More idomatic
This commit is contained in:
Miek Gieben
parent
708b4575ad
commit
48c41f56c9
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@ -20,17 +20,11 @@ var (
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)
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func localQuery(qname string, qtype uint16) (r *dns.Msg, err error) {
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localm.Question[0] = dns.Question{qname, qtype, dns.ClassINET}
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for serverIndex := range conf.Servers {
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server := conf.Servers[serverIndex]
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localm.SetQuestion(qname, qtype)
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for i := range conf.Servers {
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server := conf.Servers[i]
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r, err := localc.Exchange(localm, server+":"+conf.Port)
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if r == nil {
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return r, err
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}
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if r.Rcode == dns.RcodeNameError {
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return r, err
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}
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if r.Rcode == dns.RcodeSuccess {
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if r == nil || r.Rcode == dns.RcodeNameError || r.Rcode == dns.RcodeSuccess {
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return r, err
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}
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}
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@ -38,17 +32,11 @@ func localQuery(qname string, qtype uint16) (r *dns.Msg, err error) {
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}
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func main() {
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var (
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err error
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)
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var err error
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if len(os.Args) != 2 {
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fmt.Printf("%s ZONE\n", os.Args[0])
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os.Exit(1)
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}
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zone := os.Args[1]
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if zone[len(zone)-1] != '.' {
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zone += "."
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}
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conf, err = dns.ClientConfigFromFile("/etc/resolv.conf")
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if conf == nil {
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fmt.Printf("Cannot initialize the local resolver: %s\n", err)
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@ -59,13 +47,13 @@ func main() {
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localm.Question = make([]dns.Question, 1)
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localc = new(dns.Client)
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localc.ReadTimeout = TIMEOUT * 1e9
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r, err := localQuery(zone, dns.TypeNS)
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r, err := localQuery(dns.Fqdn(os.Args[1]), dns.TypeNS)
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if r == nil {
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fmt.Printf("Cannot retrieve the list of name servers for %s: %s\n", zone, err)
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fmt.Printf("Cannot retrieve the list of name servers for %s: %s\n", dns.Fqdn(os.Args[1]), err)
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os.Exit(1)
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}
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if r.Rcode == dns.RcodeNameError {
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fmt.Printf("No such domain %s\n", zone)
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fmt.Printf("No such domain %s\n", dns.Fqdn(os.Args[1]))
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os.Exit(1)
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}
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m := new(dns.Msg)
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@ -75,8 +63,7 @@ func main() {
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c.ReadTimeout = TIMEOUT * 1e9
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success := true
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numNS := 0
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for i := range r.Answer {
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ans := r.Answer[i]
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for _, ans := range r.Answer {
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switch ans.(type) {
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case *dns.RR_NS:
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nameserver := ans.(*dns.RR_NS).Ns
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@ -92,8 +79,7 @@ func main() {
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fmt.Printf("Error getting the IPv4 address of %s: %s\n", nameserver, dns.Rcode_str[ra.Rcode])
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os.Exit(1)
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}
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for j := range ra.Answer {
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ansa := ra.Answer[j]
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for _, ansa := range ra.Answer {
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switch ansa.(type) {
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case *dns.RR_A:
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ips = append(ips, ansa.(*dns.RR_A).A.String())
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@ -108,8 +94,7 @@ func main() {
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fmt.Printf("Error getting the IPv6 address of %s: %s\n", nameserver, dns.Rcode_str[raaaa.Rcode])
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os.Exit(1)
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}
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for j := range raaaa.Answer {
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ansaaaa := raaaa.Answer[j]
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for _, ansaaaa := range raaaa.Answer {
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switch ansaaaa.(type) {
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case *dns.RR_AAAA:
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ips = append(ips, ansaaaa.(*dns.RR_AAAA).AAAA.String())
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@ -119,38 +104,38 @@ func main() {
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success = false
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fmt.Printf("No IP address for this server")
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}
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for j := range ips {
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m.Question[0] = dns.Question{zone, dns.TypeSOA, dns.ClassINET}
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for _, ip := range ips {
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m.Question[0] = dns.Question{dns.Fqdn(os.Args[1]), dns.TypeSOA, dns.ClassINET}
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nsAddressPort := ""
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if strings.ContainsAny(":", ips[j]) {
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if strings.ContainsAny(":", ip) {
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/* IPv6 address */
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nsAddressPort = "[" + ips[j] + "]:53"
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nsAddressPort = "[" + ip + "]:53"
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} else {
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nsAddressPort = ips[j] + ":53"
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nsAddressPort = ip + ":53"
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}
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soa, err := c.Exchange(m, nsAddressPort)
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/* TODO: retry if timeout? Otherwise, one lost UDP packet and it is the end ... */
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// TODO: retry if timeout? Otherwise, one lost UDP packet and it is the end
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if soa == nil {
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success = false
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fmt.Printf("%s (%s) ", ips[j], err)
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fmt.Printf("%s (%s) ", ip, err)
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} else {
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if soa.Rcode != dns.RcodeSuccess {
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success = false
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fmt.Printf("%s (%s) ", ips[j], dns.Rcode_str[soa.Rcode])
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fmt.Printf("%s (%s) ", ips, dns.Rcode_str[soa.Rcode])
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} else {
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if len(soa.Answer) == 0 { /* May happen if the server is a recursor, not authoritative, since we query with RD=0 */
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success = false
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fmt.Printf("%s (0 answer) ", ips[j])
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fmt.Printf("%s (0 answer) ", ip)
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} else {
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rsoa := soa.Answer[0]
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switch rsoa.(type) {
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case *dns.RR_SOA:
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if soa.MsgHdr.Authoritative {
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/* TODO: test if all name servers have the same serial ? */
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fmt.Printf("%s (%d) ", ips[j], rsoa.(*dns.RR_SOA).Serial)
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fmt.Printf("%s (%d) ", ips, rsoa.(*dns.RR_SOA).Serial)
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} else {
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success = false
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fmt.Printf("%s (not authoritative) ", ips[j])
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fmt.Printf("%s (not authoritative) ", ips)
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}
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}
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}
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@ -161,12 +146,11 @@ func main() {
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}
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}
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if numNS == 0 {
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fmt.Printf("No NS records for \"%s\". It is probably a CNAME to a domain but not a zone\n", zone)
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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]))
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os.Exit(1)
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}
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if success {
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os.Exit(0)
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} else {
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os.Exit(1)
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}
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os.Exit(1)
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}
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