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wireshark/epan/dissectors/packet-dect-dlc.c

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/* packet-dect-dlc.c
*
* Dissector for the DECT (Digital Enhanced Cordless Telecommunications)
* DLC protocol layer as described in ETSI EN 300 175-4 V2.7.1 (2017-11)
*
* DLC is sometimes also called LAPC, which is a derivative of LAPDm (GSM),
* which is a derivative of LAPD (ISDN).
*
* Copyright 2018 by Harald Welte <laforge@gnumonks.org>
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#include "config.h"
#include <epan/packet.h>
#include <epan/prefs.h>
#include <epan/xdlc.h>
static int proto_dect_dlc = -1;
static gint hf_dlc_address = -1;
static gint hf_dlc_nlf = -1;
static gint hf_dlc_lln = -1;
static gint hf_dlc_sapi = -1;
static gint hf_dlc_cr = -1;
static int hf_dlc_control = -1;
static int hf_dlc_n_r = -1;
static int hf_dlc_n_s = -1;
static int hf_dlc_p = -1;
static int hf_dlc_f = -1;
static int hf_dlc_s_ftype = -1;
static int hf_dlc_u_modifier_cmd = -1;
static int hf_dlc_u_modifier_resp = -1;
static int hf_dlc_ftype_i = -1;
static int hf_dlc_ftype_s_u = -1;
static int hf_dlc_length = -1;
static int hf_dlc_el = -1;
static int hf_dlc_m = -1;
static int hf_dlc_len = -1;
static gint ett_dect_dlc = -1;
static gint ett_dect_dlc_address = -1;
static gint ett_dect_dlc_control = -1;
static gint ett_dect_dlc_length = -1;
static dissector_handle_t data_handle;
static dissector_table_t dlc_sapi_dissector_table;
static const xdlc_cf_items dlc_cf_items = {
&hf_dlc_n_r,
&hf_dlc_n_s,
&hf_dlc_p,
&hf_dlc_f,
&hf_dlc_s_ftype,
&hf_dlc_u_modifier_cmd,
&hf_dlc_u_modifier_resp,
&hf_dlc_ftype_i,
&hf_dlc_ftype_s_u
};
static const value_string dlc_sapi_vals[] = {
{ 0, "Connection oriented signalling" },
{ 3, "Connectionless signalling" },
{ 0, NULL }
};
static const value_string dlc_lln_vals[] = {
{ 0, "U0" },
{ 1, "A1" },
{ 2, "B2" },
{ 3, "B3" },
{ 4, "B4" },
{ 5, "B5" },
{ 6, "B6" },
{ 7, "unassigned" },
{ 0, NULL }
};
static const value_string dlc_m_vals[] = {
{ 0, "Last segment" },
{ 1, "More segments" },
{ 0, NULL }
};
static const value_string dlc_el_vals[] = {
{ 0, "More octets" },
{ 1, "Final octet" },
{ 0, NULL }
};
static int dissect_dect_dlc(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void _U_ *data)
{
proto_tree *dlc_tree, *addr_tree, *length_tree;
proto_item *dlc_ti, *addr_ti, *length_ti;
gboolean is_response = FALSE;
int available_length;
tvbuff_t *payload;
guint8 cr, sapi, length, len;
col_set_str(pinfo->cinfo, COL_PROTOCOL, "DECT-DLC");
cr = tvb_get_guint8(tvb, 0) & 0x02;
if (pinfo->p2p_dir == P2P_DIR_RECV)
is_response = cr ? FALSE : TRUE;
else if (pinfo->p2p_dir == P2P_DIR_SENT)
is_response = cr ? TRUE : FALSE;
dlc_ti = proto_tree_add_item(tree, proto_dect_dlc, tvb, 0, 3, ENC_NA);
dlc_tree = proto_item_add_subtree(dlc_ti, ett_dect_dlc);
addr_ti = proto_tree_add_item(dlc_tree, hf_dlc_address, tvb, 0, 1, ENC_NA);
addr_tree = proto_item_add_subtree(addr_ti, ett_dect_dlc_address);
sapi = (tvb_get_guint8(tvb, 0) & 0x0C) >> 2;
proto_tree_add_item(addr_tree, hf_dlc_nlf, tvb, 0, 1, ENC_NA);
proto_tree_add_item(addr_tree, hf_dlc_lln, tvb, 0, 1, ENC_NA);
proto_tree_add_item(addr_tree, hf_dlc_sapi, tvb, 0, 1, ENC_NA);
proto_tree_add_item(addr_tree, hf_dlc_cr, tvb, 0, 1, ENC_NA);
dissect_xdlc_control(tvb, 1, pinfo, dlc_tree, hf_dlc_control,
ett_dect_dlc_control, &dlc_cf_items, NULL, NULL, NULL,
is_response, FALSE, FALSE);
length_ti = proto_tree_add_item(dlc_tree, hf_dlc_length, tvb, 2, 1, ENC_NA);
length_tree = proto_item_add_subtree(length_ti, ett_dect_dlc_length);
length = tvb_get_guint8(tvb, 2);
proto_tree_add_uint(length_tree, hf_dlc_len, tvb, 2, 1, length);
proto_tree_add_uint(length_tree, hf_dlc_m, tvb, 2, 1, length);
proto_tree_add_uint(length_tree, hf_dlc_el, tvb, 2, 1, length);
