fscan/core/WebDetection.go

package core

import (
	"context"
	"net"
	"net/http"
	"strings"
	"time"
)

// WebPortDetector Web端口检测器
type WebPortDetector struct {
	// 常见Web端口列表
	commonWebPorts map[int]bool
	// HTTP检测超时时间
	httpTimeout time.Duration
}

// NewWebPortDetector 创建Web端口检测器
func NewWebPortDetector() *WebPortDetector {
	// 定义常见Web端口
	commonPorts := map[int]bool{
		80:   true, // HTTP
		443:  true, // HTTPS
		8080: true, // HTTP alternate
		8443: true, // HTTPS alternate
		8000: true, // Development server
		8888: true, // Common dev port
		9000: true, // Common dev port
		9090: true, // Common dev port
		3000: true, // Node.js dev server
		4000: true, // Ruby dev server
		5000: true, // Python dev server
		8081: true, // HTTP alternate
		8082: true, // HTTP alternate
		8083: true, // HTTP alternate
		8084: true, // HTTP alternate
		8085: true, // HTTP alternate
		8086: true, // HTTP alternate
		8087: true, // HTTP alternate
		8088: true, // HTTP alternate
		8089: true, // HTTP alternate
	}

	return &WebPortDetector{
		commonWebPorts: commonPorts,
		httpTimeout:    2 * time.Second, // 2秒超时，快速检测
	}
}

// IsWebService 检测指定主机端口是否为Web服务
func (w *WebPortDetector) IsWebService(host string, port int) bool {
	// 1. 首先检查是否为常见Web端口
	if w.commonWebPorts[port] {
		return true
	}

	// 2. 对于非常见端口，进行HTTP协议检测
	return w.detectHTTPService(host, port)
}

// IsCommonWebPort 检查是否为常见Web端口
func (w *WebPortDetector) IsCommonWebPort(port int) bool {
	return w.commonWebPorts[port]
}

// detectHTTPService 检测HTTP服务（轻量级探测）
func (w *WebPortDetector) detectHTTPService(host string, port int) bool {
	// 创建检测上下文，避免长时间阻塞
	ctx, cancel := context.WithTimeout(context.Background(), w.httpTimeout)
	defer cancel()

	// 尝试HTTP连接
	if w.tryHTTPConnection(ctx, host, port, "http") {
		return true
	}

	// 尝试HTTPS连接（对于高端口常见）
	if w.tryHTTPConnection(ctx, host, port, "https") {
		return true
	}

	return false
}

// tryHTTPConnection 尝试HTTP连接
func (w *WebPortDetector) tryHTTPConnection(ctx context.Context, host string, port int, protocol string) bool {
	url := ""
	if port == 80 && protocol == "http" {
		url = "http://" + host
	} else if port == 443 && protocol == "https" {
		url = "https://" + host
	} else {
		url = protocol + "://" + host + ":" + string(rune(port))
	}

	// 创建HTTP客户端，快速检测
	client := &http.Client{
		Timeout: w.httpTimeout,
		Transport: &http.Transport{
			DialContext: (&net.Dialer{
				Timeout: w.httpTimeout,
			}).DialContext,
			TLSHandshakeTimeout:   w.httpTimeout,
			ResponseHeaderTimeout: w.httpTimeout,
			DisableKeepAlives:     true,
		},
		CheckRedirect: func(req *http.Request, via []*http.Request) error {
			return http.ErrUseLastResponse // 不跟随重定向，加快检测速度
		},
	}

	// 发送HEAD请求，最小化网络开销
	req, err := http.NewRequestWithContext(ctx, "HEAD", url, nil)
	if err != nil {
		return false
	}

	req.Header.Set("User-Agent", "fscan-web-detector/2.0")

	resp, err := client.Do(req)
	if err != nil {
		// 检查错误类型，某些错误也表明是HTTP服务
		errStr := strings.ToLower(err.Error())
		if strings.Contains(errStr, "http") || 
		   strings.Contains(errStr, "malformed http") ||
		   strings.Contains(errStr, "server closed") {
			return true
		}
		return false
	}
	defer resp.Body.Close()

	// 任何HTTP响应都表明这是Web服务
	return resp.StatusCode > 0
}

// GetCommonWebPorts 获取常见Web端口列表
func (w *WebPortDetector) GetCommonWebPorts() []int {
	ports := make([]int, 0, len(w.commonWebPorts))
	for port := range w.commonWebPorts {
		ports = append(ports, port)
	}
	return ports
}