Subject: [PATCH v2 bpf-next 5/5] selftest: Add tests for XDP programs in devmap entries

From: David Ahern <[email-masked]>
Date: Wed, 27 May 2020 18:14:23 -0600

Add tests to verify ability to add an XDP program to a
entry in a DEVMAP.

Add negative tests to show DEVMAP programs can not be
attached to devices as a normal XDP program, and accesses
to egress_ifindex require BPF_XDP_DEVMAP attach type.

Signed-off-by: David Ahern <[email-masked]>
---
 .../bpf/prog_tests/xdp_devmap_attach.c        | 94 +++++++++++++++++++
 .../selftests/bpf/progs/test_xdp_devmap.c     | 19 ++++
 .../selftests/bpf/progs/test_xdp_devmap2.c    | 19 ++++
 .../bpf/progs/test_xdp_with_devmap.c          | 17 ++++
 4 files changed, 149 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/xdp_devmap_attach.c
 create mode 100644 tools/testing/selftests/bpf/progs/test_xdp_devmap.c
 create mode 100644 tools/testing/selftests/bpf/progs/test_xdp_devmap2.c
 create mode 100644 tools/testing/selftests/bpf/progs/test_xdp_with_devmap.c

diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_devmap_attach.c b/tools/testing/selftests/bpf/prog_tests/xdp_devmap_attach.c
new file mode 100644
index 000000000000..d81b2b366f39
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/xdp_devmap_attach.c
@@ -0,0 +1,94 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <uapi/linux/bpf.h>
+#include <linux/if_link.h>
+#include <test_progs.h>
+
+#define IFINDEX_LO 1
+
+void test_xdp_devmap_attach(void)
+{
+	struct bpf_prog_load_attr attr = {
+		.prog_type = BPF_PROG_TYPE_XDP,
+	};
+	struct bpf_object *obj, *dm_obj = NULL;
+	int err, dm_fd = -1, fd = -1, map_fd;
+	struct bpf_prog_info info = {};
+	struct devmap_val val = {
+		.ifindex = IFINDEX_LO,
+	};
+	__u32 id, len = sizeof(info);
+	__u32 duration = 0, idx = 0;
+
+	attr.file = "./test_xdp_with_devmap.o",
+	err = bpf_prog_load_xattr(&attr, &obj, &fd);
+	if (CHECK(err, "load of xdp program with 8-byte devmap",
+		  "err %d errno %d\n", err, errno))
+		return;
+
+	/* can not attach program with DEVMAPs that allow programs */
+	err = bpf_set_link_xdp_fd(IFINDEX_LO, fd, XDP_FLAGS_SKB_MODE);
+	CHECK(err == 0, "Generic attach of program with 8-byte devmap",
+	      "should have failed\n");
+
+	map_fd = bpf_object__find_map_fd_by_name(obj, "dm_ports");
+	if (CHECK(map_fd < 0, "Lookup dm_ports map",
+		  "err %d errno %d\n", err, errno))
+		goto out_close;
+
+	/*
+	 * basic test - load program to be installed in devmap;
+	 * also verifies access to ingress and egress ifindices.
+	 */
+	attr.expected_attach_type = BPF_XDP_DEVMAP;
+	attr.file = "./test_xdp_devmap.o";
+	err = bpf_prog_load_xattr(&attr, &dm_obj, &dm_fd);
+	if (CHECK(err, "Load of BPF_XDP_DEVMAP program",
+		  "err %d errno %d\n", err, errno))
+		goto out_close;
+
+	err = bpf_obj_get_info_by_fd(dm_fd, &info, &len);
+	if (CHECK_FAIL(err))
+		goto out_close;
+
+	val.bpf_prog_fd = dm_fd;
+	err = bpf_map_update_elem(map_fd, &idx, &val, 0);
+	CHECK(err, "Add program to devmap entry",
+	      "err %d errno %d\n", err, errno);
+
+	err = bpf_map_lookup_elem(map_fd, &id, &val);
+	CHECK(err, "Read devmap entry",
+	      "err %d errno %d\n", err, errno);
+	CHECK(info.id != val.bpf_prog_id, "Expected program id in devmap entry",
