congestionwindow.cs

破解的飞信源代码

namespace NCindy.Protocol.RUDP.Window.Tahoe
{
    using NCindy.Protocol.RUDP;
    using NCindy.Protocol.RUDP.Packet;
    using NCindy.Protocol.RUDP.Window;
    using System;

    internal class CongestionWindow : AbstractWindow
    {
        internal readonly int _MaxSSthresh;
        internal int _outOfOrderCount;
        internal Phase _phase;
        internal double _ssthresh;

        internal CongestionWindow(RUDPSocket rudp) : base(rudp)
        {
            this._MaxSSthresh = 0x10000;
        }

        internal override void OnACK_UpdateWindow(RUDPOutgoingPacket packet)
        {
            this._outOfOrderCount = 0;
            if (base.CWND <= this._ssthresh)
            {
                this._phase = Phase.SlowStart;
            }
            else
            {
                this._phase = Phase.CongestionAvoidance;
            }
            if (this._phase == Phase.SlowStart)
            {
                base.CWND += base._rudp.MTU;
            }
            if (this._phase == Phase.CongestionAvoidance)
            {
                base.CWND += ((double) (base._rudp.MTU * base._rudp.MTU)) / base.CWND;
            }
            base.CWND = Math.Max((sbyte) Math.Min((double) base._awnd, base._cwnd), (sbyte) base._rudp._mtu);
            if (this._ssthresh < base.CWND)
            {
                this._ssthresh = Math.Min(0x10000, (int) base.CWND);
            }
        }

        internal override void OnEndFastRetransmit()
        {
            this._ssthresh = Math.Max((int) (base.CWND / 2), 2 * base._rudp._mtu);
            base.CWND = base._rudp._mtu;
            this._outOfOrderCount = 0;
            this._phase = Phase.SlowStart;
        }

        internal override void OnOutOfOrder(int startPacketId, int endPacketId)
        {
            this._outOfOrderCount++;
            if (this._outOfOrderCount >= 2)
            {
                this._phase = Phase.FastRetransmit;
                this._ssthresh = Math.Max((int) (base.FlightSize / 2), (int) (2 * base._rudp._mtu));
                this._ssthresh = Math.Min((double) this._MaxSSthresh, this._ssthresh);
                base.CWND = this._ssthresh + (this._outOfOrderCount * base._rudp._mtu);
                base._rudp.StartFastRetransmit(startPacketId, endPacketId);
            }
        }

        internal override void OnTimeOut_UpdateWindow()
        {
            this._outOfOrderCount = 0;
            if (base.CWND <= this._ssthresh)
            {
                this._phase = Phase.SlowStart;
            }
            else
            {
                this._phase = Phase.CongestionAvoidance;
            }
            if (this._phase == Phase.SlowStart)
            {
                base.CWND = base._rudp._mtu;
                this._ssthresh = Math.Max((int) (2 * base._rudp._mtu), (int) (base.FlightSize / 2));
            }
            if (this._phase == Phase.CongestionAvoidance)
            {
                this._ssthresh = Math.Max((int) (2 * base._rudp._mtu), (int) (base.FlightSize / 2));
                base.CWND = base._rudp._mtu;
            }
        }

        internal override void Reset()
        {
            base.Reset();
            base._cwnd = base._rudp._mtu;
            this._phase = Phase.SlowStart;
            this._ssthresh = this._MaxSSthresh;
        }
    }
}