epan/dissectors/packet-gsm_abis_tfp.c

   1 /* packet-gsm_abis_tfp.c
   2  * Routines for packet dissection of Ericsson GSM A-bis TFP
   3  * (Traffic Forwarding Protocol)
   4  * Copyright 2010-2016 by Harald Welte <laforge@gnumonks.org>
   5  *
   6  * TFP is an Ericsson-specific packetized version of replacing TRAU
   7  * frames on 8k/16k E1 sub-slots with a paketized frame format which
   8  * can be transported over LAPD on a SuperChannel (E1 timeslot bundle)
   9  * or L2TP.
  10  *
  11  * Wireshark - Network traffic analyzer
  12  * By Gerald Combs <gerald@wireshark.org>
  13  * Copyright 1998 Gerald Combs
  14  *
  15  * SPDX-License-Identifier: GPL-2.0-or-later
  16  */
  17
  18 #include "config.h"
  19
  20 #include <epan/packet.h>
  21 #include <epan/prefs.h>
  22
  23 void proto_register_abis_tfp(void);
  24 void proto_reg_handoff_abis_tfp(void);
  25
  26 enum {
  27         SUB_DATA,
  28
  29         SUB_MAX
  30 };
  31
  32 static dissector_handle_t tfp_handle;
  33 static dissector_handle_t sub_handles[SUB_MAX];
  34
  35 /* initialize the protocol and registered fields */
  36 static int proto_abis_tfp;
  37
  38 /* TFP header */
  39 static int hf_tfp_hdr_atsr;
  40 static int hf_tfp_hdr_slot_rate;
  41 static int hf_tfp_hdr_seq_nr;
  42 static int hf_tfp_hdr_delay_info;
  43 static int hf_tfp_hdr_p;
  44 static int hf_tfp_hdr_s;
  45 static int hf_tfp_hdr_m;
  46 static int hf_tfp_hdr_frame_type;
  47 static int hf_tfp_amr_rate;
  48
  49 /* initialize the subtree pointers */
  50 static int ett_tfp;
  51
  52 static const value_string tfp_slot_rate_vals[] = {
  53         { 0,    "Full Rate (16kbps)" },
  54         { 1,    "Sub-Channel 0 (8kbps)" },
  55         { 2,    "Sub-Channel 1 (8kbps)" },
  56         { 3,    "Reserved" },
  57         { 0, NULL }
  58 };
  59
  60 #define TFP_PACKED_NONE         0
  61 #define TFP_PACKED_SCHEME_1     1
  62
  63 static const value_string tfp_packed_vals[] = {
  64         { 0,    "Not Packed" },
  65         { 1,    "Packing Scheme 1" },
  66         { 0, NULL }
  67 };
  68
  69 static const value_string tfp_frame_type_vals[] = {
  70         /* 8k */
  71         { 0,    "TFP-AMR-IND" },
  72         { 1,    "TFP-SCCE-AMR-IND" },
  73         { 2,    "TFP-HR-IND" },
  74         /* 16k */
  75         { 0x80, "TFP-AMR-IND" },
  76         { 0x81, "TFP-SCCE-AMR-IND" },
  77         { 0x82, "TFP-FR-IND" },
  78         { 0x83, "TFP-EFR-IND" },
  79         { 0x84, "TFP-SCCE-EFR-IND" },
  80         { 0, NULL }
  81 };
  82
  83 static const value_string tfp_amr_len_rate_vals[] = {
  84         {  1, "SID_FIRST, ONSET, No speech/data" },
  85         {  5, "SID_UPDATE, SID_BAD" },
  86         { 12, "4.75k" },
  87         { 13, "5.15k" },
  88         { 15, "5.90k" },
  89         { 17, "6.70k" },
  90         { 19, "7.40k" },
  91         { 20, "7.95k" },
  92         { 26, "10.2k" },
  93         { 31, "12.2k" },
  94         { 0, NULL }
  95 };
  96
  97 static int
  98 dissect_abis_tfp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
  99 {
 100         proto_item *ti;
 101         proto_tree *tfp_tree;
 102         int offset = 0;
 103         uint32_t slot_rate, frame_bits, atsr, seq_nr;
 104         uint8_t ftype;
 105         tvbuff_t *next_tvb;
 106         int len_remain;
