package dns
import (
"fmt"
"regexp"
"strconv"
"strings"
"testing"
)
const maxPrintableLabel = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789x"
var (
longDomain = maxPrintableLabel[:53] + strings.TrimSuffix(
strings.Join([]string{".", ".", ".", ".", "."}, maxPrintableLabel[:49]), ".")
reChar = regexp.MustCompile(`.`)
i = -1
maxUnprintableLabel = reChar.ReplaceAllStringFunc(maxPrintableLabel, func(ch string) string {
if i++; i >= 32 {
i = 0
}
return fmt.Sprintf("\\%03d", i)
})
// These are the longest possible domain names in presentation format.
longestDomain = maxPrintableLabel[:61] + strings.Join([]string{".", ".", ".", "."}, maxPrintableLabel)
longestUnprintableDomain = maxUnprintableLabel[:61*4] + strings.Join([]string{".", ".", ".", "."}, maxUnprintableLabel)
)
func TestPackNoSideEffect(t *testing.T) {
m := new(Msg)
m.SetQuestion(Fqdn("example.com."), TypeNS)
a := new(Msg)
o := &OPT{
Hdr: RR_Header{
Name: ".",
Rrtype: TypeOPT,
},
}
o.SetUDPSize(DefaultMsgSize)
a.Extra = append(a.Extra, o)
a.SetRcode(m, RcodeBadVers)
a.Pack()
if a.Rcode != RcodeBadVers {
t.Errorf("after pack: Rcode is expected to be BADVERS")
}
}
func TestPackExtendedBadCookie(t *testing.T) {
m := new(Msg)
m.SetQuestion(Fqdn("example.com."), TypeNS)
a := new(Msg)
a.SetReply(m)
o := &OPT{
Hdr: RR_Header{
Name: ".",
Rrtype: TypeOPT,
},
}
o.SetUDPSize(DefaultMsgSize)
a.Extra = append(a.Extra, o)
a.SetRcode(m, RcodeBadCookie)
edns0 := a.IsEdns0()
if edns0 == nil {
t.Fatal("Expected OPT RR")
}
// SetExtendedRcode is only called as part of `Pack()`, hence at this stage,
// the OPT RR is not set yet.
if edns0.ExtendedRcode() == RcodeBadCookie&0xFFFFFFF0 {
t.Errorf("ExtendedRcode is expected to not be BADCOOKIE before Pack")
}
a.Pack()
edns0 = a.IsEdns0()
if edns0 == nil {
t.Fatal("Expected OPT RR")
}
if edns0.ExtendedRcode() != RcodeBadCookie&0xFFFFFFF0 {
t.Errorf("ExtendedRcode is expected to be BADCOOKIE after Pack")
}
}
func TestUnPackExtendedRcode(t *testing.T) {
m := new(Msg)
m.SetQuestion(Fqdn("example.com."), TypeNS)
a := new(Msg)
a.SetReply(m)
o := &OPT{
Hdr: RR_Header{
Name: ".",
Rrtype: TypeOPT,
},
}
o.SetUDPSize(DefaultMsgSize)
a.Extra = append(a.Extra, o)
a.SetRcode(m, RcodeBadCookie)
packed, err := a.Pack()
if err != nil {
t.Fatalf("Could not unpack %v", a)
}
unpacked := new(Msg)
if err := unpacked.Unpack(packed); err != nil {
t.Fatalf("Failed to unpack message")
}
if unpacked.Rcode != RcodeBadCookie {
t.Fatalf("Rcode should be matching RcodeBadCookie (%d), got (%d)", RcodeBadCookie, unpacked.Rcode)
}
}
func TestUnpackDomainName(t *testing.T) {
var cases = []struct {
label string
input string
expectedOutput string
expectedError string
}{
{"empty domain",
"\x00",
".",
""},
{"long label",
"?" + maxPrintableLabel + "\x00",
maxPrintableLabel + ".",
""},
{"unprintable label",
"?" + regexp.MustCompile(`\\[0-9]+`).ReplaceAllStringFunc(maxUnprintableLabel,
func(escape string) string {
n, _ := strconv.ParseInt(escape[1:], 10, 8)
return string(rune(n))
}) + "\x00",
maxUnprintableLabel + ".",
""},
{"long domain",
"5" + strings.Replace(longDomain, ".", "1", -1) + "\x00",
longDomain + ".",
""},
{"compression pointer",
// an unrealistic but functional test referencing an offset _inside_ a label
"\x03foo" + "\x05\x03com\x00" + "\x07example" + "\xC0\x05",
"foo.\\003com\\000.example.com.",
""},
{"too long domain",
"6" + "x" + strings.Replace(longDomain, ".", "1", -1) + "\x00",
"",
ErrLongDomain.Error()},
{"too long by pointer",
// a matryoshka doll name to get over 255 octets after expansion via internal pointers
string([]byte{
// 11 length values, first to last
40, 37, 34, 31, 28, 25, 22, 19, 16, 13, 0,
// 12 filler values
120, 120, 120, 120, 120, 120, 120, 120, 120, 120, 120, 120,
// 10 pointers, last to first
192, 10, 192, 9, 192, 8, 192, 7, 192, 6, 192, 5, 192, 4, 192, 3, 192, 2, 192, 1,
}),
"",
ErrLongDomain.Error()},
{"long by pointer",
// a matryoshka doll name _not_ exceeding 255 octets after expansion
string([]byte{
// 11 length values, first to last
37, 34, 31, 28, 25, 22, 19, 16, 13, 10, 0,
// 9 filler values
120, 120, 120, 120, 120, 120, 120, 120, 120,
// 10 pointers, last to first
192, 10, 192, 9, 192, 8, 192, 7, 192, 6, 192, 5, 192, 4, 192, 3, 192, 2, 192, 1,
}),
"" +
(`\"\031\028\025\022\019\016\013\010\000xxxxxxxxx` +
