add pac auto config and auto download functions

fly/cipher.go

@@ -23,7 +23,7 @@ var (
 	IV = []byte{0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f}
 )
 
-var cipherMap = map[string]*cipherEntity{
+var CipherMap = map[string]*cipherEntity{
 	"aes-128-cfb":   {16, 16, newAESCFBStream},
 	"aes-192-cfb":   {24, 16, newAESCFBStream},
 	"aes-256-cfb":   {32, 16, newAESCFBStream},
@@ -74,12 +74,9 @@ func NewCipherInstance(secretKey, method string) *Cipher {
 	if secretKey == "" {
 		secretKey = key
 	}
-	entity := cipherMap[method]
+	entity := CipherMap[method]
 	if entity == nil {
-		entity = cipherMap["aes-256-cfb"]
-		logger.Println("encrypt method: aes-256-cfb")
-	}else {
-		logger.Println("encrypt method:", method)
+		entity = CipherMap["aes-256-cfb"]
 	}
 
 	key := genKey(secretKey, entity.keyLen)

fly/pac.go

@@ -7,24 +7,60 @@ import (
 	"os"
 )
 
-func StartPAC() {
-	http.HandleFunc("/flynet.pac", func (w http.ResponseWriter, r *http.Request){
-		// the pac file should be placed at the same dir with current running file.
-		// but it is placed at the parent dir when development
-		file, err := os.Open(`flynet.pac`)
+// return the stream and size of pac file
+func GetPAC() ([]byte, int) {
+	// run from the same dir with flynet.pac
+	file, err := os.Open(`flynet.pac`)
+	if err != nil {
+		// run from cmd/client/client.go
+		file, err = os.Open("../../flynet.pac")
+		if err != nil {
+			// run from fly/pac_test.go
+			file, err = os.Open("../flynet.pac")
+			if err != nil {
+				logger.Println("pac file not found! start downlaod from github...")
+				err := downloadPAC()
+				logger.Println("pac file download completed!")
+				if err != nil {
+					return nil, 0
+				}
+				return GetPAC()
+			}
+		}
+	}
+
+	index := 0
+	fileBuff := make([]byte, 200*1024)
+	for {
+		logger.Println("start reading...")
+		n, err := file.Read(fileBuff[index:])
 		if err != nil {
-			fmt.Println(err)
-			// run from cmd/client/
-			file, _ = os.Open("../flynet.pac")
-			//file, _ = os.Open("../../flynet.pac")
+			if err == io.EOF {
+				logger.Println("read pac file ok.")
+				break
+			}
+			logger.Println("read pac file error --->", err)
 		}
-		w.Header().Set("Content-Type", "application/x-ns-proxy-autoconfig")
-		io.Copy(w, file)
-		w.WriteHeader(200)
+		index += n
+	}
+	return fileBuff, index
+}
+
+func downloadPAC() error {
+	fileName := "flynet.pac"
+	resp, err := http.Get("https://raw.githubusercontent.com/petronny/gfwlist2pac/master/gfwlist.pac")
+	if err != nil {
+		logger.Println("download pac file failed --->", err)
+		logger.Panicln("please check your network or disable pac mode!")
+		return err
+	}
+	defer resp.Body.Close()
 
-	})
-	err := http.ListenAndServe(":8080", nil)
+	file, err := os.Create(fileName)
 	if err != nil {
-		fmt.Println("start failed --->", err)
+		logger.Println("create pac file failed --->", err)
+		return err
 	}
+	io.Copy(file, resp.Body)
+	return nil
 }

fly/relay.go

@@ -1,7 +1,6 @@
 package fly
 
 import (
-	"fmt"
 	"github.com/xtaci/kcp-go"
 	"io"
 	"net"

fly/socks5.go

@@ -1,6 +1,7 @@
 package fly
 
 import (
+	"bytes"
 	"crypto/sha1"
 	"fmt"
 	"github.com/xtaci/kcp-go"
@@ -72,6 +73,13 @@ func handleClient(client net.Conn) {
 
 func Socks5ForClientByTCP(localPort, serverAddr, method, key string) {
 	listener := ListenTCP(localPort)
+
+	cipherEntity := CipherMap[method]
+	if cipherEntity == nil {
+		logger.Println("encrypt method: aes-256-cfb")
+	}else {
+		logger.Println("encrypt method:", method)
+	}
 	for {
 		client, err := listener.Accept()
 		if err != nil {
@@ -119,13 +127,22 @@ func Socks5ForClientByTCP(localPort, serverAddr, method, key string) {
 
