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