From: Matt Joiner <anacrolix@gmail.com>
Date: Tue, 9 Dec 2014 03:58:49 +0000 (-0600)
Subject: Add pending peers high water mark to stop excessively long running DHT queries
X-Git-Tag: v1.0.0~1398
X-Git-Url: http://www.git.stargrave.org/?a=commitdiff_plain;h=48582796ed80c4a7ebb714d3160de0288bdff5fa;p=btrtrc.git

Add pending peers high water mark to stop excessively long running DHT queries
---

diff --git a/client.go b/client.go
index f0315762..aeff48c0 100644
--- a/client.go
+++ b/client.go
@@ -76,7 +76,9 @@ const (
 	// DHT: http://www.bittorrent.org/beps/bep_0005.html
 	extensionBytes = "\x00\x00\x00\x00\x00\x10\x00\x01"
 
-	socketsPerTorrent = 40
+	socketsPerTorrent     = 40
+	torrentPeersHighWater = 1000
+	torrentPeersLowWater  = socketsPerTorrent * 5
 )
 
 // Currently doesn't really queue, but should in the future.
@@ -1451,14 +1453,7 @@ func (me *Client) openNewConns(t *torrent) {
 	t.wantPeers.Broadcast()
 }
 
-// Adds peers to the swarm for the torrent corresponding to infoHash.
-func (me *Client) AddPeers(infoHash InfoHash, peers []Peer) error {
-	me.mu.Lock()
-	defer me.mu.Unlock()
-	t := me.torrent(infoHash)
-	if t == nil {
-		return errors.New("no such torrent")
-	}
+func (me *Client) addPeers(t *torrent, peers []Peer) {
 	blocked := 0
 	for i, p := range peers {
 		if me.ipBlockRange(p.IP) == nil {
@@ -1474,6 +1469,17 @@ func (me *Client) AddPeers(infoHash InfoHash, peers []Peer) error {
 	}
 	t.AddPeers(peers)
 	me.openNewConns(t)
+}
+
+// Adds peers to the swarm for the torrent corresponding to infoHash.
+func (me *Client) AddPeers(infoHash InfoHash, peers []Peer) error {
+	me.mu.Lock()
+	defer me.mu.Unlock()
+	t := me.torrent(infoHash)
+	if t == nil {
+		return errors.New("no such torrent")
+	}
+	me.addPeers(t, peers)
 	return nil
 }
 
@@ -1783,7 +1789,7 @@ func (cl *Client) waitWantPeers(t *torrent) bool {
 			return false
 		default:
 		}
-		if len(t.Peers) < socketsPerTorrent*5 {
+		if len(t.Peers) < torrentPeersLowWater {
 			return true
 		}
 		cl.mu.Unlock()
@@ -1818,7 +1824,8 @@ func (cl *Client) announceTorrentDHT(t *torrent, impliedPort bool) {
 					}).String()] = struct{}{}
 				}
 				// log.Printf("%s: %d new peers from DHT", t, len(v.Peers))
-				err = cl.AddPeers(t.InfoHash, func() (ret []Peer) {
+				cl.mu.Lock()
+				cl.addPeers(t, func() (ret []Peer) {
 					for _, cp := range v.Peers {
 						ret = append(ret, Peer{
 							IP:     cp.IP[:],
@@ -1828,8 +1835,9 @@ func (cl *Client) announceTorrentDHT(t *torrent, impliedPort bool) {
 					}
 					return
 				}())
-				if err != nil {
-					log.Printf("error adding peers from dht for torrent %q: %s", t, err)
+				numPeers := len(t.Peers)
+				cl.mu.Unlock()
+				if numPeers >= torrentPeersHighWater {
 					break getPeers
 				}
 			case <-t.ceasingNetworking: