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

   1 package hotline
   2
   3 import (
   4         "context"
   5         "encoding/binary"
   6         "errors"
   7         "fmt"
   8         "github.com/go-playground/validator/v10"
   9         "go.uber.org/zap"
  10         "io"
  11         "io/fs"
  12         "io/ioutil"
  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         "gopkg.in/yaml.v3"
  26 )
  27
  28 const (
  29         userIdleSeconds        = 300 // time in seconds before an inactive user is marked idle
  30         idleCheckInterval      = 10  // time in seconds to check for idle users
  31         trackerUpdateFrequency = 300 // time in seconds between tracker re-registration
  32 )
  33
  34 type Server struct {
  35         Port          int
  36         Accounts      map[string]*Account
  37         Agreement     []byte
  38         Clients       map[uint16]*ClientConn
  39         FlatNews      []byte
  40         ThreadedNews  *ThreadedNews
  41         FileTransfers map[uint32]*FileTransfer
  42         Config        *Config
  43         ConfigDir     string
  44         Logger        *zap.SugaredLogger
  45         PrivateChats  map[uint32]*PrivateChat
  46         NextGuestID   *uint16
  47         TrackerPassID [4]byte
  48         Stats         *Stats
  49
  50         APIListener  net.Listener
  51         FileListener net.Listener
  52
  53         // newsReader io.Reader
  54         // newsWriter io.WriteCloser
  55
  56         outbox chan Transaction
  57
  58         mux         sync.Mutex
  59         flatNewsMux sync.Mutex
  60 }
  61
  62 type PrivateChat struct {
  63         Subject    string
  64         ClientConn map[uint16]*ClientConn
  65 }
  66
  67 func (s *Server) ListenAndServe(ctx context.Context, cancelRoot context.CancelFunc) error {
  68         s.Logger.Infow("Hotline server started",
  69                 "version", VERSION,
  70                 "API port", fmt.Sprintf(":%v", s.Port),
  71                 "Transfer port", fmt.Sprintf(":%v", s.Port+1),
  72         )
  73
  74         var wg sync.WaitGroup
  75
  76         wg.Add(1)
  77         go func() { s.Logger.Fatal(s.Serve(ctx, cancelRoot, s.APIListener)) }()
  78
  79         wg.Add(1)
  80         go func() { s.Logger.Fatal(s.ServeFileTransfers(s.FileListener)) }()
  81
  82         wg.Wait()
  83
  84         return nil
  85 }
  86
  87 func (s *Server) ServeFileTransfers(ln net.Listener) error {
  88         for {
  89                 conn, err := ln.Accept()
  90                 if err != nil {
  91                         return err
  92                 }
  93
  94                 go func() {
  95                         if err := s.handleFileTransfer(conn); err != nil {
  96                                 s.Logger.Errorw("file transfer error", "reason", err)
  97                         }
  98                 }()
  99         }
 100 }
 101
 102 func (s *Server) sendTransaction(t Transaction) error {
 103         requestNum := binary.BigEndian.Uint16(t.Type)
 104         clientID, err := byteToInt(*t.clientID)
 105         if err != nil {
 106                 return err
 107         }
 108
 109         s.mux.Lock()
 110         client := s.Clients[uint16(clientID)]
 111         s.mux.Unlock()
 112         if client == nil {
 113                 return fmt.Errorf("invalid client id %v", *t.clientID)
 114         }
 115         userName := string(client.UserName)
 116         login := client.Account.Login
 117
 118         handler := TransactionHandlers[requestNum]
 119
 120         b, err := t.MarshalBinary()
 121         if err != nil {
 122                 return err
 123         }
 124         var n int
 125         if n, err = client.Connection.Write(b); err != nil {
 126                 return err
 127         }
 128         s.Logger.Debugw("Sent Transaction",
 129                 "name", userName,
 130                 "login", login,
 131                 "IsReply", t.IsReply,
 132                 "type", handler.Name,
 133                 "sentBytes", n,
 134                 "remoteAddr", client.RemoteAddr,
 135         )
 136         return nil
 137 }
 138
 139 func (s *Server) Serve(ctx context.Context, cancelRoot context.CancelFunc, ln net.Listener) error {
 140
 141         for {
 142                 conn, err := ln.Accept()
 143                 if err != nil {
 144                         s.Logger.Errorw("error accepting connection", "err", err)
 145                 }
 146
 147                 go func() {
 148                         for {
 149                                 t := <-s.outbox
 150                                 go func() {
 151                                         if err := s.sendTransaction(t); err != nil {
 152                                                 s.Logger.Errorw("error sending transaction", "err", err)
 153                                         }
 154                                 }()
 155                         }
 156                 }()
 157                 go func() {
 158                         if err := s.handleNewConnection(conn, conn.RemoteAddr().String()); err != nil {
 159                                 if err == io.EOF {
 160                                         s.Logger.Infow("Client disconnected", "RemoteAddr", conn.RemoteAddr())
 161                                 } else {
 162                                         s.Logger.Errorw("error serving request", "RemoteAddr", conn.RemoteAddr(), "err", err)
 163                                 }
 164                         }
 165                 }()
 166         }
 167 }
 168
 169 const (
 170         agreementFile = "Agreement.txt"
 171 )
 172
 173 // NewServer constructs a new Server from a config dir
 174 func NewServer(configDir, netInterface string, netPort int, logger *zap.SugaredLogger) (*Server, error) {
 175         server := Server{
 176                 Port:          netPort,
 177                 Accounts:      make(map[string]*Account),
 178                 Config:        new(Config),
 179                 Clients:       make(map[uint16]*ClientConn),
 180                 FileTransfers: make(map[uint32]*FileTransfer),
 181                 PrivateChats:  make(map[uint32]*PrivateChat),
 182                 ConfigDir:     configDir,
 183                 Logger:        logger,
 184                 NextGuestID:   new(uint16),
 185                 outbox:        make(chan Transaction),
 186                 Stats:         &Stats{StartTime: time.Now()},
 187                 ThreadedNews:  &ThreadedNews{},
 188         }
 189
 190         ln, err := net.Listen("tcp", fmt.Sprintf("%s:%v", netInterface, netPort))
 191         if err != nil {
 192                 return nil, err
 193         }
 194         server.APIListener = ln
 195
 196         ln2, err := net.Listen("tcp", fmt.Sprintf("%s:%v", netInterface, netPort+1))
 197         server.FileListener = ln2
 198         if err != nil {
 199                 return nil, err
 200         }
 201
 202         // generate a new random passID for tracker registration
 203         if _, err := rand.Read(server.TrackerPassID[:]); err != nil {
 204                 return nil, err
 205         }
 206
 207         if server.Agreement, err = os.ReadFile(configDir + agreementFile); err != nil {
 208                 return nil, err
 209         }
 210
 211         if server.FlatNews, err = os.ReadFile(configDir + "MessageBoard.txt"); err != nil {
 212                 return nil, err
 213         }
 214
 215         if err := server.loadThreadedNews(configDir + "ThreadedNews.yaml"); err != nil {
 216                 return nil, err
 217         }
 218
 219         if err := server.loadConfig(configDir + "config.yaml"); err != nil {
 220                 return nil, err
 221         }
 222
 223         if err := server.loadAccounts(configDir + "Users/"); err != nil {
 224                 return nil, err
 225         }
 226
 227         server.Config.FileRoot = configDir + "Files/"
 228
 229         *server.NextGuestID = 1
 230
 231         if server.Config.EnableTrackerRegistration {
 232                 server.Logger.Infow(
 233                         "Tracker registration enabled",
 234                         "frequency", fmt.Sprintf("%vs", trackerUpdateFrequency),
 235                         "trackers", server.Config.Trackers,
 236                 )
 237
 238                 go func() {
 239                         for {
 240                                 tr := &TrackerRegistration{
 241                                         UserCount:   server.userCount(),
 242                                         PassID:      server.TrackerPassID[:],
 243                                         Name:        server.Config.Name,
 244                                         Description: server.Config.Description,
 245                                 }
 246                                 binary.BigEndian.PutUint16(tr.Port[:], uint16(server.Port))
 247                                 for _, t := range server.Config.Trackers {
 248                                         if err := register(t, tr); err != nil {
 249                                                 server.Logger.Errorw("unable to register with tracker %v", "error", err)
 250                                         }
 251                                         server.Logger.Infow("Sent Tracker registration", "data", tr)
 252                                 }
 253
 254                                 time.Sleep(trackerUpdateFrequency * time.Second)
 255                         }
 256                 }()
 257         }
 258
 259         // Start Client Keepalive go routine
 260         go server.keepaliveHandler()
 261
 262         return &server, nil
 263 }
 264
 265 func (s *Server) userCount() int {
 266         s.mux.Lock()
 267         defer s.mux.Unlock()
 268
 269         return len(s.Clients)
 270 }
 271
 272 func (s *Server) keepaliveHandler() {
 273         for {
 274                 time.Sleep(idleCheckInterval * time.Second)
 275                 s.mux.Lock()
 276
 277                 for _, c := range s.Clients {
 278                         c.IdleTime += idleCheckInterval
 279                         if c.IdleTime > userIdleSeconds && !c.Idle {
 280                                 c.Idle = true
 281
 282                                 flagBitmap := big.NewInt(int64(binary.BigEndian.Uint16(*c.Flags)))
 283                                 flagBitmap.SetBit(flagBitmap, userFlagAway, 1)
 284                                 binary.BigEndian.PutUint16(*c.Flags, uint16(flagBitmap.Int64()))
 285
 286                                 c.sendAll(
 287                                         tranNotifyChangeUser,
 288                                         NewField(fieldUserID, *c.ID),
 289                                         NewField(fieldUserFlags, *c.Flags),
 290                                         NewField(fieldUserName, c.UserName),
 291                                         NewField(fieldUserIconID, *c.Icon),
 292                                 )
 293                         }
 294                 }
 295                 s.mux.Unlock()
 296         }
 297 }
 298
 299 func (s *Server) writeThreadedNews() error {
 300         s.mux.Lock()
 301         defer s.mux.Unlock()
 302
 303         out, err := yaml.Marshal(s.ThreadedNews)
 304         if err != nil {
 305                 return err
 306         }
 307         err = ioutil.WriteFile(
 308                 s.ConfigDir+"ThreadedNews.yaml",
 309                 out,
 310                 0666,
 311         )
 312         return err
 313 }
 314
 315 func (s *Server) NewClientConn(conn net.Conn, remoteAddr string) *ClientConn {
 316         s.mux.Lock()
 317         defer s.mux.Unlock()
 318
 319         clientConn := &ClientConn{
 320                 ID:         &[]byte{0, 0},
 321                 Icon:       &[]byte{0, 0},
 322                 Flags:      &[]byte{0, 0},
 323                 UserName:   []byte{},
 324                 Connection: conn,
 325                 Server:     s,
 326                 Version:    &[]byte{},
 327                 AutoReply:  []byte{},
 328                 Transfers:  make(map[int][]*FileTransfer),
 329                 Agreed:     false,
 330                 RemoteAddr: remoteAddr,
 331         }
 332         *s.NextGuestID++
 333         ID := *s.NextGuestID
 334
 335         binary.BigEndian.PutUint16(*clientConn.ID, ID)
 336         s.Clients[ID] = clientConn
 337
 338         return clientConn
 339 }
 340
 341 // NewUser creates a new user account entry in the server map and config file
 342 func (s *Server) NewUser(login, name, password string, access []byte) error {
 343         s.mux.Lock()
 344         defer s.mux.Unlock()
 345
 346         account := Account{
 347                 Login:    login,
 348                 Name:     name,
 349                 Password: hashAndSalt([]byte(password)),
 350                 Access:   &access,
 351         }
 352         out, err := yaml.Marshal(&account)
 353         if err != nil {
 354                 return err
 355         }
 356         s.Accounts[login] = &account
 357
 358         return FS.WriteFile(s.ConfigDir+"Users/"+login+".yaml", out, 0666)
 359 }
 360
 361 func (s *Server) UpdateUser(login, newLogin, name, password string, access []byte) error {
 362         s.mux.Lock()
 363         defer s.mux.Unlock()
 364
 365         fmt.Printf("login: %v, newLogin: %v: ", login, newLogin)
 366
 367         // update renames the user login
 368         if login != newLogin {
 369                 err := os.Rename(s.ConfigDir+"Users/"+login+".yaml", s.ConfigDir+"Users/"+newLogin+".yaml")
 370                 if err != nil {
 371                         return err
 372                 }
 373                 s.Accounts[newLogin] = s.Accounts[login]
 374                 delete(s.Accounts, login)
 375         }
 376
 377         account := s.Accounts[newLogin]
 378         account.Access = &access
 379         account.Name = name
 380         account.Password = password
 381
 382         out, err := yaml.Marshal(&account)
 383         if err != nil {
 384                 return err
 385         }
 386         if err := os.WriteFile(s.ConfigDir+"Users/"+newLogin+".yaml", out, 0666); err != nil {
 387                 return err
 388         }
 389
 390         return nil
 391 }
 392
 393 // DeleteUser deletes the user account
 394 func (s *Server) DeleteUser(login string) error {
 395         s.mux.Lock()
 396         defer s.mux.Unlock()
 397
 398         delete(s.Accounts, login)
 399
 400         return FS.Remove(s.ConfigDir + "Users/" + login + ".yaml")
 401 }
 402
 403 func (s *Server) connectedUsers() []Field {
 404         s.mux.Lock()
 405         defer s.mux.Unlock()
 406
 407         var connectedUsers []Field
 408         for _, c := range sortedClients(s.Clients) {
 409                 if !c.Agreed {
 410                         continue
 411                 }
 412                 user := User{
 413                         ID:    *c.ID,
 414                         Icon:  *c.Icon,
 415                         Flags: *c.Flags,
 416                         Name:  string(c.UserName),
 417                 }
 418                 connectedUsers = append(connectedUsers, NewField(fieldUsernameWithInfo, user.Payload()))
 419         }
 420         return connectedUsers
 421 }
 422
 423 // loadThreadedNews loads the threaded news data from disk
 424 func (s *Server) loadThreadedNews(threadedNewsPath string) error {
 425         fh, err := os.Open(threadedNewsPath)
 426         if err != nil {
 427                 return err
 428         }
 429         decoder := yaml.NewDecoder(fh)
 430
 431         return decoder.Decode(s.ThreadedNews)
 432 }
 433
 434 // loadAccounts loads account data from disk
 435 func (s *Server) loadAccounts(userDir string) error {
 436         matches, err := filepath.Glob(path.Join(userDir, "*.yaml"))
 437         if err != nil {
 438                 return err
 439         }
 440
 441         if len(matches) == 0 {
 442                 return errors.New("no user accounts found in " + userDir)
 443         }
 444
 445         for _, file := range matches {
 446                 fh, err := FS.Open(file)
