// Handles requests with questions for records of type `AAAA`.
// If IPv6 routing is enabled, the request will undergo the same
// treatment as `A` types in `handleV4Hijack()`; otherwise an empty
// packet is sent back as a reply.
func handleV6Hijack(w dns.ResponseWriter, req *dns.Msg) *dns.Msg {
var m *dns.Msg
// if an IPv6 gateway address was specified, AAAA records will be forwarded
// and processed; otherwise a fake reply is sent back telling the user agent
// that there are no IPv6 addresses present at this address
if routev6 {
// forward request to the specified nameservers
m = getServerReply(w, req)
// iterate through the answers in the reply and handle based on type
for _, ans := range m.Answer {
if ans.Header().Rrtype == dns.TypeAAAA {
// add IP address to local list and then routing table
ip := ans.(*dns.AAAA).AAAA.String()
routedv6[ip] = struct{}{}
log.Print("Re-routing ", ip, " for ", ans.Header().Name, "/", dns.Type(ans.Header().Rrtype).String())
if runtime.GOOS == "windows" {
runAndLog(router, "add", ip+"/128", *gateway6)
} else {
runAndLog(router, "add", ip+"/128", "gw", *gateway6)
}
} else if ans.Header().Rrtype == dns.TypeA {
// sanity check for now, shouldn't happen afaik
log.Print("WARNING: A response in ", ans.Header().Name, "/AAAA")
}
}
} else {
if *verbose {
log.Print("Hijacking ", req.Question[0].Name, "/", dns.Type(req.Question[0].Qtype).String())
}
// create new empty reply packet with no errors indicated
// if `RCODE` is set to `NXDOMAIN` instead of the current empty packet method,
// some web browsers (e.g. Chrome) will display an error message stating
// `DNS_PROBE_FINISHED_NXDOMAIN`, even though a request for `A` records types is
// sent by the user agent and properly replied to (with addresses) by the server
m = getEmptyMsg(w, req, 0)
}
return m
}
// Forwards a DNS request to the specified nameservers. On success, the
// original reply packet will be returned to the caller. On failure, a
// new packet will be returned with `RCODE` set to `SERVFAIL`.
// Even though the original `ResponseWriter` object is taken as an argument,
// this function does not send a reply to the client. Instead, the
// packet is returned for further processing by the caller.
func getServerReply(w dns.ResponseWriter, req *dns.Msg) *dns.Msg {
if *verbose {
log.Print("Forwarding ", req.Question[0].Name, "/", dns.Type(req.Question[0].Qtype).String())
}
// create a new DNS client
client := &dns.Client{Net: "udp", ReadTimeout: 4 * time.Second, WriteTimeout: 4 * time.Second, SingleInflight: true}
if _, tcp := w.RemoteAddr().(*net.TCPAddr); tcp {
client.Net = "tcp"
}
var r *dns.Msg
var err error
// loop through the specified nameservers and forward them the request
// the request ID is used as a starting point in order to introduce at least
// some element of randomness, instead of always hitting the first nameserver
for i := 0; i < len(nameservers); i++ {
r, _, err = client.Exchange(req, nameservers[(int(req.Id)+i)%len(nameservers)])
if err == nil {
r.Compress = true
return r
}
}
log.Print("Failed to forward request.", err)
return getEmptyMsg(w, req, dns.RcodeServerFailure)
}
func TestLookup(t *testing.T) {
for _, serv := range services {
set(t, etc, serv.Key, 0, serv)
defer delete(t, etc, serv.Key)
}
for _, tc := range dnsTestCases {
m := tc.Msg()
rec := middleware.NewResponseRecorder(&test.ResponseWriter{})
_, err := etc.ServeDNS(ctxt, rec, m)
if err != nil {
t.Errorf("expected no error, got: %v for %s %s\n", err, m.Question[0].Name, dns.Type(m.Question[0].Qtype))
return
}
resp := rec.Msg()
sort.Sort(test.RRSet(resp.Answer))
sort.Sort(test.RRSet(resp.Ns))
sort.Sort(test.RRSet(resp.Extra))
if !test.Header(t, tc, resp) {
t.Logf("%v\n", resp)
continue
}
if !test.Section(t, tc, test.Answer, resp.Answer) {
t.Logf("%v\n", resp)
}
if !test.Section(t, tc, test.Ns, resp.Ns) {
t.Logf("%v\n", resp)
}
if !test.Section(t, tc, test.Extra, resp.Extra) {
t.Logf("%v\n", resp)
}
}
}
// Handles requests with questions for records of type `A`.
// Forwards the request to the specified nameservers and returns the
// result to the caller to be sent back to the client. However, before
// a reply is sent back, the IP addresses found within the response
// packet are added to the routing table.
func handleV4Hijack(w dns.ResponseWriter, req *dns.Msg) *dns.Msg {
// forward request to the specified nameservers
m := getServerReply(w, req)
// iterate through the answers in the reply and handle based on type
for _, ans := range m.Answer {
if ans.Header().Rrtype == dns.TypeA {
// add IP address to local list and then routing table
ip := ans.(*dns.A).A.String()
routedv4[ip] = struct{}{}
log.Print("Re-routing ", ip, " for ", ans.Header().Name, "/", dns.Type(ans.Header().Rrtype).String())
if runtime.GOOS == "windows" {
runAndLog(router, "add", ip+"/32", *gateway4)
} else {
runAndLog(router, "add", ip+"/32", "gw", *gateway4)
}
} else if ans.Header().Rrtype == dns.TypeAAAA {
// sanity check for now, shouldn't happen afaik
log.Print("WARNING: AAAA response in ", ans.Header().Name, "/A")
}
}
return m
}
func dnsQueryServe(cfg *Config, cache *dnscache.Cache, w dns.ResponseWriter, req *dns.Msg) {
start := time.Now()
if req.MsgHdr.Response == true { // supposed responses sent to us are bogus
q := req.Question[0]
log.Printf("DNS Query IS BOGUS %s %s from %s.\n", q.Name, dns.Type(q.Qtype).String(), w.RemoteAddr())
return
}
// TODO: handle AXFR/IXFR (full and incremental) *someday* for use by non-netcore slaves
// ... also if we do that, also handle sending NOTIFY to listed slaves attached to the SOA record
// Process questions in parallel
pending := make([]chan []dns.RR, 0, len(req.Question)) // Slice of answer channels
for i := range req.Question {
q := &req.Question[i]
log.Printf("DNS Query [%d/%d] %s %s from %s\n", i+1, len(req.Question), q.Name, dns.Type(q.Qtype).String(), w.RemoteAddr())
pending = append(pending, serveQuestion(cfg, cache, q, start))
}
// Assemble answers according to the order of the questions
var answers []dns.RR
for _, ch := range pending {
answers = append(answers, <-ch...)
}
for _, answer := range answers {
log.Printf(" [%9.04fms] ANSWER %s\n", msElapsed(start, time.Now()), answer.String())
}
if len(answers) > 0 {
//log.Printf("OUR DATA: [%+v]\n", answerMsg)
answerMsg := prepareAnswerMsg(req, answers)
w.WriteMsg(answerMsg)
return
}
//log.Printf("NO DATA: [%+v]\n", answerMsg)
failMsg := prepareFailureMsg(req)
w.WriteMsg(failMsg)
}
func fetchEntry(cfg *Config, q *dns.Question, rrType uint16) chan dnsEntryResult {
out := make(chan dnsEntryResult)
go func() {
entry, err := cfg.db.GetDNS(q.Name, dns.Type(rrType).String())
out <- dnsEntryResult{
Entry: entry,
RType: rrType,
Err: err,
}
}()
return out
}
func isForeign(r *dns.Msg) (foreign bool) {
foreign = true
check_ip:
for _, answer := range r.Answer {
if "A" == dns.Type(answer.Header().Rrtype).String() {
for _, ipNet := range netRange {
a := answer.(*dns.A).A
if ipNet.Contains(a) {
foreign = false
break check_ip
}
}
}
}
return
}
// Create a dns answer with
func (h *ENUMHandler) createAnswer(request *dns.Msg) (answer *dns.Msg, err error) {
if len(request.Question) != 1 {
err = errors.New("Received more than one question")
return
}
question := request.Question[0]
if question.Qtype != dns.TypeNAPTR {
err = errors.New("Received an unsupported query type '" + dns.Type(question.Qtype).String() + "'")
return
}
var number uint64
if number, err = extractE164FromName(question.Name); err != nil {
return
}
var numberrange enum.NumberRange
h.Trace.Printf("backend.RangesBetween(%d, %d, 1)", number, number)
ranges, err := (*h.Backend).RangesBetween(number, number, 1)
if err != nil || len(ranges) != 1 {
return
}
numberrange = ranges[0]
answer = h.answerForRequest(request)
// Create and populate the NAPTR answers.
for _, record := range numberrange.Records {
naptr := new(dns.NAPTR)
naptr.Hdr = dns.RR_Header{Name: question.Name, Rrtype: question.Qtype, Class: question.Qclass, Ttl: 0}
naptr.Regexp = record.Regexp
naptr.Preference = record.Preference
naptr.Service = record.Service
naptr.Flags = record.Flags
naptr.Order = record.Order
naptr.Replacement = record.Replacement
answer.Answer = append(answer.Answer, naptr)
}
return
}
// Convert some DNS records into a route53 ResourceRecordSet. The records should have been
// previously grouped by matching name, type and (if applicable) identifier.
func ConvertBindToRRSet(records []dns.RR) *route53.ResourceRecordSet {
rrs := []*route53.ResourceRecord{}
for _, record := range records {
if rr, ok := record.(*dns.PrivateRR); ok {
return ConvertAliasToRRSet(rr)
} else if rec, ok := record.(*AWSRR); ok {
rrs = append(rrs, ConvertBindToRR(rec.RR)...)
