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[rbdr/mobius] / hotline / server.go
1 package hotline
2
3 import (
4 "bufio"
5 "context"
6 "encoding/binary"
7 "errors"
8 "fmt"
9 "github.com/go-playground/validator/v10"
10 "go.uber.org/zap"
11 "golang.org/x/text/encoding/charmap"
12 "gopkg.in/yaml.v3"
13 "io"
14 "io/fs"
15 "math/big"
16 "math/rand"
17 "net"
18 "os"
19 "path"
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 }
33
34 // Converts bytes from Mac Roman encoding to UTF-8
35 var txtDecoder = charmap.Macintosh.NewDecoder()
36
37 // Converts bytes from UTF-8 to Mac Roman encoding
38 var txtEncoder = charmap.Macintosh.NewEncoder()
39
40 type Server struct {
41 NetInterface string
42 Port int
43 Accounts map[string]*Account
44 Agreement []byte
45 Clients map[uint16]*ClientConn
46 fileTransfers map[[4]byte]*FileTransfer
47
48 Config *Config
49 ConfigDir string
50 Logger *zap.SugaredLogger
51
52 PrivateChatsMu sync.Mutex
53 PrivateChats map[uint32]*PrivateChat
54
55 NextGuestID *uint16
56 TrackerPassID [4]byte
57
58 StatsMu sync.Mutex
59 Stats *Stats
60
61 FS FileStore // Storage backend to use for File storage
62
63 outbox chan Transaction
64 mux sync.Mutex
65
66 threadedNewsMux sync.Mutex
67 ThreadedNews *ThreadedNews
68
69 flatNewsMux sync.Mutex
70 FlatNews []byte
71
72 banListMU sync.Mutex
73 banList map[string]*time.Time
74 }
75
76 func (s *Server) CurrentStats() Stats {
77 s.StatsMu.Lock()
78 defer s.StatsMu.Unlock()
79
80 stats := s.Stats
81 stats.CurrentlyConnected = len(s.Clients)
82
83 return *stats
84 }
85
86 type PrivateChat struct {
87 Subject string
88 ClientConn map[uint16]*ClientConn
89 }
90
91 func (s *Server) ListenAndServe(ctx context.Context, cancelRoot context.CancelFunc) error {
92 s.Logger.Infow("Hotline server started",
93 "version", VERSION,
94 "API port", fmt.Sprintf("%s:%v", s.NetInterface, s.Port),
95 "Transfer port", fmt.Sprintf("%s:%v", s.NetInterface, s.Port+1),
96 )
97
98 var wg sync.WaitGroup
99
100 wg.Add(1)
101 go func() {
102 ln, err := net.Listen("tcp", fmt.Sprintf("%s:%v", s.NetInterface, s.Port))
103 if err != nil {
104 s.Logger.Fatal(err)
105 }
106
107 s.Logger.Fatal(s.Serve(ctx, ln))
108 }()
109
110 wg.Add(1)
111 go func() {
112 ln, err := net.Listen("tcp", fmt.Sprintf("%s:%v", s.NetInterface, s.Port+1))
113 if err != nil {
114 s.Logger.Fatal(err)
115 }
116
117 s.Logger.Fatal(s.ServeFileTransfers(ctx, ln))
118 }()
119
120 wg.Wait()
121
122 return nil
123 }
124
125 func (s *Server) ServeFileTransfers(ctx context.Context, ln net.Listener) error {
126 for {
127 conn, err := ln.Accept()
128 if err != nil {
129 return err
130 }
131
132 go func() {
133 defer func() { _ = conn.Close() }()
134
135 err = s.handleFileTransfer(
136 context.WithValue(ctx, contextKeyReq, requestCtx{
137 remoteAddr: conn.RemoteAddr().String(),
138 }),
139 conn,
140 )
141
142 if err != nil {
143 s.Logger.Errorw("file transfer error", "reason", err)
144 }
145 }()
146 }
147 }
148
149 func (s *Server) sendTransaction(t Transaction) error {
150 clientID, err := byteToInt(*t.clientID)
151 if err != nil {
152 return err
153 }
154
155 s.mux.Lock()
156 client := s.Clients[uint16(clientID)]
157 s.mux.Unlock()
158 if client == nil {
159 return fmt.Errorf("invalid client id %v", *t.clientID)
160 }
161
162 b, err := t.MarshalBinary()
163 if err != nil {
164 return err
165 }
166
167 _, err = client.Connection.Write(b)
168 if err != nil {
169 return err
170 }
171
172 return nil
173 }
174
175 func (s *Server) processOutbox() {
176 for {
177 t := <-s.outbox
178 go func() {
179 if err := s.sendTransaction(t); err != nil {
180 s.Logger.Errorw("error sending transaction", "err", err)
181 }
182 }()
183 }
184 }
185
186 func (s *Server) Serve(ctx context.Context, ln net.Listener) error {
187 go s.processOutbox()
188
189 for {
190 conn, err := ln.Accept()
191 if err != nil {
192 s.Logger.Errorw("error accepting connection", "err", err)
193 }
194 connCtx := context.WithValue(ctx, contextKeyReq, requestCtx{
195 remoteAddr: conn.RemoteAddr().String(),
196 })
197
198 go func() {
199 s.Logger.Infow("Connection established", "RemoteAddr", conn.RemoteAddr())
200
201 defer conn.Close()
202 if err := s.handleNewConnection(connCtx, conn, conn.RemoteAddr().String()); err != nil {
203 if err == io.EOF {
204 s.Logger.Infow("Client disconnected", "RemoteAddr", conn.RemoteAddr())
205 } else {
206 s.Logger.Errorw("error serving request", "RemoteAddr", conn.RemoteAddr(), "err", err)
207 }
