selftests/bpf: make xdp_cpumap_attach keep redirect prog attached

Current test only checks attach/detach on cpu map type program, and so
does not check that it can be properly executed, neither that it
redirects correctly.

Update the existing test to extend its coverage:
- keep the redirected program loaded
- try to execute it through bpf_prog_test_run_opts with some dummy
  context

While at it, bring the following minor improvements:
- isolate test interface in its own namespace

Signed-off-by: Alexis Lothoré (eBPF Foundation) <alexis.lothore@bootlin.com>
Link: https://lore.kernel.org/r/20241009-convert_xdp_tests-v3-2-51cea913710c@bootlin.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>

diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_cpumap_attach.c b/tools/testing/selftests/bpf/prog_tests/xdp_cpumap_attach.c
index 481626a875d1c3db9c7bfe92c3cca6e967a6d45c..88e8a886d1e611d2fc5e8891e8304ad8aa7e5a38 100644 (file)
--- a/tools/testing/selftests/bpf/prog_tests/xdp_cpumap_attach.c
+++ b/tools/testing/selftests/bpf/prog_tests/xdp_cpumap_attach.c
@@ -2,35 +2,41 @@
 #include <uapi/linux/bpf.h>
 #include <linux/if_link.h>
 #include <test_progs.h>
+#include <network_helpers.h>
 
 #include "test_xdp_with_cpumap_frags_helpers.skel.h"
 #include "test_xdp_with_cpumap_helpers.skel.h"
 
 #define IFINDEX_LO     1
+#define TEST_NS "cpu_attach_ns"
 
 static void test_xdp_with_cpumap_helpers(void)
 {
-       struct test_xdp_with_cpumap_helpers *skel;
+       struct test_xdp_with_cpumap_helpers *skel = NULL;
        struct bpf_prog_info info = {};
        __u32 len = sizeof(info);
        struct bpf_cpumap_val val = {
                .qsize = 192,
        };
-       int err, prog_fd, map_fd;
+       int err, prog_fd, prog_redir_fd, map_fd;
+       struct nstoken *nstoken = NULL;
        __u32 idx = 0;
 
+       SYS(out_close, "ip netns add %s", TEST_NS);
+       nstoken = open_netns(TEST_NS);
+       if (!ASSERT_OK_PTR(nstoken, "open_netns"))
+               goto out_close;
+       SYS(out_close, "ip link set dev lo up");
+
        skel = test_xdp_with_cpumap_helpers__open_and_load();
        if (!ASSERT_OK_PTR(skel, "test_xdp_with_cpumap_helpers__open_and_load"))
                return;
 
-       prog_fd = bpf_program__fd(skel->progs.xdp_redir_prog);
-       err = bpf_xdp_attach(IFINDEX_LO, prog_fd, XDP_FLAGS_SKB_MODE, NULL);
+       prog_redir_fd = bpf_program__fd(skel->progs.xdp_redir_prog);
+       err = bpf_xdp_attach(IFINDEX_LO, prog_redir_fd, XDP_FLAGS_SKB_MODE, NULL);
        if (!ASSERT_OK(err, "Generic attach of program with 8-byte CPUMAP"))
                goto out_close;
 
-       err = bpf_xdp_detach(IFINDEX_LO, XDP_FLAGS_SKB_MODE, NULL);
-       ASSERT_OK(err, "XDP program detach");
-
        prog_fd = bpf_program__fd(skel->progs.xdp_dummy_cm);
        map_fd = bpf_map__fd(skel->maps.cpu_map);
        err = bpf_prog_get_info_by_fd(prog_fd, &info, &len);
@@ -45,6 +51,23 @@ static void test_xdp_with_cpumap_helpers(void)
        ASSERT_OK(err, "Read cpumap entry");
        ASSERT_EQ(info.id, val.bpf_prog.id, "Match program id to cpumap entry prog_id");
 
+       /* send a packet to trigger any potential bugs in there */
+       char data[10] = {};
+       DECLARE_LIBBPF_OPTS(bpf_test_run_opts, opts,
+                           .data_in = &data,
+                           .data_size_in = 10,
+                           .flags = BPF_F_TEST_XDP_LIVE_FRAMES,
+                           .repeat = 1,
+               );
+       err = bpf_prog_test_run_opts(prog_redir_fd, &opts);
+       ASSERT_OK(err, "XDP test run");
+
+       /* wait for the packets to be flushed */
+       kern_sync_rcu();
+
+       err = bpf_xdp_detach(IFINDEX_LO, XDP_FLAGS_SKB_MODE, NULL);
+       ASSERT_OK(err, "XDP program detach");
+
        /* can not attach BPF_XDP_CPUMAP program to a device */
        err = bpf_xdp_attach(IFINDEX_LO, prog_fd, XDP_FLAGS_SKB_MODE, NULL);
        if (!ASSERT_NEQ(err, 0, "Attach of BPF_XDP_CPUMAP program"))
@@ -65,6 +88,8 @@ static void test_xdp_with_cpumap_helpers(void)
        ASSERT_NEQ(err, 0, "Add BPF_XDP program with frags to cpumap entry");
 
 out_close:
+       close_netns(nstoken);
+       SYS_NOFAIL("ip netns del %s", TEST_NS);
        test_xdp_with_cpumap_helpers__destroy(skel);
 }
 
@@ -111,7 +136,7 @@ out_close:
        test_xdp_with_cpumap_frags_helpers__destroy(skel);
 }
 
-void serial_test_xdp_cpumap_attach(void)
+void test_xdp_cpumap_attach(void)
 {
        if (test__start_subtest("CPUMAP with programs in entries"))
                test_xdp_with_cpumap_helpers();