git.r.bdr.sh - rbdr/mobius/blob - hotline/server.go

   1 package hotline
   2
   3 import (
   4         "bufio"
   5         "context"
   6         "encoding/binary"
   7         "errors"
   8         "fmt"
   9         "github.com/go-playground/validator/v10"
  10         "go.uber.org/zap"
  11         "gopkg.in/yaml.v3"
  12         "io"
  13         "io/fs"
  14         "math/big"
  15         "math/rand"
  16         "net"
  17         "os"
  18         "path/filepath"
  19         "strings"
  20         "sync"
  21         "time"
  22 )
  23
  24 type contextKey string
  25
  26 var contextKeyReq = contextKey("req")
  27
  28 type requestCtx struct {
  29         remoteAddr string
  30 }
  31
  32 type Server struct {
  33         NetInterface  string
  34         Port          int
  35         Accounts      map[string]*Account
  36         Agreement     []byte
  37         Clients       map[uint16]*ClientConn
  38         fileTransfers map[[4]byte]*FileTransfer
  39
  40         Config    *Config
  41         ConfigDir string
  42         Logger    *zap.SugaredLogger
  43
  44         PrivateChatsMu sync.Mutex
  45         PrivateChats   map[uint32]*PrivateChat
  46
  47         NextGuestID   *uint16
  48         TrackerPassID [4]byte
  49
  50         StatsMu sync.Mutex
  51         Stats   *Stats
  52
  53         FS FileStore // Storage backend to use for File storage
  54
  55         outbox chan Transaction
  56         mux    sync.Mutex
  57
  58         threadedNewsMux sync.Mutex
  59         ThreadedNews    *ThreadedNews
  60
  61         flatNewsMux sync.Mutex
  62         FlatNews    []byte
  63
  64         banListMU sync.Mutex
  65         banList   map[string]*time.Time
  66 }
  67
  68 func (s *Server) CurrentStats() Stats {
  69         s.StatsMu.Lock()
  70         defer s.StatsMu.Unlock()
  71
  72         stats := s.Stats
  73         stats.CurrentlyConnected = len(s.Clients)
  74
  75         return *stats
  76 }
  77
  78 type PrivateChat struct {
  79         Subject    string
  80         ClientConn map[uint16]*ClientConn
  81 }
  82
  83 func (s *Server) ListenAndServe(ctx context.Context, cancelRoot context.CancelFunc) error {
  84         s.Logger.Infow("Hotline server started",
  85                 "version", VERSION,
  86                 "API port", fmt.Sprintf("%s:%v", s.NetInterface, s.Port),
  87                 "Transfer port", fmt.Sprintf("%s:%v", s.NetInterface, s.Port+1),
  88         )
  89
  90         var wg sync.WaitGroup
  91
  92         wg.Add(1)
  93         go func() {
  94                 ln, err := net.Listen("tcp", fmt.Sprintf("%s:%v", s.NetInterface, s.Port))
  95                 if err != nil {
  96                         s.Logger.Fatal(err)
  97                 }
  98
  99                 s.Logger.Fatal(s.Serve(ctx, ln))
 100         }()
 101
 102         wg.Add(1)
 103         go func() {
 104                 ln, err := net.Listen("tcp", fmt.Sprintf("%s:%v", s.NetInterface, s.Port+1))
 105                 if err != nil {
 106                         s.Logger.Fatal(err)
 107                 }
 108
 109                 s.Logger.Fatal(s.ServeFileTransfers(ctx, ln))
 110         }()
 111
 112         wg.Wait()
 113
 114         return nil
 115 }
 116
 117 func (s *Server) ServeFileTransfers(ctx context.Context, ln net.Listener) error {
 118         for {
 119                 conn, err := ln.Accept()
 120                 if err != nil {
 121                         return err
 122                 }
 123
 124                 go func() {
 125                         defer func() { _ = conn.Close() }()
 126
 127                         err = s.handleFileTransfer(
 128                                 context.WithValue(ctx, contextKeyReq, requestCtx{
 129                                         remoteAddr: conn.RemoteAddr().String(),
 130                                 }),
 131                                 conn,
 132                         )
 133
 134                         if err != nil {
 135                                 s.Logger.Errorw("file transfer error", "reason", err)
 136                         }
 137                 }()
 138         }
 139 }
 140
 141 func (s *Server) sendTransaction(t Transaction) error {
 142         clientID, err := byteToInt(*t.clientID)
 143         if err != nil {
 144                 return err
 145         }
 146
 147         s.mux.Lock()
 148         client := s.Clients[uint16(clientID)]
 149         s.mux.Unlock()
 150         if client == nil {
 151                 return fmt.Errorf("invalid client id %v", *t.clientID)
 152         }
 153
 154         b, err := t.MarshalBinary()
 155         if err != nil {
 156                 return err
 157         }
 158
 159         _, err = client.Connection.Write(b)
 160         if err != nil {
 161                 return err
 162         }
 163
 164         return nil
 165 }
 166
 167 func (s *Server) processOutbox() {
 168         for {
 169                 t := <-s.outbox
 170                 go func() {
 171                         if err := s.sendTransaction(t); err != nil {
 172                                 s.Logger.Errorw("error sending transaction", "err", err)
 173                         }
 174                 }()
 175         }
 176 }
 177
 178 func (s *Server) Serve(ctx context.Context, ln net.Listener) error {
 179         go s.processOutbox()
 180
 181         for {
 182                 conn, err := ln.Accept()
 183                 if err != nil {
 184                         s.Logger.Errorw("error accepting connection", "err", err)
 185                 }
 186                 connCtx := context.WithValue(ctx, contextKeyReq, requestCtx{
 187                         remoteAddr: conn.RemoteAddr().String(),
 188                 })
 189
 190                 go func() {
 191                         s.Logger.Infow("Connection established", "RemoteAddr", conn.RemoteAddr())
 192
 193                         defer conn.Close()
 194                         if err := s.handleNewConnection(connCtx, conn, conn.RemoteAddr().String()); err != nil {
 195                                 if err == io.EOF {
 196                                         s.Logger.Infow("Client disconnected", "RemoteAddr", conn.RemoteAddr())
 197                                 } else {
 198                                         s.Logger.Errorw("error serving request", "RemoteAddr", conn.RemoteAddr(), "err", err)
 199                                 }
 200                         }
 201                 }()
 202         }
 203 }
 204
 205 const (
 206         agreementFile = "Agreement.txt"
 207 )
 208
 209 // NewServer constructs a new Server from a config dir
