netlink/filter_linux.go

561 lines
15 KiB
Go

package netlink
import (
"bytes"
"encoding/binary"
"errors"
"fmt"
"syscall"
"github.com/vishvananda/netlink/nl"
)
// Fw filter filters on firewall marks
// NOTE: this is in filter_linux because it refers to nl.TcPolice which
// is defined in nl/tc_linux.go
type Fw struct {
FilterAttrs
ClassId uint32
// TODO remove nl type from interface
Police nl.TcPolice
InDev string
// TODO Action
Mask uint32
AvRate uint32
Rtab [256]uint32
Ptab [256]uint32
}
func NewFw(attrs FilterAttrs, fattrs FilterFwAttrs) (*Fw, error) {
var rtab [256]uint32
var ptab [256]uint32
rcellLog := -1
pcellLog := -1
avrate := fattrs.AvRate / 8
police := nl.TcPolice{}
police.Rate.Rate = fattrs.Rate / 8
police.PeakRate.Rate = fattrs.PeakRate / 8
buffer := fattrs.Buffer
linklayer := nl.LINKLAYER_ETHERNET
if fattrs.LinkLayer != nl.LINKLAYER_UNSPEC {
linklayer = fattrs.LinkLayer
}
police.Action = int32(fattrs.Action)
if police.Rate.Rate != 0 {
police.Rate.Mpu = fattrs.Mpu
police.Rate.Overhead = fattrs.Overhead
if CalcRtable(&police.Rate, rtab, rcellLog, fattrs.Mtu, linklayer) < 0 {
return nil, errors.New("TBF: failed to calculate rate table")
}
police.Burst = uint32(Xmittime(uint64(police.Rate.Rate), uint32(buffer)))
}
police.Mtu = fattrs.Mtu
if police.PeakRate.Rate != 0 {
police.PeakRate.Mpu = fattrs.Mpu
police.PeakRate.Overhead = fattrs.Overhead
if CalcRtable(&police.PeakRate, ptab, pcellLog, fattrs.Mtu, linklayer) < 0 {
return nil, errors.New("POLICE: failed to calculate peak rate table")
}
}
return &Fw{
FilterAttrs: attrs,
ClassId: fattrs.ClassId,
InDev: fattrs.InDev,
Mask: fattrs.Mask,
Police: police,
AvRate: avrate,
Rtab: rtab,
Ptab: ptab,
}, nil
}
func (filter *Fw) Attrs() *FilterAttrs {
return &filter.FilterAttrs
}
func (filter *Fw) Type() string {
return "fw"
}
// FilterDel will delete a filter from the system.
// Equivalent to: `tc filter del $filter`
func FilterDel(filter Filter) error {
return pkgHandle.FilterDel(filter)
}
// FilterDel will delete a filter from the system.
// Equivalent to: `tc filter del $filter`
func (h *Handle) FilterDel(filter Filter) error {
req := h.newNetlinkRequest(syscall.RTM_DELTFILTER, syscall.NLM_F_ACK)
base := filter.Attrs()
msg := &nl.TcMsg{
Family: nl.FAMILY_ALL,
Ifindex: int32(base.LinkIndex),
Handle: base.Handle,
Parent: base.Parent,
Info: MakeHandle(base.Priority, nl.Swap16(base.Protocol)),
}
req.AddData(msg)
_, err := req.Execute(syscall.NETLINK_ROUTE, 0)
return err
}
// FilterAdd will add a filter to the system.
// Equivalent to: `tc filter add $filter`
func FilterAdd(filter Filter) error {
return pkgHandle.FilterAdd(filter)
}
// FilterAdd will add a filter to the system.
