From 9523ca624ac9157e11ead8bbd91ea63199d4f8e4 Mon Sep 17 00:00:00 2001
From: Leo Antunes <leo@costela.net>
Date: Sun, 14 Jul 2019 12:59:54 +0200
Subject: [PATCH] reuse existing interface instead of erroring out

---
 tests/entrypoint.sh |  2 --
 wireguard.go        | 18 ++----------------
 2 files changed, 2 insertions(+), 18 deletions(-)

diff --git a/tests/entrypoint.sh b/tests/entrypoint.sh
index a37e223..ff641e7 100755
--- a/tests/entrypoint.sh
+++ b/tests/entrypoint.sh
@@ -6,7 +6,5 @@ mkdir -p /dev/net
 mknod /dev/net/tun c 10 200
 
 wireguard-go wgoverlay
-# this disables kernel-mode interface creation; see wireguard.go:createWgInterface()
-export WESHER_E2E_TESTS=1
 
 /app/wesher --log-level debug --cluster-key 'ILICZ3yBMCGAWNIq5Pn0bewBVimW3Q2yRVJ/Be+b1Uc=' "$@"
\ No newline at end of file
diff --git a/wireguard.go b/wireguard.go
index a823696..7556b61 100644
--- a/wireguard.go
+++ b/wireguard.go
@@ -77,8 +77,8 @@ func (wg *wgState) downInterface() error {
 }
 
 func (wg *wgState) setUpInterface(nodes []node) error {
-	if err := wg.createWgInterface(); err != nil {
-		return err
+	if err := netlink.LinkAdd(&wireguard{LinkAttrs: netlink.LinkAttrs{Name: wg.iface}}); err != nil && !os.IsExist(err) {
+		return errors.Wrapf(err, "could not create interface %s", wg.iface)
 	}
 
 	peerCfgs, err := wg.nodesToPeerConfigs(nodes)
@@ -133,17 +133,3 @@ func (wg *wgState) nodesToPeerConfigs(nodes []node) ([]wgtypes.PeerConfig, error
 	}
 	return peerCfgs, nil
 }
-
-func (wg *wgState) createWgInterface() error {
-	if _, err := wg.client.Device(wg.iface); err == nil {
-		// device already exists, but we are running e2e tests, so we're using the user-mode implementation
-		// see tests/entrypoint.sh
-		if _, e2e := os.LookupEnv("WESHER_E2E_TESTS"); e2e {
-			return nil
-		}
-	}
-	if err := netlink.LinkAdd(&wireguard{LinkAttrs: netlink.LinkAttrs{Name: wg.iface}}); err != nil {
-		return errors.Wrapf(err, "could not create interface %s", wg.iface)
-	}
-	return nil
-}