feat: 自适应并发调度 — 网络探测 + AIMD + 参数智能推导

扫描前自动探测网络环境（RTT、丢包率、fd limit），基于探测数据推导 6 个关键参数，替代硬编码默认值： - Timeout: median_RTT + 4σ（覆盖 99.9% 正常连接） - ModuleThreadNum: target_concurrency / 30 - MaxRetries: ceil(log(0.01)/log(loss_rate))（全失败概率 <1%） - ICMPRate: 环境基准 × fd 系数 - PocNum: 跟随 ModuleThreadNum - DisablePing: 已有 ICMP 权限降级机制线程池从单信号（资源耗尽率）升级为 AIMD + 慢启动： - 慢启动：target/4 起步，500ms 翻倍 - 稳态 AIMD：健康 +5%，拥塞 ×0.5 - 双信号：资源耗尽率 + RTT 趋势（双 EMA）用户 -t 显式指定时作为 ceiling，探测仍调整其他参数。测试：单元 + 边界 + 集成 + 真实网络，core 包 580+ 用例全通过。
2026-09-25 04:31:52 +08:00 · 2026-06-12 09:46:02 +08:00
parent 683707fcd4
commit f883944b2b
21 changed files with 3287 additions and 251 deletions
@@ -0,0 +1,277 @@
+package core
+
+import (
+	"context"
+	"fmt"
+	"math"
+	"net"
+	"sort"
+	"sync"
+	"time"
+
+	"github.com/shadow1ng/fscan/common"
+	"github.com/shadow1ng/fscan/common/i18n"
+)
+
+// NetworkEnv 网络环境分类
+type NetworkEnv int
+
+const (
+	EnvLAN      NetworkEnv = iota // 内网: RTT < 5ms, 丢包 < 1%
+	EnvWAN                        // 局域网/专线: RTT 5~50ms, 丢包 < 5%
+	EnvInternet                   // 公网: RTT 50~200ms
+	EnvSlow                       // 慢速/高丢包: RTT > 200ms 或 丢包 > 10%
+)
+
+func (e NetworkEnv) String() string {
+	switch e {
+	case EnvLAN:
+		return i18n.GetText("net_env_lan")
+	case EnvWAN:
+		return i18n.GetText("net_env_wan")
+	case EnvInternet:
+		return i18n.GetText("net_env_internet")
+	default:
+		return i18n.GetText("net_env_slow")
+	}
+}
+
+// NetworkProfile 网络探测结果
+type NetworkProfile struct {
+	Env       NetworkEnv
+	RTTMin    time.Duration
+	RTTMedian time.Duration
+	RTTP95    time.Duration
+	RTTStddev time.Duration
+	LossRate  float64
+	Samples   int
+}
+
+// RecommendConcurrency 根据探测结果推荐并发参数
+// 返回 (target, ceiling)
+//   - target: 推荐的目标并发数
+//   - ceiling: 允许的最大并发数
+//
+// 如果用户显式指定了 -t，ceiling = 用户值，target 取 min(推荐值, 用户值)
+// 如果用户未指定，target 和 ceiling 均为推荐值
+func (p *NetworkProfile) RecommendConcurrency(userThreadNum int, explicit bool) (target, ceiling int) {
+	// 基于网络环境的缩放因子
+	var factor float64
+	switch p.Env {
+	case EnvLAN:
+		factor = 1.5
+	case EnvWAN:
+		factor = 1.0
+	case EnvInternet:
+		factor = 0.4
+	case EnvSlow:
+		factor = 0.15
+	}
+
+	recommended := int(float64(userThreadNum) * factor)
+	if recommended < 10 {
+		recommended = 10
+	}
+
+	// 丢包率高时进一步压缩
+	if p.LossRate > 0.05 {
+		recommended = int(float64(recommended) * (1.0 - p.LossRate))
+		if recommended < 10 {
+			recommended = 10
+		}
+	}
+
+	if explicit {
+		ceiling = userThreadNum
+		target = recommended
+		if target > ceiling {
+			target = ceiling
+		}
+	} else {
+		target = recommended
+		ceiling = recommended
+	}
+	return
+}
+
+// probePorts 探测用的端口列表（高响应率的常见端口）
+var probePorts = []int{80, 443, 22}
+
+// ProbeNetwork 探测目标网络环境
+// 从 hosts 中抽样，用低并发 TCP 连接测量 RTT 和丢包率
+// 整个过程控制在数秒内完成
+func ProbeNetwork(ctx context.Context, hosts []string, session *common.ScanSession) *NetworkProfile {
+	if len(hosts) == 0 {
+		return defaultProfile()
+	}
+
+	// 抽样：均匀分布，最多 10 个
+	samples := pickSamples(hosts, 10)
+	probeTimeout := session.Config.Timeout
+	if probeTimeout > time.Second {
+		probeTimeout = time.Second
+	}
+	if probeTimeout < 500*time.Millisecond {
+		probeTimeout = 500 * time.Millisecond
+	}
+
+	var (
+		mu       sync.Mutex
+		rtts     []time.Duration
