From 6fe247ec07925d00586f8573a901a6efc019f327 Mon Sep 17 00:00:00 2001
From: Maycon Santos <mlsmaycon@gmail.com>
Date: Mon, 13 May 2024 11:32:29 +0200
Subject: [PATCH] validate-mtu, nexthop and tun address config

---
 client/internal/routemanager/client.go    | 6 ++++++
 client/internal/routemanager/systemops.go | 9 +++++++--
 iface/iface.go                            | 2 +-
 iface/tun_darwin.go                       | 5 ++++-
 4 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/client/internal/routemanager/client.go b/client/internal/routemanager/client.go
index e82f4b1da..7d6314aeb 100644
--- a/client/internal/routemanager/client.go
+++ b/client/internal/routemanager/client.go
@@ -261,6 +261,12 @@ func (c *clientNetwork) recalculateRouteAndUpdatePeerAndSystem() error {
 			return fmt.Errorf("remove route from peer: %v", err)
 		}
 	} else {
+		if c.network == netip.MustParsePrefix("0.0.0.0/0") {
+			s, err := c.statusRecorder.GetPeer(c.routes[chosen].Peer)
+			if err == nil && s.IP != "" {
+				exitIP = netip.MustParseAddr(s.IP)
+			}
+		}
 		// otherwise add the route to the system
 		if err := addVPNRoute(c.network, c.getAsInterface()); err != nil {
 			return fmt.Errorf("route %s couldn't be added for peer %s, err: %v",
diff --git a/client/internal/routemanager/systemops.go b/client/internal/routemanager/systemops.go
index c7baead48..beca0419b 100644
--- a/client/internal/routemanager/systemops.go
+++ b/client/internal/routemanager/systemops.go
@@ -29,6 +29,7 @@ var ErrRouteNotFound = errors.New("route not found")
 var ErrRouteNotAllowed = errors.New("route not allowed")
 
 var tunIP netip.Addr
+var exitIP netip.Addr
 
 // TODO: fix: for default our wg address now appears as the default gw
 func addRouteForCurrentDefaultGateway(prefix netip.Prefix) error {
@@ -198,10 +199,14 @@ func addRouteToNonVPNIntf(prefix netip.Prefix, vpnIntf *iface.WGIface, initialNe
 // in two /1 prefixes to avoid replacing the existing default route
 func genericAddVPNRoute(prefix netip.Prefix, intf *net.Interface) error {
 	if prefix == defaultv4 {
-		if err := addToRouteTable(splitDefaultv4_1, tunIP, intf); err != nil {
+		ip := tunIP
+		if exitIP.IsValid() {
+			ip = exitIP
+		}
+		if err := addToRouteTable(splitDefaultv4_1, ip, intf); err != nil {
 			return err
 		}
-		if err := addToRouteTable(splitDefaultv4_2, tunIP, intf); err != nil {
+		if err := addToRouteTable(splitDefaultv4_2, ip, intf); err != nil {
 			if err2 := removeFromRouteTable(splitDefaultv4_1, netip.Addr{}, intf); err2 != nil {
 				log.Warnf("Failed to rollback route addition: %s", err2)
 			}
diff --git a/iface/iface.go b/iface/iface.go
index 3ae40ad4c..da72cb30a 100644
--- a/iface/iface.go
+++ b/iface/iface.go
@@ -13,7 +13,7 @@ import (
 )
 
 const (
-	DefaultMTU    = 1280
+	DefaultMTU    = 1420
 	DefaultWgPort = 51820
 )
 
diff --git a/iface/tun_darwin.go b/iface/tun_darwin.go
index bac14986f..408a520de 100644
--- a/iface/tun_darwin.go
+++ b/iface/tun_darwin.go
@@ -4,6 +4,7 @@
 package iface
 
 import (
+	"net/netip"
 	"os/exec"
 
 	"github.com/pion/transport/v3"
@@ -119,7 +120,9 @@ func (t *tunDevice) Wrapper() *DeviceWrapper {
 
 // assignAddr Adds IP address to the tunnel interface and network route based on the range provided
 func (t *tunDevice) assignAddr() error {
-	cmd := exec.Command("ifconfig", t.name, "inet", t.address.IP.String(), t.address.IP.String())
+	np := netip.MustParseAddr(t.address.IP.String())
+
+	cmd := exec.Command("ifconfig", t.name, "inet", t.address.IP.String(), np.Prev().String())
 	if out, err := cmd.CombinedOutput(); err != nil {
 		log.Infof(`adding address command "%v" failed with output %s and error: `, cmd.String(), out)
 		return err