RR Release Cell selection IE: fix repeated EARFCNs encoding
3GPP 44.018 10.5.2.1e defines the EARFCNs encoded in the 'Cell selection
indicator after release of all TCH and SDCCH IE' as follows:
<Cell Selection Indicator after release of all TCH and SDCCH value part> ::=
[...]
| 011 { 1 <E-UTRAN Description : < E-UTRAN Description struct >> } ** 0
So after a 3-bit discriminator of '3' there can be multiple E-UTRAN
Descriptions, and each of them starts with a '1' bit to indicate that another
item follows. Finally there is a '0' bit to indicate the list end.
Before this patch, osmo-bsc only encoded the first '1' bit, and failed to
repeat this before each following E-UTRAN Description. Fix that by moving the
'1' encoding into the loop.
The final '0' was missing. Add it.
With these changes, adjust the size calculation in
CELL_SEL_IND_AFTER_REL_MAX_BITS to match.
Also fix CELL_SEL_IND_AFTER_REL_MAX_BYTES by using OSMO_BYTES_FOR_BITS()
instead of the inaccurate (n/8)+1.
A test for this is in I882c5e1f70bcc4833fc837a95c900ce291919cc5
(osmo-ttcn3-hacks).
Related: SYS#4871 SYS#4872
Change-Id: I59e427e4ebb1c6af99b27a15c40fed82457ac8ab
diff --git a/src/osmo-bsc/gsm_04_08_rr.c b/src/osmo-bsc/gsm_04_08_rr.c
index f47c31f..f425b16 100644
--- a/src/osmo-bsc/gsm_04_08_rr.c
+++ b/src/osmo-bsc/gsm_04_08_rr.c
@@ -238,8 +238,8 @@
}
-#define CELL_SEL_IND_AFTER_REL_MAX_BITS (4+MAX_EARFCN_LIST*19)
-#define CELL_SEL_IND_AFTER_REL_MAX_BYTES ((CELL_SEL_IND_AFTER_REL_MAX_BITS/8)+1)
+#define CELL_SEL_IND_AFTER_REL_MAX_BITS (3+MAX_EARFCN_LIST*20+1)
+#define CELL_SEL_IND_AFTER_REL_MAX_BYTES OSMO_BYTES_FOR_BITS(CELL_SEL_IND_AFTER_REL_MAX_BITS)
/* Generate a CSN.1 encoded "Cell Selection Indicator after release of all TCH and SDCCH"
* as per TF 44.018 version 15.3.0 Table 10.5.2.1e.1. This only generates the "value"
@@ -255,17 +255,18 @@
/* E-UTRAN Description */
bitvec_set_uint(&bv, 3, 3);
- bitvec_set_bit(&bv, 1);
for (i = 0; i < MAX_EARFCN_LIST; i++) {
const struct osmo_earfcn_si2q *e = &bts->si_common.si2quater_neigh_list;
if (e->arfcn[i] == OSMO_EARFCN_INVALID)
continue;
- if (bitvec_tailroom_bits(&bv) < 19) {
+ /* tailroom must fit one more EARFCN (20 bits), plus the final list term bit. */
+ if (bitvec_tailroom_bits(&bv) < 21) {
LOGP(DRR, LOGL_NOTICE, "%s: Not enough room to store EARFCN %u in the "
"Cell Selection Indicator IE\n", gsm_bts_name(bts), e->arfcn[i]);
} else {
+ bitvec_set_bit(&bv, 1);
bitvec_set_uint(&bv, e->arfcn[i], 16);
/* No "Measurement Bandwidth" */
bitvec_set_bit(&bv, 0);
@@ -276,6 +277,9 @@
}
}
+ /* list term */
+ bitvec_set_bit(&bv, 0);
+
rc = bitvec_used_bytes(&bv);
if (rc == 1) {