diff options
Diffstat (limited to 'tcpclt.c')
| -rw-r--r-- | tcpclt.c | 461 |
1 files changed, 461 insertions, 0 deletions
diff --git a/tcpclt.c b/tcpclt.c new file mode 100644 index 00000000..7262737c --- /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: + */ |