[PATCH bpf-next v2 2/6] selftests/bpf: add missing ns cleanups in btf_skc_cls_ingress

["Alexis Lothoré (eBPF Foundation)" <alexis.lothore@bootlin.com>]

btf_skc_cls_ingress.c currently runs two subtests, and create a
dedicated network namespace for each, but never cleans up the created
namespace once the test has ended.

Add missing namespace cleanup after each subtest to avoid accumulating
namespaces for each new subtest. While at it, switch namespace
management to netns_{new,free}

Signed-off-by: Alexis Lothoré (eBPF Foundation) <alexis.lothore@bootlin.com>
---
Changes in v2:
- slightly reword commit message to fix mistake
- remove `ip link set lo up` in dedicated ns, handled by netns_new
---
 .../selftests/bpf/prog_tests/btf_skc_cls_ingress.c | 33 +++++++++++++---------
 1 file changed, 19 insertions(+), 14 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/btf_skc_cls_ingress.c b/tools/testing/selftests/bpf/prog_tests/btf_skc_cls_ingress.c
index 5d8d7736edc095b647ca3fbc12cac0440b60140e..c88fb0e3048c81a09cf4b0b9df434cf8d4c6ff33 100644
--- a/tools/testing/selftests/bpf/prog_tests/btf_skc_cls_ingress.c
+++ b/tools/testing/selftests/bpf/prog_tests/btf_skc_cls_ingress.c
@@ -17,32 +17,30 @@
 #include "test_progs.h"
 #include "test_btf_skc_cls_ingress.skel.h"
 
+#define TEST_NS "skc_cls_ingress"
+
 static struct test_btf_skc_cls_ingress *skel;
 static struct sockaddr_in6 srv_sa6;
 static __u32 duration;
 
-static int prepare_netns(void)
+static struct netns_obj *prepare_netns(void)
 {
 	LIBBPF_OPTS(bpf_tc_hook, qdisc_lo, .attach_point = BPF_TC_INGRESS);
 	LIBBPF_OPTS(bpf_tc_opts, tc_attach,
 		    .prog_fd = bpf_program__fd(skel->progs.cls_ingress));
+	struct netns_obj *ns = NULL;
 
-	if (CHECK(unshare(CLONE_NEWNET), "create netns",
-		  "unshare(CLONE_NEWNET): %s (%d)",
-		  strerror(errno), errno))
-		return -1;
-
-	if (CHECK(system("ip link set dev lo up"),
-		  "ip link set dev lo up", "failed\n"))
-		return -1;
+	ns = netns_new(TEST_NS, true);
+	if (!ASSERT_OK_PTR(ns, "create and join netns"))
+		return ns;
 
 	qdisc_lo.ifindex = if_nametoindex("lo");
 	if (!ASSERT_OK(bpf_tc_hook_create(&qdisc_lo), "qdisc add dev lo clsact"))
-		return -1;
+		goto free_ns;
 
 	if (!ASSERT_OK(bpf_tc_attach(&qdisc_lo, &tc_attach),
 		       "filter add dev lo ingress"))
-		return -1;
+		goto free_ns;
 
 	/* Ensure 20 bytes options (i.e. in total 40 bytes tcp header) for the
 	 * bpf_tcp_gen_syncookie() helper.
@@ -50,9 +48,13 @@ static int prepare_netns(void)
 	if (write_sysctl("/proc/sys/net/ipv4/tcp_window_scaling", "1") ||
 	    write_sysctl("/proc/sys/net/ipv4/tcp_timestamps", "1") ||
 	    write_sysctl("/proc/sys/net/ipv4/tcp_sack", "1"))
-		return -1;
+		goto free_ns;
+
+	return ns;
 
-	return 0;
+free_ns:
+	netns_free(ns);
+	return NULL;
 }
 
 static void reset_test(void)
@@ -169,6 +171,7 @@ void test_btf_skc_cls_ingress(void)
 	int i;
 
 	skel = test_btf_skc_cls_ingress__open_and_load();
+	struct netns_obj *ns;
 	if (CHECK(!skel, "test_btf_skc_cls_ingress__open_and_load", "failed\n"))
 		return;
 
@@ -176,13 +179,15 @@ void test_btf_skc_cls_ingress(void)
 		if (!test__start_subtest(tests[i].desc))
 			continue;
 
-		if (prepare_netns())
+		ns = prepare_netns();
+		if (!ns)
 			break;
 
 		tests[i].run();
 
 		print_err_line();
 		reset_test();
+		netns_free(ns);
 	}
 
 	test_btf_skc_cls_ingress__destroy(skel);

-- 
2.47.0