public static NetworkInterface GetBestInterface(v4addr addr)
{
var ifs = (from adapter in NetworkInterface.GetAllNetworkInterfaces()
where adapter.OperationalStatus == OperationalStatus.Up && adapter.Supports(NetworkInterfaceComponent.IPv4)
select adapter).ToList();
NetworkInterface candidate = null;
if (ifs.Count == 1)
{
candidate = ifs.First();
}
else if (ifs.Count > 1)
{
// more than one running network interface
string tr = CallTracert($" -d -h 1 {addr}");
var matches = Regex.Matches(tr, @"(\d{1,3}\.){3}\d{1,3}");
if (matches.Count == 2)
{
var targetGateway = new v4addr(matches[1].Value);
Logger.Debug($"Searching for gateway {targetGateway}");
uint targetInterfaceIndex = (from row in IPNetHelper.GetCurrentForwardTable()
where row.dwForwardNextHop == targetGateway.ToUInt32()
select row.dwForwardIfIndex).FirstOrDefault();
candidate =
ifs.FirstOrDefault(a => a.GetIPProperties().GetIPv4Properties().Index == targetInterfaceIndex);
if (candidate != null)
{
Logger.Debug($"find interface({targetInterfaceIndex}) {candidate.Name}");
}
}
else
{
Logger.Error("Trace route error.");
Logger.Debug(tr);
}
}
return(candidate);
}
protected bool Equals(v4addr other)
{
return(Equals(Addr, other.Addr));
}
