func main() {
c, err := dns.ClientConfigFromFile("/etc/resolv.conf")
if len(os.Args) != 2 || err != nil {
fmt.Printf("%s DOMAIN\n", os.Args[0])
os.Exit(1)
}
m := new(dns.Msg)
m.MsgHdr.RecursionDesired = true //only set this bit
m.Question = make([]dns.Question, 1)
m.Question[0] = dns.Question{os.Args[1], dns.TypeDNSKEY, dns.ClassINET}
d := new(dns.Conn)
d.RemoteAddr = c.Servers[0]
in, err := dns.SimpleQuery("udp", d, m)
if in != nil {
if in.Rcode != dns.RcodeSuccess {
fmt.Printf(" *** invalid answer name %s after DNSKEY query for %s\n", os.Args[1], os.Args[1])
os.Exit(1)
}
// Stuff must be in the answer section
for _, k := range in.Answer {
// Foreach key would need to provide a DS records, both sha1 and sha256
if key, ok := k.(*dns.RR_DNSKEY); ok {
ds := key.ToDS(dns.HashSHA1)
ds.Hdr.Ttl = 0
fmt.Printf("%v\n", ds)
ds = key.ToDS(dns.HashSHA256)
ds.Hdr.Ttl = 0
fmt.Printf("%v\n", ds)
}
}
} else {
fmt.Printf("*** error: %s\n", err.String())
}
}
// Create a dns message from a fingerprint string and
// a DNS question. The order of a string is always the same.
// .,IN,NS,QUERY,NOERROR,qr,aa,tc,RD,ad,ad,z,1,0,0,1,DO,4096,nsid
func (f *fingerprint) msg() *dns.Msg {
m := new(dns.Msg)
m.MsgHdr.Id = dns.Id()
m.Question = make([]dns.Question, 1)
m.Question[0] = dns.Question{f.Query.Name, f.Query.Qtype, f.Query.Qclass}
m.MsgHdr.Opcode = f.Opcode
m.MsgHdr.Rcode = f.Rcode
m.MsgHdr.Response = f.Response
m.MsgHdr.Authoritative = f.Authoritative
m.MsgHdr.Truncated = f.Truncated
m.MsgHdr.RecursionDesired = f.RecursionDesired
m.MsgHdr.AuthenticatedData = f.AuthenticatedData
m.MsgHdr.CheckingDisabled = f.CheckingDisabled
m.MsgHdr.Zero = f.Zero
if f.Do {
// Add an OPT section.
m.SetEdns0(0, true)
// We have added an OPT RR, set the size.
m.Extra[0].(*dns.RR_OPT).SetUDPSize(uint16(f.UDPSize))
if f.Nsid {
m.Extra[0].(*dns.RR_OPT).SetNsid("")
}
}
return m
}
func addresses(d *dns.Conn, name string) []string {
m := new(dns.Msg)
m.MsgHdr.RecursionDesired = true //only set this bit
m.Question = make([]dns.Question, 1)
var ips []string
m.Question[0] = dns.Question{os.Args[1], dns.TypeA, dns.ClassINET}
in, err := dns.SimpleQuery("udp", d, m)
if in == nil {
fmt.Printf("Nothing recevied: %s\n", err.String())
return nil
}
if in.Rcode != dns.RcodeSuccess {
return nil
}
// Stuff must be in the answer section
for _, a := range in.Answer {
ips = append(ips, a.(*dns.RR_A).A.String()+":53")
}
m.Question[0] = dns.Question{os.Args[1], dns.TypeAAAA, dns.ClassINET}
in, err = dns.SimpleQuery("udp", d, m)
if in == nil {
fmt.Printf("Nothing recevied: %s\n", err.String())
return ips
