Move llc->MM/SM Gb specific glue code to its own file

Now that we have RANAP/Iu handling specificities in its own file, let's
have also Gb specific glue code for messages coming from llc up to MM/SM
layer in its own file. This way same entry points in gprs_gmm.c are used
by Gb and Iu: gsm0408_rcv_gmm() (for MM) and gsm0408_rcv_gsm() (for SM).

Change-Id: Iaf57922a0970c1d03f6f1d6337d27ae3d4aaf32c

3 files changed, 95 insertions, 62 deletions

diff --git a/src/gprs/Makefile.am b/src/gprs/Makefile.am
index 384b893f3..85ba9065b 100644
--- a/src/gprs/Makefile.am
+++ b/src/gprs/Makefile.am
@@ -60,6 +60,7 @@ osmo_gbproxy_LDADD = \
 	$(NULL)
 
 osmo_sgsn_SOURCES = \
+	gprs_gb.c \
 	gprs_gmm_attach.c \
 	gprs_gmm.c \
 	gprs_ranap.c \
diff --git a/src/gprs/gprs_gb.c b/src/gprs/gprs_gb.c
new file mode 100644
index 000000000..29bfc53ee
--- /dev/null
+++ b/src/gprs/gprs_gb.c
@@ -0,0 +1,91 @@
+/* Messages on the Gb interface (A/Gb mode) */
+
+/* (C) 2009-2015 by Harald Welte <laforge@gnumonks.org>
+ * (C) 2010 by On-Waves
+ * (C) 2019 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 <osmocom/core/rate_ctr.h>
+
+#include <osmocom/gprs/gprs_msgb.h>
+#include <osmocom/gprs/gprs_bssgp.h>
+
+#include "bscconfig.h"
+
+#include <osmocom/sgsn/gprs_sgsn.h>
+#include <osmocom/sgsn/gprs_gmm.h>
+#include <osmocom/sgsn/debug.h>
+
+/* Update the MM context state */
+static void gsm0408_gprs_notify_pdu_gb(struct sgsn_mm_ctx *mmctx)
+{
+	switch (mmctx->pmm_state) {
+	case MM_STANDBY:
+		mmctx_set_mm_state(mmctx, MM_READY);
+		break;
+	case MM_READY: /* RE-arm the timer upon receival of Gb PDUs */
+		mmctx_state_timer_start(mmctx, 3314);
+		break;
+	default:
+		break;
+	}
+}
+
+/* Main entry point for incoming 04.08 GPRS messages from Gb */
+int gsm0408_gprs_rcvmsg_gb(struct msgb *msg, struct gprs_llc_llme *llme,
+			   bool drop_cipherable)
+{
+	struct gsm48_hdr *gh = (struct gsm48_hdr *) msgb_gmmh(msg);
+	uint8_t pdisc = gsm48_hdr_pdisc(gh);
+	struct sgsn_mm_ctx *mmctx;
+	struct gprs_ra_id ra_id;
+	int rc = -EINVAL;
+
+	bssgp_parse_cell_id(&ra_id, msgb_bcid(msg));
+	mmctx = sgsn_mm_ctx_by_tlli(msgb_tlli(msg), &ra_id);
+	if (mmctx) {
+		msgid2mmctx(mmctx, msg);
+		rate_ctr_inc(&mmctx->ctrg->ctr[GMM_CTR_PKTS_SIG_IN]);
+		mmctx->gb.llme = llme;
+	}
+
+	/* MMCTX can be NULL */
+
+	if (mmctx)
+		gsm0408_gprs_notify_pdu_gb(mmctx);
+
+	switch (pdisc) {
+	case GSM48_PDISC_MM_GPRS:
+		rc = gsm0408_rcv_gmm(mmctx, msg, llme, drop_cipherable);
+		break;
+	case GSM48_PDISC_SM_GPRS:
+		rc = gsm0408_rcv_gsm(mmctx, msg, llme);
+		break;
+	default:
+		LOGMMCTXP(LOGL_NOTICE, mmctx,
+			"Unknown GSM 04.08 discriminator 0x%02x: %s\n",
+			pdisc, osmo_hexdump((uint8_t *)gh, msgb_l3len(msg)));
+		/* FIXME: return status message */
+		break;
+	}
+
+	/* MMCTX can be invalid */
+
+	return rc;
+}
diff --git a/src/gprs/gprs_gmm.c b/src/gprs/gprs_gmm.c
index 5700ee503..33ade4d83 100644
--- a/src/gprs/gprs_gmm.c
+++ b/src/gprs/gprs_gmm.c
@@ -124,7 +124,6 @@ static void mmctx_change_gtpu_endpoints_to_sgsn(struct sgsn_mm_ctx *mm_ctx)
 	}
 }
 
