netlink/qdisc_linux.go

713 lines
19 KiB
Go

package netlink
import (
"fmt"
"io/ioutil"
"strconv"
"strings"
"syscall"
"github.com/vishvananda/netlink/nl"
"golang.org/x/sys/unix"
)
// NOTE function is here because it uses other linux functions
func NewNetem(attrs QdiscAttrs, nattrs NetemQdiscAttrs) *Netem {
var limit uint32 = 1000
var lossCorr, delayCorr, duplicateCorr uint32
var reorderProb, reorderCorr uint32
var corruptProb, corruptCorr uint32
latency := nattrs.Latency
loss := Percentage2u32(nattrs.Loss)
gap := nattrs.Gap
duplicate := Percentage2u32(nattrs.Duplicate)
jitter := nattrs.Jitter
// Correlation
if latency > 0 && jitter > 0 {
delayCorr = Percentage2u32(nattrs.DelayCorr)
}
if loss > 0 {
lossCorr = Percentage2u32(nattrs.LossCorr)
}
if duplicate > 0 {
duplicateCorr = Percentage2u32(nattrs.DuplicateCorr)
}
// FIXME should validate values(like loss/duplicate are percentages...)
latency = time2Tick(latency)
if nattrs.Limit != 0 {
limit = nattrs.Limit
}
// Jitter is only value if latency is > 0
if latency > 0 {
jitter = time2Tick(jitter)
}
reorderProb = Percentage2u32(nattrs.ReorderProb)
reorderCorr = Percentage2u32(nattrs.ReorderCorr)
if reorderProb > 0 {
// ERROR if lantency == 0
if gap == 0 {
gap = 1
}
}
corruptProb = Percentage2u32(nattrs.CorruptProb)
corruptCorr = Percentage2u32(nattrs.CorruptCorr)
return &Netem{
QdiscAttrs: attrs,
Latency: latency,
DelayCorr: delayCorr,
Limit: limit,
Loss: loss,
LossCorr: lossCorr,
Gap: gap,
Duplicate: duplicate,
DuplicateCorr: duplicateCorr,
Jitter: jitter,
ReorderProb: reorderProb,
ReorderCorr: reorderCorr,
CorruptProb: corruptProb,
CorruptCorr: corruptCorr,
}
}
// QdiscDel will delete a qdisc from the system.
// Equivalent to: `tc qdisc del $qdisc`
func QdiscDel(qdisc Qdisc) error {
return pkgHandle.QdiscDel(qdisc)
}
// QdiscDel will delete a qdisc from the system.
// Equivalent to: `tc qdisc del $qdisc`
func (h *Handle) QdiscDel(qdisc Qdisc) error {
return h.qdiscModify(unix.RTM_DELQDISC, 0, qdisc)
}
// QdiscChange will change a qdisc in place
// Equivalent to: `tc qdisc change $qdisc`
// The parent and handle MUST NOT be changed.
func QdiscChange(qdisc Qdisc) error {
return pkgHandle.QdiscChange(qdisc)
}
// QdiscChange will change a qdisc in place
// Equivalent to: `tc qdisc change $qdisc`
// The parent and handle MUST NOT be changed.
func (h *Handle) QdiscChange(qdisc Qdisc) error {
return h.qdiscModify(unix.RTM_NEWQDISC, 0, qdisc)
}
// QdiscReplace will replace a qdisc to the system.
// Equivalent to: `tc qdisc replace $qdisc`
// The handle MUST change.
func QdiscReplace(qdisc Qdisc) error {
return pkgHandle.QdiscReplace(qdisc)
}
// QdiscReplace will replace a qdisc to the system.
// Equivalent to: `tc qdisc replace $qdisc`
// The handle MUST change.
func (h *Handle) QdiscReplace(qdisc Qdisc) error {
return h.qdiscModify(
unix.RTM_NEWQDISC,
unix.NLM_F_CREATE|unix.NLM_F_REPLACE,
qdisc)
}
// QdiscAdd will add a qdisc to the system.
// Equivalent to: `tc qdisc add $qdisc`
func QdiscAdd(qdisc Qdisc) error {
return pkgHandle.QdiscAdd(qdisc)
}
// QdiscAdd will add a qdisc to the system.
// Equivalent to: `tc qdisc add $qdisc`
func (h *Handle) QdiscAdd(qdisc Qdisc) error {
return h.qdiscModify(
unix.RTM_NEWQDISC,
unix.NLM_F_CREATE|unix.NLM_F_EXCL,
qdisc)
}
func (h *Handle) qdiscModify(cmd, flags int, qdisc Qdisc) error {
req := h.newNetlinkRequest(cmd, flags|unix.NLM_F_ACK)
base := qdisc.Attrs()
msg := &nl.TcMsg{
Family: nl.FAMILY_ALL,
Ifindex: int32(base.LinkIndex),
Handle: base.Handle,
Parent: base.Parent,
}
req.AddData(msg)
// When deleting don't bother building the rest of the netlink payload
if cmd != unix.RTM_DELQDISC {
if err := qdiscPayload(req, qdisc); err != nil {
return err
}
}
_, err := req.Execute(unix.NETLINK_ROUTE, 0)
return err
}
func qdiscPayload(req *nl.NetlinkRequest, qdisc Qdisc) error {
req.AddData(nl.NewRtAttr(nl.TCA_KIND, nl.ZeroTerminated(qdisc.Type())))
options := nl.NewRtAttr(nl.TCA_OPTIONS, nil)
switch qdisc := qdisc.(type) {
case *Prio:
tcmap := nl.TcPrioMap{
Bands: int32(qdisc.Bands),
Priomap: qdisc.PriorityMap,
}
options = nl.NewRtAttr(nl.TCA_OPTIONS, tcmap.Serialize())
case *Tbf:
opt := nl.TcTbfQopt{}
opt.Rate.Rate = uint32(qdisc.Rate)
opt.Peakrate.Rate = uint32(qdisc.Peakrate)
opt.Limit = qdisc.Limit
opt.Buffer = qdisc.Buffer
options.AddRtAttr(nl.TCA_TBF_PARMS, opt.Serialize())
if qdisc.Rate >= uint64(1<<32) {
options.AddRtAttr(nl.TCA_TBF_RATE64, nl.Uint64Attr(qdisc.Rate))
}
if qdisc.Peakrate >= uint64(1<<32) {
options.AddRtAttr(nl.TCA_TBF_PRATE64, nl.Uint64Attr(qdisc.Peakrate))
}
if qdisc.Peakrate > 0 {
options.AddRtAttr(nl.TCA_TBF_PBURST, nl.Uint32Attr(qdisc.Minburst))
}
case *Htb:
opt := nl.TcHtbGlob{}
opt.Version = qdisc.Version
opt.Rate2Quantum = qdisc.Rate2Quantum
opt.Defcls = qdisc.Defcls
// TODO: Handle Debug properly. For now default to 0
opt.Debug = qdisc.Debug
opt.DirectPkts = qdisc.DirectPkts
options.AddRtAttr(nl.TCA_HTB_INIT, opt.Serialize())
// options.AddRtAttr(nl.TCA_HTB_DIRECT_QLEN, opt.Serialize())
case *Hfsc:
opt := nl.TcHfscOpt{}
opt.Defcls = qdisc.Defcls
options = nl.NewRtAttr(nl.TCA_OPTIONS, opt.Serialize())
case *Netem:
opt := nl.TcNetemQopt{}
opt.Latency = qdisc.Latency
opt.Limit = qdisc.Limit
opt.Loss = qdisc.Loss
opt.Gap = qdisc.Gap
opt.Duplicate = qdisc.Duplicate
opt.Jitter = qdisc.Jitter
options = nl.NewRtAttr(nl.TCA_OPTIONS, opt.Serialize())
// Correlation
corr := nl.TcNetemCorr{}
corr.DelayCorr = qdisc.DelayCorr
corr.LossCorr = qdisc.LossCorr
corr.DupCorr = qdisc.DuplicateCorr
if corr.DelayCorr > 0 || corr.LossCorr > 0 || corr.DupCorr > 0 {
options.AddRtAttr(nl.TCA_NETEM_CORR, corr.Serialize())
}
// Corruption
corruption := nl.TcNetemCorrupt{}
corruption.Probability = qdisc.CorruptProb
corruption.Correlation = qdisc.CorruptCorr
if corruption.Probability > 0 {
options.AddRtAttr(nl.TCA_NETEM_CORRUPT, corruption.Serialize())
}
// Reorder
reorder := nl.TcNetemReorder{}
