From 0d36ea4c5d9c00c537e34502974ff620ca88ce42 Mon Sep 17 00:00:00 2001
From: Matt Joiner <anacrolix@gmail.com>
Date: Fri, 11 Jul 2025 00:12:12 +1000
Subject: [PATCH] Add DialForPeerConns config option so you can disable peer
 conns

---
 client.go        | 21 ++++++++++++++++++---
 config.go        |  3 +++
 issue211_test.go |  1 +
 3 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/client.go b/client.go
index 8f856827..442b7138 100644
--- a/client.go
+++ b/client.go
@@ -325,11 +325,12 @@ func NewClient(cfg *ClientConfig) (cl *Client, err error) {
 	// Check for panics.
 	cl.LocalPort()
 
-	for _, _s := range sockets {
-		s := _s // Go is fucking retarded.
+	for _, s := range sockets {
 		cl.onClose = append(cl.onClose, func() { go s.Close() })
 		if peerNetworkEnabled(parseNetworkString(s.Addr().Network()), cl.config) {
-			cl.dialers = append(cl.dialers, s)
+			if cl.config.DialForPeerConns {
+				cl.dialers = append(cl.dialers, s)
+			}
 			cl.listeners = append(cl.listeners, s)
 			if cl.config.AcceptPeerConnections {
 				go cl.acceptConnections(s)
@@ -390,6 +391,7 @@ func NewClient(cfg *ClientConfig) (cl *Client, err error) {
 
 	cl.webseedRequestTimer = time.AfterFunc(webseedRequestUpdateTimerInterval, cl.updateWebseedRequestsTimerFunc)
 
+	err = cl.checkConfig()
 	return
 }
 
@@ -1927,3 +1929,16 @@ func (cl *Client) underWebSeedHttpRequestLimit(key webseedHostKeyHandle) bool {
 	panicif.Zero(key)
 	return cl.numWebSeedRequests[key] < defaultRequestsPerWebseedHost
 }
+
+// Check for bad arrangements. This is a candidate for an error state check method.
+func (cl *Client) checkConfig() error {
+	if cl.config.DownloadRateLimiter.Limit() == 0 {
+		if len(cl.dialers) != 0 {
+			return errors.New("download rate limit is zero, but dialers are set")
+		}
+		if len(cl.listeners) != 0 && cl.config.AcceptPeerConnections {
+			return errors.New("download rate limit is zero, but listening for peer connections")
+		}
+	}
+	return nil
+}
diff --git a/config.go b/config.go
index e0727865..55b72ade 100644
--- a/config.go
+++ b/config.go
@@ -171,6 +171,8 @@ type ClientConfig struct {
 	// bit of a special case, since a peer could also be useless if they're just not interested, or
 	// we don't intend to obtain all of a torrent's data.
 	DropMutuallyCompletePeers bool
+	// Use dialers to obtain connections to regular peers.
+	DialForPeerConns bool
 	// Whether to accept peer connections at all.
 	AcceptPeerConnections bool
 	// Whether a Client should want conns without delegating to any attached Torrents. This is
@@ -239,6 +241,7 @@ func NewDefaultClientConfig() *ClientConfig {
 		CryptoProvides:         mse.AllSupportedCrypto,
 		ListenPort:             42069,
 		Extensions:             defaultPeerExtensionBytes(),
+		DialForPeerConns:       true,
 		AcceptPeerConnections:  true,
 		MaxUnverifiedBytes:     64 << 20,
 		DialRateLimiter:        rate.NewLimiter(10, 10),
diff --git a/issue211_test.go b/issue211_test.go
index 914db687..d8c541da 100644
--- a/issue211_test.go
+++ b/issue211_test.go
@@ -20,6 +20,7 @@ func TestDropTorrentWithMmapStorageWhileHashing(t *testing.T) {
 	// Ensure the data is present when the torrent is added, and not obtained
 	// over the network as the test runs.
 	cfg.DownloadRateLimiter = rate.NewLimiter(0, 0)
+	cfg.DialForPeerConns = false
 	cl, err := NewClient(cfg)
 	require.NoError(t, err)
 	defer cl.Close()
-- 
2.51.0