llcircuit.h

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#ifndef LL_LLCIRCUIT_H
#define LL_LLCIRCUIT_H

#include <map>
#include <vector>

#include "llerror.h"

#include "lltimer.h"
#include "timing.h"
#include "net.h"
#include "llhost.h"
#include "llpacketack.h"
#include "lluuid.h"
#include "llthrottle.h"

//
// Constants
//
const F32 PING_INTERVAL_MAX = 100.f;
const F32 PING_INTERVAL_ALARM = 50.f;


const F32 LL_AVERAGED_PING_ALPHA = 0.2f;  // relaxation constant on ping running average
const F32 LL_AVERAGED_PING_MAX = 2000;    // msec
const F32 LL_AVERAGED_PING_MIN =  100;    // msec  // IW: increased to avoid retransmits when a process is slow

const U32 INITIAL_PING_VALUE_MSEC = 1000; // initial value for the ping delay, or for ping delay for an unknown circuit

const TPACKETID LL_MAX_OUT_PACKET_ID = 0x01000000;

// 0 - flags
// [1,4] - packetid
// 5 - data offset (after message name)
const U8 LL_PACKET_ID_SIZE = 6;

const S32 LL_MAX_RESENT_PACKETS_PER_FRAME = 100;
const S32 LL_MAX_ACKED_PACKETS_PER_FRAME = 200;

//
// Prototypes and Predefines
//
class LLMessageSystem;
class LLEncodedDatagramService;
class LLSD;

//
// Classes
//


class LLCircuitData
{
public:
        LLCircuitData(const LLHost &host, TPACKETID in_id);
        ~LLCircuitData();

        S32             resendUnackedPackets(const F64 now);
        void    clearDuplicateList(TPACKETID oldest_id);


        void    dumpResendCountAndReset(); // Used for tracking how many resends are being done on a circuit.



        // Public because stupid message system callbacks uses it.
        void            pingTimerStart();
        void            pingTimerStop(const U8 ping_id);
        void                    ackReliablePacket(TPACKETID packet_num);

        // remote computer information
        const LLUUID& getRemoteID() const { return mRemoteID; }
        const LLUUID& getRemoteSessionID() const { return mRemoteSessionID; }
        void setRemoteID(const LLUUID& id) { mRemoteID = id; }
        void setRemoteSessionID(const LLUUID& id) { mRemoteSessionID = id; }

        void            setTrusted(BOOL t);

        // The local end point ID is used when establishing a trusted circuit.
        // no matching set function for getLocalEndPointID()
        // mLocalEndPointID should only ever be setup in the LLCircuitData constructor
        const           LLUUID& getLocalEndPointID() const { return mLocalEndPointID; }

        U32             getPingDelay() const;
        S32                             getPingsInTransit() const                       { return mPingsInTransit; }

        // ACCESSORS
        BOOL            isAlive() const;
        BOOL            isBlocked() const;
        BOOL            getAllowTimeout() const;
        F32                     getPingDelayAveraged();
        F32                     getPingInTransitTime();
        U32                     getPacketsIn() const;
        S32                     getBytesIn() const;
        S32                     getBytesOut() const;
        U32                     getPacketsOut() const;
        U32                     getPacketsLost() const;
        TPACKETID       getPacketOutID() const;
        BOOL            getTrusted() const;
        F32 getAgeInSeconds() const;
        S32                     getUnackedPacketCount() const   { return mUnackedPacketCount; }
        S32                     getUnackedPacketBytes() const   { return mUnackedPacketBytes; }
        F64         getNextPingSendTime() const { return mNextPingSendTime; }

        LLThrottleGroup &getThrottleGroup()             {       return mThrottles; }

        class less
        {
        public:
                bool operator()(const LLCircuitData* lhs, const LLCircuitData* rhs) const
                {
                        if (lhs->getNextPingSendTime() < rhs->getNextPingSendTime())
                        {
                                return true;
                        }
                        else if (lhs->getNextPingSendTime() > rhs->getNextPingSendTime())
                        {
                                return false;
                        }
                        else return lhs > rhs;
                }
        };

        //
        // Debugging stuff (not necessary for operation)
        //
        void                                    checkPeriodTime();              // Reset per-period counters if necessary.
        friend std::ostream&    operator<<(std::ostream& s, LLCircuitData &circuit);
        void getInfo(LLSD& info) const;

        friend class LLCircuit;
        friend class LLMessageSystem;
        friend class LLEncodedDatagramService;
        friend void crash_on_spaceserver_timeout (const LLHost &host, void *); // HACK, so it has access to setAlive() so it can send a final shutdown message.
protected:
        TPACKETID               nextPacketOutID();
        void                            setPacketInID(TPACKETID id);
        void                                    checkPacketInID(TPACKETID id, BOOL receive_resent);
        void                    setPingDelay(U32 ping);
        BOOL                    checkCircuitTimeout();  // Return FALSE if the circuit is dead and should be cleaned up

        void                    addBytesIn(S32 bytes);
        void                    addBytesOut(S32 bytes);

        U8                              nextPingID()                    { mLastPingID++; return mLastPingID; }

