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/* tcps_sess.c
*
* This implements a session of the tcpsrv object. For general
* comments, see header of tcpsrv.c.
*
* NOTE: read comments in module-template.h to understand how this file
* works!
*
* File begun on 2008-03-01 by RGerhards (extracted from tcpsrv.c)
*
* Copyright 2007, 2008 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.
*/
#include "config.h"
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <errno.h>
#include <ctype.h>

#include "rsyslog.h"
#include "dirty.h"
#include "unicode-helper.h"
#include "module-template.h"
#include "net.h"
#include "tcpsrv.h"
#include "tcps_sess.h"
#include "obj.h"
#include "errmsg.h"
#include "netstrm.h"
#include "msg.h"
#include "datetime.h"
#include "prop.h"
#include "debug.h"


/* static data */
DEFobjStaticHelpers
DEFobjCurrIf(glbl)
DEFobjCurrIf(errmsg)
DEFobjCurrIf(netstrm)
DEFobjCurrIf(prop)
DEFobjCurrIf(datetime)

static int iMaxLine; /* maximum size of a single message */


/* forward definitions */
static rsRetVal Close(tcps_sess_t *pThis);


/* Standard-Constructor */
BEGINobjConstruct(tcps_sess) /* be sure to specify the object type also in END macro! */
pThis->iMsg = 0; /* just make sure... */
pThis->bAtStrtOfFram = 1; /* indicate frame header expected */
pThis->eFraming = TCP_FRAMING_OCTET_STUFFING; /* just make sure... */
/* now allocate the message reception buffer */
CHKmalloc(pThis->pMsg = (uchar*) MALLOC(sizeof(uchar) * iMaxLine + 1));
finalize_it:
ENDobjConstruct(tcps_sess)


/* ConstructionFinalizer
*/
static rsRetVal
tcps_sessConstructFinalize(tcps_sess_t __attribute__((unused)) *pThis)
{
DEFiRet;
ISOBJ_TYPE_assert(pThis, tcps_sess);
if(pThis->pSrv->OnSessConstructFinalize != NULL) {
CHKiRet(pThis->pSrv->OnSessConstructFinalize(&pThis->pUsr));
}

finalize_it:
RETiRet;
}


/* destructor for the tcps_sess object */
BEGINobjDestruct(tcps_sess) /* be sure to specify the object type also in END and CODESTART macros! */
CODESTARTobjDestruct(tcps_sess)
if(pThis->pStrm != NULL)
netstrm.Destruct(&pThis->pStrm);

if(pThis->pSrv->pOnSessDestruct != NULL) {
pThis->pSrv->pOnSessDestruct(&pThis->pUsr);
}
/* now destruct our own properties */
if(pThis->fromHost != NULL)
CHKiRet(prop.Destruct(&pThis->fromHost));
if(pThis->fromHostIP != NULL)
CHKiRet(prop.Destruct(&pThis->fromHostIP));
free(pThis->pMsg);
ENDobjDestruct(tcps_sess)


/* debugprint for the tcps_sess object */
BEGINobjDebugPrint(tcps_sess) /* be sure to specify the object type also in END and CODESTART macros! */
CODESTARTobjDebugPrint(tcps_sess)
ENDobjDebugPrint(tcps_sess)


/* set property functions */
/* set the hostname. Note that the caller *hands over* the string. That is,
* the caller no longer controls it once SetHost() has received it. Most importantly,
* the caller must not free it. -- rgerhards, 2008-04-24
*/
static rsRetVal
SetHost(tcps_sess_t *pThis, uchar *pszHost)
{
DEFiRet;

ISOBJ_TYPE_assert(pThis, tcps_sess);

if(pThis->fromHost == NULL)
CHKiRet(prop.Construct(&pThis->fromHost));

CHKiRet(prop.SetString(pThis->fromHost, pszHost, ustrlen(pszHost)));

finalize_it:
free(pszHost); /* we must free according to our (old) calling conventions */
RETiRet;
}

