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-rw-r--r--src/gsm/gsm_utils.c465
1 files changed, 465 insertions, 0 deletions
diff --git a/src/gsm/gsm_utils.c b/src/gsm/gsm_utils.c
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+/*
+ * (C) 2008 by Daniel Willmann <daniel@totalueberwachung.de>
+ * (C) 2009 by Holger Hans Peter Freyther <zecke@selfish.org>
+ * (C) 2009-2010 by Harald Welte <laforge@gnumonks.org>
+ * (C) 2010 by Nico Golde <nico@ngolde.de>
+ *
+ * All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ */
+
+//#include <openbsc/gsm_data.h>
+#include <osmocore/utils.h>
+#include <osmocore/gsm_utils.h>
+
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <stdio.h>
+#include <errno.h>
+#include <ctype.h>
+
+#include "../config.h"
+
+/* ETSI GSM 03.38 6.2.1 and 6.2.1.1 default alphabet
+ * Greek symbols at hex positions 0x10 and 0x12-0x1a
+ * left out as they can't be handled with a char and
+ * since most phones don't display or write these
+ * characters this would only needlessly make the code
+ * more complex
+*/
+static unsigned char gsm_7bit_alphabet[] = {
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x0a, 0xff, 0xff, 0x0d, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0x20, 0x21, 0x22, 0x23, 0x02, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b, 0x2c,
+ 0x2d, 0x2e, 0x2f, 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3b,
+ 0x3c, 0x3d, 0x3e, 0x3f, 0x00, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4a,
+ 0x4b, 0x4c, 0x4d, 0x4e, 0x4f, 0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59,
+ 0x5a, 0x3c, 0x2f, 0x3e, 0x14, 0x11, 0xff, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68,
+ 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77,
+ 0x78, 0x79, 0x7a, 0x28, 0x40, 0x29, 0x3d, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0x0c, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x5e, 0xff, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x40, 0xff, 0x01, 0xff,
+ 0x03, 0xff, 0x7b, 0x7d, 0xff, 0xff, 0xff, 0xff, 0xff, 0x5c, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x5b, 0x7e, 0x5d, 0xff, 0x7c, 0xff, 0xff, 0xff,
+ 0xff, 0x5b, 0x0e, 0x1c, 0x09, 0xff, 0x1f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x5d,
+ 0xff, 0xff, 0xff, 0xff, 0x5c, 0xff, 0x0b, 0xff, 0xff, 0xff, 0x5e, 0xff, 0xff, 0x1e, 0x7f,
+ 0xff, 0xff, 0xff, 0x7b, 0x0f, 0x1d, 0xff, 0x04, 0x05, 0xff, 0xff, 0x07, 0xff, 0xff, 0xff,
+ 0xff, 0x7d, 0x08, 0xff, 0xff, 0xff, 0x7c, 0xff, 0x0c, 0x06, 0xff, 0xff, 0x7e, 0xff, 0xff
+};
+
+/* GSM 03.38 6.2.1 Character lookup for decoding */
+static int gsm_septet_lookup(uint8_t ch)
+{
+ int i = 0;
+ for(; i < sizeof(gsm_7bit_alphabet); i++){
