Merge pull request #592 from alanmcgovern/compact-peer-ipv4-ipv6

[core] Support ipv4 and ipv6 compact addresses
alanmcgovern · Jan 5, 2023 · 8a40c20 · 8a40c20
2 parents fb05f30 + 4fe7fe3
commit 8a40c20
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Showing 16 changed files with 165 additions and 111 deletions.
diff --git a/src/MonoTorrent.Client/MonoTorrent.Client.Modes/Mode.cs b/src/MonoTorrent.Client/MonoTorrent.Client.Modes/Mode.cs
@@ -249,7 +249,7 @@ protected virtual async void HandlePeerExchangeMessage (PeerId id, PeerExchangeM
                 if ((Manager.Peers.Available + Manager.OpenConnections) >= Manager.Settings.MaximumConnections)
                     return;
 
-                var newPeers = PeerDecoder.Decode (BEncodedString.FromMemory (message.Added));
+                var newPeers = PeerInfo.FromCompact (message.Added.Span, id.Connection.AddressBytes.Length == 16 ? System.Net.Sockets.AddressFamily.InterNetworkV6 : System.Net.Sockets.AddressFamily.InterNetwork);
                 for (int i = 0; i < newPeers.Count && i < message.AddedDotF.Length; i++)
                     newPeers[i] = new PeerInfo (newPeers[i].ConnectionUri, newPeers[i].PeerId, (message.AddedDotF.Span[i] & 0x2) == 0x2);
 

diff --git a/src/MonoTorrent.Client/MonoTorrent.Client/Managers/PeerExchangeManager.cs b/src/MonoTorrent.Client/MonoTorrent.Client/Managers/PeerExchangeManager.cs
@@ -93,9 +93,13 @@ internal void OnTick ()
             var added = memory.Slice (0, len * 6);
             var addedDotF = memory.Slice (added.Length, len);
 
+            int stride = 6;
+
             for (int i = 0; i < len; i++) {
                 var peer = addedPeers.Dequeue ();
-                peer.Peer.CompactPeer (added.Span.Slice (i * 6, 6));
+                if (!peer.Peer.TryWriteCompactPeer (added.Span.Slice (i * stride, stride), out int written) || written != stride)
+                    throw new NotSupportedException ();
+
                 if (EncryptionTypes.SupportsRC4 (peer.Peer.AllowedEncryption)) {
                     addedDotF.Span[i] = 0x01;
                 } else {
@@ -107,16 +111,17 @@ internal void OnTick ()
 
             // The remainder of our buffer can be filled with dropped peers.
             // We do some math to slice the remainder of the original memory
-            // buffer to an even multiple of 6. Then we calculate how many
+            // buffer to an even multiple of 'stride'. Then we calculate how many
             // peers we actually want to put in it, and then we slice it one
             // more time if we don't have enough dropped peers.
             var dropped = memory.Slice (added.Length + addedDotF.Length);
-            dropped = dropped.Slice (0, (dropped.Length / 6) * 6);
-            len = Math.Min (dropped.Length / 6, droppedPeers.Count);
-            dropped = dropped.Slice (0, len * 6);
+            dropped = dropped.Slice (0, (dropped.Length / stride) * stride);
+            len = Math.Min (dropped.Length / stride, droppedPeers.Count);
+            dropped = dropped.Slice (0, len * stride);
 
             for (int i = 0; i < len; i++)
-                droppedPeers.Dequeue ().Peer.CompactPeer (dropped.Span.Slice (i * 6, 6));
+                if (!droppedPeers.Dequeue ().Peer.TryWriteCompactPeer (dropped.Span.Slice (i * stride, stride), out int written) || written != stride)
+                    throw new NotSupportedException ();
 
             (var message, var releaser) = PeerMessage.Rent<PeerExchangeMessage> ();
             message.Initialize (new ExtensionSupports (new[] { PeerExchangeMessage.Support }), added, addedDotF, dropped, memoryReleaser);

diff --git a/src/MonoTorrent.Client/MonoTorrent.Client/Peers/Peer.cs b/src/MonoTorrent.Client/MonoTorrent.Client/Peers/Peer.cs
@@ -130,8 +130,8 @@ public override string ToString ()
         internal byte[] CompactPeer ()
             => Info.CompactPeer ();
 
