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/*
* InspIRCd -- Internet Relay Chat Daemon
*
* Copyright (C) 2013 Adam <Adam@anope.org>
*
* This file is part of InspIRCd. InspIRCd is free software: you can
* redistribute it and/or modify it under the terms of the GNU General Public
* License as published by the Free Software Foundation, version 2.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "inspircd.h"
#include "modules/dns.h"
namespace
{
LocalIntExt* dl;
LocalStringExt* ph;
}
/** Derived from Resolver, and performs user forward/reverse lookups.
*/
class UserResolver : public DNS::Request
{
/** UUID we are looking up */
const std::string uuid;
/** True if the lookup is forward, false if is a reverse lookup
*/
const bool fwd;
public:
/** Create a resolver.
* @param mgr DNS Manager
* @param me this module
* @param user The user to begin lookup on
* @param to_resolve The IP or host to resolve
* @param qt The query type
*/
UserResolver(DNS::Manager* mgr, Module* me, LocalUser* user, const std::string& to_resolve, DNS::QueryType qt)
: DNS::Request(mgr, me, to_resolve, qt)
, uuid(user->uuid)
, fwd(qt == DNS::QUERY_A || qt == DNS::QUERY_AAAA)
{
}
/** Called on successful lookup
* if a previous result has already come back.
* @param r The finished query
*/
void OnLookupComplete(const DNS::Query* r)
{
LocalUser* bound_user = (LocalUser*)ServerInstance->FindUUID(uuid);
if (!bound_user)
{
ServerInstance->Logs->Log("RESOLVER", LOG_DEBUG, "Resolution finished for user '%s' who is gone", uuid.c_str());
return;
}
const DNS::ResourceRecord& ans_record = r->answers[0];
ServerInstance->Logs->Log("RESOLVER", LOG_DEBUG, "DNS result for %s: '%s' -> '%s'", uuid.c_str(), ans_record.name.c_str(), ans_record.rdata.c_str());
if (!fwd)
{
// first half of resolution is done. We now need to verify that the host matches.
ph->set(bound_user, ans_record.rdata);
UserResolver* res_forward;
if (bound_user->client_sa.sa.sa_family == AF_INET6)
{
/* IPV6 forward lookup */
res_forward = new UserResolver(this->manager, this->creator, bound_user, ans_record.rdata, DNS::QUERY_AAAA);
}
else
{
/* IPV4 lookup */
res_forward = new UserResolver(this->manager, this->creator, bound_user, ans_record.rdata, DNS::QUERY_A);
}
try
{
this->manager->Process(res_forward);
}
catch (DNS::Exception& e)
{
delete res_forward;
ServerInstance->Logs->Log("RESOLVER", LOG_DEBUG, "Error in resolver: %s",e.GetReason());
bound_user->WriteNotice("*** There was an internal error resolving your host, using your IP address (" + bound_user->GetIPString() + ") instead.");
dl->set(bound_user, 0);
}
}
else
{
/* Both lookups completed */
irc::sockets::sockaddrs* user_ip = &bound_user->client_sa;
bool rev_match = false;
if (user_ip->sa.sa_family == AF_INET6)
{
struct in6_addr res_bin;
if (inet_pton(AF_INET6, ans_record.rdata.c_str(), &res_bin))
{
rev_match = !memcmp(&user_ip->in6.sin6_addr, &res_bin, sizeof(res_bin));
}
}
else
{
struct in_addr res_bin;
if (inet_pton(AF_INET, ans_record.rdata.c_str(), &res_bin))
{
rev_match = !memcmp(&user_ip->in4.sin_addr, &res_bin, sizeof(res_bin));
}
}
dl->set(bound_user, 0);
if (rev_match)
{
std::string* hostname = ph->get(bound_user);
if (hostname == NULL)
{
ServerInstance->Logs->Log("RESOLVER", LOG_DEFAULT, "ERROR: User has no hostname attached when doing a forward lookup");
bound_user->WriteNotice("*** There was an internal error resolving your host, using your IP address (" + bound_user->GetIPString() + ") instead.");
return;
}
else if (hostname->length() < 65)
{
/* Hostnames starting with : are not a good thing (tm) */
if ((*hostname)[0] == ':')
hostname->insert(0, "0");
bound_user->WriteNotice("*** Found your hostname (" + *hostname + (r->cached ? ") -- cached" : ")"));
bound_user->host.assign(*hostname, 0, 64);
bound_user->dhost = bound_user->host;
/* Invalidate cache */
bound_user->InvalidateCache();
}
else
{
bound_user->WriteNotice("*** Your hostname is longer than the maximum of 64 characters, using your IP address (" + bound_user->GetIPString() + ") instead.");
}
ph->unset(bound_user);
}
else
{
bound_user->WriteNotice("*** Your hostname does not match up with your IP address. Sorry, using your IP address (" + bound_user->GetIPString() + ") instead.");
}
}
}
/** Called on failed lookup
* @param query The errored query
*/
void OnError(const DNS::Query* query)
{
LocalUser* bound_user = (LocalUser*)ServerInstance->FindUUID(uuid);
if (bound_user)
{
bound_user->WriteNotice("*** Could not resolve your hostname: " + this->manager->GetErrorStr(query->error) + "; using your IP address (" + bound_user->GetIPString() + ") instead.");
dl->set(bound_user, 0);
ServerInstance->stats->statsDnsBad++;
}
}
};
class ModuleHostnameLookup : public Module
{
LocalIntExt dnsLookup;
LocalStringExt ptrHosts;
dynamic_reference<DNS::Manager> DNS;
public:
ModuleHostnameLookup()
: dnsLookup("dnsLookup", this)
, ptrHosts("ptrHosts", this)
, DNS(this, "DNS")
{
dl = &dnsLookup;
ph = &ptrHosts;
}
void init()
{
OnRehash(NULL);
ServerInstance->Modules->AddService(this->dnsLookup);
ServerInstance->Modules->AddService(this->ptrHosts);
Implementation i[] = { I_OnUserInit, I_OnCheckReady };
ServerInstance->Modules->Attach(i, this, sizeof(i) / sizeof(Implementation));
}
void OnUserInit(LocalUser *user)
{
if (!DNS || user->MyClass->nouserdns)
{
user->WriteNotice("*** Skipping host resolution (disabled by server administrator)");
return;
}
user->WriteNotice("*** Looking up your hostname...");
UserResolver* res_reverse = new UserResolver(*this->DNS, this, user, user->GetIPString(), DNS::QUERY_PTR);
try
{
/* If both the reverse and forward queries are cached, the user will be able to pass DNS completely
* before Process() completes, which is why dnsLookup.set() is here, before Process()
*/
this->dnsLookup.set(user, 1);
this->DNS->Process(res_reverse);
}
catch (DNS::Exception& e)
{
this->dnsLookup.set(user, 0);
delete res_reverse;
ServerInstance->Logs->Log("USERS", LOG_DEBUG, "Error in resolver: %s", e.GetReason());
ServerInstance->stats->statsDnsBad++;
}
}
ModResult OnCheckReady(LocalUser* user)
{
return this->dnsLookup.get(user) ? MOD_RES_DENY : MOD_RES_PASSTHRU;
}
Version GetVersion()
{
return Version("Provides support for DNS lookups on connecting clients", VF_CORE|VF_VENDOR);
}
};
MODULE_INIT(ModuleHostnameLookup)
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