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[dns-client] track limited query (one question) servers (#10403)

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This commit updates `Dns::Client` to remember servers/resolvers that
are known to have trouble with multiple-question queries. This
information is learned from earlier interactions with the server.

When `ResolveService()` is requested, if the user explicitly
requests "optimize" service mode, the request is honored. Otherwise,
if "optimize" service mode is chosen from the default configuration
and the DNS server is known to have trouble with multiple-question
queries, "separate" service mode is used instead.

This commit also updates the `test_dns_client.cpp` unit test to
validate the newly added behavior.
This commit is contained in:
Abtin Keshavarzian
2024-08-14 12:41:18 -07:00
committed by GitHub
parent 1645880b8e
commit 9fd6596e7b
4 changed files with 154 additions and 10 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/core/net/dns_client.cpp
+65
View File
@@ -791,6 +791,8 @@ void Client::Stop(void)
IgnoreError(mEndpoint.Deinitialize());
}
#endif
mLimitedQueryServers.Clear();
}
#if OPENTHREAD_CONFIG_DNS_CLIENT_OVER_TCP_ENABLE
@@ -938,6 +940,8 @@ Error Client::Resolve(const char *aInstanceLabel,
info.mConfig.SetFrom(aConfig, mDefaultConfig);
info.mShouldResolveHostAddr = aShouldResolveHostAddr;
CheckAndUpdateServiceMode(info.mConfig, aConfig);
switch (info.mConfig.GetServiceMode())
{
case QueryConfig::kServiceModeSrvTxtSeparate:
@@ -1402,6 +1406,11 @@ Error Client::ParseResponse(const Message &aResponseMessage, Query *&aQuery, Err
aResponseError = Header::ResponseCodeToError(header.GetResponseCode());
if ((aResponseError == kErrorNone) && (info.mQueryType == kServiceQuerySrvTxt))
{
RecordServerAsCapableOfMultiQuestions(info.mConfig.GetServerSockAddr().GetAddress());
}
exit:
return error;
}
@@ -1591,6 +1600,60 @@ exit:
#if OPENTHREAD_CONFIG_DNS_CLIENT_SERVICE_DISCOVERY_ENABLE
void Client::CheckAndUpdateServiceMode(QueryConfig &aConfig, const QueryConfig *aRequestConfig) const
{
// If the user explicitly requested "optimize" mode, we honor that
// request. Otherwise, if "optimize" is chosen from the default
// config, we check if the DNS server is known to have trouble
// with multiple-question queries. If so, we switch to "separate"
// mode.
if ((aRequestConfig != nullptr) && (aRequestConfig->GetServiceMode() == QueryConfig::kServiceModeSrvTxtOptimize))
{
ExitNow();
}
VerifyOrExit(aConfig.GetServiceMode() == QueryConfig::kServiceModeSrvTxtOptimize);
if (mLimitedQueryServers.Contains(aConfig.GetServerSockAddr().GetAddress()))
{
aConfig.SetServiceMode(QueryConfig::kServiceModeSrvTxtSeparate);
}
exit:
return;
}
void Client::RecordServerAsLimitedToSingleQuestion(const Ip6::Address &aServerAddress)
{
VerifyOrExit(!aServerAddress.IsUnspecified());
