epan/dissectors/packet-dvb-data-mpe.c

   1 /* packet-dvb-data-mpe.c
   2  * Routines for DVB-DATA (ETSI EN 301 192) MultiProtocol Encapsulation
   3  * Copyright 2012, Guy Martin <gmsoft@tuxicoman.be>
   4  *
   5  * Wireshark - Network traffic analyzer
   6  * By Gerald Combs <gerald@wireshark.org>
   7  * Copyright 1998 Gerald Combs
   8  *
   9  * SPDX-License-Identifier: GPL-2.0-or-later
  10  */
  11
  12 #include "config.h"
  13
  14 #include <epan/packet.h>
  15 #include <epan/expert.h>
  16 #include <epan/to_str.h>
  17 #include <epan/tfs.h>
  18 #include "packet-mpeg-sect.h"
  19
  20 void proto_register_dvb_data_mpe(void);
  21 void proto_reg_handoff_dvb_data_mpe(void);
  22
  23 static int proto_dvb_data_mpe;
  24 static int hf_dvb_data_mpe_reserved;
  25 static int hf_dvb_data_mpe_payload_scrambling_control;
  26 static int hf_dvb_data_mpe_address_scrambling_control;
  27 static int hf_dvb_data_mpe_llc_snap_flag;
  28 static int hf_dvb_data_mpe_current_next_indicator;
  29 static int hf_dvb_data_mpe_section_number;
  30 static int hf_dvb_data_mpe_last_section_number;
  31 static int hf_dvb_data_mpe_dst_mac;
  32 static int hf_dvb_data_mpe_dst_mac_scrambled;
  33
  34 static int ett_dvb_data_mpe;
  35
  36 static expert_field ei_dvb_data_mpe_reserved_not_one;
  37 static expert_field ei_dvb_data_mpe_payload_scrambled;
  38 static expert_field ei_dvb_data_mpe_address_scrambled;
  39
  40 static dissector_handle_t dvb_data_mpe_handle;
  41
  42 static dissector_handle_t ip_handle;
  43 static dissector_handle_t llc_handle;
  44
  45 #define DVB_DATA_MPE_RESERVED_MASK                0xC0
  46 #define DVB_DATA_MPE_PAYLOAD_SCRAMBLING_MASK      0x30
  47 #define DVB_DATA_MPE_ADDRESS_SCRAMBLING_MASK      0x0C
  48 #define DVB_DATA_MPE_LLC_SNAP_FLAG_MASK           0x02
  49 #define DVB_DATA_MPE_CURRENT_NEXT_INDICATOR_MASK  0x01
  50
  51 /* Field positions for the MAC Address */
  52 /* It is split into two chunks, one of two octets and a second
  53  * one of four octets. Also, the octets are in reverse order. */
  54 #define DVB_DATA_MPE_DST_MAC_FIRST 3
  55 #define DVB_DATA_MPE_DST_MAC_SECOND 8
  56
  57 static const value_string dvb_data_mpe_scrambling_vals[] = {
  58     { 0, "Unscrambled" },
  59     { 1, "Defined by service" },
  60     { 2, "Defined by service" },
  61     { 3, "Defined by service" },
  62     { 0, NULL }
  63 };
  64
  65 static int
  66 dissect_dvb_data_mpe(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
  67 {
  68
  69     unsigned    offset = 0, tot_len = 0;
  70     uint32_t    reserved, address_scrambling, payload_scrambling, llc_snap_flag;
  71     int         i;
  72
  73     proto_item *ti;
  74     proto_tree *dvb_data_mpe_tree;
  75     unsigned char     *dst = (unsigned char*)wmem_alloc(pinfo->pool, 6);
  76     address     dst_addr;
  77     tvbuff_t   *data_tvb;
  78
  79     /* The TVB should start right after the section_length in the Section packet */
  80
  81     col_set_str(pinfo->cinfo, COL_PROTOCOL, "DVB-DATA");
  82     col_set_str(pinfo->cinfo, COL_INFO, "MultiProtocol Encapsulation");
  83
  84     ti = proto_tree_add_item(tree, proto_dvb_data_mpe, tvb, offset, -1, ENC_NA);
  85     dvb_data_mpe_tree = proto_item_add_subtree(ti, ett_dvb_data_mpe);
  86
  87     offset += packet_mpeg_sect_header(tvb, offset, dvb_data_mpe_tree, &tot_len, NULL);
  88
  89
  90     /* Parse the DMC-CC private section header */
  91
  92     dst[5] = tvb_get_uint8(tvb, offset);
  93     offset += 1;
