selftest: Add tests for XDP programs in CPUMAP entries

Similar to what have been done for DEVMAP, introduce tests to verify
ability to add a XDP program to an entry in a CPUMAP.
Verify CPUMAP programs can not be attached to devices as a normal
XDP program, and only programs with BPF_XDP_CPUMAP attach type can
be loaded in a CPUMAP.

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/9c632fcea5382ea7b4578bd06b6eddf382c3550b.1594734381.git.lorenzo@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
new file mode 100644 (file)
index 0000000..0176573
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/xdp_cpumap_attach.c
@@ -0,0 +1,70 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <uapi/linux/bpf.h>
+#include <linux/if_link.h>
+#include <test_progs.h>
+
+#include "test_xdp_with_cpumap_helpers.skel.h"
+
+#define IFINDEX_LO     1
+
+void test_xdp_with_cpumap_helpers(void)
+{
+       struct test_xdp_with_cpumap_helpers *skel;
+       struct bpf_prog_info info = {};
+       struct bpf_cpumap_val val = {
+               .qsize = 192,
+       };
+       __u32 duration = 0, idx = 0;
+       __u32 len = sizeof(info);
+       int err, prog_fd, map_fd;
+
+       skel = test_xdp_with_cpumap_helpers__open_and_load();
+       if (CHECK_FAIL(!skel)) {
+               perror("test_xdp_with_cpumap_helpers__open_and_load");
+               return;
+       }
+
+       /* can not attach program with cpumaps that allow programs
+        * as xdp generic
+        */
+       prog_fd = bpf_program__fd(skel->progs.xdp_redir_prog);
+       err = bpf_set_link_xdp_fd(IFINDEX_LO, prog_fd, XDP_FLAGS_SKB_MODE);
+       CHECK(err == 0, "Generic attach of program with 8-byte CPUMAP",
+             "should have failed\n");
+
+       prog_fd = bpf_program__fd(skel->progs.xdp_dummy_cm);
+       map_fd = bpf_map__fd(skel->maps.cpu_map);
+       err = bpf_obj_get_info_by_fd(prog_fd, &info, &len);
+       if (CHECK_FAIL(err))
+               goto out_close;
+
+       val.bpf_prog.fd = prog_fd;
+       err = bpf_map_update_elem(map_fd, &idx, &val, 0);
+       CHECK(err, "Add program to cpumap entry", "err %d errno %d\n",
+             err, errno);
+
+       err = bpf_map_lookup_elem(map_fd, &idx, &val);
+       CHECK(err, "Read cpumap entry", "err %d errno %d\n", err, errno);
+       CHECK(info.id != val.bpf_prog.id, "Expected program id in cpumap entry",
+             "expected %u read %u\n", info.id, val.bpf_prog.id);
+
+       /* can not attach BPF_XDP_CPUMAP program to a device */
+       err = bpf_set_link_xdp_fd(IFINDEX_LO, prog_fd, XDP_FLAGS_SKB_MODE);
+       CHECK(err == 0, "Attach of BPF_XDP_CPUMAP program",
+             "should have failed\n");
+
+       val.qsize = 192;
+       val.bpf_prog.fd = bpf_program__fd(skel->progs.xdp_dummy_prog);
+       err = bpf_map_update_elem(map_fd, &idx, &val, 0);
+       CHECK(err == 0, "Add non-BPF_XDP_CPUMAP program to cpumap entry",
+             "should have failed\n");
+
+out_close:
+       test_xdp_with_cpumap_helpers__destroy(skel);
+}
+
+void test_xdp_cpumap_attach(void)
+{
+       if (test__start_subtest("cpumap_with_progs"))
+               test_xdp_with_cpumap_helpers();
+}

diff --git a/tools/testing/selftests/bpf/progs/test_xdp_with_cpumap_helpers.c b/tools/testing/selftests/bpf/progs/test_xdp_with_cpumap_helpers.c
new file mode 100644 (file)
index 0000000..59ee4f1
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_xdp_with_cpumap_helpers.c
@@ -0,0 +1,36 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+
+#define IFINDEX_LO     1
+
+struct {
+       __uint(type, BPF_MAP_TYPE_CPUMAP);
+       __uint(key_size, sizeof(__u32));
+       __uint(value_size, sizeof(struct bpf_cpumap_val));
+       __uint(max_entries, 4);
+} cpu_map SEC(".maps");
+
+SEC("xdp_redir")
+int xdp_redir_prog(struct xdp_md *ctx)
+{
+       return bpf_redirect_map(&cpu_map, 1, 0);
+}
+
+SEC("xdp_dummy")
+int xdp_dummy_prog(struct xdp_md *ctx)
+{
+       return XDP_PASS;
+}
+
+SEC("xdp_cpumap/dummy_cm")
+int xdp_dummy_cm(struct xdp_md *ctx)
+{
+       if (ctx->ingress_ifindex == IFINDEX_LO)
+               return XDP_DROP;
+
+       return XDP_PASS;
+}
+
+char _license[] SEC("license") = "GPL";