mscsplit: various preparations to separate MSC from BSC

Disable large parts of the code that depend on BSC presence.

Don't set msg->lchan nor msg->dst.
Don't use lchan in libmsc.
Decouple lac from bts.

Prepare entry/exit point for MSC -> BSC and MSC -> RNC communication:
Add msc_ifaces.[hc], a_iface.c, with a general msc_tx_dtap() to redirect to
different interfaces depending on the actual subscriber connection.
While iu_tx() is going to be functional fairly soon, the a_tx() is going to be
just a dummy for some time (see comment).
Add Iu specific fields in gsm_subscriber_connection: the UE connection pointer
and an indicator for the Integrity Protection status on Iu (to be fully
implemented in later commits).
Add lac member to gsm_subscriber_connection, to allow decoupling from
bts->location_area_code. The conn->lac will actually be set in iu.c in an
upcoming commit ("add iucs.[hc]").

move to libcommon-cs: gsm48_extract_mi(), gsm48_paging_extract_mi().

libmsc: duplicate gsm0808 / gsm48 functions (towards BSC).
In osmo-nitb, libmsc would directly call the functions on the BSC level, not
always via the bsc_api. When separating libmsc from libbsc, some functions are
missing from the linkage.
Hence duplicate these functions to libmsc, add an msc_ prefix for clarity, also
add a _tx to gsm0808_cipher_mode():
* add msc_gsm0808_tx_cipher_mode() (dummy/stub)
* add msc_gsm48_tx_mm_serv_ack()
* add msc_gsm48_tx_mm_serv_rej()
Call these from libmsc instead of
* gsm0808_cipher_mode()
* gsm48_tx_mm_serv_ack()
* gsm48_tx_mm_serv_rej()
Also add a comment related to msc_gsm0808_tx_cipher_mode() in two places.

Temporarily disable all paging to be able to link libmsc without libbsc.
Skip the paging part of channel_test because the paging is now disabled.
In osmo-nitb, paging is done on BSC level and MSC level "at the same time".
When the new MSC is fully operational, paging will be controlled separately on
the MSC level, and the BSC (RNC) level will be instructed over an IuCS or
A-interface to negotiate paging with the MS (UE). This MSC level paging does
not yet exist and will be added in subsequent commits.

msc_compl_l3(): publish in .h, tweak return value.  Use new libmsc enum values
for return val, to avoid dependency on libbsc headers.  Make callable from
other scopes: publish in osmo_msc.h and remove 'static' in osmo_msc.c

add gsm_encr to subscr_conn
move subscr_request to gsm_subscriber.h
subscr_request_channel() -> subscr_request_conn()
move to libmsc: osmo_stats_vty_add_cmds()
gsm_04_08: remove apply_codec_restrictions()
gsm0408_test: use NULL for root ctx
move to libbsc: gsm_bts_neighbor()
move to libbsc: lchan_next_meas_rep()
move vty config for t3212 to network level (periodic lu)
remove unneccessary linking from some tests
remove handle_abisip_signal()
abis_rsl.c: don't use libvlr from libbsc

Change-Id: I9cf80f9c2c8a53a29e42f000029e680a9922cb41

4 files changed, 40 insertions, 34 deletions

diff --git a/openbsc/src/libbsc/abis_rsl.c b/openbsc/src/libbsc/abis_rsl.c
index 2a0b9a9a4..441b3861b 100644
--- a/openbsc/src/libbsc/abis_rsl.c
+++ b/openbsc/src/libbsc/abis_rsl.c
@@ -1382,8 +1382,6 @@ static void print_meas_rep(struct gsm_lchan *lchan, struct gsm_meas_rep *mr)
 	if (lchan && lchan->conn) {
 		if (lchan->conn->bsub)
 			name = bsc_subscr_name(lchan->conn->bsub);
-		else if (lchan->conn->subscr)
-			name = lchan->conn->subscr->imsi;
 		else
 			name = lchan->name;
 	}
@@ -1425,6 +1423,19 @@ static void print_meas_rep(struct gsm_lchan *lchan, struct gsm_meas_rep *mr)
 	}
 }
 
+static struct gsm_meas_rep *lchan_next_meas_rep(struct gsm_lchan *lchan)
+{
+	struct gsm_meas_rep *meas_rep;
+
+	meas_rep = &lchan->meas_rep[lchan->meas_rep_idx];
+	memset(meas_rep, 0, sizeof(*meas_rep));
+	meas_rep->lchan = lchan;
+	lchan->meas_rep_idx = (lchan->meas_rep_idx + 1)
+					% ARRAY_SIZE(lchan->meas_rep);
+
+	return meas_rep;
+}
+
 static int rsl_rx_meas_res(struct msgb *msg)
 {
 	struct abis_rsl_dchan_hdr *dh = msgb_l2(msg);
diff --git a/openbsc/src/libbsc/bsc_vty.c b/openbsc/src/libbsc/bsc_vty.c
index 91f01591d..dcb1e6ee7 100644
--- a/openbsc/src/libbsc/bsc_vty.c
+++ b/openbsc/src/libbsc/bsc_vty.c
@@ -597,18 +597,12 @@ static void config_write_bts_single(struct vty *vty, struct gsm_bts *bts)
 				(sp->penalty_time*20)+20, VTY_NEWLINE);
 	}
 
-	/* Is periodic LU enabled or disabled? */
-	if (bts->si_common.chan_desc.t3212 == 0)
-		vty_out(vty, "  no periodic location update%s", VTY_NEWLINE);
-	else
-		vty_out(vty, "  periodic location update %u%s",
-			bts->si_common.chan_desc.t3212 * 6, VTY_NEWLINE);
-
 	if (gsm_bts_get_radio_link_timeout(bts) < 0)
 		vty_out(vty, "  radio-link-timeout infinite%s", VTY_NEWLINE);
 	else
 		vty_out(vty, "  radio-link-timeout %d%s",
 			gsm_bts_get_radio_link_timeout(bts), VTY_NEWLINE);
+	
 	vty_out(vty, "  channel allocator %s%s",
 		bts->chan_alloc_reverse ? "descending" : "ascending",
 		VTY_NEWLINE);
@@ -850,6 +844,11 @@ static int config_write_net(struct vty *vty)
 			vty_out(vty, " timezone %d %d%s",
 				gsmnet->tz.hr, gsmnet->tz.mn, VTY_NEWLINE);
 	}
+	if (gsmnet->t3212 == 0)
+		vty_out(vty, " no periodic location update%s", VTY_NEWLINE);
+	else
+		vty_out(vty, " periodic location update %u%s",
+			gsmnet->t3212 * 6, VTY_NEWLINE);
 
 	return CMD_SUCCESS;
 }
@@ -4138,7 +4137,6 @@ int bsc_vty_init(struct gsm_network *network)
 	install_element_ve(&show_paging_group_cmd);
 
 	logging_vty_add_cmds(NULL);
-	osmo_stats_vty_add_cmds();
 
 	install_element(GSMNET_NODE, &cfg_net_neci_cmd);
 	install_element(GSMNET_NODE, &cfg_net_handover_cmd);
diff --git a/openbsc/src/libbsc/gsm_04_08_utils.c b/openbsc/src/libbsc/gsm_04_08_utils.c
index 3447d27cb..f9a613601 100644
--- a/openbsc/src/libbsc/gsm_04_08_utils.c
+++ b/openbsc/src/libbsc/gsm_04_08_utils.c
@@ -270,30 +270,6 @@ int send_siemens_mrpci(struct gsm_lchan *lchan,
 	return rsl_siemens_mrpci(lchan, &mrpci);
 }
 
-int gsm48_extract_mi(uint8_t *classmark2_lv, int length, char *mi_string, uint8_t *mi_type)
-{
-	/* Check the size for the classmark */
-	if (length < 1 + *classmark2_lv)
-		return -1;
-
-	uint8_t *mi_lv = classmark2_lv + *classmark2_lv + 1;
-	if (length < 2 + *classmark2_lv + mi_lv[0])
-		return -2;
-
-	*mi_type = mi_lv[1] & GSM_MI_TYPE_MASK;
-	return gsm48_mi_to_string(mi_string, GSM48_MI_SIZE, mi_lv+1, *mi_lv);
-}
-
-int gsm48_paging_extract_mi(struct gsm48_pag_resp *resp, int length,
-			    char *mi_string, uint8_t *mi_type)
-{
-	static const uint32_t classmark_offset =
-		offsetof(struct gsm48_pag_resp, classmark2);
-	uint8_t *classmark2_lv = (uint8_t *) &resp->classmark2;
-	return gsm48_extract_mi(classmark2_lv, length - classmark_offset,
-				mi_string, mi_type);
-}
-
 int gsm48_handle_paging_resp(struct gsm_subscriber_connection *conn,
 			     struct msgb *msg, struct bsc_subscr *bsub)
 {
diff --git a/openbsc/src/libbsc/handover_decision.c b/openbsc/src/libbsc/handover_decision.c
index 0f07bcac6..8d7e047b7 100644
--- a/openbsc/src/libbsc/handover_decision.c
+++ b/openbsc/src/libbsc/handover_decision.c
@@ -33,6 +33,27 @@
 #include <openbsc/handover.h>
 #include <osmocom/gsm/gsm_utils.h>
 
+/* Get reference to a neighbor cell on a given BCCH ARFCN */
+static struct gsm_bts *gsm_bts_neighbor(const struct gsm_bts *bts,
+					uint16_t arfcn, uint8_t bsic)
+{
+	struct gsm_bts *neigh;
+	/* FIXME: use some better heuristics here to determine which cell
+	 * using this ARFCN really is closest to the target cell.  For
+	 * now we simply assume that each ARFCN will only be used by one
+	 * cell */
+
+	llist_for_each_entry(neigh, &bts->network->bts_list, list) {
+		/* FIXME: this is probably returning the same bts again!? */
+		if (neigh->c0->arfcn == arfcn &&
+		    neigh->bsic == bsic)
+			return neigh;
+	}
+
+	return NULL;
+}
+
+
 /* issue handover to a cell identified by ARFCN and BSIC */
 static int handover_to_arfcn_bsic(struct gsm_lchan *lchan,
 				  uint16_t arfcn, uint8_t bsic)