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Add EXT_FNCT TSBK; refactor P25Crypto to use a single keystream buffer and KeyInfo

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4.32j_maint
firealarmss 11 months ago
parent 1e1f6379f6
commit 2188db063a
3 changed files with 130 additions and 21 deletions
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44
P25/P25Crypto.cs
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@ -28,15 +28,13 @@ namespace fnecore.P25
private byte algId;
private ushort keyId;
private byte[] keystream;
private byte[] messageIndicator = new byte[9];
private Dictionary<ushort, KeyInfo> keys = new Dictionary<ushort, KeyInfo>();
private byte[] aesKeystream = new byte[240]; // AES buffer
private byte[] adpKeystream = new byte[469]; // ADP buffer
private int ksPosition;
private KeyInfo currentKey;
/*
** Class
*/
@ -91,7 +89,7 @@ namespace fnecore.P25
/// </summary>
public void Reset()
{
keys.Clear();
currentKey = null;
}
/// <summary>
@ -100,12 +98,14 @@ namespace fnecore.P25
/// <param name="keyid"></param>
/// <param name="algid"></param>
/// <param name="key"></param>
public void AddKey(ushort keyid, byte algid, byte[] key)
public void SetKey(ushort keyid, byte algid, byte[] key)
{
if (keyid == 0 || algid == 0x80)
return;
keys[keyid] = new KeyInfo(algid, key);
this.keyId = keyid;
this.algId = algid;
this.currentKey = new KeyInfo(algid, key);
}
/// <summary>
@ -113,9 +113,9 @@ namespace fnecore.P25
/// </summary>
/// <param name="keyId"></param>
/// <returns></returns>
public bool HasKey(ushort keyId)
public bool HasKey()
{
return keys.ContainsKey(keyId);
return currentKey != null;
}
/// <summary>
@ -133,18 +133,20 @@ namespace fnecore.P25
Array.Copy(MI, this.messageIndicator, Math.Min(MI.Length, this.messageIndicator.Length));
if (!keys.ContainsKey(keyid))
if (currentKey == null)
return false;
this.ksPosition = 0;
if (algid == P25Defines.P25_ALGO_AES)
{
keystream = new byte[240];
GenerateAESKeystream();
return true;
}
else if (algid == P25Defines.P25_ALGO_ARC4)
{
keystream = new byte[469];
GenerateARC4Keystream();
return true;
}
@ -160,7 +162,7 @@ namespace fnecore.P25
/// <returns></returns>
public bool Process(byte[] imbe, P25DUID duid)
{
if (!keys.ContainsKey(keyId))
if (currentKey == null)
return false;
return algId switch
@ -193,10 +195,10 @@ namespace fnecore.P25
byte[] permutation = new byte[256];
byte[] key = new byte[256];
if (!keys.ContainsKey(keyId))
if (currentKey == null)
return;
byte[] keyData = keys[keyId].Key;
byte[] keyData = currentKey.Key;
int keySize = keyData.Length;
int padding = Math.Max(5 - keySize, 0);
@ -239,7 +241,7 @@ namespace fnecore.P25
Swap(permutation, i, j);
// transform byte
adpKeystream[k] = permutation[(permutation[i] + permutation[j]) & 0xFF];
keystream[k] = permutation[(permutation[i] + permutation[j]) & 0xFF];
}
}
@ -248,10 +250,10 @@ namespace fnecore.P25
/// </summary>
private void GenerateAESKeystream()
{
if (!keys.ContainsKey(keyId))
if (currentKey == null)
return;
byte[] key = keys[keyId].Key;
byte[] key = currentKey.Key;
byte[] iv = ExpandMIToIV(messageIndicator);
using (var aes = Aes.Create())
@ -268,10 +270,10 @@ namespace fnecore.P25
Array.Copy(iv, input, 16);
byte[] output = new byte[16];
for (int i = 0; i < aesKeystream.Length / 16; i++)
for (int i = 0; i < keystream.Length / 16; i++)
{
encryptor.TransformBlock(input, 0, 16, output, 0);
Buffer.BlockCopy(output, 0, aesKeystream, i * 16, 16);
Buffer.BlockCopy(output, 0, keystream, i * 16, 16);
Array.Copy(output, input, 16);
}
}
@ -294,7 +296,7 @@ namespace fnecore.P25
ksPosition = (ksPosition + 1) % 9;
for (int j = 0; j < IMBE_BUF_LEN; ++j)
imbe[j] ^= aesKeystream[j + offset];
imbe[j] ^= keystream[j + offset];
return true;
}
@ -318,7 +320,7 @@ namespace fnecore.P25
ksPosition = (ksPosition + 1) % 9;
for (int j = 0; j < IMBE_BUF_LEN; ++j)
imbe[j] ^= adpKeystream[j + offset];
imbe[j] ^= keystream[j + offset];
return true;
}

