[PATCH mptcp-next v3 0/6] mptcp: Add userspace PM mode to bypass kernel PM

[PATCH mptcp-next v3 0/6] mptcp: Add userspace PM mode to bypass kernel PM

[Mat Martineau]

One part of supporting userspace path managers is to prevent the
in-kernel PM from acting on userspace-managed MPTCP connections.

These patches:

 * Add a per-MPTCP-socket 'pm_type'. A mix of kernel-managed and
   userspace-managed connections are supported within each namespace.

 * Conditionally decouple incoming ADD_ADDR/RM_ADDR and subflow changes
   from the in-kernel PM. Netlink events are still triggered, and ADD_ADDR
   echo handling is still in kernel code even if path management is
   otherwise handled in userspace.

 * Add a sysctl for setting the per-namespace default for in-kernel vs
   userspace path management of new MPTCP sockets. This is an integer
   value to allow extensibility.

 * Add selftests to confirm that the in-kernel PM is bypassed.

RFC -> v1: Changed sysctl from a bool to an integer, added patch 1
(cleanup) and patch 6 (selftests), fixed ADD_ADDR echo and initial
pm->subflows_allowed settings.

v1 -> v2: Rebased on latest export branch, removed extra kernel-mode
check when receiving ADD_ADDR, and fix !CONFIG_SYSCTL build.

v2 -> v3: Rebased on latest export branch, use helper function for PM
mode, clarify initialization logic for userspace vs. kernel PM,
add a Tested-by tag from v2 review.

Mat Martineau (6):
  mptcp: Remove redundant assignments in path manager init
  mptcp: Add a member to mptcp_pm_data to track kernel vs userspace mode
  mptcp: Bypass kernel PM when userspace PM is enabled
  mptcp: Make kernel path manager check for userspace-managed sockets
  mptcp: Add a per-namespace sysctl to set the default path manager type
  selftests: mptcp: Add tests for userspace PM type

 Documentation/networking/mptcp-sysctl.rst     | 18 +++++
 net/mptcp/ctrl.c                              | 21 ++++++
 net/mptcp/pm.c                                | 50 +++++++++----
 net/mptcp/pm_netlink.c                        | 30 ++++----
 net/mptcp/protocol.h                          | 16 ++++-
 .../testing/selftests/net/mptcp/mptcp_join.sh | 70 ++++++++++++++++++-
 6 files changed, 170 insertions(+), 35 deletions(-)


base-commit: fa9c2885492d7189f9403d92ae3f68f540002093
-- 
2.34.1

[PATCH mptcp-next v3 1/6] mptcp: Remove redundant assignments in path manager init

[Mat Martineau]

A few members of the mptcp_pm_data struct were assigned to hard-coded
values in mptcp_pm_data_reset(), and then immediately changed in
mptcp_pm_nl_data_init().

Instead, flatten all the assignments in to mptcp_pm_data_reset().

v2: Resolve conflicts due to rename of mptcp_pm_data_reset()

Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
---
 net/mptcp/pm.c         | 32 ++++++++++++++++++--------------
 net/mptcp/pm_netlink.c | 12 ------------
 net/mptcp/protocol.h   |  1 -
 3 files changed, 18 insertions(+), 27 deletions(-)

diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
index 761995a34124..4b79b73aee3c 100644
--- a/net/mptcp/pm.c
+++ b/net/mptcp/pm.c
@@ -364,20 +364,24 @@ void mptcp_pm_subflow_chk_stale(const struct mptcp_sock *msk, struct sock *ssk)
 
