inet::ieee80211::BasicReassembly Class Reference

#include <BasicReassembly.h>

Inheritance diagram for inet::ieee80211::BasicReassembly:

Classes
struct	Key
struct	Value

Public Member Functions
virtual	~BasicReassembly ()
virtual Ieee80211DataOrMgmtFrame *	addFragment (Ieee80211DataOrMgmtFrame *frame) override
	Add a fragment to the reassembly buffer. More...
virtual void	purge (const MACAddress &address, int tid, int startSeqNumber, int endSeqNumber) override
	Discard fragments from the reassembly buffer. More...
Public Member Functions inherited from inet::ieee80211::IReassembly
virtual	~IReassembly ()

Protected Types
typedef std::map< Key, Value >	FragmentsMap

Protected Attributes
FragmentsMap	fragmentsMap

Member Typedef Documentation

typedef std::map<Key,Value> inet::ieee80211::BasicReassembly::FragmentsMap

protected

Constructor & Destructor Documentation

inet::ieee80211::BasicReassembly::~BasicReassembly ( )

virtual

{
    for (auto it = fragmentsMap.begin(); it != fragmentsMap.end(); ++it)
        delete it->second.frame;
}

Member Function Documentation

Ieee80211DataOrMgmtFrame * inet::ieee80211::BasicReassembly::addFragment ( Ieee80211DataOrMgmtFrame *  frame )

overridevirtual

Add a fragment to the reassembly buffer.

If the new fragment completes a frame, then the reassembled frame is returned (and fragments are removed from the buffer), otherwise the function returns nullptr.

Implements inet::ieee80211::IReassembly.

Referenced by inet::ieee80211::RecipientMacDataService::defragment(), and inet::ieee80211::RecipientQoSMacDataService::defragment().

{
    // Frame is not fragmented
    if (!frame->getMoreFragments() && frame->getFragmentNumber() == 0)
        return frame;
    // FIXME: temporary fix for mgmt frames
    if (dynamic_cast<Ieee80211ManagementFrame*>(frame))
        return frame;
    // find entry for this frame
    Key key;
    key.macAddress = frame->getTransmitterAddress();
    key.tid = -1;
    if (frame->getType() == ST_DATA_WITH_QOS)
        if (Ieee80211DataFrame *qosDataFrame = dynamic_cast<Ieee80211DataFrame *>(frame))
            key.tid = qosDataFrame->getTid();
    key.seqNum = frame->getSequenceNumber();
    short fragNum = frame->getFragmentNumber();
    ASSERT(fragNum >= 0 && fragNum < MAX_NUM_FRAGMENTS);
    auto& value = fragmentsMap[key];

    // update entry
    uint16_t fragmentBit = 1 << fragNum;
    value.receivedFragments |= fragmentBit;
    if (!frame->getMoreFragments())
        value.allFragments = (fragmentBit << 1) - 1;
    if (!value.frame) {
        frame->setByteLength(0);  // needed for decapsulation of larger packet
        value.frame = check_and_cast_nullable<Ieee80211DataOrMgmtFrame *>(frame->decapsulate());
    }
    MACAddress txAddress = frame->getTransmitterAddress();
    delete frame;

    // if all fragments arrived, return assembled frame
    if (value.allFragments != 0 && value.allFragments == value.receivedFragments) {
        Ieee80211DataOrMgmtFrame *result = value.frame;
        // We need to restore some data from the carrying frame's header like TX address
        // TODO: Maybe we need to restore the fromDs, toDs fields as well when traveling through multiple APs
        // TODO: Are there any other fields that we need to restore?
        // TODO: SET TX ADDR WHEN THE FRAME ARRIVES FROM UPPER LAYER
        result->setTransmitterAddress(txAddress);
        fragmentsMap.erase(key);
        return result;
    }
    else
        return nullptr;
}

void inet::ieee80211::BasicReassembly::purge ( const MACAddress &  address, int  tid, int  startSeqNumber, int  endSeqNumber  )

overridevirtual

Discard fragments from the reassembly buffer.

Frames are identified by the transmitter address, the TID, and the sequence number range [startSeqNumber, endSeqNumber[. Set tid=-1 for non-QoS frames.

Implements inet::ieee80211::IReassembly.

{
    Key key;
    key.macAddress = address;
    key.tid = tid;
    key.seqNum = startSeqNumber;
    auto itStart = fragmentsMap.lower_bound(key);
    key.seqNum = endSeqNumber;
    auto itEnd = fragmentsMap.upper_bound(key);

    if (endSeqNumber < startSeqNumber) {
        for (auto it = itStart; it != fragmentsMap.end(); ) {
            delete it->second.frame;
            it = fragmentsMap.erase(it);
        }
        itStart = fragmentsMap.begin();
    }
    for (auto it = itStart; it != itEnd; ) {
        delete it->second.frame;
        it = fragmentsMap.erase(it);
    }
}

Member Data Documentation

FragmentsMap inet::ieee80211::BasicReassembly::fragmentsMap

protected

Referenced by addFragment(), purge(), and ~BasicReassembly().

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

• BasicReassembly.h
• BasicReassembly.cc