Act as the authority even though were not

letsencrypt needs to talk to the authoritative name server, but
I have all dns traffic redirected to here so we get the SOA using the
same request (probably only works by accident) and then make a request
to the address listed in the SOA

Fix typos in IPv6 addresses

internal/dhcp4/dhcp4.go

@@ -52,6 +52,8 @@ type Client struct {
 	timeNow      func() time.Time
 	generateXID  func() uint32
 
+	timeoutCount int
+
 	// last DHCPACK packet for renewal/release
 	Ack *layers.DHCPv4
 }
@@ -129,7 +131,18 @@ func (c *Client) ObtainOrRenew() bool {
 	ack, err := c.dhcpRequest()
 	if err != nil {
 		if errno, ok := err.(syscall.Errno); ok && errno == syscall.EAGAIN {
-			c.err = fmt.Errorf("DHCP: timeout (server(s) unreachable)")
+			var serverip net.IP
+			for _, opt := range c.Ack.Options {
+				if opt.Type == layers.DHCPOptServerID {
+					serverip = opt.Data
+				}
+			}
+			c.err = fmt.Errorf("DHCP: timeout (server(s) unreachable: %v)", serverip)
+			c.timeoutCount++
+			if c.timeoutCount > 3 {
+				c.timeoutCount = 0
+				c.Ack = nil // start over at DHCPDISCOVER it has failed 3 times
+			}
 			return true // temporary error
 		}
 		if err == errNAK {
@@ -154,6 +167,7 @@ func (c *Client) ObtainOrRenew() bool {
 		}
 	}
 	c.cfg.RenewAfter = c.timeNow().Add(lease.RenewalTime)
+	c.timeoutCount = 0
 	return true
 }
 

internal/dns/dns.go

@@ -92,8 +92,8 @@ func NewServer(addr, domain string) *Server {
 			// https://developers.google.com/speed/public-dns/docs/using#google_public_dns_ip_addresses
 			"1.1.1.1:53",
 			"1.0.0.1:53",
-			"2606:4700:4700::1111:53",
-			"2606:4700:4700::1001:53",
+			"[2606:4700:4700::1111]:53",
+			"[2606:4700:4700::1001]:53",
 			"8.8.8.8:53",
 			"8.8.4.4:53",
 			"[2001:4860:4860::8888]:53",
@@ -536,6 +536,7 @@ func (s *Server) handleRequest(w dns.ResponseWriter, r *dns.Msg) {
 
 	s.promInc("DNS", r)
 
+	if r.RecursionDesired {
 		for idx, u := range s.upstreams() {
 			in, _, err := s.client.Exchange(r, u)
 			if err != nil {
@@ -546,15 +547,15 @@ func (s *Server) handleRequest(w dns.ResponseWriter, r *dns.Msg) {
 			}
 			if len(in.Answer) > 1 {
 				if in.Answer[0].Header().Rrtype == dns.TypeCNAME {
-				for _, rr := range in.Answer {
+					for i, rr := range in.Answer {
 						if rr != nil && rr.Header() != nil && rr.Header().Rrtype == dns.TypeA {
-						if newRR, err := s.resolveSubname("", dns.Question{strings.ToLower(rr.Header().Name), dns.TypeA, dns.ClassINET}); err == nil {
-							in.Answer[len(in.Answer)-1] = newRR
+							newRR, err := s.resolveSubname(string(s.domain), dns.Question{strings.ToLower(rr.Header().Name), dns.TypeA, dns.ClassINET})
+							if err == nil && newRR != nil {
+								in.Answer[i] = newRR
 							}
 						}
 					}
 				}
-
 			}
 			w.WriteMsg(in)
 			if idx > 0 {
@@ -568,6 +569,31 @@ func (s *Server) handleRequest(w dns.ResponseWriter, r *dns.Msg) {
 			}
 			return
 		}
+	} else {
+		for _, u := range s.upstreams() {
+			nr := r.Copy()
+			nr.Question[0].Qtype = dns.TypeSOA
+			nr.RecursionDesired = true
+			soa, _, err := s.client.Exchange(nr, u)
+			fmt.Println(err, soa)
+			fmt.Println()
+			fmt.Println(soa.Ns)
+
+			if len(soa.Ns) > 0 {
+				soa2 := soa.Ns[0].(*dns.SOA)
+				in, _, err := s.client.Exchange(r, strings.TrimRight(soa2.Ns, ".")+":53")
+				fmt.Println(err, in)
+				if err != nil {
+					if s.sometimes.Allow() {
+						log.Printf("resolving %v failed: %v", r.Question, err)
+					}
+					continue // fall back to next-slower upstream
+				}
+				w.WriteMsg(in)
+				return
+			}
+		}
+	}
 	// DNS has no reply for resolving errors
 }