 void mptcp_pm_data_reset(struct mptcp_sock *msk)
 {
-	msk->pm.add_addr_signaled = 0;
-	msk->pm.add_addr_accepted = 0;
-	msk->pm.local_addr_used = 0;
-	msk->pm.subflows = 0;
-	msk->pm.rm_list_tx.nr = 0;
-	msk->pm.rm_list_rx.nr = 0;
-	WRITE_ONCE(msk->pm.work_pending, false);
-	WRITE_ONCE(msk->pm.addr_signal, 0);
-	WRITE_ONCE(msk->pm.accept_addr, false);
-	WRITE_ONCE(msk->pm.accept_subflow, false);
-	WRITE_ONCE(msk->pm.remote_deny_join_id0, false);
-	msk->pm.status = 0;
-
-	mptcp_pm_nl_data_init(msk);
+	bool subflows_allowed = !!mptcp_pm_get_subflows_max(msk);
+	struct mptcp_pm_data *pm = &msk->pm;
+
+	pm->add_addr_signaled = 0;
+	pm->add_addr_accepted = 0;
+	pm->local_addr_used = 0;
+	pm->subflows = 0;
+	pm->rm_list_tx.nr = 0;
+	pm->rm_list_rx.nr = 0;
+	WRITE_ONCE(pm->work_pending,
+		   (!!mptcp_pm_get_local_addr_max(msk) && subflows_allowed) ||
+		   !!mptcp_pm_get_add_addr_signal_max(msk));
+	WRITE_ONCE(pm->addr_signal, 0);
+	WRITE_ONCE(pm->accept_addr,
+		   !!mptcp_pm_get_add_addr_accept_max(msk) && subflows_allowed);
+	WRITE_ONCE(pm->accept_subflow, subflows_allowed);
+	WRITE_ONCE(pm->remote_deny_join_id0, false);
+	pm->status = 0;
 }
 
 void mptcp_pm_data_init(struct mptcp_sock *msk)
diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index 3186d33b5208..a74eb0444cd2 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -957,18 +957,6 @@ int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct sock_common *skc)
 	return ret;
 }
 
-void mptcp_pm_nl_data_init(struct mptcp_sock *msk)
-{
-	struct mptcp_pm_data *pm = &msk->pm;
-	bool subflows;
-
-	subflows = !!mptcp_pm_get_subflows_max(msk);
-	WRITE_ONCE(pm->work_pending, (!!mptcp_pm_get_local_addr_max(msk) && subflows) ||
-		   !!mptcp_pm_get_add_addr_signal_max(msk));
-	WRITE_ONCE(pm->accept_addr, !!mptcp_pm_get_add_addr_accept_max(msk) && subflows);
-	WRITE_ONCE(pm->accept_subflow, subflows);
-}
-
 #define MPTCP_PM_CMD_GRP_OFFSET       0
 #define MPTCP_PM_EV_GRP_OFFSET        1
 
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 47d24478763c..50175e4cbcb8 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -821,7 +821,6 @@ bool mptcp_pm_rm_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
 int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc);
 
 void __init mptcp_pm_nl_init(void);
-void mptcp_pm_nl_data_init(struct mptcp_sock *msk);
 void mptcp_pm_nl_work(struct mptcp_sock *msk);
 void mptcp_pm_nl_rm_subflow_received(struct mptcp_sock *msk,
 				     const struct mptcp_rm_list *rm_list);
-- 
2.34.1

[PATCH mptcp-next v3 2/6] mptcp: Add a member to mptcp_pm_data to track kernel vs userspace mode

[Mat Martineau]

When adding support for netlink path management commands, the kernel
needs to know whether paths are being controlled by the in-kernel path
manager or a userspace PM.

Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
---
 net/mptcp/pm.c       | 4 ++++
 net/mptcp/protocol.h | 9 +++++++++
 2 files changed, 13 insertions(+)

diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
index 4b79b73aee3c..053afb058440 100644
--- a/net/mptcp/pm.c
+++ b/net/mptcp/pm.c
@@ -373,6 +373,10 @@ void mptcp_pm_data_reset(struct mptcp_sock *msk)
 	pm->subflows = 0;
 	pm->rm_list_tx.nr = 0;
 	pm->rm_list_rx.nr = 0;
+	WRITE_ONCE(pm->pm_type, MPTCP_PM_TYPE_KERNEL);
+	/* pm->work_pending must be only be set to 'true' when
+	 * pm->pm_type is set to MPTCP_PM_TYPE_KERNEL
+	 */
 	WRITE_ONCE(pm->work_pending,
 		   (!!mptcp_pm_get_local_addr_max(msk) && subflows_allowed) ||
 		   !!mptcp_pm_get_add_addr_signal_max(msk));
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 50175e4cbcb8..478abe18b9e9 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -177,6 +177,14 @@ enum mptcp_pm_status {
 	MPTCP_PM_SUBFLOW_ESTABLISHED,
 };
 
