[PATCH bpf-next 3/7] selftests: bpf: add MPTCP test base

Mat Martineau
2022-04-20T22:25:22Z

From: Nicolas Rybowski <nicolas.rybowski@tessares.net>

This patch adds a base for MPTCP specific tests.

It is currently limited to the is_mptcp field in case of plain TCP
connection because there is no easy way to get the subflow sk from a msk
in userspace. This implies that we cannot lookup the sk_storage attached
to the subflow sk in the sockops program.

Acked-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Co-developed-by: Geliang Tang <geliang.tang@suse.com>
Signed-off-by: Geliang Tang <geliang.tang@suse.com>
Signed-off-by: Nicolas Rybowski <nicolas.rybowski@tessares.net>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
---
MAINTAINERS | 1 +
tools/testing/selftests/bpf/config | 1 +
tools/testing/selftests/bpf/network_helpers.c | 43 ++++--
tools/testing/selftests/bpf/network_helpers.h | 4 +
.../testing/selftests/bpf/prog_tests/mptcp.c | 136 ++++++++++++++++++
.../testing/selftests/bpf/progs/mptcp_sock.c | 50 +++++++
6 files changed, 227 insertions(+), 8 deletions(-)
create mode 100644 tools/testing/selftests/bpf/prog_tests/mptcp.c
create mode 100644 tools/testing/selftests/bpf/progs/mptcp_sock.c

diff --git a/MAINTAINERS b/MAINTAINERS
index fd768d43e048..01fbdb0e0180 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -13764,6 +13764,7 @@ F: include/net/mptcp.h
F: include/trace/events/mptcp.h
F: include/uapi/linux/mptcp.h
F: net/mptcp/
+F: tools/testing/selftests/bpf/*/*mptcp*.c
F: tools/testing/selftests/net/mptcp/

NETWORKING [TCP]
diff --git a/tools/testing/selftests/bpf/config b/tools/testing/selftests/bpf/config
index 763db63a3890..fe0d3ad6ecd8 100644
--- a/tools/testing/selftests/bpf/config
+++ b/tools/testing/selftests/bpf/config
@@ -53,3 +53,4 @@ CONFIG_NF_DEFRAG_IPV4=y
CONFIG_NF_DEFRAG_IPV6=y
CONFIG_NF_CONNTRACK=y
CONFIG_USERFAULTFD=y
+CONFIG_MPTCP=y
diff --git a/tools/testing/selftests/bpf/network_helpers.c b/tools/testing/selftests/bpf/network_helpers.c
index 2bb1f9b3841d..c9a2e39e34fc 100644
--- a/tools/testing/selftests/bpf/network_helpers.c
+++ b/tools/testing/selftests/bpf/network_helpers.c
@@ -21,6 +21,10 @@
#include "network_helpers.h"
#include "test_progs.h"

+#ifndef IPPROTO_MPTCP
+#define IPPROTO_MPTCP 262
+#endif
+
#define clean_errno() (errno == 0 ? "None" : strerror(errno))
#define log_err(MSG, ...) ({ \
int __save = errno; \
@@ -73,13 +77,13 @@ int settimeo(int fd, int timeout_ms)

#define save_errno_close(fd) ({ int __save = errno; close(fd); errno = __save; })

-static int __start_server(int type, const struct sockaddr *addr,
+static int __start_server(int type, int protocol, const struct sockaddr *addr,
socklen_t addrlen, int timeout_ms, bool reuseport)
{
int on = 1;
int fd;

- fd = socket(addr->sa_family, type, 0);
+ fd = socket(addr->sa_family, type, protocol);
if (fd < 0) {
log_err("Failed to create server socket");
return -1;
@@ -113,8 +117,8 @@ static int __start_server(int type, const struct sockaddr *addr,
return -1;
}

-int start_server(int family, int type, const char *addr_str, __u16 port,
- int timeout_ms)
+static int start_server_proto(int family, int type, int protocol,
+ const char *addr_str, __u16 port, int timeout_ms)
{
struct sockaddr_storage addr;
socklen_t addrlen;
@@ -122,10 +126,23 @@ int start_server(int family, int type, const char *addr_str, __u16 port,
if (make_sockaddr(family, addr_str, port, &addr, &addrlen))
return -1;

- return __start_server(type, (struct sockaddr *)&addr,
+ return __start_server(type, protocol, (struct sockaddr *)&addr,
addrlen, timeout_ms, false);
}

