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lchan: Release the lchan more quickly, align with GSM 04.08 

* Release all channels with SAPI > 0 with the "local end release"
  (as of NOTE 1 of GSM 04.08).
* No need to wait for all SAPIs to be torn down and the normal
  REL_IND/REL_CONF will call rsl_handle_release and the channel
  should be released.
* Update the documentation
This commit is contained in:
Holger Hans Peter Freyther 2011-12-27 22:24:17 +01:00
parent 960c4044e6
commit 8582535c82
5 changed files with 54 additions and 62 deletions
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19
openbsc/doc/channel_release.txt
View File

@ -56,21 +56,20 @@ bsc_api.c:gsm0808_clear
* Release the primary lchan with normal release, SACH deactivate
chan_alloc.c:lchan_release(chan, sacch_deactivate, reason)
* Start release procedure. It is working in steps with callbacks
coming from the abis_rsl.c code.
* Release all SAPI's > 0, wait for them to be released
* Send SACH Deactivate on SAPI=0
* Finally Release the channel
* Start the release procedure. It is working in steps with callbacks
coming from the abis_rsl.c code.
* Release all SAPI's > 0 as local end (The BTS should send a
REL_CONF a message)
* Send SACH Deactivate on SAPI=0 if required.
* It should start T3109 but it does not.
* abis_rsl.c schedules the RSL_MT_RF_CHAN_REL once all SAPI's are
released and after T3111 has timed out or there is an error.
RX of RELease INDication:
* Calls internal rsl_handle_release which might release the RF.
* Informs chan_alloc.c about the release with
rsl_lchan_rll_release.
RX of RELease CONFimem:
RX of RELease CONFirmation:
* Calls internal rsl_handle_release which might release the RF.
* Informs chan_alloc.c about the release with
rsl_lchan_rll_release.
* RX of RF_CHAN_REL_ACK
* call lchan_free()

5
openbsc/include/openbsc/abis_rsl.h
View File

@ -74,7 +74,6 @@ int rsl_lchan_set_state(struct gsm_lchan *lchan, int);
/* to be provided by external code */
int rsl_deact_sacch(struct gsm_lchan *lchan);
int rsl_lchan_rll_release(struct gsm_lchan *lchan, uint8_t link_id);
/* BCCH related code */
int rsl_ccch_conf_to_bs_cc_chans(int ccch_conf);
@ -97,5 +96,9 @@ int rsl_nokia_si_end(struct gsm_bts_trx *trx);
/* required for Nokia BTS power control */
int rsl_bs_power_control(struct gsm_bts_trx *trx, uint8_t channel, uint8_t reduction);
int rsl_release_sapis_from(struct gsm_lchan *lchan, int start,
enum rsl_rel_mode release_mode);
#endif /* RSL_MT_H */

3
openbsc/include/openbsc/gsm_data_shared.h
View File

@ -196,9 +196,6 @@ struct gsm_lchan {
uint8_t sapis[8];
int sacch_deact;
/* Release handling */
enum rsl_rel_mode release_mode;
struct {
uint32_t bound_ip;
uint32_t connect_ip;

30
openbsc/src/libbsc/abis_rsl.c
View File

@ -2,6 +2,7 @@
* 3GPP TS 08.58 version 8.6.0 Release 1999 / ETSI TS 100 596 V8.6.0 */
/* (C) 2008-2010 by Harald Welte <laforge@gnumonks.org>
* (C) 2012 by Holger Hans Peter Freyther
*
* All Rights Reserved
*
@ -1581,7 +1582,6 @@ static int abis_rsl_rx_rll(struct msgb *msg)
rll_indication(msg->lchan, rllh->link_id,
BSC_RLLR_IND_REL_IND);
rsl_handle_release(msg->lchan);
rsl_lchan_rll_release(msg->lchan, rllh->link_id);
break;
case RSL_MT_REL_CONF:
/* BTS informs us of having received UA from MS,
@ -1589,7 +1589,6 @@ static int abis_rsl_rx_rll(struct msgb *msg)
DEBUGPC(DRLL, "RELEASE CONFIRMATION\n");
msg->lchan->sapis[rllh->link_id & 0x7] = LCHAN_SAPI_UNUSED;
rsl_handle_release(msg->lchan);
rsl_lchan_rll_release(msg->lchan, rllh->link_id);
break;
case RSL_MT_ERROR_IND:
rc = rsl_rx_rll_err_ind(msg);
@ -2058,3 +2057,30 @@ int rsl_bs_power_control(struct gsm_bts_trx *trx, uint8_t channel, uint8_t reduc
return abis_rsl_sendmsg(msg);
}
/**
* Release all allocated SAPIs starting from @param start and
* release them with the given release mode. Once the release
* confirmation arrives it will be attempted to release the
* the RF channel.
*/
int rsl_release_sapis_from(struct gsm_lchan *lchan, int start,
enum rsl_rel_mode release_mode)
{
int no_sapi = 1;
int sapi;
for (sapi = start; sapi < ARRAY_SIZE(lchan->sapis); ++sapi) {
uint8_t link_id;
if (lchan->sapis[sapi] == LCHAN_SAPI_UNUSED)
continue;
link_id = sapi;
if (lchan->type == GSM_LCHAN_TCH_F || lchan->type == GSM_LCHAN_TCH_H)
link_id |= 0x40;
rsl_release_request(lchan, link_id, release_mode);
no_sapi = 0;
}
return no_sapi;
}

59
openbsc/src/libbsc/chan_alloc.c
View File

@ -345,8 +345,6 @@ void lchan_free(struct gsm_lchan *lchan)
}
lchan->sacch_deact = 0;
lchan->release_mode = RSL_REL_NORMAL;
/* FIXME: ts_free() the timeslot, if we're the last logical
* channel using it */
}
@ -376,51 +374,22 @@ void lchan_reset(struct gsm_lchan *lchan)
}
}
/* release the next allocated SAPI or return 0 */
static int _lchan_release_next_sapi(struct gsm_lchan *lchan)
{
int sapi;
for (sapi = 1; sapi < ARRAY_SIZE(lchan->sapis); ++sapi) {
uint8_t link_id;
if (lchan->sapis[sapi] == LCHAN_SAPI_UNUSED)
continue;
link_id = sapi;
if (lchan->type == GSM_LCHAN_TCH_F || lchan->type == GSM_LCHAN_TCH_H)
link_id |= 0x40;
rsl_release_request(lchan, link_id, RSL_REL_LOCAL_END);
return 0;
}
return 1;
}
/* Drive the release process of the lchan */
static void _lchan_handle_release(struct gsm_lchan *lchan)
static void _lchan_handle_release(struct gsm_lchan *lchan,
int sach_deact, int mode)
{
/* Ask for SAPI != 0 to be freed first and stop if we need to wait */
if (_lchan_release_next_sapi(lchan) == 0)
return;
/* Release all SAPIs on the local end and continue */
rsl_release_sapis_from(lchan, 1, RSL_REL_LOCAL_END);
if (lchan->sacch_deact) {
/*
* Shall we send a RR Release, start T3109 and wait for the
* release indication from the BTS or just take it down (e.g.
* on assignment requests)
*/
if (sach_deact)
gsm48_send_rr_release(lchan);
return;
}
rsl_release_request(lchan, 0, lchan->release_mode);
rsl_lchan_set_state(lchan, LCHAN_S_REL_REQ);
}
/* called from abis rsl */
int rsl_lchan_rll_release(struct gsm_lchan *lchan, uint8_t link_id)
{
if (lchan->state != LCHAN_S_REL_REQ)
return -1;
if ((link_id & 0x7) != 0)
_lchan_handle_release(lchan);
return 0;
else
rsl_release_request(lchan, 0, mode);
}
/* Consider releasing the channel now */
@ -430,9 +399,7 @@ int lchan_release(struct gsm_lchan *lchan, int sacch_deact, enum rsl_rel_mode mo
rsl_lchan_set_state(lchan, LCHAN_S_REL_REQ);
lchan->conn = NULL;
lchan->release_mode = mode;
lchan->sacch_deact = sacch_deact;
_lchan_handle_release(lchan);
_lchan_handle_release(lchan, sacch_deact, mode);
return 1;
}