Series comparison

From: Geliang Tang <tanggeliang@kylinos.cn>

get_addr() and dump_addr() interfaces of BPF userspace pm are dropped
as Matt suggested.

Based-on: <cover.1736924314.git.tanggeliang@kylinos.cn>

In order to implement BPF userspace path manager, it is necessary to
unify the interfaces of the path manager. This set contains some
cleanups and refactoring to unify the interfaces in kernel space.
Finally, define a struct mptcp_pm_ops for a userspace path manager
like this:

struct mptcp_pm_ops {
	int (*address_announce)(struct mptcp_sock *msk,
				struct mptcp_pm_addr_entry *local);
	int (*address_remove)(struct mptcp_sock *msk, u8 id);
	int (*subflow_create)(struct mptcp_sock *msk,
			      struct mptcp_pm_addr_entry *local,
			      struct mptcp_addr_info *remote);
	int (*subflow_destroy)(struct mptcp_sock *msk,
			       struct mptcp_pm_addr_entry *local,
			       struct mptcp_addr_info *remote);
	int (*get_local_id)(struct mptcp_sock *msk,
			    struct mptcp_pm_addr_entry *local);
	u8 (*get_flags)(struct mptcp_sock *msk,
			struct mptcp_addr_info *skc);
	int (*set_flags)(struct mptcp_sock *msk,
			 struct mptcp_pm_addr_entry *local,
			 struct mptcp_addr_info *remote);

u8			type;
	struct module		*owner;
	struct list_head	list;

void (*init)(struct mptcp_sock *msk);
	void (*release)(struct mptcp_sock *msk);
} ____cacheline_aligned_in_smp;

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/74

Geliang Tang (3):
  mptcp: define struct mptcp_pm_ops
  mptcp: register default userspace pm
  mptcp: init and release mptcp_pm_ops

-- 
2.43.0

From: Geliang Tang <tanggeliang@kylinos.cn>

In order to allow users to develop their own BPF-based path manager,
this patch defines a struct ops "mptcp_pm_ops" for a userspace path
manager, which contains a set of interfaces.

Add a set of functions to register, unregister, find and validate a
given struct ops.

Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
---
 include/net/mptcp.h      | 27 +++++++++++++++++++
 net/mptcp/pm_userspace.c | 57 ++++++++++++++++++++++++++++++++++++++++
 net/mptcp/protocol.h     |  5 ++++
 3 files changed, 89 insertions(+)

diff --git a/include/net/mptcp.h b/include/net/mptcp.h
index XXXXXXX..XXXXXXX 100644
--- a/include/net/mptcp.h
+++ b/include/net/mptcp.h
@@ -XXX,XX +XXX,XX @@
 
 struct mptcp_info;
 struct mptcp_sock;
+struct mptcp_pm_addr_entry;
 struct seq_file;
 
 /* MPTCP sk_buff extension data */
@@ -XXX,XX +XXX,XX @@ struct mptcp_sched_ops {
 	void (*release)(struct mptcp_sock *msk);
 } ____cacheline_aligned_in_smp;
 
+struct mptcp_pm_ops {
+	int (*address_announce)(struct mptcp_sock *msk,
+				struct mptcp_pm_addr_entry *local);
+	int (*address_remove)(struct mptcp_sock *msk, u8 id);
+	int (*subflow_create)(struct mptcp_sock *msk,
+			      struct mptcp_pm_addr_entry *local,
+			      struct mptcp_addr_info *remote);
+	int (*subflow_destroy)(struct mptcp_sock *msk,
+			       struct mptcp_pm_addr_entry *local,
+			       struct mptcp_addr_info *remote);
+	int (*get_local_id)(struct mptcp_sock *msk,
+			    struct mptcp_pm_addr_entry *local);
+	u8 (*get_flags)(struct mptcp_sock *msk,
+			struct mptcp_addr_info *skc);
+	int (*set_flags)(struct mptcp_sock *msk,
+			 struct mptcp_pm_addr_entry *local,
+			 struct mptcp_addr_info *remote);
+
+	u8			type;
+	struct module		*owner;
+	struct list_head	list;
+
+	void (*init)(struct mptcp_sock *msk);
+	void (*release)(struct mptcp_sock *msk);
+} ____cacheline_aligned_in_smp;
+
 #ifdef CONFIG_MPTCP
 void mptcp_init(void);
 
diff --git a/net/mptcp/pm_userspace.c b/net/mptcp/pm_userspace.c
index XXXXXXX..XXXXXXX 100644
--- a/net/mptcp/pm_userspace.c
+++ b/net/mptcp/pm_userspace.c
@@ -XXX,XX +XXX,XX @@
  * Copyright (c) 2022, Intel Corporation.
  */
 
+#include <linux/rculist.h>
+#include <linux/spinlock.h>
 #include "protocol.h"
 #include "mib.h"
 #include "mptcp_pm_gen.h"
@@ -XXX,XX +XXX,XX @@
 	list_for_each_entry(__entry,						\
 			    &((__msk)->pm.userspace_pm_local_addr_list), list)
 
+static DEFINE_SPINLOCK(mptcp_pm_list_lock);
+static LIST_HEAD(mptcp_pm_list);
+
 void mptcp_free_local_addr_list(struct mptcp_sock *msk)
 {
 	struct mptcp_pm_addr_entry *entry, *tmp;
@@ -XXX,XX +XXX,XX @@ int mptcp_userspace_pm_get_addr(u8 id, struct mptcp_pm_addr_entry *addr,
 	sock_put(sk);
 	return ret;
 }
+
+/* Must be called with rcu read lock held */
+struct mptcp_pm_ops *mptcp_pm_find(enum mptcp_pm_type type)
+{
+	struct mptcp_pm_ops *pm;
+
+	list_for_each_entry_rcu(pm, &mptcp_pm_list, list) {
+		if (pm->type == type)
+			return pm;
+	}
+
+	return NULL;
+}
+
+int mptcp_validate_path_manager(struct mptcp_pm_ops *pm)
+{
+	if (!pm->address_announce && !pm->address_remove &&
+	    !pm->subflow_create && !pm->subflow_destroy &&
+	    !pm->get_local_id && !pm->get_flags && !pm->set_flags) {
+		pr_err("%u does not implement required ops\n", pm->type);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+int mptcp_register_path_manager(struct mptcp_pm_ops *pm)
+{
+	int ret;
+
+	ret = mptcp_validate_path_manager(pm);
+	if (ret)
+		return ret;
+
+	spin_lock(&mptcp_pm_list_lock);
+	if (mptcp_pm_find(pm->type)) {
+		spin_unlock(&mptcp_pm_list_lock);
+		return -EEXIST;
+	}
+	list_add_tail_rcu(&pm->list, &mptcp_pm_list);
+	spin_unlock(&mptcp_pm_list_lock);
+
+	pr_debug("userspace_pm type %u registered\n", pm->type);
+	return 0;
+}
+
+void mptcp_unregister_path_manager(struct mptcp_pm_ops *pm)
+{
+	spin_lock(&mptcp_pm_list_lock);
+	list_del_rcu(&pm->list);
+	spin_unlock(&mptcp_pm_list_lock);
+}
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index XXXXXXX..XXXXXXX 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -XXX,XX +XXX,XX @@ int mptcp_pm_remove_addr(struct mptcp_sock *msk, const struct mptcp_rm_list *rm_
 void mptcp_pm_remove_addr_entry(struct mptcp_sock *msk,
 				struct mptcp_pm_addr_entry *entry);
 
+struct mptcp_pm_ops *mptcp_pm_find(enum mptcp_pm_type type);
+int mptcp_validate_path_manager(struct mptcp_pm_ops *pm);
+int mptcp_register_path_manager(struct mptcp_pm_ops *pm);
+void mptcp_unregister_path_manager(struct mptcp_pm_ops *pm);
+
 void mptcp_free_local_addr_list(struct mptcp_sock *msk);
 
 void mptcp_event(enum mptcp_event_type type, const struct mptcp_sock *msk,
-- 
2.43.0

From: Geliang Tang <tanggeliang@kylinos.cn>

This patch defines the original userspace pm as the default path manager,
named mptcp_userspace_pm, and register it in mptcp_pm_data_init().

Extract address_announce() interface of the userspace PM from the handler
of netlink commond MPTCP_PM_CMD_ANNOUNCE mptcp_pm_nl_announce_doit(), only
leave the code for obtaining msk through "info" and parsing address entry
in the handler.

Extract address_remove() interface of the userspace PM from the handler
of netlink commond MPTCP_PM_CMD_REMOVE mptcp_pm_nl_remove_doit(), only
leave the code for parsing address id and obtaining msk through "info"
in the handler.

Extract subflow_create() interface of the userspace PM from the handler of
netlink commond MPTCP_PM_CMD_SUBFLOW_CREATE

mptcp_pm_nl_subflow_create_doit(),

only leave the code for obtaining msk through "info", parsing local address
entry and parsing remote address info in the handler.

