[PATCH bpf-next v6 3/6] selftests/bpf: netns_new() and netns_free() helpers.

Kui-Feng Lee
2024-08-07T18:31:57Z

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.

Signed-off-by: Kui-Feng Lee <thinker.li@gmail.com>
---
tools/testing/selftests/bpf/network_helpers.c | 40 +++++++++
tools/testing/selftests/bpf/network_helpers.h | 2 +
tools/testing/selftests/bpf/test_progs.c | 90 +++++++++++++++++++
tools/testing/selftests/bpf/test_progs.h | 4 +
4 files changed, 136 insertions(+)

diff --git a/tools/testing/selftests/bpf/network_helpers.c b/tools/testing/selftests/bpf/network_helpers.c
index 462aeadd767e..3611c542241c 100644
--- a/tools/testing/selftests/bpf/network_helpers.c
+++ b/tools/testing/selftests/bpf/network_helpers.c
@@ -445,6 +445,46 @@ char *ping_command(int family)
return "ping";
}

+int make_netns(const char *name)
+{
+ char *cmd;
+ int r;
+
+ r = asprintf(&cmd, "ip netns add %s", name);
+ if (r < 0) {
+ log_err("Failed to malloc cmd");
+ return -1;
+ }
+
+ r = system(cmd);
+ if (r > 0)
+ /* exit code */
+ r = -r;
+
+ free(cmd);
+ return r;
+}
+
+int remove_netns(const char *name)
+{
+ char *cmd;
+ int r;
+
+ r = asprintf(&cmd, "ip netns del %s >/dev/null 2>&1", name);
+ if (r < 0) {
+ log_err("Failed to malloc cmd");
+ return -1;
+ }
+
+ r = system(cmd);
+ if (r > 0)
+ /* exit code */
+ r = -r;
+
+ free(cmd);
+ return r;
+}
+
struct nstoken {
int orig_netns_fd;
};
diff --git a/tools/testing/selftests/bpf/network_helpers.h b/tools/testing/selftests/bpf/network_helpers.h
index 0d032ae706c6..c72c16e1aff8 100644
--- a/tools/testing/selftests/bpf/network_helpers.h
+++ b/tools/testing/selftests/bpf/network_helpers.h
@@ -93,6 +93,8 @@ struct nstoken;
struct nstoken *open_netns(const char *name);
void close_netns(struct nstoken *token);
int send_recv_data(int lfd, int fd, uint32_t total_bytes);
+int make_netns(const char *name);
+int remove_netns(const char *name);

static __u16 csum_fold(__u32 csum)
{
diff --git a/tools/testing/selftests/bpf/test_progs.c b/tools/testing/selftests/bpf/test_progs.c
index fed22e9fd223..3f79ce52aeb0 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 +644,94 @@ int compare_stack_ips(int smap_fd, int amap_fd, int stack_trace_len)
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;
+
+ /* Set the network namespace of the current process */
+ if (open) {
+ netns_obj->nstoken = open_netns(nsname);
+ if (!netns_obj->nstoken)
+ 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);
+ } else {
+ netns_obj->tmon = NULL;
+ }
+
+ system("ip link set lo up");
+
+ return netns_obj;
+fail:
+ close_netns(netns_obj->nstoken);
+ 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;
+ if (netns_obj->tmon)
+ 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; \
diff --git a/tools/testing/selftests/bpf/test_progs.h b/tools/testing/selftests/bpf/test_progs.h
index 966011eb7ec8..3ad131de14c6 100644
--- a/tools/testing/selftests/bpf/test_progs.h
+++ b/tools/testing/selftests/bpf/test_progs.h
@@ -430,6 +430,10 @@ int write_sysctl(const char *sysctl, const char *value);
int get_bpf_max_tramp_links_from(struct btf *btf);
int get_bpf_max_tramp_links(void);

+struct netns_obj;
+struct netns_obj *netns_new(const char *name, bool open);
+void netns_free(struct netns_obj *netns);
+
#ifdef __x86_64__
#define SYS_NANOSLEEP_KPROBE_NAME "__x64_sys_nanosleep"
#elif defined(__s390x__)
--
2.34.1