func TestDNS_CaseInsensitiveNodeLookup(t *testing.T) {
dir, srv := makeDNSServer(t)
defer os.RemoveAll(dir)
defer srv.agent.Shutdown()
testutil.WaitForLeader(t, srv.agent.RPC, "dc1")
// Register node
args := &structs.RegisterRequest{
Datacenter: "dc1",
Node: "Foo",
Address: "127.0.0.1",
}
var out struct{}
if err := srv.agent.RPC("Catalog.Register", args, &out); err != nil {
t.Fatalf("err: %v", err)
}
m := new(dns.Msg)
m.SetQuestion("fOO.node.dc1.consul.", dns.TypeANY)
c := new(dns.Client)
addr, _ := srv.agent.config.ClientListener("", srv.agent.config.Ports.DNS)
in, _, err := c.Exchange(m, addr.String())
if err != nil {
t.Fatalf("err: %v", err)
}
if len(in.Answer) != 1 {
t.Fatalf("empty lookup: %#v", in)
}
}
func TestDNS_ServiceLookup_TagPeriod(t *testing.T) {
dir, srv := makeDNSServer(t)
defer os.RemoveAll(dir)
defer srv.agent.Shutdown()
testutil.WaitForLeader(t, srv.agent.RPC, "dc1")
// Register node
args := &structs.RegisterRequest{
Datacenter: "dc1",
Node: "foo",
Address: "127.0.0.1",
Service: &structs.NodeService{
Service: "db",
Tags: []string{"v1.master"},
Port: 12345,
},
}
var out struct{}
if err := srv.agent.RPC("Catalog.Register", args, &out); err != nil {
t.Fatalf("err: %v", err)
}
m := new(dns.Msg)
m.SetQuestion("v1.master.db.service.consul.", dns.TypeSRV)
c := new(dns.Client)
addr, _ := srv.agent.config.ClientListener("", srv.agent.config.Ports.DNS)
in, _, err := c.Exchange(m, addr.String())
if err != nil {
t.Fatalf("err: %v", err)
}
if len(in.Answer) != 1 {
t.Fatalf("Bad: %#v", in)
}
srvRec, ok := in.Answer[0].(*dns.SRV)
if !ok {
t.Fatalf("Bad: %#v", in.Answer[0])
}
if srvRec.Port != 12345 {
t.Fatalf("Bad: %#v", srvRec)
}
if srvRec.Target != "foo.node.dc1.consul." {
t.Fatalf("Bad: %#v", srvRec)
}
aRec, ok := in.Extra[0].(*dns.A)
if !ok {
t.Fatalf("Bad: %#v", in.Extra[0])
}
if aRec.Hdr.Name != "foo.node.dc1.consul." {
t.Fatalf("Bad: %#v", in.Extra[0])
}
if aRec.A.String() != "127.0.0.1" {
t.Fatalf("Bad: %#v", in.Extra[0])
}
}
func TestDNS_IsAlive(t *testing.T) {
dir, srv := makeDNSServer(t)
defer os.RemoveAll(dir)
defer srv.agent.Shutdown()
m := new(dns.Msg)
m.SetQuestion("_test.consul.", dns.TypeANY)
c := new(dns.Client)
addr, _ := srv.agent.config.ClientListener("", srv.agent.config.Ports.DNS)
in, _, err := c.Exchange(m, addr.String())
if err != nil {
t.Fatalf("err: %v", err)
}
if len(in.Answer) != 1 {
t.Fatalf("Bad: %#v", in)
}
txt, ok := in.Answer[0].(*dns.TXT)
if !ok {
t.Fatalf("Bad: %#v", in.Answer[0])
}
if txt.Txt[0] != "ok" {
t.Fatalf("Bad: %#v", in.Answer[0])
}
}
func (s *server) unregister() error {
resp := new(dns.Msg)
resp.Answer = []dns.RR{}
resp.Extra = []dns.RR{}
s.composeLookupAnswers(resp, 0)
return s.multicastResponse(resp)
}
func ExamplePrivateHandle() {
dns.PrivateHandle("APAIR", TypeAPAIR, NewAPAIR)
defer dns.PrivateHandleRemove(TypeAPAIR)
rr, err := dns.NewRR("miek.nl. APAIR (1.2.3.4 1.2.3.5)")
if err != nil {
log.Fatal("could not parse APAIR record: ", err)
}
fmt.Println(rr)
// Output: miek.nl. 3600 IN APAIR 1.2.3.4 1.2.3.5
m := new(dns.Msg)
m.Id = 12345
m.SetQuestion("miek.nl.", TypeAPAIR)
m.Answer = append(m.Answer, rr)
fmt.Println(m)
// ;; opcode: QUERY, status: NOERROR, id: 12345
