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/*
* ta.cpp timing advance handling
* Copyright (C) 2012 Ivan Klyuchnikov
* Copyright (C) 2012 Andreas Eversberg <jolly@eversberg.eu>
* Copyright (C) 2013 by Holger Hans Peter Freyther
*
* 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include <ta.h>
#include <gprs_rlcmac.h>
extern "C" {
#include <osmocom/core/talloc.h>
}
#include <errno.h>
extern void *tall_pcu_ctx;
/*
* timing advance memory
*/
/* enable to debug timing advance memory */
//#define DEBUG_TA
struct gprs_rlcmac_ta {
struct llist_head list;
uint32_t tlli;
uint8_t ta;
};
TimingAdvance::TimingAdvance()
: m_ta_len(0)
{
INIT_LLIST_HEAD(&m_ta_list);
}
/* remember timing advance of a given TLLI */
int TimingAdvance::remember(uint32_t tlli, uint8_t ta)
{
struct gprs_rlcmac_ta *ta_entry;
/* check for existing entry */
llist_for_each_entry(ta_entry, &m_ta_list, list) {
if (ta_entry->tlli == tlli) {
#ifdef DEBUG_TA
fprintf(stderr, "update %08x %d\n", tlli, ta);
#endif
ta_entry->ta = ta;
/* relink to end of list */
llist_del(&ta_entry->list);
llist_add_tail(&ta_entry->list, &m_ta_list);
return 0;
}
}
#ifdef DEBUG_TA
fprintf(stderr, "remember %08x %d\n", tlli, ta);
#endif
/* if list is full, remove oldest entry */
if (m_ta_len == 30) {
ta_entry = llist_entry(m_ta_list.next,
struct gprs_rlcmac_ta, list);
llist_del(&ta_entry->list);
talloc_free(ta_entry);
m_ta_len--;
}
/* create new TA entry */
ta_entry = talloc_zero(tall_pcu_ctx, struct gprs_rlcmac_ta);
if (!ta_entry)
return -ENOMEM;
ta_entry->tlli = tlli;
ta_entry->ta = ta;
llist_add_tail(&ta_entry->list, &m_ta_list);
m_ta_len++;
return 0;
}
int TimingAdvance::recall(uint32_t tlli)
{
struct gprs_rlcmac_ta *ta_entry;
uint8_t ta;
llist_for_each_entry(ta_entry, &m_ta_list, list) {
if (ta_entry->tlli == tlli) {
ta = ta_entry->ta;
#ifdef DEBUG_TA
fprintf(stderr, "recall %08x %d\n", tlli, ta);
#endif
return ta;
}
}
#ifdef DEBUG_TA
fprintf(stderr, "no entry for %08x\n", tlli);
#endif
return -EINVAL;
}
int TimingAdvance::flush()
{
struct gprs_rlcmac_ta *ta_entry;
int count = 0;
while (!llist_empty(&m_ta_list)) {
ta_entry = llist_entry(m_ta_list.next,
struct gprs_rlcmac_ta, list);
#ifdef DEBUG_TA
fprintf(stderr, "flush entry %08x %d\n", ta_entry->tlli,
ta_entry->ta);
#endif
llist_del(&ta_entry->list);
talloc_free(ta_entry);
count++;
}
m_ta_len = 0;
return count;
}
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