From 1d4c21dec9596e0fcacad2b84859261b312ac00e Mon Sep 17 00:00:00 2001
From: "Jason A. Donenfeld" <Jason@zx2c4.com>
Date: Mon, 4 Mar 2019 03:04:22 +0100
Subject: ifaceconfig: deduplicate routes

---
 service/ifaceconfig.go | 49 +++++++++++++++++++++++++++++++------------------
 1 file changed, 31 insertions(+), 18 deletions(-)

(limited to 'service')

diff --git a/service/ifaceconfig.go b/service/ifaceconfig.go
index eda8fdb0..c6a8257d 100644
--- a/service/ifaceconfig.go
+++ b/service/ifaceconfig.go
@@ -6,6 +6,7 @@
 package service
 
 import (
+	"bytes"
 	"encoding/binary"
 	"errors"
 	"golang.org/x/sys/windows"
@@ -13,7 +14,7 @@ import (
 	"golang.zx2c4.com/wireguard/device"
 	"golang.zx2c4.com/wireguard/windows/conf"
 	"net"
-	"os"
+	"sort"
 	"unsafe"
 )
 
@@ -157,25 +158,37 @@ func configureInterface(conf *conf.Config, guid *windows.GUID) error {
 		return err
 	}
 
-	err = iface.FlushRoutes()
-	if err != nil {
-		return nil
-	}
-	for _, route := range routes {
-		err = iface.AddRoute(&route, false)
-
-		//TODO: Ignoring duplicate errors like this maybe isn't very reasonable.
-		// instead we should make sure we're not adding duplicates ourselves when
-		// inserting the gateway routes.
-		if syserr, ok := err.(*os.SyscallError); ok {
-			if syserr.Err == windows.Errno(ERROR_OBJECT_ALREADY_EXISTS) {
-				err = nil
-			}
+	deduplicatedRoutes := make([]*winipcfg.RouteData, routeCount)
+	routeCount = 0
+	sort.Slice(routes, func(i, j int) bool {
+		if routes[i].Metric < routes[j].Metric {
+			return true
 		}
-
-		if err != nil {
-			return err
+		if bytes.Compare(routes[i].NextHop, routes[j].NextHop) == -1 {
+			return true
+		}
+		if bytes.Compare(routes[i].Destination.IP, routes[j].Destination.IP) == -1 {
+			return true
 		}
+		if bytes.Compare(routes[i].Destination.Mask, routes[j].Destination.Mask) == -1 {
+			return true
+		}
+		return false
+	})
+	for i := 0; i < len(routes); i++ {
+		if i > 0 && routes[i].Metric == routes[i - 1].Metric &&
+			bytes.Equal(routes[i].NextHop, routes[i - 1].NextHop) &&
+			bytes.Equal(routes[i].Destination.IP, routes[i - 1].Destination.IP) &&
+			bytes.Equal(routes[i].Destination.Mask, routes[i - 1].Destination.Mask) {
+			continue
+		}
+		deduplicatedRoutes[routeCount] = &routes[i]
+		routeCount++
+	}
+
+	err = iface.SetRoutes(deduplicatedRoutes, false)
+	if err != nil {
+		return nil
 	}
 
 	err = iface.SetDNS(conf.Interface.Dns)
-- 
cgit v1.2.3-59-g8ed1b