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- package dns
-
- import "strings"
-
- // PrivateRdata is an interface used for implementing "Private Use" RR types, see
- // RFC 6895. This allows one to experiment with new RR types, without requesting an
- // official type code. Also see dns.PrivateHandle and dns.PrivateHandleRemove.
- type PrivateRdata interface {
- // String returns the text presentation of the Rdata of the Private RR.
- String() string
- // Parse parses the Rdata of the private RR.
- Parse([]string) error
- // Pack is used when packing a private RR into a buffer.
- Pack([]byte) (int, error)
- // Unpack is used when unpacking a private RR from a buffer.
- Unpack([]byte) (int, error)
- // Copy copies the Rdata into the PrivateRdata argument.
- Copy(PrivateRdata) error
- // Len returns the length in octets of the Rdata.
- Len() int
- }
-
- // PrivateRR represents an RR that uses a PrivateRdata user-defined type.
- // It mocks normal RRs and implements dns.RR interface.
- type PrivateRR struct {
- Hdr RR_Header
- Data PrivateRdata
-
- generator func() PrivateRdata // for copy
- }
-
- // Header return the RR header of r.
- func (r *PrivateRR) Header() *RR_Header { return &r.Hdr }
-
- func (r *PrivateRR) String() string { return r.Hdr.String() + r.Data.String() }
-
- // Private len and copy parts to satisfy RR interface.
- func (r *PrivateRR) len(off int, compression map[string]struct{}) int {
- l := r.Hdr.len(off, compression)
- l += r.Data.Len()
- return l
- }
-
- func (r *PrivateRR) copy() RR {
- // make new RR like this:
- rr := &PrivateRR{r.Hdr, r.generator(), r.generator}
-
- if err := r.Data.Copy(rr.Data); err != nil {
- panic("dns: got value that could not be used to copy Private rdata: " + err.Error())
- }
-
- return rr
- }
-
- func (r *PrivateRR) pack(msg []byte, off int, compression compressionMap, compress bool) (int, error) {
- n, err := r.Data.Pack(msg[off:])
- if err != nil {
- return len(msg), err
- }
- off += n
- return off, nil
- }
-
- func (r *PrivateRR) unpack(msg []byte, off int) (int, error) {
- off1, err := r.Data.Unpack(msg[off:])
- off += off1
- return off, err
- }
-
- func (r *PrivateRR) parse(c *zlexer, origin string) *ParseError {
- var l lex
- text := make([]string, 0, 2) // could be 0..N elements, median is probably 1
- Fetch:
- for {
- // TODO(miek): we could also be returning _QUOTE, this might or might not
- // be an issue (basically parsing TXT becomes hard)
- switch l, _ = c.Next(); l.value {
- case zNewline, zEOF:
- break Fetch
- case zString:
- text = append(text, l.token)
- }
- }
-
- err := r.Data.Parse(text)
- if err != nil {
- return &ParseError{"", err.Error(), l}
- }
-
- return nil
- }
-
- func (r *PrivateRR) isDuplicate(r2 RR) bool { return false }
-
- // PrivateHandle registers a private resource record type. It requires
- // string and numeric representation of private RR type and generator function as argument.
- func PrivateHandle(rtypestr string, rtype uint16, generator func() PrivateRdata) {
- rtypestr = strings.ToUpper(rtypestr)
-
- TypeToRR[rtype] = func() RR { return &PrivateRR{RR_Header{}, generator(), generator} }
- TypeToString[rtype] = rtypestr
- StringToType[rtypestr] = rtype
- }
-
- // PrivateHandleRemove removes definitions required to support private RR type.
- func PrivateHandleRemove(rtype uint16) {
- rtypestr, ok := TypeToString[rtype]
- if ok {
- delete(TypeToRR, rtype)
- delete(TypeToString, rtype)
- delete(StringToType, rtypestr)
- }
- }
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