/*
  Copyright (c) 2016-2019, Matthias Schiffer <mschiffer@universe-factory.net>
  All rights reserved.

  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions are met:

    1. Redistributions of source code must retain the above copyright notice,
       this list of conditions and the following disclaimer.
    2. Redistributions in binary form must reproduce the above copyright notice,
       this list of conditions and the following disclaimer in the documentation
       and/or other materials provided with the distribution.

  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

#include "respondd-common.h"

#include <batadv-genl.h>

#include <json-c/json.h>

#include <netlink/netlink.h>
#include <netlink/genl/genl.h>

#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <net/if.h>
#include <sys/types.h>
#include <sys/ioctl.h>

#include <linux/ethtool.h>
#include <linux/sockios.h>


#define MAX_INACTIVITY 60000


struct clients_netlink_opts {
	size_t clients;
	struct batadv_nlquery_opts query_opts;
};

struct gw_netlink_opts {
	struct json_object *obj;
	struct batadv_nlquery_opts query_opts;
};


static const enum batadv_nl_attrs gateways_mandatory[] = {
	BATADV_ATTR_ORIG_ADDRESS,
	BATADV_ATTR_ROUTER,
};

static int parse_gw_list_netlink_cb(struct nl_msg *msg, void *arg)
{
	struct nlattr *attrs[BATADV_ATTR_MAX+1];
	struct nlmsghdr *nlh = nlmsg_hdr(msg);
	struct batadv_nlquery_opts *query_opts = arg;
	struct genlmsghdr *ghdr;
	uint8_t *orig;
	uint8_t *router;
	struct gw_netlink_opts *opts;
	char addr[18];

	opts = batadv_container_of(query_opts, struct gw_netlink_opts,
				   query_opts);

	if (!genlmsg_valid_hdr(nlh, 0))
		return NL_OK;

	ghdr = nlmsg_data(nlh);

	if (ghdr->cmd != BATADV_CMD_GET_GATEWAYS)
		return NL_OK;

	if (nla_parse(attrs, BATADV_ATTR_MAX, genlmsg_attrdata(ghdr, 0),
		      genlmsg_len(ghdr), batadv_genl_policy))
		return NL_OK;

	if (batadv_genl_missing_attrs(attrs, gateways_mandatory,
				      BATADV_ARRAY_SIZE(gateways_mandatory)))
		return NL_OK;

	if (!attrs[BATADV_ATTR_FLAG_BEST])
		return NL_OK;

	orig = nla_data(attrs[BATADV_ATTR_ORIG_ADDRESS]);
	router = nla_data(attrs[BATADV_ATTR_ROUTER]);

	sprintf(addr, "%02x:%02x:%02x:%02x:%02x:%02x",
		orig[0], orig[1], orig[2], orig[3], orig[4], orig[5]);

	json_object_object_add(opts->obj, "gateway", json_object_new_string(addr));

	sprintf(addr, "%02x:%02x:%02x:%02x:%02x:%02x",
		router[0], router[1], router[2], router[3], router[4], router[5]);

	json_object_object_add(opts->obj, "gateway_nexthop", json_object_new_string(addr));

	return NL_STOP;
}

static void add_gateway(struct json_object *obj) {
	struct gw_netlink_opts opts = {
		.obj = obj,
		.query_opts = {
			.err = 0,
		},
	};

	batadv_genl_query("bat0", BATADV_CMD_GET_GATEWAYS,
			  parse_gw_list_netlink_cb, NLM_F_DUMP,
			  &opts.query_opts);
}

static inline bool ethtool_ioctl(int fd, struct ifreq *ifr, void *data) {
	ifr->ifr_data = data;

	return (ioctl(fd, SIOCETHTOOL, ifr) >= 0);
}

static uint32_t ethtool_get_stats_length(int fd, struct ifreq *ifr) {
	struct {
		struct ethtool_sset_info info;
		uint32_t buf;
	} sset = {};

	sset.info.cmd = ETHTOOL_GSSET_INFO;
	sset.info.sset_mask = (uint64_t)1 << ETH_SS_STATS;

	if (!ethtool_ioctl(fd, ifr, &sset.info))
		return 0;

	return sset.info.sset_mask ? sset.info.data[0] : 0;
}

static struct ethtool_gstrings * ethtool_get_stats_strings(int fd, struct ifreq *ifr) {
	uint32_t n_stats = ethtool_get_stats_length(fd, ifr);

	if (!n_stats)
		return NULL;

	struct ethtool_gstrings *strings = calloc(1, sizeof(*strings) + n_stats * ETH_GSTRING_LEN);

	strings->cmd = ETHTOOL_GSTRINGS;
	strings->string_set = ETH_SS_STATS;
	strings->len = n_stats;

	if (!ethtool_ioctl(fd, ifr, strings)) {
		free(strings);
		return NULL;
	}

	return strings;
}


static struct json_object * get_traffic(void) {
	struct ethtool_gstrings *strings = NULL;
	struct ethtool_stats *stats = NULL;

	struct ifreq ifr = {};
	strncpy(ifr.ifr_name, "bat0", IF_NAMESIZE);

	struct json_object *ret = NULL;

	int fd = socket(AF_INET, SOCK_DGRAM, 0);
	if (fd < 0)
		return NULL;

	strings = ethtool_get_stats_strings(fd, &ifr);
	if (!strings)
		goto out;

	stats = calloc(1, sizeof(struct ethtool_stats) + strings->len * sizeof(uint64_t));
	stats->cmd = ETHTOOL_GSTATS;
	stats->n_stats = strings->len;

	if (!ethtool_ioctl(fd, &ifr, stats))
		goto out;

	struct json_object *rx = json_object_new_object();
	struct json_object *tx = json_object_new_object();
	struct json_object *forward = json_object_new_object();
	struct json_object *mgmt_rx = json_object_new_object();
	struct json_object *mgmt_tx = json_object_new_object();

	size_t i;
	for (i = 0; i < strings->len; i++) {
		if (!strncmp((const char*)&strings->data[i * ETH_GSTRING_LEN], "rx", ETH_GSTRING_LEN))
			json_object_object_add(rx, "packets", json_object_new_int64(stats->data[i]));
		else if (!strncmp((const char*)&strings->data[i * ETH_GSTRING_LEN], "rx_bytes", ETH_GSTRING_LEN))
			json_object_object_add(rx, "bytes", json_object_new_int64(stats->data[i]));
		else if (!strncmp((const char*)&strings->data[i * ETH_GSTRING_LEN], "tx", ETH_GSTRING_LEN))
			json_object_object_add(tx, "packets", json_object_new_int64(stats->data[i]));
		else if (!strncmp((const char*)&strings->data[i * ETH_GSTRING_LEN], "tx_dropped", ETH_GSTRING_LEN))
			json_object_object_add(tx, "dropped", json_object_new_int64(stats->data[i]));
		else if (!strncmp((const char*)&strings->data[i * ETH_GSTRING_LEN], "tx_bytes", ETH_GSTRING_LEN))
			json_object_object_add(tx, "bytes", json_object_new_int64(stats->data[i]));
		else if (!strncmp((const char*)&strings->data[i * ETH_GSTRING_LEN], "forward", ETH_GSTRING_LEN))
			json_object_object_add(forward, "packets", json_object_new_int64(stats->data[i]));
		else if (!strncmp((const char*)&strings->data[i * ETH_GSTRING_LEN], "forward_bytes", ETH_GSTRING_LEN))
			json_object_object_add(forward, "bytes", json_object_new_int64(stats->data[i]));
		else if (!strncmp((const char*)&strings->data[i * ETH_GSTRING_LEN], "mgmt_rx", ETH_GSTRING_LEN))
			json_object_object_add(mgmt_rx, "packets", json_object_new_int64(stats->data[i]));
		else if (!strncmp((const char*)&strings->data[i * ETH_GSTRING_LEN], "mgmt_rx_bytes", ETH_GSTRING_LEN))
			json_object_object_add(mgmt_rx, "bytes", json_object_new_int64(stats->data[i]));
		else if (!strncmp((const char*)&strings->data[i * ETH_GSTRING_LEN], "mgmt_tx", ETH_GSTRING_LEN))
			json_object_object_add(mgmt_tx, "packets", json_object_new_int64(stats->data[i]));
		else if (!strncmp((const char*)&strings->data[i * ETH_GSTRING_LEN], "mgmt_tx_bytes", ETH_GSTRING_LEN))
			json_object_object_add(mgmt_tx, "bytes", json_object_new_int64(stats->data[i]));
	}

