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 1.38 2001-06-04 05:47:14 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                 ipx_print(p, length);
  95                 return (1);
  96         }
  97
  98         if (llc.ssap == LLCSAP_8021D && llc.dsap == LLCSAP_8021D) {
  99                 stp_print(p, length);
 100                 return (1);
 101         }
 102
 103         if (llc.ssap == LLCSAP_IPX && llc.dsap == LLCSAP_IPX &&
 104             llc.llcui == LLC_UI) {
 105                 /*
 106                  * This is an Ethernet_802.2 IPX frame, with an 802.3
 107                  * header and an 802.2 LLC header with the source and
 108                  * destination SAPs being the IPX SAP.
 109                  *
 110                  * Skip DSAP, LSAP, and control field.
 111                  */
 112                 p += 3;
 113                 length -= 3;
 114                 caplen -= 3;
 115                 ipx_print(p, length);
 116                 return (1);
 117         }
 118
 119         if (llc.ssap == LLCSAP_NETBEUI && llc.dsap == LLCSAP_NETBEUI
 120             && (!(llc.llcu & LLC_S_FMT) || llc.llcu == LLC_U_FMT)) {
 121                 /*
 122                  * we don't actually have a full netbeui parser yet, but the
 123                  * smb parser can handle many smb-in-netbeui packets, which
 124                  * is very useful, so we call that
 125                  *
 126                  * We don't call it for S frames, however, just I frames
 127                  * (which are frames that don't have the low-order bit,
 128                  * LLC_S_FMT, set in the first byte of the control field)
 129                  * and UI frames (whose control field is just 3, LLC_U_FMT).
 130                  */
 131
 132                 /*
 133                  * Skip the DSAP and LSAP.
 134                  */
 135                 p += 2;
 136                 length -= 2;
 137                 caplen -= 2;
 138
 139                 /*
 140                  * OK, what type of LLC frame is this?  The length
 141                  * of the control field depends on that - I frames
 142                  * have a two-byte control field, and U frames have
 143                  * a one-byte control field.
 144                  */
 145                 if (llc.llcu == LLC_U_FMT) {
 146                         control = llc.llcu;
 147                         p += 1;
 148                         length -= 1;
 149                         caplen -= 1;
 150                 } else {
 151                         /*
 152                          * The control field in I and S frames is
 153                          * little-endian.
 154                          */
 155                         control = EXTRACT_LE_16BITS(&llc.llcu);
 156                         p += 2;
 157                         length -= 2;
 158                         caplen -= 2;
 159                 }
 160                 netbeui_print(control, p, length);
 161                 return (1);
 162         }
 163         if (llc.ssap == LLCSAP_ISONS && llc.dsap == LLCSAP_ISONS
 164             && llc.llcui == LLC_UI) {
 165                 isoclns_print(p + 3, length - 3, caplen - 3, esrc, edst);
 166                 return (1);
 167         }
 168
 169         if (llc.ssap == LLCSAP_SNAP && llc.dsap == LLCSAP_SNAP
 170             && llc.llcui == LLC_UI) {
 171                 u_int32_t orgcode;
 172
 173                 if (caplen < sizeof(llc)) {
 174                         (void)printf("[|llc-snap]");
 175                         default_print((u_char *)p, caplen);
 176                         return (0);
 177                 }
 178                 if (vflag)
 179                         (void)printf("snap %s ", protoid_string(llc.llcpi));
 180
 181                 caplen -= sizeof(llc);
 182                 length -= sizeof(llc);
 183                 p += sizeof(llc);
 184
 185                 orgcode = EXTRACT_24BITS(&llc.llc_orgcode[0]);
 186                 et = EXTRACT_16BITS(&llc.llc_ethertype[0]);
 187                 switch (orgcode) {
 188                 case OUI_ENCAP_ETHER:
 189                 case OUI_CISCO_90:
 190                         /*
 191                          * This is an encapsulated Ethernet packet,
 192                          * or a packet bridged by some piece of
 193                          * Cisco hardware; the protocol ID is
 194                          * an Ethernet protocol type.