reorder.Probability = qdisc.ReorderProb
reorder.Correlation = qdisc.ReorderCorr
if reorder.Probability > 0 {
options.AddRtAttr(nl.TCA_NETEM_REORDER, reorder.Serialize())
}
case *Ingress:
// ingress filters must use the proper handle
if qdisc.Attrs().Parent != HANDLE_INGRESS {
return fmt.Errorf("Ingress filters must set Parent to HANDLE_INGRESS")
}
case *FqCodel:
options.AddRtAttr(nl.TCA_FQ_CODEL_ECN, nl.Uint32Attr((uint32(qdisc.ECN))))
if qdisc.Limit > 0 {
options.AddRtAttr(nl.TCA_FQ_CODEL_LIMIT, nl.Uint32Attr((uint32(qdisc.Limit))))
}
if qdisc.Interval > 0 {
options.AddRtAttr(nl.TCA_FQ_CODEL_INTERVAL, nl.Uint32Attr((uint32(qdisc.Interval))))
}
if qdisc.Flows > 0 {
options.AddRtAttr(nl.TCA_FQ_CODEL_FLOWS, nl.Uint32Attr((uint32(qdisc.Flows))))
}
if qdisc.Quantum > 0 {
options.AddRtAttr(nl.TCA_FQ_CODEL_QUANTUM, nl.Uint32Attr((uint32(qdisc.Quantum))))
}
if qdisc.CEThreshold > 0 {
options.AddRtAttr(nl.TCA_FQ_CODEL_CE_THRESHOLD, nl.Uint32Attr(qdisc.CEThreshold))
}
if qdisc.DropBatchSize > 0 {
options.AddRtAttr(nl.TCA_FQ_CODEL_DROP_BATCH_SIZE, nl.Uint32Attr(qdisc.DropBatchSize))
}
if qdisc.MemoryLimit > 0 {
options.AddRtAttr(nl.TCA_FQ_CODEL_MEMORY_LIMIT, nl.Uint32Attr(qdisc.MemoryLimit))
}
case *Fq:
options.AddRtAttr(nl.TCA_FQ_RATE_ENABLE, nl.Uint32Attr((uint32(qdisc.Pacing))))
if qdisc.Buckets > 0 {
options.AddRtAttr(nl.TCA_FQ_BUCKETS_LOG, nl.Uint32Attr((uint32(qdisc.Buckets))))
}
if qdisc.LowRateThreshold > 0 {
options.AddRtAttr(nl.TCA_FQ_LOW_RATE_THRESHOLD, nl.Uint32Attr((uint32(qdisc.LowRateThreshold))))
}
if qdisc.Quantum > 0 {
options.AddRtAttr(nl.TCA_FQ_QUANTUM, nl.Uint32Attr((uint32(qdisc.Quantum))))
}
if qdisc.InitialQuantum > 0 {
options.AddRtAttr(nl.TCA_FQ_INITIAL_QUANTUM, nl.Uint32Attr((uint32(qdisc.InitialQuantum))))
}
if qdisc.FlowRefillDelay > 0 {
options.AddRtAttr(nl.TCA_FQ_FLOW_REFILL_DELAY, nl.Uint32Attr((uint32(qdisc.FlowRefillDelay))))
}
if qdisc.FlowPacketLimit > 0 {
options.AddRtAttr(nl.TCA_FQ_FLOW_PLIMIT, nl.Uint32Attr((uint32(qdisc.FlowPacketLimit))))
}
if qdisc.FlowMaxRate > 0 {
options.AddRtAttr(nl.TCA_FQ_FLOW_MAX_RATE, nl.Uint32Attr((uint32(qdisc.FlowMaxRate))))
}
if qdisc.FlowDefaultRate > 0 {
options.AddRtAttr(nl.TCA_FQ_FLOW_DEFAULT_RATE, nl.Uint32Attr((uint32(qdisc.FlowDefaultRate))))
}
case *Sfq:
opt := nl.TcSfqQoptV1{}
opt.TcSfqQopt.Quantum = qdisc.Quantum
opt.TcSfqQopt.Perturb = int32(qdisc.Perturb)
opt.TcSfqQopt.Limit = qdisc.Limit
opt.TcSfqQopt.Divisor = qdisc.Divisor
options = nl.NewRtAttr(nl.TCA_OPTIONS, opt.Serialize())
default:
options = nil
}
if options != nil {
req.AddData(options)
}
return nil
}
// QdiscList gets a list of qdiscs in the system.
// Equivalent to: `tc qdisc show`.
// The list can be filtered by link.
func QdiscList(link Link) ([]Qdisc, error) {
return pkgHandle.QdiscList(link)
}
// QdiscList gets a list of qdiscs in the system.
