/// <summary>
/// Create an InetAddress with a fully qualified hostname of the given
/// hostname.
/// </summary>
/// <remarks>
/// Create an InetAddress with a fully qualified hostname of the given
/// hostname. InetAddress does not qualify an incomplete hostname that
/// is resolved via the domain search list.
/// <see cref="System.Net.IPAddress.ToString()"/>
/// will fully qualify the
/// hostname, but it always return the A record whereas the given hostname
/// may be a CNAME.
/// </remarks>
/// <param name="host">a hostname or ip address</param>
/// <returns>InetAddress with the fully qualified hostname or ip</returns>
/// <exception cref="UnknownHostException">if host does not exist</exception>
public virtual IPAddress GetByName(string host)
{
IPAddress addr = null;
if (IPAddressUtil.IsIPv4LiteralAddress(host))
{
// use ipv4 address as-is
byte[] ip = IPAddressUtil.TextToNumericFormatV4(host);
addr = IPAddress.GetByAddress(host, ip);
}
else
{
if (IPAddressUtil.IsIPv6LiteralAddress(host))
{
// use ipv6 address as-is
byte[] ip = IPAddressUtil.TextToNumericFormatV6(host);
addr = IPAddress.GetByAddress(host, ip);
}
else
{
if (host.EndsWith("."))
{
// a rooted host ends with a dot, ex. "host."
// rooted hosts never use the search path, so only try an exact lookup
addr = GetByExactName(host);
}
else
{
if (host.Contains("."))
{
// the host contains a dot (domain), ex. "host.domain"
// try an exact host lookup, then fallback to search list
addr = GetByExactName(host);
if (addr == null)
{
addr = GetByNameWithSearch(host);
}
}
else
{
// it's a simple host with no dots, ex. "host"
// try the search list, then fallback to exact host
IPAddress loopback = Extensions.GetAddressByName(null);
if (Runtime.EqualsIgnoreCase(host, loopback.GetHostName()))
{
addr = IPAddress.GetByAddress(host, loopback.GetAddressBytes());
}
else
{
addr = GetByNameWithSearch(host);
if (addr == null)
{
addr = GetByExactName(host);
}
}
}
}
}
}
// unresolvable!
if (addr == null)
{
throw new UnknownHostException(host);
}
return(addr);
}