mptcp: read attributes of addr entries managed by userspace PMs

This change introduces a parallel path in the kernel for retrieving
the local id, flags, if_index for an addr entry in the context of
an MPTCP connection that's being managed by a userspace PM. The
userspace and in-kernel PM modes deviate in their procedures for
obtaining this information.
Acked-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Kishen Maloor <kishen.maloor@intel.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/mptcp/pm_netlink.c

@@ -1033,6 +1033,9 @@ int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct sock_common *skc)
 	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();
@@ -1297,15 +1300,23 @@ static int mptcp_nl_cmd_add_addr(struct sk_buff *skb, struct genl_info *info)
 	return 0;
 }
 
-int mptcp_pm_get_flags_and_ifindex_by_id(struct net *net, unsigned int id,
+int mptcp_pm_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) {

net/mptcp/pm_userspace.c

@@ -76,3 +76,46 @@ int mptcp_userspace_pm_append_new_local_addr(struct mptcp_sock *msk,
 	spin_unlock_bh(&msk->pm.lock);
 	return ret;
 }
+
+int mptcp_userspace_pm_get_flags_and_ifindex_by_id(struct mptcp_sock *msk,
+						   unsigned int id,
+						   u8 *flags, int *ifindex)
+{
+	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) {
+			match = entry;
+			break;
+		}
+	}
+	spin_unlock_bh(&msk->pm.lock);
+	if (match) {
+		*flags = match->flags;
+		*ifindex = match->ifindex;
+	}
+
+	return 0;
+}
+
+int mptcp_userspace_pm_get_local_id(struct mptcp_sock *msk,
+				    struct mptcp_addr_info *skc)
+{
+	struct mptcp_pm_addr_entry new_entry;
+	__be16 msk_sport =  ((struct inet_sock *)
+			     inet_sk((struct sock *)msk))->inet_sport;
+
+	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;
+
+	return mptcp_userspace_pm_append_new_local_addr(msk, &new_entry);
+}

net/mptcp/protocol.h

@@ -783,7 +783,11 @@ mptcp_pm_del_add_timer(struct mptcp_sock *msk,
 struct mptcp_pm_add_entry *
 mptcp_lookup_anno_list_by_saddr(const struct mptcp_sock *msk,
 				const struct mptcp_addr_info *addr);
-int mptcp_pm_get_flags_and_ifindex_by_id(struct net *net, unsigned int id,
+int mptcp_pm_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_announce_addr(struct mptcp_sock *msk,
@@ -862,6 +866,7 @@ 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_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);

net/mptcp/subflow.c

@@ -1468,7 +1468,7 @@ int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc,
 	if (local_id)
 		subflow_set_local_id(subflow, local_id);
 
-	mptcp_pm_get_flags_and_ifindex_by_id(sock_net(sk), local_id,
+	mptcp_pm_get_flags_and_ifindex_by_id(msk, local_id,
 					     &flags, &ifindex);
 	subflow->remote_key = msk->remote_key;
 	subflow->local_key = msk->local_key;