[net/dns] Serve requests from HOSTS file if possible.

net/dns/dns_test_util.cc

+// Copyright (c) 2012 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 "net/dns/dns_test_util.h"
+
+#include <string>
+
+#include "base/bind.h"
+#include "base/memory/weak_ptr.h"
+#include "base/message_loop.h"
+#include "base/sys_byteorder.h"
+#include "net/base/big_endian.h"
+#include "net/base/dns_util.h"
+#include "net/base/io_buffer.h"
+#include "net/base/net_errors.h"
+#include "net/dns/dns_client.h"
+#include "net/dns/dns_config_service.h"
+#include "net/dns/dns_protocol.h"
+#include "net/dns/dns_query.h"
+#include "net/dns/dns_response.h"
+#include "net/dns/dns_transaction.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace net {
+namespace {
+
+// A DnsTransaction which responds with loopback to all queries starting with
+// "ok", fails synchronously on all queries starting with "er", and NXDOMAIN to
+// all others.
+class MockTransaction : public DnsTransaction,
+                        public base::SupportsWeakPtr<MockTransaction> {
+ public:
+  MockTransaction(const std::string& hostname,
+                  uint16 qtype,
+                  const DnsTransactionFactory::CallbackType& callback)
+      : hostname_(hostname),
+        qtype_(qtype),
+        callback_(callback),
+        started_(false) {
+  }
+
+  virtual const std::string& GetHostname() const OVERRIDE {
+    return hostname_;
+  }
+
+  virtual uint16 GetType() const OVERRIDE {
+    return qtype_;
+  }
+
+  virtual int Start() OVERRIDE {
+    EXPECT_FALSE(started_);
+    started_ = true;
+    if (hostname_.substr(0, 2) == "er")
+      return ERR_NAME_NOT_RESOLVED;
+    // Using WeakPtr to cleanly cancel when transaction is destroyed.
+    MessageLoop::current()->PostTask(
+        FROM_HERE,
+        base::Bind(&MockTransaction::Finish, AsWeakPtr()));
+    return ERR_IO_PENDING;
+  }
+
+ private:
+  void Finish() {
+    if (hostname_.substr(0, 2) == "ok") {
+      std::string qname;
+      DNSDomainFromDot(hostname_, &qname);
+      DnsQuery query(0, qname, qtype_);
+
+      DnsResponse response;
+      char* buffer = response.io_buffer()->data();
+      int nbytes = query.io_buffer()->size();
+      memcpy(buffer, query.io_buffer()->data(), nbytes);
+
+      const uint16 kPointerToQueryName =
+          static_cast<uint16>(0xc000 | sizeof(net::dns_protocol::Header));
+
+      const uint32 kTTL = 86400;  // One day.
+
+      // Size of RDATA which is a IPv4 or IPv6 address.
+      size_t rdata_size = qtype_ == net::dns_protocol::kTypeA ?
+                          net::kIPv4AddressSize : net::kIPv6AddressSize;
+
+      // 12 is the sum of sizes of the compressed name reference, TYPE,
+      // CLASS, TTL and RDLENGTH.
+      size_t answer_size = 12 + rdata_size;
+
+      // Write answer with loopback IP address.
+      reinterpret_cast<dns_protocol::Header*>(buffer)->ancount = htons(1);
+      BigEndianWriter writer(buffer + nbytes, answer_size);
+      writer.WriteU16(kPointerToQueryName);
+      writer.WriteU16(qtype_);
+      writer.WriteU16(net::dns_protocol::kClassIN);
+      writer.WriteU32(kTTL);
+      writer.WriteU16(rdata_size);
+      if (qtype_ == net::dns_protocol::kTypeA) {
+        char kIPv4Loopback[] = { 0x7f, 0, 0, 1 };
+        writer.WriteBytes(kIPv4Loopback, sizeof(kIPv4Loopback));
+      } else {
+        char kIPv6Loopback[] = { 0, 0, 0, 0, 0, 0, 0, 0,
+                                 0, 0, 0, 0, 0, 0, 0, 1 };
+        writer.WriteBytes(kIPv6Loopback, sizeof(kIPv6Loopback));
+      }
+
+      EXPECT_TRUE(response.InitParse(nbytes + answer_size, query));
+      callback_.Run(this, OK, &response);
+    } else {
+      callback_.Run(this, ERR_NAME_NOT_RESOLVED, NULL);
+    }
+  }
+
+  const std::string hostname_;
+  const uint16 qtype_;
+  DnsTransactionFactory::CallbackType callback_;
+  bool started_;
+};
+
+
+// A DnsTransactionFactory which creates MockTransaction.
+class MockTransactionFactory : public DnsTransactionFactory {
+ public:
+  MockTransactionFactory() {}
+  virtual ~MockTransactionFactory() {}
+
+  virtual scoped_ptr<DnsTransaction> CreateTransaction(
+      const std::string& hostname,
+      uint16 qtype,
+      const DnsTransactionFactory::CallbackType& callback,
+      const BoundNetLog&) OVERRIDE {
+    return scoped_ptr<DnsTransaction>(
+        new MockTransaction(hostname, qtype, callback));
+  }
+};
+
+// MockDnsClient provides MockTransactionFactory.
+class MockDnsClient : public DnsClient {
+ public:
+  explicit MockDnsClient(const DnsConfig& config) : config_(config) {}
+  virtual ~MockDnsClient() {}
+
+  virtual void SetConfig(const DnsConfig& config) OVERRIDE {
+    config_ = config;
+  }
+
+  virtual const DnsConfig* GetConfig() const OVERRIDE {
+    return config_.IsValid() ? &config_ : NULL;
+  }
+
+  virtual DnsTransactionFactory* GetTransactionFactory() OVERRIDE {
+    return config_.IsValid() ? &factory_ : NULL;
+  }
+
+ private:
+  DnsConfig config_;
+  MockTransactionFactory factory_;
+};
+
+}  // namespace
+
+// static
+scoped_ptr<DnsClient> CreateMockDnsClient(const DnsConfig& config) {
+  return scoped_ptr<DnsClient>(new MockDnsClient(config));
+}
+
+}  // namespace net
+