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firewall_nftables.go
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firewall_nftables.go
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// Copyright 2022 Liuxiangchao iwind.liu@gmail.com. All rights reserved.
//go:build linux
// +build linux
package firewalls
import (
"bytes"
"errors"
teaconst "github.com/TeaOSLab/EdgeNode/internal/const"
"github.com/TeaOSLab/EdgeNode/internal/events"
"github.com/TeaOSLab/EdgeNode/internal/firewalls/nftables"
"github.com/TeaOSLab/EdgeNode/internal/goman"
"github.com/TeaOSLab/EdgeNode/internal/remotelogs"
"github.com/iwind/TeaGo/types"
"net"
"os/exec"
"regexp"
"runtime"
"strings"
"time"
)
// check nft status, if being enabled we load it automatically
func init() {
if teaconst.IsDaemon {
return
}
if runtime.GOOS == "linux" {
var ticker = time.NewTicker(3 * time.Minute)
goman.New(func() {
for range ticker.C {
// if already ready, we break
if nftablesIsReady {
ticker.Stop()
break
}
_, err := exec.LookPath("nft")
if err == nil {
nftablesFirewall, err := NewNFTablesFirewall()
if err != nil {
continue
}
currentFirewall = nftablesFirewall
remotelogs.Println("FIREWALL", "nftables is ready")
// fire event
if nftablesFirewall.IsReady() {
events.Notify(events.EventNFTablesReady)
}
ticker.Stop()
break
}
}
})
}
}
var nftablesInstance *NFTablesFirewall
var nftablesIsReady = false
var nftablesFilters = []*nftablesTableDefinition{
// we shorten the name for table name length restriction
{Name: "edge_dft_v4", IsIPv4: true},
{Name: "edge_dft_v6", IsIPv6: true},
}
var nftablesChainName = "input"
type nftablesTableDefinition struct {
Name string
IsIPv4 bool
IsIPv6 bool
}
func (this *nftablesTableDefinition) protocol() string {
if this.IsIPv6 {
return "ip6"
}
return "ip"
}
type blockIPItem struct {
action string
ip string
timeoutSeconds int
}
func NewNFTablesFirewall() (*NFTablesFirewall, error) {
var firewall = &NFTablesFirewall{
conn: nftables.NewConn(),
dropIPQueue: make(chan *blockIPItem, 4096),
}
err := firewall.init()
if err != nil {
return nil, err
}
return firewall, nil
}
type NFTablesFirewall struct {
conn *nftables.Conn
isReady bool
version string
allowIPv4Set *nftables.Set
allowIPv6Set *nftables.Set
denyIPv4Set *nftables.Set
denyIPv6Set *nftables.Set
firewalld *Firewalld
dropIPQueue chan *blockIPItem
}
func (this *NFTablesFirewall) init() error {
// check nft
nftPath, err := exec.LookPath("nft")
if err != nil {
return errors.New("nft not found")
}
this.version = this.readVersion(nftPath)
// table
for _, tableDef := range nftablesFilters {
var family nftables.TableFamily
if tableDef.IsIPv4 {
family = nftables.TableFamilyIPv4
} else if tableDef.IsIPv6 {
family = nftables.TableFamilyIPv6
} else {
return errors.New("invalid table family: " + types.String(tableDef))
}
table, err := this.conn.GetTable(tableDef.Name, family)
if err != nil {
if nftables.IsNotFound(err) {
if tableDef.IsIPv4 {
table, err = this.conn.AddIPv4Table(tableDef.Name)
} else if tableDef.IsIPv6 {
table, err = this.conn.AddIPv6Table(tableDef.Name)
}
if err != nil {
return errors.New("create table '" + tableDef.Name + "' failed: " + err.Error())
}
} else {
return errors.New("get table '" + tableDef.Name + "' failed: " + err.Error())
}
}
if table == nil {
return errors.New("can not create table '" + tableDef.Name + "'")
}
// chain
var chainName = nftablesChainName
chain, err := table.GetChain(chainName)
if err != nil {
if nftables.IsNotFound(err) {
chain, err = table.AddAcceptChain(chainName)
if err != nil {
return errors.New("create chain '" + chainName + "' failed: " + err.Error())
}
} else {
return errors.New("get chain '" + chainName + "' failed: " + err.Error())
}
}
if chain == nil {
return errors.New("can not create chain '" + chainName + "'")
}
// allow lo
var loRuleName = []byte("lo")
_, err = chain.GetRuleWithUserData(loRuleName)
if err != nil {
if nftables.IsNotFound(err) {
_, err = chain.AddAcceptInterfaceRule("lo", loRuleName)
}
if err != nil {
return errors.New("add 'lo' rule failed: " + err.Error())
}
}
// allow set
// "allow" should be always first
for _, setAction := range []string{"allow", "deny"} {
var setName = setAction + "_set"
set, err := table.GetSet(setName)
if err != nil {
if nftables.IsNotFound(err) {
var keyType nftables.SetDataType
if tableDef.IsIPv4 {
keyType = nftables.TypeIPAddr
} else if tableDef.IsIPv6 {
keyType = nftables.TypeIP6Addr
}
set, err = table.AddSet(setName, &nftables.SetOptions{
KeyType: keyType,
HasTimeout: true,
})
if err != nil {
return errors.New("create set '" + setName + "' failed: " + err.Error())
}
} else {
return errors.New("get set '" + setName + "' failed: " + err.Error())
}
}
if set == nil {
