Gb: add a second NS implementation

Reimplement NS with FSM.

Change-Id: I3525beef205588dfab9d3880a34115f1a2676e48
diff --git a/src/gb/gprs_ns2_vty.c b/src/gb/gprs_ns2_vty.c
new file mode 100644
index 0000000..81f88b6
--- /dev/null
+++ b/src/gb/gprs_ns2_vty.c
@@ -0,0 +1,833 @@
+/*! \file gprs_ns2_vty.c
+ * VTY interface for our GPRS Networks Service (NS) implementation. */
+
+/* (C) 2009-2014 by Harald Welte <laforge@gnumonks.org>
+ * (C) 2016-2017 by sysmocom - s.f.m.c. GmbH
+ * (C) 2020 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
+ * 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/>.
+ *
+ */
+
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <stdint.h>
+
+#include <arpa/inet.h>
+
+#include <osmocom/core/msgb.h>
+#include <osmocom/core/byteswap.h>
+#include <osmocom/core/talloc.h>
+#include <osmocom/core/select.h>
+#include <osmocom/core/rate_ctr.h>
+#include <osmocom/core/socket.h>
+#include <osmocom/core/sockaddr_str.h>
+#include <osmocom/core/linuxlist.h>
+#include <osmocom/core/socket.h>
+#include <osmocom/gprs/gprs_ns2.h>
+#include <osmocom/gsm/tlv.h>
+#include <osmocom/vty/vty.h>
+#include <osmocom/vty/command.h>
+#include <osmocom/vty/logging.h>
+#include <osmocom/vty/telnet_interface.h>
+#include <osmocom/vty/misc.h>
+
+#include "gprs_ns2_internal.h"
+
+struct ns2_vty_priv {
+	/* global listen */
+	struct osmo_sockaddr_str udp;
+	struct osmo_sockaddr_str frgreaddr;
+	int dscp;
+	enum gprs_ns2_vc_mode vc_mode;
+	/* force vc mode if another configuration forces
+	 * the vc mode. E.g. SNS configuration */
+	bool force_vc_mode;
+	char *force_vc_mode_reason;
+	bool frgre;
+
+	struct llist_head vtyvc;
+};
+
+struct ns2_vty_vc {
+	struct llist_head list;
+
+	struct osmo_sockaddr_str remote;
+	enum gprs_ns_ll ll;
+
+	/* old vty code doesnt support multiple NSVCI per NSEI */
+	uint16_t nsei;
+	uint16_t nsvci;
+	uint16_t frdlci;
+
+	bool remote_end_is_sgsn;
+	bool configured;
+};
+
+static struct gprs_ns2_inst *vty_nsi = NULL;
+static struct ns2_vty_priv priv;
+
+/* FIXME: this should go to some common file as it is copied
+ * in vty_interface.c of the BSC */
+static const struct value_string gprs_ns_timer_strs[] = {
+	{ 0, "tns-block" },
+	{ 1, "tns-block-retries" },
+	{ 2, "tns-reset" },
+	{ 3, "tns-reset-retries" },
+	{ 4, "tns-test" },
+	{ 5, "tns-alive" },
+	{ 6, "tns-alive-retries" },
+	{ 7, "tsns-prov" },
+	{ 0, NULL }
+};
+
+static void log_set_nsvc_filter(struct log_target *target,
+				struct gprs_ns2_vc *nsvc)
+{
+	if (nsvc) {
+		target->filter_map |= (1 << LOG_FLT_GB_NSVC);
+		target->filter_data[LOG_FLT_GB_NSVC] = nsvc;
+	} else if (target->filter_data[LOG_FLT_GB_NSVC]) {
+		target->filter_map = ~(1 << LOG_FLT_GB_NSVC);
+		target->filter_data[LOG_FLT_GB_NSVC] = NULL;
+	}
+}
+
+static struct cmd_node ns_node = {
+	L_NS_NODE,
+	"%s(config-ns)# ",
+	1,
+};
+
+static struct ns2_vty_vc *vtyvc_alloc(uint16_t nsei) {
+	struct ns2_vty_vc *vtyvc = talloc_zero(vty_nsi, struct ns2_vty_vc);
+	if (!vtyvc)
+		return vtyvc;
+
+	vtyvc->nsei = nsei;
+
+	llist_add(&vtyvc->list, &priv.vtyvc);
