Note: some modifications have been done to the UE too, but for syntactic
reasons. The UE may fail to work, not tested.

For the UE, we have the problem of handling properly SecurityModeCommand.
We don't verify its integrity. This is a bit complicated to handle properly
and may require some API changes in the PDCP layer. So, as of today, the
integrity of this message is not verified.

Also, NSA mode has been touched, but it should not be a problem. But not
tested, so not sure.

Signed-off-by: Raphael Defosseux <raphael.defosseux@eurecom.fr>

add DLinformationTransfer in nrUE, process SRB!=1 in UE (instead of discard), change struct member pdusession into pduSession to increase code readability (another struct contains also pdusession in lower case)

-If the gNB crashes when the X2 connection is established with the eNB, an sctp shutdown event is received from the eNB. However the x2 data related with
the connection were not removed from the RB tree. Then if the gNB tried to reconnect, it made the eNB exit because the eNB had kept the previous data.
Now we remove the x2 data as soon as the sctp shutdown event is received so that the eNB does not exit anymore at the next connection attempts.

This reverts commit 7011c0d9

This reverts commit 3585d7da

This reverts commit 4100dc33

This reverts commit 64aa42d6

Enable IP TUN interface configuration upon reception of PDU Session Establishment Accept NAS message

-User plane traffic validation with OAI UE and OAI CN:

-Downlink ping initiated from the CN is received at the IP interface of the UE. However it seems that there is some packet corruption preventing the generaration of ping reply.

-Uplink ping initiated from the UE reaches the OAI CN machine. However no ping reply is seen yet either.

-Apply patch from Fujitsu
-Trigger dedicated RRC Reconfiguration with DRB and SRB2 configuration once the PDU session is established
-Validation of control plane sequence with OAI CN and Nokia SA Box