1 files changed, 237 insertions, 0 deletions
diff --git a/webircgateway/pkg/proxy/server.go b/webircgateway/pkg/proxy/server.go
new file mode 100644
index 0000000..7e3f62f
--- /dev/null
+++ b/webircgateway/pkg/proxy/server.go
@@ -0,0 +1,237 @@
+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 ""
+}