dissolve libbsc: move all to src/osmo-bsc, link .o files

Move all of libbsc/ into osmo-bsc/, and separate/move some implementations to
allow linking from utils/* and ipaccess/* without pulling in unccessary
dependencies.

Some utilities use gsm_network and gsm_bts structs, which already include data
structures for fairly advanced uses. Move initialization that only osmo-bsc
needs into new bsc_network_init() and bsc_bts_alloc_register() functions, so
that the leaner tools can use the old gsm_* versions without the need to link
everything (e.g. handover and lchan alloc code).

In some instances, there need to be stubs if to cut off linking "just before
the RSL level" and prevent dependencies from creeping in.
- abis_rsl_rcvmsg(): the only program currently interpreting RSL messages is
  osmo-bsc, the utils are merely concerned with OML, if at all.
- paging_flush_bts(): ip.access nanobts models call this when the RSL link is
  dropped. Only osmo-bsc actually needs to do anything there.
- on_gsm_ts_init(): the mechanism to trigger timeslot initialization is related
  to OML, while this action to take on init would pull in RSL dependencies.
utils/ and ipaccess/ each have a stubs.c file to implement these stubs. Tests
implement stubs inline where required.

From src/utils/, src/ipaccess/ and tests/*/, link in .o files from osmo-bsc/.
In order for this to work, the osmo-bsc subdir must be built before the other
source trees. (An alternative would be to include the .c files as sources, but
that would re-compile them in every source tree. Not a large burden really, but
unless linking .o files gives problems, let's have the quicker build.)

Minor obvious cleanups creep in with this patch, I will not bother to name them
individually now unless code review asks me to.

Rationale:

1) libbsc has been separate to use it for osmo-nitb and osmo-bsc in the old
openbsc.git. This is no longer required, and spreading over libbsc and osmo-bsc
is distracting.

2) Recently, ridiculous linking requirements have made adding new functions
cumbersome, because libbsc has started depending on osmo-bsc/*.c
implementations: on gscon FSM and bssap functions. For example, neither
bs11_config nor ipaccess-config nor bts_test need handover_cfg or BSSMAP
message composition. It makes no sense to link the entire osmo-bsc to it, nor
do we want to keep adding stubs to each linking realm.

Change-Id: I36a586726f5818121abe54d25654819fc451d3bf

3 files changed, 46 insertions, 6 deletions

diff --git a/src/utils/Makefile.am b/src/utils/Makefile.am
index 6e21ccc78..543344b53 100644
--- a/src/utils/Makefile.am
+++ b/src/utils/Makefile.am
@@ -46,15 +46,18 @@ endif
 
 bs11_config_SOURCES = \
 	bs11_config.c \
+	stubs.c \
 	$(NULL)
 
 bs11_config_LDADD = \
-	$(top_builddir)/src/libbsc/libbsc.a \
+	$(top_builddir)/src/osmo-bsc/abis_nm.o \
+	$(top_builddir)/src/osmo-bsc/bts_siemens_bs11.o \
+	$(top_builddir)/src/osmo-bsc/e1_config.o \
+	$(top_builddir)/src/osmo-bsc/gsm_data.o \
+	$(top_builddir)/src/osmo-bsc/net_init.o \
 	$(LIBOSMOCORE_LIBS) \
 	$(LIBOSMOGSM_LIBS) \
 	$(LIBOSMOABIS_LIBS) \
-	$(LIBOSMOSIGTRAN_LIBS) \
-	$(LIBOSMOMGCPCLIENT_LIBS) \
 	$(NULL)
 
 isdnsync_SOURCES = \
@@ -114,12 +117,14 @@ osmo_meas_udp2db_CFLAGS = \
 
 meas_json_SOURCES = \
 	meas_json.c \
+	stubs.c \
 	$(NULL)
 
 meas_json_LDADD = \
-	$(top_builddir)/src/libbsc/libbsc.a \
+	$(top_builddir)/src/osmo-bsc/gsm_data.o \
 	$(LIBOSMOCORE_LIBS) \
 	$(LIBOSMOGSM_LIBS) \
+	$(LIBOSMOABIS_LIBS) \
 	$(NULL)
 
 meas_json_CFLAGS = \
diff --git a/src/utils/bs11_config.c b/src/utils/bs11_config.c
index 8d4de0152..ae307c796 100644
--- a/src/utils/bs11_config.c
+++ b/src/utils/bs11_config.c
@@ -32,7 +32,6 @@
 
 #include <sys/stat.h>
 
-#include <osmocom/bsc/common_bsc.h>
 #include <osmocom/bsc/abis_nm.h>
 #include <osmocom/core/msgb.h>
 #include <osmocom/core/utils.h>
@@ -915,7 +914,7 @@ int main(int argc, char **argv)
 	handle_options(argc, argv);
 	bts_model_bs11_init();
 
-	gsmnet = bsc_network_init(tall_bs11cfg_ctx);
+	gsmnet = gsm_network_init(tall_bs11cfg_ctx);
 	if (!gsmnet) {
 		fprintf(stderr, "Unable to allocate gsm network\n");
 		exit(1);
diff --git a/src/utils/stubs.c b/src/utils/stubs.c
new file mode 100644
index 000000000..624797fde
--- /dev/null
+++ b/src/utils/stubs.c
@@ -0,0 +1,36 @@
+/* Stubs required for linking */
+
+/* (C) 2018 by sysmocom s.f.m.c. GmbH <info@sysmocom.de>
+ *
+ * All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <stdbool.h>
+struct gsm_bts_trx_ts;
+struct msgb;
+
+bool on_gsm_ts_init(struct gsm_bts_trx_ts *ts)
+{
+	/* No TS init required here. */
+	return true;
+}
+
+int abis_rsl_rcvmsg(struct msgb *msg)
+{
+	/* No RSL handling here */
+	return 0;
+}