feat: initial webssh tooling

2026-07-26 15:58:14 +00:00 · 2025-05-30 19:35:47 -04:00
parent f6d8ad25e1
commit 7dfcbef774
16 changed files with 792 additions and 83 deletions
@@ -1,9 +1,12 @@
 package main

 import (
+	"os"
+
 	_ "github.com/joho/godotenv/autoload"
 	"github.com/tale/headplane/agent/internal/config"
 	"github.com/tale/headplane/agent/internal/hpagent"
+	"github.com/tale/headplane/agent/internal/sshutil"
 	"github.com/tale/headplane/agent/internal/tsnet"
 	"github.com/tale/headplane/agent/internal/util"
 )
@@ -31,5 +34,6 @@ func main() {
 		ID:   agent.ID,
 	})

+	sshutil.StartInputReader(os.NewFile(3, "sshin"))
 	hpagent.FollowMaster(agent)
 }
@@ -2,13 +2,16 @@ package hpagent

 import (
 	"bufio"
-	"encoding/json"
+	"bytes"
+	// "encoding/json"
 	"os"
-	"sync"
+	// "sync"

+	"github.com/fxamacker/cbor/v2"
+	"github.com/tale/headplane/agent/internal/sshutil"
 	"github.com/tale/headplane/agent/internal/tsnet"
 	"github.com/tale/headplane/agent/internal/util"
-	"tailscale.com/tailcfg"
+	// "tailscale.com/tailcfg"
 )

 // Represents messages from the Headplane master
@@ -16,6 +19,25 @@ type RecvMessage struct {
 	NodeIDs []string
 }

+type CborMessage struct {
+	Op string `cbor:"op"`
+	Payload cbor.RawMessage `cbor:"payload"`
+}
+
+type SSHConnect struct {
+	SessionId string `cbor:"sessionId"`
+	Username string `cbor:"username"`
+	Hostname string `cbor:"hostname"`
+	Port int `cbor:"port"`
+}
+
+type SSHMessage struct {
+	op string
+	username string
+	hostname string
+	Id string
+}
+
 type SendMessage struct {
 	Type string
 	Data any
@@ -25,63 +47,111 @@ type SendMessage struct {
 func FollowMaster(agent *tsnet.TSAgent) {
 	log := util.GetLogger()
 	scanner := bufio.NewScanner(os.Stdin)
+	log.Info("Listening for messages from Headplane master on stdin")

 	for scanner.Scan() {
 		line := scanner.Bytes()
+		log.Info("Got bytes delimited by newline");
+
+		var msg CborMessage
+		decoder := cbor.NewDecoder(bytes.NewReader(line))
+		err := decoder.Decode(&msg)

-		var msg RecvMessage
-		err := json.Unmarshal(line, &msg)
 		if err != nil {
-			log.Error("Unable to unmarshal message: %s", err)
-			log.Debug("Full Error: %v", err)
-			continue
+			log.Error("Unable to decode message from master: %s", err)
+			continue;
 		}

-		log.Debug("Recieved message from master: %v", line)
-
-		if len(msg.NodeIDs) == 0 {
-			log.Debug("Message recieved had no node IDs")
-			log.Debug("Full message: %s", line)
-			continue
+		log.Debug("Received message from master: %s", msg)
+		var sshPayload SSHConnect
+		err = cbor.Unmarshal(msg.Payload, &sshPayload)
+		if err != nil {
+			log.Error("Unable to unmarshal SSH connect payload: %s", err)
+			continue;
 		}

-		// Accumulate the results since we invoke via gofunc
-		results := make(map[string]*tailcfg.HostinfoView)
-		mu := sync.Mutex{}
-		wg := sync.WaitGroup{}
-
-		for _, nodeID := range msg.NodeIDs {
-			wg.Add(1)
-			go func(nodeID string) {
-				defer wg.Done()
-				result, err := agent.GetStatusForPeer(nodeID)
-				if err != nil {
-					log.Error("Unable to get status for node %s: %s", nodeID, err)
-					return
-				}
-
-				if result == nil {
-					log.Debug("No status for node %s", nodeID)
-					return
-				}
-
-				mu.Lock()
-				results[nodeID] = result
-				mu.Unlock()
-			}(nodeID)
-		}
-
-		wg.Wait()
-
-		// Send the results back to the Headplane master
-		log.Debug("Sending status back to master: %v", results)
-		log.Msg(&SendMessage{
-			Type: "status",
-			Data: results,
+		log.Info("Opening SSH PTY for session %s to %s@%s:%d", sshPayload.SessionId, sshPayload.Username, sshPayload.Hostname, sshPayload.Port)
+		sshutil.OpenSshPty(agent, sshutil.SshConnectParams{
+			Hostname: sshPayload.Hostname,
+			Port: sshPayload.Port,
+			Username: sshPayload.Username,
+			Id: sshPayload.SessionId,
 		})
 	}

-	if err := scanner.Err(); err != nil {
-		log.Fatal("Error reading from stdin: %s", err)
-	}
+
+
+	// 	var msg RecvMessage
+	// 	err := json.Unmarshal(line, &msg)
+	// 	if err != nil {
+	// 		var cborMsg CborMessage
+	// 		dec := cbor.NewDecoder(bytes.NewReader(line))
+	// 		err := dec.Decode(&cborMsg)
+
+	// 		if err == nil {
+	// 			log.Info("Unmarshalled CBOR message: %s", cborMsg)
+	// 			var sshPayload SSHConnect
+	// 			err = cbor.Unmarshal(cborMsg.Payload, &sshPayload)
+	// 			sshutil.OpenSshPty(agent, sshutil.SshConnectParams{
+	// 				Hostname: sshPayload.Hostname,
+	// 				Port: sshPayload.Port,
+	// 				Username: sshPayload.Username,
+	// 				Id: sshPayload.SessionId,
+	// 			})
+
+	// 			return;
+	// 		}
+
+	// 		log.Error("Unable to unmarshal message: %s", err)
+	// 		log.Debug("Full Error: %v", err)
+	// 		continue
+	// 	}
+
+	// 	log.Debug("Recieved message from master: %v", line)
+
+	// 	if len(msg.NodeIDs) == 0 {
+	// 		log.Debug("Message recieved had no node IDs")
