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         "strings"
  22         "sync"
  23         "time"
  24 )
  25
  26 type contextKey string
  27
  28 var contextKeyReq = contextKey("req")
  29
  30 type requestCtx struct {
  31         remoteAddr string
  32         login      string
  33         name       string
  34 }
  35
  36 var nostalgiaVersion = []byte{0, 0, 2, 0x2c} // version ID used by the Nostalgia client
  37 var frogblastVersion = []byte{0, 0, 0, 0xb9} // version ID used by the Frogblast 1.2.4 client
  38
  39 var obsessionVersion = []byte{0xbe, 0x00} // version ID used by the Obsession client
  40
  41 type Server struct {
  42         Port          int
  43         Accounts      map[string]*Account
  44         Agreement     []byte
  45         Clients       map[uint16]*ClientConn
  46         fileTransfers map[[4]byte]*FileTransfer
  47
  48         Config    *Config
  49         ConfigDir string
  50         Logger    *zap.SugaredLogger
  51
  52         PrivateChatsMu sync.Mutex
  53         PrivateChats   map[uint32]*PrivateChat
  54
  55         NextGuestID   *uint16
  56         TrackerPassID [4]byte
  57
  58         StatsMu sync.Mutex
  59         Stats   *Stats
  60
  61         FS FileStore // Storage backend to use for File storage
  62
  63         outbox chan Transaction
  64         mux    sync.Mutex
  65
  66         threadedNewsMux sync.Mutex
  67         ThreadedNews    *ThreadedNews
  68
  69         flatNewsMux sync.Mutex
  70         FlatNews    []byte
  71
  72         banListMU sync.Mutex
  73         banList   map[string]*time.Time
  74 }
  75
  76 func (s *Server) CurrentStats() Stats {
  77         s.StatsMu.Lock()
  78         defer s.StatsMu.Unlock()
  79
  80         stats := s.Stats
  81         stats.CurrentlyConnected = len(s.Clients)
  82
  83         return *stats
  84 }
  85
  86 type PrivateChat struct {
  87         Subject    string
  88         ClientConn map[uint16]*ClientConn
  89 }
  90
  91 func (s *Server) ListenAndServe(ctx context.Context, cancelRoot context.CancelFunc) error {
  92         s.Logger.Infow("Hotline server started",
  93                 "version", VERSION,
  94                 "API port", fmt.Sprintf(":%v", s.Port),
  95                 "Transfer port", fmt.Sprintf(":%v", s.Port+1),
  96         )
  97
  98         var wg sync.WaitGroup
  99
 100         wg.Add(1)
 101         go func() {
 102                 ln, err := net.Listen("tcp", fmt.Sprintf("%s:%v", "", s.Port))
 103                 if err != nil {
 104                         s.Logger.Fatal(err)
 105                 }
 106
 107                 s.Logger.Fatal(s.Serve(ctx, ln))
 108         }()
 109
 110         wg.Add(1)
 111         go func() {
 112                 ln, err := net.Listen("tcp", fmt.Sprintf("%s:%v", "", s.Port+1))
 113                 if err != nil {
 114                         s.Logger.Fatal(err)
 115
 116                 }
 117
 118                 s.Logger.Fatal(s.ServeFileTransfers(ctx, ln))
 119         }()
 120
 121         wg.Wait()
 122
 123         return nil
 124 }
 125
 126 func (s *Server) ServeFileTransfers(ctx context.Context, ln net.Listener) error {
 127         for {
 128                 conn, err := ln.Accept()
 129                 if err != nil {
 130                         return err
 131                 }
 132
 133                 go func() {
 134                         defer func() { _ = conn.Close() }()
 135
 136                         err = s.handleFileTransfer(
 137                                 context.WithValue(ctx, contextKeyReq, requestCtx{
 138                                         remoteAddr: conn.RemoteAddr().String(),
 139                                 }),
 140                                 conn,
 141                         )
 142
 143                         if err != nil {
 144                                 s.Logger.Errorw("file transfer error", "reason", err)
 145                         }
 146                 }()
 147         }
 148 }
 149
 150 func (s *Server) sendTransaction(t Transaction) error {
 151         clientID, err := byteToInt(*t.clientID)
 152         if err != nil {
 153                 return err
 154         }
 155
 156         s.mux.Lock()
 157         client := s.Clients[uint16(clientID)]
 158         s.mux.Unlock()
 159         if client == nil {
 160                 return fmt.Errorf("invalid client id %v", *t.clientID)
 161         }
 162
 163         b, err := t.MarshalBinary()
 164         if err != nil {
 165                 return err
 166         }
 167
 168         _, err = client.Connection.Write(b)
 169         if err != nil {
 170                 return err
 171         }
 172
 173         return nil
 174 }
 175
 176 func (s *Server) processOutbox() {
 177         for {
 178                 t := <-s.outbox
 179                 go func() {
 180                         if err := s.sendTransaction(t); err != nil {
 181                                 s.Logger.Errorw("error sending transaction", "err", err)
 182                         }
 183                 }()
 184         }
 185 }
 186
 187 func (s *Server) Serve(ctx context.Context, ln net.Listener) error {
 188         go s.processOutbox()
 189
 190         for {
 191                 conn, err := ln.Accept()
 192                 if err != nil {
 193                         s.Logger.Errorw("error accepting connection", "err", err)
 194                 }
 195                 connCtx := context.WithValue(ctx, contextKeyReq, requestCtx{
 196                         remoteAddr: conn.RemoteAddr().String(),
 197                 })
 198
 199                 go func() {
 200                         s.Logger.Infow("Connection established", "RemoteAddr", conn.RemoteAddr())
 201
 202                         defer conn.Close()
 203                         if err := s.handleNewConnection(connCtx, conn, conn.RemoteAddr().String()); err != nil {
 204                                 if err == io.EOF {
 205                                         s.Logger.Infow("Client disconnected", "RemoteAddr", conn.RemoteAddr())
 206                                 } else {
 207                                         s.Logger.Errorw("error serving request", "RemoteAddr", conn.RemoteAddr(), "err", err)
 208                                 }
 209                         }
 210                 }()
 211         }
 212 }
 213
 214 const (
 215         agreementFile = "Agreement.txt"
 216 )
 217
 218 // NewServer constructs a new Server from a config dir
 219 func NewServer(configDir string, netPort int, logger *zap.SugaredLogger, FS FileStore) (*Server, error) {
