实现基础的DDoS防护

internal/firewalls/ddos_protection.go

@@ -0,0 +1,494 @@
+// Copyright 2022 Liuxiangchao iwind.liu@gmail.com. All rights reserved.
+//go:build linux
+// +build linux
+
+package firewalls
+
+import (
+	"bytes"
+	"encoding/json"
+	"errors"
+	"github.com/TeaOSLab/EdgeCommon/pkg/nodeconfigs"
+	"github.com/TeaOSLab/EdgeCommon/pkg/serverconfigs/ddosconfigs"
+	"github.com/TeaOSLab/EdgeNode/internal/events"
+	"github.com/TeaOSLab/EdgeNode/internal/firewalls/nftables"
+	"github.com/TeaOSLab/EdgeNode/internal/remotelogs"
+	"github.com/TeaOSLab/EdgeNode/internal/utils"
+	"github.com/TeaOSLab/EdgeNode/internal/zero"
+	"github.com/iwind/TeaGo/lists"
+	"github.com/iwind/TeaGo/types"
+	"net"
+	"os/exec"
+	"strings"
+)
+
+var SharedDDoSProtectionManager = NewDDoSProtectionManager()
+
+func init() {
+	events.On(events.EventReload, func() {
+		if nftablesInstance == nil {
+			return
+		}
+
+		nodeConfig, _ := nodeconfigs.SharedNodeConfig()
+		if nodeConfig != nil {
+			err := SharedDDoSProtectionManager.Apply(nodeConfig.DDOSProtection)
+			if err != nil {
+				remotelogs.Error("FIREWALL", "apply DDoS protection failed: "+err.Error())
+			}
+		}
+	})
+
+	events.On(events.EventNFTablesReady, func() {
+		nodeConfig, _ := nodeconfigs.SharedNodeConfig()
+		if nodeConfig != nil {
+			err := SharedDDoSProtectionManager.Apply(nodeConfig.DDOSProtection)
+			if err != nil {
+				remotelogs.Error("FIREWALL", "apply DDoS protection failed: "+err.Error())
+			}
+		}
+	})
+}
+
+// DDoSProtectionManager DDoS防护
+type DDoSProtectionManager struct {
+	nftPath string
+
+	lastAllowIPList []string
+	lastConfig      []byte
+}
+
+// NewDDoSProtectionManager 获取新对象
+func NewDDoSProtectionManager() *DDoSProtectionManager {
+	nftPath, _ := exec.LookPath("nft")
+
+	return &DDoSProtectionManager{
+		nftPath: nftPath,
+	}
+}
+
+// Apply 应用配置
+func (this *DDoSProtectionManager) Apply(config *ddosconfigs.ProtectionConfig) error {
+	// 同集群节点IP白名单
+	var allowIPListChanged = false
+	nodeConfig, _ := nodeconfigs.SharedNodeConfig()
+	if nodeConfig != nil {
+		var allowIPList = nodeConfig.AllowedIPs
+		if !utils.ContainsSameStrings(allowIPList, this.lastAllowIPList) {
+			allowIPListChanged = true
+			this.lastAllowIPList = allowIPList
+		}
+	}
+
+	// 对比配置
+	configJSON, err := json.Marshal(config)
+	if err != nil {
+		return errors.New("encode config to json failed: " + err.Error())
+	}
+	if !allowIPListChanged && bytes.Equal(this.lastConfig, configJSON) {
+		return nil
+	}
+	remotelogs.Println("FIREWALL", "change DDoS protection config")
+
+	if len(this.nftPath) == 0 {
+		return errors.New("can not find nft command")
+	}
+
+	if nftablesInstance == nil {
+		return errors.New("nftables instance should not be nil")
+	}
+
+	if config == nil {
+		// TCP
+		err := this.removeTCPRules()
+		if err != nil {
+			return err
+		}
+
+		// TODO other protocols
+
+		return nil
+	}
+
+	// TCP
+	if config.TCP == nil {
+		err := this.removeTCPRules()
+		if err != nil {
+			return err
+		}
+	} else {
+		// allow ip list
+		var allowIPList = []string{}
+		for _, ipConfig := range config.TCP.AllowIPList {
+			allowIPList = append(allowIPList, ipConfig.IP)
+		}
+		for _, ip := range this.lastAllowIPList {
+			if !lists.ContainsString(allowIPList, ip) {
+				allowIPList = append(allowIPList, ip)
+			}
+		}
