l2tpv3: T1594: Fix timeout before set l2tpv3 interface

In some cases, we need to wait until local address is assigned.
And only then l2tpv3 tunnel can be configured.
For example when ipv6 address is in "tentative" state
or we wait for some routing daemon/route for a remote address.

1 files changed, 23 insertions, 1 deletions

diff --git a/python/vyos/ifconfig/l2tpv3.py b/python/vyos/ifconfig/l2tpv3.py
index 7ff0fdd0e..fcd1fbf81 100644
--- a/python/vyos/ifconfig/l2tpv3.py
+++ b/python/vyos/ifconfig/l2tpv3.py
@@ -13,8 +13,28 @@
 # You should have received a copy of the GNU Lesser General Public
 # License along with this library.  If not, see <http://www.gnu.org/licenses/>.
 
+from time import sleep
+from time import time
+from vyos.util import run
 from vyos.ifconfig.interface import Interface
 
+def wait_for_add_l2tpv3(timeout=10, sleep_interval=1, cmd=None):
+    '''
+    In some cases, we need to wait until local address is assigned.
+    And only then can the l2tpv3 tunnel be configured.
+    For example when ipv6 address in tentative state
+    or we wait for some routing daemon for remote address.
+    '''
+    start_time = time()
+    test_command = cmd
+    while True:
+        if (start_time + timeout) < time():
+            return None
+        result = run(test_command)
+        if result == 0:
+            return True
+        sleep(sleep_interval)
+
 @Interface.register
 class L2TPv3If(Interface):
     """
@@ -43,7 +63,9 @@ class L2TPv3If(Interface):
         cmd += ' encap {encapsulation}'
         cmd += ' local {source_address}'
         cmd += ' remote {remote}'
-        self._cmd(cmd.format(**self.config))
+        c = cmd.format(**self.config)
+        # wait until the local/remote address is available, but no more 10 sec.
+        wait_for_add_l2tpv3(cmd=c)
 
         # setup session
         cmd = 'ip l2tp add session name {ifname}'