lib/dns: refactoring message question

Previously the type for message question section SectionQuestion.

This changes, rename the type to MessageQuestion.

15 files changed, 336 insertions, 193 deletions

diff --git a/lib/dns/answer_test.go b/lib/dns/answer_test.go
index 1c083233..10651123 100644
--- a/lib/dns/answer_test.go
+++ b/lib/dns/answer_test.go
@@ -19,7 +19,7 @@ func TestNewAnswer(t *testing.T) {
 		Header: MessageHeader{
 			ID: 1,
 		},
-		Question: SectionQuestion{
+		Question: MessageQuestion{
 			Name:  "test",
 			Type:  1,
 			Class: 1,
@@ -125,7 +125,7 @@ func TestAnswerGet(t *testing.T) {
 			QDCount: 1,
 			ANCount: 1,
 		},
-		Question: SectionQuestion{
+		Question: MessageQuestion{
 			Name:  "kilabit.info",
 			Type:  RecordTypeA,
 			Class: RecordClassIN,
@@ -184,7 +184,7 @@ func TestAnswerGet(t *testing.T) {
 		test.Assert(t, "AccessedAt", an.AccessedAt >= at, true)
 		got := &Message{
 			Header:   MessageHeader{},
-			Question: SectionQuestion{},
+			Question: MessageQuestion{},
 			packet:   gotPacket,
 		}
 		err := got.Unpack()
diff --git a/lib/dns/answers_test.go b/lib/dns/answers_test.go
index f3f758c3..503141b5 100644
--- a/lib/dns/answers_test.go
+++ b/lib/dns/answers_test.go
@@ -47,7 +47,7 @@ func TestNewAnswers(t *testing.T) {
 
 func TestAnswersGet(t *testing.T) {
 	msg := &Message{
-		Question: SectionQuestion{
+		Question: MessageQuestion{
 			Name:  "test",
 			Type:  1,
 			Class: 1,
@@ -98,7 +98,7 @@ func TestAnswersGet(t *testing.T) {
 
 func TestAnswersRemove(t *testing.T) {
 	msg := &Message{
-		Question: SectionQuestion{
+		Question: MessageQuestion{
 			Name:  "test",
 			Type:  1,
 			Class: 1,
diff --git a/lib/dns/doh_client_test.go b/lib/dns/doh_client_test.go
index 3309a1ff..d1da8dfc 100644
--- a/lib/dns/doh_client_test.go
+++ b/lib/dns/doh_client_test.go
@@ -37,7 +37,7 @@ func TestDoHClient_Lookup(t *testing.T) {
 				QDCount: 1,
 				ANCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "kilabit.info",
 				Type:  RecordTypeA,
 				Class: RecordClassIN,
@@ -65,7 +65,7 @@ func TestDoHClient_Lookup(t *testing.T) {
 				QDCount: 1,
 				ANCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "kilabit.info",
 				Type:  RecordTypeSOA,
 				Class: RecordClassIN,
@@ -100,7 +100,7 @@ func TestDoHClient_Lookup(t *testing.T) {
 				QDCount: 1,
 				ANCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "kilabit.info",
 				Type:  RecordTypeTXT,
 				Class: RecordClassIN,
@@ -127,7 +127,7 @@ func TestDoHClient_Lookup(t *testing.T) {
 				RCode:   RCodeErrServer,
 				QDCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "kilabit.info",
 				Type:  RecordTypeAAAA,
 				Class: RecordClassIN,
@@ -182,7 +182,7 @@ func TestDoHClient_Post(t *testing.T) {
 				QDCount: 1,
 				ANCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "kilabit.info",
 				Type:  RecordTypeA,
 				Class: RecordClassIN,
@@ -210,7 +210,7 @@ func TestDoHClient_Post(t *testing.T) {
 				QDCount: 1,
 				ANCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "kilabit.info",
 				Type:  RecordTypeSOA,
 				Class: RecordClassIN,
@@ -245,7 +245,7 @@ func TestDoHClient_Post(t *testing.T) {
 				QDCount: 1,
 				ANCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "kilabit.info",
 				Type:  RecordTypeTXT,
 				Class: RecordClassIN,
@@ -272,7 +272,7 @@ func TestDoHClient_Post(t *testing.T) {
 				RCode:   RCodeErrServer,
 				QDCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "kilabit.info",
