gsm: Introduce API osmo_gsm48_rest_octets_si13_decode
Related: SYS#5358
Change-Id: I74fb0a3afc1ac4aadbfc609b882d929401f790eb
diff --git a/src/gsm/gsm48_rest_octets.c b/src/gsm/gsm48_rest_octets.c
index 1bab8e0..77fd349 100644
--- a/src/gsm/gsm48_rest_octets.c
+++ b/src/gsm/gsm48_rest_octets.c
@@ -749,6 +749,119 @@
return bv.data_len;
}
+
+static unsigned int decode_t3192(unsigned int t3192)
+{
+ /* See also 3GPP TS 44.060
+ Table 12.24.2: GPRS Cell Options information element details */
+ static const unsigned int decode_t3192_tbl[8] = {500, 1000, 1500, 0, 80, 120, 160, 200};
+ OSMO_ASSERT(t3192 <= 7);
+ return decode_t3192_tbl[t3192];
+}
+
+static unsigned int decode_drx_timer(unsigned int drx)
+{
+ static const unsigned int decode_drx_timer_tbl[8] = {0, 1, 2, 4, 8, 16, 32, 64};
+ OSMO_ASSERT(drx <= 7);
+ return decode_drx_timer_tbl[drx];
+}
+
+static int decode_gprs_cell_opt(struct osmo_gprs_cell_options *gco, struct bitvec *bv)
+{
+ gco->nmo = bitvec_get_uint(bv, 2);
+ gco->t3168 = (bitvec_get_uint(bv, 3) + 1) * 500;
+ gco->t3192 = decode_t3192(bitvec_get_uint(bv, 3));
+ gco->drx_timer_max = decode_drx_timer(bitvec_get_uint(bv, 3));
+
+ /* ACCESS_BURST_TYPE: */
+ bitvec_get_uint(bv, 1);
+ /* CONTROL_ACK_TYPE: */
+ gco->ctrl_ack_type_use_block = bitvec_get_uint(bv, 1);
+ gco->bs_cv_max = bitvec_get_uint(bv, 4);
+
+ if (bitvec_get_uint(bv, 1)) {
+ bitvec_get_uint(bv, 3); /* DEC */
+ bitvec_get_uint(bv, 3); /* INC */
+ bitvec_get_uint(bv, 3); /* MAX */
+ }
+
+ if (bitvec_get_uint(bv, 1)) {
+ int ext_len = bitvec_get_uint(bv, 6);
+ if (ext_len < 0)
+ return ext_len;
+ unsigned int cur_bit = bv->cur_bit;
+ /* Extension Information */
+ /* R99 extension: */
+ gco->ext_info.egprs_supported = bitvec_get_uint(bv, 1);
+ if (gco->ext_info.egprs_supported) {
+ gco->ext_info.use_egprs_p_ch_req = !bitvec_get_uint(bv, 1);
+ gco->ext_info.bep_period = bitvec_get_uint(bv, 4);
+ }
+ gco->ext_info.pfc_supported = bitvec_get_uint(bv, 1);
+ gco->ext_info.dtm_supported = bitvec_get_uint(bv, 1);
+ gco->ext_info.bss_paging_coordination = bitvec_get_uint(bv, 1);
+ /* REL-4 extension: */
+ gco->ext_info.ccn_active = bitvec_get_uint(bv, 1);
+ bitvec_get_uint(bv, 1); /* NW_EXT_UTBF */
+ bv->cur_bit = cur_bit + ext_len + 1;
+ }
+ return 0;
+}
+
+static void decode_gprs_pwr_ctrl_pars(struct osmo_gprs_power_ctrl_pars *pcp, struct bitvec *bv)
+{
+ pcp->alpha = bitvec_get_uint(bv, 4);
+ pcp->t_avg_w = bitvec_get_uint(bv,5);
+ pcp->t_avg_t = bitvec_get_uint(bv, 5);
+ pcp->pc_meas_chan = bitvec_get_uint(bv, 1);
+ pcp->n_avg_i = bitvec_get_uint(bv, 4);
+}
+
+/*! Decode SI13 Rest Octests (04.08 Chapter 10.5.2.37b).
+ * \param[out] si13 decoded SI13 rest octets
+ * \param[in] encoded SI13 rest octets
+ * \returns parsed bits on success, negative on error */
+int osmo_gsm48_rest_octets_si13_decode(struct osmo_gsm48_si13_info *si13, const uint8_t *data)
+{
+ struct osmo_gprs_cell_options *co = &si13->cell_opts;
+ struct osmo_gprs_power_ctrl_pars *pcp = &si13->pwr_ctrl_pars;
+ struct bitvec bv;
+ int rc;
+
+ memset(&bv, 0, sizeof(bv));
+ bv.data = (uint8_t *) data;
+ bv.data_len = 20;
+
+ memset(si13, 0, sizeof(*si13));
+
+
+ if (bitvec_get_bit_high(&bv) == H) {
+ si13->bcch_change_mark = bitvec_get_uint(&bv, 3);
+ si13->si_change_field = bitvec_get_uint(&bv, 4);
+ if (bitvec_get_uint(&bv, 1)) {
+ si13->bcch_change_mark = bitvec_get_uint(&bv, 2);
+ /* FIXME: implement parsing GPRS Mobile Allocation IE */
+ return -ENOTSUP;
+ }
+ if (bitvec_get_uint(&bv, 1)) {
+ /* PBCCH present in cell */
+ /* FIXME: parse not implemented */
+ return -ENOTSUP;
+ } else {
+ /* PBCCH not present in cell */
+ si13->rac = bitvec_get_uint(&bv, 8);
+ si13->spgc_ccch_sup = bitvec_get_uint(&bv, 1);
+ si13->prio_acc_thr = bitvec_get_uint(&bv, 3);
+ si13->net_ctrl_ord = bitvec_get_uint(&bv, 2);
+ if ((rc = decode_gprs_cell_opt(co, &bv)) < 0)
+ return rc;
+
+ decode_gprs_pwr_ctrl_pars(pcp, &bv);
+ }
+ }
+ return bv.cur_bit;
+}
+
/* GPRS Mobile Allocation as per TS 04.60 Chapter 12.10a:
< GPRS Mobile Allocation IE > ::=
< HSN : bit (6) >
diff --git a/src/gsm/libosmogsm.map b/src/gsm/libosmogsm.map
index efa23e6..0ea0678 100644
--- a/src/gsm/libosmogsm.map
+++ b/src/gsm/libosmogsm.map
@@ -320,6 +320,7 @@
osmo_gsm48_rest_octets_si6_encode;
osmo_gsm48_rest_octets_si3_encode;
osmo_gsm48_rest_octets_si4_encode;
+osmo_gsm48_rest_octets_si13_decode;
osmo_gsm48_rest_octets_si13_encode;
osmo_gsm48_rest_octets_si3_decode;
osmo_gsm48_rest_octets_si4_decode;