+
+	return vtyvc;
+}
+
+static void ns2_vc_free(struct ns2_vty_vc *vtyvc) {
+	if (!vtyvc)
+		return;
+
+	llist_del(&vtyvc->list);
+	talloc_free(vtyvc);
+}
+
+static struct ns2_vty_vc *vtyvc_by_nsei(uint16_t nsei, bool alloc_missing) {
+	struct ns2_vty_vc *vtyvc;
+	llist_for_each_entry(vtyvc, &priv.vtyvc, list) {
+		if (vtyvc->nsei == nsei)
+			return vtyvc;
+	}
+
+	if (alloc_missing) {
+		vtyvc = vtyvc_alloc(nsei);
+		if (!vtyvc)
+			return vtyvc;
+
+		vtyvc->nsei = nsei;
+	}
+
+	return NULL;
+}
+
+static int config_write_ns(struct vty *vty)
+{
+	struct ns2_vty_vc *vtyvc;
+	unsigned int i;
+	struct osmo_sockaddr_str sockstr;
+
+	vty_out(vty, "ns%s", VTY_NEWLINE);
+
+	/* global configuration must be written first, as some of it may be
+	 * relevant when creating the NSE/NSVC later below */
+
+	vty_out(vty, " encapsulation framerelay-gre enabled %u%s",
+		priv.frgre ? 1 : 0, VTY_NEWLINE);
+
+	if (priv.frgre) {
+		if (strlen(priv.frgreaddr.ip)) {
+			vty_out(vty, " encapsulation framerelay-gre local-ip %s%s",
+				sockstr.ip, VTY_NEWLINE);
+		}
+	} else {
+		if (strlen(priv.udp.ip)) {
+			vty_out(vty, " encapsulation udp local-ip %s%s",
+				priv.udp.ip, VTY_NEWLINE);
+		}
+
+		if (priv.udp.port)
+			vty_out(vty, " encapsulation udp local-port %u%s",
+				priv.udp.port, VTY_NEWLINE);
+	}
+
+	if (priv.dscp)
+		vty_out(vty, " encapsulation udp dscp %d%s",
+			priv.dscp, VTY_NEWLINE);
+
+	vty_out(vty, " encapsulation udp use-reset-block-unblock %s%s",
+		priv.vc_mode == NS2_VC_MODE_BLOCKRESET ? "enabled" : "disabled", VTY_NEWLINE);
+
+	llist_for_each_entry(vtyvc, &priv.vtyvc, list) {
+		vty_out(vty, " nse %u nsvci %u%s",
+			vtyvc->nsei, vtyvc->nsvci, VTY_NEWLINE);
+
+		vty_out(vty, " nse %u remote-role %s%s",
+			vtyvc->nsei, vtyvc->remote_end_is_sgsn ? "sgsn" : "bss",
+			VTY_NEWLINE);
+
+		switch (vtyvc->ll) {
+		case GPRS_NS_LL_UDP:
+			vty_out(vty, " nse %u encapsulation udp%s", vtyvc->nsei, VTY_NEWLINE);
+			vty_out(vty, " nse %u remote-ip %s%s",
+				vtyvc->nsei,
+				vtyvc->remote.ip,
+				VTY_NEWLINE);
+			vty_out(vty, " nse %u remote-port %u%s",
+				vtyvc->nsei, vtyvc->remote.port,
+				VTY_NEWLINE);
+			break;
+		case GPRS_NS_LL_FR_GRE:
+			vty_out(vty, " nse %u encapsulation framerelay-gre%s",
+				vtyvc->nsei, VTY_NEWLINE);
+			vty_out(vty, " nse %u remote-ip %s%s",
+				vtyvc->nsei,
+				vtyvc->remote.ip,
+				VTY_NEWLINE);
+			vty_out(vty, " nse %u fr-dlci %u%s",
+				vtyvc->nsei, vtyvc->frdlci,
+				VTY_NEWLINE);
+			break;
+		default:
+			break;
+		}
+	}
+
+	for (i = 0; i < ARRAY_SIZE(vty_nsi->timeout); i++)
+		vty_out(vty, " timer %s %u%s",
+			get_value_string(gprs_ns_timer_strs, i),
+			vty_nsi->timeout[i], VTY_NEWLINE);
+
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_ns, cfg_ns_cmd,
+      "ns",
+      "Configure the GPRS Network Service")
+{
+	vty->node = L_NS_NODE;
+	return CMD_SUCCESS;
+}
+
+static void dump_nsvc(struct vty *vty, struct gprs_ns2_vc *nsvc, bool stats)
+{
+	struct osmo_sockaddr_str remote;
+	struct osmo_sockaddr_str local;
+	struct osmo_sockaddr *sockaddr;
