Quectel UC20: Correct way to get it up and running on embedded?
Einar Jón
tolvupostur at gmail.com
Mon Mar 20 11:14:37 UTC 2017
Hello,
We have an Quectel UC20 modem running with ModemManager. We are using
the libmm python module (gi.repository.ModemManager) and no
NetworkManager.
This will be in hundreds of unattended embedded boxes, and losing the
connection will require a site visit in many cases.
I have wwan0 set as dhcp, and dhclient is started automatically on "ifup wwan0".
This kind of fits with what was said here:
https://lists.freedesktop.org/archives/modemmanager-devel/2015-December/002419.html
but much of the implementation has been guesswork and trial&error...
Our main issues:
Operstate seems to be always UNKNOWN
"ip link set dev wwan0 up" and "ip link set dev wwan0 down" seem to do nothing.
We need to reset the connection once a day (with mmcli --disable),
because of external reasons.
This mostly works, but sometimes we lose connectivity after the reconnect.
In those cases I have 2 IP addresses in the interface, and ip route
tells me that both of them are gateways.
"ifup wwan0 && ifdown wwan0" fixes the connection again without any
action from the python script (this automatically starts a new
dhclient and updates ip route).
This seems to be just a timing issue, or a question of doing things in
the right order.
My main questions:
1) what do I need to do to have a reliable connection?
2) when do I need to do those things?
- in what state should I call ifup ?
- in what state should I call connect_bearer()? Any exceptions?
3) I switch modem states really fast (from DISABLING to CONNECTING in
under a second - see syslog below). Do some of these states need to
wait a bit?
4) Is ModemManager 1.4.10 too old? Are there any major improvements
I'm missing from staying on Ubuntu 12.04?
NOTE: To find out the status of the connection, I check if the IfState
is up or down (basically "grep wwan0 /run/network/ifstate"), instead
of checking operstate (which is UNKNOWN no matter what I do).
If ifstate is down I call "ifup wwan0" manually.
When disconnecting (and on the pyhon startup), I call "ifdown wwan0" manually.
Relevant python code:
def handle_modem_state(self, oldState, state):
logging.debug('Handle modem state, old: ' +
self.modem_state_str(oldState) + ' new: ' +
self.modem_state_str(state))
if state == ModemManager.ModemState.DISABLED:
self.enable_modem() # calls modemProxy.Enable(1, ...)
elif state == ModemManager.ModemState.ENABLED:
self.register_modem() # calls modemProxy.Register(...)
elif state == ModemManager.ModemState.SEARCHING:
pass
elif state == ModemManager.ModemState.REGISTERED:
if oldState != ModemManager.ModemState.CONNECTING and oldState
!= ModemManager.ModemState.DISCONNECTING:
self.connect_bearer() # get bearer from DBUS and connect
elif state == ModemManager.ModemState.CONNECTED:
self.triedPreferredOperator = False
elif state == ModemManager.ModemState.CONNECTING:
if not self.is_network_interface_up('wwan0'): # check operstate/ifstate
self.set_network_state('wwan0', 'up') # calls ifup
wwan0 in a new process
elif state == ModemManager.ModemState.DISABLING:
if self.is_network_interface_up('wwan0'): # check operstate/ifstate
self.set_network_state('wwan0', 'down') # calls ifdown
wwan0 in a new process
result of: ip -4 a show dev wwan0 | grep -v forever
4: wwan0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast
state UNKNOWN qlen 1000
inet XX.YY.197.125/30 brd XX.YY.197.127 scope global wwan0
inet XX.YY.80.188/30 brd XX.YY.80.191 scope global wwan0
/var/log/syslog with minor obfuscation - python script is "modemmonitor[1475]"
# connection working before modem-reset
Mar 19 06:35:51 ubuntu12 modem-reset: Performing daily modem reset:
'mmcli --disable --modem=0'
Mar 19 06:35:51 ubuntu12 my_tunnel[3352]: AutoSSH2 stop
Mar 19 06:35:51 ubuntu12 autossh[14671]: received signal to exit (15)
Mar 19 06:35:51 ubuntu12 my_tunnel[3352]: AutoSSH2 stop: done
Mar 19 06:35:52 ubuntu12 modemmonitor[1475]: Modem state: CONNECTED -> DISABLING
Mar 19 06:35:52 ubuntu12 nslcd[1530]: [65b848] <passwd="*"> "*": name
denied by validnames option
Mar 19 06:35:52 ubuntu12 nslcd[1530]: [725ebb] <passwd="*"> "*": name
denied by validnames option
Mar 19 06:35:52 ubuntu12 my_tunnel[3396]: AutoSSH2 stop
Mar 19 06:35:52 ubuntu12 my_tunnel[3396]: AutoSSH2 not running
Mar 19 06:35:52 ubuntu12 my_tunnel[3396]: AutoSSH2 stop: done
Mar 19 06:35:52 ubuntu12 modemmonitor[1475]: ifdown wwan0 (for
dchlient/ssh) returned my_tunnel[3396]: AutoSSH2
stop#012my_tunnel[3396]: AutoSSH2 not running#012my_tunnel[3396]:
AutoSSH2 stop: done
Mar 19 06:35:52 ubuntu12 modemmonitor[1475]: Operator Code:
Mar 19 06:35:52 ubuntu12 modemmonitor[1475]: Operator Name:
Mar 19 06:35:52 ubuntu12 modemmonitor[1475]: Registration State: UNKNOWN
Mar 19 06:35:52 ubuntu12 modemmonitor[1475]: Modem state: DISABLING -> DISABLED
Mar 19 06:35:52 ubuntu12 modemmonitor[1475]: Enabling modem...
Mar 19 06:35:52 ubuntu12 modemmonitor[1475]: Modem state: DISABLED -> ENABLING
Mar 19 06:35:52 ubuntu12 modemmonitor[1475]: Operator Code: 20404
Mar 19 06:35:52 ubuntu12 modemmonitor[1475]: Operator Name: DATA ONLY
Mar 19 06:35:52 ubuntu12 modemmonitor[1475]: Registration State: HOME
Mar 19 06:35:52 ubuntu12 modemmonitor[1475]: Modem state: ENABLING -> REGISTERED
Mar 19 06:35:52 ubuntu12 modemmonitor[1475]: Current operator: 20404
Mar 19 06:35:52 ubuntu12 modemmonitor[1475]: Modem state: REGISTERED
-> CONNECTING
Mar 19 06:35:53 ubuntu12 dhclient: DHCPDISCOVER on wwan0 to
255.255.255.255 port 67 interval 60
Mar 19 06:35:54 ubuntu12 nslcd[1530]: [87a0be] <passwd=-1>
ldap_start_tls_s() failed: Can't contact LDAP server: Transport
endpoint is not connected (uri="ldap://ssh.example.com:389")
Mar 19 06:35:54 ubuntu12 nslcd[1530]: [87a0be] <passwd=-1> failed to
bind to LDAP server ldap://ssh.example.com:389: Can't contact LDAP
server: Transport endpoint is not connected
Mar 19 06:35:54 ubuntu12 nslcd[1530]: [87a0be] <passwd=-1> no
available LDAP server found: Can't contact LDAP server
Mar 19 06:35:54 ubuntu12 logger: Unloading CAN driver
Mar 19 06:35:54 ubuntu12 nslcd[1530]: [8e8cbc] <passwd="*"> "*": name
denied by validnames option
Mar 19 06:35:54 ubuntu12 nslcd[1530]: [91daaa] <passwd=-1> no
available LDAP server found: Server is unavailable
Mar 19 06:35:54 ubuntu12 logger: Loading CAN driver
Mar 19 06:35:54 ubuntu12 kernel: [410151.671069] pch_can 0000:02:0c.3:
irq 51 for MSI/MSI-X
Mar 19 06:35:54 ubuntu12 kernel: [410151.671121] pch_can 0000:02:0c.3
(unregistered net_device): PCH CAN opened with MSI
Mar 19 06:35:54 ubuntu12 nslcd[1530]: [66d378] <passwd="*"> "*": name
denied by validnames option
Mar 19 06:36:07 ubuntu12 ntpdate[3606]: adjust time server
46.243.26.34 offset 0.000085 sec
Mar 19 06:36:11 ubuntu12 acpid: client 2632[0:0] has disconnected
Mar 19 06:36:11 ubuntu12 acpid: client connected from 3986[0:0]
Mar 19 06:36:11 ubuntu12 acpid: 1 client rule loaded
Mar 19 06:36:53 ubuntu12 dhclient: DHCPDISCOVER on wwan0 to
255.255.255.255 port 67 interval 1
Mar 19 06:36:53 ubuntu12 dhclient: DHCPREQUEST of XX.YY.197.125 on
wwan0 to 255.255.255.255 port 67
Mar 19 06:36:53 ubuntu12 dhclient: DHCPOFFER of XX.YY.197.125 from XX.YY.197.126
Mar 19 06:36:53 ubuntu12 dhclient: DHCPACK of XX.YY.197.125 from XX.YY.197.126
Mar 19 06:36:53 ubuntu12 nslcd[1530]: [29fdc1] <passwd="*"> "*": name
denied by validnames option
Mar 19 06:36:54 ubuntu12 dhclient: bound to XX.YY.197.125 -- renewal
in 2886 seconds.
