inet::sctp::SctpNatHook Class Reference

#include <SctpNatHook.h>

Inheritance diagram for inet::sctp::SctpNatHook:

Public Member Functions
	SctpNatHook ()
virtual	~SctpNatHook ()
virtual Result	datagramPreRoutingHook (Packet *packet) override
	This is the first hook called by the network protocol before it routes a datagram that was received from the lower layer. More...
virtual Result	datagramForwardHook (Packet *packet) override
	This is the second hook called by the network protocol before it sends a datagram to the lower layer. More...
virtual Result	datagramPostRoutingHook (Packet *packet) override
	This is the last hook called by the network protocol before it sends a datagram to the lower layer. More...
virtual Result	datagramLocalInHook (Packet *packet) override
	This is the last hook called by the network protocol before it sends a datagram to the upper layer. More...
virtual Result	datagramLocalOutHook (Packet *packet) override
	This is the first hook called by the network protocol before it routes a datagram that was received from the upper layer. More...

Protected Member Functions
void	initialize () override
void	finish () override
void	sendBackError (SctpHeader *sctp)

Protected Attributes
IPv4 *	ipLayer
ModuleRefByPar< SctpNatTable >	natTable
ModuleRefByPar< IRoutingTable >	rt
ModuleRefByPar< IInterfaceTable >	ift
uint64_t	nattedPackets

Additional Inherited Members
Private Types inherited from inet::INetfilter::IHook
enum	Type {   PREROUTING, LOCALIN, FORWARD, POSTROUTING,   LOCALOUT }
enum	Result { ACCEPT, DROP, QUEUE, STOLEN }
Private Member Functions inherited from inet::NetfilterBase::HookBase
virtual	~HookBase ()
void	registeredTo (INetfilter *nf)
void	unregisteredFrom (INetfilter *nf)
bool	isRegisteredHook (INetfilter *nf)
Private Member Functions inherited from inet::INetfilter::IHook
virtual	~IHook ()
Private Attributes inherited from inet::NetfilterBase::HookBase
std::vector< INetfilter * >	netfilters

Constructor & Destructor Documentation

SctpNatHook()

inet::sctp::SctpNatHook::SctpNatHook

(

)

{
    ipLayer = nullptr;
    nattedPackets = 0;
}

~SctpNatHook()

inet::sctp::SctpNatHook::~SctpNatHook ( )

virtual

{
}

Member Function Documentation

datagramForwardHook()

INetfilter::IHook::Result inet::sctp::SctpNatHook::datagramForwardHook ( Packet *  datagram )

overridevirtual

This is the second hook called by the network protocol before it sends a datagram to the lower layer.

This is done after the datagramPreRoutingHook or the datagramLocalInHook is called and the datagram is routed.

Implements inet::INetfilter::IHook.

{
    SctpNatEntry *entry;
    SctpChunk *chunk;
    const auto& tag = datagram->findTag<InterfaceReq>();
    const NetworkInterface *outIE = (tag != nullptr ? ift->getInterfaceById(tag->getInterfaceId()) : nullptr);
 
    const auto& inIeTag = datagram->findTag<InterfaceInd>();
    const NetworkInterface *inIE = (inIeTag != nullptr ? ift->getInterfaceById(inIeTag->getInterfaceId()) : nullptr);
 
    const auto& dgram = removeNetworkProtocolHeader<Ipv4Header>(datagram);
 
