X-Git-Url: https://git.r.bdr.sh/rbdr/mobius/blobdiff_plain/df1ade5433b027f9cb905e584921692313e647f5..70c2c1100ac57b9444e71fd76b5c5f3205c71024:/hotline/server.go diff --git a/hotline/server.go b/hotline/server.go index e685afd..e4232b6 100644 --- a/hotline/server.go +++ b/hotline/server.go @@ -2,7 +2,6 @@ package hotline import ( "bufio" - "bytes" "context" "encoding/binary" "errors" @@ -12,13 +11,11 @@ import ( "gopkg.in/yaml.v3" "io" "io/fs" - "io/ioutil" "math/big" "math/rand" "net" "os" "path/filepath" - "runtime/debug" "strings" "sync" "time" @@ -30,42 +27,52 @@ var contextKeyReq = contextKey("req") type requestCtx struct { remoteAddr string - login string - name string } -const ( - userIdleSeconds = 300 // time in seconds before an inactive user is marked idle - idleCheckInterval = 10 // time in seconds to check for idle users - trackerUpdateFrequency = 300 // time in seconds between tracker re-registration -) - -var nostalgiaVersion = []byte{0, 0, 2, 0x2c} // version ID used by the Nostalgia client - type Server struct { - Port int - Accounts map[string]*Account - Agreement []byte - Clients map[uint16]*ClientConn - ThreadedNews *ThreadedNews - + NetInterface string + Port int + Accounts map[string]*Account + Agreement []byte + Clients map[uint16]*ClientConn fileTransfers map[[4]byte]*FileTransfer - Config *Config - ConfigDir string - Logger *zap.SugaredLogger - PrivateChats map[uint32]*PrivateChat + Config *Config + ConfigDir string + Logger *zap.SugaredLogger + + PrivateChatsMu sync.Mutex + PrivateChats map[uint32]*PrivateChat + NextGuestID *uint16 TrackerPassID [4]byte - Stats *Stats + + StatsMu sync.Mutex + Stats *Stats FS FileStore // Storage backend to use for File storage outbox chan Transaction mux sync.Mutex + threadedNewsMux sync.Mutex + ThreadedNews *ThreadedNews + flatNewsMux sync.Mutex FlatNews []byte + + banListMU sync.Mutex + banList map[string]*time.Time +} + +func (s *Server) CurrentStats() Stats { + s.StatsMu.Lock() + defer s.StatsMu.Unlock() + + stats := s.Stats + stats.CurrentlyConnected = len(s.Clients) + + return *stats } type PrivateChat struct { @@ -76,15 +83,15 @@ type PrivateChat struct { func (s *Server) ListenAndServe(ctx context.Context, cancelRoot context.CancelFunc) error { s.Logger.Infow("Hotline server started", "version", VERSION, - "API port", fmt.Sprintf(":%v", s.Port), - "Transfer port", fmt.Sprintf(":%v", s.Port+1), + "API port", fmt.Sprintf("%s:%v", s.NetInterface, s.Port), + "Transfer port", fmt.Sprintf("%s:%v", s.NetInterface, s.Port+1), ) var wg sync.WaitGroup wg.Add(1) go func() { - ln, err := net.Listen("tcp", fmt.Sprintf("%s:%v", "", s.Port)) + ln, err := net.Listen("tcp", fmt.Sprintf("%s:%v", s.NetInterface, s.Port)) if err != nil { s.Logger.Fatal(err) } @@ -94,10 +101,9 @@ func (s *Server) ListenAndServe(ctx context.Context, cancelRoot context.CancelFu wg.Add(1) go func() { - ln, err := net.Listen("tcp", fmt.Sprintf("%s:%v", "", s.Port+1)) + ln, err := net.Listen("tcp", fmt.Sprintf("%s:%v", s.NetInterface, s.Port+1)) if err != nil { s.Logger.Fatal(err) - } s.Logger.Fatal(s.ServeFileTransfers(ctx, ln)) @@ -133,7 +139,6 @@ func (s *Server) ServeFileTransfers(ctx context.Context, ln net.Listener) error } func (s *Server) sendTransaction(t Transaction) error { - requestNum := binary.BigEndian.Uint16(t.Type) clientID, err := byteToInt(*t.clientID) if err != nil { return err @@ -145,27 +150,17 @@ func (s *Server) sendTransaction(t Transaction) error { if client == nil { return fmt.Errorf("invalid client id %v", *t.clientID) } - userName := string(client.UserName) - login := client.Account.Login - - handler := TransactionHandlers[requestNum] b, err := t.MarshalBinary() if err != nil { return err } - var