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

   1 package hotline
   2
   3 import (
   4         "bytes"
   5         "context"
   6         "encoding/binary"
   7         "errors"
   8         "fmt"
   9         "go.uber.org/zap"
  10         "io"
  11         "io/ioutil"
  12         "log"
  13         "math/big"
  14         "math/rand"
  15         "net"
  16         "os"
  17         "path"
  18         "path/filepath"
  19         "runtime/debug"
  20         "sort"
  21         "strings"
  22         "sync"
  23         "time"
  24
  25         "golang.org/x/crypto/bcrypt"
  26         "gopkg.in/yaml.v2"
  27 )
  28
  29 const (
  30         userIdleSeconds        = 300 // time in seconds before an inactive user is marked idle
  31         idleCheckInterval      = 10  // time in seconds to check for idle users
  32         trackerUpdateFrequency = 300 // time in seconds between tracker re-registration
  33 )
  34
  35 type Server struct {
  36         Port          int
  37         Accounts      map[string]*Account
  38         Agreement     []byte
  39         Clients       map[uint16]*ClientConn
  40         FlatNews      []byte
  41         ThreadedNews  *ThreadedNews
  42         FileTransfers map[uint32]*FileTransfer
  43         Config        *Config
  44         ConfigDir     string
  45         Logger        *zap.SugaredLogger
  46         PrivateChats  map[uint32]*PrivateChat
  47         NextGuestID   *uint16
  48         TrackerPassID []byte
  49         Stats         *Stats
  50
  51         APIListener  net.Listener
  52         FileListener net.Listener
  53
  54         newsReader io.Reader
  55         newsWriter io.WriteCloser
  56
  57         outbox chan Transaction
  58
  59         mux         sync.Mutex
  60         flatNewsMux sync.Mutex
  61 }
  62
  63 type PrivateChat struct {
  64         Subject    string
  65         ClientConn map[uint16]*ClientConn
  66 }
  67
  68 func (s *Server) ListenAndServe(ctx context.Context, cancelRoot context.CancelFunc) error {
  69         s.Logger.Infow("Hotline server started", "version", VERSION)
  70         var wg sync.WaitGroup
  71
  72         wg.Add(1)
  73         go func() { s.Logger.Fatal(s.Serve(ctx, cancelRoot, s.APIListener)) }()
  74
  75         wg.Add(1)
  76         go func() { s.Logger.Fatal(s.ServeFileTransfers(s.FileListener)) }()
  77
  78         wg.Wait()
  79
  80         return nil
  81 }
  82
  83 func (s *Server) APIPort() int {
  84         return s.APIListener.Addr().(*net.TCPAddr).Port
  85 }
  86
  87 func (s *Server) ServeFileTransfers(ln net.Listener) error {
  88         s.Logger.Infow("Hotline file transfer server started", "Addr", fmt.Sprintf(":%v", s.Port+1))
  89
  90         for {
  91                 conn, err := ln.Accept()
  92                 if err != nil {
  93                         return err
  94                 }
  95
  96                 go func() {
  97                         if err := s.TransferFile(conn); err != nil {
  98                                 s.Logger.Errorw("file transfer error", "reason", err)
  99                         }
 100                 }()
 101         }
 102 }
 103
 104 func (s *Server) sendTransaction(t Transaction) error {
 105         requestNum := binary.BigEndian.Uint16(t.Type)
 106         clientID, err := byteToInt(*t.clientID)
 107         if err != nil {
 108                 return err
 109         }
 110
 111         s.mux.Lock()
 112         client := s.Clients[uint16(clientID)]
 113         s.mux.Unlock()
 114         if client == nil {
 115                 return errors.New("invalid client")
 116         }
 117         userName := string(client.UserName)
 118         login := client.Account.Login
 119
 120         handler := TransactionHandlers[requestNum]
 121
 122         b, err := t.MarshalBinary()
 123         if err != nil {
 124                 return err
 125         }
 126         var n int
 127         if n, err = client.Connection.Write(b); err != nil {
 128                 return err
 129         }
 130         s.Logger.Debugw("Sent Transaction",
 131                 "name", userName,
 132                 "login", login,
 133                 "IsReply", t.IsReply,
 134                 "type", handler.Name,
 135                 "sentBytes", n,
 136                 "remoteAddr", client.Connection.RemoteAddr(),
 137         )
 138         return nil
 139 }
 140
 141 func (s *Server) Serve(ctx context.Context, cancelRoot context.CancelFunc, ln net.Listener) error {
 142         s.Logger.Infow("Hotline server started", "Addr", fmt.Sprintf(":%v", s.Port))
 143
 144         for {
 145                 conn, err := ln.Accept()
 146                 if err != nil {
 147                         s.Logger.Errorw("error accepting connection", "err", err)
 148                 }
 149
 150                 go func() {
 151                         for {
 152                                 t := <-s.outbox
 153                                 go func() {
 154                                         if err := s.sendTransaction(t); err != nil {
 155                                                 s.Logger.Errorw("error sending transaction", "err", err)