    if (!dgram) {
        insertNetworkProtocolHeader(datagram, Protocol::ipv4, dgram);
        return INetfilter::IHook::ACCEPT;
    }
    if (dgram->isFragment()) {
        // TODO process fragmented packets
        insertNetworkProtocolHeader(datagram, Protocol::ipv4, dgram);
        return INetfilter::IHook::ACCEPT;
    }
    if (SctpAssociation::getAddressLevel(dgram->getSrcAddress()) != 3) {
        insertNetworkProtocolHeader(datagram, Protocol::ipv4, dgram);
        return INetfilter::IHook::ACCEPT;
    }
    const auto& networkHeader = staticPtrCast<Ipv4Header>(dgram->dupShared());
    natTable->printNatTable();
    auto& sctpMsg = datagram->removeAtFront<SctpHeader>();
    Ptr<SctpHeader> sctp = staticPtrCast<SctpHeader>(sctpMsg->dupShared());
    unsigned int numberOfChunks = sctpMsg->getSctpChunksArraySize();
    if (numberOfChunks == 1) {
        chunk = sctpMsg->peekFirstChunk();
    }
    else {
        chunk = sctpMsg->peekLastChunk();
    }
    EV << "findEntry for " << dgram->getSrcAddress() << ":" << sctpMsg->getSrcPort() << " to " << dgram->getDestAddress() << ":" << sctpMsg->getDestPort() << " vTag=" << sctpMsg->getVTag() << "\n";
    if (chunk->getSctpChunkType() == INIT || chunk->getSctpChunkType() == INIT_ACK || chunk->getSctpChunkType() == ASCONF) {
        entry = new SctpNatEntry();
        entry->setLocalAddress(dgram->getSrcAddress());
        entry->setLocalPort(sctpMsg->getSrcPort());
        entry->setGlobalAddress(dgram->getDestAddress());
        entry->setGlobalPort(sctpMsg->getDestPort());
        entry->setNattedAddress(outIE->getProtocolData<Ipv4InterfaceData>()->getIPAddress());
        entry->setNattedPort(sctpMsg->getSrcPort());
        entry->setGlobalVTag(sctpMsg->getVTag());
        if (chunk->getSctpChunkType() == INIT) {
            SctpInitChunk *initChunk = check_and_cast<SctpInitChunk *>(chunk);
            entry->setLocalVTag(initChunk->getInitTag());
        }
        else if (chunk->getSctpChunkType() == INIT_ACK) {
            SctpInitAckChunk *initAckChunk = check_and_cast<SctpInitAckChunk *>(chunk);
            entry->setLocalVTag(initAckChunk->getInitTag());
        }
        else if (chunk->getSctpChunkType() == ASCONF) {
            SctpAsconfChunk *asconfChunk = check_and_cast<SctpAsconfChunk *>(chunk);
            entry->setLocalVTag(asconfChunk->getPeerVTag());
        }
        networkHeader->setSrcAddress(outIE->getProtocolData<Ipv4InterfaceData>()->getIPAddress());
        sctp->setSrcPort(entry->getNattedPort());
        natTable->natEntries.push_back(entry);
        natTable->printNatTable();
    }
    else {
        EV << "other chunkType: " << (chunk->getSctpChunkType() == COOKIE_ECHO ? "Cookie_Echo" : "other") << ", VTag=" << sctpMsg->getVTag() << "\n";
        entry = natTable->findNatEntry(networkHeader->getSrcAddress(), sctp->getSrcPort(), networkHeader->getDestAddress(), sctp->getDestPort(), sctp->getVTag());
        if (entry == nullptr) {
            EV << "no entry found\n";
            entry = natTable->findNatEntry(networkHeader->getSrcAddress(), sctp->getSrcPort(), networkHeader->getDestAddress(), sctp->getDestPort(), 0);
            if (entry == nullptr) {
                EV << "send back error message dgram=" << networkHeader << "\n";
                sendBackError(sctp.get());
                sctp->setSrcPort(sctpMsg->getDestPort());
                sctp->setDestPort(sctpMsg->getSrcPort());
                Ipv4Address tmpaddr = dgram->getDestAddress();
                networkHeader->setDestAddress(dgram->getSrcAddress());
                if (!tmpaddr.isUnspecified())
                    networkHeader->setSrcAddress(tmpaddr);
                networkHeader->setTotalLengthField(sctp->getChunkLength() + B(20));
                insertTransportProtocolHeader(datagram, Protocol::sctp, sctp);
                insertNetworkProtocolHeader(datagram, Protocol::ipv4, networkHeader);
                datagram->addTagIfAbsent<NextHopAddressReq>()->setNextHopAddress(networkHeader->getDestAddress());
                datagram->addTagIfAbsent<InterfaceReq>()->setInterfaceId(CHK(inIE)->getInterfaceId());
                return INetfilter::IHook::ACCEPT;
            }
            else {
                EV << "VTag doesn't match: old VTag=" << entry->getLocalVTag() << ", new VTag=" << sctpMsg->getVTag() << "\n";
                entry->setLocalVTag(sctpMsg->getVTag());
                networkHeader->setSrcAddress(outIE->getProtocolData<Ipv4InterfaceData>()->getIPAddress());
                sctp->setSrcPort(entry->getNattedPort());
                EV << "srcAddress set to " << dgram->getSrcAddress() << ", srcPort set to " << sctpMsg->getSrcPort() << "\n";
            }
        }
        else {
            networkHeader->setSrcAddress(outIE->getProtocolData<Ipv4InterfaceData>()->getIPAddress());
            sctp->setSrcPort(entry->getNattedPort());
            EV << "srcAddress set to " << dgram->getSrcAddress() << ", srcPort set to " << sctpMsg->getSrcPort() << "\n";
        }
    }
    nattedPackets++;
    insertTransportProtocolHeader(datagram, Protocol::sctp, sctp);
    insertNetworkProtocolHeader(datagram, Protocol::ipv4, networkHeader);
    return INetfilter::IHook::ACCEPT;
}

datagramLocalInHook()

virtual Result inet::sctp::SctpNatHook::datagramLocalInHook ( Packet *  datagram )

inlineoverridevirtual

This is the last hook called by the network protocol before it sends a datagram to the upper layer.

