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
 111                 s.Logger.Fatal(s.ServeFileTransfers(ctx, ln))
 112         }()
 113
 114         wg.Wait()
 115
 116         return nil
 117 }
 118
 119 func (s *Server) ServeFileTransfers(ctx context.Context, ln net.Listener) error {
 120         for {
 121                 conn, err := ln.Accept()
 122                 if err != nil {
 123                         return err
 124                 }
 125
 126                 go func() {
 127                         defer func() { _ = conn.Close() }()
 128
 129                         err = s.handleFileTransfer(
 130                                 context.WithValue(ctx, contextKeyReq, requestCtx{
 131                                         remoteAddr: conn.RemoteAddr().String(),
 132                                 }),
 133                                 conn,
 134                         )
 135
 136                         if err != nil {
 137                                 s.Logger.Errorw("file transfer error", "reason", err)
 138                         }
 139                 }()
 140         }
 141 }
 142
 143 func (s *Server) sendTransaction(t Transaction) error {
 144         clientID, err := byteToInt(*t.clientID)
 145         if err != nil {
 146                 return err
 147         }
 148
 149         s.mux.Lock()
 150         client := s.Clients[uint16(clientID)]
 151         s.mux.Unlock()
 152         if client == nil {
 153                 return fmt.Errorf("invalid client id %v", *t.clientID)
 154         }
 155
 156         b, err := t.MarshalBinary()
 157         if err != nil {
 158                 return err
 159         }
 160
 161         _, err = client.Connection.Write(b)
 162         if err != nil {
 163                 return err
 164         }
 165
 166         return nil
 167 }
 168
 169 func (s *Server) processOutbox() {
 170         for {
 171                 t := <-s.outbox
 172                 go func() {
 173                         if err := s.sendTransaction(t); err != nil {
 174                                 s.Logger.Errorw("error sending transaction", "err", err)
 175                         }
 176                 }()
 177         }
 178 }
 179
 180 func (s *Server) Serve(ctx context.Context, ln net.Listener) error {
 181         go s.processOutbox()
 182
 183         for {
 184                 conn, err := ln.Accept()
 185                 if err != nil {
 186                         s.Logger.Errorw("error accepting connection", "err", err)
 187                 }
 188                 connCtx := context.WithValue(ctx, contextKeyReq, requestCtx{
 189                         remoteAddr: conn.RemoteAddr().String(),
 190                 })
 191
 192                 go func() {
 193                         s.Logger.Infow("Connection established", "RemoteAddr", conn.RemoteAddr())
 194
 195                         defer conn.Close()
 196                         if err := s.handleNewConnection(connCtx, conn, conn.RemoteAddr().String()); err != nil {
 197                                 if err == io.EOF {
 198                                         s.Logger.Infow("Client disconnected", "RemoteAddr", conn.RemoteAddr())
 199                                 } else {
 200                                         s.Logger.Errorw("error serving request", "RemoteAddr", conn.RemoteAddr(), "err", err)
 201                                 }
 202                         }
 203                 }()
 204         }
 205 }
 206
 207 const (
 208         agreementFile = "Agreement.txt"
 209 )
 210
 211 // NewServer constructs a new Server from a config dir
 212 func NewServer(configDir string, netPort int, logger *zap.SugaredLogger, FS FileStore) (*Server, error) {
 213         server := Server{
 214                 Port:          netPort,
 215                 Accounts:      make(map[string]*Account),
 216                 Config:        new(Config),
 217                 Clients:       make(map[uint16]*ClientConn),
 218                 fileTransfers: make(map[[4]byte]*FileTransfer),
 219                 PrivateChats:  make(map[uint32]*PrivateChat),
 220                 ConfigDir:     configDir,
 221                 Logger:        logger,
 222                 NextGuestID:   new(uint16),
 223                 outbox:        make(chan Transaction),
 224                 Stats:         &Stats{Since: time.Now()},
 225                 ThreadedNews:  &ThreadedNews{},
 226                 FS:            FS,
 227                 banList:       make(map[string]*time.Time),
 228         }
 229
 230         var err error
 231
 232         // generate a new random passID for tracker registration
 233         if _, err := rand.Read(server.TrackerPassID[:]); err != nil {
 234                 return nil, err
 235         }
 236
 237         server.Agreement, err = os.ReadFile(filepath.Join(configDir, agreementFile))
 238         if err != nil {
 239                 return nil, err
 240         }
 241
 242         if server.FlatNews, err = os.ReadFile(filepath.Join(configDir, "MessageBoard.txt")); err != nil {
 243                 return nil, err
 244         }
 245
 246         // try to load the ban list, but ignore errors as this file may not be present or may be empty
 247         _ = server.loadBanList(filepath.Join(configDir, "Banlist.yaml"))
 248
 249         if err := server.loadThreadedNews(filepath.Join(configDir, "ThreadedNews.yaml")); err != nil {
 250                 return nil, err
 251         }
 252
 253         if err := server.loadConfig(filepath.Join(configDir, "config.yaml")); err != nil {