// ;; flags: rd; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
//
// ;; QUESTION SECTION:
// ;miek.nl. IN APAIR
//
// ;; ANSWER SECTION:
// miek.nl. 3600 IN APAIR 1.2.3.4 1.2.3.5
}
func (s *server) composeBrowsingAnswers(resp *dns.Msg, ttl uint32) {
ptr := &dns.PTR{
Hdr: dns.RR_Header{
Name: s.service.ServiceName(),
Rrtype: dns.TypePTR,
Class: dns.ClassINET,
Ttl: ttl,
},
Ptr: s.service.ServiceInstanceName(),
}
resp.Answer = append(resp.Answer, ptr)
txt := &dns.TXT{
Hdr: dns.RR_Header{
Name: s.service.ServiceInstanceName(),
Rrtype: dns.TypeTXT,
Class: dns.ClassINET,
Ttl: ttl,
},
Txt: s.service.Text,
}
srv := &dns.SRV{
Hdr: dns.RR_Header{
Name: s.service.ServiceInstanceName(),
Rrtype: dns.TypeSRV,
Class: dns.ClassINET,
Ttl: ttl,
},
Priority: 0,
Weight: 0,
Port: uint16(s.service.Port),
Target: s.service.HostName,
}
resp.Extra = append(resp.Extra, srv, txt)
if s.service.AddrIPv4 != nil {
a := &dns.A{
Hdr: dns.RR_Header{
Name: s.service.HostName,
Rrtype: dns.TypeA,
Class: dns.ClassINET,
Ttl: ttl,
},
A: s.service.AddrIPv4,
}
resp.Extra = append(resp.Extra, a)
}
if s.service.AddrIPv6 != nil {
aaaa := &dns.AAAA{
Hdr: dns.RR_Header{
Name: s.service.HostName,
Rrtype: dns.TypeAAAA,
Class: dns.ClassINET,
Ttl: ttl,
},
AAAA: s.service.AddrIPv6,
}
resp.Extra = append(resp.Extra, aaaa)
}
}
// resolveCNAME is used to recursively resolve CNAME records
func (d *DNSServer) resolveCNAME(name string) []dns.RR {
// Do nothing if we don't have a recursor
if len(d.recursors) == 0 {
return nil
}
// Ask for any A records
m := new(dns.Msg)
m.SetQuestion(name, dns.TypeA)
// Make a DNS lookup request
c := &dns.Client{Net: "udp"}
var r *dns.Msg
var rtt time.Duration
var err error
for _, recursor := range d.recursors {
r, rtt, err = c.Exchange(m, recursor)
if err == nil {
d.logger.Printf("[DEBUG] dns: cname recurse RTT for %v (%v)", name, rtt)
return r.Answer
}
d.logger.Printf("[ERR] dns: cname recurse failed for %v: %v", name, err)
}
d.logger.Printf("[ERR] dns: all resolvers failed for %v", name)
return nil
}
// parsePacket is used to parse an incoming packet
func (s *server) parsePacket(packet []byte, from net.Addr) error {
var msg dns.Msg
if err := msg.Unpack(packet); err != nil {
log.Printf("[ERR] bonjour: Failed to unpack packet: %v", err)
return err
}
return s.handleQuery(&msg, from)
}
func TestDNS_ServiceLookup_CNAME(t *testing.T) {
dir, srv := makeDNSServer(t)
defer os.RemoveAll(dir)
defer srv.agent.Shutdown()
testutil.WaitForLeader(t, srv.agent.RPC, "dc1")
// Register node
args := &structs.RegisterRequest{
Datacenter: "dc1",
Node: "google",
Address: "www.google.com",
Service: &structs.NodeService{
Service: "search",
Port: 80,
},
}
var out struct{}
if err := srv.agent.RPC("Catalog.Register", args, &out); err != nil {
t.Fatalf("err: %v", err)
}
m := new(dns.Msg)
m.SetQuestion("search.service.consul.", dns.TypeANY)
c := new(dns.Client)
addr, _ := srv.agent.config.ClientListener("", srv.agent.config.Ports.DNS)
in, _, err := c.Exchange(m, addr.String())
if err != nil {
t.Fatalf("err: %v", err)
}
if len(in.Answer) != 4 {
t.Fatalf("Bad: %#v", in)
}
// Should have google CNAME
cnRec, ok := in.Answer[0].(*dns.CNAME)
if !ok {
