sing-box/transport/simple-obfs/http.go

95 lines
2 KiB
Go

package obfs
import (
"bytes"
"encoding/base64"
"fmt"
"io"
"math/rand"
"net"
"net/http"
B "github.com/sagernet/sing/common/buf"
)
// HTTPObfs is shadowsocks http simple-obfs implementation
type HTTPObfs struct {
net.Conn
host string
port string
buf []byte
offset int
firstRequest bool
firstResponse bool
}
func (ho *HTTPObfs) Read(b []byte) (int, error) {
if ho.buf != nil {
n := copy(b, ho.buf[ho.offset:])
ho.offset += n
if ho.offset == len(ho.buf) {
B.Put(ho.buf)
ho.buf = nil
}
return n, nil
}
if ho.firstResponse {
buf := B.Get(B.BufferSize)
n, err := ho.Conn.Read(buf)
if err != nil {
B.Put(buf)
return 0, err
}
idx := bytes.Index(buf[:n], []byte("\r\n\r\n"))
if idx == -1 {
B.Put(buf)
return 0, io.EOF
}
ho.firstResponse = false
length := n - (idx + 4)
n = copy(b, buf[idx+4:n])
if length > n {
ho.buf = buf[:idx+4+length]
ho.offset = idx + 4 + n
} else {
B.Put(buf)
}
return n, nil
}
return ho.Conn.Read(b)
}
func (ho *HTTPObfs) Write(b []byte) (int, error) {
if ho.firstRequest {
randBytes := make([]byte, 16)
rand.Read(randBytes)
req, _ := http.NewRequest("GET", fmt.Sprintf("http://%s/", ho.host), bytes.NewBuffer(b[:]))
req.Header.Set("User-Agent", fmt.Sprintf("curl/7.%d.%d", rand.Int()%54, rand.Int()%2))
req.Header.Set("Upgrade", "websocket")
req.Header.Set("Connection", "Upgrade")
req.Host = ho.host
if ho.port != "80" {
req.Host = fmt.Sprintf("%s:%s", ho.host, ho.port)
}
req.Header.Set("Sec-WebSocket-Key", base64.URLEncoding.EncodeToString(randBytes))
req.ContentLength = int64(len(b))
err := req.Write(ho.Conn)
ho.firstRequest = false
return len(b), err
}
return ho.Conn.Write(b)
}
// NewHTTPObfs return a HTTPObfs
func NewHTTPObfs(conn net.Conn, host string, port string) net.Conn {
return &HTTPObfs{
Conn: conn,
firstRequest: true,
firstResponse: true,
host: host,
port: port,
}
}