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                 user := User{
 498                         ID:    *c.ID,
 499                         Icon:  c.Icon,
 500                         Flags: c.Flags,
 501                         Name:  string(c.UserName),
 502                 }
 503                 connectedUsers = append(connectedUsers, NewField(FieldUsernameWithInfo, user.Payload()))
 504         }
 505         return connectedUsers
 506 }
 507
 508 func (s *Server) loadBanList(path string) error {
 509         fh, err := os.Open(path)
 510         if err != nil {
 511                 return err
 512         }
 513         decoder := yaml.NewDecoder(fh)
 514
 515         return decoder.Decode(s.banList)
 516 }
 517
 518 // loadThreadedNews loads the threaded news data from disk
 519 func (s *Server) loadThreadedNews(threadedNewsPath string) error {
 520         fh, err := os.Open(threadedNewsPath)
 521         if err != nil {
 522                 return err
 523         }
 524         decoder := yaml.NewDecoder(fh)
 525
 526         return decoder.Decode(s.ThreadedNews)
 527 }
 528
 529 // loadAccounts loads account data from disk
 530 func (s *Server) loadAccounts(userDir string) error {
 531         matches, err := filepath.Glob(filepath.Join(userDir, "*.yaml"))
 532         if err != nil {
 533                 return err
 534         }
 535
 536         if len(matches) == 0 {
 537                 return errors.New("no user accounts found in " + userDir)
 538         }
 539
 540         for _, file := range matches {
 541                 fh, err := s.FS.Open(file)
 542                 if err != nil {
 543                         return err
 544                 }
 545
 546                 account := Account{}
 547                 decoder := yaml.NewDecoder(fh)
 548                 if err = decoder.Decode(&account); err != nil {
 549                         return fmt.Errorf("error loading account %s: %w", file, err)
 550                 }
 551
 552                 s.Accounts[account.Login] = &account
 553         }
 554         return nil
 555 }
 556
 557 func (s *Server) loadConfig(path string) error {
 558         fh, err := s.FS.Open(path)
 559         if err != nil {
 560                 return err
 561         }
 562
 563         decoder := yaml.NewDecoder(fh)
 564         err = decoder.Decode(s.Config)
 565         if err != nil {
 566                 return err
 567         }
 568
 569         validate := validator.New()
 570         err = validate.Struct(s.Config)
 571         if err != nil {
 572                 return err
 573         }
 574         return nil
 575 }
 576
 577 // handleNewConnection takes a new net.Conn and performs the initial login sequence
 578 func (s *Server) handleNewConnection(ctx context.Context, rwc io.ReadWriteCloser, remoteAddr string) error {
 579         defer dontPanic(s.Logger)
 580
 581         if err := Handshake(rwc); err != nil {
 582                 return err
 583         }
 584
 585         // Create a new scanner for parsing incoming bytes into transaction tokens
 586         scanner := bufio.NewScanner(rwc)
 587         scanner.Split(transactionScanner)
 588
 589         scanner.Scan()
 590
 591         // Make a new []byte slice and copy the scanner bytes to it.  This is critical to avoid a data race as the
 592         // scanner re-uses the buffer for subsequent scans.
