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 1.40 2001-07-21 23:14:23 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                 ipx_print(p, length);
 100                 return (1);
 101         }
 102
 103         if (llc.ssap == LLCSAP_8021D && llc.dsap == LLCSAP_8021D) {
 104                 stp_print(p, length);
 105                 return (1);
 106         }
 107
 108         if (llc.ssap == LLCSAP_IPX && llc.dsap == LLCSAP_IPX &&
 109             llc.llcui == LLC_UI) {
 110                 /*
 111                  * This is an Ethernet_802.2 IPX frame, with an 802.3
 112                  * header and an 802.2 LLC header with the source and
 113                  * destination SAPs being the IPX SAP.
 114                  *
 115                  * Skip DSAP, LSAP, and control field.
 116                  */
 117                 p += 3;
 118                 length -= 3;
 119                 caplen -= 3;
 120                 ipx_print(p, length);
 121                 return (1);
 122         }
 123
 124         if (llc.ssap == LLCSAP_NETBEUI && llc.dsap == LLCSAP_NETBEUI
 125             && (!(llc.llcu & LLC_S_FMT) || llc.llcu == LLC_U_FMT)) {
 126                 /*
 127                  * we don't actually have a full netbeui parser yet, but the
 128                  * smb parser can handle many smb-in-netbeui packets, which
 129                  * is very useful, so we call that
 130                  *
 131                  * We don't call it for S frames, however, just I frames
 132                  * (which are frames that don't have the low-order bit,
 133                  * LLC_S_FMT, set in the first byte of the control field)
 134                  * and UI frames (whose control field is just 3, LLC_U_FMT).
 135                  */
 136
 137                 /*
 138                  * Skip the DSAP and LSAP.
 139                  */
 140                 p += 2;
 141                 length -= 2;
 142                 caplen -= 2;
 143
 144                 /*
 145                  * OK, what type of LLC frame is this?  The length
 146                  * of the control field depends on that - I frames
 147                  * have a two-byte control field, and U frames have
 148                  * a one-byte control field.
 149                  */
 150                 if (llc.llcu == LLC_U_FMT) {
 151                         control = llc.llcu;
 152                         p += 1;
 153                         length -= 1;
 154                         caplen -= 1;
 155                 } else {
 156                         /*
 157                          * The control field in I and S frames is
 158                          * little-endian.
 159                          */
 160                         control = EXTRACT_LE_16BITS(&llc.llcu);
 161                         p += 2;
 162                         length -= 2;
 163                         caplen -= 2;
 164                 }
 165                 netbeui_print(control, p, length);
 166                 return (1);
 167         }
 168         if (llc.ssap == LLCSAP_ISONS && llc.dsap == LLCSAP_ISONS
 169             && llc.llcui == LLC_UI) {
 170                 isoclns_print(p + 3, length - 3, caplen - 3, esrc, edst);
 171                 return (1);
 172         }
 173
 174         if (llc.ssap == LLCSAP_SNAP && llc.dsap == LLCSAP_SNAP
 175             && llc.llcui == LLC_UI) {
 176                 u_int32_t orgcode;
 177
 178                 if (caplen < sizeof(llc)) {
 179                         (void)printf("[|llc-snap]");
 180                         default_print((u_char *)p, caplen);
 181                         return (0);
 182                 }
 183                 if (vflag)
 184                         (void)printf("snap %s ", protoid_string(llc.llcpi));
 185
 186                 caplen -= sizeof(llc);
 187                 length -= sizeof(llc);
 188                 p += sizeof(llc);
 189
 190                 orgcode = EXTRACT_24BITS(&llc.llc_orgcode[0]);
 191                 et = EXTRACT_16BITS(&llc.llc_ethertype[0]);
 192                 switch (orgcode) {
 193                 case OUI_ENCAP_ETHER:
 194                 case OUI_CISCO_90:
 195                         /*
 196                          * This is an encapsulated Ethernet packet,
 197                          * or a packet bridged by some piece of
 198                          * Cisco hardware; the protocol ID is
 199                          * an Ethernet protocol type.
