pcuif_proto.h: extend RACH.ind with TRX / TS numbers

Since there can be multiple PDCH channels configured on different
timeslots, different TRXes, and BTSes, the PTCCH/U handling code
in OsmoPCU needs to know the exact origin of a given RACH.ind.

Otherwise, it is not known which subscriber originated a given
PTCCH/U indication, and hence it is impossible to send PTCCH/D
Timing Advance notification properly.

Fortunately, we can extend the RACH.ind message without even
bumping the protocol version, because every single PDU has a
fixed size defined by the largest message - INFO.ind. In case
if the actual message payload is smaller, the rest is filled
with a constant padding byte (0x00).

Older versions of OsmoPCU will consider the new fields as padding,
while the messages from older OsmoBTS versions will always have
both fields set to 0x00. Since C0/TS0 cannot be configured to
PDCH, this can be easily detected on the other end.

Change-Id: If209001885ffb14b64a8e808df3700d85a4b2ef9
Related: OS#1545
Vadim Yanitskiy 3 years ago
parent 78f58618f3
commit 17954da56c
  1. 2

@ -108,6 +108,8 @@ struct gsm_pcu_if_rach_ind {
uint16_t arfcn;
uint8_t is_11bit;
uint8_t burst_type;
uint8_t trx_nr;
uint8_t ts_nr;
} __attribute__ ((packed));
struct gsm_pcu_if_info_trx {