forked from osmocom/wireshark
469 lines
14 KiB
C
469 lines
14 KiB
C
/* packet-dect-dlc.c
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*
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* Dissector for the DECT (Digital Enhanced Cordless Telecommunications)
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* DLC protocol layer as described in ETSI EN 300 175-4 V2.7.1 (2017-11)
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*
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* DLC is sometimes also called LAPC, which is a derivative of LAPDm (GSM),
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* which is a derivative of LAPD (ISDN).
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*
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* Copyright 2018 by Harald Welte <laforge@gnumonks.org>
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*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald@wireshark.org>
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* Copyright 1998 Gerald Combs
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*
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* SPDX-License-Identifier: GPL-2.0-or-later
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*/
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#include "config.h"
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#include <epan/conversation.h>
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#include <epan/packet.h>
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#include <epan/prefs.h>
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#include <epan/reassemble.h>
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#include <epan/xdlc.h>
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void proto_register_dect_dlc(void);
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static int proto_dect_dlc = -1;
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static gint hf_dect_dlc_address = -1;
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static gint hf_dect_dlc_nlf = -1;
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static gint hf_dect_dlc_lln = -1;
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static gint hf_dect_dlc_sapi = -1;
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static gint hf_dect_dlc_cr = -1;
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static int hf_dect_dlc_control = -1;
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static int hf_dect_dlc_n_r = -1;
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static int hf_dect_dlc_n_s = -1;
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static int hf_dect_dlc_p = -1;
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static int hf_dect_dlc_f = -1;
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static int hf_dect_dlc_s_ftype = -1;
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static int hf_dect_dlc_u_modifier_cmd = -1;
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static int hf_dect_dlc_u_modifier_resp = -1;
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static int hf_dect_dlc_ftype_i = -1;
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static int hf_dect_dlc_ftype_s_u = -1;
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static int hf_dect_dlc_length = -1;
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static int hf_dect_dlc_el = -1;
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static int hf_dect_dlc_m = -1;
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static int hf_dect_dlc_len = -1;
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static gint ett_dect_dlc = -1;
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static gint ett_dect_dlc_address = -1;
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static gint ett_dect_dlc_control = -1;
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static gint ett_dect_dlc_length = -1;
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static dissector_handle_t data_handle;
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static dissector_table_t dlc_sapi_dissector_table;
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static reassembly_table dect_dlc_reassembly_table;
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static int hf_dect_dlc_fragment_data = -1;
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static int hf_dect_dlc_fragment = -1;
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static int hf_dect_dlc_fragments = -1;
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static int hf_dect_dlc_fragment_overlap = -1;
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static int hf_dect_dlc_fragment_overlap_conflicts = -1;
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static int hf_dect_dlc_fragment_multiple_tails = -1;
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static int hf_dect_dlc_fragment_too_long_fragment = -1;
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static int hf_dect_dlc_fragment_error = -1;
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static int hf_dect_dlc_fragment_count = -1;
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static int hf_dect_dlc_reassembled_in = -1;
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static int hf_dect_dlc_reassembled_length = -1;
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static gint ett_dect_dlc_fragment = -1;
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static gint ett_dect_dlc_fragments = -1;
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static const fragment_items dect_dlc_frag_items = {
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/* Fragment subtrees */
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&ett_dect_dlc_fragment,
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&ett_dect_dlc_fragments,
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/* Fragment fields */
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&hf_dect_dlc_fragments,
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&hf_dect_dlc_fragment,
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&hf_dect_dlc_fragment_overlap,
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&hf_dect_dlc_fragment_overlap_conflicts,
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&hf_dect_dlc_fragment_multiple_tails,
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&hf_dect_dlc_fragment_too_long_fragment,