 195                          */
 196                         ret = ether_encap_print(et, p, length, caplen,
 197                             extracted_ethertype);
 198                         if (ret)
 199                                 return (ret);
 200                         break;
 201
 202                 case OUI_APPLETALK:
 203                         if (et == ETHERTYPE_ATALK) {
 204                                 /*
 205                                  * No, I have no idea why Apple used one
 206                                  * of their own OUIs, rather than
 207                                  * 0x000000, and an Ethernet packet
 208                                  * type, for Appletalk data packets,
 209                                  * but used 0x000000 and an Ethernet
 210                                  * packet type for AARP packets.
 211                                  */
 212                                 ret = ether_encap_print(et, p, length, caplen,
 213                                     extracted_ethertype);
 214                                 if (ret)
 215                                         return (ret);
 216                         }
 217                         break;
 218
 219                 case OUI_CISCO:
 220                         if (et == ETHERTYPE_CISCO_CDP) {
 221                                 cdp_print( p, length, caplen, esrc, edst);
 222                                 return 1;
 223                         }
 224                         break;
 225                 }
 226         }
 227
 228         if ((llc.ssap & ~LLC_GSAP) == llc.dsap) {
 229                 if (eflag)
 230                         (void)printf("%s ", llcsap_string(llc.dsap));
 231                 else
 232                         (void)printf("%s > %s %s ",
 233                                         etheraddr_string(esrc),
 234                                         etheraddr_string(edst),
 235                                         llcsap_string(llc.dsap));
 236         } else {
 237                 if (eflag)
 238                         (void)printf("%s > %s ",
 239                                 llcsap_string(llc.ssap & ~LLC_GSAP),
 240                                 llcsap_string(llc.dsap));
 241                 else
 242                         (void)printf("%s %s > %s %s ",
 243                                 etheraddr_string(esrc),
 244                                 llcsap_string(llc.ssap & ~LLC_GSAP),
 245                                 etheraddr_string(edst),
 246                                 llcsap_string(llc.dsap));
 247         }
 248
 249         if ((llc.llcu & LLC_U_FMT) == LLC_U_FMT) {
 250                 u_int16_t cmd;
 251                 const char *m;
 252                 char f;
 253
 254                 cmd = LLC_U_CMD(llc.llcu);
 255                 m = tok2str(cmd2str, "%02x", cmd);
 256                 switch ((llc.ssap & LLC_GSAP) | (llc.llcu & LLC_U_POLL)) {
 257                         case 0:                 f = 'C'; break;
 258                         case LLC_GSAP:          f = 'R'; break;
 259                         case LLC_U_POLL:        f = 'P'; break;
 260                         case LLC_GSAP|LLC_U_POLL: f = 'F'; break;
 261                         default:                f = '?'; break;
 262                 }
 263
 264                 printf("%s/%c", m, f);
 265
 266                 p += 3;
 267                 length -= 3;
 268                 caplen -= 3;
 269
 270                 if ((llc.llcu & ~LLC_U_POLL) == LLC_XID) {
 271                         if (*p == LLC_XID_FI) {
 272                                 printf(": %02x %02x", p[1], p[2]);
 273                                 p += 3;
 274                                 length -= 3;
 275                                 caplen -= 3;
 276                         }
 277                 }
 278         } else {
 279                 char f;
 280
 281                 /*
 282                  * The control field in I and S frames is little-endian.
 283                  */
 284                 control = EXTRACT_LE_16BITS(&llc.llcu);
 285                 switch ((llc.ssap & LLC_GSAP) | (control & LLC_IS_POLL)) {
 286                         case 0:                 f = 'C'; break;
 287                         case LLC_GSAP:          f = 'R'; break;
 288                         case LLC_IS_POLL:       f = 'P'; break;
 289                         case LLC_GSAP|LLC_IS_POLL: f = 'F'; break;
 290                         default:                f = '?'; break;
 291                 }
 292
 293                 if ((control & LLC_S_FMT) == LLC_S_FMT) {
 294                         static char *llc_s[] = { "rr", "rej", "rnr", "03" };
 295                         (void)printf("%s (r=%d,%c)",
 296                                 llc_s[LLC_S_CMD(control)],
 297                                 LLC_IS_NR(control),
 298                                 f);
 299                 } else {
 300                         (void)printf("I (s=%d,r=%d,%c)",
 301                                 LLC_I_NS(control),
 302                                 LLC_IS_NR(control),
 303                                 f);
 304                 }
 305                 p += 4;
 306                 length -= 4;
 307                 caplen -= 4;
 308         }
 309         (void)printf(" len=%d", length);
 310         return(1);
 311 }