packet-ethertype.c

   1 /* ethertype.c
   2  * Routines for calling the right protocol for the ethertype.
   3  *
   4  * $Id: packet-ethertype.c,v 1.29 2002/06/13 07:18:47 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     {ETHERTYPE_SLOW_PROTOCOLS,  "Slow Protocols"                },
  81
  82     /*
  83      * NDISWAN on Windows translates Ethernet frames from higher-level
  84      * protocols into PPP frames to hand to the PPP driver, and translates
  85      * PPP frames from the PPP driver to hand to the higher-level protocols.
  86      *
  87      * Apparently the PPP driver, on at least some versions of Windows,
  88      * passes frames for internal-to-PPP protocols up through NDISWAN;
  89      * the protocol type field appears to be passed through unchanged
  90      * (unlike what's done with, for example, the protocol type field
  91      * for IP, which is mapped from its PPP value to its Ethernet value).
  92      *
  93      * This means that we may see, on Ethernet captures, frames for
  94      * protocols internal to PPP, so we list as "Ethernet" protocol
  95      * types the PPP protocol types we've seen.
  96      */
  97     {PPP_IPCP,                  "PPP IP Control Protocol" },
  98     {PPP_LCP,                   "PPP Link Control Protocol" },
  99     {PPP_PAP,                   "PPP Password Authentication Protocol" },
 100     {PPP_CCP,                   "PPP Compression Control Protocol" },
 101     {0,                         NULL                            } };
 102
 103 static void add_trailer(proto_tree *fh_tree, int trailer_id, tvbuff_t *tvb,
 104     tvbuff_t *next_tvb, int offset_after_etype, guint length_before);
 105
 106 void
 107 capture_ethertype(guint16 etype, const u_char *pd, int offset, int len,
 108                   packet_counts *ld)
 109 {
 110   switch (etype) {
 111     case ETHERTYPE_IP:
 112       capture_ip(pd, offset, len, ld);
 113       break;
 114     case ETHERTYPE_IPX:
 115       capture_ipx(ld);
 116       break;
 117     case ETHERTYPE_VLAN:
 118       capture_vlan(pd, offset, len, ld);
 119       break;
 120     case ETHERTYPE_VINES:
 121       capture_vines(ld);
 122       break;
 123     default:
 124       ld->other++;
 125       break;
 126   }
 127 }
 128
 129 void
 130 ethertype(guint16 etype, tvbuff_t *tvb, int offset_after_etype,
 131                 packet_info *pinfo, proto_tree *tree, proto_tree *fh_tree,
 132                 int etype_id, int trailer_id)
 133 {
 134         char                    *description;
 135         tvbuff_t                *next_tvb;
 136         guint                   length_before;
 137         volatile gboolean       dissector_found;
 138
 139         /* Add to proto_tree */
 140         if (tree) {
 141                 proto_tree_add_uint(fh_tree, etype_id, tvb,
 142                     offset_after_etype - 2, 2, etype);
 143         }
 144
 145         /* Tvbuff for the payload after the Ethernet type. */
 146         next_tvb = tvb_new_subset(tvb, offset_after_etype, -1, -1);
 147
 148         pinfo->ethertype = etype;
 149
 150         /* Remember how much data there is in it. */
 151         length_before = tvb_reported_length(next_tvb);
 152
 153         /* Look for sub-dissector, and call it if found.
 154            Catch BoundsError and ReportedBoundsError, so that if the
 155            reported length of "next_tvb" was reduced by some dissector
 156            before an exception was thrown, we can still put in an item
 157            for the trailer. */
 158         TRY {
 159                 dissector_found = dissector_try_port(ethertype_dissector_table,
 160                     etype, next_tvb, pinfo, tree);
 161         }
 162         CATCH2(BoundsError, ReportedBoundsError) {
 163                 /* Well, somebody threw an exception; that means that a
 164                    dissector was found, so we don't need to dissect
 165                    the payload as data or update the protocol or info
 166                    columns. */
 167                 dissector_found = TRUE;
 168
 169                 /* Add the trailer, if appropriate. */
 170                 add_trailer(fh_tree, trailer_id, tvb, next_tvb,
 171                     offset_after_etype, length_before);
 172
 173                 /* Rrethrow the exception, so the "Short Frame" or "Mangled
 174                    Frame" indication can be put into the tree. */
 175                 RETHROW;
 176
 177                 /* XXX - RETHROW shouldn't return. */
 178                 g_assert_not_reached();
 179         }
 180         ENDTRY;
 181
 182         if (!dissector_found) {
 183                 /* No sub-dissector found.
