/**
 * Copyright 2015 (C) Orange
 * <camille.oudot@orange.com>
 *
 * Copyright 2015 (C) Edvina AB
 * <oej@edvina.net>
 *
 * This file is part of Kamailio, a free SIP server.
 *
 * This file 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 file 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 <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>

#include "../../globals.h"
#include "../../sr_module.h"
#include "../../tcp_options.h"
#include "../../dprint.h"
#include "../../mod_fix.h"
#include "../../events.h"

#include "tcpops.h"

MODULE_VERSION

static int  mod_init(void);
static int  child_init(int);
static void mod_destroy(void);
static int w_tcp_keepalive_enable4(sip_msg_t* msg, char* con, char* idle, char *cnt, char *intvl);
static int w_tcp_keepalive_enable3(sip_msg_t* msg, char* idle, char *cnt, char *intvl);
static int w_tcp_keepalive_disable1(sip_msg_t* msg, char* con);
static int w_tcp_keepalive_disable0(sip_msg_t* msg);
static int w_tcpops_set_connection_lifetime2(sip_msg_t* msg, char* con, char* time);
static int w_tcpops_set_connection_lifetime1(sip_msg_t* msg, char* time);
static int w_tcpops_enable_closed_event1(sip_msg_t* msg, char* con, char* foo);
static int w_tcpops_enable_closed_event0(sip_msg_t* msg, char* foo);
static int w_tcp_conid_state(sip_msg_t* msg, char* con, char *p2);
static int w_tcp_conid_alive(sip_msg_t* msg, char* con, char *p2);

static int fixup_numpv(void** param, int param_no);


static cmd_export_t cmds[]={
	{"tcp_keepalive_enable", (cmd_function)w_tcp_keepalive_enable4, 4, fixup_numpv,
		0, ANY_ROUTE},
	{"tcp_keepalive_enable", (cmd_function)w_tcp_keepalive_enable3, 3, fixup_numpv,
		0, REQUEST_ROUTE|ONREPLY_ROUTE},
	{"tcp_keepalive_disable", (cmd_function)w_tcp_keepalive_disable1, 1, fixup_numpv,
		0, ANY_ROUTE},
	{"tcp_keepalive_disable", (cmd_function)w_tcp_keepalive_disable0, 0, 0,
		0, REQUEST_ROUTE|ONREPLY_ROUTE},
	{"tcp_set_connection_lifetime", (cmd_function)w_tcpops_set_connection_lifetime2, 2, fixup_numpv,
		0, ANY_ROUTE},
	{"tcp_set_connection_lifetime", (cmd_function)w_tcpops_set_connection_lifetime1, 1, fixup_numpv,
		0, REQUEST_ROUTE|ONREPLY_ROUTE},
	{"tcp_enable_closed_event", (cmd_function)w_tcpops_enable_closed_event1, 1, fixup_numpv,
		0, ANY_ROUTE},
	{"tcp_enable_closed_event", (cmd_function)w_tcpops_enable_closed_event0, 0, 0,
		0, REQUEST_ROUTE|ONREPLY_ROUTE},
	{"tcp_conid_state", (cmd_function)w_tcp_conid_state, 1, fixup_numpv,
		0, ANY_ROUTE},
	{"tcp_conid_alive", (cmd_function)w_tcp_conid_alive, 1, fixup_numpv,
		0, ANY_ROUTE},
	{0, 0, 0, 0, 0, 0}
};

static param_export_t params[] = {
	{"closed_event",    PARAM_INT,    &tcp_closed_event},
	{0, 0, 0}
};



struct module_exports exports = {
	"tcpops",
	DEFAULT_DLFLAGS, /* dlopen flags */
	cmds,            /* exported functions to config */
	params,          /* exported parameters to config */
	0,               /* exported statistics */
	0,              /* exported MI functions */
	0,        /* exported pseudo-variables */
	0,              /* extra processes */
	mod_init,       /* module initialization function */
	0,              /* response function */
	mod_destroy,    /* destroy function */
	child_init      /* per child init function */
};



/**
 * init module function
 */
static int mod_init(void)
{
	LM_DBG("TCP keepalive module loaded.\n");

	if (tcp_closed_event < 0 || tcp_closed_event > 2) {
		LM_ERR("invalid \"closed_event\" value: %d, must be 0 (disabled), 1 (enabled) or 2 (manual)\n", tcp_closed_event);
		return -1;
	}

	if (tcp_closed_event /* register event only if tcp_closed_event != 0 */
		&& (sr_event_register_cb(SREV_TCP_CLOSED, tcpops_handle_tcp_closed) != 0))
	{
		LM_ERR("problem registering tcpops_handle_tcp_closed call-back\n");
		return -1;
	}

	return 0;
}

/**
 * @brief Initialize async module children
 */
static int child_init(int rank)
{

	return 0;
}
/**
 * destroy module function
 */
static void mod_destroy(void)
{
	LM_DBG("TCP keepalive module unloaded.\n");
}

#define _IVALUE_ERROR(NAME) LM_ERR("invalid parameter '" #NAME "' (must be a number)\n")
#define _IVALUE(NAME)\
int i_##NAME ;\
if(fixup_get_ivalue(msg, (gparam_t*)NAME, &( i_##NAME))!=0)\
{ \
	_IVALUE_ERROR(NAME);\
	return -1;\
}


/**
 *
 */
static int w_tcp_keepalive_enable4(sip_msg_t* msg, char* con, char* idle, char *cnt, char *intvl)
{
	int fd;
	int closefd = 0;

	_IVALUE (con)

	if (msg != NULL && msg->rcv.proto_reserved1 == i_con) {
		if (!tcpops_get_current_fd(msg->rcv.proto_reserved1, &fd)) {
			return -1;
		}
	} else {
		if (!tcpops_acquire_fd_from_tcpmain(i_con, &fd)) {
			return -1;
		}
		closefd = 1;
	}

	_IVALUE (idle)
	_IVALUE (cnt)
	_IVALUE (intvl)

	return tcpops_keepalive_enable(fd, i_idle, i_cnt, i_intvl, closefd);

}

static int w_tcp_keepalive_enable3(sip_msg_t* msg, char* idle, char *cnt, char *intvl)
{
	int fd;

	if (unlikely(msg == NULL)) {
		return -1;
	}

	if(unlikely(msg->rcv.proto != PROTO_TCP && msg->rcv.proto != PROTO_TLS && msg->rcv.proto != PROTO_WS && msg->rcv.proto != PROTO_WSS))
	{
		LM_ERR("the current message does not come from a TCP connection\n");
		return -1;
	}

	if (!tcpops_get_current_fd(msg->rcv.proto_reserved1, &fd)) {
		return -1;
	}

	_IVALUE (idle)
	_IVALUE (cnt)
	_IVALUE (intvl)

	return tcpops_keepalive_enable(fd, i_idle, i_cnt, i_intvl, 0);
}

static int w_tcp_keepalive_disable1(sip_msg_t* msg, char* con)
{
	int fd;
	int closefd = 0;

	_IVALUE (con)

	if (msg != NULL && msg->rcv.proto_reserved1 == i_con) {
		if (!tcpops_get_current_fd(msg->rcv.proto_reserved1, &fd)) {
			return -1;
		}
	} else {
		if (!tcpops_acquire_fd_from_tcpmain(i_con, &fd)) {
			return -1;
		}
		closefd = 1;
	}

	return tcpops_keepalive_disable(fd, closefd);
}

static int w_tcp_keepalive_disable0(sip_msg_t* msg)
{
	int fd;

	if (unlikely(msg == NULL))
		return -1;

	if(unlikely(msg->rcv.proto != PROTO_TCP && msg->rcv.proto != PROTO_TLS && msg->rcv.proto != PROTO_WS && msg->rcv.proto != PROTO_WSS))
	{
		LM_ERR("the current message does not come from a TCP connection\n");
		return -1;
	}

	if (!tcpops_get_current_fd(msg->rcv.proto_reserved1, &fd)) {
		return -1;
	}

	return tcpops_keepalive_disable(fd, 0);
}

/*! \brief Check the state of the TCP connection */
static int w_tcp_conid_state(sip_msg_t* msg, char* conid, char *p2)
{
	struct tcp_connection *s_con;
	int ret = -1;

	_IVALUE (conid)

	if (unlikely((s_con = tcpconn_get(i_conid, 0, 0, 0, 0)) == NULL)) {
		LM_DBG("Connection id %d does not exist.\n", i_conid);
		ret = -1;
		goto done;
	} 
	/* Connection structure exists, now check what Kamailio thinks of it */
	if (s_con->state == S_CONN_OK) {
		/* All is fine, return happily */
		ret = 1;
		goto done;
	}
	if (s_con->state == S_CONN_EOF) {	/* Socket closed or about to close under our feet */
		ret = -2;
		goto done;
	}
	if (s_con->state == S_CONN_ERROR) {	/* Error on read/write - will close soon */
		ret = -3;
		goto done;
	}
	if (s_con->state == S_CONN_BAD) {	/* Unknown state */
		ret = -4;
		goto done;
	}
	if (s_con->state == S_CONN_ACCEPT) {	/* Incoming connection to be set up */
		ret = 2;
		goto done;
	}
	if (s_con->state == S_CONN_CONNECT) {	/* Outbound connection moving to S_CONN_OK */
		ret = 3;
		goto done;
	}
	/* Wonder what state we're in here */
	LM_DBG("Connection id %d is in unexpected state %d - assuming ok.\n", i_conid, s_con->flags);

	/* Good connection */
	ret = 1;
done:
	if(s_con) tcpconn_put(s_con);
	return ret;
}

/*! \brief A simple check to see if a connection is alive or not,
	avoiding all the various connection states
 */
static int w_tcp_conid_alive(sip_msg_t* msg, char* conid, char *p2)
{
	int ret = w_tcp_conid_state(msg, conid, p2);
	if (ret >= 1) {
		return 1;	/* TRUE */
	} 
	/* We have some kind of problem */
	return -1;
}

static int w_tcpops_set_connection_lifetime2(sip_msg_t* msg, char* conid, char* time)
{
	struct tcp_connection *s_con;
	int ret = -1;

	_IVALUE (conid)
	_IVALUE (time)

	if (unlikely((s_con = tcpconn_get(i_conid, 0, 0, 0, 0)) == NULL)) {
		LM_ERR("invalid connection id %d, (must be a TCP conid)\n", i_conid);
		return 0;
	} else {
		ret = tcpops_set_connection_lifetime(s_con, i_time);
		tcpconn_put(s_con);
	}
	return ret;
}


static int w_tcpops_set_connection_lifetime1(sip_msg_t* msg, char* time)
{
	struct tcp_connection *s_con;
	int ret = -1;

	_IVALUE (time)

	if(unlikely(msg->rcv.proto != PROTO_TCP && msg->rcv.proto != PROTO_TLS && msg->rcv.proto != PROTO_WS && msg->rcv.proto != PROTO_WSS))
	{
		LM_ERR("the current message does not come from a TCP connection\n");
		return -1;
	}

	if (unlikely((s_con = tcpconn_get(msg->rcv.proto_reserved1, 0, 0, 0, 0)) == NULL)) {
		return -1;
	} else {
		ret = tcpops_set_connection_lifetime(s_con, i_time);
		tcpconn_put(s_con);
	}
	return ret;
}

static int w_tcpops_enable_closed_event1(sip_msg_t* msg, char* conid, char* foo)
{
	struct tcp_connection *s_con;

	_IVALUE (conid)

	if (unlikely((s_con = tcpconn_get(i_conid, 0, 0, 0, 0)) == NULL)) {
		LM_ERR("invalid connection id %d, (must be a TCP conid)\n", i_conid);
		return 0;
	} else {
		s_con->flags |= F_CONN_CLOSE_EV;
		tcpconn_put(s_con);
	}
	return 1;
}


static int w_tcpops_enable_closed_event0(sip_msg_t* msg, char* foo)
{
	struct tcp_connection *s_con;

	if (unlikely(tcp_closed_event != 2)) {
		LM_WARN("tcp_enable_closed_event() can only be used if"
				" the \"closed_event\" modparam is set to 2\n");
		return -1;
	}

	if(unlikely(msg->rcv.proto != PROTO_TCP && msg->rcv.proto != PROTO_TLS && msg->rcv.proto != PROTO_WS && msg->rcv.proto != PROTO_WSS))
	{
		LM_ERR("the current message does not come from a TCP connection\n");
		return -1;
	}

	if (unlikely((s_con = tcpconn_get(msg->rcv.proto_reserved1, 0, 0, 0, 0)) == NULL)) {
		return -1;
	} else {
		s_con->flags |= F_CONN_CLOSE_EV;
		tcpconn_put(s_con);
	}
	return 1;
}

/**
 *
 */
static int fixup_numpv(void** param, int param_no)
{
	return fixup_igp_null(param, 1);
}