On 6/4/21 3:02 PM, Zvi Effron wrote:
Add a test for using xdp_md as a context to BPF_PROG_TEST_RUN for XDP
programs.
The test uses a BPF program that takes in a return value from XDP
metadata, then reduces the size of the XDP metadata by 4 bytes.
Test cases validate the possible failure cases for passing in invalid
xdp_md contexts, that the return value is successfully passed
in, and that the adjusted metadata is successfully copied out.
Co-developed-by: Cody Haas <chaas@xxxxxxxxxxxxx>
Signed-off-by: Cody Haas <chaas@xxxxxxxxxxxxx>
Co-developed-by: Lisa Watanabe <lwatanabe@xxxxxxxxxxxxx>
Signed-off-by: Lisa Watanabe <lwatanabe@xxxxxxxxxxxxx>
Signed-off-by: Zvi Effron <zeffron@xxxxxxxxxxxxx>
---
.../bpf/prog_tests/xdp_context_test_run.c | 114 ++++++++++++++++++
.../bpf/progs/test_xdp_context_test_run.c | 20 +++
2 files changed, 134 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/xdp_context_test_run.c
create mode 100644 tools/testing/selftests/bpf/progs/test_xdp_context_test_run.c
diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_context_test_run.c b/tools/testing/selftests/bpf/prog_tests/xdp_context_test_run.c
new file mode 100644
index 000000000000..0dbdebbc66ce
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/xdp_context_test_run.c
@@ -0,0 +1,114 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <test_progs.h>
+#include <network_helpers.h>
+#include "test_xdp_context_test_run.skel.h"
+
+void test_xdp_context_test_run(void)
+{
+ struct test_xdp_context_test_run *skel = NULL;
+ char data[sizeof(pkt_v4) + sizeof(__u32)];
+ char buf[128];
+ char bad_ctx[sizeof(struct xdp_md)];
+ struct xdp_md ctx_in, ctx_out;
+ DECLARE_LIBBPF_OPTS(bpf_test_run_opts, opts,
+ .data_in = &data,
+ .data_out = buf,
+ .data_size_in = sizeof(data),
+ .data_size_out = sizeof(buf),
+ .ctx_out = &ctx_out,
+ .ctx_size_out = sizeof(ctx_out),
+ .repeat = 1,
+ );
+ int err, prog_fd;
+
+ skel = test_xdp_context_test_run__open_and_load();
+ if (!ASSERT_OK_PTR(skel, "skel"))
+ return;
+ prog_fd = bpf_program__fd(skel->progs._xdp_context);
+
+ *(__u32 *)data = XDP_PASS;
+ *(struct ipv4_packet *)(data + sizeof(__u32)) = pkt_v4;
+
+ memset(&ctx_in, 0, sizeof(ctx_in));
+ opts.ctx_in = &ctx_in;
+ opts.ctx_size_in = sizeof(ctx_in);
+
+ opts.ctx_in = &ctx_in;
+ opts.ctx_size_in = sizeof(ctx_in);
The above two assignments are redundant.
+ ctx_in.data_meta = 0;
+ ctx_in.data = sizeof(__u32);
+ ctx_in.data_end = ctx_in.data + sizeof(pkt_v4);
+ err = bpf_prog_test_run_opts(prog_fd, &opts);
+ ASSERT_OK(err, "bpf_prog_test_run(test1)");
+ ASSERT_EQ(opts.retval, XDP_PASS, "test1-retval");
+ ASSERT_EQ(opts.data_size_out, sizeof(pkt_v4), "test1-datasize");
+ ASSERT_EQ(opts.ctx_size_out, opts.ctx_size_in, "test1-ctxsize");
+ ASSERT_EQ(ctx_out.data_meta, 0, "test1-datameta");
+ ASSERT_EQ(ctx_out.data, ctx_out.data_meta, "test1-data");
I suggest just to test ctx_out.data == 0. It just happens
the input data - meta = 4 and bpf program adjuested by 4.
If they are not the same, the result won't be equal to data_meta.
+ ASSERT_EQ(ctx_out.data_end, sizeof(pkt_v4), "test1-dataend");
+
+ /* Data past the end of the kernel's struct xdp_md must be 0 */
+ bad_ctx[sizeof(bad_ctx) - 1] = 1;
+ opts.ctx_in = bad_ctx;
+ opts.ctx_size_in = sizeof(bad_ctx);
+ err = bpf_prog_test_run_opts(prog_fd, &opts);
+ ASSERT_EQ(errno, 22, "test2-errno");
+ ASSERT_ERR(err, "bpf_prog_test_run(test2)");
I suggest to drop this test. Basically you did here
is to have non-zero egress_ifindex which is not allowed.
You have a test below.
