Package com.frostwire.jlibtorrent

Class UdpEndpoint

java.lang.Object
com.frostwire.jlibtorrent.UdpEndpoint
All Implemented Interfaces:
Cloneable
public final class UdpEndpoint extends Object implements Cloneable
A network address and UDP port pair for DHT and uTP protocol communication.

UdpEndpoint represents a remote node's address and UDP port in the DHT network or for uTP (Micro Transport Protocol) connections. Unlike TcpEndpoint which is used for traditional BitTorrent peer connections on TCP, UdpEndpoint identifies nodes participating in the Distributed Hash Table (DHT) or peers using the uTP protocol over UDP.

Understanding UDP Endpoints:
UDP endpoints represent peer/node locations for UDP-based protocols:

  • DHT Communication: DHT operations use UDP to query remote nodes
  • DHT Node Discovery: DHT bootstrap and lookups return lists of UdpEndpoints
  • uTP Connections: Alternative to TCP using UDP with Micro Transport Protocol
  • Address Format: Supports both IPv4 (192.168.1.1:6881) and IPv6 addresses

Creating UDP Endpoints: 

 // From IPv4 address and port
 UdpEndpoint dhtNode1 = new UdpEndpoint("203.0.113.50", 6881);
 System.out.println(dhtNode1);  // Output: udp://203.0.113.50:6881

 // From IPv6 address
 UdpEndpoint dhtNode2 = new UdpEndpoint("2001:db8::8a2e:370:7334", 6881);
 System.out.println(dhtNode2);  // Output: udp://2001:db8::8a2e:370:7334:6881

 // From Address object
 Address dhtNodeAddr = new Address("151.101.1.140");
 UdpEndpoint bootstrapNode = new UdpEndpoint(dhtNodeAddr, 6881);

 // Create empty endpoint (useful for initialization)
 UdpEndpoint empty = new UdpEndpoint();

Querying Endpoint Information: 

 UdpEndpoint node = new UdpEndpoint("162.125.18.133", 6881);

 // Get the address component
 Address addr = node.address();
 boolean isV4 = addr.isV4();  // true for IPv4
 boolean isV6 = addr.isV6();  // true for IPv6
 String ipString = addr.toString();

 // Get the port
 int port = node.port();  // 6881

 // Get full string representation with udp:// prefix
 String fullAddr = node.toString();  // "udp://162.125.18.133:6881"

DHT Bootstrap Nodes:

Bootstrap nodes are well-known DHT nodes used to join the DHT network: 

 SessionManager sm = new SessionManager();
 sm.start();

 // Common DHT bootstrap nodes (well-known, public DHT nodes)
 UdpEndpoint[] bootstrapNodes = {
     new UdpEndpoint("router.bittorrent.com", 6881),
     new UdpEndpoint("dht.transmissionbt.com", 6881),
     new UdpEndpoint("router.utorrent.com", 6881),
     new UdpEndpoint("208.67.72.220", 6881)  // OpenDNS
 };

 // Bootstrap DHT by adding these nodes to routing table
 for (UdpEndpoint node : bootstrapNodes) {
     try {
         sm.dhtBootstrap(node);
     } catch (Exception e) {
         System.out.println("Could not connect to " + node);
     }
 }

DHT Lookup Operations: 

 // Perform DHT lookup (uses UDP endpoints internally)
 Sha1Hash infoHash = new Sha1Hash("d8e8fca2dc0f896fd7cb4cb0031ba249");
 java.util.ArrayList<TcpEndpoint> peers = sm.dhtGetPeers(infoHash, 20);

 // The DHT communicates with UDP endpoints to find these TCP peers

DHT Routing Table Statistics: 

 // Monitor DHT bucket population (uses UdpEndpoints internally)
 sm.addListener(new AlertListener() {
     public int[] types() {
         return new int[] {AlertType.DHT_STATS.swig()};
     }

     public void alert(Alert<?> alert) {
         DhtStatsAlert a = (DhtStatsAlert) alert;
         List<DhtRoutingBucket> buckets = a.routingBuckets();

         int totalNodes = 0;
         for (DhtRoutingBucket bucket : buckets) {
             totalNodes += bucket.numNodes();
             // Each node tracked is conceptually a UdpEndpoint
         }

         System.out.println("DHT routing table has \" + totalNodes + \" nodes\");
     }
 });

Comparison: TCP Endpoint vs UDP Endpoint: 

 ┌─────────────────────────────┬─────────────────┬──────────────────┐
 │ Characteristic              │ TcpEndpoint     │ UdpEndpoint      │
 ├─────────────────────────────┼─────────────────┼──────────────────┤
 │ Protocol                    │ TCP             │ UDP              │
 │ Purpose                     │ Peer data xfer  │ DHT/uTP          │
 │ Connection State            │ Connected       │ Connectionless   │
 │ String Format               │ 192.168.1.1:80  │ udp://192....:80 │
 │ IPv6 Format                 │ [::1]:80        │ [::1]:80         │
 │ Typical BitTorrent Usage    │ Blocks exchange │ Node discovery   │
 │ Number per Peer             │ 1 per torrent   │ Many (DHT)       │
 └─────────────────────────────┴─────────────────┴──────────────────┘

Performance Notes:

  • UDP endpoints are lightweight and frequently created/destroyed
  • DHT operations may create thousands of UdpEndpoint references internally
  • String constructor performs IP address validation; invalid IPs throw immediately
  • Cloning is supported for creating copies of endpoint references
See Also:

  • Constructor Details

    • UdpEndpoint

      public UdpEndpoint(com.frostwire.jlibtorrent.swig.udp_endpoint endp)

    • UdpEndpoint

      public UdpEndpoint()

    • UdpEndpoint

      public UdpEndpoint(Address address, int port)

    • UdpEndpoint

      public UdpEndpoint(String ip, int port)

  • Method Details

    • swig

      public com.frostwire.jlibtorrent.swig.udp_endpoint swig()

    • address

      public Address address()

    • port

      public int port()
      Get the port associated with the endpoint. The port number is always in the host's byte order.
      Returns:
      the port

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • clone

      public UdpEndpoint clone()
      Overrides:
      clone in class Object