 210 func NewServer(configDir, netInterface string, netPort int, logger *zap.SugaredLogger, fs FileStore) (*Server, error) {
 211         server := Server{
 212                 NetInterface:  netInterface,
 213                 Port:          netPort,
 214                 Accounts:      make(map[string]*Account),
 215                 Config:        new(Config),
 216                 Clients:       make(map[uint16]*ClientConn),
 217                 fileTransfers: make(map[[4]byte]*FileTransfer),
 218                 PrivateChats:  make(map[uint32]*PrivateChat),
 219                 ConfigDir:     configDir,
 220                 Logger:        logger,
 221                 NextGuestID:   new(uint16),
 222                 outbox:        make(chan Transaction),
 223                 Stats:         &Stats{Since: time.Now()},
 224                 ThreadedNews:  &ThreadedNews{},
 225                 FS:            fs,
 226                 banList:       make(map[string]*time.Time),
 227         }
 228
 229         var err error
 230
 231         // generate a new random passID for tracker registration
 232         if _, err := rand.Read(server.TrackerPassID[:]); err != nil {
 233                 return nil, err
 234         }
 235
 236         server.Agreement, err = os.ReadFile(filepath.Join(configDir, agreementFile))
 237         if err != nil {
 238                 return nil, err
 239         }
 240
 241         if server.FlatNews, err = os.ReadFile(filepath.Join(configDir, "MessageBoard.txt")); err != nil {
 242                 return nil, err
 243         }
 244
 245         // try to load the ban list, but ignore errors as this file may not be present or may be empty
 246         _ = server.loadBanList(filepath.Join(configDir, "Banlist.yaml"))
 247
 248         if err := server.loadThreadedNews(filepath.Join(configDir, "ThreadedNews.yaml")); err != nil {
 249                 return nil, err
 250         }
 251
 252         if err := server.loadConfig(filepath.Join(configDir, "config.yaml")); err != nil {
 253                 return nil, err
 254         }
 255
 256         if err := server.loadAccounts(filepath.Join(configDir, "Users/")); err != nil {
 257                 return nil, err
 258         }
 259
 260         // If the FileRoot is an absolute path, use it, otherwise treat as a relative path to the config dir.
 261         if !filepath.IsAbs(server.Config.FileRoot) {
 262                 server.Config.FileRoot = filepath.Join(configDir, server.Config.FileRoot)
 263         }
 264
 265         *server.NextGuestID = 1
 266
 267         if server.Config.EnableTrackerRegistration {
 268                 server.Logger.Infow(
 269                         "Tracker registration enabled",
 270                         "frequency", fmt.Sprintf("%vs", trackerUpdateFrequency),
 271                         "trackers", server.Config.Trackers,
 272                 )
 273
 274                 go func() {
 275                         for {
 276                                 tr := &TrackerRegistration{
 277                                         UserCount:   server.userCount(),
 278                                         PassID:      server.TrackerPassID[:],
 279                                         Name:        server.Config.Name,
 280                                         Description: server.Config.Description,
 281                                 }
 282                                 binary.BigEndian.PutUint16(tr.Port[:], uint16(server.Port))
 283                                 for _, t := range server.Config.Trackers {
 284                                         if err := register(t, tr); err != nil {
 285                                                 server.Logger.Errorw("unable to register with tracker %v", "error", err)
 286                                         }
 287                                         server.Logger.Debugw("Sent Tracker registration", "addr", t)
 288                                 }
 289
 290                                 time.Sleep(trackerUpdateFrequency * time.Second)
 291                         }
 292                 }()
 293         }
 294
 295         // Start Client Keepalive go routine
 296         go server.keepaliveHandler()
 297
 298         return &server, nil
 299 }
 300
 301 func (s *Server) userCount() int {
 302         s.mux.Lock()
 303         defer s.mux.Unlock()
 304
 305         return len(s.Clients)
 306 }
 307
 308 func (s *Server) keepaliveHandler() {
 309         for {
 310                 time.Sleep(idleCheckInterval * time.Second)
 311                 s.mux.Lock()
 312
 313                 for _, c := range s.Clients {
 314                         c.IdleTime += idleCheckInterval
 315                         if c.IdleTime > userIdleSeconds && !c.Idle {
 316                                 c.Idle = true
 317
 318                                 flagBitmap := big.NewInt(int64(binary.BigEndian.Uint16(c.Flags)))
 319                                 flagBitmap.SetBit(flagBitmap, UserFlagAway, 1)
 320                                 binary.BigEndian.PutUint16(c.Flags, uint16(flagBitmap.Int64()))
 321
 322                                 c.sendAll(
 323                                         TranNotifyChangeUser,
 324                                         NewField(FieldUserID, *c.ID),
 325                                         NewField(FieldUserFlags, c.Flags),
 326                                         NewField(FieldUserName, c.UserName),
 327                                         NewField(FieldUserIconID, c.Icon),
 328                                 )
 329                         }
 330                 }
 331                 s.mux.Unlock()
 332         }
 333 }
 334
 335 func (s *Server) writeBanList() error {
 336         s.banListMU.Lock()
 337         defer s.banListMU.Unlock()
 338
 339         out, err := yaml.Marshal(s.banList)
 340         if err != nil {
 341                 return err
 342         }
 343         err = os.WriteFile(
 344                 filepath.Join(s.ConfigDir, "Banlist.yaml"),
 345                 out,
 346                 0666,
 347         )
 348         return err
 349 }
 350
 351 func (s *Server) writeThreadedNews() error {
 352         s.threadedNewsMux.Lock()
 353         defer s.threadedNewsMux.Unlock()
 354
 355         out, err := yaml.Marshal(s.ThreadedNews)
 356         if err != nil {
 357                 return err
 358         }
 359         err = s.FS.WriteFile(
 360                 filepath.Join(s.ConfigDir, "ThreadedNews.yaml"),
 361                 out,
 362                 0666,
 363         )
 364         return err
 365 }
 366
 367 func (s *Server) NewClientConn(conn io.ReadWriteCloser, remoteAddr string) *ClientConn {
 368         s.mux.Lock()
