[FS#1252] No IP Assigned to Interface with QMI on Quectel EC-25A

[LEDE Bugs]

A new Flyspray task has been opened.  Details are below. 

User who did this - John Marrett (johnfzc) 

Attached to Project - LEDE Project
Summary - No IP Assigned to Interface with QMI on Quectel EC-25A
Task Type - Bug Report
Category - Base system
Status - Unconfirmed
Assigned To - 
Operating System - All
Severity - Low
Priority - Very Low
Reported Version - Trunk
Due in Version - Undecided
Due Date - Undecided
Details - I'm attempting to use QMI on a GL.Inet MiFi equipped with a Quectel EC-25A cellular modem.

When I configure the interface using qmi I am able to connect to the cellular network at the radio layer, however my wwan0 interface is not assigned an IP address. Here's my configuration from /etc/config/network:

    config interface 'modem'
            option proto 'qmi'
            option ifname 'wwan0'
            option device '/dev/cdc-wdm0'
            option country 'country11'
            option apn 'inet.bell.ca'

And some commands showing the device behaviour. You'll note that raw_ip needs to be set to Y. I've integrated this [patch](https://github.com/bmork/LEDE/commit/10aed12fa587e818e4dc5d0db54545623fbe9b5f) to have qmi.sh set the raw_ip mode when required. 

    root at OpenWrt:~# cat /sys/class/net/wwan0/qmi/raw_ip
    Y
    root at OpenWrt:~# ifup modem
    root at OpenWrt:~# uqmi -d /dev/cdc-wdm0 --get-data-status
    "connected"
    root at OpenWrt:~# uqmi -d /dev/cdc-wdm0 --get-current-settings
    {
        "pdp-type": "ipv4",
        "ip-family": "ipv4",
        "mtu": 1500,
        "ipv4": {
            "ip": "100.105.180.51",
            "dns1": "206.47.201.246",
            "dns2": "207.231.231.254",
            "gateway": "100.105.180.52",
            "subnet": "255.255.255.248"
        },
        "ipv6": {
            
        },
        "domain-names": {
            
        }
    }
    root at OpenWrt:~# ifconfig wwan0
    wwan0     Link encap:UNSPEC  HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00  
              inet6 addr: fe80::d789:480e:bfc8:2dac/64 Scope:Link
              UP POINTOPOINT RUNNING NOARP MULTICAST  MTU:1500  Metric:1
              RX packets:28 errors:0 dropped:0 overruns:0 frame:0
              TX packets:8 errors:0 dropped:0 overruns:0 carrier:0
              collisions:0 txqueuelen:1000 
              RX bytes:5129 (5.0 KiB)  TX bytes:768 (768.0 B)

If I manually use the uqmi command to connect to the cellular network I can then drive the wwan0 interface using dhcp successfully. Here's my /etc/config/network.

    config interface 'modem'
            option proto 'dhcp'
            option ifname 'wwan0'

And the resulting successful network connection:

    root at OpenWrt:~# ifup modem
    root at OpenWrt:~# ifconfig wwan0
    wwan0     Link encap:UNSPEC  HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00  
              inet addr:100.105.180.51  P-t-P:100.105.180.51  Mask:255.255.255.248
              inet6 addr: fe80::d789:480e:bfc8:2dac/64 Scope:Link
              UP POINTOPOINT RUNNING NOARP MULTICAST  MTU:1500  Metric:1
              RX packets:80 errors:0 dropped:0 overruns:0 frame:0
              TX packets:68 errors:0 dropped:0 overruns:0 carrier:0
              collisions:0 txqueuelen:1000 
              RX bytes:24102 (23.5 KiB)  TX bytes:16842 (16.4 KiB)

    root at OpenWrt:~# ping -c 1 google.ca
    PING google.ca (172.217.1.163): 56 data bytes
    64 bytes from 172.217.1.163: seq=0 ttl=51 time=29.792 ms

    --- google.ca ping statistics ---
    1 packets transmitted, 1 packets received, 0% packet loss
    round-trip min/avg/max = 29.792/29.792/29.792 ms

I believe that for some reason the dhcp client isn't being run on the wwan0 interface by qmi.sh once it's online but I'm not able to determine how this is supposed to work. I'm eager to address this issue and submit the resulting patches. Please let me know if you can help.

    root at OpenWrt:~# ping -c 1 8.8.8.8
    PING 8.8.8.8 (8.8.8.8): 56 data bytes
    64 bytes from 8.8.8.8: seq=0 ttl=54 time=31.805 ms

    --- 8.8.8.8 ping statistics ---
    1 packets transmitted, 1 packets received, 0% packet loss
    round-trip min/avg/max = 31.805/31.805/31.805 ms


More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=1252