}
if in.Rcode != dns.RcodeSuccess {
return ips
}
for _, a := range in.Answer {
ips = append(ips, "["+a.(*dns.RR_AAAA).AAAA.String()+"]:53")
}
return ips
}
func main() {
if len(os.Args) != 2 {
fmt.Printf("%s NAMESERVER\n", os.Args[0])
os.Exit(1)
}
conf, _ := dns.ClientConfigFromFile("/etc/resolv.conf")
m := new(dns.Msg)
m.Question = make([]dns.Question, 1)
c := dns.NewClient()
addr := addresses(conf, c, os.Args[1])
if len(addr) == 0 {
fmt.Printf("No address found for %s\n", os.Args[1])
os.Exit(1)
}
for _, a := range addr {
m.Question[0] = dns.Question{"version.bind.", dns.TypeTXT, dns.ClassCHAOS}
in := c.Exchange(m, a)
if in != nil && in.Answer != nil {
fmt.Printf("%v\n", in.Answer[0])
}
m.Question[0] = dns.Question{"hostname.bind.", dns.TypeTXT, dns.ClassCHAOS}
in = c.Exchange(m, a)
if in != nil && in.Answer != nil {
fmt.Printf("%v\n", in.Answer[0])
}
}
}
func main() {
c, _ := dns.ClientConfigFromFile("/etc/resolv.conf")
if len(os.Args) != 2 {
fmt.Printf("%s DOMAIN\n", os.Args[0])
os.Exit(1)
}
m := new(dns.Msg)
m.Question = make([]dns.Question, 1)
d := new(dns.Conn)
d.RemoteAddr = c.Servers[0]
for _, a := range addresses(d, os.Args[0]) {
d.RemoteAddr = a
if err := d.Dial("udp"); err != nil {
fmt.Printf("%v\n", err)
os.Exit(1)
}
m.Question[0] = dns.Question{"version.bind.", dns.TypeTXT, dns.ClassCHAOS}
in, _ := dns.SimpleQuery("udp", d, m)
if in != nil && in.Answer != nil {
fmt.Printf("%v\n", in.Answer[0])
}
m.Question[0] = dns.Question{"hostname.bind.", dns.TypeTXT, dns.ClassCHAOS}
in, _ = dns.SimpleQuery("udp", d, m)
if in != nil && in.Answer != nil {
fmt.Printf("%v\n", in.Answer[0])
}
}
}
func newConnMsg(qname, nameserver string, attempts int, qtype, qclass uint16, aa, ad, cd, rd, dnssec, nsid bool) (*dns.Conn, *dns.Msg) {
d := new(dns.Conn)
d.RemoteAddr = nameserver
d.Attempts = attempts
m := new(dns.Msg)
m.MsgHdr.Authoritative = aa
m.MsgHdr.AuthenticatedData = ad
m.MsgHdr.CheckingDisabled = cd
m.MsgHdr.RecursionDesired = rd
m.Question = make([]dns.Question, 1)
if dnssec || nsid {
opt := new(dns.RR_OPT)
opt.SetDo()
opt.SetVersion(0)
opt.SetUDPSize(dns.DefaultMsgSize)
if nsid {
opt.SetNsid("")
}
m.Extra = make([]dns.RR, 1)
m.Extra[0] = opt
}
m.Question[0] = dns.Question{qname, qtype, qclass}
m.Id = dns.Id()
return d, m
}
func reply(c *dns.Conn, in *dns.Msg) []byte {
m := new(dns.Msg)
m.SetReply(in)
m.Question = make([]dns.Question, 1)
m.Answer = make([]dns.RR, 1)
m.Extra = make([]dns.RR, 1)
// Copy the question.
m.Question[0] = in.Question[0]
// Some foo to check if we are called through ip6 or ip4.
// We add the correct reply RR.
var ad net.IP
if c.UDP != nil {
ad = c.Addr.(*net.UDPAddr).IP
} else {
ad = c.Addr.(*net.TCPAddr).IP
}
if ad.To4() != nil {
r := new(dns.RR_A)
r.Hdr = dns.RR_Header{Name: "whoami.miek.nl.", Rrtype: dns.TypeA, Class: dns.ClassINET, Ttl: 0}
r.A = ad
m.Answer[0] = r
} else {
r := new(dns.RR_AAAA)
r.Hdr = dns.RR_Header{Name: "whoami.miek.nl.", Rrtype: dns.TypeAAAA, Class: dns.ClassINET, Ttl: 0}
r.AAAA = ad
m.Answer[0] = r
}
t := new(dns.RR_TXT)
t.Hdr = dns.RR_Header{Name: "whoami.miek.nl.", Rrtype: dns.TypeTXT, Class: dns.ClassINET, Ttl: 0}
if c.TCP != nil {
t.Txt = "Port: " + strconv.Itoa(c.Port) + " (tcp)"
} else {
t.Txt = "Port: " + strconv.Itoa(c.Port) + " (udp)"
}
m.Extra[0] = t
b, _ := m.Pack()
return b
}
func main() {
if len(os.Args) != 2 {
fmt.Printf("%s DOMAIN\n", os.Args[0])
os.Exit(1)
}
d := new(dns.Conn)
c, err := dns.ClientConfigFromFile("/etc/resolv.conf")
// Errorchecking
d.RemoteAddr = c.Servers[0]
m := new(dns.Msg)
m.Id = dns.Id()
m.MsgHdr.RecursionDesired = true
m.Question = make([]dns.Question, 1)
m.Question[0] = dns.Question{os.Args[1], dns.TypeMX, dns.ClassINET}
err = d.Dial("udp")
if err != nil {
fmt.Printf("*** error: %s\n", err.String())
os.Exit(1)
}
in, err := dns.SimpleQuery("udp", d, m)
if in != nil {
if in.Rcode != dns.RcodeSuccess {
fmt.Printf(" *** invalid answer name %s after MX query for %s\n", os.Args[1], os.Args[1])
os.Exit(1)
}
// Stuff must be in the answer section
for _, a := range in.Answer {
fmt.Printf("%v\n", a)
}
} else {
fmt.Printf("*** error: %s\n", err.String())
}
}
func main() {
dnssec := flag.Bool("dnssec", false, "request DNSSEC records")
query := flag.Bool("question", false, "show question")
short := flag.Bool("short", false, "abbreviate long DNSSEC records")
check := flag.Bool("check", false, "check internal DNSSEC consistency")
six := flag.Bool("6", false, "use IPv6 only")
four := flag.Bool("4", false, "use IPv4 only")
anchor := flag.String("anchor", "", "use the DNSKEY in this file for interal DNSSEC consistency")
tsig := flag.String("tsig", "", "request tsig with key: [hmac:]name:key")
port := flag.Int("port", 53, "port number to use")
aa := flag.Bool("aa", false, "set AA flag in query")
ad := flag.Bool("ad", false, "set AD flag in query")
cd := flag.Bool("cd", false, "set CD flag in query")
rd := flag.Bool("rd", true, "set RD flag in query")
fallback := flag.Bool("fallback", false, "fallback to 4096 bytes bufsize and after that TCP")
tcp := flag.Bool("tcp", false, "TCP mode")
nsid := flag.Bool("nsid", false, "set edns nsid option")
client := flag.String("client", "", "set edns client-subnet option")
flag.Usage = func() {
fmt.Fprintf(os.Stderr, "Usage: %s [@server] [qtype] [qclass] [name ...]\n", os.Args[0])
flag.PrintDefaults()
}
conf, _ := dns.ClientConfigFromFile("/etc/resolv.conf")
nameserver := "@" + conf.Servers[0]
qtype := uint16(0)
qclass := uint16(dns.ClassINET) // Default qclass
var qname []string
flag.Parse()
if *anchor != "" {
f, err := os.Open(*anchor)
if err != nil {
fmt.Fprintf(os.Stderr, "Failure to open %s: %s\n", *anchor, err.Error())
}
r, err := dns.ReadRR(f, *anchor)
if err != nil {
fmt.Fprintf(os.Stderr, "Failure to read an RR from %s: %s\n", *anchor, err.Error())
}
if k, ok := r.(*dns.RR_DNSKEY); !ok {
fmt.Fprintf(os.Stderr, "No DNSKEY read from %s\n", *anchor)
} else {
dnskey = k
}
}
Flags:
for i := 0; i < flag.NArg(); i++ {
// If it starts with @ it is a nameserver
if flag.Arg(i)[0] == '@' {
nameserver = flag.Arg(i)
continue Flags
}
// First class, then type, to make ANY queries possible
// And if it looks like type, it is a type
if k, ok := dns.Str_rr[strings.ToUpper(flag.Arg(i))]; ok {
qtype = k
switch qtype {
case dns.TypeAXFR:
fmt.Fprintf(os.Stderr, "AXFR not supported\n")
return
case dns.TypeIXFR:
fmt.Fprintf(os.Stderr, "AXFR not supported\n")
return
}
continue Flags
}
// If it looks like a class, it is a class
if k, ok := dns.Str_class[strings.ToUpper(flag.Arg(i))]; ok {
qclass = k
continue Flags
}
// If it starts with TYPExxx it is unknown rr
if strings.HasPrefix(flag.Arg(i), "TYPE") {
i, e := strconv.Atoi(string([]byte(flag.Arg(i))[4:]))
if e == nil {
qtype = uint16(i)
switch qtype {
case dns.TypeAXFR:
fmt.Fprintf(os.Stderr, "AXFR not supported\n")
return
case dns.TypeIXFR:
fmt.Fprintf(os.Stderr, "AXFR not supported\n")
return
}
continue Flags
}
}
// Anything else is a qname
qname = append(qname, flag.Arg(i))
}
if len(qname) == 0 {
qname = make([]string, 1)
qname[0] = "."
qtype = dns.TypeNS
}
if qtype == 0 {
qtype = dns.TypeA
}
nameserver = string([]byte(nameserver)[1:]) // chop off @
nameserver += ":" + strconv.Itoa(*port)
// We use the async query handling, just to show how it is to be used.
c := new(dns.Client)
if *tcp {
c.Net = "tcp"
if *four {
c.Net = "tcp4"
}
if *six {
c.Net = "tcp6"
}
} else {
c.Net = "udp"
if *four {
c.Net = "udp4"
}
if *six {
c.Net = "udp6"
}
}
m := new(dns.Msg)
m.MsgHdr.Authoritative = *aa
m.MsgHdr.AuthenticatedData = *ad
m.MsgHdr.CheckingDisabled = *cd
m.MsgHdr.RecursionDesired = *rd
m.Question = make([]dns.Question, 1)
if *dnssec || *nsid || *client != "" {
o := new(dns.RR_OPT)
o.Hdr.Name = "."
o.Hdr.Rrtype = dns.TypeOPT
if *dnssec {
o.SetDo()
o.SetUDPSize(dns.DefaultMsgSize)
}
if *nsid {
e := new(dns.EDNS0_NSID)
e.Code = dns.EDNS0NSID
o.Option = append(o.Option, e)
// NSD will not return nsid when the udp message size is too small
o.SetUDPSize(dns.DefaultMsgSize)
}
if *client != "" {
e := new(dns.EDNS0_SUBNET)
e.Code = dns.EDNS0SUBNET
e.SourceScope = 0
e.Address = net.ParseIP(*client)
if e.Address == nil {
fmt.Fprintf(os.Stderr, "Failure to parse IP address: %s\n", *client)
return
}
e.Family = 1 // IP4
e.SourceNetmask = net.IPv4len * 8
if e.Address.To4() == nil {
e.Family = 2 // IP6
e.SourceNetmask = net.IPv6len * 8
}
o.Option = append(o.Option, e)
}
m.Extra = append(m.Extra, o)
}
for i, v := range qname {
m.Question[0] = dns.Question{v, qtype, qclass}
m.Id = dns.Id()
if *query {
fmt.Printf("%s", m.String())
fmt.Printf("\n;; size: %d bytes\n\n", m.Len())
}
// Add tsig
if *tsig != "" {
if algo, name, secret, ok := tsigKeyParse(*tsig); ok {
m.SetTsig(name, algo, 300, time.Now().Unix())
c.TsigSecret = map[string]string{name: secret}
} else {
fmt.Fprintf(os.Stderr, "tsig key data error\n")
return
}
}
c.DoRtt(m, nameserver, nil, func(m, r *dns.Msg, rtt time.Duration, e error, data interface{}) {
defer func() {
if i == len(qname)-1 {
os.Exit(0)
}
}()
Redo:
if r == nil {
return
}
if r.Rcode != dns.RcodeSuccess {
return
}
if r.Id != m.Id {
fmt.Printf("Id mismatch\n")
return
}
if r.MsgHdr.Truncated && *fallback {
if c.Net != "tcp" {
if !*dnssec {
fmt.Printf(";; Truncated, trying %d bytes bufsize\n", dns.DefaultMsgSize)
o := new(dns.RR_OPT)
o.Hdr.Name = "."
o.Hdr.Rrtype = dns.TypeOPT
o.SetUDPSize(dns.DefaultMsgSize)
m.Extra = append(m.Extra, o)
r, rtt, e = c.ExchangeRtt(m, nameserver)
*dnssec = true
goto Redo
} else {
// First EDNS, then TCP
fmt.Printf(";; Truncated, trying TCP\n")
c.Net = "tcp"
r, rtt, e = c.ExchangeRtt(m, nameserver)
goto Redo
}
}
}
if r.MsgHdr.Truncated && !*fallback {
fmt.Printf(";; Truncated\n")
}
if *check {
sigCheck(r, nameserver, *tcp)
nsecCheck(r)
//dns.AssertDelegationSigner(r.Reply, nil)
}
if *short {
r = shortMsg(r)
}
fmt.Printf("%v", r)
fmt.Printf("\n;; query time: %.3d µs, server: %s(%s), size: %d bytes\n", rtt/1e3, nameserver, c.Net, r.Size)
})
}
select {}
}
func main() {
dnssec := flag.Bool("dnssec", false, "request DNSSEC records")
query := flag.Bool("question", false, "show question")
short := flag.Bool("short", false, "abbreviate long DNSSEC records")
check := flag.Bool("check", false, "check internal DNSSEC consistency")
anchor := flag.String("anchor", "", "use the DNSKEY in this file for checking consistency")
port := flag.Int("port", 53, "port number to use")
aa := flag.Bool("aa", false, "set AA flag in query")
ad := flag.Bool("ad", false, "set AD flag in query")
cd := flag.Bool("cd", false, "set CD flag in query")
rd := flag.Bool("rd", true, "unset RD flag in query")
tcp := flag.Bool("tcp", false, "TCP mode")
nsid := flag.Bool("nsid", false, "ask for NSID")
flag.Usage = func() {
fmt.Fprintf(os.Stderr, "Usage: %s [@server] [qtype] [qclass] [name ...]\n", os.Args[0])
flag.PrintDefaults()
}
conf, _ := dns.ClientConfigFromFile("/etc/resolv.conf")
nameserver := "@" + conf.Servers[0]
qtype := uint16(0)
qclass := uint16(dns.ClassINET) // Default qclass
var qname []string
flag.Parse()
if *anchor != "" {
f, err := os.Open(*anchor)
if err != nil {
fmt.Fprintf(os.Stderr, "Failure to open %s: %s\n", *anchor, err.Error())
}
r, err := dns.ReadRR(f, *anchor)
if err != nil {
fmt.Fprintf(os.Stderr, "Failure to read an RR from %s: %s\n", *anchor, err.Error())
}
if k, ok := r.(*dns.RR_DNSKEY); !ok {
fmt.Fprintf(os.Stderr, "No DNSKEY read from %s\n", *anchor)
} else {
dnskey = k
}
}
Flags:
for i := 0; i < flag.NArg(); i++ {
// If it starts with @ it is a nameserver
if flag.Arg(i)[0] == '@' {
nameserver = flag.Arg(i)
continue Flags
}
// First class, then type, to make ANY queries possible
// And if it looks like type, it is a type
if k, ok := dns.Str_rr[strings.ToUpper(flag.Arg(i))]; ok {
qtype = k
continue Flags
}
// If it looks like a class, it is a class
if k, ok := dns.Str_class[strings.ToUpper(flag.Arg(i))]; ok {
qclass = k
continue Flags
}
// If it starts with TYPExxx it is unknown rr
if strings.HasPrefix(flag.Arg(i), "TYPE") {
i, e := strconv.Atoi(string([]byte(flag.Arg(i))[4:]))
if e == nil {
qtype = uint16(i)
continue Flags
}
}
// Anything else is a qname
qname = append(qname, flag.Arg(i))
}
if len(qname) == 0 {
qname = make([]string, 1)
qname[0] = "."
qtype = dns.TypeNS
}
if qtype == 0 {
qtype = dns.TypeA
}
nameserver = string([]byte(nameserver)[1:]) // chop off @
nameserver += ":" + strconv.Itoa(*port)
// ipv6 todo
// We use the async query handling, just to show how
// it is to be used.
