feat: added protected dial support, removed multi-IO support for simplicity

cmd/root.go

@@ -204,7 +204,7 @@ func (c *cliConfig) fillIO(config *engine.Config) error {
 	if err != nil {
 		return configError{Field: "io", Err: err}
 	}
-	config.IOs = []io.PacketIO{nfio}
+	config.IO = nfio
 	return nil
 }
 
@@ -247,12 +247,7 @@ func runMain(cmd *cobra.Command, args []string) {
 	if err != nil {
 		logger.Fatal("failed to parse config", zap.Error(err))
 	}
-	defer func() {
-		// Make sure to close all IOs on exit
-		for _, i := range engineConfig.IOs {
-			_ = i.Close()
-		}
-	}()
+	defer engineConfig.IO.Close() // Make sure to close IO on exit
 
 	// Ruleset
 	rawRs, err := ruleset.ExprRulesFromYAML(args[0])
@@ -263,6 +258,7 @@ func runMain(cmd *cobra.Command, args []string) {
 		Logger:               &rulesetLogger{},
 		GeoSiteFilename:      config.Ruleset.GeoSite,
 		GeoIpFilename:        config.Ruleset.GeoIp,
+		ProtectedDialContext: engineConfig.IO.ProtectedDialContext,
 	}
 	rs, err := ruleset.CompileExprRules(rawRs, analyzers, modifiers, rsConfig)
 	if err != nil {

engine/engine.go

@@ -15,7 +15,7 @@ var _ Engine = (*engine)(nil)
 
 type engine struct {
 	logger  Logger
-	ioList  []io.PacketIO
+	io      io.PacketIO
 	workers []*worker
 }
 
@@ -42,7 +42,7 @@ func NewEngine(config Config) (Engine, error) {
 	}
 	return &engine{
 		logger:  config.Logger,
-		ioList:  config.IOs,
+		io:      config.IO,
 		workers: workers,
 	}, nil
 }
@@ -58,28 +58,25 @@ func (e *engine) UpdateRuleset(r ruleset.Ruleset) error {
 
 func (e *engine) Run(ctx context.Context) error {
 	ioCtx, ioCancel := context.WithCancel(ctx)
-	defer ioCancel() // Stop workers & IOs
+	defer ioCancel() // Stop workers & IO
 
 	// Start workers
 	for _, w := range e.workers {
 		go w.Run(ioCtx)
 	}
 
-	// Register callbacks
-	errChan := make(chan error, len(e.ioList))
-	for _, i := range e.ioList {
-		ioEntry := i // Make sure dispatch() uses the correct ioEntry
-		err := ioEntry.Register(ioCtx, func(p io.Packet, err error) bool {
+	// Register IO callback
+	errChan := make(chan error, 1)
+	err := e.io.Register(ioCtx, func(p io.Packet, err error) bool {
 		if err != nil {
 			errChan <- err
 			return false
 		}
-			return e.dispatch(ioEntry, p)
+		return e.dispatch(p)
 	})
 	if err != nil {
 		return err
 	}
-	}
 
 	// Block until IO errors or context is cancelled
 	select {
@@ -91,8 +88,7 @@ func (e *engine) Run(ctx context.Context) error {
 }
 
 // dispatch dispatches a packet to a worker.
-// This must be safe for concurrent use, as it may be called from multiple IOs.
-func (e *engine) dispatch(ioEntry io.PacketIO, p io.Packet) bool {
+func (e *engine) dispatch(p io.Packet) bool {
 	data := p.Data()
 	ipVersion := data[0] >> 4
 	var layerType gopacket.LayerType
@@ -102,7 +98,7 @@ func (e *engine) dispatch(ioEntry io.PacketIO, p io.Packet) bool {
 		layerType = layers.LayerTypeIPv6
 	} else {
 		// Unsupported network layer
-		_ = ioEntry.SetVerdict(p, io.VerdictAcceptStream, nil)
+		_ = e.io.SetVerdict(p, io.VerdictAcceptStream, nil)
 		return true
 	}
 	// Load balance by stream ID
@@ -112,7 +108,7 @@ func (e *engine) dispatch(ioEntry io.PacketIO, p io.Packet) bool {
 		StreamID: p.StreamID(),
 		Packet:   packet,
 		SetVerdict: func(v io.Verdict, b []byte) error {
-			return ioEntry.SetVerdict(p, v, b)
+			return e.io.SetVerdict(p, v, b)
 		},
 	})
 	return true

engine/interface.go

@@ -18,7 +18,7 @@ type Engine interface {
 // Config is the configuration for the engine.
 type Config struct {
 	Logger  Logger
-	IOs     []io.PacketIO
+	IO      io.PacketIO
 	Ruleset ruleset.Ruleset
 
 	Workers                          int // Number of workers. Zero or negative means auto (number of CPU cores).

io/interface.go

@@ -2,6 +2,7 @@ package io
 
 import (
 	"context"
+	"net"
 )
 
 type Verdict int
@@ -29,7 +30,6 @@ type Packet interface {
 
 // PacketCallback is called for each packet received.
 // Return false to "unregister" and stop receiving packets.
-// It must be safe for concurrent use.
 type PacketCallback func(Packet, error) bool
 
 type PacketIO interface {
@@ -39,6 +39,10 @@ type PacketIO interface {
 	Register(context.Context, PacketCallback) error
 	// SetVerdict sets the verdict for a packet.
 	SetVerdict(Packet, Verdict, []byte) error
+	// ProtectedDialContext is like net.DialContext, but the connection is "protected"
+	// in the sense that the packets sent/received through the connection must bypass
+	// the packet IO and not be processed by the callback.
+	ProtectedDialContext(ctx context.Context, network, address string) (net.Conn, error)
 	// Close closes the packet IO.
 	Close() error
 }

io/nfqueue.go

@@ -5,9 +5,11 @@ import (
 	"encoding/binary"
 	"errors"
 	"fmt"
+	"net"
 	"os/exec"
 	"strconv"
 	"strings"
+	"syscall"
 
 	"github.com/coreos/go-iptables/iptables"
 	"github.com/florianl/go-nfqueue"
@@ -50,12 +52,13 @@ func generateNftRules(local, rst bool) (*nftTableSpec, error) {
 	}
 	for i := range table.Chains {
 		c := &table.Chains[i]
+		c.Rules = append(c.Rules, "meta mark $ACCEPT_CTMARK ct mark set $ACCEPT_CTMARK") // Bypass protected connections
 		c.Rules = append(c.Rules, "ct mark $ACCEPT_CTMARK counter accept")
 		if rst {
 			c.Rules = append(c.Rules, "ip protocol tcp ct mark $DROP_CTMARK counter reject with tcp reset")
 		}
 		c.Rules = append(c.Rules, "ct mark $DROP_CTMARK counter drop")
-		c.Rules = append(c.Rules, "ip protocol tcp counter queue num $QUEUE_NUM bypass")
+		c.Rules = append(c.Rules, "counter queue num $QUEUE_NUM bypass")
 	}
 	return table, nil
 }
@@ -72,6 +75,8 @@ func generateIptRules(local, rst bool) ([]iptRule, error) {
 	}
 	rules := make([]iptRule, 0, 4*len(chains))
 	for _, chain := range chains {
+		// Bypass protected connections
+		rules = append(rules, iptRule{"filter", chain, []string{"-m", "mark", "--mark", strconv.Itoa(nfqueueConnMarkAccept), "-j", "CONNMARK", "--set-mark", strconv.Itoa(nfqueueConnMarkAccept)}})
 		rules = append(rules, iptRule{"filter", chain, []string{"-m", "connmark", "--mark", strconv.Itoa(nfqueueConnMarkAccept), "-j", "ACCEPT"}})
 		if rst {
 			rules = append(rules, iptRule{"filter", chain, []string{"-p", "tcp", "-m", "connmark", "--mark", strconv.Itoa(nfqueueConnMarkDrop), "-j", "REJECT", "--reject-with", "tcp-reset"}})
@@ -96,6 +101,8 @@ type nfqueuePacketIO struct {
 	// iptables not nil = use iptables instead of nftables
 	ipt4 *iptables.IPTables
 	ipt6 *iptables.IPTables
+
+	protectedDialer *net.Dialer
 }
 
 type NFQueuePacketIOConfig struct {
@@ -153,6 +160,18 @@ func NewNFQueuePacketIO(config NFQueuePacketIOConfig) (PacketIO, error) {
 		rst:   config.RST,
 		ipt4:  ipt4,
 		ipt6:  ipt6,
+		protectedDialer: &net.Dialer{
+			Control: func(network, address string, c syscall.RawConn) error {
+				var err error
+				cErr := c.Control(func(fd uintptr) {
+					err = syscall.SetsockoptInt(int(fd), syscall.SOL_SOCKET, syscall.SO_MARK, nfqueueConnMarkAccept)
+				})
+				if cErr != nil {
+					return cErr
+				}
+				return err
+			},
+		},
 	}, nil
 }
 
@@ -239,6 +258,10 @@ func (n *nfqueuePacketIO) SetVerdict(p Packet, v Verdict, newPacket []byte) erro
 	}
 }
 
+func (n *nfqueuePacketIO) ProtectedDialContext(ctx context.Context, network, address string) (net.Conn, error) {
+	return n.protectedDialer.DialContext(ctx, network, address)
+}
+
 func (n *nfqueuePacketIO) Close() error {
 	if n.rSet {
 		if n.ipt4 != nil {

ruleset/builtins/geo/geo_matcher.go

@@ -14,14 +14,12 @@ type GeoMatcher struct {
 	ipMatcherLock   sync.Mutex
 }
 
-func NewGeoMatcher(geoSiteFilename, geoIpFilename string) (*GeoMatcher, error) {
-	geoLoader := NewDefaultGeoLoader(geoSiteFilename, geoIpFilename)
-
+func NewGeoMatcher(geoSiteFilename, geoIpFilename string) *GeoMatcher {
 	return &GeoMatcher{
-		geoLoader:      geoLoader,
+		geoLoader:      NewDefaultGeoLoader(geoSiteFilename, geoIpFilename),
 		geoSiteMatcher: make(map[string]hostMatcher),
 		geoIpMatcher:   make(map[string]hostMatcher),
-	}, nil
+	}
 }
 
