Bug: data mobile interface looses ip

[pparent]

I'm wondering about something, as this problem is an IP loss problem, I think it should be noted that by defualt NetworkManager uses it's internal dhcp handler. But it is also possible to configure it to use dhclient. And I wonder if the later would not be more reliable.

So I think I will test to change the configuration of my NetworkManager to use dhclient, and see if it has any impact on this bug.

[domubpkm]

Any news about this annoying issue ?

[pparent]

@domubpkm

I will soon try to write a workaround script, but when I have time.

[domubpkm]

@pparent THANKS. I still linked this post to NotKit from the Volla team. This is still a big problem for the Volla 22 which will have to be fixed. In addition, network loss is almost systematic each time the volla 22 is restarted.

[pparent]

@domubpkm

I've written a workaround script that I'm currently testing, that detects an IP loss on the interface and automatically reinitialize the modem when it happens. For now it seems to work quite well, and even seems to have a positive impact on VoLTE connexion. I will test it for a few days, and if everything goes well, I will publish it here.

[domubpkm]

@pparent Great.
A good test is to see if the connection is still lost after reboot or complete shutdown and startup.

[pparent]

@domubpkm said:

A good test is to see if the connection is still lost after reboot or complete shutdown and startup.

This is not really the purpose of the script for now. The purpose of the script is that, when you keep the phone up, and you travel, Internet remain accessible at any moment, without needing to manualy go in the settings to restart the connection.

[domubpkm]

@pparent ok. Thanks for the clarification. I just said that because it is a behavior i noticed very frequently.

[gpatel-fr]

@pparent

For the record I never commented on this problem because I had not yet seen it but I recently observed something that looked like it: I did pass in an area without cellular support and when going back to civilization, the cellular data did come back but no routing it seems, as you describe.
I'd need a Faraday cage to confirm.

[pparent]

Here is the script that I currently use, it improves greatly the usability of my phone, because it reduces dramatically the need to go in the settings in order to get access to the Internet.

Though it's not perfect and might have secondary effects, use at your own risks!

#!/bin/bash

MODEM="/ril_0"
HOST_TO_PING="8.8.8.8 www.google.com ubports.com 1.1.1.1 9.9.9.9 cloudflare.com amazon.com microsoft.com wikipedia.org apple.com"

function get_modem_iface()
{
/usr/share/ofono/scripts/list-contexts |awk -v target="$1" '
/^\[ \/ril_/ { r=$2 }

/Type = internet/ { i=1 }

/Interface=ccmni/ && r==target && i {
    sub(/^.*Interface=/, "")
    sub(/ .*/, "")
    print
    exit
}
'
}

IFACE=$(get_modem_iface $MODEM)

i=0;

while true; do
    if [ "$IFACE" = "" ]; then
        IFACE=$(get_modem_iface $MODEM)
    fi
    ifconfig $IFACE | grep -v inet6 | grep inet > /dev/null 2>&1
    if [ "$?" -ne "0" ]; then
        gdbus call --system --dest org.ofono --object-path "$MODEM" --method org.ofono.NetworkRegistration.GetProperties | grep "'Technology': <'lte'>" > /dev/null 2>&1
        if [ "$?" -eq "0" ]; then
            date
            echo "IFACE: $IFACE";
            echo "IP loss detected"
            /usr/share/ofono/scripts/offline-modem $MODEM
            /usr/share/ofono/scripts/online-modem $MODEM
            sleep 5;
            IFACE=$(get_modem_iface $MODEM)
        fi
    else
        route=$(ip route show default)
        if [ "$route" = "" ]; then 
            gdbus call --system --dest org.ofono --object-path "$MODEM" --method org.ofono.NetworkRegistration.GetProperties | grep "'Technology': <'lte'>" > /dev/null 2>&1
            if [ "$?" -eq "0" ]; then
                date
                echo "IFACE: $IFACE";
                echo "Route loss detected"
                /usr/share/ofono/scripts/offline-modem $MODEM
                /usr/share/ofono/scripts/online-modem $MODEM
                sleep 5;
                IFACE=$(get_modem_iface $MODEM)
            fi
        fi
    fi
    
    i=$((i+1))
    if [ "$i" -gt "15" ]; then
        i=0;
        gdbus call --system --dest org.ofono --object-path "$MODEM" --method org.ofono.NetworkRegistration.GetProperties | grep "'Technology': <'lte'>" > /dev/null 2>&1
        if [ "$?" -eq "0" ]; then
            internetaccess=0;
            for host in $HOST_TO_PING ; do
                ping -W 1 -c 1 $host >/dev/null 2>&1
                if [ "$?" -eq "0" ]; then
                    internetaccess=1;
                    break;
                else
                    echo "Ping to $host failed, trying next one in 4s ...."
                    sleep 4;
                fi
            done
            if [ "$internetaccess" -eq "0" ]; then
                    date
                    echo "IFACE: $IFACE";
                    echo "Internet access loss detected"
                    /usr/share/ofono/scripts/offline-modem $MODEM
                    /usr/share/ofono/scripts/online-modem $MODEM
                    sleep 5;
                    IFACE=$(get_modem_iface $MODEM)
            fi
        fi
    fi
    sleep 20;
done