selftest/bpf: Simple test for fentry/fexit

Add simple test for fentry and fexit programs around eth_type_trans.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20191114185720.1641606-8-ast@kernel.org

diff --git a/tools/testing/selftests/bpf/prog_tests/kfree_skb.c b/tools/testing/selftests/bpf/prog_tests/kfree_skb.c
index 55d36856e621fa076600bed310ccc950f1e5b14c..7507c8f689bc5c255513991a691481d63304cdbd 100644 (file)
--- a/tools/testing/selftests/bpf/prog_tests/kfree_skb.c
+++ b/tools/testing/selftests/bpf/prog_tests/kfree_skb.c
@@ -60,15 +60,17 @@ void test_kfree_skb(void)
                .file = "./kfree_skb.o",
        };
 
+       struct bpf_link *link = NULL, *link_fentry = NULL, *link_fexit = NULL;
+       struct bpf_map *perf_buf_map, *global_data;
+       struct bpf_program *prog, *fentry, *fexit;
        struct bpf_object *obj, *obj2 = NULL;
        struct perf_buffer_opts pb_opts = {};
        struct perf_buffer *pb = NULL;
-       struct bpf_link *link = NULL;
-       struct bpf_map *perf_buf_map;
-       struct bpf_program *prog;
        int err, kfree_skb_fd;
        bool passed = false;
        __u32 duration = 0;
+       const int zero = 0;
+       bool test_ok[2];
 
        err = bpf_prog_load("./test_pkt_access.o", BPF_PROG_TYPE_SCHED_CLS,
                            &obj, &tattr.prog_fd);
@@ -82,9 +84,28 @@ void test_kfree_skb(void)
        prog = bpf_object__find_program_by_title(obj2, "tp_btf/kfree_skb");
        if (CHECK(!prog, "find_prog", "prog kfree_skb not found\n"))
                goto close_prog;
+       fentry = bpf_object__find_program_by_title(obj2, "fentry/eth_type_trans");
+       if (CHECK(!fentry, "find_prog", "prog eth_type_trans not found\n"))
+               goto close_prog;
+       fexit = bpf_object__find_program_by_title(obj2, "fexit/eth_type_trans");
+       if (CHECK(!fexit, "find_prog", "prog eth_type_trans not found\n"))
+               goto close_prog;
+
+       global_data = bpf_object__find_map_by_name(obj2, "kfree_sk.bss");
+       if (CHECK(!global_data, "find global data", "not found\n"))
+               goto close_prog;
+
        link = bpf_program__attach_raw_tracepoint(prog, NULL);
        if (CHECK(IS_ERR(link), "attach_raw_tp", "err %ld\n", PTR_ERR(link)))
                goto close_prog;
+       link_fentry = bpf_program__attach_trace(fentry);
+       if (CHECK(IS_ERR(link_fentry), "attach fentry", "err %ld\n",
+                 PTR_ERR(link_fentry)))
+               goto close_prog;
+       link_fexit = bpf_program__attach_trace(fexit);
+       if (CHECK(IS_ERR(link_fexit), "attach fexit", "err %ld\n",
+                 PTR_ERR(link_fexit)))
+               goto close_prog;
 
        perf_buf_map = bpf_object__find_map_by_name(obj2, "perf_buf_map");
        if (CHECK(!perf_buf_map, "find_perf_buf_map", "not found\n"))
@@ -108,14 +129,26 @@ void test_kfree_skb(void)
        err = perf_buffer__poll(pb, 100);
        if (CHECK(err < 0, "perf_buffer__poll", "err %d\n", err))
                goto close_prog;
+
        /* make sure kfree_skb program was triggered
         * and it sent expected skb into ring buffer
         */
        CHECK_FAIL(!passed);
+
+       err = bpf_map_lookup_elem(bpf_map__fd(global_data), &zero, test_ok);
+       if (CHECK(err, "get_result",
+                 "failed to get output data: %d\n", err))
+               goto close_prog;
+
+       CHECK_FAIL(!test_ok[0] || !test_ok[1]);
 close_prog:
        perf_buffer__free(pb);
        if (!IS_ERR_OR_NULL(link))
                bpf_link__destroy(link);
+       if (!IS_ERR_OR_NULL(link_fentry))
+               bpf_link__destroy(link_fentry);
+       if (!IS_ERR_OR_NULL(link_fexit))
+               bpf_link__destroy(link_fexit);
        bpf_object__close(obj);
        bpf_object__close(obj2);
 }

diff --git a/tools/testing/selftests/bpf/progs/kfree_skb.c b/tools/testing/selftests/bpf/progs/kfree_skb.c
index f769fdbf6725fc321cbcd45acc52ff8323752bb0..dcc9feac8338b76b439386b9456cd850cdcb1ab5 100644 (file)
--- a/tools/testing/selftests/bpf/progs/kfree_skb.c
+++ b/tools/testing/selftests/bpf/progs/kfree_skb.c
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 // Copyright (c) 2019 Facebook
 #include <linux/bpf.h>
+#include <stdbool.h>
 #include "bpf_helpers.h"
 #include "bpf_endian.h"
 
@@ -116,3 +117,54 @@ int trace_kfree_skb(struct trace_kfree_skb *ctx)
                       &meta, sizeof(meta));
        return 0;
 }
+
+static volatile struct {
+       bool fentry_test_ok;
+       bool fexit_test_ok;
+} result;
+
+struct eth_type_trans_args {
+       struct sk_buff *skb;
+       struct net_device *dev;
+       unsigned short protocol; /* return value available to fexit progs */
+};
+
+SEC("fentry/eth_type_trans")
+int fentry_eth_type_trans(struct eth_type_trans_args *ctx)
+{
+       struct sk_buff *skb = ctx->skb;
+       struct net_device *dev = ctx->dev;
+       int len, ifindex;
+
+       __builtin_preserve_access_index(({
+               len = skb->len;
+               ifindex = dev->ifindex;
+       }));
+
+       /* fentry sees full packet including L2 header */
+       if (len != 74 || ifindex != 1)
+               return 0;
+       result.fentry_test_ok = true;
+       return 0;
+}
+
+SEC("fexit/eth_type_trans")
+int fexit_eth_type_trans(struct eth_type_trans_args *ctx)
+{
+       struct sk_buff *skb = ctx->skb;
+       struct net_device *dev = ctx->dev;
+       int len, ifindex;
+
+       __builtin_preserve_access_index(({
+               len = skb->len;
+               ifindex = dev->ifindex;
+       }));
+
+       /* fexit sees packet without L2 header that eth_type_trans should have
+        * consumed.
+        */
+       if (len != 60 || ctx->protocol != bpf_htons(0x86dd) || ifindex != 1)
+               return 0;
+       result.fexit_test_ok = true;
+       return 0;
+}