topologies: handle `enable_v4` attribute for links

README.md

@@ -64,6 +64,7 @@ looking like this:
 ---
 links:
   - domains: ['a', 'b']
+    enable_v4: false
   - domains: ['b', 'c']
 domains:
   b:
@@ -75,8 +76,13 @@ attribute, the list of domains (containers) connected to it. A domain is
 described by an arbitrary name. Domains will be spawned (and indexed) in
 alphabetical order.
 
+The valid options for links are:
+* `enable_v4`: boolean, specifies whether the NICs connected to this link have
+  an IPv4 address.
+
 A `domains` root element is optional, and may be used to specify
 domain-specific options.
 
-The valid options are:
-* `enable_v4`: boolean, specifies whether the domain has an IPv4 address.
+The valid options for domains are:
+* `enable_v4`: boolean, specifies whether the domain has IPv4 addresses on its
+  NICs.

lxc_net/container.py

@@ -174,7 +174,9 @@ class Container(util.LibvirtObject):
         for net in self.networks:
             net_config = net_config_templ.inst(
                 mac=util.MACAddress(net.id, self.id),
-                ipv4=util.Addrv4(net.id, self.id) if self.enable_v4 else None,
+                ipv4=util.Addrv4(net.id, self.id)
+                if self.enable_v4 and net.enable_v4
+                else None,
                 ipv6=util.Addrv6(net.id, self.id),
             )
             net_config_path = net_conf_dir / "11-{link:02d}-{name}.network".format(

lxc_net/network.py

@@ -12,13 +12,14 @@ class Network(util.LibvirtObject):
         def __str__(self):
             return "This network is already instanciated"
 
-    def __init__(self, conn, name=None):
+    def __init__(self, conn, name=None, enable_v4=True):
         super().__init__(conn)
 
         if not name:
             name = str(self.id)
 
         self.name = settings.PREFIX + "_link_" + name
+        self.enable_v4 = enable_v4
         self.bridge_id = settings.NETWORK_ID * 0xFF + self.id
         self.bridge_mac = util.MACAddress(self.id, None)
         self.ipv4 = util.Addrv4(self.id, None, host_address=True)

lxc_net/parse_network.py

@@ -214,7 +214,9 @@ class YamlTopology(Topology):
                     "a 'domains' attribute is mandatory for each link"
                 )
 
-            cur_link = network.Network(self.conn)
+            cur_link = network.Network(
+                self.conn, enable_v4=link_conf.get("enable_v4", True),
+            )
             self.links.append(cur_link)
 
             for dom in link_conf["domains"]: