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-rw-r--r--omfwd.c370
1 files changed, 370 insertions, 0 deletions
diff --git a/omfwd.c b/omfwd.c
index 44e1861e..81aa5424 100644
--- a/omfwd.c
+++ b/omfwd.c
@@ -41,6 +41,7 @@
#include <assert.h>
#include <errno.h>
#include <ctype.h>
+#include <unistd.h>
#ifdef USE_PTHREADS
#include <pthread.h>
#endif
@@ -113,6 +114,375 @@ CODESTARTdbgPrintInstInfo
printf("%s", f->f_un.f_forw.f_hname);
ENDdbgPrintInstInfo
+/* CODE FOR SENDING TCP MESSAGES */
+
+/* get send status
+ * rgerhards, 2005-10-24
+ */
+static void TCPSendSetStatus(selector_t *f, enum TCPSendStatus iNewState)
+{
+ assert(f != NULL);
+ assert(f->f_type == F_FORW);
+ assert(f->f_un.f_forw.protocol == FORW_TCP);
+ assert( (iNewState == TCP_SEND_NOTCONNECTED)
+ || (iNewState == TCP_SEND_CONNECTING)
+ || (iNewState == TCP_SEND_READY));
+
+ /* there can potentially be a race condition, so guard by mutex */
+# ifdef USE_PTHREADS
+ pthread_mutex_lock(&f->f_un.f_forw.mtxTCPSend);
+# endif
+ f->f_un.f_forw.status = iNewState;
+# ifdef USE_PTHREADS
+ pthread_mutex_unlock(&f->f_un.f_forw.mtxTCPSend);
+# endif
+}
+
+
+/* set send status
+ * rgerhards, 2005-10-24
+ */
+static enum TCPSendStatus TCPSendGetStatus(selector_t *f)
+{
+ enum TCPSendStatus eState;
+ assert(f != NULL);
+ assert(f->f_type == F_FORW);
+ assert(f->f_un.f_forw.protocol == FORW_TCP);
+
+ /* there can potentially be a race condition, so guard by mutex */
+# ifdef USE_PTHREADS
+ pthread_mutex_lock(&f->f_un.f_forw.mtxTCPSend);
+# endif
+ eState = f->f_un.f_forw.status;
+# ifdef USE_PTHREADS
+ pthread_mutex_unlock(&f->f_un.f_forw.mtxTCPSend);
+# endif
+
+ return eState;
+}
+
+
+/* Initialize TCP sockets (for sender)
+ * This is done once per selector line, if not yet initialized.
+ */
+static int TCPSendCreateSocket(selector_t *f, struct addrinfo *addrDest)
+{
+ int fd;
+ struct addrinfo *r;
+
+ assert(f != NULL);
+
+ 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
+ */
+# ifndef USE_PTHREADS
+ /* set to nonblocking - rgerhards 2005-07-20 */
+ fcntl(fd, F_SETFL, fcntl(fd, F_GETFL) | O_NONBLOCK);
+# endif
+ if (connect (fd, r->ai_addr, r->ai_addrlen) != 0) {
+ if(errno == EINPROGRESS) {
+ /* this is normal - will complete during select */
+ TCPSendSetStatus(f, TCP_SEND_CONNECTING);
+ return fd;
+ } else {
+ dprintf("create tcp connection failed, reason %s",
+ strerror(errno));
+ }
+
+ }
+ else {
+ TCPSendSetStatus(f, TCP_SEND_READY);
+ return fd;
+ }
+ close(fd);
+ }
+ else {
+ dprintf("couldn't create send socket, reason %s", strerror(errno));
+ }
+ r = r->ai_next;
+ }
+
+ dprintf("no working socket could be obtained");
+
+ return -1;
+}
+
+/* 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 safes 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
+ *
+ * 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 int TCPSend(selector_t *f, char *msg, size_t len)
+{
+ int retry = 0;
+ int done = 0;
+ int bIsCompressed;
+ int lenSend;
+ char *buf = NULL; /* if this is non-NULL, it MUST be freed before return! */
+ enum TCPSendStatus eState;
+ TCPFRAMINGMODE framingToUse;
+
+ assert(f != NULL);
+ assert(msg != NULL);
+ assert(len > 0);
+
+ 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 : f->f_un.f_forw.tcp_framing;
+
+ do { /* try to send message */
+ if(f->f_file <= 0) {
+ /* we need to open the socket first */
+ if((f->f_file = TCPSendCreateSocket(f, f->f_un.f_forw.f_addr)) <= 0) {
+ return -1;
+ }
+ }
+
+ eState = TCPSendGetStatus(f); /* cache info */
+
+ if(eState == TCP_SEND_CONNECTING) {
+ /* In this case, we save the buffer. If we have a
+ * system with few messages, that hopefully prevents
+ * message loss at all. However, we make no further attempts,
+ * just the first message is saved. So we only try this
+ * if there is not yet a saved message present.