 				Type:  RecordTypeAAAA,
 				Class: RecordClassIN,
diff --git a/lib/dns/dot_client_test.go b/lib/dns/dot_client_test.go
index ee7c55fb..17afca17 100644
--- a/lib/dns/dot_client_test.go
+++ b/lib/dns/dot_client_test.go
@@ -35,7 +35,7 @@ func TestDoTClient_Lookup(t *testing.T) {
 				QDCount: 1,
 				ANCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "kilabit.info",
 				Type:  RecordTypeA,
 				Class: RecordClassIN,
@@ -63,7 +63,7 @@ func TestDoTClient_Lookup(t *testing.T) {
 				QDCount: 1,
 				ANCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "kilabit.info",
 				Type:  RecordTypeSOA,
 				Class: RecordClassIN,
@@ -98,7 +98,7 @@ func TestDoTClient_Lookup(t *testing.T) {
 				QDCount: 1,
 				ANCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "kilabit.info",
 				Type:  RecordTypeTXT,
 				Class: RecordClassIN,
diff --git a/lib/dns/message.go b/lib/dns/message.go
index 0fa4532a..875736d8 100644
--- a/lib/dns/message.go
+++ b/lib/dns/message.go
@@ -52,13 +52,13 @@ import (
 //
 type Message struct {
 	Header     MessageHeader
-	Question   SectionQuestion
+	Question   MessageQuestion
 	Answer     []ResourceRecord
 	Authority  []ResourceRecord
 	Additional []ResourceRecord
 
-	// Slice that hold the result of packing the message or original
-	// message from unpacking.
+	// The raw message as result of packing or original packet from
+	// unpacking.
 	packet []byte
 
 	// offset of curret packet when packing, equal to len(packet).
@@ -79,7 +79,7 @@ func NewMessage() *Message {
 			IsRD:    true,
 			QDCount: 1,
 		},
-		Question: SectionQuestion{
+		Question: MessageQuestion{
 			Type:  RecordTypeA,
 			Class: RecordClassIN,
 		},
@@ -125,7 +125,7 @@ func NewMessageAddress(hname []byte, addresses [][]byte) (msg *Message) {
 			QDCount: 1,
 			ANCount: 1,
 		},
-		Question: SectionQuestion{
+		Question: MessageQuestion{
 			Name:  string(hname),
 			Type:  rtype,
 			Class: RecordClassIN,
@@ -169,7 +169,7 @@ func NewMessageFromRR(rr *ResourceRecord) (msg *Message, err error) {
 			QDCount: 1,
 			ANCount: 1,
 		},
-		Question: SectionQuestion{
+		Question: MessageQuestion{
 			Name:  rr.Name,
 			Type:  rr.Type,
 			Class: rr.Class,
diff --git a/lib/dns/message_question.go b/lib/dns/message_question.go
new file mode 100644
index 00000000..5e398d8d
--- /dev/null
+++ b/lib/dns/message_question.go
@@ -0,0 +1,99 @@
+// Copyright 2018, Shulhan <ms@kilabit.info>. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package dns
+
+import (
+	"fmt"
+	"strings"
+
+	libbytes "github.com/shuLhan/share/lib/bytes"
+)
+
+//
+// MessageQuestion contains the "question" in most queries.
+//
+type MessageQuestion struct {
+	// The domain name to be queried.
+	Name string
+
+	// The Type of query.
+	Type RecordType
+
+	// The Class of the query.
+	Class RecordClass
+}
+
+//
+// Reset the message question field to it's default values for query.
+//
+func (qst *MessageQuestion) Reset() {
+	qst.Name = ""
+	qst.Type = RecordTypeA
+	qst.Class = RecordClassIN
+}
+
+func (qst *MessageQuestion) String() string {
+	return fmt.Sprintf("{Name:%s Type:%s}", qst.Name, RecordTypeNames[qst.Type])
+}
+
+//
+// size return the section question size, length of name + 2 (1 octet for
+// beginning size plus 1 octet for end of label) + 2 octets of
+// rtype + 2 octets of rclass
+//
+func (qst *MessageQuestion) size() int {
+	return len(qst.Name) + 6
+}
+
+//
+// unpack the DNS question section from packet.
