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 heildrun = []byte{0, 0x97}
  40
  41 var obsessionVersion = []byte{0xbe, 0x00} // version ID used by the Obsession client
  42
  43 type Server struct {
  44         Port          int
  45         Accounts      map[string]*Account
  46         Agreement     []byte
  47         Clients       map[uint16]*ClientConn
  48         fileTransfers map[[4]byte]*FileTransfer
  49
  50         Config    *Config
  51         ConfigDir string
  52         Logger    *zap.SugaredLogger
  53
  54         PrivateChatsMu sync.Mutex
  55         PrivateChats   map[uint32]*PrivateChat
  56
  57         NextGuestID   *uint16
  58         TrackerPassID [4]byte
  59
  60         StatsMu sync.Mutex
  61         Stats   *Stats
  62
  63         FS FileStore // Storage backend to use for File storage
  64
  65         outbox chan Transaction
  66         mux    sync.Mutex
  67
  68         threadedNewsMux sync.Mutex
  69         ThreadedNews    *ThreadedNews
  70
  71         flatNewsMux sync.Mutex
  72         FlatNews    []byte
  73
  74         banListMU sync.Mutex
  75         banList   map[string]*time.Time
  76 }
  77
  78 func (s *Server) CurrentStats() Stats {
  79         s.StatsMu.Lock()
  80         defer s.StatsMu.Unlock()
  81
  82         stats := s.Stats
  83         stats.CurrentlyConnected = len(s.Clients)
  84
  85         return *stats
  86 }
  87
  88 type PrivateChat struct {
  89         Subject    string
  90         ClientConn map[uint16]*ClientConn
  91 }
  92
  93 func (s *Server) ListenAndServe(ctx context.Context, cancelRoot context.CancelFunc) error {
  94         s.Logger.Infow("Hotline server started",
  95                 "version", VERSION,
  96                 "API port", fmt.Sprintf(":%v", s.Port),
  97                 "Transfer port", fmt.Sprintf(":%v", s.Port+1),
  98         )
  99
 100         var wg sync.WaitGroup
 101
 102         wg.Add(1)
 103         go func() {
 104                 ln, err := net.Listen("tcp", fmt.Sprintf("%s:%v", "", s.Port))
 105                 if err != nil {
 106                         s.Logger.Fatal(err)
 107                 }
 108
 109                 s.Logger.Fatal(s.Serve(ctx, ln))
 110         }()
 111
 112         wg.Add(1)
 113         go func() {
 114                 ln, err := net.Listen("tcp", fmt.Sprintf("%s:%v", "", s.Port+1))
 115                 if err != nil {
 116                         s.Logger.Fatal(err)
 117
 118                 }
 119
 120                 s.Logger.Fatal(s.ServeFileTransfers(ctx, ln))
 121         }()
 122
 123         wg.Wait()
 124
 125         return nil
 126 }
 127
 128 func (s *Server) ServeFileTransfers(ctx context.Context, ln net.Listener) error {
 129         for {
 130                 conn, err := ln.Accept()
 131                 if err != nil {
 132                         return err
 133                 }
 134
 135                 go func() {
 136                         defer func() { _ = conn.Close() }()
 137
 138                         err = s.handleFileTransfer(
 139                                 context.WithValue(ctx, contextKeyReq, requestCtx{
 140                                         remoteAddr: conn.RemoteAddr().String(),
 141                                 }),
 142                                 conn,
 143                         )
 144
 145                         if err != nil {
 146                                 s.Logger.Errorw("file transfer error", "reason", err)
 147                         }
 148                 }()
 149         }
 150 }
 151
 152 func (s *Server) sendTransaction(t Transaction) error {
 153         clientID, err := byteToInt(*t.clientID)
 154         if err != nil {
 155                 return err
 156         }
 157
 158         s.mux.Lock()
 159         client := s.Clients[uint16(clientID)]
 160         s.mux.Unlock()
 161         if client == nil {
 162                 return fmt.Errorf("invalid client id %v", *t.clientID)
 163         }
 164
 165         b, err := t.MarshalBinary()
 166         if err != nil {
 167                 return err
 168         }
 169
 170         _, err = client.Connection.Write(b)
 171         if err != nil {
 172                 return err
 173         }
 174
 175         return nil
 176 }
 177
 178 func (s *Server) processOutbox() {
 179         for {
 180                 t := <-s.outbox
 181                 go func() {
 182                         if err := s.sendTransaction(t); err != nil {
 183                                 s.Logger.Errorw("error sending transaction", "err", err)
 184                         }
 185                 }()
 186         }
 187 }
 188
 189 func (s *Server) Serve(ctx context.Context, ln net.Listener) error {
 190         go s.processOutbox()
 191
 192         for {
 193                 conn, err := ln.Accept()
 194                 if err != nil {
 195                         s.Logger.Errorw("error accepting connection", "err", err)
 196                 }
 197                 connCtx := context.WithValue(ctx, contextKeyReq, requestCtx{
 198                         remoteAddr: conn.RemoteAddr().String(),
 199                 })
 200
 201                 go func() {
 202                         s.Logger.Infow("Connection established", "RemoteAddr", conn.RemoteAddr())
 203
 204                         defer conn.Close()
 205                         if err := s.handleNewConnection(connCtx, conn, conn.RemoteAddr().String()); err != nil {
 206                                 if err == io.EOF {
 207                                         s.Logger.Infow("Client disconnected", "RemoteAddr", conn.RemoteAddr())
 208                                 } else {
 209                                         s.Logger.Errorw("error serving request", "RemoteAddr", conn.RemoteAddr(), "err", err)
 210                                 }
 211                         }
 212                 }()
 213         }
 214 }
 215
 216 const (
 217         agreementFile = "Agreement.txt"
 218 )
 219
 220 // NewServer constructs a new Server from a config dir
 221 func NewServer(configDir string, netPort int, logger *zap.SugaredLogger, FS FileStore) (*Server, error) {
 222         server := Server{
 223                 Port:          netPort,
 224                 Accounts:      make(map[string]*Account),
 225                 Config:        new(Config),
 226                 Clients:       make(map[uint16]*ClientConn),
 227                 fileTransfers: make(map[[4]byte]*FileTransfer),
 228                 PrivateChats:  make(map[uint32]*PrivateChat),
 229                 ConfigDir:     configDir,
 230                 Logger:        logger,
 231                 NextGuestID:   new(uint16),
 232                 outbox:        make(chan Transaction),
 233                 Stats:         &Stats{Since: time.Now()},
 234                 ThreadedNews:  &ThreadedNews{},
 235                 FS:            FS,
 236                 banList:       make(map[string]*time.Time),
 237         }
 238
 239         var err error
 240
 241         // generate a new random passID for tracker registration
 242         if _, err := rand.Read(server.TrackerPassID[:]); err != nil {
 243                 return nil, err
 244         }
 245
 246         server.Agreement, err = os.ReadFile(filepath.Join(configDir, agreementFile))
 247         if err != nil {
 248                 return nil, err
 249         }
 250
 251         if server.FlatNews, err = os.ReadFile(filepath.Join(configDir, "MessageBoard.txt")); err != nil {
 252                 return nil, err
 253         }
 254
 255         // try to load the ban list, but ignore errors as this file may not be present or may be empty
 256         _ = server.loadBanList(filepath.Join(configDir, "Banlist.yaml"))
 257
 258         if err := server.loadThreadedNews(filepath.Join(configDir, "ThreadedNews.yaml")); err != nil {
 259                 return nil, err
 260         }
 261
 262         if err := server.loadConfig(filepath.Join(configDir, "config.yaml")); err != nil {
 263                 return nil, err
 264         }
 265
 266         if err := server.loadAccounts(filepath.Join(configDir, "Users/")); err != nil {
 267                 return nil, err
 268         }
 269
 270         server.Config.FileRoot = filepath.Join(configDir, "Files")
 271
 272         *server.NextGuestID = 1
 273
 274         if server.Config.EnableTrackerRegistration {
 275                 server.Logger.Infow(
 276                         "Tracker registration enabled",
 277                         "frequency", fmt.Sprintf("%vs", trackerUpdateFrequency),
 278                         "trackers", server.Config.Trackers,
 279                 )
 280
 281                 go func() {
 282                         for {
 283                                 tr := &TrackerRegistration{
 284                                         UserCount:   server.userCount(),
 285                                         PassID:      server.TrackerPassID[:],
 286                                         Name:        server.Config.Name,
 287                                         Description: server.Config.Description,
 288                                 }
 289                                 binary.BigEndian.PutUint16(tr.Port[:], uint16(server.Port))
 290                                 for _, t := range server.Config.Trackers {
 291                                         if err := register(t, tr); err != nil {
 292                                                 server.Logger.Errorw("unable to register with tracker %v", "error", err)
 293                                         }
 294                                         server.Logger.Debugw("Sent Tracker registration", "addr", t)
 295                                 }
 296
 297                                 time.Sleep(trackerUpdateFrequency * time.Second)
 298                         }
 299                 }()
 300         }
 301
 302         // Start Client Keepalive go routine
 303         go server.keepaliveHandler()
 304
 305         return &server, nil
 306 }
 307
 308 func (s *Server) userCount() int {
 309         s.mux.Lock()
 310         defer s.mux.Unlock()
 311
 312         return len(s.Clients)
 313 }
 314
 315 func (s *Server) keepaliveHandler() {
 316         for {
 317                 time.Sleep(idleCheckInterval * time.Second)
 318                 s.mux.Lock()
 319
 320                 for _, c := range s.Clients {
 321                         c.IdleTime += idleCheckInterval
 322                         if c.IdleTime > userIdleSeconds && !c.Idle {
 323                                 c.Idle = true
 324
 325                                 flagBitmap := big.NewInt(int64(binary.BigEndian.Uint16(c.Flags)))
 326                                 flagBitmap.SetBit(flagBitmap, userFlagAway, 1)
 327                                 binary.BigEndian.PutUint16(c.Flags, uint16(flagBitmap.Int64()))
 328
 329                                 c.sendAll(
 330                                         tranNotifyChangeUser,
 331                                         NewField(fieldUserID, *c.ID),
 332                                         NewField(fieldUserFlags, c.Flags),
 333                                         NewField(fieldUserName, c.UserName),
 334                                         NewField(fieldUserIconID, c.Icon),
 335                                 )
 336                         }
 337                 }
 338                 s.mux.Unlock()
 339         }
 340 }
 341
 342 func (s *Server) writeBanList() error {
 343         s.banListMU.Lock()
 344         defer s.banListMU.Unlock()
 345
 346         out, err := yaml.Marshal(s.banList)
 347         if err != nil {
 348                 return err
 349         }
 350         err = ioutil.WriteFile(
 351                 filepath.Join(s.ConfigDir, "Banlist.yaml"),
 352                 out,
 353                 0666,
 354         )
 355         return err
 356 }
 357
 358 func (s *Server) writeThreadedNews() error {
 359         s.threadedNewsMux.Lock()
 360         defer s.threadedNewsMux.Unlock()
 361
 362         out, err := yaml.Marshal(s.ThreadedNews)
 363         if err != nil {
 364                 return err
 365         }
 366         err = s.FS.WriteFile(
 367                 filepath.Join(s.ConfigDir, "ThreadedNews.yaml"),
 368                 out,
 369                 0666,
 370         )
 371         return err
 372 }
 373
 374 func (s *Server) NewClientConn(conn io.ReadWriteCloser, remoteAddr string) *ClientConn {
 375         s.mux.Lock()
 376         defer s.mux.Unlock()
 377
 378         clientConn := &ClientConn{
 379                 ID:         &[]byte{0, 0},
 380                 Icon:       []byte{0, 0},
 381                 Flags:      []byte{0, 0},
 382                 UserName:   []byte{},
 383                 Connection: conn,
 384                 Server:     s,
 385                 Version:    []byte{},
 386                 AutoReply:  []byte{},
 387                 transfers:  map[int]map[[4]byte]*FileTransfer{},
 388                 Agreed:     false,
 389                 RemoteAddr: remoteAddr,
 390         }
 391         clientConn.transfers = map[int]map[[4]byte]*FileTransfer{
 392                 FileDownload:   {},
 393                 FileUpload:     {},
 394                 FolderDownload: {},
 395                 FolderUpload:   {},
 396                 bannerDownload: {},
 397         }
 398
 399         *s.NextGuestID++
 400         ID := *s.NextGuestID
 401
 402         binary.BigEndian.PutUint16(*clientConn.ID, ID)
 403         s.Clients[ID] = clientConn
 404
 405         return clientConn
 406 }
 407
 408 // NewUser creates a new user account entry in the server map and config file
 409 func (s *Server) NewUser(login, name, password string, access accessBitmap) error {
 410         s.mux.Lock()
 411         defer s.mux.Unlock()
 412
 413         account := Account{
 414                 Login:    login,
 415                 Name:     name,
 416                 Password: hashAndSalt([]byte(password)),
 417                 Access:   access,
 418         }
 419         out, err := yaml.Marshal(&account)
 420         if err != nil {
 421                 return err
 422         }
 423         s.Accounts[login] = &account
 424
 425         return s.FS.WriteFile(filepath.Join(s.ConfigDir, "Users", login+".yaml"), out, 0666)
 426 }
 427
 428 func (s *Server) UpdateUser(login, newLogin, name, password string, access accessBitmap) error {
 429         s.mux.Lock()
 430         defer s.mux.Unlock()
 431
 432         // update renames the user login
 433         if login != newLogin {
 434                 err := os.Rename(filepath.Join(s.ConfigDir, "Users", login+".yaml"), filepath.Join(s.ConfigDir, "Users", newLogin+".yaml"))
 435                 if err != nil {
 436                         return err
 437                 }
 438                 s.Accounts[newLogin] = s.Accounts[login]
 439                 delete(s.Accounts, login)
 440         }
 441
 442         account := s.Accounts[newLogin]
 443         account.Access = access
 444         account.Name = name
 445         account.Password = password
 446
 447         out, err := yaml.Marshal(&account)
 448         if err != nil {
 449                 return err
 450         }
 451
 452         if err := os.WriteFile(filepath.Join(s.ConfigDir, "Users", newLogin+".yaml"), out, 0666); err != nil {
 453                 return err
 454         }
 455
 456         return nil
 457 }
 458
 459 // DeleteUser deletes the user account
 460 func (s *Server) DeleteUser(login string) error {
 461         s.mux.Lock()
 462         defer s.mux.Unlock()
 463
 464         delete(s.Accounts, login)
 465
 466         return s.FS.Remove(filepath.Join(s.ConfigDir, "Users", login+".yaml"))
 467 }
 468
 469 func (s *Server) connectedUsers() []Field {
 470         s.mux.Lock()
 471         defer s.mux.Unlock()
 472
 473         var connectedUsers []Field
 474         for _, c := range sortedClients(s.Clients) {
 475                 if !c.Agreed {
 476                         continue
 477                 }
 478                 user := User{
 479                         ID:    *c.ID,
 480                         Icon:  c.Icon,
 481                         Flags: c.Flags,
 482                         Name:  string(c.UserName),
 483                 }
 484                 connectedUsers = append(connectedUsers, NewField(fieldUsernameWithInfo, user.Payload()))
 485         }
 486         return connectedUsers
 487 }
 488
 489 func (s *Server) loadBanList(path string) error {
 490         fh, err := os.Open(path)
 491         if err != nil {
 492                 return err
 493         }
 494         decoder := yaml.NewDecoder(fh)
 495
 496         return decoder.Decode(s.banList)
 497 }
 498
 499 // loadThreadedNews loads the threaded news data from disk
 500 func (s *Server) loadThreadedNews(threadedNewsPath string) error {
 501         fh, err := os.Open(threadedNewsPath)
 502         if err != nil {
 503                 return err
 504         }
 505         decoder := yaml.NewDecoder(fh)
 506
 507         return decoder.Decode(s.ThreadedNews)
 508 }
 509
 510 // loadAccounts loads account data from disk
 511 func (s *Server) loadAccounts(userDir string) error {
 512         matches, err := filepath.Glob(filepath.Join(userDir, "*.yaml"))
 513         if err != nil {
 514                 return err
 515         }
 516
 517         if len(matches) == 0 {
 518                 return errors.New("no user accounts found in " + userDir)
 519         }
 520
 521         for _, file := range matches {
 522                 fh, err := s.FS.Open(file)
 523                 if err != nil {
 524                         return err
 525                 }
 526
 527                 account := Account{}
 528                 decoder := yaml.NewDecoder(fh)
 529                 if err := decoder.Decode(&account); err != nil {
 530                         return err
 531                 }
 532
 533                 s.Accounts[account.Login] = &account
 534         }
 535         return nil
 536 }
 537
 538 func (s *Server) loadConfig(path string) error {
 539         fh, err := s.FS.Open(path)
 540         if err != nil {
 541                 return err
 542         }
 543
 544         decoder := yaml.NewDecoder(fh)
 545         err = decoder.Decode(s.Config)
 546         if err != nil {
 547                 return err
 548         }
 549
 550         validate := validator.New()
 551         err = validate.Struct(s.Config)
 552         if err != nil {
 553                 return err
 554         }
 555         return nil
 556 }
 557
 558 // handleNewConnection takes a new net.Conn and performs the initial login sequence
 559 func (s *Server) handleNewConnection(ctx context.Context, rwc io.ReadWriteCloser, remoteAddr string) error {
 560         defer dontPanic(s.Logger)
 561
 562         if err := Handshake(rwc); err != nil {
 563                 return err
 564         }
 565
 566         // Create a new scanner for parsing incoming bytes into transaction tokens
 567         scanner := bufio.NewScanner(rwc)
 568         scanner.Split(transactionScanner)
 569
 570         scanner.Scan()
 571
 572         // Make a new []byte slice and copy the scanner bytes to it.  This is critical to avoid a data race as the
 573         // scanner re-uses the buffer for subsequent scans.
 574         buf := make([]byte, len(scanner.Bytes()))
 575         copy(buf, scanner.Bytes())
 576
 577         var clientLogin Transaction
 578         if _, err := clientLogin.Write(buf); err != nil {
 579                 return err
 580         }
 581
 582         c := s.NewClientConn(rwc, remoteAddr)
 583
 584         // check if remoteAddr is present in the ban list
 585         if banUntil, ok := s.banList[strings.Split(remoteAddr, ":")[0]]; ok {
 586                 // permaban
 587                 if banUntil == nil {
 588                         s.outbox <- *NewTransaction(
 589                                 tranServerMsg,
 590                                 c.ID,
 591                                 NewField(fieldData, []byte("You are permanently banned on this server")),
 592                                 NewField(fieldChatOptions, []byte{0, 0}),
 593                         )
 594                         time.Sleep(1 * time.Second)
 595                         return nil
 596                 } else if time.Now().Before(*banUntil) {
 597                         s.outbox <- *NewTransaction(
 598                                 tranServerMsg,
 599                                 c.ID,
 600                                 NewField(fieldData, []byte("You are temporarily banned on this server")),
 601                                 NewField(fieldChatOptions, []byte{0, 0}),
 602                         )
 603                         time.Sleep(1 * time.Second)
 604                         return nil
 605                 }
 606
 607         }
 608         defer c.Disconnect()
 609
 610         encodedLogin := clientLogin.GetField(fieldUserLogin).Data
 611         encodedPassword := clientLogin.GetField(fieldUserPassword).Data
 612         c.Version = clientLogin.GetField(fieldVersion).Data
 613
 614         var login string
 615         for _, char := range encodedLogin {
 616                 login += string(rune(255 - uint(char)))
 617         }
 618         if login == "" {
 619                 login = GuestAccount
 620         }
 621
 622         c.logger = s.Logger.With("remoteAddr", remoteAddr, "login", login)
 623
 624         // If authentication fails, send error reply and close connection
 625         if !c.Authenticate(login, encodedPassword) {
 626                 t := c.NewErrReply(&clientLogin, "Incorrect login.")
 627                 b, err := t.MarshalBinary()
 628                 if err != nil {
 629                         return err
 630                 }
 631                 if _, err := rwc.Write(b); err != nil {
 632                         return err
 633                 }
 634
 635                 c.logger.Infow("Login failed", "clientVersion", fmt.Sprintf("%x", c.Version))
 636
 637                 return nil
 638         }
 639
 640         if clientLogin.GetField(fieldUserIconID).Data != nil {
 641                 c.Icon = clientLogin.GetField(fieldUserIconID).Data
 642         }
 643
 644         c.Account = c.Server.Accounts[login]
 645
 646         if clientLogin.GetField(fieldUserName).Data != nil {
 647                 if c.Authorize(accessAnyName) {
 648                         c.UserName = clientLogin.GetField(fieldUserName).Data
 649                 } else {
 650                         c.UserName = []byte(c.Account.Name)
 651                 }
 652         }
 653
 654         if c.Authorize(accessDisconUser) {
 655                 c.Flags = []byte{0, 2}
 656         }
 657
 658         s.outbox <- c.NewReply(&clientLogin,
 659                 NewField(fieldVersion, []byte{0x00, 0xbe}),
 660                 NewField(fieldCommunityBannerID, []byte{0, 0}),
 661                 NewField(fieldServerName, []byte(s.Config.Name)),
 662         )
 663
 664         // Send user access privs so client UI knows how to behave
 665         c.Server.outbox <- *NewTransaction(tranUserAccess, c.ID, NewField(fieldUserAccess, c.Account.Access[:]))
 666
 667         // Accounts with accessNoAgreement do not receive the server agreement on login.  The behavior is different between
 668         // client versions.  For 1.2.3 client, we do not send tranShowAgreement.  For other client versions, we send
 669         // tranShowAgreement but with the NoServerAgreement field set to 1.