t.Fatalf("Bad: %#v", in.Answer[0])
}
if cnRec.Target != "www.google.com." {
t.Fatalf("Bad: %#v", in.Answer[0])
}
// Check we recursively resolve
for i := 1; i < 4; i++ {
if _, ok := in.Answer[i].(*dns.A); !ok {
t.Fatalf("Bad: %#v", in.Answer[i])
}
}
}
// Pack the dns.Msg and write to available connections (multicast)
func (c *client) sendQuery(msg *dns.Msg) error {
buf, err := msg.Pack()
if err != nil {
return err
}
if c.ipv4conn != nil {
c.ipv4conn.WriteTo(buf, ipv4Addr)
}
if c.ipv4conn != nil {
c.ipv4conn.WriteTo(buf, ipv6Addr)
}
return nil
}
// multicastResponse us used to send a multicast response packet
func (c *server) multicastResponse(msg *dns.Msg) error {
buf, err := msg.Pack()
if err != nil {
log.Println("Failed to pack message!")
return err
}
if c.ipv4conn != nil {
c.ipv4conn.WriteTo(buf, ipv4Addr)
}
if c.ipv6conn != nil {
c.ipv6conn.WriteTo(buf, ipv6Addr)
}
return nil
}
// sendResponse is used to send a unicast response packet
func (s *server) sendResponse(resp *dns.Msg, from net.Addr) error {
buf, err := resp.Pack()
if err != nil {
return err
}
addr := from.(*net.UDPAddr)
if addr.IP.To4() != nil {
_, err = s.ipv4conn.WriteToUDP(buf, addr)
return err
} else {
_, err = s.ipv6conn.WriteToUDP(buf, addr)
return err
}
}
func TestDNS_NodeLookup_CNAME(t *testing.T) {
dir, srv := makeDNSServer(t)
defer os.RemoveAll(dir)
defer srv.agent.Shutdown()
testutil.WaitForLeader(t, srv.agent.RPC, "dc1")
// Register node
args := &structs.RegisterRequest{
Datacenter: "dc1",
Node: "google",
Address: "www.google.com",
}
var out struct{}
if err := srv.agent.RPC("Catalog.Register", args, &out); err != nil {
t.Fatalf("err: %v", err)
}
m := new(dns.Msg)
m.SetQuestion("google.node.consul.", dns.TypeANY)
c := new(dns.Client)
addr, _ := srv.agent.config.ClientListener("", srv.agent.config.Ports.DNS)
in, _, err := c.Exchange(m, addr.String())
if err != nil {
t.Fatalf("err: %v", err)
}
// Should have the CNAME record + a few A records
if len(in.Answer) < 2 {
t.Fatalf("Bad: %#v", in)
}
cnRec, ok := in.Answer[0].(*dns.CNAME)
if !ok {
t.Fatalf("Bad: %#v", in.Answer[0])
}
if cnRec.Target != "www.google.com." {
t.Fatalf("Bad: %#v", in.Answer[0])
}
if cnRec.Hdr.Ttl != 0 {
t.Fatalf("Bad: %#v", in.Answer[0])
}
}
func TestDNS_NodeLookup_AAAA(t *testing.T) {
dir, srv := makeDNSServer(t)
defer os.RemoveAll(dir)
defer srv.agent.Shutdown()
testutil.WaitForLeader(t, srv.agent.RPC, "dc1")
// Register node
args := &structs.RegisterRequest{
Datacenter: "dc1",
Node: "bar",
Address: "::4242:4242",
}
var out struct{}
if err := srv.agent.RPC("Catalog.Register", args, &out); err != nil {
t.Fatalf("err: %v", err)
}
m := new(dns.Msg)
m.SetQuestion("bar.node.consul.", dns.TypeANY)
c := new(dns.Client)
addr, _ := srv.agent.config.ClientListener("", srv.agent.config.Ports.DNS)
in, _, err := c.Exchange(m, addr.String())
if err != nil {
t.Fatalf("err: %v", err)
}
if len(in.Answer) != 1 {
t.Fatalf("Bad: %#v", in)
}
aRec, ok := in.Answer[0].(*dns.AAAA)
if !ok {
t.Fatalf("Bad: %#v", in.Answer[0])
}
if aRec.AAAA.String() != "::4242:4242" {
t.Fatalf("Bad: %#v", in.Answer[0])
}
if aRec.Hdr.Ttl != 0 {
t.Fatalf("Bad: %#v", in.Answer[0])
}
}
// Retrieve the MX records for miek.nl.
