// 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_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 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)
}
}
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)
}
}
// 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)
}
}
}
}
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_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)
}
}
// 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")
}
}
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)
}
}