dns.HandleQueryFunc(".", q)
dns.ListenAndQuery(nil, nil)
c := dns.NewClient()
if *tcp {
c.Net = "tcp"
}
m := new(dns.Msg)
m.MsgHdr.Authoritative = *aa
m.MsgHdr.AuthenticatedData = *ad
m.MsgHdr.CheckingDisabled = *cd
m.MsgHdr.RecursionDesired = *rd
m.Question = make([]dns.Question, 1)
if *dnssec || *nsid {
o := new(dns.RR_OPT)
o.Hdr.Name = "."
o.Hdr.Rrtype = dns.TypeOPT
if *dnssec {
o.SetDo()
o.SetUDPSize(dns.DefaultMsgSize)
}
if *nsid {
o.SetNsid("")
}
m.Extra = append(m.Extra, o)
}
for _, v := range qname {
m.Question[0] = dns.Question{v, qtype, qclass}
m.Id = dns.Id()
if *query {
fmt.Printf("%s\n", m.String())
}
c.Do(m, nameserver)
}
i := 0
forever:
for {
select {
case r := <-dns.DefaultReplyChan:
if r.Reply != nil {
if r.Reply.Rcode == dns.RcodeSuccess {
if r.Request.Id != r.Reply.Id {
fmt.Printf("Id mismatch\n")
}
}
if *check {
sigCheck(r.Reply, nameserver, *tcp)
nsecCheck(r.Reply)
}
if *short {
r.Reply = shortMsg(r.Reply)
}
fmt.Printf("%v", r.Reply)
}
i++
if i == len(qname) {
break forever
}
}
}
}
func main() {
var dnssec *bool = flag.Bool("dnssec", false, "request DNSSEC records")
var query *bool = flag.Bool("question", false, "show question")
var short *bool = flag.Bool("short", false, "abbriate long DNSKEY and RRSIG RRs")
var aa *bool = flag.Bool("aa", false, "set AA flag in query")
var ad *bool = flag.Bool("ad", false, "set AD flag in query")
var cd *bool = flag.Bool("cd", false, "set CD flag in query")
var rd *bool = flag.Bool("rd", true, "unset RD flag in query")
var tcp *bool = flag.Bool("tcp", false, "TCP mode")
var nsid *bool = flag.Bool("nsid", false, "ask for NSID")
flag.Usage = func() {
fmt.Fprintf(os.Stderr, "Usage: %s [@server(:port)] [qtype] [qclass] [name ...]\n", os.Args[0])
flag.PrintDefaults()
}
// Need to think about it... Config
conf, _ := dns.ClientConfigFromFile("/etc/resolv.conf")
nameserver := "@" + conf.Servers[0]
qtype := uint16(0)
qclass := uint16(dns.ClassINET) // Default qclass
var qname []string
flag.Parse()
Flags:
for i := 0; i < flag.NArg(); i++ {
// If it starts with @ it is a nameserver
if flag.Arg(i)[0] == '@' {
nameserver = flag.Arg(i)
continue Flags
}
// First class, then type, to make ANY queries possible
// And if it looks like type, it is a type
for k, v := range dns.Rr_str {
if v == strings.ToUpper(flag.Arg(i)) {
qtype = k
continue Flags
}
}
// If it looks like a class, it is a class
for k, v := range dns.Class_str {
if v == strings.ToUpper(flag.Arg(i)) {
qclass = k
continue Flags
}
}
// If it starts with TYPExxx it is unknown rr
if strings.HasPrefix(flag.Arg(i), "TYPE") {
i, e := strconv.Atoi(string([]byte(flag.Arg(i))[4:]))
if e == nil {
qtype = uint16(i)
continue Flags
}
}
// Anything else is a qname
qname = append(qname, flag.Arg(i))
}
if len(qname) == 0 {
qname = make([]string, 1)
qname[0] = "."
qtype = dns.TypeNS
}
if qtype == 0 {
qtype = dns.TypeA
}
nameserver = string([]byte(nameserver)[1:]) // chop off @
if !strings.HasSuffix(nameserver, ":53") {
nameserver += ":53"
}
// ipv6 todo
// We use the async query handling, just to show how
// it is to be used.