 220         server := Server{
 221                 Port:          netPort,
 222                 Accounts:      make(map[string]*Account),
 223                 Config:        new(Config),
 224                 Clients:       make(map[uint16]*ClientConn),
 225                 fileTransfers: make(map[[4]byte]*FileTransfer),
 226                 PrivateChats:  make(map[uint32]*PrivateChat),
 227                 ConfigDir:     configDir,
 228                 Logger:        logger,
 229                 NextGuestID:   new(uint16),
 230                 outbox:        make(chan Transaction),
 231                 Stats:         &Stats{Since: time.Now()},
 232                 ThreadedNews:  &ThreadedNews{},
 233                 FS:            FS,
 234                 banList:       make(map[string]*time.Time),
 235         }
 236
 237         var err error
 238
 239         // generate a new random passID for tracker registration
 240         if _, err := rand.Read(server.TrackerPassID[:]); err != nil {
 241                 return nil, err
 242         }
 243
 244         server.Agreement, err = os.ReadFile(filepath.Join(configDir, agreementFile))
 245         if err != nil {
 246                 return nil, err
 247         }
 248
 249         if server.FlatNews, err = os.ReadFile(filepath.Join(configDir, "MessageBoard.txt")); err != nil {
 250                 return nil, err
 251         }
 252
 253         // try to load the ban list, but ignore errors as this file may not be present or may be empty
 254         _ = server.loadBanList(filepath.Join(configDir, "Banlist.yaml"))
 255
 256         if err := server.loadThreadedNews(filepath.Join(configDir, "ThreadedNews.yaml")); err != nil {
 257                 return nil, err
 258         }
 259
 260         if err := server.loadConfig(filepath.Join(configDir, "config.yaml")); err != nil {
 261                 return nil, err
 262         }
 263
 264         if err := server.loadAccounts(filepath.Join(configDir, "Users/")); err != nil {
 265                 return nil, err
 266         }
 267
 268         server.Config.FileRoot = filepath.Join(configDir, "Files")
 269
 270         *server.NextGuestID = 1
 271
 272         if server.Config.EnableTrackerRegistration {
 273                 server.Logger.Infow(
 274                         "Tracker registration enabled",
 275                         "frequency", fmt.Sprintf("%vs", trackerUpdateFrequency),
 276                         "trackers", server.Config.Trackers,
 277                 )
 278
 279                 go func() {
 280                         for {
 281                                 tr := &TrackerRegistration{
 282                                         UserCount:   server.userCount(),
 283                                         PassID:      server.TrackerPassID[:],
 284                                         Name:        server.Config.Name,
 285                                         Description: server.Config.Description,
 286                                 }
 287                                 binary.BigEndian.PutUint16(tr.Port[:], uint16(server.Port))
 288                                 for _, t := range server.Config.Trackers {
 289                                         if err := register(t, tr); err != nil {
 290                                                 server.Logger.Errorw("unable to register with tracker %v", "error", err)
 291                                         }
 292                                         server.Logger.Debugw("Sent Tracker registration", "addr", t)
 293                                 }
 294
 295                                 time.Sleep(trackerUpdateFrequency * time.Second)
 296                         }
 297                 }()
 298         }
 299
 300         // Start Client Keepalive go routine
 301         go server.keepaliveHandler()
 302
 303         return &server, nil
 304 }
 305
 306 func (s *Server) userCount() int {
 307         s.mux.Lock()
 308         defer s.mux.Unlock()
 309
 310         return len(s.Clients)
 311 }
 312
 313 func (s *Server) keepaliveHandler() {
 314         for {
 315                 time.Sleep(idleCheckInterval * time.Second)
 316                 s.mux.Lock()
 317
 318                 for _, c := range s.Clients {
 319                         c.IdleTime += idleCheckInterval
 320                         if c.IdleTime > userIdleSeconds && !c.Idle {
 321                                 c.Idle = true
 322
 323                                 flagBitmap := big.NewInt(int64(binary.BigEndian.Uint16(c.Flags)))
 324                                 flagBitmap.SetBit(flagBitmap, userFlagAway, 1)
 325                                 binary.BigEndian.PutUint16(c.Flags, uint16(flagBitmap.Int64()))
 326
 327                                 c.sendAll(
 328                                         tranNotifyChangeUser,
 329                                         NewField(fieldUserID, *c.ID),
 330                                         NewField(fieldUserFlags, c.Flags),
 331                                         NewField(fieldUserName, c.UserName),
 332                                         NewField(fieldUserIconID, c.Icon),
 333                                 )
 334                         }
 335                 }
 336                 s.mux.Unlock()
 337         }
 338 }
 339
 340 func (s *Server) writeBanList() error {
 341         s.banListMU.Lock()
 342         defer s.banListMU.Unlock()
 343
 344         out, err := yaml.Marshal(s.banList)
 345         if err != nil {
 346                 return err
 347         }
 348         err = ioutil.WriteFile(
 349                 filepath.Join(s.ConfigDir, "Banlist.yaml"),
 350                 out,
 351                 0666,
 352         )
 353         return err
 354 }
 355
 356 func (s *Server) writeThreadedNews() error {
 357         s.threadedNewsMux.Lock()
 358         defer s.threadedNewsMux.Unlock()
 359
 360         out, err := yaml.Marshal(s.ThreadedNews)
 361         if err != nil {
 362                 return err
 363         }
 364         err = s.FS.WriteFile(
 365                 filepath.Join(s.ConfigDir, "ThreadedNews.yaml"),
 366                 out,
 367                 0666,
 368         )
 369         return err
 370 }
 371
 372 func (s *Server) NewClientConn(conn io.ReadWriteCloser, remoteAddr string) *ClientConn {
 373         s.mux.Lock()
 374         defer s.mux.Unlock()
 375
 376         clientConn := &ClientConn{
 377                 ID:         &[]byte{0, 0},
 378                 Icon:       []byte{0, 0},
 379                 Flags:      []byte{0, 0},
