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         "golang.org/x/text/encoding/charmap"
  12         "gopkg.in/yaml.v3"
  13         "io"
  14         "io/fs"
  15         "math/big"
  16         "math/rand"
  17         "net"
  18         "os"
  19         "path"
  20         "path/filepath"
  21         "strings"
  22         "sync"
  23         "time"
  24 )
  25
  26 type contextKey string
  27
  28 var contextKeyReq = contextKey("req")
  29
  30 type requestCtx struct {
  31         remoteAddr string
  32 }
  33
  34 // Converts bytes from Mac Roman encoding to UTF-8
  35 var txtDecoder = charmap.Macintosh.NewDecoder()
  36
  37 // Converts bytes from UTF-8 to Mac Roman encoding
  38 var txtEncoder = charmap.Macintosh.NewEncoder()
  39
  40 type Server struct {
  41         NetInterface  string
  42         Port          int
  43         Accounts      map[string]*Account
  44         Agreement     []byte
  45         Clients       map[uint16]*ClientConn
  46         fileTransfers map[[4]byte]*FileTransfer
  47
  48         Config    *Config
  49         ConfigDir string
  50         Logger    *zap.SugaredLogger
  51
  52         PrivateChatsMu sync.Mutex
  53         PrivateChats   map[uint32]*PrivateChat
  54
  55         NextGuestID   *uint16
  56         TrackerPassID [4]byte
  57
  58         StatsMu sync.Mutex
  59         Stats   *Stats
  60
  61         FS FileStore // Storage backend to use for File storage
  62
  63         outbox chan Transaction
  64         mux    sync.Mutex
  65
  66         threadedNewsMux sync.Mutex
  67         ThreadedNews    *ThreadedNews
  68
  69         flatNewsMux sync.Mutex
  70         FlatNews    []byte
  71
  72         banListMU sync.Mutex
  73         banList   map[string]*time.Time
  74 }
  75
  76 func (s *Server) CurrentStats() Stats {
  77         s.StatsMu.Lock()
  78         defer s.StatsMu.Unlock()
  79
  80         stats := s.Stats
  81         stats.CurrentlyConnected = len(s.Clients)
  82
  83         return *stats
  84 }
  85
  86 type PrivateChat struct {
  87         Subject    string
  88         ClientConn map[uint16]*ClientConn
  89 }
  90
  91 func (s *Server) ListenAndServe(ctx context.Context, cancelRoot context.CancelFunc) error {
  92         s.Logger.Infow("Hotline server started",
  93                 "version", VERSION,
  94                 "API port", fmt.Sprintf("%s:%v", s.NetInterface, s.Port),
  95                 "Transfer port", fmt.Sprintf("%s:%v", s.NetInterface, s.Port+1),
  96         )
  97
  98         var wg sync.WaitGroup
  99
 100         wg.Add(1)
 101         go func() {
 102                 ln, err := net.Listen("tcp", fmt.Sprintf("%s:%v", s.NetInterface, s.Port))
 103                 if err != nil {
 104                         s.Logger.Fatal(err)
 105                 }
 106
 107                 s.Logger.Fatal(s.Serve(ctx, ln))
 108         }()
 109
 110         wg.Add(1)
 111         go func() {
 112                 ln, err := net.Listen("tcp", fmt.Sprintf("%s:%v", s.NetInterface, s.Port+1))
 113                 if err != nil {
 114                         s.Logger.Fatal(err)
 115                 }
 116
 117                 s.Logger.Fatal(s.ServeFileTransfers(ctx, ln))
 118         }()
 119
 120         wg.Wait()
 121
 122         return nil
 123 }
 124
 125 func (s *Server) ServeFileTransfers(ctx context.Context, ln net.Listener) error {
 126         for {
 127                 conn, err := ln.Accept()
 128                 if err != nil {
 129                         return err
 130                 }
 131
 132                 go func() {
 133                         defer func() { _ = conn.Close() }()
 134
 135                         err = s.handleFileTransfer(
 136                                 context.WithValue(ctx, contextKeyReq, requestCtx{
 137                                         remoteAddr: conn.RemoteAddr().String(),
 138                                 }),
 139                                 conn,
 140                         )
 141
 142                         if err != nil {
 143                                 s.Logger.Errorw("file transfer error", "reason", err)
 144                         }
 145                 }()
 146         }
 147 }
 148
 149 func (s *Server) sendTransaction(t Transaction) error {
 150         clientID, err := byteToInt(*t.clientID)
 151         if err != nil {
 152                 return err
 153         }
 154
 155         s.mux.Lock()
 156         client := s.Clients[uint16(clientID)]
 157         s.mux.Unlock()
 158         if client == nil {
 159                 return fmt.Errorf("invalid client id %v", *t.clientID)
 160         }
 161
 162         b, err := t.MarshalBinary()
 163         if err != nil {
 164                 return err
 165         }
 166
 167         _, err = client.Connection.Write(b)
 168         if err != nil {
 169                 return err
 170         }
 171
 172         return nil
 173 }
 174
 175 func (s *Server) processOutbox() {
 176         for {
 177                 t := <-s.outbox
 178                 go func() {
 179                         if err := s.sendTransaction(t); err != nil {
 180                                 s.Logger.Errorw("error sending transaction", "err", err)
 181                         }
 182                 }()
 183         }
 184 }
 185
 186 func (s *Server) Serve(ctx context.Context, ln net.Listener) error {
 187         go s.processOutbox()
 188
 189         for {
 190                 conn, err := ln.Accept()
 191                 if err != nil {
 192                         s.Logger.Errorw("error accepting connection", "err", err)
 193                 }
 194                 connCtx := context.WithValue(ctx, contextKeyReq, requestCtx{
 195                         remoteAddr: conn.RemoteAddr().String(),
 196                 })
 197
 198                 go func() {
 199                         s.Logger.Infow("Connection established", "RemoteAddr", conn.RemoteAddr())
 200
 201                         defer conn.Close()
 202                         if err := s.handleNewConnection(connCtx, conn, conn.RemoteAddr().String()); err != nil {
 203                                 if err == io.EOF {
 204                                         s.Logger.Infow("Client disconnected", "RemoteAddr", conn.RemoteAddr())
 205                                 } else {
 206                                         s.Logger.Errorw("error serving request", "RemoteAddr", conn.RemoteAddr(), "err", err)
 207                                 }
 208                         }