+	// 		log.Debug("Full message: %s", line)
+	// 		continue
+	// 	}
+
+	// 	// Accumulate the results since we invoke via gofunc
+	// 	results := make(map[string]*tailcfg.HostinfoView)
+	// 	mu := sync.Mutex{}
+	// 	wg := sync.WaitGroup{}
+
+	// 	for _, nodeID := range msg.NodeIDs {
+	// 		wg.Add(1)
+	// 		go func(nodeID string) {
+	// 			defer wg.Done()
+	// 			result, err := agent.GetStatusForPeer(nodeID)
+	// 			if err != nil {
+	// 				log.Error("Unable to get status for node %s: %s", nodeID, err)
+	// 				return
+	// 			}
+
+	// 			if result == nil {
+	// 				log.Debug("No status for node %s", nodeID)
+	// 				return
+	// 			}
+
+	// 			mu.Lock()
+	// 			results[nodeID] = result
+	// 			mu.Unlock()
+	// 		}(nodeID)
+	// 	}
+
+	// 	wg.Wait()
+
+	// 	// Send the results back to the Headplane master
+	// 	log.Debug("Sending status back to master: %v", results)
+	// 	log.Msg(&SendMessage{
+	// 		Type: "status",
+	// 		Data: results,
+	// 	})
+	// }
+
+	// if err := scanner.Err(); err != nil {
+	// 	log.Fatal("Error reading from stdin: %s", err)
+	// }
 }
@@ -0,0 +1,161 @@
+package sshutil
+
+import (
+	"context"
+	"errors"
+	"io"
+	"os"
+	"strconv"
+	"strings"
+
+	"github.com/tale/headplane/agent/internal/tsnet"
+	"github.com/tale/headplane/agent/internal/util"
+	"golang.org/x/crypto/ssh"
+)
+
+type SshConnectParams struct {
+	Hostname string
+	Port     int
+	Username string
+	Id 	 string
+}
+
+func dialAndValidateTailscaleSSH(agent *tsnet.TSAgent, params SshConnectParams) (*ssh.Client, error) {
+	log := util.GetLogger()
+
+	addr := strings.Join([]string{params.Hostname, ":", strconv.Itoa(params.Port)}, "")
+
+	log.Debug("Attempting to dial %s via Tailscale SSH", addr)
+	conn, err := agent.Dial(context.Background(), "tcp", addr)
+	if err != nil {
+		log.Error("Failed to connect to Tailscale SSH: %s", err)
+		return nil, err
+	}
+
+	log.Debug("Connected to Tailscale SSH at %s", addr)
+	config := &ssh.ClientConfig{
+		User: params.Username,
+		HostKeyCallback: ssh.InsecureIgnoreHostKey(),
+	}
+
+	clientConn, chans, reqs, err := ssh.NewClientConn(conn, addr, config)
+	if err != nil {
+		log.Error("Failed to create SSH client connection: %s", err)
+		conn.Close()
+		return nil, err
+	}
+
+	client := ssh.NewClient(clientConn, chans, reqs)
+	sVer := string(client.ServerVersion())
+
+	if !strings.Contains(sVer, "Tailscale") {
+		log.Error("Connected to non-Tailscale SSH server: %s", sVer)
+		conn.Close()
+		return nil, errors.New("not a Tailscale SSH server")
+	}
+
+	log.Info("Connected to SSH server running %s at %s", client.ServerVersion(), addr)
+	return client, nil
+}
+
+func bindStdinToFd(sess *ssh.Session, fd int) error {
+	log := util.GetLogger()
+
+	sshIn := os.NewFile(uintptr(fd), "sshInput")
+	if sshIn == nil {
+		log.Error("Failed to create file from stdin fd %d", fd)
+		return errors.New("failed to create file from stdin fd")
+	}
+
+	stdin, err := sess.StdinPipe()
+	if err != nil {
+		log.Error("Failed to get stdin pipe: %s", err)
+		return err
+	}
+
+	go io.Copy(stdin, sshIn) // From Node → SSH session
+	return nil
+}
+
+func bindStdoutToFd(sess *ssh.Session, fd int) error {
+	log := util.GetLogger()
+
+	sshOut := os.NewFile(uintptr(fd), "sshOutput")
+	if sshOut == nil {
+		log.Error("Failed to create file from stdout fd %d", fd)
+		return errors.New("failed to create file from stdout fd")
+	}
+
+	stdout, err := sess.StdoutPipe()
+	if err != nil {
+		log.Error("Failed to get stdout pipe: %s", err)
+		return err
+	}
+
+	go io.Copy(sshOut, stdout) // From SSH → Node
+	return nil
+}
+
+func OpenSshPty(agent *tsnet.TSAgent, params SshConnectParams) (*ssh.Client, error) {
+	log := util.GetLogger()
+
+	if agent == nil {
+		log.Error("Tailscale agent is nil")
+		return nil, errors.New("tailscale agent is nil")
+	}
+
+	if params.Hostname == "" || params.Port <= 0 || params.Username == "" {
+		log.Error("Invalid SSH connection parameters: %+v", params)
+		return nil, errors.New("invalid SSH connection parameters")
+	}
+
+	client, err := dialAndValidateTailscaleSSH(agent, params)
+	if err != nil {
+		log.Error("Failed to open SSH pty: %s", err)
+		return nil, err
+	}
+
+	go func() {
+	sess, err := client.NewSession()
+	if err != nil {
+		log.Error("Failed to create new SSH session: %s", err)
+		client.Close()
+	}
+
+	modes := ssh.TerminalModes{
+		ssh.ECHO:          1, // enable echoing
+		ssh.TTY_OP_ISPEED: 14400,
+		ssh.TTY_OP_OSPEED: 14400,
+	}
+
+	if err := sess.RequestPty("xterm-256color", 80, 40, modes); err != nil {
+		log.Error("Failed to request PTY: %s", err)
+		client.Close()
+	}
+
+	ctx := addSession(params.Id, sess)
+	go func() {
+		for data := range ctx.InputCh {
+			if _, err := ctx.Stdin.Write(data); err != nil {
+				log.Error("Failed to write to SSH stdin: %s", err)
+				return
+			}
+		}
+	}();
+
+	if err := sess.Shell(); err != nil {
