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

   1 package hotline
   2
   3 import (
   4         "bufio"
   5         "bytes"
   6         "context"
   7         "encoding/binary"
   8         "errors"
   9         "fmt"
  10         "github.com/go-playground/validator/v10"
  11         "go.uber.org/zap"
  12         "gopkg.in/yaml.v3"
  13         "io"
  14         "io/fs"
  15         "io/ioutil"
  16         "math/big"
  17         "math/rand"
  18         "net"
  19         "os"
  20         "path"
  21         "path/filepath"
  22         "runtime/debug"
  23         "strings"
  24         "sync"
  25         "time"
  26 )
  27
  28 type contextKey string
  29
  30 var contextKeyReq = contextKey("req")
  31
  32 type requestCtx struct {
  33         remoteAddr string
  34         login      string
  35         name       string
  36 }
  37
  38 const (
  39         userIdleSeconds        = 300 // time in seconds before an inactive user is marked idle
  40         idleCheckInterval      = 10  // time in seconds to check for idle users
  41         trackerUpdateFrequency = 300 // time in seconds between tracker re-registration
  42 )
  43
  44 var nostalgiaVersion = []byte{0, 0, 2, 0x2c} // version ID used by the Nostalgia client
  45
  46 type Server struct {
  47         Port          int
  48         Accounts      map[string]*Account
  49         Agreement     []byte
  50         Clients       map[uint16]*ClientConn
  51         ThreadedNews  *ThreadedNews
  52         FileTransfers map[uint32]*FileTransfer
  53         Config        *Config
  54         ConfigDir     string
  55         Logger        *zap.SugaredLogger
  56         PrivateChats  map[uint32]*PrivateChat
  57         NextGuestID   *uint16
  58         TrackerPassID [4]byte
  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         flatNewsMux sync.Mutex
  67         FlatNews    []byte
  68 }
  69
  70 type PrivateChat struct {
  71         Subject    string
  72         ClientConn map[uint16]*ClientConn
  73 }
  74
  75 func (s *Server) ListenAndServe(ctx context.Context, cancelRoot context.CancelFunc) error {
  76         s.Logger.Infow("Hotline server started",
  77                 "version", VERSION,
  78                 "API port", fmt.Sprintf(":%v", s.Port),
  79                 "Transfer port", fmt.Sprintf(":%v", s.Port+1),
  80         )
  81
  82         var wg sync.WaitGroup
  83
  84         wg.Add(1)
  85         go func() {
  86                 ln, err := net.Listen("tcp", fmt.Sprintf("%s:%v", "", s.Port))
  87                 if err != nil {
  88                         s.Logger.Fatal(err)
  89                 }
  90
  91                 s.Logger.Fatal(s.Serve(ctx, ln))
  92         }()
  93
  94         wg.Add(1)
  95         go func() {
  96                 ln, err := net.Listen("tcp", fmt.Sprintf("%s:%v", "", s.Port+1))
  97                 if err != nil {
  98                         s.Logger.Fatal(err)
  99
 100                 }
 101
 102                 s.Logger.Fatal(s.ServeFileTransfers(ctx, ln))
 103         }()
 104
 105         wg.Wait()
 106
 107         return nil
 108 }
 109
 110 func (s *Server) ServeFileTransfers(ctx context.Context, ln net.Listener) error {
 111         for {
 112                 conn, err := ln.Accept()
 113                 if err != nil {
 114                         return err
 115                 }
 116
 117                 go func() {
 118                         defer func() { _ = conn.Close() }()
 119
 120                         err = s.handleFileTransfer(
 121                                 context.WithValue(ctx, contextKeyReq, requestCtx{
 122                                         remoteAddr: conn.RemoteAddr().String(),
 123                                 }),
 124                                 conn,
 125                         )
 126
 127                         if err != nil {
 128                                 s.Logger.Errorw("file transfer error", "reason", err)
 129                         }
 130                 }()
 131         }
 132 }
 133
 134 func (s *Server) sendTransaction(t Transaction) error {
 135         requestNum := binary.BigEndian.Uint16(t.Type)
 136         clientID, err := byteToInt(*t.clientID)
 137         if err != nil {
 138                 return err
 139         }
 140
 141         s.mux.Lock()
 142         client := s.Clients[uint16(clientID)]
 143         s.mux.Unlock()
 144         if client == nil {
 145                 return fmt.Errorf("invalid client id %v", *t.clientID)
 146         }
 147         userName := string(client.UserName)
 148         login := client.Account.Login
 149
 150         handler := TransactionHandlers[requestNum]
 151
 152         b, err := t.MarshalBinary()
 153         if err != nil {
 154                 return err
 155         }
 156         var n int
 157         if n, err = client.Connection.Write(b); err != nil {
 158                 return err
 159         }
 160         s.Logger.Debugw("Sent Transaction",
 161                 "name", userName,
 162                 "login", login,
 163                 "IsReply", t.IsReply,
 164                 "type", handler.Name,
 165                 "sentBytes", n,
 166                 "remoteAddr", client.RemoteAddr,
 167         )
 168         return nil
 169 }
 170
 171 func (s *Server) Serve(ctx context.Context, ln net.Listener) error {
 172         for {
 173                 conn, err := ln.Accept()
 174                 if err != nil {
 175                         s.Logger.Errorw("error accepting connection", "err", err)
 176                 }
 177
 178                 go func() {
 179                         for {
 180                                 t := <-s.outbox
 181                                 go func() {
 182                                         if err := s.sendTransaction(t); err != nil {
 183                                                 s.Logger.Errorw("error sending transaction", "err", err)
 184                                         }
 185                                 }()
 186                         }
 187                 }()
 188                 go func() {
 189                         if err := s.handleNewConnection(ctx, conn, conn.RemoteAddr().String()); err != nil {
 190                                 s.Logger.Infow("New client connection established", "RemoteAddr", conn.RemoteAddr())
 191                                 if err == io.EOF {
 192                                         s.Logger.Infow("Client disconnected", "RemoteAddr", conn.RemoteAddr())
 193                                 } else {
 194                                         s.Logger.Errorw("error serving request", "RemoteAddr", conn.RemoteAddr(), "err", err)
 195                                 }
 196                         }
 197                 }()
 198         }
 199 }
 200
 201 const (
 202         agreementFile = "Agreement.txt"
 203 )
 204
 205 // NewServer constructs a new Server from a config dir
 206 func NewServer(configDir string, netPort int, logger *zap.SugaredLogger, FS FileStore) (*Server, error) {
 207         server := Server{
 208                 Port:          netPort,
 209                 Accounts:      make(map[string]*Account),
 210                 Config:        new(Config),
 211                 Clients:       make(map[uint16]*ClientConn),
 212                 FileTransfers: make(map[uint32]*FileTransfer),
 213                 PrivateChats:  make(map[uint32]*PrivateChat),
 214                 ConfigDir:     configDir,
 215                 Logger:        logger,
 216                 NextGuestID:   new(uint16),
 217                 outbox:        make(chan Transaction),
 218                 Stats:         &Stats{StartTime: time.Now()},
 219                 ThreadedNews:  &ThreadedNews{},
 220                 FS:            FS,
 221         }
 222
 223         var err error
 224
 225         // generate a new random passID for tracker registration
 226         if _, err := rand.Read(server.TrackerPassID[:]); err != nil {
 227                 return nil, err
 228         }
 229
 230         server.Agreement, err = os.ReadFile(configDir + agreementFile)
 231         if err != nil {
 232                 return nil, err
 233         }
 234
 235         if server.FlatNews, err = os.ReadFile(configDir + "MessageBoard.txt"); err != nil {
 236                 return nil, err
 237         }
 238
 239         if err := server.loadThreadedNews(configDir + "ThreadedNews.yaml"); err != nil {
 240                 return nil, err
 241         }
 242
 243         if err := server.loadConfig(configDir + "config.yaml"); err != nil {
 244                 return nil, err
 245         }
 246
 247         if err := server.loadAccounts(configDir + "Users/"); err != nil {
 248                 return nil, err
 249         }
 250
 251         server.Config.FileRoot = configDir + "Files/"
 252
 253         *server.NextGuestID = 1
 254
 255         if server.Config.EnableTrackerRegistration {
 256                 server.Logger.Infow(
 257                         "Tracker registration enabled",
 258                         "frequency", fmt.Sprintf("%vs", trackerUpdateFrequency),
 259                         "trackers", server.Config.Trackers,
 260                 )
 261
 262                 go func() {
 263                         for {
 264                                 tr := &TrackerRegistration{
 265                                         UserCount:   server.userCount(),
 266                                         PassID:      server.TrackerPassID[:],
 267                                         Name:        server.Config.Name,
 268                                         Description: server.Config.Description,
 269                                 }
 270                                 binary.BigEndian.PutUint16(tr.Port[:], uint16(server.Port))
 271                                 for _, t := range server.Config.Trackers {
 272                                         if err := register(t, tr); err != nil {
 273                                                 server.Logger.Errorw("unable to register with tracker %v", "error", err)
 274                                         }
 275                                         server.Logger.Infow("Sent Tracker registration", "data", tr)
 276                                 }
 277
 278                                 time.Sleep(trackerUpdateFrequency * time.Second)
 279                         }
 280                 }()
 281         }
 282
 283         // Start Client Keepalive go routine
 284         go server.keepaliveHandler()
 285
 286         return &server, nil
 287 }
 288
 289 func (s *Server) userCount() int {
 290         s.mux.Lock()
 291         defer s.mux.Unlock()
 292
 293         return len(s.Clients)
 294 }
 295
 296 func (s *Server) keepaliveHandler() {
 297         for {
 298                 time.Sleep(idleCheckInterval * time.Second)
 299                 s.mux.Lock()
 300
 301                 for _, c := range s.Clients {
 302                         c.IdleTime += idleCheckInterval
 303                         if c.IdleTime > userIdleSeconds && !c.Idle {
 304                                 c.Idle = true
 305
 306                                 flagBitmap := big.NewInt(int64(binary.BigEndian.Uint16(*c.Flags)))
 307                                 flagBitmap.SetBit(flagBitmap, userFlagAway, 1)
 308                                 binary.BigEndian.PutUint16(*c.Flags, uint16(flagBitmap.Int64()))
 309
 310                                 c.sendAll(
