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])
}
}
// 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
}
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_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 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 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])
}
}
}
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)
}
}
// 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)
}
}
// 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)
}
}
// 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_OnlyPassing(t *testing.T) {
dir, srv := makeDNSServerConfig(t, &DNSConfig{OnlyPassing: true})
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: "db",
Name: "db",
ServiceID: "db",
Status: structs.HealthPassing,
},
}
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: "db",
Name: "db",
ServiceID: "db",
Status: structs.HealthWarning,
},
}
if err := srv.agent.RPC("Catalog.Register", args2, &out); err != nil {
t.Fatalf("err: %v", err)
}
args3 := &structs.RegisterRequest{
Datacenter: "dc1",
Node: "baz",
Address: "127.0.0.3",
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: "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.HealthUnknown,
},
}
if err := srv.agent.RPC("Catalog.Register", args4, &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 1 is passing, so we should only get 1 answer
if len(in.Answer) != 1 {
t.Fatalf("Bad: %#v", in)
}
resp := in.Answer[0]
aRec := resp.(*dns.A)
if aRec.A.String() != "127.0.0.1" {
t.Fatalf("Bad: %#v", in.Answer[0])
}
}
func TestDNS_NodeLookup_TTL(t *testing.T) {
config := &DNSConfig{
NodeTTL: 10 * time.Second,
AllowStale: true,
MaxStale: time.Second,
}
dir, srv := makeDNSServerConfig(t, config)
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.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.A)
if !ok {
t.Fatalf("Bad: %#v", in.Answer[0])
}
if aRec.A.String() != "127.0.0.1" {
t.Fatalf("Bad: %#v", in.Answer[0])
}
if aRec.Hdr.Ttl != 10 {
t.Fatalf("Bad: %#v", in.Answer[0])
}
// Register node with IPv6
args = &structs.RegisterRequest{
Datacenter: "dc1",
Node: "bar",
Address: "::4242:4242",
}
if err := srv.agent.RPC("Catalog.Register", args, &out); err != nil {
t.Fatalf("err: %v", err)
}
// Check an IPv6 record
m = new(dns.Msg)
m.SetQuestion("bar.node.consul.", dns.TypeANY)
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)
}
aaaaRec, ok := in.Answer[0].(*dns.AAAA)
if !ok {
t.Fatalf("Bad: %#v", in.Answer[0])
}
if aaaaRec.AAAA.String() != "::4242:4242" {
t.Fatalf("Bad: %#v", in.Answer[0])
}
if aaaaRec.Hdr.Ttl != 10 {
t.Fatalf("Bad: %#v", in.Answer[0])
}
// Register node with CNAME
args = &structs.RegisterRequest{
Datacenter: "dc1",
Node: "google",
Address: "www.google.com",
}
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)
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 != 10 {
t.Fatalf("Bad: %#v", in.Answer[0])
}
}
func TestDNS_ServiceLookup_TTL(t *testing.T) {
config := &DNSConfig{
ServiceTTL: map[string]time.Duration{
"db": 10 * time.Second,
"*": 5 * time.Second,
},
AllowStale: true,
MaxStale: time.Second,
}
dir, srv := makeDNSServerConfig(t, config)
defer os.RemoveAll(dir)
defer srv.agent.Shutdown()
testutil.WaitForLeader(t, srv.agent.RPC, "dc1")
// Register node with 2 services
args := &structs.RegisterRequest{
Datacenter: "dc1",
Node: "foo",
Address: "127.0.0.1",
Service: &structs.NodeService{
Service: "db",
Tags: []string{"master"},
Port: 12345,
},
}
var out struct{}
if err := srv.agent.RPC("Catalog.Register", args, &out); err != nil {
t.Fatalf("err: %v", err)
}
args = &structs.RegisterRequest{
Datacenter: "dc1",
Node: "foo",
Address: "127.0.0.1",
Service: &structs.NodeService{
Service: "api",
Port: 2222,
},
}
if err := srv.agent.RPC("Catalog.Register", args, &out); err != nil {
t.Fatalf("err: %v", err)
}
m := new(dns.Msg)
m.SetQuestion("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.Hdr.Ttl != 10 {
t.Fatalf("Bad: %#v", in.Answer[0])
}
aRec, ok := in.Extra[0].(*dns.A)
if !ok {
t.Fatalf("Bad: %#v", in.Extra[0])
}
if aRec.Hdr.Ttl != 10 {
t.Fatalf("Bad: %#v", in.Extra[0])
}
m = new(dns.Msg)
m.SetQuestion("api.service.consul.", dns.TypeSRV)
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.Hdr.Ttl != 5 {
t.Fatalf("Bad: %#v", in.Answer[0])
}
aRec, ok = in.Extra[0].(*dns.A)
if !ok {
t.Fatalf("Bad: %#v", in.Extra[0])
}
if aRec.Hdr.Ttl != 5 {
t.Fatalf("Bad: %#v", in.Extra[0])
}
}
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)
}
}
func TestDNS_ServiceLookup_Randomize(t *testing.T) {
dir, srv := makeDNSServer(t)
defer os.RemoveAll(dir)
defer srv.agent.Shutdown()
testutil.WaitForLeader(t, srv.agent.RPC, "dc1")
// Register nodes
for i := 0; i < 3*maxServiceResponses; i++ {
args := &structs.RegisterRequest{
Datacenter: "dc1",
Node: fmt.Sprintf("foo%d", i),
Address: fmt.Sprintf("127.0.0.%d", i+1),
Service: &structs.NodeService{
Service: "web",
Port: 8000,
},
}
var out struct{}
if err := srv.agent.RPC("Catalog.Register", args, &out); err != nil {
t.Fatalf("err: %v", err)
}
}
// Ensure the response is randomized each time.