This is done after the datagramPreRoutingHook is called and the datagram is routed.

Implements inet::INetfilter::IHook.

{ return ACCEPT; }

datagramLocalOutHook()

virtual Result inet::sctp::SctpNatHook::datagramLocalOutHook ( Packet *  datagram )

inlineoverridevirtual

This is the first hook called by the network protocol before it routes a datagram that was received from the upper layer.

The nextHopAddress is ignored when the outputNetworkInterface is a nullptr. After this is done

Implements inet::INetfilter::IHook.

{ return ACCEPT; }

datagramPostRoutingHook()

virtual Result inet::sctp::SctpNatHook::datagramPostRoutingHook ( Packet *  datagram )

inlineoverridevirtual

This is the last hook called by the network protocol before it sends a datagram to the lower layer.

Implements inet::INetfilter::IHook.

{ return ACCEPT; }

datagramPreRoutingHook()

INetfilter::IHook::Result inet::sctp::SctpNatHook::datagramPreRoutingHook ( Packet *  datagram )

overridevirtual

This is the first hook called by the network protocol before it routes a datagram that was received from the lower layer.

The nextHopAddress is ignored when the outputNetworkInterface is nullptr.

Implements inet::INetfilter::IHook.

{
    SctpNatEntry *entry;
    SctpChunk *chunk;
 
    const auto& dgram = removeNetworkProtocolHeader<Ipv4Header>(datagram);
    const auto& networkHeader = staticPtrCast<Ipv4Header>(dgram->dupShared());
    if (SctpAssociation::getAddressLevel(dgram->getSourceAddress()) == 3) {
        insertNetworkProtocolHeader(datagram, Protocol::ipv4, dgram);
        return INetfilter::IHook::ACCEPT;
    }
 
    if (dgram->isFragment()) {
        // TODO process fragmented packets
        insertNetworkProtocolHeader(datagram, Protocol::ipv4, dgram);
        return INetfilter::IHook::ACCEPT;
    }
 
