Mikrotik integration (#467)

Allow MikroTik routes as WireGuard backends

internal/adapters/wgcontroller/local.go

@@ -0,0 +1,864 @@
+package wgcontroller
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"log/slog"
+	"os"
+	"os/exec"
+	"strings"
+	"time"
+
+	probing "github.com/prometheus-community/pro-bing"
+	"github.com/vishvananda/netlink"
+	"golang.org/x/sys/unix"
+	"golang.zx2c4.com/wireguard/wgctrl"
+	"golang.zx2c4.com/wireguard/wgctrl/wgtypes"
+
+	"github.com/h44z/wg-portal/internal"
+	"github.com/h44z/wg-portal/internal/config"
+	"github.com/h44z/wg-portal/internal/domain"
+	"github.com/h44z/wg-portal/internal/lowlevel"
+)
+
+// region dependencies
+
+// WgCtrlRepo is used to control local WireGuard devices via the wgctrl-go library.
+type WgCtrlRepo interface {
+	io.Closer
+	Devices() ([]*wgtypes.Device, error)
+	Device(name string) (*wgtypes.Device, error)
+	ConfigureDevice(name string, cfg wgtypes.Config) error
+}
+
+// A NetlinkClient is a type which can control a netlink device.
+type NetlinkClient interface {
+	LinkAdd(link netlink.Link) error
+	LinkDel(link netlink.Link) error
+	LinkByName(name string) (netlink.Link, error)
+	LinkSetUp(link netlink.Link) error
+	LinkSetDown(link netlink.Link) error
+	LinkSetMTU(link netlink.Link, mtu int) error
+	AddrReplace(link netlink.Link, addr *netlink.Addr) error
+	AddrAdd(link netlink.Link, addr *netlink.Addr) error
+	AddrList(link netlink.Link) ([]netlink.Addr, error)
+	AddrDel(link netlink.Link, addr *netlink.Addr) error
+	RouteAdd(route *netlink.Route) error
+	RouteDel(route *netlink.Route) error
+	RouteReplace(route *netlink.Route) error
+	RouteList(link netlink.Link, family int) ([]netlink.Route, error)
+	RouteListFiltered(family int, filter *netlink.Route, filterMask uint64) ([]netlink.Route, error)
+	RuleAdd(rule *netlink.Rule) error
+	RuleDel(rule *netlink.Rule) error
+	RuleList(family int) ([]netlink.Rule, error)
+}
+
+// endregion dependencies
+
+type LocalController struct {
+	cfg *config.Config
+
+	wg WgCtrlRepo
+	nl NetlinkClient
+
+	shellCmd              string
+	resolvConfIfacePrefix string
+}
+
+// NewLocalController creates a new local controller instance.
+// This repository is used to interact with the WireGuard kernel or userspace module.
+func NewLocalController(cfg *config.Config) (*LocalController, error) {
+	wg, err := wgctrl.New()
+	if err != nil {
+		return nil, fmt.Errorf("failed to create wgctrl client: %w", err)
+	}
+
+	nl := &lowlevel.NetlinkManager{}
+
+	repo := &LocalController{
+		cfg: cfg,
+
+		wg: wg,
+		nl: nl,
+
+		shellCmd:              "bash", // we only support bash at the moment
+		resolvConfIfacePrefix: "tun.", // WireGuard interfaces have a tun. prefix in resolvconf
+	}
+
+	return repo, nil
+}
+
+func (c LocalController) GetId() domain.InterfaceBackend {
+	return config.LocalBackendName
+}
+
+// region wireguard-related
+
+func (c LocalController) GetInterfaces(_ context.Context) ([]domain.PhysicalInterface, error) {
+	devices, err := c.wg.Devices()
+	if err != nil {
+		return nil, fmt.Errorf("device list error: %w", err)
+	}
+
+	interfaces := make([]domain.PhysicalInterface, 0, len(devices))