n int - if n, err = client.Connection.Write(b); err != nil { + + _, err = client.Connection.Write(b) + if err != nil { return err } - s.Logger.Debugw("Sent Transaction", - "name", userName, - "login", login, - "IsReply", t.IsReply, - "type", handler.Name, - "sentBytes", n, - "remoteAddr", client.RemoteAddr, - ) + return nil } @@ -193,8 +188,10 @@ func (s *Server) Serve(ctx context.Context, ln net.Listener) error { }) go func() { + s.Logger.Infow("Connection established", "RemoteAddr", conn.RemoteAddr()) + + defer conn.Close() if err := s.handleNewConnection(connCtx, conn, conn.RemoteAddr().String()); err != nil { - s.Logger.Infow("New client connection established", "RemoteAddr", conn.RemoteAddr()) if err == io.EOF { s.Logger.Infow("Client disconnected", "RemoteAddr", conn.RemoteAddr()) } else { @@ -210,8 +207,9 @@ const ( ) // NewServer constructs a new Server from a config dir -func NewServer(configDir string, netPort int, logger *zap.SugaredLogger, FS FileStore) (*Server, error) { +func NewServer(configDir, netInterface string, netPort int, logger *zap.SugaredLogger, fs FileStore) (*Server, error) { server := Server{ + NetInterface: netInterface, Port: netPort, Accounts: make(map[string]*Account), Config: new(Config), @@ -222,9 +220,10 @@ func NewServer(configDir string, netPort int, logger *zap.SugaredLogger, FS File Logger: logger, NextGuestID: new(uint16), outbox: make(chan Transaction), - Stats: &Stats{StartTime: time.Now()}, + Stats: &Stats{Since: time.Now()}, ThreadedNews: &ThreadedNews{}, - FS: FS, + FS: fs, + banList: make(map[string]*time.Time), } var err error @@ -243,6 +242,9 @@ func NewServer(configDir string, netPort int, logger *zap.SugaredLogger, FS File return nil, err } + // try to load the ban list, but ignore errors as this file may not be present or may be empty + _ = server.loadBanList(filepath.Join(configDir, "Banlist.yaml")) + if err := server.loadThreadedNews(filepath.Join(configDir, "ThreadedNews.yaml")); err != nil { return nil, err } @@ -255,7 +257,10 @@ func NewServer(configDir string, netPort int, logger *zap.SugaredLogger, FS File return nil, err } - server.Config.FileRoot = filepath.Join(configDir, "Files") + // If the FileRoot is an absolute path, use it, otherwise treat as a relative path to the config dir. + if !filepath.IsAbs(server.Config.FileRoot) { + server.Config.FileRoot = filepath.Join(configDir, server.Config.FileRoot) + } *server.NextGuestID = 1 @@ -279,7 +284,7 @@ func NewServer(configDir string, netPort int, logger *zap.SugaredLogger, FS File if err := register(t, tr); err != nil { server.Logger.Errorw("unable to register with tracker %v", "error", err) } - server.Logger.Infow("Sent Tracker registration", "data", tr) + server.Logger.Debugw("Sent Tracker registration", "addr", t) } time.Sleep(trackerUpdateFrequency * time.Second) @@ -310,16 +315,16 @@ func (s *Server) keepaliveHandler() { if c.IdleTime > userIdleSeconds && !c.Idle { c.Idle = true - flagBitmap := big.NewInt(int64(binary.BigEndian.Uint16(*c.Flags))) - flagBitmap.SetBit(flagBitmap, userFlagAway, 1) - binary.BigEndian.PutUint16(*c.Flags, uint16(flagBitmap.Int64())) + flagBitmap := big.NewInt(int64(binary.BigEndian.Uint16(c.Flags))) + flagBitmap.SetBit(flagBitmap, UserFlagAway, 1) + binary.BigEndian.PutUint16(c.Flags, uint16(flagBitmap.Int64())) c.sendAll( - tranNotifyChangeUser, - NewField(fieldUserID, *c.ID), - NewField(fieldUserFlags, *c.Flags), - NewField(fieldUserName, c.UserName), - NewField(fieldUserIconID, *c.Icon), + TranNotifyChangeUser, + NewField(FieldUserID, *c.ID), + NewField(FieldUserFlags, c.Flags), + NewField(FieldUserName, c.UserName), + NewField(FieldUserIconID, c.Icon), ) } } @@ -327,15 +332,31 @@ func (s *Server) keepaliveHandler() { } } +func (s *Server) writeBanList() error { + s.banListMU.Lock() + defer s.banListMU.Unlock() + + out, err := yaml.Marshal(s.banList) + if err != nil { + return err + } + err = os.WriteFile( + filepath.Join(s.ConfigDir, "Banlist.yaml"), + out, + 0666, + ) + return err +} + func (s *Server) writeThreadedNews() error { - s.mux.Lock() - defer s.mux.Unlock() + s.threadedNewsMux.Lock() + defer s.threadedNewsMux.Unlock() out, err := yaml.Marshal(s.ThreadedNews) if err != nil { return err } - err = ioutil.WriteFile( + err = s.FS.WriteFile( filepath.Join(s.ConfigDir, "ThreadedNews.yaml"), out, 0666, @@ -349,15 +370,14 @@ func (s *Server) NewClientConn(conn io.ReadWriteCloser, remoteAddr string) *Clie clientConn := &ClientConn{ ID: &[]byte{0, 0}, - Icon: &[]byte{0, 0}, - Flags: &[]byte{0, 0}, + Icon: []byte{0, 0}, + Flags: []byte{0, 0}, UserName: []byte{}, Connection: conn, Server: s, - Version: &[]byte{}, + Version: []byte{}, AutoReply: []byte{}, transfers: map[int]map[[4]byte]*FileTransfer{}, - Agreed: false, RemoteAddr: remoteAddr, } clientConn.transfers = map[int]map[[4]byte]*FileTransfer{ @@ -378,7 +398,7 @@ func (s *Server) NewClientConn(conn io.ReadWriteCloser, remoteAddr string) *Clie } // NewUser creates a new user account entry in the server map and config file -func (s *Server) NewUser(login, name, password string, access []byte) error { +func (s *Server) NewUser(login, name, password string, access accessBitmap) error { s.mux.Lock() defer s.mux.Unlock() @@ -386,7 +406,7 @@ func (s *Server) NewUser(login, name, password string, access []byte) error { Login: login, Name: name, Password: hashAndSalt([]byte(password)), - Access: &access, + Access: access, } out, err := yaml.Marshal(&account) if err != nil { @@ -397,7 +417,7 @@ func (s *Server) NewUser(login, name, password string, access []byte) error { return s.FS.WriteFile(filepath.Join(s.ConfigDir, "Users", login+".yaml"), out, 0666) } -func (s *Server) UpdateUser(login, newLogin, name, password string, access []byte) error { +func (s *Server) UpdateUser(login, newLogin, name, password string, access accessBitmap) error { s.mux.Lock() defer s.mux.Unlock() @@ -412,7 +432,7 @@ func (s *Server) UpdateUser(login, newLogin, name, password string, access []byt } account := s.Accounts[newLogin] - account.Access = &access + account.Access = access account.Name = name account.Password = password @@ -444,20 +464,27 @@ func (s *Server) connectedUsers() []Field { var connectedUsers []Field for _, c := range sortedClients(s.Clients) { - if !c.Agreed { - continue - } user := User{ ID: *c.ID, - Icon: *c.Icon, - Flags: *c.Flags, + Icon: c.Icon, + Flags: c.Flags, Name: string(c.UserName), } - connectedUsers = append(connectedUsers, NewField(fieldUsernameWithInfo, user.Payload())) + connectedUsers = append(connectedUsers, NewField(FieldUsernameWithInfo, user.Payload())) } return connectedUsers } +func (s *Server) loadBanList(path string) error { + fh, err := os.Open(path) + if err != nil { + return err + } + decoder := yaml.NewDecoder(fh) + + return decoder.Decode(s.banList) +} + // loadThreadedNews loads the threaded news data from disk func (s *Server) loadThreadedNews(threadedNewsPath string) error { fh, err := os.Open(threadedNewsPath) @@ -517,48 +544,84 @@ func (s *Server) loadConfig(path string) error { return nil } -const ( - minTransactionLen = 22 // minimum length of any transaction -) - -// dontPanic recovers and logs panics instead of crashing -// TODO: remove this after known issues are fixed -func dontPanic(logger *zap.SugaredLogger) { - if r := recover(); r != nil { - fmt.Println("stacktrace from panic: \n" + string(debug.Stack())) - logger.Errorw("PANIC", "err", r, "trace", string(debug.Stack())) - } -} - // handleNewConnection takes a new net.Conn and performs the initial login sequence -func (s *Server) handleNewConnection(ctx context.Context, conn io.ReadWriteCloser, remoteAddr string) error { +func (s *Server) handleNewConnection(ctx context.Context, rwc io.ReadWriteCloser, remoteAddr string) error { defer dontPanic(s.Logger) - if err := Handshake(conn); err != nil { + if err := Handshake(rwc); err != nil { return err } - buf := make([]byte, 1024) - // TODO: fix potential short read with io.ReadFull - readLen, err := conn.Read(buf) - if readLen < minTransactionLen { - return err - } - if err != nil { + // Create a new scanner for parsing incoming bytes into transaction tokens + scanner := bufio.NewScanner(rwc) + scanner.Split(transactionScanner) + + scanner.Scan() + + // Make a new []byte slice and copy the scanner bytes to it. This is critical to avoid a data race as the + // scanner re-uses the buffer for subsequent scans. + buf := make([]byte, len(scanner.Bytes())) + copy(buf, scanner.Bytes()) + + var clientLogin Transaction + if _, err := clientLogin.Write(buf); err != nil { return err } - clientLogin, _, err := ReadTransaction(buf[:readLen]) - if err != nil { - return err + // check if remoteAddr is present in the ban list + if banUntil, ok := s.banList[strings.Split(remoteAddr, ":")[0]]; ok { + // permaban + if banUntil == nil { + t := NewTransaction( + TranServerMsg, + &[]byte{0, 0}, + NewField(FieldData, []byte("You are permanently banned on this server")), + NewField(FieldChatOptions, []byte{0, 0}), + ) + + b, err := t.MarshalBinary() + if err != nil { + return err + } + + _, err = rwc.Write(b) + if err != nil { + return err + } + + time.Sleep(1 * time.Second) + return nil + } + + // temporary ban + if time.Now().Before(*banUntil) { + t := NewTransaction( + TranServerMsg, + &[]byte{0, 0}, + NewField(FieldData, []byte("You are temporarily banned on this server")), + NewField(FieldChatOptions, []byte{0, 0}), + ) + b, err := t.MarshalBinary() + if err != nil { + return err + } + + _, err = rwc.Write(b) + if err != nil { + return err + } + + time.Sleep(1 * time.Second) + return nil + } } - c := s.NewClientConn(conn, remoteAddr) + c := s.NewClientConn(rwc, remoteAddr) defer c.Disconnect() - encodedLogin := clientLogin.GetField(fieldUserLogin).Data - encodedPassword := clientLogin.GetField(fieldUserPassword).Data - *c.Version = clientLogin.GetField(fieldVersion).Data + encodedLogin := clientLogin.GetField(FieldUserLogin).Data + encodedPassword := clientLogin.GetField(FieldUserPassword).Data + c.Version = clientLogin.GetField(FieldVersion).Data var login string for _, char := range encodedLogin { @@ -568,109 +631,120 @@ func (s *Server) handleNewConnection(ctx context.Context, conn io.ReadWriteClose login = GuestAccount } + c.logger = s.Logger.With("remoteAddr", remoteAddr, "login", login) + // If authentication fails, send error reply and close connection if !c.Authenticate(login, encodedPassword) { - t := c.NewErrReply(clientLogin, "Incorrect login.") + t := c.NewErrReply(&clientLogin, "Incorrect login.") b, err := t.MarshalBinary() if err != nil { return err } - if _, err := conn.Write(b); err != nil { + if _, err := rwc.Write(b); err != nil { return err } - return fmt.Errorf("incorrect login") - } - if clientLogin.GetField(fieldUserName).Data != nil { - c.UserName = clientLogin.GetField(fieldUserName).Data + c.logger.Infow("Login failed", "clientVersion", fmt.Sprintf("%x", c.Version)) + + return nil } - if clientLogin.GetField(fieldUserIconID).Data != nil { - *c.Icon = clientLogin.GetField(fieldUserIconID).Data + if clientLogin.GetField(FieldUserIconID).Data != nil { + c.Icon = clientLogin.GetField(FieldUserIconID).Data } c.Account = c.Server.Accounts[login] - if c.Authorize(accessDisconUser) { - *c.Flags = []byte{0, 2} + if clientLogin.GetField(FieldUserName).Data != nil { + if c.Authorize(accessAnyName) { + c.UserName = clientLogin.GetField(FieldUserName).Data + } else { + c.UserName = []byte(c.Account.Name) + } } - c.logger = s.Logger.With("remoteAddr", remoteAddr, "login", login) - - c.logger.Infow("Client connection received", "version", fmt.Sprintf("%x", *c.Version)) + if c.Authorize(accessDisconUser) { + c.Flags = []byte{0, 2} + } - s.outbox <- c.NewReply(clientLogin, - NewField(fieldVersion, []byte{0x00, 0xbe}), - NewField(fieldCommunityBannerID, []byte{0, 0}), - NewField(fieldServerName, []byte(s.Config.Name)), + s.outbox <- c.NewReply(&clientLogin, + NewField(FieldVersion, []byte{0x00, 0xbe}), + NewField(FieldCommunityBannerID, []byte{0, 0}), + NewField(FieldServerName, []byte(s.Config.Name)), ) // Send user access privs so client UI knows how to behave - c.Server.outbox <- *NewTransaction(tranUserAccess, c.ID, NewField(fieldUserAccess, *c.Account.Access)) - - // Show agreement to client - c.Server.outbox <- *NewTransaction(tranShowAgreement, c.ID, NewField(fieldData, s.Agreement)) + c.Server.outbox <- *NewTransaction(TranUserAccess, c.ID, NewField(FieldUserAccess, c.Account.Access[:])) + + // Accounts with accessNoAgreement do not receive the server agreement on login. The behavior is different between + // client versions. For 1.2.3 client, we do not send TranShowAgreement. For other client versions, we send + // TranShowAgreement but with the NoServerAgreement field set to 1. + if c.Authorize(accessNoAgreement) { + // If client version is nil, then the client uses the 1.2.3 login behavior + if c.Version != nil { + c.Server.outbox <- *NewTransaction(TranShowAgreement, c.ID, NewField(FieldNoServerAgreement, []byte{1})) + } + } else { + c.Server.outbox <- *NewTransaction(TranShowAgreement, c.ID, NewField(FieldData, s.Agreement)) + } - // Used simplified hotline v1.2.3 login flow for clients that do not send login info in tranAgreed - if *c.Version == nil || bytes.Equal(*c.Version, nostalgiaVersion) { - c.Agreed = true + // If the client has provided a username as part of the login, we can infer that it is using the 1.2.3 login + // flow and not the 1.5+ flow. + if len(c.UserName) != 0 { + // Add the client username to the logger. For 1.5+ clients, we don't have this information yet as it comes as + // part of TranAgreed c.logger = c.logger.With("name", string(c.UserName)) + c.logger.Infow("Login successful", "clientVersion", "Not sent (probably 1.2.3)") + + // Notify other clients on the server that the new user has logged in. For 1.5+ clients we don't have this + // information yet, so we do it in TranAgreed instead for _, t := range c.notifyOthers( *NewTransaction( - tranNotifyChangeUser, nil, - NewField(fieldUserName, c.UserName), - NewField(fieldUserID, *c.ID), - NewField(fieldUserIconID, *c.Icon), - NewField(fieldUserFlags, *c.Flags), + TranNotifyChangeUser, nil, + NewField(FieldUserName, c.UserName), + NewField(FieldUserID, *c.ID), + NewField(FieldUserIconID, c.Icon), + NewField(FieldUserFlags, c.Flags), ), ) { c.Server.outbox <- t } } - c.Server.Stats.LoginCount += 1 + c.Server.Stats.ConnectionCounter += 1 + if len(s.Clients) > c.Server.Stats.ConnectionPeak { + c.Server.Stats.ConnectionPeak = len(s.Clients) + } - const readBuffSize = 1024000 // 1KB - TODO: what should this be? - tranBuff := make([]byte, 0) - tReadlen := 0 - // Infinite loop where take action on incoming client requests until the connection is closed - for { - buf = make([]byte, readBuffSize) - tranBuff = tranBuff[tReadlen:] + // Scan for new transactions and