+//
+func (qst *MessageQuestion) unpack(packet []byte) (err error) {
+	if len(packet) == 0 {
+		return nil
+	}
+
+	var (
+		logp  = "MessageQuestion.unpack"
+		sb    strings.Builder
+		x     int
+		y     int
+		count int
+	)
+
+	for {
+		count = int(packet[x])
+		if count == 0 {
+			x++
+			break
+		}
+		if x+count+1 >= len(packet) {
+			return fmt.Errorf("%s: label length overflow at index %d", logp, x)
+		}
+		if sb.Len() > 0 {
+			sb.WriteByte('.')
+		}
+		for y = 0; y < count; y++ {
+			x++
+			if packet[x] >= 'A' && packet[x] <= 'Z' {
+				sb.WriteByte(packet[x] + 32)
+			} else {
+				sb.WriteByte(packet[x])
+			}
+		}
+		x++
+	}
+
+	if x+4 > len(packet) {
+		return fmt.Errorf("%s: packet too small, missing type and/or class", logp)
+	}
+
+	qst.Name = sb.String()
+	qst.Type = RecordType(libbytes.ReadUint16(packet, uint(x)))
+	x += 2
+	qst.Class = RecordClass(libbytes.ReadUint16(packet, uint(x)))
+
+	return nil
+}
diff --git a/lib/dns/message_question_bench_test.go b/lib/dns/message_question_bench_test.go
new file mode 100644
index 00000000..3ae8f44c
--- /dev/null
+++ b/lib/dns/message_question_bench_test.go
@@ -0,0 +1,56 @@
+// Copyright 2021, Shulhan <ms@kilabit.info>. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package dns
+
+import "testing"
+
+/**
+== 2021-11-15
+
+goos: linux
+goarch: amd64
+pkg: github.com/shuLhan/share/lib/dns
+cpu: 11th Gen Intel(R) Core(TM) i5-1135G7 @ 2.40GHz
+BenchmarkMessageQuestion_String-8        7138899               168.3 ns/op            56 B/op          3 allocs/op
+**/
+func BenchmarkMessageQuestion_String(b *testing.B) {
+	mq := MessageQuestion{
+		Name: "test",
+		Type: RecordTypeA,
+	}
+	for x := 0; x < b.N; x++ {
+		_ = mq.String()
+	}
+}
+
+/**
+== 2021-11-14
+
+goos: linux
+goarch: amd64
+pkg: github.com/shuLhan/share/lib/dns
+cpu: 11th Gen Intel(R) Core(TM) i5-1135G7 @ 2.40GHz
+BenchmarkMessageQuestion_unpack-8       35717178                35.78 ns/op            8 B/op          1 allocs/op
+**/
+func BenchmarkMessageQuestion_unpack(b *testing.B) {
+	var (
+		packet = []byte{
+			0x01, 'a',
+			0x01, 'B',
+			0x01, 'c',
+			0x00,
+			0x00, 0x01,
+			0x00, 0x01,
+		}
+		err error
+	)
+	mq := MessageQuestion{}
+	for x := 0; x < b.N; x++ {
+		err = mq.unpack(packet)
+		if err != nil {
+			b.Fatal(err)
+		}
+	}
+}
diff --git a/lib/dns/message_question_test.go b/lib/dns/message_question_test.go
new file mode 100644
index 00000000..3bde97a3
--- /dev/null
+++ b/lib/dns/message_question_test.go
@@ -0,0 +1,105 @@
+// Copyright 2021, Shulhan <ms@kilabit.info>. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package dns
+
+import (
+	"testing"
+
+	"github.com/shuLhan/share/lib/test"
+)
+
+func TestMessageQuestion_String(t *testing.T) {
+	cases := []struct {
+		desc string
+		mq   MessageQuestion
+		exp  string
+	}{{
+		desc: "With unknown type",
+		mq: MessageQuestion{
+			Name: "test",
+			Type: RecordType(17),
+		},
+		exp: `{Name:test Type:}`,
+	}, {
+		desc: "With known type",
+		mq: MessageQuestion{
+			Name: "test",
+			Type: RecordTypeA,
+		},
+		exp: `{Name:test Type:A}`,
+	}}
+
+	for _, c := range cases {
+		test.Assert(t, c.desc, c.exp, c.mq.String())
+	}
+}
+
+func TestMessageQuestion_unpack(t *testing.T) {
+	cases := []struct {
+		desc   string
+		mq     MessageQuestion
+		packet []byte
+		expErr string
+	}{{
+		desc: "With empty packet",