 447                 if err != nil {
 448                         return err
 449                 }
 450
 451                 account := Account{}
 452                 decoder := yaml.NewDecoder(fh)
 453                 if err := decoder.Decode(&account); err != nil {
 454                         return err
 455                 }
 456
 457                 s.Accounts[account.Login] = &account
 458         }
 459         return nil
 460 }
 461
 462 func (s *Server) loadConfig(path string) error {
 463         fh, err := FS.Open(path)
 464         if err != nil {
 465                 return err
 466         }
 467
 468         decoder := yaml.NewDecoder(fh)
 469         err = decoder.Decode(s.Config)
 470         if err != nil {
 471                 return err
 472         }
 473
 474         validate := validator.New()
 475         err = validate.Struct(s.Config)
 476         if err != nil {
 477                 return err
 478         }
 479         return nil
 480 }
 481
 482 const (
 483         minTransactionLen = 22 // minimum length of any transaction
 484 )
 485
 486 // dontPanic recovers and logs panics instead of crashing
 487 // TODO: remove this after known issues are fixed
 488 func dontPanic(logger *zap.SugaredLogger) {
 489         if r := recover(); r != nil {
 490                 fmt.Println("stacktrace from panic: \n" + string(debug.Stack()))
 491                 logger.Errorw("PANIC", "err", r, "trace", string(debug.Stack()))
 492         }
 493 }
 494
 495 // handleNewConnection takes a new net.Conn and performs the initial login sequence
 496 func (s *Server) handleNewConnection(conn net.Conn, remoteAddr string) error {
 497         defer dontPanic(s.Logger)
 498
 499         if err := Handshake(conn); err != nil {
 500                 return err
 501         }
 502
 503         buf := make([]byte, 1024)
 504         // TODO: fix potential short read with io.ReadFull
 505         readLen, err := conn.Read(buf)
 506         if readLen < minTransactionLen {
 507                 return err
 508         }
 509         if err != nil {
 510                 return err
 511         }
 512
 513         clientLogin, _, err := ReadTransaction(buf[:readLen])
 514         if err != nil {
 515                 return err
 516         }
 517
 518         c := s.NewClientConn(conn, remoteAddr)
 519         defer c.Disconnect()
 520
 521         encodedLogin := clientLogin.GetField(fieldUserLogin).Data
 522         encodedPassword := clientLogin.GetField(fieldUserPassword).Data
 523         *c.Version = clientLogin.GetField(fieldVersion).Data
 524
 525         var login string
 526         for _, char := range encodedLogin {
 527                 login += string(rune(255 - uint(char)))
 528         }
 529         if login == "" {
 530                 login = GuestAccount
 531         }
 532
 533         // If authentication fails, send error reply and close connection
 534         if !c.Authenticate(login, encodedPassword) {
 535                 t := c.NewErrReply(clientLogin, "Incorrect login.")
 536                 b, err := t.MarshalBinary()
 537                 if err != nil {
 538                         return err
 539                 }
 540                 if _, err := conn.Write(b); err != nil {
 541                         return err
 542                 }
 543                 return fmt.Errorf("incorrect login")
 544         }
 545
 546         if clientLogin.GetField(fieldUserName).Data != nil {
 547                 c.UserName = clientLogin.GetField(fieldUserName).Data
 548         }
 549
 550         if clientLogin.GetField(fieldUserIconID).Data != nil {
 551                 *c.Icon = clientLogin.GetField(fieldUserIconID).Data
 552         }
 553
 554         c.Account = c.Server.Accounts[login]
 555
 556         if c.Authorize(accessDisconUser) {
 557                 *c.Flags = []byte{0, 2}
 558         }
 559
 560         s.Logger.Infow("Client connection received", "login", login, "version", *c.Version, "RemoteAddr", remoteAddr)
 561
 562         s.outbox <- c.NewReply(clientLogin,
 563                 NewField(fieldVersion, []byte{0x00, 0xbe}),
 564                 NewField(fieldCommunityBannerID, []byte{0x00, 0x01}),
 565                 NewField(fieldServerName, []byte(s.Config.Name)),
 566         )
 567
 568         // Send user access privs so client UI knows how to behave
 569         c.Server.outbox <- *NewTransaction(tranUserAccess, c.ID, NewField(fieldUserAccess, *c.Account.Access))
 570
 571         // Show agreement to client
 572         c.Server.outbox <- *NewTransaction(tranShowAgreement, c.ID, NewField(fieldData, s.Agreement))
 573
 574         // assume simplified hotline v1.2.3 login flow that does not require agreement
 575         if *c.Version == nil {
 576                 c.Agreed = true
 577
 578                 c.notifyOthers(
 579                         *NewTransaction(
 580                                 tranNotifyChangeUser, nil,
 581                                 NewField(fieldUserName, c.UserName),
 582                                 NewField(fieldUserID, *c.ID),
 583                                 NewField(fieldUserIconID, *c.Icon),
 584                                 NewField(fieldUserFlags, *c.Flags),
 585                         ),
 586                 )
 587         }
 588
 589         c.Server.Stats.LoginCount += 1
 590
 591         const readBuffSize = 1024000 // 1KB - TODO: what should this be?