handle them as they come in. + for scanner.Scan() { + // Make a new []byte slice and copy the scanner bytes to it. This is critical to avoid a data race as the + // scanner re-uses the buffer for subsequent scans. + buf := make([]byte, len(scanner.Bytes())) + copy(buf, scanner.Bytes()) - readLen, err := c.Connection.Read(buf) - if err != nil { + var t Transaction + if _, err := t.Write(buf); err != nil { return err } - tranBuff = append(tranBuff, buf[:readLen]...) - // We may have read multiple requests worth of bytes from Connection.Read. readTransactions splits them - // into a slice of transactions - var transactions []Transaction - if transactions, tReadlen, err = readTransactions(tranBuff); err != nil { + if err := c.handleTransaction(t); err != nil { c.logger.Errorw("Error handling transaction", "err", err) } - - // iterate over all the transactions that were parsed from the byte slice and handle them - for _, t := range transactions { - if err := c.handleTransaction(&t); err != nil { - c.logger.Errorw("Error handling transaction", "err", err) - } - } } + return nil } func (s *Server) NewPrivateChat(cc *ClientConn) []byte { - s.mux.Lock() - defer s.mux.Unlock() + s.PrivateChatsMu.Lock() + defer s.PrivateChatsMu.Unlock() randID := make([]byte, 4) rand.Read(randID) - data := binary.BigEndian.Uint32(randID[:]) + data := binary.BigEndian.Uint32(randID) s.PrivateChats[data] = &PrivateChat{ - Subject: "", ClientConn: make(map[uint16]*ClientConn), } s.PrivateChats[data].ClientConn[cc.uint16ID()] = cc @@ -701,6 +775,10 @@ func (s *Server) handleFileTransfer(ctx context.Context, rwc io.ReadWriter) erro delete(s.fileTransfers, t.ReferenceNumber) s.mux.Unlock() + // Wait a few seconds before closing the connection: this is a workaround for problems + // observed with Windows clients where the client must initiate close of the TCP connection before + // the server does. This is gross and seems unnecessary. TODO: Revisit? + time.Sleep(3 * time.Second) }() s.mux.Lock() @@ -730,11 +808,14 @@ func (s *Server) handleFileTransfer(ctx context.Context, rwc io.ReadWriter) erro switch fileTransfer.Type { case bannerDownload: if err := s.bannerDownload(rwc); err != nil { - panic(err) return err } case FileDownload: s.Stats.DownloadCounter += 1 + s.Stats.DownloadsInProgress += 1 + defer func() { + s.Stats.DownloadsInProgress -= 1 + }() var dataOffset int64 if fileTransfer.fileResumeData != nil { @@ -789,6 +870,8 @@ func (s *Server) handleFileTransfer(ctx context.Context, rwc io.ReadWriter) erro case FileUpload: s.Stats.UploadCounter += 1 + s.Stats.UploadsInProgress += 1 + defer func() { s.Stats.UploadsInProgress -= 1 }() var file *os.File @@ -845,7 +928,12 @@ func (s *Server) handleFileTransfer(ctx context.Context, rwc io.ReadWriter) erro } rLogger.Infow("File upload complete", "dstFile", fullPath) + case FolderDownload: + s.Stats.DownloadCounter += 1 + s.Stats.DownloadsInProgress += 1 + defer func() { s.Stats.DownloadsInProgress -= 1 }() + // Folder Download flow: // 1. Get filePath from the transfer // 2. Iterate over files @@ -1009,6 +1097,9 @@ func (s *Server) handleFileTransfer(ctx context.Context, rwc io.ReadWriter) erro } case FolderUpload: + s.Stats.UploadCounter += 1 + s.Stats.UploadsInProgress += 1 + defer func() { s.Stats.UploadsInProgress -= 1 }() rLogger.Infow( "Folder upload started", "dstPath", fullPath, @@ -1120,7 +1211,7 @@ func (s *Server) handleFileTransfer(ctx context.Context, rwc io.ReadWriter) erro return err } - if err := receiveFile(rwc, file, ioutil.Discard, ioutil.Discard, fileTransfer.bytesSentCounter); err != nil { + if err := receiveFile(rwc, file, io.Discard, io.Discard, fileTransfer.bytesSentCounter); err != nil { s.Logger.Error(err) }