zettio/weave#362 - properly test the TCP-retry mechanism by creating fallback servers that return truncated responses with UDP but not with TCP
This commit is contained in:
Alvaro Saurin committed
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3de924fa2f
commit
f8b3c86498
2 files changed
+128
-63
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+110
-63
@@ -1,6 +1,7 @@
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package nameserver
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import (
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"encoding/binary"
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"fmt"
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"github.com/miekg/dns"
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. "github.com/zettio/weave/common"
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@@ -32,8 +33,32 @@ func TestUDPDNSServer(t *testing.T) {
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ip, _, _ := net.ParseCIDR(testCIDR1)
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zone.AddRecord(containerID, successTestName, ip)
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fallbackHandler := func(w dns.ResponseWriter, req *dns.Msg) {
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m := new(dns.Msg)
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m.SetReply(req)
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if len(req.Question) == 1 {
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q := req.Question[0]
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if q.Name == "weave.works." && q.Qtype == dns.TypeMX {
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m.Answer = make([]dns.RR, 1)
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m.Answer[0] = &dns.MX{Hdr: dns.RR_Header{Name: m.Question[0].Name, Rrtype: dns.TypeMX, Class: dns.ClassINET, Ttl: 0}, Mx: "mail.weave.works."}
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} else if q.Name == "weave.works." && q.Qtype == dns.TypeANY {
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const N = 10
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m.Extra = make([]dns.RR, N)
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for i, _ := range m.Extra {
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m.Extra[i] = &dns.TXT{Hdr: dns.RR_Header{Name: m.Question[0].Name, Rrtype: dns.TypeTXT, Class: dns.ClassINET, Ttl: 0}, Txt: []string{"Lots and lots and lots and lots and lots and lots and lots and lots and lots of data"}}
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}
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} else if q.Name == testRDNSnonlocal && q.Qtype == dns.TypePTR {
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m.Answer = make([]dns.RR, 1)
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m.Answer[0] = &dns.PTR{Hdr: dns.RR_Header{Name: m.Question[0].Name, Rrtype: dns.TypePTR, Class: dns.ClassINET, Ttl: 0}, Ptr: "ns1.google.com."}
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} else if q.Name == testRDNSfail && q.Qtype == dns.TypePTR {
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m.Rcode = dns.RcodeNameError
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}
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}
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w.WriteMsg(m)
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}
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// Run another DNS server for fallback
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s, fallbackAddr, err := RunLocalUDPServer("127.0.0.1:0")
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s, fallbackAddr, err := RunLocalUDPServer(t, "127.0.0.1:0", fallbackHandler)
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wt.AssertNoErr(t, err)
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defer s.Shutdown()
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@@ -118,34 +143,52 @@ func TestUDPDNSServer(t *testing.T) {
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func TestTCPDNSServer(t *testing.T) {
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const (
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port = 17625
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localTestName = "test1.weave.local."
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testAddr1 = "10.0.2.1"
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port = 17625
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numAnswers = 512
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nonLocalName = "weave.works."
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)
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dnsAddr := fmt.Sprintf("localhost:%d", port)
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InitDefaultLogging(true)
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var zone = new(ZoneDb)
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// Insert a bunch of IPs for the same name
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ansCount := 0
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for i := 0; i < 255; i++ {
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for j := 0; j < 10; j++ {
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ip := net.ParseIP(fmt.Sprintf("10.0.%d.%d", i, j))
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ansCount += 1
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err := zone.AddRecord(containerID, localTestName, ip)
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wt.AssertNoErr(t, err)
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}
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var addrs []net.IP
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bs := make([]byte, 4)
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for i := 0; i < numAnswers; i++ {
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binary.LittleEndian.PutUint32(bs, uint32(i))
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addrs = append(addrs, net.IPv4(bs[0], bs[1], bs[2], bs[3]))
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}
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// handler for the fallback server: it will just return a very long response
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fallbackUDPHandler := func(w dns.ResponseWriter, req *dns.Msg) {
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t.Logf("Fallback UDP server got asked: returning %d answers", numAnswers)
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q := req.Question[0]
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m := makeAddressReply(req, &q, addrs)
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m.Truncated = true
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w.WriteMsg(m)
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}
