improve ss

pkg/handler/http/handler.go

@@ -0,0 +1,404 @@
+package http
+
+import (
+	"bufio"
+	"bytes"
+	"context"
+	"encoding/base64"
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"hash/crc32"
+	"net"
+	"net/http"
+	"net/http/httputil"
+	"os"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/go-gost/gost/pkg/auth"
+	"github.com/go-gost/gost/pkg/bypass"
+	"github.com/go-gost/gost/pkg/chain"
+	"github.com/go-gost/gost/pkg/handler"
+	"github.com/go-gost/gost/pkg/logger"
+	md "github.com/go-gost/gost/pkg/metadata"
+	"github.com/go-gost/gost/pkg/registry"
+)
+
+func init() {
+	registry.RegisterHandler("http", NewHandler)
+}
+
+type httpHandler struct {
+	chain  *chain.Chain
+	bypass bypass.Bypass
+	logger logger.Logger
+	md     metadata
+}
+
+func NewHandler(opts ...handler.Option) handler.Handler {
+	options := &handler.Options{}
+	for _, opt := range opts {
+		opt(options)
+	}
+
+	return &httpHandler{
+		chain:  options.Chain,
+		bypass: options.Bypass,
+		logger: options.Logger,
+	}
+}
+
+func (h *httpHandler) Init(md md.Metadata) error {
+	return h.parseMetadata(md)
+}
+
+func (h *httpHandler) parseMetadata(md md.Metadata) error {
+	h.md.proxyAgent = md.GetString(proxyAgentKey)
+
+	if v, _ := md.Get(authsKey).([]interface{}); len(v) > 0 {
+		authenticator := auth.NewLocalAuthenticator(nil)
+		for _, auth := range v {
+			if s, _ := auth.(string); s != "" {
+				ss := strings.SplitN(s, ":", 2)
+				if len(ss) == 1 {
+					authenticator.Add(ss[0], "")
+				} else {
+					authenticator.Add(ss[0], ss[1])
+				}
+			}
+		}
+		h.md.authenticator = authenticator
+	}
+
+	if v := md.GetString(probeResistKey); v != "" {
+		if ss := strings.SplitN(v, ":", 2); len(ss) == 2 {
+			h.md.probeResist = &probeResist{
+				Type:  ss[0],
+				Value: ss[1],
+				Knock: md.GetString(knockKey),
+			}
+		}
+	}
+	h.md.retryCount = md.GetInt(retryCount)
+
+	return nil
+}
+
+func (h *httpHandler) Handle(ctx context.Context, conn net.Conn) {
+	defer conn.Close()
+
+	start := time.Now()
+
+	h.logger = h.logger.WithFields(map[string]interface{}{
+		"remote": conn.RemoteAddr().String(),
+		"local":  conn.LocalAddr().String(),
+	})
+
+	h.logger.Infof("%s <> %s", conn.RemoteAddr(), conn.LocalAddr())
+	defer func() {
+		h.logger.WithFields(map[string]interface{}{
+			"duration": time.Since(start),
+		}).Infof("%s >< %s", conn.RemoteAddr(), conn.LocalAddr())
+	}()
+
+	req, err := http.ReadRequest(bufio.NewReader(conn))
+	if err != nil {
+		h.logger.Error(err)
+		return
+	}
+	defer req.Body.Close()
+
+	h.handleRequest(ctx, conn, req)
+}
+
+func (h *httpHandler) handleRequest(ctx context.Context, conn net.Conn, req *http.Request) {
+	if req == nil {
+		return
+	}
+
+	// Try to get the actual host.
+	// Compatible with GOST 2.x.