+		mq:   MessageQuestion{},
+	}, {
+		desc: "With zero label",
+		packet: []byte{
+			0x00,
+			0x00, 0x01,
+			0x00, 0x01,
+		},
+		mq: MessageQuestion{
+			Name:  "",
+			Type:  RecordTypeA,
+			Class: RecordClassIN,
+		},
+	}, {
+		desc: "With invalid label length",
+		packet: []byte{
+			0x06, 'a',
+			0x0,
+			0x00, 0x01,
+			0x00, 0x01,
+		},
+		expErr: "MessageQuestion.unpack: label length overflow at index 0",
+	}, {
+		desc: "With packet too small",
+		packet: []byte{
+			0x01, 'a',
+			0x00,
+			0x00, 0x01,
+			0x00,
+		},
+		expErr: "MessageQuestion.unpack: packet too small, missing type and/or class",
+	}, {
+		desc: "With label",
+		packet: []byte{
+			0x01, 'a',
+			0x01, 'B',
+			0x01, 'c',
+			0x00,
+			0x00, 0x01,
+			0x00, 0x01,
+		},
+		mq: MessageQuestion{
+			Name:  "a.b.c",
+			Type:  RecordTypeA,
+			Class: RecordClassIN,
+		},
+	}}
+
+	for _, c := range cases {
+		t.Log(c.desc)
+		gotMQ := MessageQuestion{}
+		err := gotMQ.unpack(c.packet)
+		if err != nil {
+			test.Assert(t, c.desc, c.expErr, err.Error())
+			continue
+		}
+		test.Assert(t, c.desc, c.mq, gotMQ)
+	}
+}
diff --git a/lib/dns/message_test.go b/lib/dns/message_test.go
index 3b57d435..0a2ce360 100644
--- a/lib/dns/message_test.go
+++ b/lib/dns/message_test.go
@@ -84,7 +84,7 @@ func TestMessagePackQuestion(t *testing.T) {
 	}{{
 		desc: "Empty name",
 		msg: &Message{
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Type:  RecordTypeA,
 				Class: RecordClassIN,
 			},
@@ -96,7 +96,7 @@ func TestMessagePackQuestion(t *testing.T) {
 	}, {
 		desc: "Single domain name",
 		msg: &Message{
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "kilaBit",
 				Type:  RecordTypeA,
 				Class: RecordClassIN,
@@ -110,7 +110,7 @@ func TestMessagePackQuestion(t *testing.T) {
 	}, {
 		desc: "Two domain names",
 		msg: &Message{
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "kilabit.info",
 				Type:  RecordTypeA,
 				Class: RecordClassIN,
@@ -126,7 +126,7 @@ func TestMessagePackQuestion(t *testing.T) {
 	}, {
 		desc: "Three domain names",
 		msg: &Message{
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "MAIL.KILABIT.INFO",
 				Type:  RecordTypeA,
 				Class: RecordClassIN,
@@ -164,7 +164,7 @@ func TestMessagePack(t *testing.T) {
 				IsQuery: true,
 				QDCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "kilabit.INFO",
 				Type:  RecordTypeA,
 				Class: RecordClassIN,
@@ -197,7 +197,7 @@ func TestMessagePack(t *testing.T) {
 				ANCount: 1,
 				ARCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "kilabit.info",
 				Type:  RecordTypeA,
 				Class: RecordClassIN,
@@ -286,7 +286,7 @@ func TestMessagePack(t *testing.T) {
 				NSCount: 0,
 				ARCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "kilabit.info",
 				Type:  RecordTypeNS,
 				Class: RecordClassIN,
@@ -352,7 +352,7 @@ func TestMessagePack(t *testing.T) {
 				ANCount: 1,
 				ARCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "mail.kilabit.info",
 				Type:  RecordTypeCNAME,
 				Class: RecordClassIN,
@@ -396,7 +396,7 @@ func TestMessagePack(t *testing.T) {
 				IsRA:    true,
 				QDCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "kilabit.info",
 				Type:  RecordTypeSOA,
 				Class: RecordClassIN,
@@ -483,7 +483,7 @@ func TestMessagePack(t *testing.T) {
 				ANCount: 5,
