packet-ethertype.c

   1 /* ethertype.c
   2  * Routines for calling the right protocol for the ethertype.
   3  *
   4  * $Id$
   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_RSN_PREAUTH,     "802.11i Pre-Authentication"    },
  73     {ETHERTYPE_MPLS,            "MPLS label switched packet"    },
  74     {ETHERTYPE_MPLS_MULTI,      "MPLS multicast label switched packet" },
  75     {ETHERTYPE_3C_NBP_DGRAM,    "3Com NBP Datagram"             },
  76     {ETHERTYPE_DEC,             "DEC proto"                     },
  77     {ETHERTYPE_DNA_DL,          "DEC DNA Dump/Load"             },
  78     {ETHERTYPE_DNA_RC,          "DEC DNA Remote Console"        },
  79     {ETHERTYPE_DNA_RT,          "DEC DNA Routing"               },
  80     {ETHERTYPE_LAT,             "DEC LAT"                       },
  81     {ETHERTYPE_DEC_DIAG,        "DEC Diagnostics"               },
  82     {ETHERTYPE_DEC_CUST,        "DEC Customer use"              },
  83     {ETHERTYPE_DEC_SCA,         "DEC LAVC/SCA"                  },
  84     {ETHERTYPE_ETHBRIDGE,       "Transparent Ethernet bridging" },
  85     {ETHERTYPE_CGMP,            "Cisco Group Management Protocol" },
  86     {ETHERTYPE_SLOW_PROTOCOLS,  "Slow Protocols"                },
  87     {ETHERTYPE_RTNET,           "RTNET Protocol"                },
  88     {ETHERTYPE_RTCFG,           "RTCFG Protocol"                },
  89     {ETHERTYPE_PROFINET,        "PROFInet"                },
  90
  91     /*
  92      * NDISWAN on Windows translates Ethernet frames from higher-level
  93      * protocols into PPP frames to hand to the PPP driver, and translates
  94      * PPP frames from the PPP driver to hand to the higher-level protocols.
  95      *
  96      * Apparently the PPP driver, on at least some versions of Windows,
  97      * passes frames for internal-to-PPP protocols up through NDISWAN;
  98      * the protocol type field appears to be passed through unchanged
  99      * (unlike what's done with, for example, the protocol type field
 100      * for IP, which is mapped from its PPP value to its Ethernet value).
 101      *
 102      * This means that we may see, on Ethernet captures, frames for
 103      * protocols internal to PPP, so we list as "Ethernet" protocol
 104      * types the PPP protocol types we've seen.
 105      */
 106     {PPP_IPCP,                  "PPP IP Control Protocol" },
 107     {PPP_LCP,                   "PPP Link Control Protocol" },
 108     {PPP_PAP,                   "PPP Password Authentication Protocol" },
 109     {PPP_CCP,                   "PPP Compression Control Protocol" },
 110     {0,                         NULL                            } };
 111
 112 static void add_dix_trailer(proto_tree *fh_tree, int trailer_id, tvbuff_t *tvb,
 113     tvbuff_t *next_tvb, int offset_after_etype, guint length_before,
 114     gint fcs_len);
 115
 116 void
 117 capture_ethertype(guint16 etype, const guchar *pd, int offset, int len,
 118                   packet_counts *ld)
 119 {
 120   switch (etype) {
 121     case ETHERTYPE_ARP:
 122       ld->arp++;
 123       break;
 124     case ETHERTYPE_IP:
 125       capture_ip(pd, offset, len, ld);
 126       break;
 127     case ETHERTYPE_IPv6:
 128       capture_ipv6(pd, offset, len, ld);
 129       break;
 130     case ETHERTYPE_IPX:
 131       capture_ipx(ld);
 132       break;
 133     case ETHERTYPE_VLAN:
 134       capture_vlan(pd, offset, len, ld);
 135       break;
 136     case ETHERTYPE_VINES_IP:
 137     case ETHERTYPE_VINES_ECHO:
 138       capture_vines(ld);
 139       break;
 140     default:
 141       ld->other++;
 142       break;
 143   }
 144 }
 145
 146 void
 147 ethertype(guint16 etype, tvbuff_t *tvb, int offset_after_etype,
 148                 packet_info *pinfo, proto_tree *tree, proto_tree *fh_tree,
 149                 int etype_id, int trailer_id, int fcs_len)
 150 {
 151         char                    *description;
 152         tvbuff_t                *next_tvb;
 153         guint                   length_before;
 154         volatile gboolean       dissector_found;
 155         const char              *saved_proto;
 156
 157         /* Add the Ethernet type to the protocol tree */
 158         if (tree) {
 159                 proto_tree_add_uint(fh_tree, etype_id, tvb,
 160                     offset_after_etype - 2, 2, etype);
 161         }
 162
 163         /* Tvbuff for the payload after the Ethernet type. */
 164         next_tvb = tvb_new_subset(tvb, offset_after_etype, -1, -1);
 165
 166         pinfo->ethertype = etype;
 167
 168         /* Remember how much data there is in it. */
 169         length_before = tvb_reported_length(next_tvb);
 170
 171         /* Look for sub-dissector, and call it if found.
