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engine: rework how channel states & subchannels are handled #174

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44 changes: 17 additions & 27 deletions engine/net_chan.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -59,8 +59,6 @@ extern int NET_ReceiveStream( socket_handle nSock, char * buf, int len, int fla

#define BYTES2FRAGMENTS(i) (((i)+FRAGMENT_SIZE-1)/FRAGMENT_SIZE)

#define FLIPBIT(v,b) if (v&b) v &= ~b; else v |= b;

// We only need to checksum packets on the PC and only when we're actually sending them over the network.
static bool ShouldChecksumPackets()
{
Expand Down Expand Up @@ -105,9 +103,7 @@ void CNetChan::Clear()
{
if ( m_SubChannels[i].state == SUBCHANNEL_TOSEND )
{
int bit = 1<<i; // flip bit back since data was send yet

FLIPBIT(m_nOutReliableState, bit);
m_nOutReliableState.Flip(i);

m_SubChannels[i].Free();
}
Expand Down Expand Up @@ -438,8 +434,8 @@ CNetChan::CNetChan()
m_nOutSequenceNr = 1; // otherwise it looks like a
m_nInSequenceNr = 0;
m_nOutSequenceNrAck = 0;
m_nOutReliableState = 0; // our current reliable state
m_nInReliableState = 0; // last remote reliable state
m_nOutReliableState.ClearAll(); // our current reliable state
m_nInReliableState.ClearAll(); // last remote reliable state
// m_nLostPackets = 0;

m_ChallengeNr = 0;
Expand Down Expand Up @@ -525,8 +521,8 @@ void CNetChan::Setup(intp sock, netadr_t *adr, const char * name, INetChannelHan
m_nOutSequenceNr = 1; // otherwise it looks like a
m_nInSequenceNr = 0;
m_nOutSequenceNrAck = 0;
m_nOutReliableState = 0; // our current reliable state
m_nInReliableState = 0; // last remote reliable state
m_nOutReliableState.ClearAll(); // our current reliable state
m_nInReliableState.ClearAll(); // last remote reliable state
m_nChokedPackets = 0;
m_fClearTime = 0.0;

Expand Down Expand Up @@ -1182,7 +1178,7 @@ bool CNetChan::SendSubChannelData( bf_write &buf )
return false; // no data to send in any subchannel

// first write subchannel index
buf.WriteUBitLong( i, 3 );
buf.WriteUBitLong( i, SUBCHANNEL_BITS );

// write fragemnts for both streams
for ( i=0; i<MAX_STREAMS; i++ )
Expand Down Expand Up @@ -1493,9 +1489,7 @@ void CNetChan::UpdateSubChannels()
if ( bSendData )
{
// flip channel bit
int bit = 1<<freeSubChan->index;

FLIPBIT(m_nOutReliableState, bit);
m_nOutReliableState.Flip(freeSubChan->index);

freeSubChan->state = SUBCHANNEL_TOSEND;
freeSubChan->sendSeqNr = 0;
Expand Down Expand Up @@ -1631,7 +1625,7 @@ int CNetChan::SendDatagram(bf_write *datagram)
// Note, this only matters on the PC
int nCheckSumStart = send.GetNumBytesWritten();

send.WriteByte ( m_nInReliableState );
send.WriteBits( m_nInReliableState.Base(), MAX_SUBCHANNELS ); // RaphaelIT7: Originally used WriteByte- was changed to support easy changing of MAX_SUBCHANNELS

if ( m_nChokedPackets > 0 )
{
Expand Down Expand Up @@ -2240,7 +2234,8 @@ int CNetChan::ProcessPacketHeader( netpacket_t * packet )
}
}

int relState = packet->message.ReadByte(); // reliable state of 8 subchannels
CBitVec<MAX_SUBCHANNELS> relState; // RaphaelIT7: Added to allow easy changing of MAX_SUBCHANNELS
packet->message.ReadBits( relState.Base(), MAX_SUBCHANNELS ); // reliable state of all subchannels (RaphaelIT7: Previously ued ReadByte though was changed)
int nChoked = 0; // read later if choked flag is set
int i,j;

Expand Down Expand Up @@ -2309,14 +2304,12 @@ int CNetChan::ProcessPacketHeader( netpacket_t * packet )

for ( i = 0; i<MAX_SUBCHANNELS; i++ )
{
int bitmask = (1<<i);

// data of channel i has been acknowledged
subChannel_s * subchan = &m_SubChannels[i];

Assert( subchan->index == i);
Assert( subchan->index == i );

if ( (m_nOutReliableState & bitmask) == (relState & bitmask) )
if ( m_nOutReliableState.CompareBit(relState, i) )
{
if ( subchan->state == SUBCHANNEL_DIRTY )
{
Expand Down Expand Up @@ -2366,9 +2359,7 @@ int CNetChan::ProcessPacketHeader( netpacket_t * packet )
else if ( subchan->state == SUBCHANNEL_DIRTY )
{
// remote host lost dirty channel data, flip bit back
int bit = 1<<subchan->index; // flip bit back since data was send yet

FLIPBIT(m_nOutReliableState, bit);
m_nOutReliableState.Flip(subchan->index);

subchan->Free();
}
Expand Down Expand Up @@ -2447,9 +2438,8 @@ void CNetChan::ProcessPacket( netpacket_t * packet, bool bHasHeader )

if ( flags & PACKET_FLAG_RELIABLE )
{
int i, bit = 1<<msg.ReadUBitLong( 3 );

for ( i=0; i<MAX_STREAMS; i++ )
int subChannelIndex = msg.ReadUBitLong( SUBCHANNEL_BITS );
for ( int i=0; i<MAX_STREAMS; i++ )
{
if ( msg.ReadOneBit() != 0 )
{
Expand All @@ -2459,9 +2449,9 @@ void CNetChan::ProcessPacket( netpacket_t * packet, bool bHasHeader )
}

