func()

in google_guest_agent/network/manager/systemd_networkd_linux.go [271:356]
65 lines of code
10 McCabe index (conditional complexity)

func (n *systemdNetworkd) SetupVlanInterface(ctx context.Context, config *cfg.Sections, nics *Interfaces) error {
	var keepMe []string

	for _, curr := range nics.VlanInterfaces {
		iface := fmt.Sprintf("gcp.%s.%d", curr.ParentInterfaceID, curr.Vlan)

		// Create and setup .network file.
		networkConfig := systemdConfig{
			GuestAgent: guestAgentSection{
				ManagedByGuestAgent: true,
			},
			Match: systemdMatchConfig{
				Name: iface,
				Type: "vlan",
			},
			Network: systemdNetworkConfig{
				DHCP: "yes", // enables ipv4 and ipv6
			},
			Link: &systemdLinkConfig{
				MACAddress: curr.Mac,
				MTUBytes:   curr.MTU,
			},
		}

		if err := networkConfig.write(n, iface); err != nil {
			return fmt.Errorf("failed to write systemd's vlan .network config: %+v", err)
		}

		// Create and setup .netdev file.
		netdevConfig := systemdNetdevConfig{
			GuestAgent: guestAgentSection{
				ManagedByGuestAgent: true,
			},
			NetDev: systemdNetdev{
				Name: iface,
				Kind: "vlan",
			},
			VLAN: systemdVlan{
				ID:            curr.Vlan,
				ReorderHeader: false,
			},
		}

		if err := netdevConfig.write(n, iface); err != nil {
			return fmt.Errorf("failed to write systemd's vlan .netdev config: %+v", err)
		}

		// Add VLAN keys to the VLAN's parent .network config file.
		parentFile := n.networkFile(curr.ParentInterfaceID)
		parentConfig := new(systemdConfig)

		if err := readIniFile(parentFile, parentConfig); err != nil {
			return fmt.Errorf("failed to read vlan's parent interface .network config: %+v", err)
		}

		// Add the vlan interface to parents VLAN key if not there already.
		if !slices.Contains(parentConfig.Network.VLANS, iface) {
			parentConfig.Network.VLANS = append(parentConfig.Network.VLANS, iface)

			if err := parentConfig.write(n, curr.ParentInterfaceID); err != nil {
				return fmt.Errorf("error writing vlan parent's .network config: %+v", err)
			}
		}

		keepMe = append(keepMe, iface)
	}

	// Attempt to remove vlan interface configurations that are not known - i.e. they were previously
	// added by users but are no longer present on their mds configuration.
	requiresRestart, err := n.removeVlanInterfaces(ctx, keepMe)
	if err != nil {
		return fmt.Errorf("failed to remove vlan interface configuration: %+v", err)
	}

	if !requiresRestart {
		logger.Debugf("No changes applied to systemd-network's vlan config, skipping restart.")
		return nil
	}

	// Apply network changes avoiding to restart systemd-networkd.
	if err := run.Quiet(ctx, "networkctl", "reload"); err != nil {
		return fmt.Errorf("error reloading systemd-networkd network configs: %v", err)
	}

	return nil
}