Push route handling into overlay, a few more nits fixed (#581)

overlay/tun.go

@@ -1,15 +1,30 @@
 package overlay
 
 import (
+	"fmt"
 	"net"
+	"runtime"
 
 	"github.com/sirupsen/logrus"
+	"github.com/slackhq/nebula/cidr"
 	"github.com/slackhq/nebula/config"
+	"github.com/slackhq/nebula/util"
 )
 
 const DefaultMTU = 1300
 
-func NewDeviceFromConfig(c *config.C, l *logrus.Logger, tunCidr *net.IPNet, routes, unsafeRoutes []Route, fd *int, routines int) (Device, error) {
+func NewDeviceFromConfig(c *config.C, l *logrus.Logger, tunCidr *net.IPNet, fd *int, routines int) (Device, error) {
+	routes, err := parseRoutes(c, tunCidr)
+	if err != nil {
+		return nil, util.NewContextualError("Could not parse tun.routes", nil, err)
+	}
+
+	unsafeRoutes, err := parseUnsafeRoutes(c, tunCidr)
+	if err != nil {
+		return nil, util.NewContextualError("Could not parse tun.unsafe_routes", nil, err)
+	}
+	routes = append(routes, unsafeRoutes...)
+
 	switch {
 	case c.GetBool("tun.disabled", false):
 		tun := newDisabledTun(tunCidr, c.GetInt("tun.tx_queue", 500), c.GetBool("stats.message_metrics", false), l)
@@ -22,7 +37,6 @@ func NewDeviceFromConfig(c *config.C, l *logrus.Logger, tunCidr *net.IPNet, rout
 			tunCidr,
 			c.GetInt("tun.mtu", DefaultMTU),
 			routes,
-			unsafeRoutes,
 			c.GetInt("tun.tx_queue", 500),
 		)
 
@@ -33,9 +47,22 @@ func NewDeviceFromConfig(c *config.C, l *logrus.Logger, tunCidr *net.IPNet, rout
 			tunCidr,
 			c.GetInt("tun.mtu", DefaultMTU),
 			routes,
-			unsafeRoutes,
 			c.GetInt("tun.tx_queue", 500),
 			routines > 1,
 		)
 	}
 }
+
+func makeCidrTree(routes []Route, allowMTU bool) (*cidr.Tree4, error) {
+	cidrTree := cidr.NewTree4()
+	for _, r := range routes {
+		if !allowMTU && r.MTU > 0 {
+			return nil, fmt.Errorf("route MTU is not supported in %s", runtime.GOOS)
+		}
+
+		if r.Via != nil {
+			cidrTree.AddCIDR(r.Cidr, r.Via)
+		}
+	}
+	return cidrTree, nil
+}