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Message-Id: <20201203213330.1657666-3-revest@google.com>
Date: Thu, 3 Dec 2020 22:33:30 +0100
From: Florent Revest <revest@...omium.org>
To: bpf@...r.kernel.org
Cc: ast@...nel.org, daniel@...earbox.net, andrii@...nel.org,
kpsingh@...omium.org, revest@...gle.com,
linux-kernel@...r.kernel.org
Subject: [PATCH bpf-next v2 3/3] bpf: Add a selftest for the tracing bpf_get_socket_cookie
This builds up on the existing socket cookie test which checks whether
the bpf_get_socket_cookie helpers provide the same value in
cgroup/connect6 and sockops programs for a socket created by the
userspace part of the test.
Adding a tracing program to the existing objects requires a different
attachment strategy and different headers.
Signed-off-by: Florent Revest <revest@...gle.com>
---
.../selftests/bpf/prog_tests/socket_cookie.c | 24 +++++++----
.../selftests/bpf/progs/socket_cookie_prog.c | 41 ++++++++++++++++---
2 files changed, 52 insertions(+), 13 deletions(-)
diff --git a/tools/testing/selftests/bpf/prog_tests/socket_cookie.c b/tools/testing/selftests/bpf/prog_tests/socket_cookie.c
index 53d0c44e7907..e5c5e2ea1deb 100644
--- a/tools/testing/selftests/bpf/prog_tests/socket_cookie.c
+++ b/tools/testing/selftests/bpf/prog_tests/socket_cookie.c
@@ -15,8 +15,8 @@ struct socket_cookie {
void test_socket_cookie(void)
{
+ struct bpf_link *set_link, *update_sockops_link, *update_tracing_link;
socklen_t addr_len = sizeof(struct sockaddr_in6);
- struct bpf_link *set_link, *update_link;
int server_fd, client_fd, cgroup_fd;
struct socket_cookie_prog *skel;
__u32 cookie_expected_value;
@@ -39,15 +39,21 @@ void test_socket_cookie(void)
PTR_ERR(set_link)))
goto close_cgroup_fd;
- update_link = bpf_program__attach_cgroup(skel->progs.update_cookie,
- cgroup_fd);
- if (CHECK(IS_ERR(update_link), "update-link-cg-attach", "err %ld\n",
- PTR_ERR(update_link)))
+ update_sockops_link = bpf_program__attach_cgroup(
+ skel->progs.update_cookie_sockops, cgroup_fd);
+ if (CHECK(IS_ERR(update_sockops_link), "update-sockops-link-cg-attach",
+ "err %ld\n", PTR_ERR(update_sockops_link)))
goto free_set_link;
+ update_tracing_link = bpf_program__attach(
+ skel->progs.update_cookie_tracing);
+ if (CHECK(IS_ERR(update_tracing_link), "update-tracing-link-attach",
+ "err %ld\n", PTR_ERR(update_tracing_link)))
+ goto free_update_sockops_link;
+
server_fd = start_server(AF_INET6, SOCK_STREAM, "::1", 0, 0);
if (CHECK(server_fd < 0, "start_server", "errno %d\n", errno))
- goto free_update_link;
+ goto free_update_tracing_link;
client_fd = connect_to_fd(server_fd, 0);
if (CHECK(client_fd < 0, "connect_to_fd", "errno %d\n", errno))
@@ -71,8 +77,10 @@ void test_socket_cookie(void)
close(client_fd);
close_server_fd:
close(server_fd);
-free_update_link:
- bpf_link__destroy(update_link);
+free_update_tracing_link:
+ bpf_link__destroy(update_tracing_link);
+free_update_sockops_link:
+ bpf_link__destroy(update_sockops_link);
free_set_link:
bpf_link__destroy(set_link);
close_cgroup_fd:
diff --git a/tools/testing/selftests/bpf/progs/socket_cookie_prog.c b/tools/testing/selftests/bpf/progs/socket_cookie_prog.c
index 81e84be6f86d..1f770b732cb1 100644
--- a/tools/testing/selftests/bpf/progs/socket_cookie_prog.c
+++ b/tools/testing/selftests/bpf/progs/socket_cookie_prog.c
@@ -1,11 +1,13 @@
// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2018 Facebook
-#include <linux/bpf.h>
-#include <sys/socket.h>
+#include "vmlinux.h"
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_endian.h>
+#include <bpf/bpf_tracing.h>
+
+#define AF_INET6 10
struct socket_cookie {
__u64 cookie_key;
@@ -19,6 +21,14 @@ struct {
__type(value, struct socket_cookie);
} socket_cookies SEC(".maps");
+/*
+ * These three programs get executed in a row on connect() syscalls. The
+ * userspace side of the test creates a client socket, issues a connect() on it
+ * and then checks that the local storage associated with this socket has:
+ * cookie_value == local_port << 8 | 0xFF
+ * The different parts of this cookie_value are appended by those hooks if they
+ * all agree on the output of bpf_get_socket_cookie().
+ */
SEC("cgroup/connect6")
int set_cookie(struct bpf_sock_addr *ctx)
{
@@ -32,14 +42,14 @@ int set_cookie(struct bpf_sock_addr *ctx)
if (!p)
return 1;
- p->cookie_value = 0xFF;
+ p->cookie_value = 0xF;
p->cookie_key = bpf_get_socket_cookie(ctx);
return 1;
}
SEC("sockops")
-int update_cookie(struct bpf_sock_ops *ctx)
+int update_cookie_sockops(struct bpf_sock_ops *ctx)
{
struct bpf_sock *sk;
struct socket_cookie *p;
@@ -60,9 +70,30 @@ int update_cookie(struct bpf_sock_ops *ctx)
if (p->cookie_key != bpf_get_socket_cookie(ctx))
return 1;
- p->cookie_value = (ctx->local_port << 8) | p->cookie_value;
+ p->cookie_value |= (ctx->local_port << 8);
return 1;
}
+SEC("fexit/inet_stream_connect")
+int BPF_PROG(update_cookie_tracing, struct socket *sock,
+ struct sockaddr *uaddr, int addr_len, int flags)
+{
+ struct socket_cookie *p;
+
+ if (uaddr->sa_family != AF_INET6)
+ return 0;
+
+ p = bpf_sk_storage_get(&socket_cookies, sock->sk, 0, 0);
+ if (!p)
+ return 0;
+
+ if (p->cookie_key != bpf_get_socket_cookie(sock->sk))
+ return 0;
+
+ p->cookie_value |= 0xF0;
+
+ return 0;
+}
+
char _license[] SEC("license") = "GPL";
--
2.29.2.576.ga3fc446d84-goog
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