+		log.Error("Failed to start shell: %s", err)
+		client.Close()
+	}
+
+
+	log.Info("Successfully opened SSH pty for %s@%s:%d", params.Username, params.Hostname, params.Port)
+	go streamSSHOutput(params.Id, ctx.Stdout, os.NewFile(4, "sshOutput"))
+		sess.Wait();
+		sess.Close();
+		log.Info("SSH session %s closed (goSide)", params.Id)
+		RemoveSession(params.Id)
+	}()
+
+	return client, nil
+}
@@ -0,0 +1,41 @@
+package sshutil
+
+import (
+	"encoding/binary"
+	"fmt"
+)
+
+func encodeFrame(id string, data []byte) ([]byte, error) {
+	sid := []byte(id)
+	if len(sid) > 255 {
+		return nil, fmt.Errorf("session ID too long")
+	}
+
+	payloadLen := len(data)
+	buf := make([]byte, 1+len(sid)+4+payloadLen)
+
+	buf[0] = byte(len(sid))                                          // SID length
+	copy(buf[1:], sid)                                               // SID
+	binary.BigEndian.PutUint32(buf[1+len(sid):], uint32(payloadLen)) // Payload length
+	copy(buf[1+len(sid)+4:], data)                                   // Payload
+
+	return buf, nil
+}
+
+func decodeFrame(buf []byte) (id string, payload []byte, ok bool) {
+	if len(buf) < 5 {
+		return "", nil, false
+	}
+	sidLen := int(buf[0])
+	if len(buf) < 1+sidLen+4 {
+		return "", nil, false
+	}
+	id = string(buf[1 : 1+sidLen])
+	payloadLen := int(binary.BigEndian.Uint32(buf[1+sidLen:]))
+
+	if len(buf) < 1+sidLen+4+payloadLen {
+		return "", nil, false
+	}
+	payload = buf[1+sidLen+4 : 1+sidLen+4+payloadLen]
+	return id, payload, true
+}
@@ -0,0 +1,56 @@
+package sshutil
+
+import (
+	"io"
+
+	"github.com/tale/headplane/agent/internal/util"
+)
+
+func StartInputReader(fd3 io.Reader) {
+	log := util.GetLogger();
+
+	log.Info("Starting SSH fd3 input reader")
+	go func() {
+		buffer := make([]byte, 8192)
+		for {
+			n, err := fd3.Read(buffer)
+			if err != nil {
+				log.Error("fd3 read error: %v", err)
+				return
+			}
+			offset := 0
+			for offset < n {
+				id, payload, ok := decodeFrame(buffer[offset:n])
+				if !ok {
+					break // Wait for more data
+				}
+				offset += 1 + len(id) + 4 + len(payload)
+
+				sessionsMu.RLock()
+				sess, ok := sessions[id]
+				sessionsMu.RUnlock()
+				if !ok {
+					log.Error("invalid session id: %s", id)
+					continue
+				}
+				_, err := sess.Stdin.Write(payload)
+				if err != nil {
+					log.Error("failed to write to session stdin: %v", err)
+					continue
+				}
+			}
+		}
+	}()
+}
+
+func streamSSHOutput(id string, r io.Reader, fd4 io.Writer) {
+	buf := make([]byte, 1024)
+	for {
+		n, err := r.Read(buf)
+		if err != nil {
+			break
+		}
+		frame, _ := encodeFrame(id, buf[:n])
+		fd4.Write(frame)
+	}
+}
@@ -0,0 +1,67 @@
+package sshutil
+
+import (
+	"io"
+	"sync"
+
+	"golang.org/x/crypto/ssh"
+)
+
+type SessionContext struct {
+	ID      string
+	Session *ssh.Session
+	Stdin   io.WriteCloser
+	Stdout  io.Reader
+	InputCh chan []byte
+}
+
+var sessions = make(map[string]*SessionContext)
+var sessionsMu sync.RWMutex
+
+func addSession(id string, session *ssh.Session) *SessionContext {
+	sessionsMu.Lock()
+	defer sessionsMu.Unlock()
+
+	if _, exists := sessions[id]; exists {
+		return nil // Session with this ID already exists
+	}
+
+	stdin, err := session.StdinPipe()
+	if err != nil {
+		return nil // Handle error appropriately in production code
+	}
+
+	stdout, err := session.StdoutPipe()
+	if err != nil {
+		stdin.Close() // Close stdin if stdout pipe creation fails
+		return nil // Handle error appropriately in production code
+	}
+
+	sessionContext := &SessionContext{
+		ID:      id,
+		Session: session,
+		Stdin:   stdin,
+		Stdout:  stdout,
+	}
+
+	sessions[id] = sessionContext
+	return sessionContext
+}
+
+func GetSession(id string) *SessionContext {
+	sessionsMu.RLock()
+	defer sessionsMu.RUnlock()
+
+	return sessions[id] // Returns nil if session does not exist
+}
+
+func RemoveSession(id string) {
+	sessionsMu.Lock()
+	defer sessionsMu.Unlock()
+
+	if sessionContext, exists := sessions[id]; exists {
+		sessionContext.Stdin.Close() // Close the stdin pipe
+		sessionContext.Session.Close() // Close the SSH session
+		delete(sessions, id) // Remove from the map
+	}
+}
@@ -107,11 +107,34 @@ func (l *Logger) Msg(obj any) {
 }

 func escapeString(s string) string {
-	replacer := strings.NewReplacer(
-		`"`, `\"`,
-		`\`, `\\`,
-		"\n", `\n`,
-		"\t", `\t`,
-	)
-	return replacer.Replace(s)
+	var b strings.Builder
+	b.Grow(len(s) + 16) // pre-grow to reduce reallocs
+
+	for i := 0; i < len(s); i++ {
+		c := s[i]
+		switch c {
+		case '"':
+			b.WriteString(`\"`)
+		case '\\':
+			b.WriteString(`\\`)
+		case '\b':
+			b.WriteString(`\b`)
+		case '\f':
+			b.WriteString(`\f`)
+		case '\n':
+			b.WriteString(`\n`)
+		case '\r':
+			b.WriteString(`\r`)
+		case '\t':
+			b.WriteString(`\t`)
+		default:
+			if c < 0x20 {
+				// Control characters like 0x01, 0x07 (bell), etc.
