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

   1 package hotline
   2
   3 import (
   4         "bytes"
   5         "encoding/binary"
   6         "errors"
   7         "fmt"
   8         "gopkg.in/yaml.v3"
   9         "io/ioutil"
  10         "math/big"
  11         "os"
  12         "path"
  13         "path/filepath"
  14         "sort"
  15         "strings"
  16         "time"
  17 )
  18
  19 type TransactionType struct {
  20         Handler        func(*ClientConn, *Transaction) ([]Transaction, error) // function for handling the transaction type
  21         Name           string                                                 // Name of transaction as it will appear in logging
  22         RequiredFields []requiredField
  23 }
  24
  25 var TransactionHandlers = map[uint16]TransactionType{
  26         // Server initiated
  27         tranChatMsg: {
  28                 Name: "tranChatMsg",
  29         },
  30         // Server initiated
  31         tranNotifyChangeUser: {
  32                 Name: "tranNotifyChangeUser",
  33         },
  34         tranError: {
  35                 Name: "tranError",
  36         },
  37         tranShowAgreement: {
  38                 Name: "tranShowAgreement",
  39         },
  40         tranUserAccess: {
  41                 Name: "tranUserAccess",
  42         },
  43         tranNotifyDeleteUser: {
  44                 Name: "tranNotifyDeleteUser",
  45         },
  46         tranAgreed: {
  47                 Name:    "tranAgreed",
  48                 Handler: HandleTranAgreed,
  49         },
  50         tranChatSend: {
  51                 Name:    "tranChatSend",
  52                 Handler: HandleChatSend,
  53                 RequiredFields: []requiredField{
  54                         {
  55                                 ID:     fieldData,
  56                                 minLen: 0,
  57                         },
  58                 },
  59         },
  60         tranDelNewsArt: {
  61                 Name:    "tranDelNewsArt",
  62                 Handler: HandleDelNewsArt,
  63         },
  64         tranDelNewsItem: {
  65                 Name:    "tranDelNewsItem",
  66                 Handler: HandleDelNewsItem,
  67         },
  68         tranDeleteFile: {
  69                 Name:    "tranDeleteFile",
  70                 Handler: HandleDeleteFile,
  71         },
  72         tranDeleteUser: {
  73                 Name:    "tranDeleteUser",
  74                 Handler: HandleDeleteUser,
  75         },
  76         tranDisconnectUser: {
  77                 Name:    "tranDisconnectUser",
  78                 Handler: HandleDisconnectUser,
  79         },
  80         tranDownloadFile: {
  81                 Name:    "tranDownloadFile",
  82                 Handler: HandleDownloadFile,
  83         },
  84         tranDownloadFldr: {
  85                 Name:    "tranDownloadFldr",
  86                 Handler: HandleDownloadFolder,
  87         },
  88         tranGetClientInfoText: {
  89                 Name:    "tranGetClientInfoText",
  90                 Handler: HandleGetClientInfoText,
  91         },
  92         tranGetFileInfo: {
  93                 Name:    "tranGetFileInfo",
  94                 Handler: HandleGetFileInfo,
  95         },
  96         tranGetFileNameList: {
  97                 Name:    "tranGetFileNameList",
  98                 Handler: HandleGetFileNameList,
  99         },
 100         tranGetMsgs: {
 101                 Name:    "tranGetMsgs",
 102                 Handler: HandleGetMsgs,
 103         },
 104         tranGetNewsArtData: {
 105                 Name:    "tranGetNewsArtData",
 106                 Handler: HandleGetNewsArtData,
 107         },
 108         tranGetNewsArtNameList: {
 109                 Name:    "tranGetNewsArtNameList",
 110                 Handler: HandleGetNewsArtNameList,
 111         },
 112         tranGetNewsCatNameList: {
 113                 Name:    "tranGetNewsCatNameList",
 114                 Handler: HandleGetNewsCatNameList,
 115         },
 116         tranGetUser: {
 117                 Name:    "tranGetUser",
 118                 Handler: HandleGetUser,
 119         },
 120         tranGetUserNameList: {
 121                 Name:    "tranHandleGetUserNameList",
 122                 Handler: HandleGetUserNameList,
 123         },
 124         tranInviteNewChat: {
 125                 Name:    "tranInviteNewChat",
 126                 Handler: HandleInviteNewChat,
 127         },
 128         tranInviteToChat: {
 129                 Name:    "tranInviteToChat",
 130                 Handler: HandleInviteToChat,
 131         },
 132         tranJoinChat: {
 133                 Name:    "tranJoinChat",
 134                 Handler: HandleJoinChat,
 135         },
 136         tranKeepAlive: {
 137                 Name:    "tranKeepAlive",
 138                 Handler: HandleKeepAlive,
 139         },
 140         tranLeaveChat: {
 141                 Name:    "tranJoinChat",
 142                 Handler: HandleLeaveChat,
 143         },
 144         tranListUsers: {
 145                 Name:    "tranListUsers",
 146                 Handler: HandleListUsers,
 147         },
 148         tranMoveFile: {
 149                 Name:    "tranMoveFile",
 150                 Handler: HandleMoveFile,
 151         },
 152         tranNewFolder: {
 153                 Name:    "tranNewFolder",
 154                 Handler: HandleNewFolder,
 155         },
 156         tranNewNewsCat: {
 157                 Name:    "tranNewNewsCat",
 158                 Handler: HandleNewNewsCat,
 159         },
 160         tranNewNewsFldr: {
 161                 Name:    "tranNewNewsFldr",
 162                 Handler: HandleNewNewsFldr,
 163         },
 164         tranNewUser: {
 165                 Name:    "tranNewUser",
 166                 Handler: HandleNewUser,
 167         },
 168         tranUpdateUser: {
 169                 Name:    "tranUpdateUser",
 170                 Handler: HandleUpdateUser,
 171         },
 172         tranOldPostNews: {
 173                 Name:    "tranOldPostNews",
 174                 Handler: HandleTranOldPostNews,
 175         },
 176         tranPostNewsArt: {
 177                 Name:    "tranPostNewsArt",
 178                 Handler: HandlePostNewsArt,
 179         },
 180         tranRejectChatInvite: {
 181                 Name:    "tranRejectChatInvite",
 182                 Handler: HandleRejectChatInvite,
 183         },
 184         tranSendInstantMsg: {
 185                 Name:    "tranSendInstantMsg",
 186                 Handler: HandleSendInstantMsg,
 187                 RequiredFields: []requiredField{
 188                         {
 189                                 ID:     fieldData,
 190                                 minLen: 0,
 191                         },
 192                         {
 193                                 ID: fieldUserID,
 194                         },
 195                 },
 196         },
 197         tranSetChatSubject: {
 198                 Name:    "tranSetChatSubject",
 199                 Handler: HandleSetChatSubject,
 200         },
 201         tranMakeFileAlias: {
 202                 Name:    "tranMakeFileAlias",
 203                 Handler: HandleMakeAlias,
 204                 RequiredFields: []requiredField{
 205                         {ID: fieldFileName, minLen: 1},
 206                         {ID: fieldFilePath, minLen: 1},
 207                         {ID: fieldFileNewPath, minLen: 1},
 208                 },
 209         },
 210         tranSetClientUserInfo: {
 211                 Name:    "tranSetClientUserInfo",
 212                 Handler: HandleSetClientUserInfo,
 213         },
 214         tranSetFileInfo: {
 215                 Name:    "tranSetFileInfo",
 216                 Handler: HandleSetFileInfo,
 217         },
 218         tranSetUser: {
 219                 Name:    "tranSetUser",
 220                 Handler: HandleSetUser,
 221         },
 222         tranUploadFile: {
 223                 Name:    "tranUploadFile",
 224                 Handler: HandleUploadFile,
 225         },
 226         tranUploadFldr: {
 227                 Name:    "tranUploadFldr",
 228                 Handler: HandleUploadFolder,
 229         },
 230         tranUserBroadcast: {
 231                 Name:    "tranUserBroadcast",
 232                 Handler: HandleUserBroadcast,
 233         },
 234         tranDownloadBanner: {
 235                 Name:    "tranDownloadBanner",
 236                 Handler: HandleDownloadBanner,
 237         },
 238 }
 239
 240 func HandleChatSend(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 241         if !authorize(cc.Account.Access, accessSendChat) {
 242                 res = append(res, cc.NewErrReply(t, "You are not allowed to participate in chat."))
 243                 return res, err
 244         }
 245
 246         // Truncate long usernames
 247         trunc := fmt.Sprintf("%13s", cc.UserName)
 248         formattedMsg := fmt.Sprintf("\r%.14s:  %s", trunc, t.GetField(fieldData).Data)
 249
 250         // By holding the option key, Hotline chat allows users to send /me formatted messages like:
 251         // *** Halcyon does stuff
 252         // This is indicated by the presence of the optional field fieldChatOptions in the transaction payload
 253         if t.GetField(fieldChatOptions).Data != nil {
 254                 formattedMsg = fmt.Sprintf("\r*** %s %s", cc.UserName, t.GetField(fieldData).Data)
 255         }
 256
 257         chatID := t.GetField(fieldChatID).Data
 258         // a non-nil chatID indicates the message belongs to a private chat
 259         if chatID != nil {
 260                 chatInt := binary.BigEndian.Uint32(chatID)
 261                 privChat := cc.Server.PrivateChats[chatInt]
 262
 263                 clients := sortedClients(privChat.ClientConn)
 264
 265                 // send the message to all connected clients of the private chat
 266                 for _, c := range clients {
 267                         res = append(res, *NewTransaction(
 268                                 tranChatMsg,
 269                                 c.ID,
 270                                 NewField(fieldChatID, chatID),
 271                                 NewField(fieldData, []byte(formattedMsg)),
 272                         ))
 273                 }
 274                 return res, err
 275         }
 276
 277         for _, c := range sortedClients(cc.Server.Clients) {
 278                 // Filter out clients that do not have the read chat permission
 279                 if authorize(c.Account.Access, accessReadChat) {
 280                         res = append(res, *NewTransaction(tranChatMsg, c.ID, NewField(fieldData, []byte(formattedMsg))))
 281                 }
 282         }
 283
 284         return res, err
 285 }
 286
 287 // HandleSendInstantMsg sends instant message to the user on the current server.
 288 // Fields used in the request:
 289 //      103     User ID
 290 //      113     Options
 291 //              One of the following values:
 292 //              - User message (myOpt_UserMessage = 1)
 293 //              - Refuse message (myOpt_RefuseMessage = 2)
 294 //              - Refuse chat (myOpt_RefuseChat  = 3)
 295 //              - Automatic response (myOpt_AutomaticResponse = 4)"
 296 //      101     Data    Optional
 297 //      214     Quoting message Optional
 298 //
 299 // Fields used in the reply:
 300 // None
 301 func HandleSendInstantMsg(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 302         msg := t.GetField(fieldData)
 303         ID := t.GetField(fieldUserID)
 304
 305         reply := NewTransaction(
 306                 tranServerMsg,
 307                 &ID.Data,
 308                 NewField(fieldData, msg.Data),
 309                 NewField(fieldUserName, cc.UserName),
 310                 NewField(fieldUserID, *cc.ID),
 311                 NewField(fieldOptions, []byte{0, 1}),
 312         )
 313
 314         // Later versions of Hotline include the original message in the fieldQuotingMsg field so
 315         //  the receiving client can display both the received message and what it is in reply to
 316         if t.GetField(fieldQuotingMsg).Data != nil {
 317                 reply.Fields = append(reply.Fields, NewField(fieldQuotingMsg, t.GetField(fieldQuotingMsg).Data))
 318         }
 319
 320         res = append(res, *reply)
 321
 322         id, _ := byteToInt(ID.Data)
 323         otherClient, ok := cc.Server.Clients[uint16(id)]
 324         if !ok {
 325                 return res, errors.New("invalid client ID")
 326         }
 327
 328         // Respond with auto reply if other client has it enabled
 329         if len(otherClient.AutoReply) > 0 {
 330                 res = append(res,
 331                         *NewTransaction(
 332                                 tranServerMsg,
 333                                 cc.ID,
 334                                 NewField(fieldData, otherClient.AutoReply),
 335                                 NewField(fieldUserName, otherClient.UserName),
 336                                 NewField(fieldUserID, *otherClient.ID),
 337                                 NewField(fieldOptions, []byte{0, 1}),
 338                         ),
 339                 )
 340         }
 341
 342         res = append(res, cc.NewReply(t))
 343
 344         return res, err
 345 }
 346
 347 func HandleGetFileInfo(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 348         fileName := t.GetField(fieldFileName).Data
 349         filePath := t.GetField(fieldFilePath).Data
 350
 351         fullFilePath, err := readPath(cc.Server.Config.FileRoot, filePath, fileName)
 352         if err != nil {
 353                 return res, err
 354         }
 355
 356         fw, err := newFileWrapper(cc.Server.FS, fullFilePath, 0)
 357         if err != nil {
 358                 return res, err
 359         }
 360
 361         res = append(res, cc.NewReply(t,
 362                 NewField(fieldFileName, []byte(fw.name)),
 363                 NewField(fieldFileTypeString, fw.ffo.FlatFileInformationFork.friendlyType()),
 364                 NewField(fieldFileCreatorString, fw.ffo.FlatFileInformationFork.friendlyCreator()),
 365                 NewField(fieldFileComment, fw.ffo.FlatFileInformationFork.Comment),
 366                 NewField(fieldFileType, fw.ffo.FlatFileInformationFork.TypeSignature),
 367                 NewField(fieldFileCreateDate, fw.ffo.FlatFileInformationFork.CreateDate),
 368                 NewField(fieldFileModifyDate, fw.ffo.FlatFileInformationFork.ModifyDate),
 369                 NewField(fieldFileSize, fw.totalSize()),
 370         ))
 371         return res, err
 372 }
 373
 374 // HandleSetFileInfo updates a file or folder name and/or comment from the Get Info window
 375 // Fields used in the request:
 376 // * 201        File name
 377 // * 202        File path       Optional
 378 // * 211        File new name   Optional
 379 // * 210        File comment    Optional
 380 // Fields used in the reply:    None
 381 func HandleSetFileInfo(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 382         fileName := t.GetField(fieldFileName).Data
 383         filePath := t.GetField(fieldFilePath).Data
 384
 385         fullFilePath, err := readPath(cc.Server.Config.FileRoot, filePath, fileName)
 386         if err != nil {
 387                 return res, err
 388         }
 389
 390         fi, err := cc.Server.FS.Stat(fullFilePath)
 391         if err != nil {
 392                 return res, err
 393         }
 394
 395         hlFile, err := newFileWrapper(cc.Server.FS, fullFilePath, 0)
 396         if err != nil {
 397                 return res, err
 398         }
 399         if t.GetField(fieldFileComment).Data != nil {
 400                 switch mode := fi.Mode(); {
 401                 case mode.IsDir():
 402                         if !authorize(cc.Account.Access, accessSetFolderComment) {
 403                                 res = append(res, cc.NewErrReply(t, "You are not allowed to set comments for folders."))
 404                                 return res, err
 405                         }
 406                 case mode.IsRegular():
 407                         if !authorize(cc.Account.Access, accessSetFileComment) {
 408                                 res = append(res, cc.NewErrReply(t, "You are not allowed to set comments for files."))
 409                                 return res, err
 410                         }
 411                 }
 412
 413                 if err := hlFile.ffo.FlatFileInformationFork.setComment(t.GetField(fieldFileComment).Data); err != nil {
 414                         return res, err
 415                 }
 416                 w, err := hlFile.infoForkWriter()
 417                 if err != nil {
 418                         return res, err
 419                 }
 420                 _, err = w.Write(hlFile.ffo.FlatFileInformationFork.MarshalBinary())
 421                 if err != nil {
 422                         return res, err
 423                 }
 424         }
 425
 426         fullNewFilePath, err := readPath(cc.Server.Config.FileRoot, filePath, t.GetField(fieldFileNewName).Data)
 427         if err != nil {
 428                 return nil, err
 429         }
 430
 431         fileNewName := t.GetField(fieldFileNewName).Data
 432
 433         if fileNewName != nil {
 434                 switch mode := fi.Mode(); {
 435                 case mode.IsDir():
 436                         if !authorize(cc.Account.Access, accessRenameFolder) {
 437                                 res = append(res, cc.NewErrReply(t, "You are not allowed to rename folders."))
 438                                 return res, err
 439                         }
 440                         err = os.Rename(fullFilePath, fullNewFilePath)
 441                         if os.IsNotExist(err) {
 442                                 res = append(res, cc.NewErrReply(t, "Cannot rename folder "+string(fileName)+" because it does not exist or cannot be found."))
 443                                 return res, err
 444                         }
 445                 case mode.IsRegular():
 446                         if !authorize(cc.Account.Access, accessRenameFile) {
 447                                 res = append(res, cc.NewErrReply(t, "You are not allowed to rename files."))
 448                                 return res, err
 449                         }
 450                         fileDir, err := readPath(cc.Server.Config.FileRoot, filePath, []byte{})
 451                         if err != nil {
 452                                 return nil, err
 453                         }
 454                         hlFile.name = string(fileNewName)
 455                         err = hlFile.move(fileDir)
 456                         if os.IsNotExist(err) {
 457                                 res = append(res, cc.NewErrReply(t, "Cannot rename file "+string(fileName)+" because it does not exist or cannot be found."))
 458                                 return res, err
 459                         }
 460                         if err != nil {
 461                                 panic(err)
 462                         }
 463                 }
 464         }
 465
 466         res = append(res, cc.NewReply(t))
 467         return res, err
 468 }
 469
 470 // HandleDeleteFile deletes a file or folder
 471 // Fields used in the request:
 472 // * 201        File name
 473 // * 202        File path
 474 // Fields used in the reply: none
 475 func HandleDeleteFile(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 476         fileName := t.GetField(fieldFileName).Data
 477         filePath := t.GetField(fieldFilePath).Data
 478
 479         fullFilePath, err := readPath(cc.Server.Config.FileRoot, filePath, fileName)
 480         if err != nil {
 481                 return res, err
 482         }
 483
 484         hlFile, err := newFileWrapper(cc.Server.FS, fullFilePath, 0)
 485         if err != nil {
 486                 return res, err
 487         }
 488
 489         fi, err := hlFile.dataFile()
 490         if err != nil {
 491                 res = append(res, cc.NewErrReply(t, "Cannot delete file "+string(fileName)+" because it does not exist or cannot be found."))
 492                 return res, nil
 493         }
 494
 495         switch mode := fi.Mode(); {
 496         case mode.IsDir():
 497                 if !authorize(cc.Account.Access, accessDeleteFolder) {
 498                         res = append(res, cc.NewErrReply(t, "You are not allowed to delete folders."))
 499                         return res, err
 500                 }
 501         case mode.IsRegular():
 502                 if !authorize(cc.Account.Access, accessDeleteFile) {
 503                         res = append(res, cc.NewErrReply(t, "You are not allowed to delete files."))
 504                         return res, err
 505                 }
 506         }
 507
 508         if err := hlFile.delete(); err != nil {
 509                 return res, err
 510         }
 511
 512         res = append(res, cc.NewReply(t))
 513         return res, err
 514 }
 515
 516 // HandleMoveFile moves files or folders. Note: seemingly not documented
 517 func HandleMoveFile(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 518         fileName := string(t.GetField(fieldFileName).Data)
 519
 520         filePath, err := readPath(cc.Server.Config.FileRoot, t.GetField(fieldFilePath).Data, t.GetField(fieldFileName).Data)
 521         if err != nil {
 522                 return res, err
 523         }
 524
 525         fileNewPath, err := readPath(cc.Server.Config.FileRoot, t.GetField(fieldFileNewPath).Data, nil)
 526         if err != nil {
 527                 return res, err
 528         }
 529
 530         cc.logger.Infow("Move file", "src", filePath+"/"+fileName, "dst", fileNewPath+"/"+fileName)
 531
 532         hlFile, err := newFileWrapper(cc.Server.FS, filePath, 0)
 533         if err != nil {
 534                 return res, err
 535         }
 536
 537         fi, err := hlFile.dataFile()
 538         if err != nil {
 539                 res = append(res, cc.NewErrReply(t, "Cannot delete file "+fileName+" because it does not exist or cannot be found."))
 540                 return res, err
 541         }
 542         if err != nil {
 543                 return res, err
 544         }
 545         switch mode := fi.Mode(); {
 546         case mode.IsDir():
 547                 if !authorize(cc.Account.Access, accessMoveFolder) {
 548                         res = append(res, cc.NewErrReply(t, "You are not allowed to move folders."))
 549                         return res, err
 550                 }
 551         case mode.IsRegular():
 552                 if !authorize(cc.Account.Access, accessMoveFile) {
 553                         res = append(res, cc.NewErrReply(t, "You are not allowed to move files."))
 554                         return res, err
 555                 }
 556         }
 557         if err := hlFile.move(fileNewPath); err != nil {
 558                 return res, err
 559         }
 560         // TODO: handle other possible errors; e.g. fileWrapper delete fails due to fileWrapper permission issue
 561
 562         res = append(res, cc.NewReply(t))
 563         return res, err
 564 }
 565
 566 func HandleNewFolder(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 567         if !authorize(cc.Account.Access, accessCreateFolder) {
 568                 res = append(res, cc.NewErrReply(t, "You are not allowed to create folders."))
 569                 return res, err
 570         }
 571         folderName := string(t.GetField(fieldFileName).Data)
 572
 573         folderName = path.Join("/", folderName)
 574
 575         var subPath string
 576
 577         // fieldFilePath is only present for nested paths
 578         if t.GetField(fieldFilePath).Data != nil {
 579                 var newFp FilePath
 580                 err := newFp.UnmarshalBinary(t.GetField(fieldFilePath).Data)
 581                 if err != nil {
 582                         return nil, err
 583                 }
 584
 585                 for _, pathItem := range newFp.Items {
 586                         subPath = filepath.Join("/", subPath, string(pathItem.Name))
 587                 }
 588         }
 589         newFolderPath := path.Join(cc.Server.Config.FileRoot, subPath, folderName)
 590
 591         // TODO: check path and folder name lengths
 592
 593         if _, err := cc.Server.FS.Stat(newFolderPath); !os.IsNotExist(err) {
 594                 msg := fmt.Sprintf("Cannot create folder \"%s\" because there is already a file or folder with that name.", folderName)
 595                 return []Transaction{cc.NewErrReply(t, msg)}, nil
 596         }
 597
 598         // TODO: check for disallowed characters to maintain compatibility for original client
 599
 600         if err := cc.Server.FS.Mkdir(newFolderPath, 0777); err != nil {
 601                 msg := fmt.Sprintf("Cannot create folder \"%s\" because an error occurred.", folderName)
 602                 return []Transaction{cc.NewErrReply(t, msg)}, nil
 603         }
 604
 605         res = append(res, cc.NewReply(t))
 606         return res, err
 607 }
 608
 609 func HandleSetUser(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 610         if !authorize(cc.Account.Access, accessModifyUser) {
 611                 res = append(res, cc.NewErrReply(t, "You are not allowed to modify accounts."))
 612                 return res, err
 613         }
 614
 615         login := DecodeUserString(t.GetField(fieldUserLogin).Data)
 616         userName := string(t.GetField(fieldUserName).Data)
 617
 618         newAccessLvl := t.GetField(fieldUserAccess).Data
 619
 620         account := cc.Server.Accounts[login]
 621         account.Access = &newAccessLvl
 622         account.Name = userName
 623
 624         // If the password field is cleared in the Hotline edit user UI, the SetUser transaction does
 625         // not include fieldUserPassword
 626         if t.GetField(fieldUserPassword).Data == nil {
 627                 account.Password = hashAndSalt([]byte(""))
 628         }
 629         if len(t.GetField(fieldUserPassword).Data) > 1 {
 630                 account.Password = hashAndSalt(t.GetField(fieldUserPassword).Data)
 631         }
 632
 633         out, err := yaml.Marshal(&account)
 634         if err != nil {
 635                 return res, err
 636         }
 637         if err := os.WriteFile(cc.Server.ConfigDir+"Users/"+login+".yaml", out, 0666); err != nil {
 638                 return res, err
 639         }
 640
 641         // Notify connected clients logged in as the user of the new access level
 642         for _, c := range cc.Server.Clients {
 643                 if c.Account.Login == login {
 644                         // Note: comment out these two lines to test server-side deny messages
 645                         newT := NewTransaction(tranUserAccess, c.ID, NewField(fieldUserAccess, newAccessLvl))
 646                         res = append(res, *newT)
 647
 648                         flagBitmap := big.NewInt(int64(binary.BigEndian.Uint16(*c.Flags)))
 649                         if authorize(c.Account.Access, accessDisconUser) {
 650                                 flagBitmap.SetBit(flagBitmap, userFlagAdmin, 1)
 651                         } else {
 652                                 flagBitmap.SetBit(flagBitmap, userFlagAdmin, 0)
 653                         }
 654                         binary.BigEndian.PutUint16(*c.Flags, uint16(flagBitmap.Int64()))
 655
 656                         c.Account.Access = account.Access
 657
 658                         cc.sendAll(
 659                                 tranNotifyChangeUser,
 660                                 NewField(fieldUserID, *c.ID),
 661                                 NewField(fieldUserFlags, *c.Flags),
 662                                 NewField(fieldUserName, c.UserName),
 663                                 NewField(fieldUserIconID, *c.Icon),
 664                         )
 665                 }
 666         }
 667
 668         res = append(res, cc.NewReply(t))
 669         return res, err
 670 }
 671
 672 func HandleGetUser(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 673         if !authorize(cc.Account.Access, accessOpenUser) {
 674                 res = append(res, cc.NewErrReply(t, "You are not allowed to view accounts."))
 675                 return res, err
 676         }
 677
 678         account := cc.Server.Accounts[string(t.GetField(fieldUserLogin).Data)]
 679         if account == nil {
 680                 res = append(res, cc.NewErrReply(t, "Account does not exist."))
 681                 return res, err
 682         }
 683
 684         res = append(res, cc.NewReply(t,
 685                 NewField(fieldUserName, []byte(account.Name)),
 686                 NewField(fieldUserLogin, negateString(t.GetField(fieldUserLogin).Data)),
 687                 NewField(fieldUserPassword, []byte(account.Password)),
 688                 NewField(fieldUserAccess, *account.Access),
 689         ))
 690         return res, err
 691 }
 692
 693 func HandleListUsers(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 694         if !authorize(cc.Account.Access, accessOpenUser) {
 695                 res = append(res, cc.NewErrReply(t, "You are not allowed to view accounts."))
 696                 return res, err
 697         }
 698
 699         var userFields []Field
 700         for _, acc := range cc.Server.Accounts {
 701                 b := make([]byte, 0, 100)
 702                 n, err := acc.Read(b)
 703                 if err != nil {
 704                         return res, err
 705                 }
 706
 707                 userFields = append(userFields, NewField(fieldData, b[:n]))
 708         }
 709
 710         res = append(res, cc.NewReply(t, userFields...))
 711         return res, err
 712 }
 713
 714 // HandleUpdateUser is used by the v1.5+ multi-user editor to perform account editing for multiple users at a time.
 715 // An update can be a mix of these actions:
 716 // * Create user
 717 // * Delete user
 718 // * Modify user (including renaming the account login)
 719 //
 720 // The Transaction sent by the client includes one data field per user that was modified.  This data field in turn
 721 // contains another data field encoded in its payload with a varying number of sub fields depending on which action is
 722 // performed.  This seems to be the only place in the Hotline protocol where a data field contains another data field.
 723 func HandleUpdateUser(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 724         for _, field := range t.Fields {
 725                 subFields, err := ReadFields(field.Data[0:2], field.Data[2:])
 726                 if err != nil {
 727                         return res, err
 728                 }
 729
 730                 if len(subFields) == 1 {
 731                         login := DecodeUserString(getField(fieldData, &subFields).Data)
 732                         cc.logger.Infow("DeleteUser", "login", login)
 733
 734                         if !authorize(cc.Account.Access, accessDeleteUser) {
 735                                 res = append(res, cc.NewErrReply(t, "You are not allowed to delete accounts."))
 736                                 return res, err
 737                         }
 738
 739                         if err := cc.Server.DeleteUser(login); err != nil {
 740                                 return res, err
 741                         }
 742                         continue
 743                 }
 744
 745                 login := DecodeUserString(getField(fieldUserLogin, &subFields).Data)
 746
 747                 // check if the login dataFile; if so, we know we are updating an existing user
 748                 if acc, ok := cc.Server.Accounts[login]; ok {
 749                         cc.logger.Infow("UpdateUser", "login", login)
 750
 751                         // account dataFile, so this is an update action
 752                         if !authorize(cc.Account.Access, accessModifyUser) {
 753                                 res = append(res, cc.NewErrReply(t, "You are not allowed to modify accounts."))
 754                                 return res, err
 755                         }
 756
 757                         if getField(fieldUserPassword, &subFields) != nil {
 758                                 newPass := getField(fieldUserPassword, &subFields).Data
 759                                 acc.Password = hashAndSalt(newPass)
 760                         } else {
 761                                 acc.Password = hashAndSalt([]byte(""))
 762                         }
 763
 764                         if getField(fieldUserAccess, &subFields) != nil {
 765                                 acc.Access = &getField(fieldUserAccess, &subFields).Data
 766                         }
 767
 768                         err = cc.Server.UpdateUser(
 769                                 DecodeUserString(getField(fieldData, &subFields).Data),
 770                                 DecodeUserString(getField(fieldUserLogin, &subFields).Data),
 771                                 string(getField(fieldUserName, &subFields).Data),
 772                                 acc.Password,
 773                                 *acc.Access,
 774                         )
 775                         if err != nil {
 776                                 return res, err
 777                         }
 778                 } else {
 779                         cc.logger.Infow("CreateUser", "login", login)
 780
 781                         if !authorize(cc.Account.Access, accessCreateUser) {
 782                                 res = append(res, cc.NewErrReply(t, "You are not allowed to create new accounts."))
 783                                 return res, err
 784                         }
 785
 786                         err := cc.Server.NewUser(
 787                                 login,
 788                                 string(getField(fieldUserName, &subFields).Data),
 789                                 string(getField(fieldUserPassword, &subFields).Data),
 790                                 getField(fieldUserAccess, &subFields).Data,
 791                         )
 792                         if err != nil {
 793                                 return []Transaction{}, err
 794                         }
 795                 }
 796         }
 797
 798         res = append(res, cc.NewReply(t))
 799         return res, err
 800 }
 801
 802 // HandleNewUser creates a new user account
 803 func HandleNewUser(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 804         if !authorize(cc.Account.Access, accessCreateUser) {
 805                 res = append(res, cc.NewErrReply(t, "You are not allowed to create new accounts."))
 806                 return res, err
 807         }
 808
 809         login := DecodeUserString(t.GetField(fieldUserLogin).Data)
 810
 811         // If the account already dataFile, reply with an error
 812         if _, ok := cc.Server.Accounts[login]; ok {
 813                 res = append(res, cc.NewErrReply(t, "Cannot create account "+login+" because there is already an account with that login."))
 814                 return res, err
 815         }
 816
 817         if err := cc.Server.NewUser(
 818                 login,
 819                 string(t.GetField(fieldUserName).Data),
 820                 string(t.GetField(fieldUserPassword).Data),
 821                 t.GetField(fieldUserAccess).Data,
 822         ); err != nil {
 823                 return []Transaction{}, err
 824         }
 825
 826         res = append(res, cc.NewReply(t))
 827         return res, err
 828 }
 829
 830 func HandleDeleteUser(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 831         if !authorize(cc.Account.Access, accessDeleteUser) {
 832                 res = append(res, cc.NewErrReply(t, "You are not allowed to delete accounts."))
 833                 return res, err
 834         }
 835
 836         // TODO: Handle case where account doesn't exist; e.g. delete race condition
 837         login := DecodeUserString(t.GetField(fieldUserLogin).Data)
 838
 839         if err := cc.Server.DeleteUser(login); err != nil {
 840                 return res, err
 841         }
 842
 843         res = append(res, cc.NewReply(t))
 844         return res, err
 845 }
 846
 847 // HandleUserBroadcast sends an Administrator Message to all connected clients of the server
 848 func HandleUserBroadcast(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 849         if !authorize(cc.Account.Access, accessBroadcast) {
 850                 res = append(res, cc.NewErrReply(t, "You are not allowed to send broadcast messages."))
 851                 return res, err
 852         }
 853
 854         cc.sendAll(
 855                 tranServerMsg,
 856                 NewField(fieldData, t.GetField(tranGetMsgs).Data),
 857                 NewField(fieldChatOptions, []byte{0}),
 858         )
 859
 860         res = append(res, cc.NewReply(t))
 861         return res, err
 862 }
 863
 864 func byteToInt(bytes []byte) (int, error) {
 865         switch len(bytes) {
 866         case 2:
 867                 return int(binary.BigEndian.Uint16(bytes)), nil
 868         case 4:
 869                 return int(binary.BigEndian.Uint32(bytes)), nil
 870         }
 871
 872         return 0, errors.New("unknown byte length")
 873 }
 874
 875 // HandleGetClientInfoText returns user information for the specific user.
 876 //
 877 // Fields used in the request:
 878 // 103  User ID
 879 //
 880 // Fields used in the reply:
 881 // 102  User name
 882 // 101  Data            User info text string
 883 func HandleGetClientInfoText(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 884         if !authorize(cc.Account.Access, accessGetClientInfo) {
 885                 res = append(res, cc.NewErrReply(t, "You are not allowed to get client info."))
 886                 return res, err
 887         }
 888
 889         clientID, _ := byteToInt(t.GetField(fieldUserID).Data)
 890
 891         clientConn := cc.Server.Clients[uint16(clientID)]
 892         if clientConn == nil {
 893                 return append(res, cc.NewErrReply(t, "User not found.")), err
 894         }
 895
 896         res = append(res, cc.NewReply(t,
 897                 NewField(fieldData, []byte(clientConn.String())),
 898                 NewField(fieldUserName, clientConn.UserName),
 899         ))
 900         return res, err
 901 }
 902
 903 func HandleGetUserNameList(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 904         res = append(res, cc.NewReply(t, cc.Server.connectedUsers()...))
 905
 906         return res, err
 907 }
 908
 909 func HandleTranAgreed(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 910         cc.Agreed = true
 911         cc.UserName = t.GetField(fieldUserName).Data
 912         *cc.Icon = t.GetField(fieldUserIconID).Data
 913
 914         cc.logger = cc.logger.With("name", string(cc.UserName))
 915         cc.logger.Infow("Login successful", "clientVersion", fmt.Sprintf("%x", *cc.Version))
 916
 917         options := t.GetField(fieldOptions).Data
 918         optBitmap := big.NewInt(int64(binary.BigEndian.Uint16(options)))
 919
 920         flagBitmap := big.NewInt(int64(binary.BigEndian.Uint16(*cc.Flags)))
 921
 922         // Check refuse private PM option
 923         if optBitmap.Bit(refusePM) == 1 {
 924                 flagBitmap.SetBit(flagBitmap, userFlagRefusePM, 1)
 925                 binary.BigEndian.PutUint16(*cc.Flags, uint16(flagBitmap.Int64()))
 926         }
 927
 928         // Check refuse private chat option
 929         if optBitmap.Bit(refuseChat) == 1 {
 930                 flagBitmap.SetBit(flagBitmap, userFLagRefusePChat, 1)
 931                 binary.BigEndian.PutUint16(*cc.Flags, uint16(flagBitmap.Int64()))
 932         }
 933
 934         // Check auto response
 935         if optBitmap.Bit(autoResponse) == 1 {
 936                 cc.AutoReply = t.GetField(fieldAutomaticResponse).Data
 937         } else {
 938                 cc.AutoReply = []byte{}
 939         }
 940
 941         for _, t := range cc.notifyOthers(
 942                 *NewTransaction(
 943                         tranNotifyChangeUser, nil,
 944                         NewField(fieldUserName, cc.UserName),
 945                         NewField(fieldUserID, *cc.ID),
 946                         NewField(fieldUserIconID, *cc.Icon),
 947                         NewField(fieldUserFlags, *cc.Flags),
 948                 ),
 949         ) {
 950                 cc.Server.outbox <- t
 951         }
 952
 953         if cc.Server.Config.BannerFile != "" {
 954                 cc.Server.outbox <- *NewTransaction(tranServerBanner, cc.ID, NewField(fieldBannerType, []byte("JPEG")))
 955         }
 956
 957         res = append(res, cc.NewReply(t))
 958
 959         return res, err
 960 }
 961
 962 const defaultNewsDateFormat = "Jan02 15:04" // Jun23 20:49
 963 //  "Mon, 02 Jan 2006 15:04:05 MST"
 964
 965 const defaultNewsTemplate = `From %s (%s):
 966
 967 %s
 968
 969 __________________________________________________________`
 970
 971 // HandleTranOldPostNews updates the flat news
 972 // Fields used in this request:
 973 // 101  Data
 974 func HandleTranOldPostNews(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
 975         if !authorize(cc.Account.Access, accessNewsPostArt) {
 976                 res = append(res, cc.NewErrReply(t, "You are not allowed to post news."))
