forked from TrueCloudLab/restic
crypto: Add buffer management to writer
benchmarks:
benchmark old ns/op new ns/op delta
BenchmarkEncryptWriter 37032949 37754353 +1.95%
BenchmarkEncrypt 35989611 36344593 +0.99%
BenchmarkDecryptReader 38274466 38282979 +0.02%
BenchmarkEncryptDecryptReader 77506506 77088612 -0.54%
BenchmarkDecrypt 36219298 36128875 -0.25%
benchmark old MB/s new MB/s speedup
BenchmarkEncryptWriter 226.52 222.19 0.98x
BenchmarkEncrypt 233.08 230.81 0.99x
BenchmarkDecryptReader 219.17 219.12 1.00x
BenchmarkEncryptDecryptReader 108.23 108.82 1.01x
BenchmarkDecrypt 231.61 232.19 1.00x
benchmark old allocs new allocs delta
BenchmarkEncryptWriter 20 16 -20.00%
BenchmarkEncrypt 12 12 +0.00%
BenchmarkDecryptReader 13 13 +0.00%
BenchmarkEncryptDecryptReader 32 27 -15.62%
BenchmarkDecrypt 10 10 +0.00%
benchmark old bytes new bytes delta
BenchmarkEncryptWriter 1020064 170331 -83.30%
BenchmarkEncrypt 1600 1600 +0.00%
BenchmarkDecryptReader 841070 842094 +0.12%
BenchmarkEncryptDecryptReader 3027433 845129 -72.08%
BenchmarkDecrypt 1573 1573 +0.00%
This commit is contained in:
Alexander Neumann
parent
387082f983
commit
9c43688d1a
2 changed files with 44 additions and 70 deletions
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@ -2,7 +2,7 @@ package crypto
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import "sync"
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const defaultBufSize = 2048
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const defaultBufSize = 32 * 1024 // 32KiB
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var bufPool = sync.Pool{
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New: func() interface{} {
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104
crypto/writer.go
104
crypto/writer.go
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@ -1,110 +1,84 @@
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package crypto
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import (
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"bytes"
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"crypto/aes"
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"crypto/cipher"
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"errors"
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"fmt"
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"io"
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"sync"
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)
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type encryptWriter struct {
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iv []byte
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wroteIV bool
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data *bytes.Buffer
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data []byte
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key *Key
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s cipher.Stream
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w io.Writer
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origWr io.Writer
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err error // remember error writing iv
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closed bool
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}
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func (e *encryptWriter) Close() error {
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// write mac
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mac := poly1305Sign(e.data.Bytes()[ivSize:], e.data.Bytes()[:ivSize], &e.key.Sign)
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_, err := e.origWr.Write(mac)
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if e.closed {
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return errors.New("Close() called on already closed writer")
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}
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e.closed = true
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// encrypt everything
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iv, c := e.data[:ivSize], e.data[ivSize:]
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e.s.XORKeyStream(c, c)
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// compute mac
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mac := poly1305Sign(c, iv, &e.key.Sign)
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e.data = append(e.data, mac...)
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// write everything
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n, err := e.w.Write(e.data)
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if err != nil {
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return err
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}
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// return buffer
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bufPool.Put(e.data.Bytes())
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if n != len(e.data) {
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return errors.New("not all bytes written")
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}
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// return buffer to pool
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freeBuffer(e.data)
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return nil
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}
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const encryptWriterChunkSize = 512 * 1024 // 512 KiB
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var encryptWriterBufPool = sync.Pool{
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New: func() interface{} {
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return make([]byte, encryptWriterChunkSize)
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},
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}
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func (e *encryptWriter) Write(p []byte) (int, error) {
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// write iv first
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if !e.wroteIV {
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_, e.err = e.origWr.Write(e.iv[:])
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e.wroteIV = true
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// if e.data is too small, return it to the buffer and create new slice
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if cap(e.data) < len(e.data)+len(p) {
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b := make([]byte, len(e.data), len(e.data)*2)
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copy(b, e.data)
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freeBuffer(e.data)
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e.data = b
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}
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if e.err != nil {
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return 0, e.err
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}
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buf := encryptWriterBufPool.Get().([]byte)
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defer encryptWriterBufPool.Put(buf)
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written := 0
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for len(p) > 0 {
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max := len(p)
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if max > encryptWriterChunkSize {
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max = encryptWriterChunkSize
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}
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e.s.XORKeyStream(buf, p[:max])
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n, err := e.w.Write(buf[:max])
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if n != max {
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if err == nil { // should never happen
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err = io.ErrShortWrite
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}
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}
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written += n
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p = p[n:]
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if err != nil {
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e.err = err
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return written, err
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}
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}
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return written, nil
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// copy new data to e.data
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e.data = append(e.data, p...)
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return len(p), nil
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}
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// EncryptTo buffers data written to the returned io.WriteCloser. When Close()
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// is called, the data is encrypted an written to the underlying writer.
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// is called, the data is encrypted and written to the underlying writer.
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func EncryptTo(ks *Key, wr io.Writer) io.WriteCloser {
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ew := &encryptWriter{
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iv: newIV(),
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data: bytes.NewBuffer(getBuffer()[:0]),
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data: getBuffer(),
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key: ks,
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origWr: wr,
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}
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// buffer iv for mac
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_, err := ew.data.Write(ew.iv[:])
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if err != nil {
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panic(err)
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}
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ew.data = ew.data[:ivSize]
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copy(ew.data, newIV())
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c, err := aes.NewCipher(ks.Encrypt[:])
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if err != nil {
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panic(fmt.Sprintf("unable to create cipher: %v", err))
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}
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ew.s = cipher.NewCTR(c, ew.iv[:])
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ew.w = io.MultiWriter(ew.data, wr)
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ew.s = cipher.NewCTR(c, ew.data[:ivSize])
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ew.w = wr
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return ew
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}
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