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

   1 package hotline
   2
   3 import (
   4         "bufio"
   5         "bytes"
   6         "context"
   7         "encoding/binary"
   8         "errors"
   9         "fmt"
  10         "github.com/go-playground/validator/v10"
  11         "go.uber.org/zap"
  12         "gopkg.in/yaml.v3"
  13         "io"
  14         "io/fs"
  15         "io/ioutil"
  16         "math/big"
  17         "math/rand"
  18         "net"
  19         "os"
  20         "path/filepath"
  21         "runtime/debug"
  22         "strings"
  23         "sync"
  24         "time"
  25 )
  26
  27 type contextKey string
  28
  29 var contextKeyReq = contextKey("req")
  30
  31 type requestCtx struct {
  32         remoteAddr string
  33         login      string
  34         name       string
  35 }
  36
  37 const (
  38         userIdleSeconds        = 300 // time in seconds before an inactive user is marked idle
  39         idleCheckInterval      = 10  // time in seconds to check for idle users
  40         trackerUpdateFrequency = 300 // time in seconds between tracker re-registration
  41 )
  42
  43 var nostalgiaVersion = []byte{0, 0, 2, 0x2c} // version ID used by the Nostalgia client
  44
  45 type Server struct {
  46         Port          int
  47         Accounts      map[string]*Account
  48         Agreement     []byte
  49         Clients       map[uint16]*ClientConn
  50         fileTransfers map[[4]byte]*FileTransfer
  51
  52         Config        *Config
  53         ConfigDir     string
  54         Logger        *zap.SugaredLogger
  55         PrivateChats  map[uint32]*PrivateChat
  56         NextGuestID   *uint16
  57         TrackerPassID [4]byte
  58         Stats         *Stats
  59
  60         FS FileStore // Storage backend to use for File storage
  61
  62         outbox chan Transaction
  63         mux    sync.Mutex
  64
  65         threadedNewsMux sync.Mutex
  66         ThreadedNews    *ThreadedNews
  67
  68         flatNewsMux sync.Mutex
  69         FlatNews    []byte
  70
  71         banListMU sync.Mutex
  72         banList   map[string]*time.Time
  73 }
  74
  75 type PrivateChat struct {
  76         Subject    string
  77         ClientConn map[uint16]*ClientConn
  78 }
  79
  80 func (s *Server) ListenAndServe(ctx context.Context, cancelRoot context.CancelFunc) error {
  81         s.Logger.Infow("Hotline server started",
  82                 "version", VERSION,
  83                 "API port", fmt.Sprintf(":%v", s.Port),
  84                 "Transfer port", fmt.Sprintf(":%v", s.Port+1),
  85         )
  86
  87         var wg sync.WaitGroup
  88
  89         wg.Add(1)
  90         go func() {
  91                 ln, err := net.Listen("tcp", fmt.Sprintf("%s:%v", "", s.Port))
  92                 if err != nil {
  93                         s.Logger.Fatal(err)
  94                 }
  95
  96                 s.Logger.Fatal(s.Serve(ctx, ln))
  97         }()
  98
  99         wg.Add(1)
 100         go func() {
 101                 ln, err := net.Listen("tcp", fmt.Sprintf("%s:%v", "", s.Port+1))
 102                 if err != nil {
 103                         s.Logger.Fatal(err)
 104
 105                 }
 106
 107                 s.Logger.Fatal(s.ServeFileTransfers(ctx, ln))
 108         }()
 109
 110         wg.Wait()
 111
 112         return nil
 113 }
 114
 115 func (s *Server) ServeFileTransfers(ctx context.Context, ln net.Listener) error {
 116         for {
 117                 conn, err := ln.Accept()
 118                 if err != nil {
 119                         return err
 120                 }
 121
 122                 go func() {
 123                         defer func() { _ = conn.Close() }()
 124
 125                         err = s.handleFileTransfer(
 126                                 context.WithValue(ctx, contextKeyReq, requestCtx{
 127                                         remoteAddr: conn.RemoteAddr().String(),
 128                                 }),
 129                                 conn,
 130                         )
 131
 132                         if err != nil {
 133                                 s.Logger.Errorw("file transfer error", "reason", err)
 134                         }
 135                 }()
 136         }
 137 }
 138
 139 func (s *Server) sendTransaction(t Transaction) error {
 140         clientID, err := byteToInt(*t.clientID)
 141         if err != nil {
 142                 return err
 143         }
 144
 145         s.mux.Lock()
 146         client := s.Clients[uint16(clientID)]
 147         if client == nil {
 148                 return fmt.Errorf("invalid client id %v", *t.clientID)
 149         }
 150
 151         s.mux.Unlock()
 152
 153         b, err := t.MarshalBinary()
 154         if err != nil {
 155                 return err
 156         }
 157
 158         if _, err := client.Connection.Write(b); err != nil {
 159                 return err
 160         }
 161
 162         return nil
 163 }
 164
 165 func (s *Server) processOutbox() {
 166         for {
 167                 t := <-s.outbox
 168                 go func() {
 169                         if err := s.sendTransaction(t); err != nil {
 170                                 s.Logger.Errorw("error sending transaction", "err", err)
 171                         }
 172                 }()
 173         }
 174 }
 175
 176 func (s *Server) Serve(ctx context.Context, ln net.Listener) error {
 177         go s.processOutbox()
 178
 179         for {
 180                 conn, err := ln.Accept()
 181                 if err != nil {
 182                         s.Logger.Errorw("error accepting connection", "err", err)
 183                 }
 184                 connCtx := context.WithValue(ctx, contextKeyReq, requestCtx{
 185                         remoteAddr: conn.RemoteAddr().String(),
 186                 })
 187
 188                 go func() {
 189                         s.Logger.Infow("Connection established", "RemoteAddr", conn.RemoteAddr())
 190
 191                         defer conn.Close()
 192                         if err := s.handleNewConnection(connCtx, conn, conn.RemoteAddr().String()); err != nil {
 193                                 if err == io.EOF {
 194                                         s.Logger.Infow("Client disconnected", "RemoteAddr", conn.RemoteAddr())
 195                                 } else {
 196                                         s.Logger.Errorw("error serving request", "RemoteAddr", conn.RemoteAddr(), "err", err)
 197                                 }
 198                         }
 199                 }()
 200         }
 201 }
 202
 203 const (
 204         agreementFile = "Agreement.txt"
 205 )
 206
 207 // NewServer constructs a new Server from a config dir
 208 func NewServer(configDir string, netPort int, logger *zap.SugaredLogger, FS FileStore) (*Server, error) {
 209         server := Server{
 210                 Port:          netPort,
 211                 Accounts:      make(map[string]*Account),
 212                 Config:        new(Config),
 213                 Clients:       make(map[uint16]*ClientConn),
 214                 fileTransfers: make(map[[4]byte]*FileTransfer),
 215                 PrivateChats:  make(map[uint32]*PrivateChat),
 216                 ConfigDir:     configDir,
 217                 Logger:        logger,
 218                 NextGuestID:   new(uint16),
 219                 outbox:        make(chan Transaction),
 220                 Stats:         &Stats{StartTime: time.Now()},
 221                 ThreadedNews:  &ThreadedNews{},
 222                 FS:            FS,
 223                 banList:       make(map[string]*time.Time),
 224         }
 225
 226         var err error
 227
 228         // generate a new random passID for tracker registration
 229         if _, err := rand.Read(server.TrackerPassID[:]); err != nil {
 230                 return nil, err
 231         }
 232
 233         server.Agreement, err = os.ReadFile(filepath.Join(configDir, agreementFile))
 234         if err != nil {
 235                 return nil, err
 236         }
 237
 238         if server.FlatNews, err = os.ReadFile(filepath.Join(configDir, "MessageBoard.txt")); err != nil {
 239                 return nil, err
 240         }
 241
 242         // try to load the ban list, but ignore errors as this file may not be present or may be empty
 243         _ = server.loadBanList(filepath.Join(configDir, "Banlist.yaml"))
 244
 245         if err := server.loadThreadedNews(filepath.Join(configDir, "ThreadedNews.yaml")); err != nil {
 246                 return nil, err
 247         }
 248
 249         if err := server.loadConfig(filepath.Join(configDir, "config.yaml")); err != nil {
 250                 return nil, err
 251         }
 252
 253         if err := server.loadAccounts(filepath.Join(configDir, "Users/")); err != nil {
 254                 return nil, err
 255         }
 256
 257         server.Config.FileRoot = filepath.Join(configDir, "Files")
 258
 259         *server.NextGuestID = 1
 260
 261         if server.Config.EnableTrackerRegistration {
 262                 server.Logger.Infow(
 263                         "Tracker registration enabled",
 264                         "frequency", fmt.Sprintf("%vs", trackerUpdateFrequency),
 265                         "trackers", server.Config.Trackers,
 266                 )
 267
 268                 go func() {
 269                         for {
 270                                 tr := &TrackerRegistration{
 271                                         UserCount:   server.userCount(),
 272                                         PassID:      server.TrackerPassID[:],
 273                                         Name:        server.Config.Name,
 274                                         Description: server.Config.Description,
 275                                 }
 276                                 binary.BigEndian.PutUint16(tr.Port[:], uint16(server.Port))
 277                                 for _, t := range server.Config.Trackers {
 278                                         if err := register(t, tr); err != nil {
 279                                                 server.Logger.Errorw("unable to register with tracker %v", "error", err)
 280                                         }
 281                                         server.Logger.Debugw("Sent Tracker registration", "addr", t)
 282                                 }
 283
 284                                 time.Sleep(trackerUpdateFrequency * time.Second)
 285                         }
 286                 }()
 287         }
 288
 289         // Start Client Keepalive go routine
 290         go server.keepaliveHandler()
 291
 292         return &server, nil
 293 }
 294
 295 func (s *Server) userCount() int {
 296         s.mux.Lock()
 297         defer s.mux.Unlock()
 298
 299         return len(s.Clients)
 300 }
 301
 302 func (s *Server) keepaliveHandler() {
 303         for {
 304                 time.Sleep(idleCheckInterval * time.Second)
 305                 s.mux.Lock()
 306
 307                 for _, c := range s.Clients {
 308                         c.IdleTime += idleCheckInterval
 309                         if c.IdleTime > userIdleSeconds && !c.Idle {
 310                                 c.Idle = true
 311
 312                                 flagBitmap := big.NewInt(int64(binary.BigEndian.Uint16(c.Flags)))
 313                                 flagBitmap.SetBit(flagBitmap, userFlagAway, 1)
 314                                 binary.BigEndian.PutUint16(c.Flags, uint16(flagBitmap.Int64()))
 315
 316                                 c.sendAll(
 317                                         tranNotifyChangeUser,
 318                                         NewField(fieldUserID, *c.ID),
 319                                         NewField(fieldUserFlags, c.Flags),
 320                                         NewField(fieldUserName, c.UserName),
 321                                         NewField(fieldUserIconID, c.Icon),
 322                                 )
 323                         }
 324                 }
 325                 s.mux.Unlock()
 326         }
 327 }
 328
 329 func (s *Server) writeBanList() error {
 330         s.banListMU.Lock()
 331         defer s.banListMU.Unlock()
 332
 333         out, err := yaml.Marshal(s.banList)
 334         if err != nil {
 335                 return err
 336         }
 337         err = ioutil.WriteFile(
 338                 filepath.Join(s.ConfigDir, "Banlist.yaml"),
 339                 out,
 340                 0666,
 341         )
 342         return err
 343 }
 344
 345 func (s *Server) writeThreadedNews() error {
 346         s.threadedNewsMux.Lock()
 347         defer s.threadedNewsMux.Unlock()
 348
 349         out, err := yaml.Marshal(s.ThreadedNews)
 350         if err != nil {
 351                 return err
 352         }
 353         err = s.FS.WriteFile(
 354                 filepath.Join(s.ConfigDir, "ThreadedNews.yaml"),
 355                 out,
 356                 0666,
 357         )
 358         return err
 359 }
 360
 361 func (s *Server) NewClientConn(conn io.ReadWriteCloser, remoteAddr string) *ClientConn {
 362         s.mux.Lock()
 363         defer s.mux.Unlock()
 364
 365         clientConn := &ClientConn{
 366                 ID:         &[]byte{0, 0},
 367                 Icon:       []byte{0, 0},
 368                 Flags:      []byte{0, 0},
 369                 UserName:   []byte{},
 370                 Connection: conn,
 371                 Server:     s,
 372                 Version:    []byte{},
 373                 AutoReply:  []byte{},
 374                 transfers:  map[int]map[[4]byte]*FileTransfer{},
 375                 Agreed:     false,
 376                 RemoteAddr: remoteAddr,
 377         }
 378         clientConn.transfers = map[int]map[[4]byte]*FileTransfer{
 379                 FileDownload:   {},
 380                 FileUpload:     {},
 381                 FolderDownload: {},
 382                 FolderUpload:   {},
 383                 bannerDownload: {},
 384         }
 385
 386         *s.NextGuestID++
 387         ID := *s.NextGuestID
 388
 389         binary.BigEndian.PutUint16(*clientConn.ID, ID)
 390         s.Clients[ID] = clientConn
 391
 392         return clientConn
 393 }
 394
 395 // NewUser creates a new user account entry in the server map and config file
 396 func (s *Server) NewUser(login, name, password string, access accessBitmap) error {
 397         s.mux.Lock()
 398         defer s.mux.Unlock()
 399
 400         account := Account{
 401                 Login:    login,
 402                 Name:     name,
 403                 Password: hashAndSalt([]byte(password)),
 404                 Access:   access,
 405         }
 406         out, err := yaml.Marshal(&account)
 407         if err != nil {
 408                 return err
 409         }
 410         s.Accounts[login] = &account
 411
 412         return s.FS.WriteFile(filepath.Join(s.ConfigDir, "Users", login+".yaml"), out, 0666)
 413 }
 414
 415 func (s *Server) UpdateUser(login, newLogin, name, password string, access accessBitmap) error {
 416         s.mux.Lock()
 417         defer s.mux.Unlock()
 418
 419         // update renames the user login
 420         if login != newLogin {
 421                 err := os.Rename(filepath.Join(s.ConfigDir, "Users", login+".yaml"), filepath.Join(s.ConfigDir, "Users", newLogin+".yaml"))
 422                 if err != nil {
 423                         return err
 424                 }
 425                 s.Accounts[newLogin] = s.Accounts[login]
 426                 delete(s.Accounts, login)
 427         }
 428
 429         account := s.Accounts[newLogin]
 430         account.Access = access
 431         account.Name = name
 432         account.Password = password
 433
 434         out, err := yaml.Marshal(&account)
 435         if err != nil {
 436                 return err
 437         }
 438
 439         if err := os.WriteFile(filepath.Join(s.ConfigDir, "Users", newLogin+".yaml"), out, 0666); err != nil {
 440                 return err
 441         }
 442
 443         return nil
 444 }
 445
 446 // DeleteUser deletes the user account
 447 func (s *Server) DeleteUser(login string) error {
 448         s.mux.Lock()
 449         defer s.mux.Unlock()
 450
 451         delete(s.Accounts, login)
 452
 453         return s.FS.Remove(filepath.Join(s.ConfigDir, "Users", login+".yaml"))
 454 }
 455
 456 func (s *Server) connectedUsers() []Field {
 457         s.mux.Lock()
 458         defer s.mux.Unlock()
 459
 460         var connectedUsers []Field
 461         for _, c := range sortedClients(s.Clients) {
 462                 if !c.Agreed {
 463                         continue
 464                 }
 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 // dontPanic logs panics instead of crashing
 546 func dontPanic(logger *zap.SugaredLogger) {
 547         if r := recover(); r != nil {
 548                 fmt.Println("stacktrace from panic: \n" + string(debug.Stack()))
 549                 logger.Errorw("PANIC", "err", r, "trace", string(debug.Stack()))
 550         }
 551 }
 552
 553 // handleNewConnection takes a new net.Conn and performs the initial login sequence
 554 func (s *Server) handleNewConnection(ctx context.Context, rwc io.ReadWriteCloser, remoteAddr string) error {
 555         defer dontPanic(s.Logger)
 556
 557         if err := Handshake(rwc); err != nil {
 558                 return err
 559         }
 560
 561         // Create a new scanner for parsing incoming bytes into transaction tokens
 562         scanner := bufio.NewScanner(rwc)
 563         scanner.Split(transactionScanner)
 564
 565         scanner.Scan()
 566
 567         clientLogin, _, err := ReadTransaction(scanner.Bytes())
 568         if err != nil {
 569                 panic(err)
 570         }
 571
 572         c := s.NewClientConn(rwc, remoteAddr)
 573
 574         // check if remoteAddr is present in the ban list
 575         if banUntil, ok := s.banList[strings.Split(remoteAddr, ":")[0]]; ok {
 576                 // permaban
 577                 if banUntil == nil {
 578                         s.outbox <- *NewTransaction(
 579                                 tranServerMsg,
 580                                 c.ID,
 581                                 NewField(fieldData, []byte("You are permanently banned on this server")),
 582                                 NewField(fieldChatOptions, []byte{0, 0}),
 583                         )
 584                         time.Sleep(1 * time.Second)
 585                         return nil
 586                 } else if time.Now().Before(*banUntil) {
 587                         s.outbox <- *NewTransaction(
 588                                 tranServerMsg,
 589                                 c.ID,
 590                                 NewField(fieldData, []byte("You are temporarily banned on this server")),
 591                                 NewField(fieldChatOptions, []byte{0, 0}),
 592                         )
 593                         time.Sleep(1 * time.Second)
 594                         return nil
 595                 }
 596
 597         }
 598         defer c.Disconnect()
 599
 600         encodedLogin := clientLogin.GetField(fieldUserLogin).Data
 601         encodedPassword := clientLogin.GetField(fieldUserPassword).Data
 602         c.Version = clientLogin.GetField(fieldVersion).Data
 603
 604         var login string
 605         for _, char := range encodedLogin {
 606                 login += string(rune(255 - uint(char)))
 607         }
 608         if login == "" {
 609                 login = GuestAccount
 610         }
 611
 612         c.logger = s.Logger.With("remoteAddr", remoteAddr, "login", login)
 613
 614         // If authentication fails, send error reply and close connection
 615         if !c.Authenticate(login, encodedPassword) {
 616                 t := c.NewErrReply(clientLogin, "Incorrect login.")
 617                 b, err := t.MarshalBinary()
 618                 if err != nil {
 619                         return err
 620                 }
 621                 if _, err := rwc.Write(b); err != nil {
 622                         return err
 623                 }
 624
 625                 c.logger.Infow("Login failed", "clientVersion", fmt.Sprintf("%x", c.Version))
 626
 627                 return nil
 628         }
 629
 630         if clientLogin.GetField(fieldUserIconID).Data != nil {
 631                 c.Icon = clientLogin.GetField(fieldUserIconID).Data
 632         }
 633
 634         c.Account = c.Server.Accounts[login]
 635
 636         if clientLogin.GetField(fieldUserName).Data != nil {
 637                 if c.Authorize(accessAnyName) {
 638                         c.UserName = clientLogin.GetField(fieldUserName).Data
 639                 } else {
 640                         c.UserName = []byte(c.Account.Name)
 641                 }
 642         }
 643
 644         if c.Authorize(accessDisconUser) {
 645                 c.Flags = []byte{0, 2}
 646         }
 647
 648         s.outbox <- c.NewReply(clientLogin,
 649                 NewField(fieldVersion, []byte{0x00, 0xbe}),
 650                 NewField(fieldCommunityBannerID, []byte{0, 0}),
 651                 NewField(fieldServerName, []byte(s.Config.Name)),
 652         )
 653
 654         // Send user access privs so client UI knows how to behave
 655         c.Server.outbox <- *NewTransaction(tranUserAccess, c.ID, NewField(fieldUserAccess, c.Account.Access[:]))
 656
 657         // Accounts with accessNoAgreement do not receive the server agreement on login.  The behavior is different between
 658         // client versions.  For 1.2.3 client, we do not send tranShowAgreement.  For other client versions, we send
 659         // tranShowAgreement but with the NoServerAgreement field set to 1.
 660         if c.Authorize(accessNoAgreement) {
 661                 // If client version is nil, then the client uses the 1.2.3 login behavior
 662                 if c.Version != nil {
 663                         c.Server.outbox <- *NewTransaction(tranShowAgreement, c.ID, NewField(fieldNoServerAgreement, []byte{1}))
 664                 }
 665         } else {
 666                 c.Server.outbox <- *NewTransaction(tranShowAgreement, c.ID, NewField(fieldData, s.Agreement))
 667         }
 668
 669         // Used simplified hotline v1.2.3 login flow for clients that do not send login info in tranAgreed
 670         if c.Version == nil || bytes.Equal(c.Version, nostalgiaVersion) {
 671                 c.Agreed = true
 672                 c.logger = c.logger.With("name", string(c.UserName))
 673                 c.logger.Infow("Login successful", "clientVersion", fmt.Sprintf("%v", func() int { i, _ := byteToInt(c.Version); return i }()))
 674
 675                 for _, t := range c.notifyOthers(
 676                         *NewTransaction(
 677                                 tranNotifyChangeUser, nil,
 678                                 NewField(fieldUserName, c.UserName),
 679                                 NewField(fieldUserID, *c.ID),
 680                                 NewField(fieldUserIconID, c.Icon),
 681                                 NewField(fieldUserFlags, c.Flags),
 682                         ),
 683                 ) {
 684                         c.Server.outbox <- t
 685                 }
 686         }
 687
 688         c.Server.Stats.LoginCount += 1
 689
 690         // Scan for new transactions and handle them as they come in.
