From af30b4d982f55cdac623466f5c5a9cb36a75556d Mon Sep 17 00:00:00 2001
From: Felix Lange <fjl@twurst.com>
Date: Sun, 9 Feb 2020 15:47:40 +0100
Subject: [PATCH] p2p: fix maxDialedConns for maxpeers < dialRatio

Always allocate at least one dial slot unless dialing is disabled using
NoDial or MaxPeers == 0. Most importantly, this fixes MaxPeers == 1 to
dedicate the sole slot to dialing instead of listening.
---
 p2p/server.go | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/p2p/server.go b/p2p/server.go
index 4545206363..1d4ac970a5 100644
--- a/p2p/server.go
+++ b/p2p/server.go
@@ -620,15 +620,19 @@ func (srv *Server) maxInboundConns() int {
 	return srv.MaxPeers - srv.maxDialedConns()
 }
 
-func (srv *Server) maxDialedConns() int {
-	if srv.NoDial {
+func (srv *Server) maxDialedConns() (limit int) {
+	if srv.NoDial || srv.MaxPeers == 0 {
 		return 0
 	}
-	r := srv.DialRatio
-	if r == 0 {
-		r = defaultDialRatio
+	if srv.DialRatio == 0 {
+		limit = srv.MaxPeers / defaultDialRatio
+	} else {
+		limit = srv.MaxPeers / srv.DialRatio
 	}
-	return srv.MaxPeers / r
+	if limit == 0 {
+		limit = 1
+	}
+	return limit
 }
 
 func (srv *Server) setupListening() error {