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Implement AddGenerationalMonitor to deliver monitor events in batches (#283)

This commit is contained in:
_|+ 2024-11-09 12:07:36 +01:00 committed by GitHub
parent ed578af895
commit 51c44dcf05
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GPG Key ID: B5690EEEBB952194
3 changed files with 180 additions and 55 deletions
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45
gen.go Normal file
View File

@ -0,0 +1,45 @@
package nftables
import (
"encoding/binary"
"fmt"
"github.com/mdlayher/netlink"
"golang.org/x/sys/unix"
)
type GenMsg struct {
ID uint32
ProcPID uint32
ProcComm string // [16]byte - max 16bytes - kernel TASK_COMM_LEN
}
var genHeaderType = netlink.HeaderType((unix.NFNL_SUBSYS_NFTABLES << 8) | unix.NFT_MSG_NEWGEN)
func genFromMsg(msg netlink.Message) (*GenMsg, error) {
if got, want := msg.Header.Type, genHeaderType; got != want {
return nil, fmt.Errorf("unexpected header type: got %v, want %v", got, want)
}
ad, err := netlink.NewAttributeDecoder(msg.Data[4:])
if err != nil {
return nil, err
}
ad.ByteOrder = binary.BigEndian
msgOut := &GenMsg{}
for ad.Next() {
switch ad.Type() {
case unix.NFTA_GEN_ID:
msgOut.ID = ad.Uint32()
case unix.NFTA_GEN_PROC_PID:
msgOut.ProcPID = ad.Uint32()
case unix.NFTA_GEN_PROC_NAME:
msgOut.ProcComm = ad.String()
default:
return nil, fmt.Errorf("Unknown attribute: %d %v\n", ad.Type(), ad.Bytes())
}
}
if err := ad.Err(); err != nil {
return nil, err
}
return msgOut, nil
}

80
monitor.go
View File

@ -116,11 +116,17 @@ const (
// nftables.MonitorEventTypeNewTable, you can access the corresponding table
// details via Data.(*nftables.Table).
type MonitorEvent struct {
Header netlink.Header
Type MonitorEventType
Data any
Error error
}
type MonitorEvents struct {
GeneratedBy *MonitorEvent
Changes []*MonitorEvent
}
const (
monitorOK = iota
monitorClosed
@ -139,7 +145,7 @@ type Monitor struct {
// mu covers eventCh and status
mu sync.Mutex
eventCh chan *MonitorEvent
eventCh chan *MonitorEvents
status int
}
@ -147,7 +153,7 @@ type MonitorOption func(*Monitor)
func WithMonitorEventBuffer(size int) MonitorOption {
return func(monitor *Monitor) {
monitor.eventCh = make(chan *MonitorEvent, size)
monitor.eventCh = make(chan *MonitorEvents, size)
}
}
@ -177,7 +183,7 @@ func NewMonitor(opts ...MonitorOption) *Monitor {
opt(monitor)
}
if monitor.eventCh == nil {
monitor.eventCh = make(chan *MonitorEvent)
monitor.eventCh = make(chan *MonitorEvents)
}
objects, ok := monitorFlags[monitor.action]
if !ok {
@ -192,6 +198,8 @@ func NewMonitor(opts ...MonitorOption) *Monitor {
}
func (monitor *Monitor) monitor() {
var changesEvents []*MonitorEvent
for {
msgs, err := monitor.conn.Receive()
if err != nil {
@ -199,13 +207,21 @@ func (monitor *Monitor) monitor() {
// ignore the error that be closed
break
} else {
// any other errors will be send to user, and then to close eventCh
// any other errors will be sent to user, and then to close eventCh
event := &MonitorEvent{
Type: MonitorEventTypeOOB,
Data: nil,
Error: err,
}
monitor.eventCh <- event
changesEvents = append(changesEvents, event)
monitor.eventCh <- &MonitorEvents{
GeneratedBy: event,
Changes: changesEvents,
}
changesEvents = nil
break
}
}
@ -224,51 +240,73 @@ func (monitor *Monitor) monitor() {
Type: MonitorEventType(msgType),
Data: table,
Error: err,
Header: msg.Header,
}
monitor.eventCh <- event
changesEvents = append(changesEvents, event)
case unix.NFT_MSG_NEWCHAIN, unix.NFT_MSG_DELCHAIN:
chain, err := chainFromMsg(msg)
event := &MonitorEvent{
Type: MonitorEventType(msgType),
Data: chain,
Error: err,
Header: msg.Header,
}
monitor.eventCh <- event
changesEvents = append(changesEvents, event)
case unix.NFT_MSG_NEWRULE, unix.NFT_MSG_DELRULE:
rule, err := parseRuleFromMsg(msg)
event := &MonitorEvent{
Type: MonitorEventType(msgType),
Data: rule,
Error: err,
Header: msg.Header,
}
monitor.eventCh <- event
changesEvents = append(changesEvents, event)
case unix.NFT_MSG_NEWSET, unix.NFT_MSG_DELSET:
set, err := setsFromMsg(msg)
event := &MonitorEvent{
Type: MonitorEventType(msgType),
Data: set,
Error: err,
Header: msg.Header,
}
monitor.eventCh <- event
changesEvents = append(changesEvents, event)
case unix.NFT_MSG_NEWSETELEM, unix.NFT_MSG_DELSETELEM:
elems, err := elementsFromMsg(uint8(TableFamilyUnspecified), msg)
event := &MonitorEvent{
Type: MonitorEventType(msgType),
Data: elems,
Error: err,
Header: msg.Header,
}
monitor.eventCh <- event
changesEvents = append(changesEvents, event)
case unix.NFT_MSG_NEWOBJ, unix.NFT_MSG_DELOBJ:
obj, err := objFromMsg(msg, true)
event := &MonitorEvent{
Type: MonitorEventType(msgType),
Data: obj,
Error: err,
Header: msg.Header,
}
monitor.eventCh <- event
changesEvents = append(changesEvents, event)
case unix.NFT_MSG_NEWGEN:
gen, err := genFromMsg(msg)
event := &MonitorEvent{
Type: MonitorEventType(msgType),
Data: gen,
Error: err,
Header: msg.Header,
}
monitor.eventCh <- &MonitorEvents{
GeneratedBy: event,
Changes: changesEvents,
}
changesEvents = nil
}
}
}
monitor.mu.Lock()
defer monitor.mu.Unlock()
@ -294,6 +332,26 @@ func (monitor *Monitor) Close() error {
// Caller may receive a MonitorEventTypeOOB event which contains an error we didn't
// handle, for now.
func (cc *Conn) AddMonitor(monitor *Monitor) (chan *MonitorEvent, error) {
generationalEventCh, err := cc.AddGenerationalMonitor(monitor)
if err != nil {
return nil, err
}
eventCh := make(chan *MonitorEvent)
go func() {
defer close(eventCh)
for monitorEvents := range generationalEventCh {
for _, event := range monitorEvents.Changes {
eventCh <- event
}
}
}()
return eventCh, nil
}
func (cc *Conn) AddGenerationalMonitor(monitor *Monitor) (chan *MonitorEvents, error) {
conn, closer, err := cc.netlinkConn()
if err != nil {
return nil, err