+enum mptcp_pm_type {
+	MPTCP_PM_TYPE_KERNEL = 0,
+	MPTCP_PM_TYPE_USERSPACE,
+
+	__MPTCP_PM_TYPE_NR,
+	__MPTCP_PM_TYPE_MAX = __MPTCP_PM_TYPE_NR - 1,
+};
+
 enum mptcp_addr_signal_status {
 	MPTCP_ADD_ADDR_SIGNAL,
 	MPTCP_ADD_ADDR_ECHO,
@@ -199,6 +207,7 @@ struct mptcp_pm_data {
 	u8		add_addr_signaled;
 	u8		add_addr_accepted;
 	u8		local_addr_used;
+	u8		pm_type;
 	u8		subflows;
 	u8		status;
 	struct mptcp_rm_list rm_list_tx;
-- 
2.34.1

[PATCH mptcp-next v3 3/6] mptcp: Bypass kernel PM when userspace PM is enabled

[Mat Martineau]

When a MPTCP connection is managed by a userspace PM, bypass the kernel
PM for incoming advertisements and subflow events. Netlink events are
still sent to userspace.

v2: Remove unneeded check in mptcp_pm_rm_addr_received() (Kishen Maloor)
v3: Add and use helper function for PM mode (Paolo Abeni)

Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
---
 net/mptcp/pm.c       | 2 +-
 net/mptcp/protocol.h | 5 +++++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
index 053afb058440..cff0d9585ab4 100644
--- a/net/mptcp/pm.c
+++ b/net/mptcp/pm.c
@@ -189,7 +189,7 @@ void mptcp_pm_add_addr_received(struct mptcp_sock *msk,
 
 	spin_lock_bh(&pm->lock);
 
-	if (!READ_ONCE(pm->accept_addr)) {
+	if (!READ_ONCE(pm->accept_addr) || mptcp_pm_is_userspace(msk)) {
 		mptcp_pm_announce_addr(msk, addr, true);
 		mptcp_pm_add_addr_send_ack(msk);
 	} else if (mptcp_pm_schedule_work(msk, MPTCP_PM_ADD_ADDR_RECEIVED)) {
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 478abe18b9e9..9e84a46f3d87 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -798,6 +798,11 @@ static inline bool mptcp_pm_should_rm_signal(struct mptcp_sock *msk)
 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_RM_ADDR_SIGNAL);
 }
 
+static inline bool mptcp_pm_is_userspace(struct mptcp_sock *msk)
+{
+	return READ_ONCE(msk->pm.pm_type) != MPTCP_PM_TYPE_KERNEL;
+}
+
 static inline unsigned int mptcp_add_addr_len(int family, bool echo, bool port)
 {
 	u8 len = TCPOLEN_MPTCP_ADD_ADDR_BASE;
-- 
2.34.1

[PATCH mptcp-next v3 4/6] mptcp: Make kernel path manager check for userspace-managed sockets

[Mat Martineau]

Userspace-managed sockets should not have their subflows or
advertisements changed by the kernel path manager.

v3: Use helper function for PM mode (Paolo Abeni)

Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
---
 net/mptcp/pm_netlink.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index a74eb0444cd2..6df683459478 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -1122,7 +1122,8 @@ static int mptcp_nl_add_subflow_or_signal_addr(struct net *net)
 	while ((msk = mptcp_token_iter_next(net, &s_slot, &s_num)) != NULL) {
 		struct sock *sk = (struct sock *)msk;
 
-		if (!READ_ONCE(msk->fully_established))
+		if (!READ_ONCE(msk->fully_established) ||
+		    mptcp_pm_is_userspace(msk))
 			goto next;
 
 		lock_sock(sk);
@@ -1260,6 +1261,9 @@ static int mptcp_nl_remove_subflow_and_signal_addr(struct net *net,
 		struct sock *sk = (struct sock *)msk;
 		bool remove_subflow;
 
