GCC have not been capable enough to catch some linker errors which arose when
ethernet support for LWIP was disabled. Checks have been added to make sure that
unrefrenced code is not linked in.
nsapi_ppp glue layer is made more transparent to public cellular API. Storage of IP
addresses is removed. PPP layer already stores the addresses, so we pass the pointer back
to the upper layers.
If PPP is not used, we provide dummy functions.
* state machine corrections
* adding various standard API methods
* Addition/revision/enhancement of the nsapi_ppp glue layer
* Turning off debug by default
Mainly reutilizing code from ublox C027 support lib.
As we are using external PDP context, i.e., an external IP stack,
we will pass username and password to underlying stack running PPP.
We only support CHAP as the authentication protocol.
In case of carrier lost, we would like to inform PPP data pump.
That involved setting up link status flag down semaphores.
mbed_lwip_bringup() and mbed_lwip_bringdown() had been Ethernet specific only.
We extend these routines to support PPP as well. Currently we support only one interface
at a time. However, future enhancement to multi interface support should be trivial.
Martin Kojtal
Teemu Kultala
Mika Leppänen
Jimmy Brisson
Hasnain Virk
Kevin Bracey