 311                                         tranNotifyChangeUser,
 312                                         NewField(fieldUserID, *c.ID),
 313                                         NewField(fieldUserFlags, *c.Flags),
 314                                         NewField(fieldUserName, c.UserName),
 315                                         NewField(fieldUserIconID, *c.Icon),
 316                                 )
 317                         }
 318                 }
 319                 s.mux.Unlock()
 320         }
 321 }
 322
 323 func (s *Server) writeThreadedNews() error {
 324         s.mux.Lock()
 325         defer s.mux.Unlock()
 326
 327         out, err := yaml.Marshal(s.ThreadedNews)
 328         if err != nil {
 329                 return err
 330         }
 331         err = ioutil.WriteFile(
 332                 s.ConfigDir+"ThreadedNews.yaml",
 333                 out,
 334                 0666,
 335         )
 336         return err
 337 }
 338
 339 func (s *Server) NewClientConn(conn net.Conn, remoteAddr string) *ClientConn {
 340         s.mux.Lock()
 341         defer s.mux.Unlock()
 342
 343         clientConn := &ClientConn{
 344                 ID:         &[]byte{0, 0},
 345                 Icon:       &[]byte{0, 0},
 346                 Flags:      &[]byte{0, 0},
 347                 UserName:   []byte{},
 348                 Connection: conn,
 349                 Server:     s,
 350                 Version:    &[]byte{},
 351                 AutoReply:  []byte{},
 352                 Transfers:  make(map[int][]*FileTransfer),
 353                 Agreed:     false,
 354                 RemoteAddr: remoteAddr,
 355         }
 356         *s.NextGuestID++
 357         ID := *s.NextGuestID
 358
 359         binary.BigEndian.PutUint16(*clientConn.ID, ID)
 360         s.Clients[ID] = clientConn
 361
 362         return clientConn
 363 }
 364
 365 // NewUser creates a new user account entry in the server map and config file
 366 func (s *Server) NewUser(login, name, password string, access []byte) error {
 367         s.mux.Lock()
 368         defer s.mux.Unlock()
 369
 370         account := Account{
 371                 Login:    login,
 372                 Name:     name,
 373                 Password: hashAndSalt([]byte(password)),
 374                 Access:   &access,
 375         }
 376         out, err := yaml.Marshal(&account)
 377         if err != nil {
 378                 return err
 379         }
 380         s.Accounts[login] = &account
 381
 382         return s.FS.WriteFile(s.ConfigDir+"Users/"+login+".yaml", out, 0666)
 383 }
 384
 385 func (s *Server) UpdateUser(login, newLogin, name, password string, access []byte) error {
 386         s.mux.Lock()
 387         defer s.mux.Unlock()
 388
 389         // update renames the user login
 390         if login != newLogin {
 391                 err := os.Rename(s.ConfigDir+"Users/"+login+".yaml", s.ConfigDir+"Users/"+newLogin+".yaml")
 392                 if err != nil {
 393                         return err
 394                 }
 395                 s.Accounts[newLogin] = s.Accounts[login]
 396                 delete(s.Accounts, login)
 397         }
 398
 399         account := s.Accounts[newLogin]
 400         account.Access = &access
 401         account.Name = name
 402         account.Password = password
 403
 404         out, err := yaml.Marshal(&account)
 405         if err != nil {
 406                 return err
 407         }
 408         if err := os.WriteFile(s.ConfigDir+"Users/"+newLogin+".yaml", out, 0666); err != nil {
 409                 return err
 410         }
 411
 412         return nil
 413 }
 414
 415 // DeleteUser deletes the user account
 416 func (s *Server) DeleteUser(login string) error {
 417         s.mux.Lock()
 418         defer s.mux.Unlock()
 419
 420         delete(s.Accounts, login)
 421
 422         return s.FS.Remove(s.ConfigDir + "Users/" + login + ".yaml")
 423 }
 424
 425 func (s *Server) connectedUsers() []Field {
 426         s.mux.Lock()
 427         defer s.mux.Unlock()
 428
 429         var connectedUsers []Field
 430         for _, c := range sortedClients(s.Clients) {
 431                 if !c.Agreed {
 432                         continue
 433                 }
 434                 user := User{
 435                         ID:    *c.ID,
 436                         Icon:  *c.Icon,
 437                         Flags: *c.Flags,
 438                         Name:  string(c.UserName),
 439                 }
 440                 connectedUsers = append(connectedUsers, NewField(fieldUsernameWithInfo, user.Payload()))
 441         }
 442         return connectedUsers
 443 }
 444
 445 // loadThreadedNews loads the threaded news data from disk
 446 func (s *Server) loadThreadedNews(threadedNewsPath string) error {
 447         fh, err := os.Open(threadedNewsPath)
 448         if err != nil {
 449                 return err
 450         }
 451         decoder := yaml.NewDecoder(fh)
 452
 453         return decoder.Decode(s.ThreadedNews)
 454 }
 455
 456 // loadAccounts loads account data from disk
 457 func (s *Server) loadAccounts(userDir string) error {
 458         matches, err := filepath.Glob(path.Join(userDir, "*.yaml"))
 459         if err != nil {
 460                 return err
 461         }
 462
 463         if len(matches) == 0 {
 464                 return errors.New("no user accounts found in " + userDir)
 465         }
 466
 467         for _, file := range matches {
 468                 fh, err := s.FS.Open(file)
 469                 if err != nil {
 470                         return err
 471                 }
 472
 473                 account := Account{}
 474                 decoder := yaml.NewDecoder(fh)
 475                 if err := decoder.Decode(&account); err != nil {
