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netlink.go
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netlink.go
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// Copyright 2017-2018 Authors of Cilium
//
// 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 loader
import (
"context"
"fmt"
"net"
"github.com/cilium/cilium/pkg/bpf"
"github.com/cilium/cilium/pkg/command/exec"
"github.com/cilium/cilium/pkg/defaults"
"github.com/cilium/cilium/pkg/mac"
"github.com/cilium/cilium/pkg/option"
"github.com/cilium/cilium/pkg/sysctl"
"github.com/vishvananda/netlink"
)
type baseDeviceMode string
const (
ipvlanMode = baseDeviceMode("ipvlan")
directMode = baseDeviceMode("direct")
tunnelMode = baseDeviceMode("tunnel")
libbpfFixupMsg = "struct bpf_elf_map fixup performed due to size mismatch!"
)
func replaceQdisc(ifName string) error {
link, err := netlink.LinkByName(ifName)
if err != nil {
return err
}
attrs := netlink.QdiscAttrs{
LinkIndex: link.Attrs().Index,
Handle: netlink.MakeHandle(0xffff, 0),
Parent: netlink.HANDLE_CLSACT,
}
qdisc := &netlink.GenericQdisc{
QdiscAttrs: attrs,
QdiscType: "clsact",
}
if err = netlink.QdiscReplace(qdisc); err != nil {
return fmt.Errorf("netlink: Replacing qdisc for %s failed: %s", ifName, err)
} else {
log.Debugf("netlink: Replacing qdisc for %s succeeded", ifName)
}
return nil
}
// replaceDatapath the qdisc and BPF program for a endpoint or XDP program.
func replaceDatapath(ctx context.Context, ifName, objPath, progSec, progDirection string, xdp bool, xdpMode string) error {
var (
err error
loaderProg string
args []string
)
if !xdp {
if err = replaceQdisc(ifName); err != nil {
return fmt.Errorf("Failed to replace Qdisc for %s: %s", ifName, err)
}
}
// FIXME: Replace cilium-map-migrate with Golang map migration
cmd := exec.CommandContext(ctx, "cilium-map-migrate", "-s", objPath)
cmd.Env = bpf.Environment()
if _, err = cmd.CombinedOutput(log, true); err != nil {
return err
}
defer func() {
var retCode string
if err == nil {
retCode = "0"
} else {
retCode = "1"
}
args := []string{"-e", objPath, "-r", retCode}
cmd := exec.CommandContext(ctx, "cilium-map-migrate", args...)
cmd.Env = bpf.Environment()
_, _ = cmd.CombinedOutput(log, true) // ignore errors
}()
// FIXME: replace exec with native call
if xdp {
loaderProg = "ip"
args = []string{"-force", "link", "set", "dev", ifName, xdpMode,
"obj", objPath, "sec", progSec}
} else {
loaderProg = "tc"
args = []string{"filter", "replace", "dev", ifName, progDirection,
"prio", "1", "handle", "1", "bpf", "da", "obj", objPath,
"sec", progSec,
}
}
cmd = exec.CommandContext(ctx, loaderProg, args...).WithFilters(libbpfFixupMsg)
_, err = cmd.CombinedOutput(log, true)
if err != nil {
return fmt.Errorf("Failed to load prog with %s: %w", loaderProg, err)
}
return nil
}
// graftDatapath replaces obj in tail call map
func graftDatapath(ctx context.Context, mapPath, objPath, progSec string) error {
var err error
// FIXME: Replace cilium-map-migrate with Golang map migration
cmd := exec.CommandContext(ctx, "cilium-map-migrate", "-s", objPath)
cmd.Env = bpf.Environment()
if _, err = cmd.CombinedOutput(log, true); err != nil {
return err
}
defer func() {
var retCode string
if err == nil {
retCode = "0"
} else {
retCode = "1"
}
args := []string{"-e", objPath, "-r", retCode}
cmd := exec.CommandContext(ctx, "cilium-map-migrate", args...)
cmd.Env = bpf.Environment()
_, _ = cmd.CombinedOutput(log, true) // ignore errors
}()
// FIXME: replace exec with native call
// FIXME: only key 0 right now, could be made more flexible
args := []string{"exec", "bpf", "graft", mapPath, "key", "0",
"obj", objPath, "sec", progSec,
}
cmd = exec.CommandContext(ctx, "tc", args...).WithFilters(libbpfFixupMsg)
_, err = cmd.CombinedOutput(log, true)
if err != nil {
return fmt.Errorf("Failed to graft tc object: %s", err)
}
return nil
}
// RemoveTCFilters removes all tc filters from the given interface.
