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|
package proxy
import (
"bufio"
"crypto/tls"
"encoding/json"
"fmt"
"io"
"log"
"net"
"strconv"
"sync"
"syscall"
"time"
"github.com/kiwiirc/webircgateway/pkg/identd"
)
const (
ResponseError = "0"
ResponseOK = "1"
ResponseReset = "2"
ResponseRefused = "3"
ResponseUnknownHost = "4"
ResponseTimeout = "5"
)
var identdRpc *identd.RpcClient
var Server net.Listener
type HandshakeMeta struct {
Host string `json:"host"`
Port int `json:"port"`
TLS bool `json:"ssl"`
Username string `json:"username"`
Interface string `json:"interface"`
}
func MakeClient(conn net.Conn) *Client {
return &Client{
Client: conn,
}
}
type Client struct {
Client net.Conn
Upstream net.Conn
UpstreamAddr *net.TCPAddr
Username string
BindAddr *net.TCPAddr
TLS bool
}
func (c *Client) Run() {
var err error
err = c.Handshake()
if err != nil {
log.Println(err.Error())
return
}
err = c.ConnectUpstream()
if err != nil {
log.Println(err.Error())
return
}
c.Pipe()
}
func (c *Client) Handshake() error {
// Read the first line - it should be JSON
reader := bufio.NewReader(c.Client)
line, readErr := reader.ReadBytes('\n')
if readErr != nil {
return readErr
}
var meta = HandshakeMeta{
Username: "user",
Port: 6667,
Interface: "0.0.0.0",
}
unmarshalErr := json.Unmarshal(line, &meta)
if unmarshalErr != nil {
c.Client.Write([]byte(ResponseError))
return unmarshalErr
}
if meta.Host == "" || meta.Port == 0 || meta.Username == "" || meta.Interface == "" {
c.Client.Write([]byte(ResponseError))
return fmt.Errorf("missing args")
}
c.Username = meta.Username
c.TLS = meta.TLS
bindAddr, bindAddrErr := net.ResolveTCPAddr("tcp", meta.Interface+":")
if bindAddrErr != nil {
c.Client.Write([]byte(ResponseError))
return fmt.Errorf("interface: " + bindAddrErr.Error())
}
c.BindAddr = bindAddr
hostStr := net.JoinHostPort(meta.Host, strconv.Itoa(meta.Port))
addr, addrErr := net.ResolveTCPAddr("tcp", hostStr)
if addrErr != nil {
c.Client.Write([]byte(ResponseUnknownHost))
return fmt.Errorf("remote host: " + addrErr.Error())
}
c.UpstreamAddr = addr
return nil
}
func (c *Client) ConnectUpstream() error {
dialer := &net.Dialer{}
dialer.LocalAddr = c.BindAddr
dialer.Timeout = time.Second * 10
conn, err := dialer.Dial("tcp", c.UpstreamAddr.String())
if err != nil {
response := ""
errType := typeOfErr(err)
switch errType {
case "timeout":
response = ResponseTimeout
case "unknown_host":
response = ResponseUnknownHost
case "refused":
response = ResponseRefused
}
c.Client.Write([]byte(response))
return err
}
if identdRpc != nil {
lAddr, lPortStr, _ := net.SplitHostPort(conn.LocalAddr().String())
lPort, _ := strconv.Atoi(lPortStr)
identdRpc.AddIdent(lPort, c.UpstreamAddr.Port, c.Username, lAddr)
}
if c.TLS {
tlsConfig := &tls.Config{InsecureSkipVerify: true}
tlsConn := tls.Client(conn, tlsConfig)
err := tlsConn.Handshake()
if err != nil {
conn.Close()
c.Client.Write([]byte(ResponseReset))
return err
}
conn = net.Conn(tlsConn)
}
c.Upstream = conn
c.Client.Write([]byte(ResponseOK))
return nil
}
func (c *Client) Pipe() {
wg := sync.WaitGroup{}
wg.Add(2)
go func() {
io.Copy(c.Client, c.Upstream)
c.Client.Close()
wg.Done()
}()
go func() {
io.Copy(c.Upstream, c.Client)
c.Upstream.Close()
wg.Done()
}()
wg.Wait()
if identdRpc != nil {
lAddr, lPortStr, _ := net.SplitHostPort(c.Upstream.LocalAddr().String())
lPort, _ := strconv.Atoi(lPortStr)
identdRpc.RemoveIdent(lPort, c.UpstreamAddr.Port, c.Username, lAddr)
}
}
func Start(laddr string) {
srv, err := net.Listen("tcp", laddr)
if err != nil {
log.Fatal(err.Error())
}
// Expose the server
Server = srv
log.Printf("Kiwi proxy listening on %s", srv.Addr().String())
identdRpc = identd.MakeRpcClient("kiwiproxy" + laddr)
go identdRpc.ConnectAndReconnect("127.0.0.1:1133")
for {
conn, err := srv.Accept()
if err != nil {
log.Print(err.Error())
break
}
c := MakeClient(conn)
go c.Run()
}
}
func typeOfErr(err error) string {
if err == nil {
return ""
}
if netError, ok := err.(net.Error); ok && netError.Timeout() {
return "timeout"
}
switch t := err.(type) {
case *net.OpError:
if t.Op == "dial" {
return "unknown_host"
} else if t.Op == "read" {
return "refused"
}
case syscall.Errno:
if t == syscall.ECONNREFUSED {
return "refused"
}
}
return ""
}
|