 254                 return nil, err
 255         }
 256
 257         if err := server.loadAccounts(filepath.Join(configDir, "Users/")); err != nil {
 258                 return nil, err
 259         }
 260
 261         server.Config.FileRoot = filepath.Join(configDir, "Files")
 262
 263         *server.NextGuestID = 1
 264
 265         if server.Config.EnableTrackerRegistration {
 266                 server.Logger.Infow(
 267                         "Tracker registration enabled",
 268                         "frequency", fmt.Sprintf("%vs", trackerUpdateFrequency),
 269                         "trackers", server.Config.Trackers,
 270                 )
 271
 272                 go func() {
 273                         for {
 274                                 tr := &TrackerRegistration{
 275                                         UserCount:   server.userCount(),
 276                                         PassID:      server.TrackerPassID[:],
 277                                         Name:        server.Config.Name,
 278                                         Description: server.Config.Description,
 279                                 }
 280                                 binary.BigEndian.PutUint16(tr.Port[:], uint16(server.Port))
 281                                 for _, t := range server.Config.Trackers {
 282                                         if err := register(t, tr); err != nil {
 283                                                 server.Logger.Errorw("unable to register with tracker %v", "error", err)
 284                                         }
 285                                         server.Logger.Debugw("Sent Tracker registration", "addr", t)
 286                                 }
 287
 288                                 time.Sleep(trackerUpdateFrequency * time.Second)
 289                         }
 290                 }()
 291         }
 292
 293         // Start Client Keepalive go routine
 294         go server.keepaliveHandler()
 295
 296         return &server, nil
 297 }
 298
 299 func (s *Server) userCount() int {
 300         s.mux.Lock()
 301         defer s.mux.Unlock()
 302
 303         return len(s.Clients)
 304 }
 305
 306 func (s *Server) keepaliveHandler() {
 307         for {
 308                 time.Sleep(idleCheckInterval * time.Second)
 309                 s.mux.Lock()
 310
 311                 for _, c := range s.Clients {
 312                         c.IdleTime += idleCheckInterval
 313                         if c.IdleTime > userIdleSeconds && !c.Idle {
 314                                 c.Idle = true
 315
 316                                 flagBitmap := big.NewInt(int64(binary.BigEndian.Uint16(c.Flags)))
 317                                 flagBitmap.SetBit(flagBitmap, userFlagAway, 1)
 318                                 binary.BigEndian.PutUint16(c.Flags, uint16(flagBitmap.Int64()))
 319
 320                                 c.sendAll(
 321                                         TranNotifyChangeUser,
 322                                         NewField(FieldUserID, *c.ID),
 323                                         NewField(FieldUserFlags, c.Flags),
 324                                         NewField(FieldUserName, c.UserName),
 325                                         NewField(FieldUserIconID, c.Icon),
 326                                 )
 327                         }
 328                 }
 329                 s.mux.Unlock()
 330         }
 331 }
 332
 333 func (s *Server) writeBanList() error {
 334         s.banListMU.Lock()
 335         defer s.banListMU.Unlock()
 336
 337         out, err := yaml.Marshal(s.banList)
 338         if err != nil {
 339                 return err
 340         }
 341         err = os.WriteFile(
 342                 filepath.Join(s.ConfigDir, "Banlist.yaml"),
 343                 out,
 344                 0666,
 345         )
 346         return err
 347 }
 348
 349 func (s *Server) writeThreadedNews() error {
 350         s.threadedNewsMux.Lock()
 351         defer s.threadedNewsMux.Unlock()
 352
 353         out, err := yaml.Marshal(s.ThreadedNews)
 354         if err != nil {
 355                 return err
 356         }
 357         err = s.FS.WriteFile(
 358                 filepath.Join(s.ConfigDir, "ThreadedNews.yaml"),
 359                 out,
 360                 0666,
 361         )
 362         return err
 363 }
 364
 365 func (s *Server) NewClientConn(conn io.ReadWriteCloser, remoteAddr string) *ClientConn {
 366         s.mux.Lock()
 367         defer s.mux.Unlock()
 368
 369         clientConn := &ClientConn{
 370                 ID:         &[]byte{0, 0},
 371                 Icon:       []byte{0, 0},
 372                 Flags:      []byte{0, 0},
 373                 UserName:   []byte{},
 374                 Connection: conn,
 375                 Server:     s,
 376                 Version:    []byte{},
 377                 AutoReply:  []byte{},
 378                 transfers:  map[int]map[[4]byte]*FileTransfer{},
 379                 RemoteAddr: remoteAddr,
 380         }
 381         clientConn.transfers = map[int]map[[4]byte]*FileTransfer{
 382                 FileDownload:   {},
 383                 FileUpload:     {},
 384                 FolderDownload: {},
 385                 FolderUpload:   {},
 386                 bannerDownload: {},
 387         }
 388
 389         *s.NextGuestID++
 390         ID := *s.NextGuestID
 391
 392         binary.BigEndian.PutUint16(*clientConn.ID, ID)
 393         s.Clients[ID] = clientConn
 394
 395         return clientConn
 396 }
 397
 398 // NewUser creates a new user account entry in the server map and config file