 184                    Label rest of packet as "Data" */
 185                 call_dissector(data_handle,next_tvb, pinfo, tree);
 186
 187                 /* Label protocol */
 188                 switch (etype) {
 189
 190                 case ETHERTYPE_LOOP:
 191                         if (check_col(pinfo->cinfo, COL_PROTOCOL)) {
 192                                 col_add_fstr(pinfo->cinfo, COL_PROTOCOL, "LOOP");
 193                         }
 194                         break;
 195
 196                 default:
 197                         if (check_col(pinfo->cinfo, COL_PROTOCOL)) {
 198                                 col_add_fstr(pinfo->cinfo, COL_PROTOCOL, "0x%04x",
 199                                     etype);
 200                         }
 201                         break;
 202                 }
 203                 if (check_col(pinfo->cinfo, COL_INFO)) {
 204                         description = match_strval(etype, etype_vals);
 205                         if (description) {
 206                                 col_add_fstr(pinfo->cinfo, COL_INFO, "%s",
 207                                     description);
 208                         }
 209                 }
 210         }
 211
 212         add_trailer(fh_tree, trailer_id, tvb, next_tvb, offset_after_etype,
 213             length_before);
 214 }
 215
 216 static void
 217 add_trailer(proto_tree *fh_tree, int trailer_id, tvbuff_t *tvb,
 218     tvbuff_t *next_tvb, int offset_after_etype, guint length_before)
 219 {
 220         guint           length;
 221         tvbuff_t        *volatile trailer_tvb;
 222
 223         if (fh_tree == NULL)
 224                 return; /* we're not building a protocol tree */
 225
 226         if (trailer_id == -1)
 227                 return; /* our caller doesn't care about trailers */
 228
 229         /* OK, how much is there in that tvbuff now? */
 230         length = tvb_reported_length(next_tvb);
 231
 232         /* If there's less than there was before, what's left is
 233            a trailer. */
 234         if (length < length_before) {
 235                 /*
 236                  * Create a tvbuff for the padding.
 237                  */
 238                 TRY {
 239                         trailer_tvb = tvb_new_subset(tvb,
 240                             offset_after_etype + length, -1, -1);
 241                 }
 242                 CATCH2(BoundsError, ReportedBoundsError) {
 243                         /* The packet doesn't have "length" bytes worth of
 244                            captured data left in it.  No trailer to display. */
 245                         trailer_tvb = NULL;
 246                 }
 247                 ENDTRY;
 248         } else
 249                 trailer_tvb = NULL;     /* no trailer */
 250
 251         /* If there's some bytes left over, and we were given an item ID
 252            for a trailer, mark those bytes as a trailer. */
 253         if (trailer_tvb) {
 254                 guint   trailer_length;
 255
 256                 trailer_length = tvb_length(trailer_tvb);
 257                 if (trailer_length != 0) {
 258                         proto_tree_add_item(fh_tree, trailer_id, trailer_tvb, 0,
 259                             trailer_length, FALSE);
 260                 }
 261         }
 262 }
 263
 264
 265 void
 266 proto_register_ethertype(void)
 267 {
 268         /* subdissector code */
 269         ethertype_dissector_table = register_dissector_table("ethertype",
 270             "Ethertype", FT_UINT16, BASE_HEX);
 271 }
 272
 273 void
 274 proto_reg_handoff_ethertype(void){
 275   data_handle = find_dissector("data");
 276 }