Unsafe route reload (#1083)

overlay/route.go

@@ -1,6 +1,7 @@
 package overlay
 
 import (
+	"bytes"
 	"fmt"
 	"math"
 	"net"
@@ -21,6 +22,35 @@ type Route struct {
 	Install bool
 }
 
+// Equal determines if a route that could be installed in the system route table is equal to another
+// Via is ignored since that is only consumed within nebula itself
+func (r Route) Equal(t Route) bool {
+	if !r.Cidr.IP.Equal(t.Cidr.IP) {
+		return false
+	}
+	if !bytes.Equal(r.Cidr.Mask, t.Cidr.Mask) {
+		return false
+	}
+	if r.Metric != t.Metric {
+		return false
+	}
+	if r.MTU != t.MTU {
+		return false
+	}
+	if r.Install != t.Install {
+		return false
+	}
+	return true
+}
+
+func (r Route) String() string {
+	s := r.Cidr.String()
+	if r.Metric != 0 {
+		s += fmt.Sprintf(" metric: %v", r.Metric)
+	}
+	return s
+}
+
 func makeRouteTree(l *logrus.Logger, routes []Route, allowMTU bool) (*cidr.Tree4[iputil.VpnIp], error) {
 	routeTree := cidr.NewTree4[iputil.VpnIp]()
 	for _, r := range routes {