 977                 return res, err
 978         }
 979
 980         cc.Server.flatNewsMux.Lock()
 981         defer cc.Server.flatNewsMux.Unlock()
 982
 983         newsDateTemplate := defaultNewsDateFormat
 984         if cc.Server.Config.NewsDateFormat != "" {
 985                 newsDateTemplate = cc.Server.Config.NewsDateFormat
 986         }
 987
 988         newsTemplate := defaultNewsTemplate
 989         if cc.Server.Config.NewsDelimiter != "" {
 990                 newsTemplate = cc.Server.Config.NewsDelimiter
 991         }
 992
 993         newsPost := fmt.Sprintf(newsTemplate+"\r", cc.UserName, time.Now().Format(newsDateTemplate), t.GetField(fieldData).Data)
 994         newsPost = strings.Replace(newsPost, "\n", "\r", -1)
 995
 996         // update news in memory
 997         cc.Server.FlatNews = append([]byte(newsPost), cc.Server.FlatNews...)
 998
 999         // update news on disk
1000         if err := ioutil.WriteFile(cc.Server.ConfigDir+"MessageBoard.txt", cc.Server.FlatNews, 0644); err != nil {
1001                 return res, err
1002         }
1003
1004         // Notify all clients of updated news
1005         cc.sendAll(
1006                 tranNewMsg,
1007                 NewField(fieldData, []byte(newsPost)),
1008         )
1009
1010         res = append(res, cc.NewReply(t))
1011         return res, err
1012 }
1013
1014 func HandleDisconnectUser(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1015         if !authorize(cc.Account.Access, accessDisconUser) {
1016                 res = append(res, cc.NewErrReply(t, "You are not allowed to disconnect users."))
1017                 return res, err
1018         }
1019
1020         clientConn := cc.Server.Clients[binary.BigEndian.Uint16(t.GetField(fieldUserID).Data)]
1021
1022         if authorize(clientConn.Account.Access, accessCannotBeDiscon) {
1023                 res = append(res, cc.NewErrReply(t, clientConn.Account.Login+" is not allowed to be disconnected."))
1024                 return res, err
1025         }
1026
1027         if err := clientConn.Connection.Close(); err != nil {
1028                 return res, err
1029         }
1030
1031         res = append(res, cc.NewReply(t))
1032         return res, err
1033 }
1034
1035 // HandleGetNewsCatNameList returns a list of news categories for a path
1036 // Fields used in the request:
1037 // 325  News path       (Optional)
1038 func HandleGetNewsCatNameList(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1039         if !authorize(cc.Account.Access, accessNewsReadArt) {
1040                 res = append(res, cc.NewErrReply(t, "You are not allowed to read news."))
1041                 return res, err
1042         }
1043
1044         pathStrs := ReadNewsPath(t.GetField(fieldNewsPath).Data)
1045         cats := cc.Server.GetNewsCatByPath(pathStrs)
1046
1047         // To store the keys in slice in sorted order
1048         keys := make([]string, len(cats))
1049         i := 0
1050         for k := range cats {
1051                 keys[i] = k
1052                 i++
1053         }
1054         sort.Strings(keys)
1055
1056         var fieldData []Field
1057         for _, k := range keys {
1058                 cat := cats[k]
1059                 b, _ := cat.MarshalBinary()
1060                 fieldData = append(fieldData, NewField(
1061                         fieldNewsCatListData15,
1062                         b,
1063                 ))
1064         }
1065
1066         res = append(res, cc.NewReply(t, fieldData...))
1067         return res, err
1068 }
1069
1070 func HandleNewNewsCat(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1071         if !authorize(cc.Account.Access, accessNewsCreateCat) {
1072                 res = append(res, cc.NewErrReply(t, "You are not allowed to create news categories."))
1073                 return res, err
1074         }
1075
1076         name := string(t.GetField(fieldNewsCatName).Data)
1077         pathStrs := ReadNewsPath(t.GetField(fieldNewsPath).Data)
1078
1079         cats := cc.Server.GetNewsCatByPath(pathStrs)
1080         cats[name] = NewsCategoryListData15{
1081                 Name:     name,
1082                 Type:     []byte{0, 3},
1083                 Articles: map[uint32]*NewsArtData{},
1084                 SubCats:  make(map[string]NewsCategoryListData15),
1085         }
1086
1087         if err := cc.Server.writeThreadedNews(); err != nil {
1088                 return res, err
1089         }
1090         res = append(res, cc.NewReply(t))
1091         return res, err
1092 }
1093
1094 // Fields used in the request:
1095 // 322  News category name
1096 // 325  News path
1097 func HandleNewNewsFldr(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1098         if !authorize(cc.Account.Access, accessNewsCreateFldr) {
1099                 res = append(res, cc.NewErrReply(t, "You are not allowed to create news folders."))
1100                 return res, err
1101         }
1102
1103         name := string(t.GetField(fieldFileName).Data)
1104         pathStrs := ReadNewsPath(t.GetField(fieldNewsPath).Data)
1105
1106         cc.logger.Infof("Creating new news folder %s", name)
1107
1108         cats := cc.Server.GetNewsCatByPath(pathStrs)
1109         cats[name] = NewsCategoryListData15{
1110                 Name:     name,
1111                 Type:     []byte{0, 2},
1112                 Articles: map[uint32]*NewsArtData{},
1113                 SubCats:  make(map[string]NewsCategoryListData15),
1114         }
1115         if err := cc.Server.writeThreadedNews(); err != nil {
1116                 return res, err
1117         }
1118         res = append(res, cc.NewReply(t))
1119         return res, err
1120 }
1121
1122 // Fields used in the request:
1123 // 325  News path       Optional
1124 //
1125 // Reply fields:
1126 // 321  News article list data  Optional
1127 func HandleGetNewsArtNameList(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1128         if !authorize(cc.Account.Access, accessNewsReadArt) {
1129                 res = append(res, cc.NewErrReply(t, "You are not allowed to read news."))
1130                 return res, err
1131         }
1132         pathStrs := ReadNewsPath(t.GetField(fieldNewsPath).Data)
1133
1134         var cat NewsCategoryListData15
1135         cats := cc.Server.ThreadedNews.Categories
1136
1137         for _, fp := range pathStrs {
1138                 cat = cats[fp]
1139                 cats = cats[fp].SubCats
1140         }
1141
1142         nald := cat.GetNewsArtListData()
1143
1144         res = append(res, cc.NewReply(t, NewField(fieldNewsArtListData, nald.Payload())))
1145         return res, err
1146 }
1147
1148 func HandleGetNewsArtData(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1149         if !authorize(cc.Account.Access, accessNewsReadArt) {
1150                 res = append(res, cc.NewErrReply(t, "You are not allowed to read news."))