 691         for scanner.Scan() {
 692                 // Make a new []byte slice and copy the scanner bytes to it.  This is critical to avoid a data race as the
 693                 // scanner re-uses the buffer for subsequent scans.
 694                 buf := make([]byte, len(scanner.Bytes()))
 695                 copy(buf, scanner.Bytes())
 696
 697                 t, _, err := ReadTransaction(buf)
 698                 if err != nil {
 699                         panic(err)
 700                 }
 701                 if err := c.handleTransaction(*t); err != nil {
 702                         c.logger.Errorw("Error handling transaction", "err", err)
 703                 }
 704         }
 705         return nil
 706 }
 707
 708 func (s *Server) NewPrivateChat(cc *ClientConn) []byte {
 709         s.mux.Lock()
 710         defer s.mux.Unlock()
 711
 712         randID := make([]byte, 4)
 713         rand.Read(randID)
 714         data := binary.BigEndian.Uint32(randID[:])
 715
 716         s.PrivateChats[data] = &PrivateChat{
 717                 Subject:    "",
 718                 ClientConn: make(map[uint16]*ClientConn),
 719         }
 720         s.PrivateChats[data].ClientConn[cc.uint16ID()] = cc
 721
 722         return randID
 723 }
 724
 725 const dlFldrActionSendFile = 1
 726 const dlFldrActionResumeFile = 2
 727 const dlFldrActionNextFile = 3
 728
 729 // handleFileTransfer receives a client net.Conn from the file transfer server, performs the requested transfer type, then closes the connection
 730 func (s *Server) handleFileTransfer(ctx context.Context, rwc io.ReadWriter) error {
 731         defer dontPanic(s.Logger)
 732
 733         txBuf := make([]byte, 16)
 734         if _, err := io.ReadFull(rwc, txBuf); err != nil {
 735                 return err
 736         }
 737
 738         var t transfer
 739         if _, err := t.Write(txBuf); err != nil {
 740                 return err
 741         }
 742
 743         defer func() {
 744                 s.mux.Lock()
 745                 delete(s.fileTransfers, t.ReferenceNumber)
 746                 s.mux.Unlock()
 747
 748         }()
 749
 750         s.mux.Lock()
 751         fileTransfer, ok := s.fileTransfers[t.ReferenceNumber]
 752         s.mux.Unlock()
 753         if !ok {
 754                 return errors.New("invalid transaction ID")
 755         }
 756
 757         defer func() {
 758                 fileTransfer.ClientConn.transfersMU.Lock()
 759                 delete(fileTransfer.ClientConn.transfers[fileTransfer.Type], t.ReferenceNumber)
 760                 fileTransfer.ClientConn.transfersMU.Unlock()
 761         }()
 762
 763         rLogger := s.Logger.With(
 764                 "remoteAddr", ctx.Value(contextKeyReq).(requestCtx).remoteAddr,
 765                 "login", fileTransfer.ClientConn.Account.Login,
 766                 "name", string(fileTransfer.ClientConn.UserName),
 767         )
 768
 769         fullPath, err := readPath(s.Config.FileRoot, fileTransfer.FilePath, fileTransfer.FileName)
 770         if err != nil {
 771                 return err
 772         }
 773
 774         switch fileTransfer.Type {
 775         case bannerDownload:
 776                 if err := s.bannerDownload(rwc); err != nil {
 777                         panic(err)
 778                         return err
 779                 }
 780         case FileDownload:
 781                 s.Stats.DownloadCounter += 1
 782
 783                 var dataOffset int64
 784                 if fileTransfer.fileResumeData != nil {
 785                         dataOffset = int64(binary.BigEndian.Uint32(fileTransfer.fileResumeData.ForkInfoList[0].DataSize[:]))
 786                 }
 787
 788                 fw, err := newFileWrapper(s.FS, fullPath, 0)
 789                 if err != nil {
 790                         return err
 791                 }
 792
 793                 rLogger.Infow("File download started", "filePath", fullPath)
 794
 795                 // if file transfer options are included, that means this is a "quick preview" request from a 1.5+ client
 796                 if fileTransfer.options == nil {
 797                         // Start by sending flat file object to client
 798                         if _, err := rwc.Write(fw.ffo.BinaryMarshal()); err != nil {
 799                                 return err
 800                         }
 801                 }
 802
 803                 file, err := fw.dataForkReader()
 804                 if err != nil {
 805                         return err
 806                 }
 807
 808                 br := bufio.NewReader(file)
 809                 if _, err := br.Discard(int(dataOffset)); err != nil {
 810                         return err
 811                 }
 812
 813                 if _, err = io.Copy(rwc, io.TeeReader(br, fileTransfer.bytesSentCounter)); err != nil {
 814                         return err
 815                 }
 816
 817                 // if the client requested to resume transfer, do not send the resource fork header, or it will be appended into the fileWrapper data
 818                 if fileTransfer.fileResumeData == nil {
 819                         err = binary.Write(rwc, binary.BigEndian, fw.rsrcForkHeader())
 820                         if err != nil {
 821                                 return err
 822                         }
 823                 }
 824
 825                 rFile, err := fw.rsrcForkFile()
 826                 if err != nil {
 827                         return nil
 828                 }
 829
 830                 if _, err = io.Copy(rwc, io.TeeReader(rFile, fileTransfer.bytesSentCounter)); err != nil {
 831                         return err
 832                 }
 833
 834         case FileUpload:
 835                 s.Stats.UploadCounter += 1
 836
 837                 var file *os.File
 838
 839                 // A file upload has three possible cases:
 840                 // 1) Upload a new file
 841                 // 2) Resume a partially transferred file
 842                 // 3) Replace a fully uploaded file
 843                 //  We have to infer which case applies by inspecting what is already on the filesystem
 844
 845                 // 1) Check for existing file:
 846                 _, err = os.Stat(fullPath)
 847                 if err == nil {
 848                         return errors.New("existing file found at " + fullPath)
 849                 }
 850                 if errors.Is(err, fs.ErrNotExist) {
 851                         // If not found, open or create a new .incomplete file