+
+	switch (nsvc->ll) {
+	case GPRS_NS_LL_UDP: {
+		sockaddr = gprs_ns2_ip_vc_sockaddr(nsvc);
+		if (!sockaddr) {
+			vty_out(vty, "unknown");
+			break;
+		}
+
+		if (osmo_sockaddr_str_from_sockaddr(
+					&remote,
+					&sockaddr->u.sas)) {
+			vty_out(vty, "unknown");
+			break;
+		}
+
+		vty_out(vty, "%s:%u <> %s:%u", local.ip, local.port, remote.ip, remote.port);
+		break;
+	}
+	case GPRS_NS_LL_FR_GRE:
+		/* TODO: implement dump_nse for FR GRE */
+	case GPRS_NS_LL_E1:
+		/* TODO: implement dump_nse for E1 */
+		break;
+	}
+
+	vty_out(vty, "Remote: %s ",
+		 gprs_ns2_ll_str(nsvc));
+
+	vty_out(vty, "%s%s", nsvc->ll == GPRS_NS_LL_UDP ? "UDP" : "FR-GRE", VTY_NEWLINE);
+
+	if (stats) {
+		vty_out_rate_ctr_group(vty, " ", nsvc->ctrg);
+		vty_out_stat_item_group(vty, " ", nsvc->statg);
+	}
+}
+
+static void dump_nse(struct vty *vty, const struct gprs_ns2_nse *nse, bool stats, bool persistent_only)
+{
+	struct gprs_ns2_vc *nsvc;
+
+	vty_out(vty, "NSEI %5u%s",
+		nse->nsei, VTY_NEWLINE);
+
+	gprs_ns2_sns_dump_vty(vty, nse, stats);
+	llist_for_each_entry(nsvc, &nse->nsvc, list) {
+		if (persistent_only) {
+			if (nsvc->persistent)
+				dump_nsvc(vty, nsvc, stats);
+		} else {
+			dump_nsvc(vty, nsvc, stats);
+		}
+	}
+}
+
+static void dump_ns(struct vty *vty, const struct gprs_ns2_inst *nsi, bool stats, bool persistent_only)
+{
+	struct gprs_ns2_nse *nse;
+
+	llist_for_each_entry(nse, &nsi->nse, list) {
+		dump_nse(vty, nse, stats, persistent_only);
+		break;
+	}
+
+}
+
+DEFUN(show_ns, show_ns_cmd, "show ns",
+	SHOW_STR "Display information about the NS protocol")
+{
+	dump_ns(vty, vty_nsi, false, false);
+	return CMD_SUCCESS;
+}
+
+DEFUN(show_ns_stats, show_ns_stats_cmd, "show ns stats",
+	SHOW_STR
+	"Display information about the NS protocol\n"
+	"Include statistics\n")
+{
+	dump_ns(vty, vty_nsi, true, false);
+	return CMD_SUCCESS;
+}
+
+DEFUN(show_ns_pers, show_ns_pers_cmd, "show ns persistent",
+	SHOW_STR
+	"Display information about the NS protocol\n"
+	"Show only persistent NS\n")
+{
+	dump_ns(vty, vty_nsi, true, true);
+	return CMD_SUCCESS;
+}
+
+DEFUN(show_nse, show_nse_cmd, "show ns (nsei|nsvc) <0-65535> [stats]",
+	SHOW_STR "Display information about the NS protocol\n"
+	"Select one NSE by its NSE Identifier\n"
+	"Select one NSE by its NS-VC Identifier\n"
+	"The Identifier of selected type\n"
+	"Include Statistics\n")
+{
+	struct gprs_ns2_inst *nsi = vty_nsi;
+	struct gprs_ns2_nse *nse;
+	struct gprs_ns2_vc *nsvc;
+	uint16_t id = atoi(argv[1]);
+	bool show_stats = false;
+
+	if (argc >= 3)
+		show_stats = true;
+
+	if (!strcmp(argv[0], "nsei")) {
+		nse = gprs_ns2_nse_by_nsei(nsi, id);
+		if (!nse) {
+			return CMD_WARNING;
+		}
+
+		dump_nse(vty, nse, show_stats, false);
+	} else {
+		nsvc = gprs_ns2_nsvc_by_nsvci(nsi, id);
+
+		if (!nsvc) {
+			vty_out(vty, "No such NS Entity%s", VTY_NEWLINE);
+			return CMD_WARNING;
+		}
+
+		dump_nsvc(vty, nsvc, show_stats);
+	}
+
+	return CMD_SUCCESS;
+}
+
+#define NSE_CMD_STR "Persistent NS Entity\n" "NS Entity ID (NSEI)\n"
+
