145 lines
2.6 KiB
Go
145 lines
2.6 KiB
Go
package http
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import (
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"bufio"
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"bytes"
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"crypto/rand"
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"encoding/base64"
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"io"
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"net"
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"net/http"
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"net/http/httputil"
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"net/url"
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"sync"
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"github.com/go-gost/gost/v3/pkg/logger"
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)
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type obfsHTTPConn struct {
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net.Conn
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host string
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rbuf bytes.Buffer
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wbuf bytes.Buffer
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headerDrained bool
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handshaked bool
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handshakeMutex sync.Mutex
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header http.Header
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logger logger.Logger
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}
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func (c *obfsHTTPConn) Handshake() (err error) {
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c.handshakeMutex.Lock()
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defer c.handshakeMutex.Unlock()
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if c.handshaked {
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return nil
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}
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err = c.handshake()
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if err != nil {
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return
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}
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c.handshaked = true
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return nil
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}
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func (c *obfsHTTPConn) handshake() (err error) {
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r := &http.Request{
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Method: http.MethodGet,
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ProtoMajor: 1,
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ProtoMinor: 1,
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URL: &url.URL{Scheme: "http", Host: c.host},
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Header: c.header,
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}
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if r.Header == nil {
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r.Header = http.Header{}
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}
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r.Header.Set("Connection", "Upgrade")
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r.Header.Set("Upgrade", "websocket")
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key, _ := c.generateChallengeKey()
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r.Header.Set("Sec-WebSocket-Key", key)
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// cache the request header
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if err = r.Write(&c.wbuf); err != nil {
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return
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}
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if c.logger.IsLevelEnabled(logger.DebugLevel) {
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dump, _ := httputil.DumpRequest(r, false)
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c.logger.Debug(string(dump))
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}
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return nil
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}
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func (c *obfsHTTPConn) Read(b []byte) (n int, err error) {
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if err = c.Handshake(); err != nil {
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return
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}
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if err = c.drainHeader(); err != nil {
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return
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}
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if c.rbuf.Len() > 0 {
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return c.rbuf.Read(b)
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}
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return c.Conn.Read(b)
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}
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func (c *obfsHTTPConn) drainHeader() (err error) {
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if c.headerDrained {
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return
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}
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c.headerDrained = true
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br := bufio.NewReader(c.Conn)
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// drain and discard the response header
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var line string
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var buf bytes.Buffer
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for {
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line, err = br.ReadString('\n')
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if err != nil {
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return
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}
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buf.WriteString(line)
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if line == "\r\n" {
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break
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}
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}
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if c.logger.IsLevelEnabled(logger.DebugLevel) {
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c.logger.Debug(buf.String())
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}
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// cache the extra data for next read.
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var b []byte
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b, err = br.Peek(br.Buffered())
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if len(b) > 0 {
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_, err = c.rbuf.Write(b)
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}
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return
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}
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func (c *obfsHTTPConn) Write(b []byte) (n int, err error) {
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if err = c.Handshake(); err != nil {
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return
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}
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if c.wbuf.Len() > 0 {
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c.wbuf.Write(b) // append the data to the cached header
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_, err = c.wbuf.WriteTo(c.Conn)
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n = len(b) // exclude the header length
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return
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}
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return c.Conn.Write(b)
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}
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func (c *obfsHTTPConn) generateChallengeKey() (string, error) {
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p := make([]byte, 16)
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if _, err := io.ReadFull(rand.Reader, p); err != nil {
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return "", err
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}
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return base64.StdEncoding.EncodeToString(p), nil
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}
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