 593         buf := make([]byte, len(scanner.Bytes()))
 594         copy(buf, scanner.Bytes())
 595
 596         var clientLogin Transaction
 597         if _, err := clientLogin.Write(buf); err != nil {
 598                 return err
 599         }
 600
 601         // check if remoteAddr is present in the ban list
 602         if banUntil, ok := s.banList[strings.Split(remoteAddr, ":")[0]]; ok {
 603                 // permaban
 604                 if banUntil == nil {
 605                         t := NewTransaction(
 606                                 TranServerMsg,
 607                                 &[]byte{0, 0},
 608                                 NewField(FieldData, []byte("You are permanently banned on this server")),
 609                                 NewField(FieldChatOptions, []byte{0, 0}),
 610                         )
 611
 612                         b, err := t.MarshalBinary()
 613                         if err != nil {
 614                                 return err
 615                         }
 616
 617                         _, err = rwc.Write(b)
 618                         if err != nil {
 619                                 return err
 620                         }
 621
 622                         time.Sleep(1 * time.Second)
 623                         return nil
 624                 }
 625
 626                 // temporary ban
 627                 if time.Now().Before(*banUntil) {
 628                         t := NewTransaction(
 629                                 TranServerMsg,
 630                                 &[]byte{0, 0},
 631                                 NewField(FieldData, []byte("You are temporarily banned on this server")),
 632                                 NewField(FieldChatOptions, []byte{0, 0}),
 633                         )
 634                         b, err := t.MarshalBinary()
 635                         if err != nil {
 636                                 return err
 637                         }
 638
 639                         _, err = rwc.Write(b)
 640                         if err != nil {
 641                                 return err
 642                         }
 643
 644                         time.Sleep(1 * time.Second)
 645                         return nil
 646                 }
 647         }
 648
 649         c := s.NewClientConn(rwc, remoteAddr)
 650         defer c.Disconnect()
 651
 652         encodedLogin := clientLogin.GetField(FieldUserLogin).Data
 653         encodedPassword := clientLogin.GetField(FieldUserPassword).Data
 654         c.Version = clientLogin.GetField(FieldVersion).Data
 655
 656         var login string
 657         for _, char := range encodedLogin {
 658                 login += string(rune(255 - uint(char)))
 659         }
 660         if login == "" {
 661                 login = GuestAccount
 662         }
 663
 664         c.logger = s.Logger.With("remoteAddr", remoteAddr, "login", login)
 665
 666         // If authentication fails, send error reply and close connection
 667         if !c.Authenticate(login, encodedPassword) {
 668                 t := c.NewErrReply(&clientLogin, "Incorrect login.")
 669                 b, err := t.MarshalBinary()
 670                 if err != nil {
 671                         return err
 672                 }
 673                 if _, err := rwc.Write(b); err != nil {
 674                         return err
 675                 }
 676
 677                 c.logger.Infow("Login failed", "clientVersion", fmt.Sprintf("%x", c.Version))
 678
 679                 return nil
 680         }
 681
 682         if clientLogin.GetField(FieldUserIconID).Data != nil {
 683                 c.Icon = clientLogin.GetField(FieldUserIconID).Data
 684         }
 685
 686         c.Account = c.Server.Accounts[login]
 687
 688         if clientLogin.GetField(FieldUserName).Data != nil {
 689                 if c.Authorize(accessAnyName) {
 690                         c.UserName = clientLogin.GetField(FieldUserName).Data
 691                 } else {
 692                         c.UserName = []byte(c.Account.Name)
 693                 }
 694         }
 695
 696         if c.Authorize(accessDisconUser) {
 697                 c.Flags = []byte{0, 2}
 698         }
 699
 700         s.outbox <- c.NewReply(&clientLogin,
 701                 NewField(FieldVersion, []byte{0x00, 0xbe}),
 702                 NewField(FieldCommunityBannerID, []byte{0, 0}),
 703                 NewField(FieldServerName, []byte(s.Config.Name)),
 704         )
 705
 706         // Send user access privs so client UI knows how to behave
 707         c.Server.outbox <- *NewTransaction(TranUserAccess, c.ID, NewField(FieldUserAccess, c.Account.Access[:]))
 708
 709         // Accounts with accessNoAgreement do not receive the server agreement on login.  The behavior is different between
 710         // client versions.  For 1.2.3 client, we do not send TranShowAgreement.  For other client versions, we send
 711         // TranShowAgreement but with the NoServerAgreement field set to 1.
 712         if c.Authorize(accessNoAgreement) {
 713                 // If client version is nil, then the client uses the 1.2.3 login behavior
 714                 if c.Version != nil {
 715                         c.Server.outbox <- *NewTransaction(TranShowAgreement, c.ID, NewField(FieldNoServerAgreement, []byte{1}))
 716                 }
 717         } else {
 718                 c.Server.outbox <- *NewTransaction(TranShowAgreement, c.ID, NewField(FieldData, s.Agreement))
 719         }
 720
 721         // If the client has provided a username as part of the login, we can infer that it is using the 1.2.3 login
 722         // flow and not the 1.5+ flow.
