plugin: add http_proxy

models/plugin/http_proxy.go

@@ -0,0 +1,226 @@
+// Copyright 2017 frp team
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package plugin
+
+import (
+	"encoding/base64"
+	"fmt"
+	"io"
+	"net"
+	"net/http"
+	"strings"
+	"sync"
+
+	"github.com/fatedier/frp/models/proto/tcp"
+	"github.com/fatedier/frp/utils/errors"
+	frpNet "github.com/fatedier/frp/utils/net"
+)
+
+const PluginHttpProxy = "http_proxy"
+
+func init() {
+	Register(PluginHttpProxy, NewHttpProxyPlugin)
+}
+
+type Listener struct {
+	conns  chan net.Conn
+	closed bool
+	mu     sync.Mutex
+}
+
+func NewProxyListener() *Listener {
+	return &Listener{
+		conns: make(chan net.Conn, 64),
+	}
+}
+
+func (l *Listener) Accept() (net.Conn, error) {
+	conn, ok := <-l.conns
+	if !ok {
+		return nil, fmt.Errorf("listener closed")
+	}
+	return conn, nil
+}
+
+func (l *Listener) PutConn(conn net.Conn) error {
+	err := errors.PanicToError(func() {
+		l.conns <- conn
+	})
+	return err
+}
+
+func (l *Listener) Close() error {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	if !l.closed {
+		close(l.conns)
+	}
+	return nil
+}
+
+func (l *Listener) Addr() net.Addr {
+	return (*net.TCPAddr)(nil)
+}
+
+type HttpProxy struct {
+	l          *Listener
+	s          *http.Server
+	AuthUser   string
+	AuthPasswd string
+}
+
+func NewHttpProxyPlugin(params map[string]string) (Plugin, error) {
+	user := params["plugin_http_user"]
+	passwd := params["plugin_http_passwd"]
+	listener := NewProxyListener()
+
+	hp := &HttpProxy{
+		l:          listener,
+		AuthUser:   user,
+		AuthPasswd: passwd,
+	}
+
+	hp.s = &http.Server{
+		Handler: hp,
+	}
+
+	go hp.s.Serve(listener)
+	return hp, nil
+}
+
+func (hp *HttpProxy) Name() string {
+	return PluginHttpProxy
+}
+
+func (hp *HttpProxy) Handle(conn io.ReadWriteCloser) {
+	var wrapConn net.Conn
+	if realConn, ok := conn.(net.Conn); ok {
+		wrapConn = realConn
+	} else {
+		wrapConn = frpNet.WrapReadWriteCloserToConn(conn)
+	}
+
+	hp.l.PutConn(wrapConn)
+	return
+}
+
+func (hp *HttpProxy) Close() error {
+	hp.s.Close()
+	hp.l.Close()
+	return nil
+}
+
+func (hp *HttpProxy) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
+	if ok := hp.Auth(rw, req); !ok {
+		rw.Header().Set("Proxy-Authenticate", "Basic")
+		rw.WriteHeader(http.StatusProxyAuthRequired)
+		return
+	}
+
+	if req.Method == "CONNECT" {
+		hp.ConnectHandler(rw, req)
+	} else {
+		hp.HttpHandler(rw, req)
+	}
+}
+
+func (hp *HttpProxy) HttpHandler(rw http.ResponseWriter, req *http.Request) {
+	removeProxyHeaders(req)
+
+	resp, err := http.DefaultTransport.RoundTrip(req)
+	if err != nil {
+		http.Error(rw, err.Error(), http.StatusInternalServerError)
+		return
+	}
+	defer resp.Body.Close()
+
+	copyHeaders(rw.Header(), resp.Header)
+	rw.WriteHeader(resp.StatusCode)
+
+	_, err = io.Copy(rw, resp.Body)
+	if err != nil && err != io.EOF {
+		return
+	}
+}
+
+func (hp *HttpProxy) ConnectHandler(rw http.ResponseWriter, req *http.Request) {
+	hj, ok := rw.(http.Hijacker)
+	if !ok {
+		rw.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+
+	client, _, err := hj.Hijack()
+	if err != nil {
+		rw.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+
+	remote, err := net.Dial("tcp", req.URL.Host)
+	if err != nil {
+		http.Error(rw, "Failed", http.StatusBadRequest)
+		client.Close()
+		return
+	}
+	client.Write([]byte("HTTP/1.0 200 OK\r\n\r\n"))
+
+	go tcp.Join(remote, client)
+}
+
+func (hp *HttpProxy) Auth(rw http.ResponseWriter, req *http.Request) bool {
+	if hp.AuthUser == "" && hp.AuthPasswd == "" {
+		return true
+	}
+
+	s := strings.SplitN(req.Header.Get("Proxy-Authorization"), " ", 2)
+	if len(s) != 2 {
+		return false
+	}
+
+	b, err := base64.StdEncoding.DecodeString(s[1])
+	if err != nil {
+		return false
+	}
+
+	pair := strings.SplitN(string(b), ":", 2)
+	if len(pair) != 2 {
+		return false
+	}
+
+	if pair[0] != hp.AuthUser || pair[1] != hp.AuthPasswd {
+		return false
+	}
+	return true
+}
+
+func copyHeaders(dst, src http.Header) {
+	for key, values := range src {
+		for _, value := range values {
+			dst.Add(key, value)
+		}
+	}
+}
+
+func removeProxyHeaders(req *http.Request) {
+	req.RequestURI = ""
+	req.Header.Del("Proxy-Connection")
+	req.Header.Del("Connection")
+	req.Header.Del("Proxy-Authenticate")
+	req.Header.Del("Proxy-Authorization")
+	req.Header.Del("TE")
+	req.Header.Del("Trailers")
+	req.Header.Del("Transfer-Encoding")
+	req.Header.Del("Upgrade")
+}