 209                 }()
 210         }
 211 }
 212
 213 const (
 214         agreementFile = "Agreement.txt"
 215 )
 216
 217 // NewServer constructs a new Server from a config dir
 218 func NewServer(configDir, netInterface string, netPort int, logger *zap.SugaredLogger, fs FileStore) (*Server, error) {
 219         server := Server{
 220                 NetInterface:  netInterface,
 221                 Port:          netPort,
 222                 Accounts:      make(map[string]*Account),
 223                 Config:        new(Config),
 224                 Clients:       make(map[uint16]*ClientConn),
 225                 fileTransfers: make(map[[4]byte]*FileTransfer),
 226                 PrivateChats:  make(map[uint32]*PrivateChat),
 227                 ConfigDir:     configDir,
 228                 Logger:        logger,
 229                 NextGuestID:   new(uint16),
 230                 outbox:        make(chan Transaction),
 231                 Stats:         &Stats{Since: time.Now()},
 232                 ThreadedNews:  &ThreadedNews{},
 233                 FS:            fs,
 234                 banList:       make(map[string]*time.Time),
 235         }
 236
 237         var err error
 238
 239         // generate a new random passID for tracker registration
 240         if _, err := rand.Read(server.TrackerPassID[:]); err != nil {
 241                 return nil, err
 242         }
 243
 244         server.Agreement, err = os.ReadFile(filepath.Join(configDir, agreementFile))
 245         if err != nil {
 246                 return nil, err
 247         }
 248
 249         if server.FlatNews, err = os.ReadFile(filepath.Join(configDir, "MessageBoard.txt")); err != nil {
 250                 return nil, err
 251         }
 252
 253         // try to load the ban list, but ignore errors as this file may not be present or may be empty
 254         _ = server.loadBanList(filepath.Join(configDir, "Banlist.yaml"))
 255
 256         if err := server.loadThreadedNews(filepath.Join(configDir, "ThreadedNews.yaml")); err != nil {
 257                 return nil, err
 258         }
 259
 260         if err := server.loadConfig(filepath.Join(configDir, "config.yaml")); err != nil {
 261                 return nil, err
 262         }
 263
 264         if err := server.loadAccounts(filepath.Join(configDir, "Users/")); err != nil {
 265                 return nil, err
 266         }
 267
 268         // If the FileRoot is an absolute path, use it, otherwise treat as a relative path to the config dir.
 269         if !filepath.IsAbs(server.Config.FileRoot) {
 270                 server.Config.FileRoot = filepath.Join(configDir, server.Config.FileRoot)
 271         }
 272
 273         *server.NextGuestID = 1
 274
 275         if server.Config.EnableTrackerRegistration {
 276                 server.Logger.Infow(
 277                         "Tracker registration enabled",
 278                         "frequency", fmt.Sprintf("%vs", trackerUpdateFrequency),
 279                         "trackers", server.Config.Trackers,
 280                 )
 281
 282                 go func() {
 283                         for {
 284                                 tr := &TrackerRegistration{
 285                                         UserCount:   server.userCount(),
 286                                         PassID:      server.TrackerPassID,
 287                                         Name:        server.Config.Name,
 288                                         Description: server.Config.Description,
 289                                 }
 290                                 binary.BigEndian.PutUint16(tr.Port[:], uint16(server.Port))
 291                                 for _, t := range server.Config.Trackers {
 292                                         if err := register(t, tr); err != nil {
 293                                                 server.Logger.Errorw("unable to register with tracker %v", "error", err)
 294                                         }
 295                                         server.Logger.Debugw("Sent Tracker registration", "addr", t)
 296                                 }
 297
 298                                 time.Sleep(trackerUpdateFrequency * time.Second)
 299                         }
 300                 }()
 301         }
 302
 303         // Start Client Keepalive go routine
 304         go server.keepaliveHandler()
 305
 306         return &server, nil
 307 }
 308
 309 func (s *Server) userCount() int {
 310         s.mux.Lock()
 311         defer s.mux.Unlock()
 312
 313         return len(s.Clients)
 314 }
 315
 316 func (s *Server) keepaliveHandler() {
 317         for {
 318                 time.Sleep(idleCheckInterval * time.Second)
 319                 s.mux.Lock()
 320
 321                 for _, c := range s.Clients {
 322                         c.IdleTime += idleCheckInterval
 323                         if c.IdleTime > userIdleSeconds && !c.Idle {
 324                                 c.Idle = true
 325
 326                                 flagBitmap := big.NewInt(int64(binary.BigEndian.Uint16(c.Flags)))
 327                                 flagBitmap.SetBit(flagBitmap, UserFlagAway, 1)
 328                                 binary.BigEndian.PutUint16(c.Flags, uint16(flagBitmap.Int64()))
 329
 330                                 c.sendAll(
 331                                         TranNotifyChangeUser,
 332                                         NewField(FieldUserID, *c.ID),
 333                                         NewField(FieldUserFlags, c.Flags),
 334                                         NewField(FieldUserName, c.UserName),
 335                                         NewField(FieldUserIconID, c.Icon),
 336                                 )
 337                         }
 338                 }
 339                 s.mux.Unlock()
 340         }
 341 }
 342
 343 func (s *Server) writeBanList() error {
 344         s.banListMU.Lock()
 345         defer s.banListMU.Unlock()
 346
 347         out, err := yaml.Marshal(s.banList)
 348         if err != nil {
 349                 return err
 350         }
 351         err = os.WriteFile(
 352                 filepath.Join(s.ConfigDir, "Banlist.yaml"),
 353                 out,
 354                 0666,
 355         )
 356         return err
 357 }
 358
 359 func (s *Server) writeThreadedNews() error {
 360         s.threadedNewsMux.Lock()
 361         defer s.threadedNewsMux.Unlock()
 362
 363         out, err := yaml.Marshal(s.ThreadedNews)
