route/internal/tun2/client.go

140 lines
2.2 KiB
Go

package tun2
import (
"crypto/tls"
"encoding/json"
"errors"
"log"
"net"
"net/http"
"net/http/httputil"
"net/url"
kcp "github.com/xtaci/kcp-go"
"github.com/xtaci/smux"
)
type Client struct {
cfg *ClientConfig
}
type ClientConfig struct {
TLSConfig *tls.Config
ConnType string
ServerAddr string
Token string
Domain string
BackendURL string
}
func NewClient(cfg *ClientConfig) (*Client, error) {
if cfg == nil {
return nil, errors.New("tun2: client config needed")
}
c := &Client{
cfg: cfg,
}
return c, nil
}
func (c *Client) Connect() error {
return c.connect(c.cfg.ServerAddr)
}
func (c *Client) connect(serverAddr string) error {
target, err := url.Parse(c.cfg.BackendURL)
if err != nil {
return err
}
s := &http.Server{
Handler: httputil.NewSingleHostReverseProxy(target),
}
var conn net.Conn
switch c.cfg.ConnType {
case "tcp":
conn, err = tls.Dial("tcp", serverAddr, c.cfg.TLSConfig)
if err != nil {
return err
}
case "kcp":
kc, err := kcp.Dial(serverAddr)
if err != nil {
return err
}
defer kc.Close()
serverHost, _, _ := net.SplitHostPort(serverAddr)
tc := c.cfg.TLSConfig.Clone()
tc.ServerName = serverHost
conn = tls.Client(kc, tc)
}
defer conn.Close()
log.Printf("tun2: connected to %s (%v)", conn.RemoteAddr(), c.cfg.ConnType)
session, err := smux.Client(conn, smux.DefaultConfig())
if err != nil {
return err
}
defer session.Close()
controlStream, err := session.AcceptStream()
if err != nil {
return err
}
authData, err := json.Marshal(&Auth{
Token: c.cfg.Token,
Domain: c.cfg.Domain,
})
if err != nil {
return err
}
_, err = controlStream.Write(authData)
if err != nil {
return err
}
log.Println("tun2: client set up and waiting for requests")
err = s.Serve(&smuxListener{
conn: conn,
session: session,
})
if err != nil {
return err
}
return nil
}
type smuxListener struct {
conn net.Conn
session *smux.Session
}
var (
_ net.Listener = &smuxListener{} // interface check
)
func (sl *smuxListener) Accept() (net.Conn, error) {
return sl.session.AcceptStream()
}
func (sl *smuxListener) Addr() net.Addr {
return sl.conn.LocalAddr()
}
func (sl *smuxListener) Close() error {
return sl.session.Close()
}