        BOOL                    updateWatchDogTimers(LLMessageSystem *msgsys);  // Return FALSE if the circuit is dead and should be cleaned up

        void                    addReliablePacket(S32 mSocket, U8 *buf_ptr, S32 buf_len, LLReliablePacketParams *params);
        BOOL                    isDuplicateResend(TPACKETID packetnum);
        // Call this method when a reliable message comes in - this will
        // correctly place the packet in the correct list to be acked
        // later. RAack = requested ack
        BOOL collectRAck(TPACKETID packet_num);


        void                    setTimeoutCallback(void (*callback_func)(const LLHost &host, void *user_data), void *user_data);



        void                    setAlive(BOOL b_alive);
        void                    setAllowTimeout(BOOL allow);

protected:
        // Identification for this circuit.
        LLHost mHost;
        LLUUID mRemoteID;
        LLUUID mRemoteSessionID;

        LLThrottleGroup mThrottles;

        TPACKETID               mWrapID;

        // Current packet IDs of incoming/outgoing packets
        // Used for packet sequencing/packet loss detection.
        TPACKETID               mPacketsOutID;
        TPACKETID               mPacketsInID;
        TPACKETID               mHighestPacketID;


        // Callback and data to run in the case of a circuit timeout.
        // Used primarily to try and reconnect to servers if they crash/die.
        void    (*mTimeoutCallback)(const LLHost &host, void *user_data);
        void    *mTimeoutUserData;

        BOOL    mTrusted;                                       // Is this circuit trusted?
        BOOL    mbAllowTimeout;                         // Machines can "pause" circuits, forcing them not to be dropped

        BOOL    mbAlive;                                        // Indicates whether a circuit is "alive", i.e. responded to pings

        BOOL    mBlocked;                                       // Blocked is true if the circuit is hosed, i.e. far behind on pings

        // Not sure what the difference between this and mLastPingSendTime is
        F64             mPingTime;                                      // Time at which a ping was sent.

        F64             mLastPingSendTime;                      // Time we last sent a ping
        F64             mLastPingReceivedTime;          // Time we last received a ping
        F64     mNextPingSendTime;          // Time to try and send the next ping
        S32             mPingsInTransit;                        // Number of pings in transit
        U8              mLastPingID;                            // ID of the last ping that we sent out


        // Used for determining the resend time for reliable resends.
        U32             mPingDelay;             // raw ping delay
        F32             mPingDelayAveraged;     // averaged ping delay (fast attack/slow decay)

        typedef std::map<TPACKETID, U64> packet_time_map;

        packet_time_map                                                 mPotentialLostPackets;
        packet_time_map                                                 mRecentlyReceivedReliablePackets;
        std::vector<TPACKETID> mAcks;

        typedef std::map<TPACKETID, LLReliablePacket *> reliable_map;
        typedef reliable_map::iterator                                  reliable_iter;

        reliable_map                                                    mUnackedPackets;
        reliable_map                                                    mFinalRetryPackets;

        S32                                                                             mUnackedPacketCount;
        S32                                                                             mUnackedPacketBytes;


        LLUUID                                                                  mLocalEndPointID;

        //
        // These variables are being used for statistical and debugging purpose ONLY,
        // as far as I can tell.
        //

        U32             mPacketsOut;
        U32             mPacketsIn;
        S32             mPacketsLost;
        S32             mBytesIn;
        S32             mBytesOut;

        F32             mLastPeriodLength;              // seconds
        S32             mBytesInLastPeriod;
        S32             mBytesOutLastPeriod;
        S32             mBytesInThisPeriod;
        S32             mBytesOutThisPeriod;
        F32             mPeakBPSIn;                             // bits per second, max of all period bps
        F32             mPeakBPSOut;                    // bits per second, max of all period bps
        F64             mPeriodTime;
        LLTimer mExistenceTimer;            // initialized when circuit created, used to track bandwidth numbers

        S32             mCurrentResendCount;    // Number of resent packets since last spam
};


// Actually a singleton class -- the global messagesystem
// has a single LLCircuit member.
class LLCircuit
{
public:
        // CREATORS
        LLCircuit();
        ~LLCircuit();

        // ACCESSORS
        LLCircuitData* findCircuit(const LLHost& host) const;
        BOOL isCircuitAlive(const LLHost& host) const;
        
        // MANIPULATORS
        LLCircuitData   *addCircuitData(const LLHost &host, TPACKETID in_id);
        void                    removeCircuitData(const LLHost &host);

        void                updateWatchDogTimers(LLMessageSystem *msgsys);
        void                    resendUnackedPackets(S32& unacked_list_length, S32& unacked_list_size);

        // this method is called during the message system processAcks()
        // to send out any acks that did not get sent already. 
        void sendAcks();

        friend std::ostream& operator<<(std::ostream& s, LLCircuit &circuit);
        void getInfo(LLSD& info) const;

        void                    dumpResends();

        typedef std::map<LLHost, LLCircuitData*> circuit_data_map;

        void getCircuitRange(
                const LLHost& key,
                circuit_data_map::iterator& first,
                circuit_data_map::iterator& end);

        // Lists that optimize how many circuits we need to traverse a frame
        // HACK - this should become protected eventually, but stupid !@$@# message system/circuit classes are jumbling things up.
        circuit_data_map mUnackedCircuitMap; // Map of circuits with unacked data
        circuit_data_map mSendAckMap; // Map of circuits which need to send acks
protected:
        circuit_data_map mCircuitData;

        typedef std::set<LLCircuitData *, LLCircuitData::less> ping_set_t; // Circuits sorted by next ping time
        ping_set_t mPingSet;

        // This variable points to the last circuit data we found to
        // optimize the many, many times we call findCircuit. This may be
        // set in otherwise const methods, so it is declared mutable.
        mutable LLCircuitData* mLastCircuit;
};
#endif

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