improve HNBAP error logging

We have a situation where HNBAP is not answered by osmo-hnbgw, and the
log is all silent. Add logging to a lot more of the possible HNBAP
failure paths to find out what is wrong.

Related: SYS#6810
Change-Id: I17d2809f59087d32e7c11a3ada1d3fadf6f0b660
---
M src/osmo-hnbgw/hnbgw.c
M src/osmo-hnbgw/hnbgw_hnbap.c
2 files changed, 33 insertions(+), 4 deletions(-)

diff --git a/src/osmo-hnbgw/hnbgw.c b/src/osmo-hnbgw/hnbgw.c
index 6f74d04..43fcaca 100644
--- a/src/osmo-hnbgw/hnbgw.c
+++ b/src/osmo-hnbgw/hnbgw.c
@@ -155,8 +155,7 @@
 	struct ue_context *ue;
 
 	ue = talloc_zero(g_hnbgw, struct ue_context);
-	if (!ue)
-		return NULL;
+	OSMO_ASSERT(ue);
 
 	ue->hnb = hnb;
 	if (imsi)
diff --git a/src/osmo-hnbgw/hnbgw_hnbap.c b/src/osmo-hnbgw/hnbgw_hnbap.c
index b220918..f860173 100644
--- a/src/osmo-hnbgw/hnbgw_hnbap.c
+++ b/src/osmo-hnbgw/hnbgw_hnbap.c
@@ -194,6 +194,9 @@
 	rc = hnbap_encode_ueregisteraccepties(&accept_out, &accept);
 	ASN_STRUCT_FREE_CONTENTS_ONLY(asn_DEF_OCTET_STRING, &accept.uE_Identity.choice.iMSI);
 	if (rc < 0) {
+		LOGHNB(ue->hnb, DHNBAP, LOGL_ERROR,
+		       "Failed to encode HNBAP UE Register Accept message for UE IMSI-%s TMSI-0x%08x\n",
+		       ue->imsi, ue->tmsi);
 		return rc;
 	}
 
@@ -204,7 +207,12 @@
 
 	ASN_STRUCT_FREE_CONTENTS_ONLY(asn_DEF_HNBAP_UERegisterAccept, &accept_out);
 
-	return hnbgw_hnbap_tx(ue->hnb, msg);
+	rc = hnbgw_hnbap_tx(ue->hnb, msg);
+	if (rc)
+		LOGHNB(ue->hnb, DHNBAP, LOGL_ERROR,
+		       "Failed to enqueue HNBAP UE Register Accept message for UE IMSI-%s TMSI-0x%08x\n",
+		       ue->imsi, ue->tmsi);
+	return rc;
 }
 
 static int hnbgw_tx_ue_register_rej(struct hnb_context *hnb, HNBAP_UE_Identity_t *ue_id, const struct HNBAP_Cause *cause)
@@ -426,6 +434,7 @@
 	}
 
 	if (rc < 0) {
+		LOGHNB(hnb, DHNBAP, LOGL_ERROR, "Failed to encode HNBAP UE Register Accept for TMSI 0x%08x\n", tmsi);
 		/* Encoding failed. Nothing in 'accept_out'. */
 		/* If we allocated the UE context but the UE REGISTER fails, get rid of it again: there will likely
 		 * never be a UE DE-REGISTER for this UE from the HNB, and the ue_context would linger forever. */
@@ -441,6 +450,8 @@
 						&accept_out);
 	rc = hnbgw_hnbap_tx(hnb, msg);
 	ASN_STRUCT_FREE_CONTENTS_ONLY(asn_DEF_HNBAP_UERegisterAccept, &accept_out);
+	if (rc)
+		LOGHNB(hnb, DHNBAP, LOGL_ERROR, "Failed to transmit HNBAP UE Register Accept for TMSI 0x%08x\n", tmsi);
 	return rc;
 }
 
@@ -642,14 +653,19 @@
 	ue = ue_context_by_imsi(imsi);
 	if (!ue)
 		ue = ue_allocated = ue_context_alloc(ctx, imsi, 0);
+	else
+		LOGHNB(ctx, DHNBAP, LOGL_DEBUG, "UE context for IMSI %s already exists\n", imsi);
 
 	/* Send UERegisterAccept */
 	rc = hnbgw_tx_ue_register_acc(ue);
 	if (rc < 0) {
+		LOGHNB(ctx, DHNBAP, LOGL_ERROR, "Failed to transmit HNBAP UE Register Accept for IMSI %s\n", imsi);
 		/* If we allocated the UE context but the UE REGISTER fails, get rid of it again: there will likely
 		 * never be a UE DE-REGISTER for this UE from the HNB, and the ue_context would linger forever. */
-		if (ue_allocated)
+		if (ue_allocated) {
 			ue_context_free(ue_allocated);
+			LOGHNB(ctx, DHNBAP, LOGL_INFO, "Freed UE context for IMSI %s\n", imsi);
+		}
 	}
 free_and_return_rc:
 	hnbap_free_ueregisterrequesties(&ies);

