[WIP] Add initial utilities for link and namespace actions

This change introduces basic utilities for managing interfaces,
routes, and namespaces. See
#2

Signed-off-by: Ryan Tidwell <[email protected]>

go.mod

@@ -3,4 +3,6 @@ module github.com/networkservicemesh/sdk-kernel
 go 1.13
 
 require (
+  github.com/vishvananda/netlink v1.0.0
+  github.com/vishvananda/netns v0.0.0-20190625233234-7109fa855b0f
 )

pkg/networkservice/kernelutils/common.go

@@ -0,0 +1,89 @@
+// Copyright 2019 SUSE LLC.
+// SPDX-License-Identifier: Apache-2.0
+//
+// 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 kernelutils
+
+import (
+	"github.com/networkservicemesh/networkservicemesh/controlplane/api/connectioncontext"
+
+  "net"
+
+  "github.com/sirupsen/logrus"
+  "github.com/vishvananda/netlink"
+)
+
+// Kernel forwarding plane related constants
+const (
+	cLOCAL    = iota
+	cINCOMING = iota
+	cOUTGOING = iota
+)
+
+const (
+	/* VETH pairs are used only for local connections(same node), so we can use a larger MTU size as there's no multi-node connection */
+	cVETHMTU    = 16000
+	cCONNECT    = true
+	cDISCONNECT = false
+)
+
+type connectionConfig struct {
+	id            string
+	srcNetNsInode string
+	dstNetNsInode string
+	srcName       string
+	dstName       string
+	srcIP         string
+	dstIP         string
+	srcIPVXLAN    net.IP
+	dstIPVXLAN    net.IP
+	srcRoutes     []*connectioncontext.Route
+	dstRoutes     []*connectioncontext.Route
+	neighbors     []*connectioncontext.IpNeighbor
+	vni           int
+}
+
+// addNeighbors adds neighbors
+func AddNeighbors(link netlink.Link, neighbors []*connectioncontext.IpNeighbor) error {
+	for _, neighbor := range neighbors {
+		mac, err := net.ParseMAC(neighbor.GetHardwareAddress())
+		if err != nil {
+			logrus.Error("common: failed parsing the MAC address for IP neighbors:", err)
+			return err
+		}
+		neigh := netlink.Neigh{
+			LinkIndex:    link.Attrs().Index,
+			State:        0x02, // netlink.NUD_REACHABLE, // the constant is somehow not being found in the package in case of using a darwin based machine
+			IP:           net.ParseIP(neighbor.GetIp()),
+			HardwareAddr: mac,
+		}
+		if err = netlink.NeighAdd(&neigh); err != nil {
+			logrus.Error("common: failed adding neighbor:", err)
+			return err
+		}
+	}
+	return nil
+}
+
+// newVETH returns a VETH interface instance
+func NewVETH(srcName, dstName string) *netlink.Veth {
+	/* Populate the VETH interface configuration */
+	return &netlink.Veth{
+		LinkAttrs: netlink.LinkAttrs{
+			Name: srcName,
+			MTU:  cVETHMTU,
+		},
+		PeerName: dstName,
+	}
+}

pkg/networkservice/kernelutils/namespaceutils.go

@@ -0,0 +1,37 @@
+// Copyright 2019 SUSE LLC.
+// SPDX-License-Identifier: Apache-2.0
+//
+// 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 kernelutils
+
+import (
+  "github.com/sirupsen/logrus"
+  "github.com/vishvananda/netlink"
+  "github.com/vishvananda/netns"
+)
+
+func InjectLinkInNamespace(containerNs netns.NsHandle, ifaceName string) error {
+  /* Get a link object for the interface */
+  ifaceLink, err := netlink.LinkByName(ifaceName)
+  if err != nil {
+    logrus.Errorf("common: failed to get link for %q - %v", ifaceName, err)
+    return err
+  }
+  /* Inject the interface into the desired namespace */
+  if err = netlink.LinkSetNsFd(ifaceLink, int(containerNs)); err != nil {
+    logrus.Errorf("common: failed to inject %q in namespace - %v", ifaceName, err)
+    return err
+  }
+  return nil
+}

test/integration/namespace_utils_test.go

@@ -0,0 +1,49 @@
+package sdk_kernel_tests
+
+import (
+	"testing"
+
+  . "github.com/onsi/gomega"
+
+  "github.com/networkservicemesh/sdk-kernel/pkg/networkservice/kernelutils"
+
+  "github.com/sirupsen/logrus"
+  "github.com/vishvananda/netlink"
+  "github.com/vishvananda/netns"
+)
+
+const testVethSrcName = "sdk-kernel-src"
+const testVethDstName = "sdk-kernel-dst"
+
+func TestInjectLinkInNamespace(t *testing.T) {
+  g := NewWithT(t)
+
+  // set up the basic resources for the test
+  currns, _ := netns.Get()
+  testns, _ := netns.New()
+  _ = netns.Set(currns)
+  vethErr := netlink.LinkAdd(kernelutils.NewVETH(testVethSrcName, testVethDstName))
+  g.Expect(vethErr).To(BeNil())
+
+  // clean up after ourselves
+  defer func(rootns netns.NsHandle, testns netns.NsHandle, veth *netlink.Veth) {
+    _ = netns.Set(rootns)
+    testns.Close()
+    netlink.LinkDel(veth)
+  }(currns, testns, kernelutils.NewVETH(testVethSrcName, testVethDstName))
+
+  // move one end of the veth into testns and run assertions
+  injectError := kernelutils.InjectLinkInNamespace(testns, testVethDstName)
+
+  _ = netns.Set(testns)
+  nsLinks, _ := netlink.LinkList()
+  _, linkErr := netlink.LinkByName(testVethDstName)
+
+  // assert no error on link injection
+  g.Expect(injectError).To(BeNil())
+  // assert only loopback and the interface we inject exist in the namespace
+  g.Expect(len(nsLinks)).To(Equal(2))
+  g.Expect(linkErr).To(BeNil())
+
+	logrus.Printf("Done")
+}