From: Matt Joiner <anacrolix@gmail.com>
Date: Sat, 29 Apr 2023 04:53:03 +0000 (+1000)
Subject: Don't dial out TCP from the listen port
X-Git-Tag: v1.51.0~30
X-Git-Url: http://www.git.stargrave.org/?a=commitdiff_plain;h=9624f6ff9ce2261a3f4b4bff25cea69b0c541a5f;p=btrtrc.git

Don't dial out TCP from the listen port
---

diff --git a/socket.go b/socket.go
index 22809e17..c1fb97fd 100644
--- a/socket.go
+++ b/socket.go
@@ -59,11 +59,10 @@ func listenTcp(network, address string) (s socket, err error) {
 		NetworkDialer: NetworkDialer{
 			Network: network,
 			Dialer: &net.Dialer{
-				// My hope is that dialling out from a consistent port will improve the
-				// hole-punching behaviour. It might also prevent duplicate connections to the same
-				// peer if the peer does the same thing. There should probably be a fallback dialer
-				// if we fail to configure the socket to reuse ports for whatever reason.
-				LocalAddr: l.Addr(),
+				// Dialling TCP from a local port limits us to a single outgoing TCP connection to
+				// each remote client. Instead this should be a last resort if we need to use holepunching, and only then to connect to other clients that actually try to holepunch TCP.
+				//LocalAddr: l.Addr(),
+
 				// We don't want fallback, as we explicitly manage the IPv4/IPv6 distinction
 				// ourselves, although it's probably not triggered as I think the network is already
 				// constrained to tcp4 or tcp6 at this point.