all: fallback to use direct IPs for ControlD assets

cmd/cli/commands.go

@@ -1278,8 +1278,9 @@ func initUpgradeCmd() *cobra.Command {
 			dlUrl := upgradeUrl(baseUrl)
 			mainLog.Load().Debug().Msgf("Downloading binary: %s", dlUrl)
 
-			resp, err := getWithRetry(dlUrl)
+			resp, err := getWithRetry(dlUrl, downloadServerIp)
 			if err != nil {
+
 				mainLog.Load().Fatal().Err(err).Msg("failed to download binary")
 			}
 			defer resp.Body.Close()

cmd/cli/dns_proxy.go

@@ -519,13 +519,8 @@ func (p *prog) proxy(ctx context.Context, req *proxyRequest) *proxyResponse {
 			ctrld.Log(ctx, mainLog.Load().Error().Err(err), "failed to create resolver")
 			return nil, err
 		}
-		resolveCtx, cancel := context.WithCancel(ctx)
+		resolveCtx, cancel := upstreamConfig.Context(ctx)
 		defer cancel()
-		if upstreamConfig.Timeout > 0 {
-			timeoutCtx, cancel := context.WithTimeout(resolveCtx, time.Millisecond*time.Duration(upstreamConfig.Timeout))
-			defer cancel()
-			resolveCtx = timeoutCtx
-		}
 		return dnsResolver.Resolve(resolveCtx, msg)
 	}
 	resolve := func(upstream string, upstreamConfig *ctrld.UpstreamConfig, msg *dns.Msg) *dns.Msg {

cmd/cli/library.go

@@ -28,6 +28,7 @@ type AppConfig struct {
 const (
 	defaultHTTPTimeout = 30 * time.Second
 	defaultMaxRetries  = 3
+	downloadServerIp   = "23.171.240.151"
 )
 
 // httpClientWithFallback returns an HTTP client configured with timeout and IPv4 fallback
@@ -46,10 +47,15 @@ func httpClientWithFallback(timeout time.Duration) *http.Client {
 }
 
 // doWithRetry performs an HTTP request with retries
-func doWithRetry(req *http.Request, maxRetries int) (*http.Response, error) {
+func doWithRetry(req *http.Request, maxRetries int, ip string) (*http.Response, error) {
 	var lastErr error
 	client := httpClientWithFallback(defaultHTTPTimeout)
-
+	var ipReq *http.Request
+	if ip != "" {
+		ipReq = req.Clone(req.Context())
+		ipReq.Host = ip
+		ipReq.URL.Host = ip
+	}
 	for attempt := 0; attempt < maxRetries; attempt++ {
 		if attempt > 0 {
 			time.Sleep(time.Second * time.Duration(attempt+1)) // Exponential backoff
@@ -59,6 +65,15 @@ func doWithRetry(req *http.Request, maxRetries int) (*http.Response, error) {
 		if err == nil {
 			return resp, nil
 		}
+		if ipReq != nil {
+			mainLog.Load().Warn().Err(err).Msgf("dial to %q failed", req.Host)
+			mainLog.Load().Warn().Msgf("fallback to direct IP to download prod version: %q", ip)
+			resp, err = client.Do(ipReq)
+			if err == nil {
+				return resp, nil
+			}
+		}
+
 		lastErr = err
 		mainLog.Load().Debug().Err(err).
 			Str("method", req.Method).
@@ -69,10 +84,10 @@ func doWithRetry(req *http.Request, maxRetries int) (*http.Response, error) {
 }
 
 // Helper for making GET requests with retries
-func getWithRetry(url string) (*http.Response, error) {
+func getWithRetry(url string, ip string) (*http.Response, error) {
 	req, err := http.NewRequest(http.MethodGet, url, nil)
 	if err != nil {
 		return nil, err
 	}
-	return doWithRetry(req, defaultMaxRetries)
+	return doWithRetry(req, defaultMaxRetries, ip)
 }

config.go

@@ -53,10 +53,27 @@ const (
 	FreeDnsDomain = "freedns.controld.com"
 	// FreeDNSBoostrapIP is the IP address of freedns.controld.com.
 	FreeDNSBoostrapIP = "76.76.2.11"
+	// FreeDNSBoostrapIPv6 is the IPv6 address of freedns.controld.com.
+	FreeDNSBoostrapIPv6 = "2606:1a40::11"
 	// PremiumDnsDomain is the domain name of premium ControlD service.
 	PremiumDnsDomain = "dns.controld.com"
 	// PremiumDNSBoostrapIP is the IP address of dns.controld.com.
 	PremiumDNSBoostrapIP = "76.76.2.22"
+	// PremiumDNSBoostrapIPv6 is the IPv6 address of dns.controld.com.
+	PremiumDNSBoostrapIPv6 = "2606:1a40::22"
+
+	// freeDnsDomainDev is the domain name of free ControlD service on dev env.
+	freeDnsDomainDev = "freedns.controld.dev"
+	// freeDNSBoostrapIP is the IP address of freedns.controld.dev.
+	freeDNSBoostrapIP = "176.125.239.11"
+	// freeDNSBoostrapIPv6 is the IPv6 address of freedns.controld.com.
+	freeDNSBoostrapIPv6 = "2606:1a40:f000::11"
+	// premiumDnsDomainDev is the domain name of premium ControlD service on dev env.
+	premiumDnsDomainDev = "dns.controld.dev"
+	// premiumDNSBoostrapIP is the IP address of dns.controld.dev.
+	premiumDNSBoostrapIP = "176.125.239.22"
+	// premiumDNSBoostrapIPv6 is the IPv6 address of dns.controld.dev.
+	premiumDNSBoostrapIPv6 = "2606:1a40:f000::22"
 
 	controlDComDomain = "controld.com"
 	controlDNetDomain = "controld.net"
@@ -261,6 +278,7 @@ type UpstreamConfig struct {
 	http3RoundTripper6 http.RoundTripper
 	certPool           *x509.CertPool
 	u                  *url.URL
+	fallbackOnce       sync.Once
 	uid                string
 }
 
@@ -426,6 +444,10 @@ func (uc *UpstreamConfig) SetupBootstrapIP() {
 				}
 			}
 			uc.bootstrapIPs = uc.bootstrapIPs[:n]
+			if len(uc.bootstrapIPs) == 0 {
+				uc.bootstrapIPs = bootstrapIPsFromControlDDomain(uc.Domain)
+				ProxyLogger.Load().Warn().Msgf("no bootstrap IPs found for %q, fallback to direct IPs", uc.Domain)
+			}
 		}
 		if len(uc.bootstrapIPs) > 0 {
 			break
@@ -538,7 +560,10 @@ func (uc *UpstreamConfig) newDOHTransport(addrs []string) *http.Transport {
 
 // Ping warms up the connection to DoH/DoH3 upstream.
 func (uc *UpstreamConfig) Ping() {
-	_ = uc.ping()
+	if err := uc.ping(); err != nil {
+		ProxyLogger.Load().Debug().Err(err).Msgf("upstream ping failed: %s", uc.Endpoint)
+		_ = uc.FallbackToDirectIP()
+	}
 }
 
 // ErrorPing is like Ping, but return an error if any.
@@ -575,7 +600,6 @@ func (uc *UpstreamConfig) ping() error {
 	for _, typ := range []uint16{dns.TypeA, dns.TypeAAAA} {
 		switch uc.Type {
 		case ResolverTypeDOH:
-
 			if err := ping(uc.dohTransport(typ)); err != nil {
 				return err
 			}
@@ -743,6 +767,41 @@ func (uc *UpstreamConfig) initDnsStamps() error {
 	return nil
 }
 