 380                 UserName:   []byte{},
 381                 Connection: conn,
 382                 Server:     s,
 383                 Version:    []byte{},
 384                 AutoReply:  []byte{},
 385                 transfers:  map[int]map[[4]byte]*FileTransfer{},
 386                 Agreed:     false,
 387                 RemoteAddr: remoteAddr,
 388         }
 389         clientConn.transfers = map[int]map[[4]byte]*FileTransfer{
 390                 FileDownload:   {},
 391                 FileUpload:     {},
 392                 FolderDownload: {},
 393                 FolderUpload:   {},
 394                 bannerDownload: {},
 395         }
 396
 397         *s.NextGuestID++
 398         ID := *s.NextGuestID
 399
 400         binary.BigEndian.PutUint16(*clientConn.ID, ID)
 401         s.Clients[ID] = clientConn
 402
 403         return clientConn
 404 }
 405
 406 // NewUser creates a new user account entry in the server map and config file
 407 func (s *Server) NewUser(login, name, password string, access accessBitmap) error {
 408         s.mux.Lock()
 409         defer s.mux.Unlock()
 410
 411         account := Account{
 412                 Login:    login,
 413                 Name:     name,
 414                 Password: hashAndSalt([]byte(password)),
 415                 Access:   access,
 416         }
 417         out, err := yaml.Marshal(&account)
 418         if err != nil {
 419                 return err
 420         }
 421         s.Accounts[login] = &account
 422
 423         return s.FS.WriteFile(filepath.Join(s.ConfigDir, "Users", login+".yaml"), out, 0666)
 424 }
 425
 426 func (s *Server) UpdateUser(login, newLogin, name, password string, access accessBitmap) error {
 427         s.mux.Lock()
 428         defer s.mux.Unlock()
 429
 430         // update renames the user login
 431         if login != newLogin {
 432                 err := os.Rename(filepath.Join(s.ConfigDir, "Users", login+".yaml"), filepath.Join(s.ConfigDir, "Users", newLogin+".yaml"))
 433                 if err != nil {
 434                         return err
 435                 }
 436                 s.Accounts[newLogin] = s.Accounts[login]
 437                 delete(s.Accounts, login)
 438         }
 439
 440         account := s.Accounts[newLogin]
 441         account.Access = access
 442         account.Name = name
 443         account.Password = password
 444
 445         out, err := yaml.Marshal(&account)
 446         if err != nil {
 447                 return err
 448         }
 449
 450         if err := os.WriteFile(filepath.Join(s.ConfigDir, "Users", newLogin+".yaml"), out, 0666); err != nil {
 451                 return err
 452         }
 453
 454         return nil
 455 }
 456
 457 // DeleteUser deletes the user account
 458 func (s *Server) DeleteUser(login string) error {
 459         s.mux.Lock()
 460         defer s.mux.Unlock()
 461
 462         delete(s.Accounts, login)
 463
 464         return s.FS.Remove(filepath.Join(s.ConfigDir, "Users", login+".yaml"))
 465 }
 466
 467 func (s *Server) connectedUsers() []Field {
 468         s.mux.Lock()
 469         defer s.mux.Unlock()
 470
 471         var connectedUsers []Field
 472         for _, c := range sortedClients(s.Clients) {
 473                 if !c.Agreed {
 474                         continue
 475                 }
 476                 user := User{
 477                         ID:    *c.ID,
 478                         Icon:  c.Icon,
 479                         Flags: c.Flags,
 480                         Name:  string(c.UserName),
 481                 }
 482                 connectedUsers = append(connectedUsers, NewField(fieldUsernameWithInfo, user.Payload()))
 483         }
 484         return connectedUsers
 485 }
 486
 487 func (s *Server) loadBanList(path string) error {
 488         fh, err := os.Open(path)
 489         if err != nil {
 490                 return err
 491         }
 492         decoder := yaml.NewDecoder(fh)
 493
 494         return decoder.Decode(s.banList)
 495 }
 496
 497 // loadThreadedNews loads the threaded news data from disk
 498 func (s *Server) loadThreadedNews(threadedNewsPath string) error {
 499         fh, err := os.Open(threadedNewsPath)
 500         if err != nil {
 501                 return err
 502         }
 503         decoder := yaml.NewDecoder(fh)
 504
 505         return decoder.Decode(s.ThreadedNews)
 506 }
 507
 508 // loadAccounts loads account data from disk
 509 func (s *Server) loadAccounts(userDir string) error {
 510         matches, err := filepath.Glob(filepath.Join(userDir, "*.yaml"))
 511         if err != nil {
 512                 return err
 513         }
 514
 515         if len(matches) == 0 {
 516                 return errors.New("no user accounts found in " + userDir)
 517         }
 518
 519         for _, file := range matches {
 520                 fh, err := s.FS.Open(file)
 521                 if err != nil {
 522                         return err
 523                 }
 524
 525                 account := Account{}
 526                 decoder := yaml.NewDecoder(fh)
 527                 if err := decoder.Decode(&account); err != nil {
 528                         return err
 529                 }
 530
 531                 s.Accounts[account.Login] = &account
 532         }
 533         return nil
 534 }
 535
 536 func (s *Server) loadConfig(path string) error {
 537         fh, err := s.FS.Open(path)
 538         if err != nil {
 539                 return err
 540         }
 541
 542         decoder := yaml.NewDecoder(fh)
 543         err = decoder.Decode(s.Config)
 544         if err != nil {
 545                 return err
 546         }
 547
 548         validate := validator.New()
 549         err = validate.Struct(s.Config)
 550         if err != nil {
 551                 return err
 552         }
 553         return nil
 554 }
 555
 556 // handleNewConnection takes a new net.Conn and performs the initial login sequence
 557 func (s *Server) handleNewConnection(ctx context.Context, rwc io.ReadWriteCloser, remoteAddr string) error {
 558         defer dontPanic(s.Logger)
 559
 560         if err := Handshake(rwc); err != nil {
 561                 return err
 562         }
 563
 564         // Create a new scanner for parsing incoming bytes into transaction tokens
 565         scanner := bufio.NewScanner(rwc)
 566         scanner.Split(transactionScanner)
 567
 568         scanner.Scan()
 569
 570         // Make a new []byte slice and copy the scanner bytes to it.  This is critical to avoid a data race as the
 571         // scanner re-uses the buffer for subsequent scans.