func ExampleMX() {
config, _ := dns.ClientConfigFromFile("/etc/resolv.conf")
c := new(dns.Client)
m := new(dns.Msg)
m.SetQuestion("miek.nl.", dns.TypeMX)
m.RecursionDesired = true
r, _, err := c.Exchange(m, config.Servers[0]+":"+config.Port)
if err != nil {
return
}
if r.Rcode != dns.RcodeSuccess {
return
}
for _, a := range r.Answer {
if mx, ok := a.(*dns.MX); ok {
fmt.Printf("%s\n", mx.String())
}
}
}
func TestDNS_ReverseLookup_CustomDomain(t *testing.T) {
dir, srv := makeDNSServer(t)
defer os.RemoveAll(dir)
defer srv.agent.Shutdown()
srv.domain = dns.Fqdn("custom")
testutil.WaitForLeader(t, srv.agent.RPC, "dc1")
// Register node
args := &structs.RegisterRequest{
Datacenter: "dc1",
Node: "foo2",
Address: "127.0.0.2",
}
var out struct{}
if err := srv.agent.RPC("Catalog.Register", args, &out); err != nil {
t.Fatalf("err: %v", err)
}
m := new(dns.Msg)
m.SetQuestion("2.0.0.127.in-addr.arpa.", dns.TypeANY)
c := new(dns.Client)
addr, _ := srv.agent.config.ClientListener("", srv.agent.config.Ports.DNS)
in, _, err := c.Exchange(m, addr.String())
if err != nil {
t.Fatalf("err: %v", err)
}
if len(in.Answer) != 1 {
t.Fatalf("Bad: %#v", in)
}
ptrRec, ok := in.Answer[0].(*dns.PTR)
if !ok {
t.Fatalf("Bad: %#v", in.Answer[0])
}
if ptrRec.Ptr != "foo2.node.dc1.custom." {
t.Fatalf("Bad: %#v", ptrRec)
}
}
// handleQuery is used to handle an incoming query
func (s *server) handleQuery(query *dns.Msg, from net.Addr) error {
// Ignore answer for now
if len(query.Answer) > 0 {
return nil
}
// Ignore questions with Authorative section for now
if len(query.Ns) > 0 {
return nil
}
// Handle each question
var (
resp dns.Msg
err error
)
if len(query.Question) > 0 {
for i, _ := range query.Question {
resp = dns.Msg{}
resp.SetReply(query)
resp.Answer = []dns.RR{}
resp.Extra = []dns.RR{}
if err = s.handleQuestion(query.Question[i], &resp); err != nil {
log.Printf("[ERR] bonjour: failed to handle question %v: %v",
query.Question[i], err)
continue
}
// Check if there is an answer
if len(resp.Answer) > 0 {
//return s.sendResponse(&resp, from)
//log.Println("====== BEGIN ======")
//log.Println(resp.String())
//log.Println("======= END =======")
if e := s.multicastResponse(&resp); e != nil {
err = e
}
}
}
}
return err
}
// nodeLookup is used to handle a node query
func (d *DNSServer) nodeLookup(network, datacenter, node string, req, resp *dns.Msg) {
// Only handle ANY and A type requests
qType := req.Question[0].Qtype
if qType != dns.TypeANY && qType != dns.TypeA {
return
}
// Make an RPC request
args := structs.NodeSpecificRequest{
Datacenter: datacenter,
Node: node,
QueryOptions: structs.QueryOptions{AllowStale: d.config.AllowStale},
}
var out structs.IndexedNodeServices
RPC:
if err := d.agent.RPC("Catalog.NodeServices", &args, &out); err != nil {
d.logger.Printf("[ERR] dns: rpc error: %v", err)
resp.SetRcode(req, dns.RcodeServerFailure)
return
}
// Verify that request is not too stale, redo the request
if args.AllowStale && out.LastContact > d.config.MaxStale {
args.AllowStale = false
d.logger.Printf("[WARN] dns: Query results too stale, re-requesting")
goto RPC
}
// If we have no address, return not found!
