Initial commit: kport - SSH Port Forwarder TUI
- Interactive TUI for SSH port forwarding - Reads from ~/.ssh/config for host selection - Automatic port detection on remote hosts - Manual port forwarding option - Graceful error handling and connection timeouts - Built with Bubble Tea framework Co-authored-by: Ona <no-reply@ona.com>
This commit is contained in:
275
port_forwarder.go
Normal file
275
port_forwarder.go
Normal file
@@ -0,0 +1,275 @@
|
||||
package main
|
||||
|
||||
import (
|
||||
"fmt"
|
||||
"io"
|
||||
"net"
|
||||
"os"
|
||||
"strconv"
|
||||
"sync"
|
||||
"time"
|
||||
|
||||
tea "github.com/charmbracelet/bubbletea"
|
||||
"golang.org/x/crypto/ssh"
|
||||
"golang.org/x/crypto/ssh/agent"
|
||||
)
|
||||
|
||||
// ForwardingStartedMsg is sent when port forwarding starts
|
||||
type ForwardingStartedMsg struct {
|
||||
LocalPort int
|
||||
RemotePort int
|
||||
}
|
||||
|
||||
// PortForwarder manages SSH port forwarding
|
||||
type PortForwarder struct {
|
||||
sshClient *ssh.Client
|
||||
localPort int
|
||||
remotePort int
|
||||
listener net.Listener
|
||||
stopChan chan struct{}
|
||||
wg sync.WaitGroup
|
||||
isRunning bool
|
||||
mu sync.Mutex
|
||||
}
|
||||
|
||||
// NewPortForwarder creates a new port forwarder
|
||||
func NewPortForwarder(sshClient *ssh.Client, localPort, remotePort int) *PortForwarder {
|
||||
return &PortForwarder{
|
||||
sshClient: sshClient,
|
||||
localPort: localPort,
|
||||
remotePort: remotePort,
|
||||
stopChan: make(chan struct{}),
|
||||
}
|
||||
}
|
||||
|
||||
// Start starts the port forwarding
|
||||
func (pf *PortForwarder) Start() error {
|
||||
pf.mu.Lock()
|
||||
defer pf.mu.Unlock()
|
||||
|
||||
if pf.isRunning {
|
||||
return fmt.Errorf("port forwarding already running")
|
||||
}
|
||||
|
||||
// Create local listener
|
||||
listener, err := net.Listen("tcp", fmt.Sprintf("localhost:%d", pf.localPort))
|
||||
if err != nil {
|
||||
return fmt.Errorf("failed to create local listener: %w", err)
|
||||
}
|
||||
|
||||
pf.listener = listener
|
||||
pf.isRunning = true
|
||||
|
||||
// Start accepting connections
|
||||
pf.wg.Add(1)
|
||||
go pf.acceptConnections()
|
||||
|
||||
return nil
|
||||
}
|
||||
|
||||
// Stop stops the port forwarding
|
||||
func (pf *PortForwarder) Stop() {
|
||||
pf.mu.Lock()
|
||||
defer pf.mu.Unlock()
|
||||
|
||||
if !pf.isRunning {
|
||||
return
|
||||
}
|
||||
|
||||
pf.isRunning = false
|
||||
close(pf.stopChan)
|
||||
|
||||
if pf.listener != nil {
|
||||
pf.listener.Close()
|
||||
}
|
||||
|
||||
pf.wg.Wait()
|
||||
}
|
||||
|
||||
// acceptConnections accepts and handles incoming connections
|
||||
func (pf *PortForwarder) acceptConnections() {
|
||||
defer pf.wg.Done()
|
||||
|
||||
for {
|
||||
select {
|
||||
case <-pf.stopChan:
|
||||
return
|
||||
default:
|
||||
// Set a timeout for Accept to avoid blocking indefinitely
|
||||
if tcpListener, ok := pf.listener.(*net.TCPListener); ok {
|
||||
tcpListener.SetDeadline(time.Now().Add(1 * time.Second))
|
||||
}
|
||||
|
||||
conn, err := pf.listener.Accept()
|
||||
if err != nil {
|
||||
// Check if it's a timeout error and continue
|
||||
if netErr, ok := err.(net.Error); ok && netErr.Timeout() {
|
||||
continue
|
||||
}
|
||||
// If we're stopping, ignore the error
|
||||
select {
|
||||
case <-pf.stopChan:
|
||||
return
|
||||
default:
|
||||
continue
|
||||
}
|
||||
}
|
||||
|
||||
// Handle the connection in a separate goroutine
|
||||
pf.wg.Add(1)
|
||||
go pf.handleConnection(conn)
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
// handleConnection handles a single connection
|
||||
func (pf *PortForwarder) handleConnection(localConn net.Conn) {
|
||||
defer pf.wg.Done()
|
||||
defer localConn.Close()
|
||||
|
||||
// Create connection to remote host through SSH
|
||||
remoteConn, err := pf.sshClient.Dial("tcp", fmt.Sprintf("localhost:%d", pf.remotePort))
|
||||
if err != nil {
|
||||
return
|
||||
}
|
||||
defer remoteConn.Close()
|
||||
|
||||
// Copy data between connections
|
||||
var wg sync.WaitGroup
|
||||
wg.Add(2)
|
||||
|
||||
go func() {
|
||||
defer wg.Done()
|
||||
io.Copy(localConn, remoteConn)
|
||||
}()
|
||||
|
||||
go func() {
|
||||
defer wg.Done()
|
||||
io.Copy(remoteConn, localConn)
|
||||
}()
|
||||
|
||||
