[PATCH v21 bpf-next 13/23] bpf: add multi-buffer support to xdp copy helpers
From: Lorenzo Bianconi <lorenzo@kernel.org>
Date: 2022-01-08 11:54:51
Also in:
bpf
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [networking] (tcx & tc bpf, sock_addr), bpf [security & lsm] (security audit and enforcement using bpf), bpf [selftests] (test runners & infrastructure), bpf [tracing], kernel selftest framework, networking [general], the rest, tracing, xdp (express data path) · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, KP Singh, Matt Bobrowski, Song Liu, Shuah Khan, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Steven Rostedt, Masami Hiramatsu, David S. Miller, Jesper Dangaard Brouer, John Fastabend
From: Eelco Chaudron <echaudro@redhat.com> This patch adds support for multi-buffer for the following helpers: - bpf_xdp_output() - bpf_perf_event_output() Acked-by: Toke Hoiland-Jorgensen <redacted> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Eelco Chaudron <echaudro@redhat.com> Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org> --- kernel/trace/bpf_trace.c | 3 + net/core/filter.c | 57 ++++++- .../selftests/bpf/prog_tests/xdp_bpf2bpf.c | 151 +++++++++++++----- .../selftests/bpf/progs/test_xdp_bpf2bpf.c | 2 +- 4 files changed, 168 insertions(+), 45 deletions(-)
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 21aa30644219..06a9e220069e 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c@@ -1562,6 +1562,7 @@ static const struct bpf_func_proto bpf_perf_event_output_proto_raw_tp = { extern const struct bpf_func_proto bpf_skb_output_proto; extern const struct bpf_func_proto bpf_xdp_output_proto; +extern const struct bpf_func_proto bpf_xdp_get_buff_len_trace_proto; BPF_CALL_3(bpf_get_stackid_raw_tp, struct bpf_raw_tracepoint_args *, args, struct bpf_map *, map, u64, flags)
@@ -1661,6 +1662,8 @@ tracing_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_sock_from_file_proto; case BPF_FUNC_get_socket_cookie: return &bpf_get_socket_ptr_cookie_proto; + case BPF_FUNC_xdp_get_buff_len: + return &bpf_xdp_get_buff_len_trace_proto; #endif case BPF_FUNC_seq_printf: return prog->expected_attach_type == BPF_TRACE_ITER ?
diff --git a/net/core/filter.c b/net/core/filter.c
index dc50e635320c..ce40fdbfc367 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c@@ -3796,6 +3796,15 @@ static const struct bpf_func_proto bpf_xdp_get_buff_len_proto = { .arg1_type = ARG_PTR_TO_CTX, }; +BTF_ID_LIST_SINGLE(bpf_xdp_get_buff_len_bpf_ids, struct, xdp_buff) + +const struct bpf_func_proto bpf_xdp_get_buff_len_trace_proto = { + .func = bpf_xdp_get_buff_len, + .gpl_only = false, + .arg1_type = ARG_PTR_TO_BTF_ID, + .arg1_btf_id = &bpf_xdp_get_buff_len_bpf_ids[0], +}; + static unsigned long xdp_get_metalen(const struct xdp_buff *xdp) { return xdp_data_meta_unsupported(xdp) ? 0 :
@@ -4668,10 +4677,48 @@ static const struct bpf_func_proto bpf_sk_ancestor_cgroup_id_proto = { }; #endif -static unsigned long bpf_xdp_copy(void *dst_buff, const void *src_buff, +static unsigned long bpf_xdp_copy(void *dst_buff, const void *ctx, unsigned long off, unsigned long len) { - memcpy(dst_buff, src_buff + off, len); + struct xdp_buff *xdp = (struct xdp_buff *)ctx; + unsigned long ptr_len, ptr_off = 0; + skb_frag_t *next_frag, *end_frag; + struct skb_shared_info *sinfo; + u8 *ptr_buf; + + if (likely(xdp->data_end - xdp->data >= off + len)) { + memcpy(dst_buff, xdp->data + off, len); + return 0; + } + + sinfo = xdp_get_shared_info_from_buff(xdp); + end_frag = &sinfo->frags[sinfo->nr_frags]; + next_frag = &sinfo->frags[0]; + + ptr_len = xdp->data_end - xdp->data; + ptr_buf = xdp->data; + + while (true) { + if (off < ptr_off + ptr_len) { + unsigned long copy_off = off - ptr_off; + unsigned long copy_len = min(len, ptr_len - copy_off); + + memcpy(dst_buff, ptr_buf + copy_off, copy_len); + + off += copy_len; + len -= copy_len; + dst_buff += copy_len; + } + + if (!len || next_frag == end_frag) + break; + + ptr_off += ptr_len; + ptr_buf = skb_frag_address(next_frag); + ptr_len = skb_frag_size(next_frag); + next_frag++; + } + return 0; }
@@ -4682,11 +4729,11 @@ BPF_CALL_5(bpf_xdp_event_output, struct xdp_buff *, xdp, struct bpf_map *, map, if (unlikely(flags & ~(BPF_F_CTXLEN_MASK | BPF_F_INDEX_MASK))) return -EINVAL; - if (unlikely(!xdp || - xdp_size > (unsigned long)(xdp->data_end - xdp->data))) + + if (unlikely(!xdp || xdp_size > xdp_get_buff_len(xdp))) return -EFAULT; - return bpf_event_output(map, flags, meta, meta_size, xdp->data, + return bpf_event_output(map, flags, meta, meta_size, xdp, xdp_size, bpf_xdp_copy); }
diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_bpf2bpf.c b/tools/testing/selftests/bpf/prog_tests/xdp_bpf2bpf.c
index c98a897ad692..c5cff4f2d9de 100644
--- a/tools/testing/selftests/bpf/prog_tests/xdp_bpf2bpf.c
+++ b/tools/testing/selftests/bpf/prog_tests/xdp_bpf2bpf.c@@ -10,11 +10,20 @@ struct meta { int pkt_len; }; +struct test_ctx_s { + bool passed; + int pkt_size; +}; + +struct test_ctx_s test_ctx; + static void on_sample(void *ctx, int cpu, void *data, __u32 size) { - int duration = 0; struct meta *meta = (struct meta *)data; struct ipv4_packet *trace_pkt_v4 = data + sizeof(*meta); + unsigned char *raw_pkt = data + sizeof(*meta); + struct test_ctx_s *tst_ctx = ctx; + int duration = 0; if (CHECK(size < sizeof(pkt_v4) + sizeof(*meta), "check_size", "size %u < %zu\n",
@@ -25,25 +34,114 @@ static void on_sample(void *ctx, int cpu, void *data, __u32 size) "meta->ifindex = %d\n", meta->ifindex)) return; - if (CHECK(meta->pkt_len != sizeof(pkt_v4), "check_meta_pkt_len", - "meta->pkt_len = %zd\n", sizeof(pkt_v4))) + if (CHECK(meta->pkt_len != tst_ctx->pkt_size, "check_meta_pkt_len", + "meta->pkt_len = %d\n", tst_ctx->pkt_size)) return; if (CHECK(memcmp(trace_pkt_v4, &pkt_v4, sizeof(pkt_v4)), "check_packet_content", "content not the same\n")) return; - *(bool *)ctx = true; + if (meta->pkt_len > sizeof(pkt_v4)) { + for (int i = 0; i < (meta->pkt_len - sizeof(pkt_v4)); i++) { + if (raw_pkt[i + sizeof(pkt_v4)] != (unsigned char)i) { + CHECK(true, "check_packet_content", + "byte %zu does not match %u != %u\n", + i + sizeof(pkt_v4), + raw_pkt[i + sizeof(pkt_v4)], + (unsigned char)i); + break; + } + } + } + + tst_ctx->passed = true; } -void test_xdp_bpf2bpf(void) +#define BUF_SZ 9000 + +static int run_xdp_bpf2bpf_pkt_size(int pkt_fd, struct perf_buffer *pb, + struct test_xdp_bpf2bpf *ftrace_skel, + int pkt_size) { __u32 duration = 0, retval, size; - char buf[128]; + __u8 *buf, *buf_in; + int err, ret = 0; + + if (pkt_size > BUF_SZ || pkt_size < sizeof(pkt_v4)) + return -EINVAL; + + buf_in = malloc(BUF_SZ); + if (CHECK(!buf_in, "buf_in malloc()", "error:%s\n", strerror(errno))) + return -ENOMEM; + + buf = malloc(BUF_SZ); + if (CHECK(!buf, "buf malloc()", "error:%s\n", strerror(errno))) { + ret = -ENOMEM; + goto free_buf_in; + } + + test_ctx.passed = false; + test_ctx.pkt_size = pkt_size; + + memcpy(buf_in, &pkt_v4, sizeof(pkt_v4)); + if (pkt_size > sizeof(pkt_v4)) { + for (int i = 0; i < (pkt_size - sizeof(pkt_v4)); i++) + buf_in[i + sizeof(pkt_v4)] = i; + } + + /* Run test