diff mbox series

[bpf-next,v2,4/5] bpf: selftests: add MPTCP test base

Message ID 20200911143022.414783-4-nicolas.rybowski@tessares.net
State New
Headers show
Series [bpf-next,v2,1/5] bpf: expose is_mptcp flag to bpf_tcp_sock | expand

Commit Message

Nicolas Rybowski Sept. 11, 2020, 2:30 p.m. UTC
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 for the moment 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>
Signed-off-by: Nicolas Rybowski <nicolas.rybowski@tessares.net>
---

Notes:
    v1 -> v2:
    - new patch: mandatory selftests (Alexei)

 tools/testing/selftests/bpf/config            |   1 +
 tools/testing/selftests/bpf/network_helpers.c |  37 +++++-
 tools/testing/selftests/bpf/network_helpers.h |   3 +
 .../testing/selftests/bpf/prog_tests/mptcp.c  | 119 ++++++++++++++++++
 tools/testing/selftests/bpf/progs/mptcp.c     |  48 +++++++
 5 files changed, 203 insertions(+), 5 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/mptcp.c
 create mode 100644 tools/testing/selftests/bpf/progs/mptcp.c

Comments

Song Liu Sept. 14, 2020, 6:07 p.m. UTC | #1
On Fri, Sep 11, 2020 at 8:02 AM Nicolas Rybowski
<nicolas.rybowski@tessares.net> wrote:
>
> 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 for the moment 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>
> Signed-off-by: Nicolas Rybowski <nicolas.rybowski@tessares.net>

Acked-by: Song Liu <songliubraving@fb.com>

With some nitpicks below.

> ---
>
> Notes:
>     v1 -> v2:
>     - new patch: mandatory selftests (Alexei)
>
[...]
>                      int timeout_ms);
> 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..0e65d64868e9
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/prog_tests/mptcp.c
> @@ -0,0 +1,119 @@
> +// SPDX-License-Identifier: GPL-2.0
> +#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;
> +
> +       /* Currently there is no easy way to get back the subflow sk from the MPTCP
> +        * sk, thus we cannot access here the sk_storage associated to the subflow
> +        * sk. Also, there is no sk_storage associated with the MPTCP sk since it
> +        * does not trigger sockops events.
> +        * We silently pass this situation at the moment.
> +        */
> +       if (is_mptcp == 1)
> +               return 0;
> +
> +       if (CHECK_FAIL(bpf_map_lookup_elem(map_fd, &cfd, &val) < 0)) {
> +               perror("Failed to read socket storage");

Maybe simplify this with CHECK(), which contains a customized error message?
Same for some other calls.

> +               return -1;
> +       }
> +
> +       if (val.invoked != 1) {
> +               log_err("%s: unexpected invoked count %d != %d",
> +                       msg, val.invoked, 1);
> +               err++;
> +       }
> +
> +       if (val.is_mptcp != is_mptcp) {
> +               log_err("%s: unexpected bpf_tcp_sock.is_mptcp %d != %d",
> +                       msg, val.is_mptcp, is_mptcp);
> +               err++;
> +       }
> +
> +       return err;
> +}
> +
> +static int run_test(int cgroup_fd, int server_fd, bool is_mptcp)
[...]

> +
> +       client_fd = is_mptcp ? connect_to_mptcp_fd(server_fd, 0) :
> +                              connect_to_fd(server_fd, 0);
> +       if (client_fd < 0) {
> +               err = -1;
> +               goto close_client_fd;

This should be "goto close_bpf_object;", and we don't really need the label
close_client_fd.

> +       }
> +
> +       err += is_mptcp ? verify_sk(map_fd, client_fd, "MPTCP subflow socket", 1) :

It doesn't really change the logic, but I guess we only need "err = xxx"?

> +                         verify_sk(map_fd, client_fd, "plain TCP socket", 0);
> +
> +close_client_fd:
> +       close(client_fd);
> +
> +close_bpf_object:
> +       bpf_object__close(obj);
> +       return err;
> +}
> +
Nicolas Rybowski Sept. 15, 2020, 4:35 p.m. UTC | #2
Hi Song,

Thanks for the feedback !

On Mon, Sep 14, 2020 at 8:07 PM Song Liu <song@kernel.org> wrote:
>
> On Fri, Sep 11, 2020 at 8:02 AM Nicolas Rybowski
> <nicolas.rybowski@tessares.net> wrote:
> >
> > 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 for the moment 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>
> > Signed-off-by: Nicolas Rybowski <nicolas.rybowski@tessares.net>
>
> Acked-by: Song Liu <songliubraving@fb.com>
>
> With some nitpicks below.
>
> > ---
> >
> > Notes:
> >     v1 -> v2:
> >     - new patch: mandatory selftests (Alexei)
> >
> [...]
> >                      int timeout_ms);
> > 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..0e65d64868e9
> > --- /dev/null
> > +++ b/tools/testing/selftests/bpf/prog_tests/mptcp.c
> > @@ -0,0 +1,119 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +#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;
> > +
> > +       /* Currently there is no easy way to get back the subflow sk from the MPTCP
> > +        * sk, thus we cannot access here the sk_storage associated to the subflow
> > +        * sk. Also, there is no sk_storage associated with the MPTCP sk since it
> > +        * does not trigger sockops events.
> > +        * We silently pass this situation at the moment.
> > +        */
> > +       if (is_mptcp == 1)
> > +               return 0;
> > +
> > +       if (CHECK_FAIL(bpf_map_lookup_elem(map_fd, &cfd, &val) < 0)) {
> > +               perror("Failed to read socket storage");
>
> Maybe simplify this with CHECK(), which contains a customized error message?
> Same for some other calls.
>

The whole logic here is strongly inspired from prog_tests/tcp_rtt.c
where CHECK_FAIL is used.
Also the CHECK macro will print a PASS message on successful map
lookup, which is not expected at this point of the tests.
I think it would be more interesting to leave it as it is to keep a
cohesion between TCP and MPTCP selftests. What do you think?

If there are no objections, I will send a v3 with the other requested
changes and a rebase on the latest bpf-next.

> > +               return -1;
> > +       }
> > +
> > +       if (val.invoked != 1) {
> > +               log_err("%s: unexpected invoked count %d != %d",
> > +                       msg, val.invoked, 1);
> > +               err++;
> > +       }
> > +
> > +       if (val.is_mptcp != is_mptcp) {
> > +               log_err("%s: unexpected bpf_tcp_sock.is_mptcp %d != %d",
> > +                       msg, val.is_mptcp, is_mptcp);
> > +               err++;
> > +       }
> > +
> > +       return err;
> > +}
> > +
> > +static int run_test(int cgroup_fd, int server_fd, bool is_mptcp)
> [...]
>
> > +
> > +       client_fd = is_mptcp ? connect_to_mptcp_fd(server_fd, 0) :
> > +                              connect_to_fd(server_fd, 0);
> > +       if (client_fd < 0) {
> > +               err = -1;
> > +               goto close_client_fd;
>
> This should be "goto close_bpf_object;", and we don't really need the label
> close_client_fd.
>
> > +       }
> > +
> > +       err += is_mptcp ? verify_sk(map_fd, client_fd, "MPTCP subflow socket", 1) :
>
> It doesn't really change the logic, but I guess we only need "err = xxx"?
>
> > +                         verify_sk(map_fd, client_fd, "plain TCP socket", 0);
> > +
> > +close_client_fd:
> > +       close(client_fd);
> > +
> > +close_bpf_object:
> > +       bpf_object__close(obj);
> > +       return err;
> > +}
> > +
Song Liu Sept. 15, 2020, 5:18 p.m. UTC | #3
> On Sep 15, 2020, at 9:35 AM, Nicolas Rybowski <nicolas.rybowski@tessares.net> wrote:
> 
> Hi Song,
> 
> Thanks for the feedback !
> 
> On Mon, Sep 14, 2020 at 8:07 PM Song Liu <song@kernel.org> wrote:
>> 
>> On Fri, Sep 11, 2020 at 8:02 AM Nicolas Rybowski
>> <nicolas.rybowski@tessares.net> wrote:
>>> 
>>> 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 for the moment 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>
>>> Signed-off-by: Nicolas Rybowski <nicolas.rybowski@tessares.net>
>> 
>> Acked-by: Song Liu <songliubraving@fb.com>
>> 
>> With some nitpicks below.
>> 
>>> ---
>>> 
>>> Notes:
>>>    v1 -> v2:
>>>    - new patch: mandatory selftests (Alexei)
>>> 
>> [...]
>>>                     int timeout_ms);
>>> 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..0e65d64868e9
>>> --- /dev/null
>>> +++ b/tools/testing/selftests/bpf/prog_tests/mptcp.c
>>> @@ -0,0 +1,119 @@
>>> +// SPDX-License-Identifier: GPL-2.0
>>> +#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;
>>> +
>>> +       /* Currently there is no easy way to get back the subflow sk from the MPTCP
>>> +        * sk, thus we cannot access here the sk_storage associated to the subflow
>>> +        * sk. Also, there is no sk_storage associated with the MPTCP sk since it
>>> +        * does not trigger sockops events.
>>> +        * We silently pass this situation at the moment.
>>> +        */
>>> +       if (is_mptcp == 1)
>>> +               return 0;
>>> +
>>> +       if (CHECK_FAIL(bpf_map_lookup_elem(map_fd, &cfd, &val) < 0)) {
>>> +               perror("Failed to read socket storage");
>> 
>> Maybe simplify this with CHECK(), which contains a customized error message?
>> Same for some other calls.
>> 
> 
> The whole logic here is strongly inspired from prog_tests/tcp_rtt.c
> where CHECK_FAIL is used.
> Also the CHECK macro will print a PASS message on successful map
> lookup, which is not expected at this point of the tests.
> I think it would be more interesting to leave it as it is to keep a
> cohesion between TCP and MPTCP selftests. What do you think?

