plugins/epan/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  * Wireshark - Network traffic analyzer
   9  * By Gerald Combs <gerald@wireshark.org>
  10  * Copyright 1999 Gerald Combs
  11  *
  12  * SPDX-License-Identifier: GPL-2.0-or-later
  13  */
  14
  15 /* Include files */
  16
  17 #include "config.h"
  18
  19 #include <epan/packet.h>
  20 #include <epan/expert.h>
  21 #include "crc.h"
  22 #include "wimax-int.h"
  23 #include "wimax_compact_dlmap_ie_decoder.h"
  24 #include "wimax_compact_ulmap_ie_decoder.h"
  25
  26 extern int proto_wimax;
  27
  28 static int proto_wimax_harq_map_decoder;
  29 static int ett_wimax_harq_map_decoder;
  30
  31 /* MASKs */
  32 #define LSB_NIBBLE_MASK      0x0F
  33
  34 /* HARQ MAP masks */
  35 #define WIMAX_HARQ_MAP_INDICATOR_MASK    0xE00000
  36 #define WIMAX_HARQ_UL_MAP_APPENDED_MASK  0x100000
  37 #define WIMAX_HARQ_MAP_RESERVED_MASK     0x080000
  38 #define WIMAX_HARQ_MAP_MSG_LENGTH_MASK   0x07FC00
  39 #define WIMAX_HARQ_MAP_DL_IE_COUNT_MASK  0x0003F0
  40 #define WIMAX_HARQ_MAP_MSG_LENGTH_SHIFT  10
  41 #define WIMAX_HARQ_MAP_DL_IE_COUNT_SHIFT 4
  42
  43 /* HARQ MAP display indexies */
  44 static int hf_harq_map_indicator;
  45 static int hf_harq_ul_map_appended;
  46 static int hf_harq_map_reserved;
  47 static int hf_harq_map_msg_length;
  48 static int hf_harq_dl_ie_count;
  49 static int hf_harq_map_msg_crc;
  50 static int hf_harq_map_msg_crc_status;
  51
  52 static expert_field ei_harq_map_msg_crc;
  53
  54
  55 /* Copied and renamed from proto.c because global value_strings don't work for plugins */
  56 static const value_string plugin_proto_checksum_vals[] = {
  57         { PROTO_CHECKSUM_E_BAD,        "Bad"  },
  58         { PROTO_CHECKSUM_E_GOOD,       "Good" },
  59         { PROTO_CHECKSUM_E_UNVERIFIED, "Unverified" },
  60         { PROTO_CHECKSUM_E_NOT_PRESENT, "Not present" },
  61
  62         { 0,        NULL }
  63 };
  64
  65 /* HARQ MAP message decoder */
  66 static int dissector_wimax_harq_map_decoder(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
  67 {
  68         unsigned i, offset = 0;
  69         unsigned tvb_len, length, dl_ie_count;
  70         unsigned ie_length;
  71         proto_item *harq_map_item = NULL;
  72         proto_tree *harq_map_tree = NULL;
  73         unsigned nibble_offset;
  74         proto_item *parent_item = NULL;
  75         unsigned ulmap_appended;
  76         uint32_t harq_map_msg_crc, calculated_crc;
  77         uint32_t first_24bits;
  78
  79         /* check the tvb reported length */
  80         tvb_len = tvb_reported_length(tvb);
  81         if(!tvb_len)
  82         {       /* do nothing if tvb is empty */
  83                 return 0;
  84         }
  85         /* Ensure the right payload type */
  86         first_24bits = tvb_get_ntoh24(tvb, offset);
  87         if((first_24bits & WIMAX_HARQ_MAP_INDICATOR_MASK) != WIMAX_HARQ_MAP_INDICATOR_MASK)
  88         {       /* do nothing if tvb is not a HARQ MAP message */
  89                 return 0;
  90         }
  91         /* update the info column */
  92         col_append_sep_str(pinfo->cinfo, COL_INFO, NULL, "HARQ-MAP Message: ");
  93         if (tree)
  94         {       /* we are being asked for details */
  95                 /* get the parent */
  96                 parent_item = proto_tree_get_parent(tree);
  97                 /* display HARQ-MAP Message and create subtree */
  98                 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);
  99                 harq_map_tree = proto_item_add_subtree(harq_map_item, ett_wimax_harq_map_decoder);
 100                 /* display the HARQ MAP Indicator */
 101                 proto_tree_add_item(harq_map_tree, hf_harq_map_indicator, tvb, offset, 3, ENC_BIG_ENDIAN);
