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Code Issues Releases Activity

Make PTR more magical (#148)

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* Initial code and tests
This commit is contained in:
Tom Limoncelli
2017-07-07 13:59:29 -04:00
committed by GitHub
parent 152892f62a
commit 582e5c2bb1
8 changed files with 214 additions and 2 deletions
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2
pkg/transform/arpa.go
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@@ -32,7 +32,7 @@ func ReverseDomainName(cidr string) (string, error) {
}
toTrim = (total - bits) / 4
} else {
return "", fmt.Errorf("Invalid mask bit size: %d", total)
return "", fmt.Errorf("Address is not IPv4 or IPv6: %v", cidr)
}
parts := strings.SplitN(base, ".", toTrim+1)

69
pkg/transform/ptr.go Normal file
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@@ -0,0 +1,69 @@
package transform
import (
"net"
"strings"
"github.com/pkg/errors"
)
func PtrNameMagic(name, domain string) (string, error) {
// Implement the PTR name magic. If the name is a properly formed
// IPv4 or IPv6 address, we replace it with the right string (i.e
// reverse it and truncate it).
// If the name is already in-addr.arpa or ipv6.arpa,
// make sure the domain matches.
if strings.HasSuffix(name, ".in-addr.arpa.") || strings.HasSuffix(name, ".ip6.arpa.") {
if strings.HasSuffix(name, "."+domain+".") {
return strings.TrimSuffix(name, "."+domain+"."), nil
} else {
return name, errors.Errorf("PTR record %v in wrong domain (%v)", name, domain)
}
}
// If the domain is .arpa, we do magic.
if strings.HasSuffix(domain, ".in-addr.arpa") {
return ipv4magic(name, domain)
} else if strings.HasSuffix(domain, ".ip6.arpa") {
return ipv6magic(name, domain)
} else {
return name, nil
}
}
func ipv4magic(name, domain string) (string, error) {
// Not a valid IPv4 address. Leave it alone.
ip := net.ParseIP(name)
if ip == nil || ip.To4() == nil || !strings.Contains(name, ".") {
return name, nil
}
// Reverse it.
rev, err := ReverseDomainName(ip.String() + "/32")
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)
}
return strings.TrimSuffix(rev, "."+domain), err
}
func ipv6magic(name, domain string) (string, error) {
// Not a valid IPv6 address. Leave it alone.
ip := net.ParseIP(name)
if ip == nil || len(ip) != 16 || !strings.Contains(name, ":") {
return name, nil
}
// Reverse it.
rev, err := ReverseDomainName(ip.String() + "/128")
if err != nil {
return name, err
}
if !strings.HasSuffix(rev, "."+domain) {
err = errors.Errorf("ERROR: PTR record %v in wrong IPv6 domain (%v)", name, domain)
}
return strings.TrimSuffix(rev, "."+domain), err
}

