/*
** Zabbix
** Copyright (C) 2001-2021 Zabbix SIA
**
** 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, write to the Free Software
** Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
**/

#include "common.h"
#include "sysinfo.h"
#include "zbxjson.h"
#include "log.h"

static struct nlist kernel_symbols[] =
{
	{"_ifnet", N_UNDF, 0, 0, 0},
	{"_tcbtable", N_UNDF, 0, 0, 0},
	{NULL, 0, 0, 0, 0}
};

#define IFNET_ID 0

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)
{
	struct ifnet_head	head;
	struct ifnet		*ifp;
	struct ifnet		v;

	kvm_t	*kp;
	int	len = 0;
	int	ret = SYSINFO_RET_FAIL;

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

	if (NULL == (kp = kvm_open(NULL, NULL, NULL, O_RDONLY, NULL))) /* requires root privileges */
	{
		*error = zbx_strdup(NULL, "Cannot obtain a descriptor to access kernel virtual memory.");
		return FAIL;
	}

	if (N_UNDF == kernel_symbols[IFNET_ID].n_type)
		if (0 != kvm_nlist(kp, &kernel_symbols[0]))
			kernel_symbols[IFNET_ID].n_type = N_UNDF;

	if (N_UNDF != kernel_symbols[IFNET_ID].n_type)
	{
		len = sizeof(struct ifnet_head);

		if (kvm_read(kp, kernel_symbols[IFNET_ID].n_value, &head, len) >= len)
		{
			len = sizeof(struct ifnet);

			/* if_ibytes;		total number of octets received */
			/* if_ipackets;		packets received on interface */
			/* if_ierrors;		input errors on interface */
			/* if_iqdrops;		dropped on input, this interface */
			/* if_obytes;		total number of octets sent */
			/* if_opackets;		packets sent on interface */
			/* if_oerrors;		output errors on interface */
			/* if_collisions;	collisions on csma interfaces */

			if (ibytes)
				*ibytes = 0;
			if (ipackets)
				*ipackets = 0;
			if (ierrors)
				*ierrors = 0;
			if (idropped)
				*idropped = 0;
			if (obytes)
				*obytes = 0;
			if (opackets)
				*opackets = 0;
			if (oerrors)
				*oerrors = 0;
			if (tbytes)
				*tbytes = 0;
			if (tpackets)
				*tpackets = 0;
			if (terrors)
				*terrors = 0;
			if (icollisions)
				*icollisions = 0;

			for (ifp = head.tqh_first; ifp; ifp = v.if_list.tqe_next)
			{
				if (kvm_read(kp, (u_long)ifp, &v, len) < len)
					break;

				if (0 == strcmp(if_name, v.if_xname))
				{
					if (ibytes)
						*ibytes += v.if_ibytes;
					if (ipackets)
						*ipackets += v.if_ipackets;
					if (ierrors)
						*ierrors += v.if_ierrors;
					if (idropped)
						*idropped += v.if_iqdrops;
					if (obytes)
						*obytes += v.if_obytes;
					if (opackets)
						*opackets += v.if_opackets;
					if (oerrors)
						*oerrors += v.if_oerrors;
					if (tbytes)
						*tbytes += v.if_ibytes + v.if_obytes;
					if (tpackets)
						*tpackets += v.if_ipackets + v.if_opackets;
					if (terrors)
						*terrors += v.if_ierrors + v.if_oerrors;
					if (icollisions)
						*icollisions += v.if_collisions;
					ret = SYSINFO_RET_OK;
				}
			}
		}
	}

	kvm_close(kp);

	if (SYSINFO_RET_FAIL == ret)
	{
		*error = zbx_strdup(NULL, "Cannot find information for this network interface.");
		return SYSINFO_RET_FAIL;
	}

	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_init(&j, ZBX_JSON_STAT_BUF_LEN);

	zbx_json_addarray(&j, ZBX_PROTO_TAG_DATA);

	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;
}