 476                         return err
 477                 }
 478
 479                 s.Accounts[account.Login] = &account
 480         }
 481         return nil
 482 }
 483
 484 func (s *Server) loadConfig(path string) error {
 485         fh, err := s.FS.Open(path)
 486         if err != nil {
 487                 return err
 488         }
 489
 490         decoder := yaml.NewDecoder(fh)
 491         err = decoder.Decode(s.Config)
 492         if err != nil {
 493                 return err
 494         }
 495
 496         validate := validator.New()
 497         err = validate.Struct(s.Config)
 498         if err != nil {
 499                 return err
 500         }
 501         return nil
 502 }
 503
 504 const (
 505         minTransactionLen = 22 // minimum length of any transaction
 506 )
 507
 508 // dontPanic recovers and logs panics instead of crashing
 509 // TODO: remove this after known issues are fixed
 510 func dontPanic(logger *zap.SugaredLogger) {
 511         if r := recover(); r != nil {
 512                 fmt.Println("stacktrace from panic: \n" + string(debug.Stack()))
 513                 logger.Errorw("PANIC", "err", r, "trace", string(debug.Stack()))
 514         }
 515 }
 516
 517 // handleNewConnection takes a new net.Conn and performs the initial login sequence
 518 func (s *Server) handleNewConnection(ctx context.Context, conn net.Conn, remoteAddr string) error {
 519         defer dontPanic(s.Logger)
 520
 521         if err := Handshake(conn); err != nil {
 522                 return err
 523         }
 524
 525         buf := make([]byte, 1024)
 526         // TODO: fix potential short read with io.ReadFull
 527         readLen, err := conn.Read(buf)
 528         if readLen < minTransactionLen {
 529                 return err
 530         }
 531         if err != nil {
 532                 return err
 533         }
 534
 535         clientLogin, _, err := ReadTransaction(buf[:readLen])
 536         if err != nil {
 537                 return err
 538         }
 539
 540         c := s.NewClientConn(conn, remoteAddr)
 541         defer c.Disconnect()
 542
 543         encodedLogin := clientLogin.GetField(fieldUserLogin).Data
 544         encodedPassword := clientLogin.GetField(fieldUserPassword).Data
 545         *c.Version = clientLogin.GetField(fieldVersion).Data
 546
 547         var login string
 548         for _, char := range encodedLogin {
 549                 login += string(rune(255 - uint(char)))
 550         }
 551         if login == "" {
 552                 login = GuestAccount
 553         }
 554
 555         // If authentication fails, send error reply and close connection
 556         if !c.Authenticate(login, encodedPassword) {
 557                 t := c.NewErrReply(clientLogin, "Incorrect login.")
 558                 b, err := t.MarshalBinary()
 559                 if err != nil {
 560                         return err
 561                 }
 562                 if _, err := conn.Write(b); err != nil {
 563                         return err
 564                 }
 565                 return fmt.Errorf("incorrect login")
 566         }
 567
 568         if clientLogin.GetField(fieldUserName).Data != nil {
 569                 c.UserName = clientLogin.GetField(fieldUserName).Data
 570         }
 571
 572         if clientLogin.GetField(fieldUserIconID).Data != nil {
 573                 *c.Icon = clientLogin.GetField(fieldUserIconID).Data
 574         }
 575
 576         c.Account = c.Server.Accounts[login]
 577
 578         if c.Authorize(accessDisconUser) {
 579                 *c.Flags = []byte{0, 2}
 580         }
 581
 582         s.Logger.Infow("Client connection received", "login", login, "version", *c.Version, "RemoteAddr", remoteAddr)
 583
 584         s.outbox <- c.NewReply(clientLogin,
 585                 NewField(fieldVersion, []byte{0x00, 0xbe}),
 586                 NewField(fieldCommunityBannerID, []byte{0x00, 0x01}),
 587                 NewField(fieldServerName, []byte(s.Config.Name)),
 588         )
 589
 590         // Send user access privs so client UI knows how to behave
 591         c.Server.outbox <- *NewTransaction(tranUserAccess, c.ID, NewField(fieldUserAccess, *c.Account.Access))
 592
 593         // Show agreement to client
 594         c.Server.outbox <- *NewTransaction(tranShowAgreement, c.ID, NewField(fieldData, s.Agreement))
 595
 596         // Used simplified hotline v1.2.3 login flow for clients that do not send login info in tranAgreed
 597         if *c.Version == nil || bytes.Equal(*c.Version, nostalgiaVersion) {
 598                 c.Agreed = true
 599
 600                 c.notifyOthers(
 601                         *NewTransaction(
 602                                 tranNotifyChangeUser, nil,
 603                                 NewField(fieldUserName, c.UserName),
 604                                 NewField(fieldUserID, *c.ID),
 605                                 NewField(fieldUserIconID, *c.Icon),
 606                                 NewField(fieldUserFlags, *c.Flags),
 607                         ),
 608                 )
 609         }
 610
 611         c.Server.Stats.LoginCount += 1
 612
 613         const readBuffSize = 1024000 // 1KB - TODO: what should this be?
 614         tranBuff := make([]byte, 0)
 615         tReadlen := 0
 616         // Infinite loop where take action on incoming client requests until the connection is closed
 617         for {
 618                 buf = make([]byte, readBuffSize)
 619                 tranBuff = tranBuff[tReadlen:]
 620
 621                 readLen, err := c.Connection.Read(buf)
 622                 if err != nil {
 623                         return err
 624                 }
 625                 tranBuff = append(tranBuff, buf[:readLen]...)