if out.NodeServices == nil {
resp.SetRcode(req, dns.RcodeNameError)
return
}
// Add the node record
records := d.formatNodeRecord(&out.NodeServices.Node, out.NodeServices.Node.Address,
req.Question[0].Name, qType, d.config.NodeTTL)
if records != nil {
resp.Answer = append(resp.Answer, records...)
}
}
// handleTest is used to handle DNS queries in the ".consul." domain
func (d *DNSServer) handleTest(resp dns.ResponseWriter, req *dns.Msg) {
q := req.Question[0]
defer func(s time.Time) {
d.logger.Printf("[DEBUG] dns: request for %v (%v)", q, time.Now().Sub(s))
}(time.Now())
if !(q.Qtype == dns.TypeANY || q.Qtype == dns.TypeTXT) {
return
}
if q.Name != testQuery {
return
}
// Always respond with TXT "ok"
m := new(dns.Msg)
m.SetReply(req)
m.Authoritative = true
m.RecursionAvailable = true
header := dns.RR_Header{Name: q.Name, Rrtype: dns.TypeTXT, Class: dns.ClassINET, Ttl: 0}
txt := &dns.TXT{Hdr: header, Txt: []string{"ok"}}
m.Answer = append(m.Answer, txt)
d.addSOA(consulDomain, m)
if err := resp.WriteMsg(m); err != nil {
d.logger.Printf("[WARN] dns: failed to respond: %v", err)
}
}
// Performs the actual query by service name (browse) or service instance name (lookup),
// start response listeners goroutines and loops over the entries channel.
func (c *client) query(params *LookupParams) error {
var serviceName, serviceInstanceName string
serviceName = fmt.Sprintf("%s.%s.", trimDot(params.Service), trimDot(params.Domain))
if params.Instance != "" {
serviceInstanceName = fmt.Sprintf("%s.%s", params.Instance, serviceName)
}
// send the query
m := new(dns.Msg)
if serviceInstanceName != "" {
m.Question = []dns.Question{
dns.Question{serviceInstanceName, dns.TypeSRV, dns.ClassINET},
dns.Question{serviceInstanceName, dns.TypeTXT, dns.ClassINET},
}
m.RecursionDesired = false
} else {
m.SetQuestion(serviceName, dns.TypePTR)
m.RecursionDesired = false
}
if err := c.sendQuery(m); err != nil {
return err
}
return nil
}
// Data receiving routine reads from connection, unpacks packets into dns.Msg
// structures and sends them to a given msgCh channel
func (c *client) recv(l *net.UDPConn, msgCh chan *dns.Msg) {
if l == nil {
return
}
buf := make([]byte, 65536)
for !c.closed {
n, _, err := l.ReadFrom(buf)
if err != nil {
continue
}
msg := new(dns.Msg)
if err := msg.Unpack(buf[:n]); err != nil {
log.Printf("[ERR] mdns: Failed to unpack packet: %v", err)
continue
}
select {
case msgCh <- msg:
case <-c.closedCh:
return
}
}
}
// serviceARecords is used to add the SRV records for a service lookup
func (d *DNSServer) serviceSRVRecords(dc string, nodes structs.CheckServiceNodes, req, resp *dns.Msg, ttl time.Duration) {
handled := make(map[string]struct{})
for _, node := range nodes {
// Avoid duplicate entries, possible if a node has
// the same service the same port, etc.