 723         if len(c.UserName) != 0 {
 724                 // Add the client username to the logger.  For 1.5+ clients, we don't have this information yet as it comes as
 725                 // part of TranAgreed
 726                 c.logger = c.logger.With("name", string(c.UserName))
 727
 728                 c.logger.Infow("Login successful", "clientVersion", "Not sent (probably 1.2.3)")
 729
 730                 // Notify other clients on the server that the new user has logged in.  For 1.5+ clients we don't have this
 731                 // information yet, so we do it in TranAgreed instead
 732                 for _, t := range c.notifyOthers(
 733                         *NewTransaction(
 734                                 TranNotifyChangeUser, nil,
 735                                 NewField(FieldUserName, c.UserName),
 736                                 NewField(FieldUserID, *c.ID),
 737                                 NewField(FieldUserIconID, c.Icon),
 738                                 NewField(FieldUserFlags, c.Flags),
 739                         ),
 740                 ) {
 741                         c.Server.outbox <- t
 742                 }
 743         }
 744
 745         c.Server.Stats.ConnectionCounter += 1
 746         if len(s.Clients) > c.Server.Stats.ConnectionPeak {
 747                 c.Server.Stats.ConnectionPeak = len(s.Clients)
 748         }
 749
 750         // Scan for new transactions and handle them as they come in.
 751         for scanner.Scan() {
 752                 // Make a new []byte slice and copy the scanner bytes to it.  This is critical to avoid a data race as the
 753                 // scanner re-uses the buffer for subsequent scans.
 754                 buf := make([]byte, len(scanner.Bytes()))
 755                 copy(buf, scanner.Bytes())
 756
 757                 var t Transaction
 758                 if _, err := t.Write(buf); err != nil {
 759                         return err
 760                 }
 761
 762                 if err := c.handleTransaction(t); err != nil {
 763                         c.logger.Errorw("Error handling transaction", "err", err)
 764                 }
 765         }
 766         return nil
 767 }
 768
 769 func (s *Server) NewPrivateChat(cc *ClientConn) []byte {
 770         s.PrivateChatsMu.Lock()
 771         defer s.PrivateChatsMu.Unlock()
 772
 773         randID := make([]byte, 4)
 774         rand.Read(randID)
 775         data := binary.BigEndian.Uint32(randID)
 776
 777         s.PrivateChats[data] = &PrivateChat{
 778                 ClientConn: make(map[uint16]*ClientConn),
 779         }
 780         s.PrivateChats[data].ClientConn[cc.uint16ID()] = cc
 781
 782         return randID
 783 }
 784
 785 const dlFldrActionSendFile = 1
 786 const dlFldrActionResumeFile = 2
 787 const dlFldrActionNextFile = 3
 788
 789 // handleFileTransfer receives a client net.Conn from the file transfer server, performs the requested transfer type, then closes the connection
 790 func (s *Server) handleFileTransfer(ctx context.Context, rwc io.ReadWriter) error {
 791         defer dontPanic(s.Logger)
 792
 793         txBuf := make([]byte, 16)
 794         if _, err := io.ReadFull(rwc, txBuf); err != nil {
 795                 return err
 796         }
 797
 798         var t transfer
 799         if _, err := t.Write(txBuf); err != nil {
 800                 return err
 801         }
 802
 803         defer func() {
 804                 s.mux.Lock()
 805                 delete(s.fileTransfers, t.ReferenceNumber)
 806                 s.mux.Unlock()
 807
 808                 // Wait a few seconds before closing the connection: this is a workaround for problems
 809                 // observed with Windows clients where the client must initiate close of the TCP connection before
 810                 // the server does.  This is gross and seems unnecessary.  TODO: Revisit?
