Merge pull request #1194 from 42wim/fix-maxServiceResponses

Limit the DNS responses after getting the NodeRecords (fixes 0 A/AAAA responses)
This commit is contained in:
Ryan Breen 2015-09-01 17:41:39 -04:00
commit 0bd7211eab
2 changed files with 76 additions and 11 deletions

View File

@ -511,16 +511,6 @@ RPC:
// 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 {
resp.Truncated = true
}
}
// Add various responses depending on the request
qType := req.Question[0].Qtype
d.serviceNodeRecords(out.Nodes, req, resp, ttl)
@ -529,13 +519,22 @@ RPC:
d.serviceSRVRecords(datacenter, out.Nodes, req, resp, ttl)
}
// If the network is not TCP, restrict the number of responses
if network != "tcp" && len(resp.Answer) > maxServiceResponses {
resp.Answer = resp.Answer[:maxServiceResponses]
// Flag that there are more records to return in the UDP response
if d.config.EnableTruncate {
resp.Truncated = true
}
}
// If the answer is empty, return not found
if len(resp.Answer) == 0 {
d.addSOA(d.domain, resp)
resp.SetRcode(req, dns.RcodeNameError)
return
}
}
// filterServiceNodes is used to filter out nodes that are failing

View File

@ -1416,6 +1416,72 @@ func TestDNS_ServiceLookup_Truncate(t *testing.T) {
}
}
func TestDNS_ServiceLookup_MaxResponses(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 < 6*maxServiceResponses; i++ {
nodeAddress := fmt.Sprintf("127.0.0.%d", i+1)
if i > 3 {
nodeAddress = fmt.Sprintf("fe80::%d", i+1)
}
args := &structs.RegisterRequest{
Datacenter: "dc1",
Node: fmt.Sprintf("foo%d", i),
Address: nodeAddress,
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.
m := new(dns.Msg)
m.SetQuestion("web.service.consul.", dns.TypeANY)
addr, _ := srv.agent.config.ClientListener("", srv.agent.config.Ports.DNS)
c := new(dns.Client)
in, _, err := c.Exchange(m, addr.String())
if err != nil {
t.Fatalf("err: %v", err)
}
if len(in.Answer) != 3 {
t.Fatalf("should receive 3 answers for ANY")
}
m.SetQuestion("web.service.consul.", dns.TypeA)
in, _, err = c.Exchange(m, addr.String())
if err != nil {
t.Fatalf("err: %v", err)
}
if len(in.Answer) != 3 {
t.Fatalf("should receive 3 answers for A")
}
m.SetQuestion("web.service.consul.", dns.TypeAAAA)
in, _, err = c.Exchange(m, addr.String())
if err != nil {
t.Fatalf("err: %v", err)
}
if len(in.Answer) != 3 {
t.Fatalf("should receive 3 answers for AAAA")
}
}
func TestDNS_ServiceLookup_CNAME(t *testing.T) {
recursor := makeRecursor(t, []dns.RR{
dnsCNAME("www.google.com", "google.com"),