dhcpv6: T2961: support stateless dhcpv6 clients

This commit adds support for configuring the DHCPv6 server to serve
"stateless" DHCPv6 clients (those that send an information-request
message and do not request an address).

The change introduces a `common-options` node at the
`shared-network-name` level, which allows specifying options
applicable to clients regardless of subnet assigned (or in the case of
stateless clients, when no subnet is assigned). Parameters specified
at the subnet level take precedence over those set at the
shared-network level.

Presently, only parameters that are meaningful to stateless clients
have been exposed under `common-options`, as there is no precedent of
exposing parameters at multiple levels under the current DHCPv4 or
DHCPv6 configuration syntax. If desired, additional parameters could
certainly be added with relative ease.

1 files changed, 9 insertions, 0 deletions

diff --git a/data/templates/dhcpv6-server/dhcpdv6.conf.tmpl b/data/templates/dhcpv6-server/dhcpdv6.conf.tmpl
index ff7822b0d..bdeea71da 100644
--- a/data/templates/dhcpv6-server/dhcpdv6.conf.tmpl
+++ b/data/templates/dhcpv6-server/dhcpdv6.conf.tmpl
@@ -12,6 +12,15 @@ option dhcp6.preference {{ preference }};
 {% for network in shared_network %}
 {%- if not network.disabled -%}
 shared-network {{ network.name }} {
+    {%- if network.common.info_refresh_time %}
+    option dhcp6.info-refresh-time {{ network.common.info_refresh_time }};
+    {%- endif %}
+    {%- if network.common.domain_search %}
+    option dhcp6.domain-search "{{ network.common.domain_search | join('", "') }}";
+    {%- endif %}
+    {%- if network.common.dns_server %}
+    option dhcp6.name-servers {{ network.common.dns_server | join(', ') }};
+    {%- endif %}
     {%- for subnet in network.subnet %}
     subnet6 {{ subnet.network }} {
         {%- for range in subnet.range6_prefix %}