mptcp: create the listening socket for new port

This patch creates a listening socket when an address with a port-number
is added by PM netlink. Then binds the new port to the socket, and
listens for new connections.

When the address is removed or the addresses are flushed by PM netlink,
release the listening socket.

Signed-off-by: Geliang Tang <geliangtang@gmail.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 94 insertions, 2 deletions

diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index 5d87e475c751..b71701a743a4 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -26,6 +26,7 @@ struct mptcp_pm_addr_entry {
 	struct list_head	list;
 	struct mptcp_addr_info	addr;
 	struct rcu_head		rcu;
+	struct socket		*lsk;
 };
 
 struct mptcp_pm_add_entry {
@@ -678,6 +679,53 @@ out:
 	return ret;
 }
 
+static int mptcp_pm_nl_create_listen_socket(struct sock *sk,
+					    struct mptcp_pm_addr_entry *entry)
+{
+	struct sockaddr_storage addr;
+	struct mptcp_sock *msk;
+	struct socket *ssock;
+	int backlog = 1024;
+	int err;
+
+	err = sock_create_kern(sock_net(sk), entry->addr.family,
+			       SOCK_STREAM, IPPROTO_MPTCP, &entry->lsk);
+	if (err)
+		return err;
+
+	msk = mptcp_sk(entry->lsk->sk);
+	if (!msk) {
+		err = -EINVAL;
+		goto out;
+	}
+
+	ssock = __mptcp_nmpc_socket(msk);
+	if (!ssock) {
+		err = -EINVAL;
+		goto out;
+	}
+
+	mptcp_info2sockaddr(&entry->addr, &addr, entry->addr.family);
+	err = kernel_bind(ssock, (struct sockaddr *)&addr,
+			  sizeof(struct sockaddr_in));
+	if (err) {
+		pr_warn("kernel_bind error, err=%d", err);
+		goto out;
+	}
+
+	err = kernel_listen(ssock, backlog);
+	if (err) {
+		pr_warn("kernel_listen error, err=%d", err);
+		goto out;
+	}
+
+	return 0;
+
+out:
+	sock_release(entry->lsk);
+	return err;
+}
+
 int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct sock_common *skc)
 {
 	struct mptcp_pm_addr_entry *entry;
@@ -722,6 +770,8 @@ int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct sock_common *skc)
 	entry->addr.ifindex = 0;
 	entry->addr.flags = 0;
 	entry->addr.id = 0;
+	entry->addr.port = 0;
+	entry->lsk = NULL;
 	ret = mptcp_pm_nl_append_new_local_addr(pernet, entry);
 	if (ret < 0)
 		kfree(entry);
@@ -891,9 +941,19 @@ static int mptcp_nl_cmd_add_addr(struct sk_buff *skb, struct genl_info *info)
 	}
 
 	*entry = addr;
+	if (entry->addr.port) {
+		ret = mptcp_pm_nl_create_listen_socket(skb->sk, entry);
+		if (ret) {
+			GENL_SET_ERR_MSG(info, "create listen socket error");
+			kfree(entry);
+			return ret;
+		}
+	}
 	ret = mptcp_pm_nl_append_new_local_addr(pernet, entry);
 	if (ret < 0) {
 		GENL_SET_ERR_MSG(info, "too many addresses or duplicate one");
+		if (entry->lsk)
+			sock_release(entry->lsk);
 		kfree(entry);
 		return ret;
 	}
@@ -977,6 +1037,38 @@ next:
 	return 0;
 }
 
+struct addr_entry_release_work {
+	struct rcu_work	rwork;
+	struct mptcp_pm_addr_entry *entry;
+};
+
+static void mptcp_pm_release_addr_entry(struct work_struct *work)
+{
+	struct addr_entry_release_work *w;
+	struct mptcp_pm_addr_entry *entry;
+
+	w = container_of(to_rcu_work(work), struct addr_entry_release_work, rwork);
+	entry = w->entry;
+	if (entry) {
+		if (entry->lsk)
+			sock_release(entry->lsk);
+		kfree(entry);
+	}
+	kfree(w);
+}
+
+static void mptcp_pm_free_addr_entry(struct mptcp_pm_addr_entry *entry)
+{
+	struct addr_entry_release_work *w;
+
+	w = kmalloc(sizeof(*w), GFP_ATOMIC);
+	if (w) {
+		INIT_RCU_WORK(&w->rwork, mptcp_pm_release_addr_entry);
+		w->entry = entry;
+		queue_rcu_work(system_wq, &w->rwork);
+	}
+}
+
 static int mptcp_nl_cmd_del_addr(struct sk_buff *skb, struct genl_info *info)
 {
 	struct nlattr *attr = info->attrs[MPTCP_PM_ATTR_ADDR];
@@ -1011,7 +1103,7 @@ static int mptcp_nl_cmd_del_addr(struct sk_buff *skb, struct genl_info *info)
 	spin_unlock_bh(&pernet->lock);
 
 	mptcp_nl_remove_subflow_and_signal_addr(sock_net(skb->sk), &entry->addr);
-	kfree_rcu(entry, rcu);
+	mptcp_pm_free_addr_entry(entry);
 
 	return ret;
 }
@@ -1025,7 +1117,7 @@ static void __flush_addrs(struct net *net, struct list_head *list)
 				 struct mptcp_pm_addr_entry, list);
 		mptcp_nl_remove_subflow_and_signal_addr(net, &cur->addr);
 		list_del_rcu(&cur->list);
-		kfree_rcu(cur, rcu);
+		mptcp_pm_free_addr_entry(cur);
 	}
 }