Added DnsQuery class

net/base/dns_response_unittest.cc

+// Copyright (c) 2011 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/base/address_list.h"
+#include "net/base/dns_response.h"
+#include "net/base/net_errors.h"
+#include "net/base/sys_addrinfo.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace net {
+
+// DNS response consists of a header followed by a question followed by
+// answer.  Header format, question format and response format are
+// described below.  For the meaning of specific fields, please see RFC
+// 1035.
+
+// Header format.
+//                                  1  1  1  1  1  1
+//    0  1  2  3  4  5  6  7  8  9  0  1  2  3  4  5
+//  +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+//  |                      ID                       |
+//  +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+//  |QR|   Opcode  |AA|TC|RD|RA|   Z    |   RCODE   |
+//  +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+//  |                    QDCOUNT                    |
+//  +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+//  |                    ANCOUNT                    |
+//  +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+//  |                    NSCOUNT                    |
+//  +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+//  |                    ARCOUNT                    |
+//  +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+
+// Question format.
+//                                  1  1  1  1  1  1
+//    0  1  2  3  4  5  6  7  8  9  0  1  2  3  4  5
+//  +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+//  |                                               |
+//  /                     QNAME                     /
+//  /                                               /
+//  +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+//  |                     QTYPE                     |
+//  +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+//  |                     QCLASS                    |
+//  +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+
+// Answser format.
+//                                  1  1  1  1  1  1
+//    0  1  2  3  4  5  6  7  8  9  0  1  2  3  4  5
+//  +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+//  |                                               |
+//  /                                               /
+//  /                      NAME                     /
+//  |                                               |
+//  +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+//  |                      TYPE                     |
+//  +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+//  |                     CLASS                     |
+//  +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+//  |                      TTL                      |
+//  |                                               |
+//  +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+//  |                   RDLENGTH                    |
+//  +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
+//  /                     RDATA                     /
+//  /                                               /
+//  +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+
+TEST(DnsResponseTest, ResponseWithCnameA) {

[cbentzel, 2011/06/02 21:27:13]

Thanks for including CNAME and making sure that the skip-over-it-logic works.

[cbentzel, 2011/06/02 21:27:13]

You should add a lot more tests for the invalid cases, like non-3 rdata or
non-echoed-back question, or invalid id, etc.

If necessary you can just do a TODO, but it's pretty easy to set up a unit test
for parsing. 

[agayev, 2011/06/02 22:33:26]

I will add more tests, but I need to stabilize the API first.  Otherwise I will
keep modifying the tests.

+  const std::string kHostname = "codereview.chromium.org";
+  const int kPort = 80;
+
+  DnsQuery q1(kHostname, ADDRESS_FAMILY_IPV4, kPort);
+  uint8 id_hi = q1.id() >> 8, id_lo = q1.id() & 0xff;
+
+  uint8 ip[] = {              // codereview.chromium.org resolves to
+    0x4a, 0x7d, 0x5f, 0x79    // 74.125.95.121
+  };
+
+  uint8 response_data[] = {
+    // Header
+    id_hi, id_lo,             // ID
+    0x81, 0x80,               // Standard query response, no error
+    0x00, 0x01,               // 1 question
+    0x00, 0x02,               // 2 RRs (answers)
+    0x00, 0x00,               // 0 authority RRs
+    0x00, 0x00,               // 0 additional RRs
+
+    // Question
+    0x0a, 0x63, 0x6f, 0x64,   // This part should be echoed back.
+    0x65, 0x72, 0x65, 0x76,
+    0x69, 0x65, 0x77, 0x08,
+    0x63, 0x68, 0x72, 0x6f,
+    0x6d, 0x69, 0x75, 0x6d,
+    0x03, 0x6f, 0x72, 0x67,
+    0x00,
+    0x00, 0x01,
+    0x00, 0x01,
+
+    // Answer 1
+    0xc0, 0x0c,        // NAME is a pointer to name in Question section
+    0x00, 0x05,        // TYPE is CNAME
+    0x00, 0x01,        // CLASS is IN
+    0x00, 0x01,        // TTL is 20 hours, 47 minutes, 48 seconds (4 bytes)
+    0x24, 0x74,
+    0x00, 0x12,        // RDLENGTH is 18 bytes
+    0x03, 0x67, 0x68, 0x73,   // ghs.l.google.com in DNS format.
+    0x01, 0x6c, 0x06, 0x67,
+    0x6f, 0x6f, 0x67, 0x6c,
+    0x65, 0x03, 0x63, 0x6f,
+    0x6d, 0x00,
+
+    // Answer 2
+    0xc0, 0x35,         // NAME is a pointer to name in Question section
+    0x00, 0x01,         // TYPE is A
+    0x00, 0x01,         // CLASS is IN
+    0x00, 0x00,         // TTL is 53 seconds (4 bytes)
+    0x00, 0x35,
+    0x00, 0x04,         // RDLENGTH is 4 bytes
+    ip[0], ip[1], ip[2], ip[3], // RDATA is the IP.
+  };
+
+  // Create a response object and simulate reading into it.
+  DnsResponse r1(&q1);
+  memcpy(r1.io_buffer()->data(), &response_data[0],
+         r1.io_buffer()->size());
+
+  int response_size = arraysize(response_data);
+  AddressList address_list;
+  EXPECT_EQ(0, r1.Parse(response_size, &address_list));
+
+  // Verify AddressList content.
+  size_t sockaddr_size = sizeof(struct sockaddr_in);
+  const struct addrinfo* ai = address_list.head();
+  EXPECT_EQ(kPort, address_list.GetPort());
+
+  // Verify addrinfo part.
+  EXPECT_TRUE(ai != NULL);
+  EXPECT_EQ(AF_INET, ai->ai_family);
+  EXPECT_EQ(SOCK_STREAM, ai->ai_socktype);
+  EXPECT_EQ(sockaddr_size, ai->ai_addrlen);
+
+  // Verify sockaddr_in part.
+  struct sockaddr_in* sa = reinterpret_cast<sockaddr_in*>(ai->ai_addr);
+  ASSERT_TRUE(sa != NULL);
+  EXPECT_EQ(AF_INET, sa->sin_family);
+  EXPECT_EQ(kPort, ntohs(sa->sin_port));
+  EXPECT_EQ(0, memcmp(&sa->sin_addr, &ip[0], kIPv4AddressSize));
+}
+
+}  // namespace net