 156                                         }
 157                                 }()
 158                         }
 159                 }()
 160                 go func() {
 161                         if err := s.handleNewConnection(conn); err != nil {
 162                                 if err == io.EOF {
 163                                         s.Logger.Infow("Client disconnected", "RemoteAddr", conn.RemoteAddr())
 164                                 } else {
 165                                         s.Logger.Errorw("error serving request", "RemoteAddr", conn.RemoteAddr(), "err", err)
 166                                 }
 167                         }
 168                 }()
 169         }
 170 }
 171
 172 const (
 173         agreementFile    = "Agreement.txt"
 174 )
 175
 176 // NewServer constructs a new Server from a config dir
 177 func NewServer(configDir, netInterface string, netPort int, logger *zap.SugaredLogger) (*Server, error) {
 178         server := Server{
 179                 Port:          netPort,
 180                 Accounts:      make(map[string]*Account),
 181                 Config:        new(Config),
 182                 Clients:       make(map[uint16]*ClientConn),
 183                 FileTransfers: make(map[uint32]*FileTransfer),
 184                 PrivateChats:  make(map[uint32]*PrivateChat),
 185                 ConfigDir:     configDir,
 186                 Logger:        logger,
 187                 NextGuestID:   new(uint16),
 188                 outbox:        make(chan Transaction),
 189                 Stats:         &Stats{StartTime: time.Now()},
 190                 ThreadedNews:  &ThreadedNews{},
 191                 TrackerPassID: make([]byte, 4),
 192         }
 193
 194         ln, err := net.Listen("tcp", fmt.Sprintf("%s:%v", netInterface, netPort))
 195         if err != nil {
 196                 return nil, err
 197         }
 198         server.APIListener = ln
 199
 200         if netPort != 0 {
 201                 netPort += 1
 202         }
 203
 204         ln2, err := net.Listen("tcp", fmt.Sprintf("%s:%v", netInterface, netPort))
 205         server.FileListener = ln2
 206         if err != nil {
 207                 return nil, err
 208         }
 209
 210         // generate a new random passID for tracker registration
 211         if _, err := rand.Read(server.TrackerPassID); err != nil {
 212                 return nil, err
 213         }
 214
 215         server.Logger.Debugw("Loading Agreement", "path", configDir+agreementFile)
 216         if server.Agreement, err = os.ReadFile(configDir + agreementFile); err != nil {
 217                 return nil, err
 218         }
 219
 220         if server.FlatNews, err = os.ReadFile(configDir + "MessageBoard.txt"); err != nil {
 221                 return nil, err
 222         }
 223
 224         if err := server.loadThreadedNews(configDir + "ThreadedNews.yaml"); err != nil {
 225                 return nil, err
 226         }
 227
 228         if err := server.loadConfig(configDir + "config.yaml"); err != nil {
 229                 return nil, err
 230         }
 231
 232         if err := server.loadAccounts(configDir + "Users/"); err != nil {
 233                 return nil, err
 234         }
 235
 236         server.Config.FileRoot = configDir + "Files/"
 237
 238         *server.NextGuestID = 1
 239
 240         if server.Config.EnableTrackerRegistration {
 241                 go func() {
 242                         for {
 243                                 tr := TrackerRegistration{
 244                                         Port:        []byte{0x15, 0x7c},
 245                                         UserCount:   server.userCount(),
 246                                         PassID:      server.TrackerPassID,
 247                                         Name:        server.Config.Name,
 248                                         Description: server.Config.Description,
 249                                 }
 250                                 for _, t := range server.Config.Trackers {
 251                                         server.Logger.Infof("Registering with tracker %v", t)
 252
 253                                         if err := register(t, tr); err != nil {
 254                                                 server.Logger.Errorw("unable to register with tracker %v", "error", err)
 255                                         }
 256                                 }
 257
 258                                 time.Sleep(trackerUpdateFrequency * time.Second)
 259                         }
 260                 }()
 261         }
 262
 263         // Start Client Keepalive go routine
 264         go server.keepaliveHandler()
 265
 266         return &server, nil
 267 }
 268
 269 func (s *Server) userCount() int {
 270         s.mux.Lock()
 271         defer s.mux.Unlock()
 272
 273         return len(s.Clients)
 274 }
 275
 276 func (s *Server) keepaliveHandler() {
 277         for {
 278                 time.Sleep(idleCheckInterval * time.Second)
 279                 s.mux.Lock()
 280
 281                 for _, c := range s.Clients {