} else {
rrs = append(rrs, ConvertBindToRR(record)...)
}
}
if len(rrs) > 0 {
hdr := records[0].Header()
rrset := &route53.ResourceRecordSet{
Type: aws.String(dns.Type(hdr.Rrtype).String()),
Name: aws.String(hdr.Name),
ResourceRecords: rrs,
TTL: aws.Int64(int64(hdr.Ttl)),
}
if awsrr, ok := records[0].(*AWSRR); ok {
switch route := awsrr.Route.(type) {
case *FailoverRoute:
rrset.Failover = aws.String(route.Failover)
case *GeoLocationRoute:
rrset.GeoLocation = &route53.GeoLocation{
CountryCode: route.CountryCode,
ContinentCode: route.ContinentCode,
SubdivisionCode: route.SubdivisionCode,
}
case *LatencyRoute:
rrset.Region = aws.String(route.Region)
case *WeightedRoute:
rrset.Weight = aws.Int64(route.Weight)
}
if awsrr.HealthCheckId != nil {
rrset.HealthCheckId = awsrr.HealthCheckId
}
rrset.SetIdentifier = aws.String(awsrr.Identifier)
}
return rrset
}
return nil
}
// Report is a plain reporting function that the server can use for REFUSED and other
// queries that are turned down because they don't match any middleware.
func Report(state middleware.State, zone, rcode string, size int, start time.Time) {
if requestCount == nil {
// no metrics are enabled
return
}
// Proto and Family
net := state.Proto()
fam := "1"
if state.Family() == 2 {
fam = "2"
}
typ := state.QType()
requestCount.WithLabelValues(zone, net, fam).Inc()
requestDuration.WithLabelValues(zone).Observe(float64(time.Since(start) / time.Millisecond))
if state.Do() {
requestDo.WithLabelValues(zone).Inc()
}
if _, known := monitorType[typ]; known {
requestType.WithLabelValues(zone, dns.Type(typ).String()).Inc()
} else {
requestType.WithLabelValues(zone, other).Inc()
}
if typ == dns.TypeIXFR || typ == dns.TypeAXFR {
responseTransferSize.WithLabelValues(zone, net).Observe(float64(size))
requestTransferSize.WithLabelValues(zone, net).Observe(float64(state.Size()))
} else {
responseSize.WithLabelValues(zone, net).Observe(float64(size))
requestSize.WithLabelValues(zone, net).Observe(float64(state.Size()))
}
responseRcode.WithLabelValues(zone, rcode).Inc()
}
func TestDNSResponse(t *testing.T) {
const TestAddr = "127.0.0.1:9953"
config := NewConfig()
config.dnsAddr = TestAddr
server := NewDNSServer(config)
go server.Start()
// Allow some time for server to start
time.Sleep(250 * time.Millisecond)
server.AddService("foo", Service{Name: "foo", Image: "bar", Ip: net.ParseIP("127.0.0.1")})
server.AddService("baz", Service{Name: "baz", Image: "bar", Ip: net.ParseIP("127.0.0.1"), Ttl: -1})
server.AddService("biz", Service{Name: "hey", Image: "", Ip: net.ParseIP("127.0.0.4")})
server.AddService("joe", Service{Name: "joe", Image: "", Ip: net.ParseIP("127.0.0.5"), Aliases: []string{"lala.docker", "super-alias", "alias.domain"}})
var inputs = []struct {
query string
expected int
qType string
rcode int
}{
{"google.com.", -1, "A", dns.RcodeSuccess},
{"google.com.", -1, "MX", 0},
{"google.com.", -1, "AAAA", 0}, // google has AAAA records
{"docker.", 5, "A", 0},
{"docker.", 5, "MX", 0},
{"*.docker.", 5, "A", 0},
{"*.docker.", 5, "MX", 0},
{"bar.docker.", 2, "A", 0},
{"bar.docker.", 2, "MX", 0},
{"bar.docker.", 0, "AAAA", 0},
{"foo.docker.", 0, "A", dns.RcodeNameError},
{"foo.docker.", 0, "MX", dns.RcodeNameError},
{"baz.bar.docker.", 1, "A", 0},
{"baz.bar.docker.", 1, "MX", 0},
{"joe.docker.", 1, "A", 0},
{"joe.docker.", 1, "MX", 0},
{"joe.docker.", 0, "AAAA", 0},
{"super-alias.", 1, "A", 0},
{"super-alias.", 1, "MX", 0},
{"alias.domain.", 1, "A", 0},
{"alias.domain.", 1, "MX", 0},
{"1.0.0.127.in-addr.arpa.", 4, "PTR", 0}, // two services match with two domains each
{"5.0.0.127.in-addr.arpa.", 4, "PTR", 0}, // one service match with three aliases
{"4.0.0.127.in-addr.arpa.", 1, "PTR", 0}, // only one service with a single domain
{"2.0.0.127.in-addr.arpa.", 0, "PTR", dns.RcodeNameError}, // no match
}
c := new(dns.Client)
for _, input := range inputs {
t.Log("Query", input.query, input.qType)
qType := dns.StringToType[input.qType]
m := new(dns.Msg)
m.SetQuestion(input.query, qType)
r, _, err := c.Exchange(m, TestAddr)
if err != nil {
t.Error("Error response from the server", err)
break
}
if len(r.Answer) == 0 {
if _, ok := r.Ns[0].(*dns.SOA); !ok {
t.Error(input, "No SOA answer")
}
}