`\192\010\192\009\192\008\192\007\192\006\192\005\192\004\192\003\192\002.`) +
(`\031\028\025\022\019\016\013\010\000xxxxxxxxx` +
`\192\010\192\009\192\008\192\007\192\006\192\005\192\004\192\003.`) +
(`\028\025\022\019\016\013\010\000xxxxxxxxx` +
`\192\010\192\009\192\008\192\007\192\006\192\005\192\004.`) +
(`\025\022\019\016\013\010\000xxxxxxxxx` +
`\192\010\192\009\192\008\192\007\192\006\192\005.`) +
`\022\019\016\013\010\000xxxxxxxxx\192\010\192\009\192\008\192\007\192\006.` +
`\019\016\013\010\000xxxxxxxxx\192\010\192\009\192\008\192\007.` +
`\016\013\010\000xxxxxxxxx\192\010\192\009\192\008.` +
`\013\010\000xxxxxxxxx\192\010\192\009.` +
`\010\000xxxxxxxxx\192\010.` +
`\000xxxxxxxxx.`,
""},
{"truncated name", "\x07example\x03", "", "dns: buffer size too small"},
{"non-absolute name", "\x07example\x03com", "", "dns: buffer size too small"},
{"compression pointer cycle (too many)", "\xC0\x00", "", "dns: too many compression pointers"},
{"compression pointer cycle (too long)",
"\x03foo" + "\x03bar" + "\x07example" + "\xC0\x04",
"",
ErrLongDomain.Error()},
{"forward compression pointer", "\x02\xC0\xFF\xC0\x01", "", ErrBuf.Error()},
{"reserved compression pointer 0b10", "\x07example\x80", "", "dns: bad rdata"},
{"reserved compression pointer 0b01", "\x07example\x40", "", "dns: bad rdata"},
}
for _, test := range cases {
output, idx, err := UnpackDomainName([]byte(test.input), 0)
if test.expectedOutput != "" && output != test.expectedOutput {
t.Errorf("%s: expected %s, got %s", test.label, test.expectedOutput, output)
}
if test.expectedError == "" && err != nil {
t.Errorf("%s: expected no error, got %d %v", test.label, idx, err)
} else if test.expectedError != "" && (err == nil || err.Error() != test.expectedError) {
t.Errorf("%s: expected error %s, got %d %v", test.label, test.expectedError, idx, err)
}
}
}
func TestPackDomainNameCompressionMap(t *testing.T) {
expected := map[string]struct{}{
`www\.this.is.\131an.example.org.`: {},
`is.\131an.example.org.`: {},
`\131an.example.org.`: {},
`example.org.`: {},
`org.`: {},
}
msg := make([]byte, 256)
for _, compress := range []bool{true, false} {
compression := make(map[string]int)
_, err := PackDomainName(`www\.this.is.\131an.example.org.`, msg, 0, compression, compress)
if err != nil {
t.Fatalf("PackDomainName failed: %v", err)
}
if !compressionMapsEqual(expected, compression) {
t.Errorf("expected compression maps to be equal\n%s", compressionMapsDifference(expected, compression))
}
}
}
func TestPackDomainNameNSECTypeBitmap(t *testing.T) {
ownername := "some-very-long-ownername.com."
msg := &Msg{
Compress: true,
Answer: []RR{
&NS{
Hdr: RR_Header{
Name: ownername,
Rrtype: TypeNS,
Class: ClassINET,
},
Ns: "ns1.server.com.",
},
&NSEC{
Hdr: RR_Header{
Name: ownername,
Rrtype: TypeNSEC,
Class: ClassINET,
},
NextDomain: "a.com.",
TypeBitMap: []uint16{TypeNS, TypeNSEC},
},
},
}
// Pack msg and then unpack into msg2
buf, err := msg.Pack()
if err != nil {
t.Fatalf("msg.Pack failed: %v", err)
}
var msg2 Msg
if err := msg2.Unpack(buf); err != nil {
t.Fatalf("msg2.Unpack failed: %v", err)
}
if !IsDuplicate(msg.Answer[1], msg2.Answer[1]) {
t.Error("message differs after packing and unpacking")
// Print NSEC RR for both cases
t.Logf("expected: %v", msg.Answer[1])
t.Logf("got: %v", msg2.Answer[1])
}
}
func TestPackUnpackManyCompressionPointers(t *testing.T) {
m := new(Msg)
m.Compress = true
m.SetQuestion("example.org.", TypeNS)
for domain := "a."; len(domain) < maxDomainNameWireOctets; domain += "a." {
m.Answer = append(m.Answer, &NS{Hdr: RR_Header{Name: domain, Rrtype: TypeNS, Class: ClassINET}, Ns: "example.org."})
b, err := m.Pack()
if err != nil {
t.Fatalf("Pack failed for %q and %d records with: %v", domain, len(m.Answer), err)
}
var m2 Msg
if err := m2.Unpack(b); err != nil {
t.Fatalf("Unpack failed for %q and %d records with: %v", domain, len(m.Answer), err)
}
}
}
func TestLenDynamicA(t *testing.T) {
for _, rr := range []RR{
testRR("example.org. A"),
testRR("example.org. AAAA"),
testRR("example.org. L32"),
} {
msg := make([]byte, Len(rr))
off, err := PackRR(rr, msg, 0, nil, false)
if err != nil {
t.Fatalf("PackRR failed for %T: %v", rr, err)
}
if off != len(msg) {
t.Errorf("Len(rr) wrong for %T: Len(rr) = %d, PackRR(rr) = %d", rr, len(msg), off)
}
}
}