rule: do not crash if to-be-printed flowtable lacks priority

Print an empty flowtable rather than crashing when dereferencing
flowtable->priority.expr (its NULL).

Signed-off-by: Florian Westphal <fw@strlen.de>

1 files changed, 6 insertions, 0 deletions

diff --git a/tests/shell/testcases/bogons/flowtable-no-priority-crash b/tests/shell/testcases/bogons/flowtable-no-priority-crash
new file mode 100644
index 00000000..b327a2bd
--- /dev/null
+++ b/tests/shell/testcases/bogons/flowtable-no-priority-crash
@@ -0,0 +1,6 @@
+reset rules
+table inet filter {
+	flowtable f {
+		devices = { lo }
+	}
+}