epan/dissectors/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 <epan/etypes.h>
  41 #include <epan/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_CISCOWL,         "Cisco Wireless"                },
  51     {ETHERTYPE_CENTRINO_PROMISC, "IEEE 802.11 (Centrino promiscuous)" },
  52     {ETHERTYPE_XNS_IDP,         "XNS Internet Datagram Protocol" },
  53     {ETHERTYPE_X25L3,           "X.25 Layer 3"                  },
  54     {ETHERTYPE_ARP,             "ARP"                           },
  55     {ETHERTYPE_REVARP,          "RARP"                          },
  56     {ETHERTYPE_DEC_LB,          "DEC LanBridge"                 },
  57     {ETHERTYPE_ATALK,           "Appletalk"                     },
  58     {ETHERTYPE_SNA,             "SNA-over-Ethernet"             },
  59     {ETHERTYPE_AARP,            "AARP"                          },
  60     {ETHERTYPE_IPX,             "Netware IPX/SPX"               },
  61     {ETHERTYPE_VINES_IP,        "Vines IP"                      },
  62     {ETHERTYPE_VINES_ECHO,      "Vines Echo"                    },
  63     {ETHERTYPE_TRAIN,           "Netmon Train"                  },
  64     {ETHERTYPE_LOOP,            "Loopback"                      }, /* Ethernet Loopback */
  65     {ETHERTYPE_WCP,             "Wellfleet Compression Protocol" },
  66     {ETHERTYPE_ISMP,            "Cabletron Interswitch Message Protocol" },
  67     {ETHERTYPE_ISMP_TBFLOOD,    "Cabletron SFVLAN 1.8 Tag-Based Flood" },
  68                                 /* for ISMP, see RFC 2641, RFC 2642, RFC 2643 */
  69     {ETHERTYPE_PPPOED,          "PPPoE Discovery"               },
  70     {ETHERTYPE_PPPOES,          "PPPoE Session"                 },
  71     {ETHERTYPE_INTEL_ANS,       "Intel ANS probe"               },
  72     {ETHERTYPE_MS_NLB_HEARTBEAT,        "MS NLB heartbeat"      },
  73     {ETHERTYPE_VLAN,            "802.1Q Virtual LAN"            },
  74     {ETHERTYPE_EAPOL,           "802.1X Authentication"         },
  75     {ETHERTYPE_RSN_PREAUTH,     "802.11i Pre-Authentication"    },
  76     {ETHERTYPE_MPLS,            "MPLS label switched packet"    },
  77     {ETHERTYPE_MPLS_MULTI,      "MPLS multicast label switched packet" },
  78     {ETHERTYPE_3C_NBP_DGRAM,    "3Com NBP Datagram"             },
  79     {ETHERTYPE_DEC,             "DEC proto"                     },
  80     {ETHERTYPE_DNA_DL,          "DEC DNA Dump/Load"             },
  81     {ETHERTYPE_DNA_RC,          "DEC DNA Remote Console"        },
  82     {ETHERTYPE_DNA_RT,          "DEC DNA Routing"               },
  83     {ETHERTYPE_LAT,             "DEC LAT"                       },
  84     {ETHERTYPE_DEC_DIAG,        "DEC Diagnostics"               },
  85     {ETHERTYPE_DEC_CUST,        "DEC Customer use"              },
  86     {ETHERTYPE_DEC_SCA,         "DEC LAVC/SCA"                  },
  87     {ETHERTYPE_DEC_LAST,        "DEC LAST"                      },
  88     {ETHERTYPE_ETHBRIDGE,       "Transparent Ethernet bridging" },
  89     {ETHERTYPE_CGMP,            "Cisco Group Management Protocol" },
  90     {ETHERTYPE_MAC_CONTROL,     "MAC Control"                   },
  91     {ETHERTYPE_SLOW_PROTOCOLS,  "Slow Protocols"                },
  92     {ETHERTYPE_RTMAC,           "Real-Time Media Access Control" },
  93     {ETHERTYPE_RTCFG,           "Real-Time Configuration Protocol" },
  94     {ETHERTYPE_CDMA2000_A10_UBS,"CDMA2000 A10 Unstructured byte stream" },
  95     {ETHERTYPE_PROFINET,        "PROFInet"                      },
  96     {ETHERTYPE_AOE,                     "ATA over Ethernet"             },
  97     {ETHERTYPE_CSM_ENCAPS,      "CSM_ENCAPS Protocol"             },
  98     {ETHERTYPE_IEEE802_OUI_EXTENDED, "IEEE 802a OUI Extended Ethertype" },
  99     {ETHERTYPE_LLDP,    "802.1 Link Layer Discovery Protocol (LLDP)" },
 100         {ETHERTYPE_3GPP2,       "3GPP2 protocol" },
 101     /*
 102      * NDISWAN on Windows translates Ethernet frames from higher-level
 103      * protocols into PPP frames to hand to the PPP driver, and translates
 104      * PPP frames from the PPP driver to hand to the higher-level protocols.
