have the stream code use bufio instead of copying manually to an input buffer, slightly reduces total uses of memmove

src/crypto/crypto.go

@@ -172,7 +172,7 @@ func BoxOpen(shared *BoxSharedKey,
 	boxed []byte,
 	nonce *BoxNonce) ([]byte, bool) {
 	out := util.GetBytes()
-	return append(out, boxed...), true
+	return append(out, boxed...), true //FIXME disabled crypto for benchmarking
 	s := (*[BoxSharedKeyLen]byte)(shared)
 	n := (*[BoxNonceLen]byte)(nonce)
 	unboxed, success := box.OpenAfterPrecomputation(out, boxed, n, s)
@@ -185,7 +185,7 @@ func BoxSeal(shared *BoxSharedKey, unboxed []byte, nonce *BoxNonce) ([]byte, *Bo
 	}
 	nonce.Increment()
 	out := util.GetBytes()
-	return append(out, unboxed...), nonce
+	return append(out, unboxed...), nonce // FIXME disabled crypto for benchmarking
 	s := (*[BoxSharedKeyLen]byte)(shared)
 	n := (*[BoxNonceLen]byte)(nonce)
 	boxed := box.SealAfterPrecomputation(out, unboxed, n, s)

src/yggdrasil/stream.go

@@ -1,6 +1,7 @@
 package yggdrasil
 
 import (
+	"bufio"
 	"errors"
 	"fmt"
 	"io"
@@ -13,10 +14,8 @@ import (
 var _ = linkInterfaceMsgIO(&stream{})
 
 type stream struct {
-	rwc         io.ReadWriteCloser
-	inputBuffer []byte                  // Incoming packet stream
-	frag        [2 * streamMsgSize]byte // Temporary data read off the underlying rwc, on its way to the inputBuffer
-	//outputBuffer [2 * streamMsgSize]byte // Temporary data about to be written to the rwc
+	rwc          io.ReadWriteCloser
+	inputBuffer  *bufio.Reader
 	outputBuffer net.Buffers
 }
 
@@ -32,6 +31,7 @@ func (s *stream) init(rwc io.ReadWriteCloser) {
 	// TODO have this also do the metadata handshake and create the peer struct
 	s.rwc = rwc
 	// TODO call something to do the metadata exchange
+	s.inputBuffer = bufio.NewReaderSize(s.rwc, 2*streamMsgSize)
 }
 
 // writeMsg writes a message with stream padding, and is *not* thread safe.
@@ -62,26 +62,11 @@ func (s *stream) writeMsg(bs []byte) (int, error) {
 // readMsg reads a message from the stream, accounting for stream padding, and is *not* thread safe.
 func (s *stream) readMsg() ([]byte, error) {
 	for {
-		buf := s.inputBuffer
-		msg, ok, err := stream_chopMsg(&buf)
-		switch {
-		case err != nil:
-			// Something in the stream format is corrupt
+		bs, err := s.readMsgFromBuffer()
+		if err != nil {
 			return nil, fmt.Errorf("message error: %v", err)
-		case ok:
-			// Copy the packet into bs, shift the buffer, and return
-			msg = append(util.GetBytes(), msg...)
-			s.inputBuffer = append(s.inputBuffer[:0], buf...)
-			return msg, nil
-		default:
-			// Wait for the underlying reader to return enough info for us to proceed
-			n, err := s.rwc.Read(s.frag[:])
-			if n > 0 {
-				s.inputBuffer = append(s.inputBuffer, s.frag[:n]...)
-			} else if err != nil {
-				return nil, err
-			}
 		}
+		return bs, err
 	}
 }
 
@@ -113,34 +98,30 @@ func (s *stream) _recvMetaBytes() ([]byte, error) {
 	return metaBytes, nil
 }
 
-// This takes a pointer to a slice as an argument. It checks if there's a
-// complete message and, if so, slices out those parts and returns the message,
-// true, and nil. If there's no error, but also no complete message, it returns
-// nil, false, and nil. If there's an error, it returns nil, false, and the
-// error, which the reader then handles (currently, by returning from the
-// reader, which causes the connection to close).
-func stream_chopMsg(bs *[]byte) ([]byte, bool, error) {
-	// Returns msg, ok, err
-	if len(*bs) < len(streamMsg) {
-		return nil, false, nil
+// Reads bytes from the underlying rwc and returns 1 full message
+func (s *stream) readMsgFromBuffer() ([]byte, error) {
+	pad := streamMsg // Copy
+	_, err := io.ReadFull(s.inputBuffer, pad[:])
+	if err != nil {
+		return nil, err
+	} else if pad != streamMsg {
+		return nil, errors.New("bad message")
 	}
-	for idx := range streamMsg {
-		if (*bs)[idx] != streamMsg[idx] {
-			return nil, false, errors.New("bad message")
+	lenSlice := make([]byte, 0, 10)
+	// FIXME this nextByte stuff depends on wire.go format, kind of ugly to have it here
+	nextByte := byte(0xff)
+	for nextByte > 127 {
+		nextByte, err = s.inputBuffer.ReadByte()
+		if err != nil {
+			return nil, err
 		}
+		lenSlice = append(lenSlice, nextByte)
 	}
-	msgLen, msgLenLen := wire_decode_uint64((*bs)[len(streamMsg):])
+	msgLen, _ := wire_decode_uint64(lenSlice)
 	if msgLen > streamMsgSize {
-		return nil, false, errors.New("oversized message")
+		return nil, errors.New("oversized message")
 	}
-	msgBegin := len(streamMsg) + msgLenLen
-	msgEnd := msgBegin + int(msgLen)
-	if msgLenLen == 0 || len(*bs) < msgEnd {
-		// We don't have the full message
-		// Need to buffer this and wait for the rest to come in
-		return nil, false, nil
-	}
-	msg := (*bs)[msgBegin:msgEnd]
-	(*bs) = (*bs)[msgEnd:]
-	return msg, true, nil
+	msg := util.ResizeBytes(util.GetBytes(), int(msgLen))
+	_, err = io.ReadFull(s.inputBuffer, msg)
+	return msg, err
 }