packet-ethertype.c

   1 /* ethertype.c
   2  * Routines for calling the right protocol for the ethertype.
   3  *
   4  * $Id: packet-ethertype.c,v 1.37 2003/08/21 21:05:29 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 #include <glib.h>
  32 #include <epan/packet.h>
  33 #include "packet-eth.h"
  34 #include "packet-ip.h"
  35 #include "packet-ipv6.h"
  36 #include "packet-ipx.h"
  37 #include "packet-vlan.h"
  38 #include "packet-vines.h"
  39 #include "etypes.h"
  40 #include "ppptypes.h"
  41
  42 static dissector_table_t ethertype_dissector_table;
  43
  44 static dissector_handle_t data_handle;
  45
  46 const value_string etype_vals[] = {
  47     {ETHERTYPE_IP,              "IP"                            },
  48     {ETHERTYPE_IPv6,            "IPv6"                          },
  49     {ETHERTYPE_X25L3,           "X.25 Layer 3"                  },
  50     {ETHERTYPE_ARP,             "ARP"                           },
  51     {ETHERTYPE_REVARP,          "RARP"                          },
  52     {ETHERTYPE_DEC_LB,          "DEC LanBridge"                 },
  53     {ETHERTYPE_ATALK,           "Appletalk"                     },
  54     {ETHERTYPE_SNA,             "SNA-over-Ethernet"             },
  55     {ETHERTYPE_AARP,            "AARP"                          },
  56     {ETHERTYPE_IPX,             "Netware IPX/SPX"               },
  57     {ETHERTYPE_VINES_IP,        "Vines IP"                      },
  58     {ETHERTYPE_VINES_ECHO,      "Vines Echo"                    },
  59     {ETHERTYPE_TRAIN,           "Netmon Train"                  },
  60     {ETHERTYPE_LOOP,            "Loopback"                      }, /* Ethernet Loopback */
  61     {ETHERTYPE_WCP,             "Wellfleet Compression Protocol" },
  62     {ETHERTYPE_PPPOED,          "PPPoE Discovery"               },
  63     {ETHERTYPE_PPPOES,          "PPPoE Session"                 },
  64     {ETHERTYPE_INTEL_ANS,       "Intel ANS probe"               },
  65     {ETHERTYPE_MS_NLB_HEARTBEAT,        "MS NLB heartbeat"      },
  66     {ETHERTYPE_VLAN,            "802.1Q Virtual LAN"            },
  67     {ETHERTYPE_EAPOL,           "802.1X Authentication"         },
  68     {ETHERTYPE_MPLS,            "MPLS label switched packet"    },
  69     {ETHERTYPE_MPLS_MULTI,      "MPLS multicast label switched packet" },
  70     {ETHERTYPE_3C_NBP_DGRAM,    "3Com NBP Datagram"             },
  71     {ETHERTYPE_DEC,             "DEC proto"                     },
  72     {ETHERTYPE_DNA_DL,          "DEC DNA Dump/Load"             },
  73     {ETHERTYPE_DNA_RC,          "DEC DNA Remote Console"        },
  74     {ETHERTYPE_DNA_RT,          "DEC DNA Routing"               },
  75     {ETHERTYPE_LAT,             "DEC LAT"                       },
  76     {ETHERTYPE_DEC_DIAG,        "DEC Diagnostics"               },
  77     {ETHERTYPE_DEC_CUST,        "DEC Customer use"              },
  78     {ETHERTYPE_DEC_SCA,         "DEC LAVC/SCA"                  },
  79     {ETHERTYPE_ETHBRIDGE,       "Transparent Ethernet bridging" },
  80     {ETHERTYPE_CGMP,            "Cisco Group Management Protocol" },
  81     {ETHERTYPE_SLOW_PROTOCOLS,  "Slow Protocols"                },
  82     {ETHERTYPE_RTNET,           "RTNET Protocol"                },
  83
  84     /*
  85      * NDISWAN on Windows translates Ethernet frames from higher-level
  86      * protocols into PPP frames to hand to the PPP driver, and translates
  87      * PPP frames from the PPP driver to hand to the higher-level protocols.