23
P25/P25Defines.cs
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@ -120,6 +120,29 @@ namespace fnecore.P25
TDULC = 0x0F
} // public enum P25DUID : byte
/// <summary>
/// Extended Function types for EXT_FNCT TSBK
/// </summary>
public enum ExtendedFunction : ushort
{
CHECK = 0x0000, // Radio Check
UNINHIBIT = 0x007E, // Radio Uninhibit
INHIBIT = 0x007F, // Radio Inhibit
CHECK_ACK = 0x0080, // Radio Check Ack
UNINHIBIT_ACK = 0x00FE, // Radio Uninhibit Ack
INHIBIT_ACK = 0x00FF, // Radio Inhibit Ack
DYN_REGRP_REQ = 0x0200, // MFID $90 (Motorola) Dynamic Regroup IR
DYN_REGRP_CANCEL = 0x0201, // MFID $90 (Motorola) Dynamic Regroup IR Cancellation
DYN_REGRP_LOCK = 0x0202, // MFID $90 (Motorola) Lock Selector
DYN_REGRP_UNLOCK = 0x0203, // MFID $90 (Motorola) Unlock Selector
DYN_REGRP_REQ_ACK = 0x0280, // MFID $90 (Motorola) Dynamic Regroup IR Ack
DYN_REGRP_CANCEL_ACK = 0x0281, // MFID $90 (Motorola) Dynamic Regroup IR Cancellation Ack
DYN_REGRP_LOCK_ACK = 0x0282, // MFID $90 (Motorola) Lock Selector Ack
DYN_REGRP_UNLOCK_ACK = 0x0283 // MFID $90 (Motorola) Unlock Selector Ack
} // public enum ExtendedFunction : ushort
/// <summary>
/// P25 Constants
/// </summary>

84
P25/lc/tsbk/IOSP_EXT_FNCT.cs
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@ -0,0 +1,84 @@
// SPDX-License-Identifier: AGPL-3.0-only
/**
* Digital Voice Modem - Fixed Network Equipment Core Library
* AGPLv3 Open Source. Use is subject to license terms.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* @package DVM / Fixed Network Equipment Core Library
* @license AGPLv3 License (https://opensource.org/licenses/AGPL-3.0)
*
* Copyright (C) 2025 Caleb, K4PHP
*
*/
namespace fnecore.P25.LC.TSBK
{
/// <summary>
/// IOSP_EXT_FNCT TSBK
/// </summary>
public class IOSP_EXT_FNCT : TSBKBase
{
public ushort ExtendedFunction { get; set; }
public uint SrcId { get; set; }
public uint DstId { get; set; }
/// <summary>
/// Creates an instance of <see cref="IOSP_EXT_FNCT"/>
/// </summary>
/// <param name="extendedFunction"></param>
/// <param name="srcId"></param>
/// <param name="dstId"></param>
public IOSP_EXT_FNCT(ushort extendedFunction = 0, uint srcId = 0, uint dstId = 0)
{
ExtendedFunction = extendedFunction;
SrcId = srcId;
DstId = dstId;
Lco = P25Defines.TSBK_IOSP_EXT_FNCT;
}
/// <summary>
/// Decode EXT_FNCT TSBK
/// </summary>
/// <param name="data"></param>
/// <param name="rawTSBK"></param>
/// <returns></returns>
public bool Decode(byte[] data, bool rawTSBK)
{
byte[] tsbk = new byte[P25Defines.P25_TSBK_LENGTH_BYTES];
FneUtils.Memset(tsbk, 0x00, tsbk.Length);
bool ret = base.Decode(data, ref tsbk, rawTSBK);
if (!ret)
return false;
ulong tsbkValue = FneUtils.ToUInt64(tsbk, 0);
ExtendedFunction = (ushort)((tsbkValue >> 48) & 0xFFFF); // Extended Function
SrcId = (uint)((tsbkValue >> 24) & 0xFFFFFF); // Argument
DstId = (uint)(tsbkValue & 0xFFFFFF); // Target Radio Address
return true;
}
/// <summary>
/// Encode EXT_FNCT TSBK
/// </summary>
/// <param name="data"></param>
/// <param name="payload"></param>
/// <param name="rawTSBK"></param>
/// <param name="noTrellis"></param>
public override void Encode(ref byte[] data, ref byte[] payload, bool rawTSBK, bool noTrellis)
{
ulong tsbkValue = 0;
tsbkValue = (tsbkValue << 16) + ExtendedFunction; // Extended Function
tsbkValue = (tsbkValue << 24) + SrcId; // Argument
tsbkValue = (tsbkValue << 24) + DstId; // Target Radio Address
FneUtils.Memset(payload, 0x00, payload.Length);
FneUtils.WriteBytes(tsbkValue, ref payload, 0);
base.Encode(ref data, ref payload, rawTSBK, noTrellis);
}
} // public class IOSP_EXT_FNCT
} // namespace fnecore.P25.LC.TSBK
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