 282                         *c.IdleTime += idleCheckInterval
 283                         if *c.IdleTime > userIdleSeconds && !c.Idle {
 284                                 c.Idle = true
 285
 286                                 flagBitmap := big.NewInt(int64(binary.BigEndian.Uint16(*c.Flags)))
 287                                 flagBitmap.SetBit(flagBitmap, userFlagAway, 1)
 288                                 binary.BigEndian.PutUint16(*c.Flags, uint16(flagBitmap.Int64()))
 289
 290                                 c.sendAll(
 291                                         tranNotifyChangeUser,
 292                                         NewField(fieldUserID, *c.ID),
 293                                         NewField(fieldUserFlags, *c.Flags),
 294                                         NewField(fieldUserName, c.UserName),
 295                                         NewField(fieldUserIconID, *c.Icon),
 296                                 )
 297                         }
 298                 }
 299                 s.mux.Unlock()
 300         }
 301 }
 302
 303 func (s *Server) writeThreadedNews() error {
 304         s.mux.Lock()
 305         defer s.mux.Unlock()
 306
 307         out, err := yaml.Marshal(s.ThreadedNews)
 308         if err != nil {
 309                 return err
 310         }
 311         err = ioutil.WriteFile(
 312                 s.ConfigDir+"ThreadedNews.yaml",
 313                 out,
 314                 0666,
 315         )
 316         return err
 317 }
 318
 319 func (s *Server) NewClientConn(conn net.Conn) *ClientConn {
 320         s.mux.Lock()
 321         defer s.mux.Unlock()
 322
 323         clientConn := &ClientConn{
 324                 ID:         &[]byte{0, 0},
 325                 Icon:       &[]byte{0, 0},
 326                 Flags:      &[]byte{0, 0},
 327                 UserName:   []byte{},
 328                 Connection: conn,
 329                 Server:     s,
 330                 Version:    &[]byte{},
 331                 IdleTime:   new(int),
 332                 AutoReply:  &[]byte{},
 333                 Transfers:  make(map[int][]*FileTransfer),
 334         }
 335         *s.NextGuestID++
 336         ID := *s.NextGuestID
 337
 338         *clientConn.IdleTime = 0
 339
 340         binary.BigEndian.PutUint16(*clientConn.ID, ID)
 341         s.Clients[ID] = clientConn
 342
 343         return clientConn
 344 }
 345
 346 // NewUser creates a new user account entry in the server map and config file
 347 func (s *Server) NewUser(login, name, password string, access []byte) error {
 348         s.mux.Lock()
 349         defer s.mux.Unlock()
 350
 351         account := Account{
 352                 Login:    login,
 353                 Name:     name,
 354                 Password: hashAndSalt([]byte(password)),
 355                 Access:   &access,
 356         }
 357         out, err := yaml.Marshal(&account)
 358         if err != nil {
 359                 return err
 360         }
 361         s.Accounts[login] = &account
 362
 363         return ioutil.WriteFile(s.ConfigDir+"Users/"+login+".yaml", out, 0666)
 364 }
 365
 366 // DeleteUser deletes the user account
 367 func (s *Server) DeleteUser(login string) error {
 368         s.mux.Lock()
 369         defer s.mux.Unlock()
 370
 371         delete(s.Accounts, login)
 372
 373         return os.Remove(s.ConfigDir + "Users/" + login + ".yaml")
 374 }
 375
 376 func (s *Server) connectedUsers() []Field {
 377         s.mux.Lock()
 378         defer s.mux.Unlock()
 379
 380         var connectedUsers []Field
 381         for _, c := range s.Clients {
 382                 user := User{
 383                         ID:    *c.ID,
 384                         Icon:  *c.Icon,
 385                         Flags: *c.Flags,
 386                         Name:  string(c.UserName),
 387                 }
 388                 connectedUsers = append(connectedUsers, NewField(fieldUsernameWithInfo, user.Payload()))
 389         }
 390         return connectedUsers
 391 }
 392
 393 // loadThreadedNews loads the threaded news data from disk
 394 func (s *Server) loadThreadedNews(threadedNewsPath string) error {
 395         fh, err := os.Open(threadedNewsPath)
 396         if err != nil {
 397                 return err
 398         }
 399         decoder := yaml.NewDecoder(fh)
 400         decoder.SetStrict(true)
 401
 402         return decoder.Decode(s.ThreadedNews)
 403 }
 404
 405 // loadAccounts loads account data from disk
 406 func (s *Server) loadAccounts(userDir string) error {
 407         matches, err := filepath.Glob(path.Join(userDir, "*.yaml"))
 408         if err != nil {
 409                 return err
 410         }
 411
 412         if len(matches) == 0 {
 413                 return errors.New("no user accounts found in " + userDir)
 414         }
 415
 416         for _, file := range matches {
 417                 fh, err := os.Open(file)
 418                 if err != nil {
 419                         return err
 420                 }
 421
 422                 account := Account{}
 423                 decoder := yaml.NewDecoder(fh)
 424                 decoder.SetStrict(true)