 572         buf := make([]byte, len(scanner.Bytes()))
 573         copy(buf, scanner.Bytes())
 574
 575         var clientLogin Transaction
 576         if _, err := clientLogin.Write(buf); err != nil {
 577                 return err
 578         }
 579
 580         c := s.NewClientConn(rwc, remoteAddr)
 581
 582         // check if remoteAddr is present in the ban list
 583         if banUntil, ok := s.banList[strings.Split(remoteAddr, ":")[0]]; ok {
 584                 // permaban
 585                 if banUntil == nil {
 586                         s.outbox <- *NewTransaction(
 587                                 tranServerMsg,
 588                                 c.ID,
 589                                 NewField(fieldData, []byte("You are permanently banned on this server")),
 590                                 NewField(fieldChatOptions, []byte{0, 0}),
 591                         )
 592                         time.Sleep(1 * time.Second)
 593                         return nil
 594                 } else if time.Now().Before(*banUntil) {
 595                         s.outbox <- *NewTransaction(
 596                                 tranServerMsg,
 597                                 c.ID,
 598                                 NewField(fieldData, []byte("You are temporarily banned on this server")),
 599                                 NewField(fieldChatOptions, []byte{0, 0}),
 600                         )
 601                         time.Sleep(1 * time.Second)
 602                         return nil
 603                 }
 604
 605         }
 606         defer c.Disconnect()
 607
 608         encodedLogin := clientLogin.GetField(fieldUserLogin).Data
 609         encodedPassword := clientLogin.GetField(fieldUserPassword).Data
 610         c.Version = clientLogin.GetField(fieldVersion).Data
 611
 612         var login string
 613         for _, char := range encodedLogin {
 614                 login += string(rune(255 - uint(char)))
 615         }
 616         if login == "" {
 617                 login = GuestAccount
 618         }
 619
 620         c.logger = s.Logger.With("remoteAddr", remoteAddr, "login", login)
 621
 622         // If authentication fails, send error reply and close connection
 623         if !c.Authenticate(login, encodedPassword) {
 624                 t := c.NewErrReply(&clientLogin, "Incorrect login.")
 625                 b, err := t.MarshalBinary()
 626                 if err != nil {
 627                         return err
 628                 }
 629                 if _, err := rwc.Write(b); err != nil {
 630                         return err
 631                 }
 632
 633                 c.logger.Infow("Login failed", "clientVersion", fmt.Sprintf("%x", c.Version))
 634
 635                 return nil
 636         }
 637
 638         if clientLogin.GetField(fieldUserIconID).Data != nil {
 639                 c.Icon = clientLogin.GetField(fieldUserIconID).Data
 640         }
 641
 642         c.Account = c.Server.Accounts[login]
 643
 644         if clientLogin.GetField(fieldUserName).Data != nil {
 645                 if c.Authorize(accessAnyName) {
 646                         c.UserName = clientLogin.GetField(fieldUserName).Data
 647                 } else {
 648                         c.UserName = []byte(c.Account.Name)
 649                 }
 650         }
 651
 652         if c.Authorize(accessDisconUser) {
 653                 c.Flags = []byte{0, 2}
 654         }
 655
 656         s.outbox <- c.NewReply(&clientLogin,
 657                 NewField(fieldVersion, []byte{0x00, 0xbe}),
 658                 NewField(fieldCommunityBannerID, []byte{0, 0}),
 659                 NewField(fieldServerName, []byte(s.Config.Name)),
 660         )
 661
 662         // Send user access privs so client UI knows how to behave
 663         c.Server.outbox <- *NewTransaction(tranUserAccess, c.ID, NewField(fieldUserAccess, c.Account.Access[:]))
 664
 665         // Accounts with accessNoAgreement do not receive the server agreement on login.  The behavior is different between
 666         // client versions.  For 1.2.3 client, we do not send tranShowAgreement.  For other client versions, we send
 667         // tranShowAgreement but with the NoServerAgreement field set to 1.
 668         if c.Authorize(accessNoAgreement) {
 669                 // If client version is nil, then the client uses the 1.2.3 login behavior
 670                 if c.Version != nil {
 671                         c.Server.outbox <- *NewTransaction(tranShowAgreement, c.ID, NewField(fieldNoServerAgreement, []byte{1}))
 672                 }
 673         } else {
 674                 c.Server.outbox <- *NewTransaction(tranShowAgreement, c.ID, NewField(fieldData, s.Agreement))
 675         }
 676
 677         // Used simplified hotline v1.2.3 login flow for clients that do not send login info in tranAgreed
 678         // TODO: figure out a generalized solution that doesn't require playing whack-a-mole for specific client versions
 679         if c.Version == nil || bytes.Equal(c.Version, nostalgiaVersion) || bytes.Equal(c.Version, frogblastVersion) || bytes.Equal(c.Version, obsessionVersion) {
 680                 c.Agreed = true
 681                 c.logger = c.logger.With("name", string(c.UserName))
 682                 c.logger.Infow("Login successful", "clientVersion", fmt.Sprintf("%v", func() int { i, _ := byteToInt(c.Version); return i }()))
 683
 684                 for _, t := range c.notifyOthers(
 685                         *NewTransaction(
 686                                 tranNotifyChangeUser, nil,
 687                                 NewField(fieldUserName, c.UserName),
 688                                 NewField(fieldUserID, *c.ID),
 689                                 NewField(fieldUserIconID, c.Icon),
 690                                 NewField(fieldUserFlags, c.Flags),
 691                         ),
 692                 ) {
 693                         c.Server.outbox <- t
 694                 }
 695         }
 696
 697         c.Server.Stats.ConnectionCounter += 1
 698         if len(s.Clients) > c.Server.Stats.ConnectionPeak {
 699                 c.Server.Stats.ConnectionPeak = len(s.Clients)
 700         }
 701
 702         // Scan for new transactions and handle them as they come in.
 703         for scanner.Scan() {
 704                 // Make a new []byte slice and copy the scanner bytes to it.  This is critical to avoid a data race as the
 705                 // scanner re-uses the buffer for subsequent scans.
 706                 buf := make([]byte, len(scanner.Bytes()))
 707                 copy(buf, scanner.Bytes())
 708
 709                 var t Transaction
 710                 if _, err := t.Write(buf); err != nil {
 711                         return err
 712                 }
 713
 714                 if err := c.handleTransaction(t); err != nil {
 715                         c.logger.Errorw("Error handling transaction", "err", err)
 716                 }
 717         }
 718         return nil
 719 }
 720
 721 func (s *Server) NewPrivateChat(cc *ClientConn) []byte {
 722         s.PrivateChatsMu.Lock()
 723         defer s.PrivateChatsMu.Unlock()
 724
 725         randID := make([]byte, 4)
 726         rand.Read(randID)
 727         data := binary.BigEndian.Uint32(randID[:])
 728
 729         s.PrivateChats[data] = &PrivateChat{
 730                 ClientConn: make(map[uint16]*ClientConn),
 731         }
 732         s.PrivateChats[data].ClientConn[cc.uint16ID()] = cc
 733
 734         return randID
 735 }
 736
 737 const dlFldrActionSendFile = 1
 738 const dlFldrActionResumeFile = 2
 739 const dlFldrActionNextFile = 3
 740
 741 // handleFileTransfer receives a client net.Conn from the file transfer server, performs the requested transfer type, then closes the connection
 742 func (s *Server) handleFileTransfer(ctx context.Context, rwc io.ReadWriter) error {
 743         defer dontPanic(s.Logger)
 744
 745         txBuf := make([]byte, 16)
 746         if _, err := io.ReadFull(rwc, txBuf); err != nil {
 747                 return err
 748         }
 749
 750         var t transfer
 751         if _, err := t.Write(txBuf); err != nil {
 752                 return err
 753         }
 754
 755         defer func() {
 756                 s.mux.Lock()
 757                 delete(s.fileTransfers, t.ReferenceNumber)
 758                 s.mux.Unlock()
 759
 760                 // Wait a few seconds before closing the connection: this is a workaround for problems
 761                 // observed with Windows clients where the client must initiate close of the TCP connection before
 762                 // the server does.  This is gross and seems unnecessary.  TODO: Revisit?
 763                 time.Sleep(3 * time.Second)
 764         }()
 765
 766         s.mux.Lock()
 767         fileTransfer, ok := s.fileTransfers[t.ReferenceNumber]
 768         s.mux.Unlock()
 769         if !ok {
 770                 return errors.New("invalid transaction ID")
 771         }
 772
 773         defer func() {
 774                 fileTransfer.ClientConn.transfersMU.Lock()
 775                 delete(fileTransfer.ClientConn.transfers[fileTransfer.Type], t.ReferenceNumber)
 776                 fileTransfer.ClientConn.transfersMU.Unlock()
 777         }()
 778
 779         rLogger := s.Logger.With(
 780                 "remoteAddr", ctx.Value(contextKeyReq).(requestCtx).remoteAddr,
 781                 "login", fileTransfer.ClientConn.Account.Login,
 782                 "name", string(fileTransfer.ClientConn.UserName),
 783         )
 784
 785         fullPath, err := readPath(s.Config.FileRoot, fileTransfer.FilePath, fileTransfer.FileName)
 786         if err != nil {
 787                 return err
 788         }
 789
 790         switch fileTransfer.Type {
 791         case bannerDownload:
 792                 if err := s.bannerDownload(rwc); err != nil {
 793                         return err
 794                 }
 795         case FileDownload:
 796                 s.Stats.DownloadCounter += 1
 797                 s.Stats.DownloadsInProgress += 1
 798                 defer func() {
 799                         s.Stats.DownloadsInProgress -= 1
 800                 }()
 801
 802                 var dataOffset int64
 803                 if fileTransfer.fileResumeData != nil {
 804                         dataOffset = int64(binary.BigEndian.Uint32(fileTransfer.fileResumeData.ForkInfoList[0].DataSize[:]))
 805                 }
 806
 807                 fw, err := newFileWrapper(s.FS, fullPath, 0)
 808                 if err != nil {
 809                         return err
 810                 }
 811
 812                 rLogger.Infow("File download started", "filePath", fullPath)
 813
 814                 // if file transfer options are included, that means this is a "quick preview" request from a 1.5+ client
 815                 if fileTransfer.options == nil {
 816                         // Start by sending flat file object to client
 817                         if _, err := rwc.Write(fw.ffo.BinaryMarshal()); err != nil {
 818                                 return err
 819                         }
 820                 }
 821
 822                 file, err := fw.dataForkReader()
 823                 if err != nil {
 824                         return err
 825                 }
 826
 827                 br := bufio.NewReader(file)
 828                 if _, err := br.Discard(int(dataOffset)); err != nil {
 829                         return err
 830                 }
 831
 832                 if _, err = io.Copy(rwc, io.TeeReader(br, fileTransfer.bytesSentCounter)); err != nil {
 833                         return err
 834                 }
 835
 836                 // if the client requested to resume transfer, do not send the resource fork header, or it will be appended into the fileWrapper data
 837                 if fileTransfer.fileResumeData == nil {
 838                         err = binary.Write(rwc, binary.BigEndian, fw.rsrcForkHeader())
 839                         if err != nil {
 840                                 return err
 841                         }
 842                 }
 843
 844                 rFile, err := fw.rsrcForkFile()
 845                 if err != nil {
 846                         return nil
 847                 }
 848
 849                 if _, err = io.Copy(rwc, io.TeeReader(rFile, fileTransfer.bytesSentCounter)); err != nil {
 850                         return err
 851                 }
 852
 853         case FileUpload:
 854                 s.Stats.UploadCounter += 1
 855                 s.Stats.UploadsInProgress += 1
 856                 defer func() { s.Stats.UploadsInProgress -= 1 }()
 857
 858                 var file *os.File
 859
 860                 // A file upload has three possible cases:
 861                 // 1) Upload a new file
 862                 // 2) Resume a partially transferred file
 863                 // 3) Replace a fully uploaded file
 864                 //  We have to infer which case applies by inspecting what is already on the filesystem
 865
 866                 // 1) Check for existing file:
 867                 _, err = os.Stat(fullPath)
 868                 if err == nil {
 869                         return errors.New("existing file found at " + fullPath)
 870                 }
 871                 if errors.Is(err, fs.ErrNotExist) {
 872                         // If not found, open or create a new .incomplete file
 873                         file, err = os.OpenFile(fullPath+incompleteFileSuffix, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0644)
 874                         if err != nil {
 875                                 return err
 876                         }
 877                 }
 878
 879                 f, err := newFileWrapper(s.FS, fullPath, 0)
 880                 if err != nil {
 881                         return err
 882                 }
 883
 884                 rLogger.Infow("File upload started", "dstFile", fullPath)
 885
 886                 rForkWriter := io.Discard
 887                 iForkWriter := io.Discard
 888                 if s.Config.PreserveResourceForks {
 889                         rForkWriter, err = f.rsrcForkWriter()
 890                         if err != nil {
 891                                 return err
 892                         }
 893
 894                         iForkWriter, err = f.infoForkWriter()
 895                         if err != nil {
 896                                 return err
 897                         }
 898                 }
 899
 900                 if err := receiveFile(rwc, file, rForkWriter, iForkWriter, fileTransfer.bytesSentCounter); err != nil {
 901                         s.Logger.Error(err)
 902                 }
 903
 904                 if err := file.Close(); err != nil {
 905                         return err
 906                 }
 907
 908                 if err := s.FS.Rename(fullPath+".incomplete", fullPath); err != nil {
 909                         return err
 910                 }
 911
 912                 rLogger.Infow("File upload complete", "dstFile", fullPath)
 913
 914         case FolderDownload:
 915                 s.Stats.DownloadCounter += 1
 916                 s.Stats.DownloadsInProgress += 1
 917                 defer func() { s.Stats.DownloadsInProgress -= 1 }()
 918
 919                 // Folder Download flow:
 920                 // 1. Get filePath from the transfer
 921                 // 2. Iterate over files
 922                 // 3. For each fileWrapper:
 923                 //       Send fileWrapper header to client
 924                 // The client can reply in 3 ways:
 925                 //
 926                 // 1. If type is an odd number (unknown type?), or fileWrapper download for the current fileWrapper is completed:
 927                 //              client sends []byte{0x00, 0x03} to tell the server to continue to the next fileWrapper
 928                 //
 929                 // 2. If download of a fileWrapper is to be resumed:
 930                 //              client sends:
 931                 //                      []byte{0x00, 0x02} // download folder action
 932                 //                      [2]byte // Resume data size
 933                 //                      []byte fileWrapper resume data (see myField_FileResumeData)
 934                 //
 935                 // 3. Otherwise, download of the fileWrapper is requested and client sends []byte{0x00, 0x01}
 936                 //
 937                 // When download is requested (case 2 or 3), server replies with:
 938                 //                      [4]byte - fileWrapper size
 939                 //                      []byte  - Flattened File Object
 940                 //
 941                 // After every fileWrapper download, client could request next fileWrapper with:
 942                 //                      []byte{0x00, 0x03}
 943                 //
 944                 // This notifies the server to send the next item header
 945
 946                 basePathLen := len(fullPath)
 947
 948                 rLogger.Infow("Start folder download", "path", fullPath)
 949
 950                 nextAction := make([]byte, 2)
 951                 if _, err := io.ReadFull(rwc, nextAction); err != nil {
 952                         return err
 953                 }
 954
 955                 i := 0
 956                 err = filepath.Walk(fullPath+"/", func(path string, info os.FileInfo, err error) error {
 957                         s.Stats.DownloadCounter += 1
 958                         i += 1
 959
 960                         if err != nil {
 961                                 return err
 962                         }
 963
 964                         // skip dot files
 965                         if strings.HasPrefix(info.Name(), ".") {
 966                                 return nil
 967                         }
 968
 969                         hlFile, err := newFileWrapper(s.FS, path, 0)
 970                         if err != nil {
 971                                 return err
 972                         }
 973
 974                         subPath := path[basePathLen+1:]
 975                         rLogger.Debugw("Sending fileheader", "i", i, "path", path, "fullFilePath", fullPath, "subPath", subPath, "IsDir", info.IsDir())
 976
 977                         if i == 1 {
 978                                 return nil
 979                         }
 980
 981                         fileHeader := NewFileHeader(subPath, info.IsDir())
 982
 983                         // Send the fileWrapper header to client
 984                         if _, err := rwc.Write(fileHeader.Payload()); err != nil {
 985                                 s.Logger.Errorf("error sending file header: %v", err)
 986                                 return err
 987                         }
 988
 989                         // Read the client's Next Action request
 990                         if _, err := io.ReadFull(rwc, nextAction); err != nil {
 991                                 return err
 992                         }
 993
 994                         rLogger.Debugw("Client folder download action", "action", fmt.Sprintf("%X", nextAction[0:2]))
 995
 996                         var dataOffset int64
 997
 998                         switch nextAction[1] {
 999                         case dlFldrActionResumeFile:
1000                                 // get size of resumeData
1001                                 resumeDataByteLen := make([]byte, 2)
1002                                 if _, err := io.ReadFull(rwc, resumeDataByteLen); err != nil {
1003                                         return err
1004                                 }
1005
1006                                 resumeDataLen := binary.BigEndian.Uint16(resumeDataByteLen)
1007                                 resumeDataBytes := make([]byte, resumeDataLen)
1008                                 if _, err := io.ReadFull(rwc, resumeDataBytes); err != nil {
1009                                         return err
1010                                 }
1011
1012                                 var frd FileResumeData
1013                                 if err := frd.UnmarshalBinary(resumeDataBytes); err != nil {
1014                                         return err
1015                                 }
1016                                 dataOffset = int64(binary.BigEndian.Uint32(frd.ForkInfoList[0].DataSize[:]))
1017                         case dlFldrActionNextFile:
1018                                 // client asked to skip this file
1019                                 return nil
1020                         }
1021
1022                         if info.IsDir() {
1023                                 return nil
1024                         }
1025
1026                         rLogger.Infow("File download started",
1027                                 "fileName", info.Name(),
1028                                 "TransferSize", fmt.Sprintf("%x", hlFile.ffo.TransferSize(dataOffset)),
1029                         )
1030
1031                         // Send file size to client
1032                         if _, err := rwc.Write(hlFile.ffo.TransferSize(dataOffset)); err != nil {
1033                                 s.Logger.Error(err)
1034                                 return err
1035                         }
1036
1037                         // Send ffo bytes to client
1038                         if _, err := rwc.Write(hlFile.ffo.BinaryMarshal()); err != nil {
1039                                 s.Logger.Error(err)
1040                                 return err
1041                         }
1042
1043                         file, err := s.FS.Open(path)
1044                         if err != nil {
1045                                 return err
1046                         }
1047
1048                         // wr := bufio.NewWriterSize(rwc, 1460)
1049                         if _, err = io.Copy(rwc, io.TeeReader(file, fileTransfer.bytesSentCounter)); err != nil {
1050                                 return err
1051                         }
1052
1053                         if nextAction[1] != 2 && hlFile.ffo.FlatFileHeader.ForkCount[1] == 3 {
1054                                 err = binary.Write(rwc, binary.BigEndian, hlFile.rsrcForkHeader())
1055                                 if err != nil {
1056                                         return err
1057                                 }
1058
1059                                 rFile, err := hlFile.rsrcForkFile()
1060                                 if err != nil {
1061                                         return err
1062                                 }
1063
1064                                 if _, err = io.Copy(rwc, io.TeeReader(rFile, fileTransfer.bytesSentCounter)); err != nil {
1065                                         return err
1066                                 }
1067                         }
1068
1069                         // Read the client's Next Action request.  This is always 3, I think?
1070                         if _, err := io.ReadFull(rwc, nextAction); err != nil {
1071                                 return err
1072                         }
1073
1074                         return nil
1075                 })
1076
1077                 if err != nil {
1078                         return err
1079                 }
1080
1081         case FolderUpload:
1082                 s.Stats.UploadCounter += 1
1083                 s.Stats.UploadsInProgress += 1
1084                 defer func() { s.Stats.UploadsInProgress -= 1 }()
1085                 rLogger.Infow(
1086                         "Folder upload started",
1087                         "dstPath", fullPath,
1088                         "TransferSize", binary.BigEndian.Uint32(fileTransfer.TransferSize),
1089                         "FolderItemCount", fileTransfer.FolderItemCount,
1090                 )
1091
1092                 // Check if the target folder exists.  If not, create it.
