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 1.34 2001-01-15 03:24:00 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
  50 static struct tok cmd2str[] = {
  51         { LLC_UI,       "ui" },
  52         { LLC_TEST,     "test" },
  53         { LLC_XID,      "xid" },
  54         { LLC_UA,       "ua" },
  55         { LLC_DISC,     "disc" },
  56         { LLC_DM,       "dm" },
  57         { LLC_SABME,    "sabme" },
  58         { LLC_FRMR,     "frmr" },
  59         { 0,            NULL }
  60 };
  61
  62 /*
  63  * Returns non-zero IFF it succeeds in printing the header
  64  */
  65 int
  66 llc_print(const u_char *p, u_int length, u_int caplen,
  67           const u_char *esrc, const u_char *edst, u_short *extracted_ethertype)
  68 {
  69         struct llc llc;
  70         register u_short et;
  71         u_int16_t control;
  72         register int ret;
  73
  74         if (caplen < 3) {
  75                 (void)printf("[|llc]");
  76                 default_print((u_char *)p, caplen);
  77                 return(0);
  78         }
  79
  80         /* Watch out for possible alignment problems */
  81         memcpy((char *)&llc, (char *)p, min(caplen, sizeof(llc)));
  82
  83         if (llc.ssap == LLCSAP_GLOBAL && llc.dsap == LLCSAP_GLOBAL) {
  84                 /*
  85                  * This is an Ethernet_802.3 IPX frame; it has an
  86                  * 802.3 header (i.e., an Ethernet header where the
  87                  * type/length field is <= ETHERMTU, i.e. it's a length
  88                  * field, not a type field), but has no 802.2 header -
  89                  * the IPX packet starts right after the Ethernet header,
  90                  * with a signature of two bytes of 0xFF (which is
  91                  * LLCSAP_GLOBAL).
  92                  */
  93                 ipx_print(p, length);
  94                 return (1);
  95         }
  96
  97         /* Cisco Discovery Protocol  - SNAP & ether type 0x2000 */
  98         if(llc.ssap == LLCSAP_SNAP && llc.dsap == LLCSAP_SNAP &&
  99                 llc.llcui == LLC_UI &&
 100                 llc.ethertype[0] == 0x20 && llc.ethertype[1] == 0x00 ) {
 101                     cdp_print( p, length, caplen, esrc, edst);
 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_IPX && llc.dsap == LLCSAP_IPX &&
 111             llc.llcui == LLC_UI) {
 112                 /*
 113                  * This is an Ethernet_802.2 IPX frame, with an 802.3
 114                  * header and an 802.2 LLC header with the source and
 115                  * destination SAPs being the IPX SAP.
 116                  *
 117                  * Skip DSAP, LSAP, and control field.
 118                  */
 119                 p += 3;
 120                 length -= 3;
 121                 caplen -= 3;
 122                 ipx_print(p, length);
 123                 return (1);
 124         }
 125
 126         if (llc.ssap == 0xf0 && llc.dsap == 0xf0
 127             && (!(llc.llcu & LLC_S_FMT) || llc.llcu == LLC_U_FMT)) {
 128                 /*
 129                  * we don't actually have a full netbeui parser yet, but the
 130                  * smb parser can handle many smb-in-netbeui packets, which
 131                  * is very useful, so we call that
 132                  *
 133                  * We don't call it for S frames, however, just I frames
 134                  * (which are frames that don't have the low-order bit,
 135                  * LLC_S_FMT, set in the first byte of the control field)
 136                  * and UI frames (whose control field is just 3, LLC_U_FMT).
 137                  */
 138
 139                 /*
 140                  * Skip the DSAP and LSAP.
 141                  */
 142                 p += 2;
 143                 length -= 2;
 144                 caplen -= 2;
 145
 146                 /*
 147                  * OK, what type of LLC frame is this?  The length
 148                  * of the control field depends on that - I frames
 149                  * have a two-byte control field, and U frames have
 150                  * a one-byte control field.
 151                  */
 152                 if (llc.llcu == LLC_U_FMT) {
 153                         control = llc.llcu;
 154                         p += 1;
 155                         length -= 1;
 156                         caplen -= 1;
 157                 } else {
 158                         /*
 159                          * The control field in I and S frames is
 160                          * little-endian.
