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

   1 package hotline
   2
   3 import (
   4         "bufio"
   5         "context"
   6         "encoding/binary"
   7         "errors"
   8         "fmt"
   9         "github.com/go-playground/validator/v10"
  10         "go.uber.org/zap"
  11         "gopkg.in/yaml.v3"
  12         "io"
  13         "io/fs"
  14         "math/big"
  15         "math/rand"
  16         "net"
  17         "os"
  18         "path/filepath"
  19         "strings"
  20         "sync"
  21         "time"
  22 )
  23
  24 type contextKey string
  25
  26 var contextKeyReq = contextKey("req")
  27
  28 type requestCtx struct {
  29         remoteAddr string
  30         login      string
  31         name       string
  32 }
  33
  34 type Server struct {
  35         Port          int
  36         Accounts      map[string]*Account
  37         Agreement     []byte
  38         Clients       map[uint16]*ClientConn
  39         fileTransfers map[[4]byte]*FileTransfer
  40
  41         Config    *Config
  42         ConfigDir string
  43         Logger    *zap.SugaredLogger
  44
  45         PrivateChatsMu sync.Mutex
  46         PrivateChats   map[uint32]*PrivateChat
  47
  48         NextGuestID   *uint16
  49         TrackerPassID [4]byte
  50
  51         StatsMu sync.Mutex
  52         Stats   *Stats
  53
  54         FS FileStore // Storage backend to use for File storage
  55
  56         outbox chan Transaction
  57         mux    sync.Mutex
  58
  59         threadedNewsMux sync.Mutex
  60         ThreadedNews    *ThreadedNews
  61
  62         flatNewsMux sync.Mutex
  63         FlatNews    []byte
  64
  65         banListMU sync.Mutex
  66         banList   map[string]*time.Time
  67 }
  68
  69 func (s *Server) CurrentStats() Stats {
  70         s.StatsMu.Lock()
  71         defer s.StatsMu.Unlock()
  72
  73         stats := s.Stats
  74         stats.CurrentlyConnected = len(s.Clients)
  75
  76         return *stats
  77 }
  78
  79 type PrivateChat struct {
  80         Subject    string
  81         ClientConn map[uint16]*ClientConn
  82 }
  83
  84 func (s *Server) ListenAndServe(ctx context.Context, cancelRoot context.CancelFunc) error {
  85         s.Logger.Infow("Hotline server started",
  86                 "version", VERSION,
  87                 "API port", fmt.Sprintf(":%v", s.Port),
  88                 "Transfer port", fmt.Sprintf(":%v", s.Port+1),
  89         )
  90
  91         var wg sync.WaitGroup
  92
  93         wg.Add(1)
  94         go func() {
  95                 ln, err := net.Listen("tcp", fmt.Sprintf("%s:%v", "", s.Port))
  96                 if err != nil {
  97                         s.Logger.Fatal(err)
  98                 }
  99
 100                 s.Logger.Fatal(s.Serve(ctx, ln))
 101         }()
 102
 103         wg.Add(1)
 104         go func() {
 105                 ln, err := net.Listen("tcp", fmt.Sprintf("%s:%v", "", s.Port+1))
 106                 if err != nil {
 107                         s.Logger.Fatal(err)
 108                 }
 109
 110                 s.Logger.Fatal(s.ServeFileTransfers(ctx, ln))
 111         }()
 112
 113         wg.Wait()
 114
 115         return nil
 116 }
 117
 118 func (s *Server) ServeFileTransfers(ctx context.Context, ln net.Listener) error {
 119         for {
 120                 conn, err := ln.Accept()
 121                 if err != nil {
 122                         return err
 123                 }
 124
 125                 go func() {
 126                         defer func() { _ = conn.Close() }()
 127
 128                         err = s.handleFileTransfer(
 129                                 context.WithValue(ctx, contextKeyReq, requestCtx{
 130                                         remoteAddr: conn.RemoteAddr().String(),
 131                                 }),
 132                                 conn,
 133                         )
 134
 135                         if err != nil {
 136                                 s.Logger.Errorw("file transfer error", "reason", err)
 137                         }
 138                 }()
 139         }
 140 }
 141
 142 func (s *Server) sendTransaction(t Transaction) error {
 143         clientID, err := byteToInt(*t.clientID)
 144         if err != nil {
 145                 return err
 146         }
 147
 148         s.mux.Lock()
 149         client := s.Clients[uint16(clientID)]
 150         s.mux.Unlock()
 151         if client == nil {
 152                 return fmt.Errorf("invalid client id %v", *t.clientID)
 153         }
 154
 155         b, err := t.MarshalBinary()
 156         if err != nil {
 157                 return err
 158         }
 159
 160         _, err = client.Connection.Write(b)
 161         if err != nil {
 162                 return err
 163         }
 164
 165         return nil
 166 }
 167
 168 func (s *Server) processOutbox() {
 169         for {
 170                 t := <-s.outbox
 171                 go func() {
 172                         if err := s.sendTransaction(t); err != nil {
 173                                 s.Logger.Errorw("error sending transaction", "err", err)
 174                         }
 175                 }()
 176         }
 177 }
 178
 179 func (s *Server) Serve(ctx context.Context, ln net.Listener) error {
 180         go s.processOutbox()
 181
 182         for {
 183                 conn, err := ln.Accept()
 184                 if err != nil {
 185                         s.Logger.Errorw("error accepting connection", "err", err)
 186                 }
 187                 connCtx := context.WithValue(ctx, contextKeyReq, requestCtx{
 188                         remoteAddr: conn.RemoteAddr().String(),
 189                 })
 190
 191                 go func() {
 192                         s.Logger.Infow("Connection established", "RemoteAddr", conn.RemoteAddr())
 193
 194                         defer conn.Close()
 195                         if err := s.handleNewConnection(connCtx, conn, conn.RemoteAddr().String()); err != nil {
 196                                 if err == io.EOF {
 197                                         s.Logger.Infow("Client disconnected", "RemoteAddr", conn.RemoteAddr())
 198                                 } else {
 199                                         s.Logger.Errorw("error serving request", "RemoteAddr", conn.RemoteAddr(), "err", err)
 200                                 }
 201                         }
 202                 }()
 203         }
 204 }
 205
 206 const (
 207         agreementFile = "Agreement.txt"
 208 )
 209
 210 // NewServer constructs a new Server from a config dir
