Redesign shadow payload

Makefile

@@ -18,5 +18,9 @@ server: build kill
 	$(PWD)/sower -n QUIC -logtostderr -v 1
 
 run: build kill
-	$(PWD)/sower -n QUIC -logtostderr -v 1 &
-	sudo $(PWD)/sower -f conf/sower.toml -logtostderr
+	$(PWD)/sower -n QUIC -logtostderr -v 1  &
+	sudo $(PWD)/sower -f conf/sower.toml -logtostderr &
+	sleep 1
+	@curl 127.0.0.1
+	sleep 1
+	sudo pkill -9 sower || true

proxy/client.go

@@ -25,6 +25,7 @@ func StartClient(netType, server, password string) {
 	case TCP.String():
 		client = tcp.NewClient()
 	}
+	glog.Infoln("Client started.")
 
 	for {
 		conn := <-connCh

proxy/server.go

@@ -37,6 +37,7 @@ func StartServer(netType, port, password string) {
 	if err != nil {
 		glog.Fatalf("listen %v fail: %s", port, err)
 	}
+	glog.Infoln("Server started.")
 
 	for {
 		conn := <-connCh

shadow/shadow.go

@@ -5,100 +5,83 @@ import (
 	"crypto/cipher"
 	"encoding/binary"
 	"io"
-	"log"
 	"math/rand"
 	"net"
 
 	"github.com/pkg/errors"
 )
 
-func init() {
-	log.SetFlags(log.Ltime | log.Lshortfile)
-}
-
-var MTU = 1350 //MTU must little than 0xFFFF
+const MAX_SIZE = 0xFFFF
 
 type conn struct {
-	dataSize     int
+	maxSize      int
 	aead         cipher.AEAD
 	encryptNonce func() []byte
 	decryptNonce func() []byte
 	writeBuf     []byte
 	readBuf      []byte
 	readOffset   int
-	readLast     int
 	net.Conn
 }
 
 func (c *conn) Read(b []byte) (n int, err error) {
-	bLength := len(b)
-	offset := 0
-	switch c.readOffset {
-	case -1:
-		return 0, io.EOF
-	case 0: // read from conn
-	default: // read from buffer
-		offset = copy(b, c.readBuf[c.readOffset:c.readLast])
-		if offset+c.readOffset < c.readLast {
-			c.readOffset += offset
-			return offset, nil
-		}
+	// read from buffer
+	if c.readOffset != 0 {
+		dataSize := len(c.readBuf) - c.aead.Overhead()
+		n = copy(b, c.readBuf[c.readOffset:dataSize])
+		c.readOffset += n
 
-		if c.readLast < c.dataSize {
-			c.readOffset = -1
-			return offset, io.EOF
+		if c.readOffset == dataSize {
+			c.readOffset = 0
 		}
-		c.readOffset = 0
+		return
 	}
 
 	// read from conn
-	for ; offset < bLength; offset += c.readOffset {
-		_, err = io.ReadFull(c.Conn, c.readBuf)
-		if err != nil && err != io.EOF {
-			c.readOffset = 0
-			return offset, err
+	dataSize := 0
+	{ //read data size
+		c.readBuf = make([]byte, 2+c.aead.Overhead())
+		if _, err = io.ReadFull(c.Conn, c.readBuf); err != nil {
+			return
 		}
-
-		_, e := c.aead.Open(c.readBuf[:0], c.decryptNonce(), c.readBuf, nil)
-		if e != nil {
-			c.readOffset = 0
-			return offset, e
+		if _, err = c.aead.Open(c.readBuf[:0], c.decryptNonce(), c.readBuf, nil); err != nil {
+			return
 		}
-
-		c.readLast = int(c.readBuf[0])<<8 + int(c.readBuf[1]) + 2
-		c.readOffset = copy(b[offset:], c.readBuf[2:2+c.readLast])
-		if c.readOffset < c.readLast {
-			c.readOffset += 2
-			return len(b), nil
-		} else if err == io.EOF {
-			readOffset := c.readOffset
-			c.readOffset = 0
-			return readOffset, err
+		dataSize = int(c.readBuf[0])<<8 + int(c.readBuf[1])
+	}
+	{ // read data
+		c.readBuf = make([]byte, dataSize+c.aead.Overhead())
+		if _, err = io.ReadFull(c.Conn, c.readBuf); err != nil {
+			return
+		}
+		if _, err = c.aead.Open(c.readBuf[:0], c.decryptNonce(), c.readBuf, nil); err != nil {
+			return
 		}
 	}
-	return len(b), err
+
+	// buffer extra data
+	if n = copy(b, c.readBuf[:dataSize]); n < dataSize {
+		c.readOffset = n
+	}
+	return
 }
 
 func (c *conn) Write(b []byte) (n int, err error) {
-	bLength := len(b)
-	size := 0
+	bLen := len(b)
+	dataSize := MAX_SIZE - (2 + c.aead.Overhead()) - c.aead.Overhead()
+	if bLen < c.maxSize {
+		dataSize = bLen
+	}
 
-	for offset := 0; offset < bLength; offset += size {
-		if offset+c.dataSize <= bLength {
-			size = c.dataSize
-		} else {
-			size = bLength - offset
-		}
+	// BigEndian
+	c.writeBuf[0], c.writeBuf[1] = byte((dataSize&0xFF00)>>8), byte(dataSize&0xFF)
 
-		// BigEndian
-		c.writeBuf[0], c.writeBuf[1] = byte((size&0xFF00)>>8), byte(size&0xFF)
-		copy(c.writeBuf[2:size+2], b[offset:offset+size])
-		c.aead.Seal(c.writeBuf[:0], c.encryptNonce(), c.writeBuf[:c.dataSize+2], nil)
+	c.aead.Seal(c.writeBuf[:0], c.encryptNonce(), c.writeBuf[:2], nil)
+	c.aead.Seal(c.writeBuf[:2+c.aead.Overhead()], c.encryptNonce(), b[:dataSize], nil)
 
-		_, err = c.Conn.Write(c.writeBuf)
-		if err != nil {
-			return offset, err
-		}
+	_, err = c.Conn.Write(c.writeBuf[:dataSize+(2+c.aead.Overhead())+c.aead.Overhead()])
+	if err != nil {
+		return 0, err
 	}
 	return len(b), err
 }
@@ -115,12 +98,11 @@ func Shadow(c net.Conn, password string) (net.Conn, error) {
 	}
 
 	return &conn{
-		dataSize:     MTU - aead.Overhead() - 2,
+		maxSize:      MAX_SIZE - (2 - aead.Overhead()) - aead.Overhead(),
 		aead:         aead,
 		encryptNonce: newNonce(password, aead.NonceSize()),
 		decryptNonce: newNonce(password, aead.NonceSize()),
-		writeBuf:     make([]byte, MTU),
-		readBuf:      make([]byte, MTU),
+		writeBuf:     make([]byte, 0xFFFF),
 		Conn:         c,
 	}, nil
 }