+				fmt.Fprintf(&b, `\u%04x`, c)
+			} else {
+				b.WriteByte(c)
+			}
+		}
+	}
+	return b.String()
 }
@@ -7,6 +7,10 @@ many side-effects (in this case, importing a module may run code).
 ```
 server
 ├── index.ts: Loads everything and starts the web server.
+├── agent/
+│   ├── dispatcher.ts: Serializes commands for the agent control fd (stdin).
+│   ├── ssh.ts: Manages & multiplexes the active web SSH connections
+│   ├── env.ts: Checks the environment variables for custom overrides.
 ├── config/
 │   ├── integration/
 │   │   ├── abstract.ts: Defines the abstract class for integrations.
@@ -0,0 +1,36 @@
+import type { Writable } from 'node:stream';
+import { decode, encode } from 'cbor2';
+
+interface Command {
+	op: string;
+	payload: unknown;
+}
+
+interface SSHConnectCommand extends Command {
+	op: 'ssh_conn';
+	payload: {
+		sessionId: string;
+		username: string;
+		hostname: string;
+		port: number;
+	};
+}
+
+type AgentCommand = SSHConnectCommand;
+
+export async function dispatchCommand(
+	dispatcher: Writable,
+	command: AgentCommand,
+) {
+	return new Promise<void>((resolve, reject) => {
+		const encodedCommand = Buffer.concat([encode(command), Buffer.from('\n')]);
+		dispatcher.write(encodedCommand, (err) => {
+			console.log('Command dispatched:', command, err);
+			if (err) {
+				reject(err);
+			} else {
+				resolve();
+			}
+		});
+	});
+}
@@ -0,0 +1,185 @@
+import { ChildProcess } from 'node:child_process';
+import { randomUUID } from 'node:crypto';
+import type { Readable, Writable } from 'node:stream';
+import { Context } from 'hono';
+import { WSContext, WSEvents } from 'hono/ws';
+import log from '~/utils/log';
+import { dispatchCommand } from './dispatcher';
+
+interface SSHConnection {
+	username: string;
+	hostname: string;
+	port: number;
+}
+
+interface SSHSession {
+	connectionDetails: SSHConnection;
+	connected: boolean;
+	sessionId: string;
+	ws: WSContext;
+}
+
+export function createSSHMultiplexer(proc: ChildProcess): SSHMultiplexer {
+	return new SSHMultiplexer(proc);
+}
+
+export class SSHMultiplexer {
+	private connections: Map<string, SSHSession>;
+	private child: ChildProcess;
+
+	constructor(proc: ChildProcess) {
+		this.connections = new Map();
+		this.child = proc;
+
+		this.handleStdout();
+	}
+
+	// TODO: Determine if we want to allow multiple connections for the same
+	// target or attempt to reuse the existing connection (sounds stupid)
+	private async connect(conn: SSHConnection, ws: WSContext<string>) {
+		const sessionId = randomUUID();
+		const session: SSHSession = {
+			connectionDetails: conn,
+			connected: true,
+			sessionId,
+			ws,
+		};
+
+		log.info('agent', 'Dispatching SSH connection for %s', sessionId);
+		await dispatchCommand(this.child.stdin, {
+			op: 'ssh_conn',
+			payload: {
+				sessionId,
+				...conn,
+			},
+		});
+
+		this.connections.set(sessionId, session);
+		return sessionId;
+	}
+
+	websocketHandler(c: Context): WSEvents<string> {
+		return {
+			onOpen: async (_, ws) => {
+				const { username, hostname, port } = c.req.query();
+				if (!username || !hostname || !port) {
+					ws.close(1008, 'Missing connection parameters');
+					return;
+				}
+
+				const conn: SSHConnection = {
+					username,
+					hostname,
+					port: Number.parseInt(port, 10),
+				};
+
+				try {
+					const sessionId = await this.connect(conn, ws);
+					ws.raw = sessionId;
+					ws.send(JSON.stringify({ status: 'connected', sessionId }));
+				} catch (error) {
+					ws.close(1011, `Connection failed: ${error.message}`);
+				}
+			},
+
+			onMessage: async (event, ws) => {
+				const sessionId = ws.raw;
+				if (!sessionId || !this.connections.has(sessionId)) {
+					ws.close(1008, 'Invalid session ID');
+					return;
+				}
+
+				const session = this.connections.get(sessionId);
+				if (!session || !session.connected) {
+					ws.close(1008, 'Session not connected');
+					return;
+				}
+
+				const encodedFrame = this.encodeFrame(sessionId, event.data);
+				this.child.stdio[3]?.write(encodedFrame);
