vendor/github.com/miekg/dns/format.go

   1 package dns
   2
   3 import (
   4         "net"
   5         "reflect"
   6         "strconv"
   7 )
   8
   9 // NumField returns the number of rdata fields r has.
  10 func NumField(r RR) int {
  11         return reflect.ValueOf(r).Elem().NumField() - 1 // Remove RR_Header
  12 }
  13
  14 // Field returns the rdata field i as a string. Fields are indexed starting from 1.
  15 // RR types that holds slice data, for instance the NSEC type bitmap will return a single
  16 // string where the types are concatenated using a space.
  17 // Accessing non existing fields will cause a panic.
  18 func Field(r RR, i int) string {
  19         if i == 0 {
  20                 return ""
  21         }
  22         d := reflect.ValueOf(r).Elem().Field(i)
  23         switch d.Kind() {
  24         case reflect.String:
  25                 return d.String()
  26         case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
  27                 return strconv.FormatInt(d.Int(), 10)
  28         case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
  29                 return strconv.FormatUint(d.Uint(), 10)
  30         case reflect.Slice:
  31                 switch reflect.ValueOf(r).Elem().Type().Field(i).Tag {
  32                 case `dns:"a"`:
  33                         // TODO(miek): Hmm store this as 16 bytes
  34                         if d.Len() < net.IPv6len {
  35                                 return net.IPv4(byte(d.Index(0).Uint()),
  36                                         byte(d.Index(1).Uint()),
  37                                         byte(d.Index(2).Uint()),
  38                                         byte(d.Index(3).Uint())).String()
  39                         }
  40                         return net.IPv4(byte(d.Index(12).Uint()),
  41                                 byte(d.Index(13).Uint()),
  42                                 byte(d.Index(14).Uint()),
  43                                 byte(d.Index(15).Uint())).String()
  44                 case `dns:"aaaa"`:
  45                         return net.IP{
  46                                 byte(d.Index(0).Uint()),
  47                                 byte(d.Index(1).Uint()),
  48                                 byte(d.Index(2).Uint()),
  49                                 byte(d.Index(3).Uint()),
  50                                 byte(d.Index(4).Uint()),
  51                                 byte(d.Index(5).Uint()),
  52                                 byte(d.Index(6).Uint()),
  53                                 byte(d.Index(7).Uint()),
  54                                 byte(d.Index(8).Uint()),
  55                                 byte(d.Index(9).Uint()),
  56                                 byte(d.Index(10).Uint()),
  57                                 byte(d.Index(11).Uint()),
  58                                 byte(d.Index(12).Uint()),
  59                                 byte(d.Index(13).Uint()),
  60                                 byte(d.Index(14).Uint()),
  61                                 byte(d.Index(15).Uint()),
  62                         }.String()
  63                 case `dns:"nsec"`:
  64                         if d.Len() == 0 {
  65                                 return ""
  66                         }
  67                         s := Type(d.Index(0).Uint()).String()
  68                         for i := 1; i < d.Len(); i++ {
  69                                 s += " " + Type(d.Index(i).Uint()).String()
  70                         }
  71                         return s
  72                 default:
  73                         // if it does not have a tag its a string slice
  74                         fallthrough
  75                 case `dns:"txt"`:
  76                         if d.Len() == 0 {
  77                                 return ""
  78                         }
  79                         s := d.Index(0).String()
  80                         for i := 1; i < d.Len(); i++ {
  81                                 s += " " + d.Index(i).String()
  82                         }
  83                         return s
  84                 }
  85         }
  86         return ""
  87 }