4;
 286                 caplen -= 4;
 287         }
 288         (void)printf(" len=%d", length);
 289         return(1);
 290 }
 291
 292 int
 293 snap_print(const u_char *p, u_int length, u_int caplen,
 294     const u_char *esrc, const u_char *edst, u_short *extracted_ethertype,
 295     u_int32_t orgcode, u_short et, u_int bridge_pad)
 296 {
 297         register int ret;
 298
 299         switch (orgcode) {
 300         case OUI_ENCAP_ETHER:
 301         case OUI_CISCO_90:
 302                 /*
 303                  * This is an encapsulated Ethernet packet,
 304                  * or a packet bridged by some piece of
 305                  * Cisco hardware; the protocol ID is
 306                  * an Ethernet protocol type.
 307                  */
 308                 ret = ether_encap_print(et, p, length, caplen,
 309                     extracted_ethertype);
 310                 if (ret)
 311                         return (ret);
 312                 break;
 313
 314         case OUI_APPLETALK:
 315                 if (et == ETHERTYPE_ATALK) {
 316                         /*
 317                          * No, I have no idea why Apple used one
 318                          * of their own OUIs, rather than
 319                          * 0x000000, and an Ethernet packet
 320                          * type, for Appletalk data packets,
 321                          * but used 0x000000 and an Ethernet
 322                          * packet type for AARP packets.
 323                          */
 324                         ret = ether_encap_print(et, p, length, caplen,
 325                             extracted_ethertype);
 326                         if (ret)
 327                                 return (ret);
 328                 }
 329                 break;
 330
 331         case OUI_CISCO:
 332                 if (et == PID_CISCO_CDP) {
 333                         cdp_print(p, length, caplen, esrc, edst);
 334                         return (1);
 335                 }
 336                 break;
 337
 338         case OUI_RFC2684:
 339                 switch (et) {
 340
 341                 case PID_RFC2684_ETH_FCS:
 342                 case PID_RFC2684_ETH_NOFCS:
 343                         /*
 344                          * XXX - remove the last two bytes for
 345                          * PID_RFC2684_ETH_FCS?
 346                          */
 347                         /*
 348                          * Skip the padding.
 349                          */
 350                         caplen -= bridge_pad;
 351                         length -= bridge_pad;
 352                         p += bridge_pad;
 353
 354                         /*
 355                          * What remains is an Ethernet packet.
 356                          */
 357                         ether_print(p, length, caplen);
 358                         return (1);
 359
 360                 case PID_RFC2684_802_5_FCS:
 361                 case PID_RFC2684_802_5_NOFCS:
 362                         /*
 363                          * XXX - remove the last two bytes for
 364                          * PID_RFC2684_ETH_FCS?
 365                          */
 366                         /*
 367                          * Skip the padding, but not the Access
 368                          * Control field.
 369                          */
 370                         caplen -= bridge_pad;
 371                         length -= bridge_pad;
 372                         p += bridge_pad;
 373
 374                         /*
 375                          * What remains is an 802.5 Token Ring
 376                          * packet.
 377                          */
 378                         token_print(p, length, caplen);
 379                         return (1);
 380
 381                 case PID_RFC2684_FDDI_FCS:
 382                 case PID_RFC2684_FDDI_NOFCS:
 383                         /*
 384                          * XXX - remove the last two bytes for
 385                          * PID_RFC2684_ETH_FCS?
 386                          */
 387                         /*
 388                          * Skip the padding.
 389                          */
 390                         caplen -= bridge_pad + 1;
 391                         length -= bridge_pad + 1;
 392                         p += bridge_pad + 1;
 393
 394                         /*
 395                          * What remains is an FDDI packet.
 396                          */
 397                         fddi_print(p, length, caplen);
 398                         return (1);
 399
 400                 case PID_RFC2684_BPDU:
 401                         stp_print(p, length);
 402                         return (1);
 403                 }
 404         }
 405         return (0);
 406 }