#include <net/if.h>
#include <errno.h>
#include <string.h>

#include <netlink/genl/genl.h>
#include <netlink/genl/family.h>
#include <netlink/genl/ctrl.h>
#include <netlink/msg.h>
#include <netlink/attr.h>

#include "nl80211.h"
#include "iw.h"

typedef struct _any_t {
	union {
		uint32_t as_32;
		uint16_t as_16;
		uint8_t as_8;
	} u;
} _any;

/* describes a mesh parameter */
struct mesh_param_descr {
	const char *name;
	enum nl80211_meshconf_params mesh_param_num;
	int (*nla_put_fn)(struct nl_msg*, int, _any*);
	uint32_t (*parse_fn)(const char*, _any*);
	void (*nla_print_fn)(struct nlattr *);
};

/* utility functions for manipulating and printing u8/u16/u32 values and
 * timesouts. */
static int _my_nla_put_u8(struct nl_msg *n, int mesh_param_num, _any *value)
{
	return nla_put(n, mesh_param_num, sizeof(uint8_t), &value->u.as_8);
}

static int _my_nla_put_u16(struct nl_msg *n, int mesh_param_num, _any *value)
{
	return nla_put(n, mesh_param_num, sizeof(uint16_t), &value->u.as_16);
}

static int _my_nla_put_u32(struct nl_msg *n, int mesh_param_num, _any *value)
{
	return nla_put(n, mesh_param_num, sizeof(uint32_t), &value->u.as_32);
}

static uint32_t _parse_u8(const char *str, _any *ret)
{
	char *endptr = NULL;
	unsigned long int v = strtoul(str, &endptr, 10);
	if (*endptr != '\0')
		return 0xff;
	if (v > 0xff)
		return 0xff;
	ret->u.as_8 = (uint8_t)v;
	return 0;
}

static uint32_t _parse_u8_as_bool(const char *str, _any *ret)
{
	char *endptr = NULL;
	unsigned long int v = strtoul(str, &endptr, 10);
	if (*endptr != '\0')
		return 0x1;
	if (v > 0x1)
		return 0x1;
	ret->u.as_8 = (uint8_t)v;
	return 0;
}

static uint32_t _parse_u16(const char *str, _any *ret)
{
	char *endptr = NULL;
	long int v = strtol(str, &endptr, 10);
	if (*endptr != '\0')
		return 0xffff;
	if ((v < 0) || (v > 0xffff))
		return 0xffff;
	ret->u.as_16 = (uint16_t)v;
	return 0;
}

static uint32_t _parse_u32(const char *str, _any *ret)
{
	char *endptr = NULL;
	long long int v = strtoll(str, &endptr, 10);
	if (*endptr != '\0')
		return 0xffffffff;
	if ((v < 0) || (v > 0xffffffff))
		return 0xffffffff;
	ret->u.as_32 = (uint32_t)v;
	return 0;
}

static void _print_u8(struct nlattr *a)
{
	printf("%d", nla_get_u8(a));
}

static void _print_u16(struct nlattr *a)
{
	printf("%d", nla_get_u16(a));
}

static void _print_u16_timeout(struct nlattr *a)
{
	printf("%d milliseconds", nla_get_u16(a));
}

static void _print_u16_in_TUs(struct nlattr *a)
{
	printf("%d TUs", nla_get_u16(a));
}

static void _print_u32_timeout(struct nlattr *a)
{
	printf("%u milliseconds", nla_get_u32(a));
}

static void _print_u32_in_TUs(struct nlattr *a)
{
	printf("%d TUs", nla_get_u32(a));
}

/* The current mesh parameters */
const static struct mesh_param_descr _mesh_param_descrs[] =
{
	{"mesh_retry_timeout",
	NL80211_MESHCONF_RETRY_TIMEOUT,
	_my_nla_put_u16, _parse_u16, _print_u16_timeout},
	{"mesh_confirm_timeout",
	NL80211_MESHCONF_CONFIRM_TIMEOUT,
	_my_nla_put_u16, _parse_u16, _print_u16_timeout},
	{"mesh_holding_timeout",
	NL80211_MESHCONF_HOLDING_TIMEOUT,
	_my_nla_put_u16, _parse_u16, _print_u16_timeout},
	{"mesh_max_peer_links",
	NL80211_MESHCONF_MAX_PEER_LINKS,
	_my_nla_put_u16, _parse_u16, _print_u16},
	{"mesh_max_retries",
	NL80211_MESHCONF_MAX_RETRIES,
	_my_nla_put_u8, _parse_u8, _print_u8},
	{"mesh_ttl",
	NL80211_MESHCONF_TTL,
	_my_nla_put_u8, _parse_u8, _print_u8},
	{"mesh_auto_open_plinks",
	NL80211_MESHCONF_AUTO_OPEN_PLINKS,
	_my_nla_put_u8, _parse_u8_as_bool, _print_u8},
	{"mesh_hwmp_max_preq_retries",
	NL80211_MESHCONF_HWMP_MAX_PREQ_RETRIES,
	_my_nla_put_u8, _parse_u8, _print_u8},
	{"mesh_path_refresh_time",
	NL80211_MESHCONF_PATH_REFRESH_TIME,
	_my_nla_put_u32, _parse_u32, _print_u32_timeout},
	{"mesh_min_discovery_timeout",
	NL80211_MESHCONF_MIN_DISCOVERY_TIMEOUT,
	_my_nla_put_u16, _parse_u16, _print_u16_timeout},
	{"mesh_hwmp_active_path_timeout",
	NL80211_MESHCONF_HWMP_ACTIVE_PATH_TIMEOUT,
	_my_nla_put_u32, _parse_u32, _print_u32_in_TUs},
	{"mesh_hwmp_preq_min_interval",
	NL80211_MESHCONF_HWMP_PREQ_MIN_INTERVAL,
	_my_nla_put_u16, _parse_u16, _print_u16_in_TUs},
	{"mesh_hwmp_net_diameter_traversal_time",
	NL80211_MESHCONF_HWMP_NET_DIAM_TRVS_TIME,
	_my_nla_put_u16, _parse_u16, _print_u16_in_TUs},
};