 852                         file, err = os.OpenFile(fullPath+incompleteFileSuffix, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0644)
 853                         if err != nil {
 854                                 return err
 855                         }
 856                 }
 857
 858                 f, err := newFileWrapper(s.FS, fullPath, 0)
 859                 if err != nil {
 860                         return err
 861                 }
 862
 863                 rLogger.Infow("File upload started", "dstFile", fullPath)
 864
 865                 rForkWriter := io.Discard
 866                 iForkWriter := io.Discard
 867                 if s.Config.PreserveResourceForks {
 868                         rForkWriter, err = f.rsrcForkWriter()
 869                         if err != nil {
 870                                 return err
 871                         }
 872
 873                         iForkWriter, err = f.infoForkWriter()
 874                         if err != nil {
 875                                 return err
 876                         }
 877                 }
 878
 879                 if err := receiveFile(rwc, file, rForkWriter, iForkWriter, fileTransfer.bytesSentCounter); err != nil {
 880                         s.Logger.Error(err)
 881                 }
 882
 883                 if err := file.Close(); err != nil {
 884                         return err
 885                 }
 886
 887                 if err := s.FS.Rename(fullPath+".incomplete", fullPath); err != nil {
 888                         return err
 889                 }
 890
 891                 rLogger.Infow("File upload complete", "dstFile", fullPath)
 892         case FolderDownload:
 893                 // Folder Download flow:
 894                 // 1. Get filePath from the transfer
 895                 // 2. Iterate over files
 896                 // 3. For each fileWrapper:
 897                 //       Send fileWrapper header to client
 898                 // The client can reply in 3 ways:
 899                 //
 900                 // 1. If type is an odd number (unknown type?), or fileWrapper download for the current fileWrapper is completed:
 901                 //              client sends []byte{0x00, 0x03} to tell the server to continue to the next fileWrapper
 902                 //
 903                 // 2. If download of a fileWrapper is to be resumed:
 904                 //              client sends:
 905                 //                      []byte{0x00, 0x02} // download folder action
 906                 //                      [2]byte // Resume data size
 907                 //                      []byte fileWrapper resume data (see myField_FileResumeData)
 908                 //
 909                 // 3. Otherwise, download of the fileWrapper is requested and client sends []byte{0x00, 0x01}
 910                 //
 911                 // When download is requested (case 2 or 3), server replies with:
 912                 //                      [4]byte - fileWrapper size
 913                 //                      []byte  - Flattened File Object
 914                 //
 915                 // After every fileWrapper download, client could request next fileWrapper with:
 916                 //                      []byte{0x00, 0x03}
 917                 //
 918                 // This notifies the server to send the next item header
 919
 920                 basePathLen := len(fullPath)
 921
 922                 rLogger.Infow("Start folder download", "path", fullPath)
 923
 924                 nextAction := make([]byte, 2)
 925                 if _, err := io.ReadFull(rwc, nextAction); err != nil {
 926                         return err
 927                 }
 928
 929                 i := 0
 930                 err = filepath.Walk(fullPath+"/", func(path string, info os.FileInfo, err error) error {
 931                         s.Stats.DownloadCounter += 1
 932                         i += 1
 933
 934                         if err != nil {
 935                                 return err
 936                         }
 937
 938                         // skip dot files
 939                         if strings.HasPrefix(info.Name(), ".") {
 940                                 return nil
 941                         }
 942
 943                         hlFile, err := newFileWrapper(s.FS, path, 0)
 944                         if err != nil {
 945                                 return err
 946                         }
 947
 948                         subPath := path[basePathLen+1:]
 949                         rLogger.Debugw("Sending fileheader", "i", i, "path", path, "fullFilePath", fullPath, "subPath", subPath, "IsDir", info.IsDir())
 950
 951                         if i == 1 {
 952                                 return nil
 953                         }
 954
 955                         fileHeader := NewFileHeader(subPath, info.IsDir())
 956
 957                         // Send the fileWrapper header to client
 958                         if _, err := rwc.Write(fileHeader.Payload()); err != nil {
 959                                 s.Logger.Errorf("error sending file header: %v", err)
 960                                 return err
 961                         }
 962
 963                         // Read the client's Next Action request
 964                         if _, err := io.ReadFull(rwc, nextAction); err != nil {
 965                                 return err
 966                         }
 967
 968                         rLogger.Debugw("Client folder download action", "action", fmt.Sprintf("%X", nextAction[0:2]))
 969
 970                         var dataOffset int64
 971
 972                         switch nextAction[1] {
 973                         case dlFldrActionResumeFile:
 974                                 // get size of resumeData
 975                                 resumeDataByteLen := make([]byte, 2)
 976                                 if _, err := io.ReadFull(rwc, resumeDataByteLen); err != nil {
 977                                         return err
 978                                 }
 979
 980                                 resumeDataLen := binary.BigEndian.Uint16(resumeDataByteLen)
 981                                 resumeDataBytes := make([]byte, resumeDataLen)
 982                                 if _, err := io.ReadFull(rwc, resumeDataBytes); err != nil {
 983                                         return err
 984                                 }
 985
 986                                 var frd FileResumeData
 987                                 if err := frd.UnmarshalBinary(resumeDataBytes); err != nil {