 626
 627                 // We may have read multiple requests worth of bytes from Connection.Read.  readTransactions splits them
 628                 // into a slice of transactions
 629                 var transactions []Transaction
 630                 if transactions, tReadlen, err = readTransactions(tranBuff); err != nil {
 631                         c.Server.Logger.Errorw("Error handling transaction", "err", err)
 632                 }
 633
 634                 // iterate over all the transactions that were parsed from the byte slice and handle them
 635                 for _, t := range transactions {
 636                         if err := c.handleTransaction(&t); err != nil {
 637                                 c.Server.Logger.Errorw("Error handling transaction", "err", err)
 638                         }
 639                 }
 640         }
 641 }
 642
 643 // NewTransactionRef generates a random ID for the file transfer.  The Hotline client includes this ID
 644 // in the transfer request payload, and the file transfer server will use it to map the request
 645 // to a transfer
 646 func (s *Server) NewTransactionRef() []byte {
 647         transactionRef := make([]byte, 4)
 648         rand.Read(transactionRef)
 649
 650         return transactionRef
 651 }
 652
 653 func (s *Server) NewPrivateChat(cc *ClientConn) []byte {
 654         s.mux.Lock()
 655         defer s.mux.Unlock()
 656
 657         randID := make([]byte, 4)
 658         rand.Read(randID)
 659         data := binary.BigEndian.Uint32(randID[:])
 660
 661         s.PrivateChats[data] = &PrivateChat{
 662                 Subject:    "",
 663                 ClientConn: make(map[uint16]*ClientConn),
 664         }
 665         s.PrivateChats[data].ClientConn[cc.uint16ID()] = cc
 666
 667         return randID
 668 }
 669
 670 const dlFldrActionSendFile = 1
 671 const dlFldrActionResumeFile = 2
 672 const dlFldrActionNextFile = 3
 673
 674 // handleFileTransfer receives a client net.Conn from the file transfer server, performs the requested transfer type, then closes the connection
 675 func (s *Server) handleFileTransfer(ctx context.Context, rwc io.ReadWriter) error {
 676         defer dontPanic(s.Logger)
 677
 678         txBuf := make([]byte, 16)
 679         if _, err := io.ReadFull(rwc, txBuf); err != nil {
 680                 return err
 681         }
 682
 683         var t transfer
 684         if _, err := t.Write(txBuf); err != nil {
 685                 return err
 686         }
 687
 688         transferRefNum := binary.BigEndian.Uint32(t.ReferenceNumber[:])
 689         defer func() {
 690                 s.mux.Lock()
 691                 delete(s.FileTransfers, transferRefNum)
 692                 s.mux.Unlock()
 693         }()
 694
 695         s.mux.Lock()
 696         fileTransfer, ok := s.FileTransfers[transferRefNum]
 697         s.mux.Unlock()
 698         if !ok {
 699                 return errors.New("invalid transaction ID")
 700         }
 701
 702         rLogger := s.Logger.With(
 703                 "remoteAddr", ctx.Value(contextKeyReq).(requestCtx).remoteAddr,
 704                 "xferID", transferRefNum,
 705         )
 706
 707         switch fileTransfer.Type {
 708         case FileDownload:
 709                 s.Stats.DownloadCounter += 1
 710
 711                 fullFilePath, err := readPath(s.Config.FileRoot, fileTransfer.FilePath, fileTransfer.FileName)
 712                 if err != nil {
 713                         return err
 714                 }
 715
 716                 var dataOffset int64
 717                 if fileTransfer.fileResumeData != nil {
 718                         dataOffset = int64(binary.BigEndian.Uint32(fileTransfer.fileResumeData.ForkInfoList[0].DataSize[:]))
 719                 }
 720
 721                 fw, err := newFileWrapper(s.FS, fullFilePath, 0)
 722                 if err != nil {
 723                         return err
 724                 }
 725
 726                 rLogger.Infow("File download started", "filePath", fullFilePath, "transactionRef", fileTransfer.ReferenceNumber)
 727
 728                 wr := bufio.NewWriterSize(rwc, 1460)
 729
 730                 // if file transfer options are included, that means this is a "quick preview" request from a 1.5+ client
 731                 if fileTransfer.options == nil {
 732                         // Start by sending flat file object to client
 733                         if _, err := wr.Write(fw.ffo.BinaryMarshal()); err != nil {
 734                                 return err
 735                         }
 736                 }
 737
 738                 file, err := fw.dataForkReader()
 739                 if err != nil {
 740                         return err
 741                 }
 742
 743                 if err := sendFile(wr, file, int(dataOffset)); err != nil {
 744                         return err
 745                 }
 746
 747                 if err := wr.Flush(); err != nil {
 748                         return err
 749                 }
 750
 751                 // if the client requested to resume transfer, do not send the resource fork, or it will be appended into the fileWrapper data
 752                 if fileTransfer.fileResumeData == nil {
 753                         err = binary.Write(wr, binary.BigEndian, fw.rsrcForkHeader())
 754                         if err != nil {
 755                                 return err
 756                         }
 757                         if err := wr.Flush(); err != nil {
 758                                 return err
 759                         }
 760                 }
 761
 762                 rFile, err := fw.rsrcForkFile()
 763                 if err != nil {
 764                         return nil
 765                 }
 766
 767                 err = sendFile(wr, rFile, int(dataOffset))
 768
 769                 if err := wr.Flush(); err != nil {
 770                         return err
 771                 }
 772
 773         case FileUpload:
 774                 s.Stats.UploadCounter += 1
 775
 776                 destinationFile, err := readPath(s.Config.FileRoot, fileTransfer.FilePath, fileTransfer.FileName)
 777                 if err != nil {
 778                         return err
 779                 }
 780
 781                 var file *os.File
 782
 783                 // A file upload has three possible cases:
 784                 // 1) Upload a new file
 785                 // 2) Resume a partially transferred file
 786                 // 3) Replace a fully uploaded file
 787                 //  We have to infer which case applies by inspecting what is already on the filesystem
 788
 789                 // 1) Check for existing file:
 790                 _, err = os.Stat(destinationFile)
 791                 if err == nil {
 792                         // If found, that means this upload is intended to replace the file
 793                         if err = os.Remove(destinationFile); err != nil {
 794                                 return err
 795                         }