208 }
209 }()
210 }
211 }
212
213 const (
214 agreementFile = "Agreement.txt"
215 )
216
217 // NewServer constructs a new Server from a config dir
218 func NewServer(configDir, netInterface string, netPort int, logger *zap.SugaredLogger, fs FileStore) (*Server, error) {
219 server := Server{
220 NetInterface: netInterface,
221 Port: netPort,
222 Accounts: make(map[string]*Account),
223 Config: new(Config),
224 Clients: make(map[uint16]*ClientConn),
225 fileTransfers: make(map[[4]byte]*FileTransfer),
226 PrivateChats: make(map[uint32]*PrivateChat),
227 ConfigDir: configDir,
228 Logger: logger,
229 NextGuestID: new(uint16),
230 outbox: make(chan Transaction),
231 Stats: &Stats{Since: time.Now()},
232 ThreadedNews: &ThreadedNews{},
233 FS: fs,
234 banList: make(map[string]*time.Time),
235 }
236
237 var err error
238
239 // generate a new random passID for tracker registration
240 if _, err := rand.Read(server.TrackerPassID[:]); err != nil {
241 return nil, err
242 }
243
244 server.Agreement, err = os.ReadFile(filepath.Join(configDir, agreementFile))
245 if err != nil {
246 return nil, err
247 }
248
249 if server.FlatNews, err = os.ReadFile(filepath.Join(configDir, "MessageBoard.txt")); err != nil {
250 return nil, err
251 }
252
253 // try to load the ban list, but ignore errors as this file may not be present or may be empty
254 _ = server.loadBanList(filepath.Join(configDir, "Banlist.yaml"))
255
256 if err := server.loadThreadedNews(filepath.Join(configDir, "ThreadedNews.yaml")); err != nil {
257 return nil, err
258 }
259
260 if err := server.loadConfig(filepath.Join(configDir, "config.yaml")); err != nil {
261 return nil, err
262 }
263
264 if err := server.loadAccounts(filepath.Join(configDir, "Users/")); err != nil {
265 return nil, err
266 }
267
268 // If the FileRoot is an absolute path, use it, otherwise treat as a relative path to the config dir.
269 if !filepath.IsAbs(server.Config.FileRoot) {
270 server.Config.FileRoot = filepath.Join(configDir, server.Config.FileRoot)
271 }
272
273 *server.NextGuestID = 1
274
275 if server.Config.EnableTrackerRegistration {
276 server.Logger.Infow(
277 "Tracker registration enabled",
278 "frequency", fmt.Sprintf("%vs", trackerUpdateFrequency),
279 "trackers", server.Config.Trackers,
280 )
281
282 go func() {
283 for {
284 tr := &TrackerRegistration{
285 UserCount: server.userCount(),
286 PassID: server.TrackerPassID,
287 Name: server.Config.Name,
288 Description: server.Config.Description,
289 }
290 binary.BigEndian.PutUint16(tr.Port[:], uint16(server.Port))
291 for _, t := range server.Config.Trackers {
292 if err := register(t, tr); err != nil {
293 server.Logger.Errorw("unable to register with tracker %v", "error", err)
294 }
295 server.Logger.Debugw("Sent Tracker registration", "addr", t)
296 }
297
298 time.Sleep(trackerUpdateFrequency * time.Second)
299 }
300 }()
301 }
302
303 // Start Client Keepalive go routine
304 go server.keepaliveHandler()
305
306 return &server, nil
307 }
308
309 func (s *Server) userCount() int {
310 s.mux.Lock()
311 defer s.mux.Unlock()
312
313 return len(s.Clients)
314 }
315
316 func (s *Server) keepaliveHandler() {
317 for {
318 time.Sleep(idleCheckInterval * time.Second)
319 s.mux.Lock()
320
321 for _, c := range s.Clients {
322 c.IdleTime += idleCheckInterval
323 if c.IdleTime > userIdleSeconds && !c.Idle {
324 c.Idle = true
325
326 flagBitmap := big.NewInt(int64(binary.BigEndian.Uint16(c.Flags)))
327 flagBitmap.SetBit(flagBitmap, UserFlagAway, 1)
328 binary.BigEndian.PutUint16(c.Flags, uint16(flagBitmap.Int64()))
329
330 c.sendAll(
331 TranNotifyChangeUser,
332 NewField(FieldUserID, *c.ID),
333 NewField(FieldUserFlags, c.Flags),
334 NewField(FieldUserName, c.UserName),
335 NewField(FieldUserIconID, c.Icon),
336 )
337 }
338 }
339 s.mux.Unlock()
340 }
341 }
342
343 func (s *Server) writeBanList() error {
344 s.banListMU.Lock()
345 defer s.banListMU.Unlock()
346
347 out, err := yaml.Marshal(s.banList)
348 if err != nil {
349 return err
350 }
351 err = os.WriteFile(
352 filepath.Join(s.ConfigDir, "Banlist.yaml"),
353 out,
354 0666,
355 )
356 return err
357 }
358
359 func (s *Server) writeThreadedNews() error {
360 s.threadedNewsMux.Lock()
361 defer s.threadedNewsMux.Unlock()
362
363 out, err := yaml.Marshal(s.ThreadedNews)
364 if err != nil {
365 return err
366 }
367 err = s.FS.WriteFile(
368 filepath.Join(s.ConfigDir, "ThreadedNews.yaml"),
369 out,
370 0666,
371 )
372 return err
373 }
374
375 func (s *Server) NewClientConn(conn io.ReadWriteCloser, remoteAddr string) *ClientConn {
376 s.mux.Lock()
377 defer s.mux.Unlock()
378
379 clientConn := &ClientConn{
380 ID: &[]byte{0, 0},
381 Icon: []byte{0, 0},
382 Flags: []byte{0, 0},
383 UserName: []byte{},
384 Connection: conn,
385 Server: s,
386 Version: []byte{},
387 AutoReply: []byte{},
388 RemoteAddr: remoteAddr,
389 transfers: map[int]map[[4]byte]*FileTransfer{
390 FileDownload: {},
391 FileUpload: {},
392 FolderDownload: {},
393 FolderUpload: {},
394 bannerDownload: {},
395 },
396 }
397
398 *s.NextGuestID++
399 ID := *s.NextGuestID
400
401 binary.BigEndian.PutUint16(*clientConn.ID, ID)
402 s.Clients[ID] = clientConn
403
404 return clientConn
405 }
406
407 // NewUser creates a new user account entry in the server map and config file
408 func (s *Server) NewUser(login, name, password string, access accessBitmap) error {
409 s.mux.Lock()
410 defer s.mux.Unlock()
411
412 account := Account{
413 Login: login,
414 Name: name,
415 Password: hashAndSalt([]byte(password)),
416 Access: access,
417 }
418 out, err := yaml.Marshal(&account)
419 if err != nil {
420 return err
421 }
422
423 // Create account file, returning an error if one already exists.
424 file, err := os.OpenFile(
425 filepath.Join(s.ConfigDir, "Users", path.Join("/", login)+".yaml"),
426 os.O_CREATE|os.O_EXCL|os.O_WRONLY,
427 0644,
428 )
429 if err != nil {
430 return err
431 }
432 defer file.Close()
433
434 _, err = file.Write(out)
435 if err != nil {
436 return fmt.Errorf("error writing account file: %w", err)
437 }
438
439 s.Accounts[login] = &account
440
441 return nil
442 }
443
444 func (s *Server) UpdateUser(login, newLogin, name, password string, access accessBitmap) error {
445 s.mux.Lock()
446 defer s.mux.Unlock()
447
448 // update renames the user login
449 if login != newLogin {
450 err := os.Rename(filepath.Join(s.ConfigDir, "Users", path.Join("/", login)+".yaml"), filepath.Join(s.ConfigDir, "Users", path.Join("/", newLogin)+".yaml"))
451 if err != nil {
452 return fmt.Errorf("unable to rename account: %w", err)
453 }
454 s.Accounts[newLogin] = s.Accounts[login]
455 s.Accounts[newLogin].Login = newLogin
456 delete(s.Accounts, login)
457 }
458
459 account := s.Accounts[newLogin]
460 account.Access = access
461 account.Name = name
462 account.Password = password
463
464 out, err := yaml.Marshal(&account)
465 if err != nil {
466 return err
467 }
468
469 if err := os.WriteFile(filepath.Join(s.ConfigDir, "Users", newLogin+".yaml"), out, 0666); err != nil {
470 return err
471 }
472
473 return nil
474 }
475
476 // DeleteUser deletes the user account
477 func (s *Server) DeleteUser(login string) error {
478 s.mux.Lock()
479 defer s.mux.Unlock()
480
481 err := s.FS.Remove(filepath.Join(s.ConfigDir, "Users", path.Join("/", login)+".yaml"))
482 if err != nil {
483 return err
484 }
485
486 delete(s.Accounts, login)
487
488 return nil
489 }
490
491 func (s *Server) connectedUsers() []Field {
492 s.mux.Lock()
493 defer s.mux.Unlock()
494
495 var connectedUsers []Field
496 for _, c := range sortedClients(s.Clients) {
497 b, err := io.ReadAll(&User{
498 ID: *c.ID,
499 Icon: c.Icon,
500 Flags: c.Flags,
501 Name: string(c.UserName),
502 })
503 if err != nil {
504 return nil
505 }
506 connectedUsers = append(connectedUsers, NewField(FieldUsernameWithInfo, b))
507 }
508 return connectedUsers
509 }
510
511 func (s *Server) loadBanList(path string) error {
512 fh, err := os.Open(path)
513 if err != nil {
514 return err
515 }
516 decoder := yaml.NewDecoder(fh)
517
518 return decoder.Decode(s.banList)
519 }
520
521 // loadThreadedNews loads the threaded news data from disk
522 func (s *Server) loadThreadedNews(threadedNewsPath string) error {
523 fh, err := os.Open(threadedNewsPath)
524 if err != nil {
525 return err
526 }
527 decoder := yaml.NewDecoder(fh)
528
529 return decoder.Decode(s.ThreadedNews)
530 }
531
532 // loadAccounts loads account data from disk
533 func (s *Server) loadAccounts(userDir string) error {
534 matches, err := filepath.Glob(filepath.Join(userDir, "*.yaml"))
535 if err != nil {
536 return err
537 }
538
539 if len(matches) == 0 {
540 return errors.New("no user accounts found in " + userDir)
541 }
542
543 for _, file := range matches {
544 fh, err := s.FS.Open(file)
545 if err != nil {
546 return err
547 }
548
549 account := Account{}
550 decoder := yaml.NewDecoder(fh)
551 if err = decoder.Decode(&account); err != nil {
552 return fmt.Errorf("error loading account %s: %w", file, err)
553 }
554
555 s.Accounts[account.Login] = &account
556 }
557 return nil
558 }
559
560 func (s *Server) loadConfig(path string) error {
561 fh, err := s.FS.Open(path)
562 if err != nil {
563 return err
564 }
565
566 decoder := yaml.NewDecoder(fh)
567 err = decoder.Decode(s.Config)
568 if err != nil {
569 return err
570 }
571
572 validate := validator.New()
573 err = validate.Struct(s.Config)
574 if err != nil {
575 return err
576 }
577 return nil
578 }
579
580 // handleNewConnection takes a new net.Conn and performs the initial login sequence
581 func (s *Server) handleNewConnection(ctx context.Context, rwc io.ReadWriteCloser, remoteAddr string) error {
582 defer dontPanic(s.Logger)
583
584 if err := Handshake(rwc); err != nil {
585 return err
586 }
587
588 // Create a new scanner for parsing incoming bytes into transaction tokens
589 scanner := bufio.NewScanner(rwc)
590 scanner.Split(transactionScanner)
591
592 scanner.Scan()
593
594 // Make a new []byte slice and copy the scanner bytes to it. This is critical to avoid a data race as the
595 // scanner re-uses the buffer for subsequent scans.
596 buf := make([]byte, len(scanner.Bytes()))
597 copy(buf, scanner.Bytes())
598
599 var clientLogin Transaction
600 if _, err := clientLogin.Write(buf); err != nil {
601 return err
602 }
603
604 // check if remoteAddr is present in the ban list
605 if banUntil, ok := s.banList[strings.Split(remoteAddr, ":")[0]]; ok {
606 // permaban
607 if banUntil == nil {
608 t := NewTransaction(
609 TranServerMsg,
610 &[]byte{0, 0},
611 NewField(FieldData, []byte("You are permanently banned on this server")),
612 NewField(FieldChatOptions, []byte{0, 0}),
613 )
614
615 b, err := t.MarshalBinary()
616 if err != nil {
617 return err
618 }
619
620 _, err = rwc.Write(b)
621 if err != nil {
622 return err
623 }
624
625 time.Sleep(1 * time.Second)
626 return nil
627 }
628
629 // temporary ban
630 if time.Now().Before(*banUntil) {
631 t := NewTransaction(
632 TranServerMsg,
633 &[]byte{0, 0},
634 NewField(FieldData, []byte("You are temporarily banned on this server")),
635 NewField(FieldChatOptions, []byte{0, 0}),
636 )
637 b, err := t.MarshalBinary()
638 if err != nil {
639 return err
640 }
641
642 _, err = rwc.Write(b)
643 if err != nil {
644 return err
645 }
646
647 time.Sleep(1 * time.Second)
648 return nil
649 }
650 }
651
652 c := s.NewClientConn(rwc, remoteAddr)
653 defer c.Disconnect()
654
655 encodedLogin := clientLogin.GetField(FieldUserLogin).Data
656 encodedPassword := clientLogin.GetField(FieldUserPassword).Data
657 c.Version = clientLogin.GetField(FieldVersion).Data
658
659 var login string
660 for _, char := range encodedLogin {
661 login += string(rune(255 - uint(char)))
662 }
663 if login == "" {
664 login = GuestAccount
665 }
666
667 c.logger = s.Logger.With("remoteAddr", remoteAddr, "login", login)
668
669 // If authentication fails, send error reply and close connection
670 if !c.Authenticate(login, encodedPassword) {
671 t := c.NewErrReply(&clientLogin, "Incorrect login.")
672 b, err := t.MarshalBinary()
673 if err != nil {
674 return err
675 }
676 if _, err := rwc.Write(b); err != nil {
677 return err
678 }
679
680 c.logger.Infow("Login failed", "clientVersion", fmt.Sprintf("%x", c.Version))
681
682 return nil
683 }
684
685 if clientLogin.GetField(FieldUserIconID).Data != nil {
686 c.Icon = clientLogin.GetField(FieldUserIconID).Data
687 }
688
689 c.Account = c.Server.Accounts[login]
690
691 if clientLogin.GetField(FieldUserName).Data != nil {
692 if c.Authorize(accessAnyName) {
693 c.UserName = clientLogin.GetField(FieldUserName).Data
694 } else {
695 c.UserName = []byte(c.Account.Name)
696 }
697 }
698
699 if c.Authorize(accessDisconUser) {
700 c.Flags = []byte{0, 2}
701 }
702
703 s.outbox <- c.NewReply(&clientLogin,
704 NewField(FieldVersion, []byte{0x00, 0xbe}),
705 NewField(FieldCommunityBannerID, []byte{0, 0}),
706 NewField(FieldServerName, []byte(s.Config.Name)),
707 )
708
709 // Send user access privs so client UI knows how to behave
710 c.Server.outbox <- *NewTransaction(TranUserAccess, c.ID, NewField(FieldUserAccess, c.Account.Access[:]))
711
712 // Accounts with accessNoAgreement do not receive the server agreement on login. The behavior is different between
713 // client versions. For 1.2.3 client, we do not send TranShowAgreement. For other client versions, we send
714 // TranShowAgreement but with the NoServerAgreement field set to 1.
715 if c.Authorize(accessNoAgreement) {
716 // If client version is nil, then the client uses the 1.2.3 login behavior
717 if c.Version != nil {
718 c.Server.outbox <- *NewTransaction(TranShowAgreement, c.ID, NewField(FieldNoServerAgreement, []byte{1}))
719 }
720 } else {
721 c.Server.outbox <- *NewTransaction(TranShowAgreement, c.ID, NewField(FieldData, s.Agreement))
722 }
723
724 // If the client has provided a username as part of the login, we can infer that it is using the 1.2.3 login
725 // flow and not the 1.5+ flow.
726 if len(c.UserName) != 0 {
727 // Add the client username to the logger. For 1.5+ clients, we don't have this information yet as it comes as
728 // part of TranAgreed
729 c.logger = c.logger.With("name", string(c.UserName))
730
731 c.logger.Infow("Login successful", "clientVersion", "Not sent (probably 1.2.3)")
732
733 // Notify other clients on the server that the new user has logged in. For 1.5+ clients we don't have this
734 // information yet, so we do it in TranAgreed instead
735 for _, t := range c.notifyOthers(
736 *NewTransaction(
737 TranNotifyChangeUser, nil,
738 NewField(FieldUserName, c.UserName),
739 NewField(FieldUserID, *c.ID),
740 NewField(FieldUserIconID, c.Icon),
741 NewField(FieldUserFlags, c.Flags),
742 ),
743 ) {
744 c.Server.outbox <- t
745 }
746 }
747
748 c.Server.Stats.ConnectionCounter += 1
749 if len(s.Clients) > c.Server.Stats.ConnectionPeak {
750 c.Server.Stats.ConnectionPeak = len(s.Clients)
751 }
752
753 // Scan for new transactions and handle them as they come in.
754 for scanner.Scan() {
755 // Make a new []byte slice and copy the scanner bytes to it. This is critical to avoid a data race as the
756 // scanner re-uses the buffer for subsequent scans.
757 buf := make([]byte, len(scanner.Bytes()))
758 copy(buf, scanner.Bytes())
759
760 var t Transaction
761 if _, err := t.Write(buf); err != nil {
762 return err
763 }
764
765 if err := c.handleTransaction(t); err != nil {
766 c.logger.Errorw("Error handling transaction", "err", err)
767 }
768 }
769 return nil
770 }
771
772 func (s *Server) NewPrivateChat(cc *ClientConn) []byte {
773 s.PrivateChatsMu.Lock()
774 defer s.PrivateChatsMu.Unlock()
775
776 randID := make([]byte, 4)
777 rand.Read(randID)
778 data := binary.BigEndian.Uint32(randID)
779
780 s.PrivateChats[data] = &PrivateChat{
781 ClientConn: make(map[uint16]*ClientConn),
782 }
783 s.PrivateChats[data].ClientConn[cc.uint16ID()] = cc
784
785 return randID
786 }
787
788 const dlFldrActionSendFile = 1
789 const dlFldrActionResumeFile = 2
790 const dlFldrActionNextFile = 3
791
792 // handleFileTransfer receives a client net.Conn from the file transfer server, performs the requested transfer type, then closes the connection
793 func (s *Server) handleFileTransfer(ctx context.Context, rwc io.ReadWriter) error {
794 defer dontPanic(s.Logger)
795
796 txBuf := make([]byte, 16)
797 if _, err := io.ReadFull(rwc, txBuf); err != nil {
798 return err
799 }
800
801 var t transfer
802 if _, err := t.Write(txBuf); err != nil {
803 return err
804 }
805
806 defer func() {
807 s.mux.Lock()
808 delete(s.fileTransfers, t.ReferenceNumber)
809 s.mux.Unlock()
810
811 // Wait a few seconds before closing the connection: this is a workaround for problems
812 // observed with Windows clients where the client must initiate close of the TCP connection before
813 // the server does. This is gross and seems unnecessary. TODO: Revisit?