 425                 if err := decoder.Decode(&account); err != nil {
 426                         return err
 427                 }
 428
 429                 s.Accounts[account.Login] = &account
 430         }
 431         return nil
 432 }
 433
 434 func (s *Server) loadConfig(path string) error {
 435         fh, err := os.Open(path)
 436         if err != nil {
 437                 return err
 438         }
 439
 440         decoder := yaml.NewDecoder(fh)
 441         decoder.SetStrict(true)
 442         err = decoder.Decode(s.Config)
 443         if err != nil {
 444                 return err
 445         }
 446         return nil
 447 }
 448
 449 const (
 450         minTransactionLen = 22 // minimum length of any transaction
 451 )
 452
 453 // handleNewConnection takes a new net.Conn and performs the initial login sequence
 454 func (s *Server) handleNewConnection(conn net.Conn) error {
 455         handshakeBuf := make([]byte, 12) // handshakes are always 12 bytes in length
 456         if _, err := conn.Read(handshakeBuf); err != nil {
 457                 return err
 458         }
 459         if err := Handshake(conn, handshakeBuf[:12]); err != nil {
 460                 return err
 461         }
 462
 463         buf := make([]byte, 1024)
 464         readLen, err := conn.Read(buf)
 465         if readLen < minTransactionLen {
 466                 return err
 467         }
 468         if err != nil {
 469                 return err
 470         }
 471
 472         clientLogin, _, err := ReadTransaction(buf[:readLen])
 473         if err != nil {
 474                 return err
 475         }
 476
 477         c := s.NewClientConn(conn)
 478         defer c.Disconnect()
 479         defer func() {
 480                 if r := recover(); r != nil {
 481                         fmt.Println("stacktrace from panic: \n" + string(debug.Stack()))
 482                         c.Server.Logger.Errorw("PANIC", "err", r, "trace", string(debug.Stack()))
 483                         c.Disconnect()
 484                 }
 485         }()
 486
 487         encodedLogin := clientLogin.GetField(fieldUserLogin).Data
 488         encodedPassword := clientLogin.GetField(fieldUserPassword).Data
 489         *c.Version = clientLogin.GetField(fieldVersion).Data
 490
 491         var login string
 492         for _, char := range encodedLogin {
 493                 login += string(rune(255 - uint(char)))
 494         }
 495         if login == "" {
 496                 login = GuestAccount
 497         }
 498
 499         // If authentication fails, send error reply and close connection
 500         if !c.Authenticate(login, encodedPassword) {
 501                 t := c.NewErrReply(clientLogin, "Incorrect login.")
 502                 b, err := t.MarshalBinary()
 503                 if err != nil {
 504                         return err
 505                 }
 506                 if _, err := conn.Write(b); err != nil {
 507                         return err
 508                 }
 509                 return fmt.Errorf("incorrect login")
 510         }
 511
 512         if clientLogin.GetField(fieldUserName).Data != nil {
 513                 c.UserName = clientLogin.GetField(fieldUserName).Data
 514         }
 515
 516         if clientLogin.GetField(fieldUserIconID).Data != nil {
 517                 *c.Icon = clientLogin.GetField(fieldUserIconID).Data
 518         }
 519
 520         c.Account = c.Server.Accounts[login]
 521
 522         if c.Authorize(accessDisconUser) {
 523                 *c.Flags = []byte{0, 2}
 524         }
 525
 526         s.Logger.Infow("Client connection received", "login", login, "version", *c.Version, "RemoteAddr", conn.RemoteAddr().String())
 527
 528         s.outbox <- c.NewReply(clientLogin,
 529                 NewField(fieldVersion, []byte{0x00, 0xbe}),
 530                 NewField(fieldCommunityBannerID, []byte{0x00, 0x01}),
 531                 NewField(fieldServerName, []byte(s.Config.Name)),
 532         )
 533
 534         // Send user access privs so client UI knows how to behave
 535         c.Server.outbox <- *NewTransaction(tranUserAccess, c.ID, NewField(fieldUserAccess, *c.Account.Access))
 536
 537         // Show agreement to client
 538         c.Server.outbox <- *NewTransaction(tranShowAgreement, c.ID, NewField(fieldData, s.Agreement))
 539
 540         if _, err := c.notifyNewUserHasJoined(); err != nil {
 541                 return err
 542         }
 543         c.Server.Stats.LoginCount += 1
 544
 545         const readBuffSize = 1024000 // 1KB - TODO: what should this be?
 546         const maxTranSize = 1024000
 547         tranBuff := make([]byte, 0)
 548         tReadlen := 0
 549         // Infinite loop where take action on incoming client requests until the connection is closed
 550         for {
 551                 buf = make([]byte, readBuffSize)
 552                 tranBuff = tranBuff[tReadlen:]
 553
 554                 readLen, err := c.Connection.Read(buf)
 555                 if err != nil {
 556                         return err
 557                 }
 558                 tranBuff = append(tranBuff, buf[:readLen]...)