    natTable->printNatTable();
    bool local = ((rt->isLocalAddress(dgram->getDestinationAddress())) && (SctpAssociation::getAddressLevel(dgram->getSourceAddress()) == 3));
    auto& sctpMsg = datagram->removeAtFront<SctpHeader>();
    Ptr<SctpHeader> sctp = staticPtrCast<SctpHeader>(sctpMsg->dupShared());
    unsigned int numberOfChunks = sctpMsg->getSctpChunksArraySize();
    if (numberOfChunks == 1)
        chunk = sctpMsg->peekFirstChunk();
    else
        chunk = sctpMsg->peekLastChunk();
    if (!local) {
        entry = natTable->getEntry(dgram->getSourceAddress(), sctpMsg->getSrcPort(), dgram->getDestinationAddress(), sctpMsg->getDestPort(), sctpMsg->getVTag());
        EV_INFO << "getEntry for " << dgram->getSourceAddress() << ":" << sctpMsg->getSrcPort() << " to " << dgram->getDestinationAddress() << ":" << sctpMsg->getDestPort() << " peerVTag=" << sctpMsg->getVTag() << "\n";
        uint32_t numberOfChunks = sctpMsg->getSctpChunksArraySize();
        if (entry == nullptr) {
            EV_INFO << "no entry found\n";
            if (numberOfChunks == 1)
                chunk = sctpMsg->peekFirstChunk();
            else
                chunk = sctpMsg->peekLastChunk();
            if (chunk->getSctpChunkType() == INIT || chunk->getSctpChunkType() == ASCONF) {
                EV_INFO << "could be an Init collision\n";
                entry = natTable->getSpecialEntry(dgram->getSourceAddress(), sctpMsg->getSrcPort(), dgram->getDestinationAddress(), sctpMsg->getDestPort());
                if (entry != nullptr) {
                    if (chunk->getSctpChunkType() == INIT) {
                        SctpInitChunk *initChunk = check_and_cast<SctpInitChunk *>(chunk);
                        entry->setLocalVTag(initChunk->getInitTag());
                        EV_INFO << "InitTag=" << initChunk->getInitTag() << "\n";
                    }
                    else if (chunk->getSctpChunkType() == ASCONF) {
                        SctpAsconfChunk *asconfChunk = check_and_cast<SctpAsconfChunk *>(chunk);
                        entry->setLocalVTag(asconfChunk->getPeerVTag());
                    }
                    networkHeader->setDestinationAddress(entry->getLocalAddress().toIpv4());
                    sctp->setDestPort(entry->getLocalPort());
                    EV_INFO << "destAddress set to " << dgram->getDestinationAddress() << ", destPort set to " << sctp->getDestPort() << "\n";
                }
                else {
                    insertTransportProtocolHeader(datagram, Protocol::sctp, sctp);
                    insertNetworkProtocolHeader(datagram, Protocol::ipv4, networkHeader);
                    return INetfilter::IHook::DROP;
                }
            }
            else {
               /* SctpChunk *schunk = nullptr;
                if (numberOfChunks > 0) {
                    EV << "number of chunks=" << numberOfChunks << "\n";
                    for (uint32_t i = 0; i < numberOfChunks; i++) {
                        schunk = (SctpChunk *)(sctpMsg->removeChunk());
                        if (schunk->getSctpChunkType() == DATA)
                            delete (SctpSimpleMessage *)schunk->decapsulate();
                        EV << "delete chunk " << schunk->getName() << "\n";
                        delete schunk;
                    }
                }*/
                insertTransportProtocolHeader(datagram, Protocol::sctp, sctp);
                insertNetworkProtocolHeader(datagram, Protocol::ipv4, networkHeader);
                return INetfilter::IHook::DROP;
            }
        }
        else {
            networkHeader->setDestinationAddress(entry->getLocalAddress().toIpv4());
            sctp->setDestPort(entry->getLocalPort());
            if (entry->getGlobalVTag() == 0 && chunk->getSctpChunkType() == INIT_ACK) {
                SctpInitAckChunk *initAckChunk = check_and_cast<SctpInitAckChunk *>(chunk);
                entry->setGlobalVTag(initAckChunk->getInitTag());
            }
            EV << "destAddress set to " << dgram->getDestinationAddress() << ", destPort set to " << sctpMsg->getDestPort() << "\n";
        }
    }
    else {
        if (chunk->getSctpChunkType() == INIT) {
            EV << "getLocALEntry for " << dgram->getSourceAddress() << ":" << sctpMsg->getSrcPort() << " to " << dgram->getDestinationAddress() << ":" << sctpMsg->getDestPort() << " peerVTag=" << sctpMsg->getVTag() << "\n";
            entry = natTable->getLocalInitEntry(dgram->getDestinationAddress(), sctpMsg->getSrcPort(), sctpMsg->getDestPort());
            if (entry == nullptr) {
                entry = new SctpNatEntry();
                entry->setLocalAddress(dgram->getSourceAddress());
                entry->setLocalPort(sctpMsg->getSrcPort());
                entry->setGlobalAddress(dgram->getDestinationAddress());
                entry->setGlobalPort(sctpMsg->getDestPort());
                entry->setNattedPort(sctpMsg->getSrcPort());
                entry->setNattedAddress(dgram->getDestinationAddress());
                SctpInitChunk *initChunk = check_and_cast<SctpInitChunk *>(chunk);
                entry->setGlobalVTag(initChunk->getInitTag());
                natTable->natEntries.push_back(entry);
                EV << "added entry for local deliver\n";
                natTable->printNatTable();
                insertTransportProtocolHeader(datagram, Protocol::sctp, sctp);
                insertNetworkProtocolHeader(datagram, Protocol::ipv4, networkHeader);
                return INetfilter::IHook::DROP;
            }
            else {
                SctpNatEntry *entry2 = new SctpNatEntry();
                entry2->setLocalAddress(dgram->getSourceAddress());
                entry2->setLocalPort(sctpMsg->getSrcPort());
                entry2->setGlobalAddress(entry->getGlobalAddress());
                entry2->setGlobalPort(sctpMsg->getDestPort());
                entry2->setNattedPort(sctpMsg->getSrcPort());
                entry2->setNattedAddress(entry->getGlobalAddress());
                SctpInitChunk *initChunk = check_and_cast<SctpInitChunk *>(chunk);
                entry2->setGlobalVTag(initChunk->getInitTag());
                natTable->natEntries.push_back(entry2);
                networkHeader->setDestinationAddress(entry->getLocalAddress().toIpv4());
                sctp->setDestPort(entry->getLocalPort());
                networkHeader->setSourceAddress(entry->getGlobalAddress().toIpv4());
                sctp->setSrcPort(entry->getGlobalPort());
                EV << "added additional entry for local deliver\n";
                natTable->printNatTable();
                EV << "destAddress set to " << dgram->getDestinationAddress() << ", destPort set to " << sctpMsg->getDestPort() << "\n";
            }
        }
        else {
            EV << "no INIT: destAddr=" << dgram->getDestinationAddress() << " destPort=" << sctpMsg->getDestPort() << " srcPort=" << sctpMsg->getSrcPort() << " vTag=" << sctpMsg->getVTag() << "\n";
            entry = natTable->getLocalEntry(dgram->getDestinationAddress(), sctpMsg->getSrcPort(), sctpMsg->getDestPort(), sctpMsg->getVTag());
            if (entry != nullptr) {
                networkHeader->setDestinationAddress(entry->getLocalAddress().toIpv4());
                sctp->setDestPort(entry->getLocalPort());
                networkHeader->setSourceAddress(entry->getGlobalAddress().toIpv4());
                sctp->setSrcPort(entry->getGlobalPort());
            }
            else {
                EV << "no entry found\n";
                insertTransportProtocolHeader(datagram, Protocol::sctp, sctp);
                insertNetworkProtocolHeader(datagram, Protocol::ipv4, networkHeader);
 