 				ARCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "google.com",
 				Type:  RecordTypeMX,
 				Class: RecordClassIN,
@@ -581,7 +581,7 @@ func TestMessagePack(t *testing.T) {
 				IsRA:    true,
 				QDCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "google.com",
 				Type:  RecordTypeTXT,
 				Class: RecordClassIN,
@@ -642,7 +642,7 @@ func TestMessagePack(t *testing.T) {
 				ANCount: 1,
 				ARCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "google.com",
 				Type:  RecordTypeAAAA,
 				Class: RecordClassIN,
@@ -740,7 +740,7 @@ func TestMessagePack(t *testing.T) {
 				ANCount: 5,
 				ARCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "_xmpp-server._tcp.google.com",
 				Type:  RecordTypeSRV,
 				Class: RecordClassIN,
@@ -843,7 +843,7 @@ func TestMessageSetAuthoritativeAnswer(t *testing.T) {
 			IsAA:    true,
 			IsRD:    true,
 		},
-		Question: SectionQuestion{},
+		Question: MessageQuestion{},
 		packet:   make([]byte, maxUdpPacketSize),
 		dnameOff: make(map[string]uint16),
 	}
@@ -860,7 +860,7 @@ func TestMessageSetAuthoritativeAnswer(t *testing.T) {
 			IsRD: true,
 			IsRA: true,
 		},
-		Question: SectionQuestion{},
+		Question: MessageQuestion{},
 		packet:   make([]byte, maxUdpPacketSize),
 		dnameOff: make(map[string]uint16),
 	}
@@ -912,7 +912,7 @@ func TestMessageSetQuery(t *testing.T) {
 			IsAA:    true,
 			IsRD:    true,
 		},
-		Question: SectionQuestion{},
+		Question: MessageQuestion{},
 		packet:   make([]byte, maxUdpPacketSize),
 		dnameOff: make(map[string]uint16),
 	}
@@ -955,7 +955,7 @@ func TestMessageSetRecursionDesired(t *testing.T) {
 			IsAA:    true,
 			IsRD:    true,
 		},
-		Question: SectionQuestion{},
+		Question: MessageQuestion{},
 		packet:   make([]byte, maxUdpPacketSize),
 		dnameOff: make(map[string]uint16),
 	}
@@ -998,7 +998,7 @@ func TestMessageSetResponseCode(t *testing.T) {
 			IsAA:    true,
 			IsRD:    true,
 		},
-		Question: SectionQuestion{},
+		Question: MessageQuestion{},
 		packet:   make([]byte, maxUdpPacketSize),
 		dnameOff: make(map[string]uint16),
 	}
@@ -1069,7 +1069,7 @@ func TestMessageUnpack(t *testing.T) {
 				ANCount: 1,
 				ARCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "kilabit.info",
 				Type:  RecordTypeA,
 				Class: RecordClassIN,
@@ -1142,7 +1142,7 @@ func TestMessageUnpack(t *testing.T) {
 				NSCount: 0,
 				ARCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "kilabit.info",
 				Type:  RecordTypeNS,
 				Class: RecordClassIN,
@@ -1220,7 +1220,7 @@ func TestMessageUnpack(t *testing.T) {
 				ANCount: 1,
 				ARCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "mail.kilabit.info",
 				Type:  RecordTypeCNAME,
 				Class: RecordClassIN,
@@ -1278,7 +1278,7 @@ func TestMessageUnpack(t *testing.T) {
 				QDCount: 1,
 				ANCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "kilabit.info",
 				Type:  RecordTypeSOA,
 				Class: RecordClassIN,
@@ -1375,7 +1375,7 @@ func TestMessageUnpack(t *testing.T) {
 				ANCount: 5,
 				ARCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "google.com",
 				Type:  RecordTypeMX,
 				Class: RecordClassIN,
@@ -1522,7 +1522,7 @@ func TestMessageUnpack(t *testing.T) {
 				ANCount: 3,
 				ARCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "google.com",
 				Type:  RecordTypeTXT,
 				Class: RecordClassIN,
@@ -1612,7 +1612,7 @@ func TestMessageUnpack(t *testing.T) {