VerifyOrExit(!mLimitedQueryServers.Contains(aServerAddress));
if (mLimitedQueryServers.IsFull())
{
uint8_t randomIndex = Random::NonCrypto::GetUint8InRange(0, mLimitedQueryServers.GetMaxSize());
mLimitedQueryServers.Remove(mLimitedQueryServers[randomIndex]);
}
IgnoreError(mLimitedQueryServers.PushBack(aServerAddress));
exit:
return;
}
void Client::RecordServerAsCapableOfMultiQuestions(const Ip6::Address &aServerAddress)
{
Ip6::Address *entry = mLimitedQueryServers.Find(aServerAddress);
VerifyOrExit(entry != nullptr);
mLimitedQueryServers.Remove(*entry);
exit:
return;
}
Error Client::ReplaceWithSeparateSrvTxtQueries(Query &aQuery)
{
Error error = kErrorFailed;
@@ -1602,6 +1665,8 @@ Error Client::ReplaceWithSeparateSrvTxtQueries(Query &aQuery)
VerifyOrExit(info.mQueryType == kServiceQuerySrvTxt);
VerifyOrExit(info.mConfig.GetServiceMode() == QueryConfig::kServiceModeSrvTxtOptimize);
RecordServerAsLimitedToSingleQuestion(info.mConfig.GetServerSockAddr().GetAddress());
secondQuery = aQuery.Clone();
VerifyOrExit(secondQuery != nullptr);
src/core/net/dns_client.hpp
+6 -1
View File
@@ -770,7 +770,8 @@ public:
#endif // OPENTHREAD_CONFIG_DNS_CLIENT_SERVICE_DISCOVERY_ENABLE
private:
static constexpr uint16_t kMaxCnameAliasNameChanges = 40;
static constexpr uint16_t kMaxCnameAliasNameChanges = 40;
static constexpr uint8_t kLimitedQueryServersArraySize = 3;
enum QueryType : uint8_t
{
@@ -858,6 +859,9 @@ private:
void *aContext,
const QueryConfig *aConfig,
bool aShouldResolveHostAddr);
void CheckAndUpdateServiceMode(QueryConfig &aConfig, const QueryConfig *aRequestConfig) const;
void RecordServerAsLimitedToSingleQuestion(const Ip6::Address &aServerAddress);
void RecordServerAsCapableOfMultiQuestions(const Ip6::Address &aServerAddress);
Error ReplaceWithSeparateSrvTxtQueries(Query &aQuery);
void ResolveHostAddressIfNeeded(Query &aQuery, const Message &aResponseMessage);
#endif
@@ -925,6 +929,7 @@ private:
#if OPENTHREAD_CONFIG_DNS_CLIENT_DEFAULT_SERVER_ADDRESS_AUTO_SET_ENABLE
bool mUserDidSetDefaultAddress;
#endif
Array<Ip6::Address, kLimitedQueryServersArraySize> mLimitedQueryServers;
};
} // namespace Dns
src/core/net/dnssd_server.hpp
+21
View File
@@ -49,6 +49,7 @@
#include "border_router/infra_if.hpp"
#include "common/as_core_type.hpp"
#include "common/callback.hpp"
#include "common/equatable.hpp"
#include "common/message.hpp"
#include "common/non_copyable.hpp"
#include "common/owned_ptr.hpp"
@@ -96,6 +97,26 @@ public:
*/
class Counters : public otDnssdCounters, public Clearable<Counters>
{
public:
/**
* Returns the total number of processed queries (successful or failed responses).
*
* @return The total number of queries.
*
*/
uint32_t GetTotalQueries(void) const { return mSuccessResponse + GetTotalFailedQueries(); }
/**
* Returns the total number of failed queries (any error response code).
*
* @return The total number of failed queries.
