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 1.43 2001-10-08 21:25:22 fenner 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 #ifdef TCPDUMP_DO_SMB
 125         if (llc.ssap == LLCSAP_NETBEUI && llc.dsap == LLCSAP_NETBEUI
 126             && (!(llc.llcu & LLC_S_FMT) || llc.llcu == LLC_U_FMT)) {
 127                 /*
 128                  * we don't actually have a full netbeui parser yet, but the
 129                  * smb parser can handle many smb-in-netbeui packets, which
 130                  * is very useful, so we call that
 131                  *
 132                  * We don't call it for S frames, however, just I frames
 133                  * (which are frames that don't have the low-order bit,
 134                  * LLC_S_FMT, set in the first byte of the control field)
 135                  * and UI frames (whose control field is just 3, LLC_U_FMT).
 136                  */
 137
 138                 /*
 139                  * Skip the DSAP and LSAP.
 140                  */
 141                 p += 2;
 142                 length -= 2;
 143                 caplen -= 2;
 144
 145                 /*
 146                  * OK, what type of LLC frame is this?  The length
 147                  * of the control field depends on that - I frames
 148                  * have a two-byte control field, and U frames have
 149                  * a one-byte control field.
 150                  */
 151                 if (llc.llcu == LLC_U_FMT) {
 152                         control = llc.llcu;
 153                         p += 1;
 154                         length -= 1;
 155                         caplen -= 1;
 156                 } else {
 157                         /*
 158                          * The control field in I and S frames is
 159                          * little-endian.
 160                          */
 161                         control = EXTRACT_LE_16BITS(&llc.llcu);
 162                         p += 2;
 163                         length -= 2;
 164                         caplen -= 2;
 165                 }
 166                 netbeui_print(control, p, length);
 167                 return (1);
 168         }
 169 #endif
 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                 u_int32_t orgcode;
 179
 180                 if (caplen < sizeof(llc)) {
 181                         (void)printf("[|llc-snap]");
 182                         default_print((u_char *)p, caplen);
 183                         return (0);
 184                 }
 185                 if (vflag)
 186                         (void)printf("snap %s ", protoid_string(llc.llcpi));
 187
 188                 caplen -= sizeof(llc);
 189                 length -= sizeof(llc);
 190                 p += sizeof(llc);
 191
 192                 orgcode = EXTRACT_24BITS(&llc.llc_orgcode[0]);
 193                 et = EXTRACT_16BITS(&llc.llc_ethertype[0]);
 194                 switch (orgcode) {
 195                 case OUI_ENCAP_ETHER:
 196                 case OUI_CISCO_90:
 197                         /*
 198                          * This is an encapsulated Ethernet packet,
 199                          * or a packet bridged by some piece of
 200                          * Cisco hardware; the protocol ID is
 201                          * an Ethernet protocol type.
 202                          */
 203                         ret = ether_encap_print(et, p, length, caplen,
 204                             extracted_ethertype);
 205                         if (ret)
 206                                 return (ret);
 207                         break;
 208
 209                 case OUI_APPLETALK:
 210                         if (et == ETHERTYPE_ATALK) {
 211                                 /*
 212                                  * No, I have no idea why Apple used one
 213                                  * of their own OUIs, rather than
 214                                  * 0x000000, and an Ethernet packet
 215                                  * type, for Appletalk data packets,
 216                                  * but used 0x000000 and an Ethernet
 217                                  * packet type for AARP packets.
 218                                  */
 219                                 ret = ether_encap_print(et, p, length, caplen,
 220                                     extracted_ethertype);
 221                                 if (ret)
 222                                         return (ret);
 223                         }
 224                         break;
 225
 226                 case OUI_CISCO:
 227                         if (et == ETHERTYPE_CISCO_CDP) {
 228                                 cdp_print(p, length, caplen, esrc, edst);
 229                                 return 1;
 230                         }
 231                         break;
 232                 }
 233         }
 234
 235         if ((llc.ssap & ~LLC_GSAP) == llc.dsap) {
 236                 if (eflag || esrc == NULL || edst == NULL)
 237                         (void)printf("%s ", llcsap_string(llc.dsap));
 238                 else
 239                         (void)printf("%s > %s %s ",
 240                                         etheraddr_string(esrc),
 241                                         etheraddr_string(edst),
 242                                         llcsap_string(llc.dsap));
 243         } else {
 244                 if (eflag || esrc == NULL || edst == NULL)
 245                         (void)printf("%s > %s ",
 246                                 llcsap_string(llc.ssap & ~LLC_GSAP),
 247                                 llcsap_string(llc.dsap));
 248                 else
 249                         (void)printf("%s %s > %s %s ",
 250                                 etheraddr_string(esrc),
 251                                 llcsap_string(llc.ssap & ~LLC_GSAP),
 252                                 etheraddr_string(edst),
 253                                 llcsap_string(llc.dsap));
 254         }
 255
 256         if ((llc.llcu & LLC_U_FMT) == LLC_U_FMT) {
 257                 u_int16_t cmd;
 258                 const char *m;
 259                 char f;
 260
 261                 cmd = LLC_U_CMD(llc.llcu);
 262                 m = tok2str(cmd2str, "%02x", cmd);
 263                 switch ((llc.ssap & LLC_GSAP) | (llc.llcu & LLC_U_POLL)) {
 264                         case 0:                 f = 'C'; break;
 265                         case LLC_GSAP:          f = 'R'; break;
 266                         case LLC_U_POLL:        f = 'P'; break;
 267                         case LLC_GSAP|LLC_U_POLL: f = 'F'; break;
 268                         default:                f = '?'; break;
 269                 }
 270
 271                 printf("%s/%c", m, f);
 272
 273                 p += 3;
 274                 length -= 3;
 275                 caplen -= 3;
 276
 277                 if ((llc.llcu & ~LLC_U_POLL) == LLC_XID) {
 278                         if (*p == LLC_XID_FI) {
 279                                 printf(": %02x %02x", p[1], p[2]);
 280                                 p += 3;
 281                                 length -= 3;
 282                                 caplen -= 3;
 283                         }
 284                 }
 285         } else {
 286                 char f;
 287
 288                 /*
 289                  * The control field in I and S frames is little-endian.
 290                  */
 291                 control = EXTRACT_LE_16BITS(&llc.llcu);
 292                 switch ((llc.ssap & LLC_GSAP) | (control & LLC_IS_POLL)) {
 293                         case 0:                 f = 'C'; break;
 294                         case LLC_GSAP:          f = 'R'; break;
 295                         case LLC_IS_POLL:       f = 'P'; break;
 296                         case LLC_GSAP|LLC_IS_POLL: f = 'F'; break;
 297                         default:                f = '?'; break;
 298                 }
 299
 300                 if ((control & LLC_S_FMT) == LLC_S_FMT) {
 301                         static char *llc_s[] = { "rr", "rej", "rnr", "03" };
 302                         (void)printf("%s (r=%d,%c)",
 303                                 llc_s[LLC_S_CMD(control)],
 304                                 LLC_IS_NR(control),
 305                                 f);
 306                 } else {
 307                         (void)printf("I (s=%d,r=%d,%c)",
 308                                 LLC_I_NS(control),
 309                                 LLC_IS_NR(control),
 310                                 f);
 311                 }
 312                 p += 4;
 313                 length -= 4;
 314                 caplen -= 4;
 315         }
 316         (void)printf(" len=%d", length);
 317         return(1);
 318 }