Extract subflow_destroy() interface of the userspace PM from the handler of
netlink commond MPTCP_PM_CMD_SUBFLOW_DESTROY

mptcp_pm_nl_subflow_destroy_doit(),

only leave the code for obtaining msk through "info", parsing local address
entry and parsing remote address info in the handler.

Extract set_flags() interface of the userspace PM from function
mptcp_userspace_pm_set_flags(), only leave the code for obtaining
msk through "info" in this function.

All fives interfaces are invoked under holding the msk socket lock.

Other interfaces get_local_id() and get_flags() are only defined as
wrappers.

Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
---
 net/mptcp/pm.c           |   1 +
 net/mptcp/pm_userspace.c | 261 ++++++++++++++++++++++++---------------
 net/mptcp/protocol.h     |   1 +
 3 files changed, 165 insertions(+), 98 deletions(-)

diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
index XXXXXXX..XXXXXXX 100644
--- a/net/mptcp/pm.c
+++ b/net/mptcp/pm.c
@@ -XXX,XX +XXX,XX @@ void mptcp_pm_data_init(struct mptcp_sock *msk)
 void __init mptcp_pm_init(void)
 {
 	mptcp_pm_nl_init();
+	mptcp_userspace_pm_init();
 }
diff --git a/net/mptcp/pm_userspace.c b/net/mptcp/pm_userspace.c
index XXXXXXX..XXXXXXX 100644
--- a/net/mptcp/pm_userspace.c
+++ b/net/mptcp/pm_userspace.c
@@ -XXX,XX +XXX,XX @@ mptcp_userspace_pm_lookup_addr_by_id(struct mptcp_sock *msk, unsigned int id)
 	return NULL;
 }
 
-int mptcp_userspace_pm_get_local_id(struct mptcp_sock *msk,
-				    struct mptcp_pm_addr_entry *local)
+static int userspace_pm_get_local_id(struct mptcp_sock *msk,
+				     struct mptcp_pm_addr_entry *local)
 {
 	__be16 msk_sport =  ((struct inet_sock *)
 			     inet_sk((struct sock *)msk))->inet_sport;
@@ -XXX,XX +XXX,XX @@ int mptcp_userspace_pm_get_local_id(struct mptcp_sock *msk,
 	return mptcp_userspace_pm_append_new_local_addr(msk, local, true);
 }
 
-u8 mptcp_userspace_pm_get_flags(struct mptcp_sock *msk,
-				struct mptcp_addr_info *skc)
+int mptcp_userspace_pm_get_local_id(struct mptcp_sock *msk,
+				    struct mptcp_pm_addr_entry *local)
+{
+	return userspace_pm_get_local_id(msk, local);
+}
+
+static u8 userspace_pm_get_flags(struct mptcp_sock *msk,
+				 struct mptcp_addr_info *skc)
 {
 	struct mptcp_pm_addr_entry *entry;
 	u8 flags;
@@ -XXX,XX +XXX,XX @@ u8 mptcp_userspace_pm_get_flags(struct mptcp_sock *msk,
 	return flags;
 }
 
+u8 mptcp_userspace_pm_get_flags(struct mptcp_sock *msk,
+				struct mptcp_addr_info *skc)
+{
+	return userspace_pm_get_flags(msk, skc);
+}
+
 static struct mptcp_sock *mptcp_userspace_pm_get_sock(const struct genl_info *info)
 {
 	struct mptcp_sock *msk;
@@ -XXX,XX +XXX,XX @@ static struct mptcp_sock *mptcp_userspace_pm_get_sock(const struct genl_info *in
 	return msk;
 }
 
+static int userspace_pm_address_announce(struct mptcp_sock *msk,
+					 struct mptcp_pm_addr_entry *local)
+{
+	int err;
+
+	err = mptcp_userspace_pm_append_new_local_addr(msk, local, false);
+	if (err < 0)
+		return err;
+
+	spin_lock_bh(&msk->pm.lock);
+
+	if (mptcp_pm_alloc_anno_list(msk, &local->addr)) {
+		msk->pm.add_addr_signaled++;
+		mptcp_pm_announce_addr(msk, &local->addr, false);
+		mptcp_pm_nl_addr_send_ack(msk);
+	}
+
+	spin_unlock_bh(&msk->pm.lock);
+
+	return 0;
+}
+
 int mptcp_pm_nl_announce_doit(struct sk_buff *skb, struct genl_info *info)
 {
 	struct mptcp_pm_addr_entry addr_val;
@@ -XXX,XX +XXX,XX @@ int mptcp_pm_nl_announce_doit(struct sk_buff *skb, struct genl_info *info)
 		goto announce_err;
 	}
 
-	err = mptcp_userspace_pm_append_new_local_addr(msk, &addr_val, false);
-	if (err < 0) {
-		NL_SET_ERR_MSG_ATTR(info->extack, addr,
-				    "did not match address and id");
-		goto announce_err;
-	}
-
 	lock_sock(sk);
-	spin_lock_bh(&msk->pm.lock);
-
-	if (mptcp_pm_alloc_anno_list(msk, &addr_val.addr)) {
-		msk->pm.add_addr_signaled++;
-		mptcp_pm_announce_addr(msk, &addr_val.addr, false);
-		mptcp_pm_nl_addr_send_ack(msk);
-	}
-
-	spin_unlock_bh(&msk->pm.lock);
+	err = userspace_pm_address_announce(msk, &addr_val);
 	release_sock(sk);
+	if (err)
+		NL_SET_ERR_MSG_ATTR(info->extack, addr,
+				    "did not match address and id");
 
-	err = 0;
  announce_err:
 	sock_put(sk);
 	return err;
@@ -XXX,XX +XXX,XX @@ void mptcp_pm_remove_addr_entry(struct mptcp_sock *msk,
 	spin_unlock_bh(&msk->pm.lock);
 }
 
+static int userspace_pm_address_remove(struct mptcp_sock *msk, u8 id)
+{
+	struct mptcp_pm_addr_entry *entry;
+
+	if (id == 0)
+		return mptcp_userspace_pm_remove_id_zero_address(msk);
+
+	spin_lock_bh(&msk->pm.lock);
+	entry = mptcp_userspace_pm_lookup_addr_by_id(msk, id);
+	if (!entry) {
+		spin_unlock_bh(&msk->pm.lock);
+		return -EINVAL;
+	}
+
+	list_del_rcu(&entry->list);
+	spin_unlock_bh(&msk->pm.lock);
+
+	mptcp_pm_remove_addr_entry(msk, entry);
+
+	sock_kfree_s((struct sock *)msk, entry, sizeof(*entry));
+
+	return 0;
+}
+
 int mptcp_pm_nl_remove_doit(struct sk_buff *skb, struct genl_info *info)
 {
-	struct mptcp_pm_addr_entry *match;
 	struct mptcp_sock *msk;
 	struct nlattr *id;
 	int err = -EINVAL;
@@ -XXX,XX +XXX,XX @@ int mptcp_pm_nl_remove_doit(struct sk_buff *skb, struct genl_info *info)
 	sk = (struct sock *)msk;
 
 	lock_sock(sk);
-
-	if (id_val == 0) {
-		err = mptcp_userspace_pm_remove_id_zero_address(msk);
-		release_sock(sk);
-		goto out;
-	}
-
-	spin_lock_bh(&msk->pm.lock);
-	match = mptcp_userspace_pm_lookup_addr_by_id(msk, id_val);
-	if (!match) {
-		spin_unlock_bh(&msk->pm.lock);
-		release_sock(sk);
-		goto out;
-	}
-
-	list_del_rcu(&match->list);
-	spin_unlock_bh(&msk->pm.lock);
-
-	mptcp_pm_remove_addr_entry(msk, match);
-
+	err = userspace_pm_address_remove(msk, id_val);
 	release_sock(sk);
-
-	sock_kfree_s(sk, match, sizeof(*match));
-
-	err = 0;
-out:
 	if (err)
 		NL_SET_ERR_MSG_ATTR_FMT(info->extack, id,
 					"address with id %u not found",
@@ -XXX,XX +XXX,XX @@ int mptcp_pm_nl_remove_doit(struct sk_buff *skb, struct genl_info *info)
 	return err;
 }
 
+static int userspace_pm_subflow_create(struct mptcp_sock *msk,
+				       struct mptcp_pm_addr_entry *entry,
+				       struct mptcp_addr_info *remote)
+{
+	struct sock *sk = (struct sock *)msk;
+	struct mptcp_pm_local local;
+	int err;
+
+	err = mptcp_userspace_pm_append_new_local_addr(msk, entry, false);
+	if (err < 0)
+		return err;
+
+	local.addr = entry->addr;
+	local.flags = entry->flags;
+	local.ifindex = entry->ifindex;
+
+	err = __mptcp_subflow_connect(sk, &local, remote);
+	spin_lock_bh(&msk->pm.lock);
+	if (err)
+		mptcp_userspace_pm_delete_local_addr(msk, entry);
+	else
+		msk->pm.subflows++;
+	spin_unlock_bh(&msk->pm.lock);
+
+	return 0;
+}
+
 int mptcp_pm_nl_subflow_create_doit(struct sk_buff *skb, struct genl_info *info)
 {
 	struct mptcp_pm_addr_entry entry = { 0 };
 	struct mptcp_addr_info addr_r;
 	struct nlattr *raddr, *laddr;
-	struct mptcp_pm_local local;
 	struct mptcp_sock *msk;
 	int err = -EINVAL;
 	struct sock *sk;
@@ -XXX,XX +XXX,XX @@ int mptcp_pm_nl_subflow_create_doit(struct sk_buff *skb, struct genl_info *info)
 		goto create_err;
 	}
 
-	err = mptcp_userspace_pm_append_new_local_addr(msk, &entry, false);
-	if (err < 0) {
-		NL_SET_ERR_MSG_ATTR(info->extack, laddr,
-				    "did not match address and id");
-		goto create_err;
-	}
-
-	local.addr = entry.addr;
-	local.flags = entry.flags;
-	local.ifindex = entry.ifindex;
-
 	lock_sock(sk);
-	err = __mptcp_subflow_connect(sk, &local, &addr_r);
+	err = userspace_pm_subflow_create(msk, &entry, &addr_r);
 	release_sock(sk);
 
 	if (err)
 		GENL_SET_ERR_MSG_FMT(info, "connect error: %d", err);
 
-	spin_lock_bh(&msk->pm.lock);
-	if (err)
-		mptcp_userspace_pm_delete_local_addr(msk, &entry);
-	else
-		msk->pm.subflows++;
-	spin_unlock_bh(&msk->pm.lock);
-
  create_err:
 	sock_put(sk);
 	return err;
@@ -XXX,XX +XXX,XX @@ static struct sock *mptcp_nl_find_ssk(struct mptcp_sock *msk,
 	return NULL;
 }
 
+static int userspace_pm_subflow_destroy(struct mptcp_sock *msk,
+					struct mptcp_pm_addr_entry *local,
+					struct mptcp_addr_info *remote)
+{
+	struct sock *ssk, *sk = (struct sock *)msk;
+
+	ssk = mptcp_nl_find_ssk(msk, &local->addr, remote);
+	if (!ssk)
+		return -ESRCH;
+
+	spin_lock_bh(&msk->pm.lock);
+	mptcp_userspace_pm_delete_local_addr(msk, local);
+	spin_unlock_bh(&msk->pm.lock);
+	mptcp_subflow_shutdown(sk, ssk, RCV_SHUTDOWN | SEND_SHUTDOWN);
+	mptcp_close_ssk(sk, ssk, mptcp_subflow_ctx(ssk));
+	MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RMSUBFLOW);
+
+	return 0;
+}
+
 int mptcp_pm_nl_subflow_destroy_doit(struct sk_buff *skb, struct genl_info *info)
 {
 	struct mptcp_pm_addr_entry addr_l;
 	struct mptcp_addr_info addr_r;
 	struct nlattr *raddr, *laddr;
 	struct mptcp_sock *msk;
-	struct sock *sk, *ssk;
 	int err = -EINVAL;
+	struct sock *sk;
 
 	if (GENL_REQ_ATTR_CHECK(info, MPTCP_PM_ATTR_ADDR) ||
 	    GENL_REQ_ATTR_CHECK(info, MPTCP_PM_ATTR_ADDR_REMOTE))
@@ -XXX,XX +XXX,XX @@ int mptcp_pm_nl_subflow_destroy_doit(struct sk_buff *skb, struct genl_info *info
 	}
 
 	lock_sock(sk);
-	ssk = mptcp_nl_find_ssk(msk, &addr_l.addr, &addr_r);
-	if (!ssk) {
-		GENL_SET_ERR_MSG(info, "subflow not found");
-		err = -ESRCH;
-		goto release_sock;
-	}
-
-	spin_lock_bh(&msk->pm.lock);
-	mptcp_userspace_pm_delete_local_addr(msk, &addr_l);
-	spin_unlock_bh(&msk->pm.lock);
-	mptcp_subflow_shutdown(sk, ssk, RCV_SHUTDOWN | SEND_SHUTDOWN);
-	mptcp_close_ssk(sk, ssk, mptcp_subflow_ctx(ssk));
-	MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RMSUBFLOW);
-release_sock:
+	err = userspace_pm_subflow_destroy(msk, &addr_l, &addr_r);
 	release_sock(sk);
+	if (err)
+		GENL_SET_ERR_MSG(info, "subflow not found");
 
 destroy_err:
 	sock_put(sk);
 	return err;
 }
 
+static int userspace_pm_set_flags(struct mptcp_sock *msk,
+				  struct mptcp_pm_addr_entry *local,
+				  struct mptcp_addr_info *remote)
+{
+	struct mptcp_pm_addr_entry *entry;
+	u8 bkup = 0;
+
+	if (local->flags & MPTCP_PM_ADDR_FLAG_BACKUP)
+		bkup = 1;
+
+	spin_lock_bh(&msk->pm.lock);
+	entry = mptcp_userspace_pm_lookup_addr(msk, &local->addr);
+	if (entry) {
+		if (bkup)
+			entry->flags |= MPTCP_PM_ADDR_FLAG_BACKUP;
+		else
+			entry->flags &= ~MPTCP_PM_ADDR_FLAG_BACKUP;
+	}
+	spin_unlock_bh(&msk->pm.lock);
+
+	return mptcp_pm_nl_mp_prio_send_ack(msk, &local->addr, remote, bkup);
+}
+
 int mptcp_userspace_pm_set_flags(struct mptcp_pm_addr_entry *local,
 				 struct genl_info *info)
 {
 	struct mptcp_addr_info rem = { .family = AF_UNSPEC, };
-	struct mptcp_pm_addr_entry *entry;
 	struct nlattr *attr, *attr_rem;
 	struct mptcp_sock *msk;
 	int ret = -EINVAL;
 	struct sock *sk;
-	u8 bkup = 0;
 
 	if (GENL_REQ_ATTR_CHECK(info, MPTCP_PM_ATTR_ADDR_REMOTE))
 		return ret;
@@ -XXX,XX +XXX,XX @@ int mptcp_userspace_pm_set_flags(struct mptcp_pm_addr_entry *local,
 		goto set_flags_err;
 	}
 
-	if (local->flags & MPTCP_PM_ADDR_FLAG_BACKUP)
-		bkup = 1;
-
-	spin_lock_bh(&msk->pm.lock);
-	entry = mptcp_userspace_pm_lookup_addr(msk, &local->addr);
-	if (entry) {
-		if (bkup)
-			entry->flags |= MPTCP_PM_ADDR_FLAG_BACKUP;
-		else
-			entry->flags &= ~MPTCP_PM_ADDR_FLAG_BACKUP;
-	}
-	spin_unlock_bh(&msk->pm.lock);
-
 	lock_sock(sk);
-	ret = mptcp_pm_nl_mp_prio_send_ack(msk, &local->addr, &rem, bkup);
+	ret = userspace_pm_set_flags(msk, local, &rem);
 	release_sock(sk);
 
 	/* mptcp_pm_nl_mp_prio_send_ack() only fails in one case */
@@ -XXX,XX +XXX,XX @@ int mptcp_userspace_pm_get_addr(u8 id, struct mptcp_pm_addr_entry *addr,
 	return ret;
 }
 
+static struct mptcp_pm_ops mptcp_userspace_pm = {
+	.address_announce	= userspace_pm_address_announce,
+	.address_remove		= userspace_pm_address_remove,
+	.subflow_create		= userspace_pm_subflow_create,
+	.subflow_destroy	= userspace_pm_subflow_destroy,
+	.get_local_id		= userspace_pm_get_local_id,
+	.get_flags		= userspace_pm_get_flags,
+	.set_flags		= userspace_pm_set_flags,
+	.type			= MPTCP_PM_TYPE_USERSPACE,
+	.owner			= THIS_MODULE,
+};
+
 /* Must be called with rcu read lock held */
 struct mptcp_pm_ops *mptcp_pm_find(enum mptcp_pm_type type)
 {
@@ -XXX,XX +XXX,XX @@ int mptcp_register_path_manager(struct mptcp_pm_ops *pm)
 
 void mptcp_unregister_path_manager(struct mptcp_pm_ops *pm)
 {
+	if (pm == &mptcp_userspace_pm)
+		return;
+
 	spin_lock(&mptcp_pm_list_lock);
 	list_del_rcu(&pm->list);
 	spin_unlock(&mptcp_pm_list_lock);
 }
+
+void __init mptcp_userspace_pm_init(void)
+{
+	mptcp_register_path_manager(&mptcp_userspace_pm);
+}
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index XXXXXXX..XXXXXXX 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -XXX,XX +XXX,XX @@ static inline u8 subflow_get_local_id(const struct mptcp_subflow_context *subflo
 }
 
 void __init mptcp_pm_nl_init(void);
+void __init mptcp_userspace_pm_init(void);
 void mptcp_pm_nl_work(struct mptcp_sock *msk);
 unsigned int mptcp_pm_get_add_addr_signal_max(const struct mptcp_sock *msk);
 unsigned int mptcp_pm_get_add_addr_accept_max(const struct mptcp_sock *msk);
-- 
2.43.0

From: Geliang Tang <tanggeliang@kylinos.cn>

Add a struct mptcp_pm_ops pointer "ops" in struct mptcp_pm_data, and two
functions mptcp_init_pm() and mptcp_release_pm(), to set and release this
pointer. mptcp_init_pm() is invoked in mptcp_pm_data_reset(), while
mptcp_release_pm() is invoked in __mptcp_destroy_sock().

