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implement encodeMBT function to generate the PDU data header and data blocks for an AMBT;

Browse Source
2.0-maint
Bryan Biedenkapp 3 years ago
parent 263bab56ff
commit d68206591c
2 changed files with 85 additions and 6 deletions
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89
p25/lc/TSBK.cpp
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@ -186,7 +186,7 @@ bool TSBK::decodeMBT(const data::DataHeader dataHeader, const data::DataBlock* b
// get the second data block
uint8_t block2[P25_PDU_UNCONFIRMED_LENGTH_BYTES];
if (dataHeader.getBlocksToFollow() == 2U) {
if (dataHeader.getBlocksToFollow() >= 2U) {
uint32_t len = blocks[1U].getData(block2);
if (len != P25_PDU_UNCONFIRMED_LENGTH_BYTES) {
LogError(LOG_P25, "TSBK::decodeMBT(), failed to read PDU data block");
@ -304,11 +304,11 @@ bool TSBK::decodeMBT(const data::DataHeader dataHeader, const data::DataBlock* b
m_netId = (uint32_t)((tsbkValue >> 44) & 0xFFFFFU); // Network ID
m_sysId = (uint32_t)((tsbkValue >> 32) & 0xFFFU); // System ID
m_authStandalone = ((block2[2U] & 0xFFU) & 0x01U) == 0x01U; // Authentication Standalone Flag
m_authRand[4U] = (uint8_t)block1[5U] & 0xFFU; // Random Salt b0
m_authRand[3U] = (uint8_t)block1[6U] & 0xFFU; // Random Salt b0
m_authRand[2U] = (uint8_t)block1[7U] & 0xFFU; // Random Salt b0
m_authRand[1U] = (uint8_t)block1[8U] & 0xFFU; // Random Salt b0
m_authRand[0U] = (uint8_t)block1[9U] & 0xFFU; // Random Salt b0
m_authRand[4U] = (uint8_t)block1[5U] & 0xFFU; // Random Challenge b4
m_authRand[3U] = (uint8_t)block1[6U] & 0xFFU; // Random Challenge b3
m_authRand[2U] = (uint8_t)block1[7U] & 0xFFU; // Random Challenge b2
m_authRand[1U] = (uint8_t)block1[8U] & 0xFFU; // Random Challenge b1
m_authRand[0U] = (uint8_t)block1[9U] & 0xFFU; // Random Challenge b0
m_authRes[3U] = (uint8_t)block1[10U] & 0xFFU; // Result b3
m_authRes[2U] = (uint8_t)block1[11U] & 0xFFU; // Result b2
m_authRes[1U] = (uint8_t)block2[0U] & 0xFFU; // Result b1
@ -329,6 +329,83 @@ bool TSBK::decodeMBT(const data::DataHeader dataHeader, const data::DataBlock* b
return true;
}
/// <summary>
/// Encode a alternate trunking signalling block.
/// </summary>
/// <param name="dataHeader"></param>
/// <param name="blocks"></param>
void TSBK::encodeMBT(data::DataHeader& dataHeader, data::DataBlock* blocks)
{
assert(blocks != NULL);
uint8_t pduUserData[P25_PDU_UNCONFIRMED_LENGTH_BYTES * 2U];
::memset(pduUserData, 0x00U, P25_PDU_UNCONFIRMED_LENGTH_BYTES * 2U);
dataHeader.setFormat(PDU_FMT_UNCONFIRMED);
dataHeader.setMFId(m_mfId);
dataHeader.setAckNeeded(false);
dataHeader.setOutbound(true);
dataHeader.setSAP(PDU_SAP_TRUNK_CTRL);
dataHeader.setLLId(m_srcId);
dataHeader.setBlocksToFollow(1U);
dataHeader.setAMBTOpcode(m_lco);
// standard P25 reference opcodes
switch (m_lco) {
case TSBK_OSP_AUTH_DMD:
{
dataHeader.setBlocksToFollow(2U);
dataHeader.setAMBTField8((m_netId >> 12) & 0xFFU); // Network ID (b19-12)
dataHeader.setAMBTField9((m_netId >> 4) & 0xFFU); // Network ID (b11-b4)
/** Block 1 */
pduUserData[0U] = ((m_netId & 0x0FU) << 4) + ((m_sysId >> 8) & 0xFFU); // Network ID (b3-b0) + System ID (b11-b8)
pduUserData[1U] = (m_sysId & 0xFFU); // System ID (b7-b0)
__SET_UINT16(m_dstId, pduUserData, 2U); // Target Radio Address
pduUserData[5U] = m_authRS[9U]; // Random Salt b9
pduUserData[6U] = m_authRS[8U]; // Random Salt b8
pduUserData[7U] = m_authRS[7U]; // Random Salt b7
pduUserData[8U] = m_authRS[6U]; // Random Salt b6
pduUserData[9U] = m_authRS[5U]; // Random Salt b5
pduUserData[10U] = m_authRS[4U]; // Random Salt b4
pduUserData[11U] = m_authRS[3U]; // Random Salt b3
/** Block 2 */
pduUserData[12U] = m_authRS[2U]; // Random Salt b2
pduUserData[13U] = m_authRS[1U]; // Random Salt b1
pduUserData[14U] = m_authRS[0U]; // Random Salt b0
pduUserData[15U] = m_authRand[4U]; // Random Challenge b4
pduUserData[16U] = m_authRand[3U]; // Random Challenge b3
pduUserData[17U] = m_authRand[2U]; // Random Challenge b2
pduUserData[18U] = m_authRand[1U]; // Random Challenge b1
pduUserData[19U] = m_authRand[0U]; // Random Challenge b0
}
break;
default:
LogError(LOG_P25, "TSBK::encodeMBT(), unknown TSBK LCO value, mfId = $%02X, lco = $%02X", m_mfId, m_lco);
break;
}
// generate packet CRC-32 and set data blocks
if (dataHeader.getBlocksToFollow() > 1U) {
edac::CRC::addCRC32(pduUserData, P25_PDU_UNCONFIRMED_LENGTH_BYTES * dataHeader.getBlocksToFollow());
uint8_t offs = 0U;
for (uint8_t i = 0; i < dataHeader.getBlocksToFollow(); i++) {
blocks[i].setData(pduUserData + offs);
offs += P25_PDU_UNCONFIRMED_LENGTH_BYTES;
}
} else {
edac::CRC::addCRC32(pduUserData, P25_PDU_UNCONFIRMED_LENGTH_BYTES);
blocks[0U].setData(pduUserData);
}
}
/// <summary>
/// Decode a trunking signalling block.
/// </summary>

2
p25/lc/TSBK.h
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@ -83,6 +83,8 @@ namespace p25
/// <summary>Decode a alternate trunking signalling block.</summary>
bool decodeMBT(const data::DataHeader dataHeader, const data::DataBlock* blocks);
/// <summary>Encode a alternate trunking signalling block.</summary>
void encodeMBT(data::DataHeader& dataHeader, data::DataBlock* blocks);
/// <summary>Decode a trunking signalling block.</summary>
bool decode(const uint8_t* data, bool rawTSBK = false);

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