Should not add ipv6 route if ipv6 address didn't be set

Operating system

Android

System version

Android 13

Installation type

Original sing-box Command Line

If you are using a graphical client, please provide the version of the client.

1.9.0-rc.1

Version

No response

Description

If user didn't specify ipv6 address for tun interface, auto route should not add route for it.

https://github.com/SagerNet/sing-box-for-android/blob/1a7b9dc6fd2e73337853b20397b8504e1daf874e/app/src/main/java/io/nekohasekai/sfa/bg/VPNService.kt#L90-L97

Reproduction

"inbounds": [
    {
      "auto_route": true,
      "interface_name": "singbox",
      "inet4_address": "172.119.0.1/30",
      "type": "tun",
      "strict_route": true,
      "stack": "gvisor",
      "sniff": true
    }
  ],

Logs

No response

Supporter

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Integrity requirements

• I confirm that I have read the documentation, understand the meaning of all the configuration items I wrote, and did not pile up seemingly useful options or default values.
• I confirm that I have provided the server and client configuration files and process that can be reproduced locally, instead of a complicated client configuration file that has been stripped of sensitive data.
• I confirm that I have provided the simplest configuration that can be used to reproduce the error I reported, instead of depending on remote servers, TUN, graphical interface clients, or other closed-source software.
• I confirm that I have provided the complete configuration files and logs, rather than just providing parts I think are useful out of confidence in my own intelligence.

Start with app/src/main/java/io/nekohasekai/sfa/bg/VPNService.kt around lines 90-97, then reproduce the issue with the minimal TUN configuration in the report. Done means auto_route does not add an IPv6 route when no IPv6 address is configured; verify the route behavior on Android 13.