 369         defer s.mux.Unlock()
 370
 371         clientConn := &ClientConn{
 372                 ID:         &[]byte{0, 0},
 373                 Icon:       []byte{0, 0},
 374                 Flags:      []byte{0, 0},
 375                 UserName:   []byte{},
 376                 Connection: conn,
 377                 Server:     s,
 378                 Version:    []byte{},
 379                 AutoReply:  []byte{},
 380                 transfers:  map[int]map[[4]byte]*FileTransfer{},
 381                 RemoteAddr: remoteAddr,
 382         }
 383         clientConn.transfers = map[int]map[[4]byte]*FileTransfer{
 384                 FileDownload:   {},
 385                 FileUpload:     {},
 386                 FolderDownload: {},
 387                 FolderUpload:   {},
 388                 bannerDownload: {},
 389         }
 390
 391         *s.NextGuestID++
 392         ID := *s.NextGuestID
 393
 394         binary.BigEndian.PutUint16(*clientConn.ID, ID)
 395         s.Clients[ID] = clientConn
 396
 397         return clientConn
 398 }
 399
 400 // NewUser creates a new user account entry in the server map and config file
 401 func (s *Server) NewUser(login, name, password string, access accessBitmap) error {
 402         s.mux.Lock()
 403         defer s.mux.Unlock()
 404
 405         account := Account{
 406                 Login:    login,
 407                 Name:     name,
 408                 Password: hashAndSalt([]byte(password)),
 409                 Access:   access,
 410         }
 411         out, err := yaml.Marshal(&account)
 412         if err != nil {
 413                 return err
 414         }
 415         s.Accounts[login] = &account
 416
 417         return s.FS.WriteFile(filepath.Join(s.ConfigDir, "Users", login+".yaml"), out, 0666)
 418 }
 419
 420 func (s *Server) UpdateUser(login, newLogin, name, password string, access accessBitmap) error {
 421         s.mux.Lock()
 422         defer s.mux.Unlock()
 423
 424         // update renames the user login
 425         if login != newLogin {
 426                 err := os.Rename(filepath.Join(s.ConfigDir, "Users", login+".yaml"), filepath.Join(s.ConfigDir, "Users", newLogin+".yaml"))
 427                 if err != nil {
 428                         return err
 429                 }
 430                 s.Accounts[newLogin] = s.Accounts[login]
 431                 delete(s.Accounts, login)
 432         }
 433
 434         account := s.Accounts[newLogin]
 435         account.Access = access
 436         account.Name = name
 437         account.Password = password
 438
 439         out, err := yaml.Marshal(&account)
 440         if err != nil {
 441                 return err
 442         }
 443
 444         if err := os.WriteFile(filepath.Join(s.ConfigDir, "Users", newLogin+".yaml"), out, 0666); err != nil {
 445                 return err
 446         }
 447
 448         return nil
 449 }
 450
 451 // DeleteUser deletes the user account
 452 func (s *Server) DeleteUser(login string) error {
 453         s.mux.Lock()
 454         defer s.mux.Unlock()
 455
 456         delete(s.Accounts, login)
 457
 458         return s.FS.Remove(filepath.Join(s.ConfigDir, "Users", login+".yaml"))
 459 }
 460
 461 func (s *Server) connectedUsers() []Field {
 462         s.mux.Lock()
 463         defer s.mux.Unlock()
 464
 465         var connectedUsers []Field
 466         for _, c := range sortedClients(s.Clients) {
 467                 user := User{
 468                         ID:    *c.ID,
 469                         Icon:  c.Icon,
 470                         Flags: c.Flags,
 471                         Name:  string(c.UserName),
 472                 }
 473                 connectedUsers = append(connectedUsers, NewField(FieldUsernameWithInfo, user.Payload()))
 474         }
 475         return connectedUsers
 476 }
 477
 478 func (s *Server) loadBanList(path string) error {
 479         fh, err := os.Open(path)
 480         if err != nil {
 481                 return err
 482         }
 483         decoder := yaml.NewDecoder(fh)
 484
 485         return decoder.Decode(s.banList)
 486 }
 487
 488 // loadThreadedNews loads the threaded news data from disk
 489 func (s *Server) loadThreadedNews(threadedNewsPath string) error {
 490         fh, err := os.Open(threadedNewsPath)
 491         if err != nil {
 492                 return err
 493         }
 494         decoder := yaml.NewDecoder(fh)
 495
 496         return decoder.Decode(s.ThreadedNews)
 497 }
 498
 499 // loadAccounts loads account data from disk
 500 func (s *Server) loadAccounts(userDir string) error {
 501         matches, err := filepath.Glob(filepath.Join(userDir, "*.yaml"))
 502         if err != nil {
 503                 return err
 504         }
 505
 506         if len(matches) == 0 {
 507                 return errors.New("no user accounts found in " + userDir)
 508         }
 509
 510         for _, file := range matches {
 511                 fh, err := s.FS.Open(file)
 512                 if err != nil {
 513                         return err
 514                 }
 515
 516                 account := Account{}
 517                 decoder := yaml.NewDecoder(fh)
 518                 if err := decoder.Decode(&account); err != nil {
 519                         return err
 520                 }
 521
 522                 s.Accounts[account.Login] = &account
 523         }
 524         return nil
 525 }
 526
 527 func (s *Server) loadConfig(path string) error {
 528         fh, err := s.FS.Open(path)
 529         if err != nil {
 530                 return err
 531         }
 532
 533         decoder := yaml.NewDecoder(fh)
 534         err = decoder.Decode(s.Config)
 535         if err != nil {
 536                 return err
 537         }
 538
 539         validate := validator.New()
 540         err = validate.Struct(s.Config)
 541         if err != nil {
 542                 return err
 543         }
 544         return nil
 545 }
 546
 547 // handleNewConnection takes a new net.Conn and performs the initial login sequence
 548 func (s *Server) handleNewConnection(ctx context.Context, rwc io.ReadWriteCloser, remoteAddr string) error {
 549         defer dontPanic(s.Logger)
 550
 551         if err := Handshake(rwc); err != nil {
 552                 return err
 553         }
 554
 555         // Create a new scanner for parsing incoming bytes into transaction tokens
 556         scanner := bufio.NewScanner(rwc)
 557         scanner.Split(transactionScanner)
 558
 559         scanner.Scan()
 560
 561         // Make a new []byte slice and copy the scanner bytes to it.  This is critical to avoid a data race as the
 562         // scanner re-uses the buffer for subsequent scans.
