From e0a3291235230352148d5d30e51b341bfd9ad458 Mon Sep 17 00:00:00 2001
From: Joseph Henry <joseph-henry@users.noreply.github.com>
Date: Thu, 26 Jan 2023 10:26:12 -0800
Subject: [PATCH] Fix setMtu() on Linux. Add error checking (#1860)

* Fix setMtu() on Linux. Add error checking

* Slightly tweak ioctl MTU error message
---
 osdep/LinuxEthernetTap.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/osdep/LinuxEthernetTap.cpp b/osdep/LinuxEthernetTap.cpp
index 1192ffa90..8995b102b 100644
--- a/osdep/LinuxEthernetTap.cpp
+++ b/osdep/LinuxEthernetTap.cpp
@@ -553,8 +553,11 @@ void LinuxEthernetTap::setMtu(unsigned int mtu)
 		if (sock > 0) {
 			struct ifreq ifr;
 			memset(&ifr,0,sizeof(ifr));
+			strcpy(ifr.ifr_name,_dev.c_str());
 			ifr.ifr_ifru.ifru_mtu = (int)mtu;
-			ioctl(sock,SIOCSIFMTU,(void *)&ifr);
+			if (ioctl(sock,SIOCSIFMTU,(void *)&ifr) < 0) {
+				printf("WARNING: ioctl() failed updating existing Linux tap device (set MTU)\n");
+			}
 			close(sock);
 		}
 	}