Change in osmo-bsc[master]: handover_logic: make sure IPACC is done before MGCP

[dexter]

dexter has uploaded this change for review. ( https://gerrit.osmocom.org/10039


Change subject: handover_logic: make sure IPACC is done before MGCP
......................................................................

handover_logic: make sure IPACC is done before MGCP

During handover, the IPACC negotiaton on RSL level must be done
at least to the point where the BSC knows the IP-Address and the
Port of the new BTS. Only when this data is known the handover
logic may emit the GSCON_EV_HO_COMPL to tell the GSCON FSM that
the handover is complete (including IPACC)

- Add a signal handler that listens to SS_ABISIP signals.
- In cases where IPACC has not been done yet, postpone GSCON_EV_HO_COMPL
  and let it send by the signal handler as soon as S_ABISIP_CRCX_ACK
  arrives.

Change-Id: I01f05f5d8abe07a0d063e84a1984ac5797afb4f7
Related: OS#3396
---
M include/osmocom/bsc/gsm_data.h
M src/osmo-bsc/handover_logic.c
M tests/handover/handover_test.c
3 files changed, 47 insertions(+), 2 deletions(-)



  git pull ssh://gerrit.osmocom.org:29418/osmo-bsc refs/changes/39/10039/1

diff --git a/include/osmocom/bsc/gsm_data.h b/include/osmocom/bsc/gsm_data.h
index 5794617..1106176 100644
--- a/include/osmocom/bsc/gsm_data.h
+++ b/include/osmocom/bsc/gsm_data.h
@@ -428,6 +428,12 @@
 			uint8_t rr_cause;
 			bool valid;
 		} ass_compl;
+
+		/* info we need to postpone the GSCON_EV_HO_COMPL event
+		 * (see also handover_logic.c, function ho_gsm48_ho_compl() */
+		struct {
+			bool postponed;
+		} ho_compl;
 	} abis_ip;
 
 	uint8_t rqd_ta;
diff --git a/src/osmo-bsc/handover_logic.c b/src/osmo-bsc/handover_logic.c
index 960bf69..ebc80b2 100644
--- a/src/osmo-bsc/handover_logic.c
+++ b/src/osmo-bsc/handover_logic.c
@@ -329,8 +329,19 @@
 	handover_free(ho);
 	new_lchan->conn->ho = NULL;
 
-	/* Inform the GSCON FSM that the handover is complete */
-	osmo_fsm_inst_dispatch(new_lchan->conn->fi, GSCON_EV_HO_COMPL, NULL);
+	/* It may be that the RSL RTP port/IP negotiation is not done yet. In
+	 * this case we may not acknowledge the handover as completed yet. We
+	 * must postpone GSCON_EV_HO_COMPL and wait for S_ABISIP_CRCX_ACK in
+	 * order to be sure that the RTP port/IP information inside
+	 * lchan->abis_ip is populated with valid data.
+	 * (see also callback function: abisip_sig_cb()) */
+	if (new_lchan->abis_ip.bound_port != 0) {
+		/* Inform the GSCON FSM that the handover is complete */
+		osmo_fsm_inst_dispatch(new_lchan->conn->fi, GSCON_EV_HO_COMPL, NULL);
+		new_lchan->abis_ip.ho_compl.postponed = false;
+	} else
+		new_lchan->abis_ip.ho_compl.postponed = true;
+
 	return 0;
 }
 
@@ -392,6 +403,25 @@
 	return 0;
 }
 
+static int abisip_sig_cb(unsigned int subsys, unsigned int signal,
+			 void *handler_data, void *signal_data)
+{
+	struct gsm_lchan *lchan = signal_data;
+
+	if (subsys != SS_ABISIP)
+		return 0;
+
+	switch (signal) {
+	case S_ABISIP_CRCX_ACK:
+		if (lchan->abis_ip.ho_compl.postponed) {
+			lchan->abis_ip.ho_compl.postponed = false;
+			osmo_fsm_inst_dispatch(lchan->conn->fi, GSCON_EV_HO_COMPL, NULL);
+		}
+		break;
+	}
+	return 0;
+}
+
 static int ho_logic_sig_cb(unsigned int subsys, unsigned int signal,
 			   void *handler_data, void *signal_data)
 {
@@ -437,6 +467,11 @@
 static __attribute__((constructor)) void on_dso_load_ho_logic(void)
 {
 	osmo_signal_register_handler(SS_LCHAN, ho_logic_sig_cb, NULL);
+
+	/* Note: We must also listen to ABISIP events to make sure that all
+	 * RTP port/IP negotiation with the BTS is done before we acknowledge
+	 * the handover as completed. */
+	osmo_signal_register_handler(SS_ABISIP, abisip_sig_cb, NULL);
 }
 
 /* Count number of currently ongoing handovers
diff --git a/tests/handover/handover_test.c b/tests/handover/handover_test.c
index 769fd06..57e7c11 100644
--- a/tests/handover/handover_test.c
+++ b/tests/handover/handover_test.c
@@ -416,6 +416,10 @@
 	msg->l2h = (unsigned char *)rh;
 	msg->l3h = (unsigned char *)gh;
 
+	/* Pretend that the the IPACC negotiation has been done already */
+	lchan->abis_ip.bound_port = 1;
+	lchan->abis_ip.ho_compl.postponed = false;
+
 	abis_rsl_rcvmsg(msg);
 }
 

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Gerrit-Project: osmo-bsc
Gerrit-Branch: master
Gerrit-MessageType: newchange
Gerrit-Change-Id: I01f05f5d8abe07a0d063e84a1984ac5797afb4f7
Gerrit-Change-Number: 10039
Gerrit-PatchSet: 1
Gerrit-Owner: dexter <pmaier at sysmocom.de>
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