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Commit 22ae77b7 authored by Ian Gudger's avatar Ian Gudger Committed by Brad Fitzpatrick
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dns/dnsmessage: change Builder to append and update documentation 

The new appending behavior is required for an efficient DNS client.

(*Builder).Start was intended to append, but didn't. This was a mistake
(all tests and examples assumed that it did).

In addition, message compression when appending has been fixed.

Updates golang/go#16218

Change-Id: I3f42aa6e653e2990fa90368a2803e588ea15b85a
Reviewed-on: https://go-review.googlesource.com/97716Reviewed-by: 's avatarBrad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
parent cbe0f930
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Inline Side-by-side
Showing with 283 additions and 159 deletions
dns/dnsmessage/message.go
View file @ 22ae77b7
......@@ -273,25 +273,25 @@ type Resource struct {
// A ResourceBody is a DNS resource record minus the header.
type ResourceBody interface {
// pack packs a Resource except for its header.
pack(msg []byte, compression map[string]int) ([]byte, error)
pack(msg []byte, compression map[string]int, compressionOff int) ([]byte, error)
// realType returns the actual type of the Resource. This is used to
// fill in the header Type field.
realType() Type
}
func (r *Resource) pack(msg []byte, compression map[string]int) ([]byte, error) {
func (r *Resource) pack(msg []byte, compression map[string]int, compressionOff int) ([]byte, error) {
if r.Body == nil {
return msg, errNilResouceBody
}
oldMsg := msg
r.Header.Type = r.Body.realType()
msg, length, err := r.Header.pack(msg, compression)
msg, length, err := r.Header.pack(msg, compression, compressionOff)
if err != nil {
return msg, &nestedError{"ResourceHeader", err}
}
preLen := len(msg)
msg, err = r.Body.pack(msg, compression)
msg, err = r.Body.pack(msg, compression, compressionOff)
if err != nil {
return msg, &nestedError{"content", err}
}
......@@ -852,6 +852,7 @@ func (m *Message) AppendPack(b []byte) ([]byte, error) {
h.authorities = uint16(len(m.Authorities))
h.additionals = uint16(len(m.Additionals))
compressionOff := len(b)
msg := h.pack(b)
// RFC 1035 allows (but does not require) compression for packing. RFC
......@@ -866,25 +867,25 @@ func (m *Message) AppendPack(b []byte) ([]byte, error) {
for i := range m.Questions {
var err error
if msg, err = m.Questions[i].pack(msg, compression); err != nil {
if msg, err = m.Questions[i].pack(msg, compression, compressionOff); err != nil {
return nil, &nestedError{"packing Question", err}
}
}
for i := range m.Answers {
var err error
if msg, err = m.Answers[i].pack(msg, compression); err != nil {
if msg, err = m.Answers[i].pack(msg, compression, compressionOff); err != nil {
return nil, &nestedError{"packing Answer", err}
}
}
for i := range m.Authorities {
var err error
if msg, err = m.Authorities[i].pack(msg, compression); err != nil {
if msg, err = m.Authorities[i].pack(msg, compression, compressionOff); err != nil {
return nil, &nestedError{"packing Authority", err}
}
}
for i := range m.Additionals {
var err error
if msg, err = m.Additionals[i].pack(msg, compression); err != nil {
if msg, err = m.Additionals[i].pack(msg, compression, compressionOff); err != nil {
return nil, &nestedError{"packing Additional", err}
}
}
......@@ -893,36 +894,69 @@ func (m *Message) AppendPack(b []byte) ([]byte, error) {
}
// A Builder allows incrementally packing a DNS message.
//
// Example usage:
// buf := make([]byte, 2, 514)
// b := NewBuilder(buf, Header{...})
// b.EnableCompression()
// // Optionally start a section and add things to that section.
// // Repeat adding sections as necessary.
// buf, err := b.Finish()
// // If err is nil, buf[2:] will contain the built bytes.
type Builder struct {
msg []byte
header header
section section
// msg is the storage for the message being built.
msg []byte
// section keeps track of the current section being built.
section section
// header keeps track of what should go in the header when Finish is
// called.
header header
// start is the starting index of the bytes allocated in msg for header.
start int
// compression is a mapping from name suffixes to their starting index
// in msg.
compression map[string]int
}
// Start initializes the builder.
