Subnet is returned as 255.255.255.255 instead of 255.255.255.0

[C-Otto]

Environment

System:
    OS: Linux 5.18 Debian GNU/Linux 11 (bullseye) 11 (bullseye)
    CPU: (16) x64 12th Gen Intel(R) Core(TM) i5-12600K
    Memory: 13.71 GB / 31.11 GB
    Shell: 5.1.4 - /bin/bash
  Binaries:
    Node: 16.18.0 - /usr/bin/node
    Yarn: 1.22.17 - /usr/local/bin/yarn
    npm: 8.19.2 - /usr/bin/npm
    Watchman: Not Found
  SDKs:
    Android SDK: Not Found
  IDEs:
    Android Studio: Not Found
  Languages:
    Java: 17.0.4 - /usr/bin/javac
  npmPackages:
    @react-native-community/cli: Not Found
    react: 17.0.2 => 17.0.2 
    react-native: 0.67.4 => 0.67.4 
  npmGlobalPackages:
    *react-native*: Not Found

Platforms

Android 11

Versions

• Android: 11 (8901.4.A.0017.3 release-keys)
• react-native-netinfo: 9.3.4
• react-native: 0.67.4
• react: 17.0.2

Description

On my Android 11 device (Fairphone 3+) running NetInfo.fetch gives correct information, aside from subnet:

[{"details":{"isConnectionExpensive":false,"txLinkSpeed":57,"rxLinkSpeed":-1,"linkSpeed":57,"subnet":"255.255.255.255","ipAddress":"10.0.0.133","frequency":2462,"strength":72,"bssid":"xxx","ssid":"xxx"},"isConnected":true,"type":"wifi","isInternetReachable":true,"isWifiEnabled":true}]

The correct network information would be 10.0.0.133/24, i.e. a subnet of 255.255.255.0. On my desktop machine (in the same network) I see

inet 10.0.0.2/24 brd 10.0.0.255 scope global dynamic noprefixroute eno1
       valid_lft 860383sec preferred_lft 860383sec

When checking the network details manully (long-pressing on the Wifi icon) I also get a subnet mask of 255.255.255.0.

[C-Otto]

Same issue with 9.3.5, react-native 0.68.4.

[mikehardy]

Very odd - haven't seen this before - next step will be do instrument the java code where we pull the info from the device and see what the system APIs are returning, then dig in from there. Curious for results 🤔

[C-Otto]

I added some debug code:

String debug = String.format("%s %s %s %d", netAddress, netAddress.getInterfaceAddresses(), netAddress.getInterfaceAddresses().get(1), netAddress.getInterfaceAddresses().get(1).getNetworkPrefixLength());

This gives:

name:wlan0 (wlan0) [/fe80::e0d0:cfff:fe98:54f4%wlan0/64 [null], /2a0a:a540:4ee9:0:e0d0:cfff:fe98:54f4/64 [null], /2a0a:a540:4ee9:0:5cbd:e442:6b8c:e03/64 [null], /10.0.0.133/24 [/10.0.0.255]] /2a0a:a540:4ee9:0:e0d0:cfff:fe98:54f4/64 [null] 64]]

I guess your code doesn't like IPv6?

[mikehardy]

I guess your code doesn't like IPv6?

It's open source, it's your code 😆

If there's something that needs to change I'm open to any+all reasonable PRs

This module existed long before I had heard of react-native, and it'll be here long after I've stopped hitting the "merge" button, I imagine you are correct and it's just IPv4-only at the moment, or incorrectly-IPv6

[mikehardy]

You win the internet points for the day for nailing this with what appears to be a squeaky clean PR. Chapeau

[matt-oakes]

🎉 This issue has been resolved in version 9.3.6 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot 📦🚀