+		err = this.updateAllowIPList(allowIPList)
+		if err != nil {
+			return err
+		}
+
+		// tcp
+		if config.TCP.IsOn {
+			err := this.addTCPRules(config.TCP)
+			if err != nil {
+				return err
+			}
+		} else {
+			err := this.removeTCPRules()
+			if err != nil {
+				return err
+			}
+		}
+	}
+
+	this.lastConfig = configJSON
+
+	return nil
+}
+
+// 添加TCP规则
+func (this *DDoSProtectionManager) addTCPRules(tcpConfig *ddosconfigs.TCPConfig) error {
+	var ports = []int32{}
+	for _, portConfig := range tcpConfig.Ports {
+		if !lists.ContainsInt32(ports, portConfig.Port) {
+			ports = append(ports, portConfig.Port)
+		}
+	}
+	if len(ports) == 0 {
+		ports = []int32{80, 443}
+	}
+
+	for _, filter := range nftablesFilters {
+		chain, oldRules, err := this.getRules(filter)
+		if err != nil {
+			return errors.New("get old rules failed: " + err.Error())
+		}
+
+		var protocol = filter.protocol()
+
+		// max connections
+		var maxConnections = tcpConfig.MaxConnections
+		if maxConnections <= 0 {
+			maxConnections = nodeconfigs.DefaultTCPMaxConnections
+			if maxConnections <= 0 {
+				maxConnections = 100000
+			}
+		}
+
+		// max connections per ip
+		var maxConnectionsPerIP = tcpConfig.MaxConnectionsPerIP
+		if maxConnectionsPerIP <= 0 {
+			maxConnectionsPerIP = nodeconfigs.DefaultTCPMaxConnectionsPerIP
+			if maxConnectionsPerIP <= 0 {
+				maxConnectionsPerIP = 100000
+			}
+		}
+
+		// new connections rate
+		var newConnectionsRate = tcpConfig.NewConnectionsRate
+		if newConnectionsRate <= 0 {
+			newConnectionsRate = nodeconfigs.DefaultTCPNewConnectionsRate
+			if newConnectionsRate <= 0 {
+				newConnectionsRate = 100000
+			}
+		}
+
+		// 检查是否有变化
+		var hasChanges = false
+		for _, port := range ports {
+			if !this.existsRule(oldRules, []string{"tcp", types.String(port), "maxConnections", types.String(maxConnections)}) {
+				hasChanges = true
+				break
+			}
+			if !this.existsRule(oldRules, []string{"tcp", types.String(port), "maxConnectionsPerIP", types.String(maxConnectionsPerIP)}) {
+				hasChanges = true
+				break
+			}
+			if !this.existsRule(oldRules, []string{"tcp", types.String(port), "newConnectionsRate", types.String(newConnectionsRate)}) {
+				hasChanges = true
+				break
+			}
+		}
+
+		if !hasChanges {
+			// 检查是否有多余的端口
+			var oldPorts = this.getTCPPorts(oldRules)
+			if !this.eqPorts(ports, oldPorts) {
+				hasChanges = true
+			}
+		}
+
+		if !hasChanges {
+			return nil
+		}
+
+		// 先清空所有相关规则
+		err = this.removeOldTCPRules(chain, oldRules)
+		if err != nil {
+			return errors.New("delete old rules failed: " + err.Error())
+		}
+
+		// 添加新规则
+		for _, port := range ports {
+			if maxConnections > 0 {
+				var cmd = exec.Command(this.nftPath, "add", "rule", protocol, filter.Name, nftablesChainName, "tcp", "dport", types.String(port), "ct", "count", "over", types.String(maxConnections), "counter", "drop", "comment", this.encodeUserData([]string{"tcp", types.String(port), "maxConnections", types.String(maxConnections)}))
+				err := cmd.Run()
+				if err != nil {
+					return errors.New("add nftables rule '" + cmd.String() + "' failed: " + err.Error())
+				}
+			}
+
+			if maxConnectionsPerIP > 0 {
