Restructure SI2quater generation
In preparation for extended SI2q messages:
* add SI2q-specific accessor macro
* add *_offset variables to gsm_bts struct
* internalize memory check while generating rest octets - introduce
budget concept (number of bits available in a given message)
* internalize *arfcn_size() functions as they are not needed outside of
si2q_num() anymore
* change rest octets generation to work with gsm_bts struct directly
* do not generate rest octets if no SI2q is necessary
* adjust unit tests accordingly (cosmetic changes only to avoid
regressions)
Requires: I92e12e91605bdab9916a3f665705287572434f74 in libosmocore
Change-Id: Ib554cf7ffc949a321571e1ae2ada1160e1b35fa6
Related: RT#8792
diff --git a/openbsc/src/libbsc/system_information.c b/openbsc/src/libbsc/system_information.c
index 37395f0..0496506 100644
--- a/openbsc/src/libbsc/system_information.c
+++ b/openbsc/src/libbsc/system_information.c
@@ -122,19 +122,22 @@
}
}
-unsigned earfcn_size(const struct osmo_earfcn_si2q *e)
+static inline unsigned earfcn_size(const struct gsm_bts *bts)
{
+ const struct osmo_earfcn_si2q *e = &bts->si_common.si2quater_neigh_list; /* EARFCN */
+
/* account for all the constant bits in append_earfcn() */
- return 25 + osmo_earfcn_bit_size(e);
+ return 25 + osmo_earfcn_bit_size_ext(e, bts->e_offset);
}
-unsigned uarfcn_size(const uint16_t *u, const uint16_t *sc, size_t u_len)
+static inline unsigned uarfcn_size(const struct gsm_bts *bts)
{
- /*account for all the constant bits in append_uarfcns() */
+ const uint16_t *u = bts->si_common.data.uarfcn_list;
+ uint16_t cu = u[bts->u_offset]; /* UARFCN */
+ /* account for all the constant bits in append_uarfcns() */
unsigned s = 7, append = 22, r = 0, i, st = 0, j, k;
- uint16_t cu = u[0];
- for (i = 0; i < u_len; i++) {
+ for (i = bts->u_offset; i < bts->si_common.uarfcn_length; i++) {
for (j = st, k = 0; j < i; j++, k++);
if (u[i] != cu) { /* we've reached new UARFCN */
r += (append + range1024_p(k));
@@ -144,18 +147,25 @@
}
/* add last UARFCN not covered by previous cycle */
- for (i = st, k = 0; i < u_len; i++, k++);
+ for (i = st, k = 0; i < bts->si_common.uarfcn_length; i++, k++);
return s + r + append + range1024_p(k);
}
-uint8_t si2q_num(const struct gsm_bts *bts)
+uint8_t si2q_num(struct gsm_bts *bts)
{
- const struct osmo_earfcn_si2q *e = &bts->si_common.si2quater_neigh_list; /* EARFCN */
- const uint16_t *u = bts->si_common.data.uarfcn_list, *sc = bts->si_common.data.scramble_list; /* UARFCN */
- size_t l = bts->si_common.uarfcn_length, e_sz = e ? earfcn_size(e) : 1, u_sz = l ? uarfcn_size(u, sc, l) : 1;
+ size_t est, e_sz = 1, u_sz = 1;
+
+ if (&bts->si_common.si2quater_neigh_list) /* EARFCN */
+ e_sz = earfcn_size(bts);
+
+ if (bts->si_common.uarfcn_length) /* UARFCN */
+ u_sz = uarfcn_size(bts);
+
/* 2 bits are used in between UARFCN and EARFCN structs */
- return 1 + (e_sz + u_sz) / (SI2Q_MAX_LEN - (SI2Q_MIN_LEN + 2));
+ est = 1 + (e_sz + u_sz) / (SI2Q_MAX_LEN - (SI2Q_MIN_LEN + 2));
+
+ return est;
}
/* 3GPP TS 44.018, Table 9.1.54.1 - prepend diversity bit to scrambling code */
@@ -191,8 +201,7 @@
return 0;
}
-int bts_uarfcn_add(struct gsm_bts *bts, uint16_t arfcn, uint16_t scramble,
- bool diversity)
+int bts_uarfcn_add(struct gsm_bts *bts, uint16_t arfcn, uint16_t scramble, bool diversity)
{
size_t len = bts->si_common.uarfcn_length, i, k = 0;
uint16_t scr, chk,
@@ -228,7 +237,7 @@
scl[k] = scr;
bts->si_common.uarfcn_length++;
- if (si2q_num(bts) < 2)
+ if (si2q_num(bts) < 2) /* FIXME: use SI2Q_MAX_NUM */
return 0;
bts_uarfcn_del(bts, arfcn, scramble);
@@ -662,11 +671,41 @@
return sizeof(*si2t);
}
+/* SI2quater messages are optional - we only generate them when neighbor UARFCNs or EARFCNs are configured */
+static inline bool si2quater_not_needed(struct gsm_bts *bts)
+{
+ unsigned i = MAX_EARFCN_LIST;
+
+ if (bts->si_common.si2quater_neigh_list.arfcn)
+ for (i = 0; i < MAX_EARFCN_LIST; i++)
+ if (bts->si_common.si2quater_neigh_list.arfcn[i] != OSMO_EARFCN_INVALID)
+ break;
+
+ if (!bts->si_common.uarfcn_length && i == MAX_EARFCN_LIST) {
+ bts->si_valid &= ~(1 << SYSINFO_TYPE_2quater); /* mark SI2q as invalid if no (E|U)ARFCNs are present */
+ return true;
+ }
+
+ return false;
+}
+
+size_t si2q_earfcn_count(const struct osmo_earfcn_si2q *e)
+{
+ unsigned i, ret = 0;
+ for (i = 0; i < e->length; i++)
+ if (e->arfcn[i] != OSMO_EARFCN_INVALID)
+ ret++;
+
+ return ret;
+}
+
static int generate_si2quater(enum osmo_sysinfo_type t, struct gsm_bts *bts)
{
- int rc, i = MAX_EARFCN_LIST;
- struct gsm48_system_information_type_2quater *si2q =
- (struct gsm48_system_information_type_2quater *) GSM_BTS_SI(bts, t);
+ int rc;
+ struct gsm48_system_information_type_2quater *si2q = GSM_BTS_SI2Q(bts);
+
+ if (si2quater_not_needed(bts)) /* generate rest_octets for SI2q only when necessary */
+ return GSM_MACBLOCK_LEN;
memset(si2q, GSM_MACBLOCK_PADDING, GSM_MACBLOCK_LEN);
@@ -675,22 +714,10 @@
si2q->header.skip_indicator = 0;
si2q->header.system_information = GSM48_MT_RR_SYSINFO_2quater;
- rc = rest_octets_si2quater(si2q->rest_octets, bts->si2q_index, bts->si2q_count,
- &bts->si_common.si2quater_neigh_list,
- bts->si_common.data.uarfcn_list,
- bts->si_common.data.scramble_list,
- bts->si_common.uarfcn_length);
+ rc = rest_octets_si2quater(si2q->rest_octets, bts);
if (rc < 0)
return rc;
- if (bts->si_common.si2quater_neigh_list.arfcn)
- for (i = 0; i < MAX_EARFCN_LIST; i++)
- if (bts->si_common.si2quater_neigh_list.arfcn[i] !=
- OSMO_EARFCN_INVALID)
- break;
- if (!bts->si_common.uarfcn_length && i == MAX_EARFCN_LIST)
- bts->si_valid &= ~(1 << SYSINFO_TYPE_2quater);
-
return sizeof(*si2q) + rc;
}