| Message ID | 20210527201341.7128-4-zeffron@riotgames.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | BPF |
| Headers | show |
| Series | bpf: support input xdp_md context in BPF_PROG_TEST_RUN | expand |
On Thu, May 27, 2021 at 1:14 PM Zvi Effron <zeffron@riotgames.com> 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@riotgames.com> > Signed-off-by: Cody Haas <chaas@riotgames.com> > Co-developed-by: Lisa Watanabe <lwatanabe@riotgames.com> > Signed-off-by: Lisa Watanabe <lwatanabe@riotgames.com> > Signed-off-by: Zvi Effron <zeffron@riotgames.com> > --- > .../bpf/prog_tests/xdp_context_test_run.c | 116 ++++++++++++++++++ > .../bpf/progs/test_xdp_context_test_run.c | 20 +++ > 2 files changed, 136 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..f6d312005b7c > --- /dev/null > +++ b/tools/testing/selftests/bpf/prog_tests/xdp_context_test_run.c > @@ -0,0 +1,116 @@ > +// 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; > + struct bpf_test_run_opts tattr = { see LIBBPF_DECLARE_OPTS, please use it and please call it opts, it's not attribute > + .sz = sizeof(struct bpf_test_run_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; > + > + extra empty line > + 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)); > + tattr.ctx_in = &ctx_in; > + tattr.ctx_size_in = sizeof(ctx_in); > + > + tattr.ctx_in = &ctx_in; > + tattr.ctx_size_in = sizeof(ctx_in); > + 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, &tattr); > + ASSERT_OK(err, "bpf_prog_test_run(test1)"); > + ASSERT_EQ(tattr.retval, XDP_PASS, "test1-retval"); > + ASSERT_EQ(tattr.data_size_out, sizeof(pkt_v4), "test1-datasize"); > + ASSERT_EQ(tattr.ctx_size_out, tattr.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"); > + 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; > + tattr.ctx_in = bad_ctx; > + tattr.ctx_size_in = sizeof(bad_ctx); > + err = bpf_prog_test_run_opts(prog_fd, &tattr); > + ASSERT_ERR(err, "bpf_prog_test_run(test2)"); > + ASSERT_EQ(errno, 22, "test2-errno"); by the time you are checking errno it might get overwritten. If you want to check errno, you have to remember it right after the function returns > + > + /* The egress cannot be specified */ > + ctx_in.egress_ifindex = 1; > + err = bpf_prog_test_run_opts(prog_fd, &tattr); > + ASSERT_ERR(err, "bpf_prog_test_run(test3)"); > + ASSERT_EQ(errno, 22, "test3-errno"); > + [...]
On Thu, May 27, 2021 at 6:28 PM Andrii Nakryiko <andrii.nakryiko@gmail.com> wrote: > > On Thu, May 27, 2021 at 1:14 PM Zvi Effron <zeffron@riotgames.com> wrote: > > > > + > > + /* Data past the end of the kernel's struct xdp_md must be 0 */ > > + bad_ctx[sizeof(bad_ctx) - 1] = 1; > > + tattr.ctx_in = bad_ctx; > > + tattr.ctx_size_in = sizeof(bad_ctx); > > + err = bpf_prog_test_run_opts(prog_fd, &tattr); > > + ASSERT_ERR(err, "bpf_prog_test_run(test2)"); > > + ASSERT_EQ(errno, 22, "test2-errno"); > > by the time you are checking errno it might get overwritten. If you > want to check errno, you have to remember it right after the function > returns Is it sufficient to simply make the errno ASSERT the first thing after the function returns? Or would we still need to preserve it into a local variable?
On Thu, May 27, 2021 at 7:11 PM Zvi Effron <zeffron@riotgames.com> wrote: > > On Thu, May 27, 2021 at 6:28 PM Andrii Nakryiko > <andrii.nakryiko@gmail.com> wrote: > > > > On Thu, May 27, 2021 at 1:14 PM Zvi Effron <zeffron@riotgames.com> wrote: > > > > > > + > > > + /* Data past the end of the kernel's struct xdp_md must be 0 */ > > > + bad_ctx[sizeof(bad_ctx) - 1] = 1; > > > + tattr.ctx_in = bad_ctx; > > > + tattr.ctx_size_in = sizeof(bad_ctx); > > > + err = bpf_prog_test_run_opts(prog_fd, &tattr); > > > + ASSERT_ERR(err, "bpf_prog_test_run(test2)"); > > > + ASSERT_EQ(errno, 22, "test2-errno"); > > > > by the time you are checking errno it might get overwritten. If you > > want to check errno, you have to remember it right after the function > > returns > > Is it sufficient to simply make the errno ASSERT the first thing after > the function returns? Or would we still need to preserve it into a > local variable? Yes, doing ASSERT_EQ(errno, 22, "test2-errno") right after bpf_prog_test_run_opts() will work reliably.
On Thu, May 27, 2021 at 6:28 PM Andrii Nakryiko <andrii.nakryiko@gmail.com> wrote: > > On Thu, May 27, 2021 at 1:14 PM Zvi Effron <zeffron@riotgames.com> wrote: > > > > + /* Data past the end of the kernel's struct xdp_md must be 0 */ > > + bad_ctx[sizeof(bad_ctx) - 1] = 1; > > + tattr.ctx_in = bad_ctx; > > + tattr.ctx_size_in = sizeof(bad_ctx); > > + err = bpf_prog_test_run_opts(prog_fd, &tattr); > > + ASSERT_ERR(err, "bpf_prog_test_run(test2)"); > > + ASSERT_EQ(errno, 22, "test2-errno"); > > by the time you are checking errno it might get overwritten. If you > want to check errno, you have to remember it right after the function > returns > I just noticed that the CHECK macro (which the ASSERT macro wraps) already saves/restores errno. Is this not behavior that can be relied on?
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..f6d312005b7c --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/xdp_context_test_run.c @@ -0,0 +1,116 @@ +// 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; + struct bpf_test_run_opts tattr = { + .sz = sizeof(struct bpf_test_run_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)); + tattr.ctx_in = &ctx_in; + tattr.ctx_size_in = sizeof(ctx_in); + + tattr.ctx_in = &ctx_in; + tattr.ctx_size_in = sizeof(ctx_in); + 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, &tattr); + ASSERT_OK(err, "bpf_prog_test_run(test1)"); + ASSERT_EQ(tattr.retval, XDP_PASS, "test1-retval"); + ASSERT_EQ(tattr.data_size_out, sizeof(pkt_v4), "test1-datasize"); + ASSERT_EQ(tattr.ctx_size_out, tattr.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"); + 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; + tattr.ctx_in = bad_ctx; + tattr.ctx_size_in = sizeof(bad_ctx); + err = bpf_prog_test_run_opts(prog_fd, &tattr); + ASSERT_ERR(err, "bpf_prog_test_run(test2)"); + ASSERT_EQ(errno, 22, "test2-errno"); + + /* The egress cannot be specified */ + ctx_in.egress_ifindex = 1; + err = bpf_prog_test_run_opts(prog_fd, &tattr); + ASSERT_ERR(err, "bpf_prog_test_run(test3)"); + ASSERT_EQ(errno, 22, "test3-errno"); + + /* 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, &tattr); + ASSERT_ERR(err, "bpf_prog_test_run(test4)"); + ASSERT_EQ(errno, 22, "test4-errno"); + + /* 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, &tattr); + ASSERT_ERR(err, "bpf_prog_test_run(test5)"); + ASSERT_EQ(errno, 22, "test5-errno"); + + /* Metadata's size must be a multiple of 4 */ + ctx_in.data = 3; + err = bpf_prog_test_run_opts(prog_fd, &tattr); + ASSERT_ERR(err, "bpf_prog_test_run(test6)"); + ASSERT_EQ(errno, 22, "test6-errno"); + + /* 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, &tattr); + ASSERT_ERR(err, "bpf_prog_test_run(test7)"); + ASSERT_EQ(errno, 22, "test7-errno"); + + ctx_in.data_end = sizeof(pkt_v4) + 4; + err = bpf_prog_test_run_opts(prog_fd, &tattr); + ASSERT_ERR(err, "bpf_prog_test_run(test8)"); + ASSERT_EQ(errno, 22, "test8-errno"); + + /* 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, &tattr); + ASSERT_ERR(err, "bpf_prog_test_run(test9)"); + ASSERT_EQ(errno, 22, "test9-errno"); + + ctx_in.ingress_ifindex = 1; + ctx_in.rx_queue_index = 1; + err = bpf_prog_test_run_opts(prog_fd, &tattr); + ASSERT_ERR(err, "bpf_prog_test_run(test10)"); + ASSERT_EQ(errno, 22, "test10-errno"); + + 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) +{ + void *data = (void *)(unsigned long)xdp->data; + __u32 *metadata = (void *)(unsigned long)xdp->data_meta; + __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";