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

   1 package hotline
   2
   3 import (
   4         "encoding/binary"
   5         "errors"
   6         "fmt"
   7         "github.com/jhalter/mobius/concat"
   8         "math/rand"
   9 )
  10
  11 const (
  12         tranError          = 0
  13         tranGetMsgs        = 101
  14         tranNewMsg         = 102
  15         tranOldPostNews    = 103
  16         tranServerMsg      = 104
  17         tranChatSend       = 105
  18         tranChatMsg        = 106
  19         tranLogin          = 107
  20         tranSendInstantMsg = 108
  21         tranShowAgreement  = 109
  22         tranDisconnectUser = 110
  23         // tranDisconnectMsg        = 111 TODO: implement friendly disconnect
  24         tranInviteNewChat        = 112
  25         tranInviteToChat         = 113
  26         tranRejectChatInvite     = 114
  27         tranJoinChat             = 115
  28         tranLeaveChat            = 116
  29         tranNotifyChatChangeUser = 117
  30         tranNotifyChatDeleteUser = 118
  31         tranNotifyChatSubject    = 119
  32         tranSetChatSubject       = 120
  33         tranAgreed               = 121
  34         tranServerBanner         = 122
  35         tranGetFileNameList      = 200
  36         tranDownloadFile         = 202
  37         tranUploadFile           = 203
  38         tranNewFolder            = 205
  39         tranDeleteFile           = 204
  40         tranGetFileInfo          = 206
  41         tranSetFileInfo          = 207
  42         tranMoveFile             = 208
  43         tranMakeFileAlias        = 209
  44         tranDownloadFldr         = 210
  45         // tranDownloadInfo         = 211 TODO: implement file transfer queue
  46         tranDownloadBanner     = 212
  47         tranUploadFldr         = 213
  48         tranGetUserNameList    = 300
  49         tranNotifyChangeUser   = 301
  50         tranNotifyDeleteUser   = 302
  51         tranGetClientInfoText  = 303
  52         tranSetClientUserInfo  = 304
  53         tranListUsers          = 348
  54         tranUpdateUser         = 349
  55         tranNewUser            = 350
  56         tranDeleteUser         = 351
  57         tranGetUser            = 352
  58         tranSetUser            = 353
  59         tranUserAccess         = 354
  60         tranUserBroadcast      = 355
  61         tranGetNewsCatNameList = 370
  62         tranGetNewsArtNameList = 371
  63         tranDelNewsItem        = 380
  64         tranNewNewsFldr        = 381
  65         tranNewNewsCat         = 382
  66         tranGetNewsArtData     = 400
  67         tranPostNewsArt        = 410
  68         tranDelNewsArt         = 411
  69         tranKeepAlive          = 500
  70 )
  71
  72 type Transaction struct {
  73         clientID *[]byte
  74
  75         Flags      byte   // Reserved (should be 0)
  76         IsReply    byte   // Request (0) or reply (1)
  77         Type       []byte // Requested operation (user defined)
  78         ID         []byte // Unique transaction ID (must be != 0)
  79         ErrorCode  []byte // Used in the reply (user defined, 0 = no error)
  80         TotalSize  []byte // Total data size for the transaction (all parts)
  81         DataSize   []byte // Size of data in this transaction part. This allows splitting large transactions into smaller parts.
  82         ParamCount []byte // Number of the parameters for this transaction
  83         Fields     []Field
  84 }
  85
  86 func NewTransaction(t int, clientID *[]byte, fields ...Field) *Transaction {
  87         typeSlice := make([]byte, 2)
  88         binary.BigEndian.PutUint16(typeSlice, uint16(t))
  89
  90         idSlice := make([]byte, 4)
  91         binary.BigEndian.PutUint32(idSlice, rand.Uint32())
  92
  93         return &Transaction{
  94                 clientID:  clientID,
  95                 Flags:     0x00,
  96                 IsReply:   0x00,
  97                 Type:      typeSlice,
  98                 ID:        idSlice,
  99                 ErrorCode: []byte{0, 0, 0, 0},
 100                 Fields:    fields,
 101         }
 102 }
 103
 104 // ReadTransaction parses a byte slice into a struct.  The input slice may be shorter or longer
 105 // that the transaction size depending on what was read from the network connection.