/* set the remote host's IP. Note that the caller *hands over* the string. That is,
* the caller no longer controls it once SetHostIP() has received it. Most importantly,
* the caller must not free it. -- rgerhards, 2008-05-16
*/
static rsRetVal
SetHostIP(tcps_sess_t *pThis, uchar *pszHostIP)
{
DEFiRet;

ISOBJ_TYPE_assert(pThis, tcps_sess);

if(pThis->fromHostIP == NULL)
CHKiRet(prop.Construct(&pThis->fromHostIP));

CHKiRet(prop.SetString(pThis->fromHostIP, pszHostIP, ustrlen(pszHostIP)));

finalize_it:
free(pszHostIP);
RETiRet;
}

static rsRetVal
SetStrm(tcps_sess_t *pThis, netstrm_t *pStrm)
{
DEFiRet;
ISOBJ_TYPE_assert(pThis, tcps_sess);
pThis->pStrm = pStrm;
RETiRet;
}


static rsRetVal
SetMsgIdx(tcps_sess_t *pThis, int idx)
{
DEFiRet;
ISOBJ_TYPE_assert(pThis, tcps_sess);
pThis->iMsg = idx;
RETiRet;
}


/* set our parent, the tcpsrv object */
static rsRetVal
SetTcpsrv(tcps_sess_t *pThis, tcpsrv_t *pSrv)
{
DEFiRet;
ISOBJ_TYPE_assert(pThis, tcps_sess);
ISOBJ_TYPE_assert(pSrv, tcpsrv);
pThis->pSrv = pSrv;
RETiRet;
}


/* set our parent listener info*/
static rsRetVal
SetLstnInfo(tcps_sess_t *pThis, tcpLstnPortList_t *pLstnInfo)
{
DEFiRet;
ISOBJ_TYPE_assert(pThis, tcps_sess);
assert(pLstnInfo != NULL);
pThis->pLstnInfo = pLstnInfo;
RETiRet;
}


static rsRetVal
SetUsrP(tcps_sess_t *pThis, void *pUsr)
{
DEFiRet;
pThis->pUsr = pUsr;
RETiRet;
}


static rsRetVal
SetOnMsgReceive(tcps_sess_t *pThis, rsRetVal (*OnMsgReceive)(tcps_sess_t*, uchar*, int))
{
DEFiRet;
pThis->DoSubmitMessage = OnMsgReceive;
RETiRet;
}


/* This is a helper for submitting the message to the rsyslog core.
* It does some common processing, including resetting the various
* state variables to a "processed" state.
* Note that this function is also called if we had a buffer overflow
* due to a too-long message. So far, there is no indication this
* happened and it may be worth thinking about different handling
* of this case (what obviously would require a change to this
* function or some related code).
* rgerhards, 2009-04-23
*/
static rsRetVal
defaultDoSubmitMessage(tcps_sess_t *pThis, struct syslogTime *stTime, time_t ttGenTime, multi_submit_t *pMultiSub)
{
msg_t *pMsg;
DEFiRet;

ISOBJ_TYPE_assert(pThis, tcps_sess);

if(pThis->iMsg == 0) {
DBGPRINTF("discarding zero-sized message\n");
FINALIZE;
}

if(pThis->DoSubmitMessage != NULL) {
pThis->DoSubmitMessage(pThis, pThis->pMsg, pThis->iMsg);
FINALIZE;
}

/* we now create our own message object and submit it to the queue */
CHKiRet(msgConstructWithTime(&pMsg, stTime, ttGenTime));
MsgSetRawMsg(pMsg, (char*)pThis->pMsg, pThis->iMsg);
MsgSetInputName(pMsg, pThis->pLstnInfo->pInputName);
MsgSetFlowControlType(pMsg, eFLOWCTL_LIGHT_DELAY);
pMsg->msgFlags = NEEDS_PARSING | PARSE_HOSTNAME;
MsgSetRcvFrom(pMsg, pThis->fromHost);
CHKiRet(MsgSetRcvFromIP(pMsg, pThis->fromHostIP));
MsgSetRuleset(pMsg, pThis->pLstnInfo->pRuleset);

if(pMultiSub == NULL) {
CHKiRet(submitMsg(pMsg));
} else {
pMultiSub->ppMsgs[pMultiSub->nElem++] = pMsg;
if(pMultiSub->nElem == pMultiSub->maxElem)
CHKiRet(multiSubmitMsg(pMultiSub));
}


finalize_it:
/* reset status variables */
pThis->bAtStrtOfFram = 1;
pThis->iMsg = 0;

RETiRet;
}



/* This should be called before a normal (non forced) close
* of a TCP session. This function checks if there is any unprocessed
* message left in the TCP stream. Such a message is probably a
* fragement. If evrything goes well, we must be right at the
* beginnig of a new frame without any data received from it. If
* not, there is some kind of a framing error. I think I remember that
* some legacy syslog/TCP implementations have non-LF terminated
* messages at the end of the stream. For now, we allow this behaviour.
* Later, it should probably become a configuration option.
* rgerhards, 2006-12-07
*/
static rsRetVal
PrepareClose(tcps_sess_t *pThis)
{
struct syslogTime stTime;
time_t ttGenTime;
DEFiRet;

ISOBJ_TYPE_assert(pThis, tcps_sess);

if(pThis->bAtStrtOfFram == 1) {
/* this is how it should be. There is no unprocessed
* data left and such we have nothing to do. For simplicity
* reasons, we immediately return in that case.
*/
FINALIZE;
}

/* we have some data left! */
if(pThis->eFraming == TCP_FRAMING_OCTET_COUNTING) {
/* In this case, we have an invalid frame count and thus
* generate an error message and discard the frame.
*/
errmsg.LogError(0, NO_ERRCODE, "Incomplete frame at end of stream in session %p - "
"ignoring extra data (a message may be lost).\n", pThis->pStrm);
/* nothing more to do */
} else { /* here, we have traditional framing. Missing LF at the end
* of message may occur. As such, we process the message in
* this case.
*/
dbgprintf("Extra data at end of stream in legacy syslog/tcp message - processing\n");
datetime.getCurrTime(&stTime, &ttGenTime);
defaultDoSubmitMessage(pThis, &stTime, ttGenTime, NULL);
}

finalize_it:
RETiRet;
}


/* Closes a TCP session
* No attention is paid to the return code
* of close, so potential-double closes are not detected.
*/
static rsRetVal
Close(tcps_sess_t *pThis)
{
DEFiRet;

ISOBJ_TYPE_assert(pThis, tcps_sess);
netstrm.Destruct(&pThis->pStrm);
if(pThis->fromHost != NULL) {
prop.Destruct(&pThis->fromHost);
}
if(pThis->fromHostIP != NULL)
prop.Destruct(&pThis->fromHostIP);

RETiRet;
}


/* process the data received. As TCP is stream based, we need to process the
* data inside a state machine. The actual data received is passed in byte-by-byte
* from DataRcvd, and this function here compiles messages from them and submits
* the end result to the queue. Introducing this function fixes a long-term bug ;)
* rgerhards, 2008-03-14
*/
static rsRetVal
processDataRcvd(tcps_sess_t *pThis, char c, struct syslogTime *stTime, time_t ttGenTime, multi_submit_t *pMultiSub)
{
DEFiRet;
ISOBJ_TYPE_assert(pThis, tcps_sess);

if(pThis->inputState == eAtStrtFram) {
if(isdigit((int) c)) {
pThis->inputState = eInOctetCnt;
pThis->iOctetsRemain = 0;
pThis->eFraming = TCP_FRAMING_OCTET_COUNTING;
} else {
pThis->inputState = eInMsg;
pThis->eFraming = TCP_FRAMING_OCTET_STUFFING;
}
}