+		if (mptcp_pm_is_userspace(msk))
+			goto next;
+
 		if (list_empty(&msk->conn_list)) {
 			mptcp_pm_remove_anno_addr(msk, addr, false);
 			goto next;
@@ -1301,7 +1305,7 @@ static int mptcp_nl_remove_id_zero_address(struct net *net,
 		struct sock *sk = (struct sock *)msk;
 		struct mptcp_addr_info msk_local;
 
-		if (list_empty(&msk->conn_list))
+		if (list_empty(&msk->conn_list) || mptcp_pm_is_userspace(msk))
 			goto next;
 
 		local_address((struct sock_common *)msk, &msk_local);
@@ -1410,9 +1414,11 @@ static void mptcp_nl_remove_addrs_list(struct net *net,
 	while ((msk = mptcp_token_iter_next(net, &s_slot, &s_num)) != NULL) {
 		struct sock *sk = (struct sock *)msk;
 
-		lock_sock(sk);
-		mptcp_pm_remove_addrs_and_subflows(msk, rm_list);
-		release_sock(sk);
+		if (!mptcp_pm_is_userspace(msk)) {
+			lock_sock(sk);
+			mptcp_pm_remove_addrs_and_subflows(msk, rm_list);
+			release_sock(sk);
+		}
 
 		sock_put(sk);
 		cond_resched();
@@ -1674,7 +1680,7 @@ static int mptcp_nl_addr_backup(struct net *net,
 	while ((msk = mptcp_token_iter_next(net, &s_slot, &s_num)) != NULL) {
 		struct sock *sk = (struct sock *)msk;
 
-		if (list_empty(&msk->conn_list))
+		if (list_empty(&msk->conn_list) || mptcp_pm_is_userspace(msk))
 			goto next;
 
 		lock_sock(sk);
-- 
2.34.1

[PATCH mptcp-next v3 5/6] mptcp: Add a per-namespace sysctl to set the default path manager type

[Mat Martineau]

The new net.mptcp.pm_type sysctl determines which path manager will be
used by each newly-created MPTCP socket.

v2: Handle builds without CONFIG_SYSCTL
v3: Clarify logic for type-specific PM init (Geliang Tang and Paolo Abeni)

Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
---
 Documentation/networking/mptcp-sysctl.rst | 18 ++++++++++++
 net/mptcp/ctrl.c                          | 21 ++++++++++++++
 net/mptcp/pm.c                            | 34 +++++++++++++++--------
 net/mptcp/protocol.h                      |  1 +
 4 files changed, 63 insertions(+), 11 deletions(-)

diff --git a/Documentation/networking/mptcp-sysctl.rst b/Documentation/networking/mptcp-sysctl.rst
index b0d4da71e68e..e263dfcc4b40 100644
--- a/Documentation/networking/mptcp-sysctl.rst
+++ b/Documentation/networking/mptcp-sysctl.rst
@@ -46,6 +46,24 @@ allow_join_initial_addr_port - BOOLEAN
 
 	Default: 1
 
+pm_type - INTEGER
+
+	Set the default path manager type to use for each new MPTCP
+	socket. In-kernel path management will control subflow
+	connections and address advertisements according to
+	per-namespace values configured over the MPTCP netlink
+	API. Userspace path management puts per-MPTCP-connection subflow
+	connection decisions and address advertisements under control of
+	a privileged userspace program, at the cost of more netlink
+	traffic to propagate all of the related events and commands.
+
+	This is a per-namespace sysctl.
+
+	* 0 - In-kernel path manager
+	* 1 - Userspace path manager
+
+	Default: 0
+
 stale_loss_cnt - INTEGER
 	The number of MPTCP-level retransmission intervals with no traffic and
 	pending outstanding data on a given subflow required to declare it stale.
diff --git a/net/mptcp/ctrl.c b/net/mptcp/ctrl.c
index 8b235468c88f..ae20b7d92e28 100644
--- a/net/mptcp/ctrl.c
+++ b/net/mptcp/ctrl.c
@@ -16,6 +16,11 @@
 #define MPTCP_SYSCTL_PATH "net/mptcp"
 
 static int mptcp_pernet_id;
+
+#ifdef CONFIG_SYSCTL
+static int mptcp_pm_type_max = __MPTCP_PM_TYPE_MAX;
+#endif
+
 struct mptcp_pernet {
 #ifdef CONFIG_SYSCTL
 	struct ctl_table_header *ctl_table_hdr;
@@ -26,6 +31,7 @@ struct mptcp_pernet {
 	u8 mptcp_enabled;
 	u8 checksum_enabled;
 	u8 allow_join_initial_addr_port;
+	u8 pm_type;
 };
 
 static struct mptcp_pernet *mptcp_get_pernet(const struct net *net)
@@ -58,6 +64,11 @@ unsigned int mptcp_stale_loss_cnt(const struct net *net)
 	return mptcp_get_pernet(net)->stale_loss_cnt;
 }
 
+int mptcp_get_pm_type(const struct net *net)
+{
+	return mptcp_get_pernet(net)->pm_type;
+}
+
 static void mptcp_pernet_set_defaults(struct mptcp_pernet *pernet)
 {
 	pernet->mptcp_enabled = 1;
@@ -65,6 +76,7 @@ static void mptcp_pernet_set_defaults(struct mptcp_pernet *pernet)
 	pernet->checksum_enabled = 0;
 	pernet->allow_join_initial_addr_port = 1;
 	pernet->stale_loss_cnt = 4;
+	pernet->pm_type = MPTCP_PM_TYPE_KERNEL;
 }
 
 #ifdef CONFIG_SYSCTL
@@ -108,6 +120,14 @@ static struct ctl_table mptcp_sysctl_table[] = {
 		.mode = 0644,
 		.proc_handler = proc_douintvec_minmax,
 	},
+	{
+		.procname = "pm_type",
+		.maxlen = sizeof(u8),
+		.mode = 0644,
+		.proc_handler = proc_dou8vec_minmax,
+		.extra1       = SYSCTL_ZERO,
+		.extra2       = &mptcp_pm_type_max
+	},
 	{}
 };
 
@@ -128,6 +148,7 @@ static int mptcp_pernet_new_table(struct net *net, struct mptcp_pernet *pernet)
 	table[2].data = &pernet->checksum_enabled;
 	table[3].data = &pernet->allow_join_initial_addr_port;
 	table[4].data = &pernet->stale_loss_cnt;
+	table[5].data = &pernet->pm_type;
 
 	hdr = register_net_sysctl(net, MPTCP_SYSCTL_PATH, table);
 	if (!hdr)
diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
index cff0d9585ab4..71b843c0ac42 100644
--- a/net/mptcp/pm.c
+++ b/net/mptcp/pm.c
@@ -364,7 +364,7 @@ void mptcp_pm_subflow_chk_stale(const struct mptcp_sock *msk, struct sock *ssk)
 
 void mptcp_pm_data_reset(struct mptcp_sock *msk)
 {
-	bool subflows_allowed = !!mptcp_pm_get_subflows_max(msk);
+	u8 pm_type = mptcp_get_pm_type(sock_net((struct sock *)msk));
 	struct mptcp_pm_data *pm = &msk->pm;
 
