enhancement: check default route during installation

pkg/console/install_panels.go

@@ -42,6 +42,7 @@ const (
 	ErrMsgVLANShouldBeANumberInRange string = "VLAN ID should be a number 1 ~ 4094."
 	ErrMsgMTUShouldBeANumber         string = "MTU should be a number."
 	NtpSettingName                   string = "ntp-servers"
+        ErrMsgNoDefaultRoute		 string = "No default route found. Please check the router setting on the DHCP server."
 )
 
 var (
@@ -1388,6 +1389,15 @@ func addNetworkPanel(c *Console) error {
 			mgmtNetwork.Gateway = ""
 			mgmtNetwork.MTU = 0
 		}
+
+		isDefaultRouteExist, err := checkDefaultRoute()
+		if err != nil {
+			return fmt.Sprintf("Failed to check default route: %s.", err.Error()), nil
+		}
+		if !isDefaultRouteExist {
+			return ErrMsgNoDefaultRoute, nil
+		}
+
 		return "", nil
 	}
 
@@ -2103,6 +2113,18 @@ func addInstallPanel(c *Console) error {
 				}
 			}
 
+			isDefaultRouteExist, err := checkDefaultRoute()
+			if err != nil {
+				logrus.Error(err)
+				printToPanel(c.Gui, "Failed to check default route.", installPanel)
+				return
+			}
+			if !isDefaultRouteExist {
+				logrus.Error(ErrMsgNoDefaultRoute)
+				printToPanel(c.Gui, ErrMsgNoDefaultRoute, installPanel)
+				return
+			}
+
 			// We need ForceGPT because cOS only supports ForceGPT (--force-gpt) flag, not ForceMBR!
 			c.config.ForceGPT = !c.config.ForceMBR
 

pkg/console/network.go

@@ -6,6 +6,7 @@ import (
 	"io/ioutil"
 	"os"
 	"os/exec"
+	"syscall"
 
 	yipSchema "github.com/mudler/yip/pkg/schema"
 	"github.com/sirupsen/logrus"
@@ -16,6 +17,24 @@ import (
 	"github.com/harvester/harvester-installer/pkg/config"
 )
 
+func checkDefaultRoute() (bool, error) {
+	routes, err := netlink.RouteList(nil, syscall.AF_INET)
+	if err != nil {
+		logrus.Errorf("Failed to list routes: %s", err.Error())
+		return false, err
+	}
+
+	defaultRouteExists := false
+	for _, route := range routes {
+		if route.Dst == nil {
+			defaultRouteExists = true
+			break
+		}
+	}
+
+	return defaultRouteExists, nil
+}
+
 func applyNetworks(network config.Network, hostname string) ([]byte, error) {
 	if err := config.RestoreOriginalNetworkConfig(); err != nil {
 		return nil, err