                return INetfilter::IHook::DROP;
            }
        }
    }
 
    nattedPackets++;
    insertTransportProtocolHeader(datagram, Protocol::sctp, sctp);
    insertNetworkProtocolHeader(datagram, Protocol::ipv4, networkHeader);
    return INetfilter::IHook::ACCEPT;
}

finish()

void inet::sctp::SctpNatHook::finish ( )

overrideprotected

{
    auto ipv4 = dynamic_cast<INetfilter *>(getModuleByPath("^.ipv4.ip"));
    if (isRegisteredHook(ipv4))
        ipv4->unregisterHook(this);
    ipLayer = nullptr;
    EV_INFO << getFullPath() << ": Natted packets: " << nattedPackets << "\n";
}

initialize()

void inet::sctp::SctpNatHook::initialize ( )

overrideprotected

{
    rt.reference(this, "routingTableModule", true);
    ift.reference(this, "interfaceTableModule", true);
    natTable.reference(this, "natTableModule", true);
    auto ipv4 = dynamic_cast<INetfilter *>(getModuleByPath("^.ipv4.ip"));
    ipv4->registerHook(0, this);
}

sendBackError()

void inet::sctp::SctpNatHook::sendBackError ( SctpHeader *  sctp )

protected

{
//    SctpHeader *sctpmsg = new SctpHeader();
    delete sctp->removeFirstChunk();
    sctp->setChunkLength(B(SCTP_COMMON_HEADER));
    SctpErrorChunk *errorChunk = new SctpErrorChunk("NatError");
    errorChunk->setSctpChunkType(ERRORTYPE);
    errorChunk->setByteLength(4);
    SctpSimpleErrorCauseParameter *cause = new SctpSimpleErrorCauseParameter("Cause");
    cause->setParameterType(MISSING_NAT_ENTRY);
    cause->setByteLength(4);
//    cause->encapsulate(dgram->dup());
    errorChunk->setMBit(true);
    errorChunk->setTBit(true);
    errorChunk->addParameters(cause);
    sctp->appendSctpChunks(errorChunk);
}

Referenced by datagramForwardHook().

Member Data Documentation

ift

ModuleRefByPar<IInterfaceTable> inet::sctp::SctpNatHook::ift

protected

Referenced by datagramForwardHook(), and initialize().

ipLayer

IPv4* inet::sctp::SctpNatHook::ipLayer

protected

Referenced by finish(), and SctpNatHook().

natTable

ModuleRefByPar<SctpNatTable> inet::sctp::SctpNatHook::natTable

protected

Referenced by datagramForwardHook(), datagramPreRoutingHook(), and initialize().

nattedPackets

uint64_t inet::sctp::SctpNatHook::nattedPackets

protected

Referenced by datagramForwardHook(), datagramPreRoutingHook(), finish(), and SctpNatHook().

rt

ModuleRefByPar<IRoutingTable> inet::sctp::SctpNatHook::rt

protected

Referenced by datagramPreRoutingHook(), and initialize().

---

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

• SctpNatHook.h
• SctpNatHook.cc