Simple RFC 2782 support with optional .service tag

Add support for SRV queries of names matching:
_<service>._<protocol>.[.service][.datacenter]<.domain>
This commit is contained in:
Patrick Sodré 2017-01-30 13:36:48 -05:00
parent a64dea878b
commit c135c08fb2
3 changed files with 104 additions and 76 deletions

View File

@ -304,12 +304,20 @@ func (d *DNSServer) dispatch(network string, req, resp *dns.Msg) {
// Split into the label parts
labels := dns.SplitDomainName(qName)
// The last label is either "node", "service", "query", or a datacenter name
// The last label is either "node", "service", "query", "_<protocol>", or a datacenter name
PARSE:
n := len(labels)
if n == 0 {
goto INVALID
}
// If this is a SRV query the "service" label is optional, we add it back to use the
// existing code-path.
if req.Question[0].Qtype == dns.TypeSRV && strings.HasPrefix(labels[n-1], "_") {
labels = append(labels, "service")
n = n + 1
}
switch labels[n-1] {
case "service":
if n == 1 {

View File

@ -3393,47 +3393,57 @@ func TestDNS_ServiceLookup_SRV_RFC(t *testing.T) {
t.Fatalf("err: %v", err)
}
m := new(dns.Msg)
m.SetQuestion("_db._master.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)
questions := []string{
"_db._master.service.dc1.consul.",
"_db._master.service.consul.",
"_db._master.dc1.consul.",
"_db._master.consul.",
}
if len(in.Answer) != 1 {
t.Fatalf("Bad: %#v", in)
for _, question := range questions {
m := new(dns.Msg)
m.SetQuestion(question, 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)
}
if srvRec.Hdr.Ttl != 0 {
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.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])
}
if aRec.Hdr.Ttl != 0 {
t.Fatalf("Bad: %#v", in.Extra[0])
}
}
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)
}
if srvRec.Hdr.Ttl != 0 {
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.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])
}
if aRec.Hdr.Ttl != 0 {
t.Fatalf("Bad: %#v", in.Extra[0])
}
}
func TestDNS_ServiceLookup_SRV_RFC_TCP_Default(t *testing.T) {
@ -3460,47 +3470,57 @@ func TestDNS_ServiceLookup_SRV_RFC_TCP_Default(t *testing.T) {
t.Fatalf("err: %v", err)
}
m := new(dns.Msg)
m.SetQuestion("_db._tcp.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)
questions := []string{
"_db._tcp.service.dc1.consul.",
"_db._tcp.service.consul.",
"_db._tcp.dc1.consul.",
"_db._tcp.consul.",
}
if len(in.Answer) != 1 {
t.Fatalf("Bad: %#v", in)
for _, question := range questions {
m := new(dns.Msg)
m.SetQuestion(question, 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)
}
if srvRec.Hdr.Ttl != 0 {
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.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])
}
if aRec.Hdr.Ttl != 0 {
t.Fatalf("Bad: %#v", in.Extra[0])
}
}
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)
}
if srvRec.Hdr.Ttl != 0 {
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.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])
}
if aRec.Hdr.Ttl != 0 {
t.Fatalf("Bad: %#v", in.Extra[0])
}
}
func TestDNS_ServiceLookup_FilterACL(t *testing.T) {

View File

@ -138,7 +138,7 @@ foobar.node.dc1.consul. 0 IN A 10.1.10.12
The format for RFC 2782 SRV lookups is:
_<service>._<protocol>.service[.datacenter][.domain]
_<service>._<protocol>[.service][.datacenter][.domain]
Per [RFC 2782](https://tools.ietf.org/html/rfc2782), SRV queries should use
underscores, `_`, as a prefix to the `service` and `protocol` values in a query to