plugins/wimax/wimax_harq_map_decoder.c

   1 /* wimax_harq_map_decoder.c
   2  * WiMax HARQ Map Message decoder
   3  *
   4  * Copyright (c) 2007 by Intel Corporation.
   5  *
   6  * Author: Lu Pan <lu.pan@intel.com>
   7  *
   8  * $Id$
   9  *
  10  * Wireshark - Network traffic analyzer
  11  * By Gerald Combs <gerald@wireshark.org>
  12  * Copyright 1999 Gerald Combs
  13  *
  14  * This program is free software; you can redistribute it and/or
  15  * modify it under the terms of the GNU General Public License
  16  * as published by the Free Software Foundation; either version 2
  17  * of the License, or (at your option) any later version.
  18  *
  19  * This program is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with this program; if not, write to the Free Software
  26  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  27  */
  28
  29 /* Include files */
  30
  31 #ifdef HAVE_CONFIG_H
  32 #include "config.h"
  33 #endif
  34
  35 #include <glib.h>
  36 #include <epan/packet.h>
  37 #include "crc.h"
  38
  39 extern guint wimax_compact_dlmap_ie_decoder(proto_tree *tree, packet_info *pinfo, tvbuff_t *tvb, guint offset, guint nibble_offset);
  40 extern guint wimax_compact_ulmap_ie_decoder(proto_tree *tree, packet_info *pinfo, tvbuff_t *tvb, guint offset, guint nibble_offset);
  41
  42
  43 extern gint proto_wimax;
  44
  45 /* forward reference */
  46 void dissector_wimax_harq_map_decoder(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree);
  47
  48 static gint proto_wimax_harq_map_decoder = -1;
  49 static gint ett_wimax_harq_map_decoder = -1;
  50
  51 /* MASKs */
  52 #define LSB_NIBBLE_MASK      0x0F
  53
  54 /* HARQ MAP masks */
  55 #define WIMAX_HARQ_MAP_INDICATOR_MASK    0xE00000
  56 #define WIMAX_HARQ_UL_MAP_APPENDED_MASK  0x100000
  57 #define WIMAX_HARQ_MAP_RESERVED_MASK     0x080000
  58 #define WIMAX_HARQ_MAP_MSG_LENGTH_MASK   0x07FC00
  59 #define WIMAX_HARQ_MAP_DL_IE_COUNT_MASK  0x0003F0
  60 #define WIMAX_HARQ_MAP_MSG_LENGTH_SHIFT  10
  61 #define WIMAX_HARQ_MAP_DL_IE_COUNT_SHIFT 4
  62
  63 /* HARQ MAP display indexies */
  64 static gint hf_harq_map_indicator = -1;
  65 static gint hf_harq_ul_map_appended = -1;
  66 static gint hf_harq_map_reserved = -1;
  67 static gint hf_harq_map_msg_length = -1;
  68 static gint hf_harq_dl_ie_count = -1;
  69 static gint hf_harq_map_msg_crc = -1;
  70
  71
  72 /* HARQ MAP message decoder */
  73 void dissector_wimax_harq_map_decoder(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
  74 {
  75         guint i, offset = 0;
  76         guint tvb_len, length, dl_ie_count;
  77         guint ie_length;
  78         proto_item *harq_map_item = NULL;
  79         proto_tree *harq_map_tree = NULL;
  80         guint nibble_offset;
  81         proto_item *parent_item = NULL;
  82         proto_item *it = NULL;
  83         guint ulmap_appended;
  84         guint32 harq_map_msg_crc, calculated_crc;
  85         guint32 first_24bits;
  86
  87         /* check the tvb reported length */
  88         tvb_len = tvb_reported_length(tvb);
  89         if(!tvb_len)
  90         {       /* do nothing if tvb is empty */
  91                 return;
  92         }
  93         /* Ensure the right payload type */
  94         first_24bits = tvb_get_ntoh24(tvb, offset);
  95         if((first_24bits & WIMAX_HARQ_MAP_INDICATOR_MASK) != WIMAX_HARQ_MAP_INDICATOR_MASK)
  96         {       /* do nothing if tvb is not a HARQ MAP message */
  97                 return;
  98         }
  99         /* update the info column */
 100         if (check_col(pinfo->cinfo, COL_INFO))
 101         {
 102                 col_append_sep_str(pinfo->cinfo, COL_INFO, NULL, "HARQ-MAP Message: ");