 399 func (s *Server) NewUser(login, name, password string, access accessBitmap) error {
 400         s.mux.Lock()
 401         defer s.mux.Unlock()
 402
 403         account := Account{
 404                 Login:    login,
 405                 Name:     name,
 406                 Password: hashAndSalt([]byte(password)),
 407                 Access:   access,
 408         }
 409         out, err := yaml.Marshal(&account)
 410         if err != nil {
 411                 return err
 412         }
 413         s.Accounts[login] = &account
 414
 415         return s.FS.WriteFile(filepath.Join(s.ConfigDir, "Users", login+".yaml"), out, 0666)
 416 }
 417
 418 func (s *Server) UpdateUser(login, newLogin, name, password string, access accessBitmap) error {
 419         s.mux.Lock()
 420         defer s.mux.Unlock()
 421
 422         // update renames the user login
 423         if login != newLogin {
 424                 err := os.Rename(filepath.Join(s.ConfigDir, "Users", login+".yaml"), filepath.Join(s.ConfigDir, "Users", newLogin+".yaml"))
 425                 if err != nil {
 426                         return err
 427                 }
 428                 s.Accounts[newLogin] = s.Accounts[login]
 429                 delete(s.Accounts, login)
 430         }
 431
 432         account := s.Accounts[newLogin]
 433         account.Access = access
 434         account.Name = name
 435         account.Password = password
 436
 437         out, err := yaml.Marshal(&account)
 438         if err != nil {
 439                 return err
 440         }
 441
 442         if err := os.WriteFile(filepath.Join(s.ConfigDir, "Users", newLogin+".yaml"), out, 0666); err != nil {
 443                 return err
 444         }
 445
 446         return nil
 447 }
 448
 449 // DeleteUser deletes the user account
 450 func (s *Server) DeleteUser(login string) error {
 451         s.mux.Lock()
 452         defer s.mux.Unlock()
 453
 454         delete(s.Accounts, login)
 455
 456         return s.FS.Remove(filepath.Join(s.ConfigDir, "Users", login+".yaml"))
 457 }
 458
 459 func (s *Server) connectedUsers() []Field {
 460         s.mux.Lock()
 461         defer s.mux.Unlock()
 462
 463         var connectedUsers []Field
 464         for _, c := range sortedClients(s.Clients) {
 465                 user := User{
 466                         ID:    *c.ID,
 467                         Icon:  c.Icon,
 468                         Flags: c.Flags,
 469                         Name:  string(c.UserName),
 470                 }
 471                 connectedUsers = append(connectedUsers, NewField(FieldUsernameWithInfo, user.Payload()))
 472         }
 473         return connectedUsers
 474 }
 475
 476 func (s *Server) loadBanList(path string) error {
 477         fh, err := os.Open(path)
 478         if err != nil {
 479                 return err
 480         }
 481         decoder := yaml.NewDecoder(fh)
 482
 483         return decoder.Decode(s.banList)
 484 }
 485
 486 // loadThreadedNews loads the threaded news data from disk
 487 func (s *Server) loadThreadedNews(threadedNewsPath string) error {
 488         fh, err := os.Open(threadedNewsPath)
 489         if err != nil {
 490                 return err
 491         }
 492         decoder := yaml.NewDecoder(fh)
 493
 494         return decoder.Decode(s.ThreadedNews)
 495 }
 496
 497 // loadAccounts loads account data from disk
 498 func (s *Server) loadAccounts(userDir string) error {
 499         matches, err := filepath.Glob(filepath.Join(userDir, "*.yaml"))
 500         if err != nil {
 501                 return err
 502         }
 503
 504         if len(matches) == 0 {
 505                 return errors.New("no user accounts found in " + userDir)
 506         }
 507
 508         for _, file := range matches {
 509                 fh, err := s.FS.Open(file)
 510                 if err != nil {
 511                         return err
 512                 }
 513
 514                 account := Account{}
 515                 decoder := yaml.NewDecoder(fh)
 516                 if err := decoder.Decode(&account); err != nil {
 517                         return err
 518                 }
 519
 520                 s.Accounts[account.Login] = &account
 521         }
 522         return nil
 523 }
 524
 525 func (s *Server) loadConfig(path string) error {
 526         fh, err := s.FS.Open(path)
 527         if err != nil {
 528                 return err
 529         }
 530
 531         decoder := yaml.NewDecoder(fh)
 532         err = decoder.Decode(s.Config)
 533         if err != nil {
 534                 return err
 535         }
 536
 537         validate := validator.New()
 538         err = validate.Struct(s.Config)
 539         if err != nil {
 540                 return err
 541         }
 542         return nil
 543 }
 544
 545 // handleNewConnection takes a new net.Conn and performs the initial login sequence
 546 func (s *Server) handleNewConnection(ctx context.Context, rwc io.ReadWriteCloser, remoteAddr string) error {
 547         defer dontPanic(s.Logger)
 548
 549         if err := Handshake(rwc); err != nil {
 550                 return err
 551         }
 552
 553         // Create a new scanner for parsing incoming bytes into transaction tokens
 554         scanner := bufio.NewScanner(rwc)
 555         scanner.Split(transactionScanner)
 556
 557         scanner.Scan()
 558
 559         // Make a new []byte slice and copy the scanner bytes to it.  This is critical to avoid a data race as the
 560         // scanner re-uses the buffer for subsequent scans.
