yojimbo_packet_processor.h

/*
    Yojimbo Client/Server Network Library.

    Copyright © 2016, The Network Protocol Company, Inc.

    Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

        1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

        2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer 
           in the documentation and/or other materials provided with the distribution.

        3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products derived 
           from this software without specific prior written permission.

    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, 
    INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 
    DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 
    SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 
    SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 
    WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
    USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

#ifndef YOJIMBO_PACKET_PROCESSOR_H
#define YOJIMBO_PACKET_PROCESSOR_H

#include "yojimbo_config.h"
#include "yojimbo_packet.h"

namespace yojimbo
{
    enum PacketProcessErrors
    {
        PACKET_PROCESSOR_ERROR_NONE,                        // everything is fine
        PACKET_PROCESSOR_ERROR_KEY_IS_NULL,                 // we needed an encryption/decryption key but it was passed in as NULL
        PACKET_PROCESSOR_ERROR_PACKET_TOO_SMALL,            // an encrypted packet was discarded because it was too short to possibly contain valid data
        PACKET_PROCESSOR_ERROR_WRITE_PACKET_FAILED,         // failed to write packet
        PACKET_PROCESSOR_ERROR_READ_PACKET_FAILED,          // failed to read packet
        PACKET_PROCESSOR_ERROR_ENCRYPT_FAILED,              // encrypt packet failed
        PACKET_PROCESSOR_ERROR_DECRYPT_FAILED,              // decrypt packet failed
    };

    class PacketProcessor
    {
    public:

        PacketProcessor( Allocator & allocator, uint32_t protocolId, int maxPacketSize );

        ~PacketProcessor();

        void SetContext( void * context );

        const uint8_t * WritePacket( Packet * packet, 
                                     uint64_t sequence, 
                                     int & packetBytes, 
                                     bool encrypt,
                                     const uint8_t * key,
                                     Allocator & streamAllocator,
                                     PacketFactory & packetFactory );

        Packet * ReadPacket( const uint8_t * packetData,  
                             uint64_t & sequence, 
                             int packetBytes, 
                             bool & encrypted,
                             const uint8_t * key, 
                             const uint8_t * encryptedPacketTypes, 
                             const uint8_t * unencryptedPacketTypes, 
                             Allocator & streamAllocator,
                             PacketFactory & packetFactory );

        int GetMaxPacketSize() const { return m_maxPacketSize; }

        int GetError() const { return m_error; }

    private:

        Allocator * m_allocator;

        uint32_t m_protocolId;

        int m_error;
        int m_maxPacketSize;
        int m_absoluteMaxPacketSize;
        
        uint8_t * m_packetBuffer;
        uint8_t * m_scratchBuffer;

        void * m_context;
    };
}

#endif // #ifndef YOJIMBO_PACKET_PROCESSOR