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199 lines
6.3 KiB
199 lines
6.3 KiB
/**
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* Digital Voice Modem - Host Software
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* GPLv2 Open Source. Use is subject to license terms.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* @package DVM / Host Software
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*
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*/
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/*
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* Copyright (C) 2020,2022 by Bryan Biedenkapp N2PLL
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include "Defines.h"
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#include "p25/P25Defines.h"
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#include "p25/data/DataRspHeader.h"
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#include "edac/CRC.h"
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#include "Utils.h"
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using namespace p25::data;
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using namespace p25;
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#include <cstdio>
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#include <cassert>
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#include <cstring>
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// ---------------------------------------------------------------------------
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// Public Class Members
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// ---------------------------------------------------------------------------
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/// <summary>
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/// Initializes a new instance of the DataRspHeader class.
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/// </summary>
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DataRspHeader::DataRspHeader() :
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m_outbound(true),
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m_rspClass(PDU_ACK_CLASS_NACK),
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m_rspType(PDU_ACK_TYPE_NACK_ILLEGAL),
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m_rspStatus(0U),
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m_mfId(P25_MFG_STANDARD),
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m_llId(0U),
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m_srcLlId(0U),
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m_extended(true),
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m_trellis(),
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m_blocksToFollow(0U),
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m_dataOctets(0U)
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{
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/* stub */
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}
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/// <summary>
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/// Finalizes a instance of the DataRspHeader class.
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/// </summary>
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DataRspHeader::~DataRspHeader()
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{
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/* stub */
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}
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/// <summary>
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/// Decodes P25 PDU data response header.
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/// </summary>
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/// <param name="data"></param>
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/// <returns>True, if PDU data response header was decoded, otherwise false.</returns>
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bool DataRspHeader::decode(const uint8_t* data)
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{
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assert(data != NULL);
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uint8_t header[P25_PDU_HEADER_LENGTH_BYTES];
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::memset(header, 0x00U, P25_PDU_HEADER_LENGTH_BYTES);
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// decode 1/2 rate Trellis & check CRC-CCITT 16
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bool valid = m_trellis.decode12(data, header);
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if (valid)
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valid = edac::CRC::checkCCITT162(header, P25_PDU_HEADER_LENGTH_BYTES);
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if (!valid) {
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return false;
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}
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#if DEBUG_P25_PDU_DATA
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Utils::dump(1U, "P25, DataRspHeader::decode(), PDU Response Header Data", data, P25_PDU_HEADER_LENGTH_BYTES);
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#endif
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m_outbound = (header[0U] & 0x20U) == 0x20U; // Inbound/Outbound
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m_rspClass = (header[1U] >> 6) & 0x03U; // Response Class
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m_rspType = (header[1U] >> 3) & 0x07U; // Response Type
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m_rspStatus = header[1U] & 0x07U; // Response Status
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m_mfId = header[2U]; // Mfg Id.
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m_llId = (header[3U] << 16) + (header[4U] << 8) + header[5U]; // Logical Link ID
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m_extended = (header[6U] & 0x80U) == 0x80U; // Extended Addressing
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m_blocksToFollow = header[6U] & 0x7FU; // Block Frames to Follow
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m_srcLlId = (header[7U] << 16) + (header[8U] << 8) + header[9U]; // Source Logical Link ID
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return true;
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}
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/// <summary>
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/// Encodes P25 PDU data response header.
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/// </summary>
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/// <param name="data"></param>
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void DataRspHeader::encode(uint8_t* data)
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{
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assert(data != NULL);
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uint8_t header[P25_PDU_HEADER_LENGTH_BYTES];
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::memset(header, 0x00U, P25_PDU_HEADER_LENGTH_BYTES);
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header[0U] = PDU_FMT_RSP;
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header[0U] = (m_outbound ? 0x20U : 0x00U) + // Inbound/Outbound
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(PDU_FMT_RSP & 0x1FU); // Packet Format
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header[1U] = ((m_rspClass & 0x03U) << 6) + // Response Class
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((m_rspType & 0x07U) << 3) + // Response Type
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((m_rspStatus & 0x07U)); // Response Status
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header[2U] = m_mfId; // Mfg Id.
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header[3U] = (m_llId >> 16) & 0xFFU; // Logical Link ID
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header[4U] = (m_llId >> 8) & 0xFFU;
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header[5U] = (m_llId >> 0) & 0xFFU;
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header[6U] = (m_extended ? 0x80U : 0x00U) + // Extended Addressing
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(m_blocksToFollow & 0x7FU); // Blocks Frames to Follow
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header[7U] = (m_srcLlId >> 16) & 0xFFU; // Source Logical Link ID
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header[8U] = (m_srcLlId >> 8) & 0xFFU;
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header[9U] = (m_srcLlId >> 0) & 0xFFU;
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// compute CRC-CCITT 16
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edac::CRC::addCCITT162(header, P25_PDU_HEADER_LENGTH_BYTES);
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#if DEBUG_P25_PDU_DATA
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Utils::dump(1U, "P25, DataRspHeader::encode(), PDU Response Header Data", header, P25_PDU_HEADER_LENGTH_BYTES);
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#endif
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// encode 1/2 rate Trellis
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m_trellis.encode12(header, data);
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}
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/// <summary>
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/// Helper to reset data values to defaults.
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/// </summary>
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void DataRspHeader::reset()
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{
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m_outbound = false;
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m_rspClass = PDU_ACK_CLASS_NACK;
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m_rspType = PDU_ACK_TYPE_NACK_ILLEGAL;
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m_rspStatus = 0U;
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m_mfId = P25_MFG_STANDARD;
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m_llId = 0U;
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m_srcLlId = 0U;
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m_extended = true;
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m_blocksToFollow = 0U;
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m_dataOctets = 0U;
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}
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/// <summary>Gets the total number of data octets.</summary>
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/// <returns></returns>
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uint32_t DataRspHeader::getDataOctets() const
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{
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return m_dataOctets;
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}
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/** Common Data */
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/// <summary>Sets the total number of blocks to follow this header.</summary>
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/// <param name="blocksToFollow"></param>
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void DataRspHeader::setBlocksToFollow(uint8_t blocksToFollow)
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{
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m_blocksToFollow = blocksToFollow;
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// recalculate count of data octets
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m_dataOctets = 16 * m_blocksToFollow - 4;
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}
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/// <summary>Gets the total number of blocks to follow this header.</summary>
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/// <returns></returns>
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uint8_t DataRspHeader::getBlocksToFollow() const
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{
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return m_blocksToFollow;
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}
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