// Equivalent to: `tc qdisc show`.
// The list can be filtered by link.
func (h *Handle) QdiscList(link Link) ([]Qdisc, error) {
req := h.newNetlinkRequest(unix.RTM_GETQDISC, unix.NLM_F_DUMP)
index := int32(0)
if link != nil {
base := link.Attrs()
h.ensureIndex(base)
index = int32(base.Index)
}
msg := &nl.TcMsg{
Family: nl.FAMILY_ALL,
Ifindex: index,
}
req.AddData(msg)
msgs, err := req.Execute(unix.NETLINK_ROUTE, unix.RTM_NEWQDISC)
if err != nil {
return nil, err
}
var res []Qdisc
for _, m := range msgs {
msg := nl.DeserializeTcMsg(m)
attrs, err := nl.ParseRouteAttr(m[msg.Len():])
if err != nil {
return nil, err
}
// skip qdiscs from other interfaces
if link != nil && msg.Ifindex != index {
continue
}
base := QdiscAttrs{
LinkIndex: int(msg.Ifindex),
Handle: msg.Handle,
Parent: msg.Parent,
Refcnt: msg.Info,
}
var qdisc Qdisc
qdiscType := ""
for _, attr := range attrs {
switch attr.Attr.Type {
case nl.TCA_KIND:
qdiscType = string(attr.Value[:len(attr.Value)-1])
switch qdiscType {
case "pfifo_fast":
qdisc = &PfifoFast{}
case "prio":
qdisc = &Prio{}
case "tbf":
qdisc = &Tbf{}
case "ingress":
qdisc = &Ingress{}
case "htb":
qdisc = &Htb{}
case "fq":
qdisc = &Fq{}
case "hfsc":
qdisc = &Hfsc{}
case "fq_codel":
qdisc = &FqCodel{}
case "netem":
qdisc = &Netem{}
case "sfq":
qdisc = &Sfq{}
default:
qdisc = &GenericQdisc{QdiscType: qdiscType}
}
case nl.TCA_OPTIONS:
switch qdiscType {
case "pfifo_fast":
// pfifo returns TcPrioMap directly without wrapping it in rtattr
if err := parsePfifoFastData(qdisc, attr.Value); err != nil {
return nil, err
}
case "prio":
// prio returns TcPrioMap directly without wrapping it in rtattr
if err := parsePrioData(qdisc, attr.Value); err != nil {
return nil, err
}
case "tbf":
data, err := nl.ParseRouteAttr(attr.Value)
if err != nil {
return nil, err
}
if err := parseTbfData(qdisc, data); err != nil {
return nil, err
}
case "hfsc":
if err := parseHfscData(qdisc, attr.Value); err != nil {
return nil, err
}
case "htb":
data, err := nl.ParseRouteAttr(attr.Value)
if err != nil {
return nil, err
}
if err := parseHtbData(qdisc, data); err != nil {
return nil, err
}
case "fq":
data, err := nl.ParseRouteAttr(attr.Value)
if err != nil {
return nil, err
}
if err := parseFqData(qdisc, data); err != nil {
return nil, err
}
case "fq_codel":
data, err := nl.ParseRouteAttr(attr.Value)
if err != nil {
return nil, err
}
if err := parseFqCodelData(qdisc, data); err != nil {
return nil, err
}
case "netem":
if err := parseNetemData(qdisc, attr.Value); err != nil {
return nil, err
}
case "sfq":
if err := parseSfqData(qdisc, attr.Value); err != nil {
return nil, err
}
// no options for ingress
}
}
}
*qdisc.Attrs() = base
res = append(res, qdisc)
}
return res, nil
}
func parsePfifoFastData(qdisc Qdisc, value []byte) error {
pfifo := qdisc.(*PfifoFast)
tcmap := nl.DeserializeTcPrioMap(value)
pfifo.PriorityMap = tcmap.Priomap
pfifo.Bands = uint8(tcmap.Bands)
return nil
}
func parsePrioData(qdisc Qdisc, value []byte) error {
prio := qdisc.(*Prio)
tcmap := nl.DeserializeTcPrioMap(value)
prio.PriorityMap = tcmap.Priomap