77
pkg/transform/ptr_test.go Normal file
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@@ -0,0 +1,77 @@
package transform
import (
"fmt"
"testing"
)
// ptrmagic(name, domain string, al int) (string, error)
func TestPtrMagic(t *testing.T) {
tests := []struct {
name string
domain string
output string
fail bool
}{
// Magic IPv4:
{"1.2.3.4", "3.2.1.in-addr.arpa", "4", false},
{"1.2.3.4", "2.1.in-addr.arpa", "4.3", false},
{"1.2.3.4", "1.in-addr.arpa", "4.3.2", false},
// No magic IPv4:
{"1", "2.3.4.in-addr.arpa", "1", false},
{"1.2", "3.4.in-addr.arpa", "1.2", false},
{"1.2.3", "4.in-addr.arpa", "1.2.3", false},
{"1.2.3.4", "in-addr.arpa", "1.2.3.4", false}, // Not supported, but it works.
// Magic IPv6:
{"1", "0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.8.b.d.0.1.0.0.2.ip6.arpa", "1", false},
{"1.0", "0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.8.b.d.0.1.0.0.2.ip6.arpa", "1.0", false},
{"1.0.0", "0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.8.b.d.0.1.0.0.2.ip6.arpa", "1.0.0", false},
{"1.0.0.0", "0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.8.b.d.0.1.0.0.2.ip6.arpa", "1.0.0.0", false},
{"1.0.0.0.0", "0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.8.b.d.0.1.0.0.2.ip6.arpa", "1.0.0.0.0", false},
{"1.0.0.0.0.0", "0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.8.b.d.0.1.0.0.2.ip6.arpa", "1.0.0.0.0.0", false},
{"1.0.0.0.0.0.0", "0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.8.b.d.0.1.0.0.2.ip6.arpa", "1.0.0.0.0.0.0", false},
{"1.0.0.0.0.0.0.0", "0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.8.b.d.0.1.0.0.2.ip6.arpa", "1.0.0.0.0.0.0.0", false},
{"1.0.0.0.0.0.0.0.0", "0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.8.b.d.0.1.0.0.2.ip6.arpa", "1.0.0.0.0.0.0.0.0", false},
{"1.0.0.0.0.0.0.0.0.0", "0.0.0.0.0.0.0.0.0.0.0.0.0.0.8.b.d.0.1.0.0.2.ip6.arpa", "1.0.0.0.0.0.0.0.0.0", false},
{"1.0.0.0.0.0.0.0.0.0.0", "0.0.0.0.0.0.0.0.0.0.0.0.0.8.b.d.0.1.0.0.2.ip6.arpa", "1.0.0.0.0.0.0.0.0.0.0", false},
{"1.0.0.0.0.0.0.0.0.0.0.0", "0.0.0.0.0.0.0.0.0.0.0.0.8.b.d.0.1.0.0.2.ip6.arpa", "1.0.0.0.0.0.0.0.0.0.0.0", false},
{"1.0.0.0.0.0.0.0.0.0.0.0.0", "0.0.0.0.0.0.0.0.0.0.0.8.b.d.0.1.0.0.2.ip6.arpa", "1.0.0.0.0.0.0.0.0.0.0.0.0", false},
{"1.0.0.0.0.0.0.0.0.0.0.0.0.0", "0.0.0.0.0.0.0.0.0.0.8.b.d.0.1.0.0.2.ip6.arpa", "1.0.0.0.0.0.0.0.0.0.0.0.0.0", false},
// If it doesn't end in .arpa, the magic is disabled:
{"1.2.3.4", "example.com", "1.2.3.4", false},
{"1", "example.com", "1", false},
{"1.0.0.0", "example.com", "1.0.0.0", false},
{"1.0.0.0.0.0.0.0", "example.com", "1.0.0.0.0.0.0.0", false},
// User manually reversed addresses:
{"1.1.1.1.in-addr.arpa.", "1.1.in-addr.arpa", "1.1", false},
{"1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.8.b.d.0.1.0.0.2.ip6.arpa.",
"0.2.ip6.arpa", "1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.8.b.d.0.1.0", false},
// Error cases:
{"1.1.1.1.in-addr.arpa.", "2.2.in-addr.arpa", "", true},
{"1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.8.b.d.0.1.0.0.2.ip6.arpa.", "9.9.ip6.arpa", "", true},
{"3.3.3.3", "4.4.in-addr.arpa", "", true},
{"2001:db8::1", "9.9.ip6.arpa", "", true},
// These should be errors but we don't check for them at this time:
//{"blurg", "3.4.in-addr.arpa", "blurg", true},
//{"1", "3.4.in-addr.arpa", "1", true},
}
for _, tst := range tests {
t.Run(fmt.Sprintf("%s %s", tst.name, tst.domain), func(t *testing.T) {
o, errs := PtrNameMagic(tst.name, tst.domain)
if errs != nil && !tst.fail {
t.Errorf("Got error but expected none (%v)", errs)
} else if errs == nil && tst.fail {
t.Errorf("Expected error but got none (%v)", o)
} else if errs == nil && o != tst.output {
t.Errorf("Got (%v) expected (%v)", o, tst.output)
}
})
}
}