 561         buf := make([]byte, len(scanner.Bytes()))
 562         copy(buf, scanner.Bytes())
 563
 564         var clientLogin Transaction
 565         if _, err := clientLogin.Write(buf); err != nil {
 566                 return err
 567         }
 568
 569         // check if remoteAddr is present in the ban list
 570         if banUntil, ok := s.banList[strings.Split(remoteAddr, ":")[0]]; ok {
 571                 // permaban
 572                 if banUntil == nil {
 573                         t := NewTransaction(
 574                                 TranServerMsg,
 575                                 &[]byte{0, 0},
 576                                 NewField(FieldData, []byte("You are permanently banned on this server")),
 577                                 NewField(FieldChatOptions, []byte{0, 0}),
 578                         )
 579
 580                         b, err := t.MarshalBinary()
 581                         if err != nil {
 582                                 return err
 583                         }
 584
 585                         _, err = rwc.Write(b)
 586                         if err != nil {
 587                                 return err
 588                         }
 589
 590                         time.Sleep(1 * time.Second)
 591                         return nil
 592                 }
 593
 594                 // temporary ban
 595                 if time.Now().Before(*banUntil) {
 596                         t := NewTransaction(
 597                                 TranServerMsg,
 598                                 &[]byte{0, 0},
 599                                 NewField(FieldData, []byte("You are temporarily banned on this server")),
 600                                 NewField(FieldChatOptions, []byte{0, 0}),
 601                         )
 602                         b, err := t.MarshalBinary()
 603                         if err != nil {
 604                                 return err
 605                         }
 606
 607                         _, err = rwc.Write(b)
 608                         if err != nil {
 609                                 return err
 610                         }
 611
 612                         time.Sleep(1 * time.Second)
 613                         return nil
 614                 }
 615         }
 616
 617         c := s.NewClientConn(rwc, remoteAddr)
 618         defer c.Disconnect()
 619
 620         encodedLogin := clientLogin.GetField(FieldUserLogin).Data
 621         encodedPassword := clientLogin.GetField(FieldUserPassword).Data
 622         c.Version = clientLogin.GetField(FieldVersion).Data
 623
 624         var login string
 625         for _, char := range encodedLogin {
 626                 login += string(rune(255 - uint(char)))
 627         }
 628         if login == "" {
 629                 login = GuestAccount
 630         }
 631
 632         c.logger = s.Logger.With("remoteAddr", remoteAddr, "login", login)
 633
 634         // If authentication fails, send error reply and close connection
 635         if !c.Authenticate(login, encodedPassword) {
 636                 t := c.NewErrReply(&clientLogin, "Incorrect login.")
 637                 b, err := t.MarshalBinary()
 638                 if err != nil {
 639                         return err
 640                 }
 641                 if _, err := rwc.Write(b); err != nil {
 642                         return err
 643                 }
 644
 645                 c.logger.Infow("Login failed", "clientVersion", fmt.Sprintf("%x", c.Version))
 646
 647                 return nil
 648         }
 649
 650         if clientLogin.GetField(FieldUserIconID).Data != nil {
 651                 c.Icon = clientLogin.GetField(FieldUserIconID).Data
 652         }
 653
 654         c.Account = c.Server.Accounts[login]
 655
 656         if clientLogin.GetField(FieldUserName).Data != nil {
 657                 if c.Authorize(accessAnyName) {
 658                         c.UserName = clientLogin.GetField(FieldUserName).Data
 659                 } else {
 660                         c.UserName = []byte(c.Account.Name)
 661                 }
 662         }
 663
 664         if c.Authorize(accessDisconUser) {
 665                 c.Flags = []byte{0, 2}
 666         }
 667
 668         s.outbox <- c.NewReply(&clientLogin,
 669                 NewField(FieldVersion, []byte{0x00, 0xbe}),
 670                 NewField(FieldCommunityBannerID, []byte{0, 0}),
 671                 NewField(FieldServerName, []byte(s.Config.Name)),
 672         )
 673
 674         // Send user access privs so client UI knows how to behave
 675         c.Server.outbox <- *NewTransaction(TranUserAccess, c.ID, NewField(FieldUserAccess, c.Account.Access[:]))
 676
 677         // Accounts with accessNoAgreement do not receive the server agreement on login.  The behavior is different between
 678         // client versions.  For 1.2.3 client, we do not send TranShowAgreement.  For other client versions, we send
 679         // TranShowAgreement but with the NoServerAgreement field set to 1.
 680         if c.Authorize(accessNoAgreement) {
 681                 // If client version is nil, then the client uses the 1.2.3 login behavior
 682                 if c.Version != nil {
 683                         c.Server.outbox <- *NewTransaction(TranShowAgreement, c.ID, NewField(FieldNoServerAgreement, []byte{1}))
 684                 }
 685         } else {
 686                 c.Server.outbox <- *NewTransaction(TranShowAgreement, c.ID, NewField(FieldData, s.Agreement))
 687         }
 688
 689         // If the client has provided a username as part of the login, we can infer that it is using the 1.2.3 login
 690         // flow and not the 1.5+ flow.
 691         if len(c.UserName) != 0 {
 692                 // Add the client username to the logger.  For 1.5+ clients, we don't have this information yet as it comes as
 693                 // part of TranAgreed
 694                 c.logger = c.logger.With("name", string(c.UserName))
 695
 696                 c.logger.Infow("Login successful", "clientVersion", "Not sent (probably 1.2.3)")
 697
 698                 // Notify other clients on the server that the new user has logged in.  For 1.5+ clients we don't have this
 699                 // information yet, so we do it in TranAgreed instead
 700                 for _, t := range c.notifyOthers(
 701                         *NewTransaction(
 702                                 TranNotifyChangeUser, nil,
 703                                 NewField(FieldUserName, c.UserName),
 704                                 NewField(FieldUserID, *c.ID),
 705                                 NewField(FieldUserIconID, c.Icon),
 706                                 NewField(FieldUserFlags, c.Flags),
 707                         ),
 708                 ) {
 709                         c.Server.outbox <- t
 710                 }
 711         }
 712
 713         c.Server.Stats.ConnectionCounter += 1
 714         if len(s.Clients) > c.Server.Stats.ConnectionPeak {
 715                 c.Server.Stats.ConnectionPeak = len(s.Clients)
 716         }
 717
 718         // Scan for new transactions and handle them as they come in.