 200                          */
 201                         ret = ether_encap_print(et, p, length, caplen,
 202                             extracted_ethertype);
 203                         if (ret)
 204                                 return (ret);
 205                         break;
 206
 207                 case OUI_APPLETALK:
 208                         if (et == ETHERTYPE_ATALK) {
 209                                 /*
 210                                  * No, I have no idea why Apple used one
 211                                  * of their own OUIs, rather than
 212                                  * 0x000000, and an Ethernet packet
 213                                  * type, for Appletalk data packets,
 214                                  * but used 0x000000 and an Ethernet
 215                                  * packet type for AARP packets.
 216                                  */
 217                                 ret = ether_encap_print(et, p, length, caplen,
 218                                     extracted_ethertype);
 219                                 if (ret)
 220                                         return (ret);
 221                         }
 222                         break;
 223
 224                 case OUI_CISCO:
 225                         if (et == ETHERTYPE_CISCO_CDP) {
 226                                 cdp_print(p, length, caplen, esrc, edst);
 227                                 return 1;
 228                         }
 229                         break;
 230                 }
 231         }
 232
 233         if ((llc.ssap & ~LLC_GSAP) == llc.dsap) {
 234                 if (eflag)
 235                         (void)printf("%s ", llcsap_string(llc.dsap));
 236                 else
 237                         (void)printf("%s > %s %s ",
 238                                         etheraddr_string(esrc),
 239                                         etheraddr_string(edst),
 240                                         llcsap_string(llc.dsap));
 241         } else {
 242                 if (eflag)
 243                         (void)printf("%s > %s ",
 244                                 llcsap_string(llc.ssap & ~LLC_GSAP),
 245                                 llcsap_string(llc.dsap));
 246                 else
 247                         (void)printf("%s %s > %s %s ",
 248                                 etheraddr_string(esrc),
 249                                 llcsap_string(llc.ssap & ~LLC_GSAP),
 250                                 etheraddr_string(edst),
 251                                 llcsap_string(llc.dsap));
 252         }
 253
 254         if ((llc.llcu & LLC_U_FMT) == LLC_U_FMT) {
 255                 u_int16_t cmd;
 256                 const char *m;
 257                 char f;
 258
 259                 cmd = LLC_U_CMD(llc.llcu);
 260                 m = tok2str(cmd2str, "%02x", cmd);
 261                 switch ((llc.ssap & LLC_GSAP) | (llc.llcu & LLC_U_POLL)) {
 262                         case 0:                 f = 'C'; break;
 263                         case LLC_GSAP:          f = 'R'; break;
 264                         case LLC_U_POLL:        f = 'P'; break;
 265                         case LLC_GSAP|LLC_U_POLL: f = 'F'; break;
 266                         default:                f = '?'; break;
 267                 }
 268
 269                 printf("%s/%c", m, f);
 270
 271                 p += 3;
 272                 length -= 3;
 273                 caplen -= 3;
 274
 275                 if ((llc.llcu & ~LLC_U_POLL) == LLC_XID) {
 276                         if (*p == LLC_XID_FI) {
 277                                 printf(": %02x %02x", p[1], p[2]);
 278                                 p += 3;
 279                                 length -= 3;
 280                                 caplen -= 3;
 281                         }
 282                 }
 283         } else {
 284                 char f;
 285
 286                 /*
 287                  * The control field in I and S frames is little-endian.
 288                  */
 289                 control = EXTRACT_LE_16BITS(&llc.llcu);
 290                 switch ((llc.ssap & LLC_GSAP) | (control & LLC_IS_POLL)) {
 291                         case 0:                 f = 'C'; break;
 292                         case LLC_GSAP:          f = 'R'; break;
 293                         case LLC_IS_POLL:       f = 'P'; break;
 294                         case LLC_GSAP|LLC_IS_POLL: f = 'F'; break;
 295                         default:                f = '?'; break;
 296                 }
 297
 298                 if ((control & LLC_S_FMT) == LLC_S_FMT) {
 299                         static char *llc_s[] = { "rr", "rej", "rnr", "03" };
 300                         (void)printf("%s (r=%d,%c)",
 301                                 llc_s[LLC_S_CMD(control)],
 302                                 LLC_IS_NR(control),
 303                                 f);
 304                 } else {
 305                         (void)printf("I (s=%d,r=%d,%c)",
 306                                 LLC_I_NS(control),
 307                                 LLC_IS_NR(control),
 308                                 f);
 309                 }
 310                 p += 4;
 311                 length -= 4;
 312                 caplen -= 4;
 313         }
 314         (void)printf(" len=%d", length);
 315         return(1);
 316 }