public void TestGenerateId()
{
var randomIds = Enumerable.Range(0, ushort.MaxValue).Select(x => DnsQueryFactory.GenerateId());
// Check the distribution is between 10% and 100% of the available values
Assert.InRange(randomIds.Distinct().Count(), ushort.MaxValue / 10, ushort.MaxValue);
}
public async Task TestQuery()
{
using var tokenSource = new CancellationTokenSource(TimeSpan.FromMilliseconds(500));
var endpoint = GenerateEndPoint();
// Create a real upstream DNS client to serve the request (todo: mock this)
using var upstream = new DnsUdpClient(IPAddress.Parse("1.1.1.1"));
// Create a loopback server
using var server = new DnsUdpServer(endpoint, upstream);
// Start recieving
using var receiveTask = server.Listen(tokenSource.Token);
// Create a loopback DNS client to talk to the server
using var client = new DnsUdpClient(endpoint);
try
{
var query = DnsQueryFactory.CreateQuery("google.com");
// Send a DNS request to the server, verify the results
var response = await client.Query(query, tokenSource.Token);
Assert.Equal(query.Id, response.Header.Id);
Assert.Equal(query.Host, response.Header.Host);
Assert.True(response.Answers.Count > 0);
}
finally
{
tokenSource.Cancel();
await receiveTask;
}
}
public void TestOrAllowedByDefault()
{
var dnsFilter = new DnsDomainSuffixFilter("example.com");
Assert.False(dnsFilter.IsPermitted(DnsQueryFactory.CreateQuery("test.example.com")));
Assert.True(dnsFilter.IsPermitted(DnsQueryFactory.CreateQuery("test.example.org")));
Assert.False(dnsFilter.IsPermitted(DnsQueryFactory.CreateQuery("test.example.org.example.com")));
Assert.True(dnsFilter.IsPermitted(DnsQueryFactory.CreateQuery("test.example.com.example.org")));
}
public void TestCreateReverseQueryIPv6()
{
var header = DnsQueryFactory.CreateReverseQuery(IPAddress.Parse("2600:9000:2015:3600:1a:36dc:e5c0:93a1"));
Assert.Equal("1.a.3.9.0.c.5.e.c.d.6.3.a.1.0.0.6.3.5.1.0.2.0.0.0.9.0.0.6.2.ip6.arpa", header.Host);
Assert.True(header.Id > 0);
Assert.Equal(DnsQueryClass.IN, header.QueryClass);
Assert.Equal(DnsQueryType.PTR, header.QueryType);
Assert.Equal(DnsOperationCode.QUERY, header.OperationCode);
Assert.Equal(1, header.QuestionCount);
Assert.True(header.RecusionDesired);
}
public void TestCreateReverseQueryIPv4()
{
var header = DnsQueryFactory.CreateReverseQuery(IPAddress.Parse("1.2.3.4"));
Assert.Equal("4.3.2.1.in-addr.arpa", header.Host);
Assert.True(header.Id > 0);
Assert.Equal(DnsQueryClass.IN, header.QueryClass);
Assert.Equal(DnsQueryType.PTR, header.QueryType);
Assert.Equal(DnsOperationCode.QUERY, header.OperationCode);
Assert.Equal(1, header.QuestionCount);
Assert.True(header.RecusionDesired);
}
public void TestCreateQuery()
{
var header = DnsQueryFactory.CreateQuery("example.com", DnsQueryType.CNAME);
Assert.Equal("example.com", header.Host);
Assert.True(header.Id > 0);
Assert.Equal(DnsQueryClass.IN, header.QueryClass);
Assert.Equal(DnsQueryType.CNAME, header.QueryType);
Assert.Equal(DnsOperationCode.QUERY, header.OperationCode);
Assert.Equal(1, header.QuestionCount);
Assert.True(header.RecusionDesired);
}
public static async Task RunQuery(this IDnsClient client, string host, DnsQueryType queryType, DnsResponseCode expectedResponseCode = DnsResponseCode.NoError)
{
var query = DnsQueryFactory.CreateQuery(host, queryType);
var answer = await client.Query(query);
Assert.Equal(host, answer.Header.Host);
Assert.Equal(query.Id, answer.Header.Id);
Assert.Equal(expectedResponseCode, answer.Header.ResponseCode);
if (expectedResponseCode == DnsResponseCode.NoError && !answer.Header.Truncation)
{
Assert.True(answer.Answers.Count > 0);
}
else
{
Assert.Empty(answer.Answers);
}
}
public async Task TestLookupTimeout()
{
// Reserved - see https://en.wikipedia.org/wiki/Reserved_IP_addresses
using var client = new DnsUdpClient(new NullLogger <DnsUdpClient>(), IPAddress.Parse("192.88.99.0"));
await Assert.ThrowsAsync <DnsClientTimeoutException>(() => client.Query(DnsQueryFactory.CreateQuery("alanedwardes.com"), CancellationToken.None));
}