[PATCH bpf-next v1 5/5] selftests/bpf: Update xdp_adjust_frags to use bpf_packet_pointer
From: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Date: 2022-03-06 23:43:38
Also in:
bpf
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [selftests] (test runners & infrastructure), kernel selftest framework, the rest, xdp (express data path) · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Shuah Khan, Linus Torvalds, David S. Miller, Jakub Kicinski, Jesper Dangaard Brouer, John Fastabend
Test that in case of linear region, we always are able to do DPA without any errors. Note how offset is clamped to range [0, 0xffff] and len is a constant. Ensure that helper vs DPA is detected and tested. Add a force_helper mode, that forces use of bpf_xdp_load_bytes and bpf_xdp_store_bytes instead of using bpf_packet_pointer, even for contiguous regions, to make sure that case keeps working. Also, we can take this opportunity to convert it to use BPF skeleton. Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> --- .../bpf/prog_tests/xdp_adjust_frags.c | 46 +++++++++++++------ .../bpf/progs/test_xdp_update_frags.c | 46 +++++++++++++------ 2 files changed, 65 insertions(+), 27 deletions(-)
diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_adjust_frags.c b/tools/testing/selftests/bpf/prog_tests/xdp_adjust_frags.c
index 2f033da4cd45..cfb50a575b11 100644
--- a/tools/testing/selftests/bpf/prog_tests/xdp_adjust_frags.c
+++ b/tools/testing/selftests/bpf/prog_tests/xdp_adjust_frags.c@@ -2,26 +2,24 @@ #include <test_progs.h> #include <network_helpers.h> -static void test_xdp_update_frags(void) +#include "test_xdp_update_frags.skel.h" + +static void test_xdp_update_frags(bool force_helper) { - const char *file = "./test_xdp_update_frags.o"; int err, prog_fd, max_skb_frags, buf_size, num; - struct bpf_program *prog; - struct bpf_object *obj; + LIBBPF_OPTS(bpf_test_run_opts, topts); + struct test_xdp_update_frags *skel; __u32 *offset; __u8 *buf; FILE *f; - LIBBPF_OPTS(bpf_test_run_opts, topts); - obj = bpf_object__open(file); - if (libbpf_get_error(obj)) + skel = test_xdp_update_frags__open_and_load(); + if (!ASSERT_OK_PTR(skel, "test_xdp_update_frags__open_and_load")) return; - prog = bpf_object__next_program(obj, NULL); - if (bpf_object__load(obj)) - return; + skel->bss->force_helper = force_helper; - prog_fd = bpf_program__fd(prog); + prog_fd = bpf_program__fd(skel->progs.xdp_adjust_frags); buf = malloc(128); if (!ASSERT_OK_PTR(buf, "alloc buf 128b"))
@@ -45,6 +43,13 @@ static void test_xdp_update_frags(void) ASSERT_EQ(topts.retval, XDP_PASS, "xdp_update_frag retval"); ASSERT_EQ(buf[16], 0xbb, "xdp_update_frag buf[16]"); ASSERT_EQ(buf[31], 0xbb, "xdp_update_frag buf[31]"); + if (force_helper) { + ASSERT_EQ(skel->bss->used_dpa, false, "did not use DPA"); + ASSERT_EQ(skel->bss->used_helper, true, "used helper"); + } else { + ASSERT_EQ(skel->bss->used_dpa, true, "used DPA"); + ASSERT_EQ(skel->bss->used_helper, false, "did not use helper"); + } free(buf);
@@ -70,6 +75,13 @@ static void test_xdp_update_frags(void) ASSERT_EQ(topts.retval, XDP_PASS, "xdp_update_frag retval"); ASSERT_EQ(buf[5000], 0xbb, "xdp_update_frag buf[5000]"); ASSERT_EQ(buf[5015], 0xbb, "xdp_update_frag buf[5015]"); + if (force_helper) { + ASSERT_EQ(skel->bss->used_dpa, false, "did not use DPA"); + ASSERT_EQ(skel->bss->used_helper, true, "used helper"); + } else { + ASSERT_EQ(skel->bss->used_dpa, true, "used DPA"); + ASSERT_EQ(skel->bss->used_helper, false, "did not use helper"); + } memset(buf, 0, 9000); offset = (__u32 *)buf;
@@ -84,6 +96,8 @@ static void test_xdp_update_frags(void) ASSERT_EQ(topts.retval, XDP_PASS, "xdp_update_frag retval"); ASSERT_EQ(buf[3510], 0xbb, "xdp_update_frag buf[3510]"); ASSERT_EQ(buf[3525], 0xbb, "xdp_update_frag buf[3525]"); + ASSERT_EQ(skel->bss->used_dpa, false, "did not use DPA"); + ASSERT_EQ(skel->bss->used_helper, true, "used helper"); memset(buf, 0, 9000); offset = (__u32 *)buf;
@@ -98,6 +112,8 @@ static void test_xdp_update_frags(void) ASSERT_EQ(topts.retval, XDP_PASS, "xdp_update_frag retval"); ASSERT_EQ(buf[7606], 0xbb, "xdp_update_frag buf[7606]"); ASSERT_EQ(buf[7621], 0xbb, "xdp_update_frag buf[7621]"); + ASSERT_EQ(skel->bss->used_dpa, false, "did not use DPA"); + ASSERT_EQ(skel->bss->used_helper, true, "used helper"); free(buf);
@@ -136,11 +152,13 @@ static void test_xdp_update_frags(void) "unsupported buf size, possible non-default /proc/sys/net/core/max_skb_flags?"); free(buf); out: - bpf_object__close(obj); + test_xdp_update_frags__destroy(skel); } void test_xdp_adjust_frags(void) { - if (test__start_subtest("xdp_adjust_frags")) - test_xdp_update_frags(); + if (test__start_subtest("xdp_adjust_frags-force-nodpa")) + test_xdp_update_frags(true); + if (test__start_subtest("xdp_adjust_frags-dpa+memcpy")) + test_xdp_update_frags(false); }
diff --git a/tools/testing/selftests/bpf/progs/test_xdp_update_frags.c b/tools/testing/selftests/bpf/progs/test_xdp_update_frags.c
index 2a3496d8e327..1ad5c45e06e0 100644
--- a/tools/testing/selftests/bpf/progs/test_xdp_update_frags.c
+++ b/tools/testing/selftests/bpf/progs/test_xdp_update_frags.c@@ -4,37 +4,57 @@ * modify it under the terms of version 2 of the GNU General Public * License as published by the Free Software Foundation. */ -#include <linux/bpf.h> -#include <linux/if_ether.h> +#include <vmlinux.h> #include <bpf/bpf_helpers.h> int _version SEC("version") = 1; +bool force_helper; +bool used_dpa; +bool used_helper; + +#define XDP_LEN 16 + SEC("xdp.frags") int xdp_adjust_frags(struct xdp_md *xdp) { __u8 *data_end = (void *)(long)xdp->data_end; __u8 *data = (void *)(long)xdp->data; - __u8 val[16] = {}; + __u8 val[XDP_LEN] = {}; + __u8 *ptr = NULL; __u32 offset; int err; + used_dpa = false; + used_helper = false; + if (data + sizeof(__u32) > data_end) return XDP_DROP; offset = *(__u32 *)data; - err = bpf_xdp_load_bytes(xdp, offset, val, sizeof(val)); - if (err < 0) + offset &= 0xffff; + if (!force_helper) + ptr = bpf_packet_pointer(xdp, offset, XDP_LEN); + if (!ptr) { + used_helper = true; + err = bpf_xdp_load_bytes(xdp, offset, val, sizeof(val)); + if (err < 0) + return XDP_DROP; + ptr = val; + } else { + used_dpa = true; + } + + if (ptr[0] != 0xaa || ptr[15] != 0xaa) /* marker */ return XDP_DROP; - if (val[0] != 0xaa || val[15] != 0xaa) /* marker */ - return XDP_DROP; - - val[0] = 0xbb; /* update the marker */ - val[15] = 0xbb; - err = bpf_xdp_store_bytes(xdp, offset, val, sizeof(val)); - if (err < 0) - return XDP_DROP; + ptr[0] = 0xbb; /* update the marker */ + ptr[15] = 0xbb; + if (ptr == val) { + err = bpf_xdp_store_bytes(xdp, offset, val, sizeof(val)); + if (err < 0) + return XDP_DROP; + } return XDP_PASS; }
--
2.35.1