dns.HandleQueryFunc(".", q)
dns.ListenAndQuery(nil, nil)
c := dns.NewClient()
if *tcp {
c.Net = "tcp"
}
m := new(dns.Msg)
m.MsgHdr.Authoritative = *aa
m.MsgHdr.AuthenticatedData = *ad
m.MsgHdr.CheckingDisabled = *cd
m.MsgHdr.RecursionDesired = *rd
m.Question = make([]dns.Question, 1)
if *dnssec || *nsid {
opt := dns.NewRR(dns.TypeOPT).(*dns.RR_OPT)
opt.Hdr.Rrtype = 0
opt.SetDo()
opt.SetVersion(0)
opt.SetUDPSize(dns.DefaultMsgSize)
if *nsid {
opt.SetNsid("")
}
m.Extra = make([]dns.RR, 1)
m.Extra[0] = opt
}
for _, v := range qname {
m.Question[0] = dns.Question{v, qtype, qclass}
m.Id = dns.Id()
if *query {
fmt.Printf("%s\n", m.String())
}
c.Do(m, nameserver)
}
i := 0
forever:
for {
select {
case r := <-dns.DefaultReplyChan:
if r[1] != nil {
if r[0].Id != r[1].Id {
fmt.Printf("Id mismatch\n")
}
if *short {
r[1] = shortMsg(r[1])
}
fmt.Printf("%v", r[1])
}
i++
if i == len(qname) {
break forever
}
}
}
}
func main() {
dnssec := flag.Bool("dnssec", false, "request DNSSEC records")
query := flag.Bool("question", false, "show question")
short := flag.Bool("short", false, "abbreviate long DNSSEC records")
check := flag.Bool("check", false, "check internal DNSSEC consistency")
six := flag.Bool("6", false, "use IPv6 only")
four := flag.Bool("4", false, "use IPv4 only")
anchor := flag.String("anchor", "", "use the DNSKEY in this file for interal DNSSEC consistency")
tsig := flag.String("tsig", "", "request tsig with key: [hmac:]name:key")
port := flag.Int("port", 53, "port number to use")
aa := flag.Bool("aa", false, "set AA flag in query")
ad := flag.Bool("ad", false, "set AD flag in query")
cd := flag.Bool("cd", false, "set CD flag in query")
rd := flag.Bool("rd", true, "set RD flag in query")
fallback := flag.Bool("fallback", false, "fallback to 4096 bytes bufsize and after that TCP")
tcp := flag.Bool("tcp", false, "TCP mode")
nsid := flag.Bool("nsid", false, "ask for NSID")
flag.Usage = func() {
fmt.Fprintf(os.Stderr, "Usage: %s [@server] [qtype] [qclass] [name ...]\n", os.Args[0])
flag.PrintDefaults()
}
conf, _ := dns.ClientConfigFromFile("/etc/resolv.conf")
nameserver := "@" + conf.Servers[0]
qtype := uint16(0)
qclass := uint16(dns.ClassINET) // Default qclass
var qname []string
flag.Parse()
if *anchor != "" {
f, err := os.Open(*anchor)
if err != nil {
fmt.Fprintf(os.Stderr, "Failure to open %s: %s\n", *anchor, err.Error())
}
r, err := dns.ReadRR(f, *anchor)
if err != nil {
fmt.Fprintf(os.Stderr, "Failure to read an RR from %s: %s\n", *anchor, err.Error())
}
if k, ok := r.(*dns.RR_DNSKEY); !ok {
fmt.Fprintf(os.Stderr, "No DNSKEY read from %s\n", *anchor)
} else {
dnskey = k
}
}
Flags:
for i := 0; i < flag.NArg(); i++ {
// If it starts with @ it is a nameserver
if flag.Arg(i)[0] == '@' {
nameserver = flag.Arg(i)
continue Flags
}
// First class, then type, to make ANY queries possible
// And if it looks like type, it is a type
if k, ok := dns.Str_rr[strings.ToUpper(flag.Arg(i))]; ok {
qtype = k
switch qtype {
case dns.TypeAXFR:
fmt.Fprintf(os.Stderr, "AXFR not supported\n")
return
case dns.TypeIXFR:
fmt.Fprintf(os.Stderr, "AXFR not supported\n")
return
}
continue Flags
}
// If it looks like a class, it is a class
if k, ok := dns.Str_class[strings.ToUpper(flag.Arg(i))]; ok {
qclass = k
continue Flags
}
// If it starts with TYPExxx it is unknown rr
if strings.HasPrefix(flag.Arg(i), "TYPE") {
i, e := strconv.Atoi(string([]byte(flag.Arg(i))[4:]))
if e == nil {
qtype = uint16(i)
switch qtype {
case dns.TypeAXFR:
fmt.Fprintf(os.Stderr, "AXFR not supported\n")
return
case dns.TypeIXFR:
fmt.Fprintf(os.Stderr, "AXFR not supported\n")
return
}
continue Flags
}
}
// Anything else is a qname
qname = append(qname, flag.Arg(i))
}
if len(qname) == 0 {
qname = make([]string, 1)
qname[0] = "."
