/*
 * (C) 2010 by Harald Welte <laforge@gnumonks.org>
 * (C) 2010 by On-Waves
 * 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 <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>
#include <time.h>

#include <osmocom/core/talloc.h>
#include <osmocom/core/rate_ctr.h>

#include <openbsc/gsm_04_08.h>
#include <osmocom/gprs/gprs_ns.h>

#include <openbsc/debug.h>
#include <openbsc/gb_proxy.h>
#include <openbsc/gprs_utils.h>
#include <openbsc/vty.h>

#include <osmocom/vty/command.h>
#include <osmocom/vty/vty.h>
#include <osmocom/vty/misc.h>

static struct gbproxy_config *g_cfg = NULL;

/*
 * vty code for mgcp below
 */
static struct cmd_node gbproxy_node = {
	GBPROXY_NODE,
	"%s(config-gbproxy)# ",
	1,
};

static const struct value_string patch_modes[] = {
	{GBPROX_PATCH_DEFAULT, "default"},
	{GBPROX_PATCH_BSSGP, "bssgp"},
	{GBPROX_PATCH_LLC_ATTACH_REQ, "llc-attach-req"},
	{GBPROX_PATCH_LLC_ATTACH, "llc-attach"},
	{GBPROX_PATCH_LLC_GMM, "llc-gmm"},
	{GBPROX_PATCH_LLC_GSM, "llc-gsm"},
	{GBPROX_PATCH_LLC, "llc"},
	{0, NULL}
};

static void gbprox_vty_print_peer(struct vty *vty, struct gbproxy_peer *peer)
{
	struct gprs_ra_id raid;
	gsm48_parse_ra(&raid, peer->ra);

	vty_out(vty, "NSEI %5u, PTP-BVCI %5u, "
		"RAI %u-%u-%u-%u",
		peer->nsei, peer->bvci,
		raid.mcc, raid.mnc, raid.lac, raid.rac);
	if (peer->blocked)
		vty_out(vty, " [BVC-BLOCKED]");

	vty_out(vty, "%s", VTY_NEWLINE);
}

static int config_write_gbproxy(struct vty *vty)
{
	vty_out(vty, "gbproxy%s", VTY_NEWLINE);

	vty_out(vty, " sgsn nsei %u%s", g_cfg->nsip_sgsn_nsei,
		VTY_NEWLINE);

	if (g_cfg->core_mcc > 0)
		vty_out(vty, " core-mobile-country-code %d%s",
			g_cfg->core_mcc, VTY_NEWLINE);
	if (g_cfg->core_mnc > 0)
		vty_out(vty, " core-mobile-network-code %d%s",
			g_cfg->core_mnc, VTY_NEWLINE);
	if (g_cfg->core_apn != NULL) {
	       if (g_cfg->core_apn_size > 0) {
		       char str[500] = {0};
		       vty_out(vty, " core-access-point-name %s",
			       gprs_apn_to_str(str, g_cfg->core_apn,
						 g_cfg->core_apn_size));
	       } else {
		       vty_out(vty, " core-access-point-name none");
	       }
	       if (g_cfg->match_re)
		       vty_out(vty, " match-imsi %s%s",
			       g_cfg->match_re, VTY_NEWLINE);
	       else
		       vty_out(vty, "%s", VTY_NEWLINE);
	}

	if (g_cfg->patch_ptmsi > 0)
		vty_out(vty, " patch-ptmsi%s",
			VTY_NEWLINE);

	if (g_cfg->tlli_max_age > 0)
		vty_out(vty, " tlli-list max-age %d%s",
			g_cfg->tlli_max_age, VTY_NEWLINE);
	if (g_cfg->tlli_max_len > 0)
		vty_out(vty, " tlli-list max-length %d%s",
			g_cfg->tlli_max_len, VTY_NEWLINE);

	if (g_cfg->patch_mode != GBPROX_PATCH_DEFAULT)
		vty_out(vty, " patch-mode %s%s",
			get_value_string(patch_modes, g_cfg->patch_mode),
			VTY_NEWLINE);

	return CMD_SUCCESS;
}

DEFUN(cfg_gbproxy,
      cfg_gbproxy_cmd,
      "gbproxy",
      "Configure the Gb proxy")
{
	vty->node = GBPROXY_NODE;
	return CMD_SUCCESS;
}