 161                          */
 162                         control = EXTRACT_LE_16BITS(&llc.llcu);
 163                         p += 2;
 164                         length -= 2;
 165                         caplen -= 2;
 166                 }
 167                 netbeui_print(control, p, p + min(caplen, length));
 168                 return (1);
 169         }
 170         if (llc.ssap == LLCSAP_ISONS && llc.dsap == LLCSAP_ISONS
 171             && llc.llcui == LLC_UI) {
 172                 isoclns_print(p + 3, length - 3, caplen - 3, esrc, edst);
 173                 return (1);
 174         }
 175
 176         if (llc.ssap == LLCSAP_SNAP && llc.dsap == LLCSAP_SNAP
 177             && llc.llcui == LLC_UI) {
 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                 /* This is an encapsulated Ethernet packet */
 191                 et = EXTRACT_16BITS(&llc.ethertype[0]);
 192                 ret = ether_encap_print(et, p, length, caplen,
 193                     extracted_ethertype);
 194                 if (ret)
 195                         return (ret);
 196         }
 197
 198         if ((llc.ssap & ~LLC_GSAP) == llc.dsap) {
 199                 if (eflag)
 200                         (void)printf("%s ", llcsap_string(llc.dsap));
 201                 else
 202                         (void)printf("%s > %s %s ",
 203                                         etheraddr_string(esrc),
 204                                         etheraddr_string(edst),
 205                                         llcsap_string(llc.dsap));
 206         } else {
 207                 if (eflag)
 208                         (void)printf("%s > %s ",
 209                                 llcsap_string(llc.ssap & ~LLC_GSAP),
 210                                 llcsap_string(llc.dsap));
 211                 else
 212                         (void)printf("%s %s > %s %s ",
 213                                 etheraddr_string(esrc),
 214                                 llcsap_string(llc.ssap & ~LLC_GSAP),
 215                                 etheraddr_string(edst),
 216                                 llcsap_string(llc.dsap));
 217         }
 218
 219         if ((llc.llcu & LLC_U_FMT) == LLC_U_FMT) {
 220                 u_int16_t cmd;
 221                 const char *m;
 222                 char f;
 223
 224                 cmd = LLC_U_CMD(llc.llcu);
 225                 m = tok2str(cmd2str, "%02x", cmd);
 226                 switch ((llc.ssap & LLC_GSAP) | (llc.llcu & LLC_U_POLL)) {
 227                         case 0:                 f = 'C'; break;
 228                         case LLC_GSAP:          f = 'R'; break;
 229                         case LLC_U_POLL:        f = 'P'; break;
 230                         case LLC_GSAP|LLC_U_POLL: f = 'F'; break;
 231                         default:                f = '?'; break;
 232                 }
 233
 234                 printf("%s/%c", m, f);
 235
 236                 p += 3;
 237                 length -= 3;
 238                 caplen -= 3;
 239
 240                 if ((llc.llcu & ~LLC_U_POLL) == LLC_XID) {
 241                         if (*p == LLC_XID_FI) {
 242                                 printf(": %02x %02x", p[1], p[2]);
 243                                 p += 3;
 244                                 length -= 3;
 245                                 caplen -= 3;
 246                         }
 247                 }
 248         } else {
 249                 char f;
 250
 251                 /*
 252                  * The control field in I and S frames is little-endian.
 253                  */
 254                 control = EXTRACT_LE_16BITS(&llc.llcu);
 255                 switch ((llc.ssap & LLC_GSAP) | (control & LLC_IS_POLL)) {
 256                         case 0:                 f = 'C'; break;
 257                         case LLC_GSAP:          f = 'R'; break;
 258                         case LLC_IS_POLL:       f = 'P'; break;
 259                         case LLC_GSAP|LLC_IS_POLL: f = 'F'; break;
 260                         default:                f = '?'; break;
 261                 }
 262
 263                 if ((control & LLC_S_FMT) == LLC_S_FMT) {
 264                         static char *llc_s[] = { "rr", "rej", "rnr", "03" };
 265                         (void)printf("%s (r=%d,%c)",
 266                                 llc_s[LLC_S_CMD(control)],
 267                                 LLC_IS_NR(control),
 268                                 f);
 269                 } else {
 270                         (void)printf("I (s=%d,r=%d,%c)",
 271                                 LLC_I_NS(control),
 272                                 LLC_IS_NR(control),
 273                                 f);
 274                 }
 275                 p += 4;
 276                 length -= 4;
 277                 caplen -= 4;
 278         }
 279         (void)printf(" len=%d", length);
 280         return(1);
 281 }