set new dialer on every request

debugging debugging debugging debugging use default route interface IP for OS resolver queries remove retries fix resolv.conf clobbering on MacOS, set custom local addr for os resolver queries remove the client info discovery logic on network change, this was overkill just for the IP, and was causing service failure after switching networks many times rapidly handle ipv6 local addresses guard ciTable from nil pointer debugging failure count
2026-07-04 01:07:49 +02:00 · 2025-02-05 01:41:16 -05:00
parent 60686f55ff
commit cf6d16b439
7 changed files with 317 additions and 35 deletions
@@ -99,6 +99,7 @@ func (p *prog) serveDNS(mainCtx context.Context, listenerNum string) error {
 	}

 	handler := dns.HandlerFunc(func(w dns.ResponseWriter, m *dns.Msg) {
+		mainLog.Load().Debug().Msgf("serveDNS handler called")
 		p.sema.acquire()
 		defer p.sema.release()
 		if len(m.Question) == 0 {
@@ -1238,7 +1239,10 @@ func (p *prog) reinitializeOSResolver(networkChange bool) {
 	defer p.resetCtxMu.Unlock()

 	p.leakingQueryReset.Store(true)
-	defer p.leakingQueryReset.Store(false)
+	defer func() {
+		time.Sleep(time.Second)
+		p.leakingQueryReset.Store(false)
+	}()

 	mainLog.Load().Debug().Msg("attempting to reset DNS")
 	p.resetDNS()
@@ -1260,7 +1264,6 @@ func (p *prog) reinitializeOSResolver(networkChange bool) {
 		if err := FlushDNSCache(); err != nil {
 			mainLog.Load().Warn().Err(err).Msg("failed to flush DNS cache")
 		}
-
 		if runtime.GOOS == "darwin" {
 			// delay putting back the ctrld listener to allow for captive portal to trigger
 			time.Sleep(5 * time.Second)
@@ -1316,21 +1319,9 @@ func (p *prog) monitorNetworkChanges(ctx context.Context) error {
 		oldIfs := parseInterfaceState(delta.Old)
 		newIfs := parseInterfaceState(delta.New)

-		// Client info discover only run on non-mobile platforms.
-		if !isMobile() {
-			// If this is major change, re-init client info table if its self IP changes.
-			if delta.Monitor.IsMajorChangeFrom(delta.Old, delta.New) {
-				selfIP := defaultRouteIP()
-				if currentSelfIP := p.ciTable.SelfIP(); currentSelfIP != selfIP && selfIP != "" {
-					p.stopClientInfoDiscover()
-					p.setupClientInfoDiscover(selfIP)
-					p.runClientInfoDiscover(ctx)
-				}
-			}
-		}
-
 		// Check for changes in valid interfaces
 		changed := false
+		var changedIface, changedIfaceState string
 		activeInterfaceExists := false

 		for ifaceName := range validIfaces {
@@ -1343,7 +1334,14 @@ func (p *prog) monitorNetworkChanges(ctx context.Context) error {

 			// Compare states directly
 			if oldExists != newExists || oldState != newState {
-				changed = true
+
+				// If the interface is up, we need to reinitialize the OS resolver
+				if newState != "" && !strings.Contains(newState, "down") {
+					changed = true
+					changedIface = ifaceName
+					changedIfaceState = newState
+				}
+
 				mainLog.Load().Warn().
 					Str("interface", ifaceName).
 					Str("old_state", oldState).
@@ -1364,11 +1362,33 @@ func (p *prog) monitorNetworkChanges(ctx context.Context) error {
 			return
 		}

-		if activeInterfaceExists {
-			p.reinitializeOSResolver(true)
-		} else {
+		if !activeInterfaceExists {
 			mainLog.Load().Warn().Msg("No active interfaces found, skipping reinitialization")
+			return
 		}
+
+		// Use the defaultRouteIP() result or fallback to the changed interface's IP from the delta.
+		selfIP := defaultRouteIP()
+		if selfIP == "" && changedIface != "" {
+			selfIP = extractIPv4FromState(changedIfaceState)
+			mainLog.Load().Info().Msgf("defaultRouteIP returned empty, using changed iface '%s' IP: %s", changedIface, selfIP)
+		}
+
+		// Extract IPv6 from the changed interface state.
+		ipv6 := extractIPv6FromState(changedIfaceState)
+
+		if ip := net.ParseIP(selfIP); ip != nil {
+			ctrld.SetDefaultLocalIPv4(ip)
+			// if we have a new IP, set the client info to the new IP
+			if !isMobile() && p.ciTable != nil {
+				p.ciTable.SetSelfIP(selfIP)
+			}
+		}
+		if ip := net.ParseIP(ipv6); ip != nil {
+			ctrld.SetDefaultLocalIPv6(ip)
+		}
+		mainLog.Load().Debug().Msgf("Set default local IPv4: %s, IPv6: %s", selfIP, ipv6)
+		p.reinitializeOSResolver(true)
 	})

 	mon.Start()
@@ -1423,3 +1443,33 @@ func parseInterfaceState(state *netmon.State) map[string]string {

 	return result
 }
+
+// extractIPv4FromState extracts an IPv4 address from an interface state string.
+// For example, given "[172.16.226.239/22 llu6]", it returns "172.16.226.239".
+// If no valid IP can be found, it returns an empty string.
+func extractIPv4FromState(state string) string {
+	trimmed := strings.Trim(state, "[]")
+	parts := strings.Fields(trimmed)
+	for _, part := range parts {
+		ipPart := strings.Split(part, "/")[0]
+		if ip := net.ParseIP(ipPart); ip != nil && ip.To4() != nil {
+			return ipPart
+		}
+	}
+	return ""
+}
+
+// extractIPv6FromState extracts an IPv6 address from an interface state string.
+// For example, given "[172.16.226.239/22 llu6]", it returns "172.16.226.239".
+// If no valid IP can be found, it returns an empty string.
+func extractIPv6FromState(state string) string {
+	trimmed := strings.Trim(state, "[]")
+	parts := strings.Fields(trimmed)
+	for _, part := range parts {
+		ipPart := strings.Split(part, "/")[0]
+		if ip := net.ParseIP(ipPart); ip != nil && ip.To4() == nil {
+			return ipPart
+		}
+	}
+	return ""
+}