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// 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/containernetworking/cni/pkg/utils/hwaddr"
"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 peerExists(name string) bool {
if _, err := netlink.LinkByName(name); err != nil {
return false
}
return true
}
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):
if peerExists(peerName) {
continue
}
err = fmt.Errorf("container veth name provided (%v) already exists", name)
return
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
}
func SetHWAddrByIP(ifName string, ip4 net.IP, ip6 net.IP) error {
iface, err := netlink.LinkByName(ifName)
if err != nil {
return fmt.Errorf("failed to lookup %q: %v", ifName, err)
}
switch {
case ip4 == nil && ip6 == nil:
return fmt.Errorf("neither ip4 or ip6 specified")
case ip4 != nil:
{
hwAddr, err := hwaddr.GenerateHardwareAddr4(ip4, hwaddr.PrivateMACPrefix)
if err != nil {
return fmt.Errorf("failed to generate hardware addr: %v", err)
}
if err = netlink.LinkSetHardwareAddr(iface, hwAddr); err != nil {
return fmt.Errorf("failed to add hardware addr to %q: %v", ifName, err)
}
}
case ip6 != nil:
// TODO: IPv6
}
return nil
}
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