Counter Strike : Global Offensive Source Code
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//========= Copyright © 1996-2005, Valve Corporation, All rights reserved. ============//
//
// Purpose: Handles all the functions for implementing remote access to the engine
//
//=============================================================================//
#include "netadr.h"
#include "sv_ipratelimit.h"
#include "convar.h"
#include "utlrbtree.h"
#include "utlvector.h"
#include "utlmap.h"
#include "../gcsdk/steamextra/tier1/utlhashmaplarge.h"
#include "filesystem.h"
#include "sv_log.h"
#include "tier1/ns_address.h"
// NOTE: This has to be the last file included!
#include "tier0/memdbgon.h"
static ConVar sv_max_queries_sec( "sv_max_queries_sec", "10.0", FCVAR_RELEASE, "Maximum queries per second to respond to from a single IP address." );
static ConVar sv_max_queries_window( "sv_max_queries_window", "30", FCVAR_RELEASE, "Window over which to average queries per second averages." );
static ConVar sv_max_queries_tracked_ips_max( "sv_max_queries_tracked_ips_max", "50000", FCVAR_RELEASE, "Window over which to average queries per second averages." );
static ConVar sv_max_queries_tracked_ips_prune( "sv_max_queries_tracked_ips_prune", "10", FCVAR_RELEASE, "Window over which to average queries per second averages." );
static ConVar sv_max_queries_sec_global( "sv_max_queries_sec_global", "500", FCVAR_RELEASE, "Maximum queries per second to respond to from anywhere." );
static ConVar sv_logblocks("sv_logblocks", "0", FCVAR_RELEASE, "If true when log when a query is blocked (can cause very large log files)");
class CIPRateLimit
{
public:
CIPRateLimit();
~CIPRateLimit();
// updates an ip entry, return true if the ip is allowed, false otherwise
bool CheckIP( netadr_t ip );
void Reset()
{
m_IPTimes.RemoveAll();
m_IPStorage.RemoveAll();
m_iGlobalCount = 0;
m_lLastTime = -1;
m_lLastDistributedDetection = -1;
m_lLastPersonalDetection = -1;
}
private:
typedef int ip_t;
struct iprate_val
{
long lastTime;
int count;
int32 idxiptime;
};
struct IpHashNoopFunctor
{
typedef uint32 TargetType;
TargetType operator()( const ip_t &key ) const
{
return key;
}
};
typedef CUtlHashMapLarge< ip_t, iprate_val, CDefEquals< ip_t >, IpHashNoopFunctor > IPStorage_t;
IPStorage_t m_IPStorage;
typedef CUtlMap< long, ip_t, int32, CDefLess< long > > IPTimes_t;
IPTimes_t m_IPTimes;
int m_iGlobalCount;
long m_lLastTime;
long m_lLastDistributedDetection;
long m_lLastPersonalDetection;
};
static CIPRateLimit rateChecker;
//-----------------------------------------------------------------------------
// Purpose: return false if this IP exceeds rate limits
//-----------------------------------------------------------------------------
bool CheckConnectionLessRateLimits( const ns_address &adr )
{
if ( !adr.IsType< netadr_t >() )
return true;
// This function can be called from socket thread, mutex around it
static CThreadMutex s_mtx;
AUTO_LOCK( s_mtx );
bool ret = rateChecker.CheckIP( adr.AsType<netadr_t>() );
if ( !ret && sv_logblocks.GetBool() == true )
{
g_Log.Printf("Traffic from %s was blocked for exceeding rate limits\n", ns_address_render( adr ).String() );
}
return ret;
}
//-----------------------------------------------------------------------------
// Purpose: Constructor
//-----------------------------------------------------------------------------
CIPRateLimit::CIPRateLimit()
{
m_iGlobalCount = 0;
m_lLastTime = -1;
m_lLastDistributedDetection = -1;
m_lLastPersonalDetection = -1;
}
//-----------------------------------------------------------------------------
// Purpose: Destructor
//-----------------------------------------------------------------------------
CIPRateLimit::~CIPRateLimit()
{
}
//-----------------------------------------------------------------------------
// Purpose: return false if this IP has exceeded limits
//-----------------------------------------------------------------------------
bool CIPRateLimit::CheckIP( netadr_t adr )
{
long curTime = (long)Plat_FloatTime();
// check the per ip rate (do this first, so one person dosing doesn't add to the global max rate
ip_t clientIP;
memcpy( &clientIP, adr.ip, sizeof(ip_t) );