+				var cmd = exec.Command(this.nftPath, "add", "rule", protocol, filter.Name, nftablesChainName, "tcp", "dport", types.String(port), "meter", "meter-"+protocol+"-"+types.String(port)+"-max-connections", "{ "+protocol+" saddr ct count over "+types.String(maxConnectionsPerIP)+" }", "counter", "drop", "comment", this.encodeUserData([]string{"tcp", types.String(port), "maxConnectionsPerIP", types.String(maxConnectionsPerIP)}))
+				var stderr = &bytes.Buffer{}
+				cmd.Stderr = stderr
+				err := cmd.Run()
+				if err != nil {
+					return errors.New("add nftables rule '" + cmd.String() + "' failed: " + err.Error() + " (" + stderr.String() + ")")
+				}
+			}
+
+			if newConnectionsRate > 0 {
+				// TODO 思考是否有惩罚机制
+				var cmd = exec.Command(this.nftPath, "add", "rule", protocol, filter.Name, nftablesChainName, "tcp", "dport", types.String(port), "ct", "state", "new", "meter", "meter-"+protocol+"-"+types.String(port)+"-new-connections-rate", "{ "+protocol+" saddr limit rate over "+types.String(newConnectionsRate)+"/minute burst "+types.String(newConnectionsRate+3)+" packets }" /**"add", "@deny_set", "{"+protocol+" saddr}",**/, "counter", "drop", "comment", this.encodeUserData([]string{"tcp", types.String(port), "newConnectionsRate", types.String(newConnectionsRate)}))
+				var stderr = &bytes.Buffer{}
+				cmd.Stderr = stderr
+				err := cmd.Run()
+				if err != nil {
+					return errors.New("add nftables rule '" + cmd.String() + "' failed: " + err.Error() + " (" + stderr.String() + ")")
+				}
+			}
+		}
+	}
+
+	return nil
+}
+
+// 删除TCP规则
+func (this *DDoSProtectionManager) removeTCPRules() error {
+	for _, filter := range nftablesFilters {
+		chain, rules, err := this.getRules(filter)
+
+		// TCP
+		err = this.removeOldTCPRules(chain, rules)
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+// 组合user data
+// 数据中不能包含字母、数字、下划线以外的数据
+func (this *DDoSProtectionManager) encodeUserData(attrs []string) string {
+	if attrs == nil {
+		return ""
+	}
+
+	return "ZZ" + strings.Join(attrs, "_") + "ZZ"
+}
+
+// 解码user data
+func (this *DDoSProtectionManager) decodeUserData(data []byte) []string {
+	if len(data) == 0 {
+		return nil
+	}
+
+	var dataCopy = make([]byte, len(data))
+	copy(dataCopy, data)
+
+	var separatorLen = 2
+	var index1 = bytes.Index(dataCopy, []byte{'Z', 'Z'})
+	if index1 < 0 {
+		return nil
+	}
+
+	dataCopy = dataCopy[index1+separatorLen:]
+	var index2 = bytes.LastIndex(dataCopy, []byte{'Z', 'Z'})
+	if index2 < 0 {
+		return nil
+	}
+
+	var s = string(dataCopy[:index2])
+	var pieces = strings.Split(s, "_")
+	for index, piece := range pieces {
+		pieces[index] = strings.TrimSpace(piece)
+	}
+	return pieces
+}
+
+// 清除规则
+func (this *DDoSProtectionManager) removeOldTCPRules(chain *nftables.Chain, rules []*nftables.Rule) error {
+	for _, rule := range rules {
+		var pieces = this.decodeUserData(rule.UserData())
+		if len(pieces) != 4 {
+			continue
+		}
+		if pieces[0] != "tcp" {
+			continue
+		}
+		switch pieces[2] {
+		case "maxConnections", "maxConnectionsPerIP", "newConnectionsRate":
+			err := chain.DeleteRule(rule)
+			if err != nil {
+				return err
+			}
+		}
+	}
+
+	return nil
+}
+
+// 根据参数检查规则是否存在
+func (this *DDoSProtectionManager) existsRule(rules []*nftables.Rule, attrs []string) (exists bool) {
+	if len(attrs) == 0 {
+		return false
+	}
+	for _, oldRule := range rules {
+		var pieces = this.decodeUserData(oldRule.UserData())