48
monitor_test.go
View File

@ -4,6 +4,8 @@ import (
"fmt"
"log"
"net"
"os"
"path/filepath"
"sync"
"sync/atomic"
"testing"
@ -21,19 +23,21 @@ func ExampleNewMonitor() {
mon := nftables.NewMonitor()
defer mon.Close()
events, err := conn.AddMonitor(mon)
events, err := conn.AddGenerationalMonitor(mon)
if err != nil {
log.Fatal(err)
}
for ev := range events {
log.Printf("ev: %+v, data = %T", ev, ev.Data)
switch ev.Type {
case nftables.MonitorEventTypeNewTable:
log.Printf("data = %+v", ev.Data.(*nftables.Table))
log.Printf("ev: %+v, data = %T", ev, ev.Changes)
for _, change := range ev.Changes {
switch change.Type {
case nftables.MonitorEventTypeNewTable:
log.Printf("data = %+v", change.Data.(*nftables.Table))
// …more cases if needed…
}
}
}
}
func TestMonitor(t *testing.T) {
@ -44,10 +48,9 @@ func TestMonitor(t *testing.T) {
// Clear all rules at the beginning + end of the test.
c.FlushRuleset()
defer c.FlushRuleset()
// default to monitor all
monitor := nftables.NewMonitor()
events, err := c.AddMonitor(monitor)
events, err := c.AddGenerationalMonitor(monitor)
if err != nil {
t.Fatal(err)
}
@ -58,6 +61,7 @@ func TestMonitor(t *testing.T) {
var gotRule *nftables.Rule
wg := sync.WaitGroup{}
wg.Add(1)
var errMonitor error
go func() {
defer wg.Done()
count := int32(0)
@ -66,25 +70,37 @@ func TestMonitor(t *testing.T) {
if !ok {
return
}
if event.Error != nil {
err = fmt.Errorf("monitor err: %s", event.Error)
genMsg := event.GeneratedBy.Data.(*nftables.GenMsg)
fileName := filepath.Base(os.Args[0])
if genMsg.ProcComm != fileName {
errMonitor = fmt.Errorf("procComm: %s, want: %s", genMsg.ProcComm, fileName)
return
}
switch event.Type {
for _, change := range event.Changes {
if change.Error != nil {
errMonitor = fmt.Errorf("monitor err: %s", change.Error)
return
}
switch change.Type {
case nftables.MonitorEventTypeNewTable:
gotTable = event.Data.(*nftables.Table)
gotTable = change.Data.(*nftables.Table)
atomic.AddInt32(&count, 1)
case nftables.MonitorEventTypeNewChain:
gotChain = event.Data.(*nftables.Chain)
gotChain = change.Data.(*nftables.Chain)
atomic.AddInt32(&count, 1)
case nftables.MonitorEventTypeNewRule:
gotRule = event.Data.(*nftables.Rule)
gotRule = change.Data.(*nftables.Rule)
atomic.AddInt32(&count, 1)
}
if atomic.LoadInt32(&count) == 3 {
return
}
}
}
}()
nat := c.AddTable(&nftables.Table{
@ -126,7 +142,13 @@ func TestMonitor(t *testing.T) {
if err := c.Flush(); err != nil {
t.Fatal(err)
}
wg.Wait()
if errMonitor != nil {
t.Fatal("monitor err", errMonitor)
}
if gotTable.Family != nat.Family || gotTable.Name != nat.Name {
t.Fatal("no want table", gotTable.Family, gotTable.Name)
}