if input.expected > 0 && len(r.Answer) != input.expected {
t.Error(input, "Expected:", input.expected,
" Got:", len(r.Answer))
}
if input.expected < 0 && len(r.Answer) == 0 {
t.Error(input, "Expected at least one record but got none")
}
if r.Rcode != input.rcode {
t.Error(input, "Rcode expected:",
dns.RcodeToString[input.rcode],
" got:", dns.RcodeToString[r.Rcode])
}
for _, a := range r.Answer {
rrType := dns.Type(a.Header().Rrtype).String()
if input.qType != rrType {
t.Error("Did not receive ", input.qType, " resource record")
} else {
t.Log("Received expected response RR type", rrType, "code", dns.RcodeToString[input.rcode])
}
}
}
}
func route(w dns.ResponseWriter, req *dns.Msg) {
clientIp, _, _ := net.SplitHostPort(w.RemoteAddr().String())
// One question at a time please
if len(req.Question) != 1 {
dns.HandleFailed(w, req)
log.WithFields(log.Fields{"client": clientIp}).Warn("Rejected multi-question query")
return
}
question := req.Question[0]
rrString := dns.Type(question.Qtype).String()
// We are assuming the JSON config has all names as lower case
fqdn := strings.ToLower(question.Name)
// Internets only
if question.Qclass != dns.ClassINET {
m := new(dns.Msg)
m.SetReply(req)
m.Authoritative = false
m.RecursionDesired = false
m.RecursionAvailable = false
m.Rcode = dns.RcodeNotImplemented
w.WriteMsg(m)
log.WithFields(log.Fields{"question": fqdn, "type": rrString, "client": clientIp}).Warn("Rejected non-inet query")
return
}
// ANY queries are bad, mmmkay...
if question.Qtype == dns.TypeANY {
m := new(dns.Msg)
m.SetReply(req)
m.Authoritative = false
m.RecursionDesired = false
m.RecursionAvailable = false
m.Rcode = dns.RcodeNotImplemented
w.WriteMsg(m)
log.WithFields(log.Fields{"question": fqdn, "type": rrString, "client": clientIp}).Warn("Rejected ANY query")
return
}
proto := "UDP"
if isTcp(w) {
proto = "TCP"
}
log.WithFields(log.Fields{"question": fqdn, "type": rrString, "client": clientIp, "proto": proto}).Debug("Request")
// A records may return CNAME answer(s) plus A answer(s)
if question.Qtype == dns.TypeA {
found, ok := answers.Addresses(clientIp, fqdn, nil, 1)
if ok && len(found) > 0 {
log.WithFields(log.Fields{"client": clientIp, "type": rrString, "question": fqdn, "answers": len(found)}).Info("Answered locally")
Respond(w, req, found)
return
}
} else {
// Specific request for another kind of record
keys := []string{clientIp, DEFAULT_KEY}
for _, key := range keys {
// Client-specific answers
found, ok := answers.Matching(question.Qtype, key, fqdn)
if ok {
log.WithFields(log.Fields{"client": key, "type": rrString, "question": fqdn, "answers": len(found)}).Info("Answered from config for ", key)
Respond(w, req, found)
return
}
}
log.Debug("No match found in config")
}
// Phone a friend
msg, err := ResolveTryAll(fqdn, question.Qtype, answers.Recursers(clientIp))
if err == nil {
msg.SetReply(req)
w.WriteMsg(msg)
log.WithFields(log.Fields{"client": clientIp, "type": rrString, "question": fqdn}).Info("Sent recursive response")
return
}
// I give up
log.WithFields(log.Fields{"client": clientIp, "type": rrString, "question": fqdn}).Warn("No answer found")
dns.HandleFailed(w, req)
}
func rrHeaderFmt(hdr dns.RR_Header) string {
return fmt.Sprintf("'%s' %s ttl: %d", hdr.Name, dns.Type(hdr.Rrtype).String(), hdr.Ttl)
}
func route(w dns.ResponseWriter, req *dns.Msg) {
// Setup reply
m := new(dns.Msg)
m.SetReply(req)
m.Authoritative = true
m.RecursionAvailable = true
m.Compress = true
clientIp, _, _ := net.SplitHostPort(w.RemoteAddr().String())
// One question at a time please
if len(req.Question) != 1 {
dns.HandleFailed(w, req)
log.WithFields(log.Fields{"client": clientIp}).Warn("Rejected multi-question query")
return
}
question := req.Question[0]
rrString := dns.Type(question.Qtype).String()
// We are assuming the config has all names as lower case
fqdn := strings.ToLower(question.Name)
// Internets only
if question.Qclass != dns.ClassINET {
m.Authoritative = false
m.RecursionDesired = false
m.RecursionAvailable = false
m.Rcode = dns.RcodeNotImplemented
w.WriteMsg(m)
log.WithFields(log.Fields{"question": fqdn, "type": rrString, "client": clientIp}).Warn("Rejected non-inet query")
return
}
// ANY queries are bad, mmmkay...