DEFUN(cfg_nsip_sgsn_nsei,
      cfg_nsip_sgsn_nsei_cmd,
      "sgsn nsei <0-65534>",
      "SGSN information\n"
      "NSEI to be used in the connection with the SGSN\n"
      "The NSEI\n")
{
	unsigned int port = atoi(argv[0]);

	g_cfg->nsip_sgsn_nsei = port;
	return CMD_SUCCESS;
}

#define GBPROXY_CORE_MNC_STR "Use this network code for the core network\n"

DEFUN(cfg_gbproxy_core_mnc,
      cfg_gbproxy_core_mnc_cmd,
      "core-mobile-network-code <1-999>",
      GBPROXY_CORE_MNC_STR "NCC value\n")
{
	g_cfg->core_mnc = atoi(argv[0]);
	return CMD_SUCCESS;
}

DEFUN(cfg_gbproxy_no_core_mnc,
      cfg_gbproxy_no_core_mnc_cmd,
      "no core-mobile-network-code",
      NO_STR GBPROXY_CORE_MNC_STR)
{
	g_cfg->core_mnc = 0;
	return CMD_SUCCESS;
}

#define GBPROXY_CORE_MCC_STR "Use this country code for the core network\n"

DEFUN(cfg_gbproxy_core_mcc,
      cfg_gbproxy_core_mcc_cmd,
      "core-mobile-country-code <1-999>",
      GBPROXY_CORE_MCC_STR "MCC value\n")
{
	g_cfg->core_mcc = atoi(argv[0]);
	return CMD_SUCCESS;
}

DEFUN(cfg_gbproxy_no_core_mcc,
      cfg_gbproxy_no_core_mcc_cmd,
      "no core-mobile-country-code",
      NO_STR GBPROXY_CORE_MCC_STR)
{
	g_cfg->core_mcc = 0;
	return CMD_SUCCESS;
}

#define GBPROXY_CORE_APN_STR "Use this access point name (APN) for the backbone\n"
#define GBPROXY_CORE_APN_ARG_STR "Replace APN by this string\n" "Remove APN\n"

static int set_core_apn(struct vty *vty, const char *apn, const char *filter)
{
	const char *err_msg = NULL;
	int apn_len;

	if (!apn) {
		talloc_free(g_cfg->core_apn);
		g_cfg->core_apn = NULL;
		g_cfg->core_apn_size = 0;
		gbproxy_clear_patch_filter(g_cfg);
		return CMD_SUCCESS;
	}

	apn_len = strlen(apn);

	if (apn_len >= 100) {
		vty_out(vty, "APN string too long (max 99 chars)%s",
			VTY_NEWLINE);
		return CMD_WARNING;
	}

	if (!filter) {
		gbproxy_clear_patch_filter(g_cfg);
	} else if (gbproxy_set_patch_filter(g_cfg, filter, &err_msg) != 0) {
		vty_out(vty, "Match expression invalid: %s%s",
			err_msg, VTY_NEWLINE);
		return CMD_WARNING;
	}

	talloc_free(g_cfg->match_re);
	if (filter)
		/* TODO: replace NULL */
		g_cfg->match_re = talloc_strdup(NULL, filter);
	else
		g_cfg->match_re = NULL;

	if (apn_len == 0) {
		talloc_free(g_cfg->core_apn);
		/* TODO: replace NULL */
		g_cfg->core_apn = talloc_zero_size(NULL, 2);
		g_cfg->core_apn_size = 0;
	} else {
		/* TODO: replace NULL */
		g_cfg->core_apn =
			talloc_realloc_size(NULL, g_cfg->core_apn, apn_len + 1);
		g_cfg->core_apn_size =
			gprs_str_to_apn(g_cfg->core_apn, apn_len + 1, apn);
	}

	return CMD_SUCCESS;
}

DEFUN(cfg_gbproxy_core_apn,
      cfg_gbproxy_core_apn_cmd,
      "core-access-point-name (APN|none)",
      GBPROXY_CORE_APN_STR GBPROXY_CORE_APN_ARG_STR)
{
	if (strcmp(argv[0], "none") == 0)
		return set_core_apn(vty, "", NULL);
	else
		return set_core_apn(vty, argv[0], NULL);
}

DEFUN(cfg_gbproxy_core_apn_match,
      cfg_gbproxy_core_apn_match_cmd,
      "core-access-point-name (APN|none) match-imsi .REGEXP",
      GBPROXY_CORE_APN_STR GBPROXY_CORE_APN_ARG_STR
      "Only modify if the IMSI matches\n"
      "Regular expression for the match\n")
{
	if (strcmp(argv[0], "none") == 0)
		return set_core_apn(vty, "", argv[1]);
	else
		return set_core_apn(vty, argv[0], argv[1]);
}

DEFUN(cfg_gbproxy_no_core_apn,
      cfg_gbproxy_no_core_apn_cmd,
      "no core-access-point-name",
      NO_STR GBPROXY_CORE_APN_STR)
{
	return set_core_apn(vty, NULL, NULL);
}

#define GBPROXY_PATCH_PTMSI_STR "Patch P-TMSI/TLLI\n"

DEFUN(cfg_gbproxy_patch_ptmsi,
      cfg_gbproxy_patch_ptmsi_cmd,
      "patch-ptmsi",
      GBPROXY_PATCH_PTMSI_STR)
{
	g_cfg->patch_ptmsi = 1;

	return CMD_SUCCESS;
}

DEFUN(cfg_gbproxy_no_patch_ptmsi,
      cfg_gbproxy_no_patch_ptmsi_cmd,
      "no patch-ptmsi",
      NO_STR GBPROXY_PATCH_PTMSI_STR)
{
	g_cfg->patch_ptmsi = 0;

	return CMD_SUCCESS;
}

#define GBPROXY_TLLI_LIST_STR "Set TLLI list parameters\n"
#define GBPROXY_MAX_AGE_STR "Limit maximum age\n"

DEFUN(cfg_gbproxy_tlli_list_max_age,
      cfg_gbproxy_tlli_list_max_age_cmd,
      "tlli-list max-age <1-999999>",
      GBPROXY_TLLI_LIST_STR GBPROXY_MAX_AGE_STR
      "Maximum age in seconds\n")
{
	g_cfg->tlli_max_age = atoi(argv[0]);

	return CMD_SUCCESS;
}

DEFUN(cfg_gbproxy_tlli_list_no_max_age,
      cfg_gbproxy_tlli_list_no_max_age_cmd,
      "no tlli-list max-age",
      NO_STR GBPROXY_TLLI_LIST_STR GBPROXY_MAX_AGE_STR)
{
	g_cfg->tlli_max_age = 0;

	return CMD_SUCCESS;
}

#define GBPROXY_MAX_LEN_STR "Limit list length\n"

DEFUN(cfg_gbproxy_tlli_list_max_len,
      cfg_gbproxy_tlli_list_max_len_cmd,
      "tlli-list max-length <1-99999>",
      GBPROXY_TLLI_LIST_STR GBPROXY_MAX_LEN_STR
      "Maximum number of TLLIs in the list\n")
{
	g_cfg->tlli_max_len = atoi(argv[0]);

	return CMD_SUCCESS;
}

DEFUN(cfg_gbproxy_tlli_list_no_max_len,
      cfg_gbproxy_tlli_list_no_max_len_cmd,
      "no tlli-list max-length",
      NO_STR GBPROXY_TLLI_LIST_STR GBPROXY_MAX_LEN_STR)
{
	g_cfg->tlli_max_len = 0;