 670         if c.Authorize(accessNoAgreement) {
 671                 // If client version is nil, then the client uses the 1.2.3 login behavior
 672                 if c.Version != nil {
 673                         c.Server.outbox <- *NewTransaction(tranShowAgreement, c.ID, NewField(fieldNoServerAgreement, []byte{1}))
 674                 }
 675         } else {
 676                 c.Server.outbox <- *NewTransaction(tranShowAgreement, c.ID, NewField(fieldData, s.Agreement))
 677         }
 678
 679         // Used simplified hotline v1.2.3 login flow for clients that do not send login info in tranAgreed
 680         // TODO: figure out a generalized solution that doesn't require playing whack-a-mole for specific client versions
 681         if c.Version == nil || bytes.Equal(c.Version, nostalgiaVersion) || bytes.Equal(c.Version, frogblastVersion) || bytes.Equal(c.Version, obsessionVersion) || bytes.Equal(c.Version, heildrun) {
 682                 c.Agreed = true
 683                 c.logger = c.logger.With("name", string(c.UserName))
 684                 c.logger.Infow("Login successful", "clientVersion", fmt.Sprintf("%v", func() int { i, _ := byteToInt(c.Version); return i }()))
 685
 686                 for _, t := range c.notifyOthers(
 687                         *NewTransaction(
 688                                 tranNotifyChangeUser, nil,
 689                                 NewField(fieldUserName, c.UserName),
 690                                 NewField(fieldUserID, *c.ID),
 691                                 NewField(fieldUserIconID, c.Icon),
 692                                 NewField(fieldUserFlags, c.Flags),
 693                         ),
 694                 ) {
 695                         c.Server.outbox <- t
 696                 }
 697         }
 698
 699         c.Server.Stats.ConnectionCounter += 1
 700         if len(s.Clients) > c.Server.Stats.ConnectionPeak {
 701                 c.Server.Stats.ConnectionPeak = len(s.Clients)
 702         }
 703
 704         // Scan for new transactions and handle them as they come in.
 705         for scanner.Scan() {
 706                 // Make a new []byte slice and copy the scanner bytes to it.  This is critical to avoid a data race as the
 707                 // scanner re-uses the buffer for subsequent scans.
 708                 buf := make([]byte, len(scanner.Bytes()))
 709                 copy(buf, scanner.Bytes())
 710
 711                 var t Transaction
 712                 if _, err := t.Write(buf); err != nil {
 713                         return err
 714                 }
 715
 716                 if err := c.handleTransaction(t); err != nil {
 717                         c.logger.Errorw("Error handling transaction", "err", err)
 718                 }
 719         }
 720         return nil
 721 }
 722
 723 func (s *Server) NewPrivateChat(cc *ClientConn) []byte {
 724         s.PrivateChatsMu.Lock()
 725         defer s.PrivateChatsMu.Unlock()
 726
 727         randID := make([]byte, 4)
 728         rand.Read(randID)
 729         data := binary.BigEndian.Uint32(randID[:])
 730
 731         s.PrivateChats[data] = &PrivateChat{
 732                 ClientConn: make(map[uint16]*ClientConn),
 733         }
 734         s.PrivateChats[data].ClientConn[cc.uint16ID()] = cc
 735
 736         return randID
 737 }
 738
 739 const dlFldrActionSendFile = 1
 740 const dlFldrActionResumeFile = 2
 741 const dlFldrActionNextFile = 3
 742
 743 // handleFileTransfer receives a client net.Conn from the file transfer server, performs the requested transfer type, then closes the connection
 744 func (s *Server) handleFileTransfer(ctx context.Context, rwc io.ReadWriter) error {
 745         defer dontPanic(s.Logger)
 746
 747         txBuf := make([]byte, 16)
 748         if _, err := io.ReadFull(rwc, txBuf); err != nil {
 749                 return err
 750         }
 751
 752         var t transfer
 753         if _, err := t.Write(txBuf); err != nil {
 754                 return err
 755         }
 756
 757         defer func() {
 758                 s.mux.Lock()
 759                 delete(s.fileTransfers, t.ReferenceNumber)
 760                 s.mux.Unlock()
 761
 762                 // Wait a few seconds before closing the connection: this is a workaround for problems
 763                 // observed with Windows clients where the client must initiate close of the TCP connection before
 764                 // the server does.  This is gross and seems unnecessary.  TODO: Revisit?
 765                 time.Sleep(3 * time.Second)
 766         }()
 767
 768         s.mux.Lock()
 769         fileTransfer, ok := s.fileTransfers[t.ReferenceNumber]
 770         s.mux.Unlock()
 771         if !ok {
 772                 return errors.New("invalid transaction ID")
 773         }
 774
 775         defer func() {
 776                 fileTransfer.ClientConn.transfersMU.Lock()
 777                 delete(fileTransfer.ClientConn.transfers[fileTransfer.Type], t.ReferenceNumber)
 778                 fileTransfer.ClientConn.transfersMU.Unlock()
 779         }()
 780
 781         rLogger := s.Logger.With(
 782                 "remoteAddr", ctx.Value(contextKeyReq).(requestCtx).remoteAddr,
 783                 "login", fileTransfer.ClientConn.Account.Login,
 784                 "name", string(fileTransfer.ClientConn.UserName),
 785         )
 786
 787         fullPath, err := readPath(s.Config.FileRoot, fileTransfer.FilePath, fileTransfer.FileName)
 788         if err != nil {
 789                 return err
 790         }
 791
 792         switch fileTransfer.Type {
 793         case bannerDownload:
 794                 if err := s.bannerDownload(rwc); err != nil {
 795                         return err
 796                 }
 797         case FileDownload:
 798                 s.Stats.DownloadCounter += 1
 799                 s.Stats.DownloadsInProgress += 1
 800                 defer func() {
 801                         s.Stats.DownloadsInProgress -= 1
 802                 }()
 803
 804                 var dataOffset int64
 805                 if fileTransfer.fileResumeData != nil {
 806                         dataOffset = int64(binary.BigEndian.Uint32(fileTransfer.fileResumeData.ForkInfoList[0].DataSize[:]))
 807                 }
 808
 809                 fw, err := newFileWrapper(s.FS, fullPath, 0)
 810                 if err != nil {
 811                         return err
 812                 }
 813
 814                 rLogger.Infow("File download started", "filePath", fullPath)
 815
 816                 // if file transfer options are included, that means this is a "quick preview" request from a 1.5+ client