+	for _, device := range devices {
+		interfaceModel, err := c.convertWireGuardInterface(device)
+		if err != nil {
+			return nil, fmt.Errorf("interface convert failed for %s: %w", device.Name, err)
+		}
+		interfaces = append(interfaces, interfaceModel)
+	}
+
+	return interfaces, nil
+}
+
+func (c LocalController) GetInterface(_ context.Context, id domain.InterfaceIdentifier) (
+	*domain.PhysicalInterface,
+	error,
+) {
+	return c.getInterface(id)
+}
+
+func (c LocalController) convertWireGuardInterface(device *wgtypes.Device) (domain.PhysicalInterface, error) {
+	// read data from wgctrl interface
+
+	iface := domain.PhysicalInterface{
+		Identifier: domain.InterfaceIdentifier(device.Name),
+		KeyPair: domain.KeyPair{
+			PrivateKey: device.PrivateKey.String(),
+			PublicKey:  device.PublicKey.String(),
+		},
+		ListenPort:    device.ListenPort,
+		Addresses:     nil,
+		Mtu:           0,
+		FirewallMark:  uint32(device.FirewallMark),
+		DeviceUp:      false,
+		ImportSource:  domain.ControllerTypeLocal,
+		DeviceType:    device.Type.String(),
+		BytesUpload:   0,
+		BytesDownload: 0,
+	}
+
+	// read data from netlink interface
+
+	lowLevelInterface, err := c.nl.LinkByName(device.Name)
+	if err != nil {
+		return domain.PhysicalInterface{}, fmt.Errorf("netlink error for %s: %w", device.Name, err)
+	}
+	ipAddresses, err := c.nl.AddrList(lowLevelInterface)
+	if err != nil {
+		return domain.PhysicalInterface{}, fmt.Errorf("ip read error for %s: %w", device.Name, err)
+	}
+
+	for _, addr := range ipAddresses {
+		iface.Addresses = append(iface.Addresses, domain.CidrFromNetlinkAddr(addr))
+	}
+	iface.Mtu = lowLevelInterface.Attrs().MTU
+	iface.DeviceUp = lowLevelInterface.Attrs().OperState == netlink.OperUnknown // wg only supports unknown
+	if stats := lowLevelInterface.Attrs().Statistics; stats != nil {
+		iface.BytesUpload = stats.TxBytes
+		iface.BytesDownload = stats.RxBytes
+	}
+
+	return iface, nil
+}
+
+func (c LocalController) GetPeers(_ context.Context, deviceId domain.InterfaceIdentifier) (
+	[]domain.PhysicalPeer,
+	error,
+) {
+	device, err := c.wg.Device(string(deviceId))
+	if err != nil {
+		return nil, fmt.Errorf("device error: %w", err)
+	}
+
+	peers := make([]domain.PhysicalPeer, 0, len(device.Peers))
+	for _, peer := range device.Peers {
+		peerModel, err := c.convertWireGuardPeer(&peer)
+		if err != nil {
+			return nil, fmt.Errorf("peer convert failed for %v: %w", peer.PublicKey, err)
+		}
+		peers = append(peers, peerModel)
+	}
+
+	return peers, nil
+}
+
+func (c LocalController) convertWireGuardPeer(peer *wgtypes.Peer) (domain.PhysicalPeer, error) {
+	peerModel := domain.PhysicalPeer{
+		Identifier: domain.PeerIdentifier(peer.PublicKey.String()),
+		Endpoint:   "",
+		AllowedIPs: nil,
+		KeyPair: domain.KeyPair{
+			PublicKey: peer.PublicKey.String(),
+		},
+		PresharedKey:        "",
+		PersistentKeepalive: int(peer.PersistentKeepaliveInterval.Seconds()),
+		LastHandshake:       peer.LastHandshakeTime,
+		ProtocolVersion:     peer.ProtocolVersion,
+		BytesUpload:         uint64(peer.ReceiveBytes),
+		BytesDownload:       uint64(peer.TransmitBytes),
+		ImportSource:        domain.ControllerTypeLocal,
+	}
+
+	// Set local extras - local peers are never disabled in the kernel
+	peerModel.SetExtras(domain.LocalPeerExtras{
+		Disabled: false,
+	})
+
+	for _, addr := range peer.AllowedIPs {
+		peerModel.AllowedIPs = append(peerModel.AllowedIPs, domain.CidrFromIpNet(addr))
+	}
+	if peer.Endpoint != nil {
+		peerModel.Endpoint = peer.Endpoint.String()
+	}
+	if peer.PresharedKey != (wgtypes.Key{}) {
+		peerModel.PresharedKey = domain.PreSharedKey(peer.PresharedKey.String())
+	}
+
+	return peerModel, nil
+}
+
+func (c LocalController) SaveInterface(
+	_ context.Context,
+	id domain.InterfaceIdentifier,
+	updateFunc func(pi *domain.PhysicalInterface) (*domain.PhysicalInterface, error),
+) error {
+	physicalInterface, err := c.getOrCreateInterface(id)
+	if err != nil {
+		return err
+	}
+
+	if updateFunc != nil {
+		physicalInterface, err = updateFunc(physicalInterface)
+		if err != nil {
+			return err
+		}
+	}
+
+	if err := c.updateLowLevelInterface(physicalInterface); err != nil {
+		return err
+	}
+	if err := c.updateWireGuardInterface(physicalInterface); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (c LocalController) getOrCreateInterface(id domain.InterfaceIdentifier) (*domain.PhysicalInterface, error) {
+	device, err := c.getInterface(id)
+	if err == nil {
+		return device, nil // interface exists
+	}
+	if !errors.Is(err, os.ErrNotExist) {
+		return nil, fmt.Errorf("device error: %w", err) // unknown error
+	}
+
+	// create new device
+	if err := c.createLowLevelInterface(id); err != nil {
+		return nil, err
+	}
+
+	device, err = c.getInterface(id)
+	return device, err
+}
+
+func (c LocalController) getInterface(id domain.InterfaceIdentifier) (*domain.PhysicalInterface, error) {
+	device, err := c.wg.Device(string(id))
+	if err != nil {
+		return nil, err
+	}
+
+	pi, err := c.convertWireGuardInterface(device)
+	return &pi, err
+}
+
+func (c LocalController) createLowLevelInterface(id domain.InterfaceIdentifier) error {
+	link := &netlink.GenericLink{
+		LinkAttrs: netlink.LinkAttrs{
+			Name: string(id),
+		},
+		LinkType: "wireguard",
+	}
+	err := c.nl.LinkAdd(link)
+	if err != nil {
+		return fmt.Errorf("link add failed: %w", err)
+	}
+
+	return nil
+}
+
+func (c LocalController) updateLowLevelInterface(pi *domain.PhysicalInterface) error {
+	link, err := c.nl.LinkByName(string(pi.Identifier))
+	if err != nil {
+		return err
+	}
+	if pi.Mtu != 0 {
+		if err := c.nl.LinkSetMTU(link, pi.Mtu); err != nil {
+			return fmt.Errorf("mtu error: %w", err)
+		}
+	}
+
+	for _, addr := range pi.Addresses {
+		err := c.nl.AddrReplace(link, addr.NetlinkAddr())
+		if err != nil {
+			return fmt.Errorf("failed to set ip %s: %w", addr.String(), err)
+		}
+	}
+
+	// Remove unwanted IP addresses
+	rawAddresses, err := c.nl.AddrList(link)
+	if err != nil {
+		return fmt.Errorf("failed to fetch interface ips: %w", err)
+	}
+	for _, rawAddr := range rawAddresses {
+		netlinkAddr := domain.CidrFromNetlinkAddr(rawAddr)
+		remove := true
+		for _, addr := range pi.Addresses {
+			if addr == netlinkAddr {
+				remove = false
+				break
+			}
+		}
+
+		if !remove {
+			continue
+		}
+
+		err := c.nl.AddrDel(link, &rawAddr)
