Re: [RFC PATCH v3] gprs: add function to handle activated context

[Arun Ravindran <ext-arun.1.ravindran@nokia.com>]

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Hi Redouane,

> The purpose of the patch is to handle Network Initiated Context 
> Activation and PDN connection request as part of EPS Attach procedure 
> (LTE) in oFono core.
>
> In order to avoid issue regarding CID allocation :
> - driver should call the core using ofono_gprs_set_cid_range function 
> to specify CID range for UE initiated PDN connection
> - driver could use a new function to check if the CID is already used 
> or not : ofono_gprs_is_cid_used, usefull in case the modem is not 
> using a specific range for UE initiated PDN connection.
> - driver will use a new function to notify the gprs atom of a new PDN 
> connection with all the ip parameters from AT+CGCONTRDP (I can provide 
> an update later to handle PCSCF and IMS Signaling Flag as well) 
> commmand : ofono_gprs_context_activated
>
27.007 section 10.1.1 says

Defined values
<cid>: a numeric parameter which specifies a particular PDP context 
definition. The parameter is local to the TE-
MT interface and is used in other PDP context-related commands. The 
range of permitted values (minimum
value = 1) is returned by the test form of the command.
NOTE 1: The <cid>s for network-initiated PDP contexts will have values 
outside the ranges indicated for the
<cid> in the test form of the commands +CGDCONT and +CGDSCONT.

According to this, the cid of user initiated context and network 
initiated context doesn't overlap.

Also

+CGEV: ME PDN ACT <cid>[,<reason>[,<cid_other>]]
The mobile termination has activated a context. The context represents a 
PDN connection in LTE or a Primary
PDP context in GSM/UMTS. The <cid> for this context is provided to the 
TE. This event is sent either in result
of explicit context activation request (+CGACT), or in result of 
implicit context activation request associated to
attach request (+CGATT=1). The format of the parameters <cid>, 
<cid_other> are found in command
+CGDCONT.

We should also be able to get the cid of the default context, from CGEV 
indications.

> ofono_gprs_context_activated is similar to 
> ofono_gprs_context_deactivated.
> This function must be call by any gprs driver when :
>  - a context has been activated without explicit request as part of 
> attach procedure in LTE (PDN ACT X and X is a unused CID)
>  - a context has been activated by the Network (NW PDN ACT X, NW ACT X,Y)
>
> Behavior of the function :
>
> List all the context and try to find correct APN with empty username 
> and empty password.
> If such context is not found then create a new one with "Internet" 
> type only if we are in LTE with no Active context.
> Otherwise deactivate the connection.
>
> For the context (found or created):
>     Update the settings
>     Set to active
>
> The function will also assign the context to a context driver.

Please correct me if i miss some information.

Regards
Arun