Change the framing Encoder/Decoder to take the destination slice.

In theory this is easier on the garbage collector.  Probably could
reuse more of the intermediary buffers by stashing them in the
connection state, but that makes the code kind of messy.  This should
be an improvement.

1 files changed, 11 insertions, 10 deletions

diff --git a/packet.go b/packet.go
index 339a86d..6f9eb03 100644
--- a/packet.go
+++ b/packet.go
@@ -100,18 +100,18 @@ func (c *Obfs4Conn) producePacket(w io.Writer, pktType uint8, data []byte, padLe
 	pktLen := packetOverhead + len(data) + int(padLen)
 
 	// Encode the packet in an AEAD frame.
-	// TODO: Change Encode to write into frame directly
-	var frame []byte
-	_, frame, err = c.encoder.Encode(pkt[:pktLen])
+	var frame [framing.MaximumSegmentLength]byte
+	frameLen := 0
+	frameLen, err = c.encoder.Encode(frame[:], pkt[:pktLen])
 	if err != nil {
 		// All encoder errors are fatal.
 		return
 	}
 	var wrLen int
-	wrLen, err = w.Write(frame)
+	wrLen, err = w.Write(frame[:frameLen])
 	if err != nil {
 		return
-	} else if wrLen < len(frame) {
+	} else if wrLen < frameLen {
 		err = io.ErrShortWrite
 		return
 	}
@@ -132,22 +132,23 @@ func (c *Obfs4Conn) consumeFramedPackets(w io.Writer) (n int, err error) {
 	}
 	c.receiveBuffer.Write(buf[:rdLen])
 
+	var decoded [framing.MaximumFramePayloadLength]byte
 	for c.receiveBuffer.Len() > 0 {
 		// Decrypt an AEAD frame.
-		// TODO: Change Decode to write into packet directly
-		var pkt []byte
-		_, pkt, err = c.decoder.Decode(&c.receiveBuffer)
+		decLen := 0
+		decLen, err = c.decoder.Decode(decoded[:], &c.receiveBuffer)
 		if err == framing.ErrAgain {
 			// The accumulated payload does not make up a full frame.
 			return
 		} else if err != nil {
 			break
-		} else if len(pkt) < packetOverhead {
-			err = InvalidPacketLengthError(len(pkt))
+		} else if decLen < packetOverhead {
+			err = InvalidPacketLengthError(decLen)
 			break
 		}
 
 		// Decode the packet.
+		pkt := decoded[0:decLen]
 		pktType := pkt[0]
 		payloadLen := binary.BigEndian.Uint16(pkt[1:])
 		if int(payloadLen) > len(pkt)-packetOverhead {