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&hf_dect_dlc_fragment_error,
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&hf_dect_dlc_fragment_count,
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/* Reassembled in field */
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&hf_dect_dlc_reassembled_in,
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/* Reassembled length field */
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&hf_dect_dlc_reassembled_length,
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/* Reassembled data field */
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NULL,
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/* Tag */
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"fragments"
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};
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static wmem_map_t *dect_dlc_last_n_s_map;
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#define DECT_DLC_M 0x02
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#define DECT_DLC_M_SHIFT 1
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static gboolean reassemble_dect_dlc = TRUE;
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static const xdlc_cf_items dect_dlc_cf_items = {
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&hf_dect_dlc_n_r,
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&hf_dect_dlc_n_s,
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&hf_dect_dlc_p,
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&hf_dect_dlc_f,
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&hf_dect_dlc_s_ftype,
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&hf_dect_dlc_u_modifier_cmd,
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&hf_dect_dlc_u_modifier_resp,
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&hf_dect_dlc_ftype_i,
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&hf_dect_dlc_ftype_s_u
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};
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static const value_string dect_dlc_sapi_vals[] = {
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{ 0, "Connection oriented signalling" },
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{ 3, "Connectionless signalling" },
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{ 0, NULL }
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};
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static const value_string dect_dlc_lln_vals[] = {
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{ 0, "U0" },
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{ 1, "A1" },
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{ 2, "B2" },
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{ 3, "B3" },
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{ 4, "B4" },
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{ 5, "B5" },
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{ 6, "B6" },
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{ 7, "unassigned" },
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{ 0, NULL }
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};
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static const value_string dect_dlc_m_vals[] = {
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{ 0, "Last segment" },
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{ 1, "More segments" },
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{ 0, NULL }
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};
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static const value_string dect_dlc_el_vals[] = {
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{ 0, "More octets" },
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{ 1, "Final octet" },
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{ 0, NULL }
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};
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static int dissect_dect_dlc(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void _U_ *data)
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{
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proto_tree *dlc_tree, *addr_tree, *length_tree;
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proto_item *dlc_ti, *addr_ti, *length_ti;
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gboolean is_response = FALSE;
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gboolean m;
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int available_length;
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int control;
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tvbuff_t *payload;
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guint8 cr, sapi, length, len, n_s;
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col_set_str(pinfo->cinfo, COL_PROTOCOL, "DECT-DLC");
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cr = tvb_get_guint8(tvb, 0) & 0x02;
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if (pinfo->p2p_dir == P2P_DIR_RECV)
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is_response = cr ? FALSE : TRUE;
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else if (pinfo->p2p_dir == P2P_DIR_SENT)
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is_response = cr ? TRUE : FALSE;
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dlc_ti = proto_tree_add_item(tree, proto_dect_dlc, tvb, 0, 3, ENC_NA);
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dlc_tree = proto_item_add_subtree(dlc_ti, ett_dect_dlc);
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addr_ti = proto_tree_add_item(dlc_tree, hf_dect_dlc_address, tvb, 0, 1, ENC_NA);
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addr_tree = proto_item_add_subtree(addr_ti, ett_dect_dlc_address);
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sapi = (tvb_get_guint8(tvb, 0) & 0x0C) >> 2;
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proto_tree_add_item(addr_tree, hf_dect_dlc_nlf, tvb, 0, 1, ENC_NA);
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proto_tree_add_item(addr_tree, hf_dect_dlc_lln, tvb, 0, 1, ENC_NA);
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proto_tree_add_item(addr_tree, hf_dect_dlc_sapi, tvb, 0, 1, ENC_NA);
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proto_tree_add_item(addr_tree, hf_dect_dlc_cr, tvb, 0, 1, ENC_NA);
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control = dissect_xdlc_control(tvb, 1, pinfo, dlc_tree, hf_dect_dlc_control,