1151                 return res, err
1152         }
1153
1154         // Request fields
1155         // 325  News fp
1156         // 326  News article ID
1157         // 327  News article data flavor
1158
1159         pathStrs := ReadNewsPath(t.GetField(fieldNewsPath).Data)
1160
1161         var cat NewsCategoryListData15
1162         cats := cc.Server.ThreadedNews.Categories
1163
1164         for _, fp := range pathStrs {
1165                 cat = cats[fp]
1166                 cats = cats[fp].SubCats
1167         }
1168         newsArtID := t.GetField(fieldNewsArtID).Data
1169
1170         convertedArtID := binary.BigEndian.Uint16(newsArtID)
1171
1172         art := cat.Articles[uint32(convertedArtID)]
1173         if art == nil {
1174                 res = append(res, cc.NewReply(t))
1175                 return res, err
1176         }
1177
1178         // Reply fields
1179         // 328  News article title
1180         // 329  News article poster
1181         // 330  News article date
1182         // 331  Previous article ID
1183         // 332  Next article ID
1184         // 335  Parent article ID
1185         // 336  First child article ID
1186         // 327  News article data flavor        "Should be “text/plain”
1187         // 333  News article data       Optional (if data flavor is “text/plain”)
1188
1189         res = append(res, cc.NewReply(t,
1190                 NewField(fieldNewsArtTitle, []byte(art.Title)),
1191                 NewField(fieldNewsArtPoster, []byte(art.Poster)),
1192                 NewField(fieldNewsArtDate, art.Date),
1193                 NewField(fieldNewsArtPrevArt, art.PrevArt),
1194                 NewField(fieldNewsArtNextArt, art.NextArt),
1195                 NewField(fieldNewsArtParentArt, art.ParentArt),
1196                 NewField(fieldNewsArt1stChildArt, art.FirstChildArt),
1197                 NewField(fieldNewsArtDataFlav, []byte("text/plain")),
1198                 NewField(fieldNewsArtData, []byte(art.Data)),
1199         ))
1200         return res, err
1201 }
1202
1203 func HandleDelNewsItem(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1204         // Has multiple access flags: News Delete Folder (37) or News Delete Category (35)
1205         // TODO: Implement
1206
1207         pathStrs := ReadNewsPath(t.GetField(fieldNewsPath).Data)
1208
1209         // TODO: determine if path is a Folder (Bundle) or Category and check for permission
1210
1211         cc.logger.Infof("DelNewsItem %v", pathStrs)
1212
1213         cats := cc.Server.ThreadedNews.Categories
1214
1215         delName := pathStrs[len(pathStrs)-1]
1216         if len(pathStrs) > 1 {
1217                 for _, fp := range pathStrs[0 : len(pathStrs)-1] {
1218                         cats = cats[fp].SubCats
1219                 }
1220         }
1221
1222         delete(cats, delName)
1223
1224         err = cc.Server.writeThreadedNews()
1225         if err != nil {
1226                 return res, err
1227         }
1228
1229         // Reply params: none
1230         res = append(res, cc.NewReply(t))
1231
1232         return res, err
1233 }
1234
1235 func HandleDelNewsArt(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1236         if !authorize(cc.Account.Access, accessNewsDeleteArt) {
1237                 res = append(res, cc.NewErrReply(t, "You are not allowed to delete news articles."))
1238                 return res, err
1239         }
1240
1241         // Request Fields
1242         // 325  News path
1243         // 326  News article ID
1244         // 337  News article – recursive delete       Delete child articles (1) or not (0)
1245         pathStrs := ReadNewsPath(t.GetField(fieldNewsPath).Data)
1246         ID := binary.BigEndian.Uint16(t.GetField(fieldNewsArtID).Data)
1247
1248         // TODO: Delete recursive
1249         cats := cc.Server.GetNewsCatByPath(pathStrs[:len(pathStrs)-1])
1250
1251         catName := pathStrs[len(pathStrs)-1]
1252         cat := cats[catName]
1253
1254         delete(cat.Articles, uint32(ID))
1255
1256         cats[catName] = cat
1257         if err := cc.Server.writeThreadedNews(); err != nil {
1258                 return res, err
1259         }
1260
1261         res = append(res, cc.NewReply(t))
1262         return res, err
1263 }
1264
1265 // Request fields
1266 // 325  News path
1267 // 326  News article ID                                                 ID of the parent article?
1268 // 328  News article title
1269 // 334  News article flags
1270 // 327  News article data flavor                Currently “text/plain”
1271 // 333  News article data
1272 func HandlePostNewsArt(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1273         if !authorize(cc.Account.Access, accessNewsPostArt) {
1274                 res = append(res, cc.NewErrReply(t, "You are not allowed to post news articles."))
1275                 return res, err
1276         }
1277
1278         pathStrs := ReadNewsPath(t.GetField(fieldNewsPath).Data)
1279         cats := cc.Server.GetNewsCatByPath(pathStrs[:len(pathStrs)-1])
1280
1281         catName := pathStrs[len(pathStrs)-1]
1282         cat := cats[catName]
1283
1284         newArt := NewsArtData{
1285                 Title:         string(t.GetField(fieldNewsArtTitle).Data),
1286                 Poster:        string(cc.UserName),
1287                 Date:          toHotlineTime(time.Now()),
1288                 PrevArt:       []byte{0, 0, 0, 0},
1289                 NextArt:       []byte{0, 0, 0, 0},
1290                 ParentArt:     append([]byte{0, 0}, t.GetField(fieldNewsArtID).Data...),
1291                 FirstChildArt: []byte{0, 0, 0, 0},
1292                 DataFlav:      []byte("text/plain"),
1293                 Data:          string(t.GetField(fieldNewsArtData).Data),
1294         }
1295
1296         var keys []int
1297         for k := range cat.Articles {
1298                 keys = append(keys, int(k))
1299         }
1300
1301         nextID := uint32(1)
1302         if len(keys) > 0 {
1303                 sort.Ints(keys)
1304                 prevID := uint32(keys[len(keys)-1])
1305                 nextID = prevID + 1
1306
1307                 binary.BigEndian.PutUint32(newArt.PrevArt, prevID)
1308
1309                 // Set next article ID
1310                 binary.BigEndian.PutUint32(cat.Articles[prevID].NextArt, nextID)
1311         }
1312
1313         // Update parent article with first child reply
1314         parentID := binary.BigEndian.Uint16(t.GetField(fieldNewsArtID).Data)
1315         if parentID != 0 {
1316                 parentArt := cat.Articles[uint32(parentID)]
1317
1318                 if bytes.Equal(parentArt.FirstChildArt, []byte{0, 0, 0, 0}) {
1319                         binary.BigEndian.PutUint32(parentArt.FirstChildArt, nextID)
1320                 }
1321         }
1322
1323         cat.Articles[nextID] = &newArt
1324
1325         cats[catName] = cat
1326         if err := cc.Server.writeThreadedNews(); err != nil {
1327                 return res, err
1328         }
1329
1330         res = append(res, cc.NewReply(t))
1331         return res, err
1332 }
1333
1334 // HandleGetMsgs returns the flat news data
1335 func HandleGetMsgs(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1336         if !authorize(cc.Account.Access, accessNewsReadArt) {
1337                 res = append(res, cc.NewErrReply(t, "You are not allowed to read news."))
1338                 return res, err
1339         }
1340
1341         res = append(res, cc.NewReply(t, NewField(fieldData, cc.Server.FlatNews)))
1342
1343         return res, err
1344 }
1345
1346 func HandleDownloadFile(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1347         if !authorize(cc.Account.Access, accessDownloadFile) {
1348                 res = append(res, cc.NewErrReply(t, "You are not allowed to download files."))
1349                 return res, err
1350         }
1351
1352         fileName := t.GetField(fieldFileName).Data
1353         filePath := t.GetField(fieldFilePath).Data
1354         resumeData := t.GetField(fieldFileResumeData).Data
1355
1356         var dataOffset int64
1357         var frd FileResumeData
1358         if resumeData != nil {
1359                 if err := frd.UnmarshalBinary(t.GetField(fieldFileResumeData).Data); err != nil {
1360                         return res, err
1361                 }
1362                 // TODO: handle rsrc fork offset
1363                 dataOffset = int64(binary.BigEndian.Uint32(frd.ForkInfoList[0].DataSize[:]))
1364         }
1365
1366         fullFilePath, err := readPath(cc.Server.Config.FileRoot, filePath, fileName)
1367         if err != nil {
1368                 return res, err
1369         }
1370
1371         hlFile, err := newFileWrapper(cc.Server.FS, fullFilePath, dataOffset)
1372         if err != nil {
1373                 return res, err
1374         }
1375
1376         xferSize := hlFile.ffo.TransferSize(0)
1377
1378         ft := cc.newFileTransfer(FileDownload, fileName, filePath, xferSize)
1379
1380         // TODO: refactor to remove this
1381         if resumeData != nil {
1382                 var frd FileResumeData
1383                 if err := frd.UnmarshalBinary(t.GetField(fieldFileResumeData).Data); err != nil {
1384                         return res, err
1385                 }
1386                 ft.fileResumeData = &frd
1387         }
1388
1389         // Optional field for when a HL v1.5+ client requests file preview
1390         // Used only for TEXT, JPEG, GIFF, BMP or PICT files
1391         // The value will always be 2
1392         if t.GetField(fieldFileTransferOptions).Data != nil {
1393                 ft.options = t.GetField(fieldFileTransferOptions).Data
1394                 xferSize = hlFile.ffo.FlatFileDataForkHeader.DataSize[:]
1395         }
1396
1397         res = append(res, cc.NewReply(t,
1398                 NewField(fieldRefNum, ft.refNum[:]),
1399                 NewField(fieldWaitingCount, []byte{0x00, 0x00}), // TODO: Implement waiting count
1400                 NewField(fieldTransferSize, xferSize),
1401                 NewField(fieldFileSize, hlFile.ffo.FlatFileDataForkHeader.DataSize[:]),
1402         ))
1403
1404         return res, err
1405 }
1406
1407 // Download all files from the specified folder and sub-folders
1408 func HandleDownloadFolder(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1409         if !authorize(cc.Account.Access, accessDownloadFile) {
1410                 res = append(res, cc.NewErrReply(t, "You are not allowed to download folders."))
