Set a minimum dial timeout

client.go

@@ -394,8 +394,12 @@ func doDial(dial func() (net.Conn, error), ch chan dialResult, utp bool) {
 	}
 }
 
-func reducedDialTimeout(max time.Duration, halfOpenLimit int, pendingPeers int) time.Duration {
-	return max / time.Duration((pendingPeers+halfOpenLimit)/halfOpenLimit)
+func reducedDialTimeout(max time.Duration, halfOpenLimit int, pendingPeers int) (ret time.Duration) {
+	ret = max / time.Duration((pendingPeers+halfOpenLimit)/halfOpenLimit)
+	if ret < minDialTimeout {
+		ret = minDialTimeout
+	}
+	return
 }
 
 // Start the process of connecting to the given peer for the given torrent if
@@ -409,7 +413,7 @@ func (me *Client) initiateConn(peer Peer, t *torrent) {
 		duplicateConnsAvoided.Add(1)
 		return
 	}
-	dialTimeout := reducedDialTimeout(dialTimeout, me.halfOpenLimit, len(t.Peers))
+	dialTimeout := reducedDialTimeout(nominalDialTimeout, me.halfOpenLimit, len(t.Peers))
 	t.HalfOpen[addr] = struct{}{}
 	go func() {
 		// Binding to the listen address and dialing via net.Dialer gives

client_test.go

@@ -84,15 +84,19 @@ func TestReducedDialTimeout(t *testing.T) {
 		PendingPeers    int
 		ExpectedReduced time.Duration
 	}{
-		{dialTimeout, 40, 0, dialTimeout},
-		{dialTimeout, 40, 1, dialTimeout},
-		{dialTimeout, 40, 39, dialTimeout},
-		{dialTimeout, 40, 40, dialTimeout / 2},
-		{dialTimeout, 40, 80, dialTimeout / 3},
-		{dialTimeout, 40, 4000, dialTimeout / 101},
+		{nominalDialTimeout, 40, 0, nominalDialTimeout},
+		{nominalDialTimeout, 40, 1, nominalDialTimeout},
+		{nominalDialTimeout, 40, 39, nominalDialTimeout},
+		{nominalDialTimeout, 40, 40, nominalDialTimeout / 2},
+		{nominalDialTimeout, 40, 80, nominalDialTimeout / 3},
+		{nominalDialTimeout, 40, 4000, nominalDialTimeout / 101},
 	} {
 		reduced := reducedDialTimeout(_case.Max, _case.HalfOpenLimit, _case.PendingPeers)
-		if reduced != _case.ExpectedReduced {
+		expected := _case.ExpectedReduced
+		if expected < minDialTimeout {
+			expected = minDialTimeout
+		}
+		if reduced != expected {
 			t.Fatalf("expected %s, got %s", _case.ExpectedReduced, reduced)
 		}
 	}

misc.go

@@ -15,11 +15,12 @@ import (
 )
 
 const (
-	pieceHash   = crypto.SHA1
-	maxRequests = 250        // Maximum pending requests we allow peers to send us.
-	chunkSize   = 0x4000     // 16KiB
-	BEP20       = "-GT0000-" // Peer ID client identifier prefix
-	dialTimeout = time.Second * 30
+	pieceHash          = crypto.SHA1
+	maxRequests        = 250        // Maximum pending requests we allow peers to send us.
+	chunkSize          = 0x4000     // 16KiB
+	BEP20              = "-GT0000-" // Peer ID client identifier prefix
+	nominalDialTimeout = time.Second * 30
+	minDialTimeout     = 5 * time.Second
 )
 
 type (
@@ -156,6 +157,7 @@ func mmapTorrentData(md *metainfo.Info, location string) (mms mmap_span.MMapSpan
 	return
 }
 
+// The size in bytes of a metadata extension piece.
 func metadataPieceSize(totalSize int, piece int) int {
 	ret := totalSize - piece*(1<<14)
 	if ret > 1<<14 {