/// <summary>
/// Initializes broker for startup.
/// </summary>
/// <param name="platform">Platform implementations</param>
public Broker(AbstractPlatform platform)
{
Platform = platform;
_sha256 = new SHA256();
KeyPair = new KeyPair(".broker.key");
KeyPair.Load(Platform.FileSystem);
DsId = "broker-" + UrlBase64.Encode(_sha256.ComputeHash(KeyPair.EncodedPublicKey));
ClientHandler = new ClientHandler();
HttpHandler = new HttpHandler(this);
BrokerTree = new BrokerTree(this);
Handshake = new Handshake(this);
}
/// <summary>
/// Generates the shared secret for connecting to the broker.
/// </summary>
/// <returns>Shared secret</returns>
/// <param name="tempKey">Temporary key from server</param>
public byte[] GenerateSharedSecret(string tempKey)
{
var decoded = UrlBase64.Decode(tempKey);
var privateKey = ((ECPrivateKeyParameters)BcKeyPair.Private);
var param = privateKey.Parameters;
var point = param.Curve.DecodePoint(decoded);
var spec = new ECPublicKeyParameters(point, param);
point = spec.Q.Multiply(privateKey.D);
var bi = point.X.ToBigInteger();
return(Normalize(bi.ToByteArray()));
}
/// <summary>
/// Handles an incoming HTTP post request to /conn.
/// </summary>
/// <param name="postedData">JSON data that contains information about the connecting client.</param>
/// <param name="dsId">DSLink identifier for connecting client.</param>
/// <param name="token">Optional token for broker authentication.</param>
/// <returns>Constructed client object from provided data.</returns>
public Client HandleHandshake(string postedData, string dsId, string token = null)
{
var jsonIn = JObject.Parse(postedData);
var client = new Client();
client.Name = dsIdToName(dsId);
client.TempKey = new KeyPair();
if (string.IsNullOrEmpty(dsId))
{
throw new Exception("dsId must not be null or empty.");
}
else
{
if (!ValidateDsId(dsId))
{
throw new Exception("Invalid dsId was provided.");
}
client.DsId = dsId;
}
if (token != null)
{
client.Token = token;
}
if (jsonIn["isRequester"] == null && jsonIn["isResponder"] == null)
{
throw new Exception("Neither isRequester or isResponder was provided.");
}
if (jsonIn["publicKey"] == null || jsonIn["publicKey"].Type != JTokenType.String)
{
throw new Exception("publicKey was not provided or it is an invalid type.");
}
else
{
client.PublicKey = jsonIn["publicKey"].ToObject <string>();
}
if (jsonIn["isRequester"] != null && jsonIn["isRequester"].Type == JTokenType.Boolean)
{
client.Requester = jsonIn["isRequester"].ToObject <bool>();
}
else if (jsonIn["isRequester"] != null)
{
throw new Exception("isRequester was provided, but it is an invalid type.");
}
if (jsonIn["isResponder"] != null && jsonIn["isResponder"].Type == JTokenType.Boolean)
{
client.Responder = jsonIn["isResponder"].ToObject <bool>();
}
else if (jsonIn["isResponder"] != null)
{
throw new Exception("isResponder was provided, but it is an invalid type.");
}
if (jsonIn["version"] == null || jsonIn["version"].Type != JTokenType.String)
{
throw new Exception("version was not provided or invalid type.");
}
else
{
client.ReportingVersion = jsonIn["version"].ToObject <string>();
}
if (jsonIn["formats"] != null && jsonIn["formats"].Type != JTokenType.Array)
{
throw new Exception("formats was provided, but it is an invalid type.");
}
else if (jsonIn["formats"] == null)
{
// Server assumes client understands the JSON format if formats isn't provided.
client.Formats = new List <string>
{
"json"
};
}
else
{
var jarray = jsonIn["formats"].ToObject <JArray>();
var list = new List <string>();
foreach (JToken jtoken in jarray)
{
if (jtoken.Type != JTokenType.String)
{
throw new Exception("formats was provided as an array, but contained a value other than a string.");
}
list.Add(jtoken.ToObject <string>());
}
// If the DSLink SDK provides an empty formats list, let's assume they understand JSON.
// If they don't... I'm not sure what to tell them.
if (list.Count == 0)
{
client.Formats = new List <string>
{
"json"
};
}
client.Formats = list;
}
if (jsonIn["enableWebSocketCompression"] != null && jsonIn["enableWebSocketCompression"].Type == JTokenType.Boolean)
{
client.WebSocketCompression = jsonIn["enableWebSocketCompression"].ToObject <bool>();
}
else if (jsonIn["enableWebSocketCompression"] != null)
{
throw new Exception("enableWebSocketCompression was provided, but it is an invalid type.");
}
client.Name = _broker.BrokerTree.InitDSLink(client.Name, client.DsId);
client.HandshakeResponse["dsId"] = _broker.DsId;
client.HandshakeResponse["publicKey"] = UrlBase64.Encode(_broker.KeyPair.EncodedPublicKey);
client.HandshakeResponse["wsUri"] = "/ws";
client.HandshakeResponse["httpUri"] = "/http";
client.HandshakeResponse["tempKey"] = UrlBase64.Encode(client.TempKey.EncodedPublicKey);
client.HandshakeResponse["salt"] = Encoding.UTF8.GetString(GenerateSalt(), 0, 32);
if (client.Responder)
{
client.HandshakeResponse["path"] = "/downstream/" + client.Name;
}
client.HandshakeResponse["format"] = "json"; // TODO: use actual format
return(client);
}
