/* imtcp.c
 * This is the implementation of the TCP input module.
 *
 * File begun on 2007-12-21 by RGerhards (extracted from syslogd.c)
 *
 * Copyright 2007, 2009 Rainer Gerhards and Adiscon GmbH.
 *
 * This file is part of rsyslog.
 *
 * Rsyslog 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 3 of the License, or
 * (at your option) any later version.
 *
 * Rsyslog 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 Rsyslog.  If not, see <http://www.gnu.org/licenses/>.
 *
 * A copy of the GPL can be found in the file "COPYING" in this distribution.
 */

/* This note shall explain the calling sequence while we do not have
 * have full RainerScript support for (TLS) sender authentication:
 *
 * imtcp --> tcpsrv --> netstrms (this sequence stored pPermPeers in netstrms class)
 * then a callback (doOpenLstnSocks) into imtcp happens, which in turn calls
 * into tcpsrv.create_tcp_socket(),
 * which calls into netstrm.LstnInit(), which receives a pointer to netstrms obj
 * which calls into the driver function LstnInit (again, netstrms obj passed)
 * which finally calls back into netstrms obj's get functions to obtain the auth
 * parameters and then applies them to the driver object instance
 *
 * rgerhards, 2008-05-19
 */

#include "config.h"
#include <stdlib.h>
#include <assert.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <stdarg.h>
#include <ctype.h>
#include <netinet/in.h>
#include <netdb.h>
#include <sys/types.h>
#include <sys/socket.h>
#if HAVE_FCNTL_H
#include <fcntl.h>
#endif
#include "rsyslog.h"
#include "dirty.h"
#include "cfsysline.h"
#include "module-template.h"
#include "unicode-helper.h"
#include "net.h"
#include "netstrm.h"
#include "errmsg.h"
#include "tcpsrv.h"
#include "net.h" /* for permittedPeers, may be removed when this is removed */

MODULE_TYPE_INPUT

/* static data */
DEF_IMOD_STATIC_DATA
DEFobjCurrIf(tcpsrv)
DEFobjCurrIf(tcps_sess)
DEFobjCurrIf(net)
DEFobjCurrIf(netstrm)
DEFobjCurrIf(errmsg)

/* Module static data */
static tcpsrv_t *pOurTcpsrv = NULL;  /* our TCP server(listener) TODO: change for multiple instances */
static permittedPeers_t *pPermPeersRoot = NULL;


/* config settings */
static int iTCPSessMax = 200; /* max number of sessions */
static int iStrmDrvrMode = 0; /* mode for stream driver, driver-dependent (0 mostly means plain tcp) */
static int iAddtlFrameDelim = TCPSRV_NO_ADDTL_DELIMITER; /* addtl frame delimiter, e.g. for netscreen, default none */
static uchar *pszStrmDrvrAuthMode = NULL; /* authentication mode to use */
static uchar *pszInputName = NULL; /* value for inputname property, NULL is OK and handled by core engine */


/* callbacks */
/* this shall go into a specific ACL module! */
static int
isPermittedHost(struct sockaddr *addr, char *fromHostFQDN, void __attribute__((unused)) *pUsrSrv,
	        void __attribute__((unused)) *pUsrSess)
{
	return net.isAllowedSender(UCHAR_CONSTANT("TCP"), addr, fromHostFQDN);
}


static rsRetVal
doOpenLstnSocks(tcpsrv_t *pSrv)
{
	ISOBJ_TYPE_assert(pSrv, tcpsrv);
	return tcpsrv.create_tcp_socket(pSrv);
}


static rsRetVal
doRcvData(tcps_sess_t *pSess, char *buf, size_t lenBuf, ssize_t *piLenRcvd)
{
	DEFiRet;
	assert(pSess != NULL);
	assert(piLenRcvd != NULL);

	*piLenRcvd = lenBuf;
	CHKiRet(netstrm.Rcv(pSess->pStrm, (uchar*) buf, piLenRcvd));
finalize_it:
	RETiRet;
}

static rsRetVal
onRegularClose(tcps_sess_t *pSess)
{
	DEFiRet;
	assert(pSess != NULL);

