forked from fossabot/clash
/
proxy.go
347 lines (278 loc) · 8.47 KB
/
proxy.go
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package mitm
import (
"bufio"
"bytes"
"context"
"crypto/tls"
"encoding/pem"
"fmt"
"io"
"net"
"net/http"
"net/netip"
"os"
"strings"
"time"
"github.com/yaling888/clash/common/cache"
N "github.com/yaling888/clash/common/net"
"github.com/yaling888/clash/component/auth"
C "github.com/yaling888/clash/constant"
H "github.com/yaling888/clash/listener/http"
)
func HandleConn(c net.Conn, opt *C.MitmOption, in chan<- C.ConnContext, cache *cache.LruCache[string, bool], auth auth.Authenticator) {
var (
clientIP = netip.MustParseAddrPort(c.RemoteAddr().String()).Addr()
sourceAddr net.Addr
serverConn *N.BufferedConn
connState *tls.ConnectionState
)
defer func() {
if serverConn != nil {
_ = serverConn.Close()
}
}()
conn := N.NewBufferedConn(c)
trusted := cache == nil // disable authenticate if cache is nil
if !trusted {
trusted = clientIP.IsLoopback() || clientIP.IsUnspecified()
}
readLoop:
for {
// use SetReadDeadline instead of Proxy-Connection keep-alive
if err := conn.SetReadDeadline(time.Now().Add(65 * time.Second)); err != nil {
break
}
request, err := H.ReadRequest(conn.Reader())
if err != nil {
break
}
var response *http.Response
session := C.NewMitmSession(conn, request, response)
sourceAddr = parseSourceAddress(session.Request, conn.RemoteAddr(), sourceAddr)
session.Request.RemoteAddr = sourceAddr.String()
if !trusted {
session.Response = H.Authenticate(session.Request, cache, auth)
trusted = session.Response == nil
}
if trusted {
if session.Request.Method == http.MethodConnect {
if session.Request.ProtoMajor > 1 {
session.Request.ProtoMajor = 1
session.Request.ProtoMinor = 1
}
// Manual writing to support CONNECT for http 1.0 (workaround for uplay client)
if _, err = fmt.Fprintf(session.Conn, "HTTP/%d.%d %03d %s\r\n\r\n", session.Request.ProtoMajor, session.Request.ProtoMinor, http.StatusOK, "Connection established"); err != nil {
handleError(opt, session, err)
break // close connection
}
if strings.HasSuffix(session.Request.URL.Host, ":80") {
goto readLoop
}
b, err1 := conn.Peek(1)
if err1 != nil {
handleError(opt, session, err1)
break // close connection
}
// TLS handshake.
if b[0] == 0x16 {
tlsConn := tls.Server(conn, opt.CertConfig.NewTLSConfigForHost(session.Request.URL.Hostname()))
ctx, cancel := context.WithTimeout(context.Background(), C.DefaultTLSTimeout)
// handshake with the local client
if err = tlsConn.HandshakeContext(ctx); err != nil {
cancel()
session.Response = session.NewErrorResponse(fmt.Errorf("handshake failed: %w", err))
_ = writeResponse(session, false)
break // close connection
}
cancel()
cs := tlsConn.ConnectionState()
connState = &cs
conn = N.NewBufferedConn(tlsConn)
}
if strings.HasSuffix(session.Request.URL.Host, ":443") {
goto readLoop
}
if conn.SetReadDeadline(time.Now().Add(time.Second)) != nil {
break
}
buf, err2 := conn.Peek(7)
if err2 != nil {
if err2 != bufio.ErrBufferFull && !os.IsTimeout(err2) {
handleError(opt, session, err2)
break // close connection
}
}
// others protocol over tcp
if !isHTTPTraffic(buf) {
if connState != nil {
session.Request.TLS = connState
}
serverConn, err = getServerConn(serverConn, session.Request, sourceAddr, conn.LocalAddr(), in)
if err != nil {
break
}
if conn.SetReadDeadline(time.Time{}) != nil {
break
}
N.Relay(serverConn, conn)
return // hijack connection
}
goto readLoop
}
prepareRequest(connState, session.Request)
// hijack api
if session.Request.URL.Hostname() == opt.ApiHost {
if err = handleApiRequest(session, opt); err != nil {
handleError(opt, session, err)
}
break
}
// forward websocket
if isWebsocketRequest(request) {
serverConn, err = getServerConn(serverConn, session.Request, sourceAddr, conn.LocalAddr(), in)
if err != nil {
break
}
session.Request.RequestURI = ""
if session.Response = H.HandleUpgrade(conn, serverConn, request, in); session.Response == nil {
return // hijack connection
}
}
if session.Response == nil {