 563         buf := make([]byte, len(scanner.Bytes()))
 564         copy(buf, scanner.Bytes())
 565
 566         var clientLogin Transaction
 567         if _, err := clientLogin.Write(buf); err != nil {
 568                 return err
 569         }
 570
 571         // check if remoteAddr is present in the ban list
 572         if banUntil, ok := s.banList[strings.Split(remoteAddr, ":")[0]]; ok {
 573                 // permaban
 574                 if banUntil == nil {
 575                         t := NewTransaction(
 576                                 TranServerMsg,
 577                                 &[]byte{0, 0},
 578                                 NewField(FieldData, []byte("You are permanently banned on this server")),
 579                                 NewField(FieldChatOptions, []byte{0, 0}),
 580                         )
 581
 582                         b, err := t.MarshalBinary()
 583                         if err != nil {
 584                                 return err
 585                         }
 586
 587                         _, err = rwc.Write(b)
 588                         if err != nil {
 589                                 return err
 590                         }
 591
 592                         time.Sleep(1 * time.Second)
 593                         return nil
 594                 }
 595
 596                 // temporary ban
 597                 if time.Now().Before(*banUntil) {
 598                         t := NewTransaction(
 599                                 TranServerMsg,
 600                                 &[]byte{0, 0},
 601                                 NewField(FieldData, []byte("You are temporarily banned on this server")),
 602                                 NewField(FieldChatOptions, []byte{0, 0}),
 603                         )
 604                         b, err := t.MarshalBinary()
 605                         if err != nil {
 606                                 return err
 607                         }
 608
 609                         _, err = rwc.Write(b)
 610                         if err != nil {
 611                                 return err
 612                         }
 613
 614                         time.Sleep(1 * time.Second)
 615                         return nil
 616                 }
 617         }
 618
 619         c := s.NewClientConn(rwc, remoteAddr)
 620         defer c.Disconnect()
 621
 622         encodedLogin := clientLogin.GetField(FieldUserLogin).Data
 623         encodedPassword := clientLogin.GetField(FieldUserPassword).Data
 624         c.Version = clientLogin.GetField(FieldVersion).Data
 625
 626         var login string
 627         for _, char := range encodedLogin {
 628                 login += string(rune(255 - uint(char)))
 629         }
 630         if login == "" {
 631                 login = GuestAccount
 632         }
 633
 634         c.logger = s.Logger.With("remoteAddr", remoteAddr, "login", login)
 635
 636         // If authentication fails, send error reply and close connection
 637         if !c.Authenticate(login, encodedPassword) {
 638                 t := c.NewErrReply(&clientLogin, "Incorrect login.")
 639                 b, err := t.MarshalBinary()
 640                 if err != nil {
 641                         return err
 642                 }
 643                 if _, err := rwc.Write(b); err != nil {
 644                         return err
 645                 }
 646
 647                 c.logger.Infow("Login failed", "clientVersion", fmt.Sprintf("%x", c.Version))
 648
 649                 return nil
 650         }
 651
 652         if clientLogin.GetField(FieldUserIconID).Data != nil {
 653                 c.Icon = clientLogin.GetField(FieldUserIconID).Data
 654         }
 655
 656         c.Account = c.Server.Accounts[login]
 657
 658         if clientLogin.GetField(FieldUserName).Data != nil {
 659                 if c.Authorize(accessAnyName) {
 660                         c.UserName = clientLogin.GetField(FieldUserName).Data
 661                 } else {
 662                         c.UserName = []byte(c.Account.Name)
 663                 }
 664         }
 665
 666         if c.Authorize(accessDisconUser) {
 667                 c.Flags = []byte{0, 2}
 668         }
 669
 670         s.outbox <- c.NewReply(&clientLogin,
 671                 NewField(FieldVersion, []byte{0x00, 0xbe}),
 672                 NewField(FieldCommunityBannerID, []byte{0, 0}),
 673                 NewField(FieldServerName, []byte(s.Config.Name)),
 674         )
 675
 676         // Send user access privs so client UI knows how to behave
 677         c.Server.outbox <- *NewTransaction(TranUserAccess, c.ID, NewField(FieldUserAccess, c.Account.Access[:]))
 678
 679         // Accounts with accessNoAgreement do not receive the server agreement on login.  The behavior is different between
 680         // client versions.  For 1.2.3 client, we do not send TranShowAgreement.  For other client versions, we send
 681         // TranShowAgreement but with the NoServerAgreement field set to 1.
