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Message-ID: <20250825193918.3445531-7-ameryhung@gmail.com>
Date: Mon, 25 Aug 2025 12:39:17 -0700
From: Amery Hung <ameryhung@...il.com>
To: bpf@...r.kernel.org
Cc: netdev@...r.kernel.org,
alexei.starovoitov@...il.com,
andrii@...nel.org,
daniel@...earbox.net,
kuba@...nel.org,
martin.lau@...nel.org,
mohsin.bashr@...il.com,
saeedm@...dia.com,
tariqt@...dia.com,
mbloch@...dia.com,
maciej.fijalkowski@...el.com,
kernel-team@...a.com
Subject: [RFC bpf-next v1 6/7] selftests/bpf: Test bpf_xdp_pull_data
Test bpf_xdp_pull_data() with xdp packets with different layouts. The
xdp bpf program first checks if the layout is as expected. Then, it
calls bpf_xdp_pull_data(). Finally, it checks the 0xbb marker at offset
1024 using directly packet access.
Signed-off-by: Amery Hung <ameryhung@...il.com>
---
.../selftests/bpf/prog_tests/xdp_pull_data.c | 96 +++++++++++++++++++
.../selftests/bpf/progs/test_xdp_pull_data.c | 36 +++++++
2 files changed, 132 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/xdp_pull_data.c
create mode 100644 tools/testing/selftests/bpf/progs/test_xdp_pull_data.c
diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_pull_data.c b/tools/testing/selftests/bpf/prog_tests/xdp_pull_data.c
new file mode 100644
index 000000000000..2cd18e15d47e
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/xdp_pull_data.c
@@ -0,0 +1,96 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <test_progs.h>
+#include <network_helpers.h>
+#include "test_xdp_pull_data.skel.h"
+
+/* xdp_pull_data_prog will directly read a marker 0xbb stored at buf[1024]
+ * so caller expecting XDP_PASS should always pass pull_len no less than 1024
+ */
+void test_xdp_pull_data_common(struct test_xdp_pull_data *skel,
+ int buf_len, int linear_len,
+ int pull_len, int retval)
+{
+ LIBBPF_OPTS(bpf_test_run_opts, topts);
+ struct xdp_md ctx = {};
+ int prog_fd, err;
+ __u8 *buf;
+
+ buf = calloc(buf_len, sizeof(__u8));
+ if (!ASSERT_OK_PTR(buf, "calloc buf"))
+ return;
+
+ buf[1023] = 0xaa;
+ buf[1024] = 0xbb;
+ buf[1025] = 0xcc;
+
+ topts.data_in = buf;
+ topts.data_out = buf;
+ topts.data_size_in = buf_len;
+ topts.data_size_out = buf_len;
+ ctx.data_end = linear_len;
+ topts.ctx_in = &ctx;
+ topts.ctx_out = &ctx;
+ topts.ctx_size_in = sizeof(ctx);
+ topts.ctx_size_out = sizeof(ctx);
+
+ skel->bss->linear_len = linear_len;
+ skel->bss->pull_len = pull_len;
+
+ prog_fd = bpf_program__fd(skel->progs.xdp_pull_data_prog);
+ err = bpf_prog_test_run_opts(prog_fd, &topts);
+ ASSERT_OK(err, "bpf_prog_test_run_opts");
+ ASSERT_EQ(topts.retval, retval, "xdp_pull_data_prog retval");
+
+ if (retval == XDP_DROP)
+ goto out;
+
+ ASSERT_EQ(ctx.data_end, pull_len, "linear data size");
+ ASSERT_EQ(topts.data_size_out, buf_len, "linear + non-linear data size");
+ /* Make sure data around xdp->data_end was not messed up by
+ * bpf_xdp_pull_data()
+ */
+ ASSERT_EQ(buf[1023], 0xaa, "buf[1023]");
+ ASSERT_EQ(buf[1024], 0xbb, "buf[1024]");
+ ASSERT_EQ(buf[1025], 0xcc, "buf[1025]");
+out:
+ free(buf);
+}
+
+static void test_xdp_pull_data_basic(void)
+{
+ struct test_xdp_pull_data *skel;
+ u32 page_size;
+
+ skel = test_xdp_pull_data__open_and_load();
+ if (!ASSERT_OK_PTR(skel, "test_xdp_pull_data__open_and_load"))
+ return;
+
+ page_size = sysconf(_SC_PAGE_SIZE);
+
+ /* linear xdp pkt, pull 0 byte */
+ test_xdp_pull_data_common(skel, 2048, 2048, 2048, XDP_PASS);
+ /* multi-buf pkt, pull results in linear xdp pkt */
+ test_xdp_pull_data_common(skel, 2048, 1024, 2048, XDP_PASS);
+ /* multi-buf pkt, pull 1 byte to linear data area */
+ test_xdp_pull_data_common(skel, 9000, 1024, 1025, XDP_PASS);
+ /* multi-buf pkt, pull 0 byte to linear data area */
+ test_xdp_pull_data_common(skel, 9000, 1025, 1025, XDP_PASS);
+
+ /* linear xdp pkt, pull more than total data len */
+ test_xdp_pull_data_common(skel, 2048, 2048, 2049, XDP_DROP);
+ /* multi-buf pkt with no space left in linear data area.
+ * Since ctx.data_end (4096) > max_data_sz, bpf_prog_test_run_xdp()
+ * will fill the whole linear data area and put the reset into a
+ * fragment.
+ */
+ test_xdp_pull_data_common(skel, page_size, page_size, page_size, XDP_DROP);
+
+ test_xdp_pull_data__destroy(skel);
+}
+
+void test_xdp_pull_data(void)
+{
+ if (test__start_subtest("xdp_pull_data"))
+ test_xdp_pull_data_basic();
+}
diff --git a/tools/testing/selftests/bpf/progs/test_xdp_pull_data.c b/tools/testing/selftests/bpf/progs/test_xdp_pull_data.c
new file mode 100644
index 000000000000..f32e6b4a79f5
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_xdp_pull_data.c
@@ -0,0 +1,36 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+
+int _version SEC("version") = 1;
+
+int linear_len;
+int pull_len;
+
+SEC("xdp.frags")
+int xdp_pull_data_prog(struct xdp_md *xdp)
+{
+ __u8 *data_end = (void *)(long)xdp->data_end;
+ __u8 *data = (void *)(long)xdp->data;
+ __u8 *val_p;
+ int err;
+
+ if (linear_len != data_end - data)
+ return XDP_DROP;
+
+ err = bpf_xdp_pull_data(xdp, pull_len, 0);
+ if (err)
+ return XDP_DROP;
+
+ val_p = (void *)(long)xdp->data + 1024;
+ if (val_p + 1 > (void *)(long)xdp->data_end)
+ return XDP_DROP;
+
+ if (*val_p != 0xbb)
+ return XDP_DROP;
+
+ return XDP_PASS;
+}
+
+char _license[] SEC("license") = "GPL";
--
2.47.3
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