Support dns upstream failover for nameserver groups with same match d…

…omain
netbirdio · Jan 13, 2025 · c728b16 · c728b16
1 parent 3fce848
commit c728b16
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Showing 11 changed files with 322 additions and 174 deletions.
diff --git a/client/internal/dns/handler_chain.go b/client/internal/dns/handler_chain.go
@@ -12,7 +12,7 @@ import (
 const (
 	PriorityDNSRoute    = 100
 	PriorityMatchDomain = 50
-	PriorityDefault     = 0
+	PriorityDefault     = 1
 )
 
 type SubdomainMatcher interface {
@@ -26,7 +26,6 @@ type HandlerEntry struct {
 	Pattern         string
 	OrigPattern     string
 	IsWildcard      bool
-	StopHandler     handlerWithStop
 	MatchSubdomains bool
 }
 
@@ -64,7 +63,7 @@ func (w *ResponseWriterChain) GetOrigPattern() string {
 }
 
 // AddHandler adds a new handler to the chain, replacing any existing handler with the same pattern and priority
-func (c *HandlerChain) AddHandler(pattern string, handler dns.Handler, priority int, stopHandler handlerWithStop) {
+func (c *HandlerChain) AddHandler(pattern string, handler dns.Handler, priority int) {
 	c.mu.Lock()
 	defer c.mu.Unlock()
 
@@ -78,9 +77,6 @@ func (c *HandlerChain) AddHandler(pattern string, handler dns.Handler, priority
 	// First remove any existing handler with same pattern (case-insensitive) and priority
 	for i := len(c.handlers) - 1; i >= 0; i-- {
 		if strings.EqualFold(c.handlers[i].OrigPattern, origPattern) && c.handlers[i].Priority == priority {
-			if c.handlers[i].StopHandler != nil {
-				c.handlers[i].StopHandler.stop()
-			}
 			c.handlers = append(c.handlers[:i], c.handlers[i+1:]...)
 			break
 		}
@@ -101,7 +97,6 @@ func (c *HandlerChain) AddHandler(pattern string, handler dns.Handler, priority
 		Pattern:         pattern,
 		OrigPattern:     origPattern,
 		IsWildcard:      isWildcard,
-		StopHandler:     stopHandler,
 		MatchSubdomains: matchSubdomains,
 	}
 
@@ -129,9 +124,6 @@ func (c *HandlerChain) RemoveHandler(pattern string, priority int) {
 	for i := len(c.handlers) - 1; i >= 0; i-- {
 		entry := c.handlers[i]
 		if strings.EqualFold(entry.OrigPattern, pattern) && entry.Priority == priority {
-			if entry.StopHandler != nil {
-				entry.StopHandler.stop()
-			}
 			c.handlers = append(c.handlers[:i], c.handlers[i+1:]...)
 			return
 		}
@@ -193,13 +185,13 @@ func (c *HandlerChain) ServeDNS(w dns.ResponseWriter, r *dns.Msg) {
 		}
 
 		if !matched {
-			log.Tracef("trying domain match: request: domain=%s pattern: domain=%s wildcard=%v match_subdomain=%v matched=false",
-				qname, entry.OrigPattern, entry.MatchSubdomains, entry.IsWildcard)
+			log.Tracef("trying domain match: request: domain=%s pattern: domain=%s wildcard=%v match_subdomain=%v priority=%d matched=false",
+				qname, entry.OrigPattern, entry.MatchSubdomains, entry.IsWildcard, entry.Priority)
 			continue
 		}
 
-		log.Tracef("handler matched: request: domain=%s pattern: domain=%s wildcard=%v match_subdomain=%v",
-			qname, entry.OrigPattern, entry.IsWildcard, entry.MatchSubdomains)
+		log.Tracef("handler matched: request: domain=%s pattern: domain=%s wildcard=%v match_subdomain=%v priority=%d",
+			qname, entry.OrigPattern, entry.IsWildcard, entry.MatchSubdomains, entry.Priority)
 
 		chainWriter := &ResponseWriterChain{
 			ResponseWriter: w,

diff --git a/client/internal/dns/handler_chain_test.go b/client/internal/dns/handler_chain_test.go
@@ -21,9 +21,9 @@ func TestHandlerChain_ServeDNS_Priorities(t *testing.T) {
 	dnsRouteHandler := &nbdns.MockHandler{}
 
 	// Setup handlers with different priorities
-	chain.AddHandler("example.com.", defaultHandler, nbdns.PriorityDefault, nil)
-	chain.AddHandler("example.com.", matchDomainHandler, nbdns.PriorityMatchDomain, nil)
-	chain.AddHandler("example.com.", dnsRouteHandler, nbdns.PriorityDNSRoute, nil)
+	chain.AddHandler("example.com.", defaultHandler, nbdns.PriorityDefault)
+	chain.AddHandler("example.com.", matchDomainHandler, nbdns.PriorityMatchDomain)
+	chain.AddHandler("example.com.", dnsRouteHandler, nbdns.PriorityDNSRoute)
 
