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Mon, 31 Aug 2020 03:58:35 -0700 (PDT) References: <20200828094834.23290-1-lmb@cloudflare.com> <20200828094834.23290-4-lmb@cloudflare.com> User-agent: mu4e 1.1.0; emacs 26.3 From: Jakub Sitnicki To: Lorenz Bauer Cc: ast@kernel.org, yhs@fb.com, daniel@iogearbox.net, john.fastabend@gmail.com, bpf@vger.kernel.org, kernel-team@cloudflare.com Subject: Re: [PATCH bpf-next 3/3] selftests: bpf: Test copying a sockmap via bpf_iter In-reply-to: <20200828094834.23290-4-lmb@cloudflare.com> Date: Mon, 31 Aug 2020 12:58:34 +0200 Message-ID: <87d037rsit.fsf@cloudflare.com> MIME-Version: 1.0 Content-Type: text/plain Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Fri, Aug 28, 2020 at 11:48 AM CEST, Lorenz Bauer wrote: > Add a test that exercises a basic sockmap / sockhash copy using bpf_iter. > > Signed-off-by: Lorenz Bauer > --- > .../selftests/bpf/prog_tests/sockmap_basic.c | 78 +++++++++++++++++++ > tools/testing/selftests/bpf/progs/bpf_iter.h | 9 +++ > .../selftests/bpf/progs/bpf_iter_sockmap.c | 50 ++++++++++++ > 3 files changed, 137 insertions(+) > create mode 100644 tools/testing/selftests/bpf/progs/bpf_iter_sockmap.c > > diff --git a/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c b/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c > index b989f8760f1a..386aecf1f7ff 100644 > --- a/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c > +++ b/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c > @@ -6,6 +6,7 @@ > #include "test_skmsg_load_helpers.skel.h" > #include "test_sockmap_update.skel.h" > #include "test_sockmap_invalid_update.skel.h" > +#include "bpf_iter_sockmap.skel.h" > > #define TCP_REPAIR 19 /* TCP sock is under repair right now */ > > @@ -194,6 +195,79 @@ static void test_sockmap_invalid_update(void) > test_sockmap_invalid_update__destroy(skel); > } > > +static void test_sockmap_copy(enum bpf_map_type map_type) > +{ > + DECLARE_LIBBPF_OPTS(bpf_iter_attach_opts, opts); > + int err, i, len, src_fd, iter_fd, num_sockets, duration; > + struct bpf_iter_sockmap *skel; > + struct bpf_map *src, *dst; > + union bpf_iter_link_info linfo = {0}; > + __s64 sock_fd[2] = {-1, -1}; With just two sockets and sockhash max_entries set to 3 (which means 4 buckets), we're likely not exercising walking the bucket chain in the iterator code. How about a more generous value? > + struct bpf_link *link; > + char buf[64]; > + __u32 max_elems; > + > + skel = bpf_iter_sockmap__open_and_load(); > + if (CHECK(!skel, "bpf_iter_sockmap__open_and_load", > + "skeleton open_and_load failed\n")) > + return; > + > + if (map_type == BPF_MAP_TYPE_SOCKMAP) > + src = skel->maps.sockmap; > + else > + src = skel->maps.sockhash; > + > + dst = skel->maps.dst; > + src_fd = bpf_map__fd(src); > + max_elems = bpf_map__max_entries(src); > + > + num_sockets = ARRAY_SIZE(sock_fd); > + for (i = 0; i < num_sockets; i++) { > + sock_fd[i] = connected_socket_v4(); > + if (CHECK(sock_fd[i] == -1, "connected_socket_v4", "cannot connect\n")) > + goto out; > + > + err = bpf_map_update_elem(src_fd, &i, &sock_fd[i], BPF_NOEXIST); > + if (CHECK(err, "map_update", "map_update failed\n")) Nit: No need to repeat what failed in the message when the tag already says it. In this case the message will look like: test_sockmap_copy:FAIL:map_update map_update failed What would be useful is to include the errno in the message. CHECK() doesn't print it by default. > + goto out; > + } > + > + linfo.map.map_fd = src_fd; > + opts.link_info = &linfo; > + opts.link_info_len = sizeof(linfo); > + link = bpf_program__attach_iter(skel->progs.copy_sockmap, &opts); > + if (CHECK(IS_ERR(link), "attach_iter", "attach_iter failed\n")) > + goto out; > + > + iter_fd = bpf_iter_create(bpf_link__fd(link)); > + if (CHECK(iter_fd < 0, "create_iter", "create_iter failed\n")) > + goto free_link; > + > + /* do some tests */ > + while ((len = read(iter_fd, buf, sizeof(buf))) > 0) > + ; > + if (CHECK(len < 0, "read", "failed: %s\n", strerror(errno))) > + goto close_iter; > + > + /* test results */ > + if (CHECK(skel->bss->elems != max_elems, "elems", "got %u expected %u\n", > + skel->bss->elems, max_elems)) > + goto close_iter; > + > + compare_cookies(src, dst); > + > +close_iter: > + close(iter_fd); > +free_link: > + bpf_link__destroy(link); > +out: > + for (i = 0; i < num_sockets; i++) { > + if (sock_fd[i] >= 0) > + close(sock_fd[i]); > + } > + bpf_iter_sockmap__destroy(skel); > +} > + > void test_sockmap_basic(void) > { > if (test__start_subtest("sockmap create_update_free")) > @@ -210,4 +284,8 @@ void test_sockmap_basic(void) > test_sockmap_update(BPF_MAP_TYPE_SOCKHASH); > if (test__start_subtest("sockmap update in unsafe context")) > test_sockmap_invalid_update(); > + if (test__start_subtest("sockmap copy")) > + test_sockmap_copy(BPF_MAP_TYPE_SOCKMAP); > + if (test__start_subtest("sockhash copy")) > + test_sockmap_copy(BPF_MAP_TYPE_SOCKHASH); > } > diff --git a/tools/testing/selftests/bpf/progs/bpf_iter.h b/tools/testing/selftests/bpf/progs/bpf_iter.h > index c196280df90d..ac32a29f5153 100644 > --- a/tools/testing/selftests/bpf/progs/bpf_iter.h > +++ b/tools/testing/selftests/bpf/progs/bpf_iter.h > @@ -13,6 +13,7 @@ > #define udp6_sock udp6_sock___not_used > #define bpf_iter__bpf_map_elem bpf_iter__bpf_map_elem___not_used > #define bpf_iter__bpf_sk_storage_map bpf_iter__bpf_sk_storage_map___not_used > +#define bpf_iter__sockmap bpf_iter__sockmap___not_used > #include "vmlinux.h" > #undef bpf_iter_meta > #undef bpf_iter__bpf_map > @@ -26,6 +27,7 @@ > #undef udp6_sock > #undef bpf_iter__bpf_map_elem > #undef bpf_iter__bpf_sk_storage_map > +#undef bpf_iter__sockmap > > struct bpf_iter_meta { > struct seq_file *seq; > @@ -96,3 +98,10 @@ struct bpf_iter__bpf_sk_storage_map { > struct sock *sk; > void *value; > }; > + > +struct bpf_iter__sockmap { > + struct bpf_iter_meta *meta; > + struct bpf_map *map; > + void *key; > + struct bpf_sock *sk; > +}; > diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_sockmap.c b/tools/testing/selftests/bpf/progs/bpf_iter_sockmap.c > new file mode 100644 > index 000000000000..1b4268c9cd31 > --- /dev/null > +++ b/tools/testing/selftests/bpf/progs/bpf_iter_sockmap.c > @@ -0,0 +1,50 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* Copyright (c) 2020 Cloudflare */ > +#include "bpf_iter.h" > +#include "bpf_tracing_net.h" > +#include > +#include > + > +char _license[] SEC("license") = "GPL"; > + > +struct { > + __uint(type, BPF_MAP_TYPE_SOCKMAP); > + __uint(max_entries, 3); > + __type(key, __u32); > + __type(value, __u64); > +} sockmap SEC(".maps"); > + > +struct { > + __uint(type, BPF_MAP_TYPE_SOCKMAP); > + __uint(max_entries, 3); > + __type(key, __u32); > + __type(value, __u64); > +} sockhash SEC(".maps"); > + > +struct { > + __uint(type, BPF_MAP_TYPE_SOCKHASH); > + __uint(max_entries, 3); > + __type(key, __u32); > + __type(value, __u64); > +} dst SEC(".maps"); > + > +__u32 elems = 0; > + > +SEC("iter/sockmap") > +int copy_sockmap(struct bpf_iter__sockmap *ctx) > +{ > + __u32 tmp, *key = ctx->key; > + struct bpf_sock *sk = ctx->sk; > + > + if (key == (void *)0) > + return 0; > + > + elems++; > + tmp = *key; Is the tmp variable needed? We never inspect its value directly. Or it illustrates that they key can be modified on copy? > + > + if (sk != (void *)0) > + return bpf_map_update_elem(&dst, &tmp, sk, 0) != 0; > + > + bpf_map_delete_elem(&dst, &tmp); map_delete_elem in theory can fail too. Not sure why were ignoring the error here. > + return 0; > +}