From 3358f16dd6cf2e4150833baed870bd7e91f401b8 Mon Sep 17 00:00:00 2001
From: Gabe Rosenhouse <grosenhouse@pivotal.io>
Date: Sun, 17 Apr 2016 18:28:10 -0700
Subject: [PATCH] Extract testhelpers from loopback test suite

---
 testhelpers/testhelpers.go | 69 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 69 insertions(+)
 create mode 100644 testhelpers/testhelpers.go

diff --git a/testhelpers/testhelpers.go b/testhelpers/testhelpers.go
new file mode 100644
index 00000000..f1ccb24e
--- /dev/null
+++ b/testhelpers/testhelpers.go
@@ -0,0 +1,69 @@
+// Copyright 2016 CNI authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package testhelpers
+
+import (
+	"fmt"
+	"os"
+	"runtime"
+
+	"golang.org/x/sys/unix"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+func MakeNetworkNS(containerID string) string {
+	namespace := "/var/run/netns/" + containerID
+	pid := unix.Getpid()
+	tid := unix.Gettid()
+
+	err := os.MkdirAll("/var/run/netns", 0600)
+	Expect(err).NotTo(HaveOccurred())
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+	go (func() {
+		defer GinkgoRecover()
+
+		err = unix.Unshare(unix.CLONE_NEWNET)
+		Expect(err).NotTo(HaveOccurred())
+
+		fd, err := os.Create(namespace)
+		Expect(err).NotTo(HaveOccurred())
+		defer fd.Close()
+
+		err = unix.Mount("/proc/self/ns/net", namespace, "none", unix.MS_BIND, "")
+		Expect(err).NotTo(HaveOccurred())
+	})()
+
+	Eventually(namespace).Should(BeAnExistingFile())
+
+	fd, err := unix.Open(fmt.Sprintf("/proc/%d/task/%d/ns/net", pid, tid), unix.O_RDONLY, 0)
+	Expect(err).NotTo(HaveOccurred())
+
+	defer unix.Close(fd)
+
+	_, _, e1 := unix.Syscall(unix.SYS_SETNS, uintptr(fd), uintptr(unix.CLONE_NEWNET), 0)
+	Expect(e1).To(BeZero())
+
+	return namespace
+}
+
+func RemoveNetworkNS(networkNS string) error {
+	err := unix.Unmount(networkNS, unix.MNT_DETACH)
+
+	err = os.RemoveAll(networkNS)
+	return err
+}