In this way, different userspace path managers can be initialized through
the pm_type sysctl, and then called into their respective interfaces
through "ops" of "msk->pm".

Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
---
 net/mptcp/pm.c           |  7 +++++
 net/mptcp/pm_userspace.c | 58 +++++++++++++++++++++++++++++++++++-----
 net/mptcp/protocol.c     |  1 +
 net/mptcp/protocol.h     |  3 +++
 4 files changed, 62 insertions(+), 7 deletions(-)

diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
index XXXXXXX..XXXXXXX 100644
--- a/net/mptcp/pm.c
+++ b/net/mptcp/pm.c
@@ -XXX,XX +XXX,XX @@ void mptcp_pm_data_reset(struct mptcp_sock *msk)
 {
 	u8 pm_type = mptcp_get_pm_type(sock_net((struct sock *)msk));
 	struct mptcp_pm_data *pm = &msk->pm;
+	int ret;
 
 	pm->add_addr_signaled = 0;
 	pm->add_addr_accepted = 0;
@@ -XXX,XX +XXX,XX @@ void mptcp_pm_data_reset(struct mptcp_sock *msk)
 		WRITE_ONCE(pm->work_pending, 0);
 		WRITE_ONCE(pm->accept_addr, 0);
 		WRITE_ONCE(pm->accept_subflow, 0);
+
+		rcu_read_lock();
+		ret = mptcp_init_pm(msk, mptcp_pm_find(pm_type));
+		rcu_read_unlock();
+		if (ret)
+			return;
 	}
 
 	WRITE_ONCE(pm->addr_signal, 0);
diff --git a/net/mptcp/pm_userspace.c b/net/mptcp/pm_userspace.c
index XXXXXXX..XXXXXXX 100644
--- a/net/mptcp/pm_userspace.c
+++ b/net/mptcp/pm_userspace.c
@@ -XXX,XX +XXX,XX @@ static int userspace_pm_get_local_id(struct mptcp_sock *msk,
 int mptcp_userspace_pm_get_local_id(struct mptcp_sock *msk,
 				    struct mptcp_pm_addr_entry *local)
 {
-	return userspace_pm_get_local_id(msk, local);
+	return msk->pm.ops->get_local_id ?
+	       msk->pm.ops->get_local_id(msk, local) :
+	       userspace_pm_get_local_id(msk, local);
 }
 
 static u8 userspace_pm_get_flags(struct mptcp_sock *msk,
@@ -XXX,XX +XXX,XX @@ static u8 userspace_pm_get_flags(struct mptcp_sock *msk,
 u8 mptcp_userspace_pm_get_flags(struct mptcp_sock *msk,
 				struct mptcp_addr_info *skc)
 {
-	return userspace_pm_get_flags(msk, skc);
+	return msk->pm.ops->get_flags ?
+	       msk->pm.ops->get_flags(msk, skc) :
+	       userspace_pm_get_flags(msk, skc);
 }
 
 static struct mptcp_sock *mptcp_userspace_pm_get_sock(const struct genl_info *info)
@@ -XXX,XX +XXX,XX @@ int mptcp_pm_nl_announce_doit(struct sk_buff *skb, struct genl_info *info)
 	}
 
 	lock_sock(sk);
-	err = userspace_pm_address_announce(msk, &addr_val);
+	err = msk->pm.ops->address_announce ?
+	      msk->pm.ops->address_announce(msk, &addr_val) :
+	      userspace_pm_address_announce(msk, &addr_val);
 	release_sock(sk);
 	if (err)
 		NL_SET_ERR_MSG_ATTR(info->extack, addr,
@@ -XXX,XX +XXX,XX @@ int mptcp_pm_nl_remove_doit(struct sk_buff *skb, struct genl_info *info)
 	sk = (struct sock *)msk;
 
 	lock_sock(sk);
-	err = userspace_pm_address_remove(msk, id_val);
+	err = msk->pm.ops->address_remove ?
+	      msk->pm.ops->address_remove(msk, id_val) :
+	      userspace_pm_address_remove(msk, id_val);
 	release_sock(sk);
 	if (err)
 		NL_SET_ERR_MSG_ATTR_FMT(info->extack, id,
@@ -XXX,XX +XXX,XX @@ int mptcp_pm_nl_subflow_create_doit(struct sk_buff *skb, struct genl_info *info)
 	}
 
 	lock_sock(sk);
-	err = userspace_pm_subflow_create(msk, &entry, &addr_r);
+	err = msk->pm.ops->subflow_create ?
+	      msk->pm.ops->subflow_create(msk, &entry, &addr_r) :
+	      userspace_pm_subflow_create(msk, &entry, &addr_r);
 	release_sock(sk);
 
 	if (err)
@@ -XXX,XX +XXX,XX @@ int mptcp_pm_nl_subflow_destroy_doit(struct sk_buff *skb, struct genl_info *info
 	}
 
 	lock_sock(sk);
-	err = userspace_pm_subflow_destroy(msk, &addr_l, &addr_r);
+	err = msk->pm.ops->subflow_destroy ?
+	      msk->pm.ops->subflow_destroy(msk, &addr_l, &addr_r) :
+	      userspace_pm_subflow_destroy(msk, &addr_l, &addr_r);
 	release_sock(sk);
 	if (err)
 		GENL_SET_ERR_MSG(info, "subflow not found");
@@ -XXX,XX +XXX,XX @@ int mptcp_userspace_pm_set_flags(struct mptcp_pm_addr_entry *local,
 	}
 
 	lock_sock(sk);
-	ret = userspace_pm_set_flags(msk, local, &rem);
+	ret = msk->pm.ops->set_flags ?
+	      msk->pm.ops->set_flags(msk, local, &rem) :
+	      userspace_pm_set_flags(msk, local, &rem);
 	release_sock(sk);
 
 	/* mptcp_pm_nl_mp_prio_send_ack() only fails in one case */
@@ -XXX,XX +XXX,XX @@ void mptcp_unregister_path_manager(struct mptcp_pm_ops *pm)
 	spin_unlock(&mptcp_pm_list_lock);
 }
 
+int mptcp_init_pm(struct mptcp_sock *msk, struct mptcp_pm_ops *pm)
+{
+	if (!pm)
+		pm = &mptcp_userspace_pm;
+
+	if (!bpf_try_module_get(pm, pm->owner))
+		return -EBUSY;
+
+	msk->pm.ops = pm;
+	if (msk->pm.ops->init)
+		msk->pm.ops->init(msk);
+
+	pr_debug("userspace_pm type %u initialized\n", msk->pm.ops->type);
+	return 0;
+}
+
+void mptcp_release_pm(struct mptcp_sock *msk)
+{
+	struct mptcp_pm_ops *pm = msk->pm.ops;
+
+	if (!pm)
+		return;
+
+	msk->pm.ops = NULL;
+	if (pm->release)
+		pm->release(msk);
+
+	bpf_module_put(pm, pm->owner);
+}
+
 void __init mptcp_userspace_pm_init(void)
 {
 	mptcp_register_path_manager(&mptcp_userspace_pm);
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index XXXXXXX..XXXXXXX 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -XXX,XX +XXX,XX @@ static void __mptcp_destroy_sock(struct sock *sk)
 	sk_stop_timer(sk, &sk->sk_timer);
 	msk->pm.status = 0;
 	mptcp_release_sched(msk);
+	mptcp_release_pm(msk);
 
 	sk->sk_prot->destroy(sk);
 
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index XXXXXXX..XXXXXXX 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -XXX,XX +XXX,XX @@ struct mptcp_pm_data {
 	struct mptcp_addr_info remote;
 	struct list_head anno_list;
 	struct list_head userspace_pm_local_addr_list;
+	struct mptcp_pm_ops *ops;
 
 	spinlock_t	lock;		/*protects the whole PM data */
 
@@ -XXX,XX +XXX,XX @@ struct mptcp_pm_ops *mptcp_pm_find(enum mptcp_pm_type type);
 int mptcp_validate_path_manager(struct mptcp_pm_ops *pm);
 int mptcp_register_path_manager(struct mptcp_pm_ops *pm);
 void mptcp_unregister_path_manager(struct mptcp_pm_ops *pm);
+int mptcp_init_pm(struct mptcp_sock *msk, struct mptcp_pm_ops *pm);
+void mptcp_release_pm(struct mptcp_sock *msk);
 
 void mptcp_free_local_addr_list(struct mptcp_sock *msk);
 
-- 
2.43.0

From: Geliang Tang <tanggeliang@kylinos.cn>

v5:
 - use "struct mptcp_pm_param *param" as unified parameters for all
   interfaces.
 - register in-kernel mptcp_pm_ops too.
 - only implement two interfaces "get_local_id" and "get_priority" in
   this set.

v4:
 - include a new patch "define BPF path manager type".