 559
 560                 // We may have read multiple requests worth of bytes from Connection.Read.  readTransactions splits them
 561                 // into a slice of transactions
 562                 var transactions []Transaction
 563                 if transactions, tReadlen, err = readTransactions(tranBuff); err != nil {
 564                         c.Server.Logger.Errorw("Error handling transaction", "err", err)
 565                 }
 566
 567                 // iterate over all of the transactions that were parsed from the byte slice and handle them
 568                 for _, t := range transactions {
 569                         if err := c.handleTransaction(&t); err != nil {
 570                                 c.Server.Logger.Errorw("Error handling transaction", "err", err)
 571                         }
 572                 }
 573         }
 574 }
 575
 576 func hashAndSalt(pwd []byte) string {
 577         // Use GenerateFromPassword to hash & salt pwd.
 578         // MinCost is just an integer constant provided by the bcrypt
 579         // package along with DefaultCost & MaxCost.
 580         // The cost can be any value you want provided it isn't lower
 581         // than the MinCost (4)
 582         hash, err := bcrypt.GenerateFromPassword(pwd, bcrypt.MinCost)
 583         if err != nil {
 584                 log.Println(err)
 585         }
 586         // GenerateFromPassword returns a byte slice so we need to
 587         // convert the bytes to a string and return it
 588         return string(hash)
 589 }
 590
 591 // NewTransactionRef generates a random ID for the file transfer.  The Hotline client includes this ID
 592 // in the file transfer request payload, and the file transfer server will use it to map the request
 593 // to a transfer
 594 func (s *Server) NewTransactionRef() []byte {
 595         transactionRef := make([]byte, 4)
 596         rand.Read(transactionRef)
 597
 598         return transactionRef
 599 }
 600
 601 func (s *Server) NewPrivateChat(cc *ClientConn) []byte {
 602         s.mux.Lock()
 603         defer s.mux.Unlock()
 604
 605         randID := make([]byte, 4)
 606         rand.Read(randID)
 607         data := binary.BigEndian.Uint32(randID[:])
 608
 609         s.PrivateChats[data] = &PrivateChat{
 610                 Subject:    "",
 611                 ClientConn: make(map[uint16]*ClientConn),
 612         }
 613         s.PrivateChats[data].ClientConn[cc.uint16ID()] = cc
 614
 615         return randID
 616 }
 617
 618 const dlFldrActionSendFile = 1
 619 const dlFldrActionResumeFile = 2
 620 const dlFldrActionNextFile = 3
 621
 622 func (s *Server) TransferFile(conn net.Conn) error {
 623         defer func() { _ = conn.Close() }()
 624
 625         buf := make([]byte, 1024)
 626         if _, err := conn.Read(buf); err != nil {
 627                 return err
 628         }
 629
 630         var t transfer
 631         _, err := t.Write(buf[:16])
 632         if err != nil {
 633                 return err
 634         }
 635
 636         transferRefNum := binary.BigEndian.Uint32(t.ReferenceNumber[:])
 637         fileTransfer := s.FileTransfers[transferRefNum]
 638
 639         switch fileTransfer.Type {
 640         case FileDownload:
 641                 fullFilePath := fmt.Sprintf("%v/%v", s.Config.FileRoot+string(fileTransfer.FilePath), string(fileTransfer.FileName))
 642
 643                 ffo, err := NewFlattenedFileObject(
 644                         s.Config.FileRoot+string(fileTransfer.FilePath),
 645                         string(fileTransfer.FileName),
 646                 )
 647                 if err != nil {
 648                         return err
 649                 }
 650
 651                 s.Logger.Infow("File download started", "filePath", fullFilePath, "transactionRef", fileTransfer.ReferenceNumber, "RemoteAddr", conn.RemoteAddr().String())
 652
 653                 // Start by sending flat file object to client
 654                 if _, err := conn.Write(ffo.Payload()); err != nil {
 655                         return err
 656                 }
 657
 658                 file, err := os.Open(fullFilePath)
 659                 if err != nil {
 660                         return err
 661                 }
 662
 663                 sendBuffer := make([]byte, 1048576)
 664                 for {
 665                         var bytesRead int
 666                         if bytesRead, err = file.Read(sendBuffer); err == io.EOF {
 667                                 break
 668                         }
 669
 670                         fileTransfer.BytesSent += bytesRead
 671
 672                         delete(s.FileTransfers, transferRefNum)
 673
 674                         if _, err := conn.Write(sendBuffer[:bytesRead]); err != nil {
 675                                 return err
 676                         }
 677                 }
 678         case FileUpload:
 679                 if _, err := conn.Read(buf); err != nil {
 680                         return err
 681                 }
 682
 683                 ffo := ReadFlattenedFileObject(buf)
 684                 payloadLen := len(ffo.Payload())
 685                 fileSize := int(binary.BigEndian.Uint32(ffo.FlatFileDataForkHeader.DataSize))
 686
 687                 destinationFile := s.Config.FileRoot + ReadFilePath(fileTransfer.FilePath) + "/" + string(fileTransfer.FileName)
 688                 s.Logger.Infow(
 689                         "File upload started",
 690                         "transactionRef", fileTransfer.ReferenceNumber,
 691                         "RemoteAddr", conn.RemoteAddr().String(),
 692                         "size", fileSize,
 693                         "dstFile", destinationFile,
 694                 )
 695
 696                 newFile, err := os.Create(destinationFile)
 697                 if err != nil {
 698                         return err
 699                 }
 700