 592         tranBuff := make([]byte, 0)
 593         tReadlen := 0
 594         // Infinite loop where take action on incoming client requests until the connection is closed
 595         for {
 596                 buf = make([]byte, readBuffSize)
 597                 tranBuff = tranBuff[tReadlen:]
 598
 599                 readLen, err := c.Connection.Read(buf)
 600                 if err != nil {
 601                         return err
 602                 }
 603                 tranBuff = append(tranBuff, buf[:readLen]...)
 604
 605                 // We may have read multiple requests worth of bytes from Connection.Read.  readTransactions splits them
 606                 // into a slice of transactions
 607                 var transactions []Transaction
 608                 if transactions, tReadlen, err = readTransactions(tranBuff); err != nil {
 609                         c.Server.Logger.Errorw("Error handling transaction", "err", err)
 610                 }
 611
 612                 // iterate over all of the transactions that were parsed from the byte slice and handle them
 613                 for _, t := range transactions {
 614                         if err := c.handleTransaction(&t); err != nil {
 615                                 c.Server.Logger.Errorw("Error handling transaction", "err", err)
 616                         }
 617                 }
 618         }
 619 }
 620
 621 // NewTransactionRef generates a random ID for the file transfer.  The Hotline client includes this ID
 622 // in the file transfer request payload, and the file transfer server will use it to map the request
 623 // to a transfer
 624 func (s *Server) NewTransactionRef() []byte {
 625         transactionRef := make([]byte, 4)
 626         rand.Read(transactionRef)
 627
 628         return transactionRef
 629 }
 630
 631 func (s *Server) NewPrivateChat(cc *ClientConn) []byte {
 632         s.mux.Lock()
 633         defer s.mux.Unlock()
 634
 635         randID := make([]byte, 4)
 636         rand.Read(randID)
 637         data := binary.BigEndian.Uint32(randID[:])
 638
 639         s.PrivateChats[data] = &PrivateChat{
 640                 Subject:    "",
 641                 ClientConn: make(map[uint16]*ClientConn),
 642         }
 643         s.PrivateChats[data].ClientConn[cc.uint16ID()] = cc
 644
 645         return randID
 646 }
 647
 648 const dlFldrActionSendFile = 1
 649 const dlFldrActionResumeFile = 2
 650 const dlFldrActionNextFile = 3
 651
 652 // handleFileTransfer receives a client net.Conn from the file transfer server, performs the requested transfer type, then closes the connection
 653 func (s *Server) handleFileTransfer(conn io.ReadWriteCloser) error {
 654         defer func() {
 655
 656                 if err := conn.Close(); err != nil {
 657                         s.Logger.Errorw("error closing connection", "error", err)
 658                 }
 659         }()
 660
 661         defer dontPanic(s.Logger)
 662
 663         txBuf := make([]byte, 16)
 664         if _, err := io.ReadFull(conn, txBuf); err != nil {
 665                 return err
 666         }
 667
 668         var t transfer
 669         if _, err := t.Write(txBuf); err != nil {
 670                 return err
 671         }
 672
 673         transferRefNum := binary.BigEndian.Uint32(t.ReferenceNumber[:])
 674         defer func() {
 675                 s.mux.Lock()
 676                 delete(s.FileTransfers, transferRefNum)
 677                 s.mux.Unlock()
 678         }()
 679
 680         s.mux.Lock()
 681         fileTransfer, ok := s.FileTransfers[transferRefNum]
 682         s.mux.Unlock()
 683         if !ok {
 684                 return errors.New("invalid transaction ID")
 685         }
 686
 687         switch fileTransfer.Type {
 688         case FileDownload:
 689                 fullFilePath, err := readPath(s.Config.FileRoot, fileTransfer.FilePath, fileTransfer.FileName)
 690                 if err != nil {
 691                         return err
 692                 }
 693
 694                 var dataOffset int64
 695                 if fileTransfer.fileResumeData != nil {
 696                         dataOffset = int64(binary.BigEndian.Uint32(fileTransfer.fileResumeData.ForkInfoList[0].DataSize[:]))
 697                 }
 698
 699                 ffo, err := NewFlattenedFileObject(s.Config.FileRoot, fileTransfer.FilePath, fileTransfer.FileName, dataOffset)
 700                 if err != nil {
 701                         return err
 702                 }
 703
 704                 s.Logger.Infow("File download started", "filePath", fullFilePath, "transactionRef", fileTransfer.ReferenceNumber)
 705
 706                 if fileTransfer.options == nil {
 707                         // Start by sending flat file object to client
 708                         if _, err := conn.Write(ffo.BinaryMarshal()); err != nil {
 709                                 return err
 710                         }
 711                 }
 712
 713                 file, err := FS.Open(fullFilePath)
 714                 if err != nil {
 715                         return err
 716                 }
 717
 718                 sendBuffer := make([]byte, 1048576)
 719                 var totalSent int64
 720                 for {
 721                         var bytesRead int
 722                         if bytesRead, err = file.ReadAt(sendBuffer, dataOffset+totalSent); err == io.EOF {
 723                                 if _, err := conn.Write(sendBuffer[:bytesRead]); err != nil {
 724                                         return err
 725                                 }
 726                                 break
 727                         }
 728                         if err != nil {
 729                                 return err
 730                         }
 731                         totalSent += int64(bytesRead)
 732
 733                         fileTransfer.BytesSent += bytesRead
 734
 735                         if _, err := conn.Write(sendBuffer[:bytesRead]); err != nil {
 736                                 return err
 737                         }
 738                 }
 739         case FileUpload:
 740                 destinationFile := s.Config.FileRoot + ReadFilePath(fileTransfer.FilePath) + "/" + string(fileTransfer.FileName)
 741
 742                 var file *os.File
 743
 744                 // A file upload has three possible cases:
 745                 // 1) Upload a new file
 746                 // 2) Resume a partially transferred file
 747                 // 3) Replace a fully uploaded file
 748                 // Unfortunately we have to infer which case applies by inspecting what is already on the file system
 749
 750                 // 1) Check for existing file:
 751                 _, err := os.Stat(destinationFile)
 752                 if err == nil {
 753                         // If found, that means this upload is intended to replace the file
 754                         if err = os.Remove(destinationFile); err != nil {
 755                                 return err
 756                         }
 757                         file, err = os.Create(destinationFile + incompleteFileSuffix)
 758                 }
 759                 if errors.Is(err, fs.ErrNotExist) {
 760                         // If not found, open or create a new incomplete file
 761                         file, err = os.OpenFile(destinationFile+incompleteFileSuffix, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0644)
 762                         if err != nil {
 763                                 return err
 764                         }
 765                 }
 766
 767                 defer func() { _ = file.Close() }()
 768
 769                 s.Logger.Infow("File upload started", "transactionRef", fileTransfer.ReferenceNumber, "dstFile", destinationFile)
 770
 771                 // TODO: replace io.Discard with a real file when ready to implement storing of resource fork data
 772                 if err := receiveFile(conn, file, io.Discard); err != nil {
 773                         return err
 774                 }
 775
 776                 if err := os.Rename(destinationFile+".incomplete", destinationFile); err != nil {
 777                         return err
 778                 }
 779
 780                 s.Logger.Infow("File upload complete", "transactionRef", fileTransfer.ReferenceNumber, "dstFile", destinationFile)
 781         case FolderDownload:
 782                 // Folder Download flow:
 783                 // 1. Get filePath from the transfer
 784                 // 2. Iterate over files
 785                 // 3. For each file:
 786                 //       Send file header to client
 787                 // The client can reply in 3 ways:
 788                 //
 789                 // 1. If type is an odd number (unknown type?), or file download for the current file is completed:
 790                 //              client sends []byte{0x00, 0x03} to tell the server to continue to the next file
 791                 //
 792                 // 2. If download of a file is to be resumed:
 793                 //              client sends:
 794                 //                      []byte{0x00, 0x02} // download folder action
 795                 //                      [2]byte // Resume data size
 796                 //                      []byte file resume data (see myField_FileResumeData)
 797                 //
 798                 // 3. Otherwise, download of the file is requested and client sends []byte{0x00, 0x01}
 799                 //
 800                 // When download is requested (case 2 or 3), server replies with:
 801                 //                      [4]byte - file size
 802                 //                      []byte  - Flattened File Object
 803                 //
 804                 // After every file download, client could request next file with:
 805                 //                      []byte{0x00, 0x03}
 806                 //
 807                 // This notifies the server to send the next item header
 808
 809                 fullFilePath, err := readPath(s.Config.FileRoot, fileTransfer.FilePath, fileTransfer.FileName)
 810                 if err != nil {
 811                         return err
 812                 }
 813
 814                 basePathLen := len(fullFilePath)
 815
 816                 s.Logger.Infow("Start folder download", "path", fullFilePath, "ReferenceNumber", fileTransfer.ReferenceNumber)
 817
 818                 nextAction := make([]byte, 2)
 819                 if _, err := io.ReadFull(conn, nextAction); err != nil {
 820                         return err
 821                 }
 822
 823                 i := 0
 824                 err = filepath.Walk(fullFilePath+"/", func(path string, info os.FileInfo, err error) error {
 825                         if err != nil {
 826                                 return err
 827                         }
 828                         i += 1
 829                         subPath := path[basePathLen+1:]
 830                         s.Logger.Infow("Sending fileheader", "i", i, "path", path, "fullFilePath", fullFilePath, "subPath", subPath, "IsDir", info.IsDir())
 831
 832                         if i == 1 {
 833                                 return nil
 834                         }
 835
 836                         fileHeader := NewFileHeader(subPath, info.IsDir())
 837
 838                         // Send the file header to client
 839                         if _, err := conn.Write(fileHeader.Payload()); err != nil {
 840                                 s.Logger.Errorf("error sending file header: %v", err)
 841                                 return err
 842                         }
 843
 844                         // Read the client's Next Action request
 845                         if _, err := io.ReadFull(conn, nextAction); err != nil {
 846                                 return err
 847                         }
 848
 849                         s.Logger.Infow("Client folder download action", "action", fmt.Sprintf("%X", nextAction[0:2]))
 850
 851                         var dataOffset int64
 852
 853                         switch nextAction[1] {
 854                         case dlFldrActionResumeFile:
 855                                 // client asked to resume this file
 856                                 var frd FileResumeData
 857                                 // get size of resumeData
 858                                 if _, err := io.ReadFull(conn, nextAction); err != nil {
 859                                         return err
 860                                 }
 861
 862                                 resumeDataLen := binary.BigEndian.Uint16(nextAction)
 863                                 resumeDataBytes := make([]byte, resumeDataLen)
 864                                 if _, err := io.ReadFull(conn, resumeDataBytes); err != nil {
 865                                         return err
 866                                 }
 867
 868                                 if err := frd.UnmarshalBinary(resumeDataBytes); err != nil {
 869                                         return err
 870                                 }
 871                                 dataOffset = int64(binary.BigEndian.Uint32(frd.ForkInfoList[0].DataSize[:]))
 872                         case dlFldrActionNextFile:
 873                                 // client asked to skip this file
 874                                 return nil
 875                         }
 876
 877                         if info.IsDir() {
 878                                 return nil
 879                         }
 880
 881                         splitPath := strings.Split(path, "/")
 882
 883                         ffo, err := NewFlattenedFileObject(strings.Join(splitPath[:len(splitPath)-1], "/"), nil, []byte(info.Name()), dataOffset)
 884                         if err != nil {
 885                                 return err
 886                         }
 887                         s.Logger.Infow("File download started",
 888                                 "fileName", info.Name(),
 889                                 "transactionRef", fileTransfer.ReferenceNumber,
 890                                 "TransferSize", fmt.Sprintf("%x", ffo.TransferSize()),
 891                         )
 892
 893                         // Send file size to client
 894                         if _, err := conn.Write(ffo.TransferSize()); err != nil {
 895                                 s.Logger.Error(err)
 896                                 return err
 897                         }
 898
 899                         // Send ffo bytes to client
 900                         if _, err := conn.Write(ffo.BinaryMarshal()); err != nil {
 901                                 s.Logger.Error(err)
 902                                 return err
 903                         }
 904
 905                         file, err := FS.Open(path)
 906                         if err != nil {
 907                                 return err
 908                         }
 909
 910                         // // Copy N bytes from file to connection
 911                         // _, err = io.CopyN(conn, file, int64(binary.BigEndian.Uint32(ffo.FlatFileDataForkHeader.DataSize[:])))
 912                         // if err != nil {
 913                         //      return err
 914                         // }
 915                         // file.Close()
 916                         sendBuffer := make([]byte, 1048576)
 917                         var totalSent int64
 918                         for {
 919                                 var bytesRead int
 920                                 if bytesRead, err = file.ReadAt(sendBuffer, dataOffset+totalSent); err == io.EOF {
 921                                         if _, err := conn.Write(sendBuffer[:bytesRead]); err != nil {
 922                                                 return err
 923                                         }
 924                                         break
 925                                 }
 926                                 if err != nil {
 927                                         panic(err)
 928                                 }
 929                                 totalSent += int64(bytesRead)
 930
 931                                 fileTransfer.BytesSent += bytesRead
 932
 933                                 if _, err := conn.Write(sendBuffer[:bytesRead]); err != nil {
 934                                         return err
 935                                 }
 936                         }
 937
 938                         // TODO: optionally send resource fork header and resource fork data
 939
 940                         // Read the client's Next Action request.  This is always 3, I think?
 941                         if _, err := io.ReadFull(conn, nextAction); err != nil {
 942                                 return err
 943                         }
 944
 945                         return nil
 946                 })
 947
 948         case FolderUpload:
 949                 dstPath, err := readPath(s.Config.FileRoot, fileTransfer.FilePath, fileTransfer.FileName)
 950                 if err != nil {
 951                         return err
 952                 }
 953                 s.Logger.Infow(
 954                         "Folder upload started",
 955                         "transactionRef", fileTransfer.ReferenceNumber,
 956                         "dstPath", dstPath,
 957                         "TransferSize", fmt.Sprintf("%x", fileTransfer.TransferSize),
 958                         "FolderItemCount", fileTransfer.FolderItemCount,
 959                 )
 960
 961                 // Check if the target folder exists.  If not, create it.
 962                 if _, err := FS.Stat(dstPath); os.IsNotExist(err) {
 963                         if err := FS.Mkdir(dstPath, 0777); err != nil {
 964                                 return err
 965                         }
 966                 }
 967
 968                 // Begin the folder upload flow by sending the "next file action" to client
 969                 if _, err := conn.Write([]byte{0, dlFldrActionNextFile}); err != nil {
 970                         return err
 971                 }
 972
 973                 fileSize := make([]byte, 4)
 974                 readBuffer := make([]byte, 1024)
 975
 976                 for i := 0; i < fileTransfer.ItemCount(); i++ {
 977                         // TODO: fix potential short read with io.ReadFull
 978                         _, err := conn.Read(readBuffer)
 979                         if err != nil {
 980                                 return err
 981                         }
 982                         fu := readFolderUpload(readBuffer)
 983
 984                         s.Logger.Infow(
 985                                 "Folder upload continued",
 986                                 "transactionRef", fmt.Sprintf("%x", fileTransfer.ReferenceNumber),
 987                                 "FormattedPath", fu.FormattedPath(),
 988                                 "IsFolder", fmt.Sprintf("%x", fu.IsFolder),
 989                                 "PathItemCount", binary.BigEndian.Uint16(fu.PathItemCount[:]),
 990                         )
 991
 992                         if fu.IsFolder == [2]byte{0, 1} {
 993                                 if _, err := os.Stat(dstPath + "/" + fu.FormattedPath()); os.IsNotExist(err) {
 994                                         if err := os.Mkdir(dstPath+"/"+fu.FormattedPath(), 0777); err != nil {
 995                                                 return err
 996                                         }
 997                                 }
 998
 999                                 // Tell client to send next file
1000                                 if _, err := conn.Write([]byte{0, dlFldrActionNextFile}); err != nil {
1001                                         return err
1002                                 }
1003                         } else {
1004                                 nextAction := dlFldrActionSendFile
1005
1006                                 // Check if we have the full file already.  If so, send dlFldrAction_NextFile to client to skip.
