packet-ethertype.c

   1 /* ethertype.c
   2  * Routines for calling the right protocol for the ethertype.
   3  *
   4  * $Id: packet-ethertype.c,v 1.28 2002/04/24 06:03:33 guy Exp $
   5  *
   6  * Gilbert Ramirez <gram@alumni.rice.edu>
   7  *
   8  * Ethereal - Network traffic analyzer
   9  * By Gerald Combs <gerald@ethereal.com>
  10  * Copyright 1998 Gerald Combs
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License
  14  * as published by the Free Software Foundation; either version 2
  15  * of the License, or (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software
  24  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  25  */
  26
  27 #ifdef HAVE_CONFIG_H
  28 # include "config.h"
  29 #endif
  30
  31 #ifdef HAVE_SYS_TYPES_H
  32 # include <sys/types.h>
  33 #endif
  34
  35 #include <glib.h>
  36 #include <epan/packet.h>
  37 #include "packet-ip.h"
  38 #include "packet-ipx.h"
  39 #include "packet-vlan.h"
  40 #include "packet-vines.h"
  41 #include "etypes.h"
  42 #include "ppptypes.h"
  43
  44 static dissector_table_t ethertype_dissector_table;
  45
  46 static dissector_handle_t data_handle;
  47
  48 const value_string etype_vals[] = {
  49     {ETHERTYPE_IP,              "IP"                            },
  50     {ETHERTYPE_IPv6,            "IPv6"                          },
  51     {ETHERTYPE_X25L3,           "X.25 Layer 3"                  },
  52     {ETHERTYPE_ARP,             "ARP"                           },
  53     {ETHERTYPE_REVARP,          "RARP"                          },
  54     {ETHERTYPE_DEC_LB,          "DEC LanBridge"                 },
  55     {ETHERTYPE_ATALK,           "Appletalk"                     },
  56     {ETHERTYPE_SNA,             "SNA-over-Ethernet"             },
  57     {ETHERTYPE_AARP,            "AARP"                          },
  58     {ETHERTYPE_IPX,             "Netware IPX/SPX"               },
  59     {ETHERTYPE_VINES,           "Vines"                         },
  60     {ETHERTYPE_TRAIN,           "Netmon Train"                  },
  61     {ETHERTYPE_LOOP,            "Loopback"                      }, /* Ethernet Loopback */
  62     {ETHERTYPE_WCP,             "Wellfleet Compression Protocol" },
  63     {ETHERTYPE_PPPOED,          "PPPoE Discovery"               },
  64     {ETHERTYPE_PPPOES,          "PPPoE Session"                 },
  65     {ETHERTYPE_VLAN,            "802.1Q Virtual LAN"            },
  66     {ETHERTYPE_EAPOL,           "802.1X Authentication"         },
  67     {ETHERTYPE_MPLS,            "MPLS label switched packet"    },
  68     {ETHERTYPE_MPLS_MULTI,      "MPLS multicast label switched packet" },
  69     {ETHERTYPE_3C_NBP_DGRAM,    "3Com NBP Datagram"             },
  70     {ETHERTYPE_DEC,             "DEC proto"                     },
  71     {ETHERTYPE_DNA_DL,          "DEC DNA Dump/Load"             },
  72     {ETHERTYPE_DNA_RC,          "DEC DNA Remote Console"        },
  73     {ETHERTYPE_DNA_RT,          "DEC DNA Routing"               },
  74     {ETHERTYPE_LAT,             "DEC LAT"                       },
  75     {ETHERTYPE_DEC_DIAG,        "DEC Diagnostics"               },
  76     {ETHERTYPE_DEC_CUST,        "DEC Customer use"              },
  77     {ETHERTYPE_DEC_SCA,         "DEC LAVC/SCA"                  },
  78     {ETHERTYPE_ETHBRIDGE,       "Transparent Ethernet bridging" },
  79     {ETHERTYPE_CGMP,            "Cisco Group Management Protocol" },
  80
  81     /*
  82      * NDISWAN on Windows translates Ethernet frames from higher-level
  83      * protocols into PPP frames to hand to the PPP driver, and translates
  84      * PPP frames from the PPP driver to hand to the higher-level protocols.
  85      *
  86      * Apparently the PPP driver, on at least some versions of Windows,
  87      * passes frames for internal-to-PPP protocols up through NDISWAN;
  88      * the protocol type field appears to be passed through unchanged
  89      * (unlike what's done with, for example, the protocol type field
  90      * for IP, which is mapped from its PPP value to its Ethernet value).
  91      *
  92      * This means that we may see, on Ethernet captures, frames for
  93      * protocols internal to PPP, so we list as "Ethernet" protocol
  94      * types the PPP protocol types we've seen.
  95      */
  96     {PPP_IPCP,                  "PPP IP Control Protocol" },
  97     {PPP_LCP,                   "PPP Link Control Protocol" },
  98     {PPP_PAP,                   "PPP Password Authentication Protocol" },
  99     {PPP_CCP,                   "PPP Compression Control Protocol" },
 100     {0,                         NULL                            } };
 101
 102 static void add_trailer(proto_tree *fh_tree, int trailer_id, tvbuff_t *tvb,
 103     tvbuff_t *next_tvb, int offset_after_etype, guint length_before);
 104
 105 void
 106 capture_ethertype(guint16 etype, const u_char *pd, int offset, int len,
 107                   packet_counts *ld)
 108 {
 109   switch (etype) {
 110     case ETHERTYPE_IP:
 111       capture_ip(pd, offset, len, ld);
 112       break;
 113     case ETHERTYPE_IPX:
 114       capture_ipx(ld);
 115       break;
 116     case ETHERTYPE_VLAN:
 117       capture_vlan(pd, offset, len, ld);
 118       break;
 119     case ETHERTYPE_VINES:
 120       capture_vines(ld);
 121       break;
 122     default:
 123       ld->other++;
 124       break;
 125   }
 126 }
 127
 128 void
 129 ethertype(guint16 etype, tvbuff_t *tvb, int offset_after_etype,
 130                 packet_info *pinfo, proto_tree *tree, proto_tree *fh_tree,
 131                 int etype_id, int trailer_id)
 132 {
 133         char                    *description;
 134         tvbuff_t                *next_tvb;
 135         guint                   length_before;
 136         volatile gboolean       dissector_found;
 137
 138         /* Add to proto_tree */
 139         if (tree) {
 140                 proto_tree_add_uint(fh_tree, etype_id, tvb,
 141                     offset_after_etype - 2, 2, etype);
 142         }
 143
 144         /* Tvbuff for the payload after the Ethernet type. */
 145         next_tvb = tvb_new_subset(tvb, offset_after_etype, -1, -1);
 146
 147         pinfo->ethertype = etype;
 148
 149         /* Remember how much data there is in it. */
 150         length_before = tvb_reported_length(next_tvb);
 151
 152         /* Look for sub-dissector, and call it if found.
 153            Catch BoundsError and ReportedBoundsError, so that if the
 154            reported length of "next_tvb" was reduced by some dissector
 155            before an exception was thrown, we can still put in an item
 156            for the trailer. */
 157         TRY {
 158                 dissector_found = dissector_try_port(ethertype_dissector_table,
 159                     etype, next_tvb, pinfo, tree);
 160         }
 161         CATCH2(BoundsError, ReportedBoundsError) {
 162                 /* Well, somebody threw an exception; that means that a
 163                    dissector was found, so we don't need to dissect
 164                    the payload as data or update the protocol or info
 165                    columns. */
 166                 dissector_found = TRUE;
 167
 168                 /* Add the trailer, if appropriate. */
 169                 add_trailer(fh_tree, trailer_id, tvb, next_tvb,
 170                     offset_after_etype, length_before);
 171
 172                 /* Rrethrow the exception, so the "Short Frame" or "Mangled
 173                    Frame" indication can be put into the tree. */
 174                 RETHROW;
 175
 176                 /* XXX - RETHROW shouldn't return. */
 177                 g_assert_not_reached();
 178         }
 179         ENDTRY;
 180
 181         if (!dissector_found) {
 182                 /* No sub-dissector found.
 183                    Label rest of packet as "Data" */
 184                 call_dissector(data_handle,next_tvb, pinfo, tree);
 185
 186                 /* Label protocol */
 187                 switch (etype) {
 188
 189                 case ETHERTYPE_LOOP:
 190                         if (check_col(pinfo->cinfo, COL_PROTOCOL)) {
 191                                 col_add_fstr(pinfo->cinfo, COL_PROTOCOL, "LOOP");
 192                         }
 193                         break;
 194
 195                 default:
 196                         if (check_col(pinfo->cinfo, COL_PROTOCOL)) {
 197                                 col_add_fstr(pinfo->cinfo, COL_PROTOCOL, "0x%04x",
 198                                     etype);
 199                         }
 200                         break;
 201                 }
 202                 if (check_col(pinfo->cinfo, COL_INFO)) {
 203                         description = match_strval(etype, etype_vals);
 204                         if (description) {
 205                                 col_add_fstr(pinfo->cinfo, COL_INFO, "%s",
 206                                     description);
 207                         }
 208                 }
 209         }
 210
 211         add_trailer(fh_tree, trailer_id, tvb, next_tvb, offset_after_etype,
 212             length_before);
 213 }
 214
 215 static void
 216 add_trailer(proto_tree *fh_tree, int trailer_id, tvbuff_t *tvb,
 217     tvbuff_t *next_tvb, int offset_after_etype, guint length_before)
 218 {
 219         guint           length;
 220         tvbuff_t        *volatile trailer_tvb;
 221
 222         if (fh_tree == NULL)
 223                 return; /* we're not building a protocol tree */
 224
 225         if (trailer_id == -1)
 226                 return; /* our caller doesn't care about trailers */
 227
 228         /* OK, how much is there in that tvbuff now? */
 229         length = tvb_reported_length(next_tvb);
 230
 231         /* If there's less than there was before, what's left is
 232            a trailer. */
 233         if (length < length_before) {
 234                 /*
 235                  * Create a tvbuff for the padding.
 236                  */
 237                 TRY {
 238                         trailer_tvb = tvb_new_subset(tvb,
 239                             offset_after_etype + length, -1, -1);
 240                 }
 241                 CATCH2(BoundsError, ReportedBoundsError) {
 242                         /* The packet doesn't have "length" bytes worth of
 243                            captured data left in it.  No trailer to display. */
 244                         trailer_tvb = NULL;
 245                 }
 246                 ENDTRY;
 247         } else
 248                 trailer_tvb = NULL;     /* no trailer */
 249
 250         /* If there's some bytes left over, and we were given an item ID
 251            for a trailer, mark those bytes as a trailer. */
 252         if (trailer_tvb) {
 253                 guint   trailer_length;
 254
 255                 trailer_length = tvb_length(trailer_tvb);
 256                 if (trailer_length != 0) {
 257                         proto_tree_add_item(fh_tree, trailer_id, trailer_tvb, 0,
 258                             trailer_length, FALSE);
 259                 }
 260         }
 261 }
 262
 263
 264 void
 265 proto_register_ethertype(void)
 266 {
 267         /* subdissector code */
 268         ethertype_dissector_table = register_dissector_table("ethertype",
 269             "Ethertype", FT_UINT16, BASE_HEX);
 270 }
 271
 272 void
 273 proto_reg_handoff_ethertype(void){
 274   data_handle = find_dissector("data");
 275 }