+	      "expected %u read %u\n", info.id, val.bpf_prog_id);
+
+	/* can not attach BPF_XDP_DEVMAP program to a device */
+	err = bpf_set_link_xdp_fd(IFINDEX_LO, dm_fd, XDP_FLAGS_SKB_MODE);
+	CHECK(err == 0, "Attach of BPF_XDP_DEVMAP program",
+	      "should have failed\n");
+
+	bpf_object__close(dm_obj);
+
+	/* Load of BPF_XDP_DEVMAP as XDP should fail because of egress index */
+	attr.expected_attach_type = 0;
+	err = bpf_prog_load_xattr(&attr, &dm_obj, &dm_fd);
+	if (CHECK(err == 0,
+		  "Load of XDP program accessing egress ifindex without attach type",
+		  "should have failed\n"))
+		bpf_object__close(dm_obj);
+
+	attr.file = "./xdp_dummy.o";
+	err = bpf_prog_load_xattr(&attr, &dm_obj, &dm_fd);
+	if (CHECK_FAIL(err))
+		goto out_close;
+
+	val.ifindex = 1;
+	val.bpf_prog_fd = dm_fd;
+	err = bpf_map_update_elem(map_fd, &idx, &val, 0);
+	CHECK(err == 0, "Add non-BPF_XDP_DEVMAP program to devmap entry",
+	      "should have failed\n");
+
+	bpf_object__close(dm_obj);
+
+out_close:
+	bpf_object__close(obj);
+}
diff --git a/tools/testing/selftests/bpf/progs/test_xdp_devmap.c b/tools/testing/selftests/bpf/progs/test_xdp_devmap.c
new file mode 100644
index 000000000000..64fc2c3cae01
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_xdp_devmap.c
@@ -0,0 +1,19 @@
+// SPDX-License-Identifier: GPL-2.0
+/* program inserted into devmap entry */
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+
+SEC("xdp_devmap_log")
+int xdpdm_devlog(struct xdp_md *ctx)
+{
+	char fmt[] = "devmap redirect: dev %u -> dev %u len %u\n";
+	void *data_end = (void *)(long)ctx->data_end;
+	void *data = (void *)(long)ctx->data;
+	unsigned int len = data_end - data;
+
+	bpf_trace_printk(fmt, sizeof(fmt), ctx->ingress_ifindex, ctx->egress_ifindex, len);
+
+	return XDP_PASS;
+}
+
+char _license[] SEC("license") = "GPL";
diff --git a/tools/testing/selftests/bpf/progs/test_xdp_devmap2.c b/tools/testing/selftests/bpf/progs/test_xdp_devmap2.c
new file mode 100644
index 000000000000..64fc2c3cae01
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_xdp_devmap2.c
@@ -0,0 +1,19 @@
+// SPDX-License-Identifier: GPL-2.0
+/* program inserted into devmap entry */
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+
+SEC("xdp_devmap_log")
+int xdpdm_devlog(struct xdp_md *ctx)
+{
+	char fmt[] = "devmap redirect: dev %u -> dev %u len %u\n";
+	void *data_end = (void *)(long)ctx->data_end;
+	void *data = (void *)(long)ctx->data;
+	unsigned int len = data_end - data;
+
+	bpf_trace_printk(fmt, sizeof(fmt), ctx->ingress_ifindex, ctx->egress_ifindex, len);
+
+	return XDP_PASS;
+}
+
+char _license[] SEC("license") = "GPL";
diff --git a/tools/testing/selftests/bpf/progs/test_xdp_with_devmap.c b/tools/testing/selftests/bpf/progs/test_xdp_with_devmap.c
new file mode 100644
index 000000000000..815cd59b4866
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_xdp_with_devmap.c
@@ -0,0 +1,17 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+
+struct bpf_map_def SEC("maps") dm_ports = {
+	.type = BPF_MAP_TYPE_DEVMAP,
+	.key_size = sizeof(__u32),
+	.value_size = sizeof(struct devmap_val),
+	.max_entries = 4,
+};
+
+SEC("xdp_devmap")
+int xdp_with_devmap(struct xdp_md *ctx)
+{
+	return bpf_redirect_map(&dm_ports, 1, 0);
+}
-- 
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