	return CMD_SUCCESS;
}


DEFUN(cfg_gbproxy_patch_mode,
      cfg_gbproxy_patch_mode_cmd,
      "patch-mode (default|bssgp|llc-attach-req|llc-attach|llc-gmm|llc-gsm|llc)",
      "Set patch mode\n"
      "Use build-in default (best effort, try to patch everything)\n"
      "Only patch BSSGP headers\n"
      "Patch BSSGP headers and LLC Attach Request messages\n"
      "Patch BSSGP headers and LLC Attach Request/Accept messages\n"
      "Patch BSSGP headers and LLC GMM messages\n"
      "Patch BSSGP headers, LLC GMM, and LLC GSM messages\n"
      "Patch BSSGP headers and all supported LLC messages\n"
      )
{
	int val = get_string_value(patch_modes, argv[0]);
	OSMO_ASSERT(val >= 0);
	g_cfg->patch_mode = val;
	return CMD_SUCCESS;
}

DEFUN(show_gbproxy, show_gbproxy_cmd, "show gbproxy [stats]",
       SHOW_STR "Display information about the Gb proxy\n" "Show statistics\n")
{
	struct gbproxy_peer *peer;
	int show_stats = argc >= 1;

	if (show_stats)
		vty_out_rate_ctr_group(vty, "", g_cfg->ctrg);

	llist_for_each_entry(peer, &g_cfg->bts_peers, list) {
		gbprox_vty_print_peer(vty, peer);

		if (show_stats)
			vty_out_rate_ctr_group(vty, "  ", peer->ctrg);
	}
	return CMD_SUCCESS;
}

DEFUN(show_gbproxy_tllis, show_gbproxy_tllis_cmd, "show gbproxy tllis",
       SHOW_STR "Display information about the Gb proxy\n" "Show TLLIs\n")
{
	struct gbproxy_peer *peer;
	char mi_buf[200];
	time_t now = time(NULL);

	llist_for_each_entry(peer, &g_cfg->bts_peers, list) {
		struct gbproxy_tlli_info *tlli_info;
		struct gbproxy_patch_state *state = &peer->patch_state;

		gbprox_vty_print_peer(vty, peer);

		llist_for_each_entry(tlli_info, &state->enabled_tllis, list) {
			time_t age = now - tlli_info->timestamp;
			if (tlli_info->mi_data_len > 0) {
				snprintf(mi_buf, sizeof(mi_buf), "(invalid)");
				gsm48_mi_to_string(mi_buf, sizeof(mi_buf),
						   tlli_info->mi_data,
						   tlli_info->mi_data_len);
			} else {
				snprintf(mi_buf, sizeof(mi_buf), "(none)");
			}
			vty_out(vty, "  TLLI %08x, IMSI %s, AGE %d%s",
				tlli_info->tlli.current, mi_buf, (int)age,
				VTY_NEWLINE);
		}
	}
	return CMD_SUCCESS;
}

DEFUN(delete_gb_bvci, delete_gb_bvci_cmd,
	"delete-gbproxy-peer <0-65534> bvci <2-65534>",
	"Delete a GBProxy peer by NSEI and optionally BVCI\n"
	"NSEI number\n"
	"Only delete peer with a matching BVCI\n"
	"BVCI number\n")
{
	const uint16_t nsei = atoi(argv[0]);
	const uint16_t bvci = atoi(argv[1]);
	int counter;

	counter = gbproxy_cleanup_peers(g_cfg, nsei, bvci);

	if (counter == 0) {
		vty_out(vty, "BVC not found%s", VTY_NEWLINE);
		return CMD_WARNING;
	}

