source-engine-2018-hl2_src/networksystem/udp_process.cpp

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2020-04-23 00:56:21 +08:00
//========= Copyright Valve Corporation, All rights reserved. ============//
//
// Purpose:
//
//===========================================================================//
#include "tier1/utlbuffer.h"
#include "UDP_Socket.h"
#include "NetChannel.h"
#include "sm_protocol.h"
#include "networksystem.h"
//-----------------------------------------------------------------------------
// Allocates memory for packets
//-----------------------------------------------------------------------------
static CUtlMemoryPool s_PacketBufferAlloc( NET_MAX_MESSAGE, 8, CUtlMemoryPool::GROW_SLOW );
DEFINE_FIXEDSIZE_ALLOCATOR( CNetPacket, 32, CUtlMemoryPool::GROW_SLOW );
//-----------------------------------------------------------------------------
// Constructor, destructor
//-----------------------------------------------------------------------------
CNetPacket::CNetPacket()
{
m_pData = reinterpret_cast<byte*>( s_PacketBufferAlloc.Alloc() );
m_nRefCount = 1;
}
CNetPacket::~CNetPacket()
{
s_PacketBufferAlloc.Free( m_pData );
}
void CNetPacket::AddRef()
{
++m_nRefCount;
}
void CNetPacket::Release()
{
if ( --m_nRefCount <= 0 )
{
delete this;
}
}
bool UDP_ReceiveDatagram( CUDPSocket *pSocket, CNetPacket* pPacket )
{
Assert( pPacket );
netadr_t packetFrom;
CUtlBuffer buf( pPacket->m_pData, NET_MAX_MESSAGE );
if ( pSocket->RecvFrom( packetFrom, buf ) )
{
pPacket->m_From = packetFrom;
pPacket->m_nSizeInBytes = buf.TellPut();
return true;
}
return false;
}
CNetPacket *UDP_GetPacket( CUDPSocket *pSocket )
{
CNetPacket *pPacket = new CNetPacket;
// setup new packet
pPacket->m_From.SetType( NA_IP );
pPacket->m_From.Clear();
pPacket->m_flReceivedTime = g_pNetworkSystemImp->GetTime();
pPacket->m_pSource = pSocket;
pPacket->m_nSizeInBytes = 0;
pPacket->m_Message.SetDebugName("inpacket.message");
// then check UDP data
if ( !UDP_ReceiveDatagram( pSocket, pPacket ) )
{
delete pPacket;
return NULL;
}
Assert( pPacket->m_nSizeInBytes );
// prepare bitbuffer for reading packet with new size
pPacket->m_Message.StartReading( pPacket->m_pData, pPacket->m_nSizeInBytes );
return pPacket;
}
void UDP_ProcessSocket( CUDPSocket *pSocket, IConnectionlessPacketHandler *pHandler, ILookupChannel *pLookup )
{
CNetPacket *pPacket;
Assert( pSocket );
// Get datagrams from sockets
while ( ( pPacket = UDP_GetPacket ( pSocket ) ) != NULL )
{
/*
if ( Filter_ShouldDiscard ( pPacket->m_From ) ) // filterning is done by network layer
{
Filter_SendBan( pPacket->m_From ); // tell them we aren't listening...
continue;
}
*/
// Find the netchan it came from
if ( *(unsigned int *)pPacket->m_pData == CONNECTIONLESS_HEADER )
{
g_pNetworkSystemImp->EnqueueConnectionlessNetworkPacket( pPacket, pHandler );
}
else
{
INetChannel *pNetChan = pLookup->FindNetChannel( pPacket->m_From );
g_pNetworkSystemImp->EnqueueNetworkPacket( pPacket, static_cast<CNetChannel*>( pNetChan ) );
}
}
}
void UDP_ProcessConnectionlessPacket( CNetPacket *pPacket, IConnectionlessPacketHandler *pHandler )
{
// check for connectionless packet (0xffffffff) first
Assert( *(unsigned int *)pPacket->m_pData == CONNECTIONLESS_HEADER );
pPacket->m_Message.ReadLong(); // read the -1
/*
if ( net_showudp.GetInt() )
{
Msg("UDP <- %s: sz=%i OOB '%c'\n", info.m_pPacket->m_From.ToString(), pPacket->m_nSizeInBytes, pPacket->m_pData[4] );
}
*/
pHandler->ProcessConnectionlessPacket( pPacket );
}