diff options
author | Max <msuraev@sysmocom.de> | 2017-09-29 14:10:24 +0200 |
---|---|---|
committer | Max <msuraev@sysmocom.de> | 2017-10-09 10:08:16 +0000 |
commit | 081cebaa6ddf3abebb93025c7eb430f0c9844016 (patch) | |
tree | 48282fc76a9a910e74fee44842d221c463bbfa3b /src/libbsc/system_information.c | |
parent | ff20215db27b390e29ca44e5a63d9e870fa7825d (diff) |
SI2q: cleanup UARFCN addition
* expand comments, fix typos
* constify parameter
* move try-add-adjust routine into separate function to facilitate
further modifications
* remove excessive checks and unnecessary return values
* move (UARFCN, Scrambling Code) tuple uniqueness check into separate
function and use it early
Change-Id: Ia72f848dec40723510ca56868e08081804227d47
Related: OS#2357
Diffstat (limited to 'src/libbsc/system_information.c')
-rw-r--r-- | src/libbsc/system_information.c | 81 |
1 files changed, 47 insertions, 34 deletions
diff --git a/src/libbsc/system_information.c b/src/libbsc/system_information.c index 7bdb80a00..761e8482b 100644 --- a/src/libbsc/system_information.c +++ b/src/libbsc/system_information.c @@ -182,7 +182,7 @@ uint8_t si2q_num(struct gsm_bts *bts) int rc = make_si2quaters(bts, true); uint8_t num = bts->si2q_index + 1; /* number of SI2quater messages */ - /* N. B: si2q_num() should NEVER be called during actualSI2q rest octets generation + /* N. B: si2q_num() should NEVER be called during actual SI2q rest octets generation we're not re-entrant because of the following code: */ bts->u_offset = 0; bts->e_offset = 0; @@ -239,27 +239,41 @@ int bts_earfcn_add(struct gsm_bts *bts, uint16_t earfcn, uint8_t thresh_hi, uint return r; } -int bts_uarfcn_del(struct gsm_bts *bts, uint16_t arfcn, uint16_t scramble) +/* Scrambling Code as defined in 3GPP TS 25.213 is 9 bit long so number below is unreacheable upper bound */ +#define SC_BOUND 600 + +/* Find position for a given UARFCN (take SC into consideration if it's available) in a sorted list + N. B: we rely on the assumption that (uarfcn, scramble) tuple is unique in the lists */ +static int uarfcn_sc_pos(const struct gsm_bts *bts, uint16_t uarfcn, uint16_t scramble) { - uint16_t sc0 = encode_fdd(scramble, false), sc1 = encode_fdd(scramble, true), - *ual = bts->si_common.data.uarfcn_list, - *scl = bts->si_common.data.scramble_list; - size_t len = bts->si_common.uarfcn_length, i; - for (i = 0; i < len; i++) { - if (arfcn == ual[i] && (sc0 == scl[i] || sc1 == scl[i])) { - /* we rely on the assumption that (uarfcn, scramble) - tuple is unique in the lists */ - if (i != len - 1) { /* move the tail if necessary */ - memmove(ual + i, ual + i + 1, 2 * (len - i + 1)); - memmove(scl + i, scl + i + 1, 2 * (len - i + 1)); - } - break; + const uint16_t *sc = bts->si_common.data.scramble_list; + uint16_t i, scramble0 = encode_fdd(scramble, false), scramble1 = encode_fdd(scramble, true); + for (i = 0; i < bts->si_common.uarfcn_length; i++) + if (uarfcn == bts->si_common.data.uarfcn_list[i]) { + if (scramble < SC_BOUND) { + if (scramble0 == sc[i] || scramble1 == sc[i]) + return i; + } else + return i; } - } - if (i == len) + return -1; +} + +int bts_uarfcn_del(struct gsm_bts *bts, uint16_t arfcn, uint16_t scramble) +{ + uint16_t *ual = bts->si_common.data.uarfcn_list, *scl = bts->si_common.data.scramble_list; + size_t len = bts->si_common.uarfcn_length; + int pos = uarfcn_sc_pos(bts, arfcn, scramble); + + if (pos < 0) return -EINVAL; + if (pos != len - 1) { /* move the tail if necessary */ + memmove(ual + pos, ual + pos + 1, 2 * (len - pos + 1)); + memmove(scl + pos, scl + pos + 1, 2 * (len - pos + 1)); + } + bts->si_common.uarfcn_length--; return 0; } @@ -267,29 +281,27 @@ int bts_uarfcn_del(struct gsm_bts *bts, uint16_t arfcn, uint16_t scramble) 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, + uint8_t si2q; + int pos = uarfcn_sc_pos(bts, arfcn, scramble); + uint16_t scr = diversity ? encode_fdd(scramble, true) : encode_fdd(scramble, false), *ual = bts->si_common.data.uarfcn_list, - *scl = bts->si_common.data.scramble_list, - scramble1 = encode_fdd(scramble, true), - scramble0 = encode_fdd(scramble, false); - - scr = diversity ? scramble1 : scramble0; - chk = diversity ? scramble0 : scramble1; + *scl = bts->si_common.data.scramble_list; if (len == MAX_EARFCN_LIST) return -ENOMEM; - for (i = 0; i < len; i++) /* find the position of arfcn if any */ - if (arfcn == ual[i]) - break; + if (pos >= 0) + return -EADDRINUSE; + + /* find the suitable position for arfcn if any */ + pos = uarfcn_sc_pos(bts, arfcn, SC_BOUND); + i = (pos < 0) ? len : pos; - for (k = 0; i < len; i++) { - if (arfcn == ual[i] && (scr == scl[i] || chk == scl[i])) - return -EADDRINUSE; + for (k = 0; i < len; i++) if (scr > scl[i]) k = i + 1; - } - /* we keep lists sorted by scramble code: + + /* we keep lists sorted by scramble code of a given UARFCN: insert into appropriate position and move the tail */ if (len - k) { memmove(ual + k + 1, ual + k, (len - k) * 2); @@ -299,9 +311,10 @@ int bts_uarfcn_add(struct gsm_bts *bts, uint16_t arfcn, uint16_t scramble, bool ual[k] = arfcn; scl[k] = scr; bts->si_common.uarfcn_length++; + si2q = si2q_num(bts); - if (si2q_num(bts) <= SI2Q_MAX_NUM) { - bts->si2q_count = si2q_num(bts) - 1; + if (si2q <= SI2Q_MAX_NUM) { + bts->si2q_count = si2q - 1; return 0; } |