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fallbackTCPHandler := func(w dns.ResponseWriter, req *dns.Msg) {
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t.Logf("Fallback TCP server got asked: returning %d answers", numAnswers)
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q := req.Question[0]
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m := makeAddressReply(req, &q, addrs)
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w.WriteMsg(m)
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}
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// Run another DNS server for fallback
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s, fallbackAddr, err := RunLocalUDPServer("127.0.0.1:0")
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us, fallbackUdpAddr, err := RunLocalUDPServer(t, "127.0.0.1:0", fallbackUDPHandler)
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wt.AssertNoErr(t, err)
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defer s.Shutdown()
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defer us.Shutdown()
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_, fallbackPort, err := net.SplitHostPort(fallbackAddr)
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_, fallbackPort, err := net.SplitHostPort(fallbackUdpAddr)
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wt.AssertNoErr(t, err)
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// start the TCP server on the same port as the UDP server
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fallbackTcpAddr := fmt.Sprintf("127.0.0.1:%s", fallbackPort)
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ts, fallbackTcpAddr, err := RunLocalTCPServer(t, fallbackTcpAddr, fallbackTCPHandler)
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wt.AssertNoErr(t, err)
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defer ts.Shutdown()
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t.Logf("Creating a WeaveDNS server instance, falling back to 127.0.0.1:%s", fallbackPort)
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config := &dns.ClientConfig{Servers: []string{"127.0.0.1"}, Port: fallbackPort}
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srv := NewDNSServer(config, zone, nil, port)
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defer srv.Stop()
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@@ -153,74 +196,78 @@ func TestTCPDNSServer(t *testing.T) {
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wt.AssertNoErr(t, err)
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time.Sleep(100 * time.Millisecond) // Allow sever goroutine to start
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// Create a regular UDP client and a TCP client
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t.Logf("Creating a UDP and a TCP client")
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uc := new(dns.Client)
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uc.UDPSize = UDPBufSize
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tc := new(dns.Client)
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tc.Net = "tcp"
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t.Logf("Creating DNS query message")
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m := new(dns.Msg)
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m.SetQuestion(localTestName, dns.TypeA)
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m.RecursionDesired = false
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m.RecursionDesired = true
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m.SetQuestion(nonLocalName, dns.TypeA)
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Debug.Printf("Using UDP for quering about %s", localTestName)
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r, _, err := uc.Exchange(m, dnsAddr)
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t.Logf("Checking the fallback server at %s returns a truncated response with UDP", fallbackUdpAddr)
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r, _, err := uc.Exchange(m, fallbackUdpAddr)
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t.Logf("Got response from fallback server (UDP) with %d answers", len(r.Answer))
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t.Logf("Response:\n%+v\n", r)
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wt.AssertNoErr(t, err)
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if len(r.Answer) > 1 { // TODO: remove this when we have proper support for multiple responses (zettio/weave#338)
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wt.AssertStatus(t, r.Rcode, dns.RcodeBadTrunc, "DNS response code")
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if len(r.Answer) == ansCount {
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wt.Fatalf(t, "%d answers received, but we expected less than that", len(r.Answer))
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}
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} else {
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Debug.Println("... multiple reponses not supported (yet)")
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wt.AssertStatus(t, r.Rcode, dns.RcodeSuccess, "DNS response code")
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}
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wt.AssertTrue(t, r.MsgHdr.Truncated, "DNS truncated reponse flag")
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wt.AssertNotEqualInt(t, len(r.Answer), numAnswers, "number of answers (UDP)")
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Debug.Println("Using TCP for the same query")
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tr, _, err := tc.Exchange(m, dnsAddr)
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t.Logf("Checking the WeaveDNS server at %s returns a truncated reponse with UDP", dnsAddr)
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r, _, err = uc.Exchange(m, dnsAddr)
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t.Logf("Got response from WeaveDNS (UDP) with %d answers", len(r.Answer))
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t.Logf("Response:\n%+v\n", r)
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wt.AssertNoErr(t, err)
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wt.AssertStatus(t, tr.Rcode, dns.RcodeSuccess, "DNS response code (TCP)")
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if len(r.Answer) > 1 { // TODO: remove this when we have proper support for multiple responses (zettio/weave#338)
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wt.AssertEqualInt(t, len(tr.Answer), ansCount, "Number of answers (TCP)")
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}
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wt.AssertType(t, tr.Answer[0], (*dns.A)(nil), "DNS record (TCP)") // assume they are all the same...
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wt.AssertTrue(t, r.MsgHdr.Truncated, "DNS truncated reponse flag")
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wt.AssertNotEqualInt(t, len(r.Answer), numAnswers, "number of answers (UDP)")
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t.Logf("Checking the WeaveDNS server at %s does not return a truncated reponse with TCP", dnsAddr)
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r, _, err = tc.Exchange(m, dnsAddr)
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t.Logf("Got response from WeaveDNS (TCP) with %d answers", len(r.Answer))
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t.Logf("Response:\n%+v\n", r)
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wt.AssertNoErr(t, err)
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wt.AssertFalse(t, r.MsgHdr.Truncated, "DNS truncated response flag")
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wt.AssertEqualInt(t, len(r.Answer), numAnswers, "number of answers (TCP)")
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}
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func fallbackHandler(w dns.ResponseWriter, req *dns.Msg) {
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m := new(dns.Msg)
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m.SetReply(req)
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if len(req.Question) == 1 {
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q := req.Question[0]
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if q.Name == "weave.works." && q.Qtype == dns.TypeMX {
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m.Answer = make([]dns.RR, 1)
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m.Answer[0] = &dns.MX{Hdr: dns.RR_Header{Name: m.Question[0].Name, Rrtype: dns.TypeMX, Class: dns.ClassINET, Ttl: 0}, Mx: "mail.weave.works."}
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} else if q.Name == "weave.works." && q.Qtype == dns.TypeANY {
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const N = 10
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m.Extra = make([]dns.RR, N)
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for i, _ := range m.Extra {
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m.Extra[i] = &dns.TXT{Hdr: dns.RR_Header{Name: m.Question[0].Name, Rrtype: dns.TypeTXT, Class: dns.ClassINET, Ttl: 0}, Txt: []string{"Lots and lots and lots and lots and lots and lots and lots and lots and lots of data"}}
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}
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} else if q.Name == testRDNSnonlocal && q.Qtype == dns.TypePTR {
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m.Answer = make([]dns.RR, 1)
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m.Answer[0] = &dns.PTR{Hdr: dns.RR_Header{Name: m.Question[0].Name, Rrtype: dns.TypePTR, Class: dns.ClassINET, Ttl: 0}, Ptr: "ns1.google.com."}
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} else if q.Name == testRDNSfail && q.Qtype == dns.TypePTR {
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m.Rcode = dns.RcodeNameError
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}
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}
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w.WriteMsg(m)
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}
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func RunLocalUDPServer(laddr string) (*dns.Server, string, error) {
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func RunLocalUDPServer(t *testing.T, laddr string, handler dns.HandlerFunc) (*dns.Server, string, error) {
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t.Logf("Starting fallback UDP server at %s", laddr)
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pc, err := net.ListenPacket("udp", laddr)
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if err != nil {
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return nil, "", err
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}
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server := &dns.Server{PacketConn: pc, Handler: dns.HandlerFunc(fallbackHandler)}
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server := &dns.Server{PacketConn: pc, Handler: handler}
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go func() {
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server.ActivateAndServe()
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pc.Close()
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}()
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t.Logf("Fallback UDP server listening at %s", pc.LocalAddr())
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return server, pc.LocalAddr().String(), nil
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}
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func RunLocalTCPServer(t *testing.T, laddr string, handler dns.HandlerFunc) (*dns.Server, string, error) {
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t.Logf("Starting fallback TCP server at %s", laddr)
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laddrTcp, err := net.ResolveTCPAddr("tcp", laddr)
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if err != nil {
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return nil, "", err
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}
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l, err := net.ListenTCP("tcp", laddrTcp)
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if err != nil {
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return nil, "", err
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}
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server := &dns.Server{Listener: l, Handler: handler}
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go func() {
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server.ActivateAndServe()
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l.Close()
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}()
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t.Logf("Fallback TCP server listening at %s", l.Addr().String())
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return server, l.Addr().String(), nil
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}
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@@ -7,6 +7,18 @@ import (
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"time"
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)
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func AssertTrue(t *testing.T, cond bool, desc string) {
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if !cond {
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Fatalf(t, "Expected %s to be true", desc)
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}
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}
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func AssertFalse(t *testing.T, cond bool, desc string) {
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if cond {
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Fatalf(t, "Expected %s to be false", desc)
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}
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}
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func AssertNoErr(t *testing.T, err error) {
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if err != nil {
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Fatalf(t, "Unexpected error: %s", err)
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@@ -25,6 +37,12 @@ func AssertEqualInt(t *testing.T, got, wanted int, desc string) {
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}
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}
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func AssertNotEqualInt(t *testing.T, got, wanted int, desc string) {
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if got == wanted {
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Fatalf(t, "Expected %s %d to be different to %d", desc, wanted, got)
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}
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}
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func AssertEqualString(t *testing.T, got, wanted string, desc string) {
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if got != wanted {
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Fatalf(t, "Expected %s '%s' but got '%s'", desc, wanted, got)
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