- add new interfaces:
	created established closed
	listerner_created listener_closed

- rename interfaces as:
	address_announced address_removed
	subflow_established subflow_closed
	get_priority set_priority

- rename functions as:
	mptcp_pm_validate
	mptcp_pm_register
	mptcp_pm_unregister
	mptcp_pm_initialize
	mptcp_pm_release

v3:
 - rename the 2nd parameter of get_local_id() from 'local' to 'skc'.
 - keep the 'msk_sport' check in mptcp_userspace_pm_get_local_id().
 - return 'err' instead of '0' in userspace_pm_subflow_create().
 - drop 'ret' variable inmptcp_pm_data_reset().
 - fix typos in commit log.

v2:
 - update get_local_id interface in patch 2.

get_addr() and dump_addr() interfaces of BPF userspace pm are dropped
as Matt suggested.

In order to implement BPF path manager, it's necessary to unify the
interfaces of the path manager. This set contains some cleanups and
refactoring to unify the interfaces in kernel space. Finally, define
a struct mptcp_pm_ops for a path manager.

Geliang Tang (9):
  mptcp: pm: use addr entry for get_local_id
  mptcp: pm: add struct mptcp_pm_param
  mptcp: pm: pass pm_param to get_local_id
  mptcp: pm: define struct mptcp_pm_ops
  mptcp: pm: in-kernel: register mptcp_netlink_pm
  mptcp: pm: userspace: register mptcp_userspace_pm
  mptcp: pm: initialize and release mptcp_pm_ops
  mptcp: pm: drop get_local_id helpers
  mptcp: pm: drop is_backup helpers

-- 
2.43.0

From: Geliang Tang <tanggeliang@kylinos.cn>

The following code in mptcp_userspace_pm_get_local_id() that assigns "skc"
to "new_entry" is not allowed in BPF if we use the same code to implement
the get_local_id() interface of a BFP path manager:

memset(&new_entry, 0, sizeof(struct mptcp_pm_addr_entry));
	new_entry.addr = *skc;
	new_entry.addr.id = 0;
	new_entry.flags = MPTCP_PM_ADDR_FLAG_IMPLICIT;

To solve the issue, this patch moves this assignment to "new_entry" forward
to mptcp_pm_get_local_id(), and then passing "new_entry" as a parameter to
both mptcp_pm_nl_get_local_id() and mptcp_userspace_pm_get_local_id().

Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
---
 net/mptcp/pm.c           | 11 ++++++++---
 net/mptcp/pm_netlink.c   |  9 ++++-----
 net/mptcp/pm_userspace.c | 17 ++++++-----------
 net/mptcp/protocol.h     |  6 ++++--
 4 files changed, 22 insertions(+), 21 deletions(-)

diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
index XXXXXXX..XXXXXXX 100644
--- a/net/mptcp/pm.c
+++ b/net/mptcp/pm.c
@@ -XXX,XX +XXX,XX @@ 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)
 {
-	struct mptcp_addr_info skc_local;
+	struct mptcp_pm_addr_entry skc_local;
 	struct mptcp_addr_info msk_local;
 
 	if (WARN_ON_ONCE(!msk))
 		return -1;
 
+	memset(&skc_local, 0, sizeof(struct mptcp_pm_addr_entry));
+
 	/* The 0 ID mapping is defined by the first subflow, copied into the msk
 	 * addr
 	 */
 	mptcp_local_address((struct sock_common *)msk, &msk_local);
-	mptcp_local_address((struct sock_common *)skc, &skc_local);
-	if (mptcp_addresses_equal(&msk_local, &skc_local, false))
+	mptcp_local_address((struct sock_common *)skc, &skc_local.addr);
+	if (mptcp_addresses_equal(&msk_local, &skc_local.addr, false))
 		return 0;
 
+	skc_local.addr.id = 0;
+	skc_local.flags = MPTCP_PM_ADDR_FLAG_IMPLICIT;
+
 	if (mptcp_pm_is_userspace(msk))
 		return mptcp_userspace_pm_get_local_id(msk, &skc_local);
 	return mptcp_pm_nl_get_local_id(msk, &skc_local);
diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index XXXXXXX..XXXXXXX 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -XXX,XX +XXX,XX @@ static int mptcp_pm_nl_create_listen_socket(struct sock *sk,
 	return err;
 }
 
-int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct mptcp_addr_info *skc)
+int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk,
+			     struct mptcp_pm_addr_entry *skc)
 {
 	struct mptcp_pm_addr_entry *entry;
 	struct pm_nl_pernet *pernet;
@@ -XXX,XX +XXX,XX @@ int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct mptcp_addr_info *skc
 	pernet = pm_nl_get_pernet_from_msk(msk);
 
 	rcu_read_lock();
-	entry = __lookup_addr(pernet, skc);
+	entry = __lookup_addr(pernet, &skc->addr);
 	ret = entry ? entry->addr.id : -1;
 	rcu_read_unlock();
 	if (ret >= 0)
@@ -XXX,XX +XXX,XX @@ int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct mptcp_addr_info *skc
 	if (!entry)
 		return -ENOMEM;
 
-	entry->addr = *skc;
-	entry->addr.id = 0;
+	*entry = *skc;
 	entry->addr.port = 0;
 	entry->ifindex = 0;
-	entry->flags = MPTCP_PM_ADDR_FLAG_IMPLICIT;
 	entry->lsk = NULL;
 	ret = mptcp_pm_nl_append_new_local_addr(pernet, entry, true);
 	if (ret < 0)
diff --git a/net/mptcp/pm_userspace.c b/net/mptcp/pm_userspace.c
index XXXXXXX..XXXXXXX 100644
--- a/net/mptcp/pm_userspace.c
+++ b/net/mptcp/pm_userspace.c
@@ -XXX,XX +XXX,XX @@ mptcp_userspace_pm_lookup_addr_by_id(struct mptcp_sock *msk, unsigned int id)
 }
 
 int mptcp_userspace_pm_get_local_id(struct mptcp_sock *msk,
-				    struct mptcp_addr_info *skc)
+				    struct mptcp_pm_addr_entry *skc)
 {
-	struct mptcp_pm_addr_entry *entry = NULL, new_entry;
 	__be16 msk_sport =  ((struct inet_sock *)
 			     inet_sk((struct sock *)msk))->inet_sport;
+	struct mptcp_pm_addr_entry *entry;
 
 	spin_lock_bh(&msk->pm.lock);
-	entry = mptcp_userspace_pm_lookup_addr(msk, skc);
+	entry = mptcp_userspace_pm_lookup_addr(msk, &skc->addr);
 	spin_unlock_bh(&msk->pm.lock);
 	if (entry)
 		return entry->addr.id;
 
-	memset(&new_entry, 0, sizeof(struct mptcp_pm_addr_entry));
-	new_entry.addr = *skc;
-	new_entry.addr.id = 0;
-	new_entry.flags = MPTCP_PM_ADDR_FLAG_IMPLICIT;
-
-	if (new_entry.addr.port == msk_sport)
-		new_entry.addr.port = 0;
+	if (skc->addr.port == msk_sport)
+		skc->addr.port = 0;
 
-	return mptcp_userspace_pm_append_new_local_addr(msk, &new_entry, true);
+	return mptcp_userspace_pm_append_new_local_addr(msk, skc, true);
 }
 
 bool mptcp_userspace_pm_is_backup(struct mptcp_sock *msk,
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index XXXXXXX..XXXXXXX 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -XXX,XX +XXX,XX @@ bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, const struct sk_buff *skb,
 bool mptcp_pm_rm_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
 			     struct mptcp_rm_list *rm_list);
 int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc);
-int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct mptcp_addr_info *skc);
-int mptcp_userspace_pm_get_local_id(struct mptcp_sock *msk, struct mptcp_addr_info *skc);
+int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk,
+			     struct mptcp_pm_addr_entry *skc);
+int mptcp_userspace_pm_get_local_id(struct mptcp_sock *msk,
+				    struct mptcp_pm_addr_entry *skc);
 bool mptcp_pm_is_backup(struct mptcp_sock *msk, struct sock_common *skc);
 bool mptcp_pm_nl_is_backup(struct mptcp_sock *msk, struct mptcp_addr_info *skc);
 bool mptcp_userspace_pm_is_backup(struct mptcp_sock *msk, struct mptcp_addr_info *skc);
-- 
2.43.0

From: Geliang Tang <tanggeliang@kylinos.cn>

Generally, in the path manager interfaces, the local address is defined
as an mptcp_pm_addr_entry type address, while the remote address is
defined as an mptcp_addr_info type one:

(struct mptcp_pm_addr_entry *local, struct mptcp_addr_info *remote)

In order to make these interfaces more flexible and extensible, a struct
mptcp_pm_param is defined here to pass parameters. "entry" can be used
as the local address entry, and "addr" can be used as the remote address.

