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/**
* Copyright (C) 2018-present MongoDB, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Server Side Public License, version 1,
* as published by MongoDB, Inc.
*
* 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
* Server Side Public License for more details.
*
* You should have received a copy of the Server Side Public License
* along with this program. If not, see
* <http://www.mongodb.com/licensing/server-side-public-license>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the Server Side Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#define MONGO_LOGV2_DEFAULT_COMPONENT ::mongo::logv2::LogComponent::kCommand
#include "mongo/platform/basic.h"
#include "mongo/base/string_data.h"
#include "mongo/bson/util/bson_extract.h"
#include "mongo/db/auth/sasl_mechanism_registry.h"
#include "mongo/db/client.h"
#include "mongo/db/commands.h"
#include "mongo/db/logical_session_id.h"
#include "mongo/db/operation_context.h"
#include "mongo/db/ops/write_ops.h"
#include "mongo/db/repl/speculative_auth.h"
#include "mongo/db/wire_version.h"
#include "mongo/logv2/log.h"
#include "mongo/rpc/metadata/client_metadata.h"
#include "mongo/rpc/metadata/client_metadata_ismaster.h"
#include "mongo/rpc/topology_version_gen.h"
#include "mongo/transport/ismaster_metrics.h"
#include "mongo/transport/message_compressor_manager.h"
#include "mongo/util/map_util.h"
#include "mongo/util/net/socket_utils.h"
#include "mongo/util/version.h"
namespace mongo {
// Hangs in the beginning of each isMaster command when set.
MONGO_FAIL_POINT_DEFINE(waitInIsMaster);
// Awaitable isMaster requests with the proper topologyVersions are expected to sleep for
// maxAwaitTimeMS on mongos. This failpoint will hang right before doing this sleep when set.
MONGO_FAIL_POINT_DEFINE(hangWhileWaitingForIsMasterResponse);
TopologyVersion mongosTopologyVersion;
MONGO_INITIALIZER(GenerateMongosTopologyVersion)(InitializerContext*) {
mongosTopologyVersion = TopologyVersion(OID::gen(), 0);
return Status::OK();
}
namespace {
constexpr auto kHelloString = "hello"_sd;
// Aliases for the hello command in order to provide backwards compatibility.
constexpr auto kCamelCaseIsMasterString = "isMaster"_sd;
constexpr auto kLowerCaseIsMasterString = "ismaster"_sd;
class CmdHello : public BasicCommandWithReplyBuilderInterface {
public:
CmdHello()
: BasicCommandWithReplyBuilderInterface(
kHelloString, {kCamelCaseIsMasterString, kLowerCaseIsMasterString}) {}
bool supportsWriteConcern(const BSONObj& cmd) const override {
return false;
}
AllowedOnSecondary secondaryAllowed(ServiceContext*) const override {
return AllowedOnSecondary::kAlways;
}
std::string help() const override {
return "Status information for clients negotiating a connection with this server";
}
void addRequiredPrivileges(const std::string& dbname,
const BSONObj& cmdObj,
std::vector<Privilege>* out) const override {
// No auth required
}
bool requiresAuth() const override {
return false;
}
bool runWithReplyBuilder(OperationContext* opCtx,
const std::string& dbname,
const BSONObj& cmdObj,
rpc::ReplyBuilderInterface* replyBuilder) final {
CommandHelpers::handleMarkKillOnClientDisconnect(opCtx);
waitInIsMaster.pauseWhileSet(opCtx);
auto& clientMetadataIsMasterState = ClientMetadataIsMasterState::get(opCtx->getClient());
bool seenIsMaster = clientMetadataIsMasterState.hasSeenIsMaster();
if (!seenIsMaster) {
clientMetadataIsMasterState.setSeenIsMaster();
}
BSONElement element = cmdObj[kMetadataDocumentName];
if (!element.eoo()) {
if (seenIsMaster) {
uasserted(ErrorCodes::ClientMetadataCannotBeMutated,
"The client metadata document may only be sent in the first isMaster");
}
auto swParseClientMetadata = ClientMetadata::parse(element);
uassertStatusOK(swParseClientMetadata.getStatus());
invariant(swParseClientMetadata.getValue());
swParseClientMetadata.getValue().get().logClientMetadata(opCtx->getClient());
swParseClientMetadata.getValue().get().setMongoSMetadata(
getHostNameCachedAndPort(),
opCtx->getClient()->clientAddress(true),
VersionInfoInterface::instance().version());
clientMetadataIsMasterState.setClientMetadata(
opCtx->getClient(), std::move(swParseClientMetadata.getValue()));
}
// If a client is following the awaitable isMaster protocol, maxAwaitTimeMS should be
// present if and only if topologyVersion is present in the request.
auto topologyVersionElement = cmdObj["topologyVersion"];
auto maxAwaitTimeMSField = cmdObj["maxAwaitTimeMS"];
boost::optional<TopologyVersion> clientTopologyVersion;
if (topologyVersionElement && maxAwaitTimeMSField) {
clientTopologyVersion = TopologyVersion::parse(IDLParserErrorContext("TopologyVersion"),
topologyVersionElement.Obj());
uassert(51758,
"topologyVersion must have a non-negative counter",
clientTopologyVersion->getCounter() >= 0);
long long maxAwaitTimeMS;
uassertStatusOK(bsonExtractIntegerField(cmdObj, "maxAwaitTimeMS", &maxAwaitTimeMS));
uassert(51759, "maxAwaitTimeMS must be a non-negative integer", maxAwaitTimeMS >= 0);
LOGV2_DEBUG(23871, 3, "Using maxAwaitTimeMS for awaitable isMaster protocol.");
// Awaitable isMaster commands have high latency by design. Ignore them.
opCtx->setShouldIncrementLatencyStats(false);
if (clientTopologyVersion->getProcessId() == mongosTopologyVersion.getProcessId()) {
uassert(51761,
str::stream()
<< "Received a topology version with counter: "
<< clientTopologyVersion->getCounter()
<< " which is greater than the mongos topology version counter: "
<< mongosTopologyVersion.getCounter(),
clientTopologyVersion->getCounter() == mongosTopologyVersion.getCounter());
// The topologyVersion never changes on a running mongos process, so just sleep for
// maxAwaitTimeMS.
IsMasterMetrics::get(opCtx)->incrementNumAwaitingTopologyChanges();
ON_BLOCK_EXIT(
[&] { IsMasterMetrics::get(opCtx)->decrementNumAwaitingTopologyChanges(); });
if (MONGO_unlikely(hangWhileWaitingForIsMasterResponse.shouldFail())) {
LOGV2(31463, "hangWhileWaitingForIsMasterResponse failpoint enabled.");
hangWhileWaitingForIsMasterResponse.pauseWhileSet(opCtx);
}
opCtx->sleepFor(Milliseconds(maxAwaitTimeMS));
}
} else {
uassert(51760,
(topologyVersionElement
? "A request with a 'topologyVersion' must include 'maxAwaitTimeMS'"
: "A request with 'maxAwaitTimeMS' must include a 'topologyVersion'"),
!topologyVersionElement && !maxAwaitTimeMSField);
}
auto result = replyBuilder->getBodyBuilder();
result.appendBool("ismaster", true);
result.append("msg", "isdbgrid");
result.appendNumber("maxBsonObjectSize", BSONObjMaxUserSize);
result.appendNumber("maxMessageSizeBytes", MaxMessageSizeBytes);
result.appendNumber("maxWriteBatchSize", write_ops::kMaxWriteBatchSize);
result.appendDate("localTime", jsTime());
result.append("logicalSessionTimeoutMinutes", localLogicalSessionTimeoutMinutes);
result.appendNumber("connectionId", opCtx->getClient()->getConnectionId());
// Mongos tries to keep exactly the same version range of the server for which
// it is compiled.
result.append("maxWireVersion", WireSpec::instance().incomingExternalClient.maxWireVersion);
result.append("minWireVersion", WireSpec::instance().incomingExternalClient.minWireVersion);
const auto parameter = mapFindWithDefault(ServerParameterSet::getGlobal()->getMap(),
"automationServiceDescriptor",
static_cast<ServerParameter*>(nullptr));
if (parameter)
parameter->append(opCtx, result, "automationServiceDescriptor");
MessageCompressorManager::forSession(opCtx->getClient()->session())
.serverNegotiate(cmdObj, &result);
auto& saslMechanismRegistry = SASLServerMechanismRegistry::get(opCtx->getServiceContext());
saslMechanismRegistry.advertiseMechanismNamesForUser(opCtx, cmdObj, &result);
BSONObjBuilder topologyVersionBuilder(result.subobjStart("topologyVersion"));
mongosTopologyVersion.serialize(&topologyVersionBuilder);
topologyVersionBuilder.done();
if (opCtx->isExhaust()) {
LOGV2_DEBUG(23872, 3, "Using exhaust for isMaster protocol");
uassert(51763,
"An isMaster request with exhaust must specify 'maxAwaitTimeMS'",
maxAwaitTimeMSField);
invariant(clientTopologyVersion);
InExhaustIsMaster::get(opCtx->getClient()->session().get())
->setInExhaustIsMaster(true /* inExhaustIsMaster */);
if (clientTopologyVersion->getProcessId() == mongosTopologyVersion.getProcessId() &&
clientTopologyVersion->getCounter() == mongosTopologyVersion.getCounter()) {
// Indicate that an exhaust message should be generated and the previous BSONObj
// command parameters should be reused as the next BSONObj command parameters.
replyBuilder->setNextInvocation(boost::none);
} else {
BSONObjBuilder nextInvocationBuilder;
for (auto&& elt : cmdObj) {
if (elt.fieldNameStringData() == "topologyVersion"_sd) {
BSONObjBuilder topologyVersionBuilder(
nextInvocationBuilder.subobjStart("topologyVersion"));
mongosTopologyVersion.serialize(&topologyVersionBuilder);
} else {
nextInvocationBuilder.append(elt);
}
}
replyBuilder->setNextInvocation(nextInvocationBuilder.obj());
}
}
handleIsMasterSpeculativeAuth(opCtx, cmdObj, &result);
return true;
}
} hello;
} // namespace
} // namespace mongo
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