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/* omfwd.c
* This is the implementation of the build-in forwarding output module.
*
* File begun on 2007-07-20 by RGerhards (extracted from syslogd.c)
* This file is under development and has not yet arrived at being fully
* self-contained and a real object. So far, it is mostly an excerpt
* of the "old" message code without any modifications. However, it
* helps to have things at the right place one we go to the meat of it.
*
* Copyright 2007 Rainer Gerhards and Adiscon GmbH.
*
* This program 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 2
* of the License, or (at your option) any later version.
*
* This program 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 this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* A copy of the GPL can be found in the file "COPYING" in this distribution.
*/
#include "config.h"
#ifdef SYSLOG_INET
#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <netinet/in.h>
#include <netdb.h>
#include <fnmatch.h>
#include <assert.h>
#include <errno.h>
#include "rsyslog.h"
#include "syslogd.h"
#include "syslogd-types.h"
#include "srUtils.h"
#include "net.h"
#include "omfwd.h"
#include "template.h"
#include "msg.h"
#include "tcpsyslog.h"
/*
* This table contains plain text for h_errno errors used by the
* net subsystem.
*/
static const char *sys_h_errlist[] = {
"No problem", /* NETDB_SUCCESS */
"Authoritative answer: host not found", /* HOST_NOT_FOUND */
"Non-authoritative answer: host not found, or serverfail", /* TRY_AGAIN */
"Non recoverable errors", /* NO_RECOVERY */
"Valid name, no data record of requested type", /* NO_DATA */
"no address, look for MX record" /* NO_ADDRESS */
};
/* call the shell action
* returns 0 if it succeeds, something else otherwise
*/
int doActionFwd(selector_t *f, time_t now)
{
char *psz; /* temporary buffering */
register unsigned l;
int i;
unsigned e, lsent = 0;
int bSendSuccess;
time_t fwd_suspend;
struct addrinfo *res, *r;
struct addrinfo hints;
assert(f != NULL);
switch (f->f_type) {
case F_FORW_SUSP:
fwd_suspend = time(NULL) - f->f_time;
if ( fwd_suspend >= INET_SUSPEND_TIME ) {
dprintf("\nForwarding suspension over, retrying FORW ");
f->f_type = F_FORW;
goto f_forw;
}
else {
dprintf(" %s\n", f->f_un.f_forw.f_hname);
dprintf("Forwarding suspension not over, time left: %d.\n",
INET_SUSPEND_TIME - fwd_suspend);
}
break;
/* The trick is to wait some time, then retry to get the
* address. If that fails retry x times and then give up.
*
* You'll run into this problem mostly if the name server you
* need for resolving the address is on the same machine, but
* is started after syslogd.
*/
case F_FORW_UNKN:
/* The remote address is not yet known and needs to be obtained */
dprintf(" %s\n", f->f_un.f_forw.f_hname);
fwd_suspend = time(NULL) - f->f_time;
if(fwd_suspend >= INET_SUSPEND_TIME) {
dprintf("Forwarding suspension to unknown over, retrying\n");
memset(&hints, 0, sizeof(hints));
/* port must be numeric, because config file syntax requests this */
/* TODO: this code is a duplicate from cfline() - we should later create
* a common function.