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ett_dect_dlc_control, &dect_dlc_cf_items, NULL, NULL, NULL,
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is_response, FALSE, FALSE);
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n_s = (control & XDLC_N_S_MASK) >> XDLC_N_S_SHIFT;
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length_ti = proto_tree_add_item(dlc_tree, hf_dect_dlc_length, tvb, 2, 1, ENC_NA);
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length_tree = proto_item_add_subtree(length_ti, ett_dect_dlc_length);
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length = tvb_get_guint8(tvb, 2);
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proto_tree_add_uint(length_tree, hf_dect_dlc_len, tvb, 2, 1, length);
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proto_tree_add_uint(length_tree, hf_dect_dlc_m, tvb, 2, 1, length);
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proto_tree_add_uint(length_tree, hf_dect_dlc_el, tvb, 2, 1, length);
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len = length >> 2;
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available_length = tvb_captured_length(tvb) - 3;
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if (available_length > 0) {
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payload = tvb_new_subset_length_caplen(tvb, 3, MIN(len, available_length), len);
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/* Potentially segmented I frame */
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if( (control & XDLC_I_MASK) == XDLC_I && reassemble_dect_dlc && !pinfo->flags.in_error_pkt )
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{
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fragment_head *fd_m = NULL;
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tvbuff_t *reassembled = NULL;
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guint32 fragment_id;
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gboolean save_fragmented = pinfo->fragmented, add_frag;
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m = (length & DECT_DLC_M) >> DECT_DLC_M_SHIFT;
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pinfo->fragmented = m;
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fragment_id = (conversation_get_id_from_elements(pinfo, CONVERSATION_NONE, USE_LAST_ENDPOINT) << 3) | ( sapi << 1) | pinfo->p2p_dir;
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if (!PINFO_FD_VISITED(pinfo)) {
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/* Check if new N(S) is equal to previous N(S) (to avoid adding retransmissions in reassembly table)
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As GUINT_TO_POINTER macro does not allow to differentiate NULL from 0, use 1-8 range instead of 0-7 */
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guint *p_last_n_s = (guint*)wmem_map_lookup(dect_dlc_last_n_s_map, GUINT_TO_POINTER(fragment_id));
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if (GPOINTER_TO_UINT(p_last_n_s) == (guint)(n_s+1)) {
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add_frag = FALSE;
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} else {
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add_frag = TRUE;
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wmem_map_insert(dect_dlc_last_n_s_map, GUINT_TO_POINTER(fragment_id), GUINT_TO_POINTER(n_s+1));
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}
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} else {
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add_frag = TRUE;
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}
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if (add_frag) {
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/* This doesn't seem the best way of doing it as doesn't
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take N(S) into account, but N(S) isn't always 0 for
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the first fragment! */
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fd_m = fragment_add_seq_next (&dect_dlc_reassembly_table, payload, 0,
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pinfo,
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fragment_id, /* guint32 ID for fragments belonging together */
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NULL,
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/*n_s guint32 fragment sequence number */
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len, /* guint32 fragment length */
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m); /* More fragments? */
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reassembled = process_reassembled_data(payload, 0, pinfo,
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"Reassembled DLC", fd_m, &dect_dlc_frag_items,
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NULL, dlc_tree);
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/* Reassembled into this packet */
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if (fd_m && pinfo->num == fd_m->reassembled_in) {
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if (!dissector_try_uint(dlc_sapi_dissector_table, sapi,
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reassembled, pinfo, tree))
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call_data_dissector(reassembled, pinfo, tree);
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}
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else {
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col_append_str(pinfo->cinfo, COL_INFO, " (Fragment)");
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proto_tree_add_item(dlc_tree, hf_dect_dlc_fragment_data, payload, 0, -1, ENC_NA);
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}
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}
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/* Now reset fragmentation information in pinfo */
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pinfo->fragmented = save_fragmented;
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}
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else
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{
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if (!PINFO_FD_VISITED(pinfo) && ((control & XDLC_S_U_MASK) == XDLC_U) && ((control & XDLC_U_MODIFIER_MASK) == XDLC_SABM)) {
