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engine: make Filter_ShouldDiscard threadsafe #160

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174 changes: 97 additions & 77 deletions engine/sv_filter.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -26,6 +26,11 @@ static ConVar sv_filterban( "sv_filterban", "1", 0, "Set packet filtering by IP

CUtlVector< ipfilter_t > g_IPFilters;
CUtlVector< userfilter_t > g_UserFilters;
#if defined(WIN32) || defined(_WIN32)
CThreadSpinRWLock g_IPFilterMutex;
#else
CThreadRWLock g_IPFilterMutex;
#endif

#define BANNED_IP_FILENAME "banned_ip.cfg"
#define BANNED_USER_FILENAME "banned_user.cfg"
Expand All @@ -45,6 +50,7 @@ void Filter_SendBan( const netadr_t& adr )
// Purpose: Checks an IP address to see if it is banned
// Input : *adr -
// Output : bool
// RaphaelIT7: This function is fully threadsafe in case the network layer gets threaded
//-----------------------------------------------------------------------------
bool Filter_ShouldDiscard( const netadr_t& adr )
{
Expand All @@ -57,6 +63,8 @@ bool Filter_ShouldDiscard( const netadr_t& adr )

unsigned in = *(unsigned *)&adr.ip[0];

AUTO_LOCK_READ( g_IPFilterMutex );

// Handle timeouts
for ( intp i = g_IPFilters.Count() - 1 ; i >= 0 ; i--)
{
Expand Down Expand Up @@ -176,41 +184,47 @@ static void Filter_Add_f( const CCommand& args )
return;

intp i;
for (i=0 ; i<g_IPFilters.Count(); i++)
{
if ( g_IPFilters[i].compare == 0xffffffff ||
( g_IPFilters[i].compare == f.compare && g_IPFilters[i].mask == f.mask ) )
break; // free spot
}

if (i == g_IPFilters.Count())
{
if (g_IPFilters.Count() == MAX_IPFILTERS)
{ // Scoped due to a possible dead lock since Filter_ShouldDiscard further down locks for read
AUTO_LOCK_WRITE( g_IPFilterMutex );
g_IPFilterMutex.LockForWrite();

for (i=0 ; i<g_IPFilters.Count(); i++)
{
ConMsg( "addip: IP filter list is full (max %zd).\n", MAX_IPFILTERS );
return;
if ( g_IPFilters[i].compare == 0xffffffff ||
( g_IPFilters[i].compare == f.compare && g_IPFilters[i].mask == f.mask ) )
break; // free spot
}

if (i == g_IPFilters.Count())
{
if (g_IPFilters.Count() == MAX_IPFILTERS)
{
ConMsg( "addip: IP filter list is full (max %zd).\n", MAX_IPFILTERS );
g_IPFilterMutex.UnlockWrite();
return;
}

i = g_IPFilters.AddToTail();
}
else
{
// updating in-place, so don't kick people
bKick = false;
}
i = g_IPFilters.AddToTail();
}
else
{
// updating in-place, so don't kick people
bKick = false;
}

if (banTime < 0.01)
{
banTime = 0.0;
}
if (banTime < 0.01)
{
banTime = 0.0;
}

g_IPFilters[i].banTime = banTime;
// Time to unban.
g_IPFilters[i].banEndTime = ( banTime != 0.0 ) ? ( realtime + 60.0 * banTime ) : 0.0;
g_IPFilters[i].banTime = banTime;
// Time to unban.
g_IPFilters[i].banEndTime = ( banTime != 0.0 ) ? ( realtime + 60.0 * banTime ) : 0.0;

if ( !Filter_ConvertString( args[2], &g_IPFilters[i]) )
{
g_IPFilters[i].compare = 0xffffffff;
if ( !Filter_ConvertString( args[2], &g_IPFilters[i]) )
{
g_IPFilters[i].compare = 0xffffffff;
}
}

if ( bKick )
Expand Down Expand Up @@ -291,70 +305,73 @@ CON_COMMAND( removeip, "Remove an IP address from the ban list." )
return;
}

// if no "." in the string we'll assume it's a slot number
if ( !V_strstr( args[1], "." ) )
const char *arg = args[1];
bool removed = false;
char removedIP[32] = {0};
const char *eventIP = nullptr;

// RaphaelIT7: We scope it due to my preference to have it unlocked when firing the gameevent
// to avoid any potential deadlocks if any code may add a filter inside the gameevent.
{
int slot = V_atoi( args[1] );
if ( slot <= 0 || slot > g_IPFilters.Count() )
AUTO_LOCK_WRITE( g_IPFilterMutex );

// if no "." in the string we'll assume it's a slot number
if ( !V_strstr( args[1], "." ) )
{
ConMsg( "removeip: Invalid slot %i\n", slot );
return;
}
int slot = V_atoi( args[1] );
if ( slot <= 0 || slot > g_IPFilters.Count() )
{
ConMsg( "removeip: Invalid slot %i\n", slot );
return;
}

