ns2: add support for frame relay

Add support for frame relay over dahdi hdlc device.
It's supporting lmi by q933 and supports both
SGSN and BSS.

Change-Id: Id3b49f93d33c271f77cd9c9db03cde6b727a4d30

2 files changed, 156 insertions, 0 deletions

diff --git a/include/osmocom/gprs/frame_relay.h b/include/osmocom/gprs/frame_relay.h
new file mode 100644
index 00000000..b382ea86
--- /dev/null
+++ b/include/osmocom/gprs/frame_relay.h
@@ -0,0 +1,136 @@
+/*! \file frame_relay.h */
+
+/* (C) 2020 Harald Welte <laforge@gnumonks.org>
+ * (C) 2020 sysmocom - s.f.m.c. GmbH
+ * Author: Alexander Couzens <lynxis@fe80.eu>
+ *
+ * All Rights Reserved
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#pragma once
+
+#include <osmocom/core/linuxlist.h>
+#include <osmocom/core/timer.h>
+#include <osmocom/core/utils.h>
+
+#include <stdint.h>
+
+struct osmo_tdef;
+struct msgb;
+
+enum osmo_fr_role {
+	FR_ROLE_USER_EQUIPMENT,
+	FR_ROLE_NETWORK_EQUIPMENT,
+};
+
+extern const struct value_string osmo_fr_role_names[];
+
+static inline const char *osmo_fr_role_str(enum osmo_fr_role role) {
+	return get_value_string(osmo_fr_role_names, role);
+}
+
+struct osmo_fr_network {
+	struct llist_head links;
+
+	unsigned int n391; 		/* full status polling counter */
+	unsigned int n392;		/* error threshold */
+	unsigned int n393;		/* monitored events count */
+
+	struct osmo_tdef *T_defs;	/* T391, T392 */
+};
+
+struct osmo_fr_dlc;
+
+/* Frame Relay Link */
+struct osmo_fr_link {
+	/* list in osmo_fr_network.links */
+	struct llist_head list;
+	struct osmo_fr_network *net;
+	enum osmo_fr_role role;
+	/* human-readable name */
+	const char *name;
+
+	/* value of the last received send sequence number field in the
+	 * link integrity verification information element */
+	uint8_t last_rx_seq;
+
+	/* value of the send sequence number field of the last link
+	 * integrity verification information element sent */
+	uint8_t last_tx_seq;
+
+	struct osmo_timer_list t391;
+	struct osmo_timer_list t392;
+
+	unsigned int polling_count;
+	unsigned int err_count;
+	unsigned int succeed;
+	/* the type of the last status enquiry */
+	uint8_t expected_rep;
+	bool state;
+
+	/* list of data link connections at this link */
+	struct llist_head dlc_list;
+
+	int (*unknown_dlc_rx_cb)(void *cb_data, struct msgb *msg);
+	void *unknown_dlc_rx_cb_data;
+
+	int (*tx_cb)(void *data, struct msgb *msg);
+	void *tx_cb_data;
+};
+
+/* Frame Relay Data Link Connection */
+struct osmo_fr_dlc {
+	/* entry in fr_link.dlc_list */
+	struct llist_head list;
+	struct osmo_fr_link *link;
+
+	uint16_t dlci;
+
+	/* is this DLC marked active for traffic? */
+	bool active;
+	/* was this DLC newly added? */
+	bool add;
+	/* is this DLC about to be destroyed */
+	bool del;
+
+	/* the local state needs to be transfered to the
+	 * UE. The NET must wait until the UE confirms it implicited by a seq number check */
+	bool state_send;
+
+	int (*rx_cb)(void *cb_data, struct msgb *msg);
+	void *rx_cb_data;
+};
+
+/* allocate a frame relay network */
+struct osmo_fr_network *osmo_fr_network_alloc(void *ctx);
+
+/* allocate a frame relay link in a given network */
+struct osmo_fr_link *osmo_fr_link_alloc(struct osmo_fr_network *net, enum osmo_fr_role role, const char *name);
+
+/* free a frame link in a given network */
+void osmo_fr_link_free(struct osmo_fr_link *link);
+
+/* allocate a data link connectoin on a given framerelay link */
+struct osmo_fr_dlc *osmo_fr_dlc_alloc(struct osmo_fr_link *link, uint16_t dlci);
+void osmo_fr_dlc_free(struct osmo_fr_dlc *dlc);
+
+struct osmo_fr_dlc *osmo_fr_dlc_by_dlci(struct osmo_fr_link *link, uint16_t dlci);
+
+int osmo_fr_rx(struct msgb *msg);
+int osmo_fr_tx_dlc(struct msgb *msg);
diff --git a/include/osmocom/gprs/gprs_ns2.h b/include/osmocom/gprs/gprs_ns2.h
index 3b47b3c0..dd4f4d5a 100644
--- a/include/osmocom/gprs/gprs_ns2.h
+++ b/include/osmocom/gprs/gprs_ns2.h
@@ -8,9 +8,11 @@
 
 #include <osmocom/core/prim.h>
 #include <osmocom/gprs/protocol/gsm_08_16.h>
+#include <osmocom/gprs/frame_relay.h>
 
 struct osmo_sockaddr;
 struct osmo_sockaddr_str;
+struct osmo_fr_network;
 
 struct gprs_ns2_inst;
 struct gprs_ns2_nse;
@@ -146,6 +148,23 @@ struct gprs_ns2_vc_bind *gprs_ns2_ip_bind_by_sockaddr(struct gprs_ns2_inst *nsi,
 						      const struct osmo_sockaddr *sockaddr);
 void gprs_ns2_bind_set_mode(struct gprs_ns2_vc_bind *bind, enum gprs_ns2_vc_mode mode);
 
+/* FR VL driver */
+struct gprs_ns2_vc_bind *gprs_ns2_fr_bind_by_netif(
+		struct gprs_ns2_inst *nsi,
+		const char *netif);
+const char *gprs_ns2_fr_bind_netif(struct gprs_ns2_vc_bind *bind);
+int gprs_ns2_fr_bind(struct gprs_ns2_inst *nsi,
+		     const char *netif,
+		     struct osmo_fr_network *fr_network,
+		     enum osmo_fr_role fr_role,
+		     struct gprs_ns2_vc_bind **result);
+int gprs_ns2_is_fr_bind(struct gprs_ns2_vc_bind *bind);
+struct gprs_ns2_vc *gprs_ns2_fr_nsvc_by_dlci(struct gprs_ns2_vc_bind *bind, uint16_t dlci);
+struct gprs_ns2_vc *gprs_ns2_fr_connect(struct gprs_ns2_vc_bind *bind,
+					uint16_t nsei,
+					uint16_t nsvci,
+					uint16_t dlci);
+
 /* create a VC connection */
 struct gprs_ns2_vc *gprs_ns2_ip_connect(struct gprs_ns2_vc_bind *bind,
 					const struct osmo_sockaddr *remote,
@@ -188,6 +207,7 @@ int gprs_ns2_frgre_bind(struct gprs_ns2_inst *nsi,
 			int dscp,
 			struct gprs_ns2_vc_bind **result);
 int gprs_ns2_is_frgre_bind(struct gprs_ns2_vc_bind *bind);
+uint16_t gprs_ns2_fr_nsvc_dlci(struct gprs_ns2_vc *nsvc);
 
 struct gprs_ns2_vc *gprs_ns2_nsvc_by_sockaddr_nse(
 		struct gprs_ns2_nse *nse,