Create TLSA (DANE) Helper function

Sign() creates a TLSA record from a certificate

tlsa.go

@@ -1,13 +1,70 @@
 package dns
 
+import (
+	"crypto/sha256"
+	"crypto/sha512"
+	"crypto/x509"
+	"encoding/hex"
+	"io"
+	"net"
+	"strconv"
+)
+
 // TLSA support functions
 
-// Sign creates a TLSA record from a SSL certifcate.
-func (t *RR_TLSA) Sign() {
+// Sign creates a TLSA record from a SSL certificate.
+func (r *RR_TLSA) Sign(usage, selector, matchingType int, cert *x509.Certificate) error {
+	r.Hdr.Rrtype = TypeTLSA
+	r.Usage = uint8(usage)
+	r.Selector = uint8(selector)
+	r.MatchingType = uint8(matchingType)
 
+	switch r.MatchingType {
+	case 0:
+		switch s.Selector {
+		case 0:
+			r.Certificate = hex.EncodeToString(cert.Raw)
+		case 1:
+			r.Certificate = hex.EncodeToString(cert.RawSubjectPublicKeyInfo)
+		}
+	case 1:
+		h := sha256.New()
+		switch s.Selector {
+		case 0:
+			r.Certificate = hex.EncodeToString(cert.Raw)
+		case 1:
+			io.WriteString(h, string(cert.RawSubjectPublicKeyInfo))
+			r.Certificate = hex.EncodeToString(h.Sum(nil))
+		}
+	case 2:
+		h := sha512.New()
+		switch s.Selector {
+		case 0:
+			r.Certificate = hex.EncodeToString(cert.Raw)
+		case 1:
+			io.WriteString(h, string(cert.RawSubjectPublicKeyInfo))
+			r.Certificate = hex.EncodeToString(h.Sum(nil))
+		}
+	}
+	return nil
 }
 
 // Verify verifies a TLSA record against a SSL certificate.
-func (t *RR_TLSA) Verify() {
+func (r *RR_TLSA) Verify() error {
+	return nil
 
 }
+
+// Name set the ownername of the TLSA record according to the
+// rules specified in RFC 6698, Section 3.
+func (r *RR_TLSA) Name(name, service, network string) bool {
+	if !IsFqdn(name) {
+		return false
+	}
+	p, e := net.LookupPort(network, service)
+	if e != nil {
+		return false
+	}
+	r.Hdr.Name = "_" + strconv.Itoa(p) + "_" + network + "." + name
+	return true
+}