 107
 108         col_set_str(pinfo->cinfo, COL_PROTOCOL, "TFP");
 109
 110         ti = proto_tree_add_item(tree, proto_abis_tfp, tvb, 0, -1, ENC_NA);
 111         tfp_tree = proto_item_add_subtree(ti, ett_tfp);
 112
 113         proto_tree_add_item_ret_uint(tfp_tree, hf_tfp_hdr_atsr, tvb, offset, 2, ENC_BIG_ENDIAN, &atsr);
 114         proto_tree_add_item_ret_uint(tfp_tree, hf_tfp_hdr_slot_rate, tvb, offset, 2, ENC_BIG_ENDIAN, &slot_rate);
 115         proto_tree_add_item_ret_uint(tfp_tree, hf_tfp_hdr_seq_nr, tvb, offset, 2, ENC_BIG_ENDIAN, &seq_nr);
 116         proto_tree_add_item(tfp_tree, hf_tfp_hdr_delay_info, tvb, offset+1, 2, ENC_BIG_ENDIAN);
 117         proto_tree_add_item(tfp_tree, hf_tfp_hdr_p, tvb, offset+1, 2, ENC_BIG_ENDIAN);
 118         proto_tree_add_item(tfp_tree, hf_tfp_hdr_s, tvb, offset+2, 1, ENC_NA);
 119         proto_tree_add_item(tfp_tree, hf_tfp_hdr_m, tvb, offset+2, 1, ENC_NA);
 120         /* Frame Type depends on Slot Rate */
 121         ftype = tvb_get_uint8(tvb, offset+2) & 0x1E;
 122         if (slot_rate == 0)
 123                 ftype |= 0x80;
 124         proto_tree_add_uint_format_value(tfp_tree, hf_tfp_hdr_frame_type, tvb, offset+2, 1, ftype, "%s",
 125                                          val_to_str(ftype, tfp_frame_type_vals, "Unknown (%u)"));
 126         offset += 2;
 127
 128         col_append_fstr(pinfo->cinfo, COL_INFO, "TS=%u, Seq=%u, %s, %s ", atsr, seq_nr,
 129                         val_to_str(slot_rate, tfp_slot_rate_vals, "Unknown (%u)"),
 130                         val_to_str(ftype, tfp_frame_type_vals, "Unknown (%u)"));
 131
 132         /* check for Tail bit == 1, iterate over further octests */
 133         while ((tvb_get_uint8(tvb, offset) & 0x01) == 0)
 134                 offset++;
 135         offset++;
 136
 137         switch (ftype & 0x7F) {
 138         case 0: /* TFP-AMR.ind */
 139                 len_remain = tvb_captured_length_remaining(tvb, offset);
 140                 proto_tree_add_uint(tfp_tree, hf_tfp_amr_rate, tvb, offset, 0, len_remain);
 141                 break;
 142         case 1: /* TFP-SCCE-AMR.ind */
 143                 break;
 144         case 2: /* TFP-HR.ind */
 145                 break;
 146         case 3: /* TFP-EFR.ind */
 147                 break;
 148         case 4: /* TFP-SCCE-EFR.ind */
 149                 break;
 150         }
 151
 152         /* FIXME: implement packed frame support */
 153         if (slot_rate == 0)
 154                 frame_bits = 320;
 155         else
 156                 frame_bits = 160;
 157         next_tvb = tvb_new_subset_length(tvb, offset, frame_bits/8);
 158         call_dissector(sub_handles[SUB_DATA], next_tvb, pinfo, tree);
 159
 160         return offset;
 161 }
 162
 163 void
 164 proto_register_abis_tfp(void)
 165 {
 166         static hf_register_info hf[] = {
 167                 { &hf_tfp_hdr_atsr,
 168                         { "Air Timeslot Resource", "gsm_abis_tfp.atsr",
 169                           FT_UINT16, BASE_DEC, NULL, 0xe000,
 170                           NULL, HFILL }
 171                 },
 172                 { &hf_tfp_hdr_slot_rate,
 173                         { "Slot Rate", "gsm_abis_tfp.slot_rate",
 174                           FT_UINT16, BASE_DEC, VALS(tfp_slot_rate_vals), 0x1800,
 175                           NULL, HFILL }
 176                 },
 177                 { &hf_tfp_hdr_seq_nr,
 178                         { "Sequence Number", "gsm_abis_tfp.seq_nr",
 179                           FT_UINT16, BASE_DEC, NULL, 0x07c0,
 180                           NULL, HFILL }
 181                 },
 182                 { &hf_tfp_hdr_delay_info,
 183                         { "Delay Information (ms)", "gsm_abis_tfp.delay_info",
 184                           FT_UINT16, BASE_DEC, NULL, 0x003e,
 185                           NULL, HFILL }
 186                 },
 187                 { &hf_tfp_hdr_p,
 188                         { "Packing Scheme", "gsm_abis_tfp.packing_scheme",
 189                           FT_UINT16, BASE_DEC, VALS(tfp_packed_vals), 0x0180,
 190                           NULL, HFILL }
 191                 },
 192                 { &hf_tfp_hdr_s,
 193                         { "Silence Indicator", "gsm_abis_tfp.silence_ind",
 194                           FT_BOOLEAN, 8, NULL, 0x40,
 195                           NULL, HFILL }
 196                 },
 197                 { &hf_tfp_hdr_m,
 198                         { "Marker bit", "gsm_abis_tfp.marker",
 199                           FT_BOOLEAN, 8, NULL, 0x20,
 200                           NULL, HFILL }
 201                 },
 202                 { &hf_tfp_hdr_frame_type,
 203                         { "Frame Type", "gsm_abis_tfp.frame_type",
 204                           FT_UINT8, BASE_DEC, VALS(tfp_frame_type_vals), 0x1e,
 205                           NULL, HFILL }
 206                 },
 207                 { &hf_tfp_amr_rate,
 208                         { "AMR Rate", "gsm_abis_tfp.amr.rate",
 209                           FT_UINT8, BASE_DEC, VALS(tfp_amr_len_rate_vals), 0,
 210                           NULL, HFILL }
 211                 },
 212         };
 213         static int *ett[] = {
 214                 &ett_tfp,
 215         };
 216
 217         /* assign our custom match functions */
 218         proto_abis_tfp = proto_register_protocol("GSM A-bis TFP", "Ericsson GSM A-bis TFP",
 219                                                  "gsm_abis_tfp");
 220
 221         proto_register_field_array(proto_abis_tfp, hf, array_length(hf));
 222         proto_register_subtree_array(ett, array_length(ett));
 223         tfp_handle = register_dissector("gsm_abis_tfp", dissect_abis_tfp, proto_abis_tfp);
 224 }
 225
 226 /* This function is called once at startup and every time the user hits
 227  * 'apply' in the preferences dialogue */
 228 void
 229 proto_reg_handoff_abis_tfp(void)
 230 {
 231         /* Those two SAPI values 10/11 are non-standard values, not specified by
 232          * ETSI/3GPP, just like this very same protocol. */
 233         dissector_add_uint("lapd.gsm.sapi", 10, tfp_handle);
 234         dissector_add_uint("lapd.gsm.sapi", 11, tfp_handle);
 235         sub_handles[SUB_DATA] = find_dissector("data");
 236 }
 237
 238 /*
 239  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 240  *
 241  * Local variables:
 242  * c-basic-offset: 8
 243  * tab-width: 8
 244  * indent-tabs-mode: t
 245  * End:
 246  *
 247  * vi: set shiftwidth=8 tabstop=8 noexpandtab:
 248  * :indentSize=8:tabSize=8:noTabs=false:
 249  */