Make the link local negotiation for IPV6 in PPP optional and
configurable.
This is because some modems do not support the IPV6 negotiation and
sending IPV6CP frames would in some cases break the network
configuration phase, resulting in a timeout during the Phase Network.
Please note that this does not disable the IPV6 support for the outgoing
communication (IPV6 is still enabled even if this option is not
selected) but just for the local link between lwIP and modem.
Signed-off-by: Francesco Giancane <francesco.giancane@accenture.com>
Merges https://github.com/espressif/esp-idf/pull/4782
Closes https://github.com/espressif/esp-idf/issues/1065
LwIP has support for IP_PKTINFO, but it cannot be activated as it is
not configurable. This fix adds in the ability to configure it.
Merges https://github.com/espressif/esp-idf/pull/3983
1. add support for ESP32 DTE
2. add support for SIM800/BG96 DCE
3. add PPPoS setup procedure
4. add support for SMS
5. add mqtt example after PPP connection established