+		if err != nil {
+			return fmt.Errorf("failed to remove deprecated ip %s: %w", netlinkAddr.String(), err)
+		}
+	}
+
+	// Update link state
+	if pi.DeviceUp {
+		if err := c.nl.LinkSetUp(link); err != nil {
+			return fmt.Errorf("failed to bring up device: %w", err)
+		}
+	} else {
+		if err := c.nl.LinkSetDown(link); err != nil {
+			return fmt.Errorf("failed to bring down device: %w", err)
+		}
+	}
+
+	return nil
+}
+
+func (c LocalController) updateWireGuardInterface(pi *domain.PhysicalInterface) error {
+	pKey, err := wgtypes.NewKey(pi.KeyPair.GetPrivateKeyBytes())
+	if err != nil {
+		return err
+	}
+
+	var fwMark *int
+	if pi.FirewallMark != 0 {
+		intFwMark := int(pi.FirewallMark)
+		fwMark = &intFwMark
+	}
+	err = c.wg.ConfigureDevice(string(pi.Identifier), wgtypes.Config{
+		PrivateKey:   &pKey,
+		ListenPort:   &pi.ListenPort,
+		FirewallMark: fwMark,
+		ReplacePeers: false,
+	})
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (c LocalController) DeleteInterface(_ context.Context, id domain.InterfaceIdentifier) error {
+	if err := c.deleteLowLevelInterface(id); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (c LocalController) deleteLowLevelInterface(id domain.InterfaceIdentifier) error {
+	link, err := c.nl.LinkByName(string(id))
+	if err != nil {
+		var linkNotFoundError netlink.LinkNotFoundError
+		if errors.As(err, &linkNotFoundError) {
+			return nil // ignore not found error
+		}
+		return fmt.Errorf("unable to find low level interface: %w", err)
+	}
+
+	err = c.nl.LinkDel(link)
+	if err != nil {
+		return fmt.Errorf("failed to delete low level interface: %w", err)
+	}
+
+	return nil
+}
+
+func (c LocalController) SavePeer(
+	_ context.Context,
+	deviceId domain.InterfaceIdentifier,
+	id domain.PeerIdentifier,
+	updateFunc func(pp *domain.PhysicalPeer) (*domain.PhysicalPeer, error),
+) error {
+	physicalPeer, err := c.getOrCreatePeer(deviceId, id)
+	if err != nil {
+		return err
+	}
+
+	physicalPeer, err = updateFunc(physicalPeer)
+	if err != nil {
+		return err
+	}
+
+	// Check if the peer is disabled by looking at the backend extras
+	// For local controller, disabled peers should be deleted
+	if physicalPeer.GetExtras() != nil {
+		switch extras := physicalPeer.GetExtras().(type) {
+		case domain.LocalPeerExtras:
+			if extras.Disabled {
+				// Delete the peer instead of updating it
+				return c.deletePeer(deviceId, id)
+			}
+		}
+	}
+
+	if err := c.updatePeer(deviceId, physicalPeer); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (c LocalController) getOrCreatePeer(deviceId domain.InterfaceIdentifier, id domain.PeerIdentifier) (
+	*domain.PhysicalPeer,
+	error,
+) {
+	peer, err := c.getPeer(deviceId, id)
+	if err == nil {
+		return peer, nil // peer exists
+	}
+	if !errors.Is(err, os.ErrNotExist) {
+		return nil, fmt.Errorf("peer error: %w", err) // unknown error
+	}
+
+	// create new peer
+	err = c.wg.ConfigureDevice(string(deviceId), wgtypes.Config{
+		Peers: []wgtypes.PeerConfig{
+			{
+				PublicKey: id.ToPublicKey(),
+			},
+		},
+	})
+	if err != nil {
+		return nil, fmt.Errorf("peer create error for %s: %w", id.ToPublicKey(), err)
+	}
+
+	peer, err = c.getPeer(deviceId, id)