814 time.Sleep(3 * time.Second)
815 }()
816
817 s.mux.Lock()
818 fileTransfer, ok := s.fileTransfers[t.ReferenceNumber]
819 s.mux.Unlock()
820 if !ok {
821 return errors.New("invalid transaction ID")
822 }
823
824 defer func() {
825 fileTransfer.ClientConn.transfersMU.Lock()
826 delete(fileTransfer.ClientConn.transfers[fileTransfer.Type], t.ReferenceNumber)
827 fileTransfer.ClientConn.transfersMU.Unlock()
828 }()
829
830 rLogger := s.Logger.With(
831 "remoteAddr", ctx.Value(contextKeyReq).(requestCtx).remoteAddr,
832 "login", fileTransfer.ClientConn.Account.Login,
833 "name", string(fileTransfer.ClientConn.UserName),
834 )
835
836 fullPath, err := readPath(s.Config.FileRoot, fileTransfer.FilePath, fileTransfer.FileName)
837 if err != nil {
838 return err
839 }
840
841 switch fileTransfer.Type {
842 case bannerDownload:
843 if err := s.bannerDownload(rwc); err != nil {
844 return err
845 }
846 case FileDownload:
847 s.Stats.DownloadCounter += 1
848 s.Stats.DownloadsInProgress += 1
849 defer func() {
850 s.Stats.DownloadsInProgress -= 1
851 }()
852
853 var dataOffset int64
854 if fileTransfer.fileResumeData != nil {
855 dataOffset = int64(binary.BigEndian.Uint32(fileTransfer.fileResumeData.ForkInfoList[0].DataSize[:]))
856 }
857
858 fw, err := newFileWrapper(s.FS, fullPath, 0)
859 if err != nil {
860 return err
861 }
862
863 rLogger.Infow("File download started", "filePath", fullPath)
864
865 // if file transfer options are included, that means this is a "quick preview" request from a 1.5+ client
866 if fileTransfer.options == nil {
867 _, err = io.Copy(rwc, fw.ffo)
868 if err != nil {
869 return err
870 }
871 }
872
873 file, err := fw.dataForkReader()
874 if err != nil {
875 return err
876 }
877
878 br := bufio.NewReader(file)
879 if _, err := br.Discard(int(dataOffset)); err != nil {
880 return err
881 }
882
883 if _, err = io.Copy(rwc, io.TeeReader(br, fileTransfer.bytesSentCounter)); err != nil {
884 return err
885 }
886
887 // if the client requested to resume transfer, do not send the resource fork header, or it will be appended into the fileWrapper data
888 if fileTransfer.fileResumeData == nil {
889 err = binary.Write(rwc, binary.BigEndian, fw.rsrcForkHeader())
890 if err != nil {
891 return err
892 }
893 }
894
895 rFile, err := fw.rsrcForkFile()
896 if err != nil {
897 return nil
898 }
899
900 if _, err = io.Copy(rwc, io.TeeReader(rFile, fileTransfer.bytesSentCounter)); err != nil {
901 return err
902 }
903
904 case FileUpload:
905 s.Stats.UploadCounter += 1
906 s.Stats.UploadsInProgress += 1
907 defer func() { s.Stats.UploadsInProgress -= 1 }()
908
909 var file *os.File
910
911 // A file upload has three possible cases:
912 // 1) Upload a new file
913 // 2) Resume a partially transferred file
914 // 3) Replace a fully uploaded file
915 // We have to infer which case applies by inspecting what is already on the filesystem
916
917 // 1) Check for existing file:
918 _, err = os.Stat(fullPath)
919 if err == nil {
920 return errors.New("existing file found at " + fullPath)
921 }
922 if errors.Is(err, fs.ErrNotExist) {
923 // If not found, open or create a new .incomplete file
924 file, err = os.OpenFile(fullPath+incompleteFileSuffix, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0644)
925 if err != nil {
926 return err
927 }
928 }
929
930 f, err := newFileWrapper(s.FS, fullPath, 0)
931 if err != nil {
932 return err
933 }
934
935 rLogger.Infow("File upload started", "dstFile", fullPath)
936
937 rForkWriter := io.Discard
938 iForkWriter := io.Discard
939 if s.Config.PreserveResourceForks {
940 rForkWriter, err = f.rsrcForkWriter()
941 if err != nil {
942 return err
943 }
944
945 iForkWriter, err = f.infoForkWriter()
946 if err != nil {
947 return err
948 }
949 }
950
951 if err := receiveFile(rwc, file, rForkWriter, iForkWriter, fileTransfer.bytesSentCounter); err != nil {
952 s.Logger.Error(err)
953 }
954
955 if err := file.Close(); err != nil {
956 return err
957 }
958
959 if err := s.FS.Rename(fullPath+".incomplete", fullPath); err != nil {
960 return err
961 }
962
963 rLogger.Infow("File upload complete", "dstFile", fullPath)
964
965 case FolderDownload:
966 s.Stats.DownloadCounter += 1
967 s.Stats.DownloadsInProgress += 1
968 defer func() { s.Stats.DownloadsInProgress -= 1 }()
969
970 // Folder Download flow:
971 // 1. Get filePath from the transfer
972 // 2. Iterate over files
973 // 3. For each fileWrapper:
974 // Send fileWrapper header to client
975 // The client can reply in 3 ways:
976 //
977 // 1. If type is an odd number (unknown type?), or fileWrapper download for the current fileWrapper is completed:
978 // client sends []byte{0x00, 0x03} to tell the server to continue to the next fileWrapper
979 //
980 // 2. If download of a fileWrapper is to be resumed:
981 // client sends:
982 // []byte{0x00, 0x02} // download folder action
983 // [2]byte // Resume data size
984 // []byte fileWrapper resume data (see myField_FileResumeData)
985 //
986 // 3. Otherwise, download of the fileWrapper is requested and client sends []byte{0x00, 0x01}
987 //
988 // When download is requested (case 2 or 3), server replies with:
989 // [4]byte - fileWrapper size
990 // []byte - Flattened File Object
991 //
992 // After every fileWrapper download, client could request next fileWrapper with:
993 // []byte{0x00, 0x03}
994 //
995 // This notifies the server to send the next item header
996
997 basePathLen := len(fullPath)
998
999 rLogger.Infow("Start folder download", "path", fullPath)
1000
1001 nextAction := make([]byte, 2)
1002 if _, err := io.ReadFull(rwc, nextAction); err != nil {
1003 return err
1004 }
1005
1006 i := 0
1007 err = filepath.Walk(fullPath+"/", func(path string, info os.FileInfo, err error) error {
1008 s.Stats.DownloadCounter += 1
1009 i += 1
1010
1011 if err != nil {
1012 return err
1013 }
1014
1015 // skip dot files
1016 if strings.HasPrefix(info.Name(), ".") {
1017 return nil
1018 }
1019
1020 hlFile, err := newFileWrapper(s.FS, path, 0)
1021 if err != nil {
1022 return err
1023 }
1024
1025 subPath := path[basePathLen+1:]
1026 rLogger.Debugw("Sending fileheader", "i", i, "path", path, "fullFilePath", fullPath, "subPath", subPath, "IsDir", info.IsDir())
1027
1028 if i == 1 {
1029 return nil
1030 }
1031
1032 fileHeader := NewFileHeader(subPath, info.IsDir())
1033 if _, err := io.Copy(rwc, &fileHeader); err != nil {
1034 return fmt.Errorf("error sending file header: %w", err)
1035 }
1036
1037 // Read the client's Next Action request
1038 if _, err := io.ReadFull(rwc, nextAction); err != nil {
1039 return err
1040 }
1041
1042 rLogger.Debugw("Client folder download action", "action", fmt.Sprintf("%X", nextAction[0:2]))
1043
1044 var dataOffset int64
1045
1046 switch nextAction[1] {
1047 case dlFldrActionResumeFile:
1048 // get size of resumeData
1049 resumeDataByteLen := make([]byte, 2)
1050 if _, err := io.ReadFull(rwc, resumeDataByteLen); err != nil {
1051 return err
1052 }
1053
1054 resumeDataLen := binary.BigEndian.Uint16(resumeDataByteLen)
1055 resumeDataBytes := make([]byte, resumeDataLen)
1056 if _, err := io.ReadFull(rwc, resumeDataBytes); err != nil {
1057 return err
1058 }
1059
1060 var frd FileResumeData
1061 if err := frd.UnmarshalBinary(resumeDataBytes); err != nil {
1062 return err
1063 }
1064 dataOffset = int64(binary.BigEndian.Uint32(frd.ForkInfoList[0].DataSize[:]))
1065 case dlFldrActionNextFile:
1066 // client asked to skip this file
1067 return nil
1068 }
1069
1070 if info.IsDir() {
1071 return nil
1072 }
1073
1074 rLogger.Infow("File download started",
1075 "fileName", info.Name(),
1076 "TransferSize", fmt.Sprintf("%x", hlFile.ffo.TransferSize(dataOffset)),
1077 )
1078
1079 // Send file size to client
1080 if _, err := rwc.Write(hlFile.ffo.TransferSize(dataOffset)); err != nil {
1081 s.Logger.Error(err)
1082 return err
1083 }
1084
1085 // Send ffo bytes to client
1086 _, err = io.Copy(rwc, hlFile.ffo)
1087 if err != nil {
1088 return err
1089 }
1090
1091 file, err := s.FS.Open(path)
1092 if err != nil {
1093 return err
1094 }
1095
1096 // wr := bufio.NewWriterSize(rwc, 1460)
1097 if _, err = io.Copy(rwc, io.TeeReader(file, fileTransfer.bytesSentCounter)); err != nil {
1098 return err
1099 }
1100
1101 if nextAction[1] != 2 && hlFile.ffo.FlatFileHeader.ForkCount[1] == 3 {
1102 err = binary.Write(rwc, binary.BigEndian, hlFile.rsrcForkHeader())
1103 if err != nil {
1104 return err
1105 }
1106
1107 rFile, err := hlFile.rsrcForkFile()
1108 if err != nil {
1109 return err
1110 }
1111
1112 if _, err = io.Copy(rwc, io.TeeReader(rFile, fileTransfer.bytesSentCounter)); err != nil {
1113 return err
1114 }
1115 }
1116
1117 // Read the client's Next Action request. This is always 3, I think?
1118 if _, err := io.ReadFull(rwc, nextAction); err != nil {
1119 return err
1120 }
1121
1122 return nil
1123 })
1124
1125 if err != nil {
1126 return err
1127 }
1128
1129 case FolderUpload:
1130 s.Stats.UploadCounter += 1
1131 s.Stats.UploadsInProgress += 1
1132 defer func() { s.Stats.UploadsInProgress -= 1 }()
1133 rLogger.Infow(
1134 "Folder upload started",
1135 "dstPath", fullPath,
1136 "TransferSize", binary.BigEndian.Uint32(fileTransfer.TransferSize),
1137 "FolderItemCount", fileTransfer.FolderItemCount,
1138 )
1139
1140 // Check if the target folder exists. If not, create it.
1141 if _, err := s.FS.Stat(fullPath); os.IsNotExist(err) {
1142 if err := s.FS.Mkdir(fullPath, 0777); err != nil {
1143 return err
1144 }
1145 }
1146
1147 // Begin the folder upload flow by sending the "next file action" to client
1148 if _, err := rwc.Write([]byte{0, dlFldrActionNextFile}); err != nil {
1149 return err
1150 }
1151
1152 fileSize := make([]byte, 4)
1153
1154 for i := 0; i < fileTransfer.ItemCount(); i++ {
1155 s.Stats.UploadCounter += 1
1156
1157 var fu folderUpload
1158 if _, err := io.ReadFull(rwc, fu.DataSize[:]); err != nil {
1159 return err
1160 }
1161 if _, err := io.ReadFull(rwc, fu.IsFolder[:]); err != nil {
1162 return err
1163 }
1164 if _, err := io.ReadFull(rwc, fu.PathItemCount[:]); err != nil {
1165 return err
1166 }
1167
1168 fu.FileNamePath = make([]byte, binary.BigEndian.Uint16(fu.DataSize[:])-4) // -4 to subtract the path separator bytes
1169
1170 if _, err := io.ReadFull(rwc, fu.FileNamePath); err != nil {
1171 return err
1172 }
1173
1174 rLogger.Infow(
1175 "Folder upload continued",
1176 "FormattedPath", fu.FormattedPath(),
1177 "IsFolder", fmt.Sprintf("%x", fu.IsFolder),
1178 "PathItemCount", binary.BigEndian.Uint16(fu.PathItemCount[:]),
1179 )
1180
1181 if fu.IsFolder == [2]byte{0, 1} {
1182 if _, err := os.Stat(filepath.Join(fullPath, fu.FormattedPath())); os.IsNotExist(err) {
1183 if err := os.Mkdir(filepath.Join(fullPath, fu.FormattedPath()), 0777); err != nil {
1184 return err
1185 }
1186 }
1187
1188 // Tell client to send next file
1189 if _, err := rwc.Write([]byte{0, dlFldrActionNextFile}); err != nil {
1190 return err
1191 }
1192 } else {
1193 nextAction := dlFldrActionSendFile
1194
1195 // Check if we have the full file already. If so, send dlFldrAction_NextFile to client to skip.
1196 _, err = os.Stat(filepath.Join(fullPath, fu.FormattedPath()))
1197 if err != nil && !errors.Is(err, fs.ErrNotExist) {
1198 return err
1199 }
1200 if err == nil {
1201 nextAction = dlFldrActionNextFile
1202 }
1203
1204 // Check if we have a partial file already. If so, send dlFldrAction_ResumeFile to client to resume upload.
1205 incompleteFile, err := os.Stat(filepath.Join(fullPath, fu.FormattedPath()+incompleteFileSuffix))
1206 if err != nil && !errors.Is(err, fs.ErrNotExist) {
1207 return err
1208 }
1209 if err == nil {
1210 nextAction = dlFldrActionResumeFile
1211 }
1212
1213 if _, err := rwc.Write([]byte{0, uint8(nextAction)}); err != nil {
1214 return err
1215 }
1216
1217 switch nextAction {
1218 case dlFldrActionNextFile:
1219 continue
1220 case dlFldrActionResumeFile:
1221 offset := make([]byte, 4)
1222 binary.BigEndian.PutUint32(offset, uint32(incompleteFile.Size()))
1223
1224 file, err := os.OpenFile(fullPath+"/"+fu.FormattedPath()+incompleteFileSuffix, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
1225 if err != nil {
1226 return err
1227 }
1228
1229 fileResumeData := NewFileResumeData([]ForkInfoList{*NewForkInfoList(offset)})
1230
1231 b, _ := fileResumeData.BinaryMarshal()
1232
1233 bs := make([]byte, 2)
1234 binary.BigEndian.PutUint16(bs, uint16(len(b)))
1235
1236 if _, err := rwc.Write(append(bs, b...)); err != nil {
1237 return err
1238 }
1239
1240 if _, err := io.ReadFull(rwc, fileSize); err != nil {
1241 return err
1242 }
1243
1244 if err := receiveFile(rwc, file, io.Discard, io.Discard, fileTransfer.bytesSentCounter); err != nil {
1245 s.Logger.Error(err)
1246 }
1247
1248 err = os.Rename(fullPath+"/"+fu.FormattedPath()+".incomplete", fullPath+"/"+fu.FormattedPath())
1249 if err != nil {
1250 return err
1251 }
1252
1253 case dlFldrActionSendFile:
1254 if _, err := io.ReadFull(rwc, fileSize); err != nil {
1255 return err
1256 }
1257
1258 filePath := filepath.Join(fullPath, fu.FormattedPath())
1259
1260 hlFile, err := newFileWrapper(s.FS, filePath, 0)
1261 if err != nil {
1262 return err
1263 }
1264
1265 rLogger.Infow("Starting file transfer", "path", filePath, "fileNum", i+1, "fileSize", binary.BigEndian.Uint32(fileSize))
1266
1267 incWriter, err := hlFile.incFileWriter()
1268 if err != nil {
1269 return err
1270 }
1271
1272 rForkWriter := io.Discard
1273 iForkWriter := io.Discard
1274 if s.Config.PreserveResourceForks {
1275 iForkWriter, err = hlFile.infoForkWriter()
1276 if err != nil {
1277 return err
1278 }
1279
1280 rForkWriter, err = hlFile.rsrcForkWriter()
1281 if err != nil {
1282 return err
1283 }
1284 }
1285 if err := receiveFile(rwc, incWriter, rForkWriter, iForkWriter, fileTransfer.bytesSentCounter); err != nil {
1286 return err
1287 }
1288
1289 if err := os.Rename(filePath+".incomplete", filePath); err != nil {
1290 return err
1291 }
1292 }
1293
1294 // Tell client to send next fileWrapper
1295 if _, err := rwc.Write([]byte{0, dlFldrActionNextFile}); err != nil {
1296 return err
1297 }
1298 }
1299 }
1300 rLogger.Infof("Folder upload complete")
1301 }
1302
1303 return nil
1304 }
Friendship Quest remix of mobius, a hotline server in go #cli