 988                                         return err
 989                                 }
 990                                 dataOffset = int64(binary.BigEndian.Uint32(frd.ForkInfoList[0].DataSize[:]))
 991                         case dlFldrActionNextFile:
 992                                 // client asked to skip this file
 993                                 return nil
 994                         }
 995
 996                         if info.IsDir() {
 997                                 return nil
 998                         }
 999
1000                         rLogger.Infow("File download started",
1001                                 "fileName", info.Name(),
1002                                 "TransferSize", fmt.Sprintf("%x", hlFile.ffo.TransferSize(dataOffset)),
1003                         )
1004
1005                         // Send file size to client
1006                         if _, err := rwc.Write(hlFile.ffo.TransferSize(dataOffset)); err != nil {
1007                                 s.Logger.Error(err)
1008                                 return err
1009                         }
1010
1011                         // Send ffo bytes to client
1012                         if _, err := rwc.Write(hlFile.ffo.BinaryMarshal()); err != nil {
1013                                 s.Logger.Error(err)
1014                                 return err
1015                         }
1016
1017                         file, err := s.FS.Open(path)
1018                         if err != nil {
1019                                 return err
1020                         }
1021
1022                         // wr := bufio.NewWriterSize(rwc, 1460)
1023                         if _, err = io.Copy(rwc, io.TeeReader(file, fileTransfer.bytesSentCounter)); err != nil {
1024                                 return err
1025                         }
1026
1027                         if nextAction[1] != 2 && hlFile.ffo.FlatFileHeader.ForkCount[1] == 3 {
1028                                 err = binary.Write(rwc, binary.BigEndian, hlFile.rsrcForkHeader())
1029                                 if err != nil {
1030                                         return err
1031                                 }
1032
1033                                 rFile, err := hlFile.rsrcForkFile()
1034                                 if err != nil {
1035                                         return err
1036                                 }
1037
1038                                 if _, err = io.Copy(rwc, io.TeeReader(rFile, fileTransfer.bytesSentCounter)); err != nil {
1039                                         return err
1040                                 }
1041                         }
1042
1043                         // Read the client's Next Action request.  This is always 3, I think?
1044                         if _, err := io.ReadFull(rwc, nextAction); err != nil {
1045                                 return err
1046                         }
1047
1048                         return nil
1049                 })
1050
1051                 if err != nil {
1052                         return err
1053                 }
1054
1055         case FolderUpload:
1056                 rLogger.Infow(
1057                         "Folder upload started",
1058                         "dstPath", fullPath,
1059                         "TransferSize", binary.BigEndian.Uint32(fileTransfer.TransferSize),
1060                         "FolderItemCount", fileTransfer.FolderItemCount,
1061                 )
1062
1063                 // Check if the target folder exists.  If not, create it.
1064                 if _, err := s.FS.Stat(fullPath); os.IsNotExist(err) {
1065                         if err := s.FS.Mkdir(fullPath, 0777); err != nil {
1066                                 return err
1067                         }
1068                 }
1069
1070                 // Begin the folder upload flow by sending the "next file action" to client
1071                 if _, err := rwc.Write([]byte{0, dlFldrActionNextFile}); err != nil {
1072                         return err
1073                 }
1074
1075                 fileSize := make([]byte, 4)
1076
1077                 for i := 0; i < fileTransfer.ItemCount(); i++ {
1078                         s.Stats.UploadCounter += 1
1079
1080                         var fu folderUpload
1081                         if _, err := io.ReadFull(rwc, fu.DataSize[:]); err != nil {
1082                                 return err
1083                         }
1084                         if _, err := io.ReadFull(rwc, fu.IsFolder[:]); err != nil {
1085                                 return err
1086                         }
1087                         if _, err := io.ReadFull(rwc, fu.PathItemCount[:]); err != nil {
1088                                 return err
1089                         }
1090
1091                         fu.FileNamePath = make([]byte, binary.BigEndian.Uint16(fu.DataSize[:])-4) // -4 to subtract the path separator bytes
1092
1093                         if _, err := io.ReadFull(rwc, fu.FileNamePath); err != nil {
1094                                 return err
1095                         }
1096
1097                         rLogger.Infow(
1098                                 "Folder upload continued",
1099                                 "FormattedPath", fu.FormattedPath(),
1100                                 "IsFolder", fmt.Sprintf("%x", fu.IsFolder),
1101                                 "PathItemCount", binary.BigEndian.Uint16(fu.PathItemCount[:]),
1102                         )
1103
1104                         if fu.IsFolder == [2]byte{0, 1} {
1105                                 if _, err := os.Stat(filepath.Join(fullPath, fu.FormattedPath())); os.IsNotExist(err) {
1106                                         if err := os.Mkdir(filepath.Join(fullPath, fu.FormattedPath()), 0777); err != nil {
1107                                                 return err
1108                                         }
1109                                 }
1110
1111                                 // Tell client to send next file
1112                                 if _, err := rwc.Write([]byte{0, dlFldrActionNextFile}); err != nil {
1113                                         return err
1114                                 }
1115                         } else {
1116                                 nextAction := dlFldrActionSendFile
1117
1118                                 // Check if we have the full file already.  If so, send dlFldrAction_NextFile to client to skip.
