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/**
* Copyright (C) 2015 MongoDB Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* 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 GNU Affero General 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.
*/
#include "mongo/platform/basic.h"
#include "mongo/rpc/protocol.h"
#include <algorithm>
#include <iterator>
#include "mongo/base/string_data.h"
#include "mongo/bson/util/bson_extract.h"
#include "mongo/db/jsobj.h"
#include "mongo/db/wire_version.h"
#include "mongo/util/mongoutils/str.h"
namespace mongo {
namespace rpc {
namespace {
/**
* Protocols supported by order of preference.
*/
const Protocol kPreferredProtos[] = {Protocol::kOpMsg, Protocol::kOpCommandV1, Protocol::kOpQuery};
struct ProtocolSetAndName {
StringData name;
ProtocolSet protocols;
};
constexpr ProtocolSetAndName protocolSetNames[] = {
// Most common ones go first.
{"all"_sd, supports::kAll}, // new mongod.
{"opQueryAndOpMsg"_sd, supports::kOpQueryOnly | supports::kOpMsgOnly}, // new mongos.
{"opQueryAndOpCommand"_sd, supports::kOpQueryOnly | supports::kOpCommandOnly}, // old mongod.
{"opQueryOnly"_sd, supports::kOpQueryOnly}, // old mongos or very old client or mongod.
// Then the rest (these should never happen in production).
{"none"_sd, supports::kNone},
{"opCommandOnly"_sd, supports::kOpCommandOnly},
{"opMsgOnly"_sd, supports::kOpMsgOnly},
};
} // namespace
Protocol protocolForMessage(const Message& message) {
switch (message.operation()) {
case mongo::dbMsg:
return Protocol::kOpMsg;
case mongo::dbQuery:
return Protocol::kOpQuery;
case mongo::dbCommand:
return Protocol::kOpCommandV1;
default:
uasserted(ErrorCodes::UnsupportedFormat,
str::stream() << "Received a reply message with unexpected opcode: "
<< message.operation());
}
}
StatusWith<Protocol> negotiate(ProtocolSet fst, ProtocolSet snd) {
using std::begin;
using std::end;
ProtocolSet common = fst & snd;
auto it = std::find_if(begin(kPreferredProtos), end(kPreferredProtos), [common](Protocol p) {
return common & static_cast<ProtocolSet>(p);
});
if (it == end(kPreferredProtos)) {
return Status(ErrorCodes::RPCProtocolNegotiationFailed, "No common protocol found.");
}
return *it;
}
StatusWith<StringData> toString(ProtocolSet protocols) {
for (auto& elem : protocolSetNames) {
if (elem.protocols == protocols)
return elem.name;
}
return Status(ErrorCodes::BadValue,
str::stream() << "ProtocolSet " << protocols
<< " does not match any well-known value.");
}
StatusWith<ProtocolSet> parseProtocolSet(StringData name) {
for (auto& elem : protocolSetNames) {
if (elem.name == name)
return elem.protocols;
}
return Status(ErrorCodes::BadValue,
str::stream() << name << " is not a valid name for a ProtocolSet.");
}
StatusWith<ProtocolSetAndWireVersionInfo> parseProtocolSetFromIsMasterReply(
const BSONObj& isMasterReply) {
long long maxWireVersion;
auto maxWireExtractStatus =
bsonExtractIntegerField(isMasterReply, "maxWireVersion", &maxWireVersion);
long long minWireVersion;
auto minWireExtractStatus =
bsonExtractIntegerField(isMasterReply, "minWireVersion", &minWireVersion);
// MongoDB 2.4 and earlier do not have maxWireVersion/minWireVersion in their 'isMaster' replies
if ((maxWireExtractStatus == minWireExtractStatus) &&
(maxWireExtractStatus == ErrorCodes::NoSuchKey)) {
return {{supports::kOpQueryOnly, {0, 0}}};
} else if (!maxWireExtractStatus.isOK()) {
return maxWireExtractStatus;
} else if (!minWireExtractStatus.isOK()) {
return minWireExtractStatus;
}
bool isMongos = false;
std::string msgField;
auto msgFieldExtractStatus = bsonExtractStringField(isMasterReply, "msg", &msgField);
if (msgFieldExtractStatus == ErrorCodes::NoSuchKey) {
isMongos = false;
} else if (!msgFieldExtractStatus.isOK()) {
return msgFieldExtractStatus;
} else {
isMongos = (msgField == "isdbgrid");
}
if (minWireVersion < 0 || maxWireVersion < 0 ||
minWireVersion >= std::numeric_limits<int>::max() ||
maxWireVersion >= std::numeric_limits<int>::max()) {
return Status(ErrorCodes::IncompatibleServerVersion,
str::stream() << "Server min and max wire version have invalid values ("
<< minWireVersion
<< ","
<< maxWireVersion
<< ")");
}
WireVersionInfo version{static_cast<int>(minWireVersion), static_cast<int>(maxWireVersion)};
auto protos = computeProtocolSet(version);
if (isMongos) {
// Remove support for protocols that mongos doesn't support.
protos &= ~supports::kOpCommandOnly;
}
return {{protos, version}};
}
ProtocolSet computeProtocolSet(const WireVersionInfo version) {
ProtocolSet result = supports::kNone;
if (version.minWireVersion <= version.maxWireVersion) {
if (version.maxWireVersion >= WireVersion::SUPPORTS_OP_MSG) {
result |= supports::kOpMsgOnly;
}
if (version.maxWireVersion >= WireVersion::FIND_COMMAND &&
version.maxWireVersion <= WireVersion::SUPPORTS_OP_MSG) {
// Future versions may remove support for OP_COMMAND.
result |= supports::kOpCommandOnly;
}
if (version.minWireVersion <= WireVersion::RELEASE_2_4_AND_BEFORE) {
result |= supports::kOpQueryOnly;
}
}
return result;
}
Status validateWireVersion(const WireVersionInfo client, const WireVersionInfo server) {
// Since this is defined in the code, it should always hold true since this is the versions that
// mongos/d wants to connect to.
invariant(client.minWireVersion <= client.maxWireVersion);
// Server may return bad data.
if (server.minWireVersion > server.maxWireVersion) {
return Status(ErrorCodes::IncompatibleServerVersion,
str::stream() << "Server min and max wire version are incorrect ("
<< server.minWireVersion
<< ","
<< server.maxWireVersion
<< ")");
}
// Determine if the [min, max] tuples overlap.
// We assert the invariant that min < max above.
if (!(client.minWireVersion <= server.maxWireVersion &&
client.maxWireVersion >= server.minWireVersion)) {
return Status(ErrorCodes::IncompatibleServerVersion,
str::stream() << "Server min and max wire version are incompatible ("
<< server.minWireVersion
<< ","
<< server.maxWireVersion
<< ") with client min wire version ("
<< client.minWireVersion
<< ","
<< client.maxWireVersion
<< ")");
}
return Status::OK();
}
} // namespace rpc
} // namespace mongo
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