1411                 return res, err
1412         }
1413
1414         fullFilePath, err := readPath(cc.Server.Config.FileRoot, t.GetField(fieldFilePath).Data, t.GetField(fieldFileName).Data)
1415         if err != nil {
1416                 return res, err
1417         }
1418
1419         transferSize, err := CalcTotalSize(fullFilePath)
1420         if err != nil {
1421                 return res, err
1422         }
1423         itemCount, err := CalcItemCount(fullFilePath)
1424         if err != nil {
1425                 return res, err
1426         }
1427
1428         fileTransfer := cc.newFileTransfer(FolderDownload, t.GetField(fieldFileName).Data, t.GetField(fieldFilePath).Data, transferSize)
1429
1430         var fp FilePath
1431         err = fp.UnmarshalBinary(t.GetField(fieldFilePath).Data)
1432         if err != nil {
1433                 return res, err
1434         }
1435
1436         res = append(res, cc.NewReply(t,
1437                 NewField(fieldRefNum, fileTransfer.ReferenceNumber),
1438                 NewField(fieldTransferSize, transferSize),
1439                 NewField(fieldFolderItemCount, itemCount),
1440                 NewField(fieldWaitingCount, []byte{0x00, 0x00}), // TODO: Implement waiting count
1441         ))
1442         return res, err
1443 }
1444
1445 // Upload all files from the local folder and its subfolders to the specified path on the server
1446 // Fields used in the request
1447 // 201  File name
1448 // 202  File path
1449 // 108  transfer size   Total size of all items in the folder
1450 // 220  Folder item count
1451 // 204  File transfer options   "Optional Currently set to 1" (TODO: ??)
1452 func HandleUploadFolder(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1453         var fp FilePath
1454         if t.GetField(fieldFilePath).Data != nil {
1455                 if err = fp.UnmarshalBinary(t.GetField(fieldFilePath).Data); err != nil {
1456                         return res, err
1457                 }
1458         }
1459
1460         // Handle special cases for Upload and Drop Box folders
1461         if !authorize(cc.Account.Access, accessUploadAnywhere) {
1462                 if !fp.IsUploadDir() && !fp.IsDropbox() {
1463                         res = append(res, cc.NewErrReply(t, fmt.Sprintf("Cannot accept upload of the folder \"%v\" because you are only allowed to upload to the \"Uploads\" folder.", string(t.GetField(fieldFileName).Data))))
1464                         return res, err
1465                 }
1466         }
1467
1468         fileTransfer := cc.newFileTransfer(FolderUpload,
1469                 t.GetField(fieldFileName).Data,
1470                 t.GetField(fieldFilePath).Data,
1471                 t.GetField(fieldTransferSize).Data,
1472         )
1473
1474         fileTransfer.FolderItemCount = t.GetField(fieldFolderItemCount).Data
1475
1476         res = append(res, cc.NewReply(t, NewField(fieldRefNum, fileTransfer.ReferenceNumber)))
1477         return res, err
1478 }
1479
1480 // HandleUploadFile
1481 // Fields used in the request:
1482 // 201  File name
1483 // 202  File path
1484 // 204  File transfer options   "Optional
1485 // Used only to resume download, currently has value 2"
1486 // 108  File transfer size      "Optional used if download is not resumed"
1487 func HandleUploadFile(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1488         if !authorize(cc.Account.Access, accessUploadFile) {
1489                 res = append(res, cc.NewErrReply(t, "You are not allowed to upload files."))
1490                 return res, err
1491         }
1492
1493         fileName := t.GetField(fieldFileName).Data
1494         filePath := t.GetField(fieldFilePath).Data
1495         transferOptions := t.GetField(fieldFileTransferOptions).Data
1496         transferSize := t.GetField(fieldTransferSize).Data // not sent for resume
1497
1498         var fp FilePath
1499         if filePath != nil {
1500                 if err = fp.UnmarshalBinary(filePath); err != nil {
1501                         return res, err
1502                 }
1503         }
1504
1505         // Handle special cases for Upload and Drop Box folders
1506         if !authorize(cc.Account.Access, accessUploadAnywhere) {
1507                 if !fp.IsUploadDir() && !fp.IsDropbox() {
1508                         res = append(res, cc.NewErrReply(t, fmt.Sprintf("Cannot accept upload of the file \"%v\" because you are only allowed to upload to the \"Uploads\" folder.", string(fileName))))
1509                         return res, err
1510                 }
1511         }
1512         fullFilePath, err := readPath(cc.Server.Config.FileRoot, filePath, fileName)
1513         if err != nil {
1514                 return res, err
1515         }
1516
1517         if _, err := cc.Server.FS.Stat(fullFilePath); err == nil {
1518                 res = append(res, cc.NewErrReply(t, fmt.Sprintf("Cannot accept upload because there is already a file named \"%v\".  Try choosing a different name.", string(fileName))))
1519                 return res, err
1520         }
1521
1522         ft := cc.newFileTransfer(FileUpload, fileName, filePath, transferSize)
1523
1524         replyT := cc.NewReply(t, NewField(fieldRefNum, ft.ReferenceNumber))
1525
1526         // client has requested to resume a partially transferred file
1527         if transferOptions != nil {
1528
1529                 fileInfo, err := cc.Server.FS.Stat(fullFilePath + incompleteFileSuffix)
1530                 if err != nil {
1531                         return res, err
1532                 }
1533
1534                 offset := make([]byte, 4)
1535                 binary.BigEndian.PutUint32(offset, uint32(fileInfo.Size()))
1536
1537                 fileResumeData := NewFileResumeData([]ForkInfoList{
1538                         *NewForkInfoList(offset),
1539                 })
1540
1541                 b, _ := fileResumeData.BinaryMarshal()
1542
1543                 ft.TransferSize = offset
1544
1545                 replyT.Fields = append(replyT.Fields, NewField(fieldFileResumeData, b))
1546         }
1547
1548         res = append(res, replyT)
1549         return res, err
1550 }
1551
1552 func HandleSetClientUserInfo(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1553         var icon []byte
1554         if len(t.GetField(fieldUserIconID).Data) == 4 {
1555                 icon = t.GetField(fieldUserIconID).Data[2:]
1556         } else {
1557                 icon = t.GetField(fieldUserIconID).Data
1558         }
1559         *cc.Icon = icon
1560         cc.UserName = t.GetField(fieldUserName).Data
1561
1562         // the options field is only passed by the client versions > 1.2.3.
1563         options := t.GetField(fieldOptions).Data
1564
1565         if options != nil {
1566                 optBitmap := big.NewInt(int64(binary.BigEndian.Uint16(options)))
1567                 flagBitmap := big.NewInt(int64(binary.BigEndian.Uint16(*cc.Flags)))
1568
1569                 flagBitmap.SetBit(flagBitmap, userFlagRefusePM, optBitmap.Bit(refusePM))
1570                 binary.BigEndian.PutUint16(*cc.Flags, uint16(flagBitmap.Int64()))
1571
1572                 flagBitmap.SetBit(flagBitmap, userFLagRefusePChat, optBitmap.Bit(refuseChat))
1573                 binary.BigEndian.PutUint16(*cc.Flags, uint16(flagBitmap.Int64()))
1574
1575                 // Check auto response
1576                 if optBitmap.Bit(autoResponse) == 1 {
1577                         cc.AutoReply = t.GetField(fieldAutomaticResponse).Data
1578                 } else {
1579                         cc.AutoReply = []byte{}
1580                 }
1581         }
1582
1583         // Notify all clients of updated user info
1584         cc.sendAll(
1585                 tranNotifyChangeUser,
1586                 NewField(fieldUserID, *cc.ID),
1587                 NewField(fieldUserIconID, *cc.Icon),
1588                 NewField(fieldUserFlags, *cc.Flags),
1589                 NewField(fieldUserName, cc.UserName),
1590         )
1591
1592         return res, err
1593 }
1594
1595 // HandleKeepAlive responds to keepalive transactions with an empty reply
1596 // * HL 1.9.2 Client sends keepalive msg every 3 minutes
1597 // * HL 1.2.3 Client doesn't send keepalives
1598 func HandleKeepAlive(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1599         res = append(res, cc.NewReply(t))
1600
1601         return res, err
1602 }
1603
1604 func HandleGetFileNameList(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1605         fullPath, err := readPath(
1606                 cc.Server.Config.FileRoot,
1607                 t.GetField(fieldFilePath).Data,
1608                 nil,
1609         )
1610         if err != nil {
1611                 return res, err
1612         }
1613
1614         var fp FilePath
1615         if t.GetField(fieldFilePath).Data != nil {
1616                 if err = fp.UnmarshalBinary(t.GetField(fieldFilePath).Data); err != nil {
1617                         return res, err
1618                 }
1619         }
1620
1621         // Handle special case for drop box folders
1622         if fp.IsDropbox() && !authorize(cc.Account.Access, accessViewDropBoxes) {
1623                 res = append(res, cc.NewErrReply(t, "You are not allowed to view drop boxes."))
1624                 return res, err
1625         }
1626
1627         fileNames, err := getFileNameList(fullPath)
1628         if err != nil {
1629                 return res, err
1630         }
1631
1632         res = append(res, cc.NewReply(t, fileNames...))
1633
1634         return res, err
1635 }
1636
1637 // =================================
1638 //     Hotline private chat flow
1639 // =================================
1640 // 1. ClientA sends tranInviteNewChat to server with user ID to invite
1641 // 2. Server creates new ChatID
1642 // 3. Server sends tranInviteToChat to invitee
1643 // 4. Server replies to ClientA with new Chat ID
1644 //
1645 // A dialog box pops up in the invitee client with options to accept or decline the invitation.