I guess CHECK_FAIL makes sense when we don't need the PASS message. 
Let's keep this part as-is then. 

Thanks,
Song
diff mbox series

Patch

diff --git a/tools/testing/selftests/bpf/config b/tools/testing/selftests/bpf/config
index 2118e23ac07a..8377836ea976 100644
--- a/tools/testing/selftests/bpf/config
+++ b/tools/testing/selftests/bpf/config
@@ -39,3 +39,4 @@  CONFIG_BPF_JIT=y
 CONFIG_BPF_LSM=y
 CONFIG_SECURITY=y
 CONFIG_LIRC=y
+CONFIG_MPTCP=y
diff --git a/tools/testing/selftests/bpf/network_helpers.c b/tools/testing/selftests/bpf/network_helpers.c
index 12ee40284da0..85cbb683965c 100644
--- a/tools/testing/selftests/bpf/network_helpers.c
+++ b/tools/testing/selftests/bpf/network_helpers.c
@@ -14,6 +14,10 @@ 
 #include "bpf_util.h"
 #include "network_helpers.h"
 
+#ifndef IPPROTO_MPTCP
+#define IPPROTO_MPTCP 262
+#endif
+
 #define clean_errno() (errno == 0 ? "None" : strerror(errno))
 #define log_err(MSG, ...) ({						\
 			int __save = errno;				\
@@ -66,8 +70,8 @@  static int settimeo(int fd, int timeout_ms)
 
 #define save_errno_close(fd) ({ int __save = errno; close(fd); errno = __save; })
 
-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 len;
@@ -76,7 +80,7 @@  int start_server(int family, int type, const char *addr_str, __u16 port,
 	if (make_sockaddr(family, addr_str, port, &addr, &len))
 		return -1;
 
-	fd = socket(family, type, 0);
+	fd = socket(family, type, protocol);
 	if (fd < 0) {
 		log_err("Failed to create server socket");
 		return -1;
@@ -104,6 +108,19 @@  int start_server(int family, int type, const char *addr_str, __u16 port,
 	return -1;
 }
 
+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 fastopen_connect(int server_fd, const char *data, unsigned int data_len,
 		     int timeout_ms)
 {
@@ -153,7 +170,7 @@  static int connect_fd_to_addr(int fd,
 	return 0;
 }
 
-int connect_to_fd(int server_fd, int timeout_ms)
+static int connect_to_fd_proto(int server_fd, int protocol, int timeout_ms)
 {
 	struct sockaddr_storage addr;
 	struct sockaddr_in *addr_in;
@@ -173,7 +190,7 @@  int connect_to_fd(int server_fd, int timeout_ms)
 	}
 
 	addr_in = (struct sockaddr_in *)&addr;
-	fd = socket(addr_in->sin_family, type, 0);
+	fd = socket(addr_in->sin_family, type, protocol);
 	if (fd < 0) {
 		log_err("Failed to create client socket");
 		return -1;
@@ -192,6 +209,16 @@  int connect_to_fd(int server_fd, int timeout_ms)
 	return -1;
 }
 
+int connect_to_fd(int server_fd, int timeout_ms)
+{
+	return connect_to_fd_proto(server_fd, 0, timeout_ms);
+}
+
+int connect_to_mptcp_fd(int server_fd, int timeout_ms)
+{
+	return connect_to_fd_proto(server_fd, IPPROTO_MPTCP, timeout_ms);
+}
+
 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 7205f8afdba1..336423a789e9 100644
--- a/tools/testing/selftests/bpf/network_helpers.h
+++ b/tools/testing/selftests/bpf/network_helpers.h
@@ -35,7 +35,10 @@  extern struct ipv6_packet pkt_v6;
 
 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 connect_to_fd(int server_fd, int timeout_ms);
+int connect_to_mptcp_fd(int server_fd, int timeout_ms);
 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,
 		     int timeout_ms);
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..0e65d64868e9
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/mptcp.c
@@ -0,0 +1,119 @@ 
+// SPDX-License-Identifier: GPL-2.0
+#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;
+
+	/* Currently there is no easy way to get back the subflow sk from the MPTCP
+	 * sk, thus we cannot access here the sk_storage associated to the subflow
+	 * sk. Also, there is no sk_storage associated with the MPTCP sk since it
+	 * does not trigger sockops events.
+	 * We silently pass this situation at the moment.
+	 */
+	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 != %d",
+			msg, val.invoked, 1);
+		err++;
+	}
+
+	if (val.is_mptcp != is_mptcp) {
+		log_err("%s: unexpected bpf_tcp_sock.is_mptcp %d != %d",
+			msg, val.is_mptcp, 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_object *obj;
+	struct bpf_map *map;
+
+	struct bpf_prog_load_attr attr = {
+		.prog_type = BPF_PROG_TYPE_SOCK_OPS,
+		.file = "./mptcp.o",
+		.expected_attach_type = BPF_CGROUP_SOCK_OPS,
+	};
+
+	err = bpf_prog_load_xattr(&attr, &obj, &prog_fd);
+	if (err) {
+		log_err("Failed to load BPF object");
+		return -1;
+	}
+
+	map = bpf_map__next(NULL, obj);
+	map_fd = bpf_map__fd(map);
+
+	err = bpf_prog_attach(prog_fd, cgroup_fd, BPF_CGROUP_SOCK_OPS, 0);
+	if (err) {
+		log_err("Failed to attach BPF program");
+		goto close_bpf_object;
+	}
+
+	client_fd = is_mptcp ? connect_to_mptcp_fd(server_fd, 0) :
+			       connect_to_fd(server_fd, 0);
+	if (client_fd < 0) {
+		err = -1;
+		goto close_client_fd;
+	}
+
+	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:
+	close(client_fd);
+
+close_bpf_object:
+	bpf_object__close(obj);
+	return err;
+}
+
+void test_mptcp(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);
+}
diff --git a/tools/testing/selftests/bpf/progs/mptcp.c b/tools/testing/selftests/bpf/progs/mptcp.c
new file mode 100644
index 000000000000..be5ee8dac2b3
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/mptcp.c
@@ -0,0 +1,48 @@ 
+// SPDX-License-Identifier: GPL-2.0
+#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;
+
+	sk = ctx->sk;
+	if (!sk)
+		return 1;
+
+	storage = bpf_sk_storage_get(&socket_storage_map, sk, 0,
+				     BPF_SK_STORAGE_GET_F_CREATE);
+	if (!storage)
+		return 1;
+
+	if (op != BPF_SOCK_OPS_TCP_CONNECT_CB)
+		return 1;
+
+	tcp_sk = bpf_tcp_sock(sk);
+	if (!tcp_sk)
+		return 1;
+
+	storage->invoked++;
+	storage->is_mptcp = tcp_sk->is_mptcp;
+
+	return 1;
+}