From 657868e27ce72cade2af7c892b0e141ae0ed2a88 Mon Sep 17 00:00:00 2001
From: Chris Schinnerl <chris@sia.tech>
Date: Mon, 8 Jul 2024 08:41:04 +0200
Subject: [PATCH] syncer: resolve domain before checking if peer is banned

---
 syncer/syncer.go | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/syncer/syncer.go b/syncer/syncer.go
index e52c463..52a1080 100644
--- a/syncer/syncer.go
+++ b/syncer/syncer.go
@@ -360,10 +360,18 @@ func (s *Syncer) allowConnect(peer string, inbound bool) error {
 	if s.l == nil {
 		return errors.New("syncer is shutting down")
 	}
-	if banned, err := s.pm.Banned(peer); err != nil {
-		return err
-	} else if banned {
-		return ErrPeerBanned
+	addrs, err := (&net.Resolver{}).LookupIPAddr(s.shutdownCtx, peer)
+	if err != nil {
+		return fmt.Errorf("failed to resolve peer address: %w", err)
+	} else if len(addrs) == 0 {
+		return fmt.Errorf("peer didn't resolve to any addresses")
+	}
+	for _, addr := range addrs {
+		if banned, err := s.pm.Banned(addr.String()); err != nil {
+			return err
+		} else if banned {
+			return ErrPeerBanned
+		}
 	}
 	var in, out int
 	for _, p := range s.peers {