From 78f532992a88bd720c1d576bb940d53057f3c219 Mon Sep 17 00:00:00 2001 From: Max Date: Fri, 29 Sep 2017 14:10:24 +0200 Subject: [PATCH] SI2q: cleanup UARFCN addition * fix comment typo * constify parameter * move try-add-adjust routine into separate function to facilitate further modifications * remove excessive checks and unnecessary return values Change-Id: Ia72f848dec40723510ca56868e08081804227d47 Related: OS#2357 --- src/libbsc/rest_octets.c | 97 +++++++++++++++------------------ src/libbsc/system_information.c | 2 +- 2 files changed, 44 insertions(+), 55 deletions(-) diff --git a/src/libbsc/rest_octets.c b/src/libbsc/rest_octets.c index 09c4a9014..b1516ecc4 100644 --- a/src/libbsc/rest_octets.c +++ b/src/libbsc/rest_octets.c @@ -232,7 +232,7 @@ static inline int f0_helper(int *sc, size_t length, uint8_t *chan_list) } /* Estimate how many bits it'll take to append single FDD UARFCN */ -static inline int append_utran_fdd_length(uint16_t u, int *sc, size_t sc_len, size_t length) +static inline int append_utran_fdd_length(uint16_t u, const int *sc, size_t sc_len, size_t length) { uint8_t chan_list[16] = { 0 }; int tmp[sc_len], f0; @@ -274,18 +274,42 @@ static inline int append_utran_fdd(struct bitvec *bv, uint16_t u, int *sc, size_ return 21 + range1024_p(length); } -/* Append multiple FDD UARFCNs */ -static inline int append_uarfcns(struct bitvec *bv, struct gsm_bts *bts, uint8_t budget) +static inline int try_adding_uarfcn(struct bitvec *bv, struct gsm_bts *bts, uint16_t uarfcn, + uint8_t num_sc, uint8_t start_pos, uint8_t budget) { - const uint16_t *u = bts->si_common.data.uarfcn_list, *sc = bts->si_common.data.scramble_list; - int i, j, k, rc, st = 0, a[bts->si_common.uarfcn_length]; + int i, k, rc, a[bts->si_common.uarfcn_length]; + + if (budget < 23) + return -ENOMEM; + + /* copy corresponding Scrambling Codes: range encoder make in-place modifications */ + for (i = start_pos, k = 0; i < num_sc; a[k++] = bts->si_common.data.scramble_list[i++]); + + /* estimate bit length requirements */ + rc = append_utran_fdd_length(uarfcn, a, bts->si_common.uarfcn_length, k); + if (rc < 0) + return rc; /* range encoder failure */ + + if (budget - rc <= 0) + return -ENOMEM; /* we have ran out of budget in current SI2q */ + + /* compute next offset */ + bts->u_offset += k; + + return budget - append_utran_fdd(bv, uarfcn, a, k); +} + +/* Append multiple FDD UARFCNs */ +static inline void append_uarfcns(struct bitvec *bv, struct gsm_bts *bts, uint8_t budget) +{ + const uint16_t *u = bts->si_common.data.uarfcn_list; + int i, rem = budget - 7, st = 0; /* account for constant bits right away */ uint16_t cu = u[bts->u_offset]; /* caller ensures that length is positive */ - uint8_t rem = budget - 7, offset_diff; /* account for constant bits right away */ OSMO_ASSERT(budget <= SI2Q_MAX_LEN); if (budget <= 7) - return -ENOMEM; + return; /* 3G Neighbour Cell Description */ bitvec_set_bit(bv, 1); @@ -299,53 +323,24 @@ static inline int append_uarfcns(struct bitvec *bv, struct gsm_bts *bts, uint8_t /* No Bandwidth_FDD */ bitvec_set_bit(bv, 0); - for (i = bts->u_offset; i < bts->si_common.uarfcn_length; i++) { - offset_diff = 0; - for (j = st, k = 0; j < i; j++) { - a[k++] = sc[j]; /* copy corresponding SCs */ - offset_diff++; /* compute proper offset step */ - } + for (i = bts->u_offset; i <= bts->si_common.uarfcn_length; i++) if (u[i] != cu) { /* we've reached new UARFCN */ - rc = append_utran_fdd_length(cu, a, bts->si_common.uarfcn_length, k); - if (rc < 0) { /* estimate bit length requirements */ - return rc; - } + rem = try_adding_uarfcn(bv, bts, cu, i, st, rem); + if (rem < 0) + break; - if (rem - rc <= 0) - break; /* we have ran out of budget in current SI2q */ - else { - rem -= append_utran_fdd(bv, cu, a, k); - bts->u_offset += offset_diff; - } - cu = u[i]; - st = i; /* update start position */ + if (i < bts->si_common.uarfcn_length) { + cu = u[i]; + st = i; + } else + break; } - } - - if (rem > 22) { /* add last UARFCN not covered by previous cycle if it could possibly fit into budget */ - offset_diff = 0; - for (i = st, k = 0; i < bts->si_common.uarfcn_length; i++) { - a[k++] = sc[i]; - offset_diff++; - } - rc = append_utran_fdd_length(cu, a, bts->si_common.uarfcn_length, k); - if (rc < 0) { - return rc; - } - - if (rem - rc >= 0) { - rem -= append_utran_fdd(bv, cu, a, k); - bts->u_offset += offset_diff; - } - } /* stop bit - end of Repeated UTRAN FDD Neighbour Cells */ bitvec_set_bit(bv, 0); /* UTRAN TDD Description */ bitvec_set_bit(bv, 0); - - return 0; } /* generate SI2quater rest octets: 3GPP TS 44.018 ยง 10.5.2.33b */ @@ -393,15 +388,9 @@ int rest_octets_si2quater(uint8_t *data, struct gsm_bts *bts) bitvec_set_bit(&bv, 0); rc = SI2Q_MAX_LEN - (bv.cur_bit + 3); - if (rc > 0 && bts->si_common.uarfcn_length - bts->u_offset > 0) { - rc = append_uarfcns(&bv, bts, rc); - if (rc < 0) { - LOGP(DRR, LOGL_ERROR, "SI2quater [%u/%u]: failed to append %zu UARFCNs due to range encoding " - "failure: %s\n", - bts->si2q_index, bts->si2q_count, bts->si_common.uarfcn_length, strerror(-rc)); - return rc; - } - } else /* No 3G Neighbour Cell Description */ + if (rc > 0 && bts->si_common.uarfcn_length - bts->u_offset > 0) + append_uarfcns(&bv, bts, rc); + else /* No 3G Neighbour Cell Description */ bitvec_set_bit(&bv, 0); /* No 3G Measurement Parameters Description */ diff --git a/src/libbsc/system_information.c b/src/libbsc/system_information.c index 7bdb80a00..8c37f9c24 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;