tsig.go

package dns

import (
	"crypto/hmac"
	"crypto/md5"
	"crypto/sha1"
	"crypto/sha256"
	"crypto/sha512"
	"encoding/hex"
	"hash"
	"io"
	"strconv"
	"strings"
	"time"
)

// HMAC hashing codes. These are transmitted as domain names.
const (
	HmacMD5    = "hmac-md5.sig-alg.reg.int."
	HmacSHA1   = "hmac-sha1."
	HmacSHA256 = "hmac-sha256."
	HmacSHA512 = "hmac-sha512."
)

// TSIG is the RR the holds the transaction signature of a message.
// See RFC 2845 and RFC 4635.
type TSIG struct {
	Hdr        RR_Header
	Algorithm  string `dns:"domain-name"`
	TimeSigned uint64 `dns:"uint48"`
	Fudge      uint16
	MACSize    uint16
	MAC        string `dns:"size-hex"`
	OrigId     uint16
	Error      uint16
	OtherLen   uint16
	OtherData  string `dns:"size-hex"`
}

func (rr *TSIG) Header() *RR_Header {
	return &rr.Hdr
}

// TSIG has no official presentation format, but this will suffice.

func (rr *TSIG) String() string {
	s := "\n;; TSIG PSEUDOSECTION:\n"
	s += rr.Hdr.String() +
		" " + rr.Algorithm +
		" " + tsigTimeToString(rr.TimeSigned) +
		" " + strconv.Itoa(int(rr.Fudge)) +
		" " + strconv.Itoa(int(rr.MACSize)) +
		" " + strings.ToUpper(rr.MAC) +
		" " + strconv.Itoa(int(rr.OrigId)) +
		" " + strconv.Itoa(int(rr.Error)) + // BIND prints NOERROR
		" " + strconv.Itoa(int(rr.OtherLen)) +
		" " + rr.OtherData
	return s
}

func (rr *TSIG) len() int {
	return rr.Hdr.len() + len(rr.Algorithm) + 1 + 6 +
		4 + len(rr.MAC)/2 + 1 + 6 + len(rr.OtherData)/2 + 1
}

func (rr *TSIG) copy() RR {
	return &TSIG{*rr.Hdr.copyHeader(), rr.Algorithm, rr.TimeSigned, rr.Fudge, rr.MACSize, rr.MAC, rr.OrigId, rr.Error, rr.OtherLen, rr.OtherData}
}

// The following values must be put in wireformat, so that the MAC can be calculated.