 172            Catch exceptions, so that if the reported length of "next_tvb"
 173            was reduced by some dissector before an exception was thrown,
 174            we can still put in an item for the trailer. */
 175         saved_proto = pinfo->current_proto;
 176         TRY {
 177                 dissector_found = dissector_try_port(ethertype_dissector_table,
 178                     etype, next_tvb, pinfo, tree);
 179         }
 180         CATCH(BoundsError) {
 181                 /* Somebody threw BoundsError, which means that:
 182
 183                      1) a dissector was found, so we don't need to
 184                         dissect the payload as data or update the
 185                         protocol or info columns;
 186
 187                      2) dissecting the payload found that the packet was
 188                         cut off by a snapshot length before the end of
 189                         the payload.  The trailer comes after the payload,
 190                         so *all* of the trailer is cut off, and we'll
 191                         just get another BoundsError if we add the trailer.
 192
 193                    Therefore, we just rethrow the exception so it gets
 194                    reported; we don't dissect the trailer or do anything
 195                    else. */
 196                  RETHROW;
 197         }
 198         CATCH_ALL {
 199                 /* Somebody threw an exception other than BoundsError, which
 200                    means that a dissector was found, so we don't need to
 201                    dissect the payload as data or update the protocol or info
 202                    columns.  We just show the exception and then drive on
 203                    to show the trailer, after noting that a dissector was
 204                    found and restoring the protocol value that was in effect
 205                    before we called the subdissector. */
 206                 show_exception(next_tvb, pinfo, tree, EXCEPT_CODE);
 207                 dissector_found = TRUE;
 208                 pinfo->current_proto = saved_proto;
 209         }
 210         ENDTRY;
 211
 212         if (!dissector_found) {
 213                 /* No sub-dissector found.
 214                    Label rest of packet as "Data" */
 215                 call_dissector(data_handle,next_tvb, pinfo, tree);
 216
 217                 /* Label protocol */
 218                 switch (etype) {
 219
 220                 case ETHERTYPE_LOOP:
 221                         if (check_col(pinfo->cinfo, COL_PROTOCOL)) {
 222                                 col_add_fstr(pinfo->cinfo, COL_PROTOCOL, "LOOP");
 223                         }
 224                         break;
 225
 226                 default:
 227                         if (check_col(pinfo->cinfo, COL_PROTOCOL)) {
 228                                 col_add_fstr(pinfo->cinfo, COL_PROTOCOL, "0x%04x",
 229                                     etype);
 230                         }
 231                         break;
 232                 }
 233                 if (check_col(pinfo->cinfo, COL_INFO)) {
 234                         description = match_strval(etype, etype_vals);
 235                         if (description) {
 236                                 col_add_fstr(pinfo->cinfo, COL_INFO, "%s",
 237                                     description);
 238                         }
 239                 }
 240         }
 241
 242         add_dix_trailer(fh_tree, trailer_id, tvb, next_tvb, offset_after_etype,
 243             length_before, fcs_len);
 244 }
 245
 246 static void
 247 add_dix_trailer(proto_tree *fh_tree, int trailer_id, tvbuff_t *tvb,
 248     tvbuff_t *next_tvb, int offset_after_etype, guint length_before,
 249     gint fcs_len)
 250 {
 251         guint           length;
 252         tvbuff_t        *volatile trailer_tvb;
 253
 254         if (fh_tree == NULL)
 255                 return; /* we're not building a protocol tree */
 256
 257         if (trailer_id == -1)
 258                 return; /* our caller doesn't care about trailers */
 259
 260         /* OK, how much is there in that tvbuff now? */
 261         length = tvb_reported_length(next_tvb);
 262
 263         /* If there's less than there was before, what's left is
 264            a trailer. */
 265         if (length < length_before) {
 266                 /*
 267                  * Is any of the padding present in the tvbuff?
 268                  */
 269                 if (tvb_offset_exists(tvb, offset_after_etype + length)) {
 270                         /*
 271                          * Yes - create a tvbuff for the padding.
 272                          */
 273                         trailer_tvb = tvb_new_subset(tvb,
 274                             offset_after_etype + length, -1, -1);
 275                 } else {
 276                         /*
 277                          * No - don't bother showing the trailer.
 278                          * XXX - show a Short Frame indication?
 279                          */
 280                         trailer_tvb = NULL;
 281                 }
 282         } else
 283                 trailer_tvb = NULL;     /* no trailer */
 284
 285         add_ethernet_trailer(fh_tree, trailer_id, tvb, trailer_tvb, fcs_len);
 286 }
 287
 288 void
 289 proto_register_ethertype(void)
 290 {
 291         /* subdissector code */
 292         ethertype_dissector_table = register_dissector_table("ethertype",
 293             "Ethertype", FT_UINT16, BASE_HEX);
 294 }
 295
 296 void
 297 proto_reg_handoff_ethertype(void)
 298 {
 299         data_handle = find_dissector("data");
 300 }