  88      *
  89      * Apparently the PPP driver, on at least some versions of Windows,
  90      * passes frames for internal-to-PPP protocols up through NDISWAN;
  91      * the protocol type field appears to be passed through unchanged
  92      * (unlike what's done with, for example, the protocol type field
  93      * for IP, which is mapped from its PPP value to its Ethernet value).
  94      *
  95      * This means that we may see, on Ethernet captures, frames for
  96      * protocols internal to PPP, so we list as "Ethernet" protocol
  97      * types the PPP protocol types we've seen.
  98      */
  99     {PPP_IPCP,                  "PPP IP Control Protocol" },
 100     {PPP_LCP,                   "PPP Link Control Protocol" },
 101     {PPP_PAP,                   "PPP Password Authentication Protocol" },
 102     {PPP_CCP,                   "PPP Compression Control Protocol" },
 103     {0,                         NULL                            } };
 104
 105 static void add_dix_trailer(proto_tree *fh_tree, int trailer_id, tvbuff_t *tvb,
 106     tvbuff_t *next_tvb, int offset_after_etype, guint length_before);
 107
 108 void
 109 capture_ethertype(guint16 etype, const guchar *pd, int offset, int len,
 110                   packet_counts *ld)
 111 {
 112   switch (etype) {
 113     case ETHERTYPE_ARP:
 114       ld->arp++;
 115       break;
 116     case ETHERTYPE_IP:
 117       capture_ip(pd, offset, len, ld);
 118       break;
 119     case ETHERTYPE_IPv6:
 120       capture_ipv6(pd, offset, len, ld);
 121       break;
 122     case ETHERTYPE_IPX:
 123       capture_ipx(ld);
 124       break;
 125     case ETHERTYPE_VLAN:
 126       capture_vlan(pd, offset, len, ld);
 127       break;
 128     case ETHERTYPE_VINES_IP:
 129     case ETHERTYPE_VINES_ECHO:
 130       capture_vines(ld);
 131       break;
 132     default:
 133       ld->other++;
 134       break;
 135   }
 136 }
 137
 138 void
 139 ethertype(guint16 etype, tvbuff_t *tvb, int offset_after_etype,
 140                 packet_info *pinfo, proto_tree *tree, proto_tree *fh_tree,
 141                 int etype_id, int trailer_id)
 142 {
 143         char                    *description;
 144         tvbuff_t                *next_tvb;
 145         guint                   length_before;
 146         volatile gboolean       dissector_found;
 147         const char              *saved_proto, *exception_proto;
 148
 149         /* Add the Ethernet type to the protocol tree */
 150         if (tree) {
 151                 proto_tree_add_uint(fh_tree, etype_id, tvb,
 152                     offset_after_etype - 2, 2, etype);
 153         }
 154
 155         /* Tvbuff for the payload after the Ethernet type. */
 156         next_tvb = tvb_new_subset(tvb, offset_after_etype, -1, -1);
 157
 158         pinfo->ethertype = etype;
 159
 160         /* Remember how much data there is in it. */
 161         length_before = tvb_reported_length(next_tvb);
 162
 163         /* Look for sub-dissector, and call it if found.