// Direction is passed as netlink.HANDLE_MIN_{INGRESS,EGRESS} via tcDir.
func RemoveTCFilters(ifName string, tcDir uint32) error {
link, err := netlink.LinkByName(ifName)
if err != nil {
return err
}
filters, err := netlink.FilterList(link, tcDir)
if err != nil {
return err
}
for _, f := range filters {
if err := netlink.FilterDel(f); err != nil {
return err
}
}
return nil
}
func setupDev(link netlink.Link) error {
ifName := link.Attrs().Name
if err := netlink.LinkSetUp(link); err != nil {
log.WithError(err).WithField("device", ifName).Warn("Could not set up the link")
return err
}
sysSettings := make([]sysctl.Setting, 0, 5)
if option.Config.EnableIPv6 {
sysSettings = append(sysSettings, sysctl.Setting{
Name: fmt.Sprintf("net.ipv6.conf.%s.forwarding", ifName), Val: "1", IgnoreErr: false})
}
if option.Config.EnableIPv4 {
sysSettings = append(sysSettings, []sysctl.Setting{
{Name: fmt.Sprintf("net.ipv4.conf.%s.forwarding", ifName), Val: "1", IgnoreErr: false},
{Name: fmt.Sprintf("net.ipv4.conf.%s.rp_filter", ifName), Val: "0", IgnoreErr: false},
{Name: fmt.Sprintf("net.ipv4.conf.%s.accept_local", ifName), Val: "1", IgnoreErr: false},
{Name: fmt.Sprintf("net.ipv4.conf.%s.send_redirects", ifName), Val: "0", IgnoreErr: false},
}...)
}
if err := sysctl.ApplySettings(sysSettings); err != nil {
return err
}
return nil
}
func setupVethPair(name, peerName string) error {
// Create the veth pair if it doesn't exist.
if _, err := netlink.LinkByName(name); err != nil {
hostMac, err := mac.GenerateRandMAC()
if err != nil {
return err
}
peerMac, err := mac.GenerateRandMAC()
if err != nil {
return err
}
veth := &netlink.Veth{
LinkAttrs: netlink.LinkAttrs{
Name: name,
HardwareAddr: net.HardwareAddr(hostMac),
},
PeerName: peerName,
PeerHardwareAddr: net.HardwareAddr(peerMac),
}
if err := netlink.LinkAdd(veth); err != nil {
return err
}
}
veth, err := netlink.LinkByName(name)
if err != nil {
return err
}
if err := setupDev(veth); err != nil {
return err
}
peer, err := netlink.LinkByName(peerName)
if err != nil {
return err
}
if err := setupDev(peer); err != nil {
return err
}
return nil
}
func setupIpvlan(name string, nativeLink netlink.Link) (*netlink.IPVlan, error) {
hostLink, err := netlink.LinkByName(name)
if err == nil {
// Ignore the error.
netlink.LinkDel(hostLink)
}
ipvlan := &netlink.IPVlan{
LinkAttrs: netlink.LinkAttrs{
Name: name,
ParentIndex: nativeLink.Attrs().Index,
},
Mode: netlink.IPVLAN_MODE_L3,
}
if err := netlink.LinkAdd(ipvlan); err != nil {
return nil, err
}
if err := setupDev(ipvlan); err != nil {
return nil, err
}
return ipvlan, nil
}
// setupBaseDevice decides which and what kind of interfaces should be set up as
// the first step of datapath initialization, then performs the setup (and
// creation, if needed) of those interfaces. It returns two links and an error.
// By default, it sets up the veth pair - cilium_host and cilium_net.
// In ipvlan mode, it creates the cilium_host ipvlan with the native device as a
// parent.
func setupBaseDevice(nativeDevs []netlink.Link, mode baseDeviceMode, mtu int) (netlink.Link, netlink.Link, error) {
switch mode {
case ipvlanMode:
ipvlan, err := setupIpvlan(defaults.HostDevice, nativeDevs[0])
if err != nil {
return nil, nil, err
}
if err := netlink.LinkSetMTU(ipvlan, mtu); err != nil {
return nil, nil, err
}
return ipvlan, ipvlan, nil
default:
if err := setupVethPair(defaults.HostDevice, defaults.SecondHostDevice); err != nil {
return nil, nil, err
}
linkHost, err := netlink.LinkByName(defaults.HostDevice)
if err != nil {
return nil, nil, err
}
linkNet, err := netlink.LinkByName(defaults.SecondHostDevice)
if err != nil {
return nil, nil, err
}
if err := netlink.LinkSetARPOff(linkHost); err != nil {
return nil, nil, err
}
if err := netlink.LinkSetARPOff(linkNet); err != nil {
return nil, nil, err
}
if err := netlink.LinkSetMTU(linkHost, mtu); err != nil {
return nil, nil, err
}
if err := netlink.LinkSetMTU(linkNet, mtu); err != nil {
return nil, nil, err
}
return linkHost, linkNet, nil
}
}