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authorRainer Gerhards <rgerhards@adiscon.com>2008-03-12 14:08:21 +0000
committerRainer Gerhards <rgerhards@adiscon.com>2008-03-12 14:08:21 +0000
commit618a7f6a220563a50909d0e15eb90ce222aced31 (patch)
tree484439581a66494bbed91aa6e53f4b571126e820 /tcpclt.c
parent9ddee5b38772f42f4371c6828a832f0d6267251d (diff)
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changed omgssapi and omfwd to utilize new object calling interface; made a
tcpclt class; (stage work, among others, for more intelligent recovery from TCP session recovery)
Diffstat (limited to 'tcpclt.c')
-rw-r--r--tcpclt.c461
1 files changed, 461 insertions, 0 deletions
diff --git a/tcpclt.c b/tcpclt.c
new file mode 100644
index 0000000..7262737
--- /dev/null
+++ b/tcpclt.c
@@ -0,0 +1,461 @@
+/* tcpclt.c
+ *
+ * This is the implementation of TCP-based syslog clients (the counterpart
+ * of the tcpsrv class).
+ *
+ * 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 "rsyslog.h"
+#include <stdio.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include <assert.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 "syslogd.h"
+#include "syslogd-types.h"
+#include "net.h"
+#include "tcpsyslog.h"
+#include "tcpclt.h"
+#include "module-template.h"
+#include "srUtils.h"
+
+MODULE_TYPE_LIB
+
+/* static data */
+DEFobjStaticHelpers
+
+/* Initialize TCP sockets (for sender)
+ * This is done once per selector line, if not yet initialized.
+ */
+static int
+CreateSocket(struct addrinfo *addrDest)
+{
+ int fd;
+ struct addrinfo *r;
+
+ r = addrDest;
+
+ while(r != NULL) {
+ fd = socket(r->ai_family, r->ai_socktype, r->ai_protocol);
+ if (fd != -1) {
+ /* We can not allow the TCP sender to block syslogd, at least
+ * not in a single-threaded design. That would cause rsyslogd to
+ * loose input messages - which obviously also would affect
+ * other selector lines, too. So we do set it to non-blocking and
+ * handle the situation ourselfs (by discarding messages). IF we run
+ * dual-threaded, however, the situation is different: in this case,
+ * the receivers and the selector line processing are only loosely
+ * coupled via a memory buffer. Now, I think, we can afford the extra
+ * wait time. Thus, we enable blocking mode for TCP if we compile with
+ * pthreads. -- rgerhards, 2005-10-25
+ * And now, we always run on multiple threads... -- rgerhards, 2007-12-20
+ */
+ if (connect (fd, r->ai_addr, r->ai_addrlen) != 0) {
+ if(errno == EINPROGRESS) {
+ /* this is normal - will complete later select */
+ return fd;
+ } else {
+ char errStr[1024];
+ dbgprintf("create tcp connection failed, reason %s",
+ rs_strerror_r(errno, errStr, sizeof(errStr)));
+ }
+
+ }
+ else {
+ return fd;
+ }
+ close(fd);
+ }
+ else {
+ char errStr[1024];
+ dbgprintf("couldn't create send socket, reason %s", rs_strerror_r(errno, errStr, sizeof(errStr)));
+ }
+ r = r->ai_next;
+ }
+
+ dbgprintf("no working socket could be obtained");
+
+ return -1;
+}
+
+
+
+/* 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(tcpclt_t *pThis, 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 : pThis->tcp_framing;
+
+ /* 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:
+ RETiRet;
+}
+
+
+/* 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.