// Equivalent to: `tc filter add $filter`
func (h *Handle) FilterAdd(filter Filter) error {
native = nl.NativeEndian()
req := h.newNetlinkRequest(syscall.RTM_NEWTFILTER, syscall.NLM_F_CREATE|syscall.NLM_F_EXCL|syscall.NLM_F_ACK)
base := filter.Attrs()
msg := &nl.TcMsg{
Family: nl.FAMILY_ALL,
Ifindex: int32(base.LinkIndex),
Handle: base.Handle,
Parent: base.Parent,
Info: MakeHandle(base.Priority, nl.Swap16(base.Protocol)),
}
req.AddData(msg)
req.AddData(nl.NewRtAttr(nl.TCA_KIND, nl.ZeroTerminated(filter.Type())))
options := nl.NewRtAttr(nl.TCA_OPTIONS, nil)
if u32, ok := filter.(*U32); ok {
// match all
sel := nl.TcU32Sel{
Nkeys: 1,
Flags: nl.TC_U32_TERMINAL,
}
sel.Keys = append(sel.Keys, nl.TcU32Key{})
nl.NewRtAttrChild(options, nl.TCA_U32_SEL, sel.Serialize())
if u32.ClassId != 0 {
nl.NewRtAttrChild(options, nl.TCA_U32_CLASSID, nl.Uint32Attr(u32.ClassId))
}
actionsAttr := nl.NewRtAttrChild(options, nl.TCA_U32_ACT, nil)
// backwards compatibility
if u32.RedirIndex != 0 {
u32.Actions = append([]Action{NewMirredAction(u32.RedirIndex)}, u32.Actions...)
}
if err := EncodeActions(actionsAttr, u32.Actions); err != nil {
return err
}
} else if fw, ok := filter.(*Fw); ok {
if fw.Mask != 0 {
b := make([]byte, 4)
native.PutUint32(b, fw.Mask)
nl.NewRtAttrChild(options, nl.TCA_FW_MASK, b)
}
if fw.InDev != "" {
nl.NewRtAttrChild(options, nl.TCA_FW_INDEV, nl.ZeroTerminated(fw.InDev))
}
if (fw.Police != nl.TcPolice{}) {
police := nl.NewRtAttrChild(options, nl.TCA_FW_POLICE, nil)
nl.NewRtAttrChild(police, nl.TCA_POLICE_TBF, fw.Police.Serialize())
if (fw.Police.Rate != nl.TcRateSpec{}) {
payload := SerializeRtab(fw.Rtab)
nl.NewRtAttrChild(police, nl.TCA_POLICE_RATE, payload)
}
if (fw.Police.PeakRate != nl.TcRateSpec{}) {
payload := SerializeRtab(fw.Ptab)
nl.NewRtAttrChild(police, nl.TCA_POLICE_PEAKRATE, payload)
}
}
if fw.ClassId != 0 {
b := make([]byte, 4)
native.PutUint32(b, fw.ClassId)
nl.NewRtAttrChild(options, nl.TCA_FW_CLASSID, b)
}
} else if bpf, ok := filter.(*BpfFilter); ok {
var bpfFlags uint32
if bpf.ClassId != 0 {
nl.NewRtAttrChild(options, nl.TCA_BPF_CLASSID, nl.Uint32Attr(bpf.ClassId))
}
if bpf.Fd >= 0 {
nl.NewRtAttrChild(options, nl.TCA_BPF_FD, nl.Uint32Attr((uint32(bpf.Fd))))
}
if bpf.Name != "" {
nl.NewRtAttrChild(options, nl.TCA_BPF_NAME, nl.ZeroTerminated(bpf.Name))
}
if bpf.DirectAction {
bpfFlags |= nl.TCA_BPF_FLAG_ACT_DIRECT
}
nl.NewRtAttrChild(options, nl.TCA_BPF_FLAGS, nl.Uint32Attr(bpfFlags))
}
req.AddData(options)
_, err := req.Execute(syscall.NETLINK_ROUTE, 0)
return err
}
// FilterList gets a list of filters in the system.
// Equivalent to: `tc filter show`.
// Generally returns nothing if link and parent are not specified.
func FilterList(link Link, parent uint32) ([]Filter, error) {
return pkgHandle.FilterList(link, parent)
}
// FilterList gets a list of filters in the system.
// Equivalent to: `tc filter show`.
