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// Copyright 2018 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 main
import (
"fmt"
"net"
"syscall"
"github.com/containernetworking/plugins/pkg/ip"
"github.com/vishvananda/netlink"
)
const latencyInMillis = 25
func CreateIfb(ifbDeviceName string, mtu int) error {
err := netlink.LinkAdd(&netlink.Ifb{
LinkAttrs: netlink.LinkAttrs{
Name: ifbDeviceName,
Flags: net.FlagUp,
MTU: mtu,
},
})
if err != nil {
return fmt.Errorf("adding link: %s", err)
}
return nil
}
func TeardownIfb(deviceName string) error {
_, err := ip.DelLinkByNameAddr(deviceName)
if err != nil && err == ip.ErrLinkNotFound {
return nil
}
return err
}
func CreateIngressQdisc(rateInBits, burstInBits uint64, hostDeviceName string) error {
hostDevice, err := netlink.LinkByName(hostDeviceName)
if err != nil {
return fmt.Errorf("get host device: %s", err)
}
return createTBF(rateInBits, burstInBits, hostDevice.Attrs().Index)
}
func CreateEgressQdisc(rateInBits, burstInBits uint64, hostDeviceName string, ifbDeviceName string) error {
ifbDevice, err := netlink.LinkByName(ifbDeviceName)
if err != nil {
return fmt.Errorf("get ifb device: %s", err)
}
hostDevice, err := netlink.LinkByName(hostDeviceName)
if err != nil {
return fmt.Errorf("get host device: %s", err)
}
// add qdisc ingress on host device
ingress := &netlink.Ingress{
QdiscAttrs: netlink.QdiscAttrs{
LinkIndex: hostDevice.Attrs().Index,
Handle: netlink.MakeHandle(0xffff, 0), // ffff:
Parent: netlink.HANDLE_INGRESS,
},
}
err = netlink.QdiscAdd(ingress)
if err != nil {
return fmt.Errorf("create ingress qdisc: %s", err)
}
// add filter on host device to mirror traffic to ifb device
filter := &netlink.U32{
FilterAttrs: netlink.FilterAttrs{
LinkIndex: hostDevice.Attrs().Index,
Parent: ingress.QdiscAttrs.Handle,
Priority: 1,
Protocol: syscall.ETH_P_ALL,
},
ClassId: netlink.MakeHandle(1, 1),
RedirIndex: ifbDevice.Attrs().Index,
Actions: []netlink.Action{
&netlink.MirredAction{
ActionAttrs: netlink.ActionAttrs{},
MirredAction: netlink.TCA_EGRESS_REDIR,
Ifindex: ifbDevice.Attrs().Index,
},
},
}
err = netlink.FilterAdd(filter)
if err != nil {
return fmt.Errorf("add filter: %s", err)
}
// throttle traffic on ifb device
err = createTBF(rateInBits, burstInBits, ifbDevice.Attrs().Index)
if err != nil {
return fmt.Errorf("create ifb qdisc: %s", err)
}
return nil
}
func createTBF(rateInBits, burstInBits uint64, linkIndex int) error {
// Equivalent to
// tc qdisc add dev link root tbf
// rate netConf.BandwidthLimits.Rate
// burst netConf.BandwidthLimits.Burst
if rateInBits <= 0 {
return fmt.Errorf("invalid rate: %d", rateInBits)
}
if burstInBits <= 0 {
return fmt.Errorf("invalid burst: %d", burstInBits)
}
rateInBytes := rateInBits / 8
burstInBytes := burstInBits / 8
bufferInBytes := buffer(uint64(rateInBytes), uint32(burstInBytes))
latency := latencyInUsec(latencyInMillis)
limitInBytes := limit(uint64(rateInBytes), latency, uint32(burstInBytes))
qdisc := &netlink.Tbf{
QdiscAttrs: netlink.QdiscAttrs{
LinkIndex: linkIndex,
Handle: netlink.MakeHandle(1, 0),
Parent: netlink.HANDLE_ROOT,
},
Limit: uint32(limitInBytes),
Rate: uint64(rateInBytes),
Buffer: uint32(bufferInBytes),
}
err := netlink.QdiscAdd(qdisc)
if err != nil {
return fmt.Errorf("create qdisc: %s", err)
}
return nil
}
func tick2Time(tick uint32) uint32 {
return uint32(float64(tick) / float64(netlink.TickInUsec()))
}
func time2Tick(time uint32) uint32 {
return uint32(float64(time) * float64(netlink.TickInUsec()))
}
func buffer(rate uint64, burst uint32) uint32 {
return time2Tick(uint32(float64(burst) * float64(netlink.TIME_UNITS_PER_SEC) / float64(rate)))
}
func limit(rate uint64, latency float64, buffer uint32) uint32 {
return uint32(float64(rate)*latency/float64(netlink.TIME_UNITS_PER_SEC)) + buffer
}
func latencyInUsec(latencyInMillis float64) float64 {
return float64(netlink.TIME_UNITS_PER_SEC) * (latencyInMillis / 1000.0)
}
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