 				ANCount: 1,
 				ARCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "google.com",
 				Type:  RecordTypeAAAA,
 				Class: RecordClassIN,
@@ -1716,7 +1716,7 @@ func TestMessageUnpack(t *testing.T) {
 				ANCount: 5,
 				ARCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "_xmpp-server._tcp.google.com",
 				Type:  RecordTypeSRV,
 				Class: RecordClassIN,
diff --git a/lib/dns/section_question.go b/lib/dns/section_question.go
deleted file mode 100644
index c4a2cd71..00000000
--- a/lib/dns/section_question.go
+++ /dev/null
@@ -1,117 +0,0 @@
-// Copyright 2018, Shulhan <ms@kilabit.info>. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package dns
-
-import (
-	"fmt"
-	"strings"
-
-	libbytes "github.com/shuLhan/share/lib/bytes"
-)
-
-//
-// SectionQuestion The question section is used to carry the "question" in
-// most queries, i.e., the parameters that define what is being asked.  The
-// section contains QDCOUNT (usually 1) entries, each of the following format:
-//
-type SectionQuestion struct {
-	// A domain name represented as a sequence of labels, where each label
-	// consists of a length octet followed by that number of octets.  The
-	// domain name terminates with the zero length octet for the null
-	// label of the root.  Note that this field may be an odd number of
-	// octets; no padding is used.
-	Name string
-
-	// A two octet code which specifies the type of the query.  The values
-	// for this field include all codes valid for a TYPE field, together
-	// with some more general codes which can match more than one type of
-	// RR.
-	Type RecordType
-
-	// A two octet code that specifies the class of the query.  For
-	// example, the QCLASS field is IN for the Internet.
-	Class RecordClass
-}
-
-//
-// Reset the message question field to it's default values for query.
-//
-func (question *SectionQuestion) Reset() {
-	question.Name = question.Name[:0]
-	question.Type = RecordTypeA
-	question.Class = RecordClassIN
-}
-
-//
-// size return the section question size, length of name + 2 (1 octet for
-// beginning size plus 1 octet for end of label) + 2 octets of
-// rtype + 2 octets of rclass
-//
-func (question *SectionQuestion) size() int {
-	return len(question.Name) + 6
-}
-
-//
-// String will return the string representation of section question structure.
-//
-func (question *SectionQuestion) String() string {
-	return fmt.Sprintf("&{Name:%s Type:%s}", question.Name,
-		RecordTypeNames[question.Type])
-}
-
-//
-// unpack the DNS question section.
-//
-func (question *SectionQuestion) unpack(packet []byte) (err error) {
-	if len(packet) == 0 {
-		return nil
-	}
-
-	var sb strings.Builder
-	count := packet[0]
-	x := 1
-
-	for {
-		if count == 0 {
-			sb.WriteByte('.')
-			count = packet[x]
-			x++
-			if x >= len(packet) {
-				return fmt.Errorf("SectionQuestion.unpack: invalid question %q", packet)
-			}
-			continue
-		}
-		for y := byte(0); y < count; y++ {
-			if packet[x] >= 'A' && packet[x] <= 'Z' {
-				packet[x] += 32
-			}
-			sb.WriteByte(packet[x])
-			x++
-			if x >= len(packet) {
-				return fmt.Errorf("SectionQuestion.unpack: invalid question %q", packet)
-			}
-		}
-		count = packet[x]
-		x++
-		if count == 0 {
-			break
-		}
-		if x >= len(packet) {
-			return fmt.Errorf("SectionQuestion.unpack: invalid question %q", packet)
-		}
-		sb.WriteByte('.')
