selftests/bpf: test_xdp_veth: Use a dedicated namespace

Tests use the root network namespace, so they aren't fully independent
of each other. For instance, the index of the created veth interfaces
is incremented every time a new test is launched.

Wrap the network topology in a network namespace to ensure full
isolation. Use the append_tid() helper to ensure the uniqueness of this
namespace's name during parallel runs.
Remove the use of the append_tid() on the veth names as they now belong
to an already unique namespace.
Simplify cleanup_network() by directly deleting the namespaces

Signed-off-by: Bastien Curutchet (eBPF Foundation) <bastien.curutchet@bootlin.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://patch.msgid.link/20250212-redirect-multi-v5-2-fd0d39fca6e6@bootlin.com

diff --git a/tools/testing/selftests/bpf/prog_tests/test_xdp_veth.c b/tools/testing/selftests/bpf/prog_tests/test_xdp_veth.c
index 4fa2b452de7c8361ec575d63a3ce6fbedc220773..a1c79af23bec25529af5b549d16b2cbfaf1cebd4 100644 (file)
--- a/tools/testing/selftests/bpf/prog_tests/test_xdp_veth.c
+++ b/tools/testing/selftests/bpf/prog_tests/test_xdp_veth.c
@@ -9,7 +9,11 @@
  *  | veth11 |        | veth22 |       | veth33 |
  *  ----|-----        -----|----       -----|----
  *      |                  |                |
- *    veth1              veth2            veth3
+ *  ----|------------------|----------------|----
+ *  | veth1              veth2            veth3 |
+ *  |                                           |
+ *  |                     NSO                   |
+ *  ---------------------------------------------
  *
  * Test cases:
  *  - [test_xdp_veth_redirect] : ping veth33 from veth11
@@ -52,10 +56,12 @@ struct veth_configuration {
 };
 
 struct net_configuration {
+       char ns0_name[NS_NAME_MAX_LEN];
        struct veth_configuration veth_cfg[VETH_PAIRS_COUNT];
 };
 
 static const struct net_configuration default_config = {
+       .ns0_name = "ns0-",
        {
                {
                        .local_veth = "veth1-",
@@ -144,21 +150,30 @@ static int attach_programs_to_veth_pair(struct bpf_object **objs, size_t nb_obj,
 
 static int create_network(struct net_configuration *net_config)
 {
+       struct nstoken *nstoken = NULL;
        int i, err;
 
        memcpy(net_config, &default_config, sizeof(struct net_configuration));
 
-       /* First create and configure all interfaces */
+       /* Create unique namespaces */
+       err = append_tid(net_config->ns0_name, NS_NAME_MAX_LEN);
+       if (!ASSERT_OK(err, "append TID to ns0 name"))
+               goto fail;
+       SYS(fail, "ip netns add %s", net_config->ns0_name);
+
        for (i = 0; i < VETH_PAIRS_COUNT; i++) {
                err = append_tid(net_config->veth_cfg[i].namespace, NS_NAME_MAX_LEN);
                if (!ASSERT_OK(err, "append TID to ns name"))
-                       return -1;
+                       goto fail;
+               SYS(fail, "ip netns add %s", net_config->veth_cfg[i].namespace);
+       }
 
-               err = append_tid(net_config->veth_cfg[i].local_veth, VETH_NAME_MAX_LEN);
-               if (!ASSERT_OK(err, "append TID to local veth name"))
-                       return -1;
+       /* Create interfaces */
+       nstoken = open_netns(net_config->ns0_name);
+       if (!nstoken)
+               goto fail;
 
-               SYS(fail, "ip netns add %s", net_config->veth_cfg[i].namespace);
+       for (i = 0; i < VETH_PAIRS_COUNT; i++) {
                SYS(fail, "ip link add %s type veth peer name %s netns %s",
                    net_config->veth_cfg[i].local_veth, net_config->veth_cfg[i].remote_veth,
                    net_config->veth_cfg[i].namespace);
@@ -172,29 +187,21 @@ static int create_network(struct net_configuration *net_config)
                    net_config->veth_cfg[i].remote_veth);
        }
 
+       close_netns(nstoken);
        return 0;
 
 fail:
+       close_netns(nstoken);
        return -1;
 }
 
 static void cleanup_network(struct net_configuration *net_config)
 {
-       struct nstoken *nstoken;
        int i;
 
-       for (i = 0; i < VETH_PAIRS_COUNT; i++) {
-               bpf_xdp_detach(if_nametoindex(net_config->veth_cfg[i].local_veth), 0, NULL);
-               nstoken = open_netns(net_config->veth_cfg[i].namespace);
-               if (nstoken) {
-                       bpf_xdp_detach(if_nametoindex(net_config->veth_cfg[i].remote_veth),
-                                      0, NULL);
-                       close_netns(nstoken);
-               }
-               /* in case the detach failed */
-               SYS_NOFAIL("ip link del %s", net_config->veth_cfg[i].local_veth);
+       SYS_NOFAIL("ip netns del %s", net_config->ns0_name);
+       for (i = 0; i < VETH_PAIRS_COUNT; i++)
                SYS_NOFAIL("ip netns del %s", net_config->veth_cfg[i].namespace);
-       }
 }
 
 #define VETH_REDIRECT_SKEL_NB  3
@@ -223,6 +230,7 @@ static void xdp_veth_redirect(u32 flags)
        struct bpf_object *bpf_objs[VETH_REDIRECT_SKEL_NB];
        struct xdp_redirect_map *xdp_redirect_map;
        struct net_configuration net_config;
+       struct nstoken *nstoken = NULL;
        struct xdp_dummy *xdp_dummy;
        struct xdp_tx *xdp_tx;
        int map_fd;
@@ -251,6 +259,11 @@ static void xdp_veth_redirect(u32 flags)
        bpf_objs[0] = xdp_dummy->obj;
        bpf_objs[1] = xdp_tx->obj;
        bpf_objs[2] = xdp_redirect_map->obj;
+
+       nstoken = open_netns(net_config.ns0_name);
+       if (!ASSERT_OK_PTR(nstoken, "open NS0"))
+               goto destroy_xdp_redirect_map;
+
        for (i = 0; i < VETH_PAIRS_COUNT; i++) {
                int next_veth = net_config.veth_cfg[i].next_veth;
                int interface_id;
@@ -274,6 +287,7 @@ static void xdp_veth_redirect(u32 flags)
                             net_config.veth_cfg[0].namespace, IP_DST), "ping");
 
 destroy_xdp_redirect_map:
+       close_netns(nstoken);
        xdp_redirect_map__destroy(xdp_redirect_map);
 destroy_xdp_tx:
        xdp_tx__destroy(xdp_tx);