- Add testcase for refreshing expired error responses.

doc/Changelog

@@ -1,5 +1,6 @@
 9 February 2023: George
 	- Allow TTL refresh of expired error responses.
+	- Add testcase for refreshing expired error responses.
 
 9 February 2023: Wouter
 	- Fix to ignore entirely empty responses, and try at another authority.

testdata/serve_expired_cached_servfail_refresh.rpl

@@ -0,0 +1,145 @@
+; config options
+server:
+	module-config: "validator iterator"
+	qname-minimisation: "no"
+	minimal-responses: no
+	serve-expired: yes
+	serve-expired-reply-ttl: 123
+	log-servfail: yes
+	ede: yes
+	ede-serve-expired: yes
+
+
+stub-zone:
+	name: "example.com"
+	stub-addr: 1.2.3.4
+CONFIG_END
+
+SCENARIO_BEGIN Test serve-expired with client-timeout and a SERVFAIL upstream reply
+; Scenario overview:
+; - query for example.com. IN A
+; - answer from upstream is SERVFAIL; will be cached for NORR_TTL(5)
+; - check that the client gets the SERVFAIL; also cached
+; - query again right after the TTL expired
+; - cached SERVFAIL should be ignored and upstream queried
+; - answer from upstream is still SERVFAIL; the cached error response will be
+;   refreshed for another NORR_TTL(5)
+; - check that the client gets the SERVFAIL
+; - query again; the upstream now has the answer available
+; - check that we get the refreshed cached response instead
+
+; ns.example.com.
+RANGE_BEGIN 0 50
+	ADDRESS 1.2.3.4
+	; response to A query
+	ENTRY_BEGIN
+		MATCH opcode qtype qname
+		ADJUST copy_id
+		REPLY QR AA SERVFAIL
+		SECTION QUESTION
+			example.com. IN A
+	ENTRY_END
+RANGE_END
+
+; ns.example.com.
+RANGE_BEGIN 60 100
+	ADDRESS 1.2.3.4
+	ENTRY_BEGIN
+		MATCH opcode qtype qname
+		ADJUST copy_id
+		REPLY QR NOERROR
+		SECTION QUESTION
+			example.com. 10 IN NS
+		SECTION ANSWER
+			example.com. 10 IN NS ns.example.com.
+		SECTION ADDITIONAL
+			ns.example.com. 10 IN A 1.2.3.4
+	ENTRY_END
+
+	ENTRY_BEGIN
+		MATCH opcode qtype qname
+		ADJUST copy_id
+		REPLY QR NOERROR
+		SECTION QUESTION
+			example.com. IN A
+		SECTION ANSWER
+			example.com. 10 IN A 5.6.7.8
+		SECTION AUTHORITY
+			example.com. 10 IN NS ns.example.com.
+		SECTION ADDITIONAL
+			ns.example.com. 10 IN A 1.2.3.4
+	ENTRY_END
+RANGE_END
+
+; Query with RD flag
+STEP 0 QUERY
+ENTRY_BEGIN
+	REPLY RD
+	SECTION QUESTION
+		example.com. IN A
+ENTRY_END
+
+; Check that we get the SERVFAIL (will be cached)
+STEP 10 CHECK_ANSWER
+ENTRY_BEGIN
+	MATCH all
+	REPLY QR RD RA SERVFAIL
+	SECTION QUESTION
+		example.com. IN A
+ENTRY_END
+
+; Query again
+STEP 20 QUERY
+ENTRY_BEGIN
+	REPLY RD
+	SECTION QUESTION
+		example.com. IN A
+ENTRY_END
+
+; Check that we get the cached SERVFAIL
+STEP 30 CHECK_ANSWER
+ENTRY_BEGIN
+	MATCH all
+	REPLY QR RD RA SERVFAIL
+	SECTION QUESTION
+		example.com. IN A
+ENTRY_END
+
+; Wait for the SERVFAIL to expire
+STEP 31 TIME_PASSES ELAPSE 6
+
+; Query again
+STEP 40 QUERY
+ENTRY_BEGIN
+	REPLY RD
+	SECTION QUESTION
+		example.com. IN A
+ENTRY_END
+
+; Check that we get the SERVFAIL (will be refreshed)
+STEP 50 CHECK_ANSWER
+ENTRY_BEGIN
+	MATCH all
+	REPLY QR RD RA SERVFAIL
+	SECTION QUESTION
+		example.com. IN A
+ENTRY_END
+
+; Query again, upstream has the real answer available
+STEP 60 QUERY
+ENTRY_BEGIN
+	REPLY RD
+	SECTION QUESTION
+		example.com. IN A
+ENTRY_END
+
+; Check that we get the refreshed cached SERVFAIL
+STEP 70 CHECK_ANSWER
+ENTRY_BEGIN
+	MATCH all
+	REPLY QR RD RA SERVFAIL
+	SECTION QUESTION
+		example.com. IN A
+ENTRY_END
+
+SCENARIO_END