+int start_server(int family, int type, const char *addr_str, __u16 port,
+ int timeout_ms)
+{
+ return start_server_proto(family, type, 0, addr_str, port, timeout_ms);
+}
+
+int start_mptcp_server(int family, const char *addr_str, __u16 port,
+ int timeout_ms)
+{
+ return start_server_proto(family, SOCK_STREAM, IPPROTO_MPTCP, addr_str,
+ port, timeout_ms);
+}
+
int *start_reuseport_server(int family, int type, const char *addr_str,
__u16 port, int timeout_ms, unsigned int nr_listens)
{
@@ -144,7 +161,7 @@ int *start_reuseport_server(int family, int type, const char *addr_str,
if (!fds)
return NULL;

- fds[0] = __start_server(type, (struct sockaddr *)&addr, addrlen,
+ fds[0] = __start_server(type, 0, (struct sockaddr *)&addr, addrlen,
timeout_ms, true);
if (fds[0] == -1)
goto close_fds;
@@ -154,7 +171,7 @@ int *start_reuseport_server(int family, int type, const char *addr_str,
goto close_fds;

for (; nr_fds < nr_listens; nr_fds++) {
- fds[nr_fds] = __start_server(type, (struct sockaddr *)&addr,
+ fds[nr_fds] = __start_server(type, 0, (struct sockaddr *)&addr,
addrlen, timeout_ms, true);
if (fds[nr_fds] == -1)
goto close_fds;
@@ -265,7 +282,7 @@ int connect_to_fd_opts(int server_fd, const struct network_helper_opts *opts)
}

addr_in = (struct sockaddr_in *)&addr;
- fd = socket(addr_in->sin_family, type, 0);
+ fd = socket(addr_in->sin_family, type, opts->protocol);
if (fd < 0) {
log_err("Failed to create client socket");
return -1;
@@ -298,6 +315,16 @@ int connect_to_fd(int server_fd, int timeout_ms)
return connect_to_fd_opts(server_fd, &opts);
}

+int connect_to_mptcp_fd(int server_fd, int timeout_ms)
+{
+ struct network_helper_opts opts = {
+ .timeout_ms = timeout_ms,
+ .protocol = IPPROTO_MPTCP,
+ };
+
+ return connect_to_fd_opts(server_fd, &opts);
+}
+
int connect_fd_to_fd(int client_fd, int server_fd, int timeout_ms)
{
struct sockaddr_storage addr;
diff --git a/tools/testing/selftests/bpf/network_helpers.h b/tools/testing/selftests/bpf/network_helpers.h
index a4b3b2f9877b..e0feb115b2ae 100644
--- a/tools/testing/selftests/bpf/network_helpers.h
+++ b/tools/testing/selftests/bpf/network_helpers.h
@@ -21,6 +21,7 @@ struct network_helper_opts {
const char *cc;
int timeout_ms;
bool must_fail;
+ int protocol;
};