+	if err != nil {
+		return nil, fmt.Errorf("peer error after create: %w", err)
+	}
+	return peer, nil
+}
+
+func (c LocalController) getPeer(deviceId domain.InterfaceIdentifier, id domain.PeerIdentifier) (
+	*domain.PhysicalPeer,
+	error,
+) {
+	if !id.IsPublicKey() {
+		return nil, errors.New("invalid public key")
+	}
+
+	device, err := c.wg.Device(string(deviceId))
+	if err != nil {
+		return nil, err
+	}
+
+	publicKey := id.ToPublicKey()
+	for _, peer := range device.Peers {
+		if peer.PublicKey != publicKey {
+			continue
+		}
+
+		peerModel, err := c.convertWireGuardPeer(&peer)
+		return &peerModel, err
+	}
+
+	return nil, os.ErrNotExist
+}
+
+func (c LocalController) updatePeer(deviceId domain.InterfaceIdentifier, pp *domain.PhysicalPeer) error {
+	cfg := wgtypes.PeerConfig{
+		PublicKey:                   pp.GetPublicKey(),
+		Remove:                      false,
+		UpdateOnly:                  true,
+		PresharedKey:                pp.GetPresharedKey(),
+		Endpoint:                    pp.GetEndpointAddress(),
+		PersistentKeepaliveInterval: pp.GetPersistentKeepaliveTime(),
+		ReplaceAllowedIPs:           true,
+		AllowedIPs:                  pp.GetAllowedIPs(),
+	}
+
+	err := c.wg.ConfigureDevice(string(deviceId), wgtypes.Config{ReplacePeers: false, Peers: []wgtypes.PeerConfig{cfg}})
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (c LocalController) DeletePeer(
+	_ context.Context,
+	deviceId domain.InterfaceIdentifier,
+	id domain.PeerIdentifier,
+) error {
+	if !id.IsPublicKey() {
+		return errors.New("invalid public key")
+	}
+
+	err := c.deletePeer(deviceId, id)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (c LocalController) deletePeer(deviceId domain.InterfaceIdentifier, id domain.PeerIdentifier) error {
+	cfg := wgtypes.PeerConfig{
+		PublicKey: id.ToPublicKey(),
+		Remove:    true,
+	}
+
+	err := c.wg.ConfigureDevice(string(deviceId), wgtypes.Config{ReplacePeers: false, Peers: []wgtypes.PeerConfig{cfg}})
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// endregion wireguard-related
+
+// region wg-quick-related
+
+func (c LocalController) ExecuteInterfaceHook(id domain.InterfaceIdentifier, hookCmd string) error {
+	if hookCmd == "" {
+		return nil
+	}
+
+	slog.Debug("executing interface hook", "interface", id, "hook", hookCmd)
+	err := c.exec(hookCmd, id)
+	if err != nil {
+		return fmt.Errorf("failed to exec hook: %w", err)
+	}
+
+	return nil
+}
+
+func (c LocalController) SetDNS(id domain.InterfaceIdentifier, dnsStr, dnsSearchStr string) error {
+	if dnsStr == "" && dnsSearchStr == "" {
+		return nil
+	}
+
+	dnsServers := internal.SliceString(dnsStr)
+	dnsSearchDomains := internal.SliceString(dnsSearchStr)
+
+	dnsCommand := "resolvconf -a %resPref%i -m 0 -x"
+	dnsCommandInput := make([]string, 0, len(dnsServers)+len(dnsSearchDomains))
+
+	for _, dnsServer := range dnsServers {
+		dnsCommandInput = append(dnsCommandInput, fmt.Sprintf("nameserver %s", dnsServer))
+	}
+	for _, searchDomain := range dnsSearchDomains {
+		dnsCommandInput = append(dnsCommandInput, fmt.Sprintf("search %s", searchDomain))
+	}
+
+	err := c.exec(dnsCommand, id, dnsCommandInput...)