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/* SABM frame; reset the last N(S) to an invalid value */
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guint32 fragment_id = (conversation_get_id_from_elements(pinfo, CONVERSATION_GSMTAP, USE_LAST_ENDPOINT) << 3) | (sapi << 1) | pinfo->p2p_dir;
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wmem_map_insert(dect_dlc_last_n_s_map, GUINT_TO_POINTER(fragment_id), GUINT_TO_POINTER(0));
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}
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if (!dissector_try_uint(dlc_sapi_dissector_table, sapi, payload, pinfo, tree))
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call_data_dissector(payload, pinfo, tree);
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}
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}
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return tvb_captured_length(tvb);
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}
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void proto_register_dect_dlc(void)
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{
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static hf_register_info hf[] =
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{
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{ &hf_dect_dlc_address,
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{ "Address Field", "dect_dlc.address_field", FT_UINT8, BASE_HEX,
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NULL, 0x0, NULL, HFILL
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}
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},
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{ &hf_dect_dlc_nlf,
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{ "NLF", "dect_dlc.nlf", FT_UINT8, BASE_DEC,
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NULL, 0x80, "New Link Flag", HFILL
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}
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},
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{ &hf_dect_dlc_lln,
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{ "LLN", "dect_dlc.lln", FT_UINT8, BASE_DEC,
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VALS(dect_dlc_lln_vals), 0x70, "Logical Link Number", HFILL
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}
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},
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{ &hf_dect_dlc_sapi,
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{ "SAPI", "dect_dlc.sapi", FT_UINT8, BASE_DEC,
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VALS(dect_dlc_sapi_vals), 0x0C, "Service Access Point Identifier", HFILL
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}
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},
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{ &hf_dect_dlc_cr,
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{ "C/R", "dect_dlc.cr", FT_UINT8, BASE_DEC,
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NULL, 0x02, "Command/Response field bit", HFILL
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}
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},
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{ &hf_dect_dlc_control,
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{ "Control Field", "dect_dlc.control_field", FT_UINT8, BASE_HEX,
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NULL, 0x0, NULL, HFILL
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}
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},
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{ &hf_dect_dlc_n_r,
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{ "N(R)", "dect_dlc.control.n_r", FT_UINT8, BASE_DEC,
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NULL, 0xE0, NULL, HFILL
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}
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},
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{ &hf_dect_dlc_n_s,
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{ "N(S)", "dect_dlc.control.n_s", FT_UINT8, BASE_DEC,
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NULL, 0x0E, NULL, HFILL
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}
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},
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{ &hf_dect_dlc_p,
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{ "Poll", "dect_dlc.control.p", FT_BOOLEAN, 8,
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TFS(&tfs_true_false), 0x10, NULL, HFILL
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}
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},
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{ &hf_dect_dlc_f,
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{ "Final", "dect_dlc.control.f", FT_BOOLEAN, 8,
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TFS(&tfs_true_false), 0x10, NULL, HFILL
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}
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},
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{ &hf_dect_dlc_s_ftype,
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{ "Supervisory frame type", "dect_dlc.control.s_ftype", FT_UINT8, BASE_HEX,
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VALS(stype_vals), XDLC_S_FTYPE_MASK, NULL, HFILL
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}
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},
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{ &hf_dect_dlc_u_modifier_cmd,
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{ "Command", "dect_dlc.control.u_modifier_cmd", FT_UINT8, BASE_HEX,
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VALS(modifier_vals_cmd), XDLC_U_MODIFIER_MASK, NULL, HFILL
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}
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},
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{ &hf_dect_dlc_u_modifier_resp,
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{ "Response", "dect_dlc.control.u_modifier_resp", FT_UINT8, BASE_HEX,
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VALS(modifier_vals_resp), XDLC_U_MODIFIER_MASK, NULL, HFILL
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}
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},
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{ &hf_dect_dlc_ftype_i,
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{ "Frame type", "dect_dlc.control.ftype", FT_UINT8, BASE_HEX,
