Merge branch 'mptcp-unify-pm-interfaces'

Matthieu Baerts says:

====================
mptcp: unify PM interfaces

These patches from Geliang better isolate the two MPTCP path-managers by
avoiding calling userspace PM functions from the in-kernel PM. Instead,
new functions declared in pm.c directly dispatch to the right PM.

In addition to have a clearer code, this also avoids a bit of duplicated
checks.

This is a refactoring, there is no behaviour change intended here.
====================

Link: https://lore.kernel.org/r/20230608-upstream-net-next-20230608-mptcp-unify-pm-interfaces-v1-0-b301717c9ff5@tessares.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

4 files changed, 103 insertions, 82 deletions

diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
index 92d540e527a2..7dbbad1e4f55 100644
--- a/net/mptcp/pm.c
+++ b/net/mptcp/pm.c
@@ -415,7 +415,46 @@ out_unlock:
 
 int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc)
 {
-	return mptcp_pm_nl_get_local_id(msk, skc);
+	struct mptcp_addr_info skc_local;
+	struct mptcp_addr_info msk_local;
+
+	if (WARN_ON_ONCE(!msk))
+		return -1;
+
+	/* 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))
+		return 0;
+
+	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);
+}
+
+int mptcp_pm_get_flags_and_ifindex_by_id(struct mptcp_sock *msk, unsigned int id,
+					 u8 *flags, int *ifindex)
+{
+	*flags = 0;
+	*ifindex = 0;
+
+	if (!id)
+		return 0;
+
+	if (mptcp_pm_is_userspace(msk))
+		return mptcp_userspace_pm_get_flags_and_ifindex_by_id(msk, id, flags, ifindex);
+	return mptcp_pm_nl_get_flags_and_ifindex_by_id(msk, id, flags, ifindex);
+}
+
+int mptcp_pm_set_flags(struct net *net, struct nlattr *token,
+		       struct mptcp_pm_addr_entry *loc,
+		       struct mptcp_pm_addr_entry *rem, u8 bkup)
+{
+	if (token)
+		return mptcp_userspace_pm_set_flags(net, token, loc, rem, bkup);
+	return mptcp_pm_nl_set_flags(net, loc, bkup);
 }
 
 void mptcp_pm_subflow_chk_stale(const struct mptcp_sock *msk, struct sock *ssk)
diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index 59f8f3124855..a12a87b780f6 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -86,8 +86,7 @@ bool mptcp_addresses_equal(const struct mptcp_addr_info *a,
 	return a->port == b->port;
 }
 
-static void local_address(const struct sock_common *skc,
-			  struct mptcp_addr_info *addr)
+void mptcp_local_address(const struct sock_common *skc, struct mptcp_addr_info *addr)
 {
 	addr->family = skc->skc_family;
 	addr->port = htons(skc->skc_num);
@@ -122,7 +121,7 @@ static bool lookup_subflow_by_saddr(const struct list_head *list,
 	list_for_each_entry(subflow, list, node) {
 		skc = (struct sock_common *)mptcp_subflow_tcp_sock(subflow);
 
-		local_address(skc, &cur);
+		mptcp_local_address(skc, &cur);
 		if (mptcp_addresses_equal(&cur, saddr, saddr->port))
 			return true;
 	}
@@ -263,7 +262,7 @@ bool mptcp_pm_sport_in_anno_list(struct mptcp_sock *msk, const struct sock *sk)
 	struct mptcp_addr_info saddr;
 	bool ret = false;
 
-	local_address((struct sock_common *)sk, &saddr);
+	mptcp_local_address((struct sock_common *)sk, &saddr);
 
 	spin_lock_bh(&msk->pm.lock);
 	list_for_each_entry(entry, &msk->pm.anno_list, list) {
@@ -541,7 +540,7 @@ static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
 		struct mptcp_addr_info mpc_addr;
 		bool backup = false;
 
-		local_address((struct sock_common *)msk->first, &mpc_addr);
+		mptcp_local_address((struct sock_common *)msk->first, &mpc_addr);
 		rcu_read_lock();
 		entry = __lookup_addr(pernet, &mpc_addr, false);
 		if (entry) {
@@ -752,7 +751,7 @@ int mptcp_pm_nl_mp_prio_send_ack(struct mptcp_sock *msk,
 		struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
 		struct mptcp_addr_info local, remote;
 
-		local_address((struct sock_common *)ssk, &local);
+		mptcp_local_address((struct sock_common *)ssk, &local);
 		if (!mptcp_addresses_equal(&local, addr, addr->port))
 			continue;
 
@@ -1056,33 +1055,17 @@ static int mptcp_pm_nl_create_listen_socket(struct sock *sk,
 	return 0;
 }
 
-int mptcp_pm_nl_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)
 {
 	struct mptcp_pm_addr_entry *entry;
-	struct mptcp_addr_info skc_local;
-	struct mptcp_addr_info msk_local;
 	struct pm_nl_pernet *pernet;
 	int ret = -1;
 
-	if (WARN_ON_ONCE(!msk))
-		return -1;
-
-	/* The 0 ID mapping is defined by the first subflow, copied into the msk
-	 * addr
-	 */
-	local_address((struct sock_common *)msk, &msk_local);
-	local_address((struct sock_common *)skc, &skc_local);
-	if (mptcp_addresses_equal(&msk_local, &skc_local, false))
-		return 0;
-
-	if (mptcp_pm_is_userspace(msk))
-		return mptcp_userspace_pm_get_local_id(msk, &skc_local);
-
 	pernet = pm_nl_get_pernet_from_msk(msk);
 
 	rcu_read_lock();
 	list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) {
-		if (mptcp_addresses_equal(&entry->addr, &skc_local, entry->addr.port)) {
+		if (mptcp_addresses_equal(&entry->addr, skc, entry->addr.port)) {
 			ret = entry->addr.id;
 			break;
 		}
@@ -1096,7 +1079,7 @@ int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct sock_common *skc)
 	if (!entry)
 		return -ENOMEM;
 
-	entry->addr = skc_local;
+	entry->addr = *skc;
 	entry->addr.id = 0;
 	entry->addr.port = 0;
 	entry->ifindex = 0;
@@ -1373,31 +1356,20 @@ out_free:
 	return ret;
 }
 
-int mptcp_pm_get_flags_and_ifindex_by_id(struct mptcp_sock *msk, unsigned int id,
-					 u8 *flags, int *ifindex)
+int mptcp_pm_nl_get_flags_and_ifindex_by_id(struct mptcp_sock *msk, unsigned int id,
+					    u8 *flags, int *ifindex)
 {
 	struct mptcp_pm_addr_entry *entry;
 	struct sock *sk = (struct sock *)msk;
 	struct net *net = sock_net(sk);
 
-	*flags = 0;
-	*ifindex = 0;
-
-	if (id) {
-		if (mptcp_pm_is_userspace(msk))
-			return mptcp_userspace_pm_get_flags_and_ifindex_by_id(msk,
-									      id,
-									      flags,
-									      ifindex);
-
-		rcu_read_lock();
-		entry = __lookup_addr_by_id(pm_nl_get_pernet(net), id);
-		if (entry) {
-			*flags = entry->flags;
-			*ifindex = entry->ifindex;
-		}
-		rcu_read_unlock();
+	rcu_read_lock();
+	entry = __lookup_addr_by_id(pm_nl_get_pernet(net), id);
+	if (entry) {
+		*flags = entry->flags;
+		*ifindex = entry->ifindex;
 	}
+	rcu_read_unlock();
 
 	return 0;
 }
@@ -1491,7 +1463,7 @@ static int mptcp_nl_remove_id_zero_address(struct net *net,
 		if (list_empty(&msk->conn_list) || mptcp_pm_is_userspace(msk))
 			goto next;
 
-		local_address((struct sock_common *)msk, &msk_local);
+		mptcp_local_address((struct sock_common *)msk, &msk_local);
 		if (!mptcp_addresses_equal(&msk_local, addr, addr->port))
 			goto next;
 
@@ -1910,18 +1882,50 @@ next:
 	return ret;
 }
 
+int mptcp_pm_nl_set_flags(struct net *net, struct mptcp_pm_addr_entry *addr, u8 bkup)
+{
+	struct pm_nl_pernet *pernet = pm_nl_get_pernet(net);
+	u8 changed, mask = MPTCP_PM_ADDR_FLAG_BACKUP |
+			   MPTCP_PM_ADDR_FLAG_FULLMESH;
+	struct mptcp_pm_addr_entry *entry;
+	u8 lookup_by_id = 0;
+
+	if (addr->addr.family == AF_UNSPEC) {
+		lookup_by_id = 1;
+		if (!addr->addr.id)
+			return -EOPNOTSUPP;
+	}
+
+	spin_lock_bh(&pernet->lock);
+	entry = __lookup_addr(pernet, &addr->addr, lookup_by_id);
+	if (!entry) {
+		spin_unlock_bh(&pernet->lock);
+		return -EINVAL;
+	}
+	if ((addr->flags & MPTCP_PM_ADDR_FLAG_FULLMESH) &&
+	    (entry->flags & MPTCP_PM_ADDR_FLAG_SIGNAL)) {
+		spin_unlock_bh(&pernet->lock);
+		return -EINVAL;
+	}
+
+	changed = (addr->flags ^ entry->flags) & mask;
+	entry->flags = (entry->flags & ~mask) | (addr->flags & mask);
+	*addr = *entry;
+	spin_unlock_bh(&pernet->lock);
+
+	mptcp_nl_set_flags(net, &addr->addr, bkup, changed);
+	return 0;
+}
+
 static int mptcp_nl_cmd_set_flags(struct sk_buff *skb, struct genl_info *info)
 {
-	struct mptcp_pm_addr_entry addr = { .addr = { .family = AF_UNSPEC }, }, *entry;
 	struct mptcp_pm_addr_entry remote = { .addr = { .family = AF_UNSPEC }, };
+	struct mptcp_pm_addr_entry addr = { .addr = { .family = AF_UNSPEC }, };
 	struct nlattr *attr_rem = info->attrs[MPTCP_PM_ATTR_ADDR_REMOTE];
 	struct nlattr *token = info->attrs[MPTCP_PM_ATTR_TOKEN];
 	struct nlattr *attr = info->attrs[MPTCP_PM_ATTR_ADDR];
-	struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
-	u8 changed, mask = MPTCP_PM_ADDR_FLAG_BACKUP |
-			   MPTCP_PM_ADDR_FLAG_FULLMESH;
 	struct net *net = sock_net(skb->sk);
-	u8 bkup = 0, lookup_by_id = 0;
+	u8 bkup = 0;
 	int ret;
 
