--- /dev/null
+package dns
+
+import (
+ "fmt"
+ "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 presentaton 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.
+ // TODO(miek): diff. signature than Pack, see edns0.go for instance.
+ Unpack([]byte) (int, error)
+ // Copy copies the Rdata.
+ 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
+}
+
+func mkPrivateRR(rrtype uint16) *PrivateRR {
+ // Panics if RR is not an instance of PrivateRR.
+ rrfunc, ok := TypeToRR[rrtype]
+ if !ok {
+ panic(fmt.Sprintf("dns: invalid operation with Private RR type %d", rrtype))
+ }
+
+ anyrr := rrfunc()
+ rr, ok := anyrr.(*PrivateRR)
+ if !ok {
+ panic(fmt.Sprintf("dns: RR is not a PrivateRR, TypeToRR[%d] generator returned %T", rrtype, anyrr))
+ }
+
+ return rr
+}
+
+// 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 := mkPrivateRR(r.Hdr.Rrtype)
+ rr.Hdr = r.Hdr
+
+ err := r.Data.Copy(rr.Data)
+ if err != nil {
+ panic("dns: got value that could not be used to copy Private rdata")
+ }
+ 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, file 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{file, err.Error(), l}
+ }
+
+ return nil
+}
+
+func (r1 *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()} }
+ 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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