 796                         file, err = os.Create(destinationFile + incompleteFileSuffix)
 797                 }
 798                 if errors.Is(err, fs.ErrNotExist) {
 799                         // If not found, open or create a new .incomplete file
 800                         file, err = os.OpenFile(destinationFile+incompleteFileSuffix, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0644)
 801                         if err != nil {
 802                                 return err
 803                         }
 804                 }
 805
 806                 f, err := newFileWrapper(s.FS, destinationFile, 0)
 807                 if err != nil {
 808                         return err
 809                 }
 810
 811                 defer func() { _ = file.Close() }()
 812
 813                 s.Logger.Infow("File upload started", "transactionRef", fileTransfer.ReferenceNumber, "dstFile", destinationFile)
 814
 815                 rForkWriter := io.Discard
 816                 iForkWriter := io.Discard
 817                 if s.Config.PreserveResourceForks {
 818                         rForkWriter, err = f.rsrcForkWriter()
 819                         if err != nil {
 820                                 return err
 821                         }
 822
 823                         iForkWriter, err = f.infoForkWriter()
 824                         if err != nil {
 825                                 return err
 826                         }
 827                 }
 828
 829                 if err := receiveFile(rwc, file, rForkWriter, iForkWriter); err != nil {
 830                         return err
 831                 }
 832
 833                 if err := s.FS.Rename(destinationFile+".incomplete", destinationFile); err != nil {
 834                         return err
 835                 }
 836
 837                 s.Logger.Infow("File upload complete", "transactionRef", fileTransfer.ReferenceNumber, "dstFile", destinationFile)
 838         case FolderDownload:
 839                 // Folder Download flow:
 840                 // 1. Get filePath from the transfer
 841                 // 2. Iterate over files
 842                 // 3. For each fileWrapper:
 843                 //       Send fileWrapper header to client
 844                 // The client can reply in 3 ways:
 845                 //
 846                 // 1. If type is an odd number (unknown type?), or fileWrapper download for the current fileWrapper is completed:
 847                 //              client sends []byte{0x00, 0x03} to tell the server to continue to the next fileWrapper
 848                 //
 849                 // 2. If download of a fileWrapper is to be resumed:
 850                 //              client sends:
 851                 //                      []byte{0x00, 0x02} // download folder action
 852                 //                      [2]byte // Resume data size
 853                 //                      []byte fileWrapper resume data (see myField_FileResumeData)
 854                 //
 855                 // 3. Otherwise, download of the fileWrapper is requested and client sends []byte{0x00, 0x01}
 856                 //
 857                 // When download is requested (case 2 or 3), server replies with:
 858                 //                      [4]byte - fileWrapper size
 859                 //                      []byte  - Flattened File Object
 860                 //
 861                 // After every fileWrapper download, client could request next fileWrapper with:
 862                 //                      []byte{0x00, 0x03}
 863                 //
 864                 // This notifies the server to send the next item header
 865
 866                 fullFilePath, err := readPath(s.Config.FileRoot, fileTransfer.FilePath, fileTransfer.FileName)
 867                 if err != nil {
 868                         return err
 869                 }
 870
 871                 basePathLen := len(fullFilePath)
 872
 873                 s.Logger.Infow("Start folder download", "path", fullFilePath, "ReferenceNumber", fileTransfer.ReferenceNumber)
 874
 875                 nextAction := make([]byte, 2)
 876                 if _, err := io.ReadFull(rwc, nextAction); err != nil {
 877                         return err
 878                 }
 879
 880                 i := 0
 881                 err = filepath.Walk(fullFilePath+"/", func(path string, info os.FileInfo, err error) error {
 882                         s.Stats.DownloadCounter += 1
 883                         i += 1
 884
 885                         if err != nil {
 886                                 return err
 887                         }
 888
 889                         // skip dot files
 890                         if strings.HasPrefix(info.Name(), ".") {
 891                                 return nil
 892                         }
 893
 894                         hlFile, err := newFileWrapper(s.FS, path, 0)
 895                         if err != nil {
 896                                 return err
 897                         }
 898
 899                         subPath := path[basePathLen+1:]
 900                         s.Logger.Infow("Sending fileheader", "i", i, "path", path, "fullFilePath", fullFilePath, "subPath", subPath, "IsDir", info.IsDir())
 901
 902                         if i == 1 {
 903                                 return nil
 904                         }
 905
 906                         fileHeader := NewFileHeader(subPath, info.IsDir())
 907
 908                         // Send the fileWrapper header to client
 909                         if _, err := rwc.Write(fileHeader.Payload()); err != nil {
 910                                 s.Logger.Errorf("error sending file header: %v", err)
 911                                 return err
 912                         }
 913
 914                         // Read the client's Next Action request
 915                         if _, err := io.ReadFull(rwc, nextAction); err != nil {
 916                                 return err
 917                         }
 918
 919                         s.Logger.Infow("Client folder download action", "action", fmt.Sprintf("%X", nextAction[0:2]))
 920
 921                         var dataOffset int64
 922
 923                         switch nextAction[1] {
 924                         case dlFldrActionResumeFile:
 925                                 // get size of resumeData
 926                                 resumeDataByteLen := make([]byte, 2)
 927                                 if _, err := io.ReadFull(rwc, resumeDataByteLen); err != nil {
 928                                         return err
 929                                 }
 930
 931                                 resumeDataLen := binary.BigEndian.Uint16(resumeDataByteLen)
 932                                 resumeDataBytes := make([]byte, resumeDataLen)
 933                                 if _, err := io.ReadFull(rwc, resumeDataBytes); err != nil {
 934                                         return err
 935                                 }