1007                                 _, err := os.Stat(dstPath + "/" + fu.FormattedPath())
1008                                 if err != nil && !errors.Is(err, fs.ErrNotExist) {
1009                                         return err
1010                                 }
1011                                 if err == nil {
1012                                         nextAction = dlFldrActionNextFile
1013                                 }
1014
1015                                 //  Check if we have a partial file already.  If so, send dlFldrAction_ResumeFile to client to resume upload.
1016                                 inccompleteFile, err := os.Stat(dstPath + "/" + fu.FormattedPath() + incompleteFileSuffix)
1017                                 if err != nil && !errors.Is(err, fs.ErrNotExist) {
1018                                         return err
1019                                 }
1020                                 if err == nil {
1021                                         nextAction = dlFldrActionResumeFile
1022                                 }
1023
1024                                 fmt.Printf("Next Action: %v\n", nextAction)
1025
1026                                 if _, err := conn.Write([]byte{0, uint8(nextAction)}); err != nil {
1027                                         return err
1028                                 }
1029
1030                                 switch nextAction {
1031                                 case dlFldrActionNextFile:
1032                                         continue
1033                                 case dlFldrActionResumeFile:
1034                                         offset := make([]byte, 4)
1035                                         binary.BigEndian.PutUint32(offset, uint32(inccompleteFile.Size()))
1036
1037                                         file, err := os.OpenFile(dstPath+"/"+fu.FormattedPath()+incompleteFileSuffix, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
1038                                         if err != nil {
1039                                                 return err
1040                                         }
1041
1042                                         fileResumeData := NewFileResumeData([]ForkInfoList{
1043                                                 *NewForkInfoList(offset),
1044                                         })
1045
1046                                         b, _ := fileResumeData.BinaryMarshal()
1047
1048                                         bs := make([]byte, 2)
1049                                         binary.BigEndian.PutUint16(bs, uint16(len(b)))
1050
1051                                         if _, err := conn.Write(append(bs, b...)); err != nil {
1052                                                 return err
1053                                         }
1054
1055                                         if _, err := io.ReadFull(conn, fileSize); err != nil {
1056                                                 return err
1057                                         }
1058
1059                                         if err := receiveFile(conn, file, ioutil.Discard); err != nil {
1060                                                 s.Logger.Error(err)
1061                                         }
1062
1063                                         err = os.Rename(dstPath+"/"+fu.FormattedPath()+".incomplete", dstPath+"/"+fu.FormattedPath())
1064                                         if err != nil {
1065                                                 return err
1066                                         }
1067
1068                                 case dlFldrActionSendFile:
1069                                         if _, err := conn.Read(fileSize); err != nil {
1070                                                 return err
1071                                         }
1072
1073                                         filePath := dstPath + "/" + fu.FormattedPath()
1074                                         s.Logger.Infow("Starting file transfer", "path", filePath, "fileNum", i+1, "totalFiles", "zz", "fileSize", binary.BigEndian.Uint32(fileSize))
1075
1076                                         newFile, err := FS.Create(filePath + ".incomplete")
1077                                         if err != nil {
1078                                                 return err
1079                                         }
1080
1081                                         if err := receiveFile(conn, newFile, ioutil.Discard); err != nil {
1082                                                 s.Logger.Error(err)
1083                                         }
1084                                         _ = newFile.Close()
1085                                         if err := os.Rename(filePath+".incomplete", filePath); err != nil {
1086                                                 return err
1087                                         }
1088                                 }
1089
1090                                 // Tell client to send next file
1091                                 if _, err := conn.Write([]byte{0, dlFldrActionNextFile}); err != nil {
1092                                         return err
1093                                 }
1094                         }
1095                 }
1096                 s.Logger.Infof("Folder upload complete")
1097         }
1098
1099         return nil
1100 }
1101
1102 // sortedClients is a utility function that takes a map of *ClientConn and returns a sorted slice of the values.
1103 // The purpose of this is to ensure that the ordering of client connections is deterministic so that test assertions work.
1104 func sortedClients(unsortedClients map[uint16]*ClientConn) (clients []*ClientConn) {
1105         for _, c := range unsortedClients {
1106                 clients = append(clients, c)
1107         }
1108         sort.Sort(byClientID(clients))
1109         return clients
1110 }