From 99ce689411b78f031ebeac19beb0f94e631c27c7 Mon Sep 17 00:00:00 2001
From: Roopa Prabhu <roopa@cumulusnetworks.com>
Date: Tue, 8 Mar 2016 20:40:02 -0800
Subject: [PATCH] ifupdownmain: squash multiple iface stanzas for the same
 interface

Ticket:
Reviewed By: CCR-4268
Testing Done: Tested squashing of interfaces with multiple iface stanzas

This is controlled by ifaceobj_squash config variable in
/etc/network/ifupdown2/ifupdown2.conf.

With ifaceobj_squash=1, ifquery and all commands will
output squashed interfaces.

$cat /etc/network/interfaces
auto swp3
iface swp3
    mtu 9000

auto swp3
iface swp3 inet static
    address 10.0.17.3/24

auto swp3
iface swp3 inet static
    address 10.0.18.3/24
    address 2000:1000:1000:1000:3::5/128

$ifquery -a
auto lo
iface lo inet loopback

auto eth0
iface eth0 inet dhcp

auto swp3
iface swp3
        mtu 9000
        address 10.0.17.3/24
        address 10.0.18.3/24
        address 2000:1000:1000:1000:3::5/128

When and why do we need this ?
- If we preserve multiple ifaceobjects for the same iface,
it gets tricky in some cases to set default policy
values because the addon module run methods are called
on each ifaceobject.
- Each ifaceobject belonging to the same interface
is treated as a separate interface. It is difficult
to remember things accross addon module run methods
- we have a few hacks in place which we would like to
get rid of

Why not turn it on by default ?
- still debating about it. Dont want to break existing
scripts with change of output. Will get some feedback before
I switch the default to squash.
---
 config/ifupdown2.conf    |  5 +++++
 ifupdown/iface.py        | 10 ++++++++++
 ifupdown/ifupdownmain.py | 14 +++++++++++---
 3 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/config/ifupdown2.conf b/config/ifupdown2.conf
index cc7fd0f..d5b808a 100644
--- a/config/ifupdown2.conf
+++ b/config/ifupdown2.conf
@@ -53,3 +53,8 @@ ifreload_down_changed=0
 
 # squash all addr config when you process the first interface
 addr_config_squash=0
+
+# squash iface config into one when you have multiple
+# ifaces stanzas for an interface
+ifaceobj_squash=0
+
diff --git a/ifupdown/iface.py b/ifupdown/iface.py
index 2f7fd1c..e7e2e89 100644
--- a/ifupdown/iface.py
+++ b/ifupdown/iface.py
@@ -527,6 +527,16 @@ class iface():
                     if v != dstiface.config.get(k)): return False
         return True
 
+    def squash(self, newifaceobj):
+        """ This squashes the iface object """
+        for attrname, attrlist in newifaceobj.config.iteritems():
+            # if allready present add it to the list
+            # else add it to the end of the dictionary
+            # We need to maintain order.
+            if self.config.get(attrname):
+                self.config[attrname].extend(attrlist)
+            else:
+                self.config.update([(attrname, attrlist)])
 
     def __getstate__(self):
         odict = self.__dict__.copy()
diff --git a/ifupdown/ifupdownmain.py b/ifupdown/ifupdownmain.py
index b759f68..686b6bf 100644
--- a/ifupdown/ifupdownmain.py
+++ b/ifupdown/ifupdownmain.py
@@ -262,6 +262,9 @@ class ifupdownMain(ifupdownBase):
                              'state changes will be delayed till the ' +
                              'masters admin state change.')
 
+        self._ifaceobj_squash = True if self.config.get(
+                            'ifaceobj_squash', '0') == '1' else False
+
         # initialize global config object with config passed by the user
         # This makes config available to addon modules
         ifupdownConfig.config = self.config
@@ -661,9 +664,14 @@ class ifupdownMain(ifupdownBase):
            ifaceobj.link_type = ifaceLinkType.LINK_NA
         currentifaceobjlist = self.ifaceobjdict.get(ifaceobj.name)
         if not currentifaceobjlist:
-           self.ifaceobjdict[ifaceobj.name]= [ifaceobj]
-           ifaceobj.flags |= ifaceobj.YOUNGEST_SIBLING
-           return
+            self.ifaceobjdict[ifaceobj.name]= [ifaceobj]
+            if not self._ifaceobj_squash:
+                ifaceobj.flags |= ifaceobj.YOUNGEST_SIBLING
+            return
+        if self._ifaceobj_squash:
+            # squash with old iface object
+            currentifaceobjlist[0].squash(ifaceobj)
+            return
         if ifaceobj.compare(currentifaceobjlist[0]):
             self.logger.warn('duplicate interface %s found' %ifaceobj.name)
             return