ip and mtu updates (linux only)

internal/wireguard/config.go

@@ -1,6 +1,7 @@
 package wireguard
 
 type Config struct {
-	DeviceName      string `yaml:"device" envconfig:"WG_DEVICE"`
-	WireGuardConfig string `yaml:"configFile" envconfig:"WG_CONFIG_FILE"` // optional, if set, updates will be written to this file
+	DeviceName        string `yaml:"device" envconfig:"WG_DEVICE"`
+	WireGuardConfig   string `yaml:"configFile" envconfig:"WG_CONFIG_FILE"`    // optional, if set, updates will be written to this file
+	ManageIPAddresses bool   `yaml:"manageIPAddresses" envconfig:"MANAGE_IPS"` // handle ip-address setup of interface
 }

internal/wireguard/net.go

@@ -0,0 +1,118 @@
+package wireguard
+
+import (
+	"fmt"
+	"net"
+
+	"github.com/milosgajdos/tenus"
+)
+
+func (m *Manager) GetIPAddress() ([]string, error) {
+	wgInterface, err := tenus.NewLinkFrom(m.Cfg.DeviceName)
+	if err != nil {
+		return nil, fmt.Errorf("could not retrieve WireGuard interface %s: %w", m.Cfg.DeviceName, err)
+	}
+
+	// Get golang net.interface
+	iface := wgInterface.NetInterface()
+	if iface == nil { // Not sure if this check is really necessary
+		return nil, fmt.Errorf("could not retrieve WireGuard net.interface: %w", err)
+	}
+
+	addrs, err := iface.Addrs()
+	if err != nil {
+		return nil, fmt.Errorf("could not retrieve WireGuard ip addresses: %w", err)
+	}
+
+	ipAddresses := make([]string, 0, len(addrs))
+	for _, addr := range addrs {
+		var ip net.IP
+		var mask net.IPMask
+		switch v := addr.(type) {
+		case *net.IPNet:
+			ip = v.IP
+			mask = v.Mask
+		case *net.IPAddr:
+			ip = v.IP
+			mask = ip.DefaultMask()
+		}
+		if ip == nil {
+			continue // something is wrong?
+		}
+
+		maskSize, _ := mask.Size()
+		cidr := fmt.Sprintf("%s/%d", ip.String(), maskSize)
+		ipAddresses = append(ipAddresses, cidr)
+	}
+
+	return ipAddresses, nil
+}
+
+func (m *Manager) SetIPAddress(cidrs []string) error {
+	wgInterface, err := tenus.NewLinkFrom(m.Cfg.DeviceName)
+	if err != nil {
+		return fmt.Errorf("could not retrieve WireGuard interface %s: %w", m.Cfg.DeviceName, err)
+	}
+
+	// First remove existing IP addresses
+	existingIPs, err := m.GetIPAddress()
+	if err != nil {
+		return err
+	}
+	for _, cidr := range existingIPs {
+		wgIp, wgIpNet, err := net.ParseCIDR(cidr)
+		if err != nil {
+			return fmt.Errorf("unable to parse cidr %s: %w", cidr, err)
+		}
+
+		if err := wgInterface.UnsetLinkIp(wgIp, wgIpNet); err != nil {
+			return fmt.Errorf("failed to unset ip %s: %w", cidr, err)
+		}
+	}
+
+	// Next set new IP adrresses
+	for _, cidr := range cidrs {
+		wgIp, wgIpNet, err := net.ParseCIDR(cidr)
+		if err != nil {
+			return fmt.Errorf("unable to parse cidr %s: %w", cidr, err)
+		}
+
+		if err := wgInterface.SetLinkIp(wgIp, wgIpNet); err != nil {
+			return fmt.Errorf("failed to set ip %s: %w", cidr, err)
+		}
+	}
+
+	return nil
+}
+
+func (m *Manager) GetMTU() (int, error) {
+	wgInterface, err := tenus.NewLinkFrom(m.Cfg.DeviceName)
+	if err != nil {
+		return 0, fmt.Errorf("could not retrieve WireGuard interface %s: %w", m.Cfg.DeviceName, err)
+	}
+
+	// Get golang net.interface
+	iface := wgInterface.NetInterface()
+	if iface == nil { // Not sure if this check is really necessary
+		return 0, fmt.Errorf("could not retrieve WireGuard net.interface: %w", err)
+	}
+
+	return iface.MTU, nil
+}
+
+func (m *Manager) SetMTU(mtu int) error {
+	wgInterface, err := tenus.NewLinkFrom(m.Cfg.DeviceName)
+	if err != nil {
+		return fmt.Errorf("could not retrieve WireGuard interface %s: %w", m.Cfg.DeviceName, err)
+	}
+
+	if mtu == 0 {
+		mtu = 1420 // WireGuard default MTU
+	}
+
+	if err := wgInterface.SetLinkMTU(mtu); err != nil {
+		return fmt.Errorf("could not set MTU on interface %s: %w", m.Cfg.DeviceName, err)
+	}
+
+	return nil
+}