-	}
-
-	if x+4 > len(packet) {
-		return fmt.Errorf("SectionQuestion.unpack: invalid question %q", packet)
-	}
-
-	question.Name = sb.String()
-	question.Type = RecordType(libbytes.ReadUint16(packet, uint(x)))
-	x += 2
-	question.Class = RecordClass(libbytes.ReadUint16(packet, uint(x)))
-
-	return nil
-}
diff --git a/lib/dns/tcp_client_test.go b/lib/dns/tcp_client_test.go
index 7726bfc3..460d81a5 100644
--- a/lib/dns/tcp_client_test.go
+++ b/lib/dns/tcp_client_test.go
@@ -35,7 +35,7 @@ func TestTCPClientLookup(t *testing.T) {
 				QDCount: 1,
 				ANCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "kilabit.info",
 				Type:  RecordTypeA,
 				Class: RecordClassIN,
@@ -63,7 +63,7 @@ func TestTCPClientLookup(t *testing.T) {
 				QDCount: 1,
 				ANCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "kilabit.info",
 				Type:  RecordTypeSOA,
 				Class: RecordClassIN,
@@ -98,7 +98,7 @@ func TestTCPClientLookup(t *testing.T) {
 				QDCount: 1,
 				ANCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "kilabit.info",
 				Type:  RecordTypeTXT,
 				Class: RecordClassIN,
diff --git a/lib/dns/udp_client_example_test.go b/lib/dns/udp_client_example_test.go
index 0ccd9951..ec179633 100644
--- a/lib/dns/udp_client_example_test.go
+++ b/lib/dns/udp_client_example_test.go
@@ -20,7 +20,7 @@ func ExampleUDPClient() {
 
 	req := &dns.Message{
 		Header: dns.MessageHeader{},
-		Question: dns.SectionQuestion{
+		Question: dns.MessageQuestion{
 			Name:  "kilabit.info",
 			Type:  dns.RecordTypeA,
 			Class: dns.RecordClassIN,
diff --git a/lib/dns/udp_client_test.go b/lib/dns/udp_client_test.go
index 44489500..e00b1d24 100644
--- a/lib/dns/udp_client_test.go
+++ b/lib/dns/udp_client_test.go
@@ -35,7 +35,7 @@ func TestUDPClientLookup(t *testing.T) {
 				QDCount: 1,
 				ANCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "kilabit.info",
 				Type:  RecordTypeA,
 				Class: RecordClassIN,
@@ -63,7 +63,7 @@ func TestUDPClientLookup(t *testing.T) {
 				QDCount: 1,
 				ANCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "kilabit.info",
 				Type:  RecordTypeSOA,
 				Class: RecordClassIN,
@@ -98,7 +98,7 @@ func TestUDPClientLookup(t *testing.T) {
 				QDCount: 1,
 				ANCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "kilabit.info",
 				Type:  RecordTypeTXT,
 				Class: RecordClassIN,
@@ -125,7 +125,7 @@ func TestUDPClientLookup(t *testing.T) {
 				RCode:   RCodeErrServer,
 				QDCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "kilabit.info",
 				Type:  RecordTypeAAAA,
 				Class: RecordClassIN,
diff --git a/lib/dns/zone_file.go b/lib/dns/zone_file.go
index 896f9df9..80909c39 100644
--- a/lib/dns/zone_file.go
+++ b/lib/dns/zone_file.go
@@ -166,7 +166,7 @@ func (zone *ZoneFile) Add(rr *ResourceRecord) (err error) {
 			QDCount: 1,
 			ANCount: 1,
 		},
-		Question: SectionQuestion{
+		Question: MessageQuestion{
 			Name:  rr.Name,
 			Type:  rr.Type,
 			Class: rr.Class,
diff --git a/lib/dns/zone_file_test.go b/lib/dns/zone_file_test.go
index c69b1fa2..080cb6ca 100644
--- a/lib/dns/zone_file_test.go
+++ b/lib/dns/zone_file_test.go
@@ -169,7 +169,7 @@ VAXA    A       10.2.0.27
 				QDCount: 1,
 				ANCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "isi.edu",
 				Type:  RecordTypeSOA,
 				Class: RecordClassIN,
@@ -195,7 +195,7 @@ VAXA    A       10.2.0.27
 				QDCount: 1,
 				ANCount: 3,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "isi.edu",
 				Type:  RecordTypeNS,
 				Class: RecordClassIN,
@@ -225,7 +225,7 @@ VAXA    A       10.2.0.27
 				QDCount: 1,
 				ANCount: 2,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "isi.edu",
 				Type:  RecordTypeMX,
 				Class: RecordClassIN,
@@ -255,7 +255,7 @@ VAXA    A       10.2.0.27
 				QDCount: 1,
 				ANCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "a.isi.edu",
 				Type:  RecordTypeA,
 				Class: RecordClassIN,
@@ -273,7 +273,7 @@ VAXA    A       10.2.0.27
 				QDCount: 1,
 				ANCount: 2,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "venera.isi.edu",
 				Type:  RecordTypeA,
 				Class: RecordClassIN,
@@ -297,7 +297,7 @@ VAXA    A       10.2.0.27
 				QDCount: 1,
 				ANCount: 2,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "vaxa.isi.edu",
 				Type:  RecordTypeA,
 				Class: RecordClassIN,
@@ -400,7 +400,7 @@ relay IN CNAME relay.pair.com.
