Security queries are not implemented to spec

[jacobkeeler]

Bug Report

With the acceptance of SDL 0317, this library's implementation of security queries does not match the spec fully. Several issues exist with the current implementation such as:

1. When a security query is received from Core, its header is entirely ignored and the library assumes that it is a Send Handshake Data request. This causes issues if Core were to send another type of query, such as a Send Internal Error notification.

    // Tear off the binary header of the client protocol message to get at the actual TLS handshake
    // TODO: (Joel F.)[2016-02-15] Should check for errors
    NSData *clientHandshakeData = [clientHandshakeMessage.payload subdataWithRange:NSMakeRange(12, (clientHandshakeMessage.payload.length - 12))];

2. Hardcoded values are used when sending security queries for fields such as query type and query ID. Any predefined values should be properly added as constants.

    serverTLSPayload.functionID = 0x01; // TLS Handshake message
    serverTLSPayload.rpcType = 0x00;
    serverTLSPayload.correlationID = 0x00;

should be changed to something like

    serverTLSPayload.queryID = SDLQueryIDSendHandshakeData;
    serverTLSPayload.queryType = SDLQueryTypeResponse;
    serverTLSPayload.sequenceNumber = requestHeader.sequenceNumber;

3. Security queries are constructed using an RPC header, which has a slightly different format than a security query header. Security query headers should be implemented separate from RPC headers.

    // For a control service packet, we need a binary header with a function ID corresponding to what type of packet we're sending.
    SDLRPCPayload *serverTLSPayload = [[SDLRPCPayload alloc] init];
    ...
    NSData *binaryData = serverTLSPayload.data;

    return [SDLProtocolMessage messageWithHeader:serverMessageHeader andPayload:binaryData];

should be changed to something like

    // For a control service packet, we need a binary header with a function ID corresponding to what type of packet we're sending.
    SDLQueryPayload *serverTLSPayload = [[SDLQueryPayload alloc] init];
    ...
    NSData *binaryData = serverTLSPayload.data;

    return [SDLProtocolMessage messageWithHeader:serverMessageHeader andPayload:binaryData];

OS & Version Information

• iOS Version: N/A
• SDL iOS Version: master
• Testing Against: N/A

[theresalech]

See Core issue smartdevicelink/sdl_core#3755; the mobile libraries will need to account for this by accepting both the NOTIFICATION and REQUEST types for SendHandshakeData and just treating them as REQUEST type.