 936
 937                                 var frd FileResumeData
 938                                 if err := frd.UnmarshalBinary(resumeDataBytes); err != nil {
 939                                         return err
 940                                 }
 941                                 dataOffset = int64(binary.BigEndian.Uint32(frd.ForkInfoList[0].DataSize[:]))
 942                         case dlFldrActionNextFile:
 943                                 // client asked to skip this file
 944                                 return nil
 945                         }
 946
 947                         if info.IsDir() {
 948                                 return nil
 949                         }
 950
 951                         s.Logger.Infow("File download started",
 952                                 "fileName", info.Name(),
 953                                 "transactionRef", fileTransfer.ReferenceNumber,
 954                                 "TransferSize", fmt.Sprintf("%x", hlFile.ffo.TransferSize(dataOffset)),
 955                         )
 956
 957                         // Send file size to client
 958                         if _, err := rwc.Write(hlFile.ffo.TransferSize(dataOffset)); err != nil {
 959                                 s.Logger.Error(err)
 960                                 return err
 961                         }
 962
 963                         // Send ffo bytes to client
 964                         if _, err := rwc.Write(hlFile.ffo.BinaryMarshal()); err != nil {
 965                                 s.Logger.Error(err)
 966                                 return err
 967                         }
 968
 969                         file, err := s.FS.Open(path)
 970                         if err != nil {
 971                                 return err
 972                         }
 973
 974                         // wr := bufio.NewWriterSize(rwc, 1460)
 975                         err = sendFile(rwc, file, int(dataOffset))
 976                         if err != nil {
 977                                 return err
 978                         }
 979
 980                         if nextAction[1] != 2 && hlFile.ffo.FlatFileHeader.ForkCount[1] == 3 {
 981                                 err = binary.Write(rwc, binary.BigEndian, hlFile.rsrcForkHeader())
 982                                 if err != nil {
 983                                         return err
 984                                 }
 985
 986                                 rFile, err := hlFile.rsrcForkFile()
 987                                 if err != nil {
 988                                         return err
 989                                 }
 990
 991                                 err = sendFile(rwc, rFile, int(dataOffset))
 992                                 if err != nil {
 993                                         return err
 994                                 }
 995                         }
 996
 997                         // Read the client's Next Action request.  This is always 3, I think?
 998                         if _, err := io.ReadFull(rwc, nextAction); err != nil {
 999                                 return err
1000                         }
1001
1002                         return nil
1003                 })
1004
1005         case FolderUpload:
1006                 dstPath, err := readPath(s.Config.FileRoot, fileTransfer.FilePath, fileTransfer.FileName)
1007                 if err != nil {
1008                         return err
1009                 }
1010
1011                 s.Logger.Infow(
1012                         "Folder upload started",
1013                         "transactionRef", fileTransfer.ReferenceNumber,
1014                         "dstPath", dstPath,
1015                         "TransferSize", fmt.Sprintf("%x", fileTransfer.TransferSize),
1016                         "FolderItemCount", fileTransfer.FolderItemCount,
1017                 )
1018
1019                 // Check if the target folder exists.  If not, create it.
1020                 if _, err := s.FS.Stat(dstPath); os.IsNotExist(err) {
1021                         if err := s.FS.Mkdir(dstPath, 0777); err != nil {
1022                                 return err
1023                         }
1024                 }
1025
1026                 // Begin the folder upload flow by sending the "next file action" to client
1027                 if _, err := rwc.Write([]byte{0, dlFldrActionNextFile}); err != nil {
1028                         return err
1029                 }
1030
1031                 fileSize := make([]byte, 4)
1032
1033                 for i := 0; i < fileTransfer.ItemCount(); i++ {
1034                         s.Stats.UploadCounter += 1
1035
1036                         var fu folderUpload
1037                         if _, err := io.ReadFull(rwc, fu.DataSize[:]); err != nil {
1038                                 return err
1039                         }
1040                         if _, err := io.ReadFull(rwc, fu.IsFolder[:]); err != nil {
1041                                 return err
1042                         }
1043                         if _, err := io.ReadFull(rwc, fu.PathItemCount[:]); err != nil {
1044                                 return err
1045                         }
1046
1047                         fu.FileNamePath = make([]byte, binary.BigEndian.Uint16(fu.DataSize[:])-4) // -4 to subtract the path separator bytes
1048
1049                         if _, err := io.ReadFull(rwc, fu.FileNamePath); err != nil {
1050                                 return err
1051                         }
1052
1053                         s.Logger.Infow(
1054                                 "Folder upload continued",
1055                                 "transactionRef", fmt.Sprintf("%x", fileTransfer.ReferenceNumber),
1056                                 "FormattedPath", fu.FormattedPath(),
1057                                 "IsFolder", fmt.Sprintf("%x", fu.IsFolder),
1058                                 "PathItemCount", binary.BigEndian.Uint16(fu.PathItemCount[:]),
1059                         )
1060
1061                         if fu.IsFolder == [2]byte{0, 1} {
1062                                 if _, err := os.Stat(dstPath + "/" + fu.FormattedPath()); os.IsNotExist(err) {
1063                                         if err := os.Mkdir(dstPath+"/"+fu.FormattedPath(), 0777); err != nil {
1064                                                 return err
1065                                         }
1066                                 }
1067
1068                                 // Tell client to send next file
1069                                 if _, err := rwc.Write([]byte{0, dlFldrActionNextFile}); err != nil {
1070                                         return err
1071                                 }
1072                         } else {
1073                                 nextAction := dlFldrActionSendFile
1074
1075                                 // Check if we have the full file already.  If so, send dlFldrAction_NextFile to client to skip.