*
*/
uint32_t GetTotalFailedQueries(void) const
{
return mServerFailureResponse + mFormatErrorResponse + mNameErrorResponse + mNotImplementedResponse +
mOtherResponse;
}
};
#if OPENTHREAD_CONFIG_DNS_UPSTREAM_QUERY_ENABLE
tests/unit/test_dns_client.cpp
+62 -9
View File
@@ -497,15 +497,17 @@ void TestDnsClient(void)
Dns::Client::QueryConfig::kServiceModeSrvTxtOptimize,
};
Array<Ip6::Address, kNumAddresses> addresses;
Srp::Server *srpServer;
Srp::Client *srpClient;
Srp::Client::Service service1;
Srp::Client::Service service2;
Dns::Client *dnsClient;
Dns::Client::QueryConfig queryConfig;
Dns::ServiceDiscovery::Server *dnsServer;
uint16_t heapAllocations;
Array<Ip6::Address, kNumAddresses> addresses;
Srp::Server *srpServer;
Srp::Client *srpClient;
Srp::Client::Service service1;
Srp::Client::Service service2;
Dns::Client *dnsClient;
Dns::Client::QueryConfig queryConfig;
Dns::ServiceDiscovery::Server *dnsServer;
Dns::ServiceDiscovery::Server::Counters oldServerCounters;
Dns::ServiceDiscovery::Server::Counters newServerCounters;
uint16_t heapAllocations;
Log("--------------------------------------------------------------------------------------------");
Log("TestDnsClient");
@@ -882,6 +884,8 @@ void TestDnsClient(void)
queryConfig.Clear();
queryConfig.mServiceMode = static_cast<otDnsServiceMode>(Dns::Client::QueryConfig::kServiceModeSrvTxtOptimize);
oldServerCounters = dnsServer->GetCounters();
sResolveServiceInfo.Reset();
SuccessOrQuit(dnsClient->ResolveServiceAndHostAddress(kInstance1Label, kService1FullName, ServiceCallback,
sInstance, &queryConfig));
@@ -907,6 +911,55 @@ void TestDnsClient(void)
VerifyOrQuit(addresses.Contains(sResolveServiceInfo.mHostAddresses[index]));
}
newServerCounters = dnsServer->GetCounters();
Log("Validate (using server counter) that client first tried to query SRV/TXT together and failed");
Log("and then send separate queries (for SRV, TXT and AAAA)");
Log(" Total : %2u -> %2u", oldServerCounters.GetTotalQueries(), newServerCounters.GetTotalQueries());
Log(" Failed: %2u -> %2u", oldServerCounters.GetTotalFailedQueries(), newServerCounters.GetTotalFailedQueries());
VerifyOrQuit(newServerCounters.GetTotalFailedQueries() == 1 + oldServerCounters.GetTotalFailedQueries());
VerifyOrQuit(newServerCounters.GetTotalQueries() == 4 + oldServerCounters.GetTotalQueries());
Log("- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ");
Log("Resolve service again now using `kServiceModeSrvTxtOptimize` as default config");
Log("Client should already know that server is not capable of handling multi-question query");
queryConfig.Clear();
queryConfig.mServiceMode = static_cast<otDnsServiceMode>(Dns::Client::QueryConfig::kServiceModeSrvTxtOptimize);
dnsClient->SetDefaultConfig(queryConfig);
Log("ResolveService(%s,%s)", kInstance1Label, kService1FullName);
oldServerCounters = dnsServer->GetCounters();
sResolveServiceInfo.Reset();
SuccessOrQuit(dnsClient->ResolveService(kInstance1Label, kService1FullName, ServiceCallback, sInstance, nullptr));
AdvanceTime(100);
VerifyOrQuit(sResolveServiceInfo.mCallbackCount == 1);
SuccessOrQuit(sResolveServiceInfo.mError);
VerifyOrQuit(sResolveServiceInfo.mInfo.mTtl != 0);
VerifyOrQuit(sResolveServiceInfo.mInfo.mPort == service1.mPort);
VerifyOrQuit(sResolveServiceInfo.mInfo.mWeight == service1.mWeight);
VerifyOrQuit(strcmp(sResolveServiceInfo.mInfo.mHostNameBuffer, kHostFullName) == 0);
VerifyOrQuit(sResolveServiceInfo.mInfo.mTxtDataTtl != 0);
VerifyOrQuit(sResolveServiceInfo.mInfo.mTxtDataSize != 0);
newServerCounters = dnsServer->GetCounters();
Log("Client should already know that server is not capable of handling multi-question query");
Log("Check server counters to validate that client did send separate queries for TXT and SRV");
Log(" Total : %2u -> %2u", oldServerCounters.GetTotalQueries(), newServerCounters.GetTotalQueries());
Log(" Failed: %2u -> %2u", oldServerCounters.GetTotalFailedQueries(), newServerCounters.GetTotalFailedQueries());
VerifyOrQuit(newServerCounters.GetTotalFailedQueries() == oldServerCounters.GetTotalFailedQueries());
VerifyOrQuit(newServerCounters.GetTotalQueries() == 2 + oldServerCounters.GetTotalQueries());
dnsServer->SetTestMode(Dns::ServiceDiscovery::Server::kTestModeDisabled);
Log("- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ");