/*
** Copyright (C) 2001-2024 Zabbix SIA
**
** 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, version 3.
**
** 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 <https://www.gnu.org/licenses/>.
**/

#include <net/route.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <net/if_types.h>

#include "zbxsysinfo.h"
#include "../sysinfo.h"

#include "zbxjson.h"

static void	get_rtaddrs(int addrs, struct sockaddr *sa, struct sockaddr **rti_info)
{
	int i;

	for (i = 0; i < RTAX_MAX; i++)
	{
		if (addrs & (1 << i))
		{
			rti_info[i] = sa;
			sa = (struct sockaddr *)((char *)(sa) + RT_ROUNDUP(sa->sa_len));
		}
		else
			rti_info[i] = NULL;
	}
}

static int	get_ifdata(const char *if_name,
				zbx_uint64_t *ibytes, zbx_uint64_t *ipackets,
				zbx_uint64_t *ierrors, zbx_uint64_t *idropped,
				zbx_uint64_t *obytes, zbx_uint64_t *opackets,
				zbx_uint64_t *oerrors, zbx_uint64_t *tbytes,
				zbx_uint64_t *tpackets, zbx_uint64_t *terrors,
				zbx_uint64_t *icollisions, char **error)
{
	static size_t		olen;
	static char		*buf = NULL;
	int			ret = SYSINFO_RET_FAIL;
	int			mib[6] = { CTL_NET, AF_ROUTE, 0, 0, NET_RT_IFLIST, 0 };
	size_t			len;
	char			name[IFNAMSIZ + 1];
	char			*next, *end, *cp;
	struct if_msghdr	*ifm;
	struct rt_msghdr	*rtm;
	struct if_data		*ifd = NULL;
	struct sockaddr		*sa, *rti_info[RTAX_MAX];
	struct sockaddr_dl	*sdl;

	if (NULL == if_name || '\0' == *if_name)
	{
		*error = zbx_strdup(NULL, "Network interface name cannot be empty.");
		return FAIL;
	}

	if (-1 == sysctl(mib, 6, NULL, &len, NULL, 0))
		return FAIL;

	if (len > olen)
	{
		zbx_free(buf);

		if (NULL == (buf = zbx_malloc(buf, len)))
		{
			*error = zbx_strdup(NULL, "sysctl get-length failed");
			return FAIL;
		}

		olen = len;
	}

	if (-1 == sysctl(mib, 6, buf, &len, NULL, 0))
	{
		*error = zbx_strdup(NULL, "sysctl get-if-list failed");
		return FAIL;
	}

	for (next = buf, end = buf + len; next < end; next += rtm->rtm_msglen)
	{
		rtm = (struct rt_msghdr *)next;
		if (RTM_VERSION != rtm->rtm_version)
			continue;

		if (RTM_IFINFO != rtm->rtm_type)
			continue;

		ifm = (struct if_msghdr *)next;
		ifd = &ifm->ifm_data;
		sa = (struct sockaddr *)(ifm + 1);
		get_rtaddrs(ifm->ifm_addrs, sa, rti_info);

		sdl = (struct sockaddr_dl *)rti_info[RTAX_IFP];

		memset(name, 0, sizeof(name));
		if (IFNAMSIZ <= sdl->sdl_nlen)
			memcpy(name, sdl->sdl_data, IFNAMSIZ - 1);
		else if (0 < sdl->sdl_nlen)
			memcpy(name, sdl->sdl_data, sdl->sdl_nlen);

		if (0 != strcmp(name, if_name))
			continue;

		/*
		 * ifi_ibytes		total number of octets received
		 * ifi_ipackets		packets received on interface
		 * ifi_ierrors		input errors on interface
		 * ifi_iqdrops		dropped on input, this interface
		 * ifi_obytes		total number of octets sent
		 * ifi_opackets		packets sent on interface
		 * ifi_oerrors		output errors on interface
		 * ifi_collisions	collisions on csma interfaces
		 */

		if (ibytes)
			*ibytes = ifd->ifi_ibytes;
		if (ipackets)
			*ipackets = ifd->ifi_ipackets;
		if (ierrors)
			*ierrors = ifd->ifi_ierrors;
		if (idropped)
			*idropped = ifd->ifi_iqdrops;
		if (obytes)
			*obytes = ifd->ifi_obytes;
		if (opackets)
			*opackets = ifd->ifi_opackets;
		if (oerrors)
			*oerrors = ifd->ifi_oerrors;
		if (tbytes)
			*tbytes = ifd->ifi_ibytes + ifd->ifi_obytes;
		if (tpackets)
			*tpackets = ifd->ifi_ipackets + ifd->ifi_opackets;
		if (terrors)
			*terrors = ifd->ifi_ierrors + ifd->ifi_oerrors;
		if (icollisions)
			*icollisions = ifd->ifi_collisions;

		ret = SYSINFO_RET_OK;
	}

	if (SYSINFO_RET_OK != ret)
		*error = zbx_strdup(NULL, "Cannot find information for this network interface.");

	return ret;
}

int	net_if_in(AGENT_REQUEST *request, AGENT_RESULT *result)
{
	char		*if_name, *mode, *error;
	zbx_uint64_t	ibytes, ipackets, ierrors, idropped;

	if (2 < request->nparam)
	{
		SET_MSG_RESULT(result, zbx_strdup(NULL, "Too many parameters."));
		return SYSINFO_RET_FAIL;
	}

	if_name = get_rparam(request, 0);
	mode = get_rparam(request, 1);

	if (SYSINFO_RET_OK != get_ifdata(if_name, &ibytes, &ipackets, &ierrors, &idropped, NULL, NULL, NULL, NULL, NULL,
			NULL, NULL, &error))
	{
		SET_MSG_RESULT(result, error);
		return SYSINFO_RET_FAIL;
	}

	if (NULL == mode || '\0' == *mode || 0 == strcmp(mode, "bytes"))	/* default parameter */
		SET_UI64_RESULT(result, ibytes);
	else if (0 == strcmp(mode, "packets"))
		SET_UI64_RESULT(result, ipackets);
	else if (0 == strcmp(mode, "errors"))
		SET_UI64_RESULT(result, ierrors);
	else if (0 == strcmp(mode, "dropped"))
		SET_UI64_RESULT(result, idropped);
	else
	{
		SET_MSG_RESULT(result, zbx_strdup(NULL, "Invalid second parameter."));
		return SYSINFO_RET_FAIL;
	}

	return SYSINFO_RET_OK;
}

int	net_if_out(AGENT_REQUEST *request, AGENT_RESULT *result)
{
	char		*if_name, *mode, *error;
	zbx_uint64_t	obytes, opackets, oerrors;

	if (2 < request->nparam)
	{
		SET_MSG_RESULT(result, zbx_strdup(NULL, "Too many parameters."));
		return SYSINFO_RET_FAIL;
	}

	if_name = get_rparam(request, 0);
	mode = get_rparam(request, 1);

	if (SYSINFO_RET_OK != get_ifdata(if_name, NULL, NULL, NULL, NULL, &obytes, &opackets, &oerrors, NULL, NULL,
			NULL, NULL, &error))
	{
		SET_MSG_RESULT(result, error);
		return SYSINFO_RET_FAIL;
	}

	if (NULL == mode || '\0' == *mode || 0 == strcmp(mode, "bytes"))	/* default parameter */
		SET_UI64_RESULT(result, obytes);
	else if (0 == strcmp(mode, "packets"))
		SET_UI64_RESULT(result, opackets);
	else if (0 == strcmp(mode, "errors"))
		SET_UI64_RESULT(result, oerrors);
	else
	{
		SET_MSG_RESULT(result, zbx_strdup(NULL, "Invalid second parameter."));
		return SYSINFO_RET_FAIL;
	}

	return SYSINFO_RET_OK;
}

int	net_if_total(AGENT_REQUEST *request, AGENT_RESULT *result)
{
	char		*if_name, *mode, *error;
	zbx_uint64_t	tbytes, tpackets, terrors;

	if (2 < request->nparam)
	{
		SET_MSG_RESULT(result, zbx_strdup(NULL, "Too many parameters."));
		return SYSINFO_RET_FAIL;
	}

	if_name = get_rparam(request, 0);
	mode = get_rparam(request, 1);

	if (SYSINFO_RET_OK != get_ifdata(if_name, NULL, NULL, NULL, NULL, NULL, NULL, NULL, &tbytes, &tpackets,
			&terrors, NULL, &error))
	{
		SET_MSG_RESULT(result, error);
		return SYSINFO_RET_FAIL;
	}

	if (NULL == mode || '\0' == *mode || 0 == strcmp(mode, "bytes"))	/* default parameter */
		SET_UI64_RESULT(result, tbytes);
	else if (0 == strcmp(mode, "packets"))
		SET_UI64_RESULT(result, tpackets);
	else if (0 == strcmp(mode, "errors"))
		SET_UI64_RESULT(result, terrors);
	else
	{
		SET_MSG_RESULT(result, zbx_strdup(NULL, "Invalid second parameter."));
		return SYSINFO_RET_FAIL;
	}

	return SYSINFO_RET_OK;
}

int	net_if_collisions(AGENT_REQUEST *request, AGENT_RESULT *result)
{
	char		*if_name, *error;
	zbx_uint64_t	icollisions;

	if (1 < request->nparam)
	{
		SET_MSG_RESULT(result, zbx_strdup(NULL, "Too many parameters."));
		return SYSINFO_RET_FAIL;
	}

	if_name = get_rparam(request, 0);

	if (SYSINFO_RET_OK != get_ifdata(if_name, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
			NULL, &icollisions, &error))
	{
		SET_MSG_RESULT(result, error);
		return SYSINFO_RET_FAIL;
	}

	SET_UI64_RESULT(result, icollisions);

	return SYSINFO_RET_OK;
}

int	net_if_discovery(AGENT_REQUEST *request, AGENT_RESULT *result)
{
	int			i;
	struct zbx_json		j;
	struct if_nameindex	*interfaces;

	if (NULL == (interfaces = if_nameindex()))
	{
		SET_MSG_RESULT(result, zbx_dsprintf(NULL, "Cannot obtain system information: %s", zbx_strerror(errno)));
		return SYSINFO_RET_FAIL;
	}

	zbx_json_initarray(&j, ZBX_JSON_STAT_BUF_LEN);

	for (i = 0; 0 != interfaces[i].if_index; i++)
	{
		zbx_json_addobject(&j, NULL);
		zbx_json_addstring(&j, "{#IFNAME}", interfaces[i].if_name, ZBX_JSON_TYPE_STRING);
		zbx_json_close(&j);
	}

	zbx_json_close(&j);

	SET_STR_RESULT(result, strdup(j.buffer));

	zbx_json_free(&j);

	if_freenameindex(interfaces);

	return SYSINFO_RET_OK;
}