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Message-ID: <16a158b4-5e85-8ad3-3389-7687add809d1@fb.com>
Date: Thu, 21 May 2020 11:23:12 -0700
From: Yonghong Song <yhs@...com>
To: John Fastabend <john.fastabend@...il.com>, <ast@...nel.org>,
<daniel@...earbox.net>
CC: <lmb@...udflare.com>, <bpf@...r.kernel.org>,
<jakub@...udflare.com>, <netdev@...r.kernel.org>
Subject: Re: [bpf-next PATCH v3 4/5] bpf: selftests, add sk_msg helpers load
and attach test
On 5/21/20 7:35 AM, John Fastabend wrote:
> The test itself is not particularly useful but it encodes a common
> pattern we have.
>
> Namely do a sk storage lookup then depending on data here decide if
> we need to do more work or alternatively allow packet to PASS. Then
> if we need to do more work consult task_struct for more information
> about the running task. Finally based on this additional information
> drop or pass the data. In this case the suspicious check is not so
> realisitic but it encodes the general pattern and uses the helpers
> so we test the workflow.
>
> This is a load test to ensure verifier correctly handles this case.
>
> Signed-off-by: John Fastabend <john.fastabend@...il.com>
> ---
> .../selftests/bpf/prog_tests/sockmap_basic.c | 57 ++++++++++++++++++++
> .../selftests/bpf/progs/test_skmsg_load_helpers.c | 48 +++++++++++++++++
> 2 files changed, 105 insertions(+)
> create mode 100644 tools/testing/selftests/bpf/progs/test_skmsg_load_helpers.c
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c b/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c
> index aa43e0b..cacb4ad 100644
> --- a/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c
> +++ b/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c
> @@ -1,13 +1,46 @@
> // SPDX-License-Identifier: GPL-2.0
> // Copyright (c) 2020 Cloudflare
> +#include <error.h>
>
> #include "test_progs.h"
> +#include "test_skmsg_load_helpers.skel.h"
>
> #define TCP_REPAIR 19 /* TCP sock is under repair right now */
>
> #define TCP_REPAIR_ON 1
> #define TCP_REPAIR_OFF_NO_WP -1 /* Turn off without window probes */
>
> +#define _FAIL(errnum, fmt...) \
> + ({ \
> + error_at_line(0, (errnum), __func__, __LINE__, fmt); \
> + CHECK_FAIL(true); \
> + })
> +#define FAIL(fmt...) _FAIL(0, fmt)
> +#define FAIL_ERRNO(fmt...) _FAIL(errno, fmt)
> +#define FAIL_LIBBPF(err, msg) \
> + ({ \
> + char __buf[MAX_STRERR_LEN]; \
> + libbpf_strerror((err), __buf, sizeof(__buf)); \
> + FAIL("%s: %s", (msg), __buf); \
> + })
Can we use existing macros in test_progs.h?
This will be consistent with other test_progs selftests.
> +
> +#define xbpf_prog_attach(prog, target, type, flags) \
> + ({ \
> + int __ret = \
> + bpf_prog_attach((prog), (target), (type), (flags)); \
> + if (__ret == -1) \
> + FAIL_ERRNO("prog_attach(" #type ")"); \
> + __ret; \
> + })
> +
> +#define xbpf_prog_detach2(prog, target, type) \
> + ({ \
> + int __ret = bpf_prog_detach2((prog), (target), (type)); \
> + if (__ret == -1) \
> + FAIL_ERRNO("prog_detach2(" #type ")"); \
> + __ret; \
> + })
The above xbpf_prog_attach() and xbpf_prog_detach2()
are only called once, maybe fold into the calling function itself?
> +
> static int connected_socket_v4(void)
> {
> struct sockaddr_in addr = {
> @@ -70,10 +103,34 @@ static void test_sockmap_create_update_free(enum bpf_map_type map_type)
> close(s);
> }
>
> +static void test_skmsg_helpers(enum bpf_map_type map_type)
> +{
> + struct test_skmsg_load_helpers *skel;
> + int err, map, verdict;
> +
> + skel = test_skmsg_load_helpers__open_and_load();
> + if (!skel) {
> + FAIL("skeleton open/load failed");
> + return;
> + }
> +
> + verdict = bpf_program__fd(skel->progs.prog_msg_verdict);
> + map = bpf_map__fd(skel->maps.sock_map);
> +
> + err = xbpf_prog_attach(verdict, map, BPF_SK_MSG_VERDICT, 0);
> + if (err)
> + return;
> + xbpf_prog_detach2(verdict, map, BPF_SK_MSG_VERDICT);
> +}
> +
> void test_sockmap_basic(void)
> {
> if (test__start_subtest("sockmap create_update_free"))
> test_sockmap_create_update_free(BPF_MAP_TYPE_SOCKMAP);
> if (test__start_subtest("sockhash create_update_free"))
> test_sockmap_create_update_free(BPF_MAP_TYPE_SOCKHASH);
> + if (test__start_subtest("sockmap sk_msg load helpers"))
> + test_skmsg_helpers(BPF_MAP_TYPE_SOCKMAP);
> + if (test__start_subtest("sockhash sk_msg load helpers"))
> + test_skmsg_helpers(BPF_MAP_TYPE_SOCKHASH);
> }
> diff --git a/tools/testing/selftests/bpf/progs/test_skmsg_load_helpers.c b/tools/testing/selftests/bpf/progs/test_skmsg_load_helpers.c
> new file mode 100644
> index 0000000..b68eb6c
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/progs/test_skmsg_load_helpers.c
> @@ -0,0 +1,48 @@
> +// SPDX-License-Identifier: GPL-2.0
> +// Copyright (c) 2020 Isovalent, Inc.
> +#include "vmlinux.h"
> +#include <bpf/bpf_helpers.h>
> +
> +struct {
> + __uint(type, BPF_MAP_TYPE_SOCKMAP);
> + __uint(max_entries, 2);
> + __type(key, __u32);
> + __type(value, __u64);
> +} sock_map SEC(".maps");
> +
> +struct {
> + __uint(type, BPF_MAP_TYPE_SOCKHASH);
> + __uint(max_entries, 2);
> + __type(key, __u32);
> + __type(value, __u64);
> +} sock_hash SEC(".maps");
> +
> +struct {
> + __uint(type, BPF_MAP_TYPE_SK_STORAGE);
> + __uint(map_flags, BPF_F_NO_PREALLOC);
> + __type(key, __u32);
> + __type(value, __u64);
> +} socket_storage SEC(".maps");
> +
> +SEC("sk_msg")
> +int prog_msg_verdict(struct sk_msg_md *msg)
> +{
> + struct task_struct *task = (struct task_struct *)bpf_get_current_task();
> + int verdict = SK_PASS;
> + __u32 pid, tpid;
> + __u64 *sk_stg;
> +
> + pid = bpf_get_current_pid_tgid() >> 32;
> + sk_stg = bpf_sk_storage_get(&socket_storage, msg->sk, 0, BPF_SK_STORAGE_GET_F_CREATE);
> + if (!sk_stg)
> + return SK_DROP;
> + *sk_stg = pid;
> + bpf_probe_read_kernel(&tpid , sizeof(tpid), &task->tgid);
> + if (pid != tpid)
> + verdict = SK_DROP;
> + bpf_sk_storage_delete(&socket_storage, (void *)msg->sk);
> + return verdict;
> +}
> +
> +int _version SEC("version") = 1;
> +char _license[] SEC("license") = "GPL";
>
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