loops := 5
uniques := map[string]struct{}{}
addr, _ := srv.agent.config.ClientListener("", srv.agent.config.Ports.DNS)
for i := 0; i < loops; i++ {
m := new(dns.Msg)
m.SetQuestion("web.service.consul.", dns.TypeANY)
c := new(dns.Client)
in, _, err := c.Exchange(m, addr.String())
if err != nil {
t.Fatalf("err: %v", err)
}
// Response length should be truncated
// We should get an A record for each response
if len(in.Answer) != maxServiceResponses {
t.Fatalf("Bad: %#v", len(in.Answer))
}
// Collect all the names
var names []string
for _, rec := range in.Answer {
switch v := rec.(type) {
case *dns.SRV:
names = append(names, v.Target)
case *dns.A:
names = append(names, v.A.String())
}
}
nameS := strings.Join(names, "|")
// Tally the results
uniques[nameS] = struct{}{}
}
// Give some wiggle room. Since the responses are randomized and there
// is a finite number of combinations, requiring 0 duplicates every
// test run eventually gives us failures.
if len(uniques) < (loops - 1) {
t.Fatalf("unique response ratio too low: %d/%d\n%v",
len(uniques), loops, uniques)
}
}
// serviceLookup is used to handle a service query
func (d *DNSServer) serviceLookup(network, datacenter, service, tag string, req, resp *dns.Msg) {
// Make an RPC request
args := structs.ServiceSpecificRequest{
Datacenter: datacenter,
ServiceName: service,
ServiceTag: tag,
TagFilter: tag != "",
QueryOptions: structs.QueryOptions{AllowStale: d.config.AllowStale},
}
var out structs.IndexedCheckServiceNodes
RPC:
if err := d.agent.RPC("Health.ServiceNodes", &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 nodes, return not found!
if len(out.Nodes) == 0 {
resp.SetRcode(req, dns.RcodeNameError)
return
}
// Determine the TTL
var ttl time.Duration
if d.config.ServiceTTL != nil {
var ok bool
ttl, ok = d.config.ServiceTTL[service]
if !ok {
ttl = d.config.ServiceTTL["*"]
}
}
// Filter out any service nodes due to health checks
out.Nodes = d.filterServiceNodes(out.Nodes)
// Perform a random shuffle
shuffleServiceNodes(out.Nodes)
// If the network is not TCP, restrict the number of responses
if network != "tcp" && len(out.Nodes) > maxServiceResponses {
out.Nodes = out.Nodes[:maxServiceResponses]
// Flag that there are more records to return in the UDP response
if d.config.EnableTruncate == true {
resp.Truncated = true
}
}
// Add various responses depending on the request
qType := req.Question[0].Qtype
d.serviceNodeRecords(out.Nodes, req, resp, ttl)
if qType == dns.TypeSRV {
d.serviceSRVRecords(datacenter, out.Nodes, req, resp, ttl)
}
}
// NewDNSServer starts a new DNS server to provide an agent interface
func NewDNSServer(agent *Agent, config *DNSConfig, logOutput io.Writer, domain string, bind string, recursors []string) (*DNSServer, error) {
// Make sure domain is FQDN
domain = dns.Fqdn(domain)
// Construct the DNS components
mux := dns.NewServeMux()
// Setup the servers
server := &dns.Server{
Addr: bind,
Net: "udp",
Handler: mux,
UDPSize: 65535,
}
serverTCP := &dns.Server{
Addr: bind,
Net: "tcp",
Handler: mux,
}
// Create the server
srv := &DNSServer{
agent: agent,
config: config,
dnsHandler: mux,
dnsServer: server,
dnsServerTCP: serverTCP,
domain: domain,
recursors: recursors,
logger: log.New(logOutput, "", log.LstdFlags),
}
// Register mux handler, for reverse lookup
mux.HandleFunc("arpa.", srv.handlePtr)
// Register mux handlers, always handle "consul."