 106 func ReadTransaction(buf []byte) (*Transaction, int, error) {
 107         totalSize := binary.BigEndian.Uint32(buf[12:16])
 108
 109         // the buf may include extra bytes that are not part of the transaction
 110         // tranLen represents the length of bytes that are part of the transaction
 111         tranLen := int(20 + totalSize)
 112
 113         if tranLen > len(buf) {
 114                 return nil, 0, errors.New("buflen too small for tranLen")
 115         }
 116         fields, err := ReadFields(buf[20:22], buf[22:tranLen])
 117         if err != nil {
 118                 return nil, 0, err
 119         }
 120
 121         return &Transaction{
 122                 Flags:      buf[0],
 123                 IsReply:    buf[1],
 124                 Type:       buf[2:4],
 125                 ID:         buf[4:8],
 126                 ErrorCode:  buf[8:12],
 127                 TotalSize:  buf[12:16],
 128                 DataSize:   buf[16:20],
 129                 ParamCount: buf[20:22],
 130                 Fields:     fields,
 131         }, tranLen, nil
 132 }
 133
 134 const tranHeaderLen = 20 // fixed length of transaction fields before the variable length fields
 135
 136 // transactionScanner implements bufio.SplitFunc for parsing incoming byte slices into complete tokens
 137 func transactionScanner(data []byte, _ bool) (advance int, token []byte, err error) {
 138         // The bytes that contain the size of a transaction are from 12:16, so we need at least 16 bytes
 139         if len(data) < 16 {
 140                 return 0, nil, nil
 141         }
 142
 143         totalSize := binary.BigEndian.Uint32(data[12:16])
 144
 145         // tranLen represents the length of bytes that are part of the transaction
 146         tranLen := int(tranHeaderLen + totalSize)
 147         if tranLen > len(data) {
 148                 return 0, nil, nil
 149         }
 150
 151         return tranLen, data[0:tranLen], nil
 152 }
 153
 154 const minFieldLen = 4
 155
 156 func ReadFields(paramCount []byte, buf []byte) ([]Field, error) {
 157         paramCountInt := int(binary.BigEndian.Uint16(paramCount))
 158         if paramCountInt > 0 && len(buf) < minFieldLen {
 159                 return []Field{}, fmt.Errorf("invalid field length %v", len(buf))
 160         }
 161
 162         // A Field consists of:
 163         // ID: 2 bytes
 164         // Size: 2 bytes
 165         // Data: FieldSize number of bytes
 166         var fields []Field
 167         for i := 0; i < paramCountInt; i++ {
 168                 if len(buf) < minFieldLen {
 169                         return []Field{}, fmt.Errorf("invalid field length %v", len(buf))
 170                 }
 171                 fieldID := buf[0:2]
 172                 fieldSize := buf[2:4]
 173                 fieldSizeInt := int(binary.BigEndian.Uint16(buf[2:4]))
 174                 expectedLen := minFieldLen + fieldSizeInt
 175                 if len(buf) < expectedLen {
 176                         return []Field{}, fmt.Errorf("field length too short")
 177                 }
 178
 179                 fields = append(fields, Field{
 180                         ID:        fieldID,
 181                         FieldSize: fieldSize,
 182                         Data:      buf[4 : 4+fieldSizeInt],
 183                 })
 184
 185                 buf = buf[fieldSizeInt+4:]
 186         }
 187
 188         if len(buf) != 0 {
 189                 return []Field{}, fmt.Errorf("extra field bytes")
 190         }
 191
 192         return fields, nil
 193 }
 194
 195 func (t *Transaction) MarshalBinary() (data []byte, err error) {
 196         payloadSize := t.Size()
 197
 198         fieldCount := make([]byte, 2)
 199         binary.BigEndian.PutUint16(fieldCount, uint16(len(t.Fields)))
 200
 201         var fieldPayload []byte
 202         for _, field := range t.Fields {
 203                 fieldPayload = append(fieldPayload, field.Payload()...)
 204         }
 205
 206         return concat.Slices(
 207                 []byte{t.Flags, t.IsReply},
 208                 t.Type,
 209                 t.ID,
 210                 t.ErrorCode,
 211                 payloadSize,
 212                 payloadSize, // this is the dataSize field, but seeming the same as totalSize
 213                 fieldCount,
 214                 fieldPayload,
 215         ), err
 216 }
 217
 218 // Size returns the total size of the transaction payload
 219 func (t *Transaction) Size() []byte {
 220         bs := make([]byte, 4)
 221
 222         fieldSize := 0
 223         for _, field := range t.Fields {
 224                 fieldSize += len(field.Data) + 4
 225         }
 226
 227         binary.BigEndian.PutUint32(bs, uint32(fieldSize+2))
 228
 229         return bs
 230 }
 231
 232 func (t *Transaction) GetField(id int) Field {
 233         for _, field := range t.Fields {
 234                 if id == int(binary.BigEndian.Uint16(field.ID)) {
 235                         return field
 236                 }
 237         }
 238
 239         return Field{}
 240 }