tuple := fmt.Sprintf("%s:%s:%d", node.Node.Node, node.Service.Address, node.Service.Port)
if _, ok := handled[tuple]; ok {
continue
}
handled[tuple] = struct{}{}
// Add the SRV record
srvRec := &dns.SRV{
Hdr: dns.RR_Header{
Name: req.Question[0].Name,
Rrtype: dns.TypeSRV,
Class: dns.ClassINET,
Ttl: uint32(ttl / time.Second),
},
Priority: 1,
Weight: 1,
Port: uint16(node.Service.Port),
Target: fmt.Sprintf("%s.node.%s.%s", node.Node.Node, dc, d.domain),
}
resp.Answer = append(resp.Answer, srvRec)
// Determine advertised address
addr := node.Node.Address
if node.Service.Address != "" {
addr = node.Service.Address
}
// Add the extra record
records := d.formatNodeRecord(&node.Node, addr, srvRec.Target, dns.TypeANY, ttl)
if records != nil {
resp.Extra = append(resp.Extra, records...)
}
}
}
func TestDNS_Recurse(t *testing.T) {
dir, srv := makeDNSServer(t)
defer os.RemoveAll(dir)
defer srv.agent.Shutdown()
m := new(dns.Msg)
m.SetQuestion("apple.com.", dns.TypeANY)
c := new(dns.Client)
c.Net = "tcp"
addr, _ := srv.agent.config.ClientListener("", srv.agent.config.Ports.DNS)
in, _, err := c.Exchange(m, addr.String())
if err != nil {
t.Fatalf("err: %v", err)
}
if len(in.Answer) == 0 {
t.Fatalf("Bad: %#v", in)
}
if in.Rcode != dns.RcodeSuccess {
t.Fatalf("Bad: %#v", in)
}
}
// Perform probing & announcement
//TODO: implement a proper probing & conflict resolution
func (s *server) probe() {
q := new(dns.Msg)
q.SetQuestion(s.service.ServiceInstanceName(), dns.TypePTR)
q.RecursionDesired = false
srv := &dns.SRV{
Hdr: dns.RR_Header{
Name: s.service.ServiceInstanceName(),
Rrtype: dns.TypeSRV,
Class: dns.ClassINET,
Ttl: 3200,
},
Priority: 0,
Weight: 0,
Port: uint16(s.service.Port),
Target: s.service.HostName,
}
txt := &dns.TXT{
Hdr: dns.RR_Header{
Name: s.service.ServiceInstanceName(),
Rrtype: dns.TypeTXT,
Class: dns.ClassINET,
Ttl: 3200,
},
Txt: s.service.Text,
}
q.Ns = []dns.RR{srv, txt}
randomizer := rand.New(rand.NewSource(time.Now().UnixNano()))
for i := 0; i < 3; i++ {
if err := s.multicastResponse(q); err != nil {
log.Println("[ERR] bonjour: failed to send probe:", err.Error())
}
time.Sleep(time.Duration(randomizer.Intn(250)) * time.Millisecond)
}
resp := new(dns.Msg)
resp.Answer = []dns.RR{}
resp.Extra = []dns.RR{}
s.composeLookupAnswers(resp, 3200)
for i := 0; i < 3; i++ {
if err := s.multicastResponse(resp); err != nil {
log.Println("[ERR] bonjour: failed to send announcement:", err.Error())
}
time.Sleep(2 * time.Second)
}
}
// handleQUery is used to handle DNS queries in the configured domain
func (d *DNSServer) handleQuery(resp dns.ResponseWriter, req *dns.Msg) {
q := req.Question[0]
defer func(s time.Time) {
d.logger.Printf("[DEBUG] dns: request for %v (%v)", q, time.Now().Sub(s))
}(time.Now())
// Check if this is potentially a test query
if q.Name == testQuery {
d.handleTest(resp, req)
return
}
// Switch to TCP if the client is
network := "udp"
if _, ok := resp.RemoteAddr().(*net.TCPAddr); ok {
network = "tcp"
}
// Setup the message response
m := new(dns.Msg)
m.SetReply(req)
m.Authoritative = true
m.RecursionAvailable = (len(d.recursors) > 0)
// Only add the SOA if requested
if req.Question[0].Qtype == dns.TypeSOA {
d.addSOA(d.domain, m)
}
// Dispatch the correct handler
d.dispatch(network, req, m)
// Write out the complete response
if err := resp.WriteMsg(m); err != nil {
d.logger.Printf("[WARN] dns: failed to respond: %v", err)
}
}
// Retrieve the DNSKEY records of a zone and convert them
// to DS records for SHA1, SHA256 and SHA384.
