summaryrefslogtreecommitdiffstats
path: root/plugins/imudp/imudp.c
blob: 64413e453f246d532e272ffc10944527a17efd71 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
/* imudp.c
 * This is the implementation of the UDP input module.
 *
 * NOTE: read comments in module-template.h to understand how this file
 *       works!
 *
 * File begun on 2007-12-21 by RGerhards (extracted from syslogd.c)
 *
 * Copyright 2007 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 <stdlib.h>
#include <assert.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <netdb.h>
#include "rsyslog.h"
#include "dirty.h"
#include "net.h"
#include "cfsysline.h"
#include "module-template.h"
#include "srUtils.h"
#include "errmsg.h"
#include "glbl.h"

MODULE_TYPE_INPUT

/* defines */

/* Module static data */
DEF_IMOD_STATIC_DATA
DEFobjCurrIf(errmsg)
DEFobjCurrIf(glbl)
DEFobjCurrIf(net)

static int iMaxLine;			/* maximum UDP message size supported */
static int *udpLstnSocks = NULL;	/* Internet datagram sockets, first element is nbr of elements
					 * read-only after init(), but beware of restart! */
static uchar *pszBindAddr = NULL;	/* IP to bind socket to */
static uchar *pRcvBuf = NULL;		/* receive buffer (for a single packet). We use a global and alloc
					 * it so that we can check available memory in willRun() and request
					 * termination if we can not get it. -- rgerhards, 2007-12-27
					 */

/* config settings */


/* This function is called when a new listener shall be added. It takes
 * the configured parameters, tries to bind the socket and, if that
 * succeeds, adds it to the list of existing listen sockets.
 * rgerhards, 2007-12-27
 */
static rsRetVal addListner(void __attribute__((unused)) *pVal, uchar *pNewVal)
{
	DEFiRet;
	uchar *bindAddr;
	int *newSocks;
	int *tmpSocks;
	int iSrc, iDst;

	/* check which address to bind to. We could do this more compact, but have not
	 * done so in order to make the code more readable. -- rgerhards, 2007-12-27
	 */
	if(pszBindAddr == NULL)
		bindAddr = NULL;
	else if(pszBindAddr[0] == '*' && pszBindAddr[1] == '\0')
		bindAddr = NULL;
	else
		bindAddr = pszBindAddr;

	dbgprintf("Trying to open syslog UDP ports at %s:%s.\n",
		  (bindAddr == NULL) ? (uchar*)"*" : bindAddr, pNewVal);

	newSocks = net.create_udp_socket(bindAddr, (pNewVal == NULL || *pNewVal == '\0') ? (uchar*) "514" : pNewVal, 1);
	if(newSocks != NULL) {
		/* we now need to add the new sockets to the existing set */
		if(udpLstnSocks == NULL) {
			/* esay, we can just replace it */
			udpLstnSocks = newSocks;
		} else {
			/* we need to add them */
			if((tmpSocks = malloc(sizeof(int) * 1 + newSocks[0] + udpLstnSocks[0])) == NULL) {
				dbgprintf("out of memory trying to allocate udp listen socket array\n");
				/* in this case, we discard the new sockets but continue with what we
				 * already have
				 */
				free(newSocks);
				ABORT_FINALIZE(RS_RET_OUT_OF_MEMORY);
			} else {
				/* ready to copy */
				iDst = 1;
				for(iSrc = 1 ; iSrc <= udpLstnSocks[0] ; ++iSrc)
					tmpSocks[iDst++] = udpLstnSocks[iSrc];
				for(iSrc = 1 ; iSrc <= newSocks[0] ; ++iSrc)
					tmpSocks[iDst++] = newSocks[iSrc];
				tmpSocks[0] = udpLstnSocks[0] + newSocks[0];
				free(newSocks);
				free(udpLstnSocks);
				udpLstnSocks = tmpSocks;
			}
		}
	}

finalize_it:
	free(pNewVal); /* in any case, this is no longer needed */

	RETiRet;
}


/* This function is called to gather input.
 */
BEGINrunInput
	int maxfds;
	int nfds;
	int i;
	fd_set readfds;
	struct sockaddr_storage frominet;
	socklen_t socklen;
	uchar fromHost[NI_MAXHOST];
	uchar fromHostIP[NI_MAXHOST];
	uchar fromHostFQDN[NI_MAXHOST];
	ssize_t l;
CODESTARTrunInput
	/* this is an endless loop - it is terminated when the thread is
	 * signalled to do so. This, however, is handled by the framework,
	 * right into the sleep below.
	 */
	while(1) {
		/* Add the Unix Domain Sockets to the list of read
		 * descriptors.
		 * rgerhards 2005-08-01: we must now check if there are
		 * any local sockets to listen to at all. If the -o option
		 * is given without -a, we do not need to listen at all..
		 */
	        maxfds = 0;
	        FD_ZERO (&readfds);

		/* Add the UDP listen sockets to the list of read descriptors.
		 */
		if(udpLstnSocks != NULL) {
                        for (i = 0; i < *udpLstnSocks; i++) {
                                if (udpLstnSocks[i+1] != -1) {
					if(Debug)
						net.debugListenInfo(udpLstnSocks[i+1], "UDP");
                                        FD_SET(udpLstnSocks[i+1], &readfds);
					if(udpLstnSocks[i+1]>maxfds) maxfds=udpLstnSocks[i+1];
				}
                        }
		}
		if(Debug) {
			dbgprintf("--------imUDP calling select, active file descriptors (max %d): ", maxfds);
			for (nfds = 0; nfds <= maxfds; ++nfds)
				if ( FD_ISSET(nfds, &readfds) )
					dbgprintf("%d ", nfds);
			dbgprintf("\n");
		}

		/* wait for io to become ready */
		nfds = select(maxfds+1, (fd_set *) &readfds, NULL, NULL, NULL);

		if(udpLstnSocks != NULL) {
		       for (i = 0; nfds && i < *udpLstnSocks; i++) {
			       if (FD_ISSET(udpLstnSocks[i+1], &readfds)) {
				       socklen = sizeof(frominet);
				       l = recvfrom(udpLstnSocks[i+1], (char*) pRcvBuf, iMaxLine, 0,
						    (struct sockaddr *)&frominet, &socklen);
				       if (l > 0) {
					       if(net.cvthname(&frominet, fromHost, fromHostFQDN, fromHostIP) == RS_RET_OK) {
						       dbgprintf("Message from inetd socket: #%d, host: %s\n",
							       udpLstnSocks[i+1], fromHost);
						       /* Here we check if a host is permitted to send us
							* syslog messages. If it isn't, we do not further
							* process the message but log a warning (if we are
							* configured to do this).
							* rgerhards, 2005-09-26
							*/
						       if(net.isAllowedSender(net.pAllowedSenders_UDP,
							  (struct sockaddr *)&frominet, (char*)fromHostFQDN)) {
							       parseAndSubmitMessage(fromHost, fromHostIP, pRcvBuf, l,
							       MSG_PARSE_HOSTNAME, NOFLAG, eFLOWCTL_NO_DELAY, (uchar*)"imudp");
						       } else {
							       dbgprintf("%s is not an allowed sender\n", (char*)fromHostFQDN);
							       if(glbl.GetOption_DisallowWarning) {
								       errmsg.LogError(0, NO_ERRCODE, "UDP message from disallowed sender %s discarded",
										  (char*)fromHost);
							       }	
						       }
					       }
				       } else if (l < 0 