xdp-forward: Add test for attaching to a high ifindex

Add a test that creates an interface with a high ifindex and verify that
xdp-forward can attach to it.

Signed-off-by: Toke Høiland-Jørgensen <[email protected]>

Author: tohojo

xdp-forward/tests/test-xdp-forward.sh

@@ -1,6 +1,6 @@
 XDP_LOADER=${XDP_LOADER:-./xdp-loader}
 XDP_FORWARD=${XDP_FORWARD:-./xdp-forward}
-ALL_TESTS="test_ping test_load test_fwd_full test_fwd_direct test_flowtable"
+ALL_TESTS="test_ping test_load test_load_high_ifindex test_fwd_full test_fwd_direct test_flowtable"
 
 test_ping()
 {
@@ -21,6 +21,19 @@ test_load()
     check_run $XDP_FORWARD unload ${NS_NAMES[@]}
 }
 
+test_load_high_ifindex()
+{
+    # Add a bunch of interfaces to run up the ifindex counter
+    for i in $(seq 64); do
+        ip link add dev veth-forw-test type veth
+        ip link del dev veth-forw-test
+    done
+
+    ip link add dev veth-forw-test type veth
+    check_run $XDP_FORWARD load veth-forw-test
+    check_run $XDP_FORWARD unload veth-forw-test
+}
+
 test_fwd_full()
 {
     # veth NAPI GRO support added this symbol; forwarding won't work without it
@@ -137,5 +150,6 @@ cleanup_tests()
         $XDP_LOADER unload $NS --all
         check_run ip netns exec ${NS_NAMES[-1]} nft flush ruleset
         check_run nft flush ruleset
+        ip link del dev veth-forw-test
     } >/dev/null 2>&1
 }