 817                 if fileTransfer.options == nil {
 818                         // Start by sending flat file object to client
 819                         if _, err := rwc.Write(fw.ffo.BinaryMarshal()); err != nil {
 820                                 return err
 821                         }
 822                 }
 823
 824                 file, err := fw.dataForkReader()
 825                 if err != nil {
 826                         return err
 827                 }
 828
 829                 br := bufio.NewReader(file)
 830                 if _, err := br.Discard(int(dataOffset)); err != nil {
 831                         return err
 832                 }
 833
 834                 if _, err = io.Copy(rwc, io.TeeReader(br, fileTransfer.bytesSentCounter)); err != nil {
 835                         return err
 836                 }
 837
 838                 // if the client requested to resume transfer, do not send the resource fork header, or it will be appended into the fileWrapper data
 839                 if fileTransfer.fileResumeData == nil {
 840                         err = binary.Write(rwc, binary.BigEndian, fw.rsrcForkHeader())
 841                         if err != nil {
 842                                 return err
 843                         }
 844                 }
 845
 846                 rFile, err := fw.rsrcForkFile()
 847                 if err != nil {
 848                         return nil
 849                 }
 850
 851                 if _, err = io.Copy(rwc, io.TeeReader(rFile, fileTransfer.bytesSentCounter)); err != nil {
 852                         return err
 853                 }
 854
 855         case FileUpload:
 856                 s.Stats.UploadCounter += 1
 857                 s.Stats.UploadsInProgress += 1
 858                 defer func() { s.Stats.UploadsInProgress -= 1 }()
 859
 860                 var file *os.File
 861
 862                 // A file upload has three possible cases:
 863                 // 1) Upload a new file
 864                 // 2) Resume a partially transferred file
 865                 // 3) Replace a fully uploaded file
 866                 //  We have to infer which case applies by inspecting what is already on the filesystem
 867
 868                 // 1) Check for existing file:
 869                 _, err = os.Stat(fullPath)
 870                 if err == nil {
 871                         return errors.New("existing file found at " + fullPath)
 872                 }
 873                 if errors.Is(err, fs.ErrNotExist) {
 874                         // If not found, open or create a new .incomplete file
 875                         file, err = os.OpenFile(fullPath+incompleteFileSuffix, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0644)
 876                         if err != nil {
 877                                 return err
 878                         }
 879                 }
 880
 881                 f, err := newFileWrapper(s.FS, fullPath, 0)
 882                 if err != nil {
 883                         return err
 884                 }
 885
 886                 rLogger.Infow("File upload started", "dstFile", fullPath)
 887
 888                 rForkWriter := io.Discard
 889                 iForkWriter := io.Discard
 890                 if s.Config.PreserveResourceForks {
 891                         rForkWriter, err = f.rsrcForkWriter()
 892                         if err != nil {
 893                                 return err
 894                         }
 895
 896                         iForkWriter, err = f.infoForkWriter()
 897                         if err != nil {
 898                                 return err
 899                         }
 900                 }
 901
 902                 if err := receiveFile(rwc, file, rForkWriter, iForkWriter, fileTransfer.bytesSentCounter); err != nil {
 903                         s.Logger.Error(err)
 904                 }
 905
 906                 if err := file.Close(); err != nil {
 907                         return err
 908                 }
 909
 910                 if err := s.FS.Rename(fullPath+".incomplete", fullPath); err != nil {
 911                         return err
 912                 }
 913
 914                 rLogger.Infow("File upload complete", "dstFile", fullPath)
 915
 916         case FolderDownload:
 917                 s.Stats.DownloadCounter += 1
 918                 s.Stats.DownloadsInProgress += 1
 919                 defer func() { s.Stats.DownloadsInProgress -= 1 }()
 920
 921                 // Folder Download flow:
 922                 // 1. Get filePath from the transfer
 923                 // 2. Iterate over files
 924                 // 3. For each fileWrapper:
 925                 //       Send fileWrapper header to client
 926                 // The client can reply in 3 ways:
 927                 //
 928                 // 1. If type is an odd number (unknown type?), or fileWrapper download for the current fileWrapper is completed:
 929                 //              client sends []byte{0x00, 0x03} to tell the server to continue to the next fileWrapper
 930                 //
 931                 // 2. If download of a fileWrapper is to be resumed:
 932                 //              client sends:
 933                 //                      []byte{0x00, 0x02} // download folder action
 934                 //                      [2]byte // Resume data size
 935                 //                      []byte fileWrapper resume data (see myField_FileResumeData)
 936                 //
 937                 // 3. Otherwise, download of the fileWrapper is requested and client sends []byte{0x00, 0x01}
 938                 //
 939                 // When download is requested (case 2 or 3), server replies with:
 940                 //                      [4]byte - fileWrapper size
 941                 //                      []byte  - Flattened File Object
 942                 //
 943                 // After every fileWrapper download, client could request next fileWrapper with:
 944                 //                      []byte{0x00, 0x03}
 945                 //
 946                 // This notifies the server to send the next item header
 947
 948                 basePathLen := len(fullPath)
 949
 950                 rLogger.Infow("Start folder download", "path", fullPath)
 951
 952                 nextAction := make([]byte, 2)
 953                 if _, err := io.ReadFull(rwc, nextAction); err != nil {
 954                         return err
 955                 }
 956
 957                 i := 0
 958                 err = filepath.Walk(fullPath+"/", func(path string, info os.FileInfo, err error) error {
 959                         s.Stats.DownloadCounter += 1
 960                         i += 1
 961
 962                         if err != nil {
 963                                 return err
 964                         }
 965
 966                         // skip dot files
 967                         if strings.HasPrefix(info.Name(), ".") {
 968                                 return nil
 969                         }
 970
 971                         hlFile, err := newFileWrapper(s.FS, path, 0)
 972                         if err != nil {
 973                                 return err
 974                         }
 975
 976                         subPath := path[basePathLen+1:]
 977                         rLogger.Debugw("Sending fileheader", "i", i, "path", path, "fullFilePath", fullPath, "subPath", subPath, "IsDir", info.IsDir())
 978
 979                         if i == 1 {
 980                                 return nil
 981                         }
 982
 983                         fileHeader := NewFileHeader(subPath, info.IsDir())
 984
 985                         // Send the fileWrapper header to client
 986                         if _, err := rwc.Write(fileHeader.Payload()); err != nil {
 987                                 s.Logger.Errorf("error sending file header: %v", err)
 988                                 return err
 989                         }
 990
 991                         // Read the client's Next Action request
 992                         if _, err := io.ReadFull(rwc, nextAction); err != nil {
 993                                 return err
 994                         }
 995
 996                         rLogger.Debugw("Client folder download action", "action", fmt.Sprintf("%X", nextAction[0:2]))
 997
 998                         var dataOffset int64
 999
1000                         switch nextAction[1] {
1001                         case dlFldrActionResumeFile:
1002                                 // get size of resumeData
1003                                 resumeDataByteLen := make([]byte, 2)
1004                                 if _, err := io.ReadFull(rwc, resumeDataByteLen); err != nil {
1005                                         return err
1006                                 }
1007
1008                                 resumeDataLen := binary.BigEndian.Uint16(resumeDataByteLen)
1009                                 resumeDataBytes := make([]byte, resumeDataLen)
1010                                 if _, err := io.ReadFull(rwc, resumeDataBytes); err != nil {
1011                                         return err
1012                                 }
1013
1014                                 var frd FileResumeData
1015                                 if err := frd.UnmarshalBinary(resumeDataBytes); err != nil {
1016                                         return err
1017                                 }
1018                                 dataOffset = int64(binary.BigEndian.Uint32(frd.ForkInfoList[0].DataSize[:]))
1019                         case dlFldrActionNextFile:
1020                                 // client asked to skip this file
1021                                 return nil
1022                         }
1023
1024                         if info.IsDir() {
1025                                 return nil
1026                         }
1027
1028                         rLogger.Infow("File download started",
1029                                 "fileName", info.Name(),
1030                                 "TransferSize", fmt.Sprintf("%x", hlFile.ffo.TransferSize(dataOffset)),
1031                         )
1032
1033                         // Send file size to client
1034                         if _, err := rwc.Write(hlFile.ffo.TransferSize(dataOffset)); err != nil {
1035                                 s.Logger.Error(err)
1036                                 return err
1037                         }
1038
1039                         // Send ffo bytes to client
1040                         if _, err := rwc.Write(hlFile.ffo.BinaryMarshal()); err != nil {
1041                                 s.Logger.Error(err)
1042                                 return err
1043                         }
1044
1045                         file, err := s.FS.Open(path)
1046                         if err != nil {
1047                                 return err
1048                         }
1049
1050                         // wr := bufio.NewWriterSize(rwc, 1460)
1051                         if _, err = io.Copy(rwc, io.TeeReader(file, fileTransfer.bytesSentCounter)); err != nil {
1052                                 return err
1053                         }
1054
1055                         if nextAction[1] != 2 && hlFile.ffo.FlatFileHeader.ForkCount[1] == 3 {
1056                                 err = binary.Write(rwc, binary.BigEndian, hlFile.rsrcForkHeader())
1057                                 if err != nil {
1058                                         return err
1059                                 }
1060
1061                                 rFile, err := hlFile.rsrcForkFile()
1062                                 if err != nil {
1063                                         return err
1064                                 }
1065
1066                                 if _, err = io.Copy(rwc, io.TeeReader(rFile, fileTransfer.bytesSentCounter)); err != nil {
1067                                         return err
1068                                 }
1069                         }
1070
1071                         // Read the client's Next Action request.  This is always 3, I think?
1072                         if _, err := io.ReadFull(rwc, nextAction); err != nil {
1073                                 return err
1074                         }
1075
1076                         return nil
1077                 })
1078
1079                 if err != nil {
1080                         return err
1081                 }
1082
1083         case FolderUpload:
1084                 s.Stats.UploadCounter += 1
1085                 s.Stats.UploadsInProgress += 1
1086                 defer func() { s.Stats.UploadsInProgress -= 1 }()
1087                 rLogger.Infow(
1088                         "Folder upload started",
1089                         "dstPath", fullPath,
1090                         "TransferSize", binary.BigEndian.Uint32(fileTransfer.TransferSize),
1091                         "FolderItemCount", fileTransfer.FolderItemCount,
1092                 )
1093
1094                 // Check if the target folder exists.  If not, create it.
