fix #5364: bgp|evpn: derivated router-id from mac address for ipv6 underlay

for ipv4, we use the iface ipv4 router-id as router-id need to 32bit.

That's doesn't work for pure ipv6 underlay network.

since https://www.rfc-editor.org/rfc/rfc6286, we can use any 32bit id,
it's just need to be unique in the ASN.

Simply use the last 4 bytes of iface mac address as unique id

changelog V2: add missing test

Signed-off-by: Alexandre Derumier <alexandre.derumier@groupe-cyllene.com>
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>

1 files changed, 21 insertions, 0 deletions

diff --git a/src/PVE/Network/SDN/Controllers/Plugin.pm b/src/PVE/Network/SDN/Controllers/Plugin.pm
index c1c2cfd..5579513 100644
--- a/src/PVE/Network/SDN/Controllers/Plugin.pm
+++ b/src/PVE/Network/SDN/Controllers/Plugin.pm
@@ -118,4 +118,25 @@ sub on_update_hook {
     # do nothing by default
 }
 
+#helpers
+
+sub read_iface_mac {
+    my ($iface) = @_;
+    return PVE::Tools::file_read_firstline("/sys/class/net/$iface/master/address");
+}
+
+sub get_router_id {
+    my ($ip, $iface) = @_;
+
+    return $ip if Net::IP::ip_is_ipv4($ip);
+
+    #for ipv6, use 4 last bytes of iface mac address as unique id
+    my $mac = read_iface_mac($iface);
+
+    die "can't autofind a router-id value from ip or mac" if !$mac;
+
+    my @mac_bytes = split(':', $mac);
+    return hex($mac_bytes[2]).".".hex($mac_bytes[3]).".".hex($mac_bytes[4]).".".hex($mac_bytes[5]);
+}
+
 1;