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VALS(ftype_vals), XDLC_I_MASK, NULL, HFILL
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}
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},
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{ &hf_dect_dlc_ftype_s_u,
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{ "Frame type", "dect_dlc.control.ftype", FT_UINT8, BASE_HEX,
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VALS(ftype_vals), XDLC_S_U_MASK, NULL, HFILL
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}
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},
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{ &hf_dect_dlc_length,
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{ "Length Field", "dect_dlc.length_field", FT_UINT8, BASE_HEX,
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NULL, 0x0, NULL, HFILL
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}
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},
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{ &hf_dect_dlc_el,
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{ "EL", "dect_dlc.el", FT_UINT8, BASE_DEC,
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VALS(dect_dlc_el_vals), 0x01, "Length indicator field extension bit", HFILL
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}
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},
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{ &hf_dect_dlc_m,
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{ "M", "dect_dlc.m", FT_UINT8, BASE_DEC,
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VALS(dect_dlc_m_vals), 0x02, "More data bit", HFILL
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}
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},
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{ &hf_dect_dlc_len,
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{ "Length", "dect_dlc.length", FT_UINT8, BASE_DEC,
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NULL, 0xFC, "Length indicator", HFILL
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}
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},
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/* Fragment reassembly */
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{ &hf_dect_dlc_fragment_data,
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{ "Fragment Data", "dect_dlc.fragment_data", FT_NONE, BASE_NONE,
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NULL, 0x00, NULL, HFILL
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}
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},
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{ &hf_dect_dlc_fragments,
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{ "Message fragments", "dect_dlc.fragments",
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FT_NONE, BASE_NONE, NULL, 0x00, NULL, HFILL
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}
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},
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{ &hf_dect_dlc_fragment,
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{ "Message fragment", "dect_dlc.fragment",
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FT_FRAMENUM, BASE_NONE, NULL, 0x00, NULL, HFILL
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}
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},
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{ &hf_dect_dlc_fragment_overlap,
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{ "Message fragment overlap", "dect_dlc.fragment.overlap",
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FT_BOOLEAN, 0, NULL, 0x00, NULL, HFILL
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}
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},
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{ &hf_dect_dlc_fragment_overlap_conflicts,
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{ "Message fragment overlapping with conflicting data",
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"dect_dlc.fragment.overlap.conflicts",
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FT_BOOLEAN, 0, NULL, 0x00, NULL, HFILL
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}
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},
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{ &hf_dect_dlc_fragment_multiple_tails,
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{ "Message has multiple tail fragments",
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"dect_dlc.fragment.multiple_tails",
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FT_BOOLEAN, 0, NULL, 0x00, NULL, HFILL
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}
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},
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{ &hf_dect_dlc_fragment_too_long_fragment,
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{ "Message fragment too long", "dect_dlc.fragment.too_long_fragment",
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FT_BOOLEAN, 0, NULL, 0x00, NULL, HFILL
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}
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|
},
|
|
{ &hf_dect_dlc_fragment_error,
|
|
{ "Message defragmentation error", "dect_dlc.fragment.error",
|
|
FT_FRAMENUM, BASE_NONE, NULL, 0x00, NULL, HFILL
|
|
}
|
|
},
|
|
{ &hf_dect_dlc_fragment_count,
|
|
{ "Message fragment count", "dect_dlc.fragment.count",
|
|
FT_UINT32, BASE_DEC, NULL, 0x00, NULL, HFILL
|
|
}
|
|
},
|
|
{ &hf_dect_dlc_reassembled_in,
|
|
{ "Reassembled in", "dect_dlc.reassembled.in",
|
|
FT_FRAMENUM, BASE_NONE, NULL, 0x00, NULL, HFILL
|
|
}
|
|
},
|
|
{ &hf_dect_dlc_reassembled_length,
|
|
{ "Reassembled length", "dect_dlc.reassembled.length",
|
|
FT_UINT32, BASE_DEC, NULL, 0x00, NULL, HFILL
|
|
}
|
|
},
|
|
};
|
|
|
|
static gint *ett[] = {
|
|
&ett_dect_dlc,
|
|
&ett_dect_dlc_address,
|
|
&ett_dect_dlc_control,
|
|
&ett_dect_dlc_length,
|
|
&ett_dect_dlc_fragment,
|
|
&ett_dect_dlc_fragments,
|
|
};
|
|
|
|
/* 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");
|
|
|
|
reassembly_table_register(&dect_dlc_reassembly_table,
|
|
&addresses_reassembly_table_functions);
|
|
dect_dlc_last_n_s_map = wmem_map_new_autoreset(wmem_epan_scope(), wmem_file_scope(), g_direct_hash, g_direct_equal);
|
|
}
|
|
|
|
/*
|
|
* 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:
|
|
*/
|