epan/dissectors/packet-gmr1_dtap.c

   1 /* packet-gmr1_dtap.c
   2  *
   3  * Routines for GMR-1 DTAP dissection in wireshark.
   4  * Copyright (c) 2011 Sylvain Munaut <tnt@246tNt.com>
   5  *
   6  * References:
   7  *  [1] ETSI TS 101 376-4-8 V1.3.1 - GMR-1 04.008
   8  *  [2] ETSI TS 101 376-4-8 V2.2.1 - GMPRS-1 04.008
   9  *  [3] ETSI TS 101 376-4-8 V3.1.1 - GMR-1 3G 44.008
  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
  22 #include "packet-gmr1_common.h"
  23
  24 void proto_register_gmr1_dtap(void);
  25 void proto_reg_handoff_gmr1_dtap(void);
  26
  27 /* GMR-1 DTAP proto */
  28 static int proto_gmr1_dtap;
  29
  30 static int hf_gmr1_dtap_protocol_discriminator;
  31 static int hf_gmr1_dtap_message_elements;
  32
  33 /* GMR-1 DTAP sub tree */
  34 static int ett_gmr1_dtap;
  35 static int ett_gmr1_pd;
  36
  37 /* Handoffs */
  38 static dissector_handle_t gsm_dtap_handle;
  39 static dissector_handle_t dtap_handle;
  40
  41
  42 static int
  43 dissect_gmr1_dtap(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
  44 {
  45         uint32_t len, offset;
  46         gmr1_msg_func_t msg_func;
  47         const char *msg_str;
  48         int ett_tree;
  49         int hf_idx;
  50         proto_item *dtap_item = NULL/*, *pd_item = NULL*/;
  51         proto_tree *dtap_tree = NULL/*, *pd_tree = NULL*/;
  52         uint32_t oct[2];
  53         uint8_t pd;
  54
  55         /* Scan init */
  56         len = tvb_captured_length(tvb);
  57         offset = 0;
  58
  59         /* Protocol descriptor */
  60         oct[0] = tvb_get_uint8(tvb, offset++);
  61
  62         if ((oct[0] & GMR1_PD_EXT_MSK) == GMR1_PD_EXT_VAL)
  63                 pd = oct[0] & 0xff;
  64         else
  65                 pd = oct[0] & 0x0f;
  66
  67         /* HACK: Quick delegation hack to GSM */
  68         if (pd != GMR1_PD_RR) {
  69                 call_dissector(gsm_dtap_handle, tvb, pinfo, tree);
  70                 return tvb_captured_length(tvb);
  71         }
  72
  73         /* Fill up some info */
  74         col_append_str(pinfo->cinfo, COL_INFO, " (DTAP) ");
  75
  76         col_append_fstr(pinfo->cinfo, COL_INFO, "(%s) ",
  77                 val_to_str(pd, gmr1_pd_short_vals, "Unknown (%u)"));
  78
  79         /* Get message parameters */
  80         oct[1] = tvb_get_uint8(tvb, offset);
  81
  82         gmr1_get_msg_params((gmr1_pd_e)pd, oct[1], &msg_str, &ett_tree, &hf_idx, &msg_func);
  83
  84         /* Create protocol tree */
  85         if (msg_str == NULL)
  86         {
  87                 dtap_item = proto_tree_add_protocol_format(
  88                         tree, proto_gmr1_dtap, tvb, 0, len,
  89                         "GMR-1 DTAP - Message Type (0x%02x)", oct[1]);
  90                 dtap_tree = proto_item_add_subtree(dtap_item, ett_gmr1_dtap);
  91
  92                 col_append_fstr(pinfo->cinfo, COL_INFO, "Message Type (0x%02x) ", oct[1]);
  93         }
  94         else
  95         {
  96                 dtap_item = proto_tree_add_protocol_format(
  97                         tree, proto_gmr1_dtap, tvb, 0, -1,
  98                         "GMR-1 DTAP - %s", msg_str);
  99                 dtap_tree = proto_item_add_subtree(dtap_item, ett_gmr1_dtap);
 100
 101                 col_append_fstr(pinfo->cinfo, COL_INFO, "%s ", msg_str);
 102         }
 103
 104         /* Start over */
 105         offset = 0;
 106
 107         /* Protocol discriminator item */
 108         /*pd_item =*/ proto_tree_add_uint(
 109                 dtap_tree, hf_gmr1_dtap_protocol_discriminator, tvb, 1, 1, pd);
 110
 111         /*pd_tree = proto_item_add_subtree(pd_item, ett_gmr1_pd);*/
 112
 113                 /* Move on */
 114         offset++;
 115
 116         /* Message type - [1] 11.4 */
 117         proto_tree_add_uint_format(
 118                 dtap_tree, hf_idx, tvb, offset, 1, oct[1],
 119                 "Message Type: %s", msg_str ? msg_str : "(Unknown)"
 120         );
 121
 122         offset++;
 123
 124         /* Decode elements */
 125         if (msg_func) {
 126                 (*msg_func)(tvb, dtap_tree, pinfo, offset, len - offset);
 127         } else {
 128                 proto_tree_add_item(dtap_tree, hf_gmr1_dtap_message_elements, tvb, offset, len - offset, ENC_NA);
 129         }
 130
 131         /* Done ! */
 132         return tvb_captured_length(tvb);
 133 }
 134
 135
 136 void
 137 proto_register_gmr1_dtap(void)
 138 {
 139         static hf_register_info hf[] = {
 140                 { &hf_gmr1_dtap_protocol_discriminator,
 141                   { "Protocol Discriminator", "gmr1.dtap.protocol_discriminator",
 142                         FT_UINT8, BASE_DEC, VALS(gmr1_pd_vals), 0x0,
 143                         NULL, HFILL }
 144                 },
 145                 { &hf_gmr1_dtap_message_elements,
 146                   { "Message elements", "gmr1.dtap.message_elements",
 147                         FT_BYTES, BASE_NONE, NULL, 0x0,
 148                         NULL, HFILL }
 149                 },
 150         };
 151
 152         static int *ett[] = {
 153                 &ett_gmr1_dtap,
 154                 &ett_gmr1_pd,
 155         };
 156
 157         /* Setup protocol subtree array */
 158         proto_register_subtree_array(ett, array_length(ett));
 159
 160         /* Register the protocol name and field description */
 161         proto_gmr1_dtap = proto_register_protocol("GEO-Mobile Radio (1) DTAP", "GMR-1 DTAP", "gmr1.dtap");
 162         proto_register_field_array(proto_gmr1_dtap, hf, array_length(hf));
 163
 164         /* Register dissector */
 165         dtap_handle = register_dissector("gmr1_dtap", dissect_gmr1_dtap, proto_gmr1_dtap);
 166 }
 167
 168 void
 169 proto_reg_handoff_gmr1_dtap(void)
 170 {
 171         dissector_add_uint("lapsat.sapi", 0 , dtap_handle); /* LAPSat: CC/RR/MM */
 172         dissector_add_uint("lapsat.sapi", 3 , dtap_handle); /* LAPSat: SMS/SS */
 173
 174         gsm_dtap_handle = find_dissector_add_dependency("gsm_a_dtap", proto_gmr1_dtap);
 175 }
 176
 177 /*
 178  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 179  *
 180  * Local variables:
 181  * c-basic-offset: 8
 182  * tab-width: 8
 183  * indent-tabs-mode: t
 184  * End:
 185  *
 186  * vi: set shiftwidth=8 tabstop=8 noexpandtab:
 187  * :indentSize=8:tabSize=8:noTabs=false:
 188  */