selftests/bpf: netns_new() and netns_free() helpers.

netns_new()/netns_free() create/delete network namespaces. They support the
option '-m' of test_progs to start/stop traffic monitor for the network
namespace being created for matched tests.

Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Signed-off-by: Kui-Feng Lee <thinker.li@gmail.com>
Link: https://lore.kernel.org/r/20240815053254.470944-4-thinker.li@gmail.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>

1 files changed, 88 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/test_progs.c b/tools/testing/selftests/bpf/test_progs.c
index f8ed1a16a884..f45b06791444 100644
--- a/tools/testing/selftests/bpf/test_progs.c
+++ b/tools/testing/selftests/bpf/test_progs.c
@@ -18,6 +18,8 @@
 #include <bpf/btf.h>
 #include "json_writer.h"
 
+#include "network_helpers.h"
+
 #ifdef __GLIBC__
 #include <execinfo.h> /* backtrace */
 #endif
@@ -642,6 +644,92 @@ out:
 	return err;
 }
 
+struct netns_obj {
+	char *nsname;
+	struct tmonitor_ctx *tmon;
+	struct nstoken *nstoken;
+};
+
+/* Create a new network namespace with the given name.
+ *
+ * Create a new network namespace and set the network namespace of the
+ * current process to the new network namespace if the argument "open" is
+ * true. This function should be paired with netns_free() to release the
+ * resource and delete the network namespace.
+ *
+ * It also implements the functionality of the option "-m" by starting
+ * traffic monitor on the background to capture the packets in this network
+ * namespace if the current test or subtest matching the pattern.
+ *
+ * nsname: the name of the network namespace to create.
+ * open: open the network namespace if true.
+ *
+ * Return: the network namespace object on success, NULL on failure.
+ */
+struct netns_obj *netns_new(const char *nsname, bool open)
+{
+	struct netns_obj *netns_obj = malloc(sizeof(*netns_obj));
+	const char *test_name, *subtest_name;
+	int r;
+
+	if (!netns_obj)
+		return NULL;
+	memset(netns_obj, 0, sizeof(*netns_obj));
+
+	netns_obj->nsname = strdup(nsname);
+	if (!netns_obj->nsname)
+		goto fail;
+
+	/* Create the network namespace */
+	r = make_netns(nsname);
+	if (r)
+		goto fail;
+
+	/* Start traffic monitor */
+	if (env.test->should_tmon ||
+	    (env.subtest_state && env.subtest_state->should_tmon)) {
+		test_name = env.test->test_name;
+		subtest_name = env.subtest_state ? env.subtest_state->name : NULL;
+		netns_obj->tmon = traffic_monitor_start(nsname, test_name, subtest_name);
+		if (!netns_obj->tmon) {
+			fprintf(stderr, "Failed to start traffic monitor for %s\n", nsname);
+			goto fail;
+		}
+	} else {
+		netns_obj->tmon = NULL;
+	}
+
+	if (open) {
+		netns_obj->nstoken = open_netns(nsname);
+		if (!netns_obj->nstoken)
+			goto fail;
+	}
+
+	return netns_obj;
+fail:
+	traffic_monitor_stop(netns_obj->tmon);
+	remove_netns(nsname);
+	free(netns_obj->nsname);
+	free(netns_obj);
+	return NULL;
+}
+
+/* Delete the network namespace.
+ *
+ * This function should be paired with netns_new() to delete the namespace
+ * created by netns_new().
+ */
+void netns_free(struct netns_obj *netns_obj)
+{
+	if (!netns_obj)
+		return;
+	traffic_monitor_stop(netns_obj->tmon);
+	close_netns(netns_obj->nstoken);
+	remove_netns(netns_obj->nsname);
+	free(netns_obj->nsname);
+	free(netns_obj);
+}
+
 /* extern declarations for test funcs */
 #define DEFINE_TEST(name)				\
 	extern void test_##name(void) __weak;		\