/*
* Stores outgoing request to avoid receiving invalid responses
*/
void Utils::trackOutgoingPacket(const string& ip, const AdcCommand& cmd)
{
Lock l(cs);
uint64_t now = GET_TICK();
switch(cmd.getCommand())
{
// request packets
case AdcCommand::CMD_SCH:
case AdcCommand::CMD_PUB:
case AdcCommand::CMD_INF:
case AdcCommand::CMD_CTM:
case AdcCommand::CMD_GET:
case AdcCommand::CMD_PSR:
OutPacket p = { ip, now, cmd.getCommand() };
sentPackets.push_back(p);
break;
}
// clean up old items
// list is sorted by time, so the first unmatched item can break the loop
while(!sentPackets.empty())
{
uint64_t diff = now - sentPackets.front().time;
if(diff >= TIME_FOR_RESPONSE)
sentPackets.pop_front();
else
break;
}
}
/*
* General flooding protection
*/
bool Utils::checkFlood(const string& ip, const AdcCommand& cmd)
{
// ignore empty commands
if(cmd.getParameters().empty())
return false;
// there maximum allowed request packets from one IP per minute
// response packets are allowed only if request has been sent to the IP address
size_t maxAllowedPacketsPerMinute = 0;
uint32_t requestCmd = AdcCommand::CMD_SCH;
switch(cmd.getCommand())
{
// request packets
case AdcCommand::CMD_SCH: maxAllowedPacketsPerMinute = 20; break;
case AdcCommand::CMD_PUB: maxAllowedPacketsPerMinute = 10; break;
case AdcCommand::CMD_INF: maxAllowedPacketsPerMinute = 3; break;
case AdcCommand::CMD_CTM: maxAllowedPacketsPerMinute = 2; break;
case AdcCommand::CMD_RCM: maxAllowedPacketsPerMinute = 2; break;
case AdcCommand::CMD_GET: maxAllowedPacketsPerMinute = 2; break;
case AdcCommand::CMD_PSR: maxAllowedPacketsPerMinute = 3; break;
// response packets
case AdcCommand::CMD_STA:
return true; // STA can be response for more commands, but since it is for informative purposes only, there shouldn't be no way to abuse it
case AdcCommand::CMD_SND: requestCmd = AdcCommand::CMD_GET;
case AdcCommand::CMD_RES: // default value of requestCmd
Lock l(cs);
for(std::list<OutPacket>::iterator i = sentPackets.begin(); i != sentPackets.end(); i++)
{
if(i->cmd == requestCmd && i->ip == ip)
{
sentPackets.erase(i);
return true;
}
}
dcdebug("Received unwanted response from %s. Packet dropped.\n", ip.c_str());
return false;
}
Lock l(cs);
std::unordered_multiset<uint32_t>& packetsPerIp = receivedPackets[ip];
packetsPerIp.insert(cmd.getCommand());
if(packetsPerIp.count(cmd.getCommand()) > maxAllowedPacketsPerMinute)
{
dcdebug("Request flood detected (%d) from %s. Packet dropped.\n", packetsPerIp.count(cmd.getCommand()), ip.c_str());
return false;
}
return true;
}