+	if v := req.Header.Get("Gost-Target"); v != "" {
+		if h, err := h.decodeServerName(v); err == nil {
+			req.Host = h
+		}
+	}
+	req.Header.Del("Gost-Target")
+
+	if v := req.Header.Get("X-Gost-Target"); v != "" {
+		if h, err := h.decodeServerName(v); err == nil {
+			req.Host = h
+		}
+	}
+	req.Header.Del("X-Gost-Target")
+
+	host := req.Host
+	if _, port, _ := net.SplitHostPort(host); port == "" {
+		host = net.JoinHostPort(host, "80")
+	}
+
+	fields := map[string]interface{}{
+		"dst": host,
+	}
+	if u, _, _ := h.basicProxyAuth(req.Header.Get("Proxy-Authorization")); u != "" {
+		fields["user"] = u
+	}
+	h.logger = h.logger.WithFields(fields)
+
+	if h.logger.IsLevelEnabled(logger.DebugLevel) {
+		dump, _ := httputil.DumpRequest(req, false)
+		h.logger.Debug(string(dump))
+	}
+	h.logger.Infof("%s > %s", conn.RemoteAddr(), host)
+
+	resp := &http.Response{
+		ProtoMajor: 1,
+		ProtoMinor: 1,
+		Header:     http.Header{},
+	}
+
+	if h.md.proxyAgent != "" {
+		resp.Header.Add("Proxy-Agent", h.md.proxyAgent)
+	}
+
+	/*
+		if !Can("tcp", host, h.options.Whitelist, h.options.Blacklist) {
+			log.Logf("[http] %s - %s : Unauthorized to tcp connect to %s",
+				conn.RemoteAddr(), conn.LocalAddr(), host)
+			resp.StatusCode = http.StatusForbidden
+
+			if Debug {
+				dump, _ := httputil.DumpResponse(resp, false)
+				log.Logf("[http] %s <- %s\n%s", conn.RemoteAddr(), conn.LocalAddr(), string(dump))
+			}
+
+			resp.Write(conn)
+			return
+		}
+	*/
+
+	if h.bypass != nil && h.bypass.Contains(host) {
+		resp.StatusCode = http.StatusForbidden
+
+		if h.logger.IsLevelEnabled(logger.DebugLevel) {
+			dump, _ := httputil.DumpResponse(resp, false)
+			h.logger.Debug(string(dump))
+		}
+		h.logger.Info("bypass: ", host)
+
+		resp.Write(conn)
+		return
+	}
+
+	if !h.authenticate(conn, req, resp) {
+		return
+	}
+
+	if req.Method == "PRI" ||
+		(req.Method != http.MethodConnect && req.URL.Scheme != "http") {
+		resp.StatusCode = http.StatusBadRequest
+		resp.Write(conn)
+
+		if h.logger.IsLevelEnabled(logger.DebugLevel) {
+			dump, _ := httputil.DumpResponse(resp, false)
+			h.logger.Debug(string(dump))
+		}
+
+		return
+	}
+
+	req.Header.Del("Proxy-Authorization")
+
+	cc, err := h.dial(ctx, host)
+	if err != nil {
+		resp.StatusCode = http.StatusServiceUnavailable
+		resp.Write(conn)
+
+		if h.logger.IsLevelEnabled(logger.DebugLevel) {
+			dump, _ := httputil.DumpResponse(resp, false)
+			h.logger.Debug(string(dump))
+		}
+		return
+	}
+	defer cc.Close()
+
+	if req.Method == http.MethodConnect {
+		resp.StatusCode = http.StatusOK
+		resp.Status = "200 Connection established"
+
+		if h.logger.IsLevelEnabled(logger.DebugLevel) {
+			dump, _ := httputil.DumpResponse(resp, false)
+			h.logger.Debug(string(dump))
+		}
+		if err = resp.Write(conn); err != nil {
+			h.logger.Warn(err)
+			return
+		}
+	} else {
+		req.Header.Del("Proxy-Connection")
+		if err = req.Write(cc); err != nil {
+			h.logger.Warn(err)
+			return
+		}
+	}
+
+	h.logger.Infof("%s <> %s", conn.RemoteAddr(), host)
+	handler.Transport(conn, cc)
+	h.logger.Infof("%s >< %s", conn.RemoteAddr(), host)
+}
+
+func (h *httpHandler) dial(ctx context.Context, addr string) (conn net.Conn, err error) {
+	count := h.md.retryCount + 1
+	if count <= 0 {
+		count = 1
+	}
+
+	for i := 0; i < count; i++ {
+		route := h.chain.GetRouteFor(addr)
+
+		if h.logger.IsLevelEnabled(logger.DebugLevel) {
+			buf := bytes.Buffer{}
+			for _, node := range route.Path() {
+				fmt.Fprintf(&buf, "%s@%s > ", node.Name(), node.Addr())
+			}
+			fmt.Fprintf(&buf, "%s", addr)
