From b493cf260439d7572abba4500f2f3deda96a0067 Mon Sep 17 00:00:00 2001
From: Johannes Truschnigg <johannes@truschnigg.info>
Date: Thu, 17 Mar 2022 20:09:29 +0100
Subject: [PATCH] Fix iface stats check, impl. cake SQM detection

---
 lagdetect.sh | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/lagdetect.sh b/lagdetect.sh
index bca7ffa..1e0936e 100755
--- a/lagdetect.sh
+++ b/lagdetect.sh
@@ -158,7 +158,7 @@ done
 
 for i in "${IFACE_RX}" "${IFACE_TX}"
 do
-  if ip link show "${i}" >/dev/null
+  if ! ip link show "${i}" >/dev/null
   then
     printf 'FATAL: Interface "%s" seems bogus\n' "${i}"
     exit 1
@@ -166,6 +166,18 @@ do
 done
 
 
+# XXX TODO add TX once/if egress SQM mgmt is implemented
+for i in "${IFACE_RX}"
+do
+  _qd="$(tc qdisc show dev "${i}" | awk '/^qdisc/{print $2}')"
+  if ! [ x"${_qd}" = xcake ]
+  then
+    printf 'FATAL: Interface "%s" does not seem to have cake SQM set up\n' "${i}"
+    exit 1
+  fi
+done
+
+
 set -u
 
 
-- 
2.39.5