diff options
Diffstat (limited to 'vendor/github.com/miekg/dns/privaterr.go')
-rw-r--r-- | vendor/github.com/miekg/dns/privaterr.go | 149 |
1 files changed, 149 insertions, 0 deletions
diff --git a/vendor/github.com/miekg/dns/privaterr.go b/vendor/github.com/miekg/dns/privaterr.go new file mode 100644 index 000000000..6b08e6e95 --- /dev/null +++ b/vendor/github.com/miekg/dns/privaterr.go @@ -0,0 +1,149 @@ +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() + switch rr := anyrr.(type) { + case *PrivateRR: + return rr + } + panic(fmt.Sprintf("dns: RR is not a PrivateRR, TypeToRR[%d] generator returned %T", rrtype, anyrr)) +} + +// 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() int { return r.Hdr.len() + r.Data.Len() } +func (r *PrivateRR) copy() RR { + // make new RR like this: + rr := mkPrivateRR(r.Hdr.Rrtype) + newh := r.Hdr.copyHeader() + rr.Hdr = *newh + + 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 map[string]int, compress bool) (int, error) { + off, err := r.Hdr.pack(msg, off, compression, compress) + if err != nil { + return off, err + } + headerEnd := off + n, err := r.Data.Pack(msg[off:]) + if err != nil { + return len(msg), err + } + off += n + r.Header().Rdlength = uint16(off - headerEnd) + return off, nil +} + +// 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 + + typeToUnpack[rtype] = func(h RR_Header, msg []byte, off int) (RR, int, error) { + if noRdata(h) { + return &h, off, nil + } + var err error + + rr := mkPrivateRR(h.Rrtype) + rr.Hdr = h + + off1, err := rr.Data.Unpack(msg[off:]) + off += off1 + if err != nil { + return rr, off, err + } + return rr, off, err + } + + setPrivateRR := func(h RR_Header, c chan lex, o, f string) (RR, *ParseError, string) { + rr := mkPrivateRR(h.Rrtype) + rr.Hdr = h + + 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; l.value { + case zNewline, zEOF: + break Fetch + case zString: + text = append(text, l.token) + } + } + + err := rr.Data.Parse(text) + if err != nil { + return nil, &ParseError{f, err.Error(), l}, "" + } + + return rr, nil, "" + } + + typeToparserFunc[rtype] = parserFunc{setPrivateRR, true} +} + +// PrivateHandleRemove removes defenitions required to support private RR type. +func PrivateHandleRemove(rtype uint16) { + rtypestr, ok := TypeToString[rtype] + if ok { + delete(TypeToRR, rtype) + delete(TypeToString, rtype) + delete(typeToparserFunc, rtype) + delete(StringToType, rtypestr) + delete(typeToUnpack, rtype) + } + return +} |