mux.HandleFunc(domain, srv.handleQuery)
if domain != consulDomain {
mux.HandleFunc(consulDomain, srv.handleTest)
}
if len(recursors) > 0 {
validatedRecursors := make([]string, len(recursors))
for idx, recursor := range recursors {
recursor, err := recursorAddr(recursor)
if err != nil {
return nil, fmt.Errorf("Invalid recursor address: %v", err)
}
validatedRecursors[idx] = recursor
}
srv.recursors = validatedRecursors
mux.HandleFunc(".", srv.handleRecurse)
}
// Async start the DNS Servers, handle a potential error
errCh := make(chan error, 1)
go func() {
if err := server.ListenAndServe(); err != nil {
srv.logger.Printf("[ERR] dns: error starting udp server: %v", err)
errCh <- fmt.Errorf("dns udp setup failed: %v", err)
}
}()
errChTCP := make(chan error, 1)
go func() {
if err := serverTCP.ListenAndServe(); err != nil {
srv.logger.Printf("[ERR] dns: error starting tcp server: %v", err)
errChTCP <- fmt.Errorf("dns tcp setup failed: %v", err)
}
}()
// Check the server is running, do a test lookup
checkCh := make(chan error, 1)
go func() {
// This is jank, but we have no way to edge trigger on
// the start of our server, so we just wait and hope it is up.
time.Sleep(50 * time.Millisecond)
m := new(dns.Msg)
m.SetQuestion(testQuery, dns.TypeANY)
c := new(dns.Client)
in, _, err := c.Exchange(m, bind)
if err != nil {
checkCh <- fmt.Errorf("dns test query failed: %v", err)
return
}
if len(in.Answer) == 0 {
checkCh <- fmt.Errorf("no response to test message")
return
}
close(checkCh)
}()
// Wait for either the check, listen error, or timeout
select {
case e := <-errCh:
return srv, e
case e := <-errChTCP:
return srv, e
case e := <-checkCh:
return srv, e
case <-time.After(time.Second):
return srv, fmt.Errorf("timeout setting up DNS server")
}
}
// dispatch is used to parse a request and invoke the correct handler
func (d *DNSServer) dispatch(network string, req, resp *dns.Msg) {
// By default the query is in the default datacenter
datacenter := d.agent.config.Datacenter
// Get the QName without the domain suffix
qName := strings.ToLower(dns.Fqdn(req.Question[0].Name))
qName = strings.TrimSuffix(qName, d.domain)
// Split into the label parts
labels := dns.SplitDomainName(qName)
// The last label is either "node", "service" or a datacenter name
PARSE:
n := len(labels)
if n == 0 {
goto INVALID
}
switch labels[n-1] {
case "service":
if n == 1 {
goto INVALID
}
// Support RFC 2782 style syntax
if n == 3 && strings.HasPrefix(labels[n-2], "_") && strings.HasPrefix(labels[n-3], "_") {
// Grab the tag since we make nuke it if it's tcp
tag := labels[n-2][1:]
// Treat _name._tcp.service.consul as a default, no need to filter on that tag
if tag == "tcp" {
tag = ""
}
// _name._tag.service.consul
d.serviceLookup(network, datacenter, labels[n-3][1:], tag, req, resp)
// Consul 0.3 and prior format for SRV queries
} else {
// Support "." in the label, re-join all the parts
tag := ""
if n >= 3 {
tag = strings.Join(labels[:n-2], ".")
}
// tag[.tag].name.service.consul
d.serviceLookup(network, datacenter, labels[n-2], tag, req, resp)
}
case "node":
if len(labels) == 1 {
goto INVALID
}
// Allow a "." in the node name, just join all the parts
node := strings.Join(labels[:n-1], ".")
d.nodeLookup(network, datacenter, node, req, resp)
default:
// Store the DC, and re-parse
datacenter = labels[n-1]
labels = labels[:n-1]
goto PARSE
}
return
INVALID:
d.logger.Printf("[WARN] dns: QName invalid: %s", qName)
resp.SetRcode(req, dns.RcodeNameError)
}