if(pThis->inputState == eInOctetCnt) {
if(isdigit(c)) {
pThis->iOctetsRemain = pThis->iOctetsRemain * 10 + c - '0';
} else { /* done with the octet count, so this must be the SP terminator */
dbgprintf("TCP Message with octet-counter, size %d.\n", pThis->iOctetsRemain);
if(c != ' ') {
errmsg.LogError(0, NO_ERRCODE, "Framing Error in received TCP message: "
"delimiter is not SP but has ASCII value %d.\n", c);
}
if(pThis->iOctetsRemain < 1) {
/* TODO: handle the case where the octet count is 0! */
dbgprintf("Framing Error: invalid octet count\n");
errmsg.LogError(0, NO_ERRCODE, "Framing Error in received TCP message: "
"invalid octet count %d.\n", pThis->iOctetsRemain);
} else if(pThis->iOctetsRemain > iMaxLine) {
/* while we can not do anything against it, we can at least log an indication
* that something went wrong) -- rgerhards, 2008-03-14
*/
dbgprintf("truncating message with %d octets - max msg size is %d\n",
pThis->iOctetsRemain, iMaxLine);
errmsg.LogError(0, NO_ERRCODE, "received oversize message: size is %d bytes, "
"max msg size is %d, truncating...\n", pThis->iOctetsRemain, iMaxLine);
}
pThis->inputState = eInMsg;
}
} else {
assert(pThis->inputState == eInMsg);
if(pThis->iMsg >= iMaxLine) {
/* emergency, we now need to flush, no matter if we are at end of message or not... */
dbgprintf("error: message received is larger than max msg size, we split it\n");
defaultDoSubmitMessage(pThis, stTime, ttGenTime, pMultiSub);
/* we might think if it is better to ignore the rest of the
* message than to treat it as a new one. Maybe this is a good
* candidate for a configuration parameter...
* rgerhards, 2006-12-04
*/
}

if(( ((c == '\n') && !pThis->pSrv->bDisableLFDelim)
|| ((pThis->pSrv->addtlFrameDelim != TCPSRV_NO_ADDTL_DELIMITER) && (c == pThis->pSrv->addtlFrameDelim))
) && pThis->eFraming == TCP_FRAMING_OCTET_STUFFING) { /* record delimiter? */
defaultDoSubmitMessage(pThis, stTime, ttGenTime, pMultiSub);
pThis->inputState = eAtStrtFram;
} else {
/* IMPORTANT: here we copy the actual frame content to the message - for BOTH framing modes!
* If we have a message that is larger than the max msg size, we truncate it. This is the best
* we can do in light of what the engine supports. -- rgerhards, 2008-03-14
*/
if(pThis->iMsg < iMaxLine) {
*(pThis->pMsg + pThis->iMsg++) = c;
}
}

if(pThis->eFraming == TCP_FRAMING_OCTET_COUNTING) {
/* do we need to find end-of-frame via octet counting? */
pThis->iOctetsRemain--;
if(pThis->iOctetsRemain < 1) {
/* we have end of frame! */
defaultDoSubmitMessage(pThis, stTime, ttGenTime, pMultiSub);
pThis->inputState = eAtStrtFram;
}
}
}

RETiRet;
}


/* Processes the data received via a TCP session. If there
* is no other way to handle it, data is discarded.
* Input parameter data is the data received, iLen is its
* len as returned from recv(). iLen must be 1 or more (that
* is errors must be handled by caller!). iTCPSess must be
* the index of the TCP session that received the data.
* rgerhards 2005-07-04
* And another change while generalizing. We now return either
* RS_RET_OK, which means the session should be kept open
* or anything else, which means it must be closed.
* rgerhards, 2008-03-01
* As a performance optimization, we pick up the timestamp here. Acutally,
* this *is* the *correct* reception step for all the data we received, because
* we have just received a bunch of data! -- rgerhards, 2009-06-16
*/
#define NUM_MULTISUB 1024
static rsRetVal
DataRcvd(tcps_sess_t *pThis, char *pData, size_t iLen)
{
multi_submit_t multiSub;
msg_t *pMsgs[NUM_MULTISUB];
struct syslogTime stTime;
time_t ttGenTime;
char *pEnd;
DEFiRet;