// Generally returns nothing if link and parent are not specified.
func (h *Handle) FilterList(link Link, parent uint32) ([]Filter, error) {
req := h.newNetlinkRequest(syscall.RTM_GETTFILTER, syscall.NLM_F_DUMP)
msg := &nl.TcMsg{
Family: nl.FAMILY_ALL,
Parent: parent,
}
if link != nil {
base := link.Attrs()
h.ensureIndex(base)
msg.Ifindex = int32(base.Index)
}
req.AddData(msg)
msgs, err := req.Execute(syscall.NETLINK_ROUTE, syscall.RTM_NEWTFILTER)
if err != nil {
return nil, err
}
var res []Filter
for _, m := range msgs {
msg := nl.DeserializeTcMsg(m)
attrs, err := nl.ParseRouteAttr(m[msg.Len():])
if err != nil {
return nil, err
}
base := FilterAttrs{
LinkIndex: int(msg.Ifindex),
Handle: msg.Handle,
Parent: msg.Parent,
}
base.Priority, base.Protocol = MajorMinor(msg.Info)
base.Protocol = nl.Swap16(base.Protocol)
var filter Filter
filterType := ""
detailed := false
for _, attr := range attrs {
switch attr.Attr.Type {
case nl.TCA_KIND:
filterType = string(attr.Value[:len(attr.Value)-1])
switch filterType {
case "u32":
filter = &U32{}
case "fw":
filter = &Fw{}
case "bpf":
filter = &BpfFilter{}
default:
filter = &GenericFilter{FilterType: filterType}
}
case nl.TCA_OPTIONS:
data, err := nl.ParseRouteAttr(attr.Value)
if err != nil {
return nil, err
}
switch filterType {
case "u32":
detailed, err = parseU32Data(filter, data)
if err != nil {
return nil, err
}
case "fw":
detailed, err = parseFwData(filter, data)
if err != nil {
return nil, err
}
case "bpf":
detailed, err = parseBpfData(filter, data)
if err != nil {
return nil, err
}
default:
detailed = true
}
}
}
// only return the detailed version of the filter
if detailed {
*filter.Attrs() = base
res = append(res, filter)
}
}
return res, nil
}
func toTcGen(attrs *ActionAttrs, tcgen *nl.TcGen) {
tcgen.Index = uint32(attrs.Index)
tcgen.Capab = uint32(attrs.Capab)
tcgen.Action = int32(attrs.Action)
tcgen.Refcnt = int32(attrs.Refcnt)
tcgen.Bindcnt = int32(attrs.Bindcnt)
}
func toAttrs(tcgen *nl.TcGen, attrs *ActionAttrs) {
attrs.Index = int(tcgen.Index)
attrs.Capab = int(tcgen.Capab)
attrs.Action = TcAct(tcgen.Action)
attrs.Refcnt = int(tcgen.Refcnt)
attrs.Bindcnt = int(tcgen.Bindcnt)
}
func EncodeActions(attr *nl.RtAttr, actions []Action) error {
tabIndex := int(nl.TCA_ACT_TAB)
for _, action := range actions {
switch action := action.(type) {
default:
return fmt.Errorf("unknown action type %s", action.Type())
case *MirredAction:
table := nl.NewRtAttrChild(attr, tabIndex, nil)
tabIndex++
nl.NewRtAttrChild(table, nl.TCA_ACT_KIND, nl.ZeroTerminated("mirred"))
aopts := nl.NewRtAttrChild(table, nl.TCA_ACT_OPTIONS, nil)
mirred := nl.TcMirred{
Eaction: int32(action.MirredAction),
Ifindex: uint32(action.Ifindex),
}
toTcGen(action.Attrs(), &mirred.TcGen)
nl.NewRtAttrChild(aopts, nl.TCA_MIRRED_PARMS, mirred.Serialize())
case *BpfAction:
table := nl.NewRtAttrChild(attr, tabIndex, nil)
tabIndex++
nl.NewRtAttrChild(table, nl.TCA_ACT_KIND, nl.ZeroTerminated("bpf"))
aopts := nl.NewRtAttrChild(table, nl.TCA_ACT_OPTIONS, nil)
gen := nl.TcGen{}
toTcGen(action.Attrs(), &gen)
nl.NewRtAttrChild(aopts, nl.TCA_ACT_BPF_PARMS, gen.Serialize())
nl.NewRtAttrChild(aopts, nl.TCA_ACT_BPF_FD, nl.Uint32Attr(uint32(action.Fd)))
nl.NewRtAttrChild(aopts, nl.TCA_ACT_BPF_NAME, nl.ZeroTerminated(action.Name))
case *GenericAction:
table := nl.NewRtAttrChild(attr, tabIndex, nil)
tabIndex++
nl.NewRtAttrChild(table, nl.TCA_ACT_KIND, nl.ZeroTerminated("gact"))
aopts := nl.NewRtAttrChild(table, nl.TCA_ACT_OPTIONS, nil)
gen := nl.TcGen{}
toTcGen(action.Attrs(), &gen)
nl.NewRtAttrChild(aopts, nl.TCA_GACT_PARMS, gen.Serialize())
}
}
return nil
}
func parseActions(tables []syscall.NetlinkRouteAttr) ([]Action, error) {
var actions []Action
for _, table := range tables {
var action Action
var actionType string
aattrs, err := nl.ParseRouteAttr(table.Value)
if err != nil {
return nil, err
}
nextattr:
for _, aattr := range aattrs {
switch aattr.Attr.Type {
case nl.TCA_KIND:
actionType = string(aattr.Value[:len(aattr.Value)-1])
// only parse if the action is mirred or bpf
switch actionType {
case "mirred":
action = &MirredAction{}
case "bpf":
action = &BpfAction{}
case "gact":
action = &GenericAction{}
default:
break nextattr
}
case nl.TCA_OPTIONS:
adata, err := nl.ParseRouteAttr(aattr.Value)
if err != nil {
return nil, err
}
for _, adatum := range adata {
switch actionType {
case "mirred":
switch adatum.Attr.Type {
case nl.TCA_MIRRED_PARMS:
mirred := *nl.DeserializeTcMirred(adatum.Value)
toAttrs(&mirred.TcGen, action.Attrs())
action.(*MirredAction).ActionAttrs = ActionAttrs{}
action.(*MirredAction).Ifindex = int(mirred.Ifindex)
action.(*MirredAction).MirredAction = MirredAct(mirred.Eaction)
}
case "bpf":
switch adatum.Attr.Type {
case nl.TCA_ACT_BPF_PARMS:
gen := *nl.DeserializeTcGen(adatum.Value)
toAttrs(&gen, action.Attrs())
case nl.TCA_ACT_BPF_FD:
action.(*BpfAction).Fd = int(native.Uint32(adatum.Value[0:4]))
case nl.TCA_ACT_BPF_NAME:
action.(*BpfAction).Name = string(adatum.Value[:len(adatum.Value)-1])
}
case "gact":
switch adatum.Attr.Type {
case nl.TCA_GACT_PARMS:
gen := *nl.DeserializeTcGen(adatum.Value)
toAttrs(&gen, action.Attrs())
}
}
}
}
}
actions = append(actions, action)
}
return actions, nil
}
func parseU32Data(filter Filter, data []syscall.NetlinkRouteAttr) (bool, error) {
native = nl.NativeEndian()
u32 := filter.(*U32)
detailed := false
for _, datum := range data {
switch datum.Attr.Type {
case nl.TCA_U32_SEL:
detailed = true
sel := nl.DeserializeTcU32Sel(datum.Value)
// only parse if we have a very basic redirect
if sel.Flags&nl.TC_U32_TERMINAL == 0 || sel.Nkeys != 1 {
return detailed, nil
}
case nl.TCA_U32_ACT:
tables, err := nl.ParseRouteAttr(datum.Value)