 164            Catch BoundsError and ReportedBoundsError, so that if the
 165            reported length of "next_tvb" was reduced by some dissector
 166            before an exception was thrown, we can still put in an item
 167            for the trailer. */
 168         saved_proto = pinfo->current_proto;
 169         TRY {
 170                 dissector_found = dissector_try_port(ethertype_dissector_table,
 171                     etype, next_tvb, pinfo, tree);
 172         }
 173         CATCH2(BoundsError, ReportedBoundsError) {
 174                 /* Well, somebody threw an exception; that means that a
 175                    dissector was found, so we don't need to dissect
 176                    the payload as data or update the protocol or info
 177                    columns. */
 178                 dissector_found = TRUE;
 179
 180                 /* Save the protocol for which the exception was
 181                    thrown, and restore pinfo->current_proto to the
 182                    one for us, so if we throw an exception adding
 183                    the trailer (e.g., if we get an FCS when capturing,
 184                    but the snapshot length cut off the FCS), the
 185                    exception will reflect the appropriate protocol. */
 186                 exception_proto = pinfo->current_proto;
 187                 pinfo->current_proto = saved_proto;
 188
 189                 /* Add the trailer, if appropriate. */
 190                 add_dix_trailer(fh_tree, trailer_id, tvb, next_tvb,
 191                     offset_after_etype, length_before);
 192
 193                 /* Put back the protocol for which the exception is
 194                    thrown, and rethrow the exception, so the
 195                    appropriate indication for the exception can be
 196                    put into the tree. */
 197                 pinfo->current_proto = exception_proto;
 198                 RETHROW;
 199
 200                 /* XXX - RETHROW shouldn't return. */
 201                 g_assert_not_reached();
 202         }
 203         ENDTRY;
 204
 205         if (!dissector_found) {
 206                 /* No sub-dissector found.
 207                    Label rest of packet as "Data" */
 208                 call_dissector(data_handle,next_tvb, pinfo, tree);
 209
 210                 /* Label protocol */
 211                 switch (etype) {
 212
 213                 case ETHERTYPE_LOOP:
 214                         if (check_col(pinfo->cinfo, COL_PROTOCOL)) {
 215                                 col_add_fstr(pinfo->cinfo, COL_PROTOCOL, "LOOP");
 216                         }
 217                         break;
 218
 219                 default:
 220                         if (check_col(pinfo->cinfo, COL_PROTOCOL)) {
 221                                 col_add_fstr(pinfo->cinfo, COL_PROTOCOL, "0x%04x",
 222                                     etype);
 223                         }
 224                         break;
 225                 }
 226                 if (check_col(pinfo->cinfo, COL_INFO)) {
 227                         description = match_strval(etype, etype_vals);
 228                         if (description) {
 229                                 col_add_fstr(pinfo->cinfo, COL_INFO, "%s",
 230                                     description);
 231                         }
 232                 }
 233         }
 234
 235         add_dix_trailer(fh_tree, trailer_id, tvb, next_tvb, offset_after_etype,
 236             length_before);
 237 }
 238
 239 static void
 240 add_dix_trailer(proto_tree *fh_tree, int trailer_id, tvbuff_t *tvb,
 241     tvbuff_t *next_tvb, int offset_after_etype, guint length_before)
 242 {
 243         guint           length;
 244         tvbuff_t        *volatile trailer_tvb;
 245
 246         if (fh_tree == NULL)
 247                 return; /* we're not building a protocol tree */
 248
 249         if (trailer_id == -1)
 250                 return; /* our caller doesn't care about trailers */
 251
 252         /* OK, how much is there in that tvbuff now? */
 253         length = tvb_reported_length(next_tvb);
 254
 255         /* If there's less than there was before, what's left is
 256            a trailer. */
 257         if (length < length_before) {
 258                 /*
 259                  * Create a tvbuff for the padding.
 260                  */
 261                 TRY {
 262                         trailer_tvb = tvb_new_subset(tvb,
 263                             offset_after_etype + length, -1, -1);
 264                 }
 265                 CATCH2(BoundsError, ReportedBoundsError) {
 266                         /* The packet doesn't have "length" bytes worth of
 267                            captured data left in it.  No trailer to display. */
 268                         trailer_tvb = NULL;
 269                 }
 270                 ENDTRY;
 271         } else
 272                 trailer_tvb = NULL;     /* no trailer */
 273
 274         add_ethernet_trailer(fh_tree, trailer_id, tvb, trailer_tvb);
 275 }
 276
 277
 278 void
 279 proto_register_ethertype(void)
 280 {
 281         /* subdissector code */
 282         ethertype_dissector_table = register_dissector_table("ethertype",
 283             "Ethertype", FT_UINT16, BASE_HEX);
 284 }
 285
 286 void
 287 proto_reg_handoff_ethertype(void){
 288   data_handle = find_dissector("data");
 289 }