// flip subChannel bit to signal successful receiving
FLIPBIT(m_nInReliableState, bit);
m_nInReliableState.Flip(subChannelIndex);

for ( i=0; i<MAX_STREAMS; i++ )
for ( int i=0; i<MAX_STREAMS; i++ )
{
if ( !CheckReceivingList( i ) )
return; // error while processing
Expand Down
8 changes: 5 additions & 3 deletions engine/net_chan.h
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Original file line number Diff line number Diff line change
Expand Up @@ -20,6 +20,7 @@
#include "tier1/utlbuffer.h"
#include "const.h"
#include "inetchannel.h"
#include "bitvec.h"

// How fast to converge flow estimates
#define FLOW_AVG ( 3.0F / 4.0F )
Expand All @@ -29,7 +30,8 @@

#define NET_FRAMES_BACKUP 64 // must be power of 2
#define NET_FRAMES_MASK (NET_FRAMES_BACKUP-1)
#define MAX_SUBCHANNELS 8 // we have 8 alternative send&wait bits
constexpr int MAX_SUBCHANNELS = 8; // we have x alternative send&wait channels
constexpr int SUBCHANNEL_BITS = RequiredBits(MAX_SUBCHANNELS);

#define SUBCHANNEL_FREE 0 // subchannel is free to use
#define SUBCHANNEL_TOSEND 1 // subchannel has data, but not send yet
Expand Down Expand Up @@ -266,9 +268,9 @@ class CNetChan : public INetChannel
int m_nOutSequenceNrAck;

// state of outgoing reliable data (0/1) flip flop used for loss detection
int m_nOutReliableState;
CBitVec<MAX_SUBCHANNELS> m_nOutReliableState; // RaphaelIT7: Changed to use a CBitVec to allow easy changing of MAX_SUBCHANNELS
// state of incoming reliable data
int m_nInReliableState;
CBitVec<MAX_SUBCHANNELS> m_nInReliableState; // RaphaelIT7: Changed to use a CBitVec to allow easy changing of MAX_SUBCHANNELS

int m_nChokedPackets; //number of choked packets

Expand Down
21 changes: 20 additions & 1 deletion public/bitvec.h
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Original file line number Diff line number Diff line change
Expand Up @@ -246,6 +246,7 @@ class CBitVecT : public BASE_OPS
void CopyTo(CBitVecT *out) const;
void Copy( const CBitVecT<BASE_OPS> &other, int nBits=-1 );
bool Compare( const CBitVecT<BASE_OPS> &other, int nBits=-1 ) const;
bool CompareBit( const CBitVecT<BASE_OPS> &other, int nBit ) const;

bool IsAllClear(void) const; // Are all bits zero?
bool IsAllSet(void) const; // Are all bits one?
Expand All @@ -254,7 +255,8 @@ class CBitVecT : public BASE_OPS
bool IsBitSet( int bitNum ) const;
void Set( int bitNum );
void Set( int bitNum, bool bNewVal );
void Clear(int bitNum);
void Clear( int bitNum );
void Flip( int bitNum );

bool TestAndSet(int bitNum);

Expand Down Expand Up @@ -664,6 +666,14 @@ inline void CBitVecT<BASE_OPS>::Clear(int bitNum)
*pInt &= ~BitVec_Bit( bitNum );
}

template <class BASE_OPS>
inline void CBitVecT<BASE_OPS>::Flip(int bitNum)
{
Assert( bitNum >= 0 && bitNum < this->GetNumBits() );
uint32 *pInt = this->Base() + BitVec_Int( bitNum );
*pInt ^= BitVec_Bit(bitNum);
}

//-----------------------------------------------------------------------------

template <class BASE_OPS>
Expand Down Expand Up @@ -917,6 +927,15 @@ inline bool CBitVecT<BASE_OPS>::Compare( const CBitVecT<BASE_OPS> &other, int nB
return ( memcmp( this->Base(), other.Base(), nBytes ) == 0 );
}

template <class BASE_OPS>
inline bool CBitVecT<BASE_OPS>::CompareBit(const CBitVecT<BASE_OPS> &other, int bitNum) const
{
Assert(bitNum >= 0 && bitNum < this->GetNumBits());

return (this->Base()[BitVec_Int(bitNum)] & BitVec_Bit(bitNum)) ==
(other.Base()[BitVec_Int(bitNum)] & BitVec_Bit(bitNum));
}

//-----------------------------------------------------------------------------
template <class BASE_OPS>
inline uint32 CBitVecT<BASE_OPS>::GetDWord(int i) const
Expand Down
10 changes: 10 additions & 0 deletions public/const.h
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Original file line number Diff line number Diff line change
Expand Up @@ -12,6 +12,16 @@
#pragma once
#endif

// RaphaelIT7: log function for constexpr numbers - mainly used to figure out how many bits for networking are needed for a limit
constexpr int RequiredBits(int v)
{
int bits = 0;
while ((1 << bits) < v)
++bits;

return bits;
}

// the command line param that tells the engine to use steam
#define STEAM_PARM "-steam"
// the command line param to tell dedicated server to restart
Expand Down
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