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rec: Allow the use of a 'self-resolving' NS if cached A/AAAA exists #5937

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merged 1 commit into from Nov 10, 2017
Merged

rec: Allow the use of a 'self-resolving' NS if cached A/AAAA exists #5937

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67 changes: 63 additions & 4 deletions pdns/recursordist/test-syncres_cc.cc
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Open in desktop
Expand Up @@ -101,12 +101,17 @@ LuaConfigItems::LuaConfigItems()

static void init(bool debug=false)
{
L.setName("test");
L.disableSyslog(true);

if (debug) {
L.setName("test");
L.setLoglevel((Logger::Urgency)(6)); // info and up
L.disableSyslog(true);
L.toConsole(Logger::Info);
}
else {
L.setLoglevel(Logger::None);
L.toConsole(Logger::Error);
}

seedRandom("/dev/urandom");
reportAllTypes();
Expand Down Expand Up @@ -775,7 +780,7 @@ BOOST_AUTO_TEST_CASE(test_all_nss_network_error) {
}
else {
downServers.insert(ip);
return -1;
return 0;
}
});

Expand All @@ -791,10 +796,64 @@ BOOST_AUTO_TEST_CASE(test_all_nss_network_error) {
for (const auto& server : downServers) {
BOOST_CHECK_EQUAL(SyncRes::getServerFailsCount(server), 1);
BOOST_CHECK(SyncRes::isThrottled(time(nullptr), server, target, QType::A));
;
}
}

BOOST_AUTO_TEST_CASE(test_only_one_ns_up_resolving_itself_with_glue) {
std::unique_ptr<SyncRes> sr;
initSR(sr);

primeHints();

DNSName target("www.powerdns.com.");

sr->setAsyncCallback([target](const ComboAddress& ip, const DNSName& domain, int type, bool doTCP, bool sendRDQuery, int EDNS0Level, struct timeval* now, boost::optional<Netmask>& srcmask, boost::optional<const ResolveContext&> context, std::shared_ptr<RemoteLogger> outgoingLogger, LWResult* res) {

if (isRootServer(ip)) {
setLWResult(res, 0, false, false, true);
if (domain == target) {
addRecordToLW(res, "powerdns.com.", QType::NS, "pdns-public-ns1.powerdns.com.", DNSResourceRecord::AUTHORITY, 172800);
addRecordToLW(res, "powerdns.com.", QType::NS, "pdns-public-ns2.powerdns.net.", DNSResourceRecord::AUTHORITY, 172800);
addRecordToLW(res, "pdns-public-ns1.powerdns.com.", QType::A, "192.0.2.2", DNSResourceRecord::ADDITIONAL, 172800);
addRecordToLW(res, "pdns-public-ns1.powerdns.com.", QType::AAAA, "2001:DB8::2", DNSResourceRecord::ADDITIONAL, 172800);
}
else if (domain == DNSName("pdns-public-ns2.powerdns.net.")) {
addRecordToLW(res, "powerdns.net.", QType::NS, "pdns-public-ns2.powerdns.net.", DNSResourceRecord::AUTHORITY, 172800);
addRecordToLW(res, "powerdns.net.", QType::NS, "pdns-public-ns1.powerdns.com.", DNSResourceRecord::AUTHORITY, 172800);
addRecordToLW(res, "pdns-public-ns2.powerdns.net.", QType::A, "192.0.2.3", DNSResourceRecord::ADDITIONAL, 172800);
addRecordToLW(res, "pdns-public-ns2.powerdns.net.", QType::AAAA, "2001:DB8::3", DNSResourceRecord::ADDITIONAL, 172800);
}
return 1;
}
else if (ip == ComboAddress("192.0.2.3:53")) {
setLWResult(res, 0, true, false, true);
if (domain == DNSName("pdns-public-ns2.powerdns.net.")) {
if (type == QType::A) {
addRecordToLW(res, "pdns-public-ns2.powerdns.net.", QType::A, "192.0.2.3");
}
else if (type == QType::AAAA) {
addRecordToLW(res, "pdns-public-ns2.powerdns.net.", QType::AAAA, "2001:DB8::3");
}
}
else if (domain == target) {
if (type == QType::A) {
addRecordToLW(res, domain, QType::A, "192.0.2.1");
}
else if (type == QType::AAAA) {
addRecordToLW(res, domain, QType::AAAA, "2001:DB8::1");
}
}
return 1;
}
return 0;
});

vector<DNSRecord> ret;
int res = sr->beginResolve(target, QType(QType::A), QClass::IN, ret);
BOOST_CHECK_EQUAL(res, RCode::NoError);
BOOST_CHECK_EQUAL(ret.size(), 1);
}