1646 // If Accepted is clicked:
1647 // 1. ClientB sends tranJoinChat with fieldChatID
1648
1649 // HandleInviteNewChat invites users to new private chat
1650 func HandleInviteNewChat(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1651         if !authorize(cc.Account.Access, accessOpenChat) {
1652                 res = append(res, cc.NewErrReply(t, "You are not allowed to request private chat."))
1653                 return res, err
1654         }
1655
1656         // Client to Invite
1657         targetID := t.GetField(fieldUserID).Data
1658         newChatID := cc.Server.NewPrivateChat(cc)
1659
1660         res = append(res,
1661                 *NewTransaction(
1662                         tranInviteToChat,
1663                         &targetID,
1664                         NewField(fieldChatID, newChatID),
1665                         NewField(fieldUserName, cc.UserName),
1666                         NewField(fieldUserID, *cc.ID),
1667                 ),
1668         )
1669
1670         res = append(res,
1671                 cc.NewReply(t,
1672                         NewField(fieldChatID, newChatID),
1673                         NewField(fieldUserName, cc.UserName),
1674                         NewField(fieldUserID, *cc.ID),
1675                         NewField(fieldUserIconID, *cc.Icon),
1676                         NewField(fieldUserFlags, *cc.Flags),
1677                 ),
1678         )
1679
1680         return res, err
1681 }
1682
1683 func HandleInviteToChat(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1684         if !authorize(cc.Account.Access, accessOpenChat) {
1685                 res = append(res, cc.NewErrReply(t, "You are not allowed to request private chat."))
1686                 return res, err
1687         }
1688
1689         // Client to Invite
1690         targetID := t.GetField(fieldUserID).Data
1691         chatID := t.GetField(fieldChatID).Data
1692
1693         res = append(res,
1694                 *NewTransaction(
1695                         tranInviteToChat,
1696                         &targetID,
1697                         NewField(fieldChatID, chatID),
1698                         NewField(fieldUserName, cc.UserName),
1699                         NewField(fieldUserID, *cc.ID),
1700                 ),
1701         )
1702         res = append(res,
1703                 cc.NewReply(
1704                         t,
1705                         NewField(fieldChatID, chatID),
1706                         NewField(fieldUserName, cc.UserName),
1707                         NewField(fieldUserID, *cc.ID),
1708                         NewField(fieldUserIconID, *cc.Icon),
1709                         NewField(fieldUserFlags, *cc.Flags),
1710                 ),
1711         )
1712
1713         return res, err
1714 }
1715
1716 func HandleRejectChatInvite(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1717         chatID := t.GetField(fieldChatID).Data
1718         chatInt := binary.BigEndian.Uint32(chatID)
1719
1720         privChat := cc.Server.PrivateChats[chatInt]
1721
1722         resMsg := append(cc.UserName, []byte(" declined invitation to chat")...)
1723
1724         for _, c := range sortedClients(privChat.ClientConn) {
1725                 res = append(res,
1726                         *NewTransaction(
1727                                 tranChatMsg,
1728                                 c.ID,
1729                                 NewField(fieldChatID, chatID),
1730                                 NewField(fieldData, resMsg),
1731                         ),
1732                 )
1733         }
1734
1735         return res, err
1736 }
1737
1738 // HandleJoinChat is sent from a v1.8+ Hotline client when the joins a private chat
1739 // Fields used in the reply:
1740 // * 115        Chat subject
1741 // * 300        User name with info (Optional)
1742 // * 300        (more user names with info)
1743 func HandleJoinChat(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1744         chatID := t.GetField(fieldChatID).Data
1745         chatInt := binary.BigEndian.Uint32(chatID)
1746
1747         privChat := cc.Server.PrivateChats[chatInt]
1748
1749         // Send tranNotifyChatChangeUser to current members of the chat to inform of new user
1750         for _, c := range sortedClients(privChat.ClientConn) {
1751                 res = append(res,
1752                         *NewTransaction(
1753                                 tranNotifyChatChangeUser,
1754                                 c.ID,
1755                                 NewField(fieldChatID, chatID),
1756                                 NewField(fieldUserName, cc.UserName),
1757                                 NewField(fieldUserID, *cc.ID),
1758                                 NewField(fieldUserIconID, *cc.Icon),
1759                                 NewField(fieldUserFlags, *cc.Flags),
1760                         ),
1761                 )
1762         }
1763
1764         privChat.ClientConn[cc.uint16ID()] = cc
1765
1766         replyFields := []Field{NewField(fieldChatSubject, []byte(privChat.Subject))}
1767         for _, c := range sortedClients(privChat.ClientConn) {
1768                 user := User{
1769                         ID:    *c.ID,
1770                         Icon:  *c.Icon,
1771                         Flags: *c.Flags,
1772                         Name:  string(c.UserName),
1773                 }
1774
1775                 replyFields = append(replyFields, NewField(fieldUsernameWithInfo, user.Payload()))
1776         }
1777
1778         res = append(res, cc.NewReply(t, replyFields...))
1779         return res, err
1780 }
1781
1782 // HandleLeaveChat is sent from a v1.8+ Hotline client when the user exits a private chat
1783 // Fields used in the request:
1784 //      * 114   fieldChatID
1785 // Reply is not expected.
1786 func HandleLeaveChat(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1787         chatID := t.GetField(fieldChatID).Data
1788         chatInt := binary.BigEndian.Uint32(chatID)
1789
1790         privChat, ok := cc.Server.PrivateChats[chatInt]
1791         if !ok {
1792                 return res, nil
1793         }
1794
1795         delete(privChat.ClientConn, cc.uint16ID())
1796
1797         // Notify members of the private chat that the user has left
1798         for _, c := range sortedClients(privChat.ClientConn) {
1799                 res = append(res,
1800                         *NewTransaction(
1801                                 tranNotifyChatDeleteUser,
1802                                 c.ID,
1803                                 NewField(fieldChatID, chatID),
1804                                 NewField(fieldUserID, *cc.ID),
1805                         ),
1806                 )
1807         }
1808
1809         return res, err
1810 }
1811
1812 // HandleSetChatSubject is sent from a v1.8+ Hotline client when the user sets a private chat subject
1813 // Fields used in the request:
1814 // * 114        Chat ID
1815 // * 115        Chat subject    Chat subject string
1816 // Reply is not expected.
1817 func HandleSetChatSubject(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1818         chatID := t.GetField(fieldChatID).Data
1819         chatInt := binary.BigEndian.Uint32(chatID)
1820
1821         privChat := cc.Server.PrivateChats[chatInt]
1822         privChat.Subject = string(t.GetField(fieldChatSubject).Data)
1823
1824         for _, c := range sortedClients(privChat.ClientConn) {
1825                 res = append(res,
1826                         *NewTransaction(
1827                                 tranNotifyChatSubject,
1828                                 c.ID,
1829                                 NewField(fieldChatID, chatID),
1830                                 NewField(fieldChatSubject, t.GetField(fieldChatSubject).Data),
1831                         ),
1832                 )
1833         }
1834
1835         return res, err
1836 }
1837
1838 // HandleMakeAlias makes a filer alias using the specified path.
1839 // Fields used in the request:
1840 // 201  File name
1841 // 202  File path
1842 // 212  File new path   Destination path
1843 //
1844 // Fields used in the reply:
1845 // None
1846 func HandleMakeAlias(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1847         if !authorize(cc.Account.Access, accessMakeAlias) {
1848                 res = append(res, cc.NewErrReply(t, "You are not allowed to make aliases."))
1849                 return res, err
1850         }
1851         fileName := t.GetField(fieldFileName).Data
1852         filePath := t.GetField(fieldFilePath).Data
1853         fileNewPath := t.GetField(fieldFileNewPath).Data
1854
1855         fullFilePath, err := readPath(cc.Server.Config.FileRoot, filePath, fileName)
1856         if err != nil {
1857                 return res, err
1858         }
1859
1860         fullNewFilePath, err := readPath(cc.Server.Config.FileRoot, fileNewPath, fileName)
1861         if err != nil {
1862                 return res, err
1863         }
1864
1865         cc.logger.Debugw("Make alias", "src", fullFilePath, "dst", fullNewFilePath)
1866
1867         if err := cc.Server.FS.Symlink(fullFilePath, fullNewFilePath); err != nil {
1868                 res = append(res, cc.NewErrReply(t, "Error creating alias"))
1869                 return res, nil
1870         }
1871
1872         res = append(res, cc.NewReply(t))
1873         return res, err
1874 }
1875
1876 func HandleDownloadBanner(cc *ClientConn, t *Transaction) (res []Transaction, err error) {
1877         fi, err := cc.Server.FS.Stat(filepath.Join(cc.Server.ConfigDir, cc.Server.Config.BannerFile))
1878         if err != nil {
1879                 return res, err
1880         }
1881
1882         ft := cc.newFileTransfer(bannerDownload, []byte{}, []byte{}, make([]byte, 4))
1883
1884         binary.BigEndian.PutUint32(ft.TransferSize, uint32(fi.Size()))
1885
1886         res = append(res, cc.NewReply(t,
1887                 NewField(fieldRefNum, ft.refNum[:]),
1888                 NewField(fieldTransferSize, ft.TransferSize),
1889         ))
1890
1891         return res, err
1892 }