From 2abf42515b41f9f996cc683096af9ed0d5c85fce Mon Sep 17 00:00:00 2001
From: Cthulhu-throwaway <96153783+Cthulhu-throwaway@users.noreply.github.com>
Date: Wed, 1 Jun 2022 03:24:46 -0300
Subject: [PATCH] (UPnP) Fix for zero-length datagrams

---
 network/natt.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/network/natt.c b/network/natt.c
index cf5be9ebfd..92736c6d3a 100644
--- a/network/natt.c
+++ b/network/natt.c
@@ -194,8 +194,12 @@ bool natt_device_next(struct natt_discovery *discovery,
 
    recvd = recvfrom(discovery->fd, buf, sizeof(buf), 0,
       (struct sockaddr *) &device->addr, &addr_size);
-   if (recvd <= 0)
+   if (recvd < 0)
       return false;
+   /* Zero-length datagrams are valid, but we can't do anything with them.
+      Don't treat them as an error. */
+   if (!recvd)
+      return true;
 
    /* Parse the data we received.
       We are only looking for the 'Location' HTTP header. */