func ExampleDS(zone string) {
config, _ := dns.ClientConfigFromFile("/etc/resolv.conf")
c := new(dns.Client)
m := new(dns.Msg)
if zone == "" {
zone = "miek.nl"
}
m.SetQuestion(dns.Fqdn(zone), dns.TypeDNSKEY)
m.SetEdns0(4096, true)
r, _, err := c.Exchange(m, config.Servers[0]+":"+config.Port)
if err != nil {
return
}
if r.Rcode != dns.RcodeSuccess {
return
}
for _, k := range r.Answer {
if key, ok := k.(*dns.DNSKEY); ok {
for _, alg := range []uint8{dns.SHA1, dns.SHA256, dns.SHA384} {
fmt.Printf("%s; %d\n", key.ToDS(alg).String(), key.Flags)
}
}
}
}
// addSOA is used to add an SOA record to a message for the given domain
func (d *DNSServer) addSOA(domain string, msg *dns.Msg) {
soa := &dns.SOA{
Hdr: dns.RR_Header{
Name: domain,
Rrtype: dns.TypeSOA,
Class: dns.ClassINET,
Ttl: 0,
},
Ns: "ns." + domain,
Mbox: "postmaster." + domain,
Serial: uint32(time.Now().Unix()),
Refresh: 3600,
Retry: 600,
Expire: 86400,
Minttl: 0,
}
msg.Ns = append(msg.Ns, soa)
}
// handlePtr is used to handle "reverse" DNS queries
func (d *DNSServer) handlePtr(resp dns.ResponseWriter, req *dns.Msg) {
q := req.Question[0]
defer func(s time.Time) {
d.logger.Printf("[DEBUG] dns: request for %v (%v)", q, time.Now().Sub(s))
}(time.Now())
// Setup the message response
m := new(dns.Msg)
m.SetReply(req)
m.Authoritative = true
m.RecursionAvailable = (len(d.recursors) > 0)
// Only add the SOA if requested
if req.Question[0].Qtype == dns.TypeSOA {
d.addSOA(d.domain, m)
}
datacenter := d.agent.config.Datacenter
// Get the QName without the domain suffix
qName := strings.ToLower(dns.Fqdn(req.Question[0].Name))
args := structs.DCSpecificRequest{
Datacenter: datacenter,
QueryOptions: structs.QueryOptions{AllowStale: d.config.AllowStale},
}
var out structs.IndexedNodes
// TODO: Replace ListNodes with an internal RPC that can do the filter
// server side to avoid transferring the entire node list.
if err := d.agent.RPC("Catalog.ListNodes", &args, &out); err == nil {
for _, n := range out.Nodes {
arpa, _ := dns.ReverseAddr(n.Address)
if arpa == qName {
ptr := &dns.PTR{
Hdr: dns.RR_Header{Name: q.Name, Rrtype: dns.TypePTR, Class: dns.ClassINET, Ttl: 0},
Ptr: fmt.Sprintf("%s.node.%s.%s", n.Node, datacenter, d.domain),
}
m.Answer = append(m.Answer, ptr)
break
}
}
}
// Write out the complete response
if err := resp.WriteMsg(m); err != nil {
d.logger.Printf("[WARN] dns: failed to respond: %v", err)
}
}
// serviceNodeRecords is used to add the node records for a service lookup
func (d *DNSServer) serviceNodeRecords(nodes structs.CheckServiceNodes, req, resp *dns.Msg, ttl time.Duration) {
qName := req.Question[0].Name
qType := req.Question[0].Qtype
handled := make(map[string]struct{})
for _, node := range nodes {
// Avoid duplicate entries, possible if a node has
// the same service on multiple ports, etc.
addr := node.Node.Address
if node.Service.Address != "" {
addr = node.Service.Address
}
if _, ok := handled[addr]; ok {
continue
}
handled[addr] = struct{}{}
// Add the node record
records := d.formatNodeRecord(&node.Node, addr, qName, qType, ttl)
if records != nil {
resp.Answer = append(resp.Answer, records...)
