Initial ssh tunnel implementation

pkg/client/tunnel.go

@@ -0,0 +1,127 @@
+package client
+
+import (
+	"fmt"
+	"io"
+	"io/ioutil"
+	"log"
+	"net"
+	"os"
+	"sync"
+
+	"golang.org/x/crypto/ssh"
+
+	"github.com/sosedoff/pgweb/pkg/connection"
+)
+
+const (
+	PORT_START = 29168
+	PORT_LIMIT = 500
+)
+
+type Tunnel struct {
+	TargetHost string
+	TargetPort string
+
+	SshHost     string
+	SshPort     string
+	SshUser     string
+	SshPassword string
+	SshKey      string
+
+	Config *ssh.ClientConfig
+	Client *ssh.Client
+}
+
+func privateKeyPath() string {
+	return os.Getenv("HOME") + "/.ssh/id_rsa"
+}
+
+func parsePrivateKey(keyPath string) (ssh.Signer, error) {
+	buff, err := ioutil.ReadFile(keyPath)
+	if err != nil {
+		return nil, err
+	}
+
+	return ssh.ParsePrivateKey(buff)
+}
+
+func makeConfig(user, password, keyPath string) (*ssh.ClientConfig, error) {
+	methods := []ssh.AuthMethod{}
+
+	if keyPath != "" {
+		key, err := parsePrivateKey(keyPath)
+		if err != nil {
+			return nil, err
+		}
+
+		methods = append(methods, ssh.PublicKeys(key))
+	}
+
+	methods = append(methods, ssh.Password(password))
+
+	return &ssh.ClientConfig{User: user, Auth: methods}, nil
+}
+
+func (tunnel *Tunnel) sshEndpoint() string {
+	return fmt.Sprintf("%s:%v", tunnel.SshHost, tunnel.SshPort)
+}
+
+func (tunnel *Tunnel) targetEndpoint() string {
+	return fmt.Sprintf("%v:%v", tunnel.TargetHost, tunnel.TargetPort)
+}
+
+func (tunnel *Tunnel) Start() error {
+	config, err := makeConfig(tunnel.SshUser, tunnel.SshPassword, tunnel.SshKey)
+	if err != nil {
+		return err
+	}
+
+	client, err := ssh.Dial("tcp", tunnel.sshEndpoint(), config)
+	if err != nil {
+		return err
+	}
+	defer client.Close()
+
+	port, err := connection.AvailablePort(PORT_START, PORT_LIMIT)
+	if err != nil {
+		return err
+	}
+
+	listener, err := net.Listen("tcp", fmt.Sprintf("127.0.0.1:%v", port))
+	if err != nil {
+		return err
+	}
+	defer listener.Close()
+
+	for {
+		conn, err := listener.Accept()
+		if err != nil {
+			return err
+		}
+
+		go tunnel.handleConnection(conn, client)
+	}
+}
+
+func (tunnel *Tunnel) copy(wg *sync.WaitGroup, writer, reader net.Conn) {
+	defer wg.Done()
+	if _, err := io.Copy(writer, reader); err != nil {
+		log.Println("Tunnel copy error:", err)
+	}
+}
+
+func (tunnel *Tunnel) handleConnection(local net.Conn, sshClient *ssh.Client) {
+	remote, err := sshClient.Dial("tcp", tunnel.targetEndpoint())
+	if err != nil {
+		return
+	}
+
+	wg := sync.WaitGroup{}
+	wg.Add(2)
+
+	go tunnel.copy(&wg, local, remote)
+	go tunnel.copy(&wg, remote, local)
+
+	wg.Wait()
+}