/* ipv4 test vector */
@@ -42,11 +43,14 @@ extern struct ipv6_packet pkt_v6;
int settimeo(int fd, int timeout_ms);
int start_server(int family, int type, const char *addr, __u16 port,
int timeout_ms);
+int start_mptcp_server(int family, const char *addr, __u16 port,
+ int timeout_ms);
int *start_reuseport_server(int family, int type, const char *addr_str,
__u16 port, int timeout_ms,
unsigned int nr_listens);
void free_fds(int *fds, unsigned int nr_close_fds);
int connect_to_fd(int server_fd, int timeout_ms);
+int connect_to_mptcp_fd(int server_fd, int timeout_ms);
int connect_to_fd_opts(int server_fd, const struct network_helper_opts *opts);
int connect_fd_to_fd(int client_fd, int server_fd, int timeout_ms);
int fastopen_connect(int server_fd, const char *data, unsigned int data_len,
diff --git a/tools/testing/selftests/bpf/prog_tests/mptcp.c b/tools/testing/selftests/bpf/prog_tests/mptcp.c
new file mode 100644
index 000000000000..cd548bb2828f
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/mptcp.c
@@ -0,0 +1,136 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2020, Tessares SA. */
+
+#include <test_progs.h>
+#include "cgroup_helpers.h"
+#include "network_helpers.h"
+
+struct mptcp_storage {
+ __u32 invoked;
+ __u32 is_mptcp;
+};
+
+static int verify_sk(int map_fd, int client_fd, const char *msg, __u32 is_mptcp)
+{
+ int err = 0, cfd = client_fd;
+ struct mptcp_storage val;
+
+ if (is_mptcp == 1)
+ return 0;
+
+ if (CHECK_FAIL(bpf_map_lookup_elem(map_fd, &cfd, &val) < 0)) {
+ perror("Failed to read socket storage");
+ return -1;
+ }
+
+ if (val.invoked != 1) {
+ log_err("%s: unexpected invoked count %d != 1",
+ msg, val.invoked);
+ err++;
+ }
+
+ if (val.is_mptcp != 0) {
+ log_err("%s: unexpected bpf_tcp_sock.is_mptcp %d != 0",
+ msg, val.is_mptcp);
+ err++;
+ }
+
+ return err;
+}
+
+static int run_test(int cgroup_fd, int server_fd, bool is_mptcp)
+{
+ int client_fd, prog_fd, map_fd, err;
+ struct bpf_program *prog;
+ struct bpf_object *obj;
+ struct bpf_map *map;
+
+ obj = bpf_object__open("./mptcp_sock.o");
+ if (libbpf_get_error(obj))
+ return -EIO;
+
+ err = bpf_object__load(obj);
+ if (CHECK_FAIL(err))
+ goto out;
+
+ prog = bpf_object__find_program_by_name(obj, "_sockops");
+ if (CHECK_FAIL(!prog)) {
+ err = -EIO;
+ goto out;
+ }
+
+ prog_fd = bpf_program__fd(prog);
+ if (CHECK_FAIL(prog_fd < 0)) {
+ err = -EIO;
+ goto out;
+ }
+
+ map = bpf_object__find_map_by_name(obj, "socket_storage_map");
+ if (CHECK_FAIL(!map)) {
+ err = -EIO;
+ goto out;
+ }
+
+ map_fd = bpf_map__fd(map);
+ if (CHECK_FAIL(map_fd < 0)) {
+ err = -EIO;
+ goto out;
+ }
+
+ err = bpf_prog_attach(prog_fd, cgroup_fd, BPF_CGROUP_SOCK_OPS, 0);
+ if (CHECK_FAIL(err))
+ goto out;
+
+ client_fd = is_mptcp ? connect_to_mptcp_fd(server_fd, 0) :
+ connect_to_fd(server_fd, 0);
+ if (client_fd < 0) {
+ err = -EIO;
+ goto out;
+ }
+
+ err += is_mptcp ? verify_sk(map_fd, client_fd, "MPTCP subflow socket", 1) :
+ verify_sk(map_fd, client_fd, "plain TCP socket", 0);
+
+ close(client_fd);
+
+out:
+ bpf_object__close(obj);
+ return err;
+}
+
+void test_base(void)
+{
+ int server_fd, cgroup_fd;
+
+ cgroup_fd = test__join_cgroup("/mptcp");
+ if (CHECK_FAIL(cgroup_fd < 0))
+ return;
+
+ /* without MPTCP */
+ server_fd = start_server(AF_INET, SOCK_STREAM, NULL, 0, 0);
+ if (CHECK_FAIL(server_fd < 0))
+ goto with_mptcp;
+
+ CHECK_FAIL(run_test(cgroup_fd, server_fd, false));
+
+ close(server_fd);
+
+with_mptcp:
+ /* with MPTCP */
+ server_fd = start_mptcp_server(AF_INET, NULL, 0, 0);
+ if (CHECK_FAIL(server_fd < 0))
+ goto close_cgroup_fd;
+
+ CHECK_FAIL(run_test(cgroup_fd, server_fd, true));
+
+ close(server_fd);
+
+close_cgroup_fd:
+ close(cgroup_fd);
+}
+
+void test_mptcp(void)
+{
+ if (test__start_subtest("base"))
+ test_base();
+}
diff --git a/tools/testing/selftests/bpf/progs/mptcp_sock.c b/tools/testing/selftests/bpf/progs/mptcp_sock.c
new file mode 100644
index 000000000000..0d65fb889d03
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/mptcp_sock.c
@@ -0,0 +1,50 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2020, Tessares SA. */
+
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+
+char _license[] SEC("license") = "GPL";
+__u32 _version SEC("version") = 1;
+
+struct mptcp_storage {
+ __u32 invoked;
+ __u32 is_mptcp;
+};
+
+struct {
+ __uint(type, BPF_MAP_TYPE_SK_STORAGE);
+ __uint(map_flags, BPF_F_NO_PREALLOC);
+ __type(key, int);
+ __type(value, struct mptcp_storage);
+} socket_storage_map SEC(".maps");
+
+SEC("sockops")
+int _sockops(struct bpf_sock_ops *ctx)
+{
+ struct mptcp_storage *storage;
+ struct bpf_tcp_sock *tcp_sk;
+ int op = (int)ctx->op;
+ struct bpf_sock *sk;
+
+ if (op != BPF_SOCK_OPS_TCP_CONNECT_CB)
+ return 1;
+
+ sk = ctx->sk;
+ if (!sk)
+ return 1;
+
+ tcp_sk = bpf_tcp_sock(sk);
+ if (!tcp_sk)
+ return 1;
+
+ storage = bpf_sk_storage_get(&socket_storage_map, sk, 0,
+ BPF_SK_STORAGE_GET_F_CREATE);
+ if (!storage)
+ return 1;
+
+ storage->invoked++;
+ storage->is_mptcp = tcp_sk->is_mptcp;
+
+ return 1;
+}
--
2.36.0