[PATCH bpf-next v3 18/18] selftests/bpf: Test attaching bpf qdisc to mq and non root

[Amery Hung <ameryhung@gmail.com>]

Until we are certain that existing classful qdiscs work with bpf qdisc,
make sure we don't allow attaching a bpf qdisc to non root. Meanwhile,
attaching to mq is allowed.

Signed-off-by: Amery Hung <ameryhung@gmail.com>
---
 tools/testing/selftests/bpf/config            |   1 +
 .../selftests/bpf/prog_tests/bpf_qdisc.c      | 111 +++++++++++++++++-
 2 files changed, 110 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/bpf/config b/tools/testing/selftests/bpf/config
index 6b0cab55bd2d..3201a962b3dc 100644
--- a/tools/testing/selftests/bpf/config
+++ b/tools/testing/selftests/bpf/config
@@ -74,6 +74,7 @@ CONFIG_NET_MPLS_GSO=y
 CONFIG_NET_SCH_BPF=y
 CONFIG_NET_SCH_FQ=y
 CONFIG_NET_SCH_INGRESS=y
+CONFIG_NET_SCH_HTB=y
 CONFIG_NET_SCHED=y
 CONFIG_NETDEVSIM=y
 CONFIG_NETFILTER=y
diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_qdisc.c b/tools/testing/selftests/bpf/prog_tests/bpf_qdisc.c
index 7e8e3170e6b6..f3158170edff 100644
--- a/tools/testing/selftests/bpf/prog_tests/bpf_qdisc.c
+++ b/tools/testing/selftests/bpf/prog_tests/bpf_qdisc.c
@@ -86,18 +86,125 @@ static void test_fq(void)
 	bpf_qdisc_fq__destroy(fq_skel);
 }
 
+static int netdevsim_write_cmd(const char *path, const char *cmd)
+{
+	FILE *fp;
+
+	fp = fopen(path, "w");
+	if (!ASSERT_OK_PTR(fp, "write_netdevsim_cmd"))
+		return -errno;
+
+	fprintf(fp, cmd);
+	fclose(fp);
+	return 0;
+}
+
+static void test_qdisc_attach_to_mq(void)
+{
+	DECLARE_LIBBPF_OPTS(bpf_tc_hook, hook,
+			    .attach_point = BPF_TC_QDISC,
+			    .parent = 0x00010001,
+			    .handle = 0x8000000,
+			    .qdisc = "bpf_fifo");
+	struct bpf_qdisc_fifo *fifo_skel;
+	struct bpf_link *link;
+	int err;
+
+	hook.ifindex = if_nametoindex("eni1np1");
+	if (!ASSERT_NEQ(hook.ifindex, 0, "if_nametoindex"))
+		return;
+
+	fifo_skel = bpf_qdisc_fifo__open_and_load();
+	if (!ASSERT_OK_PTR(fifo_skel, "bpf_qdisc_fifo__open_and_load"))
+		return;
+
+	link = bpf_map__attach_struct_ops(fifo_skel->maps.fifo);
+	if (!ASSERT_OK_PTR(link, "bpf_map__attach_struct_ops")) {
+		bpf_qdisc_fifo__destroy(fifo_skel);
+		return;
+	}
+
+	ASSERT_OK(system("tc qdisc add dev eni1np1 root handle 1: mq"), "create mq");
+
+	err = bpf_tc_hook_create(&hook);
+	ASSERT_OK(err, "attach qdisc");
+
+	bpf_tc_hook_destroy(&hook);
+
+	ASSERT_OK(system("tc qdisc delete dev eni1np1 root mq"), "delete mq");
+
+	bpf_link__destroy(link);
+	bpf_qdisc_fifo__destroy(fifo_skel);
+}
+
+static void test_qdisc_attach_to_non_root(void)
+{
+	DECLARE_LIBBPF_OPTS(bpf_tc_hook, hook, .ifindex = LO_IFINDEX,
+			    .attach_point = BPF_TC_QDISC,
+			    .parent = 0x00010001,
+			    .handle = 0x8000000,
+			    .qdisc = "bpf_fifo");
+	struct bpf_qdisc_fifo *fifo_skel;
+	struct bpf_link *link;
+	int err;
+
+	fifo_skel = bpf_qdisc_fifo__open_and_load();
+	if (!ASSERT_OK_PTR(fifo_skel, "bpf_qdisc_fifo__open_and_load"))
+		return;
+
+	link = bpf_map__attach_struct_ops(fifo_skel->maps.fifo);
+	if (!ASSERT_OK_PTR(link, "bpf_map__attach_struct_ops")) {
+		bpf_qdisc_fifo__destroy(fifo_skel);
+		return;
+	}
+
+	ASSERT_OK(system("tc qdisc add dev lo root handle 1: htb"), "create htb");
+	ASSERT_OK(system("tc class add dev lo parent 1: classid 1:1 htb rate 75Kbit"), "create htb class");
+
+	err = bpf_tc_hook_create(&hook);
+	ASSERT_ERR(err, "attach qdisc");
+
+	bpf_tc_hook_destroy(&hook);
+
+	ASSERT_OK(system("tc qdisc delete dev lo root htb"), "delete htb");
+
+	bpf_link__destroy(link);
+	bpf_qdisc_fifo__destroy(fifo_skel);
+}
+
 void test_bpf_qdisc(void)
 {
+	struct nstoken *nstoken = NULL;
 	struct netns_obj *netns;
+	int err;
 
-	netns = netns_new("bpf_qdisc_ns", true);
+	netns = netns_new("bpf_qdisc_ns", false);
 	if (!ASSERT_OK_PTR(netns, "netns_new"))
 		return;
 
+	err = netdevsim_write_cmd("/sys/bus/netdevsim/new_device", "1 1 4");
+	if (!ASSERT_OK(err, "create netdevsim")) {
+		netns_free(netns);
+		return;
+	}
+
+	ASSERT_OK(system("ip link set eni1np1 netns bpf_qdisc_ns"), "ip link set netdevsim");
+
+	nstoken = open_netns("bpf_qdisc_ns");
+	if (!ASSERT_OK_PTR(nstoken, "open_netns"))
+		goto out;
+
 	if (test__start_subtest("fifo"))
 		test_fifo();
 	if (test__start_subtest("fq"))
 		test_fq();
-
+	if (test__start_subtest("attach to mq"))
+		test_qdisc_attach_to_mq();
+	if (test__start_subtest("attach to non root"))
+		test_qdisc_attach_to_non_root();
+
+out:
+	err = netdevsim_write_cmd("/sys/bus/netdevsim/del_device", "1");
+	ASSERT_OK(err, "delete netdevsim");
 	netns_free(netns);
 }
-- 
2.47.1