- Fix #558: failed prefetch lookup does not remove cached response

  but delays next prefetch (in lieu of caching a SERVFAIL).

git-svn-id: file:///svn/unbound/trunk@3111 be551aaa-1e26-0410-a405-d3ace91eadb9

diff --git a/doc/Changelog b/doc/Changelog
index f765e93220bae8dfc5922784a85acec8ba2796a9..e4f20f3a9deb821c868c1050433f8936bfa9e8ca 100644 (file)
--- a/doc/Changelog
+++ b/doc/Changelog
@@ -10,6 +10,8 @@
          (for NetworkManager integration.)
        - Fix #554: use unsigned long to print 64bit statistics counters on
          64bit systems.
+       - Fix #558: failed prefetch lookup does not remove cached response
+         but delays next prefetch (in lieu of caching a SERVFAIL).
 
 8 April 2014: Wouter
        - Fix #574: make test fails on Ubuntu 14.04.  Disabled remote-control

diff --git a/iterator/iterator.c b/iterator/iterator.c
index 87fac81f38c64598cbd68f11028628902c377766..f240f503489ef28d3fed13e9641b6addf400c2a3 100644 (file)
--- a/iterator/iterator.c
+++ b/iterator/iterator.c
@@ -253,6 +253,14 @@ error_response_cache(struct module_qstate* qstate, int id, int rcode)
 {
        /* store in cache */
        struct reply_info err;
+       if(qstate->prefetch_leeway > NORR_TTL) {
+               verbose(VERB_ALGO, "error response for prefetch in cache");
+               /* attempt to adjust the cache entry prefetch */
+               if(dns_cache_prefetch_adjust(qstate->env, &qstate->qinfo,
+                       NORR_TTL))
+                       return error_response(qstate, id, rcode);
+               /* if that fails (not in cache), fall through to store err */
+       }
        memset(&err, 0, sizeof(err));
        err.flags = (uint16_t)(BIT_QR | BIT_RA);
        FLAGS_SET_RCODE(err.flags, rcode);

diff --git a/services/cache/dns.c b/services/cache/dns.c
index f2a04a227cb907cdc2e40cce217fb03c9f239a05..c663b8e8b9a2aaccda0d60211c91958e75acb01f 100644 (file)
--- a/services/cache/dns.c
+++ b/services/cache/dns.c
@@ -795,3 +795,22 @@ dns_cache_store(struct module_env* env, struct query_info* msgqinf,
        }
        return 1;
 }
+
+int 
+dns_cache_prefetch_adjust(struct module_env* env, struct query_info* qinfo,
+        time_t adjust)
+{
+       struct msgreply_entry* msg;
+       msg = msg_cache_lookup(env, qinfo->qname, qinfo->qname_len,
+               qinfo->qtype, qinfo->qclass, *env->now, 1);
+       if(msg) {
+               struct reply_info* rep = (struct reply_info*)msg->entry.data;
+               if(rep) {
+                       rep->prefetch_ttl += adjust;
+                       lock_rw_unlock(&msg->entry.lock);
+                       return 1;
+               }
+               lock_rw_unlock(&msg->entry.lock);
+       }
+       return 0;
+}

diff --git a/services/cache/dns.h b/services/cache/dns.h
index a7a6190cffba1634aa25655c92bc18689e58ac5e..05a3e62965430ea3fde6deacd7779e40e22616ce 100644 (file)
--- a/services/cache/dns.h
+++ b/services/cache/dns.h
@@ -179,4 +179,16 @@ struct dns_msg* dns_msg_create(uint8_t* qname, size_t qnamelen, uint16_t qtype,
 int dns_msg_authadd(struct dns_msg* msg, struct regional* region, 
        struct ub_packed_rrset_key* rrset, time_t now);
 
+/**
+ * Adjust the prefetch_ttl for a cached message.  This adds a value to the
+ * prefetch ttl - postponing the time when it will be prefetched for future
+ * incoming queries.
+ * @param env: module environment with caches and time.
+ * @param qinfo: query info for the query that needs adjustment.
+ * @param adjust: time in seconds to add to the prefetch_leeway.
+ * @return false if not in cache. true if added.
+ */
+int dns_cache_prefetch_adjust(struct module_env* env, struct query_info* qinfo,
+        time_t adjust);
+
 #endif /* SERVICES_CACHE_DNS_H */