+		if len(attrs) != len(pieces) {
+			continue
+		}
+		var isSame = true
+		for index, piece := range pieces {
+			if strings.TrimSpace(piece) != attrs[index] {
+				isSame = false
+				break
+			}
+		}
+		if isSame {
+			return true
+		}
+	}
+	return false
+}
+
+// 获取规则中的端口号
+func (this *DDoSProtectionManager) getTCPPorts(rules []*nftables.Rule) []int32 {
+	var ports = []int32{}
+	for _, rule := range rules {
+		var pieces = this.decodeUserData(rule.UserData())
+		if len(pieces) != 4 {
+			continue
+		}
+		if pieces[0] != "tcp" {
+			continue
+		}
+		var port = types.Int32(pieces[1])
+		if port > 0 && !lists.ContainsInt32(ports, port) {
+			ports = append(ports, port)
+		}
+	}
+	return ports
+}
+
+// 检查端口是否一样
+func (this *DDoSProtectionManager) eqPorts(ports1 []int32, ports2 []int32) bool {
+	if len(ports1) != len(ports2) {
+		return false
+	}
+
+	var portMap = map[int32]bool{}
+	for _, port := range ports2 {
+		portMap[port] = true
+	}
+
+	for _, port := range ports1 {
+		_, ok := portMap[port]
+		if !ok {
+			return false
+		}
+	}
+	return true
+}
+
+// 查找Table
+func (this *DDoSProtectionManager) getTable(filter *nftablesTableDefinition) (*nftables.Table, error) {
+	var family nftables.TableFamily
+	if filter.IsIPv4 {
+		family = nftables.TableFamilyIPv4
+	} else if filter.IsIPv6 {
+		family = nftables.TableFamilyIPv6
+	} else {
+		return nil, errors.New("table '" + filter.Name + "' should be IPv4 or IPv6")
+	}
+	return nftablesInstance.conn.GetTable(filter.Name, family)
+}
+
+// 查找所有规则
+func (this *DDoSProtectionManager) getRules(filter *nftablesTableDefinition) (*nftables.Chain, []*nftables.Rule, error) {
+	table, err := this.getTable(filter)
+	if err != nil {
+		return nil, nil, errors.New("get table failed: " + err.Error())
+	}
+	chain, err := table.GetChain(nftablesChainName)
+	if err != nil {
+		return nil, nil, errors.New("get chain failed: " + err.Error())
+	}
+	rules, err := chain.GetRules()
+	return chain, rules, err
+}
+
+// 更新白名单
+func (this *DDoSProtectionManager) updateAllowIPList(allIPList []string) error {
+	if nftablesInstance == nil {
+		return nil
+	}
+
+	var allMap = map[string]zero.Zero{}
+	for _, ip := range allIPList {
+		allMap[ip] = zero.New()
+	}
+
+	for _, set := range []*nftables.Set{nftablesInstance.allowIPv4Set, nftablesInstance.allowIPv6Set} {
+		var isIPv4 = set == nftablesInstance.allowIPv4Set
+		var isIPv6 = !isIPv4
+
+		// 现有的
+		oldList, err := set.GetIPElements()
+		if err != nil {
+			return err
+		}
+		var oldMap = map[string]zero.Zero{} // ip=> zero
+		for _, ip := range oldList {
+			oldMap[ip] = zero.New()
+
+			if (utils.IsIPv4(ip) && isIPv4) || (utils.IsIPv6(ip) && isIPv6) {
+				_, ok := allMap[ip]
+				if !ok {
+					// 不存在则删除
+					err = set.DeleteIPElement(ip)
+					if err != nil {
+						return errors.New("delete ip element '" + ip + "' failed: " + err.Error())
+					}
+				}
+			}
+		}
+
+		// 新增的
+		for _, ip := range allIPList {
+			var ipObj = net.ParseIP(ip)
+			if ipObj == nil {
+				continue
+			}
+			if (utils.IsIPv4(ip) && isIPv4) || (utils.IsIPv6(ip) && isIPv6) {
+				_, ok := oldMap[ip]
+				if !ok {
+					// 不存在则添加
+					err = set.AddIPElement(ip, nil)
+					if err != nil {
+						return errors.New("add ip '" + ip + "' failed: " + err.Error())
+					}
+				}
+			}
+		}
+	}
+
+	return nil
+}