macOS 下 Snipaste 每隔 5 秒钟左右就扫描一次 Wi-Fi

[sunlei]

最近发现本机到网关的延迟周期性的升高，很有规律，大约每 10 秒就会出现：

64 bytes from *.*.*.*: icmp_seq=347 ttl=64 time=1.648 ms
64 bytes from *.*.*.*: icmp_seq=348 ttl=64 time=1.242 ms
64 bytes from *.*.*.*: icmp_seq=349 ttl=64 time=1.319 ms
64 bytes from *.*.*.*: icmp_seq=350 ttl=64 time=2.116 ms
64 bytes from *.*.*.*: icmp_seq=351 ttl=64 time=29.329 ms
64 bytes from *.*.*.*: icmp_seq=352 ttl=64 time=12.116 ms
64 bytes from *.*.*.*: icmp_seq=353 ttl=64 time=64.836 ms
64 bytes from *.*.*.*: icmp_seq=354 ttl=64 time=112.894 ms
64 bytes from *.*.*.*: icmp_seq=355 ttl=64 time=1.143 ms
64 bytes from *.*.*.*: icmp_seq=356 ttl=64 time=3.535 ms
64 bytes from *.*.*.*: icmp_seq=357 ttl=64 time=2.123 ms
64 bytes from *.*.*.*: icmp_seq=358 ttl=64 time=2.181 ms
64 bytes from *.*.*.*: icmp_seq=359 ttl=64 time=1.299 ms
64 bytes from *.*.*.*: icmp_seq=360 ttl=64 time=1.290 ms
64 bytes from *.*.*.*: icmp_seq=361 ttl=64 time=1.476 ms
64 bytes from *.*.*.*: icmp_seq=362 ttl=64 time=1.422 ms
64 bytes from *.*.*.*: icmp_seq=363 ttl=64 time=1.277 ms
64 bytes from *.*.*.*: icmp_seq=364 ttl=64 time=1.224 ms
64 bytes from *.*.*.*: icmp_seq=365 ttl=64 time=1.342 ms
64 bytes from *.*.*.*: icmp_seq=366 ttl=64 time=1.271 ms
64 bytes from *.*.*.*: icmp_seq=367 ttl=64 time=17.473 ms
64 bytes from *.*.*.*: icmp_seq=368 ttl=64 time=58.126 ms
64 bytes from *.*.*.*: icmp_seq=369 ttl=64 time=1.054 ms
64 bytes from *.*.*.*: icmp_seq=370 ttl=64 time=2.421 ms
64 bytes from *.*.*.*: icmp_seq=371 ttl=64 time=1.254 ms
64 bytes from *.*.*.*: icmp_seq=372 ttl=64 time=2.591 ms
64 bytes from *.*.*.*: icmp_seq=373 ttl=64 time=1.273 ms
64 bytes from *.*.*.*: icmp_seq=374 ttl=64 time=1.307 ms
64 bytes from *.*.*.*: icmp_seq=375 ttl=64 time=2.319 ms
64 bytes from *.*.*.*: icmp_seq=376 ttl=64 time=1.532 ms
64 bytes from *.*.*.*: icmp_seq=377 ttl=64 time=2.146 ms
64 bytes from *.*.*.*: icmp_seq=378 ttl=64 time=1.903 ms
64 bytes from *.*.*.*: icmp_seq=379 ttl=64 time=42.457 ms
64 bytes from *.*.*.*: icmp_seq=380 ttl=64 time=108.357 ms
64 bytes from *.*.*.*: icmp_seq=381 ttl=64 time=1.325 ms
64 bytes from *.*.*.*: icmp_seq=382 ttl=64 time=14.232 ms
64 bytes from *.*.*.*: icmp_seq=383 ttl=64 time=1.033 ms
64 bytes from *.*.*.*: icmp_seq=384 ttl=64 time=1.277 ms
64 bytes from *.*.*.*: icmp_seq=385 ttl=64 time=1.157 ms
64 bytes from *.*.*.*: icmp_seq=386 ttl=64 time=1.284 ms
64 bytes from *.*.*.*: icmp_seq=387 ttl=64 time=2.044 ms
64 bytes from *.*.*.*: icmp_seq=388 ttl=64 time=1.894 ms
64 bytes from *.*.*.*: icmp_seq=389 ttl=64 time=1.297 ms
64 bytes from *.*.*.*: icmp_seq=390 ttl=64 time=1.887 ms
64 bytes from *.*.*.*: icmp_seq=391 ttl=64 time=1.302 ms
64 bytes from *.*.*.*: icmp_seq=392 ttl=64 time=1.167 ms
64 bytes from *.*.*.*: icmp_seq=393 ttl=64 time=4.992 ms
64 bytes from *.*.*.*: icmp_seq=394 ttl=64 time=61.175 ms
64 bytes from *.*.*.*: icmp_seq=395 ttl=64 time=99.554 ms
64 bytes from *.*.*.*: icmp_seq=396 ttl=64 time=134.440 ms
64 bytes from *.*.*.*: icmp_seq=397 ttl=64 time=1.349 ms
64 bytes from *.*.*.*: icmp_seq=398 ttl=64 time=1.826 ms
64 bytes from *.*.*.*: icmp_seq=399 ttl=64 time=1.910 ms
64 bytes from *.*.*.*: icmp_seq=400 ttl=64 time=1.198 ms

然后在 wifi.log 中发现如下日志：

Mon Jan 15 21:12:17.501 Scan: <airportd[149]> Snipaste requested a live scan less than 10 seconds after previous request (4.5004s) returning cached scan results

Mon Jan 15 21:12:55.799 Scan: <airportd[149]> Snipaste requested a live scan less than 10 seconds after previous request (4.7355s) returning cached scan results