+ if(gsm_7bit_alphabet[i] == ch)
+ return i;
+ }
+ return -1;
+}
+
+/* GSM 03.38 6.2.1 Character unpacking */
+int gsm_7bit_decode(char *text, const uint8_t *user_data, uint8_t length)
+{
+ int i = 0;
+ int l = 0;
+ int septet_l = (length * 8) / 7;
+ uint8_t *rtext = calloc(septet_l, sizeof(uint8_t));
+ uint8_t tmp;
+
+ /* FIXME: We need to account for user data headers here */
+ i += l;
+ for (; i < septet_l; i++){
+ rtext[i] =
+ ((user_data[(i * 7 + 7) >> 3] <<
+ (7 - ((i * 7 + 7) & 7))) |
+ (user_data[(i * 7) >> 3] >>
+ ((i * 7) & 7))) & 0x7f;
+ }
+
+ for(i = 0; i < septet_l; i++){
+ /* this is an extension character */
+ if(rtext[i] == 0x1b && i + 1 < length){
+ tmp = rtext[i+1];
+ *(text++) = gsm_7bit_alphabet[0x7f + tmp];
+ i++;
+ continue;
+ }
+
+ *(text++) = gsm_septet_lookup(rtext[i]);
+ }
+
+ *text = '\0';
+ free(rtext);
+
+ return i;
+}
+
+/* GSM 03.38 6.2.1 Prepare character packing */
+static int gsm_septet_encode(uint8_t *result, const char *data)
+{
+ int i, y = 0;
+ uint8_t ch;
+ for(i = 0; i < strlen(data); i++){
+ ch = data[i];
+ switch(ch){
+ /* fall-through for extension characters */
+ case 0x0c:
+ case 0x5e:
+ case 0x7b:
+ case 0x7d:
+ case 0x5c:
+ case 0x5b:
+ case 0x7e:
+ case 0x5d:
+ case 0x7c:
+ result[y++] = 0x1b;
+ default:
+ result[y] = gsm_7bit_alphabet[ch];
+ break;
+ }
+ y++;
+ }
+
+ return y;
+}
+
+/* GSM 03.38 6.2.1 Character packing */
+int gsm_7bit_encode(uint8_t *result, const char *data)
+{
+ int i,y,z = 0;
+ /* prepare for the worst case, every character expanding to two bytes */
+ uint8_t *rdata = calloc(strlen(data) * 2, sizeof(uint8_t));
+ uint8_t cb, nb;
+ int shift = 0;
+
+ y = gsm_septet_encode(rdata, data);
+
+ for(i = 0; i < y; i++) {
+ if(shift == 7 && i + 1 < y){
+ shift = 0;
+ continue;
+ }
+
+ cb = (rdata[i] & 0x7f) >> shift;
+ if(i + 1 < y){
+ nb = (rdata[i + 1] & 0x7f) << (7 - shift);
+ cb = cb | nb;
+ }
+
+ result[z++] = cb;
+
+ shift++;
+ }
+
+ free(rdata);
+ return z;
+}
+
+/* determine power control level for given dBm value, as indicated
+ * by the tables in chapter 4.1.1 of GSM TS 05.05 */
+int ms_pwr_ctl_lvl(enum gsm_band band, unsigned int dbm)
+{
+ switch (band) {
+ case GSM_BAND_450:
+ case GSM_BAND_480:
+ case GSM_BAND_750:
+ case GSM_BAND_900:
+ case GSM_BAND_810:
+ case GSM_BAND_850:
+ if (dbm >= 39)
+ return 0;
+ else if (dbm < 5)
+ return 19;
+ else {
+ /* we are guaranteed to have (5 <= dbm < 39) */
+ return 2 + ((39 - dbm) / 2);
+ }
+ break;
+ case GSM_BAND_1800:
+ if (dbm >= 36)
+ return 29;
+ else if (dbm >= 34)
+ return 30;
+ else if (dbm >= 32)
+ return 31;
+ else if (dbm == 31)
+ return 0;
+ else {
+ /* we are guaranteed to have (0 <= dbm < 31) */
+ return (30 - dbm) / 2;
+ }
+ break;
