add core

utils/ss/util.go

@@ -1,7 +1,11 @@
 package ss
 
 import (
+	"encoding/binary"
+	"fmt"
+	"io"
 	"net"
+	"strconv"
 
 	"github.com/snail007/goproxy/utils"
 )
@@ -26,3 +30,53 @@ const (
 	lenDmBase   = 2               // 1addrLen + 2port, plus addrLen
 	lenHmacSha1 = 10
 )
+
+func GetRequest(conn *Conn) (host string, err error) {
+
+	// buf size should at least have the same size with the largest possible
+	// request size (when addrType is 3, domain name has at most 256 bytes)
+	// 1(addrType) + 1(lenByte) + 255(max length address) + 2(port) + 10(hmac-sha1)
+	buf := make([]byte, 269)
+	// read till we get possible domain length field
+	if _, err = io.ReadFull(conn, buf[:idType+1]); err != nil {
+		return
+	}
+
+	var reqStart, reqEnd int
+	addrType := buf[idType]
+	switch addrType & AddrMask {
+	case typeIPv4:
+		reqStart, reqEnd = idIP0, idIP0+lenIPv4
+	case typeIPv6:
+		reqStart, reqEnd = idIP0, idIP0+lenIPv6
+	case typeDm:
+		if _, err = io.ReadFull(conn, buf[idType+1:idDmLen+1]); err != nil {
+			return
+		}
+		reqStart, reqEnd = idDm0, idDm0+int(buf[idDmLen])+lenDmBase
+	default:
+		err = fmt.Errorf("addr type %d not supported", addrType&AddrMask)
+		return
+	}
+
+	if _, err = io.ReadFull(conn, buf[reqStart:reqEnd]); err != nil {
+		return
+	}
+
+	// Return string for typeIP is not most efficient, but browsers (Chrome,
+	// Safari, Firefox) all seems using typeDm exclusively. So this is not a
+	// big problem.
+	switch addrType & AddrMask {
+	case typeIPv4:
+		host = net.IP(buf[idIP0 : idIP0+net.IPv4len]).String()
+	case typeIPv6:
+		host = net.IP(buf[idIP0 : idIP0+net.IPv6len]).String()
+	case typeDm:
+		host = string(buf[idDm0 : idDm0+int(buf[idDmLen])])
+	}
+	// parse port
+	port := binary.BigEndian.Uint16(buf[reqEnd-2 : reqEnd])
+	host = net.JoinHostPort(host, strconv.Itoa(int(port)))
+
+	return
+}