+// Context returns a new context with timeout set from upstream config.
+func (uc *UpstreamConfig) Context(ctx context.Context) (context.Context, context.CancelFunc) {
+	if uc.Timeout > 0 {
+		return context.WithTimeout(ctx, time.Millisecond*time.Duration(uc.Timeout))
+	}
+	return context.WithCancel(ctx)
+}
+
+// FallbackToDirectIP changes ControlD upstream endpoint to use direct IP instead of domain.
+func (uc *UpstreamConfig) FallbackToDirectIP() bool {
+	if !uc.IsControlD() {
+		return false
+	}
+	if uc.u == nil || uc.Domain == "" {
+		return false
+	}
+
+	done := false
+	uc.fallbackOnce.Do(func() {
+		var ip string
+		switch {
+		case dns.IsSubDomain(PremiumDnsDomain, uc.Domain):
+			ip = PremiumDNSBoostrapIP
+		case dns.IsSubDomain(FreeDnsDomain, uc.Domain):
+			ip = FreeDNSBoostrapIP
+		default:
+			return
+		}
+		ProxyLogger.Load().Warn().Msgf("using direct IP for %q: %s", uc.Endpoint, ip)
+		uc.u.Host = ip
+		done = true
+	})
+	return done
+}
+
 // Init initialized necessary values for an ListenerConfig.
 func (lc *ListenerConfig) Init() {
 	if lc.Policy != nil {
@@ -889,3 +948,18 @@ func (uc *UpstreamConfig) String() string {
 	return fmt.Sprintf("{name: %q, type: %q, endpoint: %q, bootstrap_ip: %q, domain: %q, ip_stack: %q}",
 		uc.Name, uc.Type, uc.Endpoint, uc.BootstrapIP, uc.Domain, uc.IPStack)
 }
+
+// bootstrapIPsFromControlDDomain returns bootstrap IPs for ControlD domain.
+func bootstrapIPsFromControlDDomain(domain string) []string {
+	switch domain {
+	case PremiumDnsDomain:
+		return []string{PremiumDNSBoostrapIP, PremiumDNSBoostrapIPv6}
+	case FreeDnsDomain:
+		return []string{FreeDNSBoostrapIP, FreeDNSBoostrapIPv6}
+	case premiumDnsDomainDev:
+		return []string{premiumDNSBoostrapIP, premiumDNSBoostrapIPv6}
+	case freeDnsDomainDev:
+		return []string{freeDNSBoostrapIP, freeDNSBoostrapIPv6}
+	}
+	return nil
+}

doh.go

@@ -113,6 +113,12 @@ func (r *dohResolver) Resolve(ctx context.Context, msg *dns.Msg) (*dns.Msg, erro
 		c.Transport = transport
 	}
 	resp, err := c.Do(req)
+	if err != nil && r.uc.FallbackToDirectIP() {
+		retryCtx, cancel := r.uc.Context(context.WithoutCancel(ctx))
+		defer cancel()
+		Log(ctx, ProxyLogger.Load().Warn().Err(err), "retrying request after fallback to direct ip")
+		resp, err = c.Do(req.Clone(retryCtx))
+	}
 	if err != nil {
 		if r.isDoH3 {
 			if closer, ok := c.Transport.(io.Closer); ok {

internal/controld/config.go

@@ -24,7 +24,10 @@ import (
 
 const (
 	apiDomainCom       = "api.controld.com"
+	apiDomainComIPv4   = "147.185.34.1"
+	apiDomainComIPv6   = "2606:1a40:3::1"
 	apiDomainDev       = "api.controld.dev"
+	apiDomainDevIPv4   = "23.171.240.84"
 	apiURLCom          = "https://api.controld.com"
 	apiURLDev          = "https://api.controld.dev"
 	resolverDataURLCom = apiURLCom + "/utility"
@@ -136,11 +139,11 @@ func postUtilityAPI(version string, cdDev, lastUpdatedFailed bool, body io.Reade
 	req.URL.RawQuery = q.Encode()
 	req.Header.Add("Content-Type", "application/json")
 	transport := apiTransport(cdDev)
-	client := http.Client{
+	client := &http.Client{
 		Timeout:   defaultTimeout,
 		Transport: transport,
 	}
-	resp, err := client.Do(req)
+	resp, err := doWithFallback(client, req, apiServerIP(cdDev))
 	if err != nil {
 		return nil, fmt.Errorf("postUtilityAPI client.Do: %w", err)
 	}
@@ -177,11 +180,11 @@ func SendLogs(lr *LogsRequest, cdDev bool) error {
 	req.URL.RawQuery = q.Encode()
 	req.Header.Add("Content-Type", "application/x-www-form-urlencoded")
 	transport := apiTransport(cdDev)
-	client := http.Client{
+	client := &http.Client{
 		Timeout:   sendLogTimeout,
 		Transport: transport,
 	}
-	resp, err := client.Do(req)
+	resp, err := doWithFallback(client, req, apiServerIP(cdDev))
 	if err != nil {
 		return fmt.Errorf("SendLogs client.Do: %w", err)
 	}
@@ -213,20 +216,20 @@ func apiTransport(cdDev bool) *http.Transport {
 	transport := http.DefaultTransport.(*http.Transport).Clone()
 	transport.DialContext = func(ctx context.Context, network, addr string) (net.Conn, error) {
 		apiDomain := apiDomainCom
+		apiIpsV4 := []string{apiDomainComIPv4}
+		apiIpsV6 := []string{apiDomainComIPv6}
+		apiIPs := []string{apiDomainComIPv4, apiDomainComIPv6}
 		if cdDev {
 			apiDomain = apiDomainDev
-		}
-
-		// First try IPv4
-		dialer := &net.Dialer{
-			Timeout:   10 * time.Second,
-			KeepAlive: 30 * time.Second,
+			apiIpsV4 = []string{apiDomainDevIPv4}
+			apiIpsV6 = []string{}
+			apiIPs = []string{apiDomainDevIPv4}
 		}
 
 		ips := ctrld.LookupIP(apiDomain)
 		if len(ips) == 0 {
-			ctrld.ProxyLogger.Load().Warn().Msgf("No IPs found for %s, falling back to direct connection to %s", apiDomain, addr)
-			return dialer.DialContext(ctx, network, addr)
+			ctrld.ProxyLogger.Load().Warn().Msgf("No IPs found for %s, use direct IPs: %v", apiDomain, apiIPs)
+			ips = apiIPs
 		}
 
 		// Separate IPv4 and IPv6 addresses
@@ -239,35 +242,62 @@ func apiTransport(cdDev bool) *http.Transport {
 			}
 		}
 
+		dial := func(ctx context.Context, network string, addrs []string) (net.Conn, error) {
+			d := &ctrldnet.ParallelDialer{}
+			return d.DialContext(ctx, network, addrs, ctrld.ProxyLogger.Load())
+		}
 		_, port, _ := net.SplitHostPort(addr)
 
 		// Try IPv4 first
 		if len(ipv4s) > 0 {
-			addrs := make([]string, len(ipv4s))
-			for i, ip := range ipv4s {
-				addrs[i] = net.JoinHostPort(ip, port)
-			}
-			d := &ctrldnet.ParallelDialer{}
-			if conn, err := d.DialContext(ctx, "tcp4", addrs, ctrld.ProxyLogger.Load()); err == nil {
+			if conn, err := dial(ctx, "tcp4", addrsFromPort(ipv4s, port)); err == nil {
 				return conn, nil
 			}
 		}
-
-		// Fall back to IPv6 if available
-		if len(ipv6s) > 0 {
-			addrs := make([]string, len(ipv6s))
-			for i, ip := range ipv6s {
-				addrs[i] = net.JoinHostPort(ip, port)
-			}
-			d := &ctrldnet.ParallelDialer{}
-			return d.DialContext(ctx, "tcp6", addrs, ctrld.ProxyLogger.Load())
+		// Fallback to direct IPv4
+		if conn, err := dial(ctx, "tcp4", addrsFromPort(apiIpsV4, port)); err == nil {
+			return conn, nil
 		}
 
-		// Final fallback to direct connection
-		return dialer.DialContext(ctx, network, addr)
+		// Fallback to IPv6 if available
+		if len(ipv6s) > 0 {
+			if conn, err := dial(ctx, "tcp6", addrsFromPort(ipv6s, port)); err == nil {
+				return conn, nil
+			}
+		}
+		// Fallback to direct IPv6
+		return dial(ctx, "tcp6", addrsFromPort(apiIpsV6, port))
 	}
 	if router.Name() == ddwrt.Name || runtime.GOOS == "android" {
 		transport.TLSClientConfig = &tls.Config{RootCAs: certs.CACertPool()}
 	}
 	return transport
 }
+
+func addrsFromPort(ips []string, port string) []string {
+	addrs := make([]string, len(ips))
+	for i, ip := range ips {
+		addrs[i] = net.JoinHostPort(ip, port)
+	}
+	return addrs
+}
+
+func doWithFallback(client *http.Client, req *http.Request, apiIp string) (*http.Response, error) {
+	resp, err := client.Do(req)
+	if err != nil {
+		ctrld.ProxyLogger.Load().Warn().Err(err).Msgf("failed to send request, fallback to direct IP: %s", apiIp)
+		ipReq := req.Clone(req.Context())
+		ipReq.Host = apiIp
+		ipReq.URL.Host = apiIp
+		resp, err = client.Do(ipReq)
+	}
+	return resp, err
+}
+
+// apiServerIP returns the direct IP to connect to API server.
+func apiServerIP(cdDev bool) string {
+	if cdDev {
+		return apiDomainDevIPv4
+	}
+	return apiDomainComIPv4
+}