+			},
+
+			onClose: (_, ws) => {
+				const sessionId = ws.raw;
+				if (sessionId && this.connections.has(sessionId)) {
+					const session = this.connections.get(sessionId);
+					if (session) {
+						session.connected = false;
+						this.connections.delete(sessionId);
+					}
+				}
+			},
+
+			onError: (event, ws) => {
+				const sessionId = ws.raw;
+				if (sessionId && this.connections.has(sessionId)) {
+					const session = this.connections.get(sessionId);
+					if (session) {
+						session.connected = false;
+						this.connections.delete(sessionId);
+					}
+				}
+
+				log.error('agent', 'SSH WebSocket Error with %s', sessionId);
+				console.log(event);
+			},
+		};
+	}
+
+	private encodeFrame(id: string, data: string | Buffer): Buffer {
+		const sid = Buffer.from(id, 'utf8');
+		const payload = Buffer.isBuffer(data) ? data : Buffer.from(data, 'utf8');
+
+		// FIX: include +4 for the payload length
+		const frame = Buffer.alloc(1 + sid.length + 4 + payload.length);
+		frame.writeUint8(sid.length, 0); // 1 byte for sid length
+		sid.copy(frame, 1); // SID
+		frame.writeUint32BE(payload.length, 1 + sid.length); // 4 bytes for payload length
+		payload.copy(frame, 1 + sid.length + 4); // Payload
+
+		return frame;
+	}
+
+	private decodeFrame(frame: Buffer): { id: string; data: Buffer } | undefined {
+		if (frame.length < 5) return;
+
+		const sidLength = frame.readUint8(0);
+		if (frame.length < 1 + sidLength + 4) return;
+
+		const id = frame.slice(1, 1 + sidLength).toString('utf8');
+		const payloadLength = frame.readUint32BE(1 + sidLength);
+		if (frame.length < 1 + sidLength + 4 + payloadLength) return;
+
+		const data = frame.slice(
+			1 + sidLength + 4,
+			1 + sidLength + 4 + payloadLength,
+		);
+
+		return { id, data };
+	}
+
+	private handleStdout() {
+		const stdout = this.child.stdio[4];
+		if (!stdout) {
+			return;
+		}
+
+		stdout.on('data', (bytes) => {
+			console.log(Buffer.from(bytes).toString('utf8'));
+			const decoded = this.decodeFrame(bytes);
+			if (!decoded) {
+				return;
+			}
+
+			const { id, data } = decoded;
+			console.log(id, data);
+			const session = this.connections.get(id);
+			if (!session || !session.connected) {
+				log.warn('agent', 'Received data for disconnected session %s', id);
+				return;
+			}
+
+			session.ws.send(data);
+		});
+	}
+}
@@ -28,6 +28,11 @@ const config = await loadConfig(
 	}),
 );

+const agentManager = await loadAgentSocket(
+	config.integration?.agent,
+	config.headscale.url,
+);
+
 // We also use this file to load anything needed by the react router code.
 // These are usually per-request things that we need access to, like the
 // helper that can issue and revoke cookies.
@@ -56,10 +61,7 @@ const appLoadContext = {
 		config.headscale.tls_cert_path,
 	),

-	agents: await loadAgentSocket(
-		config.integration?.agent,
-		config.headscale.url,
-	),
+	agents: agentManager,
 	integration: await loadIntegration(config.integration),
 	oidc: config.oidc ? await createOidcClient(config.oidc) : undefined,
 };
@@ -85,4 +87,18 @@ export default createHonoServer({
 	listeningListener(info) {
 		log.info('server', 'Running on %s:%s', info.address, info.port);
 	},
+
+	useWebSocket: true,
+	configure: (app, { upgradeWebSocket }) => {
+		if (agentManager === undefined) {
+			return;
+		}
+
+		app.get(
+			'/_ssh_plexer',
+			upgradeWebSocket((c) => {
+				return agentManager.multiplexer!.websocketHandler(c);
+			}),
+		);
+	},
 });
@@ -10,10 +10,12 @@ import {
 } from 'node:fs/promises';
 import { exit } from 'node:process';
 import { createInterface } from 'node:readline';
+import { Readable, Writable } from 'node:stream';
 import { setTimeout } from 'node:timers/promises';
 import { type } from 'arktype';
 import { HostInfo } from '~/types';
 import log from '~/utils/log';
+import { SSHMultiplexer, createSSHMultiplexer } from '../agent/ssh';
 import type { HeadplaneConfig } from '../config/schema';

 interface LogResponse {
@@ -113,6 +115,7 @@ class AgentManager {
 	>;

