Maint: pass only single strings to logger methods

- Do not assume formatting from logger's interface
- Allow to change golibs in the future to accept only strings for logger methods

internal/firewall/outboundsubnets.go

@@ -37,7 +37,7 @@ func (c *configurator) removeOutboundSubnets(ctx context.Context, subnets []net.
 	const remove = true
 	for _, subnet := range subnets {
 		if err := c.acceptOutputFromIPToSubnet(ctx, c.defaultInterface, c.localIP, subnet, remove); err != nil {
-			c.logger.Error("cannot remove outdated outbound subnet through firewall: %s", err)
+			c.logger.Error("cannot remove outdated outbound subnet through firewall: " + err.Error())
 			continue
 		}
 		c.outboundSubnets = removeSubnetFromSubnets(c.outboundSubnets, subnet)

internal/firewall/ports.go

@@ -3,6 +3,7 @@ package firewall
 import (
 	"context"
 	"fmt"
+	"strconv"
 )
 
 func (c *configurator) SetAllowedPort(ctx context.Context, port uint16, intf string) (err error) {
@@ -19,7 +20,7 @@ func (c *configurator) SetAllowedPort(ctx context.Context, port uint16, intf str
 		return nil
 	}
 
-	c.logger.Info("setting allowed input port %d through interface %s...", port, intf)
+	c.logger.Info("setting allowed input port " + fmt.Sprint(port) + " through interface " + intf + "...")
 
 	if existingIntf, ok := c.allowedInputPorts[port]; ok {
 		if intf == existingIntf {
@@ -54,7 +55,7 @@ func (c *configurator) RemoveAllowedPort(ctx context.Context, port uint16) (err
 		return nil
 	}
 
-	c.logger.Info("removing allowed port %d through firewall...", port)
+	c.logger.Info("removing allowed port "+strconv.Itoa(int(port))+" through firewall...", port)
 
 	intf, ok := c.allowedInputPorts[port]
 	if !ok {

internal/firewall/vpn.go

@@ -26,7 +26,7 @@ func (c *configurator) SetVPNConnection(ctx context.Context, connection models.O
 	remove := true
 	if c.vpnConnection.IP != nil {
 		if err := c.acceptOutputTrafficToVPN(ctx, c.defaultInterface, c.vpnConnection, remove); err != nil {
-			c.logger.Error("cannot remove outdated VPN connection through firewall: %s", err)
+			c.logger.Error("cannot remove outdated VPN connection through firewall: " + err.Error())
 		}
 	}
 	c.vpnConnection = models.OpenVPNConnection{}