#pragma comment(lib, "Iphlpapi.lib")
#endif
+namespace DNS
+{
+ /** Maximum value of a dns request id, 16 bits wide, 0xFFFF.
+ */
+ const unsigned int MAX_REQUEST_ID = 0xFFFF;
+}
+
using namespace DNS;
/** A full packet sent or recieved to/from the nameserver
irc::sockets::sockaddrs myserver;
+ /** Maximum number of entries in cache
+ */
+ static const unsigned int MAX_CACHE_SIZE = 1000;
+
static bool IsExpired(const Query& record, time_t now = ServerInstance->Time())
{
const ResourceRecord& req = record.answers[0];
*/
void AddCache(Query& r)
{
- const ResourceRecord& rr = r.answers[0];
+ if (cache.size() >= MAX_CACHE_SIZE)
+ cache.clear();
+
+ // Determine the lowest TTL value and use that as the TTL of the cache entry
+ unsigned int cachettl = UINT_MAX;
+ for (std::vector<ResourceRecord>::const_iterator i = r.answers.begin(); i != r.answers.end(); ++i)
+ {
+ const ResourceRecord& rr = *i;
+ if (rr.ttl < cachettl)
+ cachettl = rr.ttl;
+ }
+
+ cachettl = std::min(cachettl, (unsigned int)5*60);
+ ResourceRecord& rr = r.answers.front();
+ // Set TTL to what we've determined to be the lowest
+ rr.ttl = cachettl;
ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "cache: added cache for " + rr.name + " -> " + rr.rdata + " ttl: " + ConvToStr(rr.ttl));
this->cache[r.question] = r;
}
public:
DNS::Request* requests[MAX_REQUEST_ID+1];
- MyManager(Module* c) : Manager(c), Timer(3600, true)
+ MyManager(Module* c) : Manager(c), Timer(5*60, true)
{
for (unsigned int i = 0; i <= MAX_REQUEST_ID; ++i)
requests[i] = NULL;
if (SocketEngine::SendTo(this, buffer, len, 0, &this->myserver.sa, this->myserver.sa_size()) != len)
throw Exception("DNS: Unable to send query");
+
+ // Add timer for timeout
+ ServerInstance->Timers.AddTimer(req);
}
void RemoveRequest(DNS::Request* req)
{
- this->requests[req->id] = NULL;
+ if (requests[req->id] == req)
+ requests[req->id] = NULL;
}
std::string GetErrorStr(Error e)
case ERROR_NOT_AN_ANSWER:
case ERROR_NONSTANDARD_QUERY:
case ERROR_FORMAT_ERROR:
+ case ERROR_MALFORMED:
return "Malformed answer";
case ERROR_SERVER_FAILURE:
case ERROR_NOT_IMPLEMENTED:
}
Packet recv_packet;
+ bool valid = false;
try
{
recv_packet.Fill(buffer, length);
+ valid = true;
}
catch (Exception& ex)
{
ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, ex.GetReason());
- return;
}
+ // recv_packet.id must be filled in here
DNS::Request* request = this->requests[recv_packet.id];
if (request == NULL)
{
return;
}
- if (recv_packet.flags & QUERYFLAGS_OPCODE)
+ if (!valid)
+ {
+ ServerInstance->stats.DnsBad++;
+ recv_packet.error = ERROR_MALFORMED;
+ request->OnError(&recv_packet);
+ }
+ else if (recv_packet.flags & QUERYFLAGS_OPCODE)
{
ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "Received a nonstandard query");
ServerInstance->stats.DnsBad++;
recv_packet.error = ERROR_NONSTANDARD_QUERY;
request->OnError(&recv_packet);
}
- else if (recv_packet.flags & QUERYFLAGS_RCODE)
+ else if (!(recv_packet.flags & QUERYFLAGS_QR) || (recv_packet.flags & QUERYFLAGS_RCODE))
{
Error error = ERROR_UNKNOWN;
return true;
}
- void Rehash(const std::string& dnsserver)
+ void Rehash(const std::string& dnsserver, std::string sourceaddr, unsigned int sourceport)
{
if (this->GetFd() > -1)
{
SocketEngine::NonBlocking(s);
irc::sockets::sockaddrs bindto;
- memset(&bindto, 0, sizeof(bindto));
- bindto.sa.sa_family = myserver.sa.sa_family;
+ if (sourceaddr.empty())
+ {
+ // set a sourceaddr for irc::sockets::aptosa() based on the servers af type
+ if (myserver.sa.sa_family == AF_INET)
+ sourceaddr = "0.0.0.0";
+ else if (myserver.sa.sa_family == AF_INET6)
+ sourceaddr = "::";
+ }
+ irc::sockets::aptosa(sourceaddr, sourceport, bindto);
if (SocketEngine::Bind(this->GetFd(), bindto) < 0)
{
SocketEngine::Close(this->GetFd());
this->SetFd(-1);
}
+
+ if (bindto.sa.sa_family != myserver.sa.sa_family)
+ ServerInstance->Logs->Log(MODNAME, LOG_SPARSE, "Nameserver address family differs from source address family - hostnames might not resolve");
}
else
{
{
MyManager manager;
std::string DNSServer;
+ std::string SourceIP;
+ unsigned int SourcePort;
void FindDNSServer()
{
}
public:
- ModuleDNS() : manager(this)
+ ModuleDNS() : manager(this)
+ , SourcePort(0)
{
}
void ReadConfig(ConfigStatus& status) CXX11_OVERRIDE
{
std::string oldserver = DNSServer;
- DNSServer = ServerInstance->Config->ConfValue("dns")->getString("server");
+ const std::string oldip = SourceIP;
+ const unsigned int oldport = SourcePort;
+
+ ConfigTag* tag = ServerInstance->Config->ConfValue("dns");
+ DNSServer = tag->getString("server");
+ SourceIP = tag->getString("sourceip");
+ SourcePort = tag->getInt("sourceport", 0, 0, 65535);
+
if (DNSServer.empty())
FindDNSServer();
- if (oldserver != DNSServer)
- this->manager.Rehash(DNSServer);
+ if (oldserver != DNSServer || oldip != SourceIP || oldport != SourcePort)
+ this->manager.Rehash(DNSServer, SourceIP, SourcePort);
}
void OnUnloadModule(Module* mod)