Mon Jan 15 21:13:11.140 Scan: <airportd[149]> Snipaste requested a live scan less than 10 seconds after previous request (5.0591s) returning cached scan results

Mon Jan 15 21:21:18.139 Info: <airportd[29652]> SCAN request received from pid 387 (Snipaste) with priority 0
Mon Jan 15 21:21:18.406 Driver Event: <airportd[29652]> _bsd_80211_event_callback: SCAN_CACHE_UPDATED (en0)
Mon Jan 15 21:21:18.409 AutoJoin: <airportd[29652]> Successful cache-assisted scan request for Snipaste with channels {(
Mon Jan 15 21:21:18.409     <CWChannel: 0x************> [channelNumber=1(2GHz), channelWidth={20MHz}, active],
Mon Jan 15 21:21:18.409     <CWChannel: 0x************> [channelNumber=2(2GHz), channelWidth={20MHz}, active],
Mon Jan 15 21:21:18.409     <CWChannel: 0x************> [channelNumber=3(2GHz), channelWidth={20MHz}, active],
Mon Jan 15 21:21:18.409     <CWChannel: 0x************> [channelNumber=4(2GHz), channelWidth={20MHz}, active],
Mon Jan 15 21:21:18.409     <CWChannel: 0x************> [channelNumber=5(2GHz), channelWidth={20MHz}, active],
Mon Jan 15 21:21:18.409     <CWChannel: 0x************> [channelNumber=6(2GHz), channelWidth={20MHz}, active]
Mon Jan 15 21:21:18.410 )} took 0.2698 seconds, returned 13 results

Mon Jan 15 21:21:22.251 Info: <airportd[29652]> SCAN request received from pid 387 (Snipaste) with priority 0
Mon Jan 15 21:21:22.251 Scan: <airportd[29652]> Snipaste requested a live scan less than 10 seconds after previous request (4.1119s) returning cached scan results
Mon Jan 15 21:21:32.073 Info: <airportd[29652]> SCAN request received from pid 387 (Snipaste) with priority 0
Mon Jan 15 21:21:32.329 Driver Event: <airportd[29652]> _bsd_80211_event_callback: SCAN_CACHE_UPDATED (en0)
Mon Jan 15 21:21:32.332 AutoJoin: <airportd[29652]> Successful cache-assisted scan request for Snipaste with channels {(
Mon Jan 15 21:21:32.332     <CWChannel: 0x************> [channelNumber=1(2GHz), channelWidth={20MHz}, active],
Mon Jan 15 21:21:32.332     <CWChannel: 0x************> [channelNumber=2(2GHz), channelWidth={20MHz}, active],
Mon Jan 15 21:21:32.332     <CWChannel: 0x************> [channelNumber=3(2GHz), channelWidth={20MHz}, active],
Mon Jan 15 21:21:32.332     <CWChannel: 0x************> [channelNumber=4(2GHz), channelWidth={20MHz}, active],
Mon Jan 15 21:21:32.333     <CWChannel: 0x************> [channelNumber=5(2GHz), channelWidth={20MHz}, active],
Mon Jan 15 21:21:32.333     <CWChannel: 0x************> [channelNumber=6(2GHz), channelWidth={20MHz}, active]
Mon Jan 15 21:21:32.333 )} took 0.2589 seconds, returned 13 results

从日志中来看， Snipaste 每 5 秒钟就会扫描一次 Wi-Fi ，但是因为太频繁，会被系统拦截，直接返回缓存结果。

Mon Jan 15 21:21:22.251 Scan: <airportd[29652]> Snipaste requested a live scan less than 10 seconds after previous request (4.1119s) returning cached scan results

退出 Snipaste 后，到网关的延迟就正常了。

不明白 Snipaste 为什么要扫描 Wi-Fi，扫描到的信息是上传了还是做了别的处理，就没有再具体分析了。
也有可能是用到的某个组件的行为？

Windows 版是否也存在类似现象？

[liulex]

5s 是否是你设置的自动更新的检查间隔？除了检查与下载更新，Snipaste 没有任何联网行为，所用到的组件里只有 SingleApplication 会建立一个 local server 进行监听。

至于检查更新是否会导致你所说的扫描 Wi-Fi，我没有测试过，我目前只有虚拟机环境。不过你在 Snipaste 的选项窗口里关掉启动时检查更新，再重启一下 Snipaste 就可以知道了。

如果扫描行为依然存在，那很大可能就是因为 SingleApplication ，不过它建立的只是本地服务器哦。你可以自行下载编译 SingleApplication 验证一下。

关于你的怀疑，Snipaste 欢迎任何人进行更具体的分析，猜疑就没必要了吧 : )

[sunlei]

自动更新的间隔是默认的 60 秒， 24 小时，我没有调整过。

关闭 检查更新 后，依然会存在同样的现象。

另外，启动 Snipaste 时会出现

Tue Jan 16 00:49:25.659 <airportd[32404]> ERROR: Snipaste (32405) is not entitled for com.apple.wifi.events, but allowing anyways for event type 1

我没有猜疑，也没有任何恶意，只是说一种可能。

[liulex]

谢谢你提供的信息 com.apple.wifi.events，看起来是 Qt 的 bug，一直没修复：
https://bugreports.qt.io/browse/QTBUG-40332
https://bugreports.qt.io/browse/QTBUG-58936
keepassxreboot/keepassxc#306

[liulex]

https://bugreports.qt.io/browse/QTBUG-40332 里提到了一个 workaround，我会在下次更新应用它。

[Meowzz95]

Same issue here, almost called apple support for repairing my NIC LOL