if question.Qtype == dns.TypeANY {
m.Authoritative = false
m.RecursionDesired = false
m.RecursionAvailable = false
m.Rcode = dns.RcodeNotImplemented
w.WriteMsg(m)
log.WithFields(log.Fields{"question": fqdn, "type": rrString, "client": clientIp}).Warn("Rejected ANY query")
return
}
proto := "UDP"
if isTcp(w) {
proto = "TCP"
}
log.WithFields(log.Fields{"question": fqdn, "type": rrString, "client": clientIp, "proto": proto}).Debug("Request")
if msg := clientSpecificCacheHit(clientIp, req); msg != nil {
Respond(w, req, msg)
log.WithFields(log.Fields{"client": clientIp, "type": rrString, "question": fqdn}).Debug("Sent client-specific cached response")
return
}
if msg := globalCacheHit(req); msg != nil {
Respond(w, req, msg)
log.WithFields(log.Fields{"client": clientIp, "type": rrString, "question": fqdn}).Debug("Sent globally cached response")
return
}
// A records may return CNAME answer(s) plus A answer(s)
if question.Qtype == dns.TypeA {
found, ok := answers.Addresses(clientIp, fqdn, nil, 1)
if ok && len(found) > 0 {
log.WithFields(log.Fields{"client": clientIp, "type": rrString, "question": fqdn, "answers": len(found)}).Debug("Answered locally")
m.Answer = found
addToClientSpecificCache(clientIp, req, m)
Respond(w, req, m)
return
}
} else {
// Specific request for another kind of record
keys := []string{clientIp, DEFAULT_KEY}
for _, key := range keys {
// Client-specific answers
found, ok := answers.Matching(question.Qtype, key, fqdn)
if ok {
log.WithFields(log.Fields{"client": key, "type": rrString, "question": fqdn, "answers": len(found)}).Debug("Answered from config for ", key)
m.Answer = found
addToClientSpecificCache(clientIp, req, m)
Respond(w, req, m)
return
}
}
log.Debug("No match found in config")
}
// If we are authoritative for a suffix the label has, there's no point trying the recursive DNS
authoritativeFor := answers.AuthoritativeSuffixes()
for _, suffix := range authoritativeFor {
if strings.HasSuffix(fqdn, suffix) {
log.WithFields(log.Fields{"client": clientIp, "type": rrString, "question": fqdn}).Debugf("Not answered locally, but I am authoritative for %s", suffix)
m.Authoritative = true
m.RecursionAvailable = false
me := strings.TrimLeft(suffix, ".")
hdr := dns.RR_Header{Name: me, Rrtype: dns.TypeSOA, Class: dns.ClassINET, Ttl: uint32(*defaultTtl)}
serial++
record := &dns.SOA{Hdr: hdr, Ns: me, Mbox: me, Serial: serial, Refresh: 60, Retry: 10, Expire: 86400, Minttl: 1}
m.Ns = append(m.Ns, record)
Respond(w, req, m)
return
}
}
// Phone a friend - Forward original query
msg, err := ResolveTryAll(req, answers.Recursers(clientIp))
if err == nil {
msg.Compress = true
msg.Id = req.Id
// We don't support AAAA, but an NXDOMAIN from the recursive resolver
// doesn't necessarily mean there are never any records for that domain,
// so rewrite the response code to NOERROR.