len = length >> 2;
available_length = tvb_captured_length(tvb) - 3;
if (available_length > 0) {
payload = tvb_new_subset_length_caplen(tvb, 3, MIN(len, available_length), len);
/* FIXME: fragment reassembly like in packet-lapdm.c */
if (!dissector_try_uint(dlc_sapi_dissector_table, sapi, payload, pinfo, tree))
call_data_dissector(payload, pinfo, tree);
}
return tvb_captured_length(tvb);
}
void proto_register_dect_dlc(void)
{
static hf_register_info hf[] =
{
{ &hf_dlc_address,
{ "Address Field", "dect_dlc.address_field", FT_UINT8, BASE_HEX,
NULL, 0x0, NULL, HFILL
}
},
{ &hf_dlc_nlf,
{ "NLF", "dect_dlc.nlf", FT_UINT8, BASE_DEC,
NULL, 0x80, "New Link Flag", HFILL
}
},
{ &hf_dlc_lln,
{ "LLN", "dect_dlc.lln", FT_UINT8, BASE_DEC,
VALS(dlc_lln_vals), 0x70, "Logical Link Number", HFILL
}
},
{ &hf_dlc_sapi,
{ "SAPI", "dect_dlc.sapi", FT_UINT8, BASE_DEC,
VALS(dlc_sapi_vals), 0x0C, "Service Access Point Identifier", HFILL
}
},
{ &hf_dlc_cr,
{ "C/R", "dect_dlc.cr", FT_UINT8, BASE_DEC,
NULL, 0x02, "Command/Response field bit", HFILL
}
},
{ &hf_dlc_control,
{ "Control Field", "dect_dlc.control_field", FT_UINT8, BASE_HEX,
NULL, 0x0, NULL, HFILL
}
},
{ &hf_dlc_n_r,
{ "N(R)", "dect_dlc.control.n_r", FT_UINT8, BASE_DEC,
NULL, 0xE0, NULL, HFILL
}
},
{ &hf_dlc_n_s,
{ "N(S)", "dect_dlc.control.n_s", FT_UINT8, BASE_DEC,
NULL, 0x0E, NULL, HFILL
}
},
{ &hf_dlc_p,
{ "Poll", "dect_dlc.control.p", FT_BOOLEAN, 8,
TFS(&tfs_true_false), 0x10, NULL, HFILL
}
},
{ &hf_dlc_f,
{ "Final", "dect_dlc.control.f", FT_BOOLEAN, 8,
TFS(&tfs_true_false), 0x10, NULL, HFILL
}
},
{ &hf_dlc_s_ftype,
{ "Supervisory frame type", "dect_dlc.control.s_ftype", FT_UINT8, BASE_HEX,
VALS(stype_vals), XDLC_S_FTYPE_MASK, NULL, HFILL
}
},
{ &hf_dlc_u_modifier_cmd,
{ "Command", "dect_dlc.control.u_modifier_cmd", FT_UINT8, BASE_HEX,
VALS(modifier_vals_cmd), XDLC_U_MODIFIER_MASK, NULL, HFILL
}
},
{ &hf_dlc_u_modifier_resp,
{ "Response", "dect_dlc.control.u_modifier_resp", FT_UINT8, BASE_HEX,
VALS(modifier_vals_resp), XDLC_U_MODIFIER_MASK, NULL, HFILL
}
},
{ &hf_dlc_ftype_i,
{ "Frame type", "dect_dlc.control.ftype", FT_UINT8, BASE_HEX,
VALS(ftype_vals), XDLC_I_MASK, NULL, HFILL
}
},
{ &hf_dlc_ftype_s_u,
{ "Frame type", "dect_dlc.control.ftype", FT_UINT8, BASE_HEX,
VALS(ftype_vals), XDLC_S_U_MASK, NULL, HFILL
}
},
{ &hf_dlc_length,
{ "Length Field", "dect_dlc.length_field", FT_UINT8, BASE_HEX,
NULL, 0x0, NULL, HFILL
}
},
{ &hf_dlc_el,
{ "EL", "dect_dlc.el", FT_UINT8, BASE_DEC,
VALS(dlc_el_vals), 0x01, "Length indicator field extension bit", HFILL
}
},
{ &hf_dlc_m,
{ "M", "dect_dlc.m", FT_UINT8, BASE_DEC,
VALS(dlc_m_vals), 0x02, "More data bit", HFILL
}
},
{ &hf_dlc_len,
{ "Length", "dect_dlc.length", FT_UINT8, BASE_DEC,
NULL, 0xFC, "LEngth indicator", HFILL
}
},
};
static gint *ett[] = {
&ett_dect_dlc,
&ett_dect_dlc_address,
&ett_dect_dlc_control,
&ett_dect_dlc_length,
};
/* Register protocol */
proto_dect_dlc = proto_register_protocol("DECT DLC (LAPC)", "DECT-DLC", "dect_dlc");
proto_register_subtree_array(ett, array_length(ett));
proto_register_field_array(proto_dect_dlc, hf, array_length(hf));
register_dissector("dect_dlc", dissect_dect_dlc, proto_dect_dlc);
dlc_sapi_dissector_table = register_dissector_table("dect_dlc.sapi", "DECT DLC SAPI", proto_dect_dlc, FT_UINT8, BASE_DEC);
data_handle = find_dissector("data");
}
#if 0
void proto_reg_handoff_dect_aastra(void)
{
dissector_handle_t dlc_handle = create_dissector_handle(dissect_aamide_xdlc, proto_dect_dlc);
}
#endif
/*
* Editor modelines - http://www.wireshark.org/tools/modelines.html
*
* Local variables:
* c-basic-offset: 8
* tab-width: 8
* indent-tabs-mode: t
* End:
*
* vi: set shiftwidth=8 tabstop=8 noexpandtab:
* :indentSize=8:tabSize=8:noTabs=false:
*/
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