selftests/bpf: Add a bpf fq qdisc to selftest

This test implements a more sophisticated qdisc using bpf. The bpf fair-
queueing (fq) qdisc gives each flow an equal chance to transmit data. It
also respects the timestamp of skb for rate limiting.

Signed-off-by: Amery Hung <[email protected]>
Signed-off-by: Martin KaFai Lau <[email protected]>
Acked-by: Toke Høiland-Jørgensen <[email protected]>
Link: https://patch.msgid.link/[email protected]

Author: Amery Hung

tools/testing/selftests/bpf/prog_tests/bpf_qdisc.c

@@ -6,6 +6,7 @@
 
 #include "network_helpers.h"
 #include "bpf_qdisc_fifo.skel.h"
+#include "bpf_qdisc_fq.skel.h"
 
 #define LO_IFINDEX 1
 
@@ -66,6 +67,27 @@ static void test_fifo(void)
 	bpf_qdisc_fifo__destroy(fifo_skel);
 }
 
+static void test_fq(void)
+{
+	struct bpf_qdisc_fq *fq_skel;
+	struct bpf_link *link;
+
+	fq_skel = bpf_qdisc_fq__open_and_load();
+	if (!ASSERT_OK_PTR(fq_skel, "bpf_qdisc_fq__open_and_load"))
+		return;
+
+	link = bpf_map__attach_struct_ops(fq_skel->maps.fq);
+	if (!ASSERT_OK_PTR(link, "bpf_map__attach_struct_ops")) {
+		bpf_qdisc_fq__destroy(fq_skel);
+		return;
+	}
+
+	do_test("bpf_fq");
+
+	bpf_link__destroy(link);
+	bpf_qdisc_fq__destroy(fq_skel);
+}
+
 void test_bpf_qdisc(void)
 {
 	struct netns_obj *netns;
@@ -76,6 +98,8 @@ void test_bpf_qdisc(void)
 
 	if (test__start_subtest("fifo"))
 		test_fifo();
+	if (test__start_subtest("fq"))
+		test_fq();
 
 	netns_free(netns);
 }