+DEFUN(cfg_nse_nsvc, cfg_nse_nsvci_cmd,
+	"nse <0-65535> nsvci <0-65535>",
+	NSE_CMD_STR
+	"NS Virtual Connection\n"
+	"NS Virtual Connection ID (NSVCI)\n"
+	)
+{
+	struct ns2_vty_vc *vtyvc;
+
+	uint16_t nsei = atoi(argv[0]);
+	uint16_t nsvci = atoi(argv[1]);
+
+	vtyvc = vtyvc_by_nsei(nsei, true);
+	if (!vtyvc) {
+		vty_out(vty, "Can not allocate space %s", VTY_NEWLINE);
+		return CMD_WARNING;
+	}
+
+	vtyvc->nsvci = nsvci;
+
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_nse_remoteip, cfg_nse_remoteip_cmd,
+	"nse <0-65535> remote-ip " VTY_IPV46_CMD,
+	NSE_CMD_STR
+	"Remote IP Address\n"
+	"Remote IP Address\n")
+{
+	uint16_t nsei = atoi(argv[0]);
+	struct ns2_vty_vc *vtyvc;
+
+	vtyvc = vtyvc_by_nsei(nsei, true);
+	if (!vtyvc) {
+		vty_out(vty, "Can not allocate space %s", VTY_NEWLINE);
+		return CMD_WARNING;
+	}
+
+	osmo_sockaddr_str_from_str2(&vtyvc->remote, argv[1]);
+
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_nse_remoteport, cfg_nse_remoteport_cmd,
+	"nse <0-65535> remote-port <0-65535>",
+	NSE_CMD_STR
+	"Remote UDP Port\n"
+	"Remote UDP Port Number\n")
+{
+	uint16_t nsei = atoi(argv[0]);
+	uint16_t port = atoi(argv[1]);
+	struct ns2_vty_vc *vtyvc;
+
+	vtyvc = vtyvc_by_nsei(nsei, true);
+	if (!vtyvc) {
+		vty_out(vty, "Can not allocate space %s", VTY_NEWLINE);
+		return CMD_WARNING;
+	}
+
+	vtyvc->remote.port = port;
+
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_nse_fr_dlci, cfg_nse_fr_dlci_cmd,
+	"nse <0-65535> fr-dlci <16-1007>",
+	NSE_CMD_STR
+	"Frame Relay DLCI\n"
+	"Frame Relay DLCI Number\n")
+{
+	uint16_t nsei = atoi(argv[0]);
+	uint16_t dlci = atoi(argv[1]);
+	struct ns2_vty_vc *vtyvc;
+
+	vtyvc = vtyvc_by_nsei(nsei, true);
+	if (!vtyvc) {
+		vty_out(vty, "Can not allocate space %s", VTY_NEWLINE);
+		return CMD_WARNING;
+	}
+
+	if (vtyvc->ll != GPRS_NS_LL_FR_GRE) {
+		vty_out(vty, "Warning: seting FR DLCI on non-FR NSE%s",
+			VTY_NEWLINE);
+	}
+
+	vtyvc->frdlci = dlci;
+
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_nse_encaps, cfg_nse_encaps_cmd,
+	"nse <0-65535> encapsulation (udp|framerelay-gre)",
+	NSE_CMD_STR
+	"Encapsulation for NS\n"
+	"UDP/IP Encapsulation\n" "Frame-Relay/GRE/IP Encapsulation\n")
+{
+	uint16_t nsei = atoi(argv[0]);
+	struct ns2_vty_vc *vtyvc;
+
+	vtyvc = vtyvc_by_nsei(nsei, true);
+	if (!vtyvc) {
+		vty_out(vty, "Can not allocate space %s", VTY_NEWLINE);
+		return CMD_WARNING;
+	}
+
+	if (!strcmp(argv[1], "udp"))
+		vtyvc->ll = GPRS_NS_LL_UDP;
+	else
+		vtyvc->ll = GPRS_NS_LL_FR_GRE;
+
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_nse_remoterole, cfg_nse_remoterole_cmd,
+	"nse <0-65535> remote-role (sgsn|bss)",
+	NSE_CMD_STR
+	"Remote NSE Role\n"
+	"Remote Peer is SGSN\n"
+	"Remote Peer is BSS\n")
+{
+	uint16_t nsei = atoi(argv[0]);
+	struct ns2_vty_vc *vtyvc;
+
+	vtyvc = vtyvc_by_nsei(nsei, true);
+	if (!vtyvc) {
+		vty_out(vty, "Can not allocate space %s", VTY_NEWLINE);
+		return CMD_WARNING;
+	}
+
+	if (!strcmp(argv[1], "sgsn"))
+		vtyvc->remote_end_is_sgsn = 1;
+	else
+		vtyvc->remote_end_is_sgsn = 0;
+