 func (g *GeoMatcher) MatchGeoIp(ip, condition string) bool {

ruleset/expr.go

@@ -62,7 +62,6 @@ type exprRuleset struct {
 	Rules  []compiledExprRule
 	Ans    []analyzer.Analyzer
 	Logger Logger
-	GeoMatcher *geo.GeoMatcher
 }
 
 func (r *exprRuleset) Analyzers(info StreamInfo) []analyzer.Analyzer {
@@ -104,11 +103,7 @@ func CompileExprRules(rules []ExprRule, ans []analyzer.Analyzer, mods []modifier
 	fullAnMap := analyzersToMap(ans)
 	fullModMap := modifiersToMap(mods)
 	depAnMap := make(map[string]analyzer.Analyzer)
-	geoMatcher, err := geo.NewGeoMatcher(config.GeoSiteFilename, config.GeoIpFilename)
-	if err != nil {
-		return nil, err
-	}
-	funcMap := buildFunctionMap(geoMatcher)
+	funcMap := buildFunctionMap(config)
 	// Compile all rules and build a map of analyzers that are used by the rules.
 	for _, rule := range rules {
 		if rule.Action == "" && !rule.Log {
@@ -189,7 +184,6 @@ func CompileExprRules(rules []ExprRule, ans []analyzer.Analyzer, mods []modifier
 		Rules:  compiledRules,
 		Ans:    depAns,
 		Logger: config.Logger,
-		GeoMatcher: geoMatcher,
 	}, nil
 }
 
@@ -307,7 +301,8 @@ type Function struct {
 	Types     []reflect.Type
 }
 
-func buildFunctionMap(geoMatcher *geo.GeoMatcher) map[string]*Function {
+func buildFunctionMap(config *BuiltinConfig) map[string]*Function {
+	geoMatcher := geo.NewGeoMatcher(config.GeoSiteFilename, config.GeoIpFilename)
 	return map[string]*Function{
 		"geoip": {
 			InitFunc:  geoMatcher.LoadGeoIP,
@@ -342,39 +337,41 @@ func buildFunctionMap(geoMatcher *geo.GeoMatcher) map[string]*Function {
 			Func: func(params ...any) (any, error) {
 				return builtins.MatchCIDR(params[0].(string), params[1].(*net.IPNet)), nil
 			},
-			Types: []reflect.Type{reflect.TypeOf((func(string, string) bool)(nil)), reflect.TypeOf(builtins.MatchCIDR)},
+			Types: []reflect.Type{reflect.TypeOf(builtins.MatchCIDR)},
 		},
 		"lookup": {
 			InitFunc: nil,
 			PatchFunc: func(args *[]ast.Node) error {
-				if len(*args) < 2 {
-					// Second argument (DNS server) is optional
-					return nil
-				}
-				serverStr, ok := (*args)[1].(*ast.StringNode)
+				var serverStr *ast.StringNode
+				if len(*args) > 1 {
+					// Has the optional server argument
+					var ok bool
+					serverStr, ok = (*args)[1].(*ast.StringNode)
 					if !ok {
 						return fmt.Errorf("lookup: invalid argument type")
 					}
+				}
 				r := &net.Resolver{
 					Dial: func(ctx context.Context, network, address string) (net.Conn, error) {
-						return net.Dial(network, serverStr.Value)
+						if serverStr != nil {
+							address = serverStr.Value
+						}
+						return config.ProtectedDialContext(ctx, network, address)
 					},
 				}
+				if len(*args) > 1 {
 					(*args)[1] = &ast.ConstantNode{Value: r}
+				} else {
+					*args = append(*args, &ast.ConstantNode{Value: r})
+				}
 				return nil
 			},
 			Func: func(params ...any) (any, error) {
-				ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+				ctx, cancel := context.WithTimeout(context.Background(), 4*time.Second)
 				defer cancel()
-				if len(params) < 2 {
-					return net.DefaultResolver.LookupHost(ctx, params[0].(string))
-				} else {
 				return params[1].(*net.Resolver).LookupHost(ctx, params[0].(string))
-				}
 			},
 			Types: []reflect.Type{
-				reflect.TypeOf((func(string, string) []string)(nil)),
-				reflect.TypeOf((func(string) []string)(nil)),
 				reflect.TypeOf((func(string, *net.Resolver) []string)(nil)),
 			},
 		},

ruleset/interface.go

@@ -1,6 +1,7 @@
 package ruleset
 
 import (
+	"context"
 	"net"
 	"strconv"
 
@@ -103,4 +104,5 @@ type BuiltinConfig struct {
 	Logger               Logger
 	GeoSiteFilename      string
 	GeoIpFilename        string
+	ProtectedDialContext func(ctx context.Context, network, address string) (net.Conn, error)
 }