142 lines
3.4 KiB
Go
142 lines
3.4 KiB
Go
package discovery
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import (
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"context"
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"fmt"
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"net"
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"os/exec"
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"strings"
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"sync"
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"time"
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"auto-check/pkg/model"
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)
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// Scanner 网段扫描器（并发 ping 探测）
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type Scanner struct {
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CIDR string
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Timeout time.Duration // 单 IP 探测超时
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Concurrency int // 并发数，默认 30
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}
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// NewScanner 创建扫描器
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func NewScanner(cidr string, timeout time.Duration, concurrency int) *Scanner {
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if concurrency <= 0 {
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concurrency = 10
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}
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return &Scanner{
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CIDR: cidr,
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Timeout: timeout,
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Concurrency: concurrency,
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}
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}
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// Scan 并发 ping 扫描网段，返回存活设备列表（仅含 IP，MAC 留空待 SSH 阶段回填）
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func (s *Scanner) Scan() []model.Device {
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ips, ok := s.candidateIPs()
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if !ok {
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return nil
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}
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fmt.Printf("[扫描] 网段 %s，共 %d 个IP，%d 并发 ping 探测...\n", s.CIDR, len(ips), s.Concurrency)
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jobs := make(chan string, len(ips))
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results := make(chan model.Device, len(ips))
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var wg sync.WaitGroup
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for i := 0; i < s.Concurrency; i++ {
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wg.Add(1)
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go func() {
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defer wg.Done()
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for ip := range jobs {
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if s.ping(ip) {
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results <- model.Device{IP: ip, MAC: ""}
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}
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}
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}()
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}
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for _, ip := range ips {
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jobs <- ip
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}
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close(jobs)
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wg.Wait()
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close(results)
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var devices []model.Device
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for dev := range results {
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devices = append(devices, dev)
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}
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fmt.Printf("[扫描] 完成，发现 %d 台存活设备\n", len(devices))
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return devices
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}
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// candidateIPs 解析网段并生成候选 IP 列表（排除网络地址和广播地址）
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func (s *Scanner) candidateIPs() ([]string, bool) {
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_, ipnet, err := net.ParseCIDR(s.CIDR)
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if err != nil {
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fmt.Printf("[扫描] 网段解析失败: %v\n", err)
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return nil, false
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}
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ip := ipnet.IP.Mask(ipnet.Mask)
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var ips []string
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for ; ipnet.Contains(ip); inc(ip) {
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ips = append(ips, ip.String())
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}
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if len(ips) > 2 {
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ips = ips[1 : len(ips)-1]
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}
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return ips, true
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}
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// ping 探测单个 IP 是否存活（ICMP，经系统 ping 命令）。
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// 仅凭 exit code 不可靠（Windows 在某些代答/虚拟网卡场景会返回 0），
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// 因此解析输出，要求至少收到 1 个回包。
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func (s *Scanner) ping(ip string) bool {
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// ping 命令的等待超时（毫秒）：固定 1s 足够局域网探测
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const pingWait = 1000
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// context 超时设为 ping 等待的 2 倍，留足 ping 自然退出时间，
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// 避免 context 先于 ping -w 杀进程导致拿不到输出。
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ctx, cancel := context.WithTimeout(context.Background(), 2*pingWait*time.Millisecond)
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defer cancel()
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cmd := exec.CommandContext(ctx, "ping", "-n", "1", "-w", fmt.Sprintf("%d", pingWait), ip)
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out, err := cmd.Output()
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if err != nil {
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return false
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}
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return parsePingReply(string(out))
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}
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// parsePingReply 判断 ping 输出是否表示存活
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func parsePingReply(out string) bool {
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for _, line := range strings.Split(out, "\n") {
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l := strings.ToLower(strings.TrimSpace(line))
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// Windows: "Packets: Sent = 1, Received = 1, Lost = 0"
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if strings.Contains(l, "received =") {
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i := strings.Index(l, "received =")
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n := strings.TrimSpace(l[i+len("received ="):])
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// 取数字前缀
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cnt := 0
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for _, c := range n {
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if c < '0' || c > '9' {
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break
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}
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cnt = cnt*10 + int(c-'0')
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}
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return cnt >= 1
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}
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}
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return false
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}
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// inc IP 递增（原地修改，调用方负责复制）
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func inc(ip net.IP) {
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for j := len(ip) - 1; j >= 0; j-- {
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ip[j]++
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if ip[j] > 0 {
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break
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}
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}
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}
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