[MPTCP] [MPTCP][PATCH v2 mptcp-next 1/3] mptcp: create subflow or signal addr for newly added address

[MPTCP] [MPTCP][PATCH v2 mptcp-next 1/3] mptcp: create subflow or signal addr for newly added address

[Geliang Tang]

[-- Attachment #1: Type: text/plain, Size: 3808 bytes --]

Currently, when a new MPTCP endpoint is added, the existing MPTCP sockets
are not affected.

This patch implemented a new function mptcp_nl_add_subflow_or_signal_addr,
invoked when an address is added from PM netlink. This function traversed
the MPTCP sockets list and invoked mptcp_pm_create_subflow_or_signal_addr
to try to create a subflow or signal an address for the newly added
address, if local constraint allows that.

Signed-off-by: Geliang Tang <geliangtang(a)gmail.com>
---
 net/mptcp/pm_netlink.c | 43 ++++++++++++++++++++++++++++++++++++------
 1 file changed, 37 insertions(+), 6 deletions(-)

diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index 9c688023f494..96993ded911c 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -316,17 +316,21 @@ static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
 	struct mptcp_addr_info remote = { 0 };
 	struct sock *sk = (struct sock *)msk;
 	struct mptcp_pm_addr_entry *local;
+	unsigned int add_addr_signal_max;
+	unsigned int local_addr_max;
 	struct pm_nl_pernet *pernet;
 
 	pernet = net_generic(sock_net(sk), pm_nl_pernet_id);
+	add_addr_signal_max = READ_ONCE(pernet->add_addr_signal_max);
+	local_addr_max = READ_ONCE(pernet->local_addr_max);
 
 	pr_debug("local %d:%d signal %d:%d subflows %d:%d\n",
-		 msk->pm.local_addr_used, msk->pm.local_addr_max,
-		 msk->pm.add_addr_signaled, msk->pm.add_addr_signal_max,
+		 msk->pm.local_addr_used, local_addr_max,
+		 msk->pm.add_addr_signaled, add_addr_signal_max,
 		 msk->pm.subflows, msk->pm.subflows_max);
 
 	/* check first for announce */
-	if (msk->pm.add_addr_signaled < msk->pm.add_addr_signal_max) {
+	if (msk->pm.add_addr_signaled < add_addr_signal_max) {
 		local = select_signal_address(pernet,
 					      msk->pm.add_addr_signaled);
 
@@ -338,14 +342,14 @@ static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
 			}
 		} else {
 			/* pick failed, avoid fourther attempts later */
-			msk->pm.local_addr_used = msk->pm.add_addr_signal_max;
+			msk->pm.local_addr_used = add_addr_signal_max;
 		}
 
 		check_work_pending(msk);
 	}
 
 	/* check if should create a new subflow */
-	if (msk->pm.local_addr_used < msk->pm.local_addr_max &&
+	if (msk->pm.local_addr_used < local_addr_max &&
 	    msk->pm.subflows < msk->pm.subflows_max) {
 		remote_address((struct sock_common *)sk, &remote);
 
@@ -361,7 +365,7 @@ static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
 		}
 
 		/* lookup failed, avoid fourther attempts later */
-		msk->pm.local_addr_used = msk->pm.local_addr_max;
+		msk->pm.local_addr_used = local_addr_max;
 		check_work_pending(msk);
 	}
 }
@@ -793,6 +797,31 @@ static struct pm_nl_pernet *genl_info_pm_nl(struct genl_info *info)
 	return net_generic(genl_info_net(info), pm_nl_pernet_id);
 }
 
+static int mptcp_nl_add_subflow_or_signal_addr(struct net *net)
+{
+	struct mptcp_sock *msk;
+	long s_slot = 0, s_num = 0;
+
+	while ((msk = mptcp_token_iter_next(net, &s_slot, &s_num)) != NULL) {
+		struct sock *sk = (struct sock *)msk;
+
+		if (!READ_ONCE(msk->fully_established))
+			goto next;
+
+		lock_sock(sk);
+		spin_lock_bh(&msk->pm.lock);
+		mptcp_pm_create_subflow_or_signal_addr(msk);
+		spin_unlock_bh(&msk->pm.lock);
+		release_sock(sk);
+
+next:
+		sock_put(sk);
+		cond_resched();
+	}
+
+	return 0;
+}
+
 static int mptcp_nl_cmd_add_addr(struct sk_buff *skb, struct genl_info *info)
 {
 	struct nlattr *attr = info->attrs[MPTCP_PM_ATTR_ADDR];
@@ -818,6 +847,8 @@ static int mptcp_nl_cmd_add_addr(struct sk_buff *skb, struct genl_info *info)
 		return ret;
 	}
 
+	mptcp_nl_add_subflow_or_signal_addr(sock_net(skb->sk));
+
 	return 0;
 }
 
-- 
2.29.2