if (question.Qtype == dns.TypeAAAA) && (msg.Rcode == dns.RcodeNameError) {
log.WithFields(log.Fields{"client": clientIp, "type": rrString, "question": fqdn}).Debug("Rewrote AAAA NXDOMAIN to NOERROR")
msg.Rcode = dns.RcodeSuccess
}
addToGlobalCache(req, msg)
Respond(w, req, msg)
log.WithFields(log.Fields{"client": clientIp, "type": rrString, "question": fqdn}).Debug("Sent recursive response")
return
}
// I give up
log.WithFields(log.Fields{"client": clientIp, "type": rrString, "question": fqdn}).Info("No answer found")
dns.HandleFailed(w, req)
}
func textConvertMessage(m *Message, s *bytes.Buffer) {
isQuery := false
printQueryAddress := false
switch *m.Type {
case Message_CLIENT_QUERY,
Message_RESOLVER_QUERY,
Message_AUTH_QUERY,
Message_FORWARDER_QUERY,
Message_TOOL_QUERY:
isQuery = true
case Message_CLIENT_RESPONSE,
Message_RESOLVER_RESPONSE,
Message_AUTH_RESPONSE,
Message_FORWARDER_RESPONSE,
Message_TOOL_RESPONSE:
isQuery = false
default:
s.WriteString("[unhandled Message.Type]\n")
return
}
if isQuery {
textConvertTime(s, m.QueryTimeSec, m.QueryTimeNsec)
} else {
textConvertTime(s, m.ResponseTimeSec, m.ResponseTimeNsec)
}
s.WriteString(" ")
switch *m.Type {
case Message_CLIENT_QUERY,
Message_CLIENT_RESPONSE:
{
s.WriteString("C")
}
case Message_RESOLVER_QUERY,
Message_RESOLVER_RESPONSE:
{
s.WriteString("R")
}
case Message_AUTH_QUERY,
Message_AUTH_RESPONSE:
{
s.WriteString("A")
}
case Message_FORWARDER_QUERY,
Message_FORWARDER_RESPONSE:
{
s.WriteString("F")
}
case Message_STUB_QUERY,
Message_STUB_RESPONSE:
{
s.WriteString("S")
}
case Message_TOOL_QUERY,
Message_TOOL_RESPONSE:
{
s.WriteString("T")
}
}
if isQuery {
s.WriteString("Q ")
} else {
s.WriteString("R ")
}
switch *m.Type {
case Message_CLIENT_QUERY,
Message_CLIENT_RESPONSE,
Message_AUTH_QUERY,
Message_AUTH_RESPONSE:
printQueryAddress = true
}
if printQueryAddress {
textConvertIP(s, m.QueryAddress)
} else {
textConvertIP(s, m.ResponseAddress)
}
s.WriteString(" ")
if m.SocketProtocol != nil {
s.WriteString(m.SocketProtocol.String())
}
s.WriteString(" ")
var err error
msg := new(dns.Msg)
if isQuery {
s.WriteString(strconv.Itoa(len(m.QueryMessage)))
s.WriteString("b ")
err = msg.Unpack(m.QueryMessage)
} else {
s.WriteString(strconv.Itoa(len(m.ResponseMessage)))
s.WriteString("b ")
err = msg.Unpack(m.ResponseMessage)
}
if err != nil {
s.WriteString("X ")
} else {
s.WriteString("\"" + msg.Question[0].Name + "\" ")
s.WriteString(dns.Class(msg.Question[0].Qclass).String() + " ")
s.WriteString(dns.Type(msg.Question[0].Qtype).String())
}
s.WriteString("\n")
}
// Type returns the type of the question as a string.
func (s *State) Type() string { return dns.Type(s.Req.Question[0].Qtype).String() }
func answerQuestion(cfg *Config, c dnscache.Context, q *dns.Question, defaultTTL, qDepth uint32) []dns.RR {
if c.Event == dnscache.Renewal && qDepth == 0 {
log.Printf("DNS Renewal %s %s\n", q.Name, dns.Type(q.Qtype).String())
} else {
log.Printf(" [%9.04fms] %-7s %s %s\n", msElapsed(c.Start, time.Now()), strings.ToUpper(c.Event.String()), q.Name, dns.Type(q.Qtype).String())
}
answerTTL := defaultTTL
var answers []dns.RR
var secondaryAnswers []dns.RR
var wouldLikeForwarder = true
entry, rrType, err := fetchBestEntry(cfg, q)
if err == nil {
wouldLikeForwarder = false
if entry.TTL > 0 {
answerTTL = entry.TTL
}
log.Printf(" [%9.04fms] FOUND %s %s\n", msElapsed(c.Start, time.Now()), q.Name, dns.Type(rrType).String())
switch q.Qtype {
case dns.TypeSOA:
answer := answerSOA(q, entry)
answers = append(answers, answer)
default:
// ... for answers that have values
for i := range entry.Values {
value := &entry.Values[i]
if value.Expiration != nil {
expiration := value.Expiration.Unix()
now := time.Now().Unix()
if expiration < now {
//log.Printf("[Lookup [%s] [%s] (is expired)]\n", q.Name, qType)
continue
}
remaining := uint32(expiration - now)
if remaining < answerTTL {
answerTTL = remaining
log.Printf(" [%9.04fms] EXPIRES %d\n", msElapsed(c.Start, time.Now()), remaining)
}
}
if value.TTL > 0 && value.TTL < answerTTL {
answerTTL = value.TTL
}
switch rrType {
// FIXME: Add more RR types!
// http://godoc.org/github.com/miekg/dns has info as well as
// http://en.wikipedia.org/wiki/List_of_DNS_record_types
case dns.TypeTXT:
answer := answerTXT(q, value)
answers = append(answers, answer)
case dns.TypeA:
answer := answerA(q, value)
answers = append(answers, answer)
case dns.TypeAAAA:
answer := answerAAAA(q, value)
answers = append(answers, answer)
case dns.TypeNS:
answer := answerNS(q, value)
answers = append(answers, answer)
case dns.TypeCNAME:
answer, target := answerCNAME(q, value)
answers = append(answers, answer)
q2 := q
q2.Name = target // replace question's name with new name
secondaryAnswers = append(secondaryAnswers, answerQuestion(cfg, c, q2, defaultTTL, qDepth+1)...)
case dns.TypeDNAME:
answer := answerDNAME(q, value)
answers = append(answers, answer)
wouldLikeForwarder = true
case dns.TypePTR:
answer := answerPTR(q, value)
answers = append(answers, answer)
case dns.TypeMX:
answer := answerMX(q, value)
// FIXME: are we supposed to be returning these in prio ordering?
// ... or maybe it does that for us? or maybe it's the enduser's problem?
answers = append(answers, answer)
case dns.TypeSRV:
answer := answerSRV(q, value)
// FIXME: are we supposed to be returning these rando-weighted and in priority ordering?
// ... or maybe it does that for us? or maybe it's the enduser's problem?
answers = append(answers, answer)
case dns.TypeSSHFP:
// TODO: implement SSHFP
// http://godoc.org/github.com/miekg/dns#SSHFP
// NOTE: we must implement DNSSEC before using this RR type
}
}
}
}
for _, answer := range answers {
answer.Header().Ttl = answerTTL // FIXME: I think this might be inappropriate
//log.Printf("[APPLIED TTL [%s] [%s] %d]\n", q.Name, dns.Type(q.Qtype).String(), answerTTL)
}
// Append the results of secondary queries, such as the results of CNAME and DNAME records
answers = append(answers, secondaryAnswers...)
// check to see if we host this zone; if yes, don't allow use of ext forwarders
// ... also, check to see if we hit a DNAME so we can handle that aliasing
// FIXME: Only forward if we are configured as a forwarder
if wouldLikeForwarder && !haveAuthority(cfg, q) {
log.Printf(" [%9.04fms] FORWARD %s %s\n", msElapsed(c.Start, time.Now()), q.Name, dns.Type(q.Qtype).String())
answers = append(answers, forwardQuestion(q, cfg.DNSForwarders())...)
}
return answers
}
// ServeDNS is the entry point for every request to the address that s
// is bound to. It acts as a multiplexer for the requests zonename as
// defined in the request so that the correct zone
// (configuration and middleware stack) will handle the request.
func (s *Server) ServeDNS(w dns.ResponseWriter, r *dns.Msg) {
defer func() {
// In case the user doesn't enable error middleware, we still
// need to make sure that we stay alive up here
if rec := recover(); rec != nil {
DefaultErrorFunc(w, r, dns.RcodeServerFailure)
}
}()
if m, err := middleware.Edns0Version(r); err != nil { // Wrong EDNS version, return at once.
rc := middleware.RcodeToString(dns.RcodeBadVers)
state := middleware.State{W: w, Req: r}
metrics.Report(state, metrics.Dropped, rc, m.Len(), time.Now())
w.WriteMsg(m)
return
}
// Execute the optional request callback if it exists
if s.ReqCallback != nil && s.ReqCallback(w, r) {
return
}
q := r.Question[0].Name
b := make([]byte, len(q))
off, end := 0, false
ctx := context.Background()
for {
l := len(q[off:])
for i := 0; i < l; i++ {
b[i] = q[off+i]
// normalize the name for the lookup
if b[i] >= 'A' && b[i] <= 'Z' {
b[i] |= ('a' - 'A')
}
}
if h, ok := s.zones[string(b[:l])]; ok {
if r.Question[0].Qtype != dns.TypeDS {
rcode, _ := h.stack.ServeDNS(ctx, w, r)
if RcodeNoClientWrite(rcode) {
DefaultErrorFunc(w, r, rcode)
}
return
}
}
off, end = dns.NextLabel(q, off)
if end {
break
}
}
// Wildcard match, if we have found nothing try the root zone as a last resort.