+ */
+static int
+Send(tcpclt_t *pThis, void *pData, char *msg, size_t len)
+{
+ DEFiRet;
+ int bDone = 0;
+ int retry = 0;
+ int bMsgMustBeFreed = 0;/* must msg be freed at end of function? 0 - no, 1 - yes */
+
+ ISOBJ_TYPE_assert(pThis, tcpclt);
+ assert(pData != NULL);
+ assert(msg != NULL);
+ assert(len > 0);
+
+ CHKiRet(TCPSendBldFrame(pThis, &msg, &len, &bMsgMustBeFreed));
+
+ while(!bDone) { /* loop is broken when send succeeds or error occurs */
+ CHKiRet(pThis->initFunc(pData));
+ iRet = pThis->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(pThis->prepRetryFunc(pData)); /* try to recover */
+ }
+ }
+
+finalize_it:
+ if(bMsgMustBeFreed)
+ free(msg);
+ RETiRet;
+}
+
+
+/* set functions */
+static rsRetVal
+SetSendInit(tcpclt_t *pThis, rsRetVal (*pCB)(void*))
+{
+ DEFiRet;
+ pThis->initFunc = pCB;
+ RETiRet;
+}
+static rsRetVal
+SetSendPrepRetry(tcpclt_t *pThis, rsRetVal (*pCB)(void*))
+{
+ DEFiRet;
+ pThis->prepRetryFunc = pCB;
+ RETiRet;
+}
+static rsRetVal
+SetSendFrame(tcpclt_t *pThis, rsRetVal (*pCB)(void*, char*, size_t))
+{
+ DEFiRet;
+ pThis->sendFunc = pCB;
+ RETiRet;
+}
+static rsRetVal
+SetFraming(tcpclt_t *pThis, TCPFRAMINGMODE framing)
+{
+ DEFiRet;
+ pThis->tcp_framing = framing;
+ RETiRet;
+}
+
+
+/* Standard-Constructor
+ */
+BEGINobjConstruct(tcpclt) /* be sure to specify the object type also in END macro! */
+ENDobjConstruct(tcpclt)
+
+
+/* ConstructionFinalizer
+ */
+static rsRetVal
+tcpcltConstructFinalize(tcpclt_t __attribute__((unused)) *pThis)
+{
+ DEFiRet;
+ ISOBJ_TYPE_assert(pThis, tcpclt);
+
+ RETiRet;
+}
+
+
+/* destructor for the tcpclt object */
+BEGINobjDestruct(tcpclt) /* be sure to specify the object type also in END and CODESTART macros! */
+CODESTARTobjDestruct(tcpclt)
+
+ENDobjDestruct(tcpclt)
+
+
+/* ------------------------------ handling the interface plumbing ------------------------------ */
+
+/* queryInterface function
+ * rgerhards, 2008-03-12
+ */
+BEGINobjQueryInterface(tcpclt)
+CODESTARTobjQueryInterface(tcpclt)
+ if(pIf->ifVersion != tcpcltCURR_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->Construct = tcpcltConstruct;
+ pIf->ConstructFinalize = tcpcltConstructFinalize;
+ pIf->Destruct = tcpcltDestruct;
+
+ pIf->CreateSocket = CreateSocket;
+ pIf->Send = Send;
+
+ /* set functions */
+ pIf->SetSendInit = SetSendInit;
+ pIf->SetSendFrame = SetSendFrame;
+ pIf->SetSendPrepRetry = SetSendPrepRetry;
+ pIf->SetFraming = SetFraming;
+
+finalize_it:
+ENDobjQueryInterface(tcpclt)
+
+
+/* exit our class
+ * rgerhards, 2008-03-10
+ */
+BEGINObjClassExit(tcpclt, OBJ_IS_LOADABLE_MODULE) /* CHANGE class also in END MACRO! */
+CODESTARTObjClassExit(tcpclt)
+ /* release objects we no longer need */
+//objRelease(net, LM_NET_FILENAME);
+ENDObjClassExit(tcpclt)
+
+
+/* Initialize our class. Must be called as the very first method
+ * before anything else is called inside this class.
+ * rgerhards, 2008-02-29
+ */
+BEGINObjClassInit(tcpclt, 1, OBJ_IS_LOADABLE_MODULE) /* class, version - CHANGE class also in END MACRO! */
+ /* request objects we use */
+//CHKiRet(objUse(net, LM_NET_FILENAME));
+
+ /* set our own handlers */
+ OBJSetMethodHandler(objMethod_CONSTRUCTION_FINALIZER, tcpcltConstructFinalize);
+ENDObjClassInit(tcpclt)
+
+
+/* --------------- here now comes the plumbing that makes as a library module --------------- */
+
+
+BEGINmodExit
+CODESTARTmodExit
+ /* de-init in reverse order! */
+ tcpcltClassExit();
+ENDmodExit
+
+
+BEGINqueryEtryPt
+CODESTARTqueryEtryPt
+CODEqueryEtryPt_STD_LIB_QUERIES
+ENDqueryEtryPt
+
+
+BEGINmodInit()
+CODESTARTmodInit
+ *ipIFVersProvided = CURR_MOD_IF_VERSION; /* we only support the current interface specification */
+
+ /* Initialize all classes that are in our module - this includes ourselfs */
+ CHKiRet(tcpcltClassInit(pModInfo)); /* must be done after tcps_sess, as we use it */
+ENDmodInit
+
+
+/*
+ * vi:set ai:
+ */