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