 211 func NewServer(configDir string, netPort int, logger *zap.SugaredLogger, fs FileStore) (*Server, error) {
 212         server := Server{
 213                 Port:          netPort,
 214                 Accounts:      make(map[string]*Account),
 215                 Config:        new(Config),
 216                 Clients:       make(map[uint16]*ClientConn),
 217                 fileTransfers: make(map[[4]byte]*FileTransfer),
 218                 PrivateChats:  make(map[uint32]*PrivateChat),
 219                 ConfigDir:     configDir,
 220                 Logger:        logger,
 221                 NextGuestID:   new(uint16),
 222                 outbox:        make(chan Transaction),
 223                 Stats:         &Stats{Since: time.Now()},
 224                 ThreadedNews:  &ThreadedNews{},
 225                 FS:            fs,
 226                 banList:       make(map[string]*time.Time),
 227         }
 228
 229         var err error
 230
 231         // generate a new random passID for tracker registration
 232         if _, err := rand.Read(server.TrackerPassID[:]); err != nil {
 233                 return nil, err
 234         }
 235
 236         server.Agreement, err = os.ReadFile(filepath.Join(configDir, agreementFile))
 237         if err != nil {
 238                 return nil, err
 239         }
 240
 241         if server.FlatNews, err = os.ReadFile(filepath.Join(configDir, "MessageBoard.txt")); err != nil {
 242                 return nil, err
 243         }
 244
 245         // try to load the ban list, but ignore errors as this file may not be present or may be empty
 246         _ = server.loadBanList(filepath.Join(configDir, "Banlist.yaml"))
 247
 248         if err := server.loadThreadedNews(filepath.Join(configDir, "ThreadedNews.yaml")); err != nil {
 249                 return nil, err
 250         }
 251
 252         if err := server.loadConfig(filepath.Join(configDir, "config.yaml")); err != nil {
 253                 return nil, err
 254         }
 255
 256         if err := server.loadAccounts(filepath.Join(configDir, "Users/")); err != nil {
 257                 return nil, err
 258         }
 259
 260         server.Config.FileRoot = filepath.Join(configDir, "Files")
 261
 262         *server.NextGuestID = 1
 263
 264         if server.Config.EnableTrackerRegistration {
 265                 server.Logger.Infow(
 266                         "Tracker registration enabled",
 267                         "frequency", fmt.Sprintf("%vs", trackerUpdateFrequency),
 268                         "trackers", server.Config.Trackers,
 269                 )
 270
 271                 go func() {
 272                         for {
 273                                 tr := &TrackerRegistration{
 274                                         UserCount:   server.userCount(),
 275                                         PassID:      server.TrackerPassID[:],
 276                                         Name:        server.Config.Name,
 277                                         Description: server.Config.Description,
 278                                 }
 279                                 binary.BigEndian.PutUint16(tr.Port[:], uint16(server.Port))
 280                                 for _, t := range server.Config.Trackers {
 281                                         if err := register(t, tr); err != nil {
 282                                                 server.Logger.Errorw("unable to register with tracker %v", "error", err)
 283                                         }
 284                                         server.Logger.Debugw("Sent Tracker registration", "addr", t)
 285                                 }
 286
 287                                 time.Sleep(trackerUpdateFrequency * time.Second)
 288                         }
 289                 }()
 290         }
 291
 292         // Start Client Keepalive go routine
 293         go server.keepaliveHandler()
 294
 295         return &server, nil
 296 }
 297
 298 func (s *Server) userCount() int {
 299         s.mux.Lock()
 300         defer s.mux.Unlock()
 301
 302         return len(s.Clients)
 303 }
 304
 305 func (s *Server) keepaliveHandler() {
 306         for {
 307                 time.Sleep(idleCheckInterval * time.Second)
 308                 s.mux.Lock()
 309
 310                 for _, c := range s.Clients {
 311                         c.IdleTime += idleCheckInterval
 312                         if c.IdleTime > userIdleSeconds && !c.Idle {
 313                                 c.Idle = true
 314
 315                                 flagBitmap := big.NewInt(int64(binary.BigEndian.Uint16(c.Flags)))
 316                                 flagBitmap.SetBit(flagBitmap, userFlagAway, 1)
 317                                 binary.BigEndian.PutUint16(c.Flags, uint16(flagBitmap.Int64()))
 318
 319                                 c.sendAll(
 320                                         TranNotifyChangeUser,
 321                                         NewField(FieldUserID, *c.ID),
 322                                         NewField(FieldUserFlags, c.Flags),
 323                                         NewField(FieldUserName, c.UserName),
 324                                         NewField(FieldUserIconID, c.Icon),
 325                                 )
 326                         }
 327                 }
 328                 s.mux.Unlock()
 329         }
 330 }
 331
 332 func (s *Server) writeBanList() error {
 333         s.banListMU.Lock()
 334         defer s.banListMU.Unlock()
 335
 336         out, err := yaml.Marshal(s.banList)
 337         if err != nil {
 338                 return err
 339         }
 340         err = os.WriteFile(
 341                 filepath.Join(s.ConfigDir, "Banlist.yaml"),
 342                 out,
 343                 0666,
 344         )
 345         return err
 346 }
 347
 348 func (s *Server) writeThreadedNews() error {
 349         s.threadedNewsMux.Lock()
 350         defer s.threadedNewsMux.Unlock()
 351
 352         out, err := yaml.Marshal(s.ThreadedNews)
 353         if err != nil {
 354                 return err
 355         }
 356         err = s.FS.WriteFile(
 357                 filepath.Join(s.ConfigDir, "ThreadedNews.yaml"),
 358                 out,
 359                 0666,
 360         )
 361         return err
 362 }
 363
 364 func (s *Server) NewClientConn(conn io.ReadWriteCloser, remoteAddr string) *ClientConn {
 365         s.mux.Lock()
 366         defer s.mux.Unlock()
 367
 368         clientConn := &ClientConn{
 369                 ID:         &[]byte{0, 0},