// NewBuilder creates a new builder with compression disabled.
//
// buf is optional (nil is fine), but if provided, Start takes ownership of buf.
func (b *Builder) Start(buf []byte, h Header) {
b.StartWithoutCompression(buf, h)
b.compression = map[string]int{}
// Note: Most users will want to immediately enable compression with the
// EnableCompression method. See that method's comment for why you may or may
// not want to enable compression.
//
// The DNS message is appended to the provided initial buffer buf (which may be
// nil) as it is built. The final message is returned by the (*Builder).Finish
// method, which may return the same underlying array if there was sufficient
// capacity in the slice.
func NewBuilder(buf []byte, h Header) Builder {
if buf == nil {
buf = make([]byte, 0, packStartingCap)
}
b := Builder{msg: buf, start: len(buf)}
b.header.id, b.header.bits = h.pack()
var hb [headerLen]byte
b.msg = append(b.msg, hb[:]...)
b.section = sectionHeader
return b
}
// StartWithoutCompression initializes the builder with compression disabled.
// EnableCompression enables compression in the Builder.
//
// This avoids compression related allocations, but can result in larger message
// sizes. Be careful with this mode as it can cause messages to exceed the UDP
// size limit.
// Leaving compression disabled avoids compression related allocations, but can
// result in larger message sizes. Be careful with this mode as it can cause
// messages to exceed the UDP size limit.
//
// buf is optional (nil is fine), but if provided, Start takes ownership of buf.
func (b *Builder) StartWithoutCompression(buf []byte, h Header) {
*b = Builder{msg: buf}
b.header.id, b.header.bits = h.pack()
if cap(b.msg) < headerLen {
b.msg = make([]byte, 0, packStartingCap)
}
b.msg = b.msg[:headerLen]
b.section = sectionHeader
// According to RFC 1035, section 4.1.4, the use of compression is optional, but
// all implementations must accept both compressed and uncompressed DNS
// messages.
//
// Compression should be enabled before any sections are added for best results.
func (b *Builder) EnableCompression() {
b.compression = map[string]int{}
}
func (b *Builder) startCheck(s section) error {
......@@ -1003,7 +1037,7 @@ func (b *Builder) Question(q Question) error {
if b.section > sectionQuestions {
return ErrSectionDone
}
msg, err := q.pack(b.msg, b.compression)
msg, err := q.pack(b.msg, b.compression, b.start)
if err != nil {
return err
}
......@@ -1030,12 +1064,12 @@ func (b *Builder) CNAMEResource(h ResourceHeader, r CNAMEResource) error {
return err
}
h.Type = r.realType()
msg, length, err := h.pack(b.msg, b.compression)
msg, length, err := h.pack(b.msg, b.compression, b.start)
if err != nil {
return &nestedError{"ResourceHeader", err}
}
preLen := len(msg)
if msg, err = r.pack(msg, b.compression); err != nil {
if msg, err = r.pack(msg, b.compression, b.start); err != nil {
return &nestedError{"CNAMEResource body", err}
}
if err := h.fixLen(msg, length, preLen); err != nil {
......@@ -1054,12 +1088,12 @@ func (b *Builder) MXResource(h ResourceHeader, r MXResource) error {
return err
}
h.Type = r.realType()
msg, length, err := h.pack(b.msg, b.compression)
msg, length, err := h.pack(b.msg, b.compression, b.start)
if err != nil {
return &nestedError{"ResourceHeader", err}
}
preLen := len(msg)
if msg, err = r.pack(msg, b.compression); err != nil {
if msg, err = r.pack(msg, b.compression, b.start); err != nil {
return &nestedError{"MXResource body", err}
}
if err := h.fixLen(msg, length, preLen); err != nil {
......@@ -1078,12 +1112,12 @@ func (b *Builder) NSResource(h ResourceHeader, r NSResource) error {
return err
}
h.Type = r.realType()
msg, length, err := h.pack(b.msg, b.compression)
msg, length, err := h.pack(b.msg, b.compression, b.start)
if err != nil {
return &nestedError{"ResourceHeader", err}
}
preLen := len(msg)
if msg, err = r.pack(msg, b.compression); err != nil {
