diff options
Diffstat (limited to 'openbsc/src')
-rw-r--r-- | openbsc/src/arfcn_list_range.c | 194 | ||||
-rw-r--r-- | openbsc/src/libbsc/Makefile.am | 3 | ||||
-rw-r--r-- | openbsc/src/libbsc/arfcn_range_encode.c | 305 | ||||
-rw-r--r-- | openbsc/src/libbsc/system_information.c | 136 |
4 files changed, 418 insertions, 220 deletions
diff --git a/openbsc/src/arfcn_list_range.c b/openbsc/src/arfcn_list_range.c deleted file mode 100644 index b7f6e0ffd..000000000 --- a/openbsc/src/arfcn_list_range.c +++ /dev/null @@ -1,194 +0,0 @@ -/* C-Implementation of the Algorithm described in Appendix J of GSM TS 44.018,
- * (C) 2009 by Dirk Hakkesteegt <dirk@hakkesteegt.org>
- *
- * All Rights Reserved
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU Affero General Public License as published by
- * the Free Software Foundation; either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU Affero General Public License for more details.
- *
- * You should have received a copy of the GNU Affero General Public License
- * along with this program. If not, see <http://www.gnu.org/licenses/>.
- *
- */
-/* Annex J.3 indicates that at least in one BA list, we can never have more
- * than 29 frequencies within the 16byte limit */
-#define MAX_ARRFCNS 29
-
-/*****************************************************************************
-* NAME : smod
-* DESCRIPTION : n smod m indicates the offset remainder of the euclidian
-* division of n by m
-* INPUT : n, m
-* OUTPUT : n smod m
-* RETURNS :
-* Errorcodes :
-******************************************************************************/
-static int smod(int n, int m)
-{
- int result = n % m;
- if (result < 0)
- result += m;
-
- if (result == 0)
- result = m;
-
- return result;
-}
-
-/*****************************************************************************
-* NAME : mod
-* DESCRIPTION : n mod m indicates the remainder of the euclidian division of
-* n by m
-* INPUT : n, m
-* OUTPUT : n mod m
-* RETURNS :
-* Errorcodes :
-******************************************************************************/
-static int mod(int n, int m)
-{
- int result = n % m;
- if (result < 0)
- result += m;
-
- return result;
-}
-
-/*****************************************************************************
-* NAME : greatest_power_of_2_le_to
-* DESCRIPTION : Calculates the greatest power of 2 that is lesser or equal
-* to the input value;
-* INPUT :
-* OUTPUT :
-* RETURNS :
-* Errorcodes :
-******************************************************************************/
-static int greatest_power_of_2_le_to(int input)
-{
- int check_val = 1;
- while (check_val <= input)
- check_val *= 2;
-
- return check_val / 2;
-}
-
-/*****************************************************************************
-* NAME : ENCODE_SUBTREE
-* DESCRIPTION : Recursive encoding routine based on 3GPP TS44.018 Annex J.4
-* INPUT : index: current position in the W list
-* set: the array to be encoded
-* range: the current range
-* set_size: number of elements in set
-* OUTPUT : W: the array of results
-* RETURNS :
-* Errorcodes :
-******************************************************************************/
-static void encode_subtree(int index, int *set, int range, int set_size, int *W)
-{
- int index_in_set = 0;
- int N, J, I, x;
- int subset[18];
- int subset_index, origin_value;
-
- /* Check if this is a leaf */
- if (set_size == 0) {
- W[index] = 0;
- return;
- } else {
- if (set_size == 1) {
- W[index] = 1 + set[1];
- return;
- }
- }
-
- for (I = 1; I <= set_size; I++) {
- N = 0;
- for (J = 1; J <= set_size; J++) {
- x = set[J] - set[I];
- x = mod(x, range);
- if (x <= (range-1)/2)
- N++;
- }
- if (N-1 == (set_size-1) / 2) {
- index_in_set = I;
- break;
- }
- }
-
- W[index] = set[index_in_set] + 1;
-
- /* Left subset */
- subset[0] = 0;
- origin_value = mod((set[index_in_set] + (range-1) / 2 + 1), range);
- subset_index = 1;
- for (I = 1; I <= set_size; I++) {
- if (mod((set[I]-origin_value), range) < range/2) {
- subset[subset_index] = mod((set[I] - origin_value), range);
- subset_index++;
- subset[subset_index] = 0;
- }
- }
- encode_subtree(index + greatest_power_of_2_le_to(index),
- subset, range / 2, subset_index-1, W);
-
- /* Right subset */
- subset[0] = 0;
- origin_value = mod((set[index_in_set] + 1), range);
- subset_index=1;
- for (I = 1; I<= set_size; I++) {
- if (mod((set[I]-origin_value), range) < range/2) {
- subset[subset_index] = mod((set[I] - origin_value), range);
- subset_index++;
- subset[subset_index] = 0;
- }
- }
- encode_subtree(index + 2*greatest_power_of_2_le_to(index),
- subset, (range-1)/2, subset_index-1, W);
-}
-
-/*****************************************************************************
-* NAME : CalcARFCN
-* DESCRIPTION : Calculate the ARFCN list
-* INPUT : F: the list of input frequencies. MUST BE SORTED!