 701                 defer func() { _ = newFile.Close() }()
 702
 703                 const buffSize = 1024
 704
 705                 if _, err := newFile.Write(buf[payloadLen:]); err != nil {
 706                         return err
 707                 }
 708                 receivedBytes := buffSize - payloadLen
 709
 710                 for {
 711                         if (fileSize - receivedBytes) < buffSize {
 712                                 s.Logger.Infow(
 713                                         "File upload complete",
 714                                         "transactionRef", fileTransfer.ReferenceNumber,
 715                                         "RemoteAddr", conn.RemoteAddr().String(),
 716                                         "size", fileSize,
 717                                         "dstFile", destinationFile,
 718                                 )
 719
 720                                 if _, err := io.CopyN(newFile, conn, int64(fileSize-receivedBytes)); err != nil {
 721                                         return fmt.Errorf("file transfer failed: %s", err)
 722                                 }
 723                                 return nil
 724                         }
 725
 726                         // Copy N bytes from conn to upload file
 727                         n, err := io.CopyN(newFile, conn, buffSize)
 728                         if err != nil {
 729                                 return err
 730                         }
 731                         receivedBytes += int(n)
 732                 }
 733         case FolderDownload:
 734                 // Folder Download flow:
 735                 // 1. Get filePath from the transfer
 736                 // 2. Iterate over files
 737                 // 3. For each file:
 738                 //       Send file header to client
 739                 // The client can reply in 3 ways:
 740                 //
 741                 // 1. If type is an odd number (unknown type?), or file download for the current file is completed:
 742                 //              client sends []byte{0x00, 0x03} to tell the server to continue to the next file
 743                 //
 744                 // 2. If download of a file is to be resumed:
 745                 //              client sends:
 746                 //                      []byte{0x00, 0x02} // download folder action
 747                 //                      [2]byte // Resume data size
 748                 //                      []byte file resume data (see myField_FileResumeData)
 749                 //
 750                 // 3. Otherwise download of the file is requested and client sends []byte{0x00, 0x01}
 751                 //
 752                 // When download is requested (case 2 or 3), server replies with:
 753                 //                      [4]byte - file size
 754                 //                      []byte  - Flattened File Object
 755                 //
 756                 // After every file download, client could request next file with:
 757                 //                      []byte{0x00, 0x03}
 758                 //
 759                 // This notifies the server to send the next item header
 760
 761                 var fh FilePath
 762                 _ = fh.UnmarshalBinary(fileTransfer.FilePath)
 763                 fullFilePath := fmt.Sprintf("%v/%v", s.Config.FileRoot+fh.String(), string(fileTransfer.FileName))
 764
 765                 basePathLen := len(fullFilePath)
 766
 767                 readBuffer := make([]byte, 1024)
 768
 769                 s.Logger.Infow("Start folder download", "path", fullFilePath, "ReferenceNumber", fileTransfer.ReferenceNumber, "RemoteAddr", conn.RemoteAddr())
 770
 771                 i := 0
 772                 _ = filepath.Walk(fullFilePath+"/", func(path string, info os.FileInfo, _ error) error {
 773                         i += 1
 774                         subPath := path[basePathLen:]
 775                         s.Logger.Infow("Sending fileheader", "i", i, "path", path, "fullFilePath", fullFilePath, "subPath", subPath, "IsDir", info.IsDir())
 776
 777                         fileHeader := NewFileHeader(subPath, info.IsDir())
 778
 779                         if i == 1 {
 780                                 return nil
 781                         }
 782
 783                         // Send the file header to client
 784                         if _, err := conn.Write(fileHeader.Payload()); err != nil {
 785                                 s.Logger.Errorf("error sending file header: %v", err)
 786                                 return err
 787                         }
 788
 789                         // Read the client's Next Action request
 790                         //TODO: Remove hardcoded behavior and switch behaviors based on the next action send
 791                         if _, err := conn.Read(readBuffer); err != nil {
 792                                 s.Logger.Errorf("error reading next action: %v", err)
 793                                 return err
 794                         }
 795
 796                         s.Logger.Infow("Client folder download action", "action", fmt.Sprintf("%X", readBuffer[0:2]))
 797
 798                         if info.IsDir() {
 799                                 return nil
 800                         }
 801
 802                         splitPath := strings.Split(path, "/")
 803                         //strings.Join(splitPath[:len(splitPath)-1], "/")
 804
 805                         ffo, err := NewFlattenedFileObject(strings.Join(splitPath[:len(splitPath)-1], "/"), info.Name())
 806                         if err != nil {
 807                                 return err
 808                         }
 809                         s.Logger.Infow("File download started",
 810                                 "fileName", info.Name(),
 811                                 "transactionRef", fileTransfer.ReferenceNumber,
