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Code Issues Releases Activity

PTR should handle "Classless in-addr.arpa delegation" RFC2317 (#149)

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* Handle IPv4 "Classless in-addr.arpa delegation" RFC2317 (partial).
* Validate PTR name when in RFC2317 "Classless in-addr.arpa delegation" domains.
* Update docs
* Set CanUsePTR for Route53 and Google CloudDNS.
* BIND: Replace "/" with "_" in filenames.
This commit is contained in:
Tom Limoncelli
2017-07-10 19:24:55 -04:00
committed by GitHub
parent 9e66402e0b
commit e563c53658
9 changed files with 203 additions and 25 deletions
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57
pkg/transform/ptr.go
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@ -1,7 +1,10 @@
package transform
import (
"fmt"
"net"
"regexp"
"strconv"
"strings"
"github.com/pkg/errors"
@ -44,10 +47,56 @@ func ipv4magic(name, domain string) (string, error) {
if err != nil {
return name, err
}
if !strings.HasSuffix(rev, "."+domain) {
err = errors.Errorf("ERROR: PTR record %v in wrong IPv4 domain (%v)", name, domain)
result := strings.TrimSuffix(rev, "."+domain)
// Are we in the right domain?
if strings.HasSuffix(rev, "."+domain) {
return result, nil
}
return strings.TrimSuffix(rev, "."+domain), err
if ipMatchesClasslessDomain(ip, domain) {
return strings.SplitN(rev, ".", 2)[0], nil
}
return "", errors.Errorf("PTR record %v in wrong IPv4 domain (%v)", name, domain)
}
var isRfc2317Format1 = regexp.MustCompile(`(\d{1,3})/(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.in-addr\.arpa$`)
// ipMatchesClasslessDomain returns true if ip is appropriate for domain.
// domain is a reverse DNS lookup zone (in-addr.arpa) as described in RFC2317.
func ipMatchesClasslessDomain(ip net.IP, domain string) bool {
// The unofficial but preferred format in RFC2317:
m := isRfc2317Format1.FindStringSubmatch(domain)
if m != nil {
// IP: Domain:
// 172.20.18.27 128/27.18.20.172.in-addr.arpa
// A B C D F M X Y Z
// The following should be true:
// A==Z, B==Y, C==X.
// If you mask ip by M, the last octet should be F.
ii := ip.To4()
a, b, c, _ := ii[0], ii[1], ii[2], ii[3]
f, m, x, y, z := atob(m[1]), atob(m[2]), atob(m[3]), atob(m[4]), atob(m[5])
masked := ip.Mask(net.CIDRMask(int(m), 32))
if a == z && b == y && c == x && masked.Equal(net.IPv4(a, b, c, f)) {
return true
}
}
// To extend this to include other formats, add them here.
return false
}
// atob converts a to a byte value or panics.
func atob(s string) byte {
if i, err := strconv.Atoi(s); err == nil {
if i < 256 {
return byte(i)
}
}
panic(fmt.Sprintf("(%v) matched \\d{1,3} but is not a byte", s))
}
func ipv6magic(name, domain string) (string, error) {
@ -63,7 +112,7 @@ func ipv6magic(name, domain string) (string, error) {
return name, err
}
if !strings.HasSuffix(rev, "."+domain) {
err = errors.Errorf("ERROR: PTR record %v in wrong IPv6 domain (%v)", name, domain)
err = errors.Errorf("PTR record %v in wrong IPv6 domain (%v)", name, domain)
}
return strings.TrimSuffix(rev, "."+domain), err
}