Cache for mDNS records

net/dns/mdns_cache_unittest.cc

+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/bind.h"
+#include "net/dns/dns_response.h"
+#include "net/dns/dns_test_util.h"
+#include "net/dns/mdns_cache.h"
+#include "net/dns/record_parsed.h"
+#include "net/dns/record_rdata.h"
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+using ::testing::Return;
+using ::testing::StrictMock;
+
+namespace net {
+
+static const uint8 kTestResponsesDifferentAnswers[] = {
+  // Answer 1
+  // ghs.l.google.com in DNS format.
+  0x03, 'g', 'h', 's',
+  0x01, 'l',
+  0x06, 'g', 'o', 'o', 'g', 'l', 'e',
+  0x03, 'c', 'o', 'm',
+  0x00,
+  0x00, 0x01,         // TYPE is A.
+  0x00, 0x01,         // CLASS is IN.
+  0x00, 0x00,         // TTL (4 bytes) is 53 seconds.
+  0x00, 0x35,
+  0x00, 0x04,         // RDLENGTH is 4 bytes.
+  0x4a, 0x7d,         // RDATA is the IP: 74.125.95.121
+  0x5f, 0x79,
+
+  // Answer 2
+  // Pointer to answer 1
+  0xc0, 0x00,
+  0x00, 0x01,         // TYPE is A.
+  0x00, 0x01,         // CLASS is IN.
+  0x00, 0x00,         // TTL (4 bytes) is 53 seconds.
+  0x00, 0x35,
+  0x00, 0x04,         // RDLENGTH is 4 bytes.
+  0x4a, 0x7d,         // RDATA is the IP: 74.125.95.122
+  0x5f, 0x80,
+};
+
+static const uint8 kTestResponsesSameAnswers[] = {
+  // Answer 1
+  // ghs.l.google.com in DNS format.
+  0x03, 'g', 'h', 's',
+  0x01, 'l',
+  0x06, 'g', 'o', 'o', 'g', 'l', 'e',
+  0x03, 'c', 'o', 'm',
+  0x00,
+  0x00, 0x01,         // TYPE is A.
+  0x00, 0x01,         // CLASS is IN.
+  0x00, 0x00,         // TTL (4 bytes) is 53 seconds.
+  0x00, 0x35,
+  0x00, 0x04,         // RDLENGTH is 4 bytes.
+  0x4a, 0x7d,         // RDATA is the IP: 74.125.95.121
+  0x5f, 0x79,
+
+  // Answer 2
+  // Pointer to answer 1
+  0xc0, 0x00,
+  0x00, 0x01,         // TYPE is A.
+  0x00, 0x01,         // CLASS is IN.
+  0x00, 0x00,         // TTL (4 bytes) is 112 seconds.
+  0x00, 0x70,
+  0x00, 0x04,         // RDLENGTH is 4 bytes.
+  0x4a, 0x7d,         // RDATA is the IP: 74.125.95.121
+  0x5f, 0x79,
+};
+
+class RecordRemovalMock {
+ public:
+  MOCK_METHOD1(OnRecordRemoved, void(const RecordParsed*));
+};
+
+class MDnsCacheTest : public ::testing::Test {
+ public:
+  MDnsCacheTest()
+      : default_time_(base::Time::FromDoubleT(1234.0)),
+        cache_(base::Bind(&RecordRemovalMock::OnRecordRemoved,
+                          base::Unretained(&record_removal_))) {}
+  virtual ~MDnsCacheTest() {}
+
+ protected:
+  base::Time default_time_;
+  StrictMock<RecordRemovalMock> record_removal_;
+  MDnsCache cache_;
+};
+
+// Test a single insert, corresponding lookup, and unsuccessful lookup.
+TEST_F(MDnsCacheTest, InsertLookupSingle) {
+  DnsRecordParser parser(kT1ResponseDatagram, sizeof(kT1ResponseDatagram),
+                         sizeof(dns_protocol::Header));
+  parser.SkipQuestion();
+
+  scoped_ptr<const RecordParsed> record1;
+  scoped_ptr<const RecordParsed> record2;
+  std::vector<const RecordParsed*> results;
+
+  record1 = RecordParsed::CreateFrom(&parser, default_time_);
+  record2 = RecordParsed::CreateFrom(&parser, default_time_);
+
+  EXPECT_EQ(MDnsCache::RecordAdded, cache_.UpdateDnsRecord(record1.Pass()));
+
+  EXPECT_EQ(MDnsCache::RecordAdded, cache_.UpdateDnsRecord(record2.Pass()));
+
+  cache_.FindDnsRecords(ARecordRdata::kType, "ghs.l.google.com", &results,
+                        default_time_);
+
+  EXPECT_EQ(1u, results.size());
+  EXPECT_EQ(default_time_, results.front()->time_created());
+
+  EXPECT_EQ("ghs.l.google.com", results.front()->name());
+
+  results.clear();
+  cache_.FindDnsRecords(PtrRecordRdata::kType, "ghs.l.google.com", &results,
+                        default_time_);
+
+  EXPECT_EQ(0u, results.size());
+}
+
+// Test that records expire when their ttl has passed.