 	private spawnProcess: ChildProcess | null;
+	multiplexer: SSHMultiplexer | null;
 	private agentId: string | null;

 	constructor(
@@ -124,6 +127,7 @@ class AgentManager {
 		this.config = config;
 		this.headscaleUrl = headscaleUrl;
 		this.spawnProcess = null;
+		this.multiplexer = null;
 		this.agentId = null;
 		this.startAgent();

@@ -184,7 +188,7 @@ class AgentManager {
 		);
 		this.spawnProcess = spawn(this.config.executable_path, [], {
 			detached: false,
-			stdio: ['pipe', 'pipe', 'pipe'],
+			stdio: ['pipe', 'pipe', 'pipe', 'pipe', 'pipe'],
 			env: {
 				HOME: process.env.HOME,
 				HEADPLANE_EMBEDDED: 'true',
@@ -210,6 +214,14 @@ class AgentManager {
 			return;
 		}

+		const sshInput = this.spawnProcess.stdio[3];
+		const sshOutput = this.spawnProcess.stdio[4];
+
+		if (sshInput && sshOutput) {
+			log.info('agent', 'Using SSH multiplexer manager');
+			this.multiplexer = createSSHMultiplexer(this.spawnProcess);
+		}
+
 		const rlStdout = createInterface({
 			input: this.spawnProcess.stdout,
 			crlfDelay: Number.POSITIVE_INFINITY,
@@ -33,7 +33,7 @@ require (
 	github.com/coreos/go-iptables v0.7.1-0.20240112124308-65c67c9f46e6 // indirect
 	github.com/dblohm7/wingoes v0.0.0-20240119213807-a09d6be7affa // indirect
 	github.com/digitalocean/go-smbios v0.0.0-20180907143718-390a4f403a8e // indirect
-	github.com/fxamacker/cbor/v2 v2.6.0 // indirect
+	github.com/fxamacker/cbor/v2 v2.8.0 // indirect
 	github.com/gaissmai/bart v0.11.1 // indirect
 	github.com/go-json-experiment/json v0.0.0-20231102232822-2e55bd4e08b0 // indirect
 	github.com/go-ole/go-ole v1.3.0 // indirect
@@ -76,14 +76,14 @@ require (
 	github.com/vishvananda/netns v0.0.4 // indirect
 	github.com/x448/float16 v0.8.4 // indirect
 	go4.org/netipx v0.0.0-20231129151722-fdeea329fbba // indirect
-	golang.org/x/crypto v0.25.0 // indirect
+	golang.org/x/crypto v0.38.0 // indirect
 	golang.org/x/exp v0.0.0-20240119083558-1b970713d09a // indirect
 	golang.org/x/mod v0.19.0 // indirect
 	golang.org/x/net v0.27.0 // indirect
-	golang.org/x/sync v0.9.0 // indirect
-	golang.org/x/sys v0.27.0 // indirect
-	golang.org/x/term v0.22.0 // indirect
-	golang.org/x/text v0.16.0 // indirect
+	golang.org/x/sync v0.14.0 // indirect
+	golang.org/x/sys v0.33.0 // indirect
+	golang.org/x/term v0.32.0 // indirect
+	golang.org/x/text v0.25.0 // indirect
 	golang.org/x/time v0.5.0 // indirect
 	golang.org/x/tools v0.23.0 // indirect
 	golang.zx2c4.com/wintun v0.0.0-20230126152724-0fa3db229ce2 // indirect
@@ -63,6 +63,8 @@ github.com/frankban/quicktest v1.14.6 h1:7Xjx+VpznH+oBnejlPUj8oUpdxnVs4f8XU8WnHk
 github.com/frankban/quicktest v1.14.6/go.mod h1:4ptaffx2x8+WTWXmUCuVU6aPUX1/Mz7zb5vbUoiM6w0=
 github.com/fxamacker/cbor/v2 v2.6.0 h1:sU6J2usfADwWlYDAFhZBQ6TnLFBHxgesMrQfQgk1tWA=
 github.com/fxamacker/cbor/v2 v2.6.0/go.mod h1:pxXPTn3joSm21Gbwsv0w9OSA2y1HFR9qXEeXQVeNoDQ=
+github.com/fxamacker/cbor/v2 v2.8.0 h1:fFtUGXUzXPHTIUdne5+zzMPTfffl3RD5qYnkY40vtxU=
+github.com/fxamacker/cbor/v2 v2.8.0/go.mod h1:vM4b+DJCtHn+zz7h3FFp/hDAI9WNWCsZj23V5ytsSxQ=
 github.com/gaissmai/bart v0.11.1 h1:5Uv5XwsaFBRo4E5VBcb9TzY8B7zxFf+U7isDxqOrRfc=
 github.com/gaissmai/bart v0.11.1/go.mod h1:KHeYECXQiBjTzQz/om2tqn3sZF1J7hw9m6z41ftj3fg=
 github.com/github/fakeca v0.1.0 h1:Km/MVOFvclqxPM9dZBC4+QE564nU4gz4iZ0D9pMw28I=
@@ -194,6 +196,8 @@ go4.org/netipx v0.0.0-20231129151722-fdeea329fbba h1:0b9z3AuHCjxk0x/opv64kcgZLBs
 go4.org/netipx v0.0.0-20231129151722-fdeea329fbba/go.mod h1:PLyyIXexvUFg3Owu6p/WfdlivPbZJsZdgWZlrGope/Y=
 golang.org/x/crypto v0.25.0 h1:ypSNr+bnYL2YhwoMt2zPxHFmbAN1KZs/njMG3hxUp30=
 golang.org/x/crypto v0.25.0/go.mod h1:T+wALwcMOSE0kXgUAnPAHqTLW+XHgcELELW8VaDgm/M=
+golang.org/x/crypto v0.38.0 h1:jt+WWG8IZlBnVbomuhg2Mdq0+BBQaHbtqHEFEigjUV8=
+golang.org/x/crypto v0.38.0/go.mod h1:MvrbAqul58NNYPKnOra203SB9vpuZW0e+RRZV+Ggqjw=
 golang.org/x/exp v0.0.0-20240119083558-1b970713d09a h1:Q8/wZp0KX97QFTc2ywcOE0YRjZPVIx+MXInMzdvQqcA=
 golang.org/x/exp v0.0.0-20240119083558-1b970713d09a/go.mod h1:idGWGoKP1toJGkd5/ig9ZLuPcZBC3ewk7SzmH0uou08=