 812                                 "RemoteAddr", conn.RemoteAddr().String(),
 813                                 "TransferSize", fmt.Sprintf("%x", ffo.TransferSize()),
 814                         )
 815
 816                         // Send file size to client
 817                         if _, err := conn.Write(ffo.TransferSize()); err != nil {
 818                                 s.Logger.Error(err)
 819                                 return err
 820                         }
 821
 822                         // Send file bytes to client
 823                         if _, err := conn.Write(ffo.Payload()); err != nil {
 824                                 s.Logger.Error(err)
 825                                 return err
 826                         }
 827
 828                         file, err := os.Open(path)
 829                         if err != nil {
 830                                 return err
 831                         }
 832
 833                         sendBuffer := make([]byte, 1048576)
 834                         totalBytesSent := len(ffo.Payload())
 835
 836                         for {
 837                                 bytesRead, err := file.Read(sendBuffer)
 838                                 if err == io.EOF {
 839                                         // Read the client's Next Action request
 840                                         //TODO: Remove hardcoded behavior and switch behaviors based on the next action send
 841                                         if _, err := conn.Read(readBuffer); err != nil {
 842                                                 s.Logger.Errorf("error reading next action: %v", err)
 843                                                 return err
 844                                         }
 845                                         break
 846                                 }
 847
 848                                 sentBytes, readErr := conn.Write(sendBuffer[:bytesRead])
 849                                 totalBytesSent += sentBytes
 850                                 if readErr != nil {
 851                                         return err
 852                                 }
 853                         }
 854                         return nil
 855                 })
 856
 857         case FolderUpload:
 858                 dstPath := s.Config.FileRoot + ReadFilePath(fileTransfer.FilePath) + "/" + string(fileTransfer.FileName)
 859                 s.Logger.Infow(
 860                         "Folder upload started",
 861                         "transactionRef", fileTransfer.ReferenceNumber,
 862                         "RemoteAddr", conn.RemoteAddr().String(),
 863                         "dstPath", dstPath,
 864                         "TransferSize", fileTransfer.TransferSize,
 865                         "FolderItemCount", fileTransfer.FolderItemCount,
 866                 )
 867
 868                 // Check if the target folder exists.  If not, create it.
 869                 if _, err := os.Stat(dstPath); os.IsNotExist(err) {
 870                         s.Logger.Infow("Target path does not exist; Creating...", "dstPath", dstPath)
 871                         if err := os.Mkdir(dstPath, 0777); err != nil {
 872                                 s.Logger.Error(err)
 873                         }
 874                 }
 875
 876                 readBuffer := make([]byte, 1024)
 877
 878                 // Begin the folder upload flow by sending the "next file action" to client
 879                 if _, err := conn.Write([]byte{0, dlFldrActionNextFile}); err != nil {
 880                         return err
 881                 }
 882
 883                 fileSize := make([]byte, 4)
 884                 itemCount := binary.BigEndian.Uint16(fileTransfer.FolderItemCount)
 885
 886                 for i := uint16(0); i < itemCount; i++ {
 887                         if _, err := conn.Read(readBuffer); err != nil {
 888                                 return err
 889                         }
 890                         fu := readFolderUpload(readBuffer)
 891
 892                         s.Logger.Infow(
 893                                 "Folder upload continued",
 894                                 "transactionRef", fmt.Sprintf("%x", fileTransfer.ReferenceNumber),
 895                                 "RemoteAddr", conn.RemoteAddr().String(),
 896                                 "FormattedPath", fu.FormattedPath(),
 897                                 "IsFolder", fmt.Sprintf("%x", fu.IsFolder),
 898                                 "PathItemCount", binary.BigEndian.Uint16(fu.PathItemCount),
 899                         )
 900
 901                         if bytes.Equal(fu.IsFolder, []byte{0, 1}) {
 902                                 if _, err := os.Stat(dstPath + "/" + fu.FormattedPath()); os.IsNotExist(err) {
 903                                         s.Logger.Infow("Target path does not exist; Creating...", "dstPath", dstPath)
 904                                         if err := os.Mkdir(dstPath+"/"+fu.FormattedPath(), 0777); err != nil {
 905                                                 s.Logger.Error(err)
 906                                         }
 907                                 }
 908
 909                                 // Tell client to send next file
 910                                 if _, err := conn.Write([]byte{0, dlFldrActionNextFile}); err != nil {
 911                                         s.Logger.Error(err)
 912                                         return err
 913                                 }
 914                         } else {
 915                                 // TODO: Check if we have the full file already.  If so, send dlFldrAction_NextFile to client to skip.
 916                                 // TODO: Check if we have a partial file already.  If so, send dlFldrAction_ResumeFile to client to resume upload.
