moved TCPSend() and frame building code to tcpsyslog.c

1 files changed, 225 insertions, 1 deletions

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<sp>" 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:
  */