From 30e1ceef303dc02c0494f71774d0848485da4c8e Mon Sep 17 00:00:00 2001
From: "Steinar H. Gunderson" <sgunderson@bigfoot.com>
Date: Wed, 16 Oct 2019 18:56:14 +0200
Subject: [PATCH] Allow (and forward) zero-byte UDP packets.

---
 udpinput.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/udpinput.cpp b/udpinput.cpp
index a2915e8..4b421a3 100644
--- a/udpinput.cpp
+++ b/udpinput.cpp
@@ -210,7 +210,7 @@ void UDPInput::do_work()
 			ret = recv(sock, packet_buf, sizeof(packet_buf), 0);
 		} while (ret == -1 && errno == EINTR);
 
-		if (ret <= 0) {
+		if (ret < 0) {  // Note that zero-byte packets are legal.
 			log_perror("recv");
 			close_socket();
 			continue;
-- 
2.39.2