+ case GSM_BAND_1900:
+ if (dbm >= 33)
+ return 30;
+ else if (dbm >= 32)
+ return 31;
+ else if (dbm == 31)
+ return 0;
+ else {
+ /* we are guaranteed to have (0 <= dbm < 31) */
+ return (30 - dbm) / 2;
+ }
+ break;
+ }
+ return -EINVAL;
+}
+
+int ms_pwr_dbm(enum gsm_band band, uint8_t lvl)
+{
+ lvl &= 0x1f;
+
+ switch (band) {
+ case GSM_BAND_450:
+ case GSM_BAND_480:
+ case GSM_BAND_750:
+ case GSM_BAND_900:
+ case GSM_BAND_810:
+ case GSM_BAND_850:
+ if (lvl < 2)
+ return 39;
+ else if (lvl < 20)
+ return 39 - ((lvl - 2) * 2) ;
+ else
+ return 5;
+ break;
+ case GSM_BAND_1800:
+ if (lvl < 16)
+ return 30 - (lvl * 2);
+ else if (lvl < 29)
+ return 0;
+ else
+ return 36 - ((lvl - 29) * 2);
+ break;
+ case GSM_BAND_1900:
+ if (lvl < 16)
+ return 30 - (lvl * 2);
+ else if (lvl < 30)
+ return -EINVAL;
+ else
+ return 33 - (lvl - 30);
+ break;
+ }
+ return -EINVAL;
+}
+
+/* According to TS 08.05 Chapter 8.1.4 */
+int rxlev2dbm(uint8_t rxlev)
+{
+ if (rxlev > 63)
+ rxlev = 63;
+
+ return -110 + rxlev;
+}
+
+/* According to TS 08.05 Chapter 8.1.4 */
+uint8_t dbm2rxlev(int dbm)
+{
+ int rxlev = dbm + 110;
+
+ if (rxlev > 63)
+ rxlev = 63;
+ else if (rxlev < 0)
+ rxlev = 0;
+
+ return rxlev;
+}
+
+const char *gsm_band_name(enum gsm_band band)
+{
+ switch (band) {
+ case GSM_BAND_450:
+ return "GSM450";
+ case GSM_BAND_480:
+ return "GSM480";
+ case GSM_BAND_750:
+ return "GSM750";
+ case GSM_BAND_810:
+ return "GSM810";
+ case GSM_BAND_850:
+ return "GSM850";
+ case GSM_BAND_900:
+ return "GSM900";
+ case GSM_BAND_1800:
+ return "DCS1800";
+ case GSM_BAND_1900:
+ return "PCS1900";
+ }
+ return "invalid";
+}
+
+enum gsm_band gsm_band_parse(const char* mhz)
+{
+ while (*mhz && !isdigit(*mhz))
+ mhz++;
+
+ if (*mhz == '\0')
+ return -EINVAL;
+
+ switch (strtol(mhz, NULL, 10)) {
+ case 450:
+ return GSM_BAND_450;
+ case 480:
+ return GSM_BAND_480;
+ case 750:
+ return GSM_BAND_750;
+ case 810:
+ return GSM_BAND_810;
+ case 850:
+ return GSM_BAND_850;
+ case 900:
+ return GSM_BAND_900;
+ case 1800:
+ return GSM_BAND_1800;
+ case 1900:
+ return GSM_BAND_1900;
+ default:
+ return -EINVAL;
+ }
+}
+
+enum gsm_band gsm_arfcn2band(uint16_t arfcn)
+{
+ int is_pcs = arfcn & ARFCN_PCS;
+
+ arfcn &= ~ARFCN_FLAG_MASK;
+
+ if (is_pcs)
+ return GSM_BAND_1900;
+ else if (arfcn <= 124)
+ return GSM_BAND_900;
+ else if (arfcn >= 955 && arfcn <= 1023)
+ return GSM_BAND_900;
+ else if (arfcn >= 128 && arfcn <= 251)
+ return GSM_BAND_850;
+ else if (arfcn >= 512 && arfcn <= 885)
+ return GSM_BAND_1800;
+ else if (arfcn >= 259 && arfcn <= 293)
+ return GSM_BAND_450;
+ else if (arfcn >= 306 && arfcn <= 340)
+ return GSM_BAND_480;
+ else if (arfcn >= 350 && arfcn <= 425)