1119                                 _, err = os.Stat(filepath.Join(fullPath, fu.FormattedPath()))
1120                                 if err != nil && !errors.Is(err, fs.ErrNotExist) {
1121                                         return err
1122                                 }
1123                                 if err == nil {
1124                                         nextAction = dlFldrActionNextFile
1125                                 }
1126
1127                                 //  Check if we have a partial file already.  If so, send dlFldrAction_ResumeFile to client to resume upload.
1128                                 incompleteFile, err := os.Stat(filepath.Join(fullPath, fu.FormattedPath()+incompleteFileSuffix))
1129                                 if err != nil && !errors.Is(err, fs.ErrNotExist) {
1130                                         return err
1131                                 }
1132                                 if err == nil {
1133                                         nextAction = dlFldrActionResumeFile
1134                                 }
1135
1136                                 if _, err := rwc.Write([]byte{0, uint8(nextAction)}); err != nil {
1137                                         return err
1138                                 }
1139
1140                                 switch nextAction {
1141                                 case dlFldrActionNextFile:
1142                                         continue
1143                                 case dlFldrActionResumeFile:
1144                                         offset := make([]byte, 4)
1145                                         binary.BigEndian.PutUint32(offset, uint32(incompleteFile.Size()))
1146
1147                                         file, err := os.OpenFile(fullPath+"/"+fu.FormattedPath()+incompleteFileSuffix, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
1148                                         if err != nil {
1149                                                 return err
1150                                         }
1151
1152                                         fileResumeData := NewFileResumeData([]ForkInfoList{*NewForkInfoList(offset)})
1153
1154                                         b, _ := fileResumeData.BinaryMarshal()
1155
1156                                         bs := make([]byte, 2)
1157                                         binary.BigEndian.PutUint16(bs, uint16(len(b)))
1158
1159                                         if _, err := rwc.Write(append(bs, b...)); err != nil {
1160                                                 return err
1161                                         }
1162
1163                                         if _, err := io.ReadFull(rwc, fileSize); err != nil {
1164                                                 return err
1165                                         }
1166
1167                                         if err := receiveFile(rwc, file, ioutil.Discard, ioutil.Discard, fileTransfer.bytesSentCounter); err != nil {
1168                                                 s.Logger.Error(err)
1169                                         }
1170
1171                                         err = os.Rename(fullPath+"/"+fu.FormattedPath()+".incomplete", fullPath+"/"+fu.FormattedPath())
1172                                         if err != nil {
1173                                                 return err
1174                                         }
1175
1176                                 case dlFldrActionSendFile:
1177                                         if _, err := io.ReadFull(rwc, fileSize); err != nil {
1178                                                 return err
1179                                         }
1180
1181                                         filePath := filepath.Join(fullPath, fu.FormattedPath())
1182
1183                                         hlFile, err := newFileWrapper(s.FS, filePath, 0)
1184                                         if err != nil {
1185                                                 return err
1186                                         }
1187
1188                                         rLogger.Infow("Starting file transfer", "path", filePath, "fileNum", i+1, "fileSize", binary.BigEndian.Uint32(fileSize))
1189
1190                                         incWriter, err := hlFile.incFileWriter()
1191                                         if err != nil {
1192                                                 return err
1193                                         }
1194
1195                                         rForkWriter := io.Discard
1196                                         iForkWriter := io.Discard
1197                                         if s.Config.PreserveResourceForks {
1198                                                 iForkWriter, err = hlFile.infoForkWriter()
1199                                                 if err != nil {
1200                                                         return err
1201                                                 }
1202
1203                                                 rForkWriter, err = hlFile.rsrcForkWriter()
1204                                                 if err != nil {
1205                                                         return err
1206                                                 }
1207                                         }
1208                                         if err := receiveFile(rwc, incWriter, rForkWriter, iForkWriter, fileTransfer.bytesSentCounter); err != nil {
1209                                                 return err
1210                                         }
1211
1212                                         if err := os.Rename(filePath+".incomplete", filePath); err != nil {
1213                                                 return err
1214                                         }
1215                                 }
1216
1217                                 // Tell client to send next fileWrapper
1218                                 if _, err := rwc.Write([]byte{0, dlFldrActionNextFile}); err != nil {
1219                                         return err
1220                                 }
1221                         }
1222                 }
1223                 rLogger.Infof("Folder upload complete")
1224         }
1225
1226         return nil
1227 }