	return CMD_SUCCESS;
}

DEFUN(delete_gb_nsei, delete_gb_nsei_cmd,
	"delete-gbproxy-peer <0-65534> (only-bvc|only-nsvc|all) [dry-run]",
	"Delete a GBProxy peer by NSEI and optionally BVCI\n"
	"NSEI number\n"
	"Only delete BSSGP connections (BVC)\n"
	"Only delete dynamic NS connections (NS-VC)\n"
	"Delete BVC and dynamic NS connections\n"
	"Show what would be deleted instead of actually deleting\n"
	)
{
	const uint16_t nsei = atoi(argv[0]);
	const char *mode = argv[1];
	int dry_run = argc > 2;
	int delete_bvc = 0;
	int delete_nsvc = 0;
	int counter;

	if (strcmp(mode, "only-bvc") == 0)
		delete_bvc = 1;
	else if (strcmp(mode, "only-nsvc") == 0)
		delete_nsvc = 1;
	else
		delete_bvc = delete_nsvc = 1;

	if (delete_bvc) {
		if (!dry_run)
			counter = gbproxy_cleanup_peers(g_cfg, nsei, 0);
		else {
			struct gbproxy_peer *peer;
			counter = 0;
			llist_for_each_entry(peer, &g_cfg->bts_peers, list) {
				if (peer->nsei != nsei)
					continue;

				vty_out(vty, "BVC: ");
				gbprox_vty_print_peer(vty, peer);
				counter += 1;
			}
		}
		vty_out(vty, "%sDeleted %d BVC%s",
			dry_run ? "Not " : "", counter, VTY_NEWLINE);
	}

	if (delete_nsvc) {
		struct gprs_ns_inst *nsi = g_cfg->nsi;
		struct gprs_nsvc *nsvc, *nsvc2;

		counter = 0;
		llist_for_each_entry_safe(nsvc, nsvc2, &nsi->gprs_nsvcs, list) {
			if (nsvc->nsei != nsei)
				continue;
			if (nsvc->persistent)
				continue;

			if (!dry_run)
				gprs_nsvc_delete(nsvc);
			else
				vty_out(vty, "NS-VC: NSEI %5u, NS-VCI %5u, "
					"remote %s%s",
					nsvc->nsei, nsvc->nsvci,
					gprs_ns_ll_str(nsvc), VTY_NEWLINE);
			counter += 1;
		}
		vty_out(vty, "%sDeleted %d NS-VC%s",
			dry_run ? "Not " : "", counter, VTY_NEWLINE);
	}

	return CMD_SUCCESS;
}

DEFUN(delete_gb_tlli, delete_gb_tlli_cmd,
	"delete-gbproxy-tlli <0-65534> (tlli|imsi|stale) [IDENT]",
	"Delete a GBProxy TLLI entry by NSEI and identification\n"
	"NSEI number\n"
	"Delete entries with a matching TLLI (hex)\n"
	"Delete entries with a matching IMSI\n"
	"Identification to match\n")
{
	const uint16_t nsei = atoi(argv[0]);
	enum {MATCH_TLLI = 't', MATCH_IMSI = 'i', MATCH_STALE = 's'} match;
	uint32_t tlli = 0;
	const char *imsi = NULL;
	struct gbproxy_peer *peer = 0;
	struct gbproxy_tlli_info *tlli_info, *nxt;
	struct gbproxy_patch_state *state;
	char mi_buf[200];
	int found = 0;

	match = argv[1][0];

	switch (match) {
	case MATCH_TLLI:
		if (argc < 2 || !argv[2][0]) {
			vty_out(vty, "%% Missing TLLI%s", VTY_NEWLINE);
			return CMD_WARNING;
		}
		tlli = strtoll(argv[2], NULL, 16);
		break;
	case MATCH_IMSI:
		if (argc < 2 || !argv[2][0]) {
			vty_out(vty, "%% Missing IMSI%s", VTY_NEWLINE);
			return CMD_WARNING;
		}
		imsi = argv[2];
		break;
	default:
		break;
	}

