fix(webconnectivitylte): handle domains w/o A/AAAA records (#1473)

This diff improves webconnectivitylte and minipipeline to correctly handle the case where a website has no configured IP addresses but the domain for the website exists. When this happens, the TH returns no error but an empty list of resolved addresses for historical reasons, while the probe fails with the `"dns_no_answer"` error. We need to intercept and correctly handle this scenario both for the ordinary analysis and the classic analysis. Let's also add QA test cases to make sure we don't regress. Part of ooni/probe#2652.
ooni · Jan 24, 2024 · 2d9d7ba · 2d9d7ba
1 parent 2cc9231
commit 2d9d7ba
Show file tree

Hide file tree

Showing 9 changed files with 1,016 additions and 5 deletions.
diff --git a/internal/experiment/webconnectivitylte/analysisclassic.go b/internal/experiment/webconnectivitylte/analysisclassic.go
@@ -373,7 +373,17 @@ func analysisClassicComputeBlockingAccessible(woa *minipipeline.WebAnalysis, tk
 				return
 			}
 
-			// 5.3. Handle the case where just the probe failed.
+			// 5.3. When the probe says dns_no_answer the control would otherwise say that
+			// we have resolved zero IP addresses for historical reasons. In such a case,
+			// let's pretend that also the control returned dns_no_answer.
+			if entry.Failure.Unwrap() == netxlite.FailureDNSNoAnswer &&
+				!entry.ControlDNSResolvedAddrs.IsNone() &&
+				entry.ControlDNSResolvedAddrs.Unwrap().Len() <= 0 {
+				tk.setWebsiteDown()
+				return
+			}
+
+			// 5.4. Handle the case where just the probe failed.
 			tk.setBlockingString("dns")
 			tk.setHTTPExperimentFailure(entry.Failure)
 			return
@@ -406,9 +416,6 @@ func analysisClassicComputeBlockingAccessible(woa *minipipeline.WebAnalysis, tk
 			tk.setWebsiteDown()
 			return
 		}
-
-		// TODO(bassosimone): we should handle the case where a domain
-		// exists but there aren't IP addresses for it.
 	}
 }
 

diff --git a/internal/experiment/webconnectivityqa/testcase.go b/internal/experiment/webconnectivityqa/testcase.go
@@ -88,6 +88,7 @@ func AllTestCases() []*TestCase {
 		tlsBlockingConnectionResetWithInconsistentDNS(),
 
 		websiteDownNXDOMAIN(),
+		websiteDownNoAddrs(),
 		websiteDownTCPConnect(),
 	}
 }
diff --git a/internal/experiment/webconnectivityqa/websitedown.go b/internal/experiment/webconnectivityqa/websitedown.go
@@ -1,5 +1,7 @@
 package webconnectivityqa
 
+import "github.com/ooni/probe-cli/v3/internal/netemx"
+
 // websiteDownNXDOMAIN describes the test case where the website domain
 // is NXDOMAIN according to the TH and the probe.
 func websiteDownNXDOMAIN() *TestCase {
@@ -60,3 +62,29 @@ func websiteDownTCPConnect() *TestCase {
 		},
 	}
 }
+
+// websiteDownNoAddrs describes the test case where the website domain
+// does not return any address according to the TH and the probe.
+func websiteDownNoAddrs() *TestCase {
+	return &TestCase{
+		Name:  "websiteDownNoAddrs",
+		Flags: TestCaseFlagNoV04,
+		Input: "http://www.example.com/",
+		Configure: func(env *netemx.QAEnv) {
+
+			// reconfigure with only CNAME but no addresses and do this
+			// for all the resolvers of the kingdom
+			env.AddRecordToAllResolvers("www.example.com", "web01.example.com" /* No addrs */)
+
+		},
+		ExpectErr: false,
+		ExpectTestKeys: &testKeys{
+			DNSExperimentFailure: "dns_no_answer",
+			DNSConsistency:       "consistent",
+			XBlockingFlags:       0,
+			XNullNullFlags:       1, // AnalysisFlagNullNullExpectedDNSLookupFailure
+			Accessible:           false,
+			Blocking:             false,
+		},
+	}
+}
diff --git a/internal/minipipeline/analysis.go b/internal/minipipeline/analysis.go
@@ -4,6 +4,7 @@ import (
 	"sort"
 
