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-rw-r--r--middleware/etcd/cname_test.go96
-rw-r--r--middleware/loadbalance/loadbalance.go23
-rw-r--r--middleware/loadbalance/loadbalance.md4
-rw-r--r--middleware/loadbalance/loadbalance_test.go104
4 files changed, 216 insertions, 11 deletions
diff --git a/middleware/etcd/cname_test.go b/middleware/etcd/cname_test.go
new file mode 100644
index 000000000..7d53bfef6
--- /dev/null
+++ b/middleware/etcd/cname_test.go
@@ -0,0 +1,96 @@
+// +build etcd
+
+package etcd
+
+// etcd needs to be running on http://127.0.0.1:2379
+
+import (
+ "testing"
+
+ "github.com/miekg/coredns/middleware"
+ "github.com/miekg/coredns/middleware/etcd/msg"
+
+ "github.com/miekg/dns"
+)
+
+// Check the ordering of returned cname.
+func TestCnameLookup(t *testing.T) {
+ for _, serv := range servicesCname {
+ set(t, etc, serv.Key, 0, serv)
+ defer delete(t, etc, serv.Key)
+ }
+ for _, tc := range dnsTestCasesCname {
+ m := new(dns.Msg)
+ m.SetQuestion(dns.Fqdn(tc.Qname), tc.Qtype)
+
+ rec := middleware.NewResponseRecorder(&middleware.TestResponseWriter{})
+ _, err := etc.ServeDNS(ctx, rec, m)
+ if err != nil {
+ t.Errorf("expected no error, got %v\n", err)
+ return
+ }
+ resp := rec.Msg()
+
+ if resp.Rcode != tc.Rcode {
+ t.Errorf("rcode is %q, expected %q", dns.RcodeToString[resp.Rcode], dns.RcodeToString[tc.Rcode])
+ t.Logf("%v\n", resp)
+ continue
+ }
+
+ if len(resp.Answer) != len(tc.Answer) {
+ t.Errorf("answer for %q contained %d results, %d expected", tc.Qname, len(resp.Answer), len(tc.Answer))
+ t.Logf("%v\n", resp)
+ continue
+ }
+ if len(resp.Ns) != len(tc.Ns) {
+ t.Errorf("authority for %q contained %d results, %d expected", tc.Qname, len(resp.Ns), len(tc.Ns))
+ t.Logf("%v\n", resp)
+ continue
+ }
+ if len(resp.Extra) != len(tc.Extra) {
+ t.Errorf("additional for %q contained %d results, %d expected", tc.Qname, len(resp.Extra), len(tc.Extra))
+ t.Logf("%v\n", resp)
+ continue
+ }
+
+ if !checkSection(t, tc, Answer, resp.Answer) {
+ t.Logf("%v\n", resp)
+ }
+ if !checkSection(t, tc, Ns, resp.Ns) {
+ t.Logf("%v\n", resp)
+
+ }
+ if !checkSection(t, tc, Extra, resp.Extra) {
+ t.Logf("%v\n", resp)
+ }
+ }
+}
+
+var servicesCname = []*msg.Service{
+ {Host: "cname1.region2.skydns.test", Key: "a.server1.dev.region1.skydns.test."},
+ {Host: "cname2.region2.skydns.test", Key: "cname1.region2.skydns.test."},
+ {Host: "cname3.region2.skydns.test", Key: "cname2.region2.skydns.test."},
+ {Host: "cname4.region2.skydns.test", Key: "cname3.region2.skydns.test."},
+ {Host: "cname5.region2.skydns.test", Key: "cname4.region2.skydns.test."},
+ {Host: "cname6.region2.skydns.test", Key: "cname5.region2.skydns.test."},
+ {Host: "endpoint.region2.skydns.test", Key: "cname6.region2.skydns.test."},
+ {Host: "10.240.0.1", Key: "endpoint.region2.skydns.test."},
+}
+
+var dnsTestCasesCname = []dnsTestCase{
+ {