qtype = dns.TypeNS
}
if qtype == 0 {
qtype = dns.TypeA
}
nameserver = string([]byte(nameserver)[1:]) // chop off @
nameserver += ":" + strconv.Itoa(*port)
// We use the async query handling, just to show how it is to be used.
dns.HandleQuery(".", q)
dns.ListenAndQuery(nil)
c := new(dns.Client)
if *tcp {
c.Net = "tcp"
if *four {
c.Net = "tcp4"
}
if *six {
c.Net = "tcp6"
}
} else {
c.Net = "udp"
if *four {
c.Net = "udp4"
}
if *six {
c.Net = "udp6"
}
}
m := new(dns.Msg)
m.MsgHdr.Authoritative = *aa
m.MsgHdr.AuthenticatedData = *ad
m.MsgHdr.CheckingDisabled = *cd
m.MsgHdr.RecursionDesired = *rd
m.Question = make([]dns.Question, 1)
if *dnssec || *nsid {
o := new(dns.RR_OPT)
o.Hdr.Name = "."
o.Hdr.Rrtype = dns.TypeOPT
if *dnssec {
o.SetDo()
o.SetUDPSize(dns.DefaultMsgSize)
}
if *nsid {
o.SetNsid("")
}
m.Extra = append(m.Extra, o)
}
for _, v := range qname {
m.Question[0] = dns.Question{v, qtype, qclass}
m.Id = dns.Id()
if *query {
fmt.Printf("%s\n", m.String())
}
// Add tsig
if *tsig != "" {
if algo, name, secret, ok := tsigKeyParse(*tsig); ok {
m.SetTsig(name, algo, 300, time.Now().Unix())
c.TsigSecret = map[string]string{name: secret}
} else {
fmt.Fprintf(os.Stderr, "tsig key data error\n")
return
}
}
c.Do(m, nameserver)
}
i := 0
forever:
for {
select {
case r := <-c.Reply:
if r.Reply != nil {
if r.Reply.Rcode == dns.RcodeSuccess {
if r.Request.Id != r.Reply.Id {
fmt.Printf("Id mismatch\n")
}
}
if r.Reply.MsgHdr.Truncated && *fallback {
if c.Net != "tcp" {
if !*dnssec {
fmt.Printf(";; Truncated, trying %d bytes bufsize\n", dns.DefaultMsgSize)
o := new(dns.RR_OPT)
o.Hdr.Name = "."
o.Hdr.Rrtype = dns.TypeOPT
o.SetUDPSize(dns.DefaultMsgSize)
m.Extra = append(m.Extra, o)
*dnssec = true
c.Do(m, nameserver)
break
} else {
// First EDNS, then TCP
fmt.Printf(";; Truncated, trying TCP\n")
c.Net = "tcp"
c.Do(m, nameserver)
break
}
}
}
if r.Reply.MsgHdr.Truncated && !*fallback {
fmt.Printf(";; Truncated\n")
}
if *check {
sigCheck(r.Reply, nameserver, *tcp)
nsecCheck(r.Reply)
}
if *short {
r.Reply = shortMsg(r.Reply)
}
fmt.Printf("%v", r.Reply)
fmt.Printf("\n;; query time: %.3d µs, server: %s(%s)\n", r.Rtt/1e3, r.RemoteAddr, r.RemoteAddr.Network())
// Server maybe
}
i++
if i == len(qname) {
break forever
}
}
}
}