 102                 /* display the HARQ MAp UL-MAP Appended */
 103                 proto_tree_add_item(harq_map_tree, hf_harq_ul_map_appended, tvb, offset, 3, ENC_BIG_ENDIAN);
 104                 /* display the reserved bit */
 105                 proto_tree_add_item(harq_map_tree, hf_harq_map_reserved, tvb, offset, 3, ENC_BIG_ENDIAN);
 106                 /* display the HARQ MAP message length */
 107                 proto_tree_add_item(harq_map_tree, hf_harq_map_msg_length, tvb, offset, 3, ENC_BIG_ENDIAN);
 108                 /* display the DL IE count */
 109                 proto_tree_add_item(harq_map_tree, hf_harq_dl_ie_count, tvb, offset, 3, ENC_BIG_ENDIAN);
 110                 /* get the message length */
 111                 /* XXX - make sure the length isn't smaller than the minimum */
 112                 length = ((first_24bits & WIMAX_HARQ_MAP_MSG_LENGTH_MASK) >> WIMAX_HARQ_MAP_MSG_LENGTH_SHIFT);
 113                 /* get the DL IE count */
 114                 dl_ie_count = ((first_24bits & WIMAX_HARQ_MAP_DL_IE_COUNT_MASK) >> WIMAX_HARQ_MAP_DL_IE_COUNT_SHIFT);
 115                 /* get the UL MAP appended */
 116                 ulmap_appended = (first_24bits & WIMAX_HARQ_UL_MAP_APPENDED_MASK);
 117
 118                 /* set the offsets to Compact DL-MAP IEs */
 119                 offset += 2;
 120                 nibble_offset = 1;
 121                 /* process the compact dl_map ies */
 122                 for(i=0; i<dl_ie_count; i++)
 123                 {       /* add the DL-MAp IEs info */
 124                         proto_item_append_text(parent_item, " - DL-MAP IEs");
 125                         /* decode Compact DL-MAP IEs */
 126                         ie_length = wimax_compact_dlmap_ie_decoder(harq_map_tree, pinfo, tvb, offset, nibble_offset);
 127                         offset += ((nibble_offset + ie_length) >> 1);
 128                         nibble_offset = ((nibble_offset + ie_length) & 1);
 129                 }
 130                 /* check if there exist the compact ul_map IEs */
 131                 if (ulmap_appended)
 132                 {       /* add the UL-MAp IEs info */
 133                         proto_item_append_text(parent_item, ",UL-MAP IEs");
 134                         /* process the compact ul_map ies */
 135                         while(offset < (length - (int)sizeof(harq_map_msg_crc)))
 136                         {       /* decode Compact UL-MAP IEs */
 137                                 ie_length = wimax_compact_ulmap_ie_decoder(harq_map_tree, pinfo, tvb, offset, nibble_offset);
 138                                 /* Prevent endless loop with erroneous data. */
 139                                 if (ie_length < 2)
 140                                         ie_length = 2;
 141                                 offset += ((nibble_offset + ie_length) >> 1);
 142                                 nibble_offset = ((nibble_offset + ie_length) & 1);
 143                         }
 144                 }
 145                 /* handle the padding */
 146                 if(nibble_offset)
 147                 {
 148                         /* add the Padding info */
 149                         proto_item_append_text(parent_item, ",Padding");
 150                         proto_tree_add_protocol_format(harq_map_tree, proto_wimax_harq_map_decoder, tvb, offset, 1, "Padding Nibble: 0x%x", (tvb_get_uint8(tvb, offset) & LSB_NIBBLE_MASK));
 151                 }
 152                 /* add the CRC info */
 153                 proto_item_append_text(parent_item, ",CRC");
 154                 /* calculate the HARQ MAM Message CRC */
 155                 if (length >= (int)sizeof(harq_map_msg_crc)) {
 156                         calculated_crc = wimax_mac_calc_crc32(tvb_get_ptr(tvb, 0, length - (int)sizeof(harq_map_msg_crc)), length - (int)sizeof(harq_map_msg_crc));
 157                         proto_tree_add_checksum(tree, tvb, length - (int)sizeof(harq_map_msg_crc), hf_harq_map_msg_crc, hf_harq_map_msg_crc_status, &ei_harq_map_msg_crc,
 158                                                                         pinfo, calculated_crc, ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY);
 159                 }
 160         }
 161         return tvb_captured_length(tvb);
 162 }
 163
 164 /* Register Wimax HARQ MAP Protocol */
 165 void wimax_proto_register_wimax_harq_map(void)
 166 {
 167         /* HARQ MAP display */
 168         static hf_register_info hf_harq_map[] =
 169         {
 170                 {
 171                         &hf_harq_map_indicator,
 172                         {"HARQ MAP Indicator", "wmx.harq_map.indicator", FT_UINT24, BASE_HEX, NULL, WIMAX_HARQ_MAP_INDICATOR_MASK, NULL, HFILL}
 173                 },
 174                 {
 175                         &hf_harq_ul_map_appended,
 176                         {"HARQ UL-MAP Appended", "wmx.harq_map.ul_map_appended", FT_UINT24, BASE_HEX, NULL, WIMAX_HARQ_UL_MAP_APPENDED_MASK, NULL, HFILL}
 177                 },
 178                 {
 179                         &hf_harq_map_reserved,
 180                         {"Reserved", "wmx.harq_map.reserved", FT_UINT24, BASE_HEX, NULL, WIMAX_HARQ_MAP_RESERVED_MASK, NULL, HFILL}
 181                 },
 182                 {
 183                         &hf_harq_map_msg_length,
 184                         {"Map Message Length", "wmx.harq_map.msg_length", FT_UINT24, BASE_DEC, NULL, WIMAX_HARQ_MAP_MSG_LENGTH_MASK, NULL, HFILL}
 185                 },
 186                 {
 187                         &hf_harq_dl_ie_count,
 188                         {"DL IE Count", "wmx.harq_map.dl_ie_count", FT_UINT24, BASE_DEC, NULL, WIMAX_HARQ_MAP_DL_IE_COUNT_MASK, NULL, HFILL}
 189                 },
 190                 {
 191                         &hf_harq_map_msg_crc,
 192                         {"HARQ MAP Message CRC", "wmx.harq_map.msg_crc", FT_UINT32, BASE_HEX, NULL, 0x0, NULL, HFILL}
 193                 },
 194                 {
 195                         &hf_harq_map_msg_crc_status,
 196                         {"HARQ MAP Message CRC Status", "wmx.harq_map.msg_crc.status", FT_UINT8, BASE_NONE, VALS(plugin_proto_checksum_vals), 0x0, NULL, HFILL}
 197                 },
 198         };
 199
 200         /* Setup protocol subtree array */
 201         static int *ett[] =
 202         {
 203                 &ett_wimax_harq_map_decoder,
 204         };
 205
 206         static ei_register_info ei[] = {
 207                 { &ei_harq_map_msg_crc, { "wmx.harq_map.bad_checksum", PI_CHECKSUM, PI_ERROR, "Bad checksum", EXPFILL }},
 208         };
 209
 210         expert_module_t* expert_harq_map;
 211
 212         proto_wimax_harq_map_decoder = proto_wimax;
 213
 214         proto_register_subtree_array(ett, array_length(ett));
 215         proto_register_field_array(proto_wimax_harq_map_decoder, hf_harq_map, array_length(hf_harq_map));
 216         expert_harq_map = expert_register_protocol(proto_wimax_harq_map_decoder);
 217         expert_register_field_array(expert_harq_map, ei, array_length(ei));
 218
 219         register_dissector("wimax_harq_map_handler", dissector_wimax_harq_map_decoder, proto_wimax_harq_map_decoder);
 220 }
 221
 222 /*
 223  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 224  *
 225  * Local variables:
 226  * c-basic-offset: 8
 227  * tab-width: 8
 228  * indent-tabs-mode: t
 229  * End:
 230  *
 231  * vi: set shiftwidth=8 tabstop=8 noexpandtab:
 232  * :indentSize=8:tabSize=8:noTabs=false:
 233  */