UdpOutDevice Class Reference

UdpOutDevice is a pseudo interface that allows communcation with the real world through the UdpOutScheduler. More...

#include <UdpOutDevice.h>

Inheritance diagram for UdpOutDevice:

Protected Member Functions
virtual char *	encapsulate (cPacket *msg, unsigned int *length, sockaddr **addr, socklen_t *addrlen)
	Converts an IP datagram to a data block for sending it to the (realworld) network.
virtual cPacket *	decapsulate (char *buf, uint32_t length, sockaddr *addr, socklen_t addrlen)
	Parses data received from the (realworld) network and converts it into a cMessage.
Protected Member Functions inherited from RealworldDevice
InterfaceEntry *	registerInterface ()
	Register the interface in the interface table of the parent.
Protected Member Functions inherited from RealworldConnector
virtual void	transmitToNetwork (cPacket *msg)
	Send a message to the (realworld) network.
virtual void	updateDisplayString ()
virtual bool	isApp ()
	If the Connector connects to an application, this method has to be overwritten to return "true".

Additional Inherited Members
Public Member Functions inherited from RealworldDevice
virtual int	numInitStages () const
virtual void	initialize (int stage)
	Initialization of the module.
Protected Attributes inherited from RealworldDevice
InterfaceEntry *	interfaceEntry

Detailed Description

UdpOutDevice is a pseudo interface that allows communcation with the real world through the UdpOutScheduler.

WARNING: This does ONLY work with the combination IPv4|UDP|OverlayMessage

Definition at line 36 of file UdpOutDevice.h.

Member Function Documentation

cPacket * UdpOutDevice::decapsulate ( char *  buf, uint32_t  length, sockaddr *  addr, socklen_t  addrlen  )

protectedvirtual

Parses data received from the (realworld) network and converts it into a cMessage.

Parameters

buf	A pointer to the data to be parsed
length	The lenght of the buffer in bytes
addr	The destination address
addrlen	The length of the address

Returns

The parsed message

Implements RealworldConnector.

Definition at line 109 of file UdpOutDevice.cc.

{
    if (!addr) {
        opp_error("UdpOutDevice::decapsulate called without providing "
                  "sockaddr (addr = NULL)");
    }

    if (addrlen != sizeof(sockaddr_in) ) {
        opp_error("UdpOutDevice::decapsulate called with wrong sockaddr length. "
                  "Only IPv4 is supported at the moment!");
    }
    sockaddr_in* addrbuf = (sockaddr_in*) addr;

    IPDatagram* IP = new IPDatagram;
    UDPPacket* UDP = new UDPPacket;
    cPacket* payload = 0;

    // Parse Payload
    payload = parser->decapsulatePayload(buf, length);

    if (!payload) {
        EV << "[UdpOutDevice::decapsulate()]\n"
           << "    Parsing of payload failed, dropping packet"
           << endl;
        goto parse_error;
    }

    // Create IP + UDP header
    IP->setSrcAddress(IPAddress(ntohl(addrbuf->sin_addr.s_addr)));
    IP->setDestAddress(IPAddressResolver().addressOf(getParentModule()).get4());
    IP->setTransportProtocol(IPPROTO_UDP);
    IP->setTimeToLive(42); // Does not matter, packet ends here
    IP->setIdentification(42); // Faked: There is no way to get the real ID
    IP->setMoreFragments(false);
    IP->setDontFragment(false);
    IP->setFragmentOffset(0);
    IP->setDiffServCodePoint(0); // Faked...
    IP->setBitLength(160);

    UDP->setSourcePort(ntohs(addrbuf->sin_port));
    UDP->setDestinationPort(getParentModule()->getSubmodule("overlay", 0)->
                            gate("appIn")->getNextGate()->getOwnerModule()->
                            par("localPort").longValue());

    UDP->setByteLength(8);

    // Done...
    UDP->encapsulate(payload);
    IP->encapsulate(UDP);
    delete[] buf;
    delete addr;
    return IP;

parse_error:
    delete IP;
    delete UDP;
    delete[] buf;
    delete addr;
    delete payload;
    return NULL;
}

char * UdpOutDevice::encapsulate ( cPacket *  msg, unsigned int *  length, sockaddr **  addr, socklen_t *  addrlen  )

protectedvirtual

Converts an IP datagram to a data block for sending it to the (realworld) network.

Parameters

msg	A pointer to the message to be converted
length	A pointer to an int that will hold the length of the converted data
addr	The destination address
addrlen	The length of the address

Returns

A pointer to the converted data

Implements RealworldConnector.

Definition at line 36 of file UdpOutDevice.cc.

{
    cPacket* payloadMsg = NULL;
    char* payload = NULL;
    sockaddr_in* addrbuf = NULL;

    unsigned int payloadLen;

    IPDatagram* IP = check_and_cast<IPDatagram*>(msg);
    // FIXME: Cast ICMP-Messages
    UDPPacket* UDP = dynamic_cast<UDPPacket*>(IP->decapsulate());

    if (!UDP) {
        EV << "[UdpOutDevice::encapsulate()]\n"
           << "    Can't parse non-UDP packets (e.g. ICMP) (yet)"
           << endl;

        goto parse_error;
    }

    // TODO(?) Handle fragmented packets
    if( IP->getMoreFragments() ) {
        EV << "[UdpOutDevice::encapsulate()]\n"
            << "    Can't parse fragmented packets"
            << endl;
        goto parse_error;
    }

    payloadMsg = UDP->decapsulate();

    // parse payload
    payload = parser->encapsulatePayload(payloadMsg, &payloadLen);
    if (!payload) {
        EV << "[UdpOutDevice::encapsulate()]\n"
           << "    Can't parse packet payload, dropping packet"
           << endl;
        goto parse_error;
    }

    if (payloadLen > mtu) {
        EV << "[UdpOutDevice::encapsulate()]\n"
           << "    Encapsulating packet failed: packet too long"
           << endl;
        goto parse_error;
    }

    *length = payloadLen;

    // create sockaddr
    addrbuf = new sockaddr_in;
    addrbuf->sin_family = AF_INET;
    addrbuf->sin_port = htons(UDP->getDestinationPort());
    addrbuf->sin_addr.s_addr = htonl(IP->getDestAddress().getInt());
    *addrlen = sizeof(sockaddr_in);
    *addr = (sockaddr*) addrbuf;

    delete IP;
    delete UDP;
    delete payloadMsg;
    return payload;

parse_error:
    delete IP;
    delete UDP;
    delete payloadMsg;
    delete payload;
    return NULL;

}

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The documentation for this class was generated from the following files:

• UdpOutDevice.h
• UdpOutDevice.cc