if err != nil {
return detailed, err
}
u32.Actions, err = parseActions(tables)
if err != nil {
return detailed, err
}
for _, action := range u32.Actions {
if action, ok := action.(*MirredAction); ok {
u32.RedirIndex = int(action.Ifindex)
}
}
}
}
return detailed, nil
}
func parseFwData(filter Filter, data []syscall.NetlinkRouteAttr) (bool, error) {
native = nl.NativeEndian()
fw := filter.(*Fw)
detailed := true
for _, datum := range data {
switch datum.Attr.Type {
case nl.TCA_FW_MASK:
fw.Mask = native.Uint32(datum.Value[0:4])
case nl.TCA_FW_CLASSID:
fw.ClassId = native.Uint32(datum.Value[0:4])
case nl.TCA_FW_INDEV:
fw.InDev = string(datum.Value[:len(datum.Value)-1])
case nl.TCA_FW_POLICE:
adata, _ := nl.ParseRouteAttr(datum.Value)
for _, aattr := range adata {
switch aattr.Attr.Type {
case nl.TCA_POLICE_TBF:
fw.Police = *nl.DeserializeTcPolice(aattr.Value)
case nl.TCA_POLICE_RATE:
fw.Rtab = DeserializeRtab(aattr.Value)
case nl.TCA_POLICE_PEAKRATE:
fw.Ptab = DeserializeRtab(aattr.Value)
}
}
}
}
return detailed, nil
}
func parseBpfData(filter Filter, data []syscall.NetlinkRouteAttr) (bool, error) {
native = nl.NativeEndian()
bpf := filter.(*BpfFilter)
detailed := true
for _, datum := range data {
switch datum.Attr.Type {
case nl.TCA_BPF_FD:
bpf.Fd = int(native.Uint32(datum.Value[0:4]))
case nl.TCA_BPF_NAME:
bpf.Name = string(datum.Value[:len(datum.Value)-1])
case nl.TCA_BPF_CLASSID:
bpf.ClassId = native.Uint32(datum.Value[0:4])
case nl.TCA_BPF_FLAGS:
flags := native.Uint32(datum.Value[0:4])
if (flags & nl.TCA_BPF_FLAG_ACT_DIRECT) != 0 {
bpf.DirectAction = true
}
}
}
return detailed, nil
}
func AlignToAtm(size uint) uint {
var linksize, cells int
cells = int(size / nl.ATM_CELL_PAYLOAD)
if (size % nl.ATM_CELL_PAYLOAD) > 0 {
cells++
}
linksize = cells * nl.ATM_CELL_SIZE
return uint(linksize)
}
func AdjustSize(sz uint, mpu uint, linklayer int) uint {
if sz < mpu {
sz = mpu
}
switch linklayer {
case nl.LINKLAYER_ATM:
return AlignToAtm(sz)
default:
return sz
}
}
func CalcRtable(rate *nl.TcRateSpec, rtab [256]uint32, cellLog int, mtu uint32, linklayer int) int {
bps := rate.Rate
mpu := rate.Mpu
var sz uint
if mtu == 0 {
mtu = 2047
}
if cellLog < 0 {
cellLog = 0
for (mtu >> uint(cellLog)) > 255 {
cellLog++
}
}
for i := 0; i < 256; i++ {
sz = AdjustSize(uint((i+1)<<uint32(cellLog)), uint(mpu), linklayer)
rtab[i] = uint32(Xmittime(uint64(bps), uint32(sz)))
}
rate.CellAlign = -1
rate.CellLog = uint8(cellLog)
rate.Linklayer = uint8(linklayer & nl.TC_LINKLAYER_MASK)
return cellLog
}
func DeserializeRtab(b []byte) [256]uint32 {
var rtab [256]uint32
native := nl.NativeEndian()
r := bytes.NewReader(b)
_ = binary.Read(r, native, &rtab)
return rtab
}
func SerializeRtab(rtab [256]uint32) []byte {
native := nl.NativeEndian()
var w bytes.Buffer
_ = binary.Write(&w, native, rtab)
return w.Bytes()
}