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

   1 package hotline
   2
   3 import (
   4         "encoding/binary"
   5         "io"
   6         "slices"
   7 )
   8
   9 // User flags are stored as a 2 byte bitmap and represent various user states
  10 const (
  11         UserFlagAway        = 0 // User is away
  12         UserFlagAdmin       = 1 // User is admin
  13         UserFlagRefusePM    = 2 // User refuses private messages
  14         UserFlagRefusePChat = 3 // User refuses private chat
  15 )
  16
  17 // FieldOptions flags are sent from v1.5+ clients as part of TranAgreed
  18 const (
  19         refusePM     = 0 // User has "Refuse private messages" pref set
  20         refuseChat   = 1 // User has "Refuse private chat" pref set
  21         autoResponse = 2 // User has "Automatic response" pref set
  22 )
  23
  24 type User struct {
  25         ID    []byte // Size 2
  26         Icon  []byte // Size 2
  27         Flags []byte // Size 2
  28         Name  string // Variable length user name
  29 }
  30
  31 func (u *User) Read(p []byte) (int, error) {
  32         nameLen := make([]byte, 2)
  33         binary.BigEndian.PutUint16(nameLen, uint16(len(u.Name)))
  34
  35         if len(u.Icon) == 4 {
  36                 u.Icon = u.Icon[2:]
  37         }
  38
  39         if len(u.Flags) == 4 {
  40                 u.Flags = u.Flags[2:]
  41         }
  42
  43         out := append(u.ID[:2], u.Icon[:2]...)
  44         out = append(out, u.Flags[:2]...)
  45         out = append(out, nameLen...)
  46         out = append(out, u.Name...)
  47
  48         return copy(p, slices.Concat(
  49                 u.ID,
  50                 u.Icon,
  51                 u.Flags,
  52                 nameLen,
  53                 []byte(u.Name),
  54         )), io.EOF
  55 }
  56
  57 func (u *User) Write(p []byte) (int, error) {
  58         namelen := int(binary.BigEndian.Uint16(p[6:8]))
  59         u.ID = p[0:2]
  60         u.Icon = p[2:4]
  61         u.Flags = p[4:6]
  62         u.Name = string(p[8 : 8+namelen])
  63
  64         return 8 + namelen, nil
  65 }
  66
  67 // decodeString decodes an obfuscated user string from a client
  68 // e.g. 98 8a 9a 8c 8b => "guest"
  69 func decodeString(obfuText []byte) (clearText string) {
  70         for _, char := range obfuText {
  71                 clearText += string(rune(255 - uint(char)))
  72         }
  73         return clearText
  74 }
  75
  76 // encodeString takes []byte s containing cleartext and rotates by 255 into obfuscated cleartext.
  77 // The Hotline protocol uses this format for sending passwords over network.
  78 // Not secure, but hey, it was the 90s!
  79 func encodeString(clearText []byte) []byte {
  80         obfuText := make([]byte, len(clearText))
  81         for i := 0; i < len(clearText); i++ {
  82                 obfuText[i] = 255 - clearText[i]
  83         }
  84         return obfuText
  85 }