+		failures int
+		total    int
+	)
+
+	sem := make(chan struct{}, 10)
+	var wg sync.WaitGroup
+
+	for _, host := range samples {
+		for _, port := range probePorts {
+			select {
+			case <-ctx.Done():
+				goto done
+			default:
+			}
+
+			total++
+			wg.Add(1)
+			sem <- struct{}{}
+
+			go func(h string, p int) {
+				defer func() { <-sem; wg.Done() }()
+
+				addr := fmt.Sprintf("%s:%d", h, p)
+				start := time.Now()
+				conn, err := session.DialTCP(ctx, "tcp", addr, probeTimeout)
+				rtt := time.Since(start)
+
+				mu.Lock()
+				defer mu.Unlock()
+
+				if err != nil {
+					// 连接拒绝也是有效的 RTT 样本（说明对端可达）
+					if isConnectionRefused(err) {
+						rtts = append(rtts, rtt)
+					}
+					failures++
+				} else {
+					_ = conn.Close()
+					rtts = append(rtts, rtt)
+				}
+			}(host, port)
+		}
+	}
+done:
+	wg.Wait()
+
+	return classifyNetwork(rtts, failures, total)
+}
+
+func classifyNetwork(rtts []time.Duration, failures, total int) *NetworkProfile {
+	if len(rtts) == 0 {
+		return defaultProfile()
+	}
+
+	sort.Slice(rtts, func(i, j int) bool { return rtts[i] < rtts[j] })
+
+	n := len(rtts)
+	median := rtts[n/2]
+	p95idx := int(float64(n) * 0.95)
+	if p95idx >= n {
+		p95idx = n - 1
+	}
+	p95 := rtts[p95idx]
+
+	// 标准差
+	var sum float64
+	for _, r := range rtts {
+		sum += float64(r)
+	}
+	mean := sum / float64(n)
+	var variance float64
+	for _, r := range rtts {
+		d := float64(r) - mean
+		variance += d * d
+	}
+	stddev := time.Duration(math.Sqrt(variance / float64(n)))
+
+	// 丢包率：只计算超时的（非 refused），但简化为 1 - 有效响应数/总数
+	lossRate := 1.0 - float64(n)/float64(total)
+	if lossRate < 0 {
+		lossRate = 0
+	}
+
+	// 分类
+	env := classifyEnv(median, lossRate)
+
+	return &NetworkProfile{
+		Env:       env,
+		RTTMin:    rtts[0],
+		RTTMedian: median,
+		RTTP95:    p95,
+		RTTStddev: stddev,
+		LossRate:  lossRate,
+		Samples:   n,
+	}
+}
+
+func classifyEnv(median time.Duration, lossRate float64) NetworkEnv {
+	switch {
+	case lossRate > 0.10:
+		return EnvSlow
+	case median < 5*time.Millisecond && lossRate < 0.01:
+		return EnvLAN
+	case median < 50*time.Millisecond && lossRate < 0.05:
+		return EnvWAN
+	case median < 200*time.Millisecond:
+		return EnvInternet
+	default:
+		return EnvSlow
+	}
+}
+
+func defaultProfile() *NetworkProfile {
+	return &NetworkProfile{
+		Env:       EnvWAN,
+		RTTMedian: 10 * time.Millisecond,
+		LossRate:  0,
+		Samples:   0,
+	}
+}
+
+// pickSamples 均匀抽样
+func pickSamples(hosts []string, maxSamples int) []string {
+	if maxSamples <= 0 {
+		return nil
+	}
+	n := len(hosts)
+	if n <= maxSamples {
+		return hosts
+	}
+	step := n / maxSamples
+	samples := make([]string, 0, maxSamples)
+	for i := 0; i < n && len(samples) < maxSamples; i += step {
+		samples = append(samples, hosts[i])
+	}
+	return samples
+}
+
+func isConnectionRefused(err error) bool {
+	if err == nil {
+		return false
+	}
+	// connection refused 通常包含 "refused" 关键词
+	// 在不同 OS 上表现一致
+	return containsFold(err.Error(), "refused")
+}
+
+// isTimeoutError 判断是否为超时错误
+func isTimeoutError(err error) bool {
+	if err == nil {
+		return false
+	}
+	if ne, ok := err.(net.Error); ok {
+		return ne.Timeout()
+	}
+	return containsFold(err.Error(), "timeout") || containsFold(err.Error(), "deadline")
+}