int const MAX_TREE_SIZE = sv_max_queries_tracked_ips_max.GetInt();
int const MAX_TREE_PRUNE = sv_max_queries_tracked_ips_prune.GetInt();
// Prune some elements from the tree
int numPruned = 0;
for ( int32 itIPTime = m_IPTimes.FirstInorder(); ( itIPTime != m_IPTimes.InvalidIndex() ); )
{
int32 itIPTimeNext = m_IPTimes.NextInorder( itIPTime );
ip_t ipTracked = m_IPTimes.Element( itIPTime );
if ( ipTracked != clientIP )
{
if ( ( curTime - m_IPTimes.Key( itIPTime ) ) < sv_max_queries_window.GetFloat() )
break; // need to still keep monitoring this IP address, time is in order so next ones are even more recent
m_IPStorage.Remove( ipTracked );
m_IPTimes.RemoveAt( itIPTime );
++ numPruned;
if ( ( numPruned >= MAX_TREE_PRUNE ) && ( m_IPStorage.Count() < MAX_TREE_SIZE ) )
break;
}
itIPTime = itIPTimeNext;
}
if ( m_IPStorage.Count() > MAX_TREE_SIZE )
{
// This looks like we are under distributed attack where we are seeing a
// very large number of IP addresses in a short time period
// Stop tracking individual IP addresses and turn on global rate limit
Msg( "IP rate limit detected distributed packet load (%u buckets, %u global count).\n", m_IPStorage.Count(), m_iGlobalCount );
Reset();
m_iGlobalCount = MAX( 1, ( sv_max_queries_sec_global.GetFloat() + 1 ) * ( sv_max_queries_window.GetFloat() + 1 ) );
m_lLastTime = curTime;
m_lLastDistributedDetection = curTime;
}
// now find the entry and check if it's within our rate limits
bool bPerIpLimitingPerformed = false;
IPStorage_t::IndexType_t ipEntry = m_IPStorage.Find( clientIP );
if ( m_IPStorage.IsValidIndex( ipEntry ) )
{
bPerIpLimitingPerformed = true;
iprate_val &iprateval = m_IPStorage.Element( ipEntry );
if ( ( curTime - iprateval.lastTime ) > sv_max_queries_window.GetFloat() )
{
float query_rate = static_cast< float >( iprateval.count ) / sv_max_queries_window.GetFloat(); // add one so the bottom is never zero
if ( query_rate > sv_max_queries_sec.GetFloat() )
{
if ( ( curTime - m_lLastPersonalDetection ) > sv_max_queries_window.GetFloat()/10 )
{
Msg( "IP rate limiting client %s sustained %u hits at %.1f pps (%u buckets, %u global count).\n", adr.ToString(), iprateval.count, query_rate, m_IPStorage.Count(), m_iGlobalCount );
}
}
m_IPTimes.RemoveAt( iprateval.idxiptime );
iprateval.idxiptime = m_IPTimes.Insert( curTime, clientIP );
iprateval.lastTime = curTime;
iprateval.count = 1;
}
else
{
++ iprateval.count;
float query_rate = static_cast< float >( iprateval.count ) / sv_max_queries_window.GetFloat(); // add one so the bottom is never zero
if ( query_rate > sv_max_queries_sec.GetFloat() )
{
if ( ( curTime - m_lLastPersonalDetection ) > sv_max_queries_window.GetFloat() )
{
m_lLastPersonalDetection = curTime;
Msg( "IP rate limiting client %s at %u hits (%u buckets, %u global count).\n", adr.ToString(), iprateval.count, m_IPStorage.Count(), m_iGlobalCount );
}
return false;
}
}
}
// now check the global rate
m_iGlobalCount++;
if( (curTime - m_lLastTime) > sv_max_queries_window.GetFloat() )
{
float query_rate = static_cast< float >( m_iGlobalCount ) / sv_max_queries_window.GetFloat(); // add one so the bottom is never zero
if ( query_rate > sv_max_queries_sec_global.GetFloat() )
{
if ( ( curTime - m_lLastDistributedDetection ) > sv_max_queries_window.GetFloat()/10 )
{
Msg( "IP rate limit sustained %u distributed packets at %.1f pps (%u buckets).\n", m_iGlobalCount, query_rate, m_IPStorage.Count() );
}
}
m_lLastTime = curTime;
m_iGlobalCount = 1;
}
else
{
float query_rate = static_cast<float>( m_iGlobalCount ) / sv_max_queries_window.GetFloat(); // add one so the bottom is never zero
if( query_rate > sv_max_queries_sec_global.GetFloat() )
{
if ( ( curTime - m_lLastDistributedDetection ) > sv_max_queries_window.GetFloat() )
{
m_lLastDistributedDetection = curTime;
Msg( "IP rate limit under distributed packet load (%u buckets, %u global count), rejecting %s.\n", m_IPStorage.Count(), m_iGlobalCount, adr.ToString() );
}
return false;
}
}
if ( !bPerIpLimitingPerformed )
{
iprate_val iprateval;
iprateval.count = 1;
iprateval.lastTime = curTime;
// not found, insert this new guy
iprateval.idxiptime = m_IPTimes.Insert( curTime, clientIP );
m_IPStorage.Insert( clientIP, iprateval );
}
return true;
}