// 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 <resolv.h>

#include "base/sys_byteorder.h"
#include "net/dns/dns_config_service_posix.h"

#include "testing/gtest/include/gtest/gtest.h"

namespace net {
namespace {

// MAXNS is normally 3, but let's test 4 if possible.
const char* kNameserversIPv4[] = {
    "8.8.8.8",
    "192.168.1.1",
    "63.1.2.4",
    "1.0.0.1",
};

#if defined(OS_LINUX)
const char* kNameserversIPv6[] = {
    NULL,
    "2001:DB8:0::42",
    NULL,
    "::FFFF:129.144.52.38",
};
#endif

// Fills in |res| with sane configuration.
void InitializeResState(res_state res) {
  memset(res, 0, sizeof(*res));
  res->options = RES_INIT | RES_RECURSE | RES_DEFNAMES | RES_DNSRCH |
                 RES_ROTATE;
  res->ndots = 2;
  res->retrans = 4;
  res->retry = 7;

  const char kDnsrch[] = "chromium.org" "\0" "example.com";
  memcpy(res->defdname, kDnsrch, sizeof(kDnsrch));
  res->dnsrch[0] = res->defdname;
  res->dnsrch[1] = res->defdname + sizeof("chromium.org");

  for (unsigned i = 0; i < arraysize(kNameserversIPv4) && i < MAXNS; ++i) {
    struct sockaddr_in sa;
    sa.sin_family = AF_INET;
    sa.sin_port = base::HostToNet16(NS_DEFAULTPORT + i);
    inet_pton(AF_INET, kNameserversIPv4[i], &sa.sin_addr);
    res->nsaddr_list[i] = sa;
    ++res->nscount;
  }

#if defined(OS_LINUX)
  // Install IPv6 addresses, replacing the corresponding IPv4 addresses.
  unsigned nscount6 = 0;
  for (unsigned i = 0; i < arraysize(kNameserversIPv6) && i < MAXNS; ++i) {
    if (!kNameserversIPv6[i])
      continue;
    // Must use malloc to mimick res_ninit.
    struct sockaddr_in6 *sa6;
    sa6 = (struct sockaddr_in6 *)malloc(sizeof(*sa6));
    sa6->sin6_family = AF_INET6;
    sa6->sin6_port = base::HostToNet16(NS_DEFAULTPORT - i);
    inet_pton(AF_INET6, kNameserversIPv6[i], &sa6->sin6_addr);
    res->_u._ext.nsaddrs[i] = sa6;
    memset(&res->nsaddr_list[i], 0, sizeof res->nsaddr_list[i]);
    ++nscount6;
  }
  res->_u._ext.nscount6 = nscount6;
#endif
}

void CloseResState(res_state res) {
#if defined(OS_LINUX)
  for (int i = 0; i < res->nscount; ++i) {
    if (res->_u._ext.nsaddrs[i] != NULL)
      free(res->_u._ext.nsaddrs[i]);
  }
#endif
}

void InitializeExpectedConfig(DnsConfig* config) {
  config->ndots = 2;
  config->timeout = base::TimeDelta::FromSeconds(4);
  config->attempts = 7;
  config->rotate = true;
  config->edns0 = false;
  config->append_to_multi_label_name = true;
  config->search.clear();
  config->search.push_back("chromium.org");
  config->search.push_back("example.com");

  config->nameservers.clear();
  for (unsigned i = 0; i < arraysize(kNameserversIPv4) && i < MAXNS; ++i) {
    IPAddressNumber ip;
    ParseIPLiteralToNumber(kNameserversIPv4[i], &ip);
    config->nameservers.push_back(IPEndPoint(ip, NS_DEFAULTPORT + i));
  }

#if defined(OS_LINUX)
  for (unsigned i = 0; i < arraysize(kNameserversIPv6) && i < MAXNS; ++i) {
    if (!kNameserversIPv6[i])
      continue;
    IPAddressNumber ip;
    ParseIPLiteralToNumber(kNameserversIPv6[i], &ip);
    config->nameservers[i] = IPEndPoint(ip, NS_DEFAULTPORT - i);
  }
#endif
}

TEST(DnsConfigServicePosixTest, ConvertResStateToDnsConfig) {
  struct __res_state res;
  DnsConfig config;
  EXPECT_FALSE(config.IsValid());
  InitializeResState(&res);
  ASSERT_EQ(internal::CONFIG_PARSE_POSIX_OK,
            internal::ConvertResStateToDnsConfig(res, &config));
  CloseResState(&res);
  EXPECT_TRUE(config.IsValid());

  DnsConfig expected_config;
  EXPECT_FALSE(expected_config.EqualsIgnoreHosts(config));
  InitializeExpectedConfig(&expected_config);
  EXPECT_TRUE(expected_config.EqualsIgnoreHosts(config));
}

TEST(DnsConfigServicePosixTest, RejectEmptyNameserver) {
  struct __res_state res = {};
  res.options = RES_INIT | RES_RECURSE | RES_DEFNAMES | RES_DNSRCH;
  const char kDnsrch[] = "chromium.org";
  memcpy(res.defdname, kDnsrch, sizeof(kDnsrch));
  res.dnsrch[0] = res.defdname;

  struct sockaddr_in sa = {};
  sa.sin_family = AF_INET;
  sa.sin_port = base::HostToNet16(NS_DEFAULTPORT);
  sa.sin_addr.s_addr = INADDR_ANY;
  res.nsaddr_list[0] = sa;
  sa.sin_addr.s_addr = 0xCAFE1337;
  res.nsaddr_list[1] = sa;
  res.nscount = 2;

  DnsConfig config;
  EXPECT_EQ(internal::CONFIG_PARSE_POSIX_NULL_ADDRESS,
            internal::ConvertResStateToDnsConfig(res, &config));

  sa.sin_addr.s_addr = 0xDEADBEEF;
  res.nsaddr_list[0] = sa;
  EXPECT_EQ(internal::CONFIG_PARSE_POSIX_OK,
            internal::ConvertResStateToDnsConfig(res, &config));
}

}  // namespace
}  // namespace net