Add a test that exercises a basic sockmap / sockhash copy using bpf_iter.

Signed-off-by: Lorenz Bauer <lmb@cloudflare.com> --- .../selftests/bpf/prog_tests/sockmap_basic.c | 88 +++++++++++++++++++ tools/testing/selftests/bpf/progs/bpf_iter.h | 9 ++ .../selftests/bpf/progs/bpf_iter_sockmap.c | 57 ++++++++++++ .../selftests/bpf/progs/bpf_iter_sockmap.h | 3 + 4 files changed, 157 insertions(+) create mode 100644 tools/testing/selftests/bpf/progs/bpf_iter_sockmap.c create mode 100644 tools/testing/selftests/bpf/progs/bpf_iter_sockmap.h

Author: lmb

tools/testing/selftests/bpf/prog_tests/sockmap_basic.c

@@ -6,6 +6,9 @@
 #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"
+
+#include "progs/bpf_iter_sockmap.h"
 
 #define TCP_REPAIR19/* TCP sock is under repair right now */
 
@@ -193,6 +196,87 @@ 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, len, src_fd, iter_fd, duration;
+union bpf_iter_link_info linfo = {0};
+__s64 sock_fd[SOCKMAP_MAX_ENTRIES];
+__u32 i, num_sockets, max_elems;
+struct bpf_iter_sockmap *skel;
+struct bpf_map *src, *dst;
+struct bpf_link *link;
+char buf[64];
+
+skel = bpf_iter_sockmap__open_and_load();
+if (CHECK(!skel, "bpf_iter_sockmap__open_and_load", "skeleton open_and_load failed\n"))
+return;
+
+for (i = 0; i < ARRAY_SIZE(sock_fd); i++)
+sock_fd[i] = -1;
+
+/* Make sure we have at least one "empty" entry to test iteration of
+ * an empty slot in an array.
+ */
+num_sockets = ARRAY_SIZE(sock_fd) - 1;
+
+if (map_type == BPF_MAP_TYPE_SOCKMAP) {
+src = skel->maps.sockmap;
+max_elems = bpf_map__max_entries(src);
+} else {
+src = skel->maps.sockhash;
+max_elems = num_sockets;
+}
+
+dst = skel->maps.dst;
+src_fd = bpf_map__fd(src);
+
+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", "failed: %s\n", strerror(errno)))
+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"))
@@ -209,4 +293,8 @@ 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);
 }

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 sock *sk;
+};

tools/testing/selftests/bpf/progs/bpf_iter_sockmap.c

@@ -0,0 +1,57 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2020 Cloudflare */
+#include "bpf_iter.h"
+#include "bpf_tracing_net.h"
+#include "bpf_iter_sockmap.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+#include <errno.h>
+
+char _license[] SEC("license") = "GPL";
+
+struct {
+__uint(type, BPF_MAP_TYPE_SOCKMAP);
+__uint(max_entries, SOCKMAP_MAX_ENTRIES);
+__type(key, __u32);
+__type(value, __u64);
+} sockmap SEC(".maps");
+
+struct {
+__uint(type, BPF_MAP_TYPE_SOCKHASH);
+__uint(max_entries, SOCKMAP_MAX_ENTRIES);
+__type(key, __u32);
+__type(value, __u64);
+} sockhash SEC(".maps");
+
+struct {
+__uint(type, BPF_MAP_TYPE_SOCKHASH);
+__uint(max_entries, SOCKMAP_MAX_ENTRIES);
+__type(key, __u32);
+__type(value, __u64);
+} dst SEC(".maps");
+
+__u32 elems = 0;
+
+SEC("iter/sockmap")
+int copy_sockmap(struct bpf_iter__sockmap *ctx)
+{
+struct sock *sk = ctx->sk;
+__u32 tmp, *key = ctx->key;
+int ret;
+
+if (!key)
+return 0;
+
+elems++;
+
+/* We need a temporary buffer on the stack, since the verifier doesn't
+ * let us use the pointer from the context as an argument to the helper.
+ */
+tmp = *key;
+
+if (sk)
+return bpf_map_update_elem(&dst, &tmp, sk, 0) != 0;
+
+ret = bpf_map_delete_elem(&dst, &tmp);
+return ret && ret != -ENOENT;
+}

tools/testing/selftests/bpf/progs/bpf_iter_sockmap.h

@@ -0,0 +1,3 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#define SOCKMAP_MAX_ENTRIES (64)