prio.Bands = uint8(tcmap.Bands)
return nil
}
func parseHtbData(qdisc Qdisc, data []syscall.NetlinkRouteAttr) error {
htb := qdisc.(*Htb)
for _, datum := range data {
switch datum.Attr.Type {
case nl.TCA_HTB_INIT:
opt := nl.DeserializeTcHtbGlob(datum.Value)
htb.Version = opt.Version
htb.Rate2Quantum = opt.Rate2Quantum
htb.Defcls = opt.Defcls
htb.Debug = opt.Debug
htb.DirectPkts = opt.DirectPkts
case nl.TCA_HTB_DIRECT_QLEN:
// TODO
//htb.DirectQlen = native.uint32(datum.Value)
}
}
return nil
}
func parseFqCodelData(qdisc Qdisc, data []syscall.NetlinkRouteAttr) error {
fqCodel := qdisc.(*FqCodel)
for _, datum := range data {
switch datum.Attr.Type {
case nl.TCA_FQ_CODEL_TARGET:
fqCodel.Target = native.Uint32(datum.Value)
case nl.TCA_FQ_CODEL_LIMIT:
fqCodel.Limit = native.Uint32(datum.Value)
case nl.TCA_FQ_CODEL_INTERVAL:
fqCodel.Interval = native.Uint32(datum.Value)
case nl.TCA_FQ_CODEL_ECN:
fqCodel.ECN = native.Uint32(datum.Value)
case nl.TCA_FQ_CODEL_FLOWS:
fqCodel.Flows = native.Uint32(datum.Value)
case nl.TCA_FQ_CODEL_QUANTUM:
fqCodel.Quantum = native.Uint32(datum.Value)
case nl.TCA_FQ_CODEL_CE_THRESHOLD:
fqCodel.CEThreshold = native.Uint32(datum.Value)
case nl.TCA_FQ_CODEL_DROP_BATCH_SIZE:
fqCodel.DropBatchSize = native.Uint32(datum.Value)
case nl.TCA_FQ_CODEL_MEMORY_LIMIT:
fqCodel.MemoryLimit = native.Uint32(datum.Value)
}
}
return nil
}
func parseHfscData(qdisc Qdisc, data []byte) error {
Hfsc := qdisc.(*Hfsc)
Hfsc.Defcls = native.Uint16(data)
return nil
}
func parseFqData(qdisc Qdisc, data []syscall.NetlinkRouteAttr) error {
fq := qdisc.(*Fq)
for _, datum := range data {
switch datum.Attr.Type {
case nl.TCA_FQ_BUCKETS_LOG:
fq.Buckets = native.Uint32(datum.Value)
case nl.TCA_FQ_LOW_RATE_THRESHOLD:
fq.LowRateThreshold = native.Uint32(datum.Value)
case nl.TCA_FQ_QUANTUM:
fq.Quantum = native.Uint32(datum.Value)
case nl.TCA_FQ_RATE_ENABLE:
fq.Pacing = native.Uint32(datum.Value)
case nl.TCA_FQ_INITIAL_QUANTUM:
fq.InitialQuantum = native.Uint32(datum.Value)
case nl.TCA_FQ_ORPHAN_MASK:
// TODO
case nl.TCA_FQ_FLOW_REFILL_DELAY:
fq.FlowRefillDelay = native.Uint32(datum.Value)
case nl.TCA_FQ_FLOW_PLIMIT:
fq.FlowPacketLimit = native.Uint32(datum.Value)
case nl.TCA_FQ_PLIMIT:
fq.PacketLimit = native.Uint32(datum.Value)
case nl.TCA_FQ_FLOW_MAX_RATE:
fq.FlowMaxRate = native.Uint32(datum.Value)
case nl.TCA_FQ_FLOW_DEFAULT_RATE:
fq.FlowDefaultRate = native.Uint32(datum.Value)
}
}
return nil
}
func parseNetemData(qdisc Qdisc, value []byte) error {
netem := qdisc.(*Netem)
opt := nl.DeserializeTcNetemQopt(value)
netem.Latency = opt.Latency
netem.Limit = opt.Limit
netem.Loss = opt.Loss
netem.Gap = opt.Gap
netem.Duplicate = opt.Duplicate
netem.Jitter = opt.Jitter
data, err := nl.ParseRouteAttr(value[nl.SizeofTcNetemQopt:])
if err != nil {
return err
}
for _, datum := range data {
switch datum.Attr.Type {
case nl.TCA_NETEM_CORR:
opt := nl.DeserializeTcNetemCorr(datum.Value)
netem.DelayCorr = opt.DelayCorr
netem.LossCorr = opt.LossCorr
netem.DuplicateCorr = opt.DupCorr
case nl.TCA_NETEM_CORRUPT:
opt := nl.DeserializeTcNetemCorrupt(datum.Value)
netem.CorruptProb = opt.Probability
netem.CorruptCorr = opt.Correlation
case nl.TCA_NETEM_REORDER:
opt := nl.DeserializeTcNetemReorder(datum.Value)
netem.ReorderProb = opt.Probability
netem.ReorderCorr = opt.Correlation
}
}
return nil
}
func parseTbfData(qdisc Qdisc, data []syscall.NetlinkRouteAttr) error {
tbf := qdisc.(*Tbf)
for _, datum := range data {
switch datum.Attr.Type {
case nl.TCA_TBF_PARMS:
opt := nl.DeserializeTcTbfQopt(datum.Value)
tbf.Rate = uint64(opt.Rate.Rate)
tbf.Peakrate = uint64(opt.Peakrate.Rate)
tbf.Limit = opt.Limit
tbf.Buffer = opt.Buffer
case nl.TCA_TBF_RATE64:
tbf.Rate = native.Uint64(datum.Value[0:8])
case nl.TCA_TBF_PRATE64:
tbf.Peakrate = native.Uint64(datum.Value[0:8])
case nl.TCA_TBF_PBURST:
tbf.Minburst = native.Uint32(datum.Value[0:4])
}
}
return nil
}
func parseSfqData(qdisc Qdisc, value []byte) error {
sfq := qdisc.(*Sfq)
opt := nl.DeserializeTcSfqQoptV1(value)
sfq.Quantum = opt.TcSfqQopt.Quantum
sfq.Perturb = uint8(opt.TcSfqQopt.Perturb)
sfq.Limit = opt.TcSfqQopt.Limit
sfq.Divisor = opt.TcSfqQopt.Divisor
return nil
}
const (
TIME_UNITS_PER_SEC = 1000000
)
var (
tickInUsec float64
clockFactor float64
hz float64
)
func initClock() {
data, err := ioutil.ReadFile("/proc/net/psched")
if err != nil {
return
}
parts := strings.Split(strings.TrimSpace(string(data)), " ")
if len(parts) < 4 {
return
}
var vals [4]uint64
for i := range vals {
val, err := strconv.ParseUint(parts[i], 16, 32)
if err != nil {
return
}
vals[i] = val
}
// compatibility
if vals[2] == 1000000000 {
vals[0] = vals[1]
}
clockFactor = float64(vals[2]) / TIME_UNITS_PER_SEC
tickInUsec = float64(vals[0]) / float64(vals[1]) * clockFactor
if vals[2] == 1000000 {
// ref https://git.kernel.org/pub/scm/network/iproute2/iproute2.git/tree/lib/utils.c#n963
hz = float64(vals[3])
} else {
hz = 100
}
}
func TickInUsec() float64 {
if tickInUsec == 0.0 {
initClock()
}
return tickInUsec
}
func ClockFactor() float64 {
if clockFactor == 0.0 {
initClock()
}
return clockFactor
}
func Hz() float64 {
if hz == 0.0 {
initClock()
}
return hz
}
func time2Tick(time uint32) uint32 {
return uint32(float64(time) * TickInUsec())
}
func tick2Time(tick uint32) uint32 {
return uint32(float64(tick) / TickInUsec())
}
func time2Ktime(time uint32) uint32 {
return uint32(float64(time) * ClockFactor())
}
func ktime2Time(ktime uint32) uint32 {
return uint32(float64(ktime) / ClockFactor())
}
func burst(rate uint64, buffer uint32) uint32 {
return uint32(float64(rate) * float64(tick2Time(buffer)) / TIME_UNITS_PER_SEC)
}
func latency(rate uint64, limit, buffer uint32) float64 {
return TIME_UNITS_PER_SEC*(float64(limit)/float64(rate)) - float64(tick2Time(buffer))
}
func Xmittime(rate uint64, size uint32) uint32 {
// https://git.kernel.org/pub/scm/network/iproute2/iproute2.git/tree/tc/tc_core.c#n62
return time2Tick(uint32(TIME_UNITS_PER_SEC * (float64(size) / float64(rate))))
}
func Xmitsize(rate uint64, ticks uint32) uint32 {
return uint32((float64(rate) * float64(tick2Time(ticks))) / TIME_UNITS_PER_SEC)
}