 golang.org/x/exp/typeparams v0.0.0-20240314144324-c7f7c6466f7f h1:phY1HzDcf18Aq9A8KkmRtY9WvOFIxN8wgfvy6Zm1DV8=
@@ -207,6 +211,8 @@ golang.org/x/net v0.27.0/go.mod h1:dDi0PyhWNoiUOrAS8uXv/vnScO4wnHQO4mj9fn/RytE=
 golang.org/x/sync v0.0.0-20210220032951-036812b2e83c/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.9.0 h1:fEo0HyrW1GIgZdpbhCRO0PkJajUS5H9IFUztCgEo2jQ=
 golang.org/x/sync v0.9.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
+golang.org/x/sync v0.14.0 h1:woo0S4Yywslg6hp4eUFjTVOyKt0RookbpAHG4c1HmhQ=
+golang.org/x/sync v0.14.0/go.mod h1:1dzgHSNfp02xaA81J2MS99Qcpr2w7fw1gpm99rleRqA=
 golang.org/x/sys v0.0.0-20200217220822-9197077df867/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200728102440-3e129f6d46b1/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20220622161953-175b2fd9d664/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
@@ -216,10 +222,16 @@ golang.org/x/sys v0.4.1-0.20230131160137-e7d7f63158de/go.mod h1:oPkhp1MJrh7nUepC
 golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.27.0 h1:wBqf8DvsY9Y/2P8gAfPDEYNuS30J4lPHJxXSb/nJZ+s=
 golang.org/x/sys v0.27.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/sys v0.33.0 h1:q3i8TbbEz+JRD9ywIRlyRAQbM0qF7hu24q3teo2hbuw=
+golang.org/x/sys v0.33.0/go.mod h1:BJP2sWEmIv4KK5OTEluFJCKSidICx8ciO85XgH3Ak8k=
 golang.org/x/term v0.22.0 h1:BbsgPEJULsl2fV/AT3v15Mjva5yXKQDyKf+TbDz7QJk=
 golang.org/x/term v0.22.0/go.mod h1:F3qCibpT5AMpCRfhfT53vVJwhLtIVHhB9XDjfFvnMI4=
+golang.org/x/term v0.32.0 h1:DR4lr0TjUs3epypdhTOkMmuF5CDFJ/8pOnbzMZPQ7bg=
+golang.org/x/term v0.32.0/go.mod h1:uZG1FhGx848Sqfsq4/DlJr3xGGsYMu/L5GW4abiaEPQ=
 golang.org/x/text v0.16.0 h1:a94ExnEXNtEwYLGJSIUxnWoxoRz/ZcCsV63ROupILh4=
 golang.org/x/text v0.16.0/go.mod h1:GhwF1Be+LQoKShO3cGOHzqOgRrGaYc9AvblQOmPVHnI=
+golang.org/x/text v0.25.0 h1:qVyWApTSYLk/drJRO5mDlNYskwQznZmkpV2c8q9zls4=
+golang.org/x/text v0.25.0/go.mod h1:WEdwpYrmk1qmdHvhkSTNPm3app7v4rsT8F2UD6+VHIA=
 golang.org/x/time v0.5.0 h1:o7cqy6amK/52YcAKIPlM3a+Fpj35zvRj2TP+e1xFSfk=
 golang.org/x/time v0.5.0/go.mod h1:3BpzKBy/shNhVucY/MWOyx10tF3SFh9QdLuxbVysPQM=
 golang.org/x/tools v0.23.0 h1:SGsXPZ+2l4JsgaCKkx+FQ9YZ5XEtA1GZYuoDjenLjvg=
@@ -29,6 +29,7 @@
 		"@uiw/codemirror-theme-xcode": "^4.23.12",
 		"@uiw/react-codemirror": "^4.23.12",
 		"arktype": "^2.1.20",
+		"cbor2": "^2.0.1",
 		"clsx": "^2.1.1",
 		"dotenv": "^16.5.0",
 		"isbot": "^5.1.28",
@@ -55,6 +56,7 @@
 		"@react-router/dev": "^7.6.1",
 		"@tailwindcss/vite": "^4.1.8",
 		"@types/websocket": "^1.0.10",
+		"hono": "^4.7.10",
 		"lefthook": "^1.11.13",
 		"postcss": "^8.5.4",
 		"react-router-dom": "^7.6.1",
@@ -64,6 +64,9 @@ importers:
      arktype:
        specifier: ^2.1.20
        version: 2.1.20
+      cbor2:
+        specifier: ^2.0.1
+        version: 2.0.1
      clsx:
        specifier: ^2.1.1
        version: 2.1.1
@@ -137,6 +140,9 @@ importers:
      '@types/websocket':
        specifier: ^1.0.10
        version: 1.0.10
+      hono:
+        specifier: ^4.7.10
+        version: 4.7.10
      lefthook:
        specifier: ^1.11.13
        version: 1.11.13
@@ -406,6 +412,10 @@ packages:
  '@codemirror/view@6.36.8':
    resolution: {integrity: sha512-yoRo4f+FdnD01fFt4XpfpMCcCAo9QvZOtbrXExn4SqzH32YC6LgzqxfLZw/r6Ge65xyY03mK/UfUqrVw1gFiFg==}

+  '@cto.af/wtf8@0.0.2':
+    resolution: {integrity: sha512-ATm4UQiKrdm5GnU6BvIwUDN+LDEtt23zuzKFpnfDT59ULAd0aMYm/nSFzbSO02garLcXumRC13PzNfa7BsfvSg==}
+    engines: {node: '>=20'}
+
  '@dnd-kit/accessibility@3.1.1':
    resolution: {integrity: sha512-2P+YgaXF+gRsIihwwY1gCsQSYnu9Zyj2py8kY5fFvUM1qm2WA2u639R6YNVfU4GWr+ZM5mqEsfHZZLoRONbemw==}
    peerDependencies:
@@ -1692,6 +1702,10 @@ packages:
  caniuse-lite@1.0.30001718:
    resolution: {integrity: sha512-AflseV1ahcSunK53NfEs9gFWgOEmzr0f+kaMFA4xiLZlr9Hzt7HxcSpIFcnNCUkz6R6dWKa54rUz3HUmI3nVcw==}

+  cbor2@2.0.1:
+    resolution: {integrity: sha512-9bE8+tueGxONyxpttNKkAKKcGVtAPeoSJ64AjVTTjEuBOuRaeeP76EN9BbmQqkz1ZeTP0QPvksNBKwvEutIUzQ==}
+    engines: {node: '>=20'}
+
  chokidar@4.0.3:
    resolution: {integrity: sha512-Qgzu8kfBvo+cA4962jnP1KkS6Dop5NS6g7R5LFYJr4b8Ub94PPQXUksCw9PvXoeXPRRddRNC5C1JQUR2SMGtnA==}
    engines: {node: '>= 14.16.0'}
@@ -1924,8 +1938,8 @@ packages:
    resolution: {integrity: sha512-0hJU9SCPvmMzIBdZFqNPXWa6dqh7WdH0cII9y+CyS8rG3nL48Bclra9HmKhVVUHyPWNH5Y7xDwAB7bfgSjkUMQ==}
    engines: {node: '>= 0.4'}

-  hono@4.7.6:
-    resolution: {integrity: sha512-564rVzELU+9BRqqx5k8sT2NFwGD3I3Vifdb6P7CmM6FiarOSY+fDC+6B+k9wcCb86ReoayteZP2ki0cRLN1jbw==}
+  hono@4.7.10:
+    resolution: {integrity: sha512-QkACju9MiN59CKSY5JsGZCYmPZkA6sIW6OFCUp7qDjZu6S6KHtJHhAc9Uy9mV9F8PJ1/HQ3ybZF2yjCa/73fvQ==}
    engines: {node: '>=16.9.0'}

  hosted-git-info@6.1.3:
@@ -3138,6 +3152,8 @@ snapshots:
      style-mod: 4.1.2
      w3c-keyname: 2.2.8

+  '@cto.af/wtf8@0.0.2': {}
+
  '@dnd-kit/accessibility@3.1.1(react@19.1.0)':
    dependencies:
      react: 19.1.0
@@ -3275,23 +3291,23 @@ snapshots:
    dependencies:
      tslib: 2.8.1

-  '@hono/node-server@1.14.0(hono@4.7.6)':
+  '@hono/node-server@1.14.0(hono@4.7.10)':
    dependencies:
-      hono: 4.7.6
+      hono: 4.7.10

-  '@hono/node-ws@1.1.1(@hono/node-server@1.14.0(hono@4.7.6))(bufferutil@4.0.9)(hono@4.7.6)(utf-8-validate@5.0.10)':
+  '@hono/node-ws@1.1.1(@hono/node-server@1.14.0(hono@4.7.10))(bufferutil@4.0.9)(hono@4.7.10)(utf-8-validate@5.0.10)':
    dependencies:
-      '@hono/node-server': 1.14.0(hono@4.7.6)
-      hono: 4.7.6
+      '@hono/node-server': 1.14.0(hono@4.7.10)
+      hono: 4.7.10
      ws: 8.18.1(bufferutil@4.0.9)(utf-8-validate@5.0.10)
    transitivePeerDependencies:
      - bufferutil
      - utf-8-validate

-  '@hono/vite-dev-server@0.19.0(hono@4.7.6)':
+  '@hono/vite-dev-server@0.19.0(hono@4.7.10)':
    dependencies:
-      '@hono/node-server': 1.14.0(hono@4.7.6)
-      hono: 4.7.6
+      '@hono/node-server': 1.14.0(hono@4.7.10)
+      hono: 4.7.10
      minimatch: 9.0.5

  '@internationalized/date@3.8.1':
@@ -4801,6 +4817,10 @@ snapshots:

  caniuse-lite@1.0.30001718: {}

+  cbor2@2.0.1:
+    dependencies:
+      '@cto.af/wtf8': 0.0.2
+
  chokidar@4.0.3:
    dependencies:
      readdirp: 4.1.2
@@ -5029,7 +5049,7 @@ snapshots:
    dependencies:
      function-bind: 1.1.2

-  hono@4.7.6: {}
+  hono@4.7.10: {}

  hosted-git-info@6.1.3:
    dependencies:
@@ -5423,12 +5443,12 @@ snapshots:
  react-router-hono-server@2.13.0(patch_hash=6549978df41006e07f1335bfe4ca86224ea36ed40d3f08dfef33143bad54005c)(@react-router/dev@7.6.1(@types/node@22.15.24)(jiti@2.4.2)(lightningcss@1.30.1)(react-router@7.6.1(react-dom@19.1.0(react@19.1.0))(react@19.1.0))(terser@5.39.0)(tsx@4.19.4)(typescript@5.8.3)(vite@6.3.5(@types/node@22.15.24)(jiti@2.4.2)(lightningcss@1.30.1)(terser@5.39.0)(tsx@4.19.4)(yaml@2.8.0))(yaml@2.8.0))(@types/react@19.1.6)(bufferutil@4.0.9)(react-router@7.6.1(react-dom@19.1.0(react@19.1.0))(react@19.1.0))(utf-8-validate@5.0.10)(vite@6.3.5(@types/node@22.15.24)(jiti@2.4.2)(lightningcss@1.30.1)(terser@5.39.0)(tsx@4.19.4)(yaml@2.8.0)):
    dependencies:
      '@drizzle-team/brocli': 0.11.0
-      '@hono/node-server': 1.14.0(hono@4.7.6)
-      '@hono/node-ws': 1.1.1(@hono/node-server@1.14.0(hono@4.7.6))(bufferutil@4.0.9)(hono@4.7.6)(utf-8-validate@5.0.10)
-      '@hono/vite-dev-server': 0.19.0(hono@4.7.6)
+      '@hono/node-server': 1.14.0(hono@4.7.10)
+      '@hono/node-ws': 1.1.1(@hono/node-server@1.14.0(hono@4.7.10))(bufferutil@4.0.9)(hono@4.7.10)(utf-8-validate@5.0.10)
+      '@hono/vite-dev-server': 0.19.0(hono@4.7.10)
      '@react-router/dev': 7.6.1(@types/node@22.15.24)(jiti@2.4.2)(lightningcss@1.30.1)(react-router@7.6.1(react-dom@19.1.0(react@19.1.0))(react@19.1.0))(terser@5.39.0)(tsx@4.19.4)(typescript@5.8.3)(vite@6.3.5(@types/node@22.15.24)(jiti@2.4.2)(lightningcss@1.30.1)(terser@5.39.0)(tsx@4.19.4)(yaml@2.8.0))(yaml@2.8.0)
      '@types/react': 19.1.6
-      hono: 4.7.6
+      hono: 4.7.10
      react-router: 7.6.1(react-dom@19.1.0(react@19.1.0))(react@19.1.0)
      vite: 6.3.5(@types/node@22.15.24)(jiti@2.4.2)(lightningcss@1.30.1)(terser@5.39.0)(tsx@4.19.4)(yaml@2.8.0)
    transitivePeerDependencies: