[LEDE-DEV] enhanced 3G support

[Giuseppe Lippolis]

Dear All,
I currently add supprt for the dwr-512 device on LEDE.
This device have a 3G modem embedded.
The current available configuration uses the usb-option to establish the 3G
connection over ppp.
Nevertheless the modem offer one cdc-ether interface with better
performance.

T:  Bus=01 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#=  2 Spd=480  MxCh= 0
D:  Ver= 2.00 Cls=02(comm.) Sub=00 Prot=00 MxPS=64 #Cfgs=  1
P:  Vendor=2001 ProdID=7d04 Rev= 3.00
S:  Manufacturer=D-Link,Inc
S:  Product=D-Link DWM-158
C:* #Ifs= 7 Cfg#= 1 Atr=a0 MxPwr=500mA
A:  FirstIf#= 0 IfCount= 2 Cls=02(comm.) Sub=06 Prot=00
I:* If#= 0 Alt= 0 #EPs= 1 Cls=02(comm.) Sub=06 Prot=00 Driver=cdc_ether
E:  Ad=88(I) Atr=03(Int.) MxPS=  64 Ivl=125us
I:  If#= 1 Alt= 0 #EPs= 0 Cls=0a(data ) Sub=00 Prot=00 Driver=cdc_ether
I:* If#= 1 Alt= 1 #EPs= 2 Cls=0a(data ) Sub=00 Prot=00 Driver=cdc_ether
E:  Ad=81(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms
E:  Ad=01(O) Atr=02(Bulk) MxPS= 512 Ivl=0ms
I:* If#= 2 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=02 Prot=01 Driver=option
E:  Ad=87(I) Atr=03(Int.) MxPS=  64 Ivl=125us
E:  Ad=82(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms
E:  Ad=02(O) Atr=02(Bulk) MxPS= 512 Ivl=0ms
I:* If#= 3 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=00 Prot=00 Driver=option
E:  Ad=83(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms
E:  Ad=03(O) Atr=02(Bulk) MxPS= 512 Ivl=0ms
I:* If#= 4 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=00 Prot=00 Driver=option
E:  Ad=84(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms
E:  Ad=04(O) Atr=02(Bulk) MxPS= 512 Ivl=0ms
I:* If#= 5 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=00 Prot=00 Driver=option
E:  Ad=85(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms
E:  Ad=05(O) Atr=02(Bulk) MxPS= 512 Ivl=0ms
I:* If#= 6 Alt= 0 #EPs= 2 Cls=08(stor.) Sub=06 Prot=50 Driver=(none)
E:  Ad=86(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms
E:  Ad=06(O) Atr=02(Bulk) MxPS= 512 Ivl=0ms

It seems to me that currently this kind of "protocol" is not supported in
LEDE.
In particular I'm unable to found an interface type in the
/etc/config/network to setup this kind of connection.

Currently I'm able to establish a connection setting the interface in
"manual" mode.

To do this I setup an usb interface

config interface 'wan3g'
        option ifname 'usb0'
        option proto 'dhcp'

then I need to send manually the following command to the /dev/ttyUSB0 to
establish the 3G connection:

	AT+CFUN=1
	AT+CPIN="<SIM PIN>"
 	AT+CREG?
		> +CREG: 2,1,"1CE3","0BCA3360",6 (6=UTRAN w/HSDPA and HSUPA)
	AT+CGDCONT=1,"IP","<APN>",0,0
	AT+CGACT=1,1
	AT+CGACT?
	AT+CGPADDR=1
		>> +CGPADDR: 1, "109.42.15.170"
	AT+CGPRCO?
		>> +CGPRCO: 1, "139.7.30.126", "139.7.30.125", "", ""
	AT+CGDATA="M-MBIM",1,1

at this point the IF is UP and working:
usb0      Link encap:Ethernet  HWaddr 02:00:FF:AA:AA:AA
          inet addr:109.42.15.170  Bcast:109.42.15.171  Mask:255.255.255.252
          inet6 addr: fe80::ffff:feaa:aaaa/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:314 errors:0 dropped:0 overruns:0 frame:0
          TX packets:360 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:29855 (29.1 KiB)  TX bytes:33129 (32.3 KiB)

		  
Can someoune help me in introduce the handling of this "protocol" in LEDE?

Thanks,
Bye.