 682         if c.Authorize(accessNoAgreement) {
 683                 // If client version is nil, then the client uses the 1.2.3 login behavior
 684                 if c.Version != nil {
 685                         c.Server.outbox <- *NewTransaction(TranShowAgreement, c.ID, NewField(FieldNoServerAgreement, []byte{1}))
 686                 }
 687         } else {
 688                 c.Server.outbox <- *NewTransaction(TranShowAgreement, c.ID, NewField(FieldData, s.Agreement))
 689         }
 690
 691         // If the client has provided a username as part of the login, we can infer that it is using the 1.2.3 login
 692         // flow and not the 1.5+ flow.
 693         if len(c.UserName) != 0 {
 694                 // Add the client username to the logger.  For 1.5+ clients, we don't have this information yet as it comes as
 695                 // part of TranAgreed
 696                 c.logger = c.logger.With("name", string(c.UserName))
 697
 698                 c.logger.Infow("Login successful", "clientVersion", "Not sent (probably 1.2.3)")
 699
 700                 // Notify other clients on the server that the new user has logged in.  For 1.5+ clients we don't have this
 701                 // information yet, so we do it in TranAgreed instead
 702                 for _, t := range c.notifyOthers(
 703                         *NewTransaction(
 704                                 TranNotifyChangeUser, nil,
 705                                 NewField(FieldUserName, c.UserName),
 706                                 NewField(FieldUserID, *c.ID),
 707                                 NewField(FieldUserIconID, c.Icon),
 708                                 NewField(FieldUserFlags, c.Flags),
 709                         ),
 710                 ) {
 711                         c.Server.outbox <- t
 712                 }
 713         }
 714
 715         c.Server.Stats.ConnectionCounter += 1
 716         if len(s.Clients) > c.Server.Stats.ConnectionPeak {
 717                 c.Server.Stats.ConnectionPeak = len(s.Clients)
 718         }
 719
 720         // Scan for new transactions and handle them as they come in.
 721         for scanner.Scan() {
 722                 // Make a new []byte slice and copy the scanner bytes to it.  This is critical to avoid a data race as the
 723                 // scanner re-uses the buffer for subsequent scans.
 724                 buf := make([]byte, len(scanner.Bytes()))
 725                 copy(buf, scanner.Bytes())
 726
 727                 var t Transaction
 728                 if _, err := t.Write(buf); err != nil {
 729                         return err
 730                 }
 731
 732                 if err := c.handleTransaction(t); err != nil {
 733                         c.logger.Errorw("Error handling transaction", "err", err)
 734                 }
 735         }
 736         return nil
 737 }
 738
 739 func (s *Server) NewPrivateChat(cc *ClientConn) []byte {
 740         s.PrivateChatsMu.Lock()
 741         defer s.PrivateChatsMu.Unlock()
 742
 743         randID := make([]byte, 4)
 744         rand.Read(randID)
 745         data := binary.BigEndian.Uint32(randID)
 746
 747         s.PrivateChats[data] = &PrivateChat{
 748                 ClientConn: make(map[uint16]*ClientConn),
 749         }
 750         s.PrivateChats[data].ClientConn[cc.uint16ID()] = cc
 751
 752         return randID
 753 }
 754
 755 const dlFldrActionSendFile = 1
 756 const dlFldrActionResumeFile = 2
 757 const dlFldrActionNextFile = 3
 758
 759 // handleFileTransfer receives a client net.Conn from the file transfer server, performs the requested transfer type, then closes the connection
 760 func (s *Server) handleFileTransfer(ctx context.Context, rwc io.ReadWriter) error {
 761         defer dontPanic(s.Logger)
 762
 763         txBuf := make([]byte, 16)
 764         if _, err := io.ReadFull(rwc, txBuf); err != nil {
 765                 return err
 766         }
 767
 768         var t transfer
 769         if _, err := t.Write(txBuf); err != nil {
 770                 return err
 771         }
 772
 773         defer func() {
 774                 s.mux.Lock()
 775                 delete(s.fileTransfers, t.ReferenceNumber)
 776                 s.mux.Unlock()
 777
 778                 // Wait a few seconds before closing the connection: this is a workaround for problems
 779                 // observed with Windows clients where the client must initiate close of the TCP connection before
 780                 // the server does.  This is gross and seems unnecessary.  TODO: Revisit?