1095                 if _, err := s.FS.Stat(fullPath); os.IsNotExist(err) {
1096                         if err := s.FS.Mkdir(fullPath, 0777); err != nil {
1097                                 return err
1098                         }
1099                 }
1100
1101                 // Begin the folder upload flow by sending the "next file action" to client
1102                 if _, err := rwc.Write([]byte{0, dlFldrActionNextFile}); err != nil {
1103                         return err
1104                 }
1105
1106                 fileSize := make([]byte, 4)
1107
1108                 for i := 0; i < fileTransfer.ItemCount(); i++ {
1109                         s.Stats.UploadCounter += 1
1110
1111                         var fu folderUpload
1112                         if _, err := io.ReadFull(rwc, fu.DataSize[:]); err != nil {
1113                                 return err
1114                         }
1115                         if _, err := io.ReadFull(rwc, fu.IsFolder[:]); err != nil {
1116                                 return err
1117                         }
1118                         if _, err := io.ReadFull(rwc, fu.PathItemCount[:]); err != nil {
1119                                 return err
1120                         }
1121
1122                         fu.FileNamePath = make([]byte, binary.BigEndian.Uint16(fu.DataSize[:])-4) // -4 to subtract the path separator bytes
1123
1124                         if _, err := io.ReadFull(rwc, fu.FileNamePath); err != nil {
1125                                 return err
1126                         }
1127
1128                         rLogger.Infow(
1129                                 "Folder upload continued",
1130                                 "FormattedPath", fu.FormattedPath(),
1131                                 "IsFolder", fmt.Sprintf("%x", fu.IsFolder),
1132                                 "PathItemCount", binary.BigEndian.Uint16(fu.PathItemCount[:]),
1133                         )
1134
1135                         if fu.IsFolder == [2]byte{0, 1} {
1136                                 if _, err := os.Stat(filepath.Join(fullPath, fu.FormattedPath())); os.IsNotExist(err) {
1137                                         if err := os.Mkdir(filepath.Join(fullPath, fu.FormattedPath()), 0777); err != nil {
1138                                                 return err
1139                                         }
1140                                 }
1141
1142                                 // Tell client to send next file
1143                                 if _, err := rwc.Write([]byte{0, dlFldrActionNextFile}); err != nil {
1144                                         return err
1145                                 }
1146                         } else {
1147                                 nextAction := dlFldrActionSendFile
1148
1149                                 // Check if we have the full file already.  If so, send dlFldrAction_NextFile to client to skip.
1150                                 _, err = os.Stat(filepath.Join(fullPath, fu.FormattedPath()))
1151                                 if err != nil && !errors.Is(err, fs.ErrNotExist) {
1152                                         return err
1153                                 }
1154                                 if err == nil {
1155                                         nextAction = dlFldrActionNextFile
1156                                 }
1157
1158                                 //  Check if we have a partial file already.  If so, send dlFldrAction_ResumeFile to client to resume upload.
1159                                 incompleteFile, err := os.Stat(filepath.Join(fullPath, fu.FormattedPath()+incompleteFileSuffix))
1160                                 if err != nil && !errors.Is(err, fs.ErrNotExist) {
1161                                         return err
1162                                 }
1163                                 if err == nil {
1164                                         nextAction = dlFldrActionResumeFile
1165                                 }
1166
1167                                 if _, err := rwc.Write([]byte{0, uint8(nextAction)}); err != nil {
1168                                         return err
1169                                 }
1170
1171                                 switch nextAction {
1172                                 case dlFldrActionNextFile:
1173                                         continue
1174                                 case dlFldrActionResumeFile:
1175                                         offset := make([]byte, 4)
1176                                         binary.BigEndian.PutUint32(offset, uint32(incompleteFile.Size()))
1177
1178                                         file, err := os.OpenFile(fullPath+"/"+fu.FormattedPath()+incompleteFileSuffix, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
1179                                         if err != nil {
1180                                                 return err
1181                                         }
1182
1183                                         fileResumeData := NewFileResumeData([]ForkInfoList{*NewForkInfoList(offset)})
1184
1185                                         b, _ := fileResumeData.BinaryMarshal()
1186
1187                                         bs := make([]byte, 2)
1188                                         binary.BigEndian.PutUint16(bs, uint16(len(b)))
1189
1190                                         if _, err := rwc.Write(append(bs, b...)); err != nil {
1191                                                 return err
1192                                         }
1193
1194                                         if _, err := io.ReadFull(rwc, fileSize); err != nil {
1195                                                 return err
1196                                         }
1197
1198                                         if err := receiveFile(rwc, file, ioutil.Discard, ioutil.Discard, fileTransfer.bytesSentCounter); err != nil {
1199                                                 s.Logger.Error(err)
1200                                         }
1201
1202                                         err = os.Rename(fullPath+"/"+fu.FormattedPath()+".incomplete", fullPath+"/"+fu.FormattedPath())
1203                                         if err != nil {
1204                                                 return err
1205                                         }
1206
1207                                 case dlFldrActionSendFile:
1208                                         if _, err := io.ReadFull(rwc, fileSize); err != nil {
1209                                                 return err
1210                                         }
1211
1212                                         filePath := filepath.Join(fullPath, fu.FormattedPath())
1213
1214                                         hlFile, err := newFileWrapper(s.FS, filePath, 0)
1215                                         if err != nil {
1216                                                 return err
1217                                         }
1218
1219                                         rLogger.Infow("Starting file transfer", "path", filePath, "fileNum", i+1, "fileSize", binary.BigEndian.Uint32(fileSize))
1220
1221                                         incWriter, err := hlFile.incFileWriter()
1222                                         if err != nil {
1223                                                 return err
1224                                         }
1225
1226                                         rForkWriter := io.Discard
1227                                         iForkWriter := io.Discard
1228                                         if s.Config.PreserveResourceForks {
1229                                                 iForkWriter, err = hlFile.infoForkWriter()
1230                                                 if err != nil {
1231                                                         return err
1232                                                 }
1233
1234                                                 rForkWriter, err = hlFile.rsrcForkWriter()
1235                                                 if err != nil {
1236                                                         return err
1237                                                 }
1238                                         }
1239                                         if err := receiveFile(rwc, incWriter, rForkWriter, iForkWriter, fileTransfer.bytesSentCounter); err != nil {
1240                                                 return err
1241                                         }
1242
1243                                         if err := os.Rename(filePath+".incomplete", filePath); err != nil {
1244                                                 return err
1245                                         }
1246                                 }
1247
1248                                 // Tell client to send next fileWrapper
1249                                 if _, err := rwc.Write([]byte{0, dlFldrActionNextFile}); err != nil {
1250                                         return err
1251                                 }
1252                         }
1253                 }
1254                 rLogger.Infof("Folder upload complete")
1255         }
1256
1257         return nil
1258 }