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

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