 	"github.com/ooni/probe-cli/v3/internal/model"
+	"github.com/ooni/probe-cli/v3/internal/netxlite"
 	"github.com/ooni/probe-cli/v3/internal/optional"
 	"github.com/ooni/probe-cli/v3/internal/runtimex"
 )
@@ -449,7 +450,17 @@ func (wa *WebAnalysis) dnsComputeFailureMetrics(c *WebObservationsContainer) {
 		}
 
 		// handle the case where only the probe failed
-		if obs.DNSLookupFailure.Unwrap() != "" {
+		if failure := obs.DNSLookupFailure.Unwrap(); failure != "" {
+			// When the probe says dns_no_answer the control would otherwise say that
+			// we have resolved zero IP addresses for historical reasons. In such a case,
+			// let's pretend that also the control returned dns_no_answer.
+			if failure == netxlite.FailureDNSNoAnswer {
+				if !obs.ControlDNSResolvedAddrs.IsNone() && obs.ControlDNSResolvedAddrs.Unwrap().Len() <= 0 {
+					wa.DNSLookupExpectedFailure.Add(obs.DNSTransactionID.Unwrap())
+					continue
+				}
+				// fallthrough
+			}
 			wa.DNSLookupUnexpectedFailure.Add(obs.DNSTransactionID.Unwrap())
 			continue
 		}