diff --git a/testdata/iter_prefetch_fail.rpl b/testdata/iter_prefetch_fail.rpl
new file mode 100644 (file)
index 0000000..2f7f994
--- /dev/null
+++ b/testdata/iter_prefetch_fail.rpl
@@ -0,0 +1,393 @@
+; config options
+server:
+       target-fetch-policy: "0 0 0 0 0"
+       prefetch: "yes"
+
+stub-zone:
+       name: "."
+       stub-addr: 193.0.14.129         # K.ROOT-SERVERS.NET.
+CONFIG_END
+
+SCENARIO_BEGIN Test resolver prefetch where it fails to fetch
+
+; K.ROOT-SERVERS.NET.
+RANGE_BEGIN 0 200
+       ADDRESS 193.0.14.129 
+ENTRY_BEGIN
+MATCH opcode qtype qname
+ADJUST copy_id
+REPLY QR NOERROR
+SECTION QUESTION
+. IN NS
+SECTION ANSWER
+. IN NS        K.ROOT-SERVERS.NET.
+SECTION ADDITIONAL
+K.ROOT-SERVERS.NET.    IN      A       193.0.14.129
+ENTRY_END
+
+ENTRY_BEGIN
+MATCH opcode subdomain
+ADJUST copy_id copy_query
+REPLY QR NOERROR
+SECTION QUESTION
+com. IN NS
+SECTION AUTHORITY
+com.   IN NS   a.gtld-servers.net.
+SECTION ADDITIONAL
+a.gtld-servers.net.    IN      A       192.5.6.30
+ENTRY_END
+RANGE_END
+
+; a.gtld-servers.net.
+RANGE_BEGIN 0 200
+       ADDRESS 192.5.6.30
+ENTRY_BEGIN
+MATCH opcode qtype qname
+ADJUST copy_id
+REPLY QR NOERROR
+SECTION QUESTION
+com. IN NS
+SECTION ANSWER
+com.   IN NS   a.gtld-servers.net.
+SECTION ADDITIONAL
+a.gtld-servers.net.    IN      A       192.5.6.30
+ENTRY_END
+
+ENTRY_BEGIN
+MATCH opcode subdomain
+ADJUST copy_id copy_query
+REPLY QR NOERROR
+SECTION QUESTION
+example.com. IN NS
+SECTION AUTHORITY
+example.com.   IN NS   ns.example.com.
+SECTION ADDITIONAL
+ns.example.com.                IN      A       1.2.3.4
+ENTRY_END
+RANGE_END
+
+; ns.example.com.
+RANGE_BEGIN 0 40
+       ADDRESS 1.2.3.4
+ENTRY_BEGIN
+MATCH opcode qtype qname
+ADJUST copy_id
+REPLY QR NOERROR
+SECTION QUESTION
+example.com. IN NS
+SECTION ANSWER
+example.com.   IN NS   ns.example.com.
+SECTION ADDITIONAL
+ns.example.com.                IN      A       1.2.3.4
+ENTRY_END
+
+ENTRY_BEGIN
+MATCH opcode qtype qname
+ADJUST copy_id
+REPLY QR NOERROR
+SECTION QUESTION
+ns.example.com. IN AAAA
+SECTION ANSWER
+SECTION AUTHORITY
+example.com.   IN SOA  ns.example.com. hostmaster.example.com. 1 2 3 4 5
+ENTRY_END
+
+ENTRY_BEGIN
+MATCH opcode qtype qname
+ADJUST copy_id
+REPLY QR NOERROR
+SECTION QUESTION
+ns.example.com. IN A
+SECTION ANSWER
+ns.example.com.                IN      A       1.2.3.4
+ENTRY_END
+
+ENTRY_BEGIN
+MATCH opcode qtype qname
+ADJUST copy_id
+REPLY QR NOERROR
+SECTION QUESTION
+www.example.com. IN A
+SECTION ANSWER
+www.example.com. 3600 IN A     10.20.30.40
+SECTION AUTHORITY
+example.com.   3600 IN NS      ns.example.com.
+SECTION ADDITIONAL
+ns.example.com.        3600    IN      A       1.2.3.4
+ENTRY_END
+RANGE_END
+
+; ns.example.com.
+RANGE_BEGIN 50 100
+       ADDRESS 1.2.3.4
+ENTRY_BEGIN
+MATCH opcode qtype qname
+ADJUST copy_id
+REPLY QR NOERROR
+SECTION QUESTION
+example.com. IN NS
+SECTION ANSWER
+example.com.   IN NS   ns.example.com.
+SECTION ADDITIONAL
+ns.example.com.                IN      A       1.2.3.4