H.RemoveHopByHopHeaders(session.Request.Header)
H.RemoveExtraHTTPHostPort(session.Request)
// hijack custom request and write back custom response if necessary
newReq, newRes := opt.Handler.HandleRequest(session)
if newReq != nil {
session.Request = newReq
}
if newRes != nil {
session.Response = newRes
if err = writeResponse(session, false); err != nil {
handleError(opt, session, err)
break
}
continue
}
session.Request.RequestURI = ""
if session.Request.URL.Host == "" {
session.Response = session.NewErrorResponse(C.ErrInvalidURL)
} else {
serverConn, err = getServerConn(serverConn, session.Request, sourceAddr, conn.LocalAddr(), in)
if err != nil {
break
}
// send the request to remote server
err = session.Request.Write(serverConn)
if err != nil {
break
}
session.Response, err = http.ReadResponse(serverConn.Reader(), request)
if err != nil {
break
}
}
}
}
if err = writeResponseWithHandler(session, opt); err != nil {
handleError(opt, session, err)
break // close connection
}
}
_ = conn.Close()
}
func writeResponseWithHandler(session *C.MitmSession, opt *C.MitmOption) error {
res := opt.Handler.HandleResponse(session)
if res != nil {
session.Response = res
}
return writeResponse(session, true)
}
func writeResponse(session *C.MitmSession, keepAlive bool) error {
H.RemoveHopByHopHeaders(session.Response.Header)
if keepAlive {
session.Response.Header.Set("Connection", "keep-alive")
session.Response.Header.Set("Keep-Alive", "timeout=60")
}
return session.WriteResponse()
}
func handleApiRequest(session *C.MitmSession, opt *C.MitmOption) error {
if opt.CertConfig != nil && strings.ToLower(session.Request.URL.Path) == "/cert.crt" {
b := pem.EncodeToMemory(&pem.Block{
Type: "CERTIFICATE",
Bytes: opt.CertConfig.GetRootCA().Raw,
})
session.Response = session.NewResponse(http.StatusOK, bytes.NewReader(b))
session.Response.Close = true
session.Response.Header.Set("Content-Type", "application/x-x509-ca-cert")
session.Response.ContentLength = int64(len(b))
return session.WriteResponse()
}
b := `<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
<html><head>
<title>Clash MITM Proxy Services - 404 Not Found</title>
</head><body>
<h1>Not Found</h1>
<p>The requested URL %s was not found on this server.</p>
</body></html>
`
if opt.Handler.HandleApiRequest(session) {
return nil
}
b = fmt.Sprintf(b, session.Request.URL.Path)
session.Response = session.NewResponse(http.StatusNotFound, bytes.NewReader([]byte(b)))
session.Response.Close = true
session.Response.Header.Set("Content-Type", "text/html;charset=utf-8")
session.Response.ContentLength = int64(len(b))
return session.WriteResponse()
}
func handleError(opt *C.MitmOption, session *C.MitmSession, err error) {
if session.Response != nil {
defer func() {
_, _ = io.Copy(io.Discard, session.Response.Body)
_ = session.Response.Body.Close()
}()
}
opt.Handler.HandleError(session, err)
}
func prepareRequest(connState *tls.ConnectionState, request *http.Request) {
host := request.Header.Get("Host")
if host != "" {
request.Host = host
}
if request.URL.Host == "" {
request.URL.Host = request.Host
}
if request.URL.Scheme == "" {
request.URL.Scheme = "http"
}
if connState != nil {
request.TLS = connState
request.URL.Scheme = "https"
}
if request.Header.Get("Accept-Encoding") != "" {
request.Header.Set("Accept-Encoding", "gzip")
}
}
func parseSourceAddress(req *http.Request, connSource, source net.Addr) net.Addr {
if source != nil {
return source
}
sourceAddress := req.Header.Get("Origin-Request-Source-Address")
if sourceAddress == "" {
return connSource
}
req.Header.Del("Origin-Request-Source-Address")
addrPort, err := netip.ParseAddrPort(sourceAddress)
if err != nil {
return connSource
}
return net.TCPAddrFromAddrPort(addrPort)
}
func isWebsocketRequest(req *http.Request) bool {
return strings.EqualFold(req.Header.Get("Connection"), "Upgrade") && strings.EqualFold(req.Header.Get("Upgrade"), "websocket")
}
func isHTTPTraffic(buf []byte) bool {
method, _, _ := strings.Cut(string(buf), " ")
return validMethod(method)
}