-        internal void CompactPeer (Span<byte> buffer)
-            => Info.CompactPeer (buffer);
+        internal bool TryWriteCompactPeer (Span<byte> buffer, out int written)
+            => Info.TryWriteCompactPeer (buffer, out written);
 
         internal static BEncodedList Encode (IEnumerable<Peer> peers)
         {

diff --git a/src/MonoTorrent.Client/MonoTorrent.Client/Peers/PeerDecoder.cs b/src/MonoTorrent.Client/MonoTorrent.Client/Peers/PeerDecoder.cs
@@ -29,22 +29,23 @@
 
 using System;
 using System.Collections.Generic;
+using System.Net.Sockets;
 
 using MonoTorrent.BEncoding;
 
 namespace MonoTorrent
 {
     static class PeerDecoder
     {
-        public static IList<PeerInfo> Decode (BEncodedList peers)
+        public static IList<PeerInfo> Decode (BEncodedList peers, AddressFamily addressFamily)
         {
             var list = new List<PeerInfo> (peers.Count);
             foreach (BEncodedValue value in peers) {
                 try {
-                    if (value is BEncodedDictionary)
-                        list.Add (DecodeFromDict ((BEncodedDictionary) value));
-                    else if (value is BEncodedString)
-                        foreach (PeerInfo p in Decode ((BEncodedString) value))
+                    if (value is BEncodedDictionary dict)
+                        list.Add (DecodeFromDict (dict));
+                    else if (value is BEncodedString str)
+                        foreach (var p in PeerInfo.FromCompact (str.Span, addressFamily))
                             list.Add (p);
                 } catch {
                     // If something is invalid and throws an exception, ignore it
@@ -73,8 +74,5 @@ static PeerInfo DecodeFromDict (BEncodedDictionary dict)
             var connectionUri = new Uri ($"ipv4://{dict[IPKey]}:{dict[PortKey]}");
             return new PeerInfo (connectionUri, peerId);
         }
-
-        public static IList<PeerInfo> Decode (BEncodedString peers)
-            => PeerInfo.FromCompact (peers.Span);
     }
 }
diff --git a/src/MonoTorrent.Dht/MonoTorrent.Dht.Tasks/GetPeersTask.cs b/src/MonoTorrent.Dht/MonoTorrent.Dht.Tasks/GetPeersTask.cs
@@ -84,7 +84,7 @@ public async Task<IEnumerable<Node>> ExecuteAsync ()
                 // The response had some actual peers
                 if (response.Values != null) {
                     // We have actual peers!
-                    var peers = response.Values.OfType<BEncodedString> ().SelectMany (t => PeerInfo.FromCompact (t.Span)).ToArray ();
+                    var peers = response.Values.OfType<BEncodedString> ().SelectMany (t => PeerInfo.FromCompact (t.Span, Engine.AddressFamily)).ToArray ();
                     Engine.RaisePeersFound (InfoHash, peers);
                     foreach (var peer in peers)
                         FoundPeers.Add (peer);

diff --git a/src/MonoTorrent.Dht/MonoTorrent.Dht/DhtEngine.cs b/src/MonoTorrent.Dht/MonoTorrent.Dht/DhtEngine.cs
@@ -30,6 +30,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Net.Sockets;
 using System.Security.Cryptography;
 using System.Threading.Tasks;
 
@@ -74,6 +75,9 @@ public class DhtEngine : IDisposable, IDhtEngine
 
         internal static MainLoop MainLoop { get; } = new MainLoop ("DhtLoop");
 
+        // IPV6 - create an IPV4 and an IPV6 dht engine
+        public AddressFamily AddressFamily { get; private set; } = AddressFamily.InterNetwork;
+
         public TimeSpan AnnounceInterval => DefaultAnnounceInternal;
 
         public bool Disposed { get; private set; }

diff --git a/src/MonoTorrent.Trackers/MonoTorrent.Client.Messages.UdpTracker/AnnounceResponseMessage.cs b/src/MonoTorrent.Trackers/MonoTorrent.Client.Messages.UdpTracker/AnnounceResponseMessage.cs
@@ -29,26 +29,34 @@
 
 using System;
 using System.Collections.Generic;
+using System.Net.Sockets;
 
 namespace MonoTorrent.Messages.UdpTracker
 {
     public class AnnounceResponseMessage : UdpTrackerMessage
     {
-        public override int ByteLength => (4 * 5 + Peers.Count * 6);
+        public AddressFamily AddressFamily { get; private set; }
+        public override int ByteLength => (4 * 5 + Peers.Count * Stride);
         public TimeSpan Interval { get; private set; }
         public int Leechers { get; private set; }
         public List<PeerInfo> Peers { get; private set; }
         public int Seeders { get; private set; }
+        int Stride => AddressFamily switch {
+            AddressFamily.InterNetwork => 6,
+            AddressFamily.InterNetworkV6 => 18,
+            _ => throw new NotSupportedException ()
+        };
 
-        public AnnounceResponseMessage ()
-            : this (0, TimeSpan.Zero, 0, 0, new List<PeerInfo> ())
+        public AnnounceResponseMessage (AddressFamily addressFamily)
+            : this (addressFamily, 0, TimeSpan.Zero, 0, 0, new List<PeerInfo> ())
         {
 
         }
 
-        public AnnounceResponseMessage (int transactionId, TimeSpan interval, int leechers, int seeders, List<PeerInfo> peers)
+        public AnnounceResponseMessage (AddressFamily addressFamily, int transactionId, TimeSpan interval, int leechers, int seeders, List<PeerInfo> peers)
             : base (1, transactionId)
         {
+            AddressFamily = addressFamily;
             Interval = interval;
             Leechers = leechers;
             Peers = peers;
@@ -64,7 +72,7 @@ public override void Decode (ReadOnlySpan<byte> buffer)
             Leechers = ReadInt (ref buffer);
             Seeders = ReadInt (ref buffer);
 
-            IList<PeerInfo> peers = PeerInfo.FromCompact (buffer);
+            IList<PeerInfo> peers = PeerInfo.FromCompact (buffer, AddressFamily);
             Peers.AddRange (peers);
         }
 
@@ -79,7 +87,8 @@ public override int Encode (Span<byte> buffer)
             Write (ref buffer, Seeders);
 
             for (int i = 0; i < Peers.Count; i++)
-                Peers[i].CompactPeer (buffer.Slice (i * 6));
+                if (!Peers[i].TryWriteCompactPeer (buffer.Slice (i * Stride, Stride), out int dataWritten) || dataWritten != Stride)
+                    throw new InvalidOperationException ();
 
             return written - buffer.Length;
         }

diff --git a/src/MonoTorrent.Trackers/MonoTorrent.Client.Messages.UdpTracker/UdpTrackerMessage.cs b/src/MonoTorrent.Trackers/MonoTorrent.Client.Messages.UdpTracker/UdpTrackerMessage.cs
@@ -28,6 +28,7 @@
 
 
 using System;
+using System.Net.Sockets;
 
 namespace MonoTorrent.Messages.UdpTracker
 {
@@ -42,7 +43,7 @@ protected UdpTrackerMessage (int action, int transactionId)
             TransactionId = transactionId;
         }
 
-        public static UdpTrackerMessage DecodeMessage (ReadOnlySpan<byte> buffer, MessageType type)
+        public static UdpTrackerMessage DecodeMessage (ReadOnlySpan<byte> buffer, MessageType type, AddressFamily addressFamily)
         {
             UdpTrackerMessage m;
             var actionBuffer = type == MessageType.Request ? buffer.Slice (8) : buffer;
@@ -58,7 +59,7 @@ public static UdpTrackerMessage DecodeMessage (ReadOnlySpan<byte> buffer, Messag
                     if (type == MessageType.Request)
                         m = new AnnounceMessage ();
                     else
-                        m = new AnnounceResponseMessage ();
+                        m = new AnnounceResponseMessage (addressFamily);
                     break;
                 case 2:
                     if (type == MessageType.Request)

diff --git a/src/MonoTorrent.Trackers/MonoTorrent.Connections.Tracker/HTTPTrackerConnection.cs b/src/MonoTorrent.Trackers/MonoTorrent.Connections.Tracker/HTTPTrackerConnection.cs
@@ -33,6 +33,7 @@
 using System.IO;
 using System.Linq;
 using System.Net.Http;
+using System.Net.Sockets;
 using System.Threading;
 using System.Threading.Tasks;
 
@@ -52,6 +53,8 @@ public class HttpTrackerConnection : ITrackerConnection
 
         static readonly Random random = new Random ();
 
+        public AddressFamily AddressFamily { get; }
+
         public bool CanScrape { get; }
 
         public Uri? ScrapeUri { get; }
@@ -69,7 +72,14 @@ public class HttpTrackerConnection : ITrackerConnection
         HttpClient Client { get; }
 
         public HttpTrackerConnection (Uri announceUri, HttpClient client)
+            : this(announceUri, client, AddressFamily.InterNetwork)
+        {
+
+        }
+
+        public HttpTrackerConnection (Uri announceUri, HttpClient client, AddressFamily addressFamily)
         {
+            AddressFamily = addressFamily;
             Uri = announceUri;
             Client = client;
 
@@ -282,9 +292,9 @@ AnnounceResponse HandleAnnounce (InfoHash infoHash, BEncodedDictionary dict)
 
                     case ("peers"):
                         if (keypair.Value is BEncodedList bencodedList)          // Non-compact response
-                            peers.AddRange (PeerDecoder.Decode (bencodedList));
+                            peers.AddRange (PeerDecoder.Decode (bencodedList, AddressFamily));
                         else if (keypair.Value is BEncodedString bencodedStr)   // Compact response
-                            peers.AddRange (PeerDecoder.Decode (bencodedStr));
+                            peers.AddRange (PeerInfo.FromCompact (bencodedStr.Span, AddressFamily));
                         break;
 
                     case ("failure reason"):

diff --git a/src/MonoTorrent.Trackers/MonoTorrent.Connections.Tracker/UdpTrackerConnection.cs b/src/MonoTorrent.Trackers/MonoTorrent.Connections.Tracker/UdpTrackerConnection.cs
@@ -188,7 +188,7 @@ async Task<long> ConnectAsync ()
         {
             while (!token.IsCancellationRequested) {
                 UdpReceiveResult received = await client.ReceiveAsync ();
-                var rsp = UdpTrackerMessage.DecodeMessage (received.Buffer.AsSpan (0, received.Buffer.Length), MessageType.Response);
+                var rsp = UdpTrackerMessage.DecodeMessage (received.Buffer.AsSpan (0, received.Buffer.Length), MessageType.Response, received.RemoteEndPoint.AddressFamily);
 
                 if (transactionId == rsp.TransactionId) {
                     if (rsp is ErrorMessage error) {

diff --git a/src/MonoTorrent.Trackers/MonoTorrent.Connections.TrackerServer/UdpTrackerListener.cs b/src/MonoTorrent.Trackers/MonoTorrent.Connections.TrackerServer/UdpTrackerListener.cs
@@ -104,7 +104,7 @@ async void ReceiveAsync (UdpClient client, CancellationToken token)
                     if (data.Length < 16)
                         return; //bad request
 
-                    var request = UdpTrackerMessage.DecodeMessage (data.AsSpan (0, data.Length), MessageType.Request);
+                    var request = UdpTrackerMessage.DecodeMessage (data.AsSpan (0, data.Length), MessageType.Request, result.RemoteEndPoint.AddressFamily);
 
                     if (sendTask != null) {
                         try {
@@ -180,16 +180,16 @@ protected virtual async Task ReceiveAnnounce (UdpClient client, AnnounceMessage
 
                         case ("peers"):
                             if (keypair.Value is BEncodedList)          // Non-compact response
-                                peers.AddRange (PeerDecoder.Decode ((BEncodedList) keypair.Value));
-                            else if (keypair.Value is BEncodedString)   // Compact response
-                                peers.AddRange (PeerDecoder.Decode ((BEncodedString) keypair.Value));
+                                peers.AddRange (PeerDecoder.Decode ((BEncodedList) keypair.Value, remotePeer.AddressFamily));
+                            else if (keypair.Value is BEncodedString str)   // Compact response
+                                peers.AddRange (PeerInfo.FromCompact (str.Span, remotePeer.AddressFamily));
                             break;
 
                         default:
                             break;
                     }
                 }
-                m = new AnnounceResponseMessage (announceMessage.TransactionId, interval, leechers, seeders, peers);
+                m = new AnnounceResponseMessage (remotePeer.AddressFamily, announceMessage.TransactionId, interval, leechers, seeders, peers);
             }
             byte[] data = m.Encode ();
             await client.SendAsync (data, data.Length, remotePeer);

diff --git a/src/MonoTorrent/MonoTorrent.Connections.Peer/IPeerConnection.cs b/src/MonoTorrent/MonoTorrent.Connections.Peer/IPeerConnection.cs
@@ -29,6 +29,7 @@
 
 using System;
 using System.Net;
+using System.Net.Sockets;
 
 using ReusableTasks;
 

diff --git a/src/MonoTorrent/MonoTorrent.csproj b/src/MonoTorrent/MonoTorrent.csproj
@@ -2,6 +2,7 @@
 
   <PropertyGroup>
     <CheckEolTargetFramework>false</CheckEolTargetFramework>
+    <UseMemoryExtensions>true</UseMemoryExtensions>
     <TargetFrameworks>net6.0;net5.0;netcoreapp3.0;netstandard2.1;netstandard2.0</TargetFrameworks>
   </PropertyGroup>