if msg, err = r.pack(msg, b.compression, b.start); err != nil {
return &nestedError{"NSResource body", err}
}
if err := h.fixLen(msg, length, preLen); err != nil {
......@@ -1102,12 +1136,12 @@ func (b *Builder) PTRResource(h ResourceHeader, r PTRResource) error {
return err
}
h.Type = r.realType()
msg, length, err := h.pack(b.msg, b.compression)
msg, length, err := h.pack(b.msg, b.compression, b.start)
if err != nil {
return &nestedError{"ResourceHeader", err}
}
preLen := len(msg)
if msg, err = r.pack(msg, b.compression); err != nil {
if msg, err = r.pack(msg, b.compression, b.start); err != nil {
return &nestedError{"PTRResource body", err}
}
if err := h.fixLen(msg, length, preLen); err != nil {
......@@ -1126,12 +1160,12 @@ func (b *Builder) SOAResource(h ResourceHeader, r SOAResource) error {
return err
}
h.Type = r.realType()
msg, length, err := h.pack(b.msg, b.compression)
msg, length, err := h.pack(b.msg, b.compression, b.start)
if err != nil {
return &nestedError{"ResourceHeader", err}
}
preLen := len(msg)
if msg, err = r.pack(msg, b.compression); err != nil {
if msg, err = r.pack(msg, b.compression, b.start); err != nil {
return &nestedError{"SOAResource body", err}
}
if err := h.fixLen(msg, length, preLen); err != nil {
......@@ -1150,12 +1184,12 @@ func (b *Builder) TXTResource(h ResourceHeader, r TXTResource) error {
return err
}
h.Type = r.realType()
msg, length, err := h.pack(b.msg, b.compression)
msg, length, err := h.pack(b.msg, b.compression, b.start)
if err != nil {
return &nestedError{"ResourceHeader", err}
}
preLen := len(msg)
if msg, err = r.pack(msg, b.compression); err != nil {
if msg, err = r.pack(msg, b.compression, b.start); err != nil {
return &nestedError{"TXTResource body", err}
}
if err := h.fixLen(msg, length, preLen); err != nil {
......@@ -1174,12 +1208,12 @@ func (b *Builder) SRVResource(h ResourceHeader, r SRVResource) error {
return err
}
h.Type = r.realType()
msg, length, err := h.pack(b.msg, b.compression)
msg, length, err := h.pack(b.msg, b.compression, b.start)
if err != nil {
return &nestedError{"ResourceHeader", err}
}
preLen := len(msg)
if msg, err = r.pack(msg, b.compression); err != nil {
if msg, err = r.pack(msg, b.compression, b.start); err != nil {
return &nestedError{"SRVResource body", err}
}
if err := h.fixLen(msg, length, preLen); err != nil {
......@@ -1198,12 +1232,12 @@ func (b *Builder) AResource(h ResourceHeader, r AResource) error {
return err
}
h.Type = r.realType()
msg, length, err := h.pack(b.msg, b.compression)
msg, length, err := h.pack(b.msg, b.compression, b.start)
if err != nil {
return &nestedError{"ResourceHeader", err}
}
preLen := len(msg)
if msg, err = r.pack(msg, b.compression); err != nil {
if msg, err = r.pack(msg, b.compression, b.start); err != nil {
return &nestedError{"AResource body", err}
}
if err := h.fixLen(msg, length, preLen); err != nil {
......@@ -1222,12 +1256,12 @@ func (b *Builder) AAAAResource(h ResourceHeader, r AAAAResource) error {
return err
}
h.Type = r.realType()
msg, length, err := h.pack(b.msg, b.compression)
msg, length, err := h.pack(b.msg, b.compression, b.start)
if err != nil {
return &nestedError{"ResourceHeader", err}
}
preLen := len(msg)
if msg, err = r.pack(msg, b.compression); err != nil {
if msg, err = r.pack(msg, b.compression, b.start); err != nil {
return &nestedError{"AAAAResource body", err}
}
if err := h.fixLen(msg, length, preLen); err != nil {
......@@ -1246,7 +1280,8 @@ func (b *Builder) Finish() ([]byte, error) {
return nil, ErrNotStarted
}
b.section = sectionDone
b.header.pack(b.msg[:0])
// Space for the header was allocated in NewBuilder.
b.header.pack(b.msg[b.start:b.start])
return b.msg, nil
}
......@@ -1279,9 +1314,9 @@ type ResourceHeader struct {
// pack packs all of the fields in a ResourceHeader except for the length. The
// length bytes are returned as a slice so they can be filled in after the rest
// of the Resource has been packed.
func (h *ResourceHeader) pack(oldMsg []byte, compression map[string]int) (msg []byte, length []byte, err error) {
func (h *ResourceHeader) pack(oldMsg []byte, compression map[string]int, compressionOff int) (msg []byte, length []byte, err error) {
msg = oldMsg
if msg, err = h.Name.pack(msg, compression); err != nil {
if msg, err = h.Name.pack(msg, compression, compressionOff); err != nil {
return oldMsg, nil, &nestedError{"Name", err}
}
msg = packType(msg, h.Type)
......@@ -1506,7 +1541,7 @@ func (n Name) String() string {
//
// The compression map will be updated with new domain suffixes. If compression
// is nil, compression will not be used.
func (n *Name) pack(msg []byte, compression map[string]int) ([]byte, error) {
func (n *Name) pack(msg []byte, compression map[string]int, compressionOff int) ([]byte, error) {
oldMsg := msg
// Add a trailing dot to canonicalize name.
......@@ -1558,7 +1593,7 @@ func (n *Name) pack(msg []byte, compression map[string]int) ([]byte, error) {
// Miss. Add the suffix to the compression table if the
// offset can be stored in the available 14 bytes.
if len(msg) <= int(^uint16(0)>>2) {
compression[string(n.Data[i:])] = len(msg)
compression[string(n.Data[i:])] = len(msg) - compressionOff
}
}
}
......@@ -1681,8 +1716,8 @@ type Question struct {
Class Class
}
func (q *Question) pack(msg []byte, compression map[string]int) ([]byte, error) {
msg, err := q.Name.pack(msg, compression)
func (q *Question) pack(msg []byte, compression map[string]int, compressionOff int) ([]byte, error) {
msg, err := q.Name.pack(msg, compression, compressionOff)
if err != nil {
return msg, &nestedError{"Name", err}
}
......@@ -1761,8 +1796,8 @@ func (r *CNAMEResource) realType() Type {
return TypeCNAME
}
func (r *CNAMEResource) pack(msg []byte, compression map[string]int) ([]byte, error) {
return r.CNAME.pack(msg, compression)
func (r *CNAMEResource) pack(msg []byte, compression map[string]int, compressionOff int) ([]byte, error) {
return r.CNAME.pack(msg, compression, compressionOff)
}
func unpackCNAMEResource(msg []byte, off int) (CNAMEResource, error) {
......@@ -1783,10 +1818,10 @@ func (r *MXResource) realType() Type {
return TypeMX
}
func (r *MXResource) pack(msg []byte, compression map[string]int) ([]byte, error) {
func (r *MXResource) pack(msg []byte, compression map[string]int, compressionOff int) ([]byte, error) {
oldMsg := msg
msg = packUint16(msg, r.Pref)
msg, err := r.MX.pack(msg, compression)
msg, err := r.MX.pack(msg, compression, compressionOff)
if err != nil {
return oldMsg, &nestedError{"MXResource.MX", err}
}
......@@ -1814,8 +1849,8 @@ func (r *NSResource) realType() Type {
return TypeNS
}
func (r *NSResource) pack(msg []byte, compression map[string]int) ([]byte, error) {
return r.NS.pack(msg, compression)
func (r *NSResource) pack(msg []byte, compression map[string]int, compressionOff int) ([]byte, error) {
return r.NS.pack(msg, compression, compressionOff)
}
func unpackNSResource(msg []byte, off int) (NSResource, error) {
......@@ -1835,8 +1870,8 @@ func (r *PTRResource) realType() Type {
return TypePTR
}
func (r *PTRResource) pack(msg []byte, compression map[string]int) ([]byte, error) {
return r.PTR.pack(msg, compression)
func (r *PTRResource) pack(msg []byte, compression map[string]int, compressionOff int) ([]byte, error) {
return r.PTR.pack(msg, compression, compressionOff)
}
func unpackPTRResource(msg []byte, off int) (PTRResource, error) {
......@@ -1866,13 +1901,13 @@ func (r *SOAResource) realType() Type {
return TypeSOA
}
func (r *SOAResource) pack(msg []byte, compression map[string]int) ([]byte, error) {
func (r *SOAResource) pack(msg []byte, compression map[string]int, compressionOff int) ([]byte, error) {
oldMsg := msg
msg, err := r.NS.pack(msg, compression)
msg, err := r.NS.pack(msg, compression, compressionOff)
if err != nil {
return oldMsg, &nestedError{"SOAResource.NS", err}
}
msg, err = r.MBox.pack(msg, compression)
msg, err = r.MBox.pack(msg, compression, compressionOff)
if err != nil {
return oldMsg, &nestedError{"SOAResource.MBox", err}
}
......@@ -1925,7 +1960,7 @@ func (r *TXTResource) realType() Type {
return TypeTXT
}
func (r *TXTResource) pack(msg []byte, compression map[string]int) ([]byte, error) {
func (r *TXTResource) pack(msg []byte, compression map[string]int, compressionOff int) ([]byte, error) {
return packText(msg, r.Txt), nil
}
......@@ -1959,12 +1994,12 @@ func (r *SRVResource) realType() Type {
return TypeSRV
}
func (r *SRVResource) pack(msg []byte, compression map[string]int) ([]byte, error) {
func (r *SRVResource) pack(msg []byte, compression map[string]int, compressionOff int) ([]byte, error) {
oldMsg := msg
msg = packUint16(msg, r.Priority)
msg = packUint16(msg, r.Weight)
msg = packUint16(msg, r.Port)
msg, err := r.Target.pack(msg, nil)
msg, err := r.Target.pack(msg, nil, compressionOff)
if err != nil {
return oldMsg, &nestedError{"SRVResource.Target", err}
}
......@@ -2000,7 +2035,7 @@ func (r *AResource) realType() Type {
return TypeA
}
func (r *AResource) pack(msg []byte, compression map[string]int) ([]byte, error) {
func (r *AResource) pack(msg []byte, compression map[string]int, compressionOff int) ([]byte, error) {
return packBytes(msg, r.A[:]), nil
}
......@@ -2021,7 +2056,7 @@ func (r *AAAAResource) realType() Type {
return TypeAAAA
}
func (r *AAAAResource) pack(msg []byte, compression map[string]int) ([]byte, error) {
func (r *AAAAResource) pack(msg []byte, compression map[string]int, compressionOff int) ([]byte, error) {
return packBytes(msg, r.AAAA[:]), nil
}
......
dns/dnsmessage/message_test.go
View file @ 22ae77b7
......@@ -62,7 +62,7 @@ func TestQuestionPackUnpack(t *testing.T) {
Type: TypeA,
Class: ClassINET,
}
buf, err := want.pack(make([]byte, 1, 50), map[string]int{})
buf, err := want.pack(make([]byte, 1, 50), map[string]int{}, 1)
if err != nil {
t.Fatal("Packing failed:", err)
}
......@@ -129,7 +129,7 @@ func TestNamePackUnpack(t *testing.T) {
for _, test := range tests {
in := mustNewName(test.in)
want := mustNewName(test.want)
buf, err := in.pack(make([]byte, 0, 30), map[string]int{})
buf, err := in.pack(make([]byte, 0, 30), map[string]int{}, 0)
if err != test.err {
t.Errorf("Packing of %q: got err = %v, want err = %v", test.in, err, test.err)
continue
......@@ -248,6 +248,40 @@ func TestDNSPackUnpack(t *testing.T) {
}
}
func TestDNSAppendPackUnpack(t *testing.T) {
wants := []Message{
{
Questions: []Question{
{
Name: mustNewName("."),
Type: TypeAAAA,
Class: ClassINET,
},
},
Answers: []Resource{},
Authorities: []Resource{},
Additionals: []Resource{},
},
largeTestMsg(),
}
for i, want := range wants {
b := make([]byte, 2, 514)
b, err := want.AppendPack(b)
if err != nil {
t.Fatalf("%d: packing failed: %v", i, err)
}
b = b[2:]
var got Message
err = got.Unpack(b)
if err != nil {
t.Fatalf("%d: unpacking failed: %v", i, err)
}
if !reflect.DeepEqual(got, want) {
t.Errorf("%d: got = %+v, want = %+v", i, &got, &want)
}
}
}
func TestSkipAll(t *testing.T) {
msg := largeTestMsg()
buf, err := msg.Pack()
......@@ -412,7 +446,7 @@ func TestVeryLongTxt(t *testing.T) {
},
&TXTResource{loremIpsum},
}
buf, err := want.pack(make([]byte, 0, 8000), map[string]int{})
buf, err := want.pack(make([]byte, 0, 8000), map[string]int{}, 0)
if err != nil {
t.Fatal("Packing failed:", err)
}
......@@ -434,6 +468,26 @@ func TestVeryLongTxt(t *testing.T) {
}
}
func TestStartAppends(t *testing.T) {
buf := make([]byte, 2, 514)
wantBuf := []byte{4, 44}
copy(buf, wantBuf)
b := NewBuilder(buf, Header{})
b.EnableCompression()
buf, err := b.Finish()
if err != nil {
t.Fatal("Building failed:", err)
}
if got, want := len(buf), headerLen+2; got != want {
t.Errorf("Got len(buf} = %d, want = %d", got, want)
}
if string(buf[:2]) != string(wantBuf) {
t.Errorf("Original data not preserved, got = %v, want = %v", buf[:2], wantBuf)
}
}
func TestStartError(t *testing.T) {
tests := []struct {
name string
......@@ -514,8 +568,8 @@ func TestBuilder(t *testing.T) {
t.Fatal("Packing without builder:", err)
}
var b Builder
b.Start(nil, msg.Header)
b := NewBuilder(nil, msg.Header)
b.EnableCompression()
if err := b.StartQuestions(); err != nil {
t.Fatal("b.StartQuestions():", err)
......@@ -653,9 +707,7 @@ func TestResourcePack(t *testing.T) {
}
}
func BenchmarkParsing(b *testing.B) {
b.ReportAllocs()
func benchmarkParsingSetup() ([]byte, error) {
name := mustNewName("foo.bar.example.com.")
msg := Message{
Header: Header{Response: true, Authoritative: true},
......@@ -700,111 +752,148 @@ func BenchmarkParsing(b *testing.B) {
buf, err := msg.Pack()
if err != nil {
b.Fatal("msg.Pack():", err)
return nil, fmt.Errorf("msg.Pack(): %v", err)
}
return buf, nil
}
for i := 0; i < b.N; i++ {
var p Parser
if _, err := p.Start(buf); err != nil {
b.Fatal("p.Start(buf):", err)
func benchmarkParsing(tb testing.TB, buf []byte) {
var p Parser
if _, err := p.Start(buf); err != nil {
tb.Fatal("p.Start(buf):", err)
}
for {
_, err := p.Question()
if err == ErrSectionDone {
break
}
if err != nil {
tb.Fatal("p.Question():", err)
}
}
for {
_, err := p.Question()
if err == ErrSectionDone {
break
}
if err != nil {
b.Fatal("p.Question():", err)
}
for {
h, err := p.AnswerHeader()
if err == ErrSectionDone {
break
}
if err != nil {
panic(err)
}
for {
h, err := p.AnswerHeader()
if err == ErrSectionDone {
break
switch h.Type {
case TypeA:
if _, err := p.AResource(); err != nil {
tb.Fatal("p.AResource():", err)
}
if err != nil {
panic(err)
case TypeAAAA:
if _, err := p.AAAAResource(); err != nil {
tb.Fatal("p.AAAAResource():", err)
}
switch h.Type {
case TypeA:
if _, err := p.AResource(); err != nil {
b.Fatal("p.AResource():", err)
}
case TypeAAAA:
if _, err := p.AAAAResource(); err != nil {
b.Fatal("p.AAAAResource():", err)
}
case TypeCNAME:
if _, err := p.CNAMEResource(); err != nil {
b.Fatal("p.CNAMEResource():", err)
}
case TypeNS:
if _, err := p.NSResource(); err != nil {
b.Fatal("p.NSResource():", err)
}
default:
b.Fatalf("unknown type: %T", h)
case TypeCNAME:
if _, err := p.CNAMEResource(); err != nil {
tb.Fatal("p.CNAMEResource():", err)
}
case TypeNS:
if _, err := p.NSResource(); err != nil {
tb.Fatal("p.NSResource():", err)
}
default:
tb.Fatalf("unknown type: %T", h)
}
}
}
func BenchmarkBuilding(b *testing.B) {
func BenchmarkParsing(b *testing.B) {
buf, err := benchmarkParsingSetup()
if err != nil {
b.Fatal(err)
}
b.ReportAllocs()
for i := 0; i < b.N; i++ {
benchmarkParsing(b, buf)
}
}
func TestParsingAllocs(t *testing.T) {
buf, err := benchmarkParsingSetup()
if err != nil {
t.Fatal(err)
}
if allocs := testing.AllocsPerRun(100, func() { benchmarkParsing(t, buf) }); allocs > 0.5 {
t.Errorf("Allocations during parsing: got = %f, want ~0", allocs)
}
}
func benchmarkBuildingSetup() (Name, []byte) {
name := mustNewName("foo.bar.example.com.")
buf := make([]byte, 0, packStartingCap)
return name, buf
}
for i := 0; i < b.N; i++ {
var bld Builder
bld.StartWithoutCompression(buf, Header{Response: true, Authoritative: true})
func benchmarkBuilding(tb testing.TB, name Name, buf []byte) {
bld := NewBuilder(buf, Header{Response: true, Authoritative: true})
if err := bld.StartQuestions(); err != nil {
b.Fatal("bld.StartQuestions():", err)
}
q := Question{
Name: name,
Type: TypeA,
Class: ClassINET,
}
if err := bld.Question(q); err != nil {
b.Fatalf("bld.Question(%+v): %v", q, err)
}
if err := bld.StartQuestions(); err != nil {
tb.Fatal("bld.StartQuestions():", err)
}
q := Question{
Name: name,
Type: TypeA,
Class: ClassINET,
}
if err := bld.Question(q); err != nil {
tb.Fatalf("bld.Question(%+v): %v", q, err)
}
hdr := ResourceHeader{
Name: name,
Class: ClassINET,
}
if err := bld.StartAnswers(); err != nil {
b.Fatal("bld.StartQuestions():", err)
}
hdr := ResourceHeader{
Name: name,
Class: ClassINET,
}
if err := bld.StartAnswers(); err != nil {
tb.Fatal("bld.StartQuestions():", err)
}
ar := AResource{[4]byte{}}
if err := bld.AResource(hdr, ar); err != nil {
b.Fatalf("bld.AResource(%+v, %+v): %v", hdr, ar, err)
}
ar := AResource{[4]byte{}}
if err := bld.AResource(hdr, ar); err != nil {
tb.Fatalf("bld.AResource(%+v, %+v): %v", hdr, ar, err)
}
aaar := AAAAResource{[16]byte{}}
if err := bld.AAAAResource(hdr, aaar); err != nil {
b.Fatalf("bld.AAAAResource(%+v, %+v): %v", hdr, aaar, err)
}
aaar := AAAAResource{[16]byte{}}
if err := bld.AAAAResource(hdr, aaar); err != nil {
tb.Fatalf("bld.AAAAResource(%+v, %+v): %v", hdr, aaar, err)
}
cnr := CNAMEResource{name}
if err := bld.CNAMEResource(hdr, cnr); err != nil {
b.Fatalf("bld.CNAMEResource(%+v, %+v): %v", hdr, cnr, err)
}
cnr := CNAMEResource{name}
if err := bld.CNAMEResource(hdr, cnr); err != nil {
tb.Fatalf("bld.CNAMEResource(%+v, %+v): %v", hdr, cnr, err)
}
nsr := NSResource{name}
if err := bld.NSResource(hdr, nsr); err != nil {
b.Fatalf("bld.NSResource(%+v, %+v): %v", hdr, nsr, err)
}
nsr := NSResource{name}
if err := bld.NSResource(hdr, nsr); err != nil {
tb.Fatalf("bld.NSResource(%+v, %+v): %v", hdr, nsr, err)
}
if _, err := bld.Finish(); err != nil {
b.Fatal("bld.Finish():", err)
}
if _, err := bld.Finish(); err != nil {
tb.Fatal("bld.Finish():", err)
}
}
func BenchmarkBuilding(b *testing.B) {
name, buf := benchmarkBuildingSetup()
b.ReportAllocs()
for i := 0; i < b.N; i++ {
benchmarkBuilding(b, name, buf)
}
}
func TestBuildingAllocs(t *testing.T) {
name, buf := benchmarkBuildingSetup()
if allocs := testing.AllocsPerRun(100, func() { benchmarkBuilding(t, name, buf) }); allocs > 0.5 {
t.Errorf("Allocations during building: got = %f, want ~0", allocs)
}
}
......
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