UDP fallback doesn't work with gfwlist or custom rules

[AaronChen0]

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Describe the bug When browsing instagram or youtube with bypass-lan-china route, I can see quic/udp traffic for http3 in tcpdump from my server. But there is only tcp traffic when choosing gfwlist or custom rules and udp fallback.

To Reproduce Steps to reproduce: (Testing with or without plugin is the same for this bug)

1. Enable udp-fallback with gfwlist route or custom rules (can confirm the related domains are in the route rules).
2. Using the following command to observe udp traffic in your udp fallback server.

   tcpdump port 31555 and udp

3. Browsing youtube in a chrome browser. Can view youtube normally.
4. See no udp traffic from step 2. Switching to bypass-lan-china route, I can observe udp traffic.

Expected behavior When using custom rules, I can view youtube via http3/quic/udp.

Screenshots See above. I can add more if requested.

Smartphone (please complete the following information):

• Android/Chrome OS version: MIUI 13.0.1 / Android 12
• Device: Redmi 10X 4G
• Version: V5.3.3
• Last version that did not exhibit the issue: [not applicable]

Configuration Put an x inside the [ ] that applies.

• [x] IPv4 server address
• [ ] IPv6 server address
• [x] Client IPv4 availability
• [ ] Client IPv6 availability
• Encrypt method: AES-GCM-256
• Route
  • [ ] All
  • [ ] Bypass LAN
  • [ ] Bypass China
  • [ ] Bypass LAN & China
  • [x] GFW List
  • [ ] China List
  • [ ] Custom rules
• [ ] IPv6 route
• [ ] Apps VPN mode
  • [ ] Bypass mode
• Remote DNS: dns.google
• [ ] DNS over UDP
• Plugin configuration (if applicable): v2ray-plugin+websocket
• [ ] Auto Connect
• [ ] TCP Fast Open
• If you're not using VPN mode, please supply more details here:

Additional context Add any other context about the problem here.

[AaronChen0]

Hi, @Mygod . Can you reproduce this issue? Do you have any clues? I can reproduce this issue with the lastest commit.

[Mygod]

Feel free to PR. :)