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 sub_handles[SUB_MAX];
  33
  34 /* initialize the protocol and registered fields */
  35 static int proto_abis_tfp = -1;
  36
  37 /* TFP header */
  38 static int hf_tfp_hdr_atsr = -1;
  39 static int hf_tfp_hdr_slot_rate = -1;
  40 static int hf_tfp_hdr_seq_nr = -1;
  41 static int hf_tfp_hdr_delay_info = -1;
  42 static int hf_tfp_hdr_p = -1;
  43 static int hf_tfp_hdr_s = -1;
  44 static int hf_tfp_hdr_m = -1;
  45 static int hf_tfp_hdr_frame_type = -1;
  46 static int hf_tfp_amr_rate = -1;
  47
  48 /* initialize the subtree pointers */
  49 static int ett_tfp = -1;
  50
  51 static const value_string tfp_slot_rate_vals[] = {
  52         { 0,    "Full Rate (16kbps)" },
  53         { 1,    "Sub-Channel 0 (8kbps)" },
  54         { 2,    "Sub-Channel 1 (8kbps)" },
  55         { 3,    "Reserved" },
  56         { 0, NULL }
  57 };
  58
  59 #define TFP_PACKED_NONE         0
  60 #define TFP_PACKED_SCHEME_1     1
  61
  62 static const value_string tfp_packed_vals[] = {
  63         { 0,    "Not Packed" },
  64         { 1,    "Packing Scheme 1" },
  65         { 0, NULL }
  66 };
  67
  68 static const value_string tfp_frame_type_vals[] = {
  69         /* 8k */
  70         { 0,    "TFP-AMR-IND" },
  71         { 1,    "TFP-SCCE-AMR-IND" },
  72         { 2,    "TFP-HR-IND" },
  73         /* 16k */
  74         { 0x80, "TFP-AMR-IND" },
  75         { 0x81, "TFP-SCCE-AMR-IND" },
  76         { 0x82, "TFP-FR-IND" },
  77         { 0x83, "TFP-EFR-IND" },
  78         { 0x84, "TFP-SCCE-EFR-IND" },
  79         { 0, NULL }
  80 };
  81
  82 static const value_string tfp_amr_len_rate_vals[] = {
  83         {  1, "SID_FIRST, ONSET, No speech/data" },
  84         {  5, "SID_UPDATE, SID_BAD" },
  85         { 12, "4.75k" },
  86         { 13, "5.15k" },
  87         { 15, "5.90k" },
  88         { 17, "6.70k" },
  89         { 19, "7.40k" },
  90         { 20, "7.95k" },
  91         { 26, "10.2k" },
  92         { 31, "12.2k" },
  93         { 0, NULL }
  94 };
  95
  96 static int
  97 dissect_abis_tfp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
  98 {
  99         proto_item *ti;
 100         proto_tree *tfp_tree;
 101         int offset = 0;
 102         guint32 slot_rate, frame_bits, atsr, seq_nr;
 103         guint8 ftype;
 104         tvbuff_t *next_tvb;
 105         gint len_remain;
 106
 107         col_set_str(pinfo->cinfo, COL_PROTOCOL, "TFP");
 108
 109         ti = proto_tree_add_item(tree, proto_abis_tfp, tvb, 0, -1, ENC_NA);
 110         tfp_tree = proto_item_add_subtree(ti, ett_tfp);
 111
 112         proto_tree_add_item_ret_uint(tfp_tree, hf_tfp_hdr_atsr, tvb, offset, 2, ENC_BIG_ENDIAN, &atsr);
 113         proto_tree_add_item_ret_uint(tfp_tree, hf_tfp_hdr_slot_rate, tvb, offset, 2, ENC_BIG_ENDIAN, &slot_rate);
 114         proto_tree_add_item_ret_uint(tfp_tree, hf_tfp_hdr_seq_nr, tvb, offset, 2, ENC_BIG_ENDIAN, &seq_nr);
 115         proto_tree_add_item(tfp_tree, hf_tfp_hdr_delay_info, tvb, offset+1, 2, ENC_BIG_ENDIAN);
 116         proto_tree_add_item(tfp_tree, hf_tfp_hdr_p, tvb, offset+1, 2, ENC_BIG_ENDIAN);
 117         proto_tree_add_item(tfp_tree, hf_tfp_hdr_s, tvb, offset+2, 1, ENC_NA);
 118         proto_tree_add_item(tfp_tree, hf_tfp_hdr_m, tvb, offset+2, 1, ENC_NA);
 119         /* Frame Type depends on Slot Rate */
 120         ftype = tvb_get_guint8(tvb, offset+2) & 0x1E;
 121         if (slot_rate == 0)
 122                 ftype |= 0x80;
 123         proto_tree_add_uint_format_value(tfp_tree, hf_tfp_hdr_frame_type, tvb, offset+2, 1, ftype, "%s",
 124                                          val_to_str(ftype, tfp_frame_type_vals, "Unknown (%u)"));
 125         offset += 2;
 126
 127         col_append_fstr(pinfo->cinfo, COL_INFO, "TS=%u, Seq=%u, %s, %s ", atsr, seq_nr,
 128                         val_to_str(slot_rate, tfp_slot_rate_vals, "Unknown (%u)"),
 129                         val_to_str(ftype, tfp_frame_type_vals, "Unknown (%u)"));
 130
 131         /* check for Tail bit == 1, iterate over further octests */
 132         while ((tvb_get_guint8(tvb, offset) & 0x01) == 0)
 133                 offset++;
 134         offset++;
 135
 136         switch (ftype & 0x7F) {
 137         case 0: /* TFP-AMR.ind */
 138                 len_remain = tvb_captured_length_remaining(tvb, offset);
