More idomatic

ex/check-soa/check-soa.go

@@ -20,17 +20,11 @@ var (
 )
 
 func localQuery(qname string, qtype uint16) (r *dns.Msg, err error) {
-	localm.Question[0] = dns.Question{qname, qtype, dns.ClassINET}
+	localm.SetQuestion(qname, qtype)
-	for serverIndex := range conf.Servers {
+	for i := range conf.Servers {
-		server := conf.Servers[serverIndex]
+		server := conf.Servers[i]
 		r, err := localc.Exchange(localm, server+":"+conf.Port)
-		if r == nil {
+		if r == nil || r.Rcode == dns.RcodeNameError || r.Rcode == dns.RcodeSuccess {
-			return r, err
-		}
-		if r.Rcode == dns.RcodeNameError {
-			return r, err
-		}
-		if r.Rcode == dns.RcodeSuccess {
 			return r, err
 		}
 	}
@@ -38,17 +32,11 @@ func localQuery(qname string, qtype uint16) (r *dns.Msg, err error) {
 }
 
 func main() {
-	var (
+	var err error
-		err error
-	)
 	if len(os.Args) != 2 {
 		fmt.Printf("%s ZONE\n", os.Args[0])
 		os.Exit(1)
 	}
-	zone := os.Args[1]
-	if zone[len(zone)-1] != '.' {
-		zone += "."
-	}
 	conf, err = dns.ClientConfigFromFile("/etc/resolv.conf")
 	if conf == nil {
 		fmt.Printf("Cannot initialize the local resolver: %s\n", err)
@@ -59,13 +47,13 @@ func main() {
 	localm.Question = make([]dns.Question, 1)
 	localc = new(dns.Client)
 	localc.ReadTimeout = TIMEOUT * 1e9
-	r, err := localQuery(zone, dns.TypeNS)
+	r, err := localQuery(dns.Fqdn(os.Args[1]), dns.TypeNS)
 	if r == nil {
-		fmt.Printf("Cannot retrieve the list of name servers for %s: %s\n", zone, err)
+		fmt.Printf("Cannot retrieve the list of name servers for %s: %s\n", dns.Fqdn(os.Args[1]), err)
 		os.Exit(1)
 	}
 	if r.Rcode == dns.RcodeNameError {
-		fmt.Printf("No such domain %s\n", zone)
+		fmt.Printf("No such domain %s\n", dns.Fqdn(os.Args[1]))
 		os.Exit(1)
 	}
 	m := new(dns.Msg)
@@ -75,8 +63,7 @@ func main() {
 	c.ReadTimeout = TIMEOUT * 1e9
 	success := true
 	numNS := 0
-	for i := range r.Answer {
+	for _, ans := range r.Answer {
-		ans := r.Answer[i]
 		switch ans.(type) {
 		case *dns.RR_NS:
 			nameserver := ans.(*dns.RR_NS).Ns
@@ -92,8 +79,7 @@ func main() {
 				fmt.Printf("Error getting the IPv4 address of %s: %s\n", nameserver, dns.Rcode_str[ra.Rcode])
 				os.Exit(1)
 			}
-			for j := range ra.Answer {
+			for _, ansa := range ra.Answer {
-				ansa := ra.Answer[j]
 				switch ansa.(type) {
 				case *dns.RR_A:
 					ips = append(ips, ansa.(*dns.RR_A).A.String())
@@ -108,8 +94,7 @@ func main() {
 				fmt.Printf("Error getting the IPv6 address of %s: %s\n", nameserver, dns.Rcode_str[raaaa.Rcode])
 				os.Exit(1)
 			}
-			for j := range raaaa.Answer {
+			for _, ansaaaa := range raaaa.Answer {
-				ansaaaa := raaaa.Answer[j]
 				switch ansaaaa.(type) {
 				case *dns.RR_AAAA:
 					ips = append(ips, ansaaaa.(*dns.RR_AAAA).AAAA.String())
@@ -119,38 +104,38 @@ func main() {
 				success = false
 				fmt.Printf("No IP address for this server")
 			}
-			for j := range ips {
+			for _, ip := range ips {
-				m.Question[0] = dns.Question{zone, dns.TypeSOA, dns.ClassINET}
+				m.Question[0] = dns.Question{dns.Fqdn(os.Args[1]), dns.TypeSOA, dns.ClassINET}
 				nsAddressPort := ""
-				if strings.ContainsAny(":", ips[j]) {
+				if strings.ContainsAny(":", ip) {
 					/* IPv6 address */
-					nsAddressPort = "[" + ips[j] + "]:53"
+					nsAddressPort = "[" + ip + "]:53"
 				} else {
-					nsAddressPort = ips[j] + ":53"
+					nsAddressPort = ip + ":53"
 				}
 				soa, err := c.Exchange(m, nsAddressPort)
-				/* TODO: retry if timeout? Otherwise, one lost UDP packet and it is the end ... */
+				// TODO: retry if timeout? Otherwise, one lost UDP packet and it is the end
 				if soa == nil {
 					success = false
-					fmt.Printf("%s (%s) ", ips[j], err)
+					fmt.Printf("%s (%s) ", ip, err)
 				} else {
 					if soa.Rcode != dns.RcodeSuccess {
 						success = false
-						fmt.Printf("%s (%s) ", ips[j], dns.Rcode_str[soa.Rcode])
+						fmt.Printf("%s (%s) ", ips, dns.Rcode_str[soa.Rcode])
 					} else {
 						if len(soa.Answer) == 0 { /* May happen if the server is a recursor, not authoritative, since we query with RD=0 */
 							success = false
-							fmt.Printf("%s (0 answer) ", ips[j])
+							fmt.Printf("%s (0 answer) ", ip)
 						} else {
 							rsoa := soa.Answer[0]
 							switch rsoa.(type) {
 							case *dns.RR_SOA:
 								if soa.MsgHdr.Authoritative {
 									/* TODO: test if all name servers have the same serial ? */
-									fmt.Printf("%s (%d) ", ips[j], rsoa.(*dns.RR_SOA).Serial)
+									fmt.Printf("%s (%d) ", ips, rsoa.(*dns.RR_SOA).Serial)
 								} else {
 									success = false
-									fmt.Printf("%s (not authoritative) ", ips[j])
+									fmt.Printf("%s (not authoritative) ", ips)
 								}
 							}
 						}
@@ -161,12 +146,11 @@ func main() {
 		}
 	}
 	if numNS == 0 {
-		fmt.Printf("No NS records for \"%s\". It is probably a CNAME to a domain but not a zone\n", zone)
+		fmt.Printf("No NS records for \"%s\". It is probably a CNAME to a domain but not a zone\n", dns.Fqdn(os.Args[1]))
 		os.Exit(1)
 	}
 	if success {
 		os.Exit(0)
-	} else {
-		os.Exit(1)
 	}
+	os.Exit(1)
 }