packet-ethertype.c

   1 /* ethertype.c
   2  * Routines for calling the right protocol for the ethertype.
   3  *
   4  * $Id: packet-ethertype.c,v 1.45 2004/02/21 05:12:44 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-frame.h"
  35 #include "packet-ip.h"
  36 #include "packet-ipv6.h"
  37 #include "packet-ipx.h"
  38 #include "packet-vlan.h"
  39 #include "packet-vines.h"
  40 #include "etypes.h"
  41 #include "ppptypes.h"
  42
  43 static dissector_table_t ethertype_dissector_table;
  44
  45 static dissector_handle_t data_handle;
  46
  47 const value_string etype_vals[] = {
  48     {ETHERTYPE_IP,              "IP"                            },
  49     {ETHERTYPE_IPv6,            "IPv6"                          },
  50     {ETHERTYPE_X25L3,           "X.25 Layer 3"                  },
  51     {ETHERTYPE_ARP,             "ARP"                           },
  52     {ETHERTYPE_REVARP,          "RARP"                          },
  53     {ETHERTYPE_DEC_LB,          "DEC LanBridge"                 },
  54     {ETHERTYPE_ATALK,           "Appletalk"                     },
  55     {ETHERTYPE_SNA,             "SNA-over-Ethernet"             },
  56     {ETHERTYPE_AARP,            "AARP"                          },
  57     {ETHERTYPE_IPX,             "Netware IPX/SPX"               },
  58     {ETHERTYPE_VINES_IP,        "Vines IP"                      },
  59     {ETHERTYPE_VINES_ECHO,      "Vines Echo"                    },
  60     {ETHERTYPE_TRAIN,           "Netmon Train"                  },
  61     {ETHERTYPE_LOOP,            "Loopback"                      }, /* Ethernet Loopback */
  62     {ETHERTYPE_WCP,             "Wellfleet Compression Protocol" },
  63     {ETHERTYPE_ISMP,            "Cabletron Interswitch Message Protocol" },
  64     {ETHERTYPE_ISMP_TBFLOOD,    "Cabletron SFVLAN 1.8 Tag-Based Flood" },
  65                                 /* for ISMP, see RFC 2641, RFC 2642, RFC 2643 */
  66     {ETHERTYPE_PPPOED,          "PPPoE Discovery"               },
  67     {ETHERTYPE_PPPOES,          "PPPoE Session"                 },
  68     {ETHERTYPE_INTEL_ANS,       "Intel ANS probe"               },
  69     {ETHERTYPE_MS_NLB_HEARTBEAT,        "MS NLB heartbeat"      },
  70     {ETHERTYPE_VLAN,            "802.1Q Virtual LAN"            },
  71     {ETHERTYPE_EAPOL,           "802.1X Authentication"         },
  72     {ETHERTYPE_MPLS,            "MPLS label switched packet"    },
  73     {ETHERTYPE_MPLS_MULTI,      "MPLS multicast label switched packet" },
  74     {ETHERTYPE_3C_NBP_DGRAM,    "3Com NBP Datagram"             },
  75     {ETHERTYPE_DEC,             "DEC proto"                     },
  76     {ETHERTYPE_DNA_DL,          "DEC DNA Dump/Load"             },
  77     {ETHERTYPE_DNA_RC,          "DEC DNA Remote Console"        },
  78     {ETHERTYPE_DNA_RT,          "DEC DNA Routing"               },
  79     {ETHERTYPE_LAT,             "DEC LAT"                       },
  80     {ETHERTYPE_DEC_DIAG,        "DEC Diagnostics"               },
  81     {ETHERTYPE_DEC_CUST,        "DEC Customer use"              },
  82     {ETHERTYPE_DEC_SCA,         "DEC LAVC/SCA"                  },
  83     {ETHERTYPE_ETHBRIDGE,       "Transparent Ethernet bridging" },
  84     {ETHERTYPE_CGMP,            "Cisco Group Management Protocol" },
  85     {ETHERTYPE_SLOW_PROTOCOLS,  "Slow Protocols"                },
  86     {ETHERTYPE_RTNET,           "RTNET Protocol"                },
  87     {ETHERTYPE_RTCFG,           "RTCFG Protocol"                },
  88     {ETHERTYPE_PROFINET,        "PROFInet"                },
  89
  90     /*
  91      * NDISWAN on Windows translates Ethernet frames from higher-level
  92      * protocols into PPP frames to hand to the PPP driver, and translates
  93      * PPP frames from the PPP driver to hand to the higher-level protocols.
  94      *
  95      * Apparently the PPP driver, on at least some versions of Windows,
  96      * passes frames for internal-to-PPP protocols up through NDISWAN;
  97      * the protocol type field appears to be passed through unchanged
  98      * (unlike what's done with, for example, the protocol type field
  99      * for IP, which is mapped from its PPP value to its Ethernet value).
 100      *
 101      * This means that we may see, on Ethernet captures, frames for
 102      * protocols internal to PPP, so we list as "Ethernet" protocol
 103      * types the PPP protocol types we've seen.
 104      */
 105     {PPP_IPCP,                  "PPP IP Control Protocol" },
 106     {PPP_LCP,                   "PPP Link Control Protocol" },
 107     {PPP_PAP,                   "PPP Password Authentication Protocol" },
 108     {PPP_CCP,                   "PPP Compression Control Protocol" },
 109     {0,                         NULL                            } };
 110
 111 static void add_dix_trailer(proto_tree *fh_tree, int trailer_id, tvbuff_t *tvb,
 112     tvbuff_t *next_tvb, int offset_after_etype, guint length_before,
 113     gint fcs_len);
 114
 115 void
 116 capture_ethertype(guint16 etype, const guchar *pd, int offset, int len,
 117                   packet_counts *ld)
 118 {
 119   switch (etype) {
 120     case ETHERTYPE_ARP:
 121       ld->arp++;
 122       break;
 123     case ETHERTYPE_IP:
 124       capture_ip(pd, offset, len, ld);
 125       break;
 126     case ETHERTYPE_IPv6:
 127       capture_ipv6(pd, offset, len, ld);
 128       break;
 129     case ETHERTYPE_IPX:
 130       capture_ipx(ld);
 131       break;
 132     case ETHERTYPE_VLAN:
 133       capture_vlan(pd, offset, len, ld);
 134       break;
 135     case ETHERTYPE_VINES_IP:
 136     case ETHERTYPE_VINES_ECHO:
 137       capture_vines(ld);
 138       break;
 139     default:
 140       ld->other++;
 141       break;
 142   }
 143 }
 144
 145 void
 146 ethertype(guint16 etype, tvbuff_t *tvb, int offset_after_etype,
 147                 packet_info *pinfo, proto_tree *tree, proto_tree *fh_tree,
 148                 int etype_id, int trailer_id, int fcs_len)
 149 {
 150         char                    *description;
 151         tvbuff_t                *next_tvb;
 152         guint                   length_before;
 153         volatile gboolean       dissector_found;
 154         const char              *saved_proto;
 155
 156         /* Add the Ethernet type to the protocol tree */
 157         if (tree) {
 158                 proto_tree_add_uint(fh_tree, etype_id, tvb,
 159                     offset_after_etype - 2, 2, etype);
 160         }
 161
 162         /* Tvbuff for the payload after the Ethernet type. */
 163         next_tvb = tvb_new_subset(tvb, offset_after_etype, -1, -1);
 164
 165         pinfo->ethertype = etype;
 166
 167         /* Remember how much data there is in it. */
 168         length_before = tvb_reported_length(next_tvb);
 169
 170         /* Look for sub-dissector, and call it if found.
 171            Catch exceptions, so that if the reported length of "next_tvb"
 172            was reduced by some dissector before an exception was thrown,
 173            we can still put in an item for the trailer. */
 174         saved_proto = pinfo->current_proto;
 175         TRY {
 176                 dissector_found = dissector_try_port(ethertype_dissector_table,
 177                     etype, next_tvb, pinfo, tree);
 178         }
 179         CATCH(BoundsError) {
 180                 /* Somebody threw BoundsError, which means that:
 181
 182                      1) a dissector was found, so we don't need to
 183                         dissect the payload as data or update the
 184                         protocol or info columns;
 185
 186                      2) dissecting the payload found that the packet was
 187                         cut off by a snapshot length before the end of
 188                         the payload.  The trailer comes after the payload,
 189                         so *all* of the trailer is cut off, and we'll
 190                         just get another BoundsError if we add the trailer.