 				QDCount: 1,
 				ANCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "pcguide.com",
 				Type:  RecordTypeSOA,
 				Class: RecordClassIN,
@@ -426,7 +426,7 @@ relay IN CNAME relay.pair.com.
 				QDCount: 1,
 				ANCount: 2,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "pcguide.com",
 				Type:  RecordTypeNS,
 				Class: RecordClassIN,
@@ -450,7 +450,7 @@ relay IN CNAME relay.pair.com.
 				QDCount: 1,
 				ANCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "localhost.pcguide.com",
 				Type:  RecordTypeA,
 				Class: RecordClassIN,
@@ -468,7 +468,7 @@ relay IN CNAME relay.pair.com.
 				QDCount: 1,
 				ANCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "pcguide.com",
 				Type:  RecordTypeA,
 				Class: RecordClassIN,
@@ -486,7 +486,7 @@ relay IN CNAME relay.pair.com.
 				QDCount: 1,
 				ANCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "pcguide.com",
 				Type:  RecordTypeMX,
 				Class: RecordClassIN,
@@ -507,7 +507,7 @@ relay IN CNAME relay.pair.com.
 				QDCount: 1,
 				ANCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "www.pcguide.com",
 				Type:  RecordTypeCNAME,
 				Class: RecordClassIN,
@@ -525,7 +525,7 @@ relay IN CNAME relay.pair.com.
 				QDCount: 1,
 				ANCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "ftp.pcguide.com",
 				Type:  RecordTypeCNAME,
 				Class: RecordClassIN,
@@ -543,7 +543,7 @@ relay IN CNAME relay.pair.com.
 				QDCount: 1,
 				ANCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "mail.pcguide.com",
 				Type:  RecordTypeCNAME,
 				Class: RecordClassIN,
@@ -561,7 +561,7 @@ relay IN CNAME relay.pair.com.
 				QDCount: 1,
 				ANCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "relay.pcguide.com",
 				Type:  RecordTypeCNAME,
 				Class: RecordClassIN,
@@ -646,7 +646,7 @@ angularjs.doc       A  127.0.0.1
 				QDCount: 1,
 				ANCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "dev.kilabit.info",
 				Type:  RecordTypeA,
 				Class: RecordClassIN,
@@ -664,7 +664,7 @@ angularjs.doc       A  127.0.0.1
 				QDCount: 1,
 				ANCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "dev.kilabit.com",
 				Type:  RecordTypeA,
 				Class: RecordClassIN,
@@ -682,7 +682,7 @@ angularjs.doc       A  127.0.0.1
 				QDCount: 1,
 				ANCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "angularjs.doc.localdomain",
 				Type:  RecordTypeA,
 				Class: RecordClassIN,
@@ -755,7 +755,7 @@ func TestZoneParseTXT(t *testing.T) {
 				QDCount: 1,
 				ANCount: 1,
 			},
-			Question: SectionQuestion{
+			Question: MessageQuestion{
 				Name:  "kilabit.local",
 				Type:  RecordTypeTXT,
 				Class: RecordClassIN,