Merge branch 'master' into dev

README.md

@@ -16,7 +16,7 @@ GoDoc at https://godoc.org/github.com/shadowsocks/go-shadowsocks2/
 ## Install
 
 ```sh
-go get github.com/shadowsocks/go-shadowsocks2
+go get -u -v github.com/riobard/go-shadowsocks2
 ```
 
 

core/cipher.go

@@ -0,0 +1,134 @@
+package core
+
+import (
+	"crypto/md5"
+	"errors"
+	"net"
+	"sort"
+	"strings"
+
+	"github.com/riobard/go-shadowsocks2/shadowaead"
+	"github.com/riobard/go-shadowsocks2/shadowstream"
+)
+
+type Cipher interface {
+	StreamConnCipher
+	PacketConnCipher
+}
+
+type StreamConnCipher interface {
+	StreamConn(net.Conn) net.Conn
+}
+
+type PacketConnCipher interface {
+	PacketConn(net.PacketConn) net.PacketConn
+}
+
+// ErrCipherNotSupported occurs when a cipher is not supported (likely because of security concerns).
+var ErrCipherNotSupported = errors.New("cipher not supported")
+
+// List of AEAD ciphers: key size in bytes and constructor
+var aeadList = map[string]struct {
+	KeySize int
+	New     func([]byte) (shadowaead.Cipher, error)
+}{
+	"aes-128-gcm":            {16, shadowaead.AESGCM},
+	"aes-192-gcm":            {24, shadowaead.AESGCM},
+	"aes-256-gcm":            {32, shadowaead.AESGCM},
+	"chacha20-ietf-poly1305": {32, shadowaead.Chacha20IETFPoly1305},
+}
+
+// List of stream ciphers: key size in bytes and constructor
+var streamList = map[string]struct {
+	KeySize int
+	New     func(key []byte) (shadowstream.Cipher, error)
+}{
+	"aes-128-ctr":   {16, shadowstream.AESCTR},
+	"aes-192-ctr":   {24, shadowstream.AESCTR},
+	"aes-256-ctr":   {32, shadowstream.AESCTR},
+	"aes-128-cfb":   {16, shadowstream.AESCFB},
+	"aes-192-cfb":   {24, shadowstream.AESCFB},
+	"aes-256-cfb":   {32, shadowstream.AESCFB},
+	"chacha20-ietf": {32, shadowstream.Chacha20IETF},
+}
+
+// ListCipher returns a list of available cipher names sorted alphabetically.
+func ListCipher() []string {
+	var l []string
+	for k := range aeadList {
+		l = append(l, k)
+	}
+	for k := range streamList {
+		l = append(l, k)
+	}
+	sort.Strings(l)
+	return l
+}
+
+// PickCipher returns a Cipher of the given name. Derive key from password if given key is empty.
+func PickCipher(name string, key []byte, password string) (Cipher, error) {
+	name = strings.ToLower(name)
+
+	if name == "dummy" {
+		return &dummy{}, nil
+	}
+
+	if choice, ok := aeadList[name]; ok {
+		if len(key) == 0 {
+			key = kdf(password, choice.KeySize)
+		}
+		if len(key) != choice.KeySize {
+			return nil, shadowaead.KeySizeError(choice.KeySize)
+		}
+		aead, err := choice.New(key)
+		return &aeadCipher{aead}, err
+	}
+
+	if choice, ok := streamList[name]; ok {
+		if len(key) == 0 {
+			key = kdf(password, choice.KeySize)
+		}
+		if len(key) != choice.KeySize {
+			return nil, shadowstream.KeySizeError(choice.KeySize)
+		}
+		ciph, err := choice.New(key)
+		return &streamCipher{ciph}, err
+	}
+
+	return nil, ErrCipherNotSupported
+}
+
+type aeadCipher struct{ shadowaead.Cipher }
+
+func (aead *aeadCipher) StreamConn(c net.Conn) net.Conn { return shadowaead.NewConn(c, aead) }
+func (aead *aeadCipher) PacketConn(c net.PacketConn) net.PacketConn {
+	return shadowaead.NewPacketConn(c, aead)
+}
+
+type streamCipher struct{ shadowstream.Cipher }
+
+func (ciph *streamCipher) StreamConn(c net.Conn) net.Conn { return shadowstream.NewConn(c, ciph) }
+func (ciph *streamCipher) PacketConn(c net.PacketConn) net.PacketConn {
+	return shadowstream.NewPacketConn(c, ciph)
+}
+
+// dummy cipher does not encrypt
+
+type dummy struct{}
+
+func (dummy) StreamConn(c net.Conn) net.Conn             { return c }
+func (dummy) PacketConn(c net.PacketConn) net.PacketConn { return c }
+
+// key-derivation function from original Shadowsocks
+func kdf(password string, keyLen int) []byte {
+	var b, prev []byte
+	h := md5.New()
+	for len(b) < keyLen {
+		h.Write(prev)
+		h.Write([]byte(password))
+		b = h.Sum(b)
+		prev = b[len(b)-h.Size():]
+		h.Reset()
+	}
+	return b[:keyLen]
+}

core/doc.go

@@ -1,2 +1,2 @@
-// Package core provides essential interfaces for Shadowsocks
+// Package core implements essential parts of Shadowsocks
 package core

core/packet.go

@@ -2,9 +2,7 @@ package core
 
 import "net"
 
-type PacketConnCipher func(net.PacketConn) net.PacketConn
-
 func ListenPacket(network, address string, ciph PacketConnCipher) (net.PacketConn, error) {
 	c, err := net.ListenPacket(network, address)
-	return ciph(c), err
+	return ciph.PacketConn(c), err
 }

core/stream.go

@@ -2,8 +2,6 @@ package core
 
 import "net"
 
-type StreamConnCipher func(net.Conn) net.Conn
-
 type listener struct {
 	net.Listener
 	StreamConnCipher
@@ -16,10 +14,10 @@ func Listen(network, address string, ciph StreamConnCipher) (net.Listener, error
 
 func (l *listener) Accept() (net.Conn, error) {
 	c, err := l.Listener.Accept()
-	return l.StreamConnCipher(c), err
+	return l.StreamConn(c), err
 }
 
 func Dial(network, address string, ciph StreamConnCipher) (net.Conn, error) {
 	c, err := net.Dial(network, address)
-	return ciph(c), err
+	return ciph.StreamConn(c), err
 }