return errors.New("can not create set '" + setName + "'")
}
if tableDef.IsIPv4 {
if setAction == "allow" {
this.allowIPv4Set = set
} else {
this.denyIPv4Set = set
}
} else if tableDef.IsIPv6 {
if setAction == "allow" {
this.allowIPv6Set = set
} else {
this.denyIPv6Set = set
}
}
// rule
var ruleName = []byte(setAction)
rule, err := chain.GetRuleWithUserData(ruleName)
if err != nil {
if nftables.IsNotFound(err) {
if tableDef.IsIPv4 {
if setAction == "allow" {
rule, err = chain.AddAcceptIPv4SetRule(setName, ruleName)
} else {
rule, err = chain.AddDropIPv4SetRule(setName, ruleName)
}
} else if tableDef.IsIPv6 {
if setAction == "allow" {
rule, err = chain.AddAcceptIPv6SetRule(setName, ruleName)
} else {
rule, err = chain.AddDropIPv6SetRule(setName, ruleName)
}
}
if err != nil {
return errors.New("add rule failed: " + err.Error())
}
} else {
return errors.New("get rule failed: " + err.Error())
}
}
if rule == nil {
return errors.New("can not create rule '" + string(ruleName) + "'")
}
}
}
this.isReady = true
nftablesIsReady = true
nftablesInstance = this
goman.New(func() {
for ipItem := range this.dropIPQueue {
switch ipItem.action {
case "drop":
err = this.DropSourceIP(ipItem.ip, ipItem.timeoutSeconds, false)
if err != nil {
remotelogs.Warn("NFTABLES", "drop ip '"+ipItem.ip+"' failed: "+err.Error())
}
}
}
})
// load firewalld
var firewalld = NewFirewalld()
if firewalld.IsReady() {
this.firewalld = firewalld
}
return nil
}
// Name 名称
func (this *NFTablesFirewall) Name() string {
return "nftables"
}
// IsReady 是否已准备被调用
func (this *NFTablesFirewall) IsReady() bool {
return this.isReady
}
// IsMock 是否为模拟
func (this *NFTablesFirewall) IsMock() bool {
return false
}
// AllowPort 允许端口
func (this *NFTablesFirewall) AllowPort(port int, protocol string) error {
if this.firewalld != nil {
return this.firewalld.AllowPort(port, protocol)
}
return nil
}
// RemovePort 删除端口
func (this *NFTablesFirewall) RemovePort(port int, protocol string) error {
if this.firewalld != nil {
return this.firewalld.RemovePort(port, protocol)
}
return nil
}
// AllowSourceIP Allow把IP加入白名单
func (this *NFTablesFirewall) AllowSourceIP(ip string) error {
var data = net.ParseIP(ip)
if data == nil {
return errors.New("invalid ip '" + ip + "'")
}
if strings.Contains(ip, ":") { // ipv6
if this.allowIPv6Set == nil {
return errors.New("ipv6 ip set is nil")
}
return this.allowIPv6Set.AddElement(data.To16(), nil)
}
// ipv4
if this.allowIPv4Set == nil {
return errors.New("ipv4 ip set is nil")
}
return this.allowIPv4Set.AddElement(data.To4(), nil)
}
// RejectSourceIP 拒绝某个源IP连接
// we did not create set for drop ip, so we reuse DropSourceIP() method here
func (this *NFTablesFirewall) RejectSourceIP(ip string, timeoutSeconds int) error {
return this.DropSourceIP(ip, timeoutSeconds, true)
}
// DropSourceIP 丢弃某个源IP数据
func (this *NFTablesFirewall) DropSourceIP(ip string, timeoutSeconds int, async bool) error {
var data = net.ParseIP(ip)
if data == nil {
return errors.New("invalid ip '" + ip + "'")
}
if async {
select {
case this.dropIPQueue <- &blockIPItem{
action: "drop",
ip: ip,
timeoutSeconds: timeoutSeconds,
}:
default:
return errors.New("drop ip queue is full")
}
return nil
}
if strings.Contains(ip, ":") { // ipv6
if this.denyIPv6Set == nil {
return errors.New("ipv6 ip set is nil")
}
return this.denyIPv6Set.AddElement(data.To16(), &nftables.ElementOptions{
Timeout: time.Duration(timeoutSeconds) * time.Second,
})
}
// ipv4
if this.denyIPv4Set == nil {
return errors.New("ipv4 ip set is nil")
}
return this.denyIPv4Set.AddElement(data.To4(), &nftables.ElementOptions{
Timeout: time.Duration(timeoutSeconds) * time.Second,
})
}
// RemoveSourceIP 删除某个源IP
func (this *NFTablesFirewall) RemoveSourceIP(ip string) error {
var data = net.ParseIP(ip)
if data == nil {
return errors.New("invalid ip '" + ip + "'")
}
if strings.Contains(ip, ":") { // ipv6
if this.denyIPv6Set != nil {
err := this.denyIPv6Set.DeleteElement(data.To16())
if err != nil {
return err
}
}
if this.allowIPv6Set != nil {
err := this.allowIPv6Set.DeleteElement(data.To16())
if err != nil {
return err
}
}
return nil
}
// ipv4
if this.allowIPv4Set != nil {
err := this.denyIPv4Set.DeleteElement(data.To4())
if err != nil {
return err
}
err = this.allowIPv4Set.DeleteElement(data.To4())
if err != nil {
return err
}
}
return nil
}
// 读取版本号
func (this *NFTablesFirewall) readVersion(nftPath string) string {
var cmd = exec.Command(nftPath, "--version")
var output = &bytes.Buffer{}
cmd.Stdout = output
err := cmd.Run()
if err != nil {
return ""
}
var outputString = output.String()
var versionMatches = regexp.MustCompile(`nftables v([\d.]+)`).FindStringSubmatch(outputString)
if len(versionMatches) <= 1 {
return ""
}
return versionMatches[1]
}