 103         }
 104         if (tree)
 105         {       /* we are being asked for details */
 106                 /* get the parent */
 107                 parent_item = proto_tree_get_parent(tree);
 108                 /* display HARQ-MAP Message and create subtree */
 109                 harq_map_item = proto_tree_add_protocol_format(tree, proto_wimax_harq_map_decoder, tvb, offset, tvb_len, "HARQ-MAP Message (%u bytes)", tvb_len);
 110                 harq_map_tree = proto_item_add_subtree(harq_map_item, ett_wimax_harq_map_decoder);
 111                 /* display the HARQ MAP Indicator */
 112                 proto_tree_add_item(harq_map_tree, hf_harq_map_indicator, tvb, offset, 3, FALSE);
 113                 /* display the HARQ MAp UL-MAP Appended */
 114                 proto_tree_add_item(harq_map_tree, hf_harq_ul_map_appended, tvb, offset, 3, FALSE);
 115                 /* display the reserved bit */
 116                 proto_tree_add_item(harq_map_tree, hf_harq_map_reserved, tvb, offset, 3, FALSE);
 117                 /* display the HARQ MAP message length */
 118                 proto_tree_add_item(harq_map_tree, hf_harq_map_msg_length, tvb, offset, 3, FALSE);
 119                 /* display the DL IE count */
 120                 proto_tree_add_item(harq_map_tree, hf_harq_dl_ie_count, tvb, offset, 3, FALSE);
 121                 /* get the message length */
 122                 length = ((first_24bits & WIMAX_HARQ_MAP_MSG_LENGTH_MASK) >> WIMAX_HARQ_MAP_MSG_LENGTH_SHIFT);
 123                 /* get the DL IE count */
 124                 dl_ie_count = ((first_24bits & WIMAX_HARQ_MAP_DL_IE_COUNT_MASK) >> WIMAX_HARQ_MAP_DL_IE_COUNT_SHIFT);
 125                 /* get the UL MAP appended */
 126                 ulmap_appended = (first_24bits & WIMAX_HARQ_UL_MAP_APPENDED_MASK);
 127                 if (parent_item == NULL || PITEM_FINFO(parent_item) == NULL)
 128                 {
 129                         parent_item = harq_map_item; /* Prevent crash */
 130                 }
 131                 /* set the offsets to Compact DL-MAP IEs */
 132                 offset += 2;
 133                 nibble_offset = 1;
 134                 /* process the compact dl_map ies */
 135                 for(i=0; i<dl_ie_count; i++)
 136                 {       /* add the DL-MAp IEs info */
 137                         proto_item_append_text(parent_item, " - DL-MAP IEs");
 138                         /* decode Compact DL-MAP IEs */
 139                         ie_length = wimax_compact_dlmap_ie_decoder(harq_map_tree, pinfo, tvb, offset, nibble_offset);
 140                         offset += ((nibble_offset + ie_length) >> 1);
 141                         nibble_offset = ((nibble_offset + ie_length) & 1);
 142                 }
 143                 /* check if there exist the compact ul_map IEs */
 144                 if (ulmap_appended)
 145                 {       /* add the UL-MAp IEs info */
 146                         proto_item_append_text(parent_item, ",UL-MAP IEs");
 147                         /* process the compact ul_map ies */
 148                         while(offset < (length - sizeof(harq_map_msg_crc)))
 149                         {       /* decode Compact UL-MAP IEs */
 150                                 ie_length = wimax_compact_ulmap_ie_decoder(harq_map_tree, pinfo, tvb, offset, nibble_offset);
 151                                 /* Prevent endless loop with erroneous data. */
 152                                 if (ie_length < 2)
 153                                         ie_length = 2;
 154                                 offset += ((nibble_offset + ie_length) >> 1);