// array access is zero based
byte b[4];
memcpy( b, &g_IPFilters[--slot].compare, sizeof(b) );
// array access is zero based
byte b[4];
memcpy( b, &g_IPFilters[--slot].compare, sizeof(b) );

g_IPFilters.Remove( slot );
g_IPFilters.Remove( slot );

char szIP[32];
V_sprintf_safe( szIP, "%i.%i.%i.%i", b[0], b[1], b[2], b[3] );
// Tell server operator
ConMsg( "removeip: Filter removed for %s, IP %s\n", args[1], szIP );
V_sprintf_safe( removedIP, "%i.%i.%i.%i", b[0], b[1], b[2], b[3] );

// send an event
IGameEvent *event = g_GameEventManager.CreateEvent( "server_removeban" );
if ( event )
{
event->SetString( "networkid", "" );
event->SetString( "ip", szIP );
event->SetString( "by", ( cmd_source == src_command ) ? "Console" : host_client->m_Name );

g_GameEventManager.FireEvent( event );
removed = true;
eventIP = removedIP;
return;
}

return;
}

ipfilter_t f;
if ( !Filter_ConvertString( args[1], &f ) )
return;
ipfilter_t f;
if ( !Filter_ConvertString( args[1], &f ) )
return;

for ( intp i = 0 ; i < g_IPFilters.Count() ; i++ )
{
if ( ( g_IPFilters[i].mask == f.mask ) &&
( g_IPFilters[i].compare == f.compare ) )
for ( intp i = 0 ; i < g_IPFilters.Count() ; i++ )
{
g_IPFilters.Remove(i);

ConMsg( "removeip: filter removed for %s\n", args[1] );

// send an event
IGameEvent *event = g_GameEventManager.CreateEvent( "server_removeban" );
if ( event )
if ( ( g_IPFilters[i].mask == f.mask ) &&
( g_IPFilters[i].compare == f.compare ) )
{
event->SetString( "networkid", "" );
event->SetString( "ip", args[1] );
event->SetString( "by", ( cmd_source == src_command ) ? "Console" : host_client->m_Name );
g_IPFilters.Remove(i);

g_GameEventManager.FireEvent( event );
removed = true;
eventIP = arg;
break;
}

return;
}
}

ConMsg( "removeip: Couldn't find %s\n", args[1] );
if ( !removed )
{
ConMsg( "removeip: Couldn't find %s\n", arg );
return;
}

ConMsg( "removeip: Filter removed for %s\n", eventIP );

IGameEvent *event = g_GameEventManager.CreateEvent( "server_removeban" );
if ( event )
{
event->SetString( "networkid", "" );
event->SetString( "ip", eventIP );
event->SetString( "by", ( cmd_source == src_command ) ? "Console" : host_client->m_Name );
g_GameEventManager.FireEvent( event );
}
}


Expand All @@ -363,6 +380,7 @@ CON_COMMAND( removeip, "Remove an IP address from the ban list." )
//-----------------------------------------------------------------------------
CON_COMMAND( listip, "List IP addresses on the ban list." )
{
AUTO_LOCK_READ( g_IPFilterMutex );
const intp count = g_IPFilters.Count();
if ( !count )
{
Expand Down Expand Up @@ -407,6 +425,8 @@ CON_COMMAND( writeip, "Save the ban list to " BANNED_IP_FILENAME "." )
return;
}

AUTO_LOCK_READ( g_IPFilterMutex );

byte b[4];
for ( const auto &ipf : g_IPFilters )
{
Expand Down
47 changes: 47 additions & 0 deletions public/tier0/threadtools.h
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Original file line number Diff line number Diff line change
Expand Up @@ -1237,6 +1237,53 @@ class PLATFORM_CLASS CThreadRWLock
int m_nPendingReaders{ 0 };
};

template <class RWLOCK_TYPE>
class CAutoReadLockT
{
public:
FORCEINLINE CAutoReadLockT(RWLOCK_TYPE &lock)
: m_lock(lock)
{
m_lock.LockForRead();
}

FORCEINLINE ~CAutoReadLockT()
{
m_lock.UnlockRead();
}

private:
RWLOCK_TYPE &m_lock;

CAutoReadLockT(const CAutoReadLockT &) = delete;
CAutoReadLockT &operator=(const CAutoReadLockT &) = delete;
};

template <class RWLOCK_TYPE>
class CAutoWriteLockT
{
public:
FORCEINLINE CAutoWriteLockT(RWLOCK_TYPE &lock)
: m_lock(lock)
{
m_lock.LockForWrite();
}

FORCEINLINE ~CAutoWriteLockT()
{
m_lock.UnlockWrite();
}

private:
RWLOCK_TYPE &m_lock;

CAutoWriteLockT(const CAutoWriteLockT &) = delete;
CAutoWriteLockT &operator=(const CAutoWriteLockT &) = delete;
};

#define AUTO_LOCK_READ(rwlock) CAutoReadLockT<decltype(rwlock)> UNIQUE_ID(rwlock)
#define AUTO_LOCK_WRITE(rwlock) CAutoWriteLockT<decltype(rwlock)> UNIQUE_ID(rwlock)

//-----------------------------------------------------------------------------
//
// CThreadSpinRWLock
Expand Down