  94     dst[4] = tvb_get_uint8(tvb, offset);
  95     offset += 1;
  96
  97     ti = proto_tree_add_item_ret_uint(dvb_data_mpe_tree, hf_dvb_data_mpe_reserved,     tvb, offset, 1, ENC_BIG_ENDIAN, &reserved);
  98     if (reserved != 3) {
  99         expert_add_info(pinfo, ti, &ei_dvb_data_mpe_reserved_not_one);
 100     }
 101     ti = proto_tree_add_item_ret_uint(dvb_data_mpe_tree, hf_dvb_data_mpe_payload_scrambling_control, tvb, offset, 1, ENC_BIG_ENDIAN, &payload_scrambling);
 102     if (payload_scrambling) {
 103         expert_add_info(pinfo, ti, &ei_dvb_data_mpe_payload_scrambled);
 104     }
 105     proto_tree_add_item_ret_uint(dvb_data_mpe_tree, hf_dvb_data_mpe_address_scrambling_control, tvb, offset, 1, ENC_BIG_ENDIAN, &address_scrambling);
 106     proto_tree_add_item_ret_uint(dvb_data_mpe_tree, hf_dvb_data_mpe_llc_snap_flag,     tvb, offset, 1, ENC_BIG_ENDIAN, &llc_snap_flag);
 107     proto_tree_add_item(dvb_data_mpe_tree, hf_dvb_data_mpe_current_next_indicator,     tvb, offset, 1, ENC_BIG_ENDIAN);
 108     offset += 1;
 109
 110     proto_tree_add_item(dvb_data_mpe_tree, hf_dvb_data_mpe_section_number,             tvb, offset, 1, ENC_BIG_ENDIAN);
 111     offset += 1;
 112
 113     proto_tree_add_item(dvb_data_mpe_tree, hf_dvb_data_mpe_last_section_number,        tvb, offset, 1, ENC_BIG_ENDIAN);
 114     offset += 1;
 115
 116     for (i = 3; i >= 0; i--) {
 117         dst[i] = tvb_get_uint8(tvb, offset);
 118         offset += 1;
 119     }
 120
 121     if (address_scrambling) {
 122         ti = proto_tree_add_bytes_with_length(dvb_data_mpe_tree, hf_dvb_data_mpe_dst_mac_scrambled, tvb, DVB_DATA_MPE_DST_MAC_FIRST, 2, dst, 6);
 123         expert_add_info(pinfo, ti, &ei_dvb_data_mpe_address_scrambled);
 124     } else {
 125         ti = proto_tree_add_ether(dvb_data_mpe_tree, hf_dvb_data_mpe_dst_mac, tvb, DVB_DATA_MPE_DST_MAC_FIRST, 2, dst);
 126         set_address(&dst_addr, AT_ETHER, 6, dst);
 127         col_add_str(pinfo->cinfo, COL_RES_DL_DST, address_to_str(pinfo->pool, &dst_addr));
 128     }
 129     /* Extend the highlighting for the second chunk. */
 130     proto_tree_set_appendix(ti, tvb, DVB_DATA_MPE_DST_MAC_SECOND, 4);
 131
 132     data_tvb = tvb_new_subset_remaining(tvb, offset);
 133
 134     if (payload_scrambling) {
 135         call_data_dissector(data_tvb, pinfo, tree);
 136     } else if (llc_snap_flag) {
 137         call_dissector(llc_handle, data_tvb, pinfo, tree);
 138     } else {
 139         call_dissector(ip_handle, data_tvb, pinfo, tree);
 140     }
 141
 142     packet_mpeg_sect_crc(tvb, pinfo, dvb_data_mpe_tree, 0, tot_len - 1);
 143     return tvb_captured_length(tvb);
 144 }
 145
 146 void
 147 proto_register_dvb_data_mpe(void)
 148 {
 149
 150     static hf_register_info hf[] = {
 151
 152         /* DSM-CC common fields */
 153         { &hf_dvb_data_mpe_reserved, {
 154             "Reserved", "dvb_data_mpe.reserved",
 155             FT_UINT8, BASE_HEX, NULL, DVB_DATA_MPE_RESERVED_MASK, NULL, HFILL
 156         } },
 157
 158         { &hf_dvb_data_mpe_payload_scrambling_control, {
 159             "Payload Scrambling Control", "dvb_data_mpe.pload_scrambling",
 160             FT_UINT8, BASE_HEX, VALS(dvb_data_mpe_scrambling_vals),
 161             DVB_DATA_MPE_PAYLOAD_SCRAMBLING_MASK, NULL, HFILL
 162         } },
 163
 164         { &hf_dvb_data_mpe_address_scrambling_control, {
 165             "Address Scrambling Control", "dvb_data_mpe.addr_scrambling",
