From 23e8a558c28a767a3e7db7156b9aac9eeb0e12e9 Mon Sep 17 00:00:00 2001
From: zzz <zzz>
Date: Sat, 16 Sep 2006 21:07:28 +0000
Subject: [PATCH] (zzz)     * i2psnark: Implement retransmission of requests.
 This       eliminates one cause of complete stalls with a peer.       This
 problem is common on torrents with a small number of       active peers where
 there are no choke/unchokes to kickstart things.

---
 .../java/src/org/klomp/snark/Peer.java        | 10 ++++++++++
 .../src/org/klomp/snark/PeerCheckerTask.java  |  1 +
 .../org/klomp/snark/PeerConnectionOut.java    | 20 +++++++++++++++++++
 .../java/src/org/klomp/snark/PeerState.java   |  6 ++++++
 .../java/src/org/klomp/snark/Request.java     |  1 +
 history.txt                                   |  8 +++++++-
 .../src/net/i2p/router/RouterVersion.java     |  4 ++--
 7 files changed, 47 insertions(+), 3 deletions(-)

diff --git a/apps/i2psnark/java/src/org/klomp/snark/Peer.java b/apps/i2psnark/java/src/org/klomp/snark/Peer.java
index 39572fb3a8..7d066b150c 100644
--- a/apps/i2psnark/java/src/org/klomp/snark/Peer.java
+++ b/apps/i2psnark/java/src/org/klomp/snark/Peer.java
@@ -477,4 +477,14 @@ public class Peer implements Comparable
       s.keepAlive();
   }
 
+  /**
+   * Retransmit outstanding requests if necessary
+   */
+  public void retransmitRequests()
+  {
+    PeerState s = state;
+    if (s != null)
+      s.retransmitRequests();
+  }
+
 }
diff --git a/apps/i2psnark/java/src/org/klomp/snark/PeerCheckerTask.java b/apps/i2psnark/java/src/org/klomp/snark/PeerCheckerTask.java
index 1efb25b4c2..2e0fdf9bae 100644
--- a/apps/i2psnark/java/src/org/klomp/snark/PeerCheckerTask.java
+++ b/apps/i2psnark/java/src/org/klomp/snark/PeerCheckerTask.java
@@ -164,6 +164,7 @@ class PeerCheckerTask extends TimerTask
                     worstDownloader = peer;
                   }
               }
+            peer.retransmitRequests();
             peer.keepAlive();
           }
 
diff --git a/apps/i2psnark/java/src/org/klomp/snark/PeerConnectionOut.java b/apps/i2psnark/java/src/org/klomp/snark/PeerConnectionOut.java
index ede9151583..bdebaa53ff 100644
--- a/apps/i2psnark/java/src/org/klomp/snark/PeerConnectionOut.java
+++ b/apps/i2psnark/java/src/org/klomp/snark/PeerConnectionOut.java
@@ -324,6 +324,23 @@ class PeerConnectionOut implements Runnable
     addMessage(m);
   }
 
+  /** reransmit requests not received in 7m */
+  private static final int REQ_TIMEOUT = (2 * SEND_TIMEOUT) + (60 * 1000);
+  void retransmitRequests(List requests)
+  {
+    long now = System.currentTimeMillis();
+    Iterator it = requests.iterator();
+    while (it.hasNext())
+      {
+        Request req = (Request)it.next();
+        if(now > req.sendTime + REQ_TIMEOUT) {
+          if (_log.shouldLog(Log.DEBUG))
+              _log.debug("Retransmit request " + req + " to peer " + peer);
+          sendRequest(req);
+        }
+      }
+  }
+
   void sendRequests(List requests)
   {
     Iterator it = requests.iterator();
@@ -336,12 +353,15 @@ class PeerConnectionOut implements Runnable
 
   void sendRequest(Request req)
   {
+    // should we check for duplicate requests to deal with fibrillating i2p-bt??
+    // or just send some cancels when we get an unwanted chunk??
     Message m = new Message();
     m.type = Message.REQUEST;
     m.piece = req.piece;
     m.begin = req.off;
     m.length = req.len;
     addMessage(m);
+    req.sendTime = System.currentTimeMillis();
   }
 
   void sendPiece(int piece, int begin, int length, byte[] bytes)
diff --git a/apps/i2psnark/java/src/org/klomp/snark/PeerState.java b/apps/i2psnark/java/src/org/klomp/snark/PeerState.java
index e37dfb1a3c..ae4828d8d3 100644
--- a/apps/i2psnark/java/src/org/klomp/snark/PeerState.java
+++ b/apps/i2psnark/java/src/org/klomp/snark/PeerState.java
@@ -596,4 +596,10 @@ class PeerState
   {
         out.sendAlive();
   }
+
+  synchronized void retransmitRequests()
+  {
+      if (interesting && !choked)
+        out.retransmitRequests(outstandingRequests);
+  }
 }
diff --git a/apps/i2psnark/java/src/org/klomp/snark/Request.java b/apps/i2psnark/java/src/org/klomp/snark/Request.java
index 2a07a42893..2560b761d6 100644
--- a/apps/i2psnark/java/src/org/klomp/snark/Request.java
+++ b/apps/i2psnark/java/src/org/klomp/snark/Request.java
@@ -29,6 +29,7 @@ class Request
   final byte[] bs;
   final int off;
   final int len;
+  long sendTime;
 
   /**
    * Creates a new Request.
diff --git a/history.txt b/history.txt
index 0775aea60c..5279202b90 100644
--- a/history.txt
+++ b/history.txt
@@ -1,4 +1,10 @@
-$Id: history.txt,v 1.520 2006-09-13 18:24:14 zzz Exp $
+$Id: history.txt,v 1.521 2006-09-13 21:37:33 zzz Exp $
+
+2006-09-16  zzz
+    * i2psnark: Implement retransmission of requests. This
+      eliminates one cause of complete stalls with a peer.
+      This problem is common on torrents with a small number of
+      active peers where there are no choke/unchokes to kickstart things.
 
 2006-09-13  zzz
     * i2psnark: Fix restoral of partial pieces broken by last patch
diff --git a/router/java/src/net/i2p/router/RouterVersion.java b/router/java/src/net/i2p/router/RouterVersion.java
index 6e3147286c..9d495afeb0 100644
--- a/router/java/src/net/i2p/router/RouterVersion.java
+++ b/router/java/src/net/i2p/router/RouterVersion.java
@@ -15,9 +15,9 @@ import net.i2p.CoreVersion;
  *
  */
 public class RouterVersion {
-    public final static String ID = "$Revision: 1.457 $ $Date: 2006-09-13 18:02:07 $";
+    public final static String ID = "$Revision: 1.458 $ $Date: 2006-09-13 21:37:32 $";
     public final static String VERSION = "0.6.1.25";
-    public final static long BUILD = 4;
+    public final static long BUILD = 5;
     public static void main(String args[]) {
         System.out.println("I2P Router version: " + VERSION + "-" + BUILD);
         System.out.println("Router ID: " + RouterVersion.ID);