IPv6 Subnets configured to use external router should not be allowed to associate to Neutron Router.

Fix proposed to branch: master
Review: https://review.openstack.org/136733

Reviewed: https://review.openstack.org/136733
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=e5713f932482210107dcfd7bac6a78524c8bad26
Submitter: Jenkins
Branch: master

commit e5713f932482210107dcfd7bac6a78524c8bad26
Author: sridhargaddam <email address hidden>
Date: Mon Nov 24 10:17:36 2014 +0000

    Validate IPv6 subnet while associating to Router

    Currently Neutron allows attaching a subnet (configured to use an external
    router, by only setting ipv6_address_mode and leaving ipv6_ra_mode unset)
    to Neutron Router. Ideally Neutron should not allow this operation and
    should return an appropriate error message to the user.

    APIImpact
    Closes-Bug: #1393527
    Change-Id: I9d597e6f5e8aea63222bb9f5ed8289e4ce28bbc3

Sridhar , can you explain please what is the correct neutron command that I need to type to associate Stateless subnet to external router ?

for example this command is not valid according to the bug :
1. Create tenant_a Provider Stateless DHCPv6 network:
      a. Create IPv6 internal network (name it tenant_a_provider_stateless).
      # neutron net-create tenant_a_provider_stateless --router:external True

   b. Create IPv6 Provider Stateless DHCPv6 subnet and attached to tenant_a_provider_stateless

      # neutron subnet-create <tenant_a_provider_stateless_id> 2001:db4:0::2/64 --name tenant_a_provider_stateless_subnet --ipv6-address-mode dhcpv6-stateless --gateway fe80::6664:9bff:fe17:b40 --dns-nameserver 2001:4860:4860::8888 --ip-version 6
** according the bug we should get an error message
as I understand I should add this value :
-ipv6-ra-mode=dhcpv6-stateless
full command :
      # neutron subnet-create <tenant_a_provider_stateless_id> 2001:db4:0::2/64 --name tenant_a_provider_stateless_subnet --ipv6-address-mode dhcpv6-stateless -ipv6-ra-mode=dhcpv6-stateless --gateway fe80::6664:9bff:fe17:b40 --dns-nameserver 2001:4860:4860::8888 --ip-version 6

@Eran, step 1 and 2 above is fine. This bug addresses the following situation.
Now if you try to associate the subnet to a neutron router, you will be getting an error (i.e., Step 4 below).

Step 3: neutron router-create ipv6-router
Step 4: neutron router-interface-add ipv6-router tenant_a_provider_stateless_subnet
Bad router request: IPv6 subnet cb5629e8-1762-45d3-8102-cf691503ef83 configured to receive RAs from an external router cannot be added to Neutron Router.