gprs_bssgp_pcu: explicit allocate & initialize bssgp_nsi instance

The instance bssgp_nsi is a global instance to be used by all
NS related functions. Previous the PCU allocated and initialized
the bssgp_nsi instance when (re-)connecting and freeing on disconnect.
The problem of the implicit initialisation is gprs_ns_vty_init(bssgp_nsi).
All vty init functions must be called before the configuration is read,
otherwise a previous vty written configuration is invalid.
Furthermore the vty modifications to the `ns` object were lost when the PCU has to
reconnect to the SGSN.

Fixes: OS#4024
Change-Id: I2aa53ea54e9352577f6280ad7b9d1d9da9f57eaf

2 files changed, 12 insertions, 17 deletions

diff --git a/src/gprs_bssgp_pcu.cpp b/src/gprs_bssgp_pcu.cpp
index 50f10db9..22abc6bd 100644
--- a/src/gprs_bssgp_pcu.cpp
+++ b/src/gprs_bssgp_pcu.cpp
@@ -875,11 +875,6 @@ static int gprs_ns_reconnect(struct gprs_nsvc *nsvc)
 {
 	struct gprs_nsvc *nsvc2;
 
-	if (!bssgp_nsi) {
-		LOGP(DBSSGP, LOGL_ERROR, "NS instance does not exist\n");
-		return -EINVAL;
-	}
-
 	if (nsvc != the_pcu.nsvc) {
 		LOGP(DBSSGP, LOGL_ERROR, "NSVC is invalid\n");
 		return -EBADF;
@@ -913,12 +908,6 @@ struct gprs_bssgp_pcu *gprs_bssgp_create_and_connect(struct gprs_rlcmac_bts *bts
 
 	the_pcu.bts = bts;
 
-	bssgp_nsi = gprs_ns_instantiate(&gprs_bssgp_ns_cb, tall_pcu_ctx);
-	if (!bssgp_nsi) {
-		LOGP(DBSSGP, LOGL_ERROR, "Failed to create NS instance\n");
-		return NULL;
-	}
-	gprs_ns_vty_init(bssgp_nsi);
 	/* don't specify remote IP/port if SNS dialect is in use; Doing so would
 	 * issue a connect() on the socket, which prevents us to dynamically communicate
 	 * with any number of IP-SNS endpoints on the SGSN side */
@@ -930,8 +919,7 @@ struct gprs_bssgp_pcu *gprs_bssgp_create_and_connect(struct gprs_rlcmac_bts *bts
 	rc = gprs_ns_nsip_listen(bssgp_nsi);
 	if (rc < 0) {
 		LOGP(DBSSGP, LOGL_ERROR, "Failed to create socket\n");
-		gprs_ns_destroy(bssgp_nsi);
-		bssgp_nsi = NULL;
+		gprs_ns_close(bssgp_nsi);
 		return NULL;
 	}
 
@@ -945,8 +933,7 @@ struct gprs_bssgp_pcu *gprs_bssgp_create_and_connect(struct gprs_rlcmac_bts *bts
 		the_pcu.nsvc = gprs_ns_nsip_connect(bssgp_nsi, &dest, nsei, nsvci);
 	if (!the_pcu.nsvc) {
 		LOGP(DBSSGP, LOGL_ERROR, "Failed to create NSVCt\n");
-		gprs_ns_destroy(bssgp_nsi);
-		bssgp_nsi = NULL;
+		gprs_ns_close(bssgp_nsi);
 		return NULL;
 	}
 
@@ -954,8 +941,7 @@ struct gprs_bssgp_pcu *gprs_bssgp_create_and_connect(struct gprs_rlcmac_bts *bts
 	if (!the_pcu.bctx) {
 		LOGP(DBSSGP, LOGL_ERROR, "Failed to create BSSGP context\n");
 		the_pcu.nsvc = NULL;
-		gprs_ns_destroy(bssgp_nsi);
-		bssgp_nsi = NULL;
+		gprs_ns_close(bssgp_nsi);
 		return NULL;
 	}
 	the_pcu.bctx->ra_id.mcc = spoof_mcc ? : mcc;
diff --git a/src/pcu_main.cpp b/src/pcu_main.cpp
index 1003e3c4..fa075cdf 100644
--- a/src/pcu_main.cpp
+++ b/src/pcu_main.cpp
@@ -33,6 +33,8 @@
 #include <bts.h>
 #include <gprs_coding_scheme.h>
 #include <osmocom/pcu/pcuif_proto.h>
+#include "gprs_bssgp_pcu.h"
+
 extern "C" {
 #include "pcu_vty.h"
 #include <osmocom/gprs/gprs_bssgp.h>
@@ -291,6 +293,13 @@ int main(int argc, char *argv[])
 	else
 		fprintf(stderr, "Failed to initialize GSMTAP for %s\n", gsmtap_addr);
 
+	bssgp_nsi = gprs_ns_instantiate(&gprs_bssgp_ns_cb, tall_pcu_ctx);
+	if (!bssgp_nsi) {
+		LOGP(DBSSGP, LOGL_ERROR, "Failed to create NS instance\n");
+		exit(1);
+	}
+	gprs_ns_vty_init(bssgp_nsi);
+
 	rc = vty_read_config_file(config_file, NULL);
 	if (rc < 0 && config_given) {
 		fprintf(stderr, "Failed to parse the config file: '%s'\n",