public void SetMasterKeys(IntPtr ssl, bool isClient)
{
var keyingMaterialHandle = default(GCHandle);
try
{
var keyingMaterial = new byte[2 * SRTP_MASTER_LEN];
keyingMaterialHandle = GCHandle.Alloc(keyingMaterial, GCHandleType.Pinned);
if (OpenSsl.SSL_export_keying_material(ssl, keyingMaterialHandle.AddrOfPinnedObject(),
2 * SRTP_MASTER_LEN,
Marshal.StringToHGlobalAnsi("EXTRACTOR-dtls_srtp"), 19,
IntPtr.Zero, 0, 0) != 1)
{
throw new Exception($"Cannot export keying material: {OpenSsl.GetLastError()}");
}
int offset = 0;
Array.Copy(keyingMaterial, offset, isClient ? _txKey : _rxKey, 0, SRTP_MASTER_KEY_LEN);
offset += SRTP_MASTER_KEY_LEN;
Array.Copy(keyingMaterial, offset, isClient ? _rxKey : _txKey, 0, SRTP_MASTER_KEY_LEN);
offset += SRTP_MASTER_KEY_LEN;
Array.Copy(keyingMaterial, offset, isClient ? _txSalt : _rxSalt, 0, SRTP_MASTER_SALT_LEN);
offset += SRTP_MASTER_SALT_LEN;
Array.Copy(keyingMaterial, offset, isClient ? _rxSalt : _txSalt, 0, SRTP_MASTER_SALT_LEN);
_rxRoc = 0;
_txRoc = 0;
}
finally
{
if (keyingMaterialHandle.IsAllocated)
{
keyingMaterialHandle.Free();
}
}
}
