[MPTCP][PATCH mptcp-next 3/9] mptcp: add fullmesh worker

[Geliang Tang <geliangtang@gmail.com>]

This patch implemented the fullmesh worker named mptcp_pm_fm_work. In
it, deal with the PM established status and invoke the function
mptcp_pm_fm_create_subflow to create the subflow.

Signed-off-by: Geliang Tang <geliangtang@gmail.com>
---
 net/mptcp/pm_fullmesh.c | 95 +++++++++++++++++++++++++++++++++++++++++
 net/mptcp/pm_netlink.c  |  8 ++--
 net/mptcp/protocol.c    |  2 +
 net/mptcp/protocol.h    |  5 +++
 4 files changed, 106 insertions(+), 4 deletions(-)

diff --git a/net/mptcp/pm_fullmesh.c b/net/mptcp/pm_fullmesh.c
index 4cdcb572b125..b27f13a031e3 100644
--- a/net/mptcp/pm_fullmesh.c
+++ b/net/mptcp/pm_fullmesh.c
@@ -26,6 +26,101 @@ struct pm_fm_pernet {
 	unsigned int		next_id;
 };
 
+static struct mptcp_fm_addr_entry *
+select_local_address(const struct pm_fm_pernet *pernet,
+		     struct mptcp_sock *msk)
+{
+	struct mptcp_fm_addr_entry *entry, *ret = NULL;
+	struct sock *sk = (struct sock *)msk;
+
+	msk_owned_by_me(msk);
+
+	rcu_read_lock();
+	__mptcp_flush_join_list(msk);
+	list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) {
+		if (entry->addr.family != sk->sk_family)
+				continue;
+
+		if (!lookup_subflow_by_saddr(&msk->conn_list, &entry->addr)) {
+			ret = entry;
+			break;
+		}
+	}
+	rcu_read_unlock();
+	return ret;
+}
+
+static void check_work_pending(struct mptcp_sock *msk)
+{
+	if (msk->pm.local_addr_used == MPTCP_PM_FM_MAX_ADDR ||
+	    msk->pm.subflows == MPTCP_PM_FM_MAX_ADDR)
+		WRITE_ONCE(msk->pm.work_pending, false);
+}
+
+static void mptcp_pm_fm_create_subflow(struct mptcp_sock *msk)
+{
+	unsigned int local_addr_max = MPTCP_PM_FM_MAX_ADDR;
+	unsigned int subflows_max = MPTCP_PM_FM_MAX_ADDR;
+	struct sock *sk = (struct sock *)msk;
+	struct mptcp_fm_addr_entry *local;
+	struct pm_fm_pernet *pernet;
+
+	pernet = net_generic(sock_net(sk), pm_fm_pernet_id);
+
+	if (msk->pm.local_addr_used < local_addr_max &&
+	    msk->pm.subflows < subflows_max &&
+	    !READ_ONCE(msk->pm.remote_deny_join_id0)) {
+		local = select_local_address(pernet, msk);
+		if (local) {
+			struct mptcp_addr_info remote = { 0 };
+
+			msk->pm.local_addr_used++;
+			msk->pm.subflows++;
+			check_work_pending(msk);
+			remote_address((struct sock_common *)sk, &remote);
+			spin_unlock_bh(&msk->pm.lock);
+			__mptcp_subflow_connect(sk, &local->addr, &remote, 0, 0);
+			spin_lock_bh(&msk->pm.lock);
+			return;
+		}
+
+		/* lookup failed, avoid fourther attempts later */
+		msk->pm.local_addr_used = local_addr_max;
+		check_work_pending(msk);
+	}
+}
+
+static void mptcp_pm_fm_fully_established(struct mptcp_sock *msk)
+{
+	mptcp_pm_fm_create_subflow(msk);
+}
+
+static void mptcp_pm_fm_subflow_established(struct mptcp_sock *msk)
+{
+	mptcp_pm_fm_create_subflow(msk);
+}
+
+void mptcp_pm_fm_work(struct mptcp_sock *msk)
+{
+	struct mptcp_pm_data *pm = &msk->pm;
+
+	msk_owned_by_me(msk);
+
+	spin_lock_bh(&msk->pm.lock);
+
+	pr_debug("msk=%p status=%x", msk, pm->status);
+	if (pm->status & BIT(MPTCP_PM_ESTABLISHED)) {
+		pm->status &= ~BIT(MPTCP_PM_ESTABLISHED);
+		mptcp_pm_fm_fully_established(msk);
+	}
+	if (pm->status & BIT(MPTCP_PM_SUBFLOW_ESTABLISHED)) {
+		pm->status &= ~BIT(MPTCP_PM_SUBFLOW_ESTABLISHED);
+		mptcp_pm_fm_subflow_established(msk);
+	}
+
+	spin_unlock_bh(&msk->pm.lock);
+}
+
 void mptcp_pm_fm_data_init(struct mptcp_sock *msk)
 {
 	struct mptcp_pm_data *pm = &msk->pm;
diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index 56263c2c4014..d050dbd89e24 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -108,8 +108,8 @@ static void local_address(const struct sock_common *skc,
 #endif
 }
 
-static void remote_address(const struct sock_common *skc,
-			   struct mptcp_addr_info *addr)
+void remote_address(const struct sock_common *skc,
+		    struct mptcp_addr_info *addr)
 {
 	addr->family = skc->skc_family;
 	addr->port = skc->skc_dport;
@@ -121,8 +121,8 @@ static void remote_address(const struct sock_common *skc,
 #endif
 }
 
-static bool lookup_subflow_by_saddr(const struct list_head *list,
-				    struct mptcp_addr_info *saddr)
+bool lookup_subflow_by_saddr(const struct list_head *list,
+			     struct mptcp_addr_info *saddr)
 {
 	struct mptcp_subflow_context *subflow;
 	struct mptcp_addr_info cur;
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 938690f87b8f..2af54eb5fe44 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -2343,6 +2343,8 @@ static void mptcp_worker(struct work_struct *work)
 		pm = mptcp_get_path_manager(net);
 		if (!strcmp(pm, "netlink"))
 			mptcp_pm_nl_work(msk);
+		else if (!strcmp(pm, "fullmesh"))
+			mptcp_pm_fm_work(msk);
 	}
 
 	if (test_and_clear_bit(MPTCP_WORK_EOF, &msk->flags))
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 3de2a298e8d9..99c23a1887d8 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -717,6 +717,10 @@ mptcp_pm_del_add_timer(struct mptcp_sock *msk,
 struct mptcp_pm_add_entry *
 mptcp_lookup_anno_list_by_saddr(struct mptcp_sock *msk,
 				struct mptcp_addr_info *addr);
+bool lookup_subflow_by_saddr(const struct list_head *list,
+			     struct mptcp_addr_info *saddr);
+void remote_address(const struct sock_common *skc,
+		    struct mptcp_addr_info *addr);
 
 int mptcp_pm_announce_addr(struct mptcp_sock *msk,
 			   const struct mptcp_addr_info *addr,
@@ -794,6 +798,7 @@ unsigned int mptcp_pm_get_add_addr_accept_max(struct mptcp_sock *msk);
 unsigned int mptcp_pm_get_subflows_max(struct mptcp_sock *msk);
 unsigned int mptcp_pm_get_local_addr_max(struct mptcp_sock *msk);
 void __init mptcp_pm_fm_init(void);
+void mptcp_pm_fm_work(struct mptcp_sock *msk);
 void mptcp_pm_fm_data_init(struct mptcp_sock *msk);
 
 void mptcp_sockopt_sync(struct mptcp_sock *msk, struct sock *ssk);
-- 
2.31.1