 364         if err != nil {
 365                 return err
 366         }
 367         err = s.FS.WriteFile(
 368                 filepath.Join(s.ConfigDir, "ThreadedNews.yaml"),
 369                 out,
 370                 0666,
 371         )
 372         return err
 373 }
 374
 375 func (s *Server) NewClientConn(conn io.ReadWriteCloser, remoteAddr string) *ClientConn {
 376         s.mux.Lock()
 377         defer s.mux.Unlock()
 378
 379         clientConn := &ClientConn{
 380                 ID:         &[]byte{0, 0},
 381                 Icon:       []byte{0, 0},
 382                 Flags:      []byte{0, 0},
 383                 UserName:   []byte{},
 384                 Connection: conn,
 385                 Server:     s,
 386                 Version:    []byte{},
 387                 AutoReply:  []byte{},
 388                 RemoteAddr: remoteAddr,
 389                 transfers: map[int]map[[4]byte]*FileTransfer{
 390                         FileDownload:   {},
 391                         FileUpload:     {},
 392                         FolderDownload: {},
 393                         FolderUpload:   {},
 394                         bannerDownload: {},
 395                 },
 396         }
 397
 398         *s.NextGuestID++
 399         ID := *s.NextGuestID
 400
 401         binary.BigEndian.PutUint16(*clientConn.ID, ID)
 402         s.Clients[ID] = clientConn
 403
 404         return clientConn
 405 }
 406
 407 // NewUser creates a new user account entry in the server map and config file
 408 func (s *Server) NewUser(login, name, password string, access accessBitmap) error {
 409         s.mux.Lock()
 410         defer s.mux.Unlock()
 411
 412         account := Account{
 413                 Login:    login,
 414                 Name:     name,
 415                 Password: hashAndSalt([]byte(password)),
 416                 Access:   access,
 417         }
 418         out, err := yaml.Marshal(&account)
 419         if err != nil {
 420                 return err
 421         }
 422
 423         // Create account file, returning an error if one already exists.
 424         file, err := os.OpenFile(
 425                 filepath.Join(s.ConfigDir, "Users", path.Join("/", login)+".yaml"),
 426                 os.O_CREATE|os.O_EXCL|os.O_WRONLY,
 427                 0644,
 428         )
 429         if err != nil {
 430                 return err
 431         }
 432         defer file.Close()
 433
 434         _, err = file.Write(out)
 435         if err != nil {
 436                 return fmt.Errorf("error writing account file: %w", err)
 437         }
 438
 439         s.Accounts[login] = &account
 440
 441         return nil
 442 }
 443
 444 func (s *Server) UpdateUser(login, newLogin, name, password string, access accessBitmap) error {
 445         s.mux.Lock()
 446         defer s.mux.Unlock()
 447
 448         // update renames the user login
 449         if login != newLogin {
 450                 err := os.Rename(filepath.Join(s.ConfigDir, "Users", path.Join("/", login)+".yaml"), filepath.Join(s.ConfigDir, "Users", path.Join("/", newLogin)+".yaml"))
 451                 if err != nil {
 452                         return fmt.Errorf("unable to rename account: %w", err)
 453                 }
 454                 s.Accounts[newLogin] = s.Accounts[login]
 455                 s.Accounts[newLogin].Login = newLogin
 456                 delete(s.Accounts, login)
 457         }
 458
 459         account := s.Accounts[newLogin]
 460         account.Access = access
 461         account.Name = name
 462         account.Password = password
 463
 464         out, err := yaml.Marshal(&account)
 465         if err != nil {
 466                 return err
 467         }
 468
 469         if err := os.WriteFile(filepath.Join(s.ConfigDir, "Users", newLogin+".yaml"), out, 0666); err != nil {
 470                 return err
 471         }
 472
 473         return nil
 474 }
 475
 476 // DeleteUser deletes the user account
 477 func (s *Server) DeleteUser(login string) error {
 478         s.mux.Lock()
 479         defer s.mux.Unlock()
 480
 481         err := s.FS.Remove(filepath.Join(s.ConfigDir, "Users", path.Join("/", login)+".yaml"))
 482         if err != nil {
 483                 return err
 484         }
 485
 486         delete(s.Accounts, login)
 487
 488         return nil
 489 }
 490
 491 func (s *Server) connectedUsers() []Field {
 492         s.mux.Lock()
 493         defer s.mux.Unlock()
 494
 495         var connectedUsers []Field
 496         for _, c := range sortedClients(s.Clients) {
 497                 b, err := io.ReadAll(&User{
 498                         ID:    *c.ID,
 499                         Icon:  c.Icon,
 500                         Flags: c.Flags,
 501                         Name:  string(c.UserName),
 502                 })
 503                 if err != nil {
 504                         return nil
 505                 }
 506                 connectedUsers = append(connectedUsers, NewField(FieldUsernameWithInfo, b))
 507         }
 508         return connectedUsers
 509 }
 510
 511 func (s *Server) loadBanList(path string) error {
 512         fh, err := os.Open(path)
 513         if err != nil {
 514                 return err
 515         }
 516         decoder := yaml.NewDecoder(fh)
 517
 518         return decoder.Decode(s.banList)
 519 }
 520
 521 // loadThreadedNews loads the threaded news data from disk
 522 func (s *Server) loadThreadedNews(threadedNewsPath string) error {
 523         fh, err := os.Open(threadedNewsPath)
 524         if err != nil {
 525                 return err
 526         }
 527         decoder := yaml.NewDecoder(fh)
 528
 529         return decoder.Decode(s.ThreadedNews)
 530 }
 531
 532 // loadAccounts loads account data from disk
 533 func (s *Server) loadAccounts(userDir string) error {
 534         matches, err := filepath.Glob(filepath.Join(userDir, "*.yaml"))
 535         if err != nil {
 536                 return err
 537         }
 538
 539         if len(matches) == 0 {
 540                 return errors.New("no user accounts found in " + userDir)
 541         }
 542
 543         for _, file := range matches {
 544                 fh, err := s.FS.Open(file)
 545                 if err != nil {
 546                         return err
 547                 }
 548
 549                 account := Account{}
 550                 decoder := yaml.NewDecoder(fh)
 551                 if err = decoder.Decode(&account); err != nil {
