Revert "Introduces a forced WG handshake on initial MLKEM bootstrap."

This reverts commit b5a72eca65.

client/internal/peer/conn.go

@@ -738,35 +738,6 @@ func (conn *Conn) RequestReoffer() {
 	}
 }
 
-// ForcePQRehandshake makes WireGuard adopt a freshly bootstrapped post-quantum PSK on
-// an already-up session. The KEM exchange can complete after the WG endpoint was
-// configured (a race between the KEM and the relay/ICE connection coming up), so the
-// live session may be keyed with a pre-PQ key (the strict sentinel, or the ordinary
-// key in permissive mode); SetPresharedKey only updates config, not the running
-// session. Removing and re-adding the peer forces a fresh handshake that uses the real
-// PSK. No-op if not connected yet (the upcoming endpoint config will pull the PSK) or
-// if no PSK exists (a non-PQ peer stays fail-closed).
-func (conn *Conn) ForcePQRehandshake() {
-	conn.mu.Lock()
-	defer conn.mu.Unlock()
-
-	if conn.ctx.Err() != nil || conn.config.PQ == nil {
-		return
-	}
-	psk, ok := conn.config.PQ.PSK(conn.config.Key)
-	if !ok {
-		return
-	}
-	if conn.currentConnPriority == conntype.None {
-		return
-	}
-	conn.Log.Debugf("pqkem: bootstrap PSK ready, forcing WireGuard re-handshake to adopt it")
-	wgPsk := wgtypes.Key(psk)
-	if err := conn.endpointUpdater.ForceRehandshake(&wgPsk); err != nil {
-		conn.Log.Warnf("pqkem: force re-handshake failed: %v", err)
-	}
-}
-
 func (conn *Conn) onWGDisconnected(watcherCtx context.Context) {
 	conn.mu.Lock()
 	defer conn.mu.Unlock()

client/internal/peer/endpoint.go

@@ -20,13 +20,10 @@ type EndpointUpdater struct {
 	wgConfig  WgConfig
 	initiator bool
 
-	// mu protects cancelFunc and lastEndpoint
+	// mu protects cancelFunc
 	mu         sync.Mutex
 	cancelFunc func()
 	updateWg   sync.WaitGroup
-	// lastEndpoint is the most recent non-nil endpoint applied to the peer, used to
-	// re-add it on a forced re-handshake (ForceRehandshake).
-	lastEndpoint *net.UDPAddr
 }
 
 func NewEndpointUpdater(log *logrus.Entry, wgConfig WgConfig, initiator bool) *EndpointUpdater {
@@ -41,10 +38,6 @@ func (e *EndpointUpdater) ConfigureWGEndpoint(addr *net.UDPAddr, presharedKey *w
 	e.mu.Lock()
 	defer e.mu.Unlock()
 
-	if addr != nil {
-		e.lastEndpoint = addr
-	}
-
 	if e.initiator {
 		e.log.Debugf("configure up WireGuard as initiator")
 		return e.configureAsInitiator(addr, presharedKey)
@@ -58,36 +51,12 @@ func (e *EndpointUpdater) SwitchWGEndpoint(addr *net.UDPAddr, presharedKey *wgty
 	e.mu.Lock()
 	defer e.mu.Unlock()
 
-	if addr != nil {
-		e.lastEndpoint = addr
-	}
-
 	// prevent to run new update while cancel the previous update
 	e.waitForCloseTheDelayedUpdate()
 
 	return e.updateWireGuardPeer(addr, presharedKey)
 }
 
-// ForceRehandshake removes and re-adds the peer so WireGuard drops the current session
-// and negotiates a fresh one with the given PSK. Used when a post-quantum PSK is
-// bootstrapped after the session already came up on a pre-PQ key. No-op if no endpoint
-// has been applied yet (the pending config will pull the PSK itself).
-func (e *EndpointUpdater) ForceRehandshake(presharedKey *wgtypes.Key) error {
-	e.mu.Lock()
-	defer e.mu.Unlock()
-
-	if e.lastEndpoint == nil {
-		return nil
-	}
-	// Cancel any pending delayed responder update: it carries the stale pre-PQ key and
-	// would otherwise re-poison the session after we reset it.
-	e.waitForCloseTheDelayedUpdate()
-	if err := e.wgConfig.WgInterface.RemovePeer(e.wgConfig.RemoteKey); err != nil {
-		return err
-	}
-	return e.updateWireGuardPeer(e.lastEndpoint, presharedKey)
-}
-
 func (e *EndpointUpdater) RemoveWgPeer() error {
 	e.mu.Lock()
 	defer e.mu.Unlock()