[client] Refactor/iface pkg (#2646)

Refactor the flat code structure

client/iface/device/wg_link_linux.go

@@ -0,0 +1,133 @@
+//go:build linux && !android
+
+package device
+
+import (
+	"fmt"
+	"os"
+
+	log "github.com/sirupsen/logrus"
+	"github.com/vishvananda/netlink"
+)
+
+type wgLink struct {
+	attrs *netlink.LinkAttrs
+}
+
+func newWGLink(name string) *wgLink {
+	attrs := netlink.NewLinkAttrs()
+	attrs.Name = name
+
+	return &wgLink{
+		attrs: &attrs,
+	}
+}
+
+// Attrs returns the Wireguard's default attributes
+func (l *wgLink) Attrs() *netlink.LinkAttrs {
+	return l.attrs
+}
+
+// Type returns the interface type
+func (l *wgLink) Type() string {
+	return "wireguard"
+}
+
+// Close deletes the link interface
+func (l *wgLink) Close() error {
+	return netlink.LinkDel(l)
+}
+
+func (l *wgLink) recreate() error {
+	name := l.attrs.Name
+
+	// check if interface exists
+	link, err := netlink.LinkByName(name)
+	if err != nil {
+		switch err.(type) {
+		case netlink.LinkNotFoundError:
+			break
+		default:
+			return fmt.Errorf("link by name: %w", err)
+		}
+	}
+
+	// remove if interface exists
+	if link != nil {
+		err = netlink.LinkDel(l)
+		if err != nil {
+			return err
+		}
+	}
+
+	log.Debugf("adding device: %s", name)
+	err = netlink.LinkAdd(l)
+	if os.IsExist(err) {
+		log.Infof("interface %s already exists. Will reuse.", name)
+	} else if err != nil {
+		return fmt.Errorf("link add: %w", err)
+	}
+
+	return nil
+}
+
+func (l *wgLink) setMTU(mtu int) error {
+	if err := netlink.LinkSetMTU(l, mtu); err != nil {
+		log.Errorf("error setting MTU on interface: %s", l.attrs.Name)
+
+		return fmt.Errorf("link set mtu: %w", err)
+	}
+
+	return nil
+}
+
+func (l *wgLink) up() error {
+	if err := netlink.LinkSetUp(l); err != nil {
+		log.Errorf("error bringing up interface: %s", l.attrs.Name)
+		return fmt.Errorf("link setup: %w", err)
+	}
+
+	return nil
+}
+
+func (l *wgLink) assignAddr(address WGAddress) error {
+	//delete existing addresses
+	list, err := netlink.AddrList(l, 0)
+	if err != nil {
+		return fmt.Errorf("list addr: %w", err)
+	}
+
+	if len(list) > 0 {
+		for _, a := range list {
+			addr := a
+			err = netlink.AddrDel(l, &addr)
+			if err != nil {
+				return fmt.Errorf("del addr: %w", err)
+			}
+		}
+	}
+
+	name := l.attrs.Name
+	addrStr := address.String()
+
+	log.Debugf("adding address %s to interface: %s", addrStr, name)
+
+	addr, err := netlink.ParseAddr(addrStr)
+	if err != nil {
+		return fmt.Errorf("parse addr: %w", err)
+	}
+
+	err = netlink.AddrAdd(l, addr)
+	if os.IsExist(err) {
+		log.Infof("interface %s already has the address: %s", name, addrStr)
+	} else if err != nil {
+		return fmt.Errorf("add addr: %w", err)
+	}
+
+	// On linux, the link must be brought up
+	if err := netlink.LinkSetUp(l); err != nil {
+		return fmt.Errorf("link setup: %w", err)
+	}
+
+	return nil
+}