From a01b451857e2e0880d5315dbdd94547519b73cd7 Mon Sep 17 00:00:00 2001
From: Matt Joiner <anacrolix@gmail.com>
Date: Fri, 18 Jun 2021 14:59:20 +1000
Subject: [PATCH] Add ClientConfig.AcceptPeerConnections

---
 client.go | 10 +++++++---
 config.go | 11 +++++++----
 2 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/client.go b/client.go
index a8d93319..dc244807 100644
--- a/client.go
+++ b/client.go
@@ -248,7 +248,9 @@ func NewClient(cfg *ClientConfig) (cl *Client, err error) {
 		if peerNetworkEnabled(parseNetworkString(s.Addr().Network()), cl.config) {
 			cl.dialers = append(cl.dialers, s)
 			cl.listeners = append(cl.listeners, s)
-			go cl.acceptConnections(s)
+			if cl.config.AcceptPeerConnections {
+				go cl.acceptConnections(s)
+			}
 		}
 	}
 
@@ -322,12 +324,14 @@ func (cl *Client) Listeners() []Listener {
 // yourself.
 func (cl *Client) AddListener(l Listener) {
 	cl.listeners = append(cl.listeners, l)
-	go cl.acceptConnections(l)
+	if cl.config.AcceptPeerConnections {
+		go cl.acceptConnections(l)
+	}
 }
 
 func (cl *Client) firewallCallback(net.Addr) bool {
 	cl.rLock()
-	block := !cl.wantConns()
+	block := !cl.wantConns() || !cl.config.AcceptPeerConnections
 	cl.rUnlock()
 	if block {
 		torrent.Add("connections firewalled", 1)
diff --git a/config.go b/config.go
index b687f05d..b952ca95 100644
--- a/config.go
+++ b/config.go
@@ -133,6 +133,8 @@ 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
+	// Whether to accept peer connections at all.
+	AcceptPeerConnections bool
 
 	// OnQuery hook func
 	DHTOnQuery func(query *krpc.Msg, source net.Addr) (propagate bool)
@@ -180,10 +182,11 @@ func NewDefaultClientConfig() *ClientConfig {
 			Preferred:        true,
 			RequirePreferred: false,
 		},
-		CryptoSelector: mse.DefaultCryptoSelector,
-		CryptoProvides: mse.AllSupportedCrypto,
-		ListenPort:     42069,
-		Extensions:     defaultPeerExtensionBytes(),
+		CryptoSelector:        mse.DefaultCryptoSelector,
+		CryptoProvides:        mse.AllSupportedCrypto,
+		ListenPort:            42069,
+		Extensions:            defaultPeerExtensionBytes(),
+		AcceptPeerConnections: true,
 	}
 	//cc.ConnTracker.SetNoMaxEntries()
 	//cc.ConnTracker.Timeout = func(conntrack.Entry) time.Duration { return 0 }