 	pm->add_addr_signaled = 0;
@@ -373,17 +373,29 @@ void mptcp_pm_data_reset(struct mptcp_sock *msk)
 	pm->subflows = 0;
 	pm->rm_list_tx.nr = 0;
 	pm->rm_list_rx.nr = 0;
-	WRITE_ONCE(pm->pm_type, MPTCP_PM_TYPE_KERNEL);
-	/* pm->work_pending must be only be set to 'true' when
-	 * pm->pm_type is set to MPTCP_PM_TYPE_KERNEL
-	 */
-	WRITE_ONCE(pm->work_pending,
-		   (!!mptcp_pm_get_local_addr_max(msk) && subflows_allowed) ||
-		   !!mptcp_pm_get_add_addr_signal_max(msk));
+	WRITE_ONCE(pm->pm_type, pm_type);
+
+	if (pm_type == MPTCP_PM_TYPE_KERNEL) {
+		bool subflows_allowed = !!mptcp_pm_get_subflows_max(msk);
+
+		/* pm->work_pending must be only be set to 'true' when
+		 * pm->pm_type is set to MPTCP_PM_TYPE_KERNEL
+		 */
+		WRITE_ONCE(pm->work_pending,
+			   (!!mptcp_pm_get_local_addr_max(msk) &&
+			    subflows_allowed) ||
+			   !!mptcp_pm_get_add_addr_signal_max(msk));
+		WRITE_ONCE(pm->accept_addr,
+			   !!mptcp_pm_get_add_addr_accept_max(msk) &&
+			   subflows_allowed);
+		WRITE_ONCE(pm->accept_subflow, subflows_allowed);
+	} else {
+		WRITE_ONCE(pm->work_pending, 0);
+		WRITE_ONCE(pm->accept_addr, 0);
+		WRITE_ONCE(pm->accept_subflow, 0);
+	}
+
 	WRITE_ONCE(pm->addr_signal, 0);
-	WRITE_ONCE(pm->accept_addr,
-		   !!mptcp_pm_get_add_addr_accept_max(msk) && subflows_allowed);
-	WRITE_ONCE(pm->accept_subflow, subflows_allowed);
 	WRITE_ONCE(pm->remote_deny_join_id0, false);
 	pm->status = 0;
 }
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 9e84a46f3d87..9c6996254d86 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -579,6 +579,7 @@ unsigned int mptcp_get_add_addr_timeout(const struct net *net);
 int mptcp_is_checksum_enabled(const struct net *net);
 int mptcp_allow_join_id0(const struct net *net);
 unsigned int mptcp_stale_loss_cnt(const struct net *net);
+int mptcp_get_pm_type(const struct net *net);
 void mptcp_subflow_fully_established(struct mptcp_subflow_context *subflow,
 				     struct mptcp_options_received *mp_opt);
 bool __mptcp_retransmit_pending_data(struct sock *sk);
-- 
2.34.1

[PATCH mptcp-next v3 6/6] selftests: mptcp: Add tests for userspace PM type

[Mat Martineau]

These tests ensure that the in-kernel path manager is bypassed when
the userspace path manager is configured. Kernel code is still
responsible for ADD_ADDR echo, so also make sure that's working.

Tested-by: Geliang Tang <geliang.tang@suse.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
---
 .../testing/selftests/net/mptcp/mptcp_join.sh | 70 ++++++++++++++++++-
 1 file changed, 69 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/net/mptcp/mptcp_join.sh b/tools/testing/selftests/net/mptcp/mptcp_join.sh
index 2684ef9c0d42..7df9ddb307a8 100755
--- a/tools/testing/selftests/net/mptcp/mptcp_join.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_join.sh
@@ -50,6 +50,7 @@ init()
 		ip netns add $netns || exit $ksft_skip
 		ip -net $netns link set lo up
 		ip netns exec $netns sysctl -q net.mptcp.enabled=1
+		ip netns exec $netns sysctl -q net.mptcp.pm_type=0
 		ip netns exec $netns sysctl -q net.ipv4.conf.all.rp_filter=0
 		ip netns exec $netns sysctl -q net.ipv4.conf.default.rp_filter=0
 		if [ $checksum -eq 1 ]; then
@@ -1837,6 +1838,68 @@ fullmesh_tests()
 	chk_add_nr 1 1
 }
 