 166             FT_UINT8, BASE_HEX, VALS(dvb_data_mpe_scrambling_vals),
 167             DVB_DATA_MPE_ADDRESS_SCRAMBLING_MASK, NULL, HFILL
 168         } },
 169
 170         { &hf_dvb_data_mpe_llc_snap_flag, {
 171             "LLC SNAP Flag", "dvb_data_mpe.llc_snap_flag",
 172             FT_UINT8, BASE_HEX, NULL, DVB_DATA_MPE_LLC_SNAP_FLAG_MASK, NULL, HFILL
 173         } },
 174
 175         { &hf_dvb_data_mpe_current_next_indicator, {
 176             "Current/Next Indicator", "mpeg_sect.cur_next_ind",
 177             FT_BOOLEAN, 8, TFS(&tfs_current_not_yet), DVB_DATA_MPE_CURRENT_NEXT_INDICATOR_MASK, NULL, HFILL
 178         } },
 179
 180         { &hf_dvb_data_mpe_section_number, {
 181             "Section Number", "dvb_data_mpe.sect_num",
 182             FT_UINT8, BASE_DEC, NULL, 0, NULL, HFILL
 183         } },
 184
 185         { &hf_dvb_data_mpe_last_section_number, {
 186             "Last Section Number", "dvb_data_mpe.last_sect_num",
 187             FT_UINT8, BASE_DEC, NULL, 0, NULL, HFILL
 188         } },
 189
 190         { &hf_dvb_data_mpe_dst_mac, {
 191             "Destination MAC address", "dvb_data_mpe.dst_mac",
 192             FT_ETHER, BASE_NONE, NULL, 0, NULL, HFILL
 193         } },
 194
 195         { &hf_dvb_data_mpe_dst_mac_scrambled, {
 196             "Destination MAC address (scrambled)",
 197             "dvb_data_mpe.dst_mac.scrambled",
 198             FT_BYTES, SEP_COLON, NULL, 0, NULL, HFILL
 199         } },
 200
 201     };
 202
 203     static int *ett[] = {
 204         &ett_dvb_data_mpe,
 205     };
 206
 207     expert_module_t *expert_dvb_data_mpe;
 208     static ei_register_info ei[] = {
 209         { &ei_dvb_data_mpe_reserved_not_one,
 210             { "dvb_data_mpe.reserved.not_one", PI_PROTOCOL, PI_WARN,
 211                 "Reserved bits not all ones", EXPFILL }},
 212         { &ei_dvb_data_mpe_address_scrambled,
 213             { "dvb_data_mpe.address_scrambled", PI_UNDECODED, PI_WARN,
 214                 "Cannot descramble destination MAC address (user private scrambling)", EXPFILL }},
 215         { &ei_dvb_data_mpe_payload_scrambled,
 216             { "dvb_data_mpe.payload.scrambled", PI_UNDECODED, PI_WARN,
 217                 "Cannot descramble payload (user private scrambling)", EXPFILL }},
 218     };
 219
 220     proto_dvb_data_mpe = proto_register_protocol("DVB-DATA MultiProtocol Encapsulation", "DVB-DATA MPE", "dvb_data_mpe");
 221     proto_register_field_array(proto_dvb_data_mpe, hf, array_length(hf));
 222     expert_dvb_data_mpe = expert_register_protocol(proto_dvb_data_mpe);
 223     expert_register_field_array(expert_dvb_data_mpe, ei, array_length(ei));
 224
 225     proto_register_subtree_array(ett, array_length(ett));
 226
 227     dvb_data_mpe_handle = register_dissector("dvb_data_mpe", dissect_dvb_data_mpe, proto_dvb_data_mpe);
 228 }
 229
 230
 231 void
 232 proto_reg_handoff_dvb_data_mpe(void)
 233 {
 234     dissector_add_uint("mpeg_sect.tid", DVB_DATA_MPE_TID, dvb_data_mpe_handle);
 235
 236     ip_handle  = find_dissector_add_dependency("ip", proto_dvb_data_mpe);
 237     llc_handle = find_dissector_add_dependency("llc", proto_dvb_data_mpe);
 238
 239 }
 240
 241 /*
 242  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 243  *
 244  * Local variables:
 245  * c-basic-offset: 4
 246  * tab-width: 8
 247  * indent-tabs-mode: nil
 248  * End:
 249  *
 250  * vi: set shiftwidth=4 tabstop=8 expandtab:
 251  * :indentSize=4:tabSize=8:noTabs=true:
 252  */