*/
hints.ai_flags = AI_NUMERICSERV;
hints.ai_family = family;
hints.ai_socktype = f->f_un.f_forw.protocol == FORW_UDP ? SOCK_DGRAM : SOCK_STREAM;
if((e = getaddrinfo(f->f_un.f_forw.f_hname,
getFwdSyslogPt(f), &hints, &res)) != 0) {
dprintf("Failure: %s\n", sys_h_errlist[h_errno]);
dprintf("Retries: %d\n", f->f_prevcount);
if ( --f->f_prevcount < 0 ) {
dprintf("Giving up.\n");
f->f_type = F_UNUSED;
}
else
dprintf("Left retries: %d\n", f->f_prevcount);
}
else {
dprintf("%s found, resuming.\n", f->f_un.f_forw.f_hname);
f->f_un.f_forw.f_addr = res;
f->f_prevcount = 0;
f->f_type = F_FORW;
goto f_forw;
}
}
else
dprintf("Forwarding suspension not over, time " \
"left: %d\n", INET_SUSPEND_TIME - fwd_suspend);
break;
case F_FORW:
f_forw:
dprintf(" %s:%s/%s\n", f->f_un.f_forw.f_hname, getFwdSyslogPt(f),
f->f_un.f_forw.protocol == FORW_UDP ? "udp" : "tcp");
iovCreate(f);
if ( strcmp(getHOSTNAME(f->f_pMsg), LocalHostName) && NoHops )
dprintf("Not sending message to remote.\n");
else {
f->f_time = now;
psz = iovAsString(f);
l = f->f_iLenpsziov;
if (l > MAXLINE)
l = MAXLINE;
# ifdef USE_NETZIP
/* Check if we should compress and, if so, do it. We also
* check if the message is large enough to justify compression.
* The smaller the message, the less likely is a gain in compression.
* To save CPU cycles, we do not try to compress very small messages.
* What "very small" means needs to be configured. Currently, it is
* hard-coded but this may be changed to a config parameter.
* rgerhards, 2006-11-30
*/
if(f->f_un.f_forw.compressionLevel && (l > MIN_SIZE_FOR_COMPRESS)) {
Bytef out[MAXLINE+MAXLINE/100+12] = "z";
uLongf destLen = sizeof(out) / sizeof(Bytef);
uLong srcLen = l;
int ret;
ret = compress2((Bytef*) out+1, &destLen, (Bytef*) psz,
srcLen, f->f_un.f_forw.compressionLevel);
dprintf("Compressing message, length was %d now %d, return state %d.\n",
l, (int) destLen, ret);
if(ret != Z_OK) {
/* if we fail, we complain, but only in debug mode
* Otherwise, we are silent. In any case, we ignore the
* failed compression and just sent the uncompressed
* data, which is still valid. So this is probably the
* best course of action.
* rgerhards, 2006-11-30
*/
dprintf("Compression failed, sending uncompressed message\n");
} else if(destLen+1 < l) {
/* only use compression if there is a gain in using it! */
dprintf("there is gain in compression, so we do it\n");
psz = (char*) out;
l = destLen + 1; /* take care for the "z" at message start! */
}
++destLen;
}
# endif
if(f->f_un.f_forw.protocol == FORW_UDP) {
/* forward via UDP */
if(finet != NULL) {
/* we need to track if we have success sending to the remote
* peer. Success is indicated by at least one sendto() call
* succeeding. We track this be bSendSuccess. We can not simply
* rely on lsent, as a call might initially work, but a later
* call fails. Then, lsent has the error status, even though
* the sendto() succeeded.
* rgerhards, 2007-06-22
*/
bSendSuccess = FALSE;
for (r = f->f_un.f_forw.f_addr; r; r = r->ai_next) {
for (i = 0; i < *finet; i++) {
lsent = sendto(finet[i+1], psz, l, 0,
r->ai_addr, r->ai_addrlen);
if (lsent == l) {
bSendSuccess = TRUE;
break;
} else {
int eno = errno;
dprintf("sendto() error: %d = %s.\n",
eno, strerror(eno));
}
}
if (lsent == l && !send_to_all)
break;
}
/* finished looping */
if (bSendSuccess == FALSE) {
f->f_type = F_FORW_SUSP;
errno = 0;
logerror("error forwarding via udp, suspending");
}
}
} else {
/* forward via TCP */
if(TCPSend(f, psz, l) != 0) {
/* error! */
f->f_type = F_FORW_SUSP;
errno = 0;
logerror("error forwarding via tcp, suspending...");
}
}
}
break;
}
return 0;
}
#endif /* #ifdef SYSLOG_INET */
/*
* vi:set ai:
*/
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