-static void mmctx_set_mm_state(struct sgsn_mm_ctx *ctx, enum gprs_pmm_state state);
 static void mmctx_state_timer_cb(void *_mm)
 {
 	struct sgsn_mm_ctx *mm = _mm;
@@ -149,7 +148,7 @@ static void mmctx_state_timer_cb(void *_mm)
 	}
 }
 
-static void mmctx_state_timer_start(struct sgsn_mm_ctx *mm, unsigned int T)
+void mmctx_state_timer_start(struct sgsn_mm_ctx *mm, unsigned int T)
 {
 	unsigned long seconds;
 
@@ -200,7 +199,7 @@ void mmctx_set_pmm_state(struct sgsn_mm_ctx *ctx, enum gprs_pmm_state state)
 	ctx->pmm_state = state;
 }
 
-static void mmctx_set_mm_state(struct sgsn_mm_ctx *ctx, enum gprs_pmm_state state)
+void mmctx_set_mm_state(struct sgsn_mm_ctx *ctx, enum gprs_pmm_state state)
 {
 	OSMO_ASSERT(ctx->ran_type == MM_CTX_T_GERAN_Gb);
 
@@ -304,7 +303,7 @@ static void gmm_copy_id(struct msgb *msg, const struct msgb *old)
 }
 
 /* Store BVCI/NSEI in MM context */
-static void msgid2mmctx(struct sgsn_mm_ctx *mm, const struct msgb *msg)
+void msgid2mmctx(struct sgsn_mm_ctx *mm, const struct msgb *msg)
 {
 	/* check for Iu or Gb */
 	if (!MSG_IU_UE_CTX(msg)) {
@@ -2926,64 +2925,6 @@ int gsm0408_gprs_force_reattach(struct sgsn_mm_ctx *mmctx)
 	return rc;
 }
 
-/* Update the MM context state */
-static void gsm0408_gprs_notify_pdu_gb(struct sgsn_mm_ctx *mmctx)
-{
-	switch (mmctx->pmm_state) {
-	case MM_STANDBY:
-		mmctx_set_mm_state(mmctx, MM_READY);
-		break;
-	case MM_READY: /* RE-arm the timer upon receival of Gb PDUs */
-		mmctx_state_timer_start(mmctx, 3314);
-		break;
-	default:
-		break;
-	}
-}
-
-/* Main entry point for incoming 04.08 GPRS messages from Gb */
-int gsm0408_gprs_rcvmsg_gb(struct msgb *msg, struct gprs_llc_llme *llme,
-			   bool drop_cipherable)
-{
-	struct gsm48_hdr *gh = (struct gsm48_hdr *) msgb_gmmh(msg);
-	uint8_t pdisc = gsm48_hdr_pdisc(gh);
-	struct sgsn_mm_ctx *mmctx;
-	struct gprs_ra_id ra_id;
-	int rc = -EINVAL;
-
-	bssgp_parse_cell_id(&ra_id, msgb_bcid(msg));
-	mmctx = sgsn_mm_ctx_by_tlli(msgb_tlli(msg), &ra_id);
-	if (mmctx) {
-		msgid2mmctx(mmctx, msg);
-		rate_ctr_inc(&mmctx->ctrg->ctr[GMM_CTR_PKTS_SIG_IN]);
-		mmctx->gb.llme = llme;
-	}
-
-	/* MMCTX can be NULL */
-
-	if (mmctx)
-		gsm0408_gprs_notify_pdu_gb(mmctx);
-
-	switch (pdisc) {
-	case GSM48_PDISC_MM_GPRS:
-		rc = gsm0408_rcv_gmm(mmctx, msg, llme, drop_cipherable);
-		break;
-	case GSM48_PDISC_SM_GPRS:
-		rc = gsm0408_rcv_gsm(mmctx, msg, llme);
-		break;
-	default:
-		LOGMMCTXP(LOGL_NOTICE, mmctx,
-			"Unknown GSM 04.08 discriminator 0x%02x: %s\n",
-			pdisc, osmo_hexdump((uint8_t *)gh, msgb_l3len(msg)));
-		/* FIXME: return status message */
-		break;
-	}
-
-	/* MMCTX can be invalid */
-
-	return rc;
-}
-
 int gprs_gmm_rx_suspend(struct gprs_ra_id *raid, uint32_t tlli)
 {
 	struct sgsn_mm_ctx *mmctx;