mptcp: set fullmesh flag in pm_netlink

This patch added the fullmesh flag setting support in pm_netlink.

If the fullmesh flag of the address is changed, remove all the related
subflows, update the fullmesh flag and create subflows again.
Acked-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Geliang Tang <geliang.tang@suse.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

@@ -1728,9 +1728,20 @@ mptcp_nl_cmd_get_limits(struct sk_buff *skb, struct genl_info *info)
 	return -EMSGSIZE;
 }
 
-static int mptcp_nl_addr_backup(struct net *net,
+static void mptcp_pm_nl_fullmesh(struct mptcp_sock *msk,
+				 struct mptcp_addr_info *addr)
+{
+	struct mptcp_rm_list list = { .nr = 0 };
+
+	list.ids[list.nr++] = addr->id;
+
+	mptcp_pm_nl_rm_subflow_received(msk, &list);
+	mptcp_pm_create_subflow_or_signal_addr(msk);
+}
+
+static int mptcp_nl_set_flags(struct net *net,
 			      struct mptcp_addr_info *addr,
-				u8 bkup)
+			      u8 bkup, u8 changed)
 {
 	long s_slot = 0, s_num = 0;
 	struct mptcp_sock *msk;
@@ -1744,7 +1755,10 @@ static int mptcp_nl_addr_backup(struct net *net,
 
 		lock_sock(sk);
 		spin_lock_bh(&msk->pm.lock);
+		if (changed & MPTCP_PM_ADDR_FLAG_BACKUP)
 			ret = mptcp_pm_nl_mp_prio_send_ack(msk, addr, bkup);
+		if (changed & MPTCP_PM_ADDR_FLAG_FULLMESH)
+			mptcp_pm_nl_fullmesh(msk, addr);
 		spin_unlock_bh(&msk->pm.lock);
 		release_sock(sk);
 
@@ -1761,6 +1775,8 @@ 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 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;
 	int ret;
@@ -1783,15 +1799,18 @@ static int mptcp_nl_cmd_set_flags(struct sk_buff *skb, struct genl_info *info)
 		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;
+	}
 
-	if (bkup)
-		entry->flags |= MPTCP_PM_ADDR_FLAG_BACKUP;
-	else
-		entry->flags &= ~MPTCP_PM_ADDR_FLAG_BACKUP;
+	changed = (addr.flags ^ entry->flags) & mask;
+	entry->flags = (entry->flags & ~mask) | (addr.flags & mask);
 	addr = *entry;
 	spin_unlock_bh(&pernet->lock);
 
-	mptcp_nl_addr_backup(net, &addr.addr, bkup);
+	mptcp_nl_set_flags(net, &addr.addr, bkup, changed);
 	return 0;
 }