 552                         return fmt.Errorf("error loading account %s: %w", file, err)
 553                 }
 554
 555                 s.Accounts[account.Login] = &account
 556         }
 557         return nil
 558 }
 559
 560 func (s *Server) loadConfig(path string) error {
 561         fh, err := s.FS.Open(path)
 562         if err != nil {
 563                 return err
 564         }
 565
 566         decoder := yaml.NewDecoder(fh)
 567         err = decoder.Decode(s.Config)
 568         if err != nil {
 569                 return err
 570         }
 571
 572         validate := validator.New()
 573         err = validate.Struct(s.Config)
 574         if err != nil {
 575                 return err
 576         }
 577         return nil
 578 }
 579
 580 // handleNewConnection takes a new net.Conn and performs the initial login sequence
 581 func (s *Server) handleNewConnection(ctx context.Context, rwc io.ReadWriteCloser, remoteAddr string) error {
 582         defer dontPanic(s.Logger)
 583
 584         if err := Handshake(rwc); err != nil {
 585                 return err
 586         }
 587
 588         // Create a new scanner for parsing incoming bytes into transaction tokens
 589         scanner := bufio.NewScanner(rwc)
 590         scanner.Split(transactionScanner)
 591
 592         scanner.Scan()
 593
 594         // Make a new []byte slice and copy the scanner bytes to it.  This is critical to avoid a data race as the
 595         // scanner re-uses the buffer for subsequent scans.
 596         buf := make([]byte, len(scanner.Bytes()))
 597         copy(buf, scanner.Bytes())
 598
 599         var clientLogin Transaction
 600         if _, err := clientLogin.Write(buf); err != nil {
 601                 return err
 602         }
 603
 604         // check if remoteAddr is present in the ban list
 605         if banUntil, ok := s.banList[strings.Split(remoteAddr, ":")[0]]; ok {
 606                 // permaban
 607                 if banUntil == nil {
 608                         t := NewTransaction(
 609                                 TranServerMsg,
 610                                 &[]byte{0, 0},
 611                                 NewField(FieldData, []byte("You are permanently banned on this server")),
 612                                 NewField(FieldChatOptions, []byte{0, 0}),
 613                         )
 614
 615                         b, err := t.MarshalBinary()
 616                         if err != nil {
 617                                 return err
 618                         }
 619
 620                         _, err = rwc.Write(b)
 621                         if err != nil {
 622                                 return err
 623                         }
 624
 625                         time.Sleep(1 * time.Second)
 626                         return nil
 627                 }
 628
 629                 // temporary ban
 630                 if time.Now().Before(*banUntil) {
 631                         t := NewTransaction(
 632                                 TranServerMsg,
 633                                 &[]byte{0, 0},
 634                                 NewField(FieldData, []byte("You are temporarily banned on this server")),
 635                                 NewField(FieldChatOptions, []byte{0, 0}),
 636                         )
 637                         b, err := t.MarshalBinary()
 638                         if err != nil {
 639                                 return err
 640                         }
 641
 642                         _, err = rwc.Write(b)
 643                         if err != nil {
 644                                 return err
 645                         }
 646
 647                         time.Sleep(1 * time.Second)
 648                         return nil
 649                 }
 650         }
 651
 652         c := s.NewClientConn(rwc, remoteAddr)
 653         defer c.Disconnect()
 654
 655         encodedLogin := clientLogin.GetField(FieldUserLogin).Data
 656         encodedPassword := clientLogin.GetField(FieldUserPassword).Data
 657         c.Version = clientLogin.GetField(FieldVersion).Data
 658
 659         var login string
 660         for _, char := range encodedLogin {
 661                 login += string(rune(255 - uint(char)))
 662         }
 663         if login == "" {
 664                 login = GuestAccount
 665         }
 666
 667         c.logger = s.Logger.With("remoteAddr", remoteAddr, "login", login)
 668
 669         // If authentication fails, send error reply and close connection
 670         if !c.Authenticate(login, encodedPassword) {
 671                 t := c.NewErrReply(&clientLogin, "Incorrect login.")
 672                 b, err := t.MarshalBinary()
 673                 if err != nil {
 674                         return err
 675                 }
 676                 if _, err := rwc.Write(b); err != nil {
 677                         return err
 678                 }
 679
 680                 c.logger.Infow("Login failed", "clientVersion", fmt.Sprintf("%x", c.Version))
 681
 682                 return nil
 683         }
 684
 685         if clientLogin.GetField(FieldUserIconID).Data != nil {
 686                 c.Icon = clientLogin.GetField(FieldUserIconID).Data
 687         }
 688
 689         c.Account = c.Server.Accounts[login]
 690
 691         if clientLogin.GetField(FieldUserName).Data != nil {
 692                 if c.Authorize(accessAnyName) {
 693                         c.UserName = clientLogin.GetField(FieldUserName).Data
 694                 } else {
 695                         c.UserName = []byte(c.Account.Name)
 696                 }
 697         }
 698
 699         if c.Authorize(accessDisconUser) {
 700                 c.Flags = []byte{0, 2}
 701         }
 702
 703         s.outbox <- c.NewReply(&clientLogin,
 704                 NewField(FieldVersion, []byte{0x00, 0xbe}),
 705                 NewField(FieldCommunityBannerID, []byte{0, 0}),
 706                 NewField(FieldServerName, []byte(s.Config.Name)),
 707         )
 708
 709         // Send user access privs so client UI knows how to behave
 710         c.Server.outbox <- *NewTransaction(TranUserAccess, c.ID, NewField(FieldUserAccess, c.Account.Access[:]))
 711
 712         // Accounts with accessNoAgreement do not receive the server agreement on login.  The behavior is different between
 713         // client versions.  For 1.2.3 client, we do not send TranShowAgreement.  For other client versions, we send
 714         // TranShowAgreement but with the NoServerAgreement field set to 1.
