[client] Cancel ServeDNS-path mgmt resolve on server Stop

awaitPendingResolve resolved on context.Background(), so a resolve
triggered by an incoming query kept running to dnsTimeout after Stop,
making the DNS listener's ShutdownContext wait it out. Give the Resolver
the server-lifetime ctx and use it there so Stop cancels the resolve.

client/internal/dns/mgmt/mgmt.go

@@ -57,6 +57,9 @@ type pendingEntry struct{}
 // Resolver caches critical NetBird infrastructure domains.
 // records, refreshing, pending, mgmtDomain and serverDomains are all guarded by mutex.
 type Resolver struct {
+	// ctx is the server-lifetime context for background resolves.
+	ctx context.Context
+
 	records       map[dns.Question]*cachedRecord
 	mgmtDomain    *domain.Domain
 	serverDomains *dnsconfig.ServerDomains
@@ -85,8 +88,9 @@ type Resolver struct {
 }
 
 // NewResolver creates a new management domains cache resolver.
-func NewResolver() *Resolver {
+func NewResolver(ctx context.Context) *Resolver {
 	return &Resolver{
+		ctx:        ctx,
 		records:    make(map[dns.Question]*cachedRecord),
 		refreshing: make(map[dns.Question]*atomic.Bool),
 		pending:    make(map[string]pendingEntry),
@@ -613,7 +617,7 @@ func (m *Resolver) awaitPendingResolve(dnsName string) bool {
 
 	ch := m.resolveGroup.DoChan(key, func() (any, error) {
 		defer m.clearPending(dnsName)
-		if err := m.AddDomain(context.Background(), d); err != nil {
+		if err := m.AddDomain(m.ctx, d); err != nil {
 			return struct{}{}, err
 		}
 		return struct{}{}, nil

client/internal/dns/mgmt/mgmt_refresh_test.go

@@ -130,7 +130,7 @@ func TestResolver_CacheTTLGatesRefresh(t *testing.T) {
 	q := dns.Question{Name: "mgmt.example.com.", Qtype: dns.TypeA, Qclass: dns.ClassINET}
 
 	t.Run("short TTL treats entry as stale and refreshes", func(t *testing.T) {
-		r := NewResolver()
+		r := NewResolver(context.Background())
 		r.cacheTTL = 10 * time.Millisecond
 		chain := newFakeChain()
 		chain.setAnswer(q.Name, dns.TypeA, "10.0.0.2")
@@ -146,7 +146,7 @@ func TestResolver_CacheTTLGatesRefresh(t *testing.T) {
 	})
 
 	t.Run("long TTL keeps entry fresh and skips refresh", func(t *testing.T) {
-		r := NewResolver()
+		r := NewResolver(context.Background())
 		r.cacheTTL = time.Hour
 		chain := newFakeChain()
 		chain.setAnswer(q.Name, dns.TypeA, "10.0.0.2")
@@ -162,7 +162,7 @@ func TestResolver_CacheTTLGatesRefresh(t *testing.T) {
 }
 
 func TestResolver_ServeFresh_NoRefresh(t *testing.T) {
-	r := NewResolver()
+	r := NewResolver(context.Background())
 	chain := newFakeChain()
 	chain.setAnswer("mgmt.example.com.", dns.TypeA, "10.0.0.2")
 	r.SetChainResolver(chain, 50)
@@ -183,7 +183,7 @@ func TestResolver_ServeFresh_NoRefresh(t *testing.T) {
 }
 
 func TestResolver_StaleTriggersAsyncRefresh(t *testing.T) {
-	r := NewResolver()
+	r := NewResolver(context.Background())
 	chain := newFakeChain()
 	chain.setAnswer("mgmt.example.com.", dns.TypeA, "10.0.0.2")
 	r.SetChainResolver(chain, 50)
@@ -213,7 +213,7 @@ func TestResolver_StaleTriggersAsyncRefresh(t *testing.T) {
 }
 
 func TestResolver_ConcurrentStaleHitsCollapseRefresh(t *testing.T) {
-	r := NewResolver()
+	r := NewResolver(context.Background())
 	chain := newFakeChain()
 	chain.setAnswer("mgmt.example.com.", dns.TypeA, "10.0.0.2")
 
@@ -262,7 +262,7 @@ func TestResolver_ConcurrentStaleHitsCollapseRefresh(t *testing.T) {
 }
 
 func TestResolver_RefreshFailureArmsBackoff(t *testing.T) {
-	r := NewResolver()
+	r := NewResolver(context.Background())
 	chain := newFakeChain()
 	chain.err = errors.New("boom")
 	r.SetChainResolver(chain, 50)
@@ -299,7 +299,7 @@ func TestResolver_RefreshFailureArmsBackoff(t *testing.T) {
 }
 
 func TestResolver_NoRootHandler_SkipsChain(t *testing.T) {
-	r := NewResolver()
+	r := NewResolver(context.Background())
 	chain := newFakeChain()
 	chain.hasRoot = false
 	chain.setAnswer("mgmt.example.com.", dns.TypeA, "10.0.0.2")
@@ -320,7 +320,7 @@ func TestResolver_ServeDuringRefreshSetsLoopFlag(t *testing.T) {
 	// ServeDNS being invoked for a question while a refresh for that question
 	// is inflight indicates a resolver loop (OS resolver sent the recursive
 	// query back to us). The inflightRefresh.loopLoggedOnce flag must be set.
-	r := NewResolver()
+	r := NewResolver(context.Background())
 
 	q := dns.Question{Name: "mgmt.example.com.", Qtype: dns.TypeA, Qclass: dns.ClassINET}
 	r.records[q] = &cachedRecord{
@@ -346,7 +346,7 @@ func TestResolver_ServeDuringRefreshSetsLoopFlag(t *testing.T) {
 }
 
 func TestResolver_LoopFlagOnlyTrippedOncePerRefresh(t *testing.T) {
-	r := NewResolver()
+	r := NewResolver(context.Background())
 
 	q := dns.Question{Name: "mgmt.example.com.", Qtype: dns.TypeA, Qclass: dns.ClassINET}
 	r.records[q] = &cachedRecord{
@@ -373,7 +373,7 @@ func TestResolver_LoopFlagOnlyTrippedOncePerRefresh(t *testing.T) {
 }
 
 func TestResolver_NoLoopFlagWhenNotRefreshing(t *testing.T) {
-	r := NewResolver()
+	r := NewResolver(context.Background())
 
 	q := dns.Question{Name: "mgmt.example.com.", Qtype: dns.TypeA, Qclass: dns.ClassINET}
 	r.records[q] = &cachedRecord{
@@ -393,7 +393,7 @@ func TestResolver_NoLoopFlagWhenNotRefreshing(t *testing.T) {
 }
 
 func TestResolver_AddDomain_UsesChainWhenRootRegistered(t *testing.T) {
-	r := NewResolver()
+	r := NewResolver(context.Background())
 	chain := newFakeChain()
 	chain.setAnswer("mgmt.example.com.", dns.TypeA, "10.0.0.2")
 	chain.setAnswer("mgmt.example.com.", dns.TypeAAAA, "fd00::2")

client/internal/dns/mgmt/mgmt_test.go

@@ -17,7 +17,7 @@ import (
 )
 
 func TestResolver_NewResolver(t *testing.T) {
-	resolver := NewResolver()
+	resolver := NewResolver(context.Background())
 
 	assert.NotNil(t, resolver)
 	assert.NotNil(t, resolver.records)
@@ -49,7 +49,7 @@ func TestResolveCacheTTL(t *testing.T) {
 
 func TestNewResolver_CacheTTLFromEnv(t *testing.T) {
 	t.Setenv(envMgmtCacheTTL, "7s")
-	r := NewResolver()
+	r := NewResolver(context.Background())
 	assert.Equal(t, 7*time.Second, r.cacheTTL, "NewResolver should evaluate cacheTTL once from env")
 }
 
@@ -169,7 +169,7 @@ func TestResolver_PopulateFromConfig(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
 
-	resolver := NewResolver()
+	resolver := NewResolver(context.Background())
 
 	// Test with IP address - should return error since IP addresses are rejected
 	mgmtURL, _ := url.Parse("https://127.0.0.1")
@@ -184,7 +184,7 @@ func TestResolver_PopulateFromConfig(t *testing.T) {
 }
 
 func TestResolver_ServeDNS(t *testing.T) {
-	resolver := NewResolver()
+	resolver := NewResolver(context.Background())
 	ctx := context.Background()
 
 	// Add a test domain to the cache - use example.org which is reserved for testing
@@ -284,7 +284,7 @@ func TestResolver_ServeDNS(t *testing.T) {
 }
 
 func TestResolver_GetCachedDomains(t *testing.T) {
-	resolver := NewResolver()
+	resolver := NewResolver(context.Background())
 	ctx := context.Background()
 
 	testDomain, err := domain.FromString("example.org")
@@ -304,7 +304,7 @@ func TestResolver_GetCachedDomains(t *testing.T) {
 }
 
 func TestResolver_ManagementDomainProtection(t *testing.T) {
-	resolver := NewResolver()
+	resolver := NewResolver(context.Background())
 	ctx := context.Background()
 
 	mgmtURL, _ := url.Parse("https://example.org")
@@ -352,7 +352,7 @@ func extractDomainFromURL(u *url.URL) (domain.Domain, error) {
 }
 
 func TestResolver_EmptyUpdateDoesNotRemoveDomains(t *testing.T) {
-	resolver := NewResolver()
+	resolver := NewResolver(context.Background())
 	ctx := context.Background()
 
 	// Set up initial domains using resolvable domains
@@ -387,7 +387,7 @@ func TestResolver_EmptyUpdateDoesNotRemoveDomains(t *testing.T) {
 }
 
 func TestResolver_PartialUpdateReplacesOnlyUpdatedTypes(t *testing.T) {
-	resolver := NewResolver()
+	resolver := NewResolver(context.Background())
 	ctx := context.Background()
 
 	// Set up initial complete domains using resolvable domains
@@ -433,7 +433,7 @@ func TestResolver_PartialUpdateReplacesOnlyUpdatedTypes(t *testing.T) {
 }
 
 func TestResolver_PartialUpdateAddsNewTypePreservesExisting(t *testing.T) {
-	resolver := NewResolver()
+	resolver := NewResolver(context.Background())
 	ctx := context.Background()
 
 	// Set up initial complete domains using resolvable domains

client/internal/dns/server.go

@@ -282,7 +282,7 @@ func newDefaultServer(
 	handlerChain := NewHandlerChain()
 	ctx, stop := context.WithCancel(ctx)
 
-	mgmtCacheResolver := mgmt.NewResolver()
+	mgmtCacheResolver := mgmt.NewResolver(ctx)
 	mgmtCacheResolver.SetChainResolver(handlerChain, PriorityUpstream)
 
 	defaultServer := &DefaultServer{