// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "net/dns/dns_hosts.h"

#include "base/test/metrics/histogram_tester.h"
#include "base/trace_event/memory_usage_estimator.h"
#include "build/build_config.h"
#include "net/base/cronet_buildflags.h"
#include "net/base/ip_address.h"
#include "testing/gtest/include/gtest/gtest.h"

namespace net {

namespace {

struct ExpectedHostsEntry {
  const char* host;
  AddressFamily family;
  const char* ip;
};

void PopulateExpectedHosts(const ExpectedHostsEntry* entries,
                           size_t num_entries,
                           DnsHosts* expected_hosts_out) {
  for (size_t i = 0; i < num_entries; ++i) {
    DnsHostsKey key(entries[i].host, entries[i].family);
    IPAddress& ip_ref = (*expected_hosts_out)[key];
    ASSERT_TRUE(ip_ref.empty());
    ASSERT_TRUE(ip_ref.AssignFromIPLiteral(entries[i].ip));
    ASSERT_EQ(ip_ref.size(),
        (entries[i].family == ADDRESS_FAMILY_IPV4) ? 4u : 16u);
  }
}

TEST(DnsHostsTest, ParseHosts) {
  const std::string kContents =
      "127.0.0.1       localhost # standard\n"
      "\n"
      "1.0.0.1 localhost # ignored, first hit above\n"
      "fe00::x example company # ignored, malformed IPv6\n"
      "1.0.0.300 company # ignored, malformed IPv4\n"
      "1.0.0.1 # ignored, missing hostname\n"
      "1.0.0.1\t CoMpANy # normalized to 'company' \n"
      "::1\tlocalhost ip6-localhost ip6-loopback # comment # within a comment\n"
      "\t fe00::0 ip6-localnet\r\n"
      "2048::2 example\n"
      "2048::1 company example # ignored for 'example' \n"
      "127.0.0.1 cache1\n"
      "127.0.0.1 cache2 # should reuse parsed IP\n"
      "256.0.0.0 cache3 # bogus IP should not clear parsed IP cache\n"
      "127.0.0.1 cache4 # should still be reused\n"
      "127.0.0.2 cache5\n"
      "127.0.0.3 .foo # entries with leading dot are ignored\n"
      "127.0.0.3 . # just a dot is ignored\n"
      "127.0.0.4 bar. # trailing dot is allowed, for now\n"
      "gibberish\n"
      "127.0.0.5 fóó.test # canonicalizes to 'xn--f-vgaa.test' due to RFC3490\n"
      "127.0.0.6 127.0.0.1 # ignore IP host\n"
      "2048::3 [::1] # ignore IP host";

  const ExpectedHostsEntry kEntries[] = {
      {"localhost", ADDRESS_FAMILY_IPV4, "127.0.0.1"},
      {"company", ADDRESS_FAMILY_IPV4, "1.0.0.1"},
      {"localhost", ADDRESS_FAMILY_IPV6, "::1"},
      {"ip6-localhost", ADDRESS_FAMILY_IPV6, "::1"},
      {"ip6-loopback", ADDRESS_FAMILY_IPV6, "::1"},
      {"ip6-localnet", ADDRESS_FAMILY_IPV6, "fe00::0"},
      {"company", ADDRESS_FAMILY_IPV6, "2048::1"},
      {"example", ADDRESS_FAMILY_IPV6, "2048::2"},
      {"cache1", ADDRESS_FAMILY_IPV4, "127.0.0.1"},
      {"cache2", ADDRESS_FAMILY_IPV4, "127.0.0.1"},
      {"cache4", ADDRESS_FAMILY_IPV4, "127.0.0.1"},
      {"cache5", ADDRESS_FAMILY_IPV4, "127.0.0.2"},
      {"bar.", ADDRESS_FAMILY_IPV4, "127.0.0.4"},
      {"xn--f-vgaa.test", ADDRESS_FAMILY_IPV4, "127.0.0.5"},
  };

  DnsHosts expected_hosts, actual_hosts;
  PopulateExpectedHosts(kEntries, std::size(kEntries), &expected_hosts);

  base::HistogramTester histograms;
  ParseHosts(kContents, &actual_hosts);
  ASSERT_EQ(expected_hosts, actual_hosts);
  histograms.ExpectUniqueSample("Net.DNS.DnsHosts.Count", std::size(kEntries),
                                1);
#if !BUILDFLAG(CRONET_BUILD)
  histograms.ExpectUniqueSample(
      "Net.DNS.DnsHosts.EstimateMemoryUsage",
      base::trace_event::EstimateMemoryUsage(actual_hosts), 1);
#endif
}

TEST(DnsHostsTest, ParseHosts_CommaIsToken) {
  const std::string kContents = "127.0.0.1 comma1,comma2";

  const ExpectedHostsEntry kEntries[] = {
    { "comma1,comma2", ADDRESS_FAMILY_IPV4, "127.0.0.1" },
  };

  DnsHosts expected_hosts, actual_hosts;
  PopulateExpectedHosts(kEntries, std::size(kEntries), &expected_hosts);
  ParseHostsWithCommaModeForTesting(
      kContents, &actual_hosts, PARSE_HOSTS_COMMA_IS_TOKEN);
  ASSERT_EQ(0UL, actual_hosts.size());
}

TEST(DnsHostsTest, ParseHosts_CommaIsWhitespace) {
  std::string kContents = "127.0.0.1 comma1,comma2";

  const ExpectedHostsEntry kEntries[] = {
    { "comma1", ADDRESS_FAMILY_IPV4, "127.0.0.1" },
    { "comma2", ADDRESS_FAMILY_IPV4, "127.0.0.1" },
  };

  DnsHosts expected_hosts, actual_hosts;
  PopulateExpectedHosts(kEntries, std::size(kEntries), &expected_hosts);
  ParseHostsWithCommaModeForTesting(
      kContents, &actual_hosts, PARSE_HOSTS_COMMA_IS_WHITESPACE);
  ASSERT_EQ(expected_hosts, actual_hosts);
}

// Test that the right comma mode is used on each platform.
TEST(DnsHostsTest, ParseHosts_CommaModeByPlatform) {
  std::string kContents = "127.0.0.1 comma1,comma2";
  DnsHosts actual_hosts;
  ParseHosts(kContents, &actual_hosts);

#if BUILDFLAG(IS_APPLE)
  const ExpectedHostsEntry kEntries[] = {
    { "comma1", ADDRESS_FAMILY_IPV4, "127.0.0.1" },
    { "comma2", ADDRESS_FAMILY_IPV4, "127.0.0.1" },
  };
  DnsHosts expected_hosts;
  PopulateExpectedHosts(kEntries, std::size(kEntries), &expected_hosts);
  ASSERT_EQ(expected_hosts, actual_hosts);
#else
  ASSERT_EQ(0UL, actual_hosts.size());
#endif
}

TEST(DnsHostsTest, HostsParser_Empty) {
  DnsHosts hosts;
  ParseHosts("", &hosts);
  EXPECT_EQ(0u, hosts.size());
}

TEST(DnsHostsTest, HostsParser_OnlyWhitespace) {
  DnsHosts hosts;
  ParseHosts(" ", &hosts);
  EXPECT_EQ(0u, hosts.size());
}

TEST(DnsHostsTest, HostsParser_EndsWithNothing) {
  DnsHosts hosts;
  ParseHosts("127.0.0.1 localhost", &hosts);
  EXPECT_EQ(1u, hosts.size());
}

TEST(DnsHostsTest, HostsParser_EndsWithWhitespace) {
  DnsHosts hosts;
  ParseHosts("127.0.0.1 localhost ", &hosts);
  EXPECT_EQ(1u, hosts.size());
}

TEST(DnsHostsTest, HostsParser_EndsWithComment) {
  DnsHosts hosts;
  ParseHosts("127.0.0.1 localhost # comment", &hosts);
  EXPECT_EQ(1u, hosts.size());
}

TEST(DnsHostsTest, HostsParser_EndsWithNewline) {
  DnsHosts hosts;
  ParseHosts("127.0.0.1 localhost\n", &hosts);
  EXPECT_EQ(1u, hosts.size());
}

TEST(DnsHostsTest, HostsParser_EndsWithTwoNewlines) {
  DnsHosts hosts;
  ParseHosts("127.0.0.1 localhost\n\n", &hosts);
  EXPECT_EQ(1u, hosts.size());
}

TEST(DnsHostsTest, HostsParser_EndsWithNewlineAndWhitespace) {
  DnsHosts hosts;
  ParseHosts("127.0.0.1 localhost\n ", &hosts);
  EXPECT_EQ(1u, hosts.size());
}

TEST(DnsHostsTest, HostsParser_EndsWithNewlineAndToken) {
  DnsHosts hosts;
  ParseHosts("127.0.0.1 localhost\ntoken", &hosts);
  EXPECT_EQ(1u, hosts.size());
}

}  // namespace

}  // namespace net