+TEST_F(MDnsCacheTest, Expiration) {
+  DnsRecordParser parser(kT1ResponseDatagram, sizeof(kT1ResponseDatagram),
+                         sizeof(dns_protocol::Header));
+  parser.SkipQuestion();
+  scoped_ptr<const RecordParsed> record1;
+  scoped_ptr<const RecordParsed> record2;
+
+  std::vector<const RecordParsed*> results;
+  const RecordParsed* record_to_be_deleted;
+
+  record1 = RecordParsed::CreateFrom(&parser, default_time_);
+  base::TimeDelta ttl1 = base::TimeDelta::FromSeconds(record1->ttl());
+
+  record2 = RecordParsed::CreateFrom(&parser, default_time_);
+  base::TimeDelta ttl2 = base::TimeDelta::FromSeconds(record2->ttl());
+  record_to_be_deleted = record2.get();
+
+  EXPECT_EQ(MDnsCache::RecordAdded, cache_.UpdateDnsRecord(record1.Pass()));
+  EXPECT_EQ(MDnsCache::RecordAdded, cache_.UpdateDnsRecord(record2.Pass()));
+
+  cache_.FindDnsRecords(ARecordRdata::kType, "ghs.l.google.com", &results,
+                        default_time_);
+
+  EXPECT_EQ(1u, results.size());
+
+  EXPECT_EQ(default_time_ + ttl2, cache_.next_expiration());
+
+
+  cache_.FindDnsRecords(ARecordRdata::kType, "ghs.l.google.com", &results,
+                        default_time_ + ttl2);
+
+  EXPECT_EQ(0u, results.size());
+
+  EXPECT_CALL(record_removal_, OnRecordRemoved(record_to_be_deleted));
+
+  cache_.CleanupRecords(default_time_ + ttl2);
+
+  // To make sure that we've indeed removed them from the map, check no funny
+  // business happens once they're deleted for good.
+
+  EXPECT_EQ(default_time_ + ttl1, cache_.next_expiration());
+  cache_.FindDnsRecords(ARecordRdata::kType, "ghs.l.google.com", &results,
+                        default_time_ + ttl2);
+
+  EXPECT_EQ(0u, results.size());
+}
+
+// Test that a new record replacing one with the same identity (name/rrtype for
+// unique records) causes the cache to output a "record changed" event.
+TEST_F(MDnsCacheTest, RecordChange) {
+  DnsRecordParser parser(kTestResponsesDifferentAnswers,
+                         sizeof(kTestResponsesDifferentAnswers),
+                         0);
+
+  scoped_ptr<const RecordParsed> record1;
+  scoped_ptr<const RecordParsed> record2;
+  std::vector<const RecordParsed*> results;
+
+  record1 = RecordParsed::CreateFrom(&parser, default_time_);
+  record2 = RecordParsed::CreateFrom(&parser, default_time_);
+
+  EXPECT_EQ(MDnsCache::RecordAdded, cache_.UpdateDnsRecord(record1.Pass()));
+  EXPECT_EQ(MDnsCache::RecordChanged,
+            cache_.UpdateDnsRecord(record2.Pass()));
+}
+
+// Test that a new record replacing an otherwise identical one already in the
+// cache causes the cache to output a "no change" event.
+TEST_F(MDnsCacheTest, RecordNoChange) {
+  DnsRecordParser parser(kTestResponsesSameAnswers,
+                         sizeof(kTestResponsesSameAnswers),
+                         0);
+
+  scoped_ptr<const RecordParsed> record1;
+  scoped_ptr<const RecordParsed> record2;
+  std::vector<const RecordParsed*> results;
+
+  record1 = RecordParsed::CreateFrom(&parser, default_time_);
+  record2 = RecordParsed::CreateFrom(&parser, default_time_ +
+                                     base::TimeDelta::FromSeconds(1));
+
+  EXPECT_EQ(MDnsCache::RecordAdded, cache_.UpdateDnsRecord(record1.Pass()));
+  EXPECT_EQ(MDnsCache::NoChange, cache_.UpdateDnsRecord(record2.Pass()));
+}
+
+// Test that the next expiration time of the cache is updated properly on record
+// insertion.
+TEST_F(MDnsCacheTest, RecordPreemptExpirationTime) {
+  DnsRecordParser parser(kTestResponsesSameAnswers,
+                         sizeof(kTestResponsesSameAnswers),
+                         0);
+
+  scoped_ptr<const RecordParsed> record1;
+  scoped_ptr<const RecordParsed> record2;
+  std::vector<const RecordParsed*> results;
+
+  record1 = RecordParsed::CreateFrom(&parser, default_time_);
+  record2 = RecordParsed::CreateFrom(&parser, default_time_);
+  base::TimeDelta ttl1 = base::TimeDelta::FromSeconds(record1->ttl());
+  base::TimeDelta ttl2 = base::TimeDelta::FromSeconds(record2->ttl());
+
+  EXPECT_EQ(base::Time(), cache_.next_expiration());
+  EXPECT_EQ(MDnsCache::RecordAdded, cache_.UpdateDnsRecord(record2.Pass()));
+  EXPECT_EQ(default_time_ + ttl2, cache_.next_expiration());
+  EXPECT_EQ(MDnsCache::NoChange, cache_.UpdateDnsRecord(record1.Pass()));
+  EXPECT_EQ(default_time_ + ttl1, cache_.next_expiration());
+}
+}