packet-eapol.c

   1 /* packet-eapol.c
   2  * Routines for EAPOL 802.1X authentication header disassembly
   3  *
   4  * $Id: packet-eapol.c,v 1.6 2002/02/17 00:51:19 guy Exp $
   5  *
   6  * Ethereal - Network traffic analyzer
   7  * By Gerald Combs <gerald@ethereal.com>
   8  * Copyright 1998 Gerald Combs
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License
  12  * as published by the Free Software Foundation; either version 2
  13  * of the License, or (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  23  */
  24
  25 #ifdef HAVE_CONFIG_H
  26 # include "config.h"
  27 #endif
  28
  29 #ifdef HAVE_SYS_TYPES_H
  30 # include <sys/types.h>
  31 #endif
  32
  33 #ifdef HAVE_NETINET_IN_H
  34 # include <netinet/in.h>
  35 #endif
  36
  37 #include <glib.h>
  38 #include <epan/packet.h>
  39 #include "packet-ieee8023.h"
  40 #include "packet-ipx.h"
  41 #include "packet-llc.h"
  42 #include "etypes.h"
  43
  44 static int proto_eapol = -1;
  45 static int hf_eapol_version = -1;
  46 static int hf_eapol_type = -1;
  47 static int hf_eapol_len = -1;
  48
  49 static gint ett_eapol = -1;
  50
  51 static dissector_handle_t data_handle;
  52
  53 typedef struct _e_eapol
  54 {
  55     guint8 eapol_ver;
  56     guint8 eapol_type;
  57     guint16 eapol_len;
  58 } e_eapol;
  59
  60 static const char *eapol_type_name[] = {
  61     "EAP",
  62     "Start",
  63     "Logoff",
  64     "Key",
  65     "Encapsulated ASF Alert"
  66 };
  67 #define EAPOL_TYPE_COUNT (sizeof(eapol_type_name)/sizeof(eapol_type_name[0]))
  68
  69 extern void dissect_eap(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree);
  70
  71 static void
  72 dissect_eapol(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
  73 {
  74   e_eapol     eapolh;
  75   guint       len;
  76   proto_tree *ti;
  77   proto_tree *volatile eapol_tree;
  78   tvbuff_t   *next_tvb;
  79
  80   if (check_col(pinfo->cinfo, COL_PROTOCOL))
  81     col_set_str(pinfo->cinfo, COL_PROTOCOL, "EAPOL");
  82   if (check_col(pinfo->cinfo, COL_INFO))
  83     col_clear(pinfo->cinfo, COL_INFO);
  84
  85   tvb_memcpy(tvb, (guint8 *)&eapolh, 0, sizeof(eapolh));
  86   eapolh.eapol_len = ntohs(eapolh.eapol_len);
  87
  88   len = sizeof(eapolh) + eapolh.eapol_len;
  89
  90   set_actual_length(tvb, len);
  91
  92   eapol_tree = NULL;
  93
  94   if (tree) {
  95     ti = proto_tree_add_item(tree, proto_eapol, tvb, 0, len, FALSE);
  96     eapol_tree = proto_item_add_subtree(ti, ett_eapol);
  97
  98     proto_tree_add_uint(eapol_tree, hf_eapol_version, tvb, 0, 1, eapolh.eapol_ver);
  99     proto_tree_add_text(eapol_tree, tvb, 1, 1, "Type: %s (%u)",
 100                         eapolh.eapol_type > EAPOL_TYPE_COUNT?
 101                         "Unknown" : eapol_type_name[eapolh.eapol_type],
 102                         eapolh.eapol_type);
 103     proto_tree_add_uint(eapol_tree, hf_eapol_len,    tvb, 2, 2, eapolh.eapol_len);
 104   }
 105
 106   next_tvb = tvb_new_subset(tvb, 4, -1, -1);
 107
 108   if (eapolh.eapol_type == 0 && next_tvb != NULL)
 109       dissect_eap(next_tvb, pinfo, eapol_tree);
 110   else
 111       call_dissector(data_handle,tvb_new_subset(tvb, 4,-1,tvb_reported_length_remaining(tvb,4)), pinfo, tree);
 112 }
 113
 114 void
 115 proto_register_eapol(void)
 116 {
 117   static hf_register_info hf[] = {
 118         { &hf_eapol_version, {
 119                 "Version", "eapol.version", FT_UINT8, BASE_DEC,
 120                 NULL, 0x0, "", HFILL }},
 121         { &hf_eapol_type, {
 122                 "Type", "eapol.type", FT_UINT8, BASE_DEC,
 123                 0, 0x0, "", HFILL }},
 124         { &hf_eapol_len, {
 125                 "Length", "eapol.len", FT_UINT16, BASE_DEC,
 126                 NULL, 0x0, "Length", HFILL }},
 127   };
 128   static gint *ett[] = {
 129         &ett_eapol,
 130   };
 131
 132   proto_eapol = proto_register_protocol("802.1x Authentication", "EAPOL", "eapol");
 133   proto_register_field_array(proto_eapol, hf, array_length(hf));
 134   proto_register_subtree_array(ett, array_length(ett));
 135 }
 136
 137 void
 138 proto_reg_handoff_eapol(void)
 139 {
 140   dissector_handle_t eapol_handle;
 141
 142   data_handle = find_dissector("data");
 143   eapol_handle = create_dissector_handle(dissect_eapol, proto_eapol);
 144   dissector_add("ethertype", ETHERTYPE_EAPOL, eapol_handle);
 145 }