142 lines
3.7 KiB
Go
142 lines
3.7 KiB
Go
// Copyright 2015 CoreOS, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package ip
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import (
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"crypto/rand"
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"fmt"
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"net"
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"os"
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"github.com/vishvananda/netlink"
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)
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func makeVethPair(name, peer string, mtu int) (netlink.Link, error) {
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veth := &netlink.Veth{
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LinkAttrs: netlink.LinkAttrs{
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Name: name,
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Flags: net.FlagUp,
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MTU: mtu,
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},
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PeerName: peer,
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}
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if err := netlink.LinkAdd(veth); err != nil {
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return nil, err
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}
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return veth, nil
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}
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func makeVeth(name string, mtu int) (peerName string, veth netlink.Link, err error) {
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for i := 0; i < 10; i++ {
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peerName, err = RandomVethName()
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if err != nil {
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return
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}
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veth, err = makeVethPair(name, peerName, mtu)
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switch {
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case err == nil:
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return
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case os.IsExist(err):
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continue
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default:
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err = fmt.Errorf("failed to make veth pair: %v", err)
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return
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}
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}
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// should really never be hit
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err = fmt.Errorf("failed to find a unique veth name")
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return
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}
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// RandomVethName returns string "veth" with random prefix (hashed from entropy)
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func RandomVethName() (string, error) {
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entropy := make([]byte, 4)
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_, err := rand.Reader.Read(entropy)
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if err != nil {
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return "", fmt.Errorf("failed to generate random veth name: %v", err)
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}
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// NetworkManager (recent versions) will ignore veth devices that start with "veth"
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return fmt.Sprintf("veth%x", entropy), nil
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}
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// SetupVeth creates the virtual ethernet pair and sets up the container's end in the container netns.
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// Setting up the host end up has to be done in the host netns outside of this function.
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// This is because moving the host veth end will cause it to be brought down automatically when it is moved to the host netns.
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func SetupVeth(contVethName string, mtu int, hostNS *os.File) (hostVeth, contVeth netlink.Link, err error) {
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var hostVethName string
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hostVethName, contVeth, err = makeVeth(contVethName, mtu)
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if err != nil {
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return
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}
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if err = netlink.LinkSetUp(contVeth); err != nil {
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err = fmt.Errorf("failed to set %q up: %v", contVethName, err)
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return
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}
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hostVeth, err = netlink.LinkByName(hostVethName)
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if err != nil {
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err = fmt.Errorf("failed to lookup %q: %v", hostVethName, err)
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return
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}
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if err = netlink.LinkSetNsFd(hostVeth, int(hostNS.Fd())); err != nil {
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err = fmt.Errorf("failed to move veth to host netns: %v", err)
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return
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}
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return
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}
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// DelLinkByName removes an interface link.
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func DelLinkByName(ifName string) error {
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iface, err := netlink.LinkByName(ifName)
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if err != nil {
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return fmt.Errorf("failed to lookup %q: %v", ifName, err)
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}
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if err = netlink.LinkDel(iface); err != nil {
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return fmt.Errorf("failed to delete %q: %v", ifName, err)
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}
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return nil
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}
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// DelLinkByNameAddr remove an interface returns its IP address
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// of the specified family
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func DelLinkByNameAddr(ifName string, family int) (*net.IPNet, error) {
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iface, err := netlink.LinkByName(ifName)
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if err != nil {
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return nil, fmt.Errorf("failed to lookup %q: %v", ifName, err)
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}
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addrs, err := netlink.AddrList(iface, family)
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if err != nil || len(addrs) == 0 {
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return nil, fmt.Errorf("failed to get IP addresses for %q: %v", ifName, err)
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}
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if err = netlink.LinkDel(iface); err != nil {
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return nil, fmt.Errorf("failed to delete %q: %v", ifName, err)
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}
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return addrs[0].IPNet, nil
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}
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