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authorHolger Hans Peter Freyther <zecke@selfish.org>2010-07-29 17:09:36 +0800
committerHolger Hans Peter Freyther <zecke@selfish.org>2010-07-31 04:09:38 +0800
commit4b85a323600a623afc7728f9d3433e4745765a7c (patch)
tree8c4110976d5024ef1275ce930ef661bcbc0ac940 /openbsc/src
parentaeb45f518675db74135ac5067c15292ba6d4db31 (diff)
chan_alloc: Change Channel Release to release SAPIs, then the channel
Currently every SAPI release indication will trigger the channel. It was possible that we had SAPI=3 and SAPI=0 allocated and we tried to release the channel by sending a RF Channel Release, the BTS answered with a RF Channel Release ACK but also sent the SAPI Release Indication which triggered a channel release here. So it was possible that we would have released a newly allocated channel because of the SAPI release of the old connection. This code now works by releasing all SAPIs from highest to lowest, then sending a SACH Deactivate and finally releasing the channel. This approach is in use on the on-waves/bsc-master.
Diffstat (limited to 'openbsc/src')
-rw-r--r--openbsc/src/abis_rsl.c18
-rw-r--r--openbsc/src/chan_alloc.c59
2 files changed, 68 insertions, 9 deletions
diff --git a/openbsc/src/abis_rsl.c b/openbsc/src/abis_rsl.c
index 7b19d7f43..706842225 100644
--- a/openbsc/src/abis_rsl.c
+++ b/openbsc/src/abis_rsl.c
@@ -1356,11 +1356,21 @@ static int rsl_rx_rll_err_ind(struct msgb *msg)
static void rsl_handle_release(struct gsm_lchan *lchan)
{
+ int sapi;
struct gsm_bts *bts;
+
+ /* maybe we have only brought down one RLL */
if (lchan->state != LCHAN_S_REL_REQ)
- LOGP(DRSL, LOGL_ERROR, "RF release on %s but state %s\n",
- gsm_lchan_name(lchan),
- gsm_lchans_name(lchan->state));
+ return;
+
+ for (sapi = 0; sapi < ARRAY_SIZE(lchan->sapis); ++sapi) {
+ if (lchan->sapis[sapi] == LCHAN_SAPI_UNUSED)
+ continue;
+ LOGP(DRSL, LOGL_NOTICE, "%s waiting for SAPI=%d to be released.\n",
+ gsm_lchan_name(lchan), sapi);
+ return;
+ }
+
/* wait a bit to send the RF Channel Release */
@@ -1422,6 +1432,7 @@ 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,
@@ -1429,6 +1440,7 @@ 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);
diff --git a/openbsc/src/chan_alloc.c b/openbsc/src/chan_alloc.c
index b061fc798..5325dc08a 100644
--- a/openbsc/src/chan_alloc.c
+++ b/openbsc/src/chan_alloc.c
@@ -328,6 +328,9 @@ void lchan_free(struct gsm_lchan *lchan)
lchan->conn = NULL;
}
+ lchan->sach_deact = 0;
+ lchan->release_reason = 0;
+
/* FIXME: ts_free() the timeslot, if we're the last logical
* channel using it */
}
@@ -352,18 +355,62 @@ void lchan_reset(struct gsm_lchan *lchan)
lchan->state = LCHAN_S_NONE;
}
+/* release the next allocated SAPI or return 0 */
+static int _lchan_release_next_sapi(struct gsm_lchan *lchan)
+{
+ int sapi;
-/* Consider releasing the channel now */
-int lchan_release(struct gsm_lchan *lchan, int sach_deact, int reason)
+ for (sapi = 1; sapi < ARRAY_SIZE(lchan->sapis); ++sapi) {
+ u_int8_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, lchan->release_reason);
+ return 0;
+ }
+
+ return 1;
+}
+
+/* Drive the release process of the lchan */
+static void _lchan_handle_release(struct gsm_lchan *lchan)
{
- /* Assume we have GSM04.08 running and send a release */
- if (sach_deact) {
+ /* Ask for SAPI != 0 to be freed first and stop if we need to wait */
+ if (_lchan_release_next_sapi(lchan) == 0)
+ return;
+
+ if (lchan->sach_deact) {
gsm48_send_rr_release(lchan);
+ return;
}
- DEBUGP(DRLL, "%s Recycling Channel\n", gsm_lchan_name(lchan));
+ rsl_release_request(lchan, 0, lchan->release_reason);
+ rsl_lchan_set_state(lchan, LCHAN_S_REL_REQ);
+}
+
+/* called from abis rsl */
+int rsl_lchan_rll_release(struct gsm_lchan *lchan, u_int8_t link_id)
+{
+ if (lchan->state != LCHAN_S_REL_REQ)
+ return -1;
+
+ if ((link_id & 0x7) != 0)
+ _lchan_handle_release(lchan);
+ return 0;
+}
+
+/* Consider releasing the channel now */
+int lchan_release(struct gsm_lchan *lchan, int sach_deact, int reason)
+{
+ DEBUGP(DRLL, "%s starting release sequence\n", gsm_lchan_name(lchan));
rsl_lchan_set_state(lchan, LCHAN_S_REL_REQ);
- rsl_release_request(lchan, 0, 0);
+
+ lchan->release_reason = reason;
+ lchan->sach_deact = sach_deact;
+ _lchan_handle_release(lchan);
return 1;
}