 191
 192                    Therefore, we just rethrow the exception so it gets
 193                    reported; we don't dissect the trailer or do anything
 194                    else. */
 195                  RETHROW;
 196         }
 197         CATCH_ALL {
 198                 /* Somebody threw an exception other than BoundsError, which
 199                    means that a dissector was found, so we don't need to
 200                    dissect the payload as data or update the protocol or info
 201                    columns.  We just show the exception and then drive on
 202                    to show the trailer, after noting that a dissector was
 203                    found and restoring the protocol value that was in effect
 204                    before we called the subdissector. */
 205                 show_exception(next_tvb, pinfo, tree, EXCEPT_CODE);
 206                 dissector_found = TRUE;
 207                 pinfo->current_proto = saved_proto;
 208         }
 209         ENDTRY;
 210
 211         if (!dissector_found) {
 212                 /* No sub-dissector found.
 213                    Label rest of packet as "Data" */
 214                 call_dissector(data_handle,next_tvb, pinfo, tree);
 215
 216                 /* Label protocol */
 217                 switch (etype) {
 218
 219                 case ETHERTYPE_LOOP:
 220                         if (check_col(pinfo->cinfo, COL_PROTOCOL)) {
 221                                 col_add_fstr(pinfo->cinfo, COL_PROTOCOL, "LOOP");
 222                         }
 223                         break;
 224
 225                 default:
 226                         if (check_col(pinfo->cinfo, COL_PROTOCOL)) {
 227                                 col_add_fstr(pinfo->cinfo, COL_PROTOCOL, "0x%04x",
 228                                     etype);
 229                         }
 230                         break;
 231                 }
 232                 if (check_col(pinfo->cinfo, COL_INFO)) {
 233                         description = match_strval(etype, etype_vals);
 234                         if (description) {
 235                                 col_add_fstr(pinfo->cinfo, COL_INFO, "%s",
 236                                     description);
 237                         }
 238                 }
 239         }
 240
 241         add_dix_trailer(fh_tree, trailer_id, tvb, next_tvb, offset_after_etype,
 242             length_before, fcs_len);
 243 }
 244
 245 static void
 246 add_dix_trailer(proto_tree *fh_tree, int trailer_id, tvbuff_t *tvb,
 247     tvbuff_t *next_tvb, int offset_after_etype, guint length_before,
 248     gint fcs_len)
 249 {
 250         guint           length;
 251         tvbuff_t        *volatile trailer_tvb;
 252
 253         if (fh_tree == NULL)
 254                 return; /* we're not building a protocol tree */
 255
 256         if (trailer_id == -1)
 257                 return; /* our caller doesn't care about trailers */
 258
 259         /* OK, how much is there in that tvbuff now? */
 260         length = tvb_reported_length(next_tvb);
 261
 262         /* If there's less than there was before, what's left is
 263            a trailer. */
 264         if (length < length_before) {
 265                 /*
 266                  * Is any of the padding present in the tvbuff?
 267                  */
 268                 if (tvb_offset_exists(tvb, offset_after_etype + length)) {
 269                         /*
 270                          * Yes - create a tvbuff for the padding.
 271                          */
 272                         trailer_tvb = tvb_new_subset(tvb,
 273                             offset_after_etype + length, -1, -1);
 274                 } else {
 275                         /*
 276                          * No - don't bother showing the trailer.
 277                          * XXX - show a Short Frame indication?
 278                          */
 279                         trailer_tvb = NULL;
 280                 }
 281         } else
 282                 trailer_tvb = NULL;     /* no trailer */
 283
 284         add_ethernet_trailer(fh_tree, trailer_id, tvb, trailer_tvb, fcs_len);
 285 }
 286
 287 void
 288 proto_register_ethertype(void)
 289 {
 290         /* subdissector code */
 291         ethertype_dissector_table = register_dissector_table("ethertype",
 292             "Ethertype", FT_UINT16, BASE_HEX);
 293 }
 294
 295 void
 296 proto_reg_handoff_ethertype(void)
 297 {
 298         data_handle = find_dissector("data");
 299 }