}
}
}
func TestDNS_ServiceLookup_FilterCritical(t *testing.T) {
dir, srv := makeDNSServer(t)
defer os.RemoveAll(dir)
defer srv.agent.Shutdown()
testutil.WaitForLeader(t, srv.agent.RPC, "dc1")
// Register nodes
args := &structs.RegisterRequest{
Datacenter: "dc1",
Node: "foo",
Address: "127.0.0.1",
Service: &structs.NodeService{
Service: "db",
Tags: []string{"master"},
Port: 12345,
},
Check: &structs.HealthCheck{
CheckID: "serf",
Name: "serf",
Status: structs.HealthCritical,
},
}
var out struct{}
if err := srv.agent.RPC("Catalog.Register", args, &out); err != nil {
t.Fatalf("err: %v", err)
}
args2 := &structs.RegisterRequest{
Datacenter: "dc1",
Node: "bar",
Address: "127.0.0.2",
Service: &structs.NodeService{
Service: "db",
Tags: []string{"master"},
Port: 12345,
},
Check: &structs.HealthCheck{
CheckID: "serf",
Name: "serf",
Status: structs.HealthCritical,
},
}
if err := srv.agent.RPC("Catalog.Register", args2, &out); err != nil {
t.Fatalf("err: %v", err)
}
args3 := &structs.RegisterRequest{
Datacenter: "dc1",
Node: "bar",
Address: "127.0.0.2",
Service: &structs.NodeService{
Service: "db",
Tags: []string{"master"},
Port: 12345,
},
Check: &structs.HealthCheck{
CheckID: "db",
Name: "db",
ServiceID: "db",
Status: structs.HealthCritical,
},
}
if err := srv.agent.RPC("Catalog.Register", args3, &out); err != nil {
t.Fatalf("err: %v", err)
}
args4 := &structs.RegisterRequest{
Datacenter: "dc1",
Node: "baz",
Address: "127.0.0.3",
Service: &structs.NodeService{
Service: "db",
Tags: []string{"master"},
Port: 12345,
},
}
if err := srv.agent.RPC("Catalog.Register", args4, &out); err != nil {
t.Fatalf("err: %v", err)
}
args5 := &structs.RegisterRequest{
Datacenter: "dc1",
Node: "quux",
Address: "127.0.0.4",
Service: &structs.NodeService{
Service: "db",
Tags: []string{"master"},
Port: 12345,
},
Check: &structs.HealthCheck{
CheckID: "db",
Name: "db",
ServiceID: "db",
Status: structs.HealthWarning,
},
}
if err := srv.agent.RPC("Catalog.Register", args5, &out); err != nil {
t.Fatalf("err: %v", err)
}
m := new(dns.Msg)
m.SetQuestion("db.service.consul.", dns.TypeANY)
c := new(dns.Client)
addr, _ := srv.agent.config.ClientListener("", srv.agent.config.Ports.DNS)
in, _, err := c.Exchange(m, addr.String())
if err != nil {
t.Fatalf("err: %v", err)
}
// Only 4 and 5 are not failing, so we should get 2 answers
if len(in.Answer) != 2 {
t.Fatalf("Bad: %#v", in)
}
ips := make(map[string]bool)
for _, resp := range in.Answer {
aRec := resp.(*dns.A)
ips[aRec.A.String()] = true
}
if !ips["127.0.0.3"] {
t.Fatalf("Bad: %#v should contain 127.0.0.3 (state healthy)", in)
}
if !ips["127.0.0.4"] {
t.Fatalf("Bad: %#v should contain 127.0.0.4 (state warning)", in)
}
}