+ * rgerhards 2005-07-20
+ */
+ if(f->f_un.f_forw.savedMsg == NULL) {
+ f->f_un.f_forw.savedMsg = malloc(len * sizeof(char));
+ if(f->f_un.f_forw.savedMsg == NULL)
+ return 0; /* nothing we can do... */
+ memcpy(f->f_un.f_forw.savedMsg, msg, len);
+ f->f_un.f_forw.savedMsgLen = len;
+ }
+ return 0;
+ } else if(eState != TCP_SEND_READY)
+ /* This here is debatable. For the time being, we
+ * accept the loss of a single message (e.g. during
+ * connection setup in favour of not messing with
+ * wait time and timeouts. The reason is that such
+ * things might otherwise cost us considerable message
+ * loss on the receiving side (even at a timeout set
+ * to just 1 second). - rgerhards 2005-07-20
+ */
+ return 0;
+
+ /* 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')) {
+ if(buf != NULL)
+ free(buf);
+ /* 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
+ */
+ dprintf("Error: out of memory when building TCP octet-counted "
+ "frame. Message is lost, trying to continue.\n");
+ return 0;
+ }
+
+ 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 */
+
+ lenSend = send(f->f_file, msg, len, 0);
+ dprintf("TCP sent %d bytes, requested %d, msg: '%s'\n", lenSend, len,
+ bIsCompressed ? "***compressed***" : msg);
+ if((unsigned)lenSend == len) {
+ /* all well */
+ if(buf != NULL) {
+ free(buf);
+ }
+ return 0;
+ } else if(lenSend != -1) {
+ /* no real error, could "just" not send everything...
+ * For the time being, we ignore this...
+ * rgerhards, 2005-10-25
+ */
+ dprintf("message not completely (tcp)send, ignoring %d\n", lenSend);
+# if USE_PTHREADS
+ usleep(1000); /* experimental - might be benefitial in this situation */
+# endif
+ if(buf != NULL)
+ free(buf);
+ return 0;
+ }
+
+ switch(errno) {
+ case EMSGSIZE:
+ dprintf("message not (tcp)send, too large\n");
+ /* This is not a real error, so it is not flagged as one */
+ if(buf != NULL)
+ free(buf);
+ return 0;
+ break;
+ case EINPROGRESS:
+ case EAGAIN:
+ dprintf("message not (tcp)send, would block\n");
+# if USE_PTHREADS
+ usleep(1000); /* experimental - might be benefitial in this situation */
+# endif
+ /* we loose this message, but that's better than loosing
+ * all ;)
+ */
+ /* This is not a real error, so it is not flagged as one */
+ if(buf != NULL)
+ free(buf);
+ return 0;
+ break;
+ default:
+ dprintf("message not (tcp)send");
+ break;
+ }
+
+ if(retry == 0) {
+ ++retry;
+ /* try to recover */
+ close(f->f_file);
+ TCPSendSetStatus(f, TCP_SEND_NOTCONNECTED);
+ f->f_file = -1;
+ } else {
+ if(buf != NULL)
+ free(buf);
+ return -1;
+ }
+ } while(!done); /* warning: do ... while() */
+ /*NOT REACHED*/
+
+ if(buf != NULL)
+ free(buf);
+ return -1; /* only to avoid compiler warning! */
+}
+
+
/* get the syslog forward port from selector_t. The passed in
* struct must be one that is setup for forwarding.
* rgerhards, 2007-06-28
generated by cgit (git 2.34.1) at 2024-11-20 07:16:20 +0000