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clear GPRS indicator in SI3 while PCU is disconnected 

osmo-bts cannot provide GPRS service while osmo-pcu is not connected.
The BSC has no knowledge of the PCU connection state. Prevent MSs
from trying to register for GPRS while the PCU is disconnected by
erasing the GPRS Indicator in SI3.

Change-Id: I1a6f5c636c0fe098ee31c280d4572a3f8122b44b
Depends: I690cf308311f910005a325d50f5d5d825678d2b2 (libosmocore.git)
Depends: I08e0ca9a8d13c7aa40b9d90f34f0e13adb87d4e0 (libosmocore.git)
Depends: I8b1ee2405f6338507e9dfb5f1f437c4c2db2e330 (libosmocore.git)
Related: OS#3075
This commit is contained in:
Harald Welte 2019-05-28 18:06:21 +02:00
parent 347fea69a0
commit 1e96e31c10
5 changed files with 63 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
include/osmo-bts/bts.h
View File

@ -48,6 +48,7 @@ int bts_ccch_copy_msg(struct gsm_bts *bts, uint8_t *out_buf, struct gsm_time *gt
int is_ag_res);
uint8_t *bts_sysinfo_get(struct gsm_bts *bts, const struct gsm_time *g_time);
void regenerate_si3_restoctets(struct gsm_bts *bts);
uint8_t *lchan_sacch_get(struct gsm_lchan *lchan);
int lchan_init_lapdm(struct gsm_lchan *lchan);

5
include/osmo-bts/gsm_data_shared.h
View File

@ -15,6 +15,7 @@
#include <osmocom/gsm/rxlev_stat.h>
#include <osmocom/gsm/sysinfo.h>
#include <osmocom/gsm/meas_rep.h>
#include <osmocom/gsm/gsm48_rest_octets.h>
#include <osmocom/gsm/protocol/gsm_04_08.h>
#include <osmocom/gsm/protocol/gsm_08_58.h>
#include <osmocom/gsm/protocol/gsm_12_21.h>
@ -620,6 +621,10 @@ struct gsm_bts {
/* offsets used while generating SI2quater */
size_t e_offset;
size_t u_offset;
/* decoded SI3 rest octets - *unmodified* as received from BSC */
struct osmo_gsm48_si_ro_info si3_ro_decoded;
/* is SI3 GPRS Indicator currently disabled due to lack of PCU connection? */
bool si3_gprs_ind_disabled;
/* ip.accesss Unit ID's have Site/BTS/TRX layout */
union {

8
src/common/pcu_sock.c
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@ -1,6 +1,6 @@
/* pcu_sock.c: Connect from PCU via unix domain socket */
/* (C) 2008-2010 by Harald Welte <laforge@gnumonks.org>
/* (C) 2008-2019 by Harald Welte <laforge@gnumonks.org>
* (C) 2009-2012 by Andreas Eversberg <jolly@eversberg.eu>
* (C) 2012 by Holger Hans Peter Freyther
* All Rights Reserved
@ -598,6 +598,9 @@ static int pcu_rx_txt_ind(struct gsm_bts *bts,
oml_tx_failure_event_rep(&bts->gprs.cell.mo, NM_SEVER_CEASED, OSMO_EVT_PCU_VERS, txt->text);
osmo_strlcpy(bts->pcu_version, txt->text, MAX_VERSION_LENGTH);
/* patch SI3 to advertise GPRS, *if* the SI3 sent by BSC said so */
regenerate_si3_restoctets(bts);
if (GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_13))
return pcu_tx_si13(bts, true);
@ -741,6 +744,9 @@ static void pcu_sock_close(struct pcu_sock_state *state)
bfd->fd = -1;
osmo_fd_unregister(bfd);
/* patch SI3 to remove GPRS indicator */
regenerate_si3_restoctets(bts);
/* re-enable the generation of ACCEPT for new connections */
state->listen_bfd.when |= BSC_FD_READ;

22
src/common/rsl.c
View File

@ -1,7 +1,7 @@
/* GSM TS 08.58 RSL, BTS Side */
/* (C) 2011 by Andreas Eversberg <jolly@eversberg.eu>
* (C) 2011-2017 by Harald Welte <laforge@gnumonks.org>
* (C) 2011-2019 by Harald Welte <laforge@gnumonks.org>
*
* All Rights Reserved
*
@ -360,12 +360,18 @@ static int rsl_rx_bcch_info(struct gsm_bts_trx *trx, struct msgb *msg)
bts->si_valid |= (1 << osmo_si);
if (SYSINFO_TYPE_3 == osmo_si && trx->nr == 0 &&
num_agch(trx, "RSL") != 1) {
lchan_deactivate(&trx->bts->c0->ts[0].lchan[CCCH_LCHAN]);
/* will be reactivated by sapi_deactivate_cb() */
trx->bts->c0->ts[0].lchan[CCCH_LCHAN].rel_act_kind =
LCHAN_REL_ACT_REACT;
if (SYSINFO_TYPE_3 == osmo_si) {
if (trx->nr == 0 && num_agch(trx, "RSL") != 1) {
lchan_deactivate(&trx->bts->c0->ts[0].lchan[CCCH_LCHAN]);
/* will be reactivated by sapi_deactivate_cb() */
trx->bts->c0->ts[0].lchan[CCCH_LCHAN].rel_act_kind =
LCHAN_REL_ACT_REACT;
}
/* decode original SI3 Rest Octets as sent by BSC */
osmo_gsm48_rest_octets_si3_decode(&bts->si3_ro_decoded, GSM_BTS_SI(bts, osmo_si));
/* patch out GPRS indicator from binary if PCU is not connected; will be enabled
* after PCU connects */
regenerate_si3_restoctets(bts);
}
if (SYSINFO_TYPE_13 == osmo_si)
@ -387,6 +393,8 @@ static int rsl_rx_bcch_info(struct gsm_bts_trx *trx, struct msgb *msg)
get_value_string(osmo_sitype_strs, osmo_si));
if (SYSINFO_TYPE_13 == osmo_si)
pcu_tx_si13(trx->bts, false);
if (SYSINFO_TYPE_3 == osmo_si)
memset(&bts->si3_ro_decoded, 0, sizeof(bts->si3_ro_decoded));
}
osmo_signal_dispatch(SS_GLOBAL, S_NEW_SYSINFO, bts);

36
src/common/sysinfo.c
View File

@ -1,4 +1,4 @@
/* (C) 2011 by Harald Welte <laforge@gnumonks.org>
/* (C) 2011-2019 by Harald Welte <laforge@gnumonks.org>
*
* All Rights Reserved
*
@ -24,6 +24,7 @@
#include <osmo-bts/logging.h>
#include <osmo-bts/gsm_data.h>
#include <osmo-bts/pcu_if.h>
/* properly increment SI2q index and return SI2q data for scheduling */
static inline uint8_t *get_si2q_inc_index(struct gsm_bts *bts)
@ -175,3 +176,36 @@ uint8_t *lchan_sacch_get(struct gsm_lchan *lchan)
LOGPLCHAN(lchan, DL1P, LOGL_NOTICE, "SACCH no SI available\n");
return NULL;
}
/* re-generate SI3 restoctets with GPRS indicator depending on the PCU socket connection state */
void regenerate_si3_restoctets(struct gsm_bts *bts)
{
uint8_t *si3_buf = GSM_BTS_SI(bts, SYSINFO_TYPE_3);
size_t si3_size = offsetof(struct gsm48_system_information_type_3, rest_octets);
struct osmo_gsm48_si_ro_info si3ro_tmp;
/* If BSC has never set SI3, there's nothing to patch */
if (!GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_3))
return;
/* If SI3 from BSC doesn't have a GPRS indicator, we won't have anything to patch */
if (!bts->si3_ro_decoded.gprs_ind.present)
return;
/* Create a temporary copy and patch that, if no PCU is around */
si3ro_tmp = bts->si3_ro_decoded;
if (!pcu_connected()) {
if (!bts->si3_gprs_ind_disabled)
LOGP(DPCU, LOGL_NOTICE, "Disabling GPRS Indicator in SI3 (No PCU connected)\n");
bts->si3_gprs_ind_disabled = true;
si3ro_tmp.gprs_ind.present = 0;
} else {
if (bts->si3_gprs_ind_disabled)
LOGP(DPCU, LOGL_NOTICE, "Enabling GPRS Indicator in SI3 (PCU connected)\n");
bts->si3_gprs_ind_disabled = false;
si3ro_tmp.gprs_ind.present = 1; /* is a no-op as we copy from bts->si3_ro_decoded */
}
/* re-generate the binary SI3 rest octets */
osmo_gsm48_rest_octets_si3_encode(si3_buf + si3_size, &si3ro_tmp);
}