remove full iface access assumption

linux/bsd
fix #8

netroute_bsd.go

@@ -124,10 +124,7 @@ func New() (routing.Router, error) {
 	if err != nil {
 		return nil, err
 	}
-	for i, iface := range ifaces {
-		if i != iface.Index-1 {
-			return nil, fmt.Errorf("out of order iface %d = %v", i, iface)
-		}
+	for _, iface := range ifaces {
 		rtr.ifaces = append(rtr.ifaces, iface)
 		var addrs ipAddrs
 		ifaceAddrs, err := iface.Addrs()

netroute_linux.go

@@ -12,7 +12,6 @@
 package netroute
 
 import (
-	"fmt"
 	"net"
 	"sort"
 	"syscall"
@@ -83,10 +82,7 @@ loop:
 	if err != nil {
 		return nil, err
 	}
-	for i, iface := range ifaces {
-		if i != iface.Index-1 {
-			return nil, fmt.Errorf("out of order iface %d = %v", i, iface)
-		}
+	for _, iface := range ifaces {
 		rtr.ifaces = append(rtr.ifaces, iface)
 		var addrs ipAddrs
 		ifaceAddrs, err := iface.Addrs()