when deciding which peers to try to connect to, add some weights to punish peers that don't transfer piece data with us. We'll still give them another, but at longer intervals than better peers get.

libtransmission/peer-mgr.c

@@ -97,6 +97,7 @@ struct peer_atom
     uint8_t flags; /* these match the added_f flags */
     uint8_t myflags; /* flags that aren't defined in added_f */
     uint16_t port;
+    uint16_t numFails;
     struct in_addr addr;
     time_t time;
 };
@@ -290,12 +291,6 @@ getExistingAtom( const Torrent * t, const struct in_addr * addr )
     return tr_ptrArrayFindSorted( t->pool, addr, comparePeerAtomToAddress );
 }
 
-static int
-peerIsKnown( const Torrent * t, const struct in_addr * addr )
-{
-    return getExistingAtom( t, addr ) != NULL;
-}
-
 static int
 peerIsInUse( const Torrent * ct, const struct in_addr * addr )
 {
@@ -852,16 +847,19 @@ msgsCallbackFunc( void * vpeer, void * vevent, void * vt )
 static void
 ensureAtomExists( Torrent * t, const struct in_addr * addr, uint16_t port, uint8_t flags, uint8_t from )
 {
-    if( !peerIsKnown( t, addr ) )
+    struct peer_atom * a = getExistingAtom( t, addr );
+
+    if( a != NULL )
     {
         struct peer_atom * a = tr_new0( struct peer_atom, 1 );
         a->addr = *addr;
         a->port = port;
         a->flags = flags;
-        a->from = from;
         tordbg( t, "got a new atom: %s", tr_peerIoAddrStr(&a->addr,a->port) );
         tr_ptrArrayInsertSorted( t->pool, a, comparePeerAtoms );
     }
+
+    a->from = from;
 }
 
 /* FIXME: this is kind of a mess. */
@@ -906,6 +904,9 @@ myHandshakeDoneCB( tr_handshake    * handshake,
     if( !ok || !t || !t->isRunning )
     {
         tr_peerIoFree( io );
+
+        if( t )
+            ++getExistingAtom( t, in_addr )->numFails;
     }
     else /* looking good */
     {
@@ -976,7 +977,7 @@ tr_peerMgrAddIncoming( tr_peerMgr      * manager,
 void
 tr_peerMgrAddPex( tr_peerMgr     * manager,
                   const uint8_t  * torrentHash,
-                  int              from,
+                  uint8_t          from,
                   const tr_pex   * pex,
                   int              pexCount )
 {
@@ -995,7 +996,7 @@ tr_peerMgrAddPex( tr_peerMgr     * manager,
 void
 tr_peerMgrAddPeers( tr_peerMgr    * manager,
                     const uint8_t * torrentHash,
-                    int             from,
+                    uint8_t         from,
                     const uint8_t * peerCompact,
                     int             peerCount )
 {
@@ -1582,6 +1583,7 @@ getPeerCandidates( Torrent * t, int * setmeSize )
     ret = tr_new( struct peer_atom*, atomCount );
     for( i=retCount=0; i<atomCount; ++i )
     {
+        int wait, minWait, maxWait;
         struct peer_atom * atom = atoms[i];
 
         /* peer fed us too much bad data ... we only keep it around
@@ -1607,9 +1609,14 @@ getPeerCandidates( Torrent * t, int * setmeSize )
         }
 
         /* if we used this peer recently, give someone else a turn */
-        if( ( now - atom->time ) < 180 ) {
+        minWait = 60;
-            tordbg( t, "RECONNECT peer %d (%s) is in its grace period..",
+        maxWait = minWait * 5;
-                    i, tr_peerIoAddrStr(&atom->addr,atom->port) );
+        wait = atom->numFails * 10;
+        if( wait < minWait ) wait = minWait;
+        if( wait > maxWait ) wait = maxWait;
+        if( ( now - atom->time ) < wait ) {
+            tordbg( t, "RECONNECT peer %d (%s) is in its grace period of %d seconds..",
+                    i, tr_peerIoAddrStr(&atom->addr,atom->port), wait );
             continue;
         }
 
@@ -1646,9 +1653,19 @@ reconnectPulse( void * vtorrent )
                        tr_ptrArraySize(t->pool),
                        (int)MAX_RECONNECTIONS_PER_PULSE );
 
-        /* disconnect some peers */
+        /* disconnect some peers.
-        for( i=0; i<nBad; ++i )
+           if we got transferred piece data, then they might be good peers,
-            removePeer( t, connections[i] );
+           so reset their `numFails' weight to zero.  otherwise we connected
+           to them fruitlessly, so mark it as another fail */
+        for( i=0; i<nBad; ++i ) {
+            tr_peer * peer = connections[i];
+            struct peer_atom * atom = getExistingAtom( t, &peer->in_addr );
+            if( peer->pieceDataActivityDate )
+                atom->numFails = 0;
+            else
+                ++atom->numFails;
+            removePeer( t, peer );
+        }
 
         /* add some new ones */
         nAdd = MAX_CONNECTED_PEERS_PER_TORRENT - peerCount;

libtransmission/peer-mgr.h

@@ -43,13 +43,13 @@ void tr_peerMgrAddIncoming( tr_peerMgr      * manager,
 
 void tr_peerMgrAddPeers( tr_peerMgr     * manager,
                          const uint8_t  * torrentHash,
-                         int              from,
+                         uint8_t          from,
                          const uint8_t  * peerCompact,
                          int              peerCount );
 
 void tr_peerMgrAddPex( tr_peerMgr     * manager,
                        const uint8_t  * torrentHash,
-                       int              from,
+                       uint8_t          from,
                        const tr_pex   * pex,
                        int              pexCount );