 715         if c.Authorize(accessNoAgreement) {
 716                 // If client version is nil, then the client uses the 1.2.3 login behavior
 717                 if c.Version != nil {
 718                         c.Server.outbox <- *NewTransaction(TranShowAgreement, c.ID, NewField(FieldNoServerAgreement, []byte{1}))
 719                 }
 720         } else {
 721                 c.Server.outbox <- *NewTransaction(TranShowAgreement, c.ID, NewField(FieldData, s.Agreement))
 722         }
 723
 724         // If the client has provided a username as part of the login, we can infer that it is using the 1.2.3 login
 725         // flow and not the 1.5+ flow.
 726         if len(c.UserName) != 0 {
 727                 // Add the client username to the logger.  For 1.5+ clients, we don't have this information yet as it comes as
 728                 // part of TranAgreed
 729                 c.logger = c.logger.With("name", string(c.UserName))
 730
 731                 c.logger.Infow("Login successful", "clientVersion", "Not sent (probably 1.2.3)")
 732
 733                 // Notify other clients on the server that the new user has logged in.  For 1.5+ clients we don't have this
 734                 // information yet, so we do it in TranAgreed instead
 735                 for _, t := range c.notifyOthers(
 736                         *NewTransaction(
 737                                 TranNotifyChangeUser, nil,
 738                                 NewField(FieldUserName, c.UserName),
 739                                 NewField(FieldUserID, *c.ID),
 740                                 NewField(FieldUserIconID, c.Icon),
 741                                 NewField(FieldUserFlags, c.Flags),
 742                         ),
 743                 ) {
 744                         c.Server.outbox <- t
 745                 }
 746         }
 747
 748         c.Server.Stats.ConnectionCounter += 1
 749         if len(s.Clients) > c.Server.Stats.ConnectionPeak {
 750                 c.Server.Stats.ConnectionPeak = len(s.Clients)
 751         }
 752
 753         // Scan for new transactions and handle them as they come in.
 754         for scanner.Scan() {
 755                 // Make a new []byte slice and copy the scanner bytes to it.  This is critical to avoid a data race as the
 756                 // scanner re-uses the buffer for subsequent scans.
 757                 buf := make([]byte, len(scanner.Bytes()))
 758                 copy(buf, scanner.Bytes())
 759
 760                 var t Transaction
 761                 if _, err := t.Write(buf); err != nil {
 762                         return err
 763                 }
 764
 765                 if err := c.handleTransaction(t); err != nil {
 766                         c.logger.Errorw("Error handling transaction", "err", err)
 767                 }
 768         }
 769         return nil
 770 }
 771
 772 func (s *Server) NewPrivateChat(cc *ClientConn) []byte {
 773         s.PrivateChatsMu.Lock()
 774         defer s.PrivateChatsMu.Unlock()
 775
 776         randID := make([]byte, 4)
 777         rand.Read(randID)
 778         data := binary.BigEndian.Uint32(randID)
 779
 780         s.PrivateChats[data] = &PrivateChat{
 781                 ClientConn: make(map[uint16]*ClientConn),
 782         }
 783         s.PrivateChats[data].ClientConn[cc.uint16ID()] = cc
 784
 785         return randID
 786 }
 787
 788 const dlFldrActionSendFile = 1
 789 const dlFldrActionResumeFile = 2
 790 const dlFldrActionNextFile = 3
 791
 792 // handleFileTransfer receives a client net.Conn from the file transfer server, performs the requested transfer type, then closes the connection
 793 func (s *Server) handleFileTransfer(ctx context.Context, rwc io.ReadWriter) error {
 794         defer dontPanic(s.Logger)
 795
 796         txBuf := make([]byte, 16)
 797         if _, err := io.ReadFull(rwc, txBuf); err != nil {
 798                 return err
 799         }
 800
 801         var t transfer
 802         if _, err := t.Write(txBuf); err != nil {
 803                 return err
 804         }
 805
 806         defer func() {
 807                 s.mux.Lock()
 808                 delete(s.fileTransfers, t.ReferenceNumber)
 809                 s.mux.Unlock()
 810
 811                 // Wait a few seconds before closing the connection: this is a workaround for problems
 812                 // observed with Windows clients where the client must initiate close of the TCP connection before
 813                 // the server does.  This is gross and seems unnecessary.  TODO: Revisit?
 814                 time.Sleep(3 * time.Second)
 815         }()
 816
 817         s.mux.Lock()
 818         fileTransfer, ok := s.fileTransfers[t.ReferenceNumber]
 819         s.mux.Unlock()
 820         if !ok {
 821                 return errors.New("invalid transaction ID")
 822         }
 823
 824         defer func() {
 825                 fileTransfer.ClientConn.transfersMU.Lock()
 826                 delete(fileTransfer.ClientConn.transfers[fileTransfer.Type], t.ReferenceNumber)
 827                 fileTransfer.ClientConn.transfersMU.Unlock()
 828         }()
 829
 830         rLogger := s.Logger.With(
 831                 "remoteAddr", ctx.Value(contextKeyReq).(requestCtx).remoteAddr,
 832                 "login", fileTransfer.ClientConn.Account.Login,
 833                 "name", string(fileTransfer.ClientConn.UserName),
 834         )
 835
 836         fullPath, err := readPath(s.Config.FileRoot, fileTransfer.FilePath, fileTransfer.FileName)
 837         if err != nil {
 838                 return err
 839         }
 840
 841         switch fileTransfer.Type {
 842         case bannerDownload:
 843                 if err := s.bannerDownload(rwc); err != nil {
 844                         return err
 845                 }
 846         case FileDownload:
 847                 s.Stats.DownloadCounter += 1
 848                 s.Stats.DownloadsInProgress += 1
 849                 defer func() {
 850                         s.Stats.DownloadsInProgress -= 1
 851                 }()
 852
 853                 var dataOffset int64
 854                 if fileTransfer.fileResumeData != nil {
 855                         dataOffset = int64(binary.BigEndian.Uint32(fileTransfer.fileResumeData.ForkInfoList[0].DataSize[:]))
 856                 }
 857
 858                 fw, err := newFileWrapper(s.FS, fullPath, 0)
 859                 if err != nil {
 860                         return err
 861                 }
 862
 863                 rLogger.Infow("File download started", "filePath", fullPath)
 864
 865                 // if file transfer options are included, that means this is a "quick preview" request from a 1.5+ client
 866                 if fileTransfer.options == nil {
 867                         _, err = io.Copy(rwc, fw.ffo)
 868                         if err != nil {
 869                                 return err
 870                         }
 871                 }
 872
 873                 file, err := fw.dataForkReader()
 874                 if err != nil {
 875                         return err
 876                 }
 877
 878                 br := bufio.NewReader(file)
 879                 if _, err := br.Discard(int(dataOffset)); err != nil {
 880                         return err
 881                 }
 882
 883                 if _, err = io.Copy(rwc, io.TeeReader(br, fileTransfer.bytesSentCounter)); err != nil {
 884                         return err
 885                 }
 886
 887                 // if the client requested to resume transfer, do not send the resource fork header, or it will be appended into the fileWrapper data
 888                 if fileTransfer.fileResumeData == nil {
 889                         err = binary.Write(rwc, binary.BigEndian, fw.rsrcForkHeader())
 890                         if err != nil {
 891                                 return err
 892                         }
 893                 }
 894
 895                 rFile, err := fw.rsrcForkFile()
 896                 if err != nil {
 897                         return nil
 898                 }
 899
 900                 if _, err = io.Copy(rwc, io.TeeReader(rFile, fileTransfer.bytesSentCounter)); err != nil {
 901                         return err
 902                 }
 903
 904         case FileUpload:
 905                 s.Stats.UploadCounter += 1
 906                 s.Stats.UploadsInProgress += 1
 907                 defer func() { s.Stats.UploadsInProgress -= 1 }()
 908
 909                 var file *os.File
 910
 911                 // A file upload has three possible cases:
 912                 // 1) Upload a new file
 913                 // 2) Resume a partially transferred file
 914                 // 3) Replace a fully uploaded file
 915                 //  We have to infer which case applies by inspecting what is already on the filesystem
 916
 917                 // 1) Check for existing file:
 918                 _, err = os.Stat(fullPath)
 919                 if err == nil {
 920                         return errors.New("existing file found at " + fullPath)
 921                 }
 922                 if errors.Is(err, fs.ErrNotExist) {
 923                         // If not found, open or create a new .incomplete file
 924                         file, err = os.OpenFile(fullPath+incompleteFileSuffix, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0644)
 925                         if err != nil {
 926                                 return err
 927                         }
 928                 }
 929
 930                 f, err := newFileWrapper(s.FS, fullPath, 0)
 931                 if err != nil {
 932                         return err
 933                 }
 934
 935                 rLogger.Infow("File upload started", "dstFile", fullPath)
 936
 937                 rForkWriter := io.Discard
 938                 iForkWriter := io.Discard
 939                 if s.Config.PreserveResourceForks {
 940                         rForkWriter, err = f.rsrcForkWriter()
 941                         if err != nil {
 942                                 return err
 943                         }
 944
 945                         iForkWriter, err = f.infoForkWriter()
 946                         if err != nil {
 947                                 return err
 948                         }
 949                 }
 950
 951                 if err := receiveFile(rwc, file, rForkWriter, iForkWriter, fileTransfer.bytesSentCounter); err != nil {
 952                         s.Logger.Error(err)
 953                 }
 954
 955                 if err := file.Close(); err != nil {
 956                         return err
 957                 }
 958
 959                 if err := s.FS.Rename(fullPath+".incomplete", fullPath); err != nil {
 960                         return err
 961                 }
 962
 963                 rLogger.Infow("File upload complete", "dstFile", fullPath)
 964
 965         case FolderDownload:
 966                 s.Stats.DownloadCounter += 1
 967                 s.Stats.DownloadsInProgress += 1
 968                 defer func() { s.Stats.DownloadsInProgress -= 1 }()
 969
 970                 // Folder Download flow:
 971                 // 1. Get filePath from the transfer
 972                 // 2. Iterate over files
 973                 // 3. For each fileWrapper:
 974                 //       Send fileWrapper header to client
 975                 // The client can reply in 3 ways:
 976                 //
 977                 // 1. If type is an odd number (unknown type?), or fileWrapper download for the current fileWrapper is completed:
 978                 //              client sends []byte{0x00, 0x03} to tell the server to continue to the next fileWrapper
 979                 //
 980                 // 2. If download of a fileWrapper is to be resumed:
 981                 //              client sends:
 982                 //                      []byte{0x00, 0x02} // download folder action
 983                 //                      [2]byte // Resume data size
 984                 //                      []byte fileWrapper resume data (see myField_FileResumeData)
 985                 //
 986                 // 3. Otherwise, download of the fileWrapper is requested and client sends []byte{0x00, 0x01}
 987                 //
 988                 // When download is requested (case 2 or 3), server replies with:
 989                 //                      [4]byte - fileWrapper size
 990                 //                      []byte  - Flattened File Object
 991                 //
 992                 // After every fileWrapper download, client could request next fileWrapper with:
 993                 //                      []byte{0x00, 0x03}
 994                 //
 995                 // This notifies the server to send the next item header
 996
 997                 basePathLen := len(fullPath)
 998
 999                 rLogger.Infow("Start folder download", "path", fullPath)
1000
1001                 nextAction := make([]byte, 2)
1002                 if _, err := io.ReadFull(rwc, nextAction); err != nil {
1003                         return err
1004                 }
1005
1006                 i := 0
1007                 err = filepath.Walk(fullPath+"/", func(path string, info os.FileInfo, err error) error {
1008                         s.Stats.DownloadCounter += 1
1009                         i += 1
1010
1011                         if err != nil {
1012                                 return err
1013                         }
1014
1015                         // skip dot files
1016                         if strings.HasPrefix(info.Name(), ".") {
1017                                 return nil
1018                         }
1019
1020                         hlFile, err := newFileWrapper(s.FS, path, 0)
1021                         if err != nil {
1022                                 return err
1023                         }
1024
1025                         subPath := path[basePathLen+1:]
1026                         rLogger.Debugw("Sending fileheader", "i", i, "path", path, "fullFilePath", fullPath, "subPath", subPath, "IsDir", info.IsDir())
1027
1028                         if i == 1 {
1029                                 return nil
1030                         }
1031
1032                         fileHeader := NewFileHeader(subPath, info.IsDir())
1033                         if _, err := io.Copy(rwc, &fileHeader); err != nil {
1034                                 return fmt.Errorf("error sending file header: %w", err)
1035                         }
1036
1037                         // Read the client's Next Action request
1038                         if _, err := io.ReadFull(rwc, nextAction); err != nil {
1039                                 return err
1040                         }
1041
1042                         rLogger.Debugw("Client folder download action", "action", fmt.Sprintf("%X", nextAction[0:2]))
1043
1044                         var dataOffset int64
1045
1046                         switch nextAction[1] {
1047                         case dlFldrActionResumeFile:
1048                                 // get size of resumeData
1049                                 resumeDataByteLen := make([]byte, 2)
1050                                 if _, err := io.ReadFull(rwc, resumeDataByteLen); err != nil {
1051                                         return err
1052                                 }
1053
1054                                 resumeDataLen := binary.BigEndian.Uint16(resumeDataByteLen)
1055                                 resumeDataBytes := make([]byte, resumeDataLen)
1056                                 if _, err := io.ReadFull(rwc, resumeDataBytes); err != nil {
1057                                         return err
1058                                 }
1059
1060                                 var frd FileResumeData
1061                                 if err := frd.UnmarshalBinary(resumeDataBytes); err != nil {
1062                                         return err
1063                                 }
1064                                 dataOffset = int64(binary.BigEndian.Uint32(frd.ForkInfoList[0].DataSize[:]))
1065                         case dlFldrActionNextFile:
1066                                 // client asked to skip this file
1067                                 return nil
1068                         }
1069
1070                         if info.IsDir() {
1071                                 return nil
1072                         }
1073
1074                         rLogger.Infow("File download started",
1075                                 "fileName", info.Name(),
1076                                 "TransferSize", fmt.Sprintf("%x", hlFile.ffo.TransferSize(dataOffset)),
1077                         )
1078
1079                         // Send file size to client
1080                         if _, err := rwc.Write(hlFile.ffo.TransferSize(dataOffset)); err != nil {
1081                                 s.Logger.Error(err)
1082                                 return err
1083                         }
1084
1085                         // Send ffo bytes to client
1086                         _, err = io.Copy(rwc, hlFile.ffo)
1087                         if err != nil {
1088                                 return err
1089                         }
1090
1091                         file, err := s.FS.Open(path)
1092                         if err != nil {
1093                                 return err
1094                         }
1095
1096                         // wr := bufio.NewWriterSize(rwc, 1460)
1097                         if _, err = io.Copy(rwc, io.TeeReader(file, fileTransfer.bytesSentCounter)); err != nil {
1098                                 return err
1099                         }
1100
1101                         if nextAction[1] != 2 && hlFile.ffo.FlatFileHeader.ForkCount[1] == 3 {
1102                                 err = binary.Write(rwc, binary.BigEndian, hlFile.rsrcForkHeader())
1103                                 if err != nil {
1104                                         return err
1105                                 }
1106
1107                                 rFile, err := hlFile.rsrcForkFile()
1108                                 if err != nil {
1109                                         return err
1110                                 }
1111
1112                                 if _, err = io.Copy(rwc, io.TeeReader(rFile, fileTransfer.bytesSentCounter)); err != nil {
1113                                         return err
1114                                 }
1115                         }
1116
1117                         // Read the client's Next Action request.  This is always 3, I think?
1118                         if _, err := io.ReadFull(rwc, nextAction); err != nil {
1119                                 return err
1120                         }
1121
1122                         return nil
1123                 })
1124
1125                 if err != nil {
1126                         return err
1127                 }
1128
1129         case FolderUpload:
1130                 s.Stats.UploadCounter += 1
1131                 s.Stats.UploadsInProgress += 1
1132                 defer func() { s.Stats.UploadsInProgress -= 1 }()
1133                 rLogger.Infow(
1134                         "Folder upload started",
1135                         "dstPath", fullPath,
1136                         "TransferSize", binary.BigEndian.Uint32(fileTransfer.TransferSize),
1137                         "FolderItemCount", fileTransfer.FolderItemCount,
1138                 )
1139
1140                 // Check if the target folder exists.  If not, create it.