 811                 time.Sleep(3 * time.Second)
 812         }()
 813
 814         s.mux.Lock()
 815         fileTransfer, ok := s.fileTransfers[t.ReferenceNumber]
 816         s.mux.Unlock()
 817         if !ok {
 818                 return errors.New("invalid transaction ID")
 819         }
 820
 821         defer func() {
 822                 fileTransfer.ClientConn.transfersMU.Lock()
 823                 delete(fileTransfer.ClientConn.transfers[fileTransfer.Type], t.ReferenceNumber)
 824                 fileTransfer.ClientConn.transfersMU.Unlock()
 825         }()
 826
 827         rLogger := s.Logger.With(
 828                 "remoteAddr", ctx.Value(contextKeyReq).(requestCtx).remoteAddr,
 829                 "login", fileTransfer.ClientConn.Account.Login,
 830                 "name", string(fileTransfer.ClientConn.UserName),
 831         )
 832
 833         fullPath, err := readPath(s.Config.FileRoot, fileTransfer.FilePath, fileTransfer.FileName)
 834         if err != nil {
 835                 return err
 836         }
 837
 838         switch fileTransfer.Type {
 839         case bannerDownload:
 840                 if err := s.bannerDownload(rwc); err != nil {
 841                         return err
 842                 }
 843         case FileDownload:
 844                 s.Stats.DownloadCounter += 1
 845                 s.Stats.DownloadsInProgress += 1
 846                 defer func() {
 847                         s.Stats.DownloadsInProgress -= 1
 848                 }()
 849
 850                 var dataOffset int64
 851                 if fileTransfer.fileResumeData != nil {
 852                         dataOffset = int64(binary.BigEndian.Uint32(fileTransfer.fileResumeData.ForkInfoList[0].DataSize[:]))
 853                 }
 854
 855                 fw, err := newFileWrapper(s.FS, fullPath, 0)
 856                 if err != nil {
 857                         return err
 858                 }
 859
 860                 rLogger.Infow("File download started", "filePath", fullPath)
 861
 862                 // if file transfer options are included, that means this is a "quick preview" request from a 1.5+ client
 863                 if fileTransfer.options == nil {
 864                         // Start by sending flat file object to client
 865                         if _, err := rwc.Write(fw.ffo.BinaryMarshal()); err != nil {
 866                                 return err
 867                         }
 868                 }
 869
 870                 file, err := fw.dataForkReader()
 871                 if err != nil {
 872                         return err
 873                 }
 874
 875                 br := bufio.NewReader(file)
 876                 if _, err := br.Discard(int(dataOffset)); err != nil {
 877                         return err
 878                 }
 879
 880                 if _, err = io.Copy(rwc, io.TeeReader(br, fileTransfer.bytesSentCounter)); err != nil {
 881                         return err
 882                 }
 883
 884                 // if the client requested to resume transfer, do not send the resource fork header, or it will be appended into the fileWrapper data
 885                 if fileTransfer.fileResumeData == nil {
 886                         err = binary.Write(rwc, binary.BigEndian, fw.rsrcForkHeader())
 887                         if err != nil {
 888                                 return err
 889                         }
 890                 }
 891
 892                 rFile, err := fw.rsrcForkFile()
 893                 if err != nil {
 894                         return nil
 895                 }
 896
 897                 if _, err = io.Copy(rwc, io.TeeReader(rFile, fileTransfer.bytesSentCounter)); err != nil {
 898                         return err
 899                 }
 900
 901         case FileUpload:
 902                 s.Stats.UploadCounter += 1
 903                 s.Stats.UploadsInProgress += 1
 904                 defer func() { s.Stats.UploadsInProgress -= 1 }()
 905
 906                 var file *os.File
 907
 908                 // A file upload has three possible cases:
 909                 // 1) Upload a new file
 910                 // 2) Resume a partially transferred file
 911                 // 3) Replace a fully uploaded file
 912                 //  We have to infer which case applies by inspecting what is already on the filesystem
 913
 914                 // 1) Check for existing file:
 915                 _, err = os.Stat(fullPath)
 916                 if err == nil {
 917                         return errors.New("existing file found at " + fullPath)
 918                 }
 919                 if errors.Is(err, fs.ErrNotExist) {
 920                         // If not found, open or create a new .incomplete file
 921                         file, err = os.OpenFile(fullPath+incompleteFileSuffix, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0644)
 922                         if err != nil {
 923                                 return err
 924                         }
 925                 }
 926
 927                 f, err := newFileWrapper(s.FS, fullPath, 0)
 928                 if err != nil {
 929                         return err
 930                 }