+	if err != nil {
+		return fmt.Errorf(
+			"failed to set dns settings (is resolvconf available?, for systemd create this symlink: ln -s /usr/bin/resolvectl /usr/local/bin/resolvconf): %w",
+			err,
+		)
+	}
+
+	return nil
+}
+
+func (c LocalController) UnsetDNS(id domain.InterfaceIdentifier) error {
+	dnsCommand := "resolvconf -d %resPref%i -f"
+
+	err := c.exec(dnsCommand, id)
+	if err != nil {
+		return fmt.Errorf("failed to unset dns settings: %w", err)
+	}
+
+	return nil
+}
+
+func (c LocalController) replaceCommandPlaceHolders(command string, interfaceId domain.InterfaceIdentifier) string {
+	command = strings.ReplaceAll(command, "%resPref", c.resolvConfIfacePrefix)
+	return strings.ReplaceAll(command, "%i", string(interfaceId))
+}
+
+func (c LocalController) exec(command string, interfaceId domain.InterfaceIdentifier, stdin ...string) error {
+	commandWithInterfaceName := c.replaceCommandPlaceHolders(command, interfaceId)
+	cmd := exec.Command(c.shellCmd, "-ce", commandWithInterfaceName)
+	if len(stdin) > 0 {
+		b := &bytes.Buffer{}
+		for _, ln := range stdin {
+			if _, err := fmt.Fprint(b, ln); err != nil {
+				return err
+			}
+		}
+		cmd.Stdin = b
+	}
+	out, err := cmd.CombinedOutput() // execute and wait for output
+	if err != nil {
+		return fmt.Errorf("failed to exexute shell command %s: %w", commandWithInterfaceName, err)
+	}
+	slog.Debug("executed shell command",
+		"command", commandWithInterfaceName,
+		"output", string(out))
+	return nil
+}
+
+// endregion wg-quick-related
+
+// region routing-related
+
+func (c LocalController) SyncRouteRules(_ context.Context, rules []domain.RouteRule) error {
+	// update fwmark rules
+	if err := c.setFwMarkRules(rules); err != nil {
+		return err
+	}
+
+	// update main rule
+	if err := c.setMainRule(rules); err != nil {
+		return err
+	}
+
+	// cleanup old main rules
+	if err := c.cleanupMainRule(rules); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (c LocalController) setFwMarkRules(rules []domain.RouteRule) error {
+	for _, rule := range rules {
+		existingRules, err := c.nl.RuleList(int(rule.IpFamily))
+		if err != nil {
+			return fmt.Errorf("failed to get existing rules for family %s: %w", rule.IpFamily, err)
+		}
+
+		ruleExists := false
+		for _, existingRule := range existingRules {
+			if rule.FwMark == existingRule.Mark && rule.Table == existingRule.Table {
+				ruleExists = true
+				break
+			}
+		}
+
+		if ruleExists {
+			continue // rule already exists, no need to recreate it
+		}
+
+		// create a missing rule
+		if err := c.nl.RuleAdd(&netlink.Rule{
+			Family:            int(rule.IpFamily),
+			Table:             rule.Table,
+			Mark:              rule.FwMark,
+			Invert:            true,
+			SuppressIfgroup:   -1,
+			SuppressPrefixlen: -1,
+			Priority:          c.getRulePriority(existingRules),
+			Mask:              nil,
+			Goto:              -1,
+			Flow:              -1,
+		}); err != nil {
+			return fmt.Errorf("failed to setup %s rule for fwmark %d and table %d: %w",
+				rule.IpFamily, rule.FwMark, rule.Table, err)
+		}
+	}
+	return nil
+}
+
+func (c LocalController) getRulePriority(existingRules []netlink.Rule) int {
+	prio := 32700 // linux main rule has a priority of 32766
+	for {
+		isFresh := true
+		for _, existingRule := range existingRules {
+			if existingRule.Priority == prio {
+				isFresh = false
+				break
+			}
+		}
+		if isFresh {
+			break
+		} else {
+			prio--
+		}
+	}
+	return prio
+}
+
+func (c LocalController) setMainRule(rules []domain.RouteRule) error {
+	var family domain.IpFamily
+	shouldHaveMainRule := false
+	for _, rule := range rules {
+		family = rule.IpFamily
