using System;using System.Net;using System.Net.Sockets;using System.Collections.Concurrent;using System.Threading;using System.Threading.Tasks;using System.Collections.Generic;
public class PScan3{
 public static string SweepSrc(string prefix,int from,int to,int[] ports,int conc,int timeoutMs,string srcIp){
  var hits=new ConcurrentDictionary<string,ConcurrentBag<int>>();
  var sem=new SemaphoreSlim(conc); var tasks=new List<Task>();
  IPAddress src=null; try{ src=IPAddress.Parse(srcIp); }catch{}
  for(int i=from;i<=to;i++){
   string host=prefix+i; hits[host]=new ConcurrentBag<int>();
   foreach(int p in ports){
    int port=p; string h=host; sem.Wait();
    tasks.Add(Task.Run(async ()=>{
     try{
      using(var c=new TcpClient()){
       if(src!=null){ try{ c.Client.Bind(new IPEndPoint(src,0)); }catch{} }
       var t=c.ConnectAsync(h,port); var done=await Task.WhenAny(t,Task.Delay(timeoutMs)); if(done==t&&c.Connected){ hits[h].Add(port); }
      }
     }catch{}
     finally{ sem.Release(); }
    }));
   }
  }
  Task.WaitAll(tasks.ToArray());
  var sb=new System.Text.StringBuilder();
  foreach(var kv in hits){ if(kv.Value.Count>0){ var l=new List<int>(kv.Value); l.Sort(); sb.Append(kv.Key).Append('=').Append(string.Join(",",l)).Append(';'); } }
  return sb.ToString();
 }
}