From 122ef35bf9be456a075af1b6da1bd24142488bf0 Mon Sep 17 00:00:00 2001
From: Roopa Prabhu <roopa@cumulusnetworks.com>
Date: Thu, 17 Mar 2016 16:18:14 -0700
Subject: [PATCH] addons: vrf: release any dhcp leases before vrf slave
 enslavement

Ticket: CM-9929
Reviewed By:
Testing Done: Tested vrf dhcp slave enslavement on ifreload

algo:
- when a vrf slave enslavement changes, before performing the
  new master enslavement,
- check if vrf slave has dhcp configured
- if yes, release dhclient running on the vrf slave
---
 addons/vrf.py              | 43 ++++++++++++++++++++++++++++++++------
 ifupdownaddons/iproute2.py |  9 ++++++++
 2 files changed, 46 insertions(+), 6 deletions(-)

diff --git a/addons/vrf.py b/addons/vrf.py
index ba87ad7..979754c 100644
--- a/addons/vrf.py
+++ b/addons/vrf.py
@@ -13,6 +13,7 @@ import ifupdown.rtnetlink_api as rtnetlink_api
 from ifupdownaddons.modulebase import moduleBase
 from ifupdownaddons.bondutil import bondutil
 from ifupdownaddons.iproute2 import iproute2
+from ifupdownaddons.dhclient import dhclient
 
 class vrfPrivFlags:
     PROCESSED = 0x1
@@ -44,7 +45,19 @@ class vrf(moduleBase):
         ifupdownaddons.modulebase.moduleBase.__init__(self, *args, **kargs)
         self.ipcmd = None
         self.bondcmd = None
+        self.dhclientcmd = None
         self.name = self.__class__.__name__
+        if self.PERFMODE:
+            # if perf mode is set, remove vrf map file.
+            # start afresh. PERFMODE is set at boot
+            if os.path.exists(self.iproute2_vrf_filename):
+                try:
+                    self.logger.info('vrf: removing file %s'
+                                     %self.iproute2_vrf_filename)
+                    os.remove(self.iproute2_vrf_filename)
+                except Exception, e:
+                    self.logger.debug('vrf: removing file failed (%s)'
+                                      %str(e))
         try:
             ip_rules = self.exec_command('/sbin/ip rule show').splitlines()
             self.ip_rule_cache = [' '.join(r.split()) for r in ip_rules]
@@ -190,16 +203,20 @@ class vrf(moduleBase):
                              %(table_id, str(e)))
             pass
 
+    def _is_dhcp_slave(self, ifaceobj):
+        if (not ifaceobj.addr_method or
+            (ifaceobj.addr_method != 'dhcp' and
+             ifaceobj.addr_method != 'dhcp6')):
+                return False
+        return True
+
     def _handle_dhcp_slaves(self, ifacename, vrfname, ifaceobj,
                             ifaceobj_getfunc):
         """ If we have a vrf slave that has dhcp configured, bring up the
             vrf master now. This is needed because vrf has special handling
             in dhclient hook which requires the vrf master to be present """
-
-        if (not ifaceobj.addr_method or
-            (ifaceobj.addr_method != 'dhcp' and
-             ifaceobj.addr_method != 'dhcp6')):
-                return
+        if not self._is_dhcp_slave(ifaceobj):
+            return False
         vrf_master = ifaceobj.upperifaces[0]
         if not vrf_master:
             self.logger.warn('%s: vrf master not found' %ifacename)
@@ -226,14 +243,26 @@ class vrf(moduleBase):
                                      %(mobj.name, vrf_table))
                 self._up_vrf_dev(mobj, vrf_table, False)
                 break
+        self._down_dhcp_slave(ifaceobj)
         self.ipcmd.link_set(ifacename, 'master', vrfname)
         return
 
+    def _down_dhcp_slave(self, ifaceobj):
+        try:
+            self.dhclientcmd.release(ifaceobj.name)
+        except:
+            # ignore any dhclient release errors
+            pass
+
     def _up_vrf_slave(self, ifacename, vrfname, ifaceobj=None,
                       ifaceobj_getfunc=None):
         try:
             if self.ipcmd.link_exists(vrfname):
-                self.ipcmd.link_set(ifacename, 'master', vrfname)
+                upper = self.ipcmd.link_get_upper(vrfname)
+                if upper and upper != vrfname:
+                    if self._is_dhcp_slave(ifaceobj):
+                        self._down_dhcp_slave(ifaceobj)
+                    self.ipcmd.link_set(ifacename, 'master', vrfname)
             elif ifaceobj:
                 self._handle_dhcp_slaves(ifacename, vrfname, ifaceobj,
                                          ifaceobj_getfunc)
@@ -590,6 +619,8 @@ class vrf(moduleBase):
             self.ipcmd = iproute2(**flags)
         if not self.bondcmd:
             self.bondcmd = bondutil(**flags)
+        if not self.dhclientcmd:
+            self.dhclientcmd = dhclient(**flags)
 
     def run(self, ifaceobj, operation, query_ifaceobj=None,
             ifaceobj_getfunc=None, **extra_args):
diff --git a/ifupdownaddons/iproute2.py b/ifupdownaddons/iproute2.py
index eecf358..15888a4 100644
--- a/ifupdownaddons/iproute2.py
+++ b/ifupdownaddons/iproute2.py
@@ -838,3 +838,12 @@ class iproute2(utilsBase):
             return [os.path.basename(l)[6:] for l in lowers]
         except:
             return []
+
+    def link_get_upper(self, ifacename):
+        try:
+            upper = glob.glob("/sys/class/net/%s/upper_*" %ifacename)
+            if not upper:
+                return None
+            return os.path.basename(upper[0])[6:]
+        except:
+            return None