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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.
*/
#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::kOpQuery};
struct ProtocolSetAndName {
StringData name;
ProtocolSet protocols;
};
constexpr ProtocolSetAndName protocolSetNames[] = {
// Most common ones go first.
{"all"_sd, supports::kAll}, // new mongod and mongos or very new client.
{"opQueryOnly"_sd, supports::kOpQueryOnly}, // old mongos or mongod or moderately old client.
// Then the rest (these should never happen in production).
{"none"_sd, supports::kNone},
{"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;
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;
}
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);
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.minWireVersion <= WireVersion::RELEASE_2_4_AND_BEFORE) {
result |= supports::kOpQueryOnly;
}
// Note: this means anything using the internal handshake cannot talk to servers between 2.6
// and 3.6, since the servers will reply with higher minWireVersions. The shell should still
// be able to connect to those versions but will just use OP_QUERY to run commands.
}
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)) {
std::string errmsg = str::stream()
<< "Server min and max wire version (" << server.minWireVersion << ","
<< server.maxWireVersion << ") is incompatible with client min wire version ("
<< client.minWireVersion << "," << client.maxWireVersion << ").";
if (client.maxWireVersion < server.minWireVersion) {
return Status(ErrorCodes::IncompatibleWithUpgradedServer,
str::stream()
<< errmsg
<< "You (client) are attempting to connect to a node (server) that "
"no longer accepts connections with your (client’s) binary "
"version. Please upgrade the client’s binary version.");
}
return Status(ErrorCodes::IncompatibleServerVersion,
str::stream() << errmsg
<< "You (client) are attempting to connect to a node "
"(server) with a binary version with which "
"you (client) no longer accept connections. Please "
"upgrade the server’s binary version.");
}
return Status::OK();
}
} // namespace rpc
} // namespace mongo
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