	peer = gbproxy_peer_by_nsei(g_cfg, nsei);
	if (!peer) {
		vty_out(vty, "Didn't find peer with NSEI %d%s",
			nsei, VTY_NEWLINE);
		return CMD_WARNING;
	}

	state = &peer->patch_state;

	if (match == MATCH_STALE) {
		found = gbproxy_remove_stale_tllis(peer, time(NULL));
		if (found)
			vty_out(vty, "Deleted %d stale TLLI%s%s",
				found, found == 1 ? "" : "s", VTY_NEWLINE);
		return CMD_SUCCESS;
	}

	llist_for_each_entry_safe(tlli_info, nxt, &state->enabled_tllis, list) {
		if (match == MATCH_TLLI && tlli_info->tlli.current != tlli)
			continue;

		if (match == MATCH_IMSI) {
			mi_buf[0] = '\0';
			gsm48_mi_to_string(mi_buf, sizeof(mi_buf),
					   tlli_info->mi_data,
					   tlli_info->mi_data_len);

			if (strcmp(mi_buf, imsi) != 0)
				continue;
		}
		vty_out(vty, "Deleting TLLI %08x%s", tlli_info->tlli.current,
			VTY_NEWLINE);
		gbproxy_delete_tlli(peer, tlli_info);
		found += 1;
	}

	if (!found && argc >= 2) {
		vty_out(vty, "Didn't find TLLI entry with %s %s%s",
			argv[1], argv[2], VTY_NEWLINE);
	}

	return CMD_SUCCESS;
}

int gbproxy_vty_init(void)
{
	install_element_ve(&show_gbproxy_cmd);
	install_element_ve(&show_gbproxy_tllis_cmd);

	install_element(ENABLE_NODE, &delete_gb_bvci_cmd);
	install_element(ENABLE_NODE, &delete_gb_nsei_cmd);
	install_element(ENABLE_NODE, &delete_gb_tlli_cmd);

	install_element(CONFIG_NODE, &cfg_gbproxy_cmd);
	install_node(&gbproxy_node, config_write_gbproxy);
	vty_install_default(GBPROXY_NODE);
	install_element(GBPROXY_NODE, &cfg_nsip_sgsn_nsei_cmd);
	install_element(GBPROXY_NODE, &cfg_gbproxy_core_mcc_cmd);
	install_element(GBPROXY_NODE, &cfg_gbproxy_core_mnc_cmd);
	install_element(GBPROXY_NODE, &cfg_gbproxy_core_apn_cmd);
	install_element(GBPROXY_NODE, &cfg_gbproxy_core_apn_match_cmd);
	install_element(GBPROXY_NODE, &cfg_gbproxy_patch_ptmsi_cmd);
	install_element(GBPROXY_NODE, &cfg_gbproxy_tlli_list_max_age_cmd);
	install_element(GBPROXY_NODE, &cfg_gbproxy_tlli_list_max_len_cmd);
	install_element(GBPROXY_NODE, &cfg_gbproxy_no_core_mcc_cmd);
	install_element(GBPROXY_NODE, &cfg_gbproxy_no_core_mnc_cmd);
	install_element(GBPROXY_NODE, &cfg_gbproxy_no_core_apn_cmd);
	install_element(GBPROXY_NODE, &cfg_gbproxy_no_patch_ptmsi_cmd);
	install_element(GBPROXY_NODE, &cfg_gbproxy_tlli_list_no_max_age_cmd);
	install_element(GBPROXY_NODE, &cfg_gbproxy_tlli_list_no_max_len_cmd);
	install_element(GBPROXY_NODE, &cfg_gbproxy_patch_mode_cmd);

	return 0;
}

int gbproxy_parse_config(const char *config_file, struct gbproxy_config *cfg)
{
	int rc;

	g_cfg = cfg;
	rc = vty_read_config_file(config_file, NULL);
	if (rc < 0) {
		fprintf(stderr, "Failed to parse the config file: '%s'\n", config_file);
		return rc;
	}

	return 0;
}