dhclient: wait to start dhcp if carrier is down

This prevents DHCP requests failures taking time during
boot if the interface isn't up yet. If the interface is
down, dhclient will fail to send packets.

At boot-time, enslaving an interface to vrf flaps it. By
waiting for the interface to come back up before starting
dhclient reduces time to boot.

Reviewed-by: CCR-10987
Closes: CM-32460
Co-developed-by: Nilesh Shinde <nilesh@nvidia.com>
Signed-off-by: Andy Roulin <aroulin@nvidia.com>

diff --git a/ifupdown2/ifupdownaddons/dhclient.py b/ifupdown2/ifupdownaddons/dhclient.py
index cf03f9a1c53173420ef9819fb97e1f1751a911a9..ef849d6b21a11c6c76357ff516a8698d25a69caf 100644 (file)
--- a/ifupdown2/ifupdownaddons/dhclient.py
+++ b/ifupdown2/ifupdownaddons/dhclient.py
@@ -66,6 +66,16 @@ class dhclient(utilsBase):
         self._run_dhclient_cmd(cmd, cmd_prefix)
 
     def start(self, ifacename, wait=True, cmd_prefix=None):
+        retries = 0
+        out = "0"
+
+        # wait if interface isn't up yet
+        while '1' not in out and retries < 5:
+            path = 'sys/class/net/%s/carrier' %ifacename
+            out = self.read_file_oneline(path)
+            retries += 1
+            time.sleep(1)
+
         if os.path.exists('/sbin/dhclient3'):
             cmd = ['/sbin/dhclient3', '-pf',
                    '/run/dhclient.%s.pid' %ifacename,