/home/jander/temp/etherdune/UDPSocket.cpp

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// EtherDune UDP implementation as a NetworkService
// Author: Javier Peletier <jm@friendev.com>
// Summary: Implements the UDP protocol
//
// Copyright (c) 2015 All Rights Reserved, http://friendev.com
//
// This source is subject to the GPLv2 license.
// Please see the License.txt file for more information.
// All other rights reserved.
//
// THIS CODE AND INFORMATION ARE PROVIDED "AS IS" WITHOUT WARRANTY OF ANY 
// KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
// PARTICULAR PURPOSE.

#include "UDPSocket.h"
#include "Checksum.h"

#define AC_LOGLEVEL 2
#include <ACLog.h>
ACROSS_MODULE("UDPSocket");

void UDPSocket::onReceive(uint16_t len) {  }


UDPSocket::UDPSocket() :sending(false)
{
#if _DEBUG
    localPort.l = random(255);
#else
    localPort.l = srcPort_L_count++;
#endif
    localPort.h = UDP_SRC_PORT_H;
}

bool UDPSocket::send()
{
    if (sending)
        return false;

    sending = true;
    UDPSocket::tick();

    return true;
}


void UDPSocket::prepareUDPPacket(uint16_t dataLength, uint16_t dataChecksum)
{
    packet.ip.totalLength=dataLength + sizeof(IPHeader) + sizeof(UDPHeader);
    packet.ip.protocol = IP_PROTO_UDP;
    prepareIPPacket();
    packet.udp.sourcePort = localPort;
    packet.udp.destinationPort = remotePort;

    packet.udp.dataLength = dataLength + sizeof(UDPHeader);
    packet.udp.checksum.zero();

    packet.udp.checksum.rawValue = calcUDPChecksum(dataLength, dataChecksum);

}

bool UDPSocket::sendPacket()
{
    uint16_t dataChecksum = 0;
    uint16_t dataLength;

    dataLength = buffer.fillTxBuffer(sizeof(EthernetHeader) + sizeof(IPHeader) + sizeof(UDPHeader),/*out*/ dataChecksum);

    prepareUDPPacket(dataLength, dataChecksum);

    if (sendIPPacket(sizeof(IPHeader) + sizeof(UDPHeader)))
    {
        buffer.flush();
        return false;
    }
    else
        return true;
}

void UDPSocket::tick()
{
    if (sending)
        sending = sendPacket();

}

bool UDPSocket::onPacketReceived()
{
    if (!(
        packet.eth.etherType == ETHTYPE_IP &&
        packet.ip.protocol == IP_PROTO_UDP &&
        localPort.rawValue == packet.udp.destinationPort.rawValue))
    {
        return false;
    }

    loadAll();

#if ENABLE_UDPTCP_RX_CHECKSUM

    if (!verifyUDPTCPChecksum())
    {
        ACWARN("UDP checksum error");
        return true;// drop packet, UDP checksum error
    }

#endif

    onReceive(packet.udp.dataLength - sizeof(UDPHeader));
    return true;
}