 781                 time.Sleep(3 * time.Second)
 782         }()
 783
 784         s.mux.Lock()
 785         fileTransfer, ok := s.fileTransfers[t.ReferenceNumber]
 786         s.mux.Unlock()
 787         if !ok {
 788                 return errors.New("invalid transaction ID")
 789         }
 790
 791         defer func() {
 792                 fileTransfer.ClientConn.transfersMU.Lock()
 793                 delete(fileTransfer.ClientConn.transfers[fileTransfer.Type], t.ReferenceNumber)
 794                 fileTransfer.ClientConn.transfersMU.Unlock()
 795         }()
 796
 797         rLogger := s.Logger.With(
 798                 "remoteAddr", ctx.Value(contextKeyReq).(requestCtx).remoteAddr,
 799                 "login", fileTransfer.ClientConn.Account.Login,
 800                 "name", string(fileTransfer.ClientConn.UserName),
 801         )
 802
 803         fullPath, err := readPath(s.Config.FileRoot, fileTransfer.FilePath, fileTransfer.FileName)
 804         if err != nil {
 805                 return err
 806         }
 807
 808         switch fileTransfer.Type {
 809         case bannerDownload:
 810                 if err := s.bannerDownload(rwc); err != nil {
 811                         return err
 812                 }
 813         case FileDownload:
 814                 s.Stats.DownloadCounter += 1
 815                 s.Stats.DownloadsInProgress += 1
 816                 defer func() {
 817                         s.Stats.DownloadsInProgress -= 1
 818                 }()
 819
 820                 var dataOffset int64
 821                 if fileTransfer.fileResumeData != nil {
 822                         dataOffset = int64(binary.BigEndian.Uint32(fileTransfer.fileResumeData.ForkInfoList[0].DataSize[:]))
 823                 }
 824
 825                 fw, err := newFileWrapper(s.FS, fullPath, 0)
 826                 if err != nil {
 827                         return err
 828                 }
 829
 830                 rLogger.Infow("File download started", "filePath", fullPath)
 831
 832                 // if file transfer options are included, that means this is a "quick preview" request from a 1.5+ client
 833                 if fileTransfer.options == nil {
 834                         // Start by sending flat file object to client
 835                         if _, err := rwc.Write(fw.ffo.BinaryMarshal()); err != nil {
 836                                 return err
 837                         }
 838                 }
 839
 840                 file, err := fw.dataForkReader()
 841                 if err != nil {
 842                         return err
 843                 }
 844
 845                 br := bufio.NewReader(file)
 846                 if _, err := br.Discard(int(dataOffset)); err != nil {
 847                         return err
 848                 }
 849
 850                 if _, err = io.Copy(rwc, io.TeeReader(br, fileTransfer.bytesSentCounter)); err != nil {
 851                         return err
 852                 }
 853
 854                 // if the client requested to resume transfer, do not send the resource fork header, or it will be appended into the fileWrapper data
 855                 if fileTransfer.fileResumeData == nil {
 856                         err = binary.Write(rwc, binary.BigEndian, fw.rsrcForkHeader())
 857                         if err != nil {
 858                                 return err
 859                         }
 860                 }
 861
 862                 rFile, err := fw.rsrcForkFile()
 863                 if err != nil {
 864                         return nil
 865                 }
 866
 867                 if _, err = io.Copy(rwc, io.TeeReader(rFile, fileTransfer.bytesSentCounter)); err != nil {
 868                         return err
 869                 }
 870
 871         case FileUpload:
 872                 s.Stats.UploadCounter += 1
 873                 s.Stats.UploadsInProgress += 1
 874                 defer func() { s.Stats.UploadsInProgress -= 1 }()
 875
 876                 var file *os.File
 877
 878                 // A file upload has three possible cases:
 879                 // 1) Upload a new file
 880                 // 2) Resume a partially transferred file
 881                 // 3) Replace a fully uploaded file
 882                 //  We have to infer which case applies by inspecting what is already on the filesystem
 883
 884                 // 1) Check for existing file:
 885                 _, err = os.Stat(fullPath)
 886                 if err == nil {
 887                         return errors.New("existing file found at " + fullPath)
 888                 }
 889                 if errors.Is(err, fs.ErrNotExist) {
 890                         // If not found, open or create a new .incomplete file
 891                         file, err = os.OpenFile(fullPath+incompleteFileSuffix, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0644)
 892                         if err != nil {
 893                                 return err
 894                         }
 895                 }
 896
 897                 f, err := newFileWrapper(s.FS, fullPath, 0)
 898                 if err != nil {
 899                         return err
 900                 }
 901
 902                 rLogger.Infow("File upload started", "dstFile", fullPath)
 903
 904                 rForkWriter := io.Discard
 905                 iForkWriter := io.Discard
 906                 if s.Config.PreserveResourceForks {
 907                         rForkWriter, err = f.rsrcForkWriter()
 908                         if err != nil {
 909                                 return err
 910                         }
 911
 912                         iForkWriter, err = f.infoForkWriter()
 913                         if err != nil {
 914                                 return err
 915                         }
 916                 }
 917
 918                 if err := receiveFile(rwc, file, rForkWriter, iForkWriter, fileTransfer.bytesSentCounter); err != nil {
 919                         s.Logger.Error(err)
 920                 }
 921
 922                 if err := file.Close(); err != nil {
 923                         return err
 924                 }
 925
 926                 if err := s.FS.Rename(fullPath+".incomplete", fullPath); err != nil {
 927                         return err
 928                 }
 929
 930                 rLogger.Infow("File upload complete", "dstFile", fullPath)
 931
 932         case FolderDownload:
 933                 s.Stats.DownloadCounter += 1
 934                 s.Stats.DownloadsInProgress += 1
 935                 defer func() { s.Stats.DownloadsInProgress -= 1 }()
 936
 937                 // Folder Download flow:
 938                 // 1. Get filePath from the transfer
 939                 // 2. Iterate over files
 940                 // 3. For each fileWrapper:
 941                 //       Send fileWrapper header to client
 942                 // The client can reply in 3 ways:
 943                 //
 944                 // 1. If type is an odd number (unknown type?), or fileWrapper download for the current fileWrapper is completed:
 945                 //              client sends []byte{0x00, 0x03} to tell the server to continue to the next fileWrapper
 946                 //
 947                 // 2. If download of a fileWrapper is to be resumed:
 948                 //              client sends:
 949                 //                      []byte{0x00, 0x02} // download folder action
 950                 //                      [2]byte // Resume data size
 951                 //                      []byte fileWrapper resume data (see myField_FileResumeData)
 952                 //
 953                 // 3. Otherwise, download of the fileWrapper is requested and client sends []byte{0x00, 0x01}
 954                 //
 955                 // When download is requested (case 2 or 3), server replies with:
 956                 //                      [4]byte - fileWrapper size
 957                 //                      []byte  - Flattened File Object
 958                 //
 959                 // After every fileWrapper download, client could request next fileWrapper with:
 960                 //                      []byte{0x00, 0x03}
 961                 //
 962                 // This notifies the server to send the next item header
 963
 964                 basePathLen := len(fullPath)
 965
 966                 rLogger.Infow("Start folder download", "path", fullPath)
 967
 968                 nextAction := make([]byte, 2)
 969                 if _, err := io.ReadFull(rwc, nextAction); err != nil {
 970                         return err
 971                 }
 972
 973                 i := 0
 974                 err = filepath.Walk(fullPath+"/", func(path string, info os.FileInfo, err error) error {
 975                         s.Stats.DownloadCounter += 1
 976                         i += 1
 977
 978                         if err != nil {
 979                                 return err
 980                         }
 981
 982                         // skip dot files
 983                         if strings.HasPrefix(info.Name(), ".") {
 984                                 return nil
 985                         }
 986
 987                         hlFile, err := newFileWrapper(s.FS, path, 0)
 988                         if err != nil {
 989                                 return err
 990                         }
 991
 992                         subPath := path[basePathLen+1:]
 993                         rLogger.Debugw("Sending fileheader", "i", i, "path", path, "fullFilePath", fullPath, "subPath", subPath, "IsDir", info.IsDir())
 994
 995                         if i == 1 {
 996                                 return nil
 997                         }
 998
 999                         fileHeader := NewFileHeader(subPath, info.IsDir())
1000
1001                         // Send the fileWrapper header to client
1002                         if _, err := rwc.Write(fileHeader.Payload()); err != nil {
1003                                 s.Logger.Errorf("error sending file header: %v", err)
1004                                 return err
1005                         }
1006
1007                         // Read the client's Next Action request
1008                         if _, err := io.ReadFull(rwc, nextAction); err != nil {
1009                                 return err
1010                         }
1011
1012                         rLogger.Debugw("Client folder download action", "action", fmt.Sprintf("%X", nextAction[0:2]))
1013
1014                         var dataOffset int64
1015
1016                         switch nextAction[1] {
1017                         case dlFldrActionResumeFile:
1018                                 // get size of resumeData
1019                                 resumeDataByteLen := make([]byte, 2)
1020                                 if _, err := io.ReadFull(rwc, resumeDataByteLen); err != nil {
1021                                         return err
1022                                 }
1023
1024                                 resumeDataLen := binary.BigEndian.Uint16(resumeDataByteLen)
1025                                 resumeDataBytes := make([]byte, resumeDataLen)
1026                                 if _, err := io.ReadFull(rwc, resumeDataBytes); err != nil {
1027                                         return err
1028                                 }
1029
1030                                 var frd FileResumeData
1031                                 if err := frd.UnmarshalBinary(resumeDataBytes); err != nil {
1032                                         return err
1033                                 }
1034                                 dataOffset = int64(binary.BigEndian.Uint32(frd.ForkInfoList[0].DataSize[:]))
1035                         case dlFldrActionNextFile:
1036                                 // client asked to skip this file
1037                                 return nil
1038                         }
1039
1040                         if info.IsDir() {
1041                                 return nil
1042                         }
1043
1044                         rLogger.Infow("File download started",
1045                                 "fileName", info.Name(),
1046                                 "TransferSize", fmt.Sprintf("%x", hlFile.ffo.TransferSize(dataOffset)),
1047                         )
1048
1049                         // Send file size to client
1050                         if _, err := rwc.Write(hlFile.ffo.TransferSize(dataOffset)); err != nil {
1051                                 s.Logger.Error(err)
1052                                 return err
1053                         }
1054
1055                         // Send ffo bytes to client
1056                         if _, err := rwc.Write(hlFile.ffo.BinaryMarshal()); err != nil {
1057                                 s.Logger.Error(err)
1058                                 return err
1059                         }
1060
1061                         file, err := s.FS.Open(path)
1062                         if err != nil {
1063                                 return err
1064                         }
1065
1066                         // wr := bufio.NewWriterSize(rwc, 1460)
1067                         if _, err = io.Copy(rwc, io.TeeReader(file, fileTransfer.bytesSentCounter)); err != nil {
1068                                 return err
1069                         }
1070
1071                         if nextAction[1] != 2 && hlFile.ffo.FlatFileHeader.ForkCount[1] == 3 {
1072                                 err = binary.Write(rwc, binary.BigEndian, hlFile.rsrcForkHeader())
1073                                 if err != nil {
1074                                         return err
1075                                 }
1076
1077                                 rFile, err := hlFile.rsrcForkFile()
1078                                 if err != nil {
1079                                         return err
1080                                 }
1081
1082                                 if _, err = io.Copy(rwc, io.TeeReader(rFile, fileTransfer.bytesSentCounter)); err != nil {
1083                                         return err
1084                                 }
1085                         }
1086
1087                         // Read the client's Next Action request.  This is always 3, I think?
1088                         if _, err := io.ReadFull(rwc, nextAction); err != nil {
1089                                 return err
1090                         }
1091
1092                         return nil
1093                 })
1094
1095                 if err != nil {
1096                         return err
1097                 }
1098
1099         case FolderUpload:
1100                 s.Stats.UploadCounter += 1
1101                 s.Stats.UploadsInProgress += 1
1102                 defer func() { s.Stats.UploadsInProgress -= 1 }()
1103                 rLogger.Infow(
1104                         "Folder upload started",
1105                         "dstPath", fullPath,
1106                         "TransferSize", binary.BigEndian.Uint32(fileTransfer.TransferSize),
1107                         "FolderItemCount", fileTransfer.FolderItemCount,
1108                 )
1109
1110                 // Check if the target folder exists.  If not, create it.
