bsc: on-demand setup of nanoBTS and HSL femto sockets

The daemons set up nanoBTS and HSL femto sockets by default, ie. the
three sockets to support these two drivers are open even if we have
no BTS of that kind.

This patch enables on-demand socket creation, ie. we only enable them
if we have one BTS at least that requires it.

I added two new attributes to the gsm_bts object, they are:

* the start() function includes the code that we need to run to start
the BTS. This new function contains the socket creation in the
particular case of nanoBTS and HSL femto.

* the started boolean, which is used to know if we have already
started the BTS, ie. we have already invoked start().

Note that, I have splitted the bts_model_*_init() function into two
functions, the _init() functions that register the BTS driver
and the _start() functions that start BTS driver on-demand.

While I was at it, I added several changes/cleanups to this patch:

* Group all bts_model_*_init() calls into one function bts_init(),
which is called in the initialization path of osmo-nitb and
osmo-bsc.

* Add openbsc/bss.h that contains the declaration of
bsc_bootstrap_network, bsc_shutdown_net and bts_init.

* Add missing e1inp_init() in osmo-bsc.

* Fix missing declaration of hsl_setup in openbsc/e1_input.h

1 files changed, 8 insertions, 5 deletions

diff --git a/openbsc/src/libbsc/bsc_init.c b/openbsc/src/libbsc/bsc_init.c
index ecb4e443a..19453f79e 100644
--- a/openbsc/src/libbsc/bsc_init.c
+++ b/openbsc/src/libbsc/bsc_init.c
@@ -315,6 +315,14 @@ static int bootstrap_bts(struct gsm_bts *bts)
 {
 	int i, n;
 
+	if (bts->model->start && !bts->model->started) {
+		int ret = bts->model->start(bts->network);
+		if (ret < 0)
+			return ret;
+
+		bts->model->started = true;
+	}
+
 	/* FIXME: What about secondary TRX of a BTS?  What about a BTS that has TRX
 	 * in different bands? Why is 'band' a parameter of the BTS and not of the TRX? */
 	switch (bts->band) {
@@ -456,10 +464,5 @@ int bsc_bootstrap_network(int (*mncc_recv)(struct gsm_network *, struct msgb *),
 			return rc;
 		}
 	}
-
-	/* initialize nanoBTS support omce */
-	rc = ipaccess_setup(bsc_gsmnet);
-	rc = hsl_setup(bsc_gsmnet);
-
 	return 0;
 }