1141                 if _, err := s.FS.Stat(fullPath); os.IsNotExist(err) {
1142                         if err := s.FS.Mkdir(fullPath, 0777); err != nil {
1143                                 return err
1144                         }
1145                 }
1146
1147                 // Begin the folder upload flow by sending the "next file action" to client
1148                 if _, err := rwc.Write([]byte{0, dlFldrActionNextFile}); err != nil {
1149                         return err
1150                 }
1151
1152                 fileSize := make([]byte, 4)
1153
1154                 for i := 0; i < fileTransfer.ItemCount(); i++ {
1155                         s.Stats.UploadCounter += 1
1156
1157                         var fu folderUpload
1158                         if _, err := io.ReadFull(rwc, fu.DataSize[:]); err != nil {
1159                                 return err
1160                         }
1161                         if _, err := io.ReadFull(rwc, fu.IsFolder[:]); err != nil {
1162                                 return err
1163                         }
1164                         if _, err := io.ReadFull(rwc, fu.PathItemCount[:]); err != nil {
1165                                 return err
1166                         }
1167
1168                         fu.FileNamePath = make([]byte, binary.BigEndian.Uint16(fu.DataSize[:])-4) // -4 to subtract the path separator bytes
1169
1170                         if _, err := io.ReadFull(rwc, fu.FileNamePath); err != nil {
1171                                 return err
1172                         }
1173
1174                         rLogger.Infow(
1175                                 "Folder upload continued",
1176                                 "FormattedPath", fu.FormattedPath(),
1177                                 "IsFolder", fmt.Sprintf("%x", fu.IsFolder),
1178                                 "PathItemCount", binary.BigEndian.Uint16(fu.PathItemCount[:]),
1179                         )
1180
1181                         if fu.IsFolder == [2]byte{0, 1} {
1182                                 if _, err := os.Stat(filepath.Join(fullPath, fu.FormattedPath())); os.IsNotExist(err) {
1183                                         if err := os.Mkdir(filepath.Join(fullPath, fu.FormattedPath()), 0777); err != nil {
1184                                                 return err
1185                                         }
1186                                 }
1187
1188                                 // Tell client to send next file
1189                                 if _, err := rwc.Write([]byte{0, dlFldrActionNextFile}); err != nil {
1190                                         return err
1191                                 }
1192                         } else {
1193                                 nextAction := dlFldrActionSendFile
1194
1195                                 // Check if we have the full file already.  If so, send dlFldrAction_NextFile to client to skip.
1196                                 _, err = os.Stat(filepath.Join(fullPath, fu.FormattedPath()))
1197                                 if err != nil && !errors.Is(err, fs.ErrNotExist) {
1198                                         return err
1199                                 }
1200                                 if err == nil {
1201                                         nextAction = dlFldrActionNextFile
1202                                 }
1203
1204                                 //  Check if we have a partial file already.  If so, send dlFldrAction_ResumeFile to client to resume upload.
1205                                 incompleteFile, err := os.Stat(filepath.Join(fullPath, fu.FormattedPath()+incompleteFileSuffix))
1206                                 if err != nil && !errors.Is(err, fs.ErrNotExist) {
1207                                         return err
1208                                 }
1209                                 if err == nil {
1210                                         nextAction = dlFldrActionResumeFile
1211                                 }
1212
1213                                 if _, err := rwc.Write([]byte{0, uint8(nextAction)}); err != nil {
1214                                         return err
1215                                 }
1216
1217                                 switch nextAction {
1218                                 case dlFldrActionNextFile:
1219                                         continue
1220                                 case dlFldrActionResumeFile:
1221                                         offset := make([]byte, 4)
1222                                         binary.BigEndian.PutUint32(offset, uint32(incompleteFile.Size()))
1223
1224                                         file, err := os.OpenFile(fullPath+"/"+fu.FormattedPath()+incompleteFileSuffix, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
1225                                         if err != nil {
1226                                                 return err
1227                                         }
1228
1229                                         fileResumeData := NewFileResumeData([]ForkInfoList{*NewForkInfoList(offset)})
1230
1231                                         b, _ := fileResumeData.BinaryMarshal()
1232
1233                                         bs := make([]byte, 2)
1234                                         binary.BigEndian.PutUint16(bs, uint16(len(b)))
1235
1236                                         if _, err := rwc.Write(append(bs, b...)); err != nil {
1237                                                 return err
1238                                         }
1239
1240                                         if _, err := io.ReadFull(rwc, fileSize); err != nil {
1241                                                 return err
1242                                         }
1243
1244                                         if err := receiveFile(rwc, file, io.Discard, io.Discard, fileTransfer.bytesSentCounter); err != nil {
1245                                                 s.Logger.Error(err)
1246                                         }
1247
1248                                         err = os.Rename(fullPath+"/"+fu.FormattedPath()+".incomplete", fullPath+"/"+fu.FormattedPath())
1249                                         if err != nil {
1250                                                 return err
1251                                         }
1252
1253                                 case dlFldrActionSendFile:
1254                                         if _, err := io.ReadFull(rwc, fileSize); err != nil {
1255                                                 return err
1256                                         }
1257
1258                                         filePath := filepath.Join(fullPath, fu.FormattedPath())
1259
1260                                         hlFile, err := newFileWrapper(s.FS, filePath, 0)
1261                                         if err != nil {
1262                                                 return err
1263                                         }
1264
1265                                         rLogger.Infow("Starting file transfer", "path", filePath, "fileNum", i+1, "fileSize", binary.BigEndian.Uint32(fileSize))
1266
1267                                         incWriter, err := hlFile.incFileWriter()
1268                                         if err != nil {
1269                                                 return err
1270                                         }
1271
1272                                         rForkWriter := io.Discard
1273                                         iForkWriter := io.Discard
1274                                         if s.Config.PreserveResourceForks {
1275                                                 iForkWriter, err = hlFile.infoForkWriter()
1276                                                 if err != nil {
1277                                                         return err
1278                                                 }
1279
1280                                                 rForkWriter, err = hlFile.rsrcForkWriter()
1281                                                 if err != nil {
1282                                                         return err
1283                                                 }
1284                                         }
1285                                         if err := receiveFile(rwc, incWriter, rForkWriter, iForkWriter, fileTransfer.bytesSentCounter); err != nil {
1286                                                 return err
1287                                         }
1288
1289                                         if err := os.Rename(filePath+".incomplete", filePath); err != nil {
1290                                                 return err
1291                                         }
1292                                 }
1293
1294                                 // Tell client to send next fileWrapper
1295                                 if _, err := rwc.Write([]byte{0, dlFldrActionNextFile}); err != nil {
1296                                         return err
1297                                 }
1298                         }
1299                 }
1300                 rLogger.Infof("Folder upload complete")
1301         }
1302
1303         return nil
1304 }