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

For whatever reason we need N_TA_offset to be 0 for the basic simulator
to function properly.

This is more a hack than a proper solution. More analysis is needed
to understand what happens and what should be really done.

In TDD mode the eNB does not output data all the time,
only in downlink and special subframes.

The basic simulator needs a continuous stream of samples.

So let's fill the blank with silence.

SCTP: one to many sockets implementation

This reverts commit 31821838.

* put mutex lock around instance_prach
* destroy attributes

* join pthread_FH (ru_thread) once all condition variables have been set
* join RU FHTX only if it has been started (check as for pthread_create())
* join PRACH thread in the monolithic case
* send broadcast on condition variable cond_eNBs, as there can be multiple
  waits on it
* integrate stop_ru(*ru) into kill_RU_proc(*ru)
* Correct memory freeing

* init_td_thread()/init_te_thread() are only initialized depending on condition
  get_nprocs() > 2 && codingw
* apply the same the same for the functions kill_td_thread()/kill_te_thread()

Various problems were found with the basic simulator.

Variables used by various threads for synchronization need to
be initialized properly. That is before the various threads
start using them.

This goes for:
- UE->is_synchronized
- UE->proc.instance_cnt_synch
- UE->proc.instance_cnt_rxtx

The function "UE->rfdevice.trx_start_func" was called in
"UE_thread_synch" but should be called in "UE_thread" because
"UE_thread" is the one that calls "UE->rfdevice.trx_read_func"
and there is no guaranty that the call to "UE->rfdevice.trx_start_func"
is done before as it has to (it's in another thread).

And finally "pthread_cond_signal(&proc->cond_rxtx)" was called twice,
which may not be a problem but was certainly not intended. Plus
removing one call simplifies the code by removing some "if" logic,
which is a good thing per se.

This commit was not tested with a real UE and may thus introduce some
issues. Hopefully not!

Before this commit we were checking for UE->is_synchronized == 0
then we were waiting for a potentially active synch routine to
finish and then we were starting the synch routine again but the
synch routine that was running may have set UE->is_synchronized
to 1. This was leading to various problems, most notably the following
message repeated over and over in the UE log and the UE unable to
connect properly:

    [RRC]  [UE 0] Frame 377: OUT OF SYNC FROM eNB 0 (T310 active 0 : T310 0, N310 345, N311 0)

So let's wait for a potentially active synch routine to finish
before anything else.

Use common log mechanism in layer 3, mapping specific macros to common ones and extending common log utilities to support specific layer3 requirements

LOG_F replaced by LOG_DUMPMSG. Add a generic function to dump a buffer or message. Go on with LOG_M implementation improvement. Remove redundant options to enable/disable logs.

The configuration file has now to contain ENB_IPV4_ADDRESS_FOR_X2C and
ENB_PORT_FOR_X2C in the NETWORK_INTERFACES section.

For example:

    NETWORK_INTERFACES :
    {
        ENB_INTERFACE_NAME_FOR_S1_MME            = "eth0";
        ENB_IPV4_ADDRESS_FOR_S1_MME              = "192.168.12.111/24";
        ENB_INTERFACE_NAME_FOR_S1U               = "eth0";
        ENB_IPV4_ADDRESS_FOR_S1U                 = "192.168.12.111/24";
        ENB_PORT_FOR_S1U                         = 2152; # Spec 2152

        ENB_IPV4_ADDRESS_FOR_X2C                 = "192.168.12.111/24";
        ENB_PORT_FOR_X2C                         = 36422; # Spec 36422
    };

As reported by Robert Schmidt.

USRP addressess and clock sources can be configured in the configuration file with the RU section with comma separated IP addresses in 'sdr_addrs' and with strings "internal"/"external"/"gpsdo" in 'clock_src'.

TODO: Currently the driver picks the two first RX and TX channels when nb_tx and nb_rx are both set to 2. If a developers wants to force usage of two devices, 'set_rx_subdev_spec' and 'set_tx_subdev_spec' can be used to indicate to the driver so that antennas from separate devices will be used. To rephrase: until 4 antennas are supported by OAI, testing with two devices, so that antennas from both devices are used, requires manual configuration of which subdevices' antennas are used.

Conflicts:
	targets/ARCH/USRP/USERSPACE/LIB/usrp_lib.cpp

Compilation of UE softmodem failed.