-* count: the number of elements in the F list
-* range: the encoding range (default: range 512)
-* OUTPUT : W: the list of W values
-* RETURNS :
-* Errorcodes :
-******************************************************************************/
-static void CalcARFCN(const unsigned int *F, int *W, unsigned int count, unsigned int range)
-{
- int i;
- int Fd[MAX_ARFCNS+1];
-
- W[0] = F[0];
- for (i = 1; i < count; i++) {
- Fd[i] = F[i] - F[0] - 1;
- }
- encode_subtree(1, Fd, range-1, count-1, W);
-}
-
-int bitvec2arfcn_list_range(uint8_t *range, struct bitvec *bv, uint16_t range)
-{
- unsigned int i, idx = 0;
- int F[MAX_ARFCNS+1];
- int W[MAX_ARFCNS+1];
-
- /* build an array of integers from the bitmask */
- for (i = 0; i < bv->data_len*8; i++) {
- if (bitvec_get_bit_pos(bv, i))
- F[idx++] = i;
- }
- /* Perform the actual algorithm to calculate the 'W' values */
- CalcARFCN(F, W, idx, range);
-
- /* FIXME: Encode the 'W' values into the actual format as used in 04.08 */
-
- return -EIO;
-}
diff --git a/openbsc/src/libbsc/Makefile.am b/openbsc/src/libbsc/Makefile.am index 7cb1e6e00..21cbccd31 100644 --- a/openbsc/src/libbsc/Makefile.am +++ b/openbsc/src/libbsc/Makefile.am @@ -22,5 +22,6 @@ libbsc_a_SOURCES = abis_nm.c abis_nm_vty.c \ e1_config.c \ bsc_api.c bsc_msc.c bsc_vty.c \ gsm_04_08_utils.c \ - bsc_init.c bts_init.c bsc_rf_ctrl.c + bsc_init.c bts_init.c bsc_rf_ctrl.c \ + arfcn_range_encode.c diff --git a/openbsc/src/libbsc/arfcn_range_encode.c b/openbsc/src/libbsc/arfcn_range_encode.c new file mode 100644 index 000000000..02a75a53c --- /dev/null +++ b/openbsc/src/libbsc/arfcn_range_encode.c @@ -0,0 +1,305 @@ +/* gsm 04.08 system information (si) encoding and decoding + * 3gpp ts 04.08 version 7.21.0 release 1998 / etsi ts 100 940 v7.21.0 */ + +/* + * (C) 2012 Holger Hans Peter Freyther + * (C) 2012 by On-Waves + * All Rights Reserved + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU Affero General Public License as published by + * the Free Software Foundation; either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU Affero General Public License for more details. + * + * You should have received a copy of the GNU Affero General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <openbsc/arfcn_range_encode.h> +#include <openbsc/debug.h> + +#include <osmocom/gsm/protocol/gsm_04_08.h> + +#include <osmocom/core/utils.h> + +int greatest_power_of_2_lesser_or_equal_to(int index) +{ + int power_of_2 = 1; + + do { + power_of_2 *= 2; + } while (power_of_2 <= index); + + /* now go back one step */ + return power_of_2 / 2; +} + +static inline int mod(int data, int range) +{ + int res = data % range; + while (res < 0) + res += range; + return res; +} + +/** + * Determine at which index to split the ARFCNs to create an + * equally size partition for the given range. Return -1 if + * no such partition exists. + */ +int range_enc_find_index(const int range, const int *freqs, const int size) +{ + int i, j, n; + + const int RANGE_DELTA = (range - 1) / 2; + + for (i = 0; i < size; ++i) { + n = 0; + for (j = 0; j < size; ++j) { + if (mod(freqs[j] - freqs[i], range) <= RANGE_DELTA) + n += 1; + } + + if (n - 1 == (size - 1) / 2) + return i; + } + + return -1; +} + +/** + * Range encode the ARFCN list. + * \param range The range to use. + * \param arfcns The list of ARFCNs + * \param size The size of the list of ARFCNs + * \param out Place to store the W(i) output. + */ +int range_enc_arfcns(const int range, + const int *arfcns, int size, int *out, + const int index) +{ + int split_at; + int i; + + /* + * The below is a GNU extension and we can remove it when + * we move to a quicksort like in-situ swap with the pivot. + */ + int arfcns_left[size / 2]; + int arfcns_right[size / 2]; + int l_size; + int r_size; + int l_origin; + int r_origin; + + + /* Test the two recursion anchors and stop processing */ + if (size == 0) + return 0; + + if (size == 1) { + out[index] = 1 + arfcns[0]; + return 0; + } + + /* Now do the processing */ + split_at = range_enc_find_index(range, arfcns, size); + + /* we now know where to split */ + out[index] = 1 + arfcns[split_at]; + + /* calculate the work that needs to be done for the leafs */ + l_origin = mod(arfcns[split_at] + ((range - 1) / 2) + 1, range); + r_origin = mod(arfcns[split_at] + 1, range); + for (i = 0, l_size = 0, r_size = 0; i < size; ++i) { + if (mod(arfcns[i] - l_origin, range) < range / 2) + arfcns_left[l_size++] = mod(arfcns[i] - l_origin, range); + if (mod(arfcns[i] - r_origin, range) < range / 2) + arfcns_right[r_size++] = mod(arfcns[i] - r_origin, range); + } + + /* + * Now recurse and we need to make this iterative... but as the + * tree is balanced the stack will not be too deep. + */ + range_enc_arfcns(range / 2, arfcns_left, l_size, + out, index + greatest_power_of_2_lesser_or_equal_to(index + 1)); + range_enc_arfcns((range -1 ) / 2, arfcns_right, r_size, + out, index + (2 * greatest_power_of_2_lesser_or_equal_to(index + 1))); + return 0; +} + +/* + * The easiest is to use f0 == arfcns[0]. This means that under certain + * circumstances we can encode less ARFCNs than possible with an optimal f0. + * + * TODO: Solve the optimisation problem and pick f0 so that the max distance + * is the smallest. Taking into account the modulo operation. I think picking + * size/2 will be the optimal arfcn. + */ +/** + * This implements the range determination as described in GSM 04.08 J4. The + * result will be a base frequency f0 and the range to use. + * + * \param[in] arfcns The input frequencies, they must be sorted, lowest number first + * \param[in] size The length of the array + * \param[out] f0 The selected F0 base frequency. It might not be inside the list + */ +int range_enc_determine_range(const int *arfcns, const int size, int *f0) +{ + int max = 0; + + /* + * Go for the easiest. And pick arfcns[0] == f0. + */ + max = arfcns[size - 1] - arfcns[0]; + *f0 = arfcns[0]; + + if (max < 128 && size <= 29) + return ARFCN_RANGE_128; + if (max < 256 && size <= 22) + return