epan/dissectors/packet-ieee802a.c

   1 /* packet-ieee802a.c
   2  * Routines for IEEE 802a
   3  *
   4  * $Id$
   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 #include <glib.h>
  30 #include <epan/packet.h>
  31 #include <epan/oui.h>
  32 #include <epan/etypes.h>
  33
  34 #include "packet-ieee802a.h"
  35
  36 static int proto_ieee802a = -1;
  37 static int hf_ieee802a_oui = -1;
  38 static int hf_ieee802a_pid = -1;
  39
  40 static gint ett_ieee802a = -1;
  41
  42 static dissector_handle_t data_handle;
  43
  44 /*
  45  * Hash table for translating OUIs to a dissector table/field info pair;
  46  * the dissector table maps PID values to dissectors, and the field
  47  * corresponds to the PID for that OUI.
  48  */
  49 typedef struct {
  50         dissector_table_t table;
  51         hf_register_info *field_info;
  52 } oui_info_t;
  53
  54 static GHashTable *oui_info_table = NULL;
  55
  56 /*
  57  * Add an entry for a new OUI.
  58  */
  59 void
  60 ieee802a_add_oui(guint32 oui, const char *table_name, char *table_ui_name,
  61     hf_register_info *hf_item)
  62 {
  63         oui_info_t *new_info;
  64
  65         new_info = g_malloc(sizeof (oui_info_t));
  66         new_info->table = register_dissector_table(table_name,
  67             table_ui_name, FT_UINT16, BASE_HEX);
  68         new_info->field_info = hf_item;
  69
  70         /*
  71          * Create the hash table for OUI information, if it doesn't
  72          * already exist.
  73          */
  74         if (oui_info_table == NULL) {
  75                 oui_info_table = g_hash_table_new(g_direct_hash,
  76                     g_direct_equal);
  77         }
  78         g_hash_table_insert(oui_info_table, GUINT_TO_POINTER(oui), new_info);
  79 }
  80
  81 static void
  82 dissect_ieee802a(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
  83 {
  84         proto_tree      *ieee802a_tree = NULL;
  85         proto_item      *ti;
  86         int             offset = 0;
  87         tvbuff_t        *next_tvb;
  88         guint32         oui;
  89         guint16         etype;
  90         oui_info_t      *oui_info;
  91         dissector_table_t subdissector_table;
  92         int             hf;
  93
  94         if (check_col(pinfo->cinfo, COL_PROTOCOL)) {
  95                 col_set_str(pinfo->cinfo, COL_PROTOCOL, "IEEE802a");
  96         }
  97         if (check_col(pinfo->cinfo, COL_INFO)) {
  98                 col_clear(pinfo->cinfo, COL_INFO);
  99         }
 100
 101         if (tree) {
 102                 ti = proto_tree_add_item(tree, proto_ieee802a, tvb, 0, -1, FALSE);
 103                 ieee802a_tree = proto_item_add_subtree(ti, ett_ieee802a);
 104         } else
 105                 ieee802a_tree = NULL;
 106
 107         oui =   tvb_get_ntoh24(tvb, offset);
 108         etype = tvb_get_ntohs(tvb, offset+3);
 109
 110         if (check_col(pinfo->cinfo, COL_INFO)) {
 111                 col_add_fstr(pinfo->cinfo, COL_INFO,
 112                     "OUI 0x%06X (%s), PID 0x%04X",
 113                     oui, val_to_str(oui, oui_vals, "Unknown"), etype);
 114         }
 115         if (tree) {
 116                 proto_tree_add_uint(ieee802a_tree, hf_ieee802a_oui,
 117                     tvb, offset, 3, oui);
 118         }
 119
 120         /*
 121          * Do we have information for this OUI?
 122          */
 123         if (oui_info_table != NULL &&
 124             (oui_info = g_hash_table_lookup(oui_info_table,
 125               GUINT_TO_POINTER(oui))) != NULL) {
 126                 /*
 127                  * Yes - use it.
 128                  */
 129                 hf = *oui_info->field_info->p_id;
 130                 subdissector_table = oui_info->table;
 131         } else {
 132                 /*
 133                  * No, use hf_ieee802a_pid for the PID and just dissect
 134                  * the payload as data.
 135                  */
 136                 hf = hf_ieee802a_pid;
 137                 subdissector_table = NULL;
 138         }
 139         if (tree)
 140                 proto_tree_add_uint(ieee802a_tree, hf, tvb, offset+3, 2, etype);
 141         next_tvb = tvb_new_subset(tvb, offset+5, -1, -1);
 142         if (subdissector_table != NULL) {
 143                 /* do lookup with the subdissector table */
 144                 if (dissector_try_port(subdissector_table, etype, next_tvb,
 145                     pinfo, tree))
 146                         return;
 147         }
 148         call_dissector(data_handle, next_tvb, pinfo, tree);
 149 }
 150
 151 void
 152 proto_register_ieee802a(void)
 153 {
 154         static hf_register_info hf[] = {
 155                 { &hf_ieee802a_oui,
 156                 { "Organization Code",  "ieee802a.oui", FT_UINT24, BASE_HEX,
 157                         VALS(oui_vals), 0x0, "", HFILL }},
 158
 159                 { &hf_ieee802a_pid,
 160                 { "Protocol ID", "ieee802a.pid", FT_UINT16, BASE_HEX,
 161                         NULL, 0x0, "", HFILL }}
 162         };
 163         static gint *ett[] = {
 164                 &ett_ieee802a,
 165         };
 166
 167         proto_ieee802a = proto_register_protocol("IEEE802a OUI Extended Ethertype", "IEEE802a", "ieee802a");
 168         proto_register_field_array(proto_ieee802a, hf, array_length(hf));
 169         proto_register_subtree_array(ett, array_length(ett));
 170 }
 171
 172 static void
 173 register_hf(gpointer key _U_, gpointer value, gpointer user_data _U_)
 174 {
 175         oui_info_t *info = value;
 176
 177         proto_register_field_array(proto_ieee802a, info->field_info, 1);
 178 }
 179
 180 void
 181 proto_reg_handoff_ieee802a(void)
 182 {
 183         dissector_handle_t ieee802a_handle;
 184
 185         data_handle = find_dissector("data");
 186
 187         ieee802a_handle = create_dissector_handle(dissect_ieee802a,
 188             proto_ieee802a);
 189         dissector_add("ethertype", ETHERTYPE_IEEE802_OUI_EXTENDED,
 190             ieee802a_handle);
 191
 192         /*
 193          * Register all the fields for PIDs for various OUIs.
 194          */
 195         if (oui_info_table != NULL)
 196                 g_hash_table_foreach(oui_info_table, register_hf, NULL);
 197 }