+		if rule.HasDefault == true {
+			shouldHaveMainRule = true
+			break
+		}
+	}
+	if !shouldHaveMainRule {
+		return nil
+	}
+
+	existingRules, err := c.nl.RuleList(int(family))
+	if err != nil {
+		return fmt.Errorf("failed to get existing rules for family %s: %w", family, err)
+	}
+
+	ruleExists := false
+	for _, existingRule := range existingRules {
+		if existingRule.Table == unix.RT_TABLE_MAIN && existingRule.SuppressPrefixlen == 0 {
+			ruleExists = true
+			break
+		}
+	}
+
+	if ruleExists {
+		return nil // rule already exists, skip re-creation
+	}
+
+	if err := c.nl.RuleAdd(&netlink.Rule{
+		Family:            int(family),
+		Table:             unix.RT_TABLE_MAIN,
+		SuppressIfgroup:   -1,
+		SuppressPrefixlen: 0,
+		Priority:          c.getMainRulePriority(existingRules),
+		Mark:              0,
+		Mask:              nil,
+		Goto:              -1,
+		Flow:              -1,
+	}); err != nil {
+		return fmt.Errorf("failed to setup rule for main table: %w", err)
+	}
+
+	return nil
+}
+
+func (c LocalController) getMainRulePriority(existingRules []netlink.Rule) int {
+	priority := c.cfg.Advanced.RulePrioOffset
+	for {
+		isFresh := true
+		for _, existingRule := range existingRules {
+			if existingRule.Priority == priority {
+				isFresh = false
+				break
+			}
+		}
+		if isFresh {
+			break
+		} else {
+			priority++
+		}
+	}
+	return priority
+}
+
+func (c LocalController) cleanupMainRule(rules []domain.RouteRule) error {
+	var family domain.IpFamily
+	for _, rule := range rules {
+		family = rule.IpFamily
+		break
+	}
+
+	existingRules, err := c.nl.RuleList(int(family))
+	if err != nil {
+		return fmt.Errorf("failed to get existing rules for family %s: %w", family, err)
+	}
+
+	shouldHaveMainRule := false
+	for _, rule := range rules {
+		if rule.HasDefault == true {
+			shouldHaveMainRule = true
+			break
+		}
+	}
+
+	mainRules := 0
+	for _, existingRule := range existingRules {
+		if existingRule.Table == unix.RT_TABLE_MAIN && existingRule.SuppressPrefixlen == 0 {
+			mainRules++
+		}
+	}
+
+	removalCount := 0
+	if mainRules > 1 {
+		removalCount = mainRules - 1 // we only want one single rule
+	}
+	if !shouldHaveMainRule {
+		removalCount = mainRules
+	}
+
+	for _, existingRule := range existingRules {
+		if existingRule.Table == unix.RT_TABLE_MAIN && existingRule.SuppressPrefixlen == 0 {
+			if removalCount > 0 {
+				existingRule.Family = int(family) // set family, somehow the RuleList method does not populate the family field
+				if err := c.nl.RuleDel(&existingRule); err != nil {
+					return fmt.Errorf("failed to delete main rule: %w", err)
+				}
+				removalCount--
+			}
+		}
+	}
+
+	return nil
+}
+
+func (c LocalController) DeleteRouteRules(_ context.Context, rules []domain.RouteRule) error {
+	// TODO implement me
+	panic("implement me")
+}
+
+// endregion routing-related
+
+// region statistics-related
+
+func (c LocalController) PingAddresses(
+	ctx context.Context,
+	addr string,
+) (*domain.PingerResult, error) {
+	pinger, err := probing.NewPinger(addr)
+	if err != nil {
+		return nil, fmt.Errorf("failed to instantiate pinger for %s: %w", addr, err)
+	}
+
+	checkCount := 1
+	pinger.SetPrivileged(!c.cfg.Statistics.PingUnprivileged)
+	pinger.Count = checkCount
+	pinger.Timeout = 2 * time.Second
+	err = pinger.RunWithContext(ctx) // Blocks until finished.
+	if err != nil {
+		return nil, fmt.Errorf("failed to ping %s: %w", addr, err)
+	}
+
+	stats := pinger.Statistics()
+
+	return &domain.PingerResult{
+		PacketsRecv: stats.PacketsRecv,
+		PacketsSent: stats.PacketsSent,
+		Rtts:        stats.Rtts,
+	}, nil
+}
+
+// endregion statistics-related