Also add a new helper mptcp_pm_param_set_contexts() to set a struct
mptcp_pm_param type parameter.

Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
---
 include/net/mptcp.h  | 13 +++++++++++++
 net/mptcp/pm.c       | 10 ++++++++++
 net/mptcp/protocol.h | 11 +++--------
 3 files changed, 26 insertions(+), 8 deletions(-)

diff --git a/include/net/mptcp.h b/include/net/mptcp.h
index XXXXXXX..XXXXXXX 100644
--- a/include/net/mptcp.h
+++ b/include/net/mptcp.h
@@ -XXX,XX +XXX,XX @@ struct mptcp_sched_ops {
 	void (*release)(struct mptcp_sock *msk);
 } ____cacheline_aligned_in_smp;
 
+struct mptcp_pm_addr_entry {
+	struct list_head	list;
+	struct mptcp_addr_info	addr;
+	u8			flags;
+	int			ifindex;
+	struct socket		*lsk;
+};
+
+struct mptcp_pm_param {
+	struct mptcp_pm_addr_entry	entry;
+	struct mptcp_addr_info		addr;
+};
+
 #ifdef CONFIG_MPTCP
 void mptcp_init(void);
 
diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
index XXXXXXX..XXXXXXX 100644
--- a/net/mptcp/pm.c
+++ b/net/mptcp/pm.c
@@ -XXX,XX +XXX,XX @@ bool mptcp_pm_rm_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
 	return ret;
 }
 
+void mptcp_pm_param_set_contexts(struct mptcp_pm_param *param,
+				 const struct mptcp_pm_addr_entry *entry,
+				 const struct mptcp_addr_info *addr)
+{
+	if (entry)
+		param->entry = *entry;
+	if (addr)
+		param->addr = *addr;
+}
+
 int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc)
 {
 	struct mptcp_pm_addr_entry skc_local;
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index XXXXXXX..XXXXXXX 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -XXX,XX +XXX,XX @@ struct mptcp_pm_local {
 	int			ifindex;
 };
 
-struct mptcp_pm_addr_entry {
-	struct list_head	list;
-	struct mptcp_addr_info	addr;
-	u8			flags;
-	int			ifindex;
-	struct socket		*lsk;
-};
-
 struct mptcp_data_frag {
 	struct list_head list;
 	u64 data_seq;
@@ -XXX,XX +XXX,XX @@ bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, const struct sk_buff *skb,
 			      bool *drop_other_suboptions);
 bool mptcp_pm_rm_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
 			     struct mptcp_rm_list *rm_list);
+void mptcp_pm_param_set_contexts(struct mptcp_pm_param *param,
+				 const struct mptcp_pm_addr_entry *entry,
+				 const struct mptcp_addr_info *addr);
 int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc);
 int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk,
 			     struct mptcp_pm_addr_entry *skc);
-- 
2.43.0

From: Geliang Tang <tanggeliang@kylinos.cn>

This patch changes the 2nd parameter of get_local_id() interface as
"struct mptcp_pm_param" type. Only "entry" member of this struct is
used.

Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
---
 net/mptcp/pm.c           | 6 ++++--
 net/mptcp/pm_netlink.c   | 3 ++-
 net/mptcp/pm_userspace.c | 3 ++-
 net/mptcp/protocol.h     | 4 ++--
 4 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
index XXXXXXX..XXXXXXX 100644
--- a/net/mptcp/pm.c
+++ b/net/mptcp/pm.c
@@ -XXX,XX +XXX,XX @@ int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc)
 {
 	struct mptcp_pm_addr_entry skc_local;
 	struct mptcp_addr_info msk_local;
+	struct mptcp_pm_param param;
 
 	if (WARN_ON_ONCE(!msk))
 		return -1;
@@ -XXX,XX +XXX,XX @@ int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc)
 	skc_local.addr.id = 0;
 	skc_local.flags = MPTCP_PM_ADDR_FLAG_IMPLICIT;
 
+	mptcp_pm_param_set_contexts(&param, &skc_local, NULL);
 	if (mptcp_pm_is_userspace(msk))
-		return mptcp_userspace_pm_get_local_id(msk, &skc_local);
-	return mptcp_pm_nl_get_local_id(msk, &skc_local);
+		return mptcp_userspace_pm_get_local_id(msk, &param);
+	return mptcp_pm_nl_get_local_id(msk, &param);
 }
 
 bool mptcp_pm_is_backup(struct mptcp_sock *msk, struct sock_common *skc)
diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index XXXXXXX..XXXXXXX 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -XXX,XX +XXX,XX @@ static int mptcp_pm_nl_create_listen_socket(struct sock *sk,
 }
 
 int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk,
-			     struct mptcp_pm_addr_entry *skc)
+			     struct mptcp_pm_param *param)
 {
+	struct mptcp_pm_addr_entry *skc = &param->entry;
 	struct mptcp_pm_addr_entry *entry;
 	struct pm_nl_pernet *pernet;
 	int ret;
diff --git a/net/mptcp/pm_userspace.c b/net/mptcp/pm_userspace.c
index XXXXXXX..XXXXXXX 100644
--- a/net/mptcp/pm_userspace.c
+++ b/net/mptcp/pm_userspace.c
@@ -XXX,XX +XXX,XX @@ mptcp_userspace_pm_lookup_addr_by_id(struct mptcp_sock *msk, unsigned int id)
 }
 
 int mptcp_userspace_pm_get_local_id(struct mptcp_sock *msk,
-				    struct mptcp_pm_addr_entry *skc)
+				    struct mptcp_pm_param *param)
 {
 	__be16 msk_sport =  ((struct inet_sock *)
 			     inet_sk((struct sock *)msk))->inet_sport;
+	struct mptcp_pm_addr_entry *skc = &param->entry;
 	struct mptcp_pm_addr_entry *entry;
 
 	spin_lock_bh(&msk->pm.lock);
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index XXXXXXX..XXXXXXX 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -XXX,XX +XXX,XX @@ void mptcp_pm_param_set_contexts(struct mptcp_pm_param *param,
 				 const struct mptcp_addr_info *addr);
 int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc);
 int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk,
-			     struct mptcp_pm_addr_entry *skc);
+			     struct mptcp_pm_param *param);
 int mptcp_userspace_pm_get_local_id(struct mptcp_sock *msk,
-				    struct mptcp_pm_addr_entry *skc);
+				    struct mptcp_pm_param *param);
 bool mptcp_pm_is_backup(struct mptcp_sock *msk, struct sock_common *skc);
 bool mptcp_pm_nl_is_backup(struct mptcp_sock *msk, struct mptcp_addr_info *skc);
 bool mptcp_userspace_pm_is_backup(struct mptcp_sock *msk, struct mptcp_addr_info *skc);
-- 
2.43.0

From: Geliang Tang <tanggeliang@kylinos.cn>

In order to allow users to develop their own BPF-based path manager,
this patch defines a struct ops "mptcp_pm_ops" for a userspace path
manager, which contains a set of interfaces.

Add a set of functions to register, unregister, find and validate a
given struct ops.

Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
---
 include/net/mptcp.h  | 29 ++++++++++++++++++++++
 net/mptcp/pm.c       | 59 ++++++++++++++++++++++++++++++++++++++++++++
 net/mptcp/protocol.h |  5 ++++
 3 files changed, 93 insertions(+)

diff --git a/include/net/mptcp.h b/include/net/mptcp.h
index XXXXXXX..XXXXXXX 100644
--- a/include/net/mptcp.h
+++ b/include/net/mptcp.h
@@ -XXX,XX +XXX,XX @@ struct mptcp_pm_param {
 	struct mptcp_addr_info		addr;
 };
 
+struct mptcp_pm_ops {
+	int (*created)(struct mptcp_sock *msk);
+	int (*established)(struct mptcp_sock *msk);
+	int (*closed)(struct mptcp_sock *msk);
+	int (*address_announced)(struct mptcp_sock *msk,
+				 struct mptcp_pm_param *param);
+	int (*address_removed)(struct mptcp_sock *msk,
+			       struct mptcp_pm_param *param);
+	int (*subflow_established)(struct mptcp_sock *msk,
+				   struct mptcp_pm_param *param);
+	int (*subflow_closed)(struct mptcp_sock *msk,
+			      struct mptcp_pm_param *param);
+	int (*get_local_id)(struct mptcp_sock *msk,
+			    struct mptcp_pm_param *param);
+	bool (*get_priority)(struct mptcp_sock *msk,
+			     struct mptcp_pm_param *param);
+	int (*set_priority)(struct mptcp_sock *msk,
+			    struct mptcp_pm_param *param);
+	int (*listener_created)(struct mptcp_sock *msk);
+	int (*listener_closed)(struct mptcp_sock *msk);
+
+	u8			type;
+	struct module		*owner;
+	struct list_head	list;
+
+	void (*init)(struct mptcp_sock *msk);
+	void (*release)(struct mptcp_sock *msk);
+} ____cacheline_aligned_in_smp;
+
 #ifdef CONFIG_MPTCP
 void mptcp_init(void);
 
diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
index XXXXXXX..XXXXXXX 100644
--- a/net/mptcp/pm.c
+++ b/net/mptcp/pm.c
@@ -XXX,XX +XXX,XX @@
 #define pr_fmt(fmt) "MPTCP: " fmt
 