wg.Wait()
|
||||
}
|
||||
|
||||
// StartPortForwarding starts port forwarding for a specific port
|
||||
func StartPortForwarding(host SSHHost, remotePort int) tea.Cmd {
|
||||
return func() tea.Msg {
|
||||
// Find an available local port
|
||||
localPort, err := findAvailablePort()
|
||||
if err != nil {
|
||||
return ErrorMsg{Error: fmt.Errorf("failed to find available local port: %w", err)}
|
||||
}
|
||||
|
||||
// Create SSH client
|
||||
client, err := createSSHClient(host)
|
||||
if err != nil {
|
||||
return ErrorMsg{Error: fmt.Errorf("failed to create SSH client: %w", err)}
|
||||
}
|
||||
|
||||
// Create and start port forwarder
|
||||
forwarder := NewPortForwarder(client, localPort, remotePort)
|
||||
if err := forwarder.Start(); err != nil {
|
||||
client.Close()
|
||||
return ErrorMsg{Error: fmt.Errorf("failed to start port forwarding: %w", err)}
|
||||
}
|
||||
|
||||
return ForwardingStartedMsg{
|
||||
LocalPort: localPort,
|
||||
RemotePort: remotePort,
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
// StartManualPortForwarding starts port forwarding for a manually entered port
|
||||
func StartManualPortForwarding(host SSHHost, portStr string) tea.Cmd {
|
||||
return func() tea.Msg {
|
||||
remotePort, err := strconv.Atoi(portStr)
|
||||
if err != nil {
|
||||
return ErrorMsg{Error: fmt.Errorf("invalid port number: %s", portStr)}
|
||||
}
|
||||
|
||||
if remotePort <= 0 || remotePort > 65535 {
|
||||
return ErrorMsg{Error: fmt.Errorf("port number must be between 1 and 65535")}
|
||||
}
|
||||
|
||||
// Find an available local port
|
||||
localPort, err := findAvailablePort()
|
||||
if err != nil {
|
||||
return ErrorMsg{Error: fmt.Errorf("failed to find available local port: %w", err)}
|
||||
}
|
||||
|
||||
// Create SSH client
|
||||
client, err := createSSHClient(host)
|
||||
if err != nil {
|
||||
return ErrorMsg{Error: fmt.Errorf("failed to create SSH client: %w", err)}
|
||||
}
|
||||
|
||||
// Create and start port forwarder
|
||||
forwarder := NewPortForwarder(client, localPort, remotePort)
|
||||
if err := forwarder.Start(); err != nil {
|
||||
client.Close()
|
||||
return ErrorMsg{Error: fmt.Errorf("failed to start port forwarding: %w", err)}
|
||||
}
|
||||
|
||||
return ForwardingStartedMsg{
|
||||
LocalPort: localPort,
|
||||
RemotePort: remotePort,
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
// createSSHClient creates an SSH client for the given host
|
||||
func createSSHClient(host SSHHost) (*ssh.Client, error) {
|
||||
config := &ssh.ClientConfig{
|
||||
User: host.User,
|
||||
Auth: []ssh.AuthMethod{},
|
||||
HostKeyCallback: ssh.InsecureIgnoreHostKey(), // In production, use proper host key verification
|
||||
Timeout: 5 * time.Second, // Shorter timeout
|
||||
}
|
||||
|
||||
// Add key-based authentication if identity file is specified
|
||||
if host.Identity != "" {
|
||||
key, err := loadPrivateKey(host.Identity)
|
||||
if err == nil {
|
||||
config.Auth = append(config.Auth, ssh.PublicKeys(key))
|
||||
}
|
||||
}
|
||||
|
||||
// Add SSH agent authentication
|
||||
if agentAuth, err := sshAgentAuth(); err == nil {
|
||||
config.Auth = append(config.Auth, agentAuth)
|
||||
}
|
||||
|
||||
// Connect to the remote host
|
||||
addr := net.JoinHostPort(host.Hostname, host.Port)
|
||||
client, err := ssh.Dial("tcp", addr, config)
|
||||
if err != nil {
|
||||
return nil, fmt.Errorf("failed to connect to %s: %w", host.Name, err)
|
||||
}
|
||||
|
||||
return client, nil
|
||||
}
|
||||
|
||||
// sshAgentAuth returns SSH agent authentication method
|
||||
func sshAgentAuth() (ssh.AuthMethod, error) {
|
||||
// Try to connect to SSH agent
|
||||
agentConn, err := net.Dial("unix", os.Getenv("SSH_AUTH_SOCK"))
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
|
||||
sshAgent := agent.NewClient(agentConn)
|
||||
return ssh.PublicKeysCallback(sshAgent.Signers), nil
|
||||
}
|
||||
|
||||
// findAvailablePort finds an available local port
|
||||
func findAvailablePort() (int, error) {
|
||||
listener, err := net.Listen("tcp", ":0")
|
||||
if err != nil {
|
||||
return 0, err
|
||||
}
|
||||
defer listener.Close()
|
||||
|
||||
addr := listener.Addr().(*net.TCPAddr)
|
||||
return addr.Port, nil
|
||||
}
|
||||
Reference in New Issue
Block a user