 	// Create test request
 	r := new(dns.Msg)
@@ -138,7 +138,7 @@ func TestHandlerChain_ServeDNS_DomainMatching(t *testing.T) {
 				pattern = "*." + tt.handlerDomain[2:]
 			}
 
-			chain.AddHandler(pattern, handler, nbdns.PriorityDefault, nil)
+			chain.AddHandler(pattern, handler, nbdns.PriorityDefault)
 
 			r := new(dns.Msg)
 			r.SetQuestion(tt.queryDomain, dns.TypeA)
@@ -253,7 +253,7 @@ func TestHandlerChain_ServeDNS_OverlappingDomains(t *testing.T) {
 					handler.On("ServeDNS", mock.Anything, mock.Anything).Maybe()
 				}
 
-				chain.AddHandler(tt.handlers[i].pattern, handler, tt.handlers[i].priority, nil)
+				chain.AddHandler(tt.handlers[i].pattern, handler, tt.handlers[i].priority)
 			}
 
 			// Create and execute request
@@ -280,9 +280,9 @@ func TestHandlerChain_ServeDNS_ChainContinuation(t *testing.T) {
 	handler3 := &nbdns.MockHandler{}
 
 	// Add handlers in priority order
-	chain.AddHandler("example.com.", handler1, nbdns.PriorityDNSRoute, nil)
-	chain.AddHandler("example.com.", handler2, nbdns.PriorityMatchDomain, nil)
-	chain.AddHandler("example.com.", handler3, nbdns.PriorityDefault, nil)
+	chain.AddHandler("example.com.", handler1, nbdns.PriorityDNSRoute)
+	chain.AddHandler("example.com.", handler2, nbdns.PriorityMatchDomain)
+	chain.AddHandler("example.com.", handler3, nbdns.PriorityDefault)
 
 	// Create test request
 	r := new(dns.Msg)
@@ -416,7 +416,7 @@ func TestHandlerChain_PriorityDeregistration(t *testing.T) {
 				if op.action == "add" {
 					handler := &nbdns.MockHandler{}
 					handlers[op.priority] = handler
-					chain.AddHandler(op.pattern, handler, op.priority, nil)
+					chain.AddHandler(op.pattern, handler, op.priority)
 				} else {
 					chain.RemoveHandler(op.pattern, op.priority)
 				}
@@ -471,9 +471,9 @@ func TestHandlerChain_MultiPriorityHandling(t *testing.T) {
 	r.SetQuestion(testQuery, dns.TypeA)
 
 	// Add handlers in mixed order
-	chain.AddHandler(testDomain, defaultHandler, nbdns.PriorityDefault, nil)
-	chain.AddHandler(testDomain, routeHandler, nbdns.PriorityDNSRoute, nil)
-	chain.AddHandler(testDomain, matchHandler, nbdns.PriorityMatchDomain, nil)
+	chain.AddHandler(testDomain, defaultHandler, nbdns.PriorityDefault)
+	chain.AddHandler(testDomain, routeHandler, nbdns.PriorityDNSRoute)
+	chain.AddHandler(testDomain, matchHandler, nbdns.PriorityMatchDomain)
 
 	// Test 1: Initial state with all three handlers
 	w := &nbdns.ResponseWriterChain{ResponseWriter: &mockResponseWriter{}}
@@ -653,7 +653,7 @@ func TestHandlerChain_CaseSensitivity(t *testing.T) {
 					handler = mockHandler
 				}
 
-				chain.AddHandler(pattern, handler, h.priority, nil)
+				chain.AddHandler(pattern, handler, h.priority)
 			}
 
 			// Execute request

diff --git a/client/internal/dns/local.go b/client/internal/dns/local.go
@@ -29,10 +29,15 @@ func (d *localResolver) String() string {
 	return fmt.Sprintf("local resolver [%d records]", len(d.registeredMap))
 }
 
+// ID returns the unique handler ID
+func (d *localResolver) id() handlerID {
+	return "local-resolver"
+}
+
 // ServeDNS handles a DNS request
 func (d *localResolver) ServeDNS(w dns.ResponseWriter, r *dns.Msg) {
 	if len(r.Question) > 0 {
-		log.Tracef("received question: domain=%s type=%v class=%v", r.Question[0].Name, r.Question[0].Qtype, r.Question[0].Qclass)
+		log.Tracef("received local question: domain=%s type=%v class=%v", r.Question[0].Name, r.Question[0].Qtype, r.Question[0].Qclass)
 	}
 
 	replyMessage := &dns.Msg{}