 139                 proto_tree_add_uint(tfp_tree, hf_tfp_amr_rate, tvb, offset, 0, len_remain);
 140                 break;
 141         case 1: /* TFP-SCCE-AMR.ind */
 142                 break;
 143         case 2: /* TFP-HR.ind */
 144                 break;
 145         case 3: /* TFP-EFR.ind */
 146                 break;
 147         case 4: /* TFP-SCCE-EFR.ind */
 148                 break;
 149         }
 150
 151         /* FIXME: implement packed frame support */
 152         if (slot_rate == 0)
 153                 frame_bits = 320;
 154         else
 155                 frame_bits = 160;
 156         next_tvb = tvb_new_subset_length(tvb, offset, frame_bits/8);
 157         call_dissector(sub_handles[SUB_DATA], next_tvb, pinfo, tree);
 158
 159         return offset;
 160 }
 161
 162 void
 163 proto_register_abis_tfp(void)
 164 {
 165         static hf_register_info hf[] = {
 166                 { &hf_tfp_hdr_atsr,
 167                         { "Air Timeslot Resource", "gsm_abis_tfp.atsr",
 168                           FT_UINT16, BASE_DEC, NULL, 0xe000,
 169                           NULL, HFILL }
 170                 },
 171                 { &hf_tfp_hdr_slot_rate,
 172                         { "Slot Rate", "gsm_abis_tfp.slot_rate",
 173                           FT_UINT16, BASE_DEC, VALS(tfp_slot_rate_vals), 0x1800,
 174                           NULL, HFILL }
 175                 },
 176                 { &hf_tfp_hdr_seq_nr,
 177                         { "Sequence Number", "gsm_abis_tfp.seq_nr",
 178                           FT_UINT16, BASE_DEC, NULL, 0x07c0,
 179                           NULL, HFILL }
 180                 },
 181                 { &hf_tfp_hdr_delay_info,
 182                         { "Delay Information (ms)", "gsm_abis_tfp.delay_info",
 183                           FT_UINT16, BASE_DEC, NULL, 0x003e,
 184                           NULL, HFILL }
 185                 },
 186                 { &hf_tfp_hdr_p,
 187                         { "Packing Scheme", "gsm_abis_tfp.packing_scheme",
 188                           FT_UINT16, BASE_DEC, VALS(tfp_packed_vals), 0x0180,
 189                           NULL, HFILL }
 190                 },
 191                 { &hf_tfp_hdr_s,
 192                         { "Silence Indicator", "gsm_abis_tfp.silence_ind",
 193                           FT_BOOLEAN, 8, NULL, 0x40,
 194                           NULL, HFILL }
 195                 },
 196                 { &hf_tfp_hdr_m,
 197                         { "Marker bit", "gsm_abis_tfp.marker",
 198                           FT_BOOLEAN, 8, NULL, 0x20,
 199                           NULL, HFILL }
 200                 },
 201                 { &hf_tfp_hdr_frame_type,
 202                         { "Frame Type", "gsm_abis_tfp.frame_type",
 203                           FT_UINT8, BASE_DEC, VALS(tfp_frame_type_vals), 0x1e,
 204                           NULL, HFILL }
 205                 },
 206                 { &hf_tfp_amr_rate,
 207                         { "AMR Rate", "gsm_abis_tfp.amr.rate",
 208                           FT_UINT8, BASE_DEC, VALS(tfp_amr_len_rate_vals), 0,
 209                           NULL, HFILL }
 210                 },
 211         };
 212         static gint *ett[] = {
 213                 &ett_tfp,
 214         };
 215
 216         /* assign our custom match functions */
 217         proto_abis_tfp = proto_register_protocol("GSM A-bis TFP", "Ericsson GSM A-bis TFP",
 218                                                  "gsm_abis_tfp");
 219
 220         proto_register_field_array(proto_abis_tfp, hf, array_length(hf));
 221         proto_register_subtree_array(ett, array_length(ett));
 222         register_dissector("gsm_abis_tfp", dissect_abis_tfp, proto_abis_tfp);
 223 }
 224
 225 /* This function is called once at startup and every time the user hits
 226  * 'apply' in the preferences dialogue */
 227 void
 228 proto_reg_handoff_abis_tfp(void)
 229 {
 230         sub_handles[SUB_DATA] = find_dissector("data");
 231 }
 232
 233 /*
 234  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 235  *
 236  * Local variables:
 237  * c-basic-offset: 8
 238  * tab-width: 8
 239  * indent-tabs-mode: t
 240  * End:
 241  *
 242  * vi: set shiftwidth=8 tabstop=8 noexpandtab:
 243  * :indentSize=8:tabSize=8:noTabs=false:
 244  */