ARFCN_RANGE_256; + if (max < 512 && size <= 18) + return ARFCN_RANGE_512; + if (max < 1024 && size <= 17) + return ARFCN_RANGE_1024; + + return ARFCN_RANGE_INVALID; +} + +/* + * The below is easier is to write in four methods than + * to use the max_bits. The encoding is so screwed.. as + * the bits need to be put in place in the wrong order.. + */ +#define HIGH_BITS(w, index, bits, offset) \ + (w[index - 1] >> (bits - offset)) +#define LOW_BITS(w, index, bits, offset) \ + (w[index - 1]) + +static void write_orig_arfcn(uint8_t *chan_list, int f0) +{ + chan_list[0] |= (f0 >> 9) & 1; + chan_list[1] = (f0 >> 1); + chan_list[2] = (f0 & 1) << 7; +} + +int range_enc_range128(uint8_t *chan_list, int f0, int *w) +{ + chan_list[0] = 0x8C; + write_orig_arfcn(chan_list, f0); + + LOGP(DRR, LOGL_ERROR, "Range128 encoding is not implemented.\n"); + return -1; +} + +int range_enc_range256(uint8_t *chan_list, int f0, int *w) +{ + chan_list[0] = 0x8A; + write_orig_arfcn(chan_list, f0); + + LOGP(DRR, LOGL_ERROR, "Range256 encoding is not implemented.\n"); + return -1; +} + +int range_enc_range512(uint8_t *chan_list, int f0, int *w) +{ + struct gsm48_range_512 *range512; + write_orig_arfcn(chan_list, f0); + + range512 = (struct gsm48_range_512 *) &chan_list[0]; + range512->form_id = chan_list[0] = 0x44; + + /* W(1) */ + range512->w1_hi = HIGH_BITS(w, 1, 9, 7); + range512->w1_lo = LOW_BITS (w, 1, 9, 2); + /* W(2) */ + range512->w2_hi = HIGH_BITS(w, 2, 8, 6); + range512->w2_lo = LOW_BITS (w, 2, 8, 2); + /* W(3) */ + range512->w3_hi = HIGH_BITS(w, 3, 8, 6); + range512->w3_lo = LOW_BITS (w, 3, 8, 2); + /* W(4) */ + range512->w4_hi = HIGH_BITS(w, 4, 7, 6); + range512->w4_lo = LOW_BITS (w, 4, 7, 1); + /* W(5) */ + range512->w5 = HIGH_BITS(w, 5, 7, 7); + /* W(6) */ + range512->w6 = HIGH_BITS(w, 6, 7, 7); + /* W(7) */ + range512->w7_hi = HIGH_BITS(w, 7, 7, 1); + range512->w7_lo = LOW_BITS (w, 7, 7, 6); + /* W(8) */ + range512->w8_hi = HIGH_BITS(w, 8, 6, 2); + range512->w8_lo = LOW_BITS (w, 8, 6, 4); + /* W(9) */ + range512->w9_hi = HIGH_BITS(w, 9, 6, 4); + range512->w9_lo = LOW_BITS(w, 9, 6, 2); + /* W(10) */ + range512->w10 = HIGH_BITS(w, 10, 6, 6); + /* W(11) */ + range512->w11 = HIGH_BITS(w, 11, 6, 6); + /* W(12) */ + range512->w12_hi = HIGH_BITS(w, 12, 6, 2); + range512->w12_lo = LOW_BITS (w, 12, 6, 4); + /* W(13) */ + range512->w13_hi = HIGH_BITS(w, 13, 6, 4); + range512->w13_lo = LOW_BITS(w, 13, 6, 2); + /* W(14) */ + range512->w14 = HIGH_BITS(w, 14, 6, 6); + /* W(15) */ + range512->w15 = HIGH_BITS(w, 15, 6, 6); + /* W(16) */ + range512->w16_hi = HIGH_BITS(w, 16, 5, 2); + range512->w16_lo = HIGH_BITS(w, 16, 5, 3); + /* W(17) */ + range512->w17 = HIGH_BITS(w, 17, 5, 5); + + return 0; +} + +int range_enc_range1024(uint8_t *chan_list, int f0, int f0_included, int *w) +{ + chan_list[0] = 0x80 | (f0_included << 2); + + LOGP(DRR, LOGL_ERROR, "Range1024 encoding is not implemented.\n"); + return -1; +} + +int range_enc_filter_arfcns(const int range, int *arfcns, + const int size, const int f0, int *f0_included) +{ + int i, j = 0; + *f0_included = 0; + + if (range == ARFCN_RANGE_1024) { + for (i = 0; i < size; ++i) { + if (arfcns[i] == f0) { + *f0_included = 1; + continue; + } + + /* copy and subtract */ + arfcns[j++] = mod(arfcns[i] - 1, 1024); + } + } else { + for (i = 0; i < size; ++i) { + /* + * Appendix J.4 says the following: + * All frequencies except F(0), minus F(0) + 1. + * I assume we need to exclude it here. + */ + if (arfcns[i] == f0) + continue; + + arfcns[j++] = mod(arfcns[i] - (f0 + 1), 1024); + } + } + + return j; +} diff --git a/openbsc/src/libbsc/system_information.c b/openbsc/src/libbsc/system_information.c index 08c4fd18a..702924135 100644 --- a/openbsc/src/libbsc/system_information.c +++ b/openbsc/src/libbsc/system_information.c @@ -2,6 +2,7 @@ * 3GPP TS 04.08 version 7.21.0 Release 1998 / ETSI TS 100 940 V7.21.0 */ /* (C) 2008-2010 by Harald Welte <laforge@gnumonks.org> + * (C) 2012 Holger Hans Peter Freyther * * All Rights Reserved * @@ -34,6 +35,7 @@ #include <openbsc/gsm_data.h> #include <openbsc/abis_rsl.h> #include <openbsc/rest_octets.h> +#include <openbsc/arfcn_range_encode.h> /* Frequency Lists as per TS 04.08 10.5.2.13 */ @@ -88,11 +90,105 @@ static int freq_list_bmrel_set_arfcn(uint8_t *chan_list, unsigned int arfcn) return 0; } +/* generate a variable bitmap */ +static int enc_freq_lst_var_bitmap(uint8_t *chan_list, + struct bitvec *bv, const struct gsm_bts *bts, + int bis, int ter, int min, int pgsm) +{ + int i; + + /* set it to 'Variable bitmap format' */ + chan_list[0] = 0x8e; + + chan_list[0] |= (min >> 9) & 1; + chan_list[1] = (min >> 1); + chan_list[2] = (min & 1) << 7; + + for (i = 0; i < bv->data_len*8; i++) { + /* see notes in bitvec2freq_list */ + if (bitvec_get_bit_pos(bv, i) + && ((!bis && !ter && gsm_arfcn2band(i) == bts->band) + || (bis && pgsm && gsm_arfcn2band(i) == bts->band && (i < 1 || i > 124)) + || (ter && gsm_arfcn2band(i) != bts->band))) { + int rc = freq_list_bmrel_set_arfcn(chan_list, i); + if (rc < 0) + return rc; + } + } + + return 0; +} + +/* generate a frequency list with the range 512 format */ +static int enc_freq_lst_range(uint8_t *chan_list, + struct bitvec *bv, const struct gsm_bts *bts, + int bis, int ter, int pgsm) +{ + int arfcns[RANGE_ENC_MAX_ARFCNS]; + int w[RANGE_ENC_MAX_ARFCNS]; + int f0_included = 0; + int arfcns_used = 0; + int i, rc, range, f0; + + /* + * Select ARFCNs according to the rules in bitvec2freq_list + */ + for (i = 0; i < bv->data_len * 8; ++i) { + /* More ARFCNs than the maximum */ + if (arfcns_used > ARRAY_SIZE(arfcns)) + return -1; + /* Check if we can select it? */ + if (bitvec_get_bit_pos(bv, i) + && ((!bis && !ter && gsm_arfcn2band(i) == bts->band) + || (bis && pgsm && gsm_arfcn2band(i) == bts->band && (i < 1 || i > 124)) + || (ter && gsm_arfcn2band(i) != bts->band))) { + arfcns[arfcns_used++] = i; + } + } + + /* + * Check if the given list of ARFCNs can be encoded. + */ + range = range_enc_determine_range(arfcns, arfcns_used, &f0); + if (range == ARFCN_RANGE_INVALID) + return -2; + + /* + * Manipulate the ARFCN list according to the rules in J4 depending + * on the selected range. + */ + arfcns_used = range_enc_filter_arfcns(range, arfcns, arfcns_used, + f0, &f0_included); + + memset(w, 0, sizeof(w)); + rc = range_enc_arfcns(range, arfcns, arfcns_used, w, 0); + if (rc != 0) + return -3; + + /* Select the range and the amount of bits needed */ + switch (range) { + case ARFCN_RANGE_128: + return range_enc_range128(chan_list, f0, w); + break; + case ARFCN_RANGE_256: + return range_enc_range256(chan_list, f0, w); + break; + case ARFCN_RANGE_512: + return range_enc_range512(chan_list, f0, w); + break; + case ARFCN_RANGE_1024: + return range_enc_range1024(chan_list, f0, f0_included, w); + break; + default: + return -4; + }; +} + /* generate a cell channel list as per Section 10.5.2.1b of 04.08 */ static int bitvec2freq_list(uint8_t *chan_list, struct bitvec *bv, const struct gsm_bts *bts, int bis, int ter) { - int i, rc, min = -1, max = -1, pgsm = 0; + int i, rc, min = -1, max = -1, pgsm = 0, arfcns = 0; memset(chan_list, 0, 16); @@ -114,9 +210,6 @@ static int bitvec2freq_list(uint8_t *chan_list, struct bitvec *bv, return 0; } - /* We currently only support the 'Variable bitmap format' */ - chan_list[0] = 0x8e; - for (i = 0; i < bv->data_len*8; i++) { /* in case of SI2 or SI5 allow all neighbours in same band * in case of SI*bis, allow neighbours in same band ouside pgsm @@ -126,6 +219,9 @@ static int bitvec2freq_list(uint8_t *chan_list, struct bitvec *bv, && ((!bis && !ter && gsm_arfcn2band(i) == bts->band) || (bis && pgsm && gsm_arfcn2band(i) == bts->band && (i < 1 || i > 124)) || (ter && gsm_arfcn2band(i) != bts->band))) { + /* count the arfcns we want to carry */ + arfcns += 1; + /* 955..1023 < 0..885 */ if (min < 0) min = i; @@ -152,29 +248,19 @@ static int bitvec2freq_list(uint8_t *chan_list, struct bitvec *bv, return 0; } - if (((max - min) & 1023) > 111) { - LOGP(DRR, LOGL_ERROR, "min_arfcn=%u, max_arfcn=%u, " - "distance > 111\n", min, max); - return -EINVAL; - } - - chan_list[0] |= (min >> 9) & 1; - chan_list[1] = (min >> 1); - chan_list[2] = (min & 1) << 7; + /* Now find the best encoding */ + if (((max - min) & 1023) <= 111) + return enc_freq_lst_var_bitmap(chan_list, bv, bts, bis, + ter, min, pgsm); - for (i = 0; i < bv->data_len*8; i++) { - /* see notes above */ - if (bitvec_get_bit_pos(bv, i) - && ((!bis && !ter && gsm_arfcn2band(i) == bts->band) - || (bis && pgsm && gsm_arfcn2band(i) == bts->band && (i < 1 || i > 124)) - || (ter && gsm_arfcn2band(i) != bts->band))) { - rc = freq_list_bmrel_set_arfcn(chan_list, i); - if (rc < 0) - return rc; - } - } + /* Attempt to do the range encoding */ + rc = enc_freq_lst_range(chan_list, bv, bts, bis, ter, pgsm); + if (rc == 0) + return 0; - return 0; + LOGP(DRR, LOGL_ERROR, "min_arfcn=%u, max_arfcn=%u, arfcns=%d " + "can not generate ARFCN list", min, max, arfcns); + return -EINVAL; } /* generate a cell channel list as per Section 10.5.2.1b of 04.08 */ |