 370                 Icon:       []byte{0, 0},
 371                 Flags:      []byte{0, 0},
 372                 UserName:   []byte{},
 373                 Connection: conn,
 374                 Server:     s,
 375                 Version:    []byte{},
 376                 AutoReply:  []byte{},
 377                 transfers:  map[int]map[[4]byte]*FileTransfer{},
 378                 RemoteAddr: remoteAddr,
 379         }
 380         clientConn.transfers = map[int]map[[4]byte]*FileTransfer{
 381                 FileDownload:   {},
 382                 FileUpload:     {},
 383                 FolderDownload: {},
 384                 FolderUpload:   {},
 385                 bannerDownload: {},
 386         }
 387
 388         *s.NextGuestID++
 389         ID := *s.NextGuestID
 390
 391         binary.BigEndian.PutUint16(*clientConn.ID, ID)
 392         s.Clients[ID] = clientConn
 393
 394         return clientConn
 395 }
 396
 397 // NewUser creates a new user account entry in the server map and config file
 398 func (s *Server) NewUser(login, name, password string, access accessBitmap) error {
 399         s.mux.Lock()
 400         defer s.mux.Unlock()
 401
 402         account := Account{
 403                 Login:    login,
 404                 Name:     name,
 405                 Password: hashAndSalt([]byte(password)),
 406                 Access:   access,
 407         }
 408         out, err := yaml.Marshal(&account)
 409         if err != nil {
 410                 return err
 411         }
 412         s.Accounts[login] = &account
 413
 414         return s.FS.WriteFile(filepath.Join(s.ConfigDir, "Users", login+".yaml"), out, 0666)
 415 }
 416
 417 func (s *Server) UpdateUser(login, newLogin, name, password string, access accessBitmap) error {
 418         s.mux.Lock()
 419         defer s.mux.Unlock()
 420
 421         // update renames the user login
 422         if login != newLogin {
 423                 err := os.Rename(filepath.Join(s.ConfigDir, "Users", login+".yaml"), filepath.Join(s.ConfigDir, "Users", newLogin+".yaml"))
 424                 if err != nil {
 425                         return err
 426                 }
 427                 s.Accounts[newLogin] = s.Accounts[login]
 428                 delete(s.Accounts, login)
 429         }
 430
 431         account := s.Accounts[newLogin]
 432         account.Access = access
 433         account.Name = name
 434         account.Password = password
 435
 436         out, err := yaml.Marshal(&account)
 437         if err != nil {
 438                 return err
 439         }
 440
 441         if err := os.WriteFile(filepath.Join(s.ConfigDir, "Users", newLogin+".yaml"), out, 0666); err != nil {
 442                 return err
 443         }
 444
 445         return nil
 446 }
 447
 448 // DeleteUser deletes the user account
 449 func (s *Server) DeleteUser(login string) error {
 450         s.mux.Lock()
 451         defer s.mux.Unlock()
 452
 453         delete(s.Accounts, login)
 454
 455         return s.FS.Remove(filepath.Join(s.ConfigDir, "Users", login+".yaml"))
 456 }
 457
 458 func (s *Server) connectedUsers() []Field {
 459         s.mux.Lock()
 460         defer s.mux.Unlock()
 461
 462         var connectedUsers []Field
 463         for _, c := range sortedClients(s.Clients) {
 464                 user := User{
 465                         ID:    *c.ID,
 466                         Icon:  c.Icon,
 467                         Flags: c.Flags,
 468                         Name:  string(c.UserName),
 469                 }
 470                 connectedUsers = append(connectedUsers, NewField(FieldUsernameWithInfo, user.Payload()))
 471         }
 472         return connectedUsers
 473 }
 474
 475 func (s *Server) loadBanList(path string) error {
 476         fh, err := os.Open(path)
 477         if err != nil {
 478                 return err
 479         }
 480         decoder := yaml.NewDecoder(fh)
 481
 482         return decoder.Decode(s.banList)
 483 }
 484
 485 // loadThreadedNews loads the threaded news data from disk
 486 func (s *Server) loadThreadedNews(threadedNewsPath string) error {
 487         fh, err := os.Open(threadedNewsPath)
 488         if err != nil {
 489                 return err
 490         }
 491         decoder := yaml.NewDecoder(fh)
 492
 493         return decoder.Decode(s.ThreadedNews)
 494 }
 495
 496 // loadAccounts loads account data from disk
 497 func (s *Server) loadAccounts(userDir string) error {
 498         matches, err := filepath.Glob(filepath.Join(userDir, "*.yaml"))
 499         if err != nil {
 500                 return err
 501         }
 502
 503         if len(matches) == 0 {
 504                 return errors.New("no user accounts found in " + userDir)
 505         }
 506
 507         for _, file := range matches {
 508                 fh, err := s.FS.Open(file)
 509                 if err != nil {
 510                         return err
 511                 }
 512
 513                 account := Account{}
 514                 decoder := yaml.NewDecoder(fh)
 515                 if err := decoder.Decode(&account); err != nil {
 516                         return err
 517                 }
 518
 519                 s.Accounts[account.Login] = &account
 520         }
 521         return nil
 522 }
 523
 524 func (s *Server) loadConfig(path string) error {
 525         fh, err := s.FS.Open(path)
 526         if err != nil {
 527                 return err
 528         }
 529
 530         decoder := yaml.NewDecoder(fh)
 531         err = decoder.Decode(s.Config)
 532         if err != nil {
 533                 return err
 534         }
 535
 536         validate := validator.New()
 537         err = validate.Struct(s.Config)
 538         if err != nil {
 539                 return err
 540         }
 541         return nil
 542 }
 543
 544 // handleNewConnection takes a new net.Conn and performs the initial login sequence
 545 func (s *Server) handleNewConnection(ctx context.Context, rwc io.ReadWriteCloser, remoteAddr string) error {
 546         defer dontPanic(s.Logger)
 547
 548         if err := Handshake(rwc); err != nil {
 549                 return err
 550         }
 551
 552         // Create a new scanner for parsing incoming bytes into transaction tokens
 553         scanner := bufio.NewScanner(rwc)
 554         scanner.Split(transactionScanner)
 555
 556         scanner.Scan()
 557
 558         // Make a new []byte slice and copy the scanner bytes to it.  This is critical to avoid a data race as the
 559         // scanner re-uses the buffer for subsequent scans.