 719         for scanner.Scan() {
 720                 // Make a new []byte slice and copy the scanner bytes to it.  This is critical to avoid a data race as the
 721                 // scanner re-uses the buffer for subsequent scans.
 722                 buf := make([]byte, len(scanner.Bytes()))
 723                 copy(buf, scanner.Bytes())
 724
 725                 var t Transaction
 726                 if _, err := t.Write(buf); err != nil {
 727                         return err
 728                 }
 729
 730                 if err := c.handleTransaction(t); err != nil {
 731                         c.logger.Errorw("Error handling transaction", "err", err)
 732                 }
 733         }
 734         return nil
 735 }
 736
 737 func (s *Server) NewPrivateChat(cc *ClientConn) []byte {
 738         s.PrivateChatsMu.Lock()
 739         defer s.PrivateChatsMu.Unlock()
 740
 741         randID := make([]byte, 4)
 742         rand.Read(randID)
 743         data := binary.BigEndian.Uint32(randID[:])
 744
 745         s.PrivateChats[data] = &PrivateChat{
 746                 ClientConn: make(map[uint16]*ClientConn),
 747         }
 748         s.PrivateChats[data].ClientConn[cc.uint16ID()] = cc
 749
 750         return randID
 751 }
 752
 753 const dlFldrActionSendFile = 1
 754 const dlFldrActionResumeFile = 2
 755 const dlFldrActionNextFile = 3
 756
 757 // handleFileTransfer receives a client net.Conn from the file transfer server, performs the requested transfer type, then closes the connection
 758 func (s *Server) handleFileTransfer(ctx context.Context, rwc io.ReadWriter) error {
 759         defer dontPanic(s.Logger)
 760
 761         txBuf := make([]byte, 16)
 762         if _, err := io.ReadFull(rwc, txBuf); err != nil {
 763                 return err
 764         }
 765
 766         var t transfer
 767         if _, err := t.Write(txBuf); err != nil {
 768                 return err
 769         }
 770
 771         defer func() {
 772                 s.mux.Lock()
 773                 delete(s.fileTransfers, t.ReferenceNumber)
 774                 s.mux.Unlock()
 775
 776                 // Wait a few seconds before closing the connection: this is a workaround for problems
 777                 // observed with Windows clients where the client must initiate close of the TCP connection before
 778                 // the server does.  This is gross and seems unnecessary.  TODO: Revisit?
 779                 time.Sleep(3 * time.Second)
 780         }()
 781
 782         s.mux.Lock()
 783         fileTransfer, ok := s.fileTransfers[t.ReferenceNumber]
 784         s.mux.Unlock()
 785         if !ok {
 786                 return errors.New("invalid transaction ID")
 787         }
 788
 789         defer func() {
 790                 fileTransfer.ClientConn.transfersMU.Lock()
 791                 delete(fileTransfer.ClientConn.transfers[fileTransfer.Type], t.ReferenceNumber)
 792                 fileTransfer.ClientConn.transfersMU.Unlock()
 793         }()
 794
 795         rLogger := s.Logger.With(
 796                 "remoteAddr", ctx.Value(contextKeyReq).(requestCtx).remoteAddr,
 797                 "login", fileTransfer.ClientConn.Account.Login,
 798                 "name", string(fileTransfer.ClientConn.UserName),
 799         )
 800
 801         fullPath, err := readPath(s.Config.FileRoot, fileTransfer.FilePath, fileTransfer.FileName)
 802         if err != nil {
 803                 return err
 804         }
 805
 806         switch fileTransfer.Type {
 807         case bannerDownload:
 808                 if err := s.bannerDownload(rwc); err != nil {
 809                         return err
 810                 }
 811         case FileDownload:
 812                 s.Stats.DownloadCounter += 1
 813                 s.Stats.DownloadsInProgress += 1
 814                 defer func() {
 815                         s.Stats.DownloadsInProgress -= 1
 816                 }()
 817
 818                 var dataOffset int64
 819                 if fileTransfer.fileResumeData != nil {
 820                         dataOffset = int64(binary.BigEndian.Uint32(fileTransfer.fileResumeData.ForkInfoList[0].DataSize[:]))
 821                 }
 822
 823                 fw, err := newFileWrapper(s.FS, fullPath, 0)
 824                 if err != nil {
 825                         return err
 826                 }
 827
 828                 rLogger.Infow("File download started", "filePath", fullPath)
 829
 830                 // if file transfer options are included, that means this is a "quick preview" request from a 1.5+ client
 831                 if fileTransfer.options == nil {
 832                         // Start by sending flat file object to client
 833                         if _, err := rwc.Write(fw.ffo.BinaryMarshal()); err != nil {
 834                                 return err
 835                         }
 836                 }
 837
 838                 file, err := fw.dataForkReader()
 839                 if err != nil {
 840                         return err
 841                 }
 842
 843                 br := bufio.NewReader(file)
 844                 if _, err := br.Discard(int(dataOffset)); err != nil {
 845                         return err
 846                 }
 847
 848                 if _, err = io.Copy(rwc, io.TeeReader(br, fileTransfer.bytesSentCounter)); err != nil {
 849                         return err
 850                 }
 851
 852                 // if the client requested to resume transfer, do not send the resource fork header, or it will be appended into the fileWrapper data
 853                 if fileTransfer.fileResumeData == nil {
 854                         err = binary.Write(rwc, binary.BigEndian, fw.rsrcForkHeader())
 855                         if err != nil {
 856                                 return err
 857                         }
 858                 }
 859
 860                 rFile, err := fw.rsrcForkFile()
 861                 if err != nil {
 862                         return nil
 863                 }
 864
 865                 if _, err = io.Copy(rwc, io.TeeReader(rFile, fileTransfer.bytesSentCounter)); err != nil {
 866                         return err
 867                 }
 868
 869         case FileUpload:
 870                 s.Stats.UploadCounter += 1
 871                 s.Stats.UploadsInProgress += 1
 872                 defer func() { s.Stats.UploadsInProgress -= 1 }()
 873
 874                 var file *os.File
 875
 876                 // A file upload has three possible cases:
 877                 // 1) Upload a new file
 878                 // 2) Resume a partially transferred file
 879                 // 3) Replace a fully uploaded file
 880                 //  We have to infer which case applies by inspecting what is already on the filesystem
 881
 882                 // 1) Check for existing file:
 883                 _, err = os.Stat(fullPath)
