include/nbd_proxy.hpp - openbmc/bmcweb - Gitiles

 /*
 // Copyright (c) 2019 Intel Corporation
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //      http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
 */
 #pragma once
 #include <app.hpp>
 #include <boost/asio/buffer.hpp>
 #include <boost/asio/local/stream_protocol.hpp>
 #include <boost/asio/write.hpp>
 #include <boost/beast/core/buffers_to_string.hpp>
 #include <boost/beast/core/multi_buffer.hpp>
 #include <boost/container/flat_map.hpp>
 #include <dbus_utility.hpp>
 #include <privileges.hpp>
 #include <websocket.hpp>

 namespace crow
 {

 namespace nbd_proxy
 {

 using boost::asio::local::stream_protocol;

 static constexpr auto nbdBufferSize = 131088;
 static const char* requiredPrivilegeString = "ConfigureManager";

 struct NbdProxyServer : std::enable_shared_from_this<NbdProxyServer>
 {
     NbdProxyServer(crow::websocket::Connection& connIn,
                    const std::string& socketIdIn,
                    const std::string& endpointIdIn, const std::string& pathIn) :
         socketId(socketIdIn),
         endpointId(endpointIdIn), path(pathIn),
         acceptor(connIn.getIoContext(), stream_protocol::endpoint(socketId)),
         connection(connIn)
     {}

     NbdProxyServer(const NbdProxyServer&) = delete;
     NbdProxyServer(NbdProxyServer&&) = delete;
     NbdProxyServer& operator=(const NbdProxyServer&) = delete;
     NbdProxyServer& operator=(NbdProxyServer&&) = delete;

     ~NbdProxyServer()
     {
         BMCWEB_LOG_DEBUG << "NbdProxyServer destructor";
     }

     std::string getEndpointId() const
     {
         return endpointId;
     }

     void run()
     {
         acceptor.async_accept(
             [this, self(shared_from_this())](boost::system::error_code ec,
                                              stream_protocol::socket socket) {
             if (ec)
             {
                 BMCWEB_LOG_ERROR << "UNIX socket: async_accept error = "
                                  << ec.message();
                 return;
             }
             if (peerSocket)
             {
                 // Something is wrong - socket shouldn't be acquired at this
                 // point
                 BMCWEB_LOG_ERROR
                     << "Failed to open connection - socket already used";
                 return;
             }

             BMCWEB_LOG_DEBUG << "Connection opened";
             peerSocket = std::move(socket);
             doRead();

             // Trigger Write if any data was sent from server
             // Initially this is negotiation chunk
             doWrite();
         });

         auto mountHandler =
             [this, self(shared_from_this())](const boost::system::error_code ec,
                                              const bool) {
             if (ec)
             {
                 BMCWEB_LOG_ERROR << "DBus error: cannot call mount method = "
                                  << ec.message();
                 connection.close("Failed to mount media");
                 return;
             }
         };

         crow::connections::systemBus->async_method_call(
             std::move(mountHandler), "xyz.openbmc_project.VirtualMedia", path,
             "xyz.openbmc_project.VirtualMedia.Proxy", "Mount");
     }

     void send(const std::string_view data)
     {
         boost::asio::buffer_copy(ws2uxBuf.prepare(data.size()),
                                  boost::asio::buffer(data));
         ws2uxBuf.commit(data.size());
         doWrite();
     }

     void close()
     {
         acceptor.close();
         if (peerSocket)
         {
             BMCWEB_LOG_DEBUG << "peerSocket->close()";
             peerSocket->close();
             peerSocket.reset();
             BMCWEB_LOG_DEBUG << "std::remove(" << socketId << ")";
             std::remove(socketId.c_str());
         }
         // The reference to session should exists until unmount is
         // called
         auto unmountHandler = [](const boost::system::error_code ec) {
             if (ec)
             {
                 BMCWEB_LOG_ERROR << "DBus error: " << ec
                                  << ", cannot call unmount method";
                 return;
             }
         };

         crow::connections::systemBus->async_method_call(
             std::move(unmountHandler), "xyz.openbmc_project.VirtualMedia", path,
             "xyz.openbmc_project.VirtualMedia.Proxy", "Unmount");
     }

   private:
     void doRead()
     {
         if (!peerSocket)
         {
             BMCWEB_LOG_DEBUG << "UNIX socket isn't created yet";
             // Skip if UNIX socket is not created yet.
             return;
         }