BOOST_AUTO_TEST_CASE(test_os_limit_errors) {
std::unique_ptr<SyncRes> sr;
initSR(sr);
Expand Down
22 changes: 14 additions & 8 deletions pdns/syncres.cc
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Expand Up @@ -624,7 +624,7 @@ struct speedOrderCA

/** This function explicitly goes out for A or AAAA addresses
*/
vector<ComboAddress> SyncRes::getAddrs(const DNSName &qname, unsigned int depth, set<GetBestNSAnswer>& beenthere)
vector<ComboAddress> SyncRes::getAddrs(const DNSName &qname, unsigned int depth, set<GetBestNSAnswer>& beenthere, bool cacheOnly)
{
typedef vector<DNSRecord> res_t;
res_t res;
Expand All @@ -633,10 +633,12 @@ vector<ComboAddress> SyncRes::getAddrs(const DNSName &qname, unsigned int depth,
ret_t ret;

QType type;
bool oldCacheOnly = d_cacheonly;
bool oldRequireAuthData = d_requireAuthData;
bool oldValidationRequested = d_DNSSECValidationRequested;
d_requireAuthData = false;
d_DNSSECValidationRequested = false;
d_cacheonly = cacheOnly;

for(int j=1; j<2+s_doIPv6; j++)
{
Expand Down Expand Up @@ -685,6 +687,7 @@ vector<ComboAddress> SyncRes::getAddrs(const DNSName &qname, unsigned int depth,

d_requireAuthData = oldRequireAuthData;
d_DNSSECValidationRequested = oldValidationRequested;
d_cacheonly = oldCacheOnly;

/* we need to remove from the nsSpeeds collection the existing IPs
for this nameserver that are no longer in the set, even if there
Expand Down Expand Up @@ -1388,13 +1391,13 @@ bool SyncRes::nameserverIPBlockedByRPZ(const DNSFilterEngine& dfe, const ComboAd
return false;
}

vector<ComboAddress> SyncRes::retrieveAddressesForNS(const std::string& prefix, const DNSName& qname, vector<DNSName >::const_iterator& tns, const unsigned int depth, set<GetBestNSAnswer>& beenthere, const vector<DNSName >& rnameservers, NsSet& nameservers, bool& sendRDQuery, bool& pierceDontQuery, bool& flawedNSSet)
vector<ComboAddress> SyncRes::retrieveAddressesForNS(const std::string& prefix, const DNSName& qname, vector<DNSName >::const_iterator& tns, const unsigned int depth, set<GetBestNSAnswer>& beenthere, const vector<DNSName >& rnameservers, NsSet& nameservers, bool& sendRDQuery, bool& pierceDontQuery, bool& flawedNSSet, bool cacheOnly)
{
vector<ComboAddress> result;

if(!tns->empty()) {
LOG(prefix<<qname<<": Trying to resolve NS '"<<*tns<< "' ("<<1+tns-rnameservers.begin()<<"/"<<(unsigned int)rnameservers.size()<<")"<<endl);
result = getAddrs(*tns, depth+2, beenthere);
result = getAddrs(*tns, depth+2, beenthere, cacheOnly);
pierceDontQuery=false;
}
else {
Expand Down Expand Up @@ -2580,10 +2583,13 @@ int SyncRes::doResolveAt(NsSet &nameservers, DNSName auth, bool flawedNSSet, con
return -1;
}