 560         buf := make([]byte, len(scanner.Bytes()))
 561         copy(buf, scanner.Bytes())
 562
 563         var clientLogin Transaction
 564         if _, err := clientLogin.Write(buf); err != nil {
 565                 return err
 566         }
 567
 568         // check if remoteAddr is present in the ban list
 569         if banUntil, ok := s.banList[strings.Split(remoteAddr, ":")[0]]; ok {
 570                 // permaban
 571                 if banUntil == nil {
 572                         t := NewTransaction(
 573                                 TranServerMsg,
 574                                 &[]byte{0, 0},
 575                                 NewField(FieldData, []byte("You are permanently banned on this server")),
 576                                 NewField(FieldChatOptions, []byte{0, 0}),
 577                         )
 578
 579                         b, err := t.MarshalBinary()
 580                         if err != nil {
 581                                 return err
 582                         }
 583
 584                         _, err = rwc.Write(b)
 585                         if err != nil {
 586                                 return err
 587                         }
 588
 589                         time.Sleep(1 * time.Second)
 590                         return nil
 591                 }
 592
 593                 // temporary ban
 594                 if time.Now().Before(*banUntil) {
 595                         t := NewTransaction(
 596                                 TranServerMsg,
 597                                 &[]byte{0, 0},
 598                                 NewField(FieldData, []byte("You are temporarily banned on this server")),
 599                                 NewField(FieldChatOptions, []byte{0, 0}),
 600                         )
 601                         b, err := t.MarshalBinary()
 602                         if err != nil {
 603                                 return err
 604                         }
 605
 606                         _, err = rwc.Write(b)
 607                         if err != nil {
 608                                 return err
 609                         }
 610
 611                         time.Sleep(1 * time.Second)
 612                         return nil
 613                 }
 614         }
 615
 616         c := s.NewClientConn(rwc, remoteAddr)
 617         defer c.Disconnect()
 618
 619         encodedLogin := clientLogin.GetField(FieldUserLogin).Data
 620         encodedPassword := clientLogin.GetField(FieldUserPassword).Data
 621         c.Version = clientLogin.GetField(FieldVersion).Data
 622
 623         var login string
 624         for _, char := range encodedLogin {
 625                 login += string(rune(255 - uint(char)))
 626         }
 627         if login == "" {
 628                 login = GuestAccount
 629         }
 630
 631         c.logger = s.Logger.With("remoteAddr", remoteAddr, "login", login)
 632
 633         // If authentication fails, send error reply and close connection
 634         if !c.Authenticate(login, encodedPassword) {
 635                 t := c.NewErrReply(&clientLogin, "Incorrect login.")
 636                 b, err := t.MarshalBinary()
 637                 if err != nil {
 638                         return err
 639                 }
 640                 if _, err := rwc.Write(b); err != nil {
 641                         return err
 642                 }
 643
 644                 c.logger.Infow("Login failed", "clientVersion", fmt.Sprintf("%x", c.Version))
 645
 646                 return nil
 647         }
 648
 649         if clientLogin.GetField(FieldUserIconID).Data != nil {
 650                 c.Icon = clientLogin.GetField(FieldUserIconID).Data
 651         }
 652
 653         c.Account = c.Server.Accounts[login]
 654
 655         if clientLogin.GetField(FieldUserName).Data != nil {
 656                 if c.Authorize(accessAnyName) {
 657                         c.UserName = clientLogin.GetField(FieldUserName).Data
 658                 } else {
 659                         c.UserName = []byte(c.Account.Name)
 660                 }
 661         }
 662
 663         if c.Authorize(accessDisconUser) {
 664                 c.Flags = []byte{0, 2}
 665         }
 666
 667         s.outbox <- c.NewReply(&clientLogin,
 668                 NewField(FieldVersion, []byte{0x00, 0xbe}),
 669                 NewField(FieldCommunityBannerID, []byte{0, 0}),
 670                 NewField(FieldServerName, []byte(s.Config.Name)),
 671         )
 672
 673         // Send user access privs so client UI knows how to behave
 674         c.Server.outbox <- *NewTransaction(TranUserAccess, c.ID, NewField(FieldUserAccess, c.Account.Access[:]))
 675
 676         // Accounts with accessNoAgreement do not receive the server agreement on login.  The behavior is different between
 677         // client versions.  For 1.2.3 client, we do not send TranShowAgreement.  For other client versions, we send
 678         // TranShowAgreement but with the NoServerAgreement field set to 1.