+userspace_tests()
+{
+	# userspace pm type prevents add_addr
+	reset
+	ip netns exec $ns1 sysctl -q net.mptcp.pm_type=1
+	ip netns exec $ns1 ./pm_nl_ctl limits 0 2
+	ip netns exec $ns2 ./pm_nl_ctl limits 0 2
+	ip netns exec $ns1 ./pm_nl_ctl add 10.0.2.1 flags signal
+	run_tests $ns1 $ns2 10.0.1.1
+	chk_join_nr "userspace pm type prevents add_addr" 0 0 0
+	chk_add_nr 0 0
+
+	# userspace pm type echoes add_addr
+	reset
+	ip netns exec $ns2 sysctl -q net.mptcp.pm_type=1
+	ip netns exec $ns1 ./pm_nl_ctl limits 0 2
+	ip netns exec $ns2 ./pm_nl_ctl limits 0 2
+	ip netns exec $ns1 ./pm_nl_ctl add 10.0.2.1 flags signal
+	run_tests $ns1 $ns2 10.0.1.1
+	chk_join_nr "userspace pm type echoes add_addr" 0 0 0
+	chk_add_nr 1 1
+
+	# userspace pm type rejects join
+	reset
+	ip netns exec $ns1 sysctl -q net.mptcp.pm_type=1
+	ip netns exec $ns1 ./pm_nl_ctl limits 1 1
+	ip netns exec $ns2 ./pm_nl_ctl limits 1 1
+	ip netns exec $ns2 ./pm_nl_ctl add 10.0.3.2 flags subflow
+	run_tests $ns1 $ns2 10.0.1.1
+	chk_join_nr "userspace pm type rejects join" 1 1 0
+
+	# userspace pm type does not send join
+	reset
+	ip netns exec $ns2 sysctl -q net.mptcp.pm_type=1
+	ip netns exec $ns1 ./pm_nl_ctl limits 1 1
+	ip netns exec $ns2 ./pm_nl_ctl limits 1 1
+	ip netns exec $ns2 ./pm_nl_ctl add 10.0.3.2 flags subflow
+	run_tests $ns1 $ns2 10.0.1.1
+	chk_join_nr "userspace pm type does not send join" 0 0 0
+
+	# userspace pm type prevents mp_prio
+	reset
+	ip netns exec $ns1 sysctl -q net.mptcp.pm_type=1
+	ip netns exec $ns1 ./pm_nl_ctl limits 1 1
+	ip netns exec $ns2 ./pm_nl_ctl limits 1 1
+	ip netns exec $ns2 ./pm_nl_ctl add 10.0.3.2 flags subflow
+	run_tests $ns1 $ns2 10.0.1.1 0 0 0 slow backup
+	chk_join_nr "userspace pm type prevents mp_prio" 1 1 0
+	chk_prio_nr 0 0
+
+	# userspace pm type prevents rm_addr
+	reset
+	ip netns exec $ns1 sysctl -q net.mptcp.pm_type=1
+	ip netns exec $ns2 sysctl -q net.mptcp.pm_type=1
+	ip netns exec $ns1 ./pm_nl_ctl limits 0 1
+	ip netns exec $ns2 ./pm_nl_ctl limits 0 1
+	ip netns exec $ns2 ./pm_nl_ctl add 10.0.3.2 flags subflow
+	run_tests $ns1 $ns2 10.0.1.1 0 0 -1 slow
+	chk_join_nr "userspace pm type prevents rm_addr" 0 0 0
+	chk_rm_nr 0 0
+}
+
 all_tests()
 {
 	subflows_tests
@@ -1853,6 +1916,7 @@ all_tests()
 	checksum_tests
 	deny_join_id0_tests
 	fullmesh_tests
+	userspace_tests
 }
 
 usage()
@@ -1872,6 +1936,7 @@ usage()
 	echo "  -S checksum_tests"
 	echo "  -d deny_join_id0_tests"
 	echo "  -m fullmesh_tests"
+	echo "  -u userspace_tests"
 	echo "  -c capture pcap files"
 	echo "  -C enable data checksum"
 	echo "  -h help"
@@ -1907,7 +1972,7 @@ if [ $do_all_tests -eq 1 ]; then
 	exit $ret
 fi
 
-while getopts 'fsltra64bpkdmchCS' opt; do
+while getopts 'fsltra64bpkdmuchCS' opt; do
 	case $opt in
 		f)
 			subflows_tests
@@ -1951,6 +2016,9 @@ while getopts 'fsltra64bpkdmchCS' opt; do
 		m)
 			fullmesh_tests
 			;;
+		u)
+			userspace_tests
+			;;
 		c)
 			;;
 		C)
-- 
2.34.1