 #include <linux/kernel.h>
+#include <linux/rculist.h>
+#include <linux/spinlock.h>
 #include <net/mptcp.h>
 #include "protocol.h"
 
 #include "mib.h"
 #include "mptcp_pm_gen.h"
 
+static DEFINE_SPINLOCK(mptcp_pm_list_lock);
+static LIST_HEAD(mptcp_pm_list);
+
 /* path manager command handlers */
 
 int mptcp_pm_announce_addr(struct mptcp_sock *msk,
@@ -XXX,XX +XXX,XX @@ void __init mptcp_pm_init(void)
 {
 	mptcp_pm_nl_init();
 }
+
+/* Must be called with rcu read lock held */
+struct mptcp_pm_ops *mptcp_pm_find(enum mptcp_pm_type type)
+{
+	struct mptcp_pm_ops *pm;
+
+	list_for_each_entry_rcu(pm, &mptcp_pm_list, list) {
+		if (pm->type == type)
+			return pm;
+	}
+
+	return NULL;
+}
+
+int mptcp_pm_validate(struct mptcp_pm_ops *pm)
+{
+	if (!pm->created && !pm->established && !pm->closed &&
+	    !pm->address_announced && !pm->address_removed &&
+	    !pm->subflow_established && !pm->subflow_closed &&
+	    !pm->get_local_id && !pm->get_priority && !pm->set_priority &&
+	    !pm->listener_created && !pm->listener_closed) {
+		pr_err("%u does not implement required ops\n", pm->type);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+int mptcp_pm_register(struct mptcp_pm_ops *pm)
+{
+	int ret;
+
+	ret = mptcp_pm_validate(pm);
+	if (ret)
+		return ret;
+
+	spin_lock(&mptcp_pm_list_lock);
+	if (mptcp_pm_find(pm->type)) {
+		spin_unlock(&mptcp_pm_list_lock);
+		return -EEXIST;
+	}
+	list_add_tail_rcu(&pm->list, &mptcp_pm_list);
+	spin_unlock(&mptcp_pm_list_lock);
+
+	pr_debug("userspace_pm type %u registered\n", pm->type);
+	return 0;
+}
+
+void mptcp_pm_unregister(struct mptcp_pm_ops *pm)
+{
+	spin_lock(&mptcp_pm_list_lock);
+	list_del_rcu(&pm->list);
+	spin_unlock(&mptcp_pm_list_lock);
+}
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index XXXXXXX..XXXXXXX 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -XXX,XX +XXX,XX @@ int mptcp_pm_remove_addr(struct mptcp_sock *msk, const struct mptcp_rm_list *rm_
 void mptcp_pm_remove_addr_entry(struct mptcp_sock *msk,
 				struct mptcp_pm_addr_entry *entry);
 
+struct mptcp_pm_ops *mptcp_pm_find(enum mptcp_pm_type type);
+int mptcp_pm_validate(struct mptcp_pm_ops *pm);
+int mptcp_pm_register(struct mptcp_pm_ops *pm);
+void mptcp_pm_unregister(struct mptcp_pm_ops *pm);
+
 void mptcp_free_local_addr_list(struct mptcp_sock *msk);
 
 void mptcp_event(enum mptcp_event_type type, const struct mptcp_sock *msk,
-- 
2.43.0

From: Geliang Tang <tanggeliang@kylinos.cn>

This patch defines the original in-kernel netlink path manager as a new
struct mptcp_pm_ops named "mptcp_netlink_pm", and register it in
mptcp_pm_nl_init().

Only get_local_id() and get_priority() interfaces are implemented here.
mptcp_pm_nl_is_backup() becomes a wrapper of get_priority().

Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
---
 net/mptcp/pm_netlink.c | 21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index XXXXXXX..XXXXXXX 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -XXX,XX +XXX,XX @@ int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk,
 	return ret;
 }
 
-bool mptcp_pm_nl_is_backup(struct mptcp_sock *msk, struct mptcp_addr_info *skc)
+static bool mptcp_pm_nl_get_priority(struct mptcp_sock *msk,
+				     struct mptcp_pm_param *param)
 {
 	struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
+	struct mptcp_addr_info *skc = &param->addr;
 	struct mptcp_pm_addr_entry *entry;
 	bool backup;
 
@@ -XXX,XX +XXX,XX @@ bool mptcp_pm_nl_is_backup(struct mptcp_sock *msk, struct mptcp_addr_info *skc)
 	return backup;
 }
 
+bool mptcp_pm_nl_is_backup(struct mptcp_sock *msk, struct mptcp_addr_info *skc)
+{
+	struct mptcp_pm_param param;
+
+	mptcp_pm_param_set_contexts(&param, NULL, skc);
+	return mptcp_pm_nl_get_priority(msk, &param);
+}
+
 #define MPTCP_PM_CMD_GRP_OFFSET       0
 #define MPTCP_PM_EV_GRP_OFFSET        1
 
@@ -XXX,XX +XXX,XX @@ static struct pernet_operations mptcp_pm_pernet_ops = {
 	.size = sizeof(struct pm_nl_pernet),
 };
 
+static struct mptcp_pm_ops mptcp_netlink_pm = {
+	.get_local_id		= mptcp_pm_nl_get_local_id,
+	.get_priority		= mptcp_pm_nl_get_priority,
+	.type			= MPTCP_PM_TYPE_KERNEL,
+	.owner			= THIS_MODULE,
+};
+
 void __init mptcp_pm_nl_init(void)
 {
 	if (register_pernet_subsys(&mptcp_pm_pernet_ops) < 0)
@@ -XXX,XX +XXX,XX @@ void __init mptcp_pm_nl_init(void)
 
 	if (genl_register_family(&mptcp_genl_family))
 		panic("Failed to register MPTCP PM netlink family\n");
+
+	mptcp_pm_register(&mptcp_netlink_pm);
 }
-- 
2.43.0

From: Geliang Tang <tanggeliang@kylinos.cn>

This patch defines the original userspace path manager as a new struct
mptcp_pm_ops named "mptcp_userspace_pm", and register it in
mptcp_pm_data_init().

Only get_local_id() and get_priority() interfaces are implemented here.
mptcp_userspace_pm_is_backup() becomes a wrapper of get_priority().

Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
---
 net/mptcp/pm.c           |  1 +
 net/mptcp/pm_userspace.c | 26 ++++++++++++++++++++++++--
 net/mptcp/protocol.h     |  1 +
 3 files changed, 26 insertions(+), 2 deletions(-)

From: Geliang Tang <tanggeliang@kylinos.cn>

Add a struct mptcp_pm_ops pointer "ops" in struct mptcp_pm_data, and two
functions mptcp_pm_initialize() and mptcp_pm_release(), to set and release
this pointer. mptcp_pm_initialize() is invoked in mptcp_pm_data_reset(),
while mptcp_pm_release() is invoked in __mptcp_destroy_sock().

Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
---
 net/mptcp/pm.c       | 33 +++++++++++++++++++++++++++++++++
 net/mptcp/protocol.c |  1 +
 net/mptcp/protocol.h |  3 +++
 3 files changed, 37 insertions(+)

diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
index XXXXXXX..XXXXXXX 100644
--- a/net/mptcp/pm.c
+++ b/net/mptcp/pm.c
@@ -XXX,XX +XXX,XX @@ void mptcp_pm_data_reset(struct mptcp_sock *msk)
 	pm->rm_list_tx.nr = 0;
 	pm->rm_list_rx.nr = 0;
 	WRITE_ONCE(pm->pm_type, pm_type);
+	rcu_read_lock();
+	mptcp_pm_initialize(msk, mptcp_pm_find(pm_type));
+	rcu_read_unlock();
 
 	if (pm_type == MPTCP_PM_TYPE_KERNEL) {
 		bool subflows_allowed = !!mptcp_pm_get_subflows_max(msk);
@@ -XXX,XX +XXX,XX @@ void mptcp_pm_unregister(struct mptcp_pm_ops *pm)
 	list_del_rcu(&pm->list);
 	spin_unlock(&mptcp_pm_list_lock);
 }
+
+int mptcp_pm_initialize(struct mptcp_sock *msk, struct mptcp_pm_ops *pm)
+{
+	if (!pm)
+		return -EINVAL;
+
+	if (!bpf_try_module_get(pm, pm->owner))
+		return -EBUSY;
+
+	msk->pm.ops = pm;
+	if (msk->pm.ops->init)
+		msk->pm.ops->init(msk);
+
+	pr_debug("userspace_pm type %u initialized\n", msk->pm.ops->type);
+	return 0;
+}
+
+void mptcp_pm_release(struct mptcp_sock *msk)
+{
+	struct mptcp_pm_ops *pm = msk->pm.ops;
+
+	if (!pm)
+		return;
+
+	msk->pm.ops = NULL;
+	if (pm->release)
+		pm->release(msk);
+
+	bpf_module_put(pm, pm->owner);
+}
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index XXXXXXX..XXXXXXX 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -XXX,XX +XXX,XX @@ static void __mptcp_destroy_sock(struct sock *sk)
 	sk_stop_timer(sk, &sk->sk_timer);
 	msk->pm.status = 0;
 	mptcp_release_sched(msk);
+	mptcp_pm_release(msk);
 
 	sk->sk_prot->destroy(sk);
 
