Add CNI networking to system-docker

vendor/github.com/containernetworking/cni/pkg/ip/link.go

@@ -0,0 +1,153 @@
+// Copyright 2015 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 ip
+
+import (
+	"crypto/rand"
+	"fmt"
+	"net"
+	"os"
+
+	"github.com/containernetworking/cni/pkg/ns"
+	"github.com/vishvananda/netlink"
+)
+
+func makeVethPair(name, peer string, mtu int) (netlink.Link, error) {
+	veth := &netlink.Veth{
+		LinkAttrs: netlink.LinkAttrs{
+			Name:  name,
+			Flags: net.FlagUp,
+			MTU:   mtu,
+		},
+		PeerName: peer,
+	}
+	if err := netlink.LinkAdd(veth); err != nil {
+		return nil, err
+	}
+
+	return veth, nil
+}
+
+func makeVeth(name string, mtu int) (peerName string, veth netlink.Link, err error) {
+	for i := 0; i < 10; i++ {
+		peerName, err = RandomVethName()
+		if err != nil {
+			return
+		}
+
+		veth, err = makeVethPair(name, peerName, mtu)
+		switch {
+		case err == nil:
+			return
+
+		case os.IsExist(err):
+			continue
+
+		default:
+			err = fmt.Errorf("failed to make veth pair: %v", err)
+			return
+		}
+	}
+
+	// should really never be hit
+	err = fmt.Errorf("failed to find a unique veth name")
+	return
+}
+
+// RandomVethName returns string "veth" with random prefix (hashed from entropy)
+func RandomVethName() (string, error) {
+	entropy := make([]byte, 4)
+	_, err := rand.Reader.Read(entropy)
+	if err != nil {
+		return "", fmt.Errorf("failed to generate random veth name: %v", err)
+	}
+
+	// NetworkManager (recent versions) will ignore veth devices that start with "veth"
+	return fmt.Sprintf("veth%x", entropy), nil
+}
+
+// SetupVeth sets up a virtual ethernet link.
+// Should be in container netns, and will switch back to hostNS to set the host
+// veth end up.
+func SetupVeth(contVethName string, mtu int, hostNS ns.NetNS) (hostVeth, contVeth netlink.Link, err error) {
+	var hostVethName string
+	hostVethName, contVeth, err = makeVeth(contVethName, mtu)
+	if err != nil {
+		return
+	}
+
+	if err = netlink.LinkSetUp(contVeth); err != nil {
+		err = fmt.Errorf("failed to set %q up: %v", contVethName, err)
+		return
+	}
+
+	hostVeth, err = netlink.LinkByName(hostVethName)
+	if err != nil {
+		err = fmt.Errorf("failed to lookup %q: %v", hostVethName, err)
+		return
+	}
+
+	if err = netlink.LinkSetNsFd(hostVeth, int(hostNS.Fd())); err != nil {
+		err = fmt.Errorf("failed to move veth to host netns: %v", err)
+		return
+	}
+
+	err = hostNS.Do(func(_ ns.NetNS) error {
+		hostVeth, err := netlink.LinkByName(hostVethName)
+		if err != nil {
+			return fmt.Errorf("failed to lookup %q in %q: %v", hostVethName, hostNS.Path(), err)
+		}
+
+		if err = netlink.LinkSetUp(hostVeth); err != nil {
+			return fmt.Errorf("failed to set %q up: %v", hostVethName, err)
+		}
+		return nil
+	})
+	return
+}
+
+// DelLinkByName removes an interface link.
+func DelLinkByName(ifName string) error {
+	iface, err := netlink.LinkByName(ifName)
+	if err != nil {
+		return fmt.Errorf("failed to lookup %q: %v", ifName, err)
+	}
+
+	if err = netlink.LinkDel(iface); err != nil {
+		return fmt.Errorf("failed to delete %q: %v", ifName, err)
+	}
+
+	return nil
+}
+
+// DelLinkByNameAddr remove an interface returns its IP address
+// of the specified family
+func DelLinkByNameAddr(ifName string, family int) (*net.IPNet, error) {
+	iface, err := netlink.LinkByName(ifName)
+	if err != nil {
+		return nil, fmt.Errorf("failed to lookup %q: %v", ifName, err)
+	}
+
+	addrs, err := netlink.AddrList(iface, family)
+	if err != nil || len(addrs) == 0 {
+		return nil, fmt.Errorf("failed to get IP addresses for %q: %v", ifName, err)
+	}
+
+	if err = netlink.LinkDel(iface); err != nil {
+		return nil, fmt.Errorf("failed to delete %q: %v", ifName, err)
+	}
+
+	return addrs[0].IPNet, nil
+}