 884                 if err == nil {
 885                         return errors.New("existing file found at " + fullPath)
 886                 }
 887                 if errors.Is(err, fs.ErrNotExist) {
 888                         // If not found, open or create a new .incomplete file
 889                         file, err = os.OpenFile(fullPath+incompleteFileSuffix, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0644)
 890                         if err != nil {
 891                                 return err
 892                         }
 893                 }
 894
 895                 f, err := newFileWrapper(s.FS, fullPath, 0)
 896                 if err != nil {
 897                         return err
 898                 }
 899
 900                 rLogger.Infow("File upload started", "dstFile", fullPath)
 901
 902                 rForkWriter := io.Discard
 903                 iForkWriter := io.Discard
 904                 if s.Config.PreserveResourceForks {
 905                         rForkWriter, err = f.rsrcForkWriter()
 906                         if err != nil {
 907                                 return err
 908                         }
 909
 910                         iForkWriter, err = f.infoForkWriter()
 911                         if err != nil {
 912                                 return err
 913                         }
 914                 }
 915
 916                 if err := receiveFile(rwc, file, rForkWriter, iForkWriter, fileTransfer.bytesSentCounter); err != nil {
 917                         s.Logger.Error(err)
 918                 }
 919
 920                 if err := file.Close(); err != nil {
 921                         return err
 922                 }
 923
 924                 if err := s.FS.Rename(fullPath+".incomplete", fullPath); err != nil {
 925                         return err
 926                 }
 927
 928                 rLogger.Infow("File upload complete", "dstFile", fullPath)
 929
 930         case FolderDownload:
 931                 s.Stats.DownloadCounter += 1
 932                 s.Stats.DownloadsInProgress += 1
 933                 defer func() { s.Stats.DownloadsInProgress -= 1 }()
 934
 935                 // Folder Download flow:
 936                 // 1. Get filePath from the transfer
 937                 // 2. Iterate over files
 938                 // 3. For each fileWrapper:
 939                 //       Send fileWrapper header to client
 940                 // The client can reply in 3 ways:
 941                 //
 942                 // 1. If type is an odd number (unknown type?), or fileWrapper download for the current fileWrapper is completed:
 943                 //              client sends []byte{0x00, 0x03} to tell the server to continue to the next fileWrapper
 944                 //
 945                 // 2. If download of a fileWrapper is to be resumed:
 946                 //              client sends:
 947                 //                      []byte{0x00, 0x02} // download folder action
 948                 //                      [2]byte // Resume data size
 949                 //                      []byte fileWrapper resume data (see myField_FileResumeData)
 950                 //
 951                 // 3. Otherwise, download of the fileWrapper is requested and client sends []byte{0x00, 0x01}
 952                 //
 953                 // When download is requested (case 2 or 3), server replies with:
 954                 //                      [4]byte - fileWrapper size
 955                 //                      []byte  - Flattened File Object
 956                 //
 957                 // After every fileWrapper download, client could request next fileWrapper with:
 958                 //                      []byte{0x00, 0x03}
 959                 //
 960                 // This notifies the server to send the next item header
 961
 962                 basePathLen := len(fullPath)
 963
 964                 rLogger.Infow("Start folder download", "path", fullPath)
 965
 966                 nextAction := make([]byte, 2)
 967                 if _, err := io.ReadFull(rwc, nextAction); err != nil {
 968                         return err
 969                 }
 970
 971                 i := 0
 972                 err = filepath.Walk(fullPath+"/", func(path string, info os.FileInfo, err error) error {
 973                         s.Stats.DownloadCounter += 1
 974                         i += 1
 975
 976                         if err != nil {
 977                                 return err
 978                         }
 979
 980                         // skip dot files
 981                         if strings.HasPrefix(info.Name(), ".") {
 982                                 return nil
 983                         }
 984
 985                         hlFile, err := newFileWrapper(s.FS, path, 0)
 986                         if err != nil {
 987                                 return err
 988                         }
 989
 990                         subPath := path[basePathLen+1:]
 991                         rLogger.Debugw("Sending fileheader", "i", i, "path", path, "fullFilePath", fullPath, "subPath", subPath, "IsDir", info.IsDir())
 992
 993                         if i == 1 {
 994                                 return nil
 995                         }
 996
 997                         fileHeader := NewFileHeader(subPath, info.IsDir())
 998
 999                         // Send the fileWrapper header to client
1000                         if _, err := rwc.Write(fileHeader.Payload()); err != nil {
1001                                 s.Logger.Errorf("error sending file header: %v", err)
1002                                 return err
1003                         }
1004
1005                         // Read the client's Next Action request
1006                         if _, err := io.ReadFull(rwc, nextAction); err != nil {
1007                                 return err
1008                         }
1009
1010                         rLogger.Debugw("Client folder download action", "action", fmt.Sprintf("%X", nextAction[0:2]))
1011
1012                         var dataOffset int64
1013
1014                         switch nextAction[1] {
1015                         case dlFldrActionResumeFile:
1016                                 // get size of resumeData
1017                                 resumeDataByteLen := make([]byte, 2)
1018                                 if _, err := io.ReadFull(rwc, resumeDataByteLen); err != nil {
1019                                         return err
1020                                 }
1021
1022                                 resumeDataLen := binary.BigEndian.Uint16(resumeDataByteLen)
1023                                 resumeDataBytes := make([]byte, resumeDataLen)
1024                                 if _, err := io.ReadFull(rwc, resumeDataBytes); err != nil {
1025                                         return err