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index XXXXXXX..XXXXXXX 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -XXX,XX +XXX,XX @@ struct mptcp_pm_data {
 	struct mptcp_addr_info remote;
 	struct list_head anno_list;
 	struct list_head userspace_pm_local_addr_list;
+	struct mptcp_pm_ops *ops;
 
 	spinlock_t	lock;		/*protects the whole PM data */
 
@@ -XXX,XX +XXX,XX @@ struct mptcp_pm_ops *mptcp_pm_find(enum mptcp_pm_type type);
 int mptcp_pm_validate(struct mptcp_pm_ops *pm);
 int mptcp_pm_register(struct mptcp_pm_ops *pm);
 void mptcp_pm_unregister(struct mptcp_pm_ops *pm);
+int mptcp_pm_initialize(struct mptcp_sock *msk, struct mptcp_pm_ops *pm);
+void mptcp_pm_release(struct mptcp_sock *msk);
 
 void mptcp_free_local_addr_list(struct mptcp_sock *msk);
 
-- 
2.43.0

From: Geliang Tang <tanggeliang@kylinos.cn>

Now mptcp_pm_nl_get_local_id() and mptcp_userspace_pm_get_local_id()
helpers can be dropped, and mptcp_pm_get_local_id() can directly invoke
get_local_id() interface through "ops" of "msk->pm".

Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
---
 net/mptcp/pm.c           | 6 +++---
 net/mptcp/pm_netlink.c   | 4 ++--
 net/mptcp/pm_userspace.c | 4 ++--
 net/mptcp/protocol.h     | 4 ----
 4 files changed, 7 insertions(+), 11 deletions(-)

diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
index XXXXXXX..XXXXXXX 100644
--- a/net/mptcp/pm.c
+++ b/net/mptcp/pm.c
@@ -XXX,XX +XXX,XX @@ int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc)
 	skc_local.addr.id = 0;
 	skc_local.flags = MPTCP_PM_ADDR_FLAG_IMPLICIT;
 
+	if (!msk->pm.ops || !msk->pm.ops->get_local_id)
+		return -ENOTSUPP;
 	mptcp_pm_param_set_contexts(&param, &skc_local, NULL);
-	if (mptcp_pm_is_userspace(msk))
-		return mptcp_userspace_pm_get_local_id(msk, &param);
-	return mptcp_pm_nl_get_local_id(msk, &param);
+	return msk->pm.ops->get_local_id(msk, &param);
 }
 
 bool mptcp_pm_is_backup(struct mptcp_sock *msk, struct sock_common *skc)
diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index XXXXXXX..XXXXXXX 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -XXX,XX +XXX,XX @@ static int mptcp_pm_nl_create_listen_socket(struct sock *sk,
 	return err;
 }
 
-int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk,
-			     struct mptcp_pm_param *param)
+static int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk,
+				    struct mptcp_pm_param *param)
 {
 	struct mptcp_pm_addr_entry *skc = &param->entry;
 	struct mptcp_pm_addr_entry *entry;
diff --git a/net/mptcp/pm_userspace.c b/net/mptcp/pm_userspace.c
index XXXXXXX..XXXXXXX 100644
--- a/net/mptcp/pm_userspace.c
+++ b/net/mptcp/pm_userspace.c
@@ -XXX,XX +XXX,XX @@ mptcp_userspace_pm_lookup_addr_by_id(struct mptcp_sock *msk, unsigned int id)
 	return NULL;
 }
 
-int mptcp_userspace_pm_get_local_id(struct mptcp_sock *msk,
-				    struct mptcp_pm_param *param)
+static int mptcp_userspace_pm_get_local_id(struct mptcp_sock *msk,
+					   struct mptcp_pm_param *param)
 {
 	__be16 msk_sport =  ((struct inet_sock *)
 			     inet_sk((struct sock *)msk))->inet_sport;
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index XXXXXXX..XXXXXXX 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -XXX,XX +XXX,XX @@ void mptcp_pm_param_set_contexts(struct mptcp_pm_param *param,
 				 const struct mptcp_pm_addr_entry *entry,
 				 const struct mptcp_addr_info *addr);
 int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc);
-int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk,
-			     struct mptcp_pm_param *param);
-int mptcp_userspace_pm_get_local_id(struct mptcp_sock *msk,
-				    struct mptcp_pm_param *param);
 bool mptcp_pm_is_backup(struct mptcp_sock *msk, struct sock_common *skc);
 bool mptcp_pm_nl_is_backup(struct mptcp_sock *msk, struct mptcp_addr_info *skc);
 bool mptcp_userspace_pm_is_backup(struct mptcp_sock *msk, struct mptcp_addr_info *skc);
-- 
2.43.0

From: Geliang Tang <tanggeliang@kylinos.cn>

Now mptcp_pm_nl_is_backup() and mptcp_userspace_pm_is_backup()
helpers can be dropped, and mptcp_pm_is_backup() can directly
invoke get_priority() interface through "ops" of "msk->pm".

Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
---
 net/mptcp/pm.c           | 9 +++++----
 net/mptcp/pm_netlink.c   | 8 --------
 net/mptcp/pm_userspace.c | 9 ---------
 net/mptcp/protocol.h     | 2 --
 4 files changed, 5 insertions(+), 23 deletions(-)

diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
index XXXXXXX..XXXXXXX 100644
--- a/net/mptcp/pm.c
+++ b/net/mptcp/pm.c
@@ -XXX,XX +XXX,XX @@ int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc)
 bool mptcp_pm_is_backup(struct mptcp_sock *msk, struct sock_common *skc)
 {
 	struct mptcp_addr_info skc_local;
+	struct mptcp_pm_param param;
 
 	mptcp_local_address((struct sock_common *)skc, &skc_local);
 
-	if (mptcp_pm_is_userspace(msk))
-		return mptcp_userspace_pm_is_backup(msk, &skc_local);
-
-	return mptcp_pm_nl_is_backup(msk, &skc_local);
+	if (!msk->pm.ops || !msk->pm.ops->get_priority)
+		return -ENOTSUPP;
+	mptcp_pm_param_set_contexts(&param, NULL, &skc_local);
+	return msk->pm.ops->get_priority(msk, &param);
 }
 
 static int mptcp_pm_get_addr(u8 id, struct mptcp_pm_addr_entry *addr,
diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index XXXXXXX..XXXXXXX 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -XXX,XX +XXX,XX @@ static bool mptcp_pm_nl_get_priority(struct mptcp_sock *msk,
 	return backup;
 }
 
-bool mptcp_pm_nl_is_backup(struct mptcp_sock *msk, struct mptcp_addr_info *skc)
-{
-	struct mptcp_pm_param param;
-
-	mptcp_pm_param_set_contexts(&param, NULL, skc);
-	return mptcp_pm_nl_get_priority(msk, &param);
-}
-
 #define MPTCP_PM_CMD_GRP_OFFSET       0
 #define MPTCP_PM_EV_GRP_OFFSET        1
 
diff --git a/net/mptcp/pm_userspace.c b/net/mptcp/pm_userspace.c
index XXXXXXX..XXXXXXX 100644
--- a/net/mptcp/pm_userspace.c
+++ b/net/mptcp/pm_userspace.c
@@ -XXX,XX +XXX,XX @@ static bool mptcp_userspace_pm_get_priority(struct mptcp_sock *msk,
 	return backup;
 }
 
-bool mptcp_userspace_pm_is_backup(struct mptcp_sock *msk,
-				  struct mptcp_addr_info *skc)
-{
-	struct mptcp_pm_param param;
-
-	mptcp_pm_param_set_contexts(&param, NULL, skc);
-	return mptcp_userspace_pm_get_priority(msk, &param);
-}
-
 static struct mptcp_sock *mptcp_userspace_pm_get_sock(const struct genl_info *info)
 {
 	struct mptcp_sock *msk;
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index XXXXXXX..XXXXXXX 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -XXX,XX +XXX,XX @@ void mptcp_pm_param_set_contexts(struct mptcp_pm_param *param,
 				 const struct mptcp_addr_info *addr);
 int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc);
 bool mptcp_pm_is_backup(struct mptcp_sock *msk, struct sock_common *skc);
-bool mptcp_pm_nl_is_backup(struct mptcp_sock *msk, struct mptcp_addr_info *skc);
-bool mptcp_userspace_pm_is_backup(struct mptcp_sock *msk, struct mptcp_addr_info *skc);
 int mptcp_pm_nl_dump_addr(struct sk_buff *msg,
 			  struct netlink_callback *cb);
 int mptcp_userspace_pm_dump_addr(struct sk_buff *msg,
-- 
2.43.0