// this line needs to identify the 'self-resolving' behaviour, but we get it wrong now
if(qname == *tns && qtype.getCode()==QType::A && rnameservers.size() > (size_t)(1+1*s_doIPv6)) {
LOG(prefix<<qname<<": Not using NS to resolve itself! ("<<(1+tns-rnameservers.cbegin())<<"/"<<rnameservers.size()<<")"<<endl);
continue;
bool cacheOnly = false;
// this line needs to identify the 'self-resolving' behaviour
if(qname == *tns && (qtype.getCode() == QType::A || qtype.getCode() == QType::AAAA)) {
/* we might have a glue entry in cache so let's try this NS
but only if we have enough in the cache to know how to reach it */
LOG(prefix<<qname<<": Using NS to resolve itself, but only using what we have in cache ("<<(1+tns-rnameservers.cbegin())<<"/"<<rnameservers.size()<<")"<<endl);
cacheOnly = true;
}

typedef vector<ComboAddress> remoteIPs_t;
Expand Down Expand Up @@ -2615,7 +2621,7 @@ int SyncRes::doResolveAt(NsSet &nameservers, DNSName auth, bool flawedNSSet, con
}
else {
/* if tns is empty, retrieveAddressesForNS() knows we have hardcoded servers (i.e. "forwards") */
remoteIPs = retrieveAddressesForNS(prefix, qname, tns, depth, beenthere, rnameservers, nameservers, sendRDQuery, pierceDontQuery, flawedNSSet);
remoteIPs = retrieveAddressesForNS(prefix, qname, tns, depth, beenthere, rnameservers, nameservers, sendRDQuery, pierceDontQuery, flawedNSSet, cacheOnly);

if(remoteIPs.empty()) {
LOG(prefix<<qname<<": Failed to get IP for NS "<<*tns<<", trying next if available"<<endl);
Expand Down
4 changes: 2 additions & 2 deletions pdns/syncres.hh
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Expand Up @@ -735,13 +735,13 @@ private:

inline vector<DNSName> shuffleInSpeedOrder(NsSet &nameservers, const string &prefix);
bool moreSpecificThan(const DNSName& a, const DNSName &b) const;
vector<ComboAddress> getAddrs(const DNSName &qname, unsigned int depth, set<GetBestNSAnswer>& beenthere);
vector<ComboAddress> getAddrs(const DNSName &qname, unsigned int depth, set<GetBestNSAnswer>& beenthere, bool cacheOnly);

bool nameserversBlockedByRPZ(const DNSFilterEngine& dfe, const NsSet& nameservers);
bool nameserverIPBlockedByRPZ(const DNSFilterEngine& dfe, const ComboAddress&);
bool throttledOrBlocked(const std::string& prefix, const ComboAddress& remoteIP, const DNSName& qname, const QType& qtype, bool pierceDontQuery);

vector<ComboAddress> retrieveAddressesForNS(const std::string& prefix, const DNSName& qname, vector<DNSName >::const_iterator& tns, const unsigned int depth, set<GetBestNSAnswer>& beenthere, const vector<DNSName >& rnameservers, NsSet& nameservers, bool& sendRDQuery, bool& pierceDontQuery, bool& flawedNSSet);
vector<ComboAddress> retrieveAddressesForNS(const std::string& prefix, const DNSName& qname, vector<DNSName >::const_iterator& tns, const unsigned int depth, set<GetBestNSAnswer>& beenthere, const vector<DNSName >& rnameservers, NsSet& nameservers, bool& sendRDQuery, bool& pierceDontQuery, bool& flawedNSSet, bool cacheOnly);
RCode::rcodes_ updateCacheFromRecords(unsigned int depth, LWResult& lwr, const DNSName& qname, const QType& qtype, const DNSName& auth, bool wasForwarded, const boost::optional<Netmask>, vState& state, bool& needWildcardProof);
bool processRecords(const std::string& prefix, const DNSName& qname, const QType& qtype, const DNSName& auth, LWResult& lwr, const bool sendRDQuery, vector<DNSRecord>& ret, set<DNSName>& nsset, DNSName& newtarget, DNSName& newauth, bool& realreferral, bool& negindic, vState& state, bool needWildcardProof);

Expand Down