[client,management] Rewrite the SSH feature (#4015)

client/embed/embed.go

@@ -18,12 +18,16 @@ import (
 	"github.com/netbirdio/netbird/client/internal"
 	"github.com/netbirdio/netbird/client/internal/peer"
 	"github.com/netbirdio/netbird/client/internal/profilemanager"
+	sshcommon "github.com/netbirdio/netbird/client/ssh"
 	"github.com/netbirdio/netbird/client/system"
 )
 
-var ErrClientAlreadyStarted = errors.New("client already started")
-var ErrClientNotStarted = errors.New("client not started")
-var ErrConfigNotInitialized = errors.New("config not initialized")
+var (
+	ErrClientAlreadyStarted = errors.New("client already started")
+	ErrClientNotStarted     = errors.New("client not started")
+	ErrEngineNotStarted     = errors.New("engine not started")
+	ErrConfigNotInitialized = errors.New("config not initialized")
+)
 
 // Client manages a netbird embedded client instance.
 type Client struct {
@@ -238,17 +242,9 @@ func (c *Client) GetConfig() (profilemanager.Config, error) {
 // Dial dials a network address in the netbird network.
 // Not applicable if the userspace networking mode is disabled.
 func (c *Client) Dial(ctx context.Context, network, address string) (net.Conn, error) {
-	c.mu.Lock()
-	connect := c.connect
-	if connect == nil {
-		c.mu.Unlock()
-		return nil, ErrClientNotStarted
-	}
-	c.mu.Unlock()
-
-	engine := connect.Engine()
-	if engine == nil {
-		return nil, errors.New("engine not started")
+	engine, err := c.getEngine()
+	if err != nil {
+		return nil, err
 	}
 
 	nsnet, err := engine.GetNet()
@@ -259,6 +255,11 @@ func (c *Client) Dial(ctx context.Context, network, address string) (net.Conn, e
 	return nsnet.DialContext(ctx, network, address)
 }
 
+// DialContext dials a network address in the netbird network with context
+func (c *Client) DialContext(ctx context.Context, network, address string) (net.Conn, error) {
+	return c.Dial(ctx, network, address)
+}
+
 // ListenTCP listens on the given address in the netbird network.
 // Not applicable if the userspace networking mode is disabled.
 func (c *Client) ListenTCP(address string) (net.Listener, error) {
@@ -314,18 +315,47 @@ func (c *Client) NewHTTPClient() *http.Client {
 	}
 }
 
-func (c *Client) getNet() (*wgnetstack.Net, netip.Addr, error) {
+// VerifySSHHostKey verifies an SSH host key against stored peer keys.
+// Returns nil if the key matches, ErrPeerNotFound if peer is not in network,
+// ErrNoStoredKey if peer has no stored key, or an error for verification failures.
+func (c *Client) VerifySSHHostKey(peerAddress string, key []byte) error {
+	engine, err := c.getEngine()
+	if err != nil {
+		return err
+	}
+
+	storedKey, found := engine.GetPeerSSHKey(peerAddress)
+	if !found {
+		return sshcommon.ErrPeerNotFound
+	}
+
+	return sshcommon.VerifyHostKey(storedKey, key, peerAddress)
+}
+
+// getEngine safely retrieves the engine from the client with proper locking.
+// Returns ErrClientNotStarted if the client is not started.
+// Returns ErrEngineNotStarted if the engine is not available.
+func (c *Client) getEngine() (*internal.Engine, error) {
 	c.mu.Lock()
 	connect := c.connect
-	if connect == nil {
-		c.mu.Unlock()
-		return nil, netip.Addr{}, errors.New("client not started")
-	}
 	c.mu.Unlock()
 
+	if connect == nil {
+		return nil, ErrClientNotStarted
+	}
+
 	engine := connect.Engine()
 	if engine == nil {
-		return nil, netip.Addr{}, errors.New("engine not started")
+		return nil, ErrEngineNotStarted
+	}
+
+	return engine, nil
+}
+
+func (c *Client) getNet() (*wgnetstack.Net, netip.Addr, error) {
+	engine, err := c.getEngine()
+	if err != nil {
+		return nil, netip.Addr{}, err
 	}
 
 	addr, err := engine.Address()