         // Trigger async read
         peerSocket->async_read_some(
             ux2wsBuf.prepare(nbdBufferSize),
             [this, self(shared_from_this())](boost::system::error_code ec,
                                              std::size_t bytesRead) {
             if (ec)
             {
                 BMCWEB_LOG_ERROR << "UNIX socket: async_read_some error = "
                                  << ec.message();
                 // UNIX socket has been closed by peer, best we can do is to
                 // break all connections
                 close();
                 return;
             }

             // Fetch data from UNIX socket

             ux2wsBuf.commit(bytesRead);

             // Paste it to WebSocket as binary
             connection.sendBinary(
                 boost::beast::buffers_to_string(ux2wsBuf.data()));
             ux2wsBuf.consume(bytesRead);

             // Allow further reads
             doRead();
             });
     }

     void doWrite()
     {
         if (!peerSocket)
         {
             BMCWEB_LOG_DEBUG << "UNIX socket isn't created yet";
             // Skip if UNIX socket is not created yet. Collect data, and wait
             // for nbd-client connection
             return;
         }

         if (uxWriteInProgress)
         {
             BMCWEB_LOG_ERROR << "Write in progress";
             return;
         }

         if (ws2uxBuf.size() == 0)
         {
             BMCWEB_LOG_ERROR << "No data to write to UNIX socket";
             return;
         }

         uxWriteInProgress = true;
         boost::asio::async_write(
             *peerSocket, ws2uxBuf.data(),
             [this, self(shared_from_this())](boost::system::error_code ec,
                                              std::size_t bytesWritten) {
             ws2uxBuf.consume(bytesWritten);
             uxWriteInProgress = false;
             if (ec)
             {
                 BMCWEB_LOG_ERROR << "UNIX: async_write error = "
                                  << ec.message();
                 return;
             }
             // Retrigger doWrite if there is something in buffer
             if (ws2uxBuf.size() > 0)
             {
                 doWrite();
             }
             });
     }

     // Keeps UNIX socket endpoint file path
     const std::string socketId;
     const std::string endpointId;
     const std::string path;

     bool uxWriteInProgress = false;

     // UNIX => WebSocket buffer
     boost::beast::multi_buffer ux2wsBuf;

     // WebSocket <= UNIX buffer
     boost::beast::multi_buffer ws2uxBuf;

     // Default acceptor for UNIX socket
     stream_protocol::acceptor acceptor;

     // The socket used to communicate with the client.
     std::optional<stream_protocol::socket> peerSocket;

     crow::websocket::Connection& connection;
 };

 static boost::container::flat_map<crow::websocket::Connection*,
                                   std::shared_ptr<NbdProxyServer>>
     sessions;

 inline void requestRoutes(App& app)
 {
     BMCWEB_ROUTE(app, "/nbd/<str>")
         .websocket()
         .onopen([](crow::websocket::Connection& conn) {
             BMCWEB_LOG_DEBUG << "nbd-proxy.onopen(" << &conn << ")";

             auto getUserInfoHandler =
                 [&conn](const boost::system::error_code ec,
                         const dbus::utility::DBusPropertiesMap& userInfo) {
             if (ec)
             {
                 BMCWEB_LOG_ERROR << "GetUserInfo failed...";
                 conn.close("Failed to get user information");
                 return;
             }

             const std::string* userRolePtr = nullptr;
             auto userInfoIter = std::find_if(userInfo.begin(), userInfo.end(),
                                              [](const auto& p) {
                 return p.first == "UserPrivilege";
             });
             if (userInfoIter != userInfo.end())
             {
                 userRolePtr = std::get_if<std::string>(&userInfoIter->second);
             }

             std::string userRole{};
             if (userRolePtr != nullptr)
             {
                 userRole = *userRolePtr;
                 BMCWEB_LOG_DEBUG << "userName = " << conn.getUserName()
                                  << " userRole = " << *userRolePtr;
             }

             // Get the user privileges from the role
             ::redfish::Privileges userPrivileges =
                 ::redfish::getUserPrivileges(userRole);

             const ::redfish::Privileges requiredPrivileges{
                 requiredPrivilegeString};

             if (!userPrivileges.isSupersetOf(requiredPrivileges))
             {
                 BMCWEB_LOG_DEBUG << "User " << conn.getUserName()
                                  << " not authorized for nbd connection";
                 conn.close("Unathourized access");
                 return;
             }

             auto openHandler =
                 [&conn](const boost::system::error_code ec,
                         const dbus::utility::ManagedObjectType& objects) {
                 const std::string* socketValue = nullptr;
                 const std::string* endpointValue = nullptr;
                 const std::string* endpointObjectPath = nullptr;

                 if (ec)
                 {
                     BMCWEB_LOG_ERROR << "DBus error: " << ec.message();
                     conn.close("Failed to create mount point");
                     return;
                 }

                 for (const auto& [objectPath, interfaces] : objects)
                 {
                     for (const auto& [interface, properties] : interfaces)
                     {
                         if (interface !=
                             "xyz.openbmc_project.VirtualMedia.MountPoint")
                         {
                             continue;
                         }

                         for (const auto& [name, value] : properties)
                         {
                             if (name == "EndpointId")
                             {
                                 endpointValue =
                                     std::get_if<std::string>(&value);

                                 if (endpointValue == nullptr)
                                 {
                                     BMCWEB_LOG_ERROR
                                         << "EndpointId property value is null";
                                 }
                             }
                             if (name == "Socket")
                             {
                                 socketValue = std::get_if<std::string>(&value);
                                 if (socketValue == nullptr)
                                 {
                                     BMCWEB_LOG_ERROR
                                         << "Socket property value is null";
                                 }
                             }
                         }
                     }

                     if ((endpointValue != nullptr) &&
                         (socketValue != nullptr) &&
                         *endpointValue == conn.req.target())
                     {
                         endpointObjectPath = &objectPath.str;
                         break;
                     }
                 }

                 if (objects.empty() || endpointObjectPath == nullptr)
                 {
                     BMCWEB_LOG_ERROR << "Cannot find requested EndpointId";
                     conn.close("Failed to match EndpointId");
                     return;
                 }

                 for (const auto& session : sessions)
                 {
                     if (session.second->getEndpointId() == conn.req.target())
                     {
                         BMCWEB_LOG_ERROR
                             << "Cannot open new connection - socket is in use";
                         conn.close("Slot is in use");
                         return;
                     }
                 }

                 // If the socket file exists (i.e. after bmcweb crash),
                 // we cannot reuse it.
                 std::remove((*socketValue).c_str());

                 sessions[&conn] = std::make_shared<NbdProxyServer>(
                     conn, *socketValue, *endpointValue, *endpointObjectPath);

                 sessions[&conn]->run();
             };
             crow::connections::systemBus->async_method_call(
                 std::move(openHandler), "xyz.openbmc_project.VirtualMedia",
                 "/xyz/openbmc_project/VirtualMedia",
                 "org.freedesktop.DBus.ObjectManager", "GetManagedObjects");
             };

             crow::connections::systemBus->async_method_call(
                 std::move(getUserInfoHandler),
                 "xyz.openbmc_project.User.Manager", "/xyz/openbmc_project/user",
                 "xyz.openbmc_project.User.Manager", "GetUserInfo",
                 conn.getUserName());
         })
         .onclose(
             [](crow::websocket::Connection& conn, const std::string& reason) {
         BMCWEB_LOG_DEBUG << "nbd-proxy.onclose(reason = '" << reason << "')";
         auto session = sessions.find(&conn);
         if (session == sessions.end())
         {
             BMCWEB_LOG_DEBUG << "No session to close";
             return;
         }
         session->second->close();
         // Remove reference to session in global map
         sessions.erase(session);
         })
         .onmessage([](crow::websocket::Connection& conn,
                       const std::string& data, bool) {
             BMCWEB_LOG_DEBUG << "nbd-proxy.onmessage(len = " << data.length()
                              << ")";
             // Acquire proxy from sessions
             auto session = sessions.find(&conn);
             if (session != sessions.end())
             {
                 if (session->second)
                 {
                     session->second->send(data);
                     return;
                 }
             }
         });
 }
 } // namespace nbd_proxy
 } // namespace crow
	/*
	// Copyright (c) 2019 Intel Corporation
	//
	// Licensed under the Apache License, Version 2.0 (the "License");
	// you may not use this file except in compliance with the License.
	// You may obtain a copy of the License at
	//
	// http://www.apache.org/licenses/LICENSE-2.0
	//
	// Unless required by applicable law or agreed to in writing, software
	// distributed under the License is distributed on an "AS IS" BASIS,
	// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	// See the License for the specific language governing permissions and
	// limitations under the License.
	*/
	#pragma once
	#include <app.hpp>
	#include <boost/asio/buffer.hpp>
	#include <boost/asio/local/stream_protocol.hpp>
	#include <boost/asio/write.hpp>
	#include <boost/beast/core/buffers_to_string.hpp>
	#include <boost/beast/core/multi_buffer.hpp>
	#include <boost/container/flat_map.hpp>
	#include <dbus_utility.hpp>
	#include <privileges.hpp>
	#include <websocket.hpp>

	namespace crow
	{

	namespace nbd_proxy
	{

	using boost::asio::local::stream_protocol;

	static constexpr auto nbdBufferSize = 131088;
	static const char* requiredPrivilegeString = "ConfigureManager";

	struct NbdProxyServer : std::enable_shared_from_this<NbdProxyServer>
	{
	NbdProxyServer(crow::websocket::Connection& connIn,
	const std::string& socketIdIn,
	const std::string& endpointIdIn, const std::string& pathIn) :
	socketId(socketIdIn),
	endpointId(endpointIdIn), path(pathIn),
	acceptor(connIn.getIoContext(), stream_protocol::endpoint(socketId)),
	connection(connIn)
	{}

	NbdProxyServer(const NbdProxyServer&) = delete;
	NbdProxyServer(NbdProxyServer&&) = delete;
	NbdProxyServer& operator=(const NbdProxyServer&) = delete;
	NbdProxyServer& operator=(NbdProxyServer&&) = delete;

	~NbdProxyServer()
	{
	BMCWEB_LOG_DEBUG << "NbdProxyServer destructor";
	}

	std::string getEndpointId() const
	{
	return endpointId;
	}

	void run()
	{
	acceptor.async_accept(
	[this, self(shared_from_this())](boost::system::error_code ec,
	stream_protocol::socket socket) {
	if (ec)
	{
	BMCWEB_LOG_ERROR << "UNIX socket: async_accept error = "
	<< ec.message();
	return;
	}
	if (peerSocket)
	{
	// Something is wrong - socket shouldn't be acquired at this
	// point
	BMCWEB_LOG_ERROR
	<< "Failed to open connection - socket already used";
	return;
	}

	BMCWEB_LOG_DEBUG << "Connection opened";
	peerSocket = std::move(socket);
	doRead();

	// Trigger Write if any data was sent from server
	// Initially this is negotiation chunk
	doWrite();
	});

	auto mountHandler =
	[this, self(shared_from_this())](const boost::system::error_code ec,
	const bool) {
	if (ec)
	{
	BMCWEB_LOG_ERROR << "DBus error: cannot call mount method = "
	<< ec.message();
	connection.close("Failed to mount media");
	return;
	}
	};

	crow::connections::systemBus->async_method_call(
	std::move(mountHandler), "xyz.openbmc_project.VirtualMedia", path,
	"xyz.openbmc_project.VirtualMedia.Proxy", "Mount");
	}

	void send(const std::string_view data)
	{
	boost::asio::buffer_copy(ws2uxBuf.prepare(data.size()),
	boost::asio::buffer(data));
	ws2uxBuf.commit(data.size());
	doWrite();
	}

	void close()
	{
	acceptor.close();
	if (peerSocket)
	{
	BMCWEB_LOG_DEBUG << "peerSocket->close()";
	peerSocket->close();
	peerSocket.reset();
	BMCWEB_LOG_DEBUG << "std::remove(" << socketId << ")";
	std::remove(socketId.c_str());
	}
	// The reference to session should exists until unmount is
	// called
	auto unmountHandler = [](const boost::system::error_code ec) {
	if (ec)
	{
	BMCWEB_LOG_ERROR << "DBus error: " << ec
	<< ", cannot call unmount method";
	return;
	}
	};

	crow::connections::systemBus->async_method_call(
	std::move(unmountHandler), "xyz.openbmc_project.VirtualMedia", path,
	"xyz.openbmc_project.VirtualMedia.Proxy", "Unmount");
	}

	private:
	void doRead()
	{
	if (!peerSocket)
	{
	BMCWEB_LOG_DEBUG << "UNIX socket isn't created yet";
	// Skip if UNIX socket is not created yet.
	return;
	}

	// Trigger async read
	peerSocket->async_read_some(
	ux2wsBuf.prepare(nbdBufferSize),
	[this, self(shared_from_this())](boost::system::error_code ec,
	std::size_t bytesRead) {
	if (ec)
	{
	BMCWEB_LOG_ERROR << "UNIX socket: async_read_some error = "
	<< ec.message();
	// UNIX socket has been closed by peer, best we can do is to
	// break all connections
	close();
	return;
	}

	// Fetch data from UNIX socket

	ux2wsBuf.commit(bytesRead);

	// Paste it to WebSocket as binary
	connection.sendBinary(
	boost::beast::buffers_to_string(ux2wsBuf.data()));
	ux2wsBuf.consume(bytesRead);

	// Allow further reads
	doRead();
	});
	}

	void doWrite()
	{
	if (!peerSocket)
	{
	BMCWEB_LOG_DEBUG << "UNIX socket isn't created yet";
	// Skip if UNIX socket is not created yet. Collect data, and wait
	// for nbd-client connection
	return;
	}

	if (uxWriteInProgress)
	{
	BMCWEB_LOG_ERROR << "Write in progress";
	return;
	}

	if (ws2uxBuf.size() == 0)
	{
	BMCWEB_LOG_ERROR << "No data to write to UNIX socket";
	return;
	}

	uxWriteInProgress = true;
	boost::asio::async_write(
	*peerSocket, ws2uxBuf.data(),
	[this, self(shared_from_this())](boost::system::error_code ec,
	std::size_t bytesWritten) {
	ws2uxBuf.consume(bytesWritten);
	uxWriteInProgress = false;
	if (ec)
	{
	BMCWEB_LOG_ERROR << "UNIX: async_write error = "
	<< ec.message();
	return;
	}
	// Retrigger doWrite if there is something in buffer
	if (ws2uxBuf.size() > 0)
	{
	doWrite();
	}
	});
	}

	// Keeps UNIX socket endpoint file path
	const std::string socketId;
	const std::string endpointId;
	const std::string path;

	bool uxWriteInProgress = false;

	// UNIX => WebSocket buffer
	boost::beast::multi_buffer ux2wsBuf;

	// WebSocket <= UNIX buffer
	boost::beast::multi_buffer ws2uxBuf;

	// Default acceptor for UNIX socket
	stream_protocol::acceptor acceptor;

	// The socket used to communicate with the client.
	std::optional<stream_protocol::socket> peerSocket;

	crow::websocket::Connection& connection;
	};

	static boost::container::flat_map<crow::websocket::Connection*,
	std::shared_ptr<NbdProxyServer>>
	sessions;

	inline void requestRoutes(App& app)
	{
	BMCWEB_ROUTE(app, "/nbd/<str>")
	.websocket()
	.onopen([](crow::websocket::Connection& conn) {
	BMCWEB_LOG_DEBUG << "nbd-proxy.onopen(" << &conn << ")";

	auto getUserInfoHandler =
	[&conn](const boost::system::error_code ec,
	const dbus::utility::DBusPropertiesMap& userInfo) {
	if (ec)
	{
	BMCWEB_LOG_ERROR << "GetUserInfo failed...";
	conn.close("Failed to get user information");
	return;
	}

	const std::string* userRolePtr = nullptr;
	auto userInfoIter = std::find_if(userInfo.begin(), userInfo.end(),
	[](const auto& p) {
	return p.first == "UserPrivilege";
	});
	if (userInfoIter != userInfo.end())
	{
	userRolePtr = std::get_if<std::string>(&userInfoIter->second);
	}

	std::string userRole{};
	if (userRolePtr != nullptr)
	{
	userRole = *userRolePtr;
	BMCWEB_LOG_DEBUG << "userName = " << conn.getUserName()
	<< " userRole = " << *userRolePtr;
	}

