RADVD Problem on PPPeO link without public IPv6 address

[Droppie391]

Our ISP does NOT provide ipv6 address but uses Lokal-Link address on the PPPoE link, which results in radvd not starting.
Looking at the generated /var/etc/radvd.conf for the WAN interface shows the problem:

# Automatically Generated, do not edit
# Generated for DHCPv6 Server wan
interface igb0 {
   AdvSendAdvert on;
   MinRtrAdvInterval 200;
   MaxRtrAdvInterval 600;
   AdvLinkMTU 1470;
   AdvDefaultPreference medium;
   prefix / {
      DeprecatePrefix on;
      AdvOnLink off;
      AdvAutonomous off;
      AdvRouterAddr on;
   };
   route ::/0 {
      RemoveRoute on;
   };
   DNSSL my.domain { };
};

In the prefix block, no range nor subnet mask is specified, causing radvd to crash.

Adding a virtual ip address to the wan interface results radvd to crash as well. The generated radvd.conf now
shows 2 prefix blocks, one for the virtual and one for the default, non existing ip address:

# Automatically Generated, do not edit
# Generated for DHCPv6 Server wan
interface igb0 {
   AdvSendAdvert on;
   MinRtrAdvInterval 200;
   MaxRtrAdvInterval 600;
   AdvLinkMTU 1470;
   AdvDefaultPreference medium;
   prefix / {
      DeprecatePrefix on;
      AdvOnLink off;
      AdvAutonomous off;
      AdvRouterAddr on;
   };
   prefix 2001:1234:5678::/48 {
      DeprecatePrefix on;
      AdvOnLink off;
      AdvAutonomous off;
      AdvRouterAddr on;
   };
   route ::/0 {
      RemoveRoute on;
   };
   DNSSL my.domain { };
};

Again, radvd crashes on the missing address and subnet in the first prefix block

Removing the first prefix block and manually starting radvd gets us going.

in /usr/local/etc/inc/service.inc, the following section seems to set these prefix blocks

        $stanzas = array();
        $ifcfgsnv6 = get_interface_subnetv6($dhcpv6if);
        $subnetv6 = gen_subnetv6($ifcfgipv6, $ifcfgsnv6);
        $stanzas[] = "{$subnetv6}/{$ifcfgsnv6}";

        $viparr = &config_read_array('virtualip', 'vip');
        foreach ($viparr as $vip) {
            if ($vip['interface'] == $dhcpv6if && is_ipaddrv6($vip['subnet'])) {
                $ifcfgsnv6 = $vip['subnet_bits'];
                $subnetv6 = gen_subnetv6($vip['subnet'], $ifcfgsnv6);
                $stanzas[] = "{$subnetv6}/{$ifcfgsnv6}";
            }
        }

If $ifcfgsnv6 if checked for an empty value, the config file is generated correctly and radvd runs fine:

        $stanzas = array();
        $ifcfgsnv6 = get_interface_subnetv6($dhcpv6if);
      if ($ifcfgsnv6) {
          $subnetv6 = gen_subnetv6($ifcfgipv6, $ifcfgsnv6);
          $stanzas[] = "{$subnetv6}/{$ifcfgsnv6}";
      }
   
Resulting radvd.conf:

# Automatically Generated, do not edit
# Generated for DHCPv6 Server wan
interface igb0 {
   AdvSendAdvert on;
   MinRtrAdvInterval 200;
   MaxRtrAdvInterval 600;
   AdvLinkMTU 1470;
   AdvDefaultPreference medium;
   route ::/0 {
      RemoveRoute on;
   };
   DNSSL my.domain { };
};
   
Please review the code to eliminate this error condition, thanks.

[marjohn56]

I cannot check this on my system as I have a good ISP who gives me a global on my WAN, in fact I get a /64 on my WAN as well as a /48 on the LAN....

No one else has complained of this, I'll do a patch and review it on Github,

I have created a patch, it's from my fork but I have raised a PR to the master and asked for a review. Try this and see if it does what's needed.

# opnsense-patch af952a2

[Droppie391]

Thanks, works like a charm 

[marjohn56]

Just made a minor change to it so the patch ID has changed to ab5f271 for anyone else. It should be pulled soon and will be part of the next release.

Update... merged.

[Droppie391]

patched the changes as well, working fine, thanks

[franco]

Was merged and will hit 18.1.3 for sure. Thank you for the analysis and patch!


Cheers,
Franco