+ return GSM_BAND_810;
+ else if (arfcn >= 438 && arfcn <= 511)
+ return GSM_BAND_750;
+ else
+ return GSM_BAND_1800;
+}
+
+/* Convert an ARFCN to the frequency in MHz * 10 */
+uint16_t gsm_arfcn2freq10(uint16_t arfcn, int uplink)
+{
+ uint16_t freq10_ul;
+ uint16_t freq10_dl;
+ int is_pcs = arfcn & ARFCN_PCS;
+
+ arfcn &= ~ARFCN_FLAG_MASK;
+
+ if (is_pcs) {
+ /* DCS 1900 */
+ arfcn &= ~ARFCN_PCS;
+ freq10_ul = 18502 + 2 * (arfcn-512);
+ freq10_dl = freq10_ul + 800;
+ } else if (arfcn <= 124) {
+ /* Primary GSM + ARFCN 0 of E-GSM */
+ freq10_ul = 8900 + 2 * arfcn;
+ freq10_dl = freq10_ul + 450;
+ } else if (arfcn >= 955 && arfcn <= 1023) {
+ /* E-GSM and R-GSM */
+ freq10_ul = 8900 + 2 * (arfcn - 1024);
+ freq10_dl = freq10_ul + 450;
+ } else if (arfcn >= 128 && arfcn <= 251) {
+ /* GSM 850 */
+ freq10_ul = 8242 + 2 * (arfcn - 128);
+ freq10_dl = freq10_ul + 450;
+ } else if (arfcn >= 512 && arfcn <= 885) {
+ /* DCS 1800 */
+ freq10_ul = 17102 + 2 * (arfcn - 512);
+ freq10_dl = freq10_ul + 950;
+ } else if (arfcn >= 259 && arfcn <= 293) {
+ /* GSM 450 */
+ freq10_ul = 4506 + 2 * (arfcn - 259);
+ freq10_dl = freq10_ul + 100;
+ } else if (arfcn >= 306 && arfcn <= 340) {
+ /* GSM 480 */
+ freq10_ul = 4790 + 2 * (arfcn - 306);
+ freq10_dl = freq10_ul + 100;
+ } else if (arfcn >= 350 && arfcn <= 425) {
+ /* GSM 810 */
+ freq10_ul = 8060 + 2 * (arfcn - 350);
+ freq10_dl = freq10_ul + 450;
+ } else if (arfcn >= 438 && arfcn <= 511) {
+ /* GSM 750 */
+ freq10_ul = 7472 + 2 * (arfcn - 438);
+ freq10_dl = freq10_ul + 300;
+ } else
+ return 0xffff;
+
+ if (uplink)
+ return freq10_ul;
+ else
+ return freq10_dl;
+}
+
+void gsm_fn2gsmtime(struct gsm_time *time, uint32_t fn)
+{
+ time->fn = fn;
+ time->t1 = time->fn / (26*51);
+ time->t2 = time->fn % 26;
+ time->t3 = time->fn % 51;
+ time->tc = (time->fn / 51) % 8;
+}
+
+uint32_t gsm_gsmtime2fn(struct gsm_time *time)
+{
+ /* TS 05.02 Chapter 4.3.3 TDMA frame number */
+ return (51 * ((time->t3 - time->t2 + 26) % 26) + time->t3 + (26 * 51 * time->t1));
+}
+
+/* TS 03.03 Chapter 2.6 */
+int gprs_tlli_type(uint32_t tlli)
+{
+ if ((tlli & 0xc0000000) == 0xc0000000)
+ return TLLI_LOCAL;
+ else if ((tlli & 0xc0000000) == 0x80000000)
+ return TLLI_FOREIGN;
+ else if ((tlli & 0xf8000000) == 0x78000000)
+ return TLLI_RANDOM;
+ else if ((tlli & 0xf8000000) == 0x70000000)
+ return TLLI_AUXILIARY;
+
+ return TLLI_RESERVED;
+}
+
+uint32_t gprs_tmsi2tlli(uint32_t p_tmsi, enum gprs_tlli_type type)
+{
+ uint32_t tlli;
+ switch (type) {
+ case TLLI_LOCAL:
+ tlli = p_tmsi | 0xc0000000;
+ break;
+ case TLLI_FOREIGN:
+ tlli = (p_tmsi & 0x3fffffff) | 0x80000000;
+ break;
+ default:
+ tlli = 0;
+ break;
+ }
+ return tlli;
+}