Improves flow handling and adds runtime stats APIs

Refactors TCP and UDP flow managers to enhance analyzer selection and flow binding accuracy, including O(1) UDP stream rebinding by 5-tuple.
Introduces runtime stats tracking for engine and ruleset operations, exposing new APIs for granular performance and error metrics.
Optimizes GeoMatcher with result caching and supports efficient geosite set matching, reducing redundant computation in ruleset expressions.

app.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"runtime"
 
 	"git.difuse.io/Difuse/Mellaris/analyzer"
 	"git.difuse.io/Difuse/Mellaris/engine"
@@ -17,6 +18,7 @@ type App struct {
 	engine        engine.Engine
 	io            gfwio.PacketIO
 	rulesetConfig *ruleset.BuiltinConfig
+	ruleset       ruleset.Ruleset
 	analyzers     []analyzer.Analyzer
 	modifiers     []modifier.Modifier
 	rulesFile     string
@@ -42,6 +44,11 @@ func New(cfg Config, opts Options) (*App, error) {
 
 	packetIO := cfg.IO.PacketIO
 	ownsIO := false
+	workerCount := effectiveWorkerCount(cfg.Workers.Count)
+	numQueues := cfg.IO.NumQueues
+	if numQueues <= 0 {
+		numQueues = workerCount
+	}
 	if packetIO == nil {
 		packetIO, err = gfwio.NewNFQueuePacketIO(gfwio.NFQueuePacketIOConfig{
 			QueueSize:    cfg.IO.QueueSize,
@@ -49,7 +56,7 @@ func New(cfg Config, opts Options) (*App, error) {
 			WriteBuffer:  cfg.IO.WriteBuffer,
 			Local:        cfg.IO.Local,
 			RST:          cfg.IO.RST,
-			NumQueues:    cfg.IO.NumQueues,
+			NumQueues:    numQueues,
 			MaxPacketLen: cfg.IO.MaxPacketLen,
 		})
 		if err != nil {
@@ -79,11 +86,13 @@ func New(cfg Config, opts Options) (*App, error) {
 		Logger:                           engineLogger,
 		IO:                               packetIO,
 		Ruleset:                          rs,
-		Workers:                          cfg.Workers.Count,
+		Workers:                          workerCount,
 		WorkerQueueSize:                  cfg.Workers.QueueSize,
 		WorkerTCPMaxBufferedPagesTotal:   cfg.Workers.TCPMaxBufferedPagesTotal,
 		WorkerTCPMaxBufferedPagesPerConn: cfg.Workers.TCPMaxBufferedPagesPerConn,
 		WorkerUDPMaxStreams:              cfg.Workers.UDPMaxStreams,
+		OverflowPolicy:                   cfg.Workers.OverflowPolicy,
+		AnalyzerSelectionMode:            cfg.Workers.AnalyzerSelectionMode,
 	}
 	eng, err := engine.NewEngine(engCfg)
 	if err != nil {
@@ -95,6 +104,7 @@ func New(cfg Config, opts Options) (*App, error) {
 		engine:        eng,
 		io:            packetIO,
 		rulesetConfig: rsConfig,
+		ruleset:       rs,
 		analyzers:     analyzers,
 		modifiers:     modifiers,
 		rulesFile:     rulesFile,
@@ -140,6 +150,17 @@ func (a *App) Engine() engine.Engine {
 	return a.engine
 }
 
+func effectiveWorkerCount(configured int) int {
+	if configured > 0 {
+		return configured
+	}
+	n := runtime.GOMAXPROCS(0)
+	if n <= 0 {
+		return 1
+	}
+	return n
+}
+
 func resolveRules(opts Options) ([]ruleset.ExprRule, string, error) {
 	if opts.RulesFile != "" && len(opts.Rules) > 0 {
 		return nil, "", ConfigError{Field: "rules", Err: errors.New("use either RulesFile or Rules")}