program */ + err = bpf_prog_test_run(pkt_fd, 1, buf_in, pkt_size, + buf, &size, &retval, &duration); + + if (CHECK(err || retval != XDP_PASS || size != pkt_size, + "ipv4", "err %d errno %d retval %d size %d\n", + err, errno, retval, size)) { + ret = err ? err : -EINVAL; + goto free_buf; + } + + /* Make sure bpf_xdp_output() was triggered and it sent the expected + * data to the perf ring buffer. + */ + err = perf_buffer__poll(pb, 100); + if (CHECK(err <= 0, "perf_buffer__poll", "err %d\n", err)) { + ret = -EINVAL; + goto free_buf; + } + + if (CHECK_FAIL(!test_ctx.passed)) { + ret = -EINVAL; + goto free_buf; + } + + /* Verify test results */ + if (CHECK(ftrace_skel->bss->test_result_fentry != if_nametoindex("lo"), + "result", "fentry failed err %llu\n", + ftrace_skel->bss->test_result_fentry)) { + ret = -EINVAL; + goto free_buf; + } + + if (CHECK(ftrace_skel->bss->test_result_fexit != XDP_PASS, "result", + "fexit failed err %llu\n", + ftrace_skel->bss->test_result_fexit)) + ret = -EINVAL; + +free_buf: + free(buf); +free_buf_in: + free(buf_in); + + return ret; +} + +void test_xdp_bpf2bpf(void) +{ int err, pkt_fd, map_fd; - bool passed = false; - struct iphdr iph; - struct iptnl_info value4 = {.family = AF_INET}; + __u32 duration = 0; + int pkt_sizes[] = {sizeof(pkt_v4), 1024, 4100, 8200}; + struct iptnl_info value4 = {.family = AF_INET6}; struct test_xdp *pkt_skel = NULL; struct test_xdp_bpf2bpf *ftrace_skel = NULL; struct vip key4 = {.protocol = 6, .family = AF_INET};
@@ -85,39 +183,14 @@ void test_xdp_bpf2bpf(void) goto out; /* Set up perf buffer */ - pb = perf_buffer__new(bpf_map__fd(ftrace_skel->maps.perf_buf_map), 1, - on_sample, NULL, &passed, NULL); + pb = perf_buffer__new(bpf_map__fd(ftrace_skel->maps.perf_buf_map), 8, + on_sample, NULL, &test_ctx, NULL); if (!ASSERT_OK_PTR(pb, "perf_buf__new")) goto out; - /* Run test program */ - err = bpf_prog_test_run(pkt_fd, 1, &pkt_v4, sizeof(pkt_v4), - buf, &size, &retval, &duration); - memcpy(&iph, buf + sizeof(struct ethhdr), sizeof(iph)); - if (CHECK(err || retval != XDP_TX || size != 74 || - iph.protocol != IPPROTO_IPIP, "ipv4", - "err %d errno %d retval %d size %d\n", - err, errno, retval, size)) - goto out; - - /* Make sure bpf_xdp_output() was triggered and it sent the expected - * data to the perf ring buffer. - */ - err = perf_buffer__poll(pb, 100); - if (CHECK(err < 0, "perf_buffer__poll", "err %d\n", err)) - goto out; - - CHECK_FAIL(!passed); - - /* Verify test results */ - if (CHECK(ftrace_skel->bss->test_result_fentry != if_nametoindex("lo"), - "result", "fentry failed err %llu\n", - ftrace_skel->bss->test_result_fentry)) - goto out; - - CHECK(ftrace_skel->bss->test_result_fexit != XDP_TX, "result", - "fexit failed err %llu\n", ftrace_skel->bss->test_result_fexit); - + for (int i = 0; i < ARRAY_SIZE(pkt_sizes); i++) + run_xdp_bpf2bpf_pkt_size(pkt_fd, pb, ftrace_skel, + pkt_sizes[i]); out: if (pb) perf_buffer__free(pb);
diff --git a/tools/testing/selftests/bpf/progs/test_xdp_bpf2bpf.c b/tools/testing/selftests/bpf/progs/test_xdp_bpf2bpf.c
index 58cf4345f5cc..3379d303f41a 100644
--- a/tools/testing/selftests/bpf/progs/test_xdp_bpf2bpf.c
+++ b/tools/testing/selftests/bpf/progs/test_xdp_bpf2bpf.c@@ -49,7 +49,7 @@ int BPF_PROG(trace_on_entry, struct xdp_buff *xdp) void *data = (void *)(long)xdp->data; meta.ifindex = xdp->rxq->dev->ifindex; - meta.pkt_len = data_end - data; + meta.pkt_len = bpf_xdp_get_buff_len((struct xdp_md *)xdp); bpf_xdp_output(xdp, &perf_buf_map, ((__u64) meta.pkt_len << 32) | BPF_F_CURRENT_CPU,
--
2.33.1