 105      *
 106      * Apparently the PPP driver, on at least some versions of Windows,
 107      * passes frames for internal-to-PPP protocols up through NDISWAN;
 108      * the protocol type field appears to be passed through unchanged
 109      * (unlike what's done with, for example, the protocol type field
 110      * for IP, which is mapped from its PPP value to its Ethernet value).
 111      *
 112      * This means that we may see, on Ethernet captures, frames for
 113      * protocols internal to PPP, so we list as "Ethernet" protocol
 114      * types the PPP protocol types we've seen.
 115      */
 116     {PPP_IPCP,                  "PPP IP Control Protocol" },
 117     {PPP_LCP,                   "PPP Link Control Protocol" },
 118     {PPP_PAP,                   "PPP Password Authentication Protocol" },
 119     {PPP_CCP,                   "PPP Compression Control Protocol" },
 120     {0,                         NULL                            } };
 121
 122 static void add_dix_trailer(proto_tree *fh_tree, int trailer_id, tvbuff_t *tvb,
 123     tvbuff_t *next_tvb, int offset_after_etype, guint length_before,
 124     gint fcs_len);
 125
 126 void
 127 capture_ethertype(guint16 etype, const guchar *pd, int offset, int len,
 128                   packet_counts *ld)
 129 {
 130   switch (etype) {
 131     case ETHERTYPE_ARP:
 132       ld->arp++;
 133       break;
 134     case ETHERTYPE_IP:
 135       capture_ip(pd, offset, len, ld);
 136       break;
 137     case ETHERTYPE_IPv6:
 138       capture_ipv6(pd, offset, len, ld);
 139       break;
 140     case ETHERTYPE_IPX:
 141       capture_ipx(ld);
 142       break;
 143     case ETHERTYPE_VLAN:
 144       capture_vlan(pd, offset, len, ld);
 145       break;
 146     case ETHERTYPE_VINES_IP:
 147     case ETHERTYPE_VINES_ECHO:
 148       capture_vines(ld);
 149       break;
 150     default:
 151       ld->other++;
 152       break;
 153   }
 154 }
 155
 156 void
 157 ethertype(guint16 etype, tvbuff_t *tvb, int offset_after_etype,
 158                 packet_info *pinfo, proto_tree *tree, proto_tree *fh_tree,
 159                 int etype_id, int trailer_id, int fcs_len)
 160 {
 161         const char              *description;
 162         tvbuff_t                *next_tvb;
 163         guint                   length_before;
 164         volatile gboolean       dissector_found = FALSE;
 165         const char              *saved_proto;
 166
 167         /* Add the Ethernet type to the protocol tree */
 168         if (tree) {
 169                 proto_tree_add_uint(fh_tree, etype_id, tvb,
 170                     offset_after_etype - 2, 2, etype);
 171         }
 172
 173         /* Tvbuff for the payload after the Ethernet type. */
 174         next_tvb = tvb_new_subset(tvb, offset_after_etype, -1, -1);
 175
 176         pinfo->ethertype = etype;
 177
 178         /* Remember how much data there is in it. */
 179         length_before = tvb_reported_length(next_tvb);
 180
 181         /* Look for sub-dissector, and call it if found.
 182            Catch exceptions, so that if the reported length of "next_tvb"
 183            was reduced by some dissector before an exception was thrown,
 184            we can still put in an item for the trailer. */
 185         saved_proto = pinfo->current_proto;
 186         TRY {
 187                 dissector_found = dissector_try_port(ethertype_dissector_table,
 188                     etype, next_tvb, pinfo, tree);
 189         }
 190         CATCH(BoundsError) {
 191                 /* Somebody threw BoundsError, which means that:
 192
 193                      1) a dissector was found, so we don't need to
 194                         dissect the payload as data or update the
 195                         protocol or info columns;
 196
 197                      2) dissecting the payload found that the packet was
 198                         cut off by a snapshot length before the end of
 199                         the payload.  The trailer comes after the payload,
 200                         so *all* of the trailer is cut off, and we'll
 201                         just get another BoundsError if we add the trailer.
 202
 203                    Therefore, we just rethrow the exception so it gets
 204                    reported; we don't dissect the trailer or do anything
 205                    else. */
 206                  RETHROW;
 207         }
 208         CATCH_ALL {
 209                 /* Somebody threw an exception other than BoundsError, which
 210                    means that a dissector was found, so we don't need to
 211                    dissect the payload as data or update the protocol or info
 212                    columns.  We just show the exception and then drive on
 213                    to show the trailer, after noting that a dissector was
 214                    found and restoring the protocol value that was in effect
 215                    before we called the subdissector. */
 216                 show_exception(next_tvb, pinfo, tree, EXCEPT_CODE, GET_MESSAGE);
 217                 dissector_found = TRUE;
 218                 pinfo->current_proto = saved_proto;
 219         }
 220         ENDTRY;
 221
 222         if (!dissector_found) {
 223                 /* No sub-dissector found.
 224                    Label rest of packet as "Data" */
 225                 call_dissector(data_handle,next_tvb, pinfo, tree);
 226
 227                 /* Label protocol */
 228                 if (check_col(pinfo->cinfo, COL_PROTOCOL)) {
 229                         col_add_fstr(pinfo->cinfo, COL_PROTOCOL, "0x%04x",
 230                             etype);
 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 }