diff --git a/internal/minipipeline/testdata/webconnectivity/generated/websiteDownNoAddrs/analysis.json b/internal/minipipeline/testdata/webconnectivity/generated/websiteDownNoAddrs/analysis.json
@@ -0,0 +1,261 @@
+{
+  "ControlExpectations": {
+    "DNSAddresses": [],
+    "FinalResponseFailure": "dns_lookup_error"
+  },
+  "DNSLookupSuccess": [],
+  "DNSLookupSuccessWithInvalidAddresses": [],
+  "DNSLookupSuccessWithValidAddress": [],
+  "DNSLookupSuccessWithBogonAddresses": [],
+  "DNSLookupSuccessWithInvalidAddressesClassic": [],
+  "DNSLookupSuccessWithValidAddressClassic": [],
+  "DNSLookupUnexpectedFailure": [],
+  "DNSLookupUnexplainedFailure": [],
+  "DNSExperimentFailure": "dns_no_answer",
+  "DNSLookupExpectedFailure": [
+    2,
+    3
+  ],
+  "DNSLookupExpectedSuccess": [],
+  "TCPConnectExpectedFailure": [],
+  "TCPConnectUnexpectedFailure": [],
+  "TCPConnectUnexpectedFailureDuringWebFetch": [],
+  "TCPConnectUnexpectedFailureDuringConnectivityCheck": [],
+  "TCPConnectUnexplainedFailure": [],
+  "TCPConnectUnexplainedFailureDuringWebFetch": [],
+  "TCPConnectUnexplainedFailureDuringConnectivityCheck": [],
+  "TLSHandshakeExpectedFailure": [],
+  "TLSHandshakeUnexpectedFailure": [],
+  "TLSHandshakeUnexpectedFailureDuringWebFetch": [],
+  "TLSHandshakeUnexpectedFailureDuringConnectivityCheck": [],
+  "TLSHandshakeUnexplainedFailure": [],
+  "TLSHandshakeUnexplainedFailureDuringWebFetch": [],
+  "TLSHandshakeUnexplainedFailureDuringConnectivityCheck": [],
+  "HTTPRoundTripUnexpectedFailure": [],
+  "HTTPRoundTripUnexplainedFailure": [],
+  "HTTPFinalResponseSuccessTLSWithoutControl": null,
+  "HTTPFinalResponseSuccessTLSWithControl": null,
+  "HTTPFinalResponseSuccessTCPWithoutControl": null,
+  "HTTPFinalResponseSuccessTCPWithControl": null,
+  "HTTPFinalResponseDiffBodyProportionFactor": null,
+  "HTTPFinalResponseDiffStatusCodeMatch": null,
+  "HTTPFinalResponseDiffTitleDifferentLongWords": null,
+  "HTTPFinalResponseDiffUncommonHeadersIntersection": null,
+  "Linear": [
+    {
+      "TagDepth": 0,
+      "Type": 0,
+      "Failure": "dns_no_answer",
+      "TransactionID": 3,
+      "TagFetchBody": null,
+      "DNSTransactionID": 3,
+      "DNSDomain": "www.example.com",
+      "DNSLookupFailure": "dns_no_answer",
+      "DNSQueryType": "A",
+      "DNSEngine": "udp",
+      "DNSResolvedAddrs": null,
+      "IPAddressOrigin": null,
+      "IPAddress": null,
+      "IPAddressASN": null,
+      "IPAddressBogon": null,
+      "EndpointTransactionID": null,
+      "EndpointProto": null,
+      "EndpointPort": null,
+      "EndpointAddress": null,
+      "TCPConnectFailure": null,
+      "TLSHandshakeFailure": null,
+      "TLSServerName": null,
+      "HTTPRequestURL": null,
+      "HTTPFailure": null,
+      "HTTPResponseStatusCode": null,
+      "HTTPResponseBodyLength": null,
+      "HTTPResponseBodyIsTruncated": null,
+      "HTTPResponseHeadersKeys": null,
+      "HTTPResponseLocation": null,
+      "HTTPResponseTitle": null,
+      "HTTPResponseIsFinal": null,
+      "ControlDNSDomain": "www.example.com",
+      "ControlDNSLookupFailure": "",
+      "ControlDNSResolvedAddrs": [],
+      "ControlTCPConnectFailure": null,
+      "ControlTLSHandshakeFailure": null,
+      "ControlHTTPFailure": "dns_lookup_error",
+      "ControlHTTPResponseStatusCode": null,
+      "ControlHTTPResponseBodyLength": null,
+      "ControlHTTPResponseHeadersKeys": null,
+      "ControlHTTPResponseTitle": null
+    },
+    {
+      "TagDepth": 0,
+      "Type": 0,
+      "Failure": "dns_no_answer",
+      "TransactionID": 3,
+      "TagFetchBody": null,
+      "DNSTransactionID": 3,
+      "DNSDomain": "www.example.com",
+      "DNSLookupFailure": "dns_no_answer",
+      "DNSQueryType": "AAAA",
+      "DNSEngine": "udp",
+      "DNSResolvedAddrs": null,
+      "IPAddressOrigin": null,
+      "IPAddress": null,
+      "IPAddressASN": null,
+      "IPAddressBogon": null,
+      "EndpointTransactionID": null,
+      "EndpointProto": null,
+      "EndpointPort": null,
+      "EndpointAddress": null,
+      "TCPConnectFailure": null,
+      "TLSHandshakeFailure": null,
+      "TLSServerName": null,
+      "HTTPRequestURL": null,
+      "HTTPFailure": null,
+      "HTTPResponseStatusCode": null,
+      "HTTPResponseBodyLength": null,
+      "HTTPResponseBodyIsTruncated": null,
+      "HTTPResponseHeadersKeys": null,
+      "HTTPResponseLocation": null,
+      "HTTPResponseTitle": null,
+      "HTTPResponseIsFinal": null,
+      "ControlDNSDomain": "www.example.com",
+      "ControlDNSLookupFailure": "",
+      "ControlDNSResolvedAddrs": [],
+      "ControlTCPConnectFailure": null,
+      "ControlTLSHandshakeFailure": null,
+      "ControlHTTPFailure": "dns_lookup_error",
+      "ControlHTTPResponseStatusCode": null,
+      "ControlHTTPResponseBodyLength": null,
+      "ControlHTTPResponseHeadersKeys": null,
+      "ControlHTTPResponseTitle": null
+    },
+    {
+      "TagDepth": 0,
+      "Type": 0,
+      "Failure": "dns_no_answer",
+      "TransactionID": 2,
+      "TagFetchBody": null,
+      "DNSTransactionID": 2,
+      "DNSDomain": "www.example.com",
+      "DNSLookupFailure": "dns_no_answer",
+      "DNSQueryType": "ANY",
+      "DNSEngine": "getaddrinfo",
+      "DNSResolvedAddrs": null,
+      "IPAddressOrigin": null,
+      "IPAddress": null,
+      "IPAddressASN": null,
+      "IPAddressBogon": null,
+      "EndpointTransactionID": null,
+      "EndpointProto": null,
+      "EndpointPort": null,
+      "EndpointAddress": null,
+      "TCPConnectFailure": null,
+      "TLSHandshakeFailure": null,
+      "TLSServerName": null,
+      "HTTPRequestURL": null,
+      "HTTPFailure": null,
+      "HTTPResponseStatusCode": null,
+      "HTTPResponseBodyLength": null,
+      "HTTPResponseBodyIsTruncated": null,
+      "HTTPResponseHeadersKeys": null,
+      "HTTPResponseLocation": null,
+      "HTTPResponseTitle": null,
+      "HTTPResponseIsFinal": null,
+      "ControlDNSDomain": "www.example.com",
+      "ControlDNSLookupFailure": "",
+      "ControlDNSResolvedAddrs": [],
+      "ControlTCPConnectFailure": null,
+      "ControlTLSHandshakeFailure": null,
+      "ControlHTTPFailure": "dns_lookup_error",
+      "ControlHTTPResponseStatusCode": null,
+      "ControlHTTPResponseBodyLength": null,
+      "ControlHTTPResponseHeadersKeys": null,
+      "ControlHTTPResponseTitle": null
+    },
+    {
+      "TagDepth": 0,
+      "Type": 0,
+      "Failure": "dns_nxdomain_error",
+      "TransactionID": 1,
+      "TagFetchBody": null,
+      "DNSTransactionID": 1,
+      "DNSDomain": "www.example.com",
+      "DNSLookupFailure": "dns_nxdomain_error",
+      "DNSQueryType": "AAAA",
+      "DNSEngine": "doh",
+      "DNSResolvedAddrs": null,
+      "IPAddressOrigin": null,
+      "IPAddress": null,
+      "IPAddressASN": null,
+      "IPAddressBogon": null,
+      "EndpointTransactionID": null,
+      "EndpointProto": null,
+      "EndpointPort": null,
+      "EndpointAddress": null,
+      "TCPConnectFailure": null,
+      "TLSHandshakeFailure": null,
+      "TLSServerName": null,
+      "HTTPRequestURL": null,
+      "HTTPFailure": null,
+      "HTTPResponseStatusCode": null,
+      "HTTPResponseBodyLength": null,
+      "HTTPResponseBodyIsTruncated": null,
+      "HTTPResponseHeadersKeys": null,
+      "HTTPResponseLocation": null,
+      "HTTPResponseTitle": null,
+      "HTTPResponseIsFinal": null,
+      "ControlDNSDomain": "www.example.com",
+      "ControlDNSLookupFailure": "",
+      "ControlDNSResolvedAddrs": [],
+      "ControlTCPConnectFailure": null,
+      "ControlTLSHandshakeFailure": null,
+      "ControlHTTPFailure": "dns_lookup_error",
+      "ControlHTTPResponseStatusCode": null,
+      "ControlHTTPResponseBodyLength": null,
+      "ControlHTTPResponseHeadersKeys": null,
+      "ControlHTTPResponseTitle": null
+    },
+    {
+      "TagDepth": 0,
+      "Type": 0,
+      "Failure": "dns_nxdomain_error",
+      "TransactionID": 1,
+      "TagFetchBody": null,
+      "DNSTransactionID": 1,
+      "DNSDomain": "www.example.com",
+      "DNSLookupFailure": "dns_nxdomain_error",
+      "DNSQueryType": "A",
+      "DNSEngine": "doh",
+      "DNSResolvedAddrs": null,
+      "IPAddressOrigin": null,
+      "IPAddress": null,
+      "IPAddressASN": null,
+      "IPAddressBogon": null,
+      "EndpointTransactionID": null,
+      "EndpointProto": null,
+      "EndpointPort": null,
+      "EndpointAddress": null,
+      "TCPConnectFailure": null,
+      "TLSHandshakeFailure": null,
+      "TLSServerName": null,
+      "HTTPRequestURL": null,
+      "HTTPFailure": null,
+      "HTTPResponseStatusCode": null,
+      "HTTPResponseBodyLength": null,
+      "HTTPResponseBodyIsTruncated": null,
+      "HTTPResponseHeadersKeys": null,
+      "HTTPResponseLocation": null,
+      "HTTPResponseTitle": null,
+      "HTTPResponseIsFinal": null,
+      "ControlDNSDomain": "www.example.com",
+      "ControlDNSLookupFailure": "",
+      "ControlDNSResolvedAddrs": [],
+      "ControlTCPConnectFailure": null,
+      "ControlTLSHandshakeFailure": null,
+      "ControlHTTPFailure": "dns_lookup_error",
+      "ControlHTTPResponseStatusCode": null,
+      "ControlHTTPResponseBodyLength": null,
+      "ControlHTTPResponseHeadersKeys": null,
+      "ControlHTTPResponseTitle": null
+    }
+  ]
+}