ISOBJ_TYPE_assert(pThis, tcps_sess);
assert(pData != NULL);
assert(iLen > 0);

datetime.getCurrTime(&stTime, &ttGenTime);
multiSub.ppMsgs = pMsgs;
multiSub.maxElem = NUM_MULTISUB;
multiSub.nElem = 0;

/* We now copy the message to the session buffer. */
pEnd = pData + iLen; /* this is one off, which is intensional */

while(pData < pEnd) {
CHKiRet(processDataRcvd(pThis, *pData++, &stTime, ttGenTime, &multiSub));
}

if(multiSub.nElem > 0) {
/* submit anything that was not yet submitted */
CHKiRet(multiSubmitMsg(&multiSub));
}

finalize_it:
RETiRet;
}
#undef NUM_MULTISUB


/* queryInterface function
* rgerhards, 2008-02-29
*/
BEGINobjQueryInterface(tcps_sess)
CODESTARTobjQueryInterface(tcps_sess)
if(pIf->ifVersion != tcps_sessCURR_IF_VERSION) { /* check for current version, increment on each change */
ABORT_FINALIZE(RS_RET_INTERFACE_NOT_SUPPORTED);
}

/* ok, we have the right interface, so let's fill it
* Please note that we may also do some backwards-compatibility
* work here (if we can support an older interface version - that,
* of course, also affects the "if" above).
*/
pIf->DebugPrint = tcps_sessDebugPrint;
pIf->Construct = tcps_sessConstruct;
pIf->ConstructFinalize = tcps_sessConstructFinalize;
pIf->Destruct = tcps_sessDestruct;

pIf->PrepareClose = PrepareClose;
pIf->Close = Close;
pIf->DataRcvd = DataRcvd;

pIf->SetUsrP = SetUsrP;
pIf->SetTcpsrv = SetTcpsrv;
pIf->SetLstnInfo = SetLstnInfo;
pIf->SetHost = SetHost;
pIf->SetHostIP = SetHostIP;
pIf->SetStrm = SetStrm;
pIf->SetMsgIdx = SetMsgIdx;
pIf->SetOnMsgReceive = SetOnMsgReceive;
finalize_it:
ENDobjQueryInterface(tcps_sess)


/* exit our class
* rgerhards, 2008-03-10
*/
BEGINObjClassExit(tcps_sess, OBJ_IS_LOADABLE_MODULE) /* CHANGE class also in END MACRO! */
CODESTARTObjClassExit(tcps_sess)
/* release objects we no longer need */
objRelease(errmsg, CORE_COMPONENT);
objRelease(netstrm, LM_NETSTRMS_FILENAME);
objRelease(datetime, CORE_COMPONENT);
objRelease(prop, CORE_COMPONENT);
ENDObjClassExit(tcps_sess)


/* Initialize our class. Must be called as the very first method
* before anything else is called inside this class.
* rgerhards, 2008-02-29
*/
BEGINObjClassInit(tcps_sess, 1, OBJ_IS_CORE_MODULE) /* class, version - CHANGE class also in END MACRO! */
/* request objects we use */
CHKiRet(objUse(errmsg, CORE_COMPONENT));
CHKiRet(objUse(netstrm, LM_NETSTRMS_FILENAME));
CHKiRet(objUse(datetime, CORE_COMPONENT));
CHKiRet(objUse(prop, CORE_COMPONENT));

CHKiRet(objUse(glbl, CORE_COMPONENT));
iMaxLine = glbl.GetMaxLine(); /* get maximum size we currently support */
objRelease(glbl, CORE_COMPONENT);

/* set our own handlers */
OBJSetMethodHandler(objMethod_DEBUGPRINT, tcps_sessDebugPrint);
OBJSetMethodHandler(objMethod_CONSTRUCTION_FINALIZER, tcps_sessConstructFinalize);
ENDObjClassInit(tcps_sess)

/* vim:set ai:
*/
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