1093                 if _, err := s.FS.Stat(fullPath); os.IsNotExist(err) {
1094                         if err := s.FS.Mkdir(fullPath, 0777); err != nil {
1095                                 return err
1096                         }
1097                 }
1098
1099                 // Begin the folder upload flow by sending the "next file action" to client
1100                 if _, err := rwc.Write([]byte{0, dlFldrActionNextFile}); err != nil {
1101                         return err
1102                 }
1103
1104                 fileSize := make([]byte, 4)
1105
1106                 for i := 0; i < fileTransfer.ItemCount(); i++ {
1107                         s.Stats.UploadCounter += 1
1108
1109                         var fu folderUpload
1110                         if _, err := io.ReadFull(rwc, fu.DataSize[:]); err != nil {
1111                                 return err
1112                         }
1113                         if _, err := io.ReadFull(rwc, fu.IsFolder[:]); err != nil {
1114                                 return err
1115                         }
1116                         if _, err := io.ReadFull(rwc, fu.PathItemCount[:]); err != nil {
1117                                 return err
1118                         }
1119
1120                         fu.FileNamePath = make([]byte, binary.BigEndian.Uint16(fu.DataSize[:])-4) // -4 to subtract the path separator bytes
1121
1122                         if _, err := io.ReadFull(rwc, fu.FileNamePath); err != nil {
1123                                 return err
1124                         }
1125
1126                         rLogger.Infow(
1127                                 "Folder upload continued",
1128                                 "FormattedPath", fu.FormattedPath(),
1129                                 "IsFolder", fmt.Sprintf("%x", fu.IsFolder),
1130                                 "PathItemCount", binary.BigEndian.Uint16(fu.PathItemCount[:]),
1131                         )
1132
1133                         if fu.IsFolder == [2]byte{0, 1} {
1134                                 if _, err := os.Stat(filepath.Join(fullPath, fu.FormattedPath())); os.IsNotExist(err) {
1135                                         if err := os.Mkdir(filepath.Join(fullPath, fu.FormattedPath()), 0777); err != nil {
1136                                                 return err
1137                                         }
1138                                 }
1139
1140                                 // Tell client to send next file
1141                                 if _, err := rwc.Write([]byte{0, dlFldrActionNextFile}); err != nil {
1142                                         return err
1143                                 }
1144                         } else {
1145                                 nextAction := dlFldrActionSendFile
1146
1147                                 // Check if we have the full file already.  If so, send dlFldrAction_NextFile to client to skip.
1148                                 _, err = os.Stat(filepath.Join(fullPath, fu.FormattedPath()))
1149                                 if err != nil && !errors.Is(err, fs.ErrNotExist) {
1150                                         return err
1151                                 }
1152                                 if err == nil {
1153                                         nextAction = dlFldrActionNextFile
1154                                 }
1155
1156                                 //  Check if we have a partial file already.  If so, send dlFldrAction_ResumeFile to client to resume upload.
1157                                 incompleteFile, err := os.Stat(filepath.Join(fullPath, fu.FormattedPath()+incompleteFileSuffix))
1158                                 if err != nil && !errors.Is(err, fs.ErrNotExist) {
1159                                         return err
1160                                 }
1161                                 if err == nil {
1162                                         nextAction = dlFldrActionResumeFile
1163                                 }
1164
1165                                 if _, err := rwc.Write([]byte{0, uint8(nextAction)}); err != nil {
1166                                         return err
1167                                 }
1168
1169                                 switch nextAction {
1170                                 case dlFldrActionNextFile:
1171                                         continue
1172                                 case dlFldrActionResumeFile:
1173                                         offset := make([]byte, 4)
1174                                         binary.BigEndian.PutUint32(offset, uint32(incompleteFile.Size()))
1175
1176                                         file, err := os.OpenFile(fullPath+"/"+fu.FormattedPath()+incompleteFileSuffix, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
1177                                         if err != nil {
1178                                                 return err
1179                                         }
1180
1181                                         fileResumeData := NewFileResumeData([]ForkInfoList{*NewForkInfoList(offset)})
1182
1183                                         b, _ := fileResumeData.BinaryMarshal()
1184
1185                                         bs := make([]byte, 2)
1186                                         binary.BigEndian.PutUint16(bs, uint16(len(b)))
1187
1188                                         if _, err := rwc.Write(append(bs, b...)); err != nil {
1189                                                 return err
1190                                         }
1191
1192                                         if _, err := io.ReadFull(rwc, fileSize); err != nil {
1193                                                 return err
1194                                         }
1195
1196                                         if err := receiveFile(rwc, file, ioutil.Discard, ioutil.Discard, fileTransfer.bytesSentCounter); err != nil {
1197                                                 s.Logger.Error(err)
1198                                         }
1199
1200                                         err = os.Rename(fullPath+"/"+fu.FormattedPath()+".incomplete", fullPath+"/"+fu.FormattedPath())
1201                                         if err != nil {
1202                                                 return err
1203                                         }
1204
1205                                 case dlFldrActionSendFile:
1206                                         if _, err := io.ReadFull(rwc, fileSize); err != nil {
1207                                                 return err
1208                                         }
1209
1210                                         filePath := filepath.Join(fullPath, fu.FormattedPath())
1211
1212                                         hlFile, err := newFileWrapper(s.FS, filePath, 0)
1213                                         if err != nil {
1214                                                 return err
1215                                         }
1216
1217                                         rLogger.Infow("Starting file transfer", "path", filePath, "fileNum", i+1, "fileSize", binary.BigEndian.Uint32(fileSize))
1218
1219                                         incWriter, err := hlFile.incFileWriter()
1220                                         if err != nil {
1221                                                 return err
1222                                         }
1223
1224                                         rForkWriter := io.Discard
1225                                         iForkWriter := io.Discard
1226                                         if s.Config.PreserveResourceForks {
1227                                                 iForkWriter, err = hlFile.infoForkWriter()
1228                                                 if err != nil {
1229                                                         return err
1230                                                 }
1231
1232                                                 rForkWriter, err = hlFile.rsrcForkWriter()
1233                                                 if err != nil {
1234                                                         return err
1235                                                 }
1236                                         }
1237                                         if err := receiveFile(rwc, incWriter, rForkWriter, iForkWriter, fileTransfer.bytesSentCounter); err != nil {
1238                                                 return err
1239                                         }
1240
1241                                         if err := os.Rename(filePath+".incomplete", filePath); err != nil {
1242                                                 return err
1243                                         }
1244                                 }
1245
1246                                 // Tell client to send next fileWrapper
1247                                 if _, err := rwc.Write([]byte{0, dlFldrActionNextFile}); err != nil {
1248                                         return err
1249                                 }
1250                         }
1251                 }
1252                 rLogger.Infof("Folder upload complete")
1253         }
1254
1255         return nil
1256 }