 155                                 nibble_offset = ((nibble_offset + ie_length) & 1);
 156                         }
 157                 }
 158                 /* handle the padding */
 159                 if(nibble_offset)
 160                 {
 161                         /* add the Padding info */
 162                         proto_item_append_text(parent_item, ",Padding");
 163                         proto_tree_add_protocol_format(harq_map_tree, proto_wimax_harq_map_decoder, tvb, offset, 1, "Padding Nibble: 0x%x", (tvb_get_guint8(tvb, offset) & LSB_NIBBLE_MASK));
 164                 }
 165                 /* add the CRC info */
 166                 proto_item_append_text(parent_item, ",CRC");
 167                 /* get the CRC */
 168                 harq_map_msg_crc = tvb_get_ntohl(tvb, length - sizeof(harq_map_msg_crc));
 169                 /* calculate the HARQ MAM Message CRC */
 170                 calculated_crc = wimax_mac_calc_crc32(tvb_get_ptr(tvb, 0, length - sizeof(harq_map_msg_crc)), length - sizeof(harq_map_msg_crc));
 171                 /* display the CRC */
 172                 it = proto_tree_add_item(harq_map_tree, hf_harq_map_msg_crc, tvb, length - sizeof(harq_map_msg_crc), sizeof(harq_map_msg_crc), FALSE);
 173                 /* verify the CRC */
 174                 if (harq_map_msg_crc != calculated_crc)
 175                 {
 176                         proto_item_append_text(it, " - incorrect! (should be: 0x%x)", calculated_crc);
 177                 }
 178         }
 179 }
 180
 181 /* Register Wimax HARQ MAP Protocol */
 182 void proto_register_wimax_harq_map(void)
 183 {
 184         /* HARQ MAP display */
 185         static hf_register_info hf_harq_map[] =
 186         {
 187                 {
 188                         &hf_harq_map_indicator,
 189                         {"HARQ MAP Indicator", "wmx.harq_map.indicator", FT_UINT24, BASE_HEX, NULL, WIMAX_HARQ_MAP_INDICATOR_MASK, NULL, HFILL}
 190                 },
 191                 {
 192                         &hf_harq_ul_map_appended,
 193                         {"HARQ UL-MAP Appended", "wmx.harq_map.ul_map_appended", FT_UINT24, BASE_HEX, NULL, WIMAX_HARQ_UL_MAP_APPENDED_MASK, NULL, HFILL}
 194                 },
 195                 {
 196                         &hf_harq_map_reserved,
 197                         {"Reserved", "wmx.harq_map.reserved", FT_UINT24, BASE_HEX, NULL, WIMAX_HARQ_MAP_RESERVED_MASK, NULL, HFILL}
 198                 },
 199                 {
 200                         &hf_harq_map_msg_length,
 201                         {"Map Message Length", "wmx.harq_map.msg_length", FT_UINT24, BASE_DEC, NULL, WIMAX_HARQ_MAP_MSG_LENGTH_MASK, NULL, HFILL}
 202                 },
 203                 {
 204                         &hf_harq_dl_ie_count,
 205                         {"DL IE Count", "wmx.harq_map.dl_ie_count", FT_UINT24, BASE_DEC, NULL, WIMAX_HARQ_MAP_DL_IE_COUNT_MASK, NULL, HFILL}
 206                 },
 207                 {
 208                         &hf_harq_map_msg_crc,
 209                         {"HARQ MAP Message CRC", "wmx.harq_map.msg_crc", FT_UINT32, BASE_HEX, NULL, 0x0, NULL, HFILL}
 210                 }
 211         };
 212
 213         /* Setup protocol subtree array */
 214         static gint *ett[] =
 215                 {
 216                         &ett_wimax_harq_map_decoder,
 217                 };
 218
 219         proto_wimax_harq_map_decoder = proto_wimax;
 220
 221         proto_register_subtree_array(ett, array_length(ett));
 222         proto_register_field_array(proto_wimax_harq_map_decoder, hf_harq_map, array_length(hf_harq_map));
 223 }