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_no_nse, cfg_no_nse_cmd,
+	"no nse <0-65535>",
+	"Delete Persistent NS Entity\n"
+	"Delete " NSE_CMD_STR)
+{
+	uint16_t nsei = atoi(argv[0]);
+	struct ns2_vty_vc *vtyvc;
+
+	vtyvc = vtyvc_by_nsei(nsei, false);
+	if (!vtyvc) {
+		vty_out(vty, "The NSE %d does not exists.%s", nsei, VTY_NEWLINE);
+		return CMD_WARNING;
+	}
+
+	ns2_vc_free(vtyvc);
+
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_ns_timer, cfg_ns_timer_cmd,
+	"timer " NS_TIMERS " <0-65535>",
+	"Network Service Timer\n"
+	NS_TIMERS_HELP "Timer Value\n")
+{
+	int idx = get_string_value(gprs_ns_timer_strs, argv[0]);
+	int val = atoi(argv[1]);
+
+	if (idx < 0 || idx >= ARRAY_SIZE(vty_nsi->timeout))
+		return CMD_WARNING;
+
+	vty_nsi->timeout[idx] = val;
+
+	return CMD_SUCCESS;
+}
+
+#define ENCAPS_STR "NS encapsulation options\n"
+
+DEFUN(cfg_nsip_local_ip, cfg_nsip_local_ip_cmd,
+      "encapsulation udp local-ip " VTY_IPV46_CMD,
+	ENCAPS_STR "NS over UDP Encapsulation\n"
+	"Set the IP address on which we listen for NS/UDP\n"
+	"IP Address\n")
+{
+	osmo_sockaddr_str_from_str2(&priv.udp, argv[0]);
+
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_nsip_local_port, cfg_nsip_local_port_cmd,
+      "encapsulation udp local-port <0-65535>",
+	ENCAPS_STR "NS over UDP Encapsulation\n"
+	"Set the UDP port on which we listen for NS/UDP\n"
+	"UDP port number\n")
+{
+	unsigned int port = atoi(argv[0]);
+
+	priv.udp.port = port;
+
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_nsip_dscp, cfg_nsip_dscp_cmd,
+      "encapsulation udp dscp <0-255>",
+	ENCAPS_STR "NS over UDP Encapsulation\n"
+	"Set DSCP/TOS on the UDP socket\n" "DSCP Value\n")
+{
+	int dscp = atoi(argv[0]);
+	struct gprs_ns2_vc_bind *bind;
+
+	priv.dscp = dscp;
+
+	llist_for_each_entry(bind, &vty_nsi->binding, list) {
+		if (gprs_ns2_is_ip_bind(bind))
+			gprs_ns2_ip_bind_set_dscp(bind, dscp);
+	}
+
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_nsip_res_block_unblock, cfg_nsip_res_block_unblock_cmd,
+	"encapsulation udp use-reset-block-unblock (enabled|disabled)",
+	ENCAPS_STR "NS over UDP Encapsulation\n"
+	"Use NS-{RESET,BLOCK,UNBLOCK} procedures in violation of 3GPP TS 48.016\n"
+	"Enable NS-{RESET,BLOCK,UNBLOCK}\n"
+	"Disable NS-{RESET,BLOCK,UNBLOCK}\n")
+{
+	enum gprs_ns2_vc_mode vc_mode;
+	struct gprs_ns2_vc_bind *bind;
+
+	if (!strcmp(argv[0], "enabled"))
+		vc_mode = NS2_VC_MODE_BLOCKRESET;
+	else
+		vc_mode = NS2_VC_MODE_ALIVE;
+
+	if (priv.force_vc_mode) {
+		if (priv.vc_mode != vc_mode)
+		{
+			vty_out(vty, "Ignoring use-reset-block because it's already set by %s.%s",
+				priv.force_vc_mode_reason, VTY_NEWLINE);
+			return CMD_WARNING;
+		}
+
+		return CMD_SUCCESS;
+	}
+
+	priv.vc_mode = vc_mode;
+
+	llist_for_each_entry(bind, &vty_nsi->binding, list) {
+		gprs_ns2_bind_set_mode(bind, priv.vc_mode);
+	}
+
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_frgre_local_ip, cfg_frgre_local_ip_cmd,
+      "encapsulation framerelay-gre local-ip " VTY_IPV46_CMD,
+	ENCAPS_STR "NS over Frame Relay over GRE Encapsulation\n"
+	"Set the IP address on which we listen for NS/FR/GRE\n"
+	"IP Address\n")
+{
+	osmo_sockaddr_str_from_str2(&priv.frgreaddr, argv[0]);
+
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_frgre_enable, cfg_frgre_enable_cmd,
+      "encapsulation framerelay-gre enabled (1|0)",
+	ENCAPS_STR "NS over Frame Relay over GRE Encapsulation\n"
+	"Enable or disable Frame Relay over GRE\n"
+	"Enable\n" "Disable\n")
+{
+	int enabled = atoi(argv[0]);
+
+	priv.frgre = enabled;
+
+	return CMD_SUCCESS;
+}
+
+/* TODO: allow vty to reset/block/unblock nsvc/nsei */
+
+/* TODO: add filter for NSEI as ns1 code does */
+/* TODO: add filter for single connection by description */
+DEFUN(logging_fltr_nsvc,
+      logging_fltr_nsvc_cmd,
+      "logging filter nsvc nsvci <0-65535>",
+	LOGGING_STR FILTER_STR
+	"Filter based on NS Virtual Connection\n"
+	"Identify NS-VC by NSVCI\n"
+	"Numeric identifier\n")
+{
+	struct log_target *tgt;
+	struct gprs_ns2_vc *nsvc;
+	uint16_t id = atoi(argv[1]);
+
+	log_tgt_mutex_lock();
+	tgt = osmo_log_vty2tgt(vty);
+	if (!tgt) {
+		log_tgt_mutex_unlock();
+		return CMD_WARNING;
+	}
+
+	nsvc = gprs_ns2_nsvc_by_nsvci(vty_nsi, id);
+	if (!nsvc) {
+		vty_out(vty, "No NS-VC by that identifier%s", VTY_NEWLINE);
+		log_tgt_mutex_unlock();
+		return CMD_WARNING;
+	}
+
+	log_set_nsvc_filter(tgt, nsvc);
+	log_tgt_mutex_unlock();
+	return CMD_SUCCESS;
+}
+
+int gprs_ns2_vty_init(struct gprs_ns2_inst *nsi)
+{
+	static bool vty_elements_installed = false;
+
+	vty_nsi = nsi;
+	memset(&priv, 0, sizeof(struct ns2_vty_priv));
+	INIT_LLIST_HEAD(&priv.vtyvc);
+	priv.vc_mode = NS2_VC_MODE_BLOCKRESET;
+
+	/* Regression test code may call this function repeatedly, so make sure
+	 * that VTY elements are not duplicated, which would assert. */
+	if (vty_elements_installed)
+		return 0;
+	vty_elements_installed = true;
+
+	install_element_ve(&show_ns_cmd);
+	install_element_ve(&show_ns_stats_cmd);
+	install_element_ve(&show_ns_pers_cmd);
+	install_element_ve(&show_nse_cmd);
+	install_element_ve(&logging_fltr_nsvc_cmd);
+
+	install_element(CFG_LOG_NODE, &logging_fltr_nsvc_cmd);
+
+	install_element(CONFIG_NODE, &cfg_ns_cmd);
+	install_node(&ns_node, config_write_ns);
+	install_element(L_NS_NODE, &cfg_nse_nsvci_cmd);
+	install_element(L_NS_NODE, &cfg_nse_remoteip_cmd);
+	install_element(L_NS_NODE, &cfg_nse_remoteport_cmd);
+	install_element(L_NS_NODE, &cfg_nse_fr_dlci_cmd);
+	install_element(L_NS_NODE, &cfg_nse_encaps_cmd);
+	install_element(L_NS_NODE, &cfg_nse_remoterole_cmd);
+	install_element(L_NS_NODE, &cfg_no_nse_cmd);
+	install_element(L_NS_NODE, &cfg_ns_timer_cmd);
+	install_element(L_NS_NODE, &cfg_nsip_local_ip_cmd);
+	install_element(L_NS_NODE, &cfg_nsip_local_port_cmd);
+	install_element(L_NS_NODE, &cfg_nsip_dscp_cmd);
+	install_element(L_NS_NODE, &cfg_nsip_res_block_unblock_cmd);
+	install_element(L_NS_NODE, &cfg_frgre_enable_cmd);
+	install_element(L_NS_NODE, &cfg_frgre_local_ip_cmd);
+
+	/* TODO: nsvc/nsei command to reset states or reset/block/unblock nsei/nsvcs */
+
+	return 0;
+}
+
+/*!
