sonic-buildimage/dockers/docker-dhcp-relay/dhcpv4-relay.agents.j2
shlomibitton 1ebe52847a
[DHCPv6 relay] [202106] Fix DHCPv6 design to support multiple VLANS (#9163)
- Why I did it
If multiple Vlans are configured to have DHCPv6 relay, only one relay instance is able to capture DHCP packets received from upstream, this is as a result of kernel design to operate this way (SO_REUSEPORT).
DHCPv6 transmit unicast packets to clients, only multicast packets can be captured on multiple application listening on the same UDP port.
This issue causing only one Vlan interface to get packets from servers.

- How I did it
Change the design to neglect Vlan isolation and run only one relay instance serving all Vlans with all configured DHCP servers.

- How to verify it
Run DHCPv6 relay test with 2 Vlans configured do have a DHCP relay.

Signed-off-by: Shlomi Bitton <shlomibi@nvidia.com>
2021-11-18 19:40:48 +02:00

43 lines
1.8 KiB
Django/Jinja

{# Append DHCPv4 agents #}
{% set relay_for_ipv4 = { 'flag': False } %}
{% for vlan_name in VLAN_INTERFACE %}
{% if VLAN and vlan_name in VLAN and 'dhcp_servers' in VLAN[vlan_name] and VLAN[vlan_name]['dhcp_servers']|length > 0 %}
{% for dhcp_server in VLAN[vlan_name]['dhcp_servers'] %}
{% if dhcp_server | ipv4 %}
{% set _dummy = relay_for_ipv4.update({'flag': True}) %}
{% endif %}
{% endfor %}
{% if relay_for_ipv4.flag %}
{% set _dummy = relay_for_ipv4.update({'flag': False}) %}
[program:isc-dhcpv4-relay-{{ vlan_name }}]
{# We treat this VLAN as a downstream interface (-id), as we only want to listen for requests #}
command=/usr/sbin/dhcrelay -d -m discard -a %%h:%%p %%P --name-alias-map-file /tmp/port-name-alias-map.txt -id {{ vlan_name }}
{#- Dual ToR Option #}
{% if 'subtype' in DEVICE_METADATA['localhost'] and DEVICE_METADATA['localhost']['subtype'] == 'DualToR' %} -U Loopback0 -dt{% endif -%}
{#- si option to use intf addr in relay #}
{% if DEVICE_METADATA['localhost']['deployment_id'] == '8' %} -si{% endif -%}
{#- We treat all other interfaces as upstream interfaces (-iu), as we only want to listen for replies #}
{% for (name, prefix) in VLAN_INTERFACE|pfx_filter %}
{% if prefix | ipv4 and name != vlan_name %} -iu {{ name }}{% endif -%}
{% endfor %}
{% for (name, prefix) in INTERFACE|pfx_filter %}
{% if prefix | ipv4 %} -iu {{ name }}{% endif -%}
{% endfor %}
{% for (name, prefix) in PORTCHANNEL_INTERFACE|pfx_filter %}
{% if prefix | ipv4 %} -iu {{ name }}{% endif -%}
{% endfor %}
{% for dhcp_server in VLAN[vlan_name]['dhcp_servers'] %}
{%- if dhcp_server | ipv4 %} {{ dhcp_server }}{% endif -%}
{% endfor %}
priority=3
autostart=false
autorestart=false
stdout_logfile=syslog
stderr_logfile=syslog
dependent_startup=true
dependent_startup_wait_for=start:exited
{% endif %}
{% endif %}
{% endfor %}