Mar 19 06:36:54 ubuntu12 my_tunnel[4118]: AutoSSH2 start
Mar 19 06:37:04 ubuntu12 nslcd[1530]: [802c05] <passwd=-1>
ldap_start_tls_s() failed: Can't contact LDAP server: Connection timed
out (uri="ldap://ssh.example.com:389")
Mar 19 06:37:04 ubuntu12 nslcd[1530]: [802c05] <passwd=-1> failed to
bind to LDAP server ldap://ssh.example.com:389: Can't contact LDAP
server: Connection timed out
Mar 19 06:37:04 ubuntu12 nslcd[1530]: [802c05] <passwd=-1> no
available LDAP server found: Can't contact LDAP server
Mar 19 06:37:04 ubuntu12 autossh[4150]: port set to 0, monitoring disabled
Mar 19 06:37:04 ubuntu12 autossh[4151]: starting ssh (count 1)
Mar 19 06:37:04 ubuntu12 autossh[4151]: ssh child pid is 4152
Mar 19 06:37:04 ubuntu12 my_tunnel[4118]: AutoSSH2 start: done
Mar 19 06:37:04 ubuntu12 nslcd[1530]: [2a1dc5] <passwd="*"> "*": name
denied by validnames option
Mar 19 06:37:16 ubuntu12 ntpdate[4201]: no server suitable for
synchronization found
Mar 19 06:37:16 ubuntu12 modemmonitor[1475]: ifup wwan0 (for
dchlient/ssh) returned my_tunnel[4118]: AutoSSH2
start#012my_tunnel[4118]: AutoSSH2 start: done#012ssh
stop/waiting#012ssh start/running, process 4209
Mar 19 06:37:17 ubuntu12 modemmonitor[1475]: Modem state: CONNECTING
-> CONNECTED
Mar 19 06:39:11 ubuntu12 /usr/bin/ssh[4152]: error: ssh: connect to
host ssh.example.com port 22: Connection timed out
Mar 19 06:39:11 ubuntu12 autossh[4151]: ssh exited with error status
255; restarting ssh
Mar 19 06:39:11 ubuntu12 autossh[4151]: starting ssh (count 2)
Mar 19 06:39:11 ubuntu12 autossh[4151]: ssh child pid is 4492
# connection broken from now on
---- Hardware/software
Ubuntu 12.04 with kernel 3.13.0-57-generic
CPU : Intel(R) Atom(TM) CPU E680 @ 1.60GHz
using qmi_wwan, cdc_wdm kernel modules
ModemManager 1.4.10
----
$ mmcli -m 0
/org/freedesktop/ModemManager1/Modem/0 (device id '4dd8d723ec[...]')
-------------------------
Hardware | manufacturer: 'QUALCOMM INCORPORATED'
| model: '0'
| revision: 'UC20GQBR03A10E1G 1 [2014/05/05 9:00:00]'
| supported: 'gsm-umts'
| current: 'gsm-umts'
| equipment id: '861075023803802'
Best regards
Einar Jón Gunnarsson
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