This is a big change to the way we use the subscriber
connection. From now on it is is dynamically allocated
and we will slowly move from a 1:1 lchan to conn to
having more than one lchan per connection.
This is the first commit, the subscr_con* methods will
move to gsm_data once the use_count is removed from the
connection, the freeing of the connection will also change.
The Channel Activate might be sent to a different TRX than the
Immediate Assignment. So we need to make sure that the channel
is activated before we send the immediate assignment for the RACH.
Another reason for that is according to GSM 08.58 we should take
the frame number from the activate and use it for the starting
time inside the immediate assignment message. We obviously do not
do this yet.
The code assumes that the BTS will either respond with a CHAN ACK
or a CHAN NACK if not the lchan will remain in the request state.
gmtime(NULL) returns NULL at least in glibc and *can not* be used as
time(NULL). Since we compare two time_t values when checking the validity
period this can be replaced by time(NULL)
The value of the in_addr might not be 32 bit aligned and reading
it can generate an alignment error on ARM. Fix it by using memcpy
to copy the data into a local variable.
There are many more potential alignment issues that we will fix
when we hit them.
For Siemens BS-11, the 'length' value of the ARFCN_LIST IE is interpreted in
violation of the spec. The spec says it is a length in octets, while Siemens
treats it as 'count of 16bit ARFCN values'.
Also, make sure the bit ordering in the pre-computed MA is correct,
as well as the cell channel description of the target cell being
present in the HO CMD.
We now compute the Cell Channel Description for SI 1 by bit-wise
OR of the ARFCN bitmask of each timeslot on all the TRX of the BTS.
Also, support generating a GSM 04.08 Channel Description IE for
the hopping case (with HSN/MAIO instead of ARFCN).
What's still missing now: Sending the 04.08 Mobile Allocation IE
In some cases, we get a DL_INFORMATION_IND with a wrong channel
number, and only in the DL_ESTABLISH_IND we will see the real
channel number that is to be used for this (TEI, SAPI) tuple.
Now it properly parses message types and IEs that are defined different
depending on the BTS vendor / A-bis implementor. This fixes a lot of
decoding bugs with Siemens BS-11 traces.
Do not use the lchan for the paging but operate on the
subscriber_connection, change the signals too to not carry
the lchan but the subscriber connection... the silent call
and vty code still assume there is a lchan inside the
subscriber connection.
Holger Hans Peter Freyther
Harald Welte