	// Get the user privileges from the role
	::redfish::Privileges userPrivileges =
	::redfish::getUserPrivileges(userRole);

	const ::redfish::Privileges requiredPrivileges{
	requiredPrivilegeString};

	if (!userPrivileges.isSupersetOf(requiredPrivileges))
	{
	BMCWEB_LOG_DEBUG << "User " << conn.getUserName()
	<< " not authorized for nbd connection";
	conn.close("Unathourized access");
	return;
	}

	auto openHandler =
	[&conn](const boost::system::error_code ec,
	const dbus::utility::ManagedObjectType& objects) {
	const std::string* socketValue = nullptr;
	const std::string* endpointValue = nullptr;
	const std::string* endpointObjectPath = nullptr;

	if (ec)
	{
	BMCWEB_LOG_ERROR << "DBus error: " << ec.message();
	conn.close("Failed to create mount point");
	return;
	}

	for (const auto& [objectPath, interfaces] : objects)
	{
	for (const auto& [interface, properties] : interfaces)
	{
	if (interface !=
	"xyz.openbmc_project.VirtualMedia.MountPoint")
	{
	continue;
	}

	for (const auto& [name, value] : properties)
	{
	if (name == "EndpointId")
	{
	endpointValue =
	std::get_if<std::string>(&value);

	if (endpointValue == nullptr)
	{
	BMCWEB_LOG_ERROR
	<< "EndpointId property value is null";
	}
	}
	if (name == "Socket")
	{
	socketValue = std::get_if<std::string>(&value);
	if (socketValue == nullptr)
	{
	BMCWEB_LOG_ERROR
	<< "Socket property value is null";
	}
	}
	}
	}

	if ((endpointValue != nullptr) &&
	(socketValue != nullptr) &&
	*endpointValue == conn.req.target())
	{
	endpointObjectPath = &objectPath.str;
	break;
	}
	}

	if (objects.empty() \|\| endpointObjectPath == nullptr)
	{
	BMCWEB_LOG_ERROR << "Cannot find requested EndpointId";
	conn.close("Failed to match EndpointId");
	return;
	}

	for (const auto& session : sessions)
	{
	if (session.second->getEndpointId() == conn.req.target())
	{
	BMCWEB_LOG_ERROR
	<< "Cannot open new connection - socket is in use";
	conn.close("Slot is in use");
	return;
	}
	}

	// If the socket file exists (i.e. after bmcweb crash),
	// we cannot reuse it.
	std::remove((*socketValue).c_str());

	sessions[&conn] = std::make_shared<NbdProxyServer>(
	conn, socketValue, endpointValue, *endpointObjectPath);

	sessions[&conn]->run();
	};
	crow::connections::systemBus->async_method_call(
	std::move(openHandler), "xyz.openbmc_project.VirtualMedia",
	"/xyz/openbmc_project/VirtualMedia",
	"org.freedesktop.DBus.ObjectManager", "GetManagedObjects");
	};

	crow::connections::systemBus->async_method_call(
	std::move(getUserInfoHandler),
	"xyz.openbmc_project.User.Manager", "/xyz/openbmc_project/user",
	"xyz.openbmc_project.User.Manager", "GetUserInfo",
	conn.getUserName());
	})
	.onclose(
	[](crow::websocket::Connection& conn, const std::string& reason) {
	BMCWEB_LOG_DEBUG << "nbd-proxy.onclose(reason = '" << reason << "')";
	auto session = sessions.find(&conn);
	if (session == sessions.end())
	{
	BMCWEB_LOG_DEBUG << "No session to close";
	return;
	}
	session->second->close();
	// Remove reference to session in global map
	sessions.erase(session);
	})
	.onmessage([](crow::websocket::Connection& conn,
	const std::string& data, bool) {
	BMCWEB_LOG_DEBUG << "nbd-proxy.onmessage(len = " << data.length()
	<< ")";
	// Acquire proxy from sessions
	auto session = sessions.find(&conn);
	if (session != sessions.end())
	{
	if (session->second)
	{
	session->second->send(data);
	return;
	}
	}
	});
	}
	} // namespace nbd_proxy
	} // namespace crow