+			h.logger.Debugf("route(retry=%d): %s", i, buf.String())
+		}
+
+		/*
+			// forward http request
+			lastNode := route.LastNode()
+			if req.Method != http.MethodConnect && lastNode.Protocol == "http" {
+				err = h.forwardRequest(conn, req, route)
+				if err == nil {
+					return
+				}
+				log.Logf("[http] %s -> %s : %s", conn.RemoteAddr(), conn.LocalAddr(), err)
+				continue
+			}
+		*/
+
+		conn, err = route.Dial(ctx, "tcp", addr)
+		if err == nil {
+			break
+		}
+		h.logger.Errorf("route(retry=%d): %s", i, err)
+	}
+
+	return
+}
+
+func (h *httpHandler) decodeServerName(s string) (string, error) {
+	b, err := base64.RawURLEncoding.DecodeString(s)
+	if err != nil {
+		return "", err
+	}
+	if len(b) < 4 {
+		return "", errors.New("invalid name")
+	}
+	v, err := base64.RawURLEncoding.DecodeString(string(b[4:]))
+	if err != nil {
+		return "", err
+	}
+	if crc32.ChecksumIEEE(v) != binary.BigEndian.Uint32(b[:4]) {
+		return "", errors.New("invalid name")
+	}
+	return string(v), nil
+}
+
+func (h *httpHandler) basicProxyAuth(proxyAuth string) (username, password string, ok bool) {
+	if proxyAuth == "" {
+		return
+	}
+
+	if !strings.HasPrefix(proxyAuth, "Basic ") {
+		return
+	}
+	c, err := base64.StdEncoding.DecodeString(strings.TrimPrefix(proxyAuth, "Basic "))
+	if err != nil {
+		return
+	}
+	cs := string(c)
+	s := strings.IndexByte(cs, ':')
+	if s < 0 {
+		return
+	}
+
+	return cs[:s], cs[s+1:], true
+}
+
+func (h *httpHandler) authenticate(conn net.Conn, req *http.Request, resp *http.Response) (ok bool) {
+	u, p, _ := h.basicProxyAuth(req.Header.Get("Proxy-Authorization"))
+	if h.md.authenticator == nil || h.md.authenticator.Authenticate(u, p) {
+		return true
+	}
+
+	pr := h.md.probeResist
+	// probing resistance is enabled, and knocking host is mismatch.
+	if pr != nil && (pr.Knock == "" || !strings.EqualFold(req.URL.Hostname(), pr.Knock)) {
+		resp.StatusCode = http.StatusServiceUnavailable // default status code
+
+		switch pr.Type {
+		case "code":
+			resp.StatusCode, _ = strconv.Atoi(pr.Value)
+		case "web":
+			url := pr.Value
+			if !strings.HasPrefix(url, "http") {
+				url = "http://" + url
+			}
+			if r, err := http.Get(url); err == nil {
+				resp = r
+				defer r.Body.Close()
+			}
+		case "host":
+			cc, err := net.Dial("tcp", pr.Value)
+			if err == nil {
+				defer cc.Close()
+
+				req.Write(cc)
+				handler.Transport(conn, cc)
+				return
+			}
+		case "file":
+			f, _ := os.Open(pr.Value)
+			if f != nil {
+				resp.StatusCode = http.StatusOK
+				if finfo, _ := f.Stat(); finfo != nil {
+					resp.ContentLength = finfo.Size()
+				}
+				resp.Header.Set("Content-Type", "text/html")
+				resp.Body = f
+			}
+		}
+	}
+
+	if resp.StatusCode == 0 {
+		resp.StatusCode = http.StatusProxyAuthRequired
+		resp.Header.Add("Proxy-Authenticate", "Basic realm=\"gost\"")
+		if strings.ToLower(req.Header.Get("Proxy-Connection")) == "keep-alive" {
+			// XXX libcurl will keep sending auth request in same conn
+			// which we don't supported yet.
+			resp.Header.Add("Connection", "close")
+			resp.Header.Add("Proxy-Connection", "close")
+		}
+
+		h.logger.Info("proxy authentication required")
+	} else {
+		resp.Header = http.Header{}
+		resp.Header.Set("Server", "nginx/1.20.1")
+		resp.Header.Set("Date", time.Now().Format(http.TimeFormat))
+		if resp.StatusCode == http.StatusOK {
+			resp.Header.Set("Connection", "keep-alive")
+		}
+	}
+
+	if h.logger.IsLevelEnabled(logger.DebugLevel) {
+		dump, _ := httputil.DumpResponse(resp, false)
+		h.logger.Debug(string(dump))
+	}
+
+	resp.Write(conn)
+	return
+}