1111                 if _, err := s.FS.Stat(fullPath); os.IsNotExist(err) {
1112                         if err := s.FS.Mkdir(fullPath, 0777); err != nil {
1113                                 return err
1114                         }
1115                 }
1116
1117                 // Begin the folder upload flow by sending the "next file action" to client
1118                 if _, err := rwc.Write([]byte{0, dlFldrActionNextFile}); err != nil {
1119                         return err
1120                 }
1121
1122                 fileSize := make([]byte, 4)
1123
1124                 for i := 0; i < fileTransfer.ItemCount(); i++ {
1125                         s.Stats.UploadCounter += 1
1126
1127                         var fu folderUpload
1128                         if _, err := io.ReadFull(rwc, fu.DataSize[:]); err != nil {
1129                                 return err
1130                         }
1131                         if _, err := io.ReadFull(rwc, fu.IsFolder[:]); err != nil {
1132                                 return err
1133                         }
1134                         if _, err := io.ReadFull(rwc, fu.PathItemCount[:]); err != nil {
1135                                 return err
1136                         }
1137
1138                         fu.FileNamePath = make([]byte, binary.BigEndian.Uint16(fu.DataSize[:])-4) // -4 to subtract the path separator bytes
1139
1140                         if _, err := io.ReadFull(rwc, fu.FileNamePath); err != nil {
1141                                 return err
1142                         }
1143
1144                         rLogger.Infow(
1145                                 "Folder upload continued",
1146                                 "FormattedPath", fu.FormattedPath(),
1147                                 "IsFolder", fmt.Sprintf("%x", fu.IsFolder),
1148                                 "PathItemCount", binary.BigEndian.Uint16(fu.PathItemCount[:]),
1149                         )
1150
1151                         if fu.IsFolder == [2]byte{0, 1} {
1152                                 if _, err := os.Stat(filepath.Join(fullPath, fu.FormattedPath())); os.IsNotExist(err) {
1153                                         if err := os.Mkdir(filepath.Join(fullPath, fu.FormattedPath()), 0777); err != nil {
1154                                                 return err
1155                                         }
1156                                 }
1157
1158                                 // Tell client to send next file
1159                                 if _, err := rwc.Write([]byte{0, dlFldrActionNextFile}); err != nil {
1160                                         return err
1161                                 }
1162                         } else {
1163                                 nextAction := dlFldrActionSendFile
1164
1165                                 // Check if we have the full file already.  If so, send dlFldrAction_NextFile to client to skip.
1166                                 _, err = os.Stat(filepath.Join(fullPath, fu.FormattedPath()))
1167                                 if err != nil && !errors.Is(err, fs.ErrNotExist) {
1168                                         return err
1169                                 }
1170                                 if err == nil {
1171                                         nextAction = dlFldrActionNextFile
1172                                 }
1173
1174                                 //  Check if we have a partial file already.  If so, send dlFldrAction_ResumeFile to client to resume upload.
1175                                 incompleteFile, err := os.Stat(filepath.Join(fullPath, fu.FormattedPath()+incompleteFileSuffix))
1176                                 if err != nil && !errors.Is(err, fs.ErrNotExist) {
1177                                         return err
1178                                 }
1179                                 if err == nil {
1180                                         nextAction = dlFldrActionResumeFile
1181                                 }
1182
1183                                 if _, err := rwc.Write([]byte{0, uint8(nextAction)}); err != nil {
1184                                         return err
1185                                 }
1186
1187                                 switch nextAction {
1188                                 case dlFldrActionNextFile:
1189                                         continue
1190                                 case dlFldrActionResumeFile:
1191                                         offset := make([]byte, 4)
1192                                         binary.BigEndian.PutUint32(offset, uint32(incompleteFile.Size()))
1193
1194                                         file, err := os.OpenFile(fullPath+"/"+fu.FormattedPath()+incompleteFileSuffix, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
1195                                         if err != nil {
1196                                                 return err
1197                                         }
1198
1199                                         fileResumeData := NewFileResumeData([]ForkInfoList{*NewForkInfoList(offset)})
1200
1201                                         b, _ := fileResumeData.BinaryMarshal()
1202
1203                                         bs := make([]byte, 2)
1204                                         binary.BigEndian.PutUint16(bs, uint16(len(b)))
1205
1206                                         if _, err := rwc.Write(append(bs, b...)); err != nil {
1207                                                 return err
1208                                         }
1209
1210                                         if _, err := io.ReadFull(rwc, fileSize); err != nil {
1211                                                 return err
1212                                         }
1213
1214                                         if err := receiveFile(rwc, file, io.Discard, io.Discard, fileTransfer.bytesSentCounter); err != nil {
1215                                                 s.Logger.Error(err)
1216                                         }
1217
1218                                         err = os.Rename(fullPath+"/"+fu.FormattedPath()+".incomplete", fullPath+"/"+fu.FormattedPath())
1219                                         if err != nil {
1220                                                 return err
1221                                         }
1222
1223                                 case dlFldrActionSendFile:
1224                                         if _, err := io.ReadFull(rwc, fileSize); err != nil {
1225                                                 return err
1226                                         }
1227
1228                                         filePath := filepath.Join(fullPath, fu.FormattedPath())
1229
1230                                         hlFile, err := newFileWrapper(s.FS, filePath, 0)
1231                                         if err != nil {
1232                                                 return err
1233                                         }
1234
1235                                         rLogger.Infow("Starting file transfer", "path", filePath, "fileNum", i+1, "fileSize", binary.BigEndian.Uint32(fileSize))
1236
1237                                         incWriter, err := hlFile.incFileWriter()
1238                                         if err != nil {
1239                                                 return err
1240                                         }
1241
1242                                         rForkWriter := io.Discard
1243                                         iForkWriter := io.Discard
1244                                         if s.Config.PreserveResourceForks {
1245                                                 iForkWriter, err = hlFile.infoForkWriter()
1246                                                 if err != nil {
1247                                                         return err
1248                                                 }
1249
1250                                                 rForkWriter, err = hlFile.rsrcForkWriter()
1251                                                 if err != nil {
1252                                                         return err
1253                                                 }
1254                                         }
1255                                         if err := receiveFile(rwc, incWriter, rForkWriter, iForkWriter, fileTransfer.bytesSentCounter); err != nil {
1256                                                 return err
1257                                         }
1258
1259                                         if err := os.Rename(filePath+".incomplete", filePath); err != nil {
1260                                                 return err
1261                                         }
1262                                 }
1263
1264                                 // Tell client to send next fileWrapper
1265                                 if _, err := rwc.Write([]byte{0, dlFldrActionNextFile}); err != nil {
1266                                         return err
1267                                 }
1268                         }
1269                 }
1270                 rLogger.Infof("Folder upload complete")
1271         }
1272
1273         return nil
1274 }