[client] Keep the iOS ConnectionListener source-compatible

Adding OnStateChanged to the gomobile interface forces every Swift
implementation to grow the method before the app builds again. Drop it
from the iOS binding for now — the adapter satisfies the internal
listener with a no-op and the legacy per-state callbacks keep firing —
so the app upgrades on its own schedule. The state constants stay
exported for that follow-up.

client/ios/NetBirdSDK/connection_listener.go

@@ -6,9 +6,9 @@ import (
 	"github.com/netbirdio/netbird/client/internal/peer"
 )
 
-// Client state values delivered via ConnectionListener.OnStateChanged,
-// re-exported as basic constants so gomobile emits them into the generated
-// bindings. They mirror peer.ClientState*: append-only, never reorder.
+// Client state values, re-exported as basic constants so gomobile emits them
+// into the generated bindings. They mirror peer.ClientState*: append-only,
+// never reorder.
 const (
 	ClientStateDisconnected  = int(peer.ClientStateDisconnected)
 	ClientStateConnected     = int(peer.ClientStateConnected)
@@ -17,11 +17,13 @@ const (
 	ClientStateNoNetwork     = int(peer.ClientStateNoNetwork)
 )
 
-// ConnectionListener export internal Listener for mobile. It mirrors
-// peer.Listener with OnStateChanged taking a plain int (one of the
-// ClientState* constants), because gomobile cannot bind named types.
+// ConnectionListener export internal Listener for mobile.
+//
+// It intentionally lacks OnStateChanged for now: adding a method to a gomobile
+// interface breaks every Swift implementation, so the iOS app keeps building
+// against the legacy per-state callbacks. A follow-up will extend it together
+// with the app.
 type ConnectionListener interface {
-	OnStateChanged(state int)
 	OnConnected()
 	OnDisconnected()
 	OnConnecting()
@@ -31,11 +33,11 @@ type ConnectionListener interface {
 }
 
 // connectionListenerAdapter adapts the gomobile-facing ConnectionListener to
-// peer.Listener, converting the typed state to the int the binding carries.
+// peer.Listener.
 type connectionListenerAdapter struct {
 	ConnectionListener
 }
 
-func (a connectionListenerAdapter) OnStateChanged(state peer.ClientState) {
-	a.ConnectionListener.OnStateChanged(int(state))
-}
+// OnStateChanged is dropped on iOS until the app adopts the state callback;
+// the legacy per-state callbacks continue to fire.
+func (a connectionListenerAdapter) OnStateChanged(peer.ClientState) {}

client/netsweep/netsweep.go

@@ -0,0 +1,119 @@
+// Package netsweep cuts network-bound activity when the OS switches networks:
+// a sweep closes the registered connections and aborts the in-flight dials, so
+// their owners redial immediately instead of waiting for the old sockets to
+// time out.
+//
+// A nil *Sweeper disables everything: all methods are nil-safe no-ops.
+package netsweep
+
+import (
+	"context"
+	"net"
+	"sync"
+
+	log "github.com/sirupsen/logrus"
+)
+
+// sweptConn deregisters itself from the sweeper when closed.
+type sweptConn struct {
+	net.Conn
+	sweeper *Sweeper
+	id      uint64
+}
+
+func (c *sweptConn) Close() error {
+	c.sweeper.deregister(c.id)
+	return c.Conn.Close()
+}
+
+// Sweeper registers live connections and in-flight dials so Sweep can cut
+// everything that started before the network changed.
+type Sweeper struct {
+	mu     sync.Mutex
+	conns  map[uint64]net.Conn
+	dials  map[uint64]context.CancelFunc
+	nextID uint64
+}
+
+// New creates an empty sweeper.
+func New() *Sweeper {
+	return &Sweeper{
+		conns: make(map[uint64]net.Conn),
+		dials: make(map[uint64]context.CancelFunc),
+	}
+}
+
+// WrapConn registers conn and returns a wrapper that deregisters it on Close.
+func (s *Sweeper) WrapConn(conn net.Conn) net.Conn {
+	if s == nil {
+		return conn
+	}
+
+	s.mu.Lock()
+	id := s.nextID
+	s.nextID++
+	s.conns[id] = conn
+	s.mu.Unlock()
+
+	return &sweptConn{Conn: conn, sweeper: s, id: id}
+}
+
+// WrapDialContext derives a context that Sweep cancels. The returned release
+// must be called when the dial finishes, typically deferred.
+func (s *Sweeper) WrapDialContext(ctx context.Context) (context.Context, context.CancelFunc) {
+	if s == nil {
+		return ctx, func() {}
+	}
+
+	ctx, cancel := context.WithCancel(ctx)
+
+	s.mu.Lock()
+	id := s.nextID
+	s.nextID++
+	s.dials[id] = cancel
+	s.mu.Unlock()
+
+	release := func() {
+		s.mu.Lock()
+		delete(s.dials, id)
+		s.mu.Unlock()
+		cancel()
+	}
+	return ctx, release
+}
+
+// Sweep closes every registered connection, aborts every in-flight dial, and
+// returns how many connections it closed.
+func (s *Sweeper) Sweep() int {
+	if s == nil {
+		return 0
+	}
+
+	s.mu.Lock()
+	conns := s.conns
+	dials := s.dials
+	s.conns = make(map[uint64]net.Conn)
+	s.dials = make(map[uint64]context.CancelFunc)
+	s.mu.Unlock()
+
+	if len(dials) > 0 {
+		log.Debugf("aborting %d in-flight dials", len(dials))
+		for _, cancel := range dials {
+			cancel()
+		}
+	}
+
+	for _, conn := range conns {
+		log.Debugf("sweeping connection %s -> %s", conn.LocalAddr(), conn.RemoteAddr())
+		if err := conn.Close(); err != nil {
+			log.Debugf("swept connection close error: %v", err)
+		}
+	}
+	return len(conns)
+}
+
+func (s *Sweeper) deregister(id uint64) {
+	s.mu.Lock()
+	delete(s.conns, id)
+	s.mu.Unlock()
+}

client/netsweep/netsweep_test.go

@@ -0,0 +1,119 @@
+package netsweep
+
+import (
+	"context"
+	"net"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestSweepClosesRegisteredConns(t *testing.T) {
+	sweeper := New()
+
+	c1 := sweeper.WrapConn(connPair(t))
+	c2 := sweeper.WrapConn(connPair(t))
+
+	assert.Equal(t, 2, sweeper.Sweep(), "both live connections should be closed")
+
+	// The wrappers must report closed now.
+	buf := make([]byte, 1)
+	_, err := c1.Read(buf)
+	assert.Error(t, err, "first connection should be unusable after the sweep")
+	_, err = c2.Read(buf)
+	assert.Error(t, err, "second connection should be unusable after the sweep")
+
+	assert.Equal(t, 0, sweeper.Sweep(), "second sweep should find nothing")
+}
+
+func TestCloseDeregisters(t *testing.T) {
+	sweeper := New()
+
+	conn := sweeper.WrapConn(connPair(t))
+	require.NoError(t, conn.Close())
+
+	assert.Equal(t, 0, sweeper.Sweep(), "closed connection must leave the registry")
+}
+
+func TestCloseIsIdempotent(t *testing.T) {
+	sweeper := New()
+
+	conn := sweeper.WrapConn(connPair(t))
+	require.NoError(t, conn.Close())
+	assert.Error(t, conn.Close(), "double close surfaces the underlying error but must not panic")
+}
+
+func TestSweepOnlyAffectsOlderConns(t *testing.T) {
+	sweeper := New()
+
+	_ = sweeper.WrapConn(connPair(t))
+	assert.Equal(t, 1, sweeper.Sweep())
+
+	// A connection dialed after the sweep must survive until the next one.
+	_ = sweeper.WrapConn(connPair(t))
+	assert.Equal(t, 1, sweeper.Sweep(), "post-sweep connection belongs to the next sweep")
+}
+
+func TestSweepAbortsInFlightDials(t *testing.T) {
+	sweeper := New()
+
+	dialCtx, release := sweeper.WrapDialContext(context.Background())
+	defer release()
+
+	sweeper.Sweep()
+
+	assert.ErrorIs(t, dialCtx.Err(), context.Canceled, "sweep must cancel the in-flight dial context")
+}
+
+func TestReleasedDialIsNotAborted(t *testing.T) {
+	sweeper := New()
+
+	// Simulate a dial that finished before the sweep.
+	_, release := sweeper.WrapDialContext(context.Background())
+	release()
+
+	// A dial still in flight during the sweep.
+	pendingCtx, pendingRelease := sweeper.WrapDialContext(context.Background())
+	defer pendingRelease()
+
+	sweeper.Sweep()
+	assert.ErrorIs(t, pendingCtx.Err(), context.Canceled, "pending dial must be aborted")
+}
+
+func TestNilSweeperIsNoop(t *testing.T) {
+	var sweeper *Sweeper
+
+	conn := connPair(t)
+	assert.Equal(t, conn, sweeper.WrapConn(conn), "nil sweeper must return the conn unchanged")
+	assert.Equal(t, 0, sweeper.Sweep(), "nil sweeper closes nothing")
+
+	ctx, release := sweeper.WrapDialContext(context.Background())
+	release()
+	assert.NoError(t, ctx.Err(), "nil sweeper must not cancel the dial context")
+}
+
+// connPair dials a loopback TCP connection against a throwaway listener.
+func connPair(t *testing.T) net.Conn {
+	t.Helper()
+
+	l, err := net.Listen("tcp", "127.0.0.1:0")
+	require.NoError(t, err)
+	t.Cleanup(func() {
+		if err := l.Close(); err != nil {
+			t.Logf("listener close error: %v", err)
+		}
+	})
+
+	go func() {
+		conn, err := l.Accept()
+		if err != nil {
+			return
+		}
+		_ = conn.Close()
+	}()
+
+	conn, err := net.Dial("tcp", l.Addr().String())
+	require.NoError(t, err)
+	return conn
+}