From 1990c08536f3880053508ab6b60aab8cee9760ec Mon Sep 17 00:00:00 2001 From: Rainer Gerhards Date: Fri, 28 Dec 2007 14:34:48 +0000 Subject: moved TCPSend() and frame building code to tcpsyslog.c --- tcpsyslog.c | 226 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 225 insertions(+), 1 deletion(-) (limited to 'tcpsyslog.c') diff --git a/tcpsyslog.c b/tcpsyslog.c index 85ff2566..27e1db2a 100644 --- a/tcpsyslog.c +++ b/tcpsyslog.c @@ -1009,12 +1009,236 @@ void TCPSessGSSDeinit(void) { #endif /* #ifdef USE_GSSAPI */ -#endif /******************************************************************** * ### END OF SYSLOG/TCP CODE ### ********************************************************************/ + +/* ----------------------------------------------------------------- * + * CODE THAT SHALL GO INTO ITS OWN MODULE (SENDING) * + * ----------------------------------------------------------------- */ + + + +/* Build frame based on selected framing + * This function was created by pulling code from TCPSend() + * on 2007-12-27 by rgerhards. Older comments are still relevant. + * + * In order to support compressed messages via TCP, we must support an + * octet-counting based framing (LF may be part of the compressed message). + * We are now supporting the same mode that is available in IETF I-D + * syslog-transport-tls-05 (current at the time of this writing). This also + * eases things when we go ahead and implement that framing. I have now made + * available two cases where this framing is used: either by explitely + * specifying it in the config file or implicitely when sending a compressed + * message. In the later case, compressed and uncompressed messages within + * the same session have different framings. If it is explicitely set to + * octet-counting, only this framing mode is used within the session. + * rgerhards, 2006-12-07 + */ +static rsRetVal TCPSendBldFrame(TCPFRAMINGMODE rqdFraming, char **pmsg, size_t *plen, int *pbMustBeFreed) +{ + DEFiRet; + TCPFRAMINGMODE framingToUse; + int bIsCompressed; + size_t len; + char *msg; + char *buf = NULL; /* if this is non-NULL, it MUST be freed before return! */ + + assert(plen != NULL); + assert(pbMustBeFreed != NULL); + assert(pmsg != NULL); + + msg = *pmsg; + len = *plen; + bIsCompressed = *msg == 'z'; /* cache this, so that we can modify the message buffer */ + /* select framing for this record. If we have a compressed record, we always need to + * use octet counting because the data potentially contains all control characters + * including LF. + */ + framingToUse = bIsCompressed ? TCP_FRAMING_OCTET_COUNTING : rqdFraming; + + /* now check if we need to add a line terminator. We need to + * copy the string in memory in this case, this is probably + * quicker than using writev and definitely quicker than doing + * two socket calls. + * rgerhards 2005-07-22 + * + * Some messages already contain a \n character at the end + * of the message. We append one only if we there is not + * already one. This seems the best fit, though this also + * means the message does not arrive unaltered at the final + * destination. But in the spirit of legacy syslog, this is + * probably the best to do... + * rgerhards 2005-07-20 + */ + + /* Build frame based on selected framing */ + if(framingToUse == TCP_FRAMING_OCTET_STUFFING) { + if((*(msg+len-1) != '\n')) { + /* in the malloc below, we need to add 2 to the length. The + * reason is that we a) add one character and b) len does + * not take care of the '\0' byte. Up until today, it was just + * +1 , which caused rsyslogd to sometimes dump core. + * I have added this comment so that the logic is not accidently + * changed again. rgerhards, 2005-10-25 + */ + if((buf = malloc((len + 2) * sizeof(char))) == NULL) { + /* extreme mem shortage, try to solve + * as good as we can. No point in calling + * any alarms, they might as well run out + * of memory (the risk is very high, so we + * do NOT risk that). If we have a message of + * more than 1 byte (what I guess), we simply + * overwrite the last character. + * rgerhards 2005-07-22 + */ + if(len > 1) { + *(msg+len-1) = '\n'; + } else { + /* we simply can not do anything in + * this case (its an error anyhow...). + */ + } + } else { + /* we got memory, so we can copy the message */ + memcpy(buf, msg, len); /* do not copy '\0' */ + *(buf+len) = '\n'; + *(buf+len+1) = '\0'; + msg = buf; /* use new one */ + ++len; /* care for the \n */ + } + } + } else { + /* Octect-Counting + * In this case, we need to always allocate a buffer. This is because + * we need to put a header in front of the message text + */ + char szLenBuf[16]; + int iLenBuf; + + /* important: the printf-mask is "%d" because there must be a + * space after the len! + *//* The chairs of the IETF syslog-sec WG have announced that it is + * consensus to do the octet count on the SYSLOG-MSG part only. I am + * now changing the code to reflect this. Hopefully, it will not change + * once again (there can no compatibility layer programmed for this). + * To be on the save side, I just comment the code out. I mark these + * comments with "IETF20061218". + * rgerhards, 2006-12-19 + */ + iLenBuf = snprintf(szLenBuf, sizeof(szLenBuf)/sizeof(char), "%d ", (int) len); + /* IETF20061218 iLenBuf = + snprintf(szLenBuf, sizeof(szLenBuf)/sizeof(char), "%d ", len + iLenBuf);*/ + + if((buf = malloc((len + iLenBuf) * sizeof(char))) == NULL) { + /* we are out of memory. This is an extreme situation. We do not + * call any alarm handlers because they most likely run out of mem, + * too. We are brave enough to call debug output, though. Other than + * that, there is nothing left to do. We can not sent the message (as + * in case of the other framing, because the message is incomplete. + * We could, however, send two chunks (header and text separate), but + * that would cause a lot of complexity in the code. So we think it + * is appropriate enough to just make sure we do not crash in this + * very unlikely case. For this, it is justified just to loose + * the message. Rgerhards, 2006-12-07 + */ + dbgprintf("Error: out of memory when building TCP octet-counted " + "frame. Message is lost, trying to continue.\n"); + ABORT_FINALIZE(RS_RET_OUT_OF_MEMORY); + } + + memcpy(buf, szLenBuf, iLenBuf); /* header */ + memcpy(buf + iLenBuf, msg, len); /* message */ + len += iLenBuf; /* new message size */ + msg = buf; /* set message buffer */ + } + + /* frame building complete, on to actual sending */ + + *plen = len; + if(buf == NULL) { + /* msg not modified */ + *pbMustBeFreed = 0; + } else { + *pmsg = msg; + *pbMustBeFreed = 1; + } + +finalize_it: + return iRet; +} + + +/* Sends a TCP message. It is first checked if the + * session is open and, if not, it is opened. Then the send + * is tried. If it fails, one silent re-try is made. If the send + * fails again, an error status (-1) is returned. If all goes well, + * 0 is returned. The TCP session is NOT torn down. + * For now, EAGAIN is ignored (causing message loss) - but it is + * hard to do something intelligent in this case. With this + * implementation here, we can not block and/or defer. Things are + * probably a bit better when we move to liblogging. The alternative + * would be to enhance the current select server with buffering and + * write descriptors. This seems not justified, given the expected + * short life span of this code (and the unlikeliness of this event). + * rgerhards 2005-07-06 + * This function is now expected to stay. Libloging won't be used for + * that purpose. I have added the param "len", because it is known by the + * caller and so saves us some time. Also, it MUST be given because there + * may be NULs inside msg so that we can not rely on strlen(). Please note + * that the restrictions outlined above do not existin in multi-threaded + * mode, which we assume will now be most often used. So there is no + * real issue with the potential message loss in single-threaded builds. + * rgerhards, 2006-11-30 + * I greatly restructured the function to be more generic and work + * with function pointers. So it now can be used with any type of transport, + * as long as it follows stream semantics. This was initially done to + * support plain TCP and GSS via common code. + */ +int TCPSend(void *pData, char *msg, size_t len, TCPFRAMINGMODE rqdFraming, + rsRetVal (*initFunc)(void*), + rsRetVal (*sendFunc)(void*, char*, size_t), + rsRetVal (*prepRetryFunc)(void*)) +{ + DEFiRet; + int bDone = 0; + int retry = 0; + int bMsgMustBeFreed = 0;/* must msg be freed at end of function? 0 - no, 1 - yes */ + + assert(pData != NULL); + assert(msg != NULL); + assert(len > 0); + + CHKiRet(TCPSendBldFrame(rqdFraming, &msg, &len, &bMsgMustBeFreed)); + + while(!bDone) { /* loop is broken when send succeeds or error occurs */ + CHKiRet(initFunc(pData)); + iRet = sendFunc(pData, msg, len); + + if(iRet == RS_RET_OK || retry > 0) { + /* we are done - either we succeeded or the retry failed */ + bDone = 1; + } else { /* OK, one retry */ + ++retry; + CHKiRet(prepRetryFunc(pData)); /* try to recover */ + } + } + +finalize_it: + if(bMsgMustBeFreed) + free(msg); + return iRet; +} + + +/* ----------------------------------------------------------------- * + * END OF CODE THAT SHALL GO INTO ITS OWN MODULE * + * ----------------------------------------------------------------- */ + +#endif + /* * vi:set ai: */ -- cgit