Add api command

cmd/sing-box/cmd_api_tailscale_ssh.go

@@ -0,0 +1,78 @@
+package main
+
+import (
+	"os/exec"
+	"os/user"
+	"strings"
+
+	E "github.com/sagernet/sing/common/exceptions"
+
+	"github.com/spf13/cobra"
+)
+
+var commandAPITailscaleSSH = &cobra.Command{
+	Use:   "ssh [user@]<peer>",
+	Short: "SSH into a Tailscale peer",
+	Long: "SSH into a Tailscale peer.\n\n" +
+		"The local ssh binary is executed against the Tailscale address of the peer, so the machine running " +
+		"this command must be able to route Tailscale addresses into the Tailscale endpoint itself, " +
+		"usually by running behind a sing-box instance with a tun inbound.\n\n" +
+		"The user defaults to the current user, and Tailscale SSH authentication is not available: " +
+		"the peer is reached as an ordinary SSH server.",
+	Args: cobra.ExactArgs(1),
+	RunE: func(cmd *cobra.Command, args []string) error {
+		return runAPITailscaleSSH(args[0])
+	},
+}
+
+func init() {
+	commandAPITailscaleSSH.Flags().StringVar(&commandAPITailscaleFlagEndpoint, "endpoint", "", commandAPITailscaleEndpointUsage)
+	commandAPITailscale.AddCommand(commandAPITailscaleSSH)
+}
+
+func runAPITailscaleSSH(target string) error {
+	loginName := ""
+	selector := target
+	nameIndex := strings.LastIndex(target, "@")
+	if nameIndex != -1 {
+		loginName = target[:nameIndex]
+		selector = target[nameIndex+1:]
+	}
+	if loginName == "" {
+		currentUser, userErr := user.Current()
+		if userErr == nil {
+			loginName = currentUser.Username
+			_, domainUserName, isDomainUser := strings.Cut(loginName, "\\")
+			if isDomainUser {
+				loginName = domainUserName
+			}
+		}
+	}
+	clientConn, client, err := createAPIClient()
+	if err != nil {
+		return err
+	}
+	defer clientConn.Close()
+	endpoint, err := fetchTailscaleEndpoint(client)
+	if err != nil {
+		return err
+	}
+	entry, err := resolveTailscalePeer(tailscalePeerEntries(endpoint), selector)
+	if err != nil {
+		return err
+	}
+	peerAddress := tailscalePeerAddress(entry.peer)
+	if peerAddress == "" {
+		return E.New("peer has no tailscale address: ", tailscalePeerName(entry.peer))
+	}
+	clientConn.Close()
+	sshPath, err := exec.LookPath("ssh")
+	if err != nil {
+		return E.New("ssh not found in PATH")
+	}
+	destination := peerAddress
+	if loginName != "" {
+		destination = loginName + "@" + peerAddress
+	}
+	return executeSSH(sshPath, []string{"ssh", destination})
+}