1076                                 _, err = os.Stat(dstPath + "/" + fu.FormattedPath())
1077                                 if err != nil && !errors.Is(err, fs.ErrNotExist) {
1078                                         return err
1079                                 }
1080                                 if err == nil {
1081                                         nextAction = dlFldrActionNextFile
1082                                 }
1083
1084                                 //  Check if we have a partial file already.  If so, send dlFldrAction_ResumeFile to client to resume upload.
1085                                 incompleteFile, err := os.Stat(dstPath + "/" + fu.FormattedPath() + incompleteFileSuffix)
1086                                 if err != nil && !errors.Is(err, fs.ErrNotExist) {
1087                                         return err
1088                                 }
1089                                 if err == nil {
1090                                         nextAction = dlFldrActionResumeFile
1091                                 }
1092
1093                                 if _, err := rwc.Write([]byte{0, uint8(nextAction)}); err != nil {
1094                                         return err
1095                                 }
1096
1097                                 switch nextAction {
1098                                 case dlFldrActionNextFile:
1099                                         continue
1100                                 case dlFldrActionResumeFile:
1101                                         offset := make([]byte, 4)
1102                                         binary.BigEndian.PutUint32(offset, uint32(incompleteFile.Size()))
1103
1104                                         file, err := os.OpenFile(dstPath+"/"+fu.FormattedPath()+incompleteFileSuffix, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
1105                                         if err != nil {
1106                                                 return err
1107                                         }
1108
1109                                         fileResumeData := NewFileResumeData([]ForkInfoList{*NewForkInfoList(offset)})
1110
1111                                         b, _ := fileResumeData.BinaryMarshal()
1112
1113                                         bs := make([]byte, 2)
1114                                         binary.BigEndian.PutUint16(bs, uint16(len(b)))
1115
1116                                         if _, err := rwc.Write(append(bs, b...)); err != nil {
1117                                                 return err
1118                                         }
1119
1120                                         if _, err := io.ReadFull(rwc, fileSize); err != nil {
1121                                                 return err
1122                                         }
1123
1124                                         if err := receiveFile(rwc, file, ioutil.Discard, ioutil.Discard); err != nil {
1125                                                 s.Logger.Error(err)
1126                                         }
1127
1128                                         err = os.Rename(dstPath+"/"+fu.FormattedPath()+".incomplete", dstPath+"/"+fu.FormattedPath())
1129                                         if err != nil {
1130                                                 return err
1131                                         }
1132
1133                                 case dlFldrActionSendFile:
1134                                         if _, err := io.ReadFull(rwc, fileSize); err != nil {
1135                                                 return err
1136                                         }
1137
1138                                         filePath := dstPath + "/" + fu.FormattedPath()
1139
1140                                         hlFile, err := newFileWrapper(s.FS, filePath, 0)
1141                                         if err != nil {
1142                                                 return err
1143                                         }
1144
1145                                         s.Logger.Infow("Starting file transfer", "path", filePath, "fileNum", i+1, "fileSize", binary.BigEndian.Uint32(fileSize))
1146
1147                                         incWriter, err := hlFile.incFileWriter()
1148                                         if err != nil {
1149                                                 return err
1150                                         }
1151
1152                                         rForkWriter := io.Discard
1153                                         iForkWriter := io.Discard
1154                                         if s.Config.PreserveResourceForks {
1155                                                 iForkWriter, err = hlFile.infoForkWriter()
1156                                                 if err != nil {
1157                                                         return err
1158                                                 }
1159
1160                                                 rForkWriter, err = hlFile.rsrcForkWriter()
1161                                                 if err != nil {
1162                                                         return err
1163                                                 }
1164                                         }
1165                                         if err := receiveFile(rwc, incWriter, rForkWriter, iForkWriter); err != nil {
1166                                                 return err
1167                                         }
1168                                         // _ = newFile.Close()
1169                                         if err := os.Rename(filePath+".incomplete", filePath); err != nil {
1170                                                 return err
1171                                         }
1172                                 }
1173
1174                                 // Tell client to send next fileWrapper
1175                                 if _, err := rwc.Write([]byte{0, dlFldrActionNextFile}); err != nil {
1176                                         return err
1177                                 }
1178                         }
1179                 }
1180                 s.Logger.Infof("Folder upload complete")
1181         }
1182
1183         return nil
1184 }