static void print_all_mesh_param_descr(void)
{
	int i;

	printf("Possible mesh parameters are:\n");

	for (i = 0; i < ARRAY_SIZE(_mesh_param_descrs); i++)
		printf(" - %s\n", _mesh_param_descrs[i].name);
}

static const struct mesh_param_descr* find_mesh_param(int argc, char **argv,
						const char *action_name)
{
	int i;
	const struct mesh_param_descr *mdescr;

	if (argc < 1) {
		printf("You must specify which mesh parameter to %s.\n",
		       action_name);
		print_all_mesh_param_descr();
		return NULL;
	}

	/* Find out what mesh parameter we want to change. */
	mdescr = NULL;
	for (i = 0; i < ARRAY_SIZE(_mesh_param_descrs); i++) {
		if (!strcmp(_mesh_param_descrs[i].name, argv[0]))
			return _mesh_param_descrs + i;
	}

	if (!mdescr) {
		print_all_mesh_param_descr();
		return NULL;
	}
	return mdescr;
}

/* Setter */
static int set_interface_meshparam(struct nl_cb *cb,
				struct nl_msg *msg,
				int argc, char **argv)
{
	int err;
	uint32_t ret;
	const struct mesh_param_descr *mdescr;
	struct nlattr *container;
	_any any;

	mdescr = find_mesh_param(argc, argv, "change");
	if (!mdescr)
		return 2;
	if (argc != 2) {
		printf("Must specify a value for %s.\n", mdescr->name);
		return 2;
	}

	/* Parse the new value */
	memset(&any, 0, sizeof(_any));
	ret = mdescr->parse_fn(argv[1], &any);
	if (ret != 0) {
		printf("%s must be set to a number "
		       "between 0 and %u\n", mdescr->name, ret);
		return 2;
	}

	/* Construct a netlink message */
	container = nla_nest_start(msg, NL80211_ATTR_MESH_PARAMS);
	if (!container)
		return -ENOBUFS;
	err = mdescr->nla_put_fn(msg, mdescr->mesh_param_num, &any);
	nla_nest_end(msg, container);

	return err;
}

COMMAND(set, mesh_param, "<param> <value>",
	NL80211_CMD_SET_MESH_PARAMS, 0, CIB_NETDEV, set_interface_meshparam);

/* Getter */
static int print_mesh_param_handler(struct nl_msg *msg, void *arg)
{
	const struct mesh_param_descr *mdescr = arg;
	struct nlattr *attrs[NL80211_ATTR_MAX + 1];
	struct nlattr *parent_attr;
	struct nlattr *mesh_params[NL80211_MESHCONF_ATTR_MAX + 1];
	struct genlmsghdr *gnlh = nlmsg_data(nlmsg_hdr(msg));

	/* locate NL80211_ATTR_MESH_PARAMS */
	nla_parse(attrs, NL80211_ATTR_MAX, genlmsg_attrdata(gnlh, 0),
		  genlmsg_attrlen(gnlh, 0), NULL);
	parent_attr = attrs[NL80211_ATTR_MESH_PARAMS];
	if (!parent_attr)
		return -EINVAL;

	/* unpack the mesh parameters */
	if (nla_parse_nested(mesh_params, NL80211_MESHCONF_ATTR_MAX,
				parent_attr, NULL))
		return -EINVAL;

	/* print out the mesh parameter */
	mdescr->nla_print_fn(mesh_params[mdescr->mesh_param_num]);
	printf("\n");
	return NL_SKIP;
}

static int get_interface_meshparam(struct nl_cb *cb,
				struct nl_msg *msg,
				int argc, char **argv)
{
	const struct mesh_param_descr *mdescr;

	mdescr = find_mesh_param(argc, argv, "get");
	if (!mdescr)
		return 2;

	nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM,
		  print_mesh_param_handler, (void *)mdescr);
	return 0;
}

COMMAND(get, mesh_param, "<param>",
	NL80211_CMD_GET_MESH_PARAMS, 0, CIB_NETDEV, get_interface_meshparam);