/// <summary>
/// Gets DNS host information for an IP address.
/// </summary>
public StatusCode GetHostByAddress(IPv4 address,
out IPv4HostEntry hostEntry)
{
hostEntry = null;
IPv4 dnsServer = DnsServer;
if (dnsServer == IPv4.Zero)
{
return(StatusCode.NoNameServer);
}
// Formulate request a.b.c.d -> d.b.c.a
IPv4 reversed = new IPv4(ByteOrder.Swap((uint)address));
string name = String.Format("{0}.IN-ADDR.ARPA", reversed);
DebugPrint("Looking up {0}\n", name);
Dns.Query q = new Dns.Query(name, Dns.Type.PTR, Dns.Class.Internet);
Dns.Format answer;
StatusCode askResponse = Ask(dnsServer, q, out answer);
if (askResponse != StatusCode.Success)
{
return(askResponse);
}
VTable.Assert(answer != null);
if (answer.GetRCode() != Dns.RCode.NoError)
{
DebugPrint("Dns query failed: RCode = {0}\n", answer.GetRCode());
return(StatusCode.RequestFailed);
}
hostEntry = new IPv4HostEntry(new string[] {}, new IPv4 [] { address });
ArrayList aliases = new ArrayList();
foreach (Dns.ResourceRecord rr in answer.AnswerRRs)
{
DebugPrint("Answer: Type = {0} Class = {1} TTL = {2}\n",
rr.Type, rr.Class, rr.TtlSeconds);
if ((rr.Type != Dns.Type.PTR && rr.Type != Dns.Type.CNAME) ||
rr.Class != Dns.Class.Internet)
{
continue;
}
byte [] rdata = rr.RData;
if (rdata == null)
{
continue;
}
int offset = 0;
while (offset != rdata.Length)
{
string alias;
offset += Dns.LabelEncoding.GetString(rdata, offset,
out alias);
aliases.Add(alias);
}
}
string[] arr = new string[aliases.Count];
for (int i = 0; i < arr.Length; i++)
{
arr[i] = (string)(aliases[i]);
}
hostEntry.Aliases = arr;
return(StatusCode.Success);
}
public StatusCode Ask(IPv4 dnsServer,
Dns.Query query,
out Dns.Format answer)
{
return(Ask(dnsServer, new Dns.Query [] { query }, out answer));
}
/// <summary>
/// Gets the DNS information for the specified DNS host name.
/// </summary>
public StatusCode GetHostByName(string name,
out IPv4HostEntry hostEntry)
{
hostEntry = null;
IPv4 dnsServer = DnsServer;
if (dnsServer == IPv4.Zero)
{
return(StatusCode.NoNameServer);
}
Dns.Query q = new Dns.Query(name, Dns.Type.A, Dns.Class.Internet);
Dns.Format answer;
StatusCode askResponse = Ask(dnsServer, q, out answer);
if (askResponse != StatusCode.Success)
{
return(askResponse);
}
VTable.Assert(answer != null);
if (answer.GetRCode() != Dns.RCode.NoError)
{
DebugPrint("Dns query failed: RCode = {0}\n", answer.GetRCode());
return(StatusCode.RequestFailed);
}
hostEntry = new IPv4HostEntry(new string [] { name }, new IPv4[] {});
ArrayList addressList = new ArrayList();
foreach (Dns.ResourceRecord rr in answer.AnswerRRs)
{
if (rr.Type != Dns.Type.A || rr.Class != Dns.Class.Internet)
{
continue;
}
byte [] rdata = rr.RData;
if (rdata == null)
{
continue;
}
if ((rdata.Length % IPv4.Length) != 0)
{
continue;
}
int offset = 0;
while (offset != rdata.Length)
{
addressList.Add(IPv4.ParseBytes(rdata, offset));
offset += 4;
}
}
IPv4[] al = hostEntry.AddressList = new IPv4 [addressList.Count];
for (int i = 0; i < addressList.Count; i++)
{
al[i] = (IPv4)addressList[i];
}
return(StatusCode.Success);
}