 917                                 // Send dlFldrAction_SendFile to client to begin transfer
 918                                 if _, err := conn.Write([]byte{0, dlFldrActionSendFile}); err != nil {
 919                                         return err
 920                                 }
 921
 922                                 if _, err := conn.Read(fileSize); err != nil {
 923                                         fmt.Println("Error reading:", err.Error()) // TODO: handle
 924                                 }
 925
 926                                 s.Logger.Infow("Starting file transfer", "fileNum", i+1, "totalFiles", itemCount, "fileSize", fileSize)
 927
 928                                 if err := transferFile(conn, dstPath+"/"+fu.FormattedPath()); err != nil {
 929                                         s.Logger.Error(err)
 930                                 }
 931
 932                                 // Tell client to send next file
 933                                 if _, err := conn.Write([]byte{0, dlFldrActionNextFile}); err != nil {
 934                                         s.Logger.Error(err)
 935                                         return err
 936                                 }
 937
 938                                 // Client sends "MACR" after the file.  Read and discard.
 939                                 // TODO: This doesn't seem to be documented.  What is this?  Maybe resource fork?
 940                                 if _, err := conn.Read(readBuffer); err != nil {
 941                                         return err
 942                                 }
 943                         }
 944                 }
 945                 s.Logger.Infof("Folder upload complete")
 946         }
 947
 948         return nil
 949 }
 950
 951 func transferFile(conn net.Conn, dst string) error {
 952         const buffSize = 1024
 953         buf := make([]byte, buffSize)
 954
 955         // Read first chunk of bytes from conn; this will be the Flat File Object and initial chunk of file bytes
 956         if _, err := conn.Read(buf); err != nil {
 957                 return err
 958         }
 959         ffo := ReadFlattenedFileObject(buf)
 960         payloadLen := len(ffo.Payload())
 961         fileSize := int(binary.BigEndian.Uint32(ffo.FlatFileDataForkHeader.DataSize))
 962
 963         newFile, err := os.Create(dst)
 964         if err != nil {
 965                 return err
 966         }
 967         defer func() { _ = newFile.Close() }()
 968         if _, err := newFile.Write(buf[payloadLen:]); err != nil {
 969                 return err
 970         }
 971         receivedBytes := buffSize - payloadLen
 972
 973         for {
 974                 if (fileSize - receivedBytes) < buffSize {
 975                         _, err := io.CopyN(newFile, conn, int64(fileSize-receivedBytes))
 976                         return err
 977                 }
 978
 979                 // Copy N bytes from conn to upload file
 980                 n, err := io.CopyN(newFile, conn, buffSize)
 981                 if err != nil {
 982                         return err
 983                 }
 984                 receivedBytes += int(n)
 985         }
 986 }
 987
 988 // 00 28 // DataSize
 989 // 00 00 // IsFolder
 990 // 00 02 // PathItemCount
 991 //
 992 // 00 00
 993 // 09
 994 // 73 75 62 66 6f 6c 64 65 72 // "subfolder"
 995 //
 996 // 00 00
 997 // 15
 998 // 73 75 62 66 6f 6c 64 65 72 2d 74 65 73 74 66 69 6c 65 2d 35 6b // "subfolder-testfile-5k"
 999 func readFolderUpload(buf []byte) folderUpload {
1000         dataLen := binary.BigEndian.Uint16(buf[0:2])
1001
1002         fu := folderUpload{
1003                 DataSize:      buf[0:2], // Size of this structure (not including data size element itself)
1004                 IsFolder:      buf[2:4],
1005                 PathItemCount: buf[4:6],
1006                 FileNamePath:  buf[6 : dataLen+2],
1007         }
1008
1009         return fu
1010 }
1011
1012 type folderUpload struct {
1013         DataSize      []byte
1014         IsFolder      []byte
1015         PathItemCount []byte
1016         FileNamePath  []byte
1017 }
1018
1019 func (fu *folderUpload) FormattedPath() string {
1020         pathItemLen := binary.BigEndian.Uint16(fu.PathItemCount)
1021
1022         var pathSegments []string
1023         pathData := fu.FileNamePath
1024
1025         for i := uint16(0); i < pathItemLen; i++ {
1026                 segLen := pathData[2]
1027                 pathSegments = append(pathSegments, string(pathData[3:3+segLen]))
1028                 pathData = pathData[3+segLen:]
1029         }
1030
1031         return strings.Join(pathSegments, pathSeparator)
1032 }
1033
1034 // sortedClients is a utility function that takes a map of *ClientConn and returns a sorted slice of the values.
1035 // The purpose of this is to ensure that the ordering of client connections is deterministic so that test assertions work.
1036 func sortedClients(unsortedClients map[uint16]*ClientConn) (clients []*ClientConn) {
1037         for _, c := range unsortedClients {
1038                 clients = append(clients, c)
1039         }
1040         sort.Sort(byClientID(clients))
1041         return clients
1042 }