 	ret = mptcp_pm_parse_entry(attr, info, false, &addr);
@@ -1936,34 +1940,8 @@ static int mptcp_nl_cmd_set_flags(struct sk_buff *skb, struct genl_info *info)
 
 	if (addr.flags & MPTCP_PM_ADDR_FLAG_BACKUP)
 		bkup = 1;
-	if (addr.addr.family == AF_UNSPEC) {
-		lookup_by_id = 1;
-		if (!addr.addr.id)
-			return -EOPNOTSUPP;
-	}
-
-	if (token)
-		return mptcp_userspace_pm_set_flags(net, token, &addr, &remote, bkup);
 
-	spin_lock_bh(&pernet->lock);
-	entry = __lookup_addr(pernet, &addr.addr, lookup_by_id);
-	if (!entry) {
-		spin_unlock_bh(&pernet->lock);
-		return -EINVAL;
-	}
-	if ((addr.flags & MPTCP_PM_ADDR_FLAG_FULLMESH) &&
-	    (entry->flags & MPTCP_PM_ADDR_FLAG_SIGNAL)) {
-		spin_unlock_bh(&pernet->lock);
-		return -EINVAL;
-	}
-
-	changed = (addr.flags ^ entry->flags) & mask;
-	entry->flags = (entry->flags & ~mask) | (addr.flags & mask);
-	addr = *entry;
-	spin_unlock_bh(&pernet->lock);
-
-	mptcp_nl_set_flags(net, &addr.addr, bkup, changed);
-	return 0;
+	return mptcp_pm_set_flags(net, token, &addr, &remote, bkup);
 }
 
 static void mptcp_nl_mcast_send(struct net *net, struct sk_buff *nlskb, gfp_t gfp)
diff --git a/net/mptcp/pm_userspace.c b/net/mptcp/pm_userspace.c
index b06aa58dfcf2..47a883a16c11 100644
--- a/net/mptcp/pm_userspace.c
+++ b/net/mptcp/pm_userspace.c
@@ -111,9 +111,6 @@ int mptcp_userspace_pm_get_flags_and_ifindex_by_id(struct mptcp_sock *msk,
 {
 	struct mptcp_pm_addr_entry *entry, *match = NULL;
 
-	*flags = 0;
-	*ifindex = 0;
-
 	spin_lock_bh(&msk->pm.lock);
 	list_for_each_entry(entry, &msk->pm.userspace_pm_local_addr_list, list) {
 		if (id == entry->addr.id) {
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 70c957bc56a8..47b46602870e 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -638,6 +638,7 @@ void mptcp_set_owner_r(struct sk_buff *skb, struct sock *sk);
 
 bool mptcp_addresses_equal(const struct mptcp_addr_info *a,
 			   const struct mptcp_addr_info *b, bool use_port);
+void mptcp_local_address(const struct sock_common *skc, struct mptcp_addr_info *addr);
 
 /* called with sk socket lock held */
 int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc,
@@ -821,9 +822,15 @@ mptcp_lookup_anno_list_by_saddr(const struct mptcp_sock *msk,
 int mptcp_pm_get_flags_and_ifindex_by_id(struct mptcp_sock *msk,
 					 unsigned int id,
 					 u8 *flags, int *ifindex);
+int mptcp_pm_nl_get_flags_and_ifindex_by_id(struct mptcp_sock *msk, unsigned int id,
+					    u8 *flags, int *ifindex);
 int mptcp_userspace_pm_get_flags_and_ifindex_by_id(struct mptcp_sock *msk,
 						   unsigned int id,
 						   u8 *flags, int *ifindex);
+int mptcp_pm_set_flags(struct net *net, struct nlattr *token,
+		       struct mptcp_pm_addr_entry *loc,
+		       struct mptcp_pm_addr_entry *rem, u8 bkup);
+int mptcp_pm_nl_set_flags(struct net *net, struct mptcp_pm_addr_entry *addr, u8 bkup);
 int mptcp_userspace_pm_set_flags(struct net *net, struct nlattr *token,
 				 struct mptcp_pm_addr_entry *loc,
 				 struct mptcp_pm_addr_entry *rem, u8 bkup);
@@ -916,13 +923,13 @@ 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);
 
 void __init mptcp_pm_nl_init(void);
 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);
-int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct sock_common *skc);
 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);
 unsigned int mptcp_pm_get_subflows_max(const struct mptcp_sock *msk);