if h, ok := s.zones["."]; ok {
rcode, _ := h.stack.ServeDNS(ctx, w, r)
if RcodeNoClientWrite(rcode) {
DefaultErrorFunc(w, r, rcode)
}
return
}
// Still here? Error out with REFUSED and some logging
remoteHost := w.RemoteAddr().String()
DefaultErrorFunc(w, r, dns.RcodeRefused)
log.Printf("[INFO] \"%s %s %s\" - No such zone at %s (Remote: %s)", dns.Type(r.Question[0].Qtype), dns.Class(r.Question[0].Qclass), q, s.Addr, remoteHost)
}
func main() {
bytes, err := ioutil.ReadFile(*zoneFile)
if err != nil {
log.Panic(err)
}
zone := string(bytes)
reader := strings.NewReader(zone)
records := make(map[RecordKey]*TerraformRecord)
for rr := range dns.ParseZone(reader, *domain, *zoneFile) {
if rr.Error != nil {
log.Printf("Error: %v\n", rr.Error)
} else {
header := rr.Header()
recordType := dns.Type(header.Rrtype).String()
isExcluded, ok := excludedTypes[recordType]
if ok && isExcluded {
continue
}
name := strings.ToLower(header.Name)
data := strings.TrimPrefix(rr.String(), header.String())
if recordType == "CNAME" {
data = strings.ToLower(data)
}
key := RecordKey{
Name: name,
Type: recordType,
}
if rec, ok := records[key]; ok {
rec.Data = append(rec.Data, data)
if rr.Comment != "" {
rec.Comments = append(rec.Comments, strings.TrimLeft(rr.Comment, ";"))
}
} else {
comments := make([]string, 0)
if rr.Comment != "" {
comments = append(comments, strings.TrimLeft(rr.Comment, ";"))
}
records[key] = &TerraformRecord{
Name: key.Name,
Type: key.Type,
Ttl: header.Ttl,
Data: []string{data},
Comments: comments,
}
}
}
}
zoneName := strings.TrimRight(*domain, ".")
ZoneTemplateData := ZoneTemplateData{
Id: strings.Replace(zoneName, ".", "-", -1),
Domain: zoneName,
}
terraformZone := template.Must(template.New("zone").Parse(zoneTemplate))
terraformZone.Execute(os.Stdout, ZoneTemplateData)
resource := template.Must(template.New("resource").Funcs(template.FuncMap{"ensureQuoted": ensureQuoted}).Parse(recordTemplate))
recordKeys := make(RecordKeySlice, 0, len(records))
for key, _ := range records {
recordKeys = append(recordKeys, key)
}
sort.Sort(sort.Reverse(recordKeys))
for _, key := range recordKeys {
rec := records[key]
hyphenatedName := strings.Replace(strings.TrimRight(rec.Name, "."), ".", "-", -1)
wildcardCleanedName := strings.Replace(hyphenatedName, "*", "wildcard", -1)
id := fmt.Sprintf("%s-%s", wildcardCleanedName, rec.Type)
info := RecordTemplateData{
ResourceId: id,
Record: rec,
Zone: ZoneTemplateData,
}
resource.Execute(os.Stdout, info)
}
}
func (h ErrorHandler) recovery(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) {
rec := recover()
if rec == nil {
return
}
state := middleware.State{W: w, Req: r}
// Obtain source of panic
// From: https://gist.github.com/swdunlop/9629168
var name, file string // function name, file name
var line int
var pc [16]uintptr
n := runtime.Callers(3, pc[:])
for _, pc := range pc[:n] {
fn := runtime.FuncForPC(pc)
if fn == nil {
continue
}
file, line = fn.FileLine(pc)
name = fn.Name()
if !strings.HasPrefix(name, "runtime.") {
break
}
}
// Trim file path
delim := "/coredns/"
pkgPathPos := strings.Index(file, delim)
if pkgPathPos > -1 && len(file) > pkgPathPos+len(delim) {
file = file[pkgPathPos+len(delim):]
}
panicMsg := fmt.Sprintf("%s [PANIC %s %s] %s:%d - %v", time.Now().Format(timeFormat), r.Question[0].Name, dns.Type(r.Question[0].Qtype), file, line, rec)
if h.Debug {
// Write error and stack trace to the response rather than to a log
var stackBuf [4096]byte
stack := stackBuf[:runtime.Stack(stackBuf[:], false)]
answer := debugMsg(dns.RcodeServerFailure, r)
// add stack buf in TXT, limited to 255 chars for now.
txt, _ := dns.NewRR(". IN 0 TXT " + string(stack[:255]))
answer.Answer = append(answer.Answer, txt)
state.SizeAndDo(answer)
w.WriteMsg(answer)
} else {
// Currently we don't use the function name, since file:line is more conventional
h.Log.Printf(panicMsg)
}
}
func questionToString(q dns.Question) string {
return fmt.Sprintf("%s %s %s", q.Name, dns.Class(q.Qclass), dns.Type(q.Qtype))
}