	/* process any incomplete frames left over */
	tcps_sess.PrepareClose(pSess);
	/* Session closed */
	tcps_sess.Close(pSess);
	RETiRet;
}


static rsRetVal
onErrClose(tcps_sess_t *pSess)
{
	DEFiRet;
	assert(pSess != NULL);

	tcps_sess.Close(pSess);
	RETiRet;
}

/* ------------------------------ end callbacks ------------------------------ */


/* set permitted peer -- rgerhards, 2008-05-19
 */
static rsRetVal
setPermittedPeer(void __attribute__((unused)) *pVal, uchar *pszID)
{
	DEFiRet;
	CHKiRet(net.AddPermittedPeer(&pPermPeersRoot, pszID));
	free(pszID); /* no longer needed, but we need to free as of interface def */
finalize_it:
	RETiRet;
}


static rsRetVal addTCPListener(void __attribute__((unused)) *pVal, uchar *pNewVal)
{
	DEFiRet;

	if(pOurTcpsrv == NULL) {
		CHKiRet(tcpsrv.Construct(&pOurTcpsrv));
		CHKiRet(tcpsrv.SetSessMax(pOurTcpsrv, iTCPSessMax));
		CHKiRet(tcpsrv.SetCBIsPermittedHost(pOurTcpsrv, isPermittedHost));
		CHKiRet(tcpsrv.SetCBRcvData(pOurTcpsrv, doRcvData));
		CHKiRet(tcpsrv.SetCBOpenLstnSocks(pOurTcpsrv, doOpenLstnSocks));
		CHKiRet(tcpsrv.SetCBOnRegularClose(pOurTcpsrv, onRegularClose));
		CHKiRet(tcpsrv.SetCBOnErrClose(pOurTcpsrv, onErrClose));
		CHKiRet(tcpsrv.SetDrvrMode(pOurTcpsrv, iStrmDrvrMode));
		CHKiRet(tcpsrv.SetAddtlFrameDelim(pOurTcpsrv, iAddtlFrameDelim));
		/* now set optional params, but only if they were actually configured */
		if(pszStrmDrvrAuthMode != NULL) {
			CHKiRet(tcpsrv.SetDrvrAuthMode(pOurTcpsrv, pszStrmDrvrAuthMode));
		}
		if(pPermPeersRoot != NULL) {
			CHKiRet(tcpsrv.SetDrvrPermPeers(pOurTcpsrv, pPermPeersRoot));
		}
	}

	/* initialized, now add socket */
	CHKiRet(tcpsrv.SetInputName(pOurTcpsrv, pszInputName == NULL ?
						UCHAR_CONSTANT("imtcp") : pszInputName));
	tcpsrv.configureTCPListen(pOurTcpsrv, pNewVal);

finalize_it:
	if(iRet != RS_RET_OK) {
		errmsg.LogError(0, NO_ERRCODE, "error %d trying to add listener", iRet);
		if(pOurTcpsrv != NULL)
			tcpsrv.Destruct(&pOurTcpsrv);
	}
	RETiRet;
}

/* This function is called to gather input.
 */
BEGINrunInput
CODESTARTrunInput
	/* TODO: we must be careful to start the listener here. Currently, tcpsrv.c seems to
	 * do that in ConstructFinalize
	 */
	CHKiRet(tcpsrv.ConstructFinalize(pOurTcpsrv));
	iRet = tcpsrv.Run(pOurTcpsrv);
finalize_it:
ENDrunInput


/* initialize and return if will run or not */
BEGINwillRun
CODESTARTwillRun
	/* first apply some config settings */
	net.PrintAllowedSenders(2); /* TCP */
	if(pOurTcpsrv == NULL)
		ABORT_FINALIZE(RS_RET_NO_RUN);
finalize_it:
ENDwillRun


BEGINafterRun
CODESTARTafterRun
	/* do cleanup here */
	net.clearAllowedSenders(UCHAR_CONSTANT("TCP"));
ENDafterRun


BEGINmodExit
CODESTARTmodExit
	if(pOurTcpsrv != NULL)
		iRet = tcpsrv.Destruct(&pOurTcpsrv);

	if(pPermPeersRoot != NULL) {
		net.DestructPermittedPeers(&pPermPeersRoot);
	}

	/* release objects we used */
	objRelease(net, LM_NET_FILENAME);
	objRelease(netstrm, LM_NETSTRMS_FILENAME);
	objRelease(tcps_sess, LM_TCPSRV_FILENAME);
	objRelease(tcpsrv, LM_TCPSRV_FILENAME);
	objRelease(errmsg, CORE_COMPONENT);
ENDmodExit


static rsRetVal
resetConfigVariables(uchar __attribute__((unused)) *pp, void __attribute__((unused)) *pVal)
{
	iTCPSessMax = 200;
	iStrmDrvrMode = 0;
	iAddtlFrameDelim = TCPSRV_NO_ADDTL_DELIMITER;
	if(pszInputName != NULL) {
		free(pszInputName);
		pszInputName = NULL;
	}
	if(pszStrmDrvrAuthMode != NULL) {
		free(pszStrmDrvrAuthMode);
		pszStrmDrvrAuthMode = NULL;
	}
	return RS_RET_OK;
}



BEGINqueryEtryPt
CODESTARTqueryEtryPt
CODEqueryEtryPt_STD_IMOD_QUERIES
ENDqueryEtryPt


BEGINmodInit()
CODESTARTmodInit
	*ipIFVersProvided = CURR_MOD_IF_VERSION; /* we only support the current interface specification */
CODEmodInit_QueryRegCFSLineHdlr
	pOurTcpsrv = NULL;
	/* request objects we use */
	CHKiRet(objUse(net, LM_NET_FILENAME));
	CHKiRet(objUse(netstrm, LM_NETSTRMS_FILENAME));
	CHKiRet(objUse(tcps_sess, LM_TCPSRV_FILENAME));
	CHKiRet(objUse(tcpsrv, LM_TCPSRV_FILENAME));
	CHKiRet(objUse(errmsg, CORE_COMPONENT));

	/* register config file handlers */
	CHKiRet(omsdRegCFSLineHdlr(UCHAR_CONSTANT("inputtcpserverrun"), 0, eCmdHdlrGetWord,
				   addTCPListener, NULL, STD_LOADABLE_MODULE_ID));
	CHKiRet(omsdRegCFSLineHdlr(UCHAR_CONSTANT("inputtcpmaxsessions"), 0, eCmdHdlrInt,
				   NULL, &iTCPSessMax, STD_LOADABLE_MODULE_ID));
	CHKiRet(omsdRegCFSLineHdlr(UCHAR_CONSTANT("inputtcpserverstreamdrivermode"), 0,
				   eCmdHdlrInt, NULL, &iStrmDrvrMode, STD_LOADABLE_MODULE_ID));
	CHKiRet(omsdRegCFSLineHdlr(UCHAR_CONSTANT("inputtcpserverstreamdriverauthmode"), 0,
				   eCmdHdlrGetWord, NULL, &pszStrmDrvrAuthMode, STD_LOADABLE_MODULE_ID));
	CHKiRet(omsdRegCFSLineHdlr(UCHAR_CONSTANT("inputtcpserverstreamdriverpermittedpeer"), 0,
				   eCmdHdlrGetWord, setPermittedPeer, NULL, STD_LOADABLE_MODULE_ID));
	CHKiRet(omsdRegCFSLineHdlr(UCHAR_CONSTANT("inputtcpserveraddtlframedelimiter"), 0, eCmdHdlrInt,
				   NULL, &iAddtlFrameDelim, STD_LOADABLE_MODULE_ID));
	CHKiRet(omsdRegCFSLineHdlr(UCHAR_CONSTANT("inputtcpserverinputname"), 0,
				   eCmdHdlrGetWord, NULL, &pszInputName, STD_LOADABLE_MODULE_ID));
	CHKiRet(omsdRegCFSLineHdlr(UCHAR_CONSTANT("resetconfigvariables"), 1, eCmdHdlrCustomHandler,
		resetConfigVariables, NULL, STD_LOADABLE_MODULE_ID));
ENDmodInit


/* vim:set ai:
 */