+ENTRY_END
+
+ENTRY_BEGIN
+MATCH opcode qtype qname
+ADJUST copy_id
+REPLY QR NOERROR
+SECTION QUESTION
+ns.example.com. IN A
+SECTION ANSWER
+ns.example.com.                IN      A       1.2.3.4
+ENTRY_END
+
+ENTRY_BEGIN
+MATCH opcode qtype qname
+ADJUST copy_id
+REPLY QR NOERROR
+SECTION QUESTION
+ns.example.com. IN AAAA
+SECTION ANSWER
+SECTION AUTHORITY
+example.com.   IN SOA  ns.example.com. hostmaster.example.com. 1 2 3 4 5
+ENTRY_END
+
+ENTRY_BEGIN
+MATCH opcode qtype qname
+ADJUST copy_id
+REPLY QR AA SERVFAIL
+SECTION QUESTION
+www.example.com. IN A
+;SECTION ANSWER
+;www.example.com. 3600 IN A    10.20.30.40
+;SECTION AUTHORITY
+;example.com.  3600 IN NS      ns.example.com.
+;SECTION ADDITIONAL
+;ns.example.com.       3600    IN      A       1.2.3.4
+ENTRY_END
+RANGE_END
+
+; note ns.example.com range for steps 100 - 160 is not entered
+; no queries should be sent there
+
+; ns.example.com.
+RANGE_BEGIN 160 200
+       ADDRESS 1.2.3.4
+ENTRY_BEGIN
+MATCH opcode qtype qname
+ADJUST copy_id
+REPLY QR NOERROR
+SECTION QUESTION
+example.com. IN NS
+SECTION ANSWER
+example.com.   IN NS   ns.example.com.
+SECTION ADDITIONAL
+ns.example.com.                IN      A       1.2.3.4
+ENTRY_END
+
+ENTRY_BEGIN
+MATCH opcode qtype qname
+ADJUST copy_id
+REPLY QR NOERROR
+SECTION QUESTION
+ns.example.com. IN AAAA
+SECTION ANSWER
+SECTION AUTHORITY
+example.com.   IN SOA  ns.example.com. hostmaster.example.com. 1 2 3 4 5
+ENTRY_END
+
+ENTRY_BEGIN
+MATCH opcode qtype qname
+ADJUST copy_id
+REPLY QR NOERROR
+SECTION QUESTION
+ns.example.com. IN A
+SECTION ANSWER
+ns.example.com.                IN      A       1.2.3.4
+ENTRY_END
+
+ENTRY_BEGIN
+MATCH opcode qtype qname
+ADJUST copy_id
+REPLY QR NOERROR
+SECTION QUESTION
+www.example.com. IN A
+SECTION ANSWER
+www.example.com. 3600 IN A     10.20.30.40
+SECTION AUTHORITY
+example.com.   3600 IN NS      ns.example.com.
+SECTION ADDITIONAL
+ns.example.com.        3600    IN      A       1.2.3.4
+ENTRY_END
+RANGE_END
+
+STEP 1 QUERY
+ENTRY_BEGIN
+REPLY RD
+SECTION QUESTION
+www.example.com. IN A
+ENTRY_END
+
+; recursion happens here.
+STEP 10 CHECK_ANSWER
+ENTRY_BEGIN
+MATCH all ttl
+REPLY QR RD RA NOERROR
+SECTION QUESTION
+www.example.com. IN A
+SECTION ANSWER
+www.example.com. 3600 IN A     10.20.30.40
+SECTION AUTHORITY
+example.com.   3600 IN NS      ns.example.com.
+SECTION ADDITIONAL
+ns.example.com.        3600    IN      A       1.2.3.4
+ENTRY_END
+
+; after 1800 secs still the cached answer
+STEP 20 TIME_PASSES ELAPSE 1800
+
+STEP 30 QUERY
+ENTRY_BEGIN
+REPLY RD
+SECTION QUESTION
+www.example.com. IN A
+ENTRY_END
+; recursion happens here.
+STEP 40 CHECK_ANSWER
+ENTRY_BEGIN
+MATCH all ttl
+REPLY QR RD RA NOERROR
+SECTION QUESTION
+www.example.com. IN A
+SECTION ANSWER
+www.example.com. 1800 IN A     10.20.30.40
+SECTION AUTHORITY
+example.com.   1800 IN NS      ns.example.com.
+SECTION ADDITIONAL
+ns.example.com.        1800    IN      A       1.2.3.4
+ENTRY_END
+
+; after 1440 we are 360 seconds before the expiry
+; (the authority changes behind the scenes to detect new lookup)
+STEP 50 TIME_PASSES ELAPSE 1440
+
+STEP 60 QUERY
+ENTRY_BEGIN
+REPLY RD
+SECTION QUESTION
+www.example.com. IN A
+ENTRY_END
+; recursion happens here.
+STEP 70 CHECK_ANSWER
+ENTRY_BEGIN
+MATCH all ttl
+REPLY QR RD RA NOERROR
+SECTION QUESTION
+www.example.com. IN A
+SECTION ANSWER
+www.example.com. 360 IN A      10.20.30.40
+SECTION AUTHORITY
+example.com.   360 IN NS       ns.example.com.
+SECTION ADDITIONAL
+ns.example.com.        360     IN      A       1.2.3.4
+ENTRY_END
+STEP 80 TRAFFIC
+; let traffic flow for prefetch to happen
+
+; above a cache reply with 10% of the original TTL
+; but the actual cache could have been updated, try to get that
+STEP 120 QUERY
+ENTRY_BEGIN
+REPLY RD
+SECTION QUESTION
+www.example.com. IN A
+ENTRY_END
+; recursion happens here.
+STEP 130 CHECK_ANSWER
+ENTRY_BEGIN
+MATCH all ttl
+REPLY QR RD RA NOERROR
+SECTION QUESTION
+www.example.com. IN A
+SECTION ANSWER
+www.example.com. 360 IN A      10.20.30.40
+SECTION AUTHORITY
+example.com.   360 IN NS       ns.example.com.
+SECTION ADDITIONAL
+; this is picked up from the parent (because this simulation has the
+; parent respond with servfail, not actually timeout)
+ns.example.com.        3600    IN      A       1.2.3.4
+ENTRY_END
+
+; another query to see if there is another lookup towards the authority
+; the server should not send too many queries towards the authority
+STEP 140 QUERY
+ENTRY_BEGIN
+REPLY RD
+SECTION QUESTION
+www.example.com. IN A
+ENTRY_END
+; recursion happens here.
+STEP 150 CHECK_ANSWER
+ENTRY_BEGIN
+MATCH all ttl
+REPLY QR RD RA NOERROR
+SECTION QUESTION
+www.example.com. IN A
+SECTION ANSWER
+www.example.com. 360 IN A      10.20.30.40
+SECTION AUTHORITY
+example.com.   360 IN NS       ns.example.com.
+SECTION ADDITIONAL
+ns.example.com.        3600    IN      A       1.2.3.4
+ENTRY_END
+
+; some time later another query, and now it is fine to bother the authority
+; with another lookup attempt.
+STEP 160 TIME_PASSES ELAPSE 30
+; so we are now 330 seconds before expiry.
+STEP 170 QUERY
+ENTRY_BEGIN
+REPLY RD
+SECTION QUESTION
+www.example.com. IN A
+ENTRY_END
+; recursion happens here.
+STEP 180 CHECK_ANSWER
+ENTRY_BEGIN
+MATCH all ttl
+REPLY QR RD RA NOERROR
+SECTION QUESTION
+www.example.com. IN A
+SECTION ANSWER
+www.example.com. 330 IN A      10.20.30.40
+SECTION AUTHORITY
+example.com.   330 IN NS       ns.example.com.
+SECTION ADDITIONAL
+ns.example.com.        3570    IN      A       1.2.3.4
+ENTRY_END
+; now the just-looked-up entry
+STEP 190 QUERY
+ENTRY_BEGIN
+REPLY RD
+SECTION QUESTION
+www.example.com. IN A
+ENTRY_END
+; recursion happens here.
+STEP 200 CHECK_ANSWER
+ENTRY_BEGIN
+MATCH all ttl
+REPLY QR RD RA NOERROR
+SECTION QUESTION
+www.example.com. IN A
+SECTION ANSWER
+www.example.com. 3600 IN A     10.20.30.40
+SECTION AUTHORITY
+example.com.   3600 IN NS      ns.example.com.
+SECTION ADDITIONAL
+ns.example.com.        3570    IN      A       1.2.3.4
+ENTRY_END
+
+
+SCENARIO_END