mirror of
https://github.com/moby/moby.git
synced 2022-11-09 12:21:53 -05:00
117 lines
3.3 KiB
Go
117 lines
3.3 KiB
Go
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
|
|
}
|
|
|
|
// 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
|
|
|
|
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)
|
|
}
|
|
return
|
|
}
|