1026                                 }
1027
1028                                 var frd FileResumeData
1029                                 if err := frd.UnmarshalBinary(resumeDataBytes); err != nil {
1030                                         return err
1031                                 }
1032                                 dataOffset = int64(binary.BigEndian.Uint32(frd.ForkInfoList[0].DataSize[:]))
1033                         case dlFldrActionNextFile:
1034                                 // client asked to skip this file
1035                                 return nil
1036                         }
1037
1038                         if info.IsDir() {
1039                                 return nil
1040                         }
1041
1042                         rLogger.Infow("File download started",
1043                                 "fileName", info.Name(),
1044                                 "TransferSize", fmt.Sprintf("%x", hlFile.ffo.TransferSize(dataOffset)),
1045                         )
1046
1047                         // Send file size to client
1048                         if _, err := rwc.Write(hlFile.ffo.TransferSize(dataOffset)); err != nil {
1049                                 s.Logger.Error(err)
1050                                 return err
1051                         }
1052
1053                         // Send ffo bytes to client
1054                         if _, err := rwc.Write(hlFile.ffo.BinaryMarshal()); err != nil {
1055                                 s.Logger.Error(err)
1056                                 return err
1057                         }
1058
1059                         file, err := s.FS.Open(path)
1060                         if err != nil {
1061                                 return err
1062                         }
1063
1064                         // wr := bufio.NewWriterSize(rwc, 1460)
1065                         if _, err = io.Copy(rwc, io.TeeReader(file, fileTransfer.bytesSentCounter)); err != nil {
1066                                 return err
1067                         }
1068
1069                         if nextAction[1] != 2 && hlFile.ffo.FlatFileHeader.ForkCount[1] == 3 {
1070                                 err = binary.Write(rwc, binary.BigEndian, hlFile.rsrcForkHeader())
1071                                 if err != nil {
1072                                         return err
1073                                 }
1074
1075                                 rFile, err := hlFile.rsrcForkFile()
1076                                 if err != nil {
1077                                         return err
1078                                 }
1079
1080                                 if _, err = io.Copy(rwc, io.TeeReader(rFile, fileTransfer.bytesSentCounter)); err != nil {
1081                                         return err
1082                                 }
1083                         }
1084
1085                         // Read the client's Next Action request.  This is always 3, I think?
1086                         if _, err := io.ReadFull(rwc, nextAction); err != nil {
1087                                 return err
1088                         }
1089
1090                         return nil
1091                 })
1092
1093                 if err != nil {
1094                         return err
1095                 }
1096
1097         case FolderUpload:
1098                 s.Stats.UploadCounter += 1
1099                 s.Stats.UploadsInProgress += 1
1100                 defer func() { s.Stats.UploadsInProgress -= 1 }()
1101                 rLogger.Infow(
1102                         "Folder upload started",
1103                         "dstPath", fullPath,
1104                         "TransferSize", binary.BigEndian.Uint32(fileTransfer.TransferSize),
1105                         "FolderItemCount", fileTransfer.FolderItemCount,
1106                 )
1107
1108                 // Check if the target folder exists.  If not, create it.
1109                 if _, err := s.FS.Stat(fullPath); os.IsNotExist(err) {
1110                         if err := s.FS.Mkdir(fullPath, 0777); err != nil {
1111                                 return err
1112                         }
1113                 }
1114
1115                 // Begin the folder upload flow by sending the "next file action" to client
1116                 if _, err := rwc.Write([]byte{0, dlFldrActionNextFile}); err != nil {
1117                         return err
1118                 }
1119
1120                 fileSize := make([]byte, 4)
1121
1122                 for i := 0; i < fileTransfer.ItemCount(); i++ {
1123                         s.Stats.UploadCounter += 1
1124
1125                         var fu folderUpload
1126                         if _, err := io.ReadFull(rwc, fu.DataSize[:]); err != nil {
1127                                 return err
1128                         }
1129                         if _, err := io.ReadFull(rwc, fu.IsFolder[:]); err != nil {
1130                                 return err
1131                         }
1132                         if _, err := io.ReadFull(rwc, fu.PathItemCount[:]); err != nil {
1133                                 return err
1134                         }
1135
1136                         fu.FileNamePath = make([]byte, binary.BigEndian.Uint16(fu.DataSize[:])-4) // -4 to subtract the path separator bytes
1137
1138                         if _, err := io.ReadFull(rwc, fu.FileNamePath); err != nil {
1139                                 return err
1140                         }
1141
1142                         rLogger.Infow(
1143                                 "Folder upload continued",
1144                                 "FormattedPath", fu.FormattedPath(),
1145                                 "IsFolder", fmt.Sprintf("%x", fu.IsFolder),
1146                                 "PathItemCount", binary.BigEndian.Uint16(fu.PathItemCount[:]),
1147                         )
1148
1149                         if fu.IsFolder == [2]byte{0, 1} {
1150                                 if _, err := os.Stat(filepath.Join(fullPath, fu.FormattedPath())); os.IsNotExist(err) {
1151                                         if err := os.Mkdir(filepath.Join(fullPath, fu.FormattedPath()), 0777); err != nil {
1152                                                 return err
1153                                         }
1154                                 }
1155
1156                                 // Tell client to send next file
1157                                 if _, err := rwc.Write([]byte{0, dlFldrActionNextFile}); err != nil {
1158                                         return err
1159                                 }
1160                         } else {
1161                                 nextAction := dlFldrActionSendFile
1162
1163                                 // Check if we have the full file already.  If so, send dlFldrAction_NextFile to client to skip.
1164                                 _, err = os.Stat(filepath.Join(fullPath, fu.FormattedPath()))
1165                                 if err != nil && !errors.Is(err, fs.ErrNotExist) {
1166                                         return err
1167                                 }
1168                                 if err == nil {
1169                                         nextAction = dlFldrActionNextFile
1170                                 }
1171
1172                                 //  Check if we have a partial file already.  If so, send dlFldrAction_ResumeFile to client to resume upload.
1173                                 incompleteFile, err := os.Stat(filepath.Join(fullPath, fu.FormattedPath()+incompleteFileSuffix))
1174                                 if err != nil && !errors.Is(err, fs.ErrNotExist) {
1175                                         return err
1176                                 }
1177                                 if err == nil {
1178                                         nextAction = dlFldrActionResumeFile
1179                                 }
1180
1181                                 if _, err := rwc.Write([]byte{0, uint8(nextAction)}); err != nil {
1182                                         return err
1183                                 }
1184
1185                                 switch nextAction {
1186                                 case dlFldrActionNextFile:
1187                                         continue
1188                                 case dlFldrActionResumeFile:
1189                                         offset := make([]byte, 4)
1190                                         binary.BigEndian.PutUint32(offset, uint32(incompleteFile.Size()))
1191
1192                                         file, err := os.OpenFile(fullPath+"/"+fu.FormattedPath()+incompleteFileSuffix, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
1193                                         if err != nil {
1194                                                 return err
1195                                         }
1196
1197                                         fileResumeData := NewFileResumeData([]ForkInfoList{*NewForkInfoList(offset)})
1198
1199                                         b, _ := fileResumeData.BinaryMarshal()
1200
1201                                         bs := make([]byte, 2)
1202                                         binary.BigEndian.PutUint16(bs, uint16(len(b)))
1203
1204                                         if _, err := rwc.Write(append(bs, b...)); err != nil {
1205                                                 return err
1206                                         }
1207
1208                                         if _, err := io.ReadFull(rwc, fileSize); err != nil {
1209                                                 return err
1210                                         }
1211
1212                                         if err := receiveFile(rwc, file, io.Discard, io.Discard, fileTransfer.bytesSentCounter); err != nil {
1213                                                 s.Logger.Error(err)
1214                                         }
1215
1216                                         err = os.Rename(fullPath+"/"+fu.FormattedPath()+".incomplete", fullPath+"/"+fu.FormattedPath())
1217                                         if err != nil {
1218                                                 return err
1219                                         }
1220
1221                                 case dlFldrActionSendFile:
1222                                         if _, err := io.ReadFull(rwc, fileSize); err != nil {
1223                                                 return err
1224                                         }
1225
1226                                         filePath := filepath.Join(fullPath, fu.FormattedPath())
1227
1228                                         hlFile, err := newFileWrapper(s.FS, filePath, 0)
1229                                         if err != nil {
1230                                                 return err
1231                                         }
1232
1233                                         rLogger.Infow("Starting file transfer", "path", filePath, "fileNum", i+1, "fileSize", binary.BigEndian.Uint32(fileSize))
1234
1235                                         incWriter, err := hlFile.incFileWriter()
1236                                         if err != nil {
1237                                                 return err
1238                                         }
1239
1240                                         rForkWriter := io.Discard
1241                                         iForkWriter := io.Discard
1242                                         if s.Config.PreserveResourceForks {
1243                                                 iForkWriter, err = hlFile.infoForkWriter()
1244                                                 if err != nil {
1245                                                         return err
1246                                                 }
1247
1248                                                 rForkWriter, err = hlFile.rsrcForkWriter()
1249                                                 if err != nil {
1250                                                         return err
1251                                                 }
1252                                         }
1253                                         if err := receiveFile(rwc, incWriter, rForkWriter, iForkWriter, fileTransfer.bytesSentCounter); err != nil {
1254                                                 return err
1255                                         }
1256
1257                                         if err := os.Rename(filePath+".incomplete", filePath); err != nil {
1258                                                 return err
1259                                         }
1260                                 }
1261
1262                                 // Tell client to send next fileWrapper
1263                                 if _, err := rwc.Write([]byte{0, dlFldrActionNextFile}); err != nil {
1264                                         return err
1265                                 }
1266                         }
1267                 }
1268                 rLogger.Infof("Folder upload complete")
1269         }
1270
1271         return nil
1272 }