+ * \brief gprs_ns2_vty_create parse the vty tree into ns nodes
+ * It has to be in different steps to ensure the bind is created before creating VCs.
+ * \return 0 on success
+ */
+int gprs_ns2_vty_create() {
+	struct ns2_vty_vc *vtyvc;
+	struct gprs_ns2_vc_bind *bind;
+	struct gprs_ns2_nse *nse;
+	struct gprs_ns2_vc *nsvc;
+	struct osmo_sockaddr sockaddr;
+
+	if (!vty_nsi)
+		return -1;
+
+	/* create binds, only support a single bind. either FR or UDP */
+	if (priv.frgre) {
+		/* TODO not yet supported !*/
+		return -1;
+	} else {
+		/* UDP */
+		osmo_sockaddr_str_to_sockaddr(&priv.udp, &sockaddr.u.sas);
+		gprs_ns2_ip_bind(vty_nsi, &sockaddr, priv.dscp, &bind);
+		if (!bind) {
+			/* TODO: could not bind on the specific address */
+			return -1;
+		}
+		gprs_ns2_bind_set_mode(bind, priv.vc_mode);
+	}
+
+	/* create vcs */
+	llist_for_each_entry(vtyvc, &priv.vtyvc, list) {
+		if (strlen(vtyvc->remote.ip) == 0) {
+			/* Invalid IP for VC */
+			continue;
+		}
+
+		if (!vtyvc->remote.port) {
+			/* Invalid port for VC */
+			continue;
+		}
+
+		if (osmo_sockaddr_str_to_sockaddr(&vtyvc->remote, &sockaddr.u.sas)) {
+			/* Invalid sockaddr for VC */
+			continue;
+		}
+
+		nse = gprs_ns2_nse_by_nsei(vty_nsi, vtyvc->nsei);
+		if (!nse) {
+			nse = gprs_ns2_create_nse(vty_nsi, vtyvc->nsei);
+			if (!nse) {
+				/* Could not create NSE for VTY */
+				continue;
+			}
+		}
+		nse->persistent = true;
+
+		if (bind) {
+			nsvc = gprs_ns2_ip_connect(bind,
+						   &sockaddr,
+						   nse,
+						   vtyvc->nsvci);
+			if (!nsvc) {
+				/* Could not create NSVC, connect failed */
+				continue;
+			}
+			nsvc->persistent = true;
+		}
+	}
+
+
+	return 0;
+}
+
+/*!
+ * \brief ns2_vty_bind_apply will be called when a new bind is created to apply vty settings
+ * \param bind
+ * \return
+ */
+void ns2_vty_bind_apply(struct gprs_ns2_vc_bind *bind)
+{
+	gprs_ns2_bind_set_mode(bind, priv.vc_mode);
+}
+
+/*!
+ * \brief ns2_vty_force_vc_mode force a mode and prevents the vty from overwriting it.
+ * \param force if true mode and reason will be set. false to allow modification via vty.
+ * \param mode
+ * \param reason A description shown to the user when a vty command wants to change the mode.
+ */
+void gprs_ns2_vty_force_vc_mode(bool force, enum gprs_ns2_vc_mode mode, char *reason)
+{
+	priv.force_vc_mode = force;
+
+	if (force) {
+		priv.vc_mode = mode;
+		priv.force_vc_mode_reason = reason;
+	}
+}