+ Qname: "a.server1.dev.region1.skydns.test.", Qtype: dns.TypeSRV,
+ Answer: []dns.RR{
+ newSRV("a.server1.dev.region1.skydns.test. 300 IN SRV 10 100 0 cname1.region2.skydns.test."),
+ },
+ Extra: []dns.RR{
+ newCNAME("cname1.region2.skydns.test. 300 IN CNAME cname2.region2.skydns.test."),
+ newCNAME("cname2.region2.skydns.test. 300 IN CNAME cname3.region2.skydns.test."),
+ newCNAME("cname3.region2.skydns.test. 300 IN CNAME cname4.region2.skydns.test."),
+ newCNAME("cname4.region2.skydns.test. 300 IN CNAME cname5.region2.skydns.test."),
+ newCNAME("cname5.region2.skydns.test. 300 IN CNAME cname6.region2.skydns.test."),
+ newCNAME("cname6.region2.skydns.test. 300 IN CNAME endpoint.region2.skydns.test."),
+ newA("endpoint.region2.skydns.test. 300 IN A 10.240.0.1"),
+ },
+ },
+}
diff --git a/middleware/loadbalance/loadbalance.go b/middleware/loadbalance/loadbalance.go
index c81ad0c8a..e1bee25fd 100644
--- a/middleware/loadbalance/loadbalance.go
+++ b/middleware/loadbalance/loadbalance.go
@@ -14,18 +14,21 @@ func (r *RoundRobinResponseWriter) WriteMsg(res *dns.Msg) error {
if res.Rcode != dns.RcodeSuccess {
return r.ResponseWriter.WriteMsg(res)
}
- if len(res.Answer) < 2 { // don't even bother
- return r.ResponseWriter.WriteMsg(res)
- }
- // put CNAMEs first, randomize a/aaaa's and put packet back together.
- // TODO(miek): check family and give v6 more prio?
+ res.Answer = roundRobin(res.Answer)
+ res.Extra = roundRobin(res.Extra)
+
+ return r.ResponseWriter.WriteMsg(res)
+}
+
+func roundRobin(in []dns.RR) []dns.RR {
cname := []dns.RR{}
address := []dns.RR{}
rest := []dns.RR{}
- for _, r := range res.Answer {
+ for _, r := range in {
switch r.Header().Rrtype {
case dns.TypeCNAME:
+ // d d d d DNAME and friends here as well?
cname = append(cname, r)
case dns.TypeA, dns.TypeAAAA:
address = append(address, r)
@@ -36,7 +39,7 @@ func (r *RoundRobinResponseWriter) WriteMsg(res *dns.Msg) error {
switch l := len(address); l {
case 0, 1:
- return r.ResponseWriter.WriteMsg(res)
+ break
case 2:
if dns.Id()%2 == 0 {
address[0], address[1] = address[1], address[0]
@@ -51,9 +54,9 @@ func (r *RoundRobinResponseWriter) WriteMsg(res *dns.Msg) error {
address[q], address[p] = address[p], address[q]
}
}
- res.Answer = append(cname, rest...)
- res.Answer = append(res.Answer, address...)
- return r.ResponseWriter.WriteMsg(res)
+ out := append(cname, rest...)
+ out = append(out, address...)
+ return out
}
// Should we pack and unpack here to fiddle with the packet... Not likely.
diff --git a/middleware/loadbalance/loadbalance.md b/middleware/loadbalance/loadbalance.md
index 0e931fb53..5c381135d 100644
--- a/middleware/loadbalance/loadbalance.md
+++ b/middleware/loadbalance/loadbalance.md
@@ -4,13 +4,15 @@
message. See [Wikipedia](https://en.wikipedia.org/wiki/Round-robin_DNS) about the pros and cons
on this setup.
+It will take care to sort any CNAMEs before any address records.
+
## Syntax
~~~
loadbalance [policy]
~~~
-* policy is how to balance, the default is "round_robin"
+* `policy` is how to balance, the default is "round_robin"
## Examples
diff --git a/middleware/loadbalance/loadbalance_test.go b/middleware/loadbalance/loadbalance_test.go
new file mode 100644
index 000000000..dc027607c
--- /dev/null
+++ b/middleware/loadbalance/loadbalance_test.go
@@ -0,0 +1,104 @@
+package loadbalance
+
+import (
+ "testing"
+
+ "github.com/miekg/coredns/middleware"
+
+ "github.com/miekg/dns"
+ "golang.org/x/net/context"
+)
+
+func TestLoadBalance(t *testing.T) {
+ rm := RoundRobin{Next: handler()}
+
+ // the first X records must be cnames after this test
+ tests := []struct {
+ answer []dns.RR
+ extra []dns.RR
+ cnameAnswer int
+ cnameExtra int
+ }{
+ {
+ answer: []dns.RR{
+ newCNAME("cname1.region2.skydns.test. 300 IN CNAME cname2.region2.skydns.test."),
+ newCNAME("cname2.region2.skydns.test. 300 IN CNAME cname3.region2.skydns.test."),
+ newCNAME("cname5.region2.skydns.test. 300 IN CNAME cname6.region2.skydns.test."),
+ newCNAME("cname6.region2.skydns.test. 300 IN CNAME endpoint.region2.skydns.test."),
+ newA("endpoint.region2.skydns.test. 300 IN A 10.240.0.1"),
+ },
+ cnameAnswer: 4,
+ },
+ {
+ answer: []dns.RR{
+ newA("endpoint.region2.skydns.test. 300 IN A 10.240.0.1"),
+ newCNAME("cname.region2.skydns.test. 300 IN CNAME endpoint.region2.skydns.test."),
+ },
+ cnameAnswer: 1,
+ },
+ {
+ answer: []dns.RR{
+ newA("endpoint.region2.skydns.test. 300 IN A 10.240.0.1"),
+ newA("endpoint.region2.skydns.test. 300 IN A 10.240.0.2"),
+ newCNAME("cname2.region2.skydns.test. 300 IN CNAME cname3.region2.skydns.test."),
+ newA("endpoint.region2.skydns.test. 300 IN A 10.240.0.3"),
+ },
+ extra: []dns.RR{
+ newA("endpoint.region2.skydns.test. 300 IN A 10.240.0.1"),
+ newAAAA("endpoint.region2.skydns.test. 300 IN AAAA ::1"),
+ newCNAME("cname2.region2.skydns.test. 300 IN CNAME cname3.region2.skydns.test."),
+ newA("endpoint.region2.skydns.test. 300 IN A 10.240.0.3"),
+ newAAAA("endpoint.region2.skydns.test. 300 IN AAAA ::2"),
+ },
+ cnameAnswer: 1,
+ cnameExtra: 1,
+ },
+ }
+
+ rec := middleware.NewResponseRecorder(&middleware.TestResponseWriter{})
+
+ for i, test := range tests {
+ req := new(dns.Msg)
+ req.SetQuestion("region2.skydns.test.", dns.TypeSRV)
+ req.Answer = test.answer
+ req.Extra = test.extra
+
+ _, err := rm.ServeDNS(context.TODO(), rec, req)
+ if err != nil {
+ t.Errorf("Test %d: Expected no error, but got %s", i, err)
+ continue
+
+ }
+ cname := 0
+ for _, r := range rec.Msg().Answer {
+ if r.Header().Rrtype != dns.TypeCNAME {
+ break
+ }
+ cname++
+ }
+ if cname != test.cnameAnswer {
+ t.Errorf("Test %d: Expected %d cnames in Answer, but got %d", i, test.cnameAnswer, cname)
+ }
+ cname = 0
+ for _, r := range rec.Msg().Extra {
+ if r.Header().Rrtype != dns.TypeCNAME {
+ break
+ }
+ cname++
+ }
+ if cname != test.cnameExtra {
+ t.Errorf("Test %d: Expected %d cname in Extra, but got %d", i, test.cnameExtra, cname)
+ }
+ }
+}
+
+func handler() middleware.Handler {
+ return middleware.HandlerFunc(func(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
+ w.WriteMsg(r)
+ return dns.RcodeSuccess, nil
+ })
+}
+
+func newA(rr string) *dns.A { r, _ := dns.NewRR(rr); return r.(*dns.A) }
+func newAAAA(rr string) *dns.AAAA { r, _ := dns.NewRR(rr); return r.(*dns.AAAA) }
+func newCNAME(rr string) *dns.CNAME { r, _ := dns.NewRR(rr); return r.(*dns.CNAME) }
generated by cgit v1.2.3 (git 2.46.0) at 2025-09-02 20:07:11 +0000