+
+ /* The egress cannot be specified */
+ ctx_in.egress_ifindex = 1;
+ err = bpf_prog_test_run_opts(prog_fd, &opts);
+ ASSERT_EQ(errno, 22, "test3-errno");
Use EINVAL explicitly? The same for below a few other cases.
+ ASSERT_ERR(err, "bpf_prog_test_run(test3)");
+
+ /* data_meta must reference the start of data */
+ ctx_in.data_meta = sizeof(__u32);
+ ctx_in.data = ctx_in.data_meta;
+ ctx_in.data_end = ctx_in.data + sizeof(pkt_v4);
+ ctx_in.egress_ifindex = 0;
+ err = bpf_prog_test_run_opts(prog_fd, &opts);
+ ASSERT_EQ(errno, 22, "test4-errno");
+ ASSERT_ERR(err, "bpf_prog_test_run(test4)");
+
+ /* Metadata must be 32 bytes or smaller */
+ ctx_in.data_meta = 0;
+ ctx_in.data = sizeof(__u32)*9;
+ ctx_in.data_end = ctx_in.data + sizeof(pkt_v4);
+ err = bpf_prog_test_run_opts(prog_fd, &opts);
+ ASSERT_EQ(errno, 22, "test5-errno");
+ ASSERT_ERR(err, "bpf_prog_test_run(test5)");
This test is not necessary if ctx size should be
<= sizeof(struct xdp_md). So far, I think we can
require it must be sizeof(struct xdp_md). If
in the future, kernel struct xdp_md is extended,
it may be changed to accept both old and new
xdp_md's similar to other uapi data strcture
like struct bpf_prog_info if there is a desire.
In my opinion, the kernel should just stick
to sizeof(struct xdp_md) size since the functionality
is implemented as a *testing* mechanism.
+
+ /* Metadata's size must be a multiple of 4 */
+ ctx_in.data = 3;
+ err = bpf_prog_test_run_opts(prog_fd, &opts);
+ ASSERT_EQ(errno, 22, "test6-errno");
+ ASSERT_ERR(err, "bpf_prog_test_run(test6)");
+
+ /* Total size of data must match data_end - data_meta */
+ ctx_in.data = 0;
+ ctx_in.data_end = sizeof(pkt_v4) - 4;
+ err = bpf_prog_test_run_opts(prog_fd, &opts);
+ ASSERT_EQ(errno, 22, "test7-errno");
+ ASSERT_ERR(err, "bpf_prog_test_run(test7)");
+
+ ctx_in.data_end = sizeof(pkt_v4) + 4;
+ err = bpf_prog_test_run_opts(prog_fd, &opts);
+ ASSERT_EQ(errno, 22, "test8-errno");
+ ASSERT_ERR(err, "bpf_prog_test_run(test8)");
+
+ /* RX queue cannot be specified without specifying an ingress */
+ ctx_in.data_end = sizeof(pkt_v4);
+ ctx_in.ingress_ifindex = 0;
+ ctx_in.rx_queue_index = 1;
+ err = bpf_prog_test_run_opts(prog_fd, &opts);
+ ASSERT_EQ(errno, 22, "test9-errno");
+ ASSERT_ERR(err, "bpf_prog_test_run(test9)");
+
+ ctx_in.ingress_ifindex = 1;
+ ctx_in.rx_queue_index = 1;
+ err = bpf_prog_test_run_opts(prog_fd, &opts);
+ ASSERT_EQ(errno, 22, "test10-errno");
+ ASSERT_ERR(err, "bpf_prog_test_run(test10)");
Why this failure? I guess it is due to device search failure, right?
So this test MAY succeed if the underlying host happens with
a proper configuration with ingress_ifindex = 1 and rx_queue_index = 1,
right?
+
+ test_xdp_context_test_run__destroy(skel);
+}
diff --git a/tools/testing/selftests/bpf/progs/test_xdp_context_test_run.c b/tools/testing/selftests/bpf/progs/test_xdp_context_test_run.c
new file mode 100644
index 000000000000..56fd0995b67c
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_xdp_context_test_run.c
@@ -0,0 +1,20 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+
+SEC("xdp")
+int _xdp_context(struct xdp_md *xdp)
Maybe drop prefix "_" from the function name?
+{
+ void *data = (void *)(unsigned long)xdp->data;
+ __u32 *metadata = (void *)(unsigned long)xdp->data_meta;
The above code is okay as verifier will rewrite correctly with actual
address. But I still suggest to use "long" instead of "unsigned long"
to be consistent with other bpf programs.
+ __u32 ret;
+
+ if (metadata + 1 > data)
+ return XDP_ABORTED;
+ ret = *metadata;
+ if (bpf_xdp_adjust_meta(xdp, 4))
+ return XDP_ABORTED;
+ return ret;
+}
+
+char _license[] SEC("license") = "GPL";