	ret = json_object_new_object();
	json_object_object_add(ret, "rx", rx);
	json_object_object_add(ret, "tx", tx);
	json_object_object_add(ret, "forward", forward);
	json_object_object_add(ret, "mgmt_rx", mgmt_rx);
	json_object_object_add(ret, "mgmt_tx", mgmt_tx);

 out:
	free(stats);
	free(strings);
	close(fd);
	return ret;
}

static const enum batadv_nl_attrs clients_mandatory[] = {
	BATADV_ATTR_TT_FLAGS,
	/* Entries without the BATADV_TT_CLIENT_NOPURGE flag do not have a
	 * BATADV_ATTR_LAST_SEEN_MSECS attribute. We can still make this attr
	 * mandatory here, as entries without BATADV_TT_CLIENT_NOPURGE are
	 * ignored anyways.
	 */
	BATADV_ATTR_LAST_SEEN_MSECS,
};

static int parse_clients_list_netlink_cb(struct nl_msg *msg, void *arg)
{
	struct nlattr *attrs[BATADV_ATTR_MAX+1];
	struct nlmsghdr *nlh = nlmsg_hdr(msg);
	struct batadv_nlquery_opts *query_opts = arg;
	struct genlmsghdr *ghdr;
	struct clients_netlink_opts *opts;
	uint32_t flags, lastseen;

	opts = batadv_container_of(query_opts, struct clients_netlink_opts,
				   query_opts);

	if (!genlmsg_valid_hdr(nlh, 0))
		return NL_OK;

	ghdr = nlmsg_data(nlh);

	if (ghdr->cmd != BATADV_CMD_GET_TRANSTABLE_LOCAL)
		return NL_OK;

	if (nla_parse(attrs, BATADV_ATTR_MAX, genlmsg_attrdata(ghdr, 0),
		      genlmsg_len(ghdr), batadv_genl_policy))
		return NL_OK;

	if (batadv_genl_missing_attrs(attrs, clients_mandatory,
				      BATADV_ARRAY_SIZE(clients_mandatory)))
		return NL_OK;

	flags = nla_get_u32(attrs[BATADV_ATTR_TT_FLAGS]);

	if (flags & (BATADV_TT_CLIENT_NOPURGE))
		return NL_OK;

	lastseen = nla_get_u32(attrs[BATADV_ATTR_LAST_SEEN_MSECS]);
	if (lastseen > MAX_INACTIVITY)
		return NL_OK;

	opts->clients++;

	return NL_OK;
}

static struct json_object * get_clients(void) {
	struct clients_netlink_opts opts = {
		.clients = 0,
		.query_opts = {
			.err = 0,
		},
	};

	batadv_genl_query("bat0", BATADV_CMD_GET_TRANSTABLE_LOCAL,
			  parse_clients_list_netlink_cb, NLM_F_DUMP,
			  &opts.query_opts);

	struct json_object *ret = json_object_new_object();

	json_object_object_add(ret, "total", json_object_new_int(opts.clients));

	return ret;
}

struct json_object * respondd_provider_statistics(void) {
	struct json_object *ret = json_object_new_object();

	json_object_object_add(ret, "clients", get_clients());
	json_object_object_add(ret, "traffic", get_traffic());

	add_gateway(ret);

	return ret;
}