 931
 932                 rLogger.Infow("File upload started", "dstFile", fullPath)
 933
 934                 rForkWriter := io.Discard
 935                 iForkWriter := io.Discard
 936                 if s.Config.PreserveResourceForks {
 937                         rForkWriter, err = f.rsrcForkWriter()
 938                         if err != nil {
 939                                 return err
 940                         }
 941
 942                         iForkWriter, err = f.infoForkWriter()
 943                         if err != nil {
 944                                 return err
 945                         }
 946                 }
 947
 948                 if err := receiveFile(rwc, file, rForkWriter, iForkWriter, fileTransfer.bytesSentCounter); err != nil {
 949                         s.Logger.Error(err)
 950                 }
 951
 952                 if err := file.Close(); err != nil {
 953                         return err
 954                 }
 955
 956                 if err := s.FS.Rename(fullPath+".incomplete", fullPath); err != nil {
 957                         return err
 958                 }
 959
 960                 rLogger.Infow("File upload complete", "dstFile", fullPath)
 961
 962         case FolderDownload:
 963                 s.Stats.DownloadCounter += 1
 964                 s.Stats.DownloadsInProgress += 1
 965                 defer func() { s.Stats.DownloadsInProgress -= 1 }()
 966
 967                 // Folder Download flow:
 968                 // 1. Get filePath from the transfer
 969                 // 2. Iterate over files
 970                 // 3. For each fileWrapper:
 971                 //       Send fileWrapper header to client
 972                 // The client can reply in 3 ways:
 973                 //
 974                 // 1. If type is an odd number (unknown type?), or fileWrapper download for the current fileWrapper is completed:
 975                 //              client sends []byte{0x00, 0x03} to tell the server to continue to the next fileWrapper
 976                 //
 977                 // 2. If download of a fileWrapper is to be resumed:
 978                 //              client sends:
 979                 //                      []byte{0x00, 0x02} // download folder action
 980                 //                      [2]byte // Resume data size
 981                 //                      []byte fileWrapper resume data (see myField_FileResumeData)
 982                 //
 983                 // 3. Otherwise, download of the fileWrapper is requested and client sends []byte{0x00, 0x01}
 984                 //
 985                 // When download is requested (case 2 or 3), server replies with:
 986                 //                      [4]byte - fileWrapper size
 987                 //                      []byte  - Flattened File Object
 988                 //
 989                 // After every fileWrapper download, client could request next fileWrapper with:
 990                 //                      []byte{0x00, 0x03}
 991                 //
 992                 // This notifies the server to send the next item header
 993
 994                 basePathLen := len(fullPath)
 995
 996                 rLogger.Infow("Start folder download", "path", fullPath)
 997
 998                 nextAction := make([]byte, 2)
 999                 if _, err := io.ReadFull(rwc, nextAction); err != nil {
1000                         return err
1001                 }
1002
1003                 i := 0
1004                 err = filepath.Walk(fullPath+"/", func(path string, info os.FileInfo, err error) error {
1005                         s.Stats.DownloadCounter += 1
1006                         i += 1
1007
1008                         if err != nil {
1009                                 return err
1010                         }
1011
1012                         // skip dot files
1013                         if strings.HasPrefix(info.Name(), ".") {
1014                                 return nil
1015                         }
1016
1017                         hlFile, err := newFileWrapper(s.FS, path, 0)
1018                         if err != nil {
1019                                 return err
1020                         }
1021
1022                         subPath := path[basePathLen+1:]
1023                         rLogger.Debugw("Sending fileheader", "i", i, "path", path, "fullFilePath", fullPath, "subPath", subPath, "IsDir", info.IsDir())
1024
1025                         if i == 1 {
1026                                 return nil
1027                         }
1028
1029                         fileHeader := NewFileHeader(subPath, info.IsDir())
1030
1031                         // Send the fileWrapper header to client
1032                         if _, err := rwc.Write(fileHeader.Payload()); err != nil {
1033                                 s.Logger.Errorf("error sending file header: %v", err)
1034                                 return 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                         if _, err := rwc.Write(hlFile.ffo.BinaryMarshal()); err != nil {
1087                                 s.Logger.Error(err)
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 }