 679         if c.Authorize(accessNoAgreement) {
 680                 // If client version is nil, then the client uses the 1.2.3 login behavior
 681                 if c.Version != nil {
 682                         c.Server.outbox <- *NewTransaction(TranShowAgreement, c.ID, NewField(FieldNoServerAgreement, []byte{1}))
 683                 }
 684         } else {
 685                 c.Server.outbox <- *NewTransaction(TranShowAgreement, c.ID, NewField(FieldData, s.Agreement))
 686         }
 687
 688         // If the client has provided a username as part of the login, we can infer that it is using the 1.2.3 login
 689         // flow and not the 1.5+ flow.
 690         if len(c.UserName) != 0 {
 691                 // Add the client username to the logger.  For 1.5+ clients, we don't have this information yet as it comes as
 692                 // part of TranAgreed
 693                 c.logger = c.logger.With("name", string(c.UserName))
 694
 695                 c.logger.Infow("Login successful", "clientVersion", "Not sent (probably 1.2.3)")
 696
 697                 // Notify other clients on the server that the new user has logged in.  For 1.5+ clients we don't have this
 698                 // information yet, so we do it in TranAgreed instead
 699                 for _, t := range c.notifyOthers(
 700                         *NewTransaction(
 701                                 TranNotifyChangeUser, nil,
 702                                 NewField(FieldUserName, c.UserName),
 703                                 NewField(FieldUserID, *c.ID),
 704                                 NewField(FieldUserIconID, c.Icon),
 705                                 NewField(FieldUserFlags, c.Flags),
 706                         ),
 707                 ) {
 708                         c.Server.outbox <- t
 709                 }
 710         }
 711
 712         c.Server.Stats.ConnectionCounter += 1
 713         if len(s.Clients) > c.Server.Stats.ConnectionPeak {
 714                 c.Server.Stats.ConnectionPeak = len(s.Clients)
 715         }
 716
 717         // Scan for new transactions and handle them as they come in.
 718         for scanner.Scan() {
 719                 // Make a new []byte slice and copy the scanner bytes to it.  This is critical to avoid a data race as the
 720                 // scanner re-uses the buffer for subsequent scans.
 721                 buf := make([]byte, len(scanner.Bytes()))
 722                 copy(buf, scanner.Bytes())
 723
 724                 var t Transaction
 725                 if _, err := t.Write(buf); err != nil {
 726                         return err
 727                 }
 728
 729                 if err := c.handleTransaction(t); err != nil {
 730                         c.logger.Errorw("Error handling transaction", "err", err)
 731                 }
 732         }
 733         return nil
 734 }
 735
 736 func (s *Server) NewPrivateChat(cc *ClientConn) []byte {
 737         s.PrivateChatsMu.Lock()
 738         defer s.PrivateChatsMu.Unlock()
 739
 740         randID := make([]byte, 4)
 741         rand.Read(randID)
 742         data := binary.BigEndian.Uint32(randID)
 743
 744         s.PrivateChats[data] = &PrivateChat{
 745                 ClientConn: make(map[uint16]*ClientConn),
 746         }
 747         s.PrivateChats[data].ClientConn[cc.uint16ID()] = cc
 748
 749         return randID
 750 }
 751
 752 const dlFldrActionSendFile = 1
 753 const dlFldrActionResumeFile = 2
 754 const dlFldrActionNextFile = 3
 755
 756 // handleFileTransfer receives a client net.Conn from the file transfer server, performs the requested transfer type, then closes the connection
 757 func (s *Server) handleFileTransfer(ctx context.Context, rwc io.ReadWriter) error {
 758         defer dontPanic(s.Logger)
 759
 760         txBuf := make([]byte, 16)
 761         if _, err := io.ReadFull(rwc, txBuf); err != nil {
 762                 return err
 763         }
 764
 765         var t transfer
 766         if _, err := t.Write(txBuf); err != nil {
 767                 return err
 768         }
 769
 770         defer func() {
 771                 s.mux.Lock()
 772                 delete(s.fileTransfers, t.ReferenceNumber)
 773                 s.mux.Unlock()
 774
 775                 // Wait a few seconds before closing the connection: this is a workaround for problems
 776                 // observed with Windows clients where the client must initiate close of the TCP connection before
 777                 // the server does.  This is gross and seems unnecessary.  TODO: Revisit?
 778                 time.Sleep(3 * time.Second)
 779         }()
 780
 781         s.mux.Lock()
 782         fileTransfer, ok := s.fileTransfers[t.ReferenceNumber]
 783         s.mux.Unlock()
 784         if !ok {
 785                 return errors.New("invalid transaction ID")
 786         }
 787
 788         defer func() {
 789                 fileTransfer.ClientConn.transfersMU.Lock()
 790                 delete(fileTransfer.ClientConn.transfers[fileTransfer.Type], t.ReferenceNumber)
 791                 fileTransfer.ClientConn.transfersMU.Unlock()
 792         }()
 793
 794         rLogger := s.Logger.With(
 795                 "remoteAddr", ctx.Value(contextKeyReq).(requestCtx).remoteAddr,
 796                 "login", fileTransfer.ClientConn.Account.Login,
 797                 "name", string(fileTransfer.ClientConn.UserName),
 798         )
 799
 800         fullPath, err := readPath(s.Config.FileRoot, fileTransfer.FilePath, fileTransfer.FileName)
 801         if err != nil {
 802                 return err
 803         }
 804
 805         switch fileTransfer.Type {
 806         case bannerDownload:
 807                 if err := s.bannerDownload(rwc); err != nil {
 808                         return err
 809                 }
 810         case FileDownload:
 811                 s.Stats.DownloadCounter += 1
 812                 s.Stats.DownloadsInProgress += 1
 813                 defer func() {
 814                         s.Stats.DownloadsInProgress -= 1
 815                 }()
 816
 817                 var dataOffset int64
 818                 if fileTransfer.fileResumeData != nil {
 819                         dataOffset = int64(binary.BigEndian.Uint32(fileTransfer.fileResumeData.ForkInfoList[0].DataSize[:]))
 820                 }
 821
 822                 fw, err := newFileWrapper(s.FS, fullPath, 0)
 823                 if err != nil {
 824                         return err
 825                 }
 826
 827                 rLogger.Infow("File download started", "filePath", fullPath)
 828
 829                 // if file transfer options are included, that means this is a "quick preview" request from a 1.5+ client
 830                 if fileTransfer.options == nil {
 831                         // Start by sending flat file object to client
 832                         if _, err := rwc.Write(fw.ffo.BinaryMarshal()); err != nil {
 833                                 return err
 834                         }
 835                 }
 836
 837                 file, err := fw.dataForkReader()
 838                 if err != nil {
 839                         return err
 840                 }
 841
 842                 br := bufio.NewReader(file)
 843                 if _, err := br.Discard(int(dataOffset)); err != nil {
 844                         return err
 845                 }
 846
 847                 if _, err = io.Copy(rwc, io.TeeReader(br, fileTransfer.bytesSentCounter)); err != nil {
 848                         return err
 849                 }
 850
 851                 // if the client requested to resume transfer, do not send the resource fork header, or it will be appended into the fileWrapper data
 852                 if fileTransfer.fileResumeData == nil {
 853                         err = binary.Write(rwc, binary.BigEndian, fw.rsrcForkHeader())
 854                         if err != nil {
 855                                 return err
 856                         }
 857                 }
 858
 859                 rFile, err := fw.rsrcForkFile()
 860                 if err != nil {
 861                         return nil
 862                 }
 863
 864                 if _, err = io.Copy(rwc, io.TeeReader(rFile, fileTransfer.bytesSentCounter)); err != nil {
 865                         return err
 866                 }
 867
 868         case FileUpload:
 869                 s.Stats.UploadCounter += 1
 870                 s.Stats.UploadsInProgress += 1
 871                 defer func() { s.Stats.UploadsInProgress -= 1 }()
 872
 873                 var file *os.File
 874
 875                 // A file upload has three possible cases:
 876                 // 1) Upload a new file
 877                 // 2) Resume a partially transferred file
 878                 // 3) Replace a fully uploaded file
 879                 //  We have to infer which case applies by inspecting what is already on the filesystem
 880
 881                 // 1) Check for existing file:
 882                 _, err = os.Stat(fullPath)
 883                 if err == nil {
 884                         return errors.New("existing file found at " + fullPath)
 885                 }
 886                 if errors.Is(err, fs.ErrNotExist) {
 887                         // If not found, open or create a new .incomplete file
 888                         file, err = os.OpenFile(fullPath+incompleteFileSuffix, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0644)
 889                         if err != nil {
 890                                 return err
 891                         }
 892                 }
 893
 894                 f, err := newFileWrapper(s.FS, fullPath, 0)
 895                 if err != nil {
 896                         return err
 897                 }
 898
 899                 rLogger.Infow("File upload started", "dstFile", fullPath)
 900
 901                 rForkWriter := io.Discard
 902                 iForkWriter := io.Discard
 903                 if s.Config.PreserveResourceForks {
 904                         rForkWriter, err = f.rsrcForkWriter()
 905                         if err != nil {
 906                                 return err
 907                         }
 908
 909                         iForkWriter, err = f.infoForkWriter()
 910                         if err != nil {
 911                                 return err
 912                         }
 913                 }
 914
 915                 if err := receiveFile(rwc, file, rForkWriter, iForkWriter, fileTransfer.bytesSentCounter); err != nil {
 916                         s.Logger.Error(err)
 917                 }
 918
 919                 if err := file.Close(); err != nil {
 920                         return err
 921                 }
 922
 923                 if err := s.FS.Rename(fullPath+".incomplete", fullPath); err != nil {
 924                         return err
 925                 }
 926
 927                 rLogger.Infow("File upload complete", "dstFile", fullPath)
 928
 929         case FolderDownload:
 930                 s.Stats.DownloadCounter += 1
 931                 s.Stats.DownloadsInProgress += 1
 932                 defer func() { s.Stats.DownloadsInProgress -= 1 }()
 933
 934                 // Folder Download flow:
 935                 // 1. Get filePath from the transfer
 936                 // 2. Iterate over files
 937                 // 3. For each fileWrapper:
 938                 //       Send fileWrapper header to client
 939                 // The client can reply in 3 ways:
 940                 //
 941                 // 1. If type is an odd number (unknown type?), or fileWrapper download for the current fileWrapper is completed:
 942                 //              client sends []byte{0x00, 0x03} to tell the server to continue to the next fileWrapper
 943                 //
 944                 // 2. If download of a fileWrapper is to be resumed:
 945                 //              client sends:
 946                 //                      []byte{0x00, 0x02} // download folder action
 947                 //                      [2]byte // Resume data size
 948                 //                      []byte fileWrapper resume data (see myField_FileResumeData)
 949                 //
 950                 // 3. Otherwise, download of the fileWrapper is requested and client sends []byte{0x00, 0x01}
 951                 //
 952                 // When download is requested (case 2 or 3), server replies with:
 953                 //                      [4]byte - fileWrapper size
 954                 //                      []byte  - Flattened File Object
 955                 //
 956                 // After every fileWrapper download, client could request next fileWrapper with:
 957                 //                      []byte{0x00, 0x03}
 958                 //
 959                 // This notifies the server to send the next item header
 960
 961                 basePathLen := len(fullPath)
 962
 963                 rLogger.Infow("Start folder download", "path", fullPath)
 964
 965                 nextAction := make([]byte, 2)
 966                 if _, err := io.ReadFull(rwc, nextAction); err != nil {
 967                         return err
 968                 }
 969
 970                 i := 0
 971                 err = filepath.Walk(fullPath+"/", func(path string, info os.FileInfo, err error) error {
 972                         s.Stats.DownloadCounter += 1
 973                         i += 1
 974
 975                         if err != nil {
 976                                 return err
 977                         }
 978
 979                         // skip dot files
 980                         if strings.HasPrefix(info.Name(), ".") {
 981                                 return nil
 982                         }
 983
 984                         hlFile, err := newFileWrapper(s.FS, path, 0)
 985                         if err != nil {
 986                                 return err
 987                         }
 988
 989                         subPath := path[basePathLen+1:]
 990                         rLogger.Debugw("Sending fileheader", "i", i, "path", path, "fullFilePath", fullPath, "subPath", subPath, "IsDir", info.IsDir())
 991
 992                         if i == 1 {
 993                                 return nil
 994                         }
 995
 996                         fileHeader := NewFileHeader(subPath, info.IsDir())
 997
 998                         // Send the fileWrapper header to client
 999                         if _, err := rwc.Write(fileHeader.Payload()); err != nil {
1000                                 s.Logger.Errorf("error sending file header: %v", err)
1001                                 return err
1002                         }
1003
1004                         // Read the client's Next Action request
1005                         if _, err := io.ReadFull(rwc, nextAction); err != nil {
1006                                 return err
1007                         }
1008
1009                         rLogger.Debugw("Client folder download action", "action", fmt.Sprintf("%X", nextAction[0:2]))
1010
1011                         var dataOffset int64
1012
1013                         switch nextAction[1] {
1014                         case dlFldrActionResumeFile:
1015                                 // get size of resumeData
1016                                 resumeDataByteLen := make([]byte, 2)
1017                                 if _, err := io.ReadFull(rwc, resumeDataByteLen); err != nil {
1018                                         return err
1019                                 }
1020
1021                                 resumeDataLen := binary.BigEndian.Uint16(resumeDataByteLen)
1022                                 resumeDataBytes := make([]byte, resumeDataLen)
1023                                 if _, err := io.ReadFull(rwc, resumeDataBytes); err != nil {
1024                                         return err
1025                                 }
1026
1027                                 var frd FileResumeData
1028                                 if err := frd.UnmarshalBinary(resumeDataBytes); err != nil {
1029                                         return err
1030                                 }
1031                                 dataOffset = int64(binary.BigEndian.Uint32(frd.ForkInfoList[0].DataSize[:]))
1032                         case dlFldrActionNextFile:
1033                                 // client asked to skip this file
1034                                 return nil
1035                         }
1036
1037                         if info.IsDir() {
1038                                 return nil
1039                         }
1040
1041                         rLogger.Infow("File download started",
1042                                 "fileName", info.Name(),
1043                                 "TransferSize", fmt.Sprintf("%x", hlFile.ffo.TransferSize(dataOffset)),
1044                         )
1045
1046                         // Send file size to client
1047                         if _, err := rwc.Write(hlFile.ffo.TransferSize(dataOffset)); err != nil {
1048                                 s.Logger.Error(err)
1049                                 return err
1050                         }
1051
1052                         // Send ffo bytes to client
1053                         if _, err := rwc.Write(hlFile.ffo.BinaryMarshal()); err != nil {
1054                                 s.Logger.Error(err)
1055                                 return err
1056                         }
1057
1058                         file, err := s.FS.Open(path)
1059                         if err != nil {
1060                                 return err
1061                         }
1062
1063                         // wr := bufio.NewWriterSize(rwc, 1460)
1064                         if _, err = io.Copy(rwc, io.TeeReader(file, fileTransfer.bytesSentCounter)); err != nil {
1065                                 return err
1066                         }
1067
1068                         if nextAction[1] != 2 && hlFile.ffo.FlatFileHeader.ForkCount[1] == 3 {
1069                                 err = binary.Write(rwc, binary.BigEndian, hlFile.rsrcForkHeader())
1070                                 if err != nil {
1071                                         return err
1072                                 }
1073
1074                                 rFile, err := hlFile.rsrcForkFile()
1075                                 if err != nil {
1076                                         return err
1077                                 }
1078
1079                                 if _, err = io.Copy(rwc, io.TeeReader(rFile, fileTransfer.bytesSentCounter)); err != nil {
1080                                         return err
1081                                 }
1082                         }
1083
1084                         // Read the client's Next Action request.  This is always 3, I think?
1085                         if _, err := io.ReadFull(rwc, nextAction); err != nil {
1086                                 return err
1087                         }
1088
1089                         return nil
1090                 })
1091
1092                 if err != nil {
1093                         return err
1094                 }
1095
1096         case FolderUpload:
1097                 s.Stats.UploadCounter += 1
1098                 s.Stats.UploadsInProgress += 1
1099                 defer func() { s.Stats.UploadsInProgress -= 1 }()
1100                 rLogger.Infow(
1101                         "Folder upload started",
1102                         "dstPath", fullPath,
1103                         "TransferSize", binary.BigEndian.Uint32(fileTransfer.TransferSize),
1104                         "FolderItemCount", fileTransfer.FolderItemCount,
1105                 )
1106
1107                 // Check if the target folder exists.  If not, create it.
1108                 if _, err := s.FS.Stat(fullPath); os.IsNotExist(err) {
1109                         if err := s.FS.Mkdir(fullPath, 0777); err != nil {
1110                                 return err
1111                         }
1112                 }
1113
1114                 // Begin the folder upload flow by sending the "next file action" to client
1115                 if _, err := rwc.Write([]byte{0, dlFldrActionNextFile}); err != nil {
1116                         return err
1117                 }
1118
1119                 fileSize := make([]byte, 4)
1120
1121                 for i := 0; i < fileTransfer.ItemCount(); i++ {
1122                         s.Stats.UploadCounter += 1
1123
1124                         var fu folderUpload
1125                         if _, err := io.ReadFull(rwc, fu.DataSize[:]); err != nil {
1126                                 return err
1127                         }
1128                         if _, err := io.ReadFull(rwc, fu.IsFolder[:]); err != nil {
1129                                 return err
1130                         }
1131                         if _, err := io.ReadFull(rwc, fu.PathItemCount[:]); err != nil {
1132                                 return err
1133                         }
1134
1135                         fu.FileNamePath = make([]byte, binary.BigEndian.Uint16(fu.DataSize[:])-4) // -4 to subtract the path separator bytes
1136
1137                         if _, err := io.ReadFull(rwc, fu.FileNamePath); err != nil {
1138                                 return err
1139                         }
1140
1141                         rLogger.Infow(
1142                                 "Folder upload continued",
1143                                 "FormattedPath", fu.FormattedPath(),
1144                                 "IsFolder", fmt.Sprintf("%x", fu.IsFolder),
1145                                 "PathItemCount", binary.BigEndian.Uint16(fu.PathItemCount[:]),
1146                         )
1147
1148                         if fu.IsFolder == [2]byte{0, 1} {
1149                                 if _, err := os.Stat(filepath.Join(fullPath, fu.FormattedPath())); os.IsNotExist(err) {
1150                                         if err := os.Mkdir(filepath.Join(fullPath, fu.FormattedPath()), 0777); err != nil {
1151                                                 return err
1152                                         }
1153                                 }
1154
1155                                 // Tell client to send next file
1156                                 if _, err := rwc.Write([]byte{0, dlFldrActionNextFile}); err != nil {
1157                                         return err
1158                                 }
1159                         } else {
1160                                 nextAction := dlFldrActionSendFile
1161
1162                                 // Check if we have the full file already.  If so, send dlFldrAction_NextFile to client to skip.
1163                                 _, err = os.Stat(filepath.Join(fullPath, fu.FormattedPath()))
1164                                 if err != nil && !errors.Is(err, fs.ErrNotExist) {
1165                                         return err
1166                                 }
1167                                 if err == nil {
1168                                         nextAction = dlFldrActionNextFile
1169                                 }
1170
1171                                 //  Check if we have a partial file already.  If so, send dlFldrAction_ResumeFile to client to resume upload.
1172                                 incompleteFile, err := os.Stat(filepath.Join(fullPath, fu.FormattedPath()+incompleteFileSuffix))
1173                                 if err != nil && !errors.Is(err, fs.ErrNotExist) {
1174                                         return err
1175                                 }
1176                                 if err == nil {
1177                                         nextAction = dlFldrActionResumeFile
1178                                 }
1179
1180                                 if _, err := rwc.Write([]byte{0, uint8(nextAction)}); err != nil {
1181                                         return err
1182                                 }
1183
1184                                 switch nextAction {
1185                                 case dlFldrActionNextFile:
1186                                         continue
1187                                 case dlFldrActionResumeFile:
1188                                         offset := make([]byte, 4)
1189                                         binary.BigEndian.PutUint32(offset, uint32(incompleteFile.Size()))
1190
1191                                         file, err := os.OpenFile(fullPath+"/"+fu.FormattedPath()+incompleteFileSuffix, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
1192                                         if err != nil {
1193                                                 return err
1194                                         }
1195
1196                                         fileResumeData := NewFileResumeData([]ForkInfoList{*NewForkInfoList(offset)})
1197
1198                                         b, _ := fileResumeData.BinaryMarshal()
1199
1200                                         bs := make([]byte, 2)
1201                                         binary.BigEndian.PutUint16(bs, uint16(len(b)))
1202
1203                                         if _, err := rwc.Write(append(bs, b...)); err != nil {
1204                                                 return err
1205                                         }
1206
1207                                         if _, err := io.ReadFull(rwc, fileSize); err != nil {
1208                                                 return err
1209                                         }
1210
1211                                         if err := receiveFile(rwc, file, io.Discard, io.Discard, fileTransfer.bytesSentCounter); err != nil {
1212                                                 s.Logger.Error(err)
1213                                         }
1214
1215                                         err = os.Rename(fullPath+"/"+fu.FormattedPath()+".incomplete", fullPath+"/"+fu.FormattedPath())
1216                                         if err != nil {
1217                                                 return err
1218                                         }
1219
1220                                 case dlFldrActionSendFile:
1221                                         if _, err := io.ReadFull(rwc, fileSize); err != nil {
1222                                                 return err
1223                                         }
1224
1225                                         filePath := filepath.Join(fullPath, fu.FormattedPath())
1226
1227                                         hlFile, err := newFileWrapper(s.FS, filePath, 0)
1228                                         if err != nil {
1229                                                 return err
1230                                         }
1231
1232                                         rLogger.Infow("Starting file transfer", "path", filePath, "fileNum", i+1, "fileSize", binary.BigEndian.Uint32(fileSize))
1233
1234                                         incWriter, err := hlFile.incFileWriter()
1235                                         if err != nil {
1236                                                 return err
1237                                         }
1238
1239                                         rForkWriter := io.Discard
1240                                         iForkWriter := io.Discard
1241                                         if s.Config.PreserveResourceForks {
1242                                                 iForkWriter, err = hlFile.infoForkWriter()
1243                                                 if err != nil {
1244                                                         return err
1245                                                 }
1246
1247                                                 rForkWriter, err = hlFile.rsrcForkWriter()
1248                                                 if err != nil {
1249                                                         return err
1250                                                 }
1251                                         }
1252                                         if err := receiveFile(rwc, incWriter, rForkWriter, iForkWriter, fileTransfer.bytesSentCounter); err != nil {
1253                                                 return err
1254                                         }
1255
1256                                         if err := os.Rename(filePath+".incomplete", filePath); err != nil {
1257                                                 return err
1258                                         }
1259                                 }
1260
1261                                 // Tell client to send next fileWrapper
1262                                 if _, err := rwc.Write([]byte{0, dlFldrActionNextFile}); err != nil {
1263                                         return err
1264                                 }
1265                         }
1266                 }
1267                 rLogger.Infof("Folder upload complete")
1268         }
1269
1270         return nil
1271 }