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 1.32 2000-12-18 07:55:36 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                 ipx_print(p, length);
  85                 return (1);
  86         }
  87
  88         /* Cisco Discovery Protocol  - SNAP & ether type 0x2000 */
  89         if(llc.ssap == LLCSAP_SNAP && llc.dsap == LLCSAP_SNAP &&
  90                 llc.llcui == LLC_UI &&
  91                 llc.ethertype[0] == 0x20 && llc.ethertype[1] == 0x00 ) {
  92                     cdp_print( p, length, caplen, esrc, edst);
  93                     return (1);
  94         }
  95
  96         if (llc.ssap == LLCSAP_8021D && llc.dsap == LLCSAP_8021D) {
  97                 stp_print(p, length);
  98                 return (1);
  99         }
 100         if (llc.ssap == 0xf0 && llc.dsap == 0xf0
 101             && (!(llc.llcu & LLC_S_FMT) || llc.llcu == LLC_U_FMT)) {
 102                 /*
 103                  * we don't actually have a full netbeui parser yet, but the
 104                  * smb parser can handle many smb-in-netbeui packets, which
 105                  * is very useful, so we call that
 106                  *
 107                  * We don't call it for S frames, however, just I frames
 108                  * (which are frames that don't have the low-order bit,
 109                  * LLC_S_FMT, set in the first byte of the control field)
 110                  * and UI frames (whose control field is just 3, LLC_U_FMT).
 111                  */
 112
 113                 /*
 114                  * Skip the DSAP and LSAP.
 115                  */
 116                 p += 2;
 117                 length -= 2;
 118                 caplen -= 2;
 119
 120                 /*
 121                  * OK, what type of LLC frame is this?  The length
 122                  * of the control field depends on that - I frames
 123                  * have a two-byte control field, and U frames have
 124                  * a one-byte control field.
 125                  */
 126                 if (llc.llcu == LLC_U_FMT) {
 127                         control = llc.llcu;
 128                         p += 1;
 129                         length -= 1;
 130                         caplen -= 1;
 131                 } else {
 132                         /*
 133                          * The control field in I and S frames is
 134                          * little-endian.
 135                          */
 136                         control = EXTRACT_LE_16BITS(&llc.llcu);
 137                         p += 2;
 138                         length -= 2;
 139                         caplen -= 2;
 140                 }
 141                 netbeui_print(control, p, p + min(caplen, length));
 142                 return (1);
 143         }
 144         if (llc.ssap == LLCSAP_ISONS && llc.dsap == LLCSAP_ISONS
 145             && llc.llcui == LLC_UI) {
 146                 isoclns_print(p + 3, length - 3, caplen - 3, esrc, edst);
 147                 return (1);
 148         }
 149
 150         if (llc.ssap == LLCSAP_SNAP && llc.dsap == LLCSAP_SNAP
 151             && llc.llcui == LLC_UI) {
 152                 if (caplen < sizeof(llc)) {
 153                         (void)printf("[|llc-snap]");
 154                         default_print((u_char *)p, caplen);
 155                         return (0);
 156                 }
 157                 if (vflag)
 158                         (void)printf("snap %s ", protoid_string(llc.llcpi));
 159
 160                 caplen -= sizeof(llc);
 161                 length -= sizeof(llc);
 162                 p += sizeof(llc);
 163
 164                 /* This is an encapsulated Ethernet packet */
 165                 et = EXTRACT_16BITS(&llc.ethertype[0]);
 166                 ret = ether_encap_print(et, p, length, caplen,
 167                     extracted_ethertype);
 168                 if (ret)
 169                         return (ret);
 170         }
 171
 172         if ((llc.ssap & ~LLC_GSAP) == llc.dsap) {
 173                 if (eflag)
 174                         (void)printf("%s ", llcsap_string(llc.dsap));
 175                 else
 176                         (void)printf("%s > %s %s ",
 177                                         etheraddr_string(esrc),
 178                                         etheraddr_string(edst),
 179                                         llcsap_string(llc.dsap));
 180         } else {
 181                 if (eflag)
 182                         (void)printf("%s > %s ",
 183                                 llcsap_string(llc.ssap & ~LLC_GSAP),
 184                                 llcsap_string(llc.dsap));
 185                 else
 186                         (void)printf("%s %s > %s %s ",
 187                                 etheraddr_string(esrc),
 188                                 llcsap_string(llc.ssap & ~LLC_GSAP),
 189                                 etheraddr_string(edst),
 190                                 llcsap_string(llc.dsap));
 191         }
 192
 193         if ((llc.llcu & LLC_U_FMT) == LLC_U_FMT) {
 194                 u_int16_t cmd;
 195                 const char *m;
 196                 char f;
 197
 198                 cmd = LLC_U_CMD(llc.llcu);
 199                 m = tok2str(cmd2str, "%02x", cmd);
 200                 switch ((llc.ssap & LLC_GSAP) | (llc.llcu & LLC_U_POLL)) {
 201                         case 0:                 f = 'C'; break;
 202                         case LLC_GSAP:          f = 'R'; break;
 203                         case LLC_U_POLL:        f = 'P'; break;
 204                         case LLC_GSAP|LLC_U_POLL: f = 'F'; break;
 205                         default:                f = '?'; break;
 206                 }
 207
 208                 printf("%s/%c", m, f);
 209
 210                 p += 3;
 211                 length -= 3;
 212                 caplen -= 3;
 213
 214                 if ((llc.llcu & ~LLC_U_POLL) == LLC_XID) {
 215                         if (*p == LLC_XID_FI) {
 216                                 printf(": %02x %02x", p[1], p[2]);
 217                                 p += 3;
 218                                 length -= 3;
 219                                 caplen -= 3;
 220                         }
 221                 }
 222
 223                 if (cmd == LLC_UI && f == 'C') {
 224                         /*
 225                          * we don't have a proper ipx decoder yet, but there
 226                          * is a partial one in the smb code
 227                          */
 228                         ipx_netbios_print(p,p+min(caplen,length));
 229                 }
 230         } else {
 231                 char f;
 232
 233                 /*
 234                  * The control field in I and S frames is little-endian.
 235                  */
 236                 control = EXTRACT_LE_16BITS(&llc.llcu);
 237                 switch ((llc.ssap & LLC_GSAP) | (control & LLC_IS_POLL)) {
 238                         case 0:                 f = 'C'; break;
 239                         case LLC_GSAP:          f = 'R'; break;
 240                         case LLC_IS_POLL:       f = 'P'; break;
 241                         case LLC_GSAP|LLC_IS_POLL: f = 'F'; break;
 242                         default:                f = '?'; break;
 243                 }
 244
 245                 if ((control & LLC_S_FMT) == LLC_S_FMT) {
 246                         static char *llc_s[] = { "rr", "rej", "rnr", "03" };
 247                         (void)printf("%s (r=%d,%c)",
 248                                 llc_s[LLC_S_CMD(control)],
 249                                 LLC_IS_NR(control),
 250                                 f);
 251                 } else {
 252                         (void)printf("I (s=%d,r=%d,%c)",
 253                                 LLC_I_NS(control),
 254                                 LLC_IS_NR(control),
 255                                 f);
 256                 }
 257                 p += 4;
 258                 length -= 4;
 259                 caplen -= 4;
 260         }
 261         (void)printf(" len=%d", length);
 262         return(1);
 263 }