 				go RelayTraffic(server, client)
 				RelayTraffic(client, server)
+			}else {
+				handlePACRequest(client, buff[:n], localPort)
 			}
 		}()
 	}
 }
 
 func Socks5ForServerByTCP(localPort, method, key string) {
 	listener := ListenTCP(localPort)
+
+	cipherEntity := CipherMap[method]
+	if cipherEntity == nil {
+		logger.Println("encrypt method: aes-256-cfb")
+	}else {
+		logger.Println("encrypt method:", method)
+	}
 	for {
 		logger.Println("waiting...")
 		client, err := listener.Accept()
@@ -140,14 +157,14 @@ func Socks5ForServerByTCP(localPort, method, key string) {
 			if err != nil {
 				logger.Println("read target address failed --->", err)
 				return
-			}else if n < 7 {
+			} else if n < 7 {
 				logger.Println("read error of request length --->", buff[:n])
 				return
 			}
 
 			host, port := parseSocksRequest(buff[:n], n)
 			//logger.Printf("target server ------\n%s:%s\n------\n%d\n+++++++\n", host, port, buff[:n])
-			logger.Printf("target server ---> %s:%s <---\n", host, port)
+			logger.Printf("target server: %s:%s\n", host, port)
 
 			// dial the target server
 			server, err := net.Dial("tcp", net.JoinHostPort(host, port))
@@ -216,7 +233,7 @@ func Socks5ForServerByUDP(localPort string) {
 				if err != nil {
 					logger.Println("read target address failed --->", err)
 					return
-				}else if n < 7 {
+				} else if n < 7 {
 					logger.Println("read error of request length --->", data[:n])
 					return
 				}
@@ -276,3 +293,22 @@ func parseSocksRequest(data []byte, n int) (string, string) {
 	port = strconv.Itoa(int(p1)<<8 | int(p2))
 	return host, port
 }
+
+func handlePACRequest(conn net.Conn, buff []byte, port string)  {
+	if bytes.Contains(buff[:], []byte("flynet.pac HTTP")) {
+		fileBuff, size := GetPAC()
+		// replace the socks5 port of pac file with the port user choose
+		fileBuff = bytes.Replace(fileBuff[:size], []byte("SOCKS5 127.0.0.1:1080"), []byte("SOCKS5 127.0.0.1:" + port), 1)
+
+		_, _ = conn.Write([]byte(fmt.Sprintf("HTTP/1.1 200 OK\r\n"+
+			"Content-Type: application/x-ns-proxy-autoconfig\r\n"+
+			"Server: flynet\r\nContent-Length: %d\r\n\r\n", size)))
+		_, _ = conn.Write(fileBuff[:size])
+	}else {
+		msg := "hello,flynet!"
+		_, _ = conn.Write([]byte(fmt.Sprintf("HTTP/1.1 200 OK\r\n"+
+			"Content-Type: text/html; charset=utf-8\r\n"+
+			"Server: flynet\r\nContent-Length: %d\r\n\r\n%s", len(msg), msg)))
+	}
+	conn.Close()
+}

flynet.conf

@@ -10,20 +10,25 @@
 # more information at https://github.com/asche910/flynet
 #
 
+# if you use flynet in server side, you just care about the the attributes below [server]
 [server]
 mode = socks5-tcp # work mode
 port = 8888     # listen port; multi port use space to divide
-method = "aes-256-cfb"
+method = aes-256-cfb
 password =
 verbose = true
 log = flynet.log
 
 
+# if you use flynet in client side, you just care about the the attributes below [client]
 [client]
 mode = socks5-tcp # work mode
 port = 1080 # local socks5 listen port
-serverAddr = example.com:8080 # include host and port
-method = "aes-256-cfb"
+serverAddr = example.com:8888 # include host and port
+method = aes-256-cfb
 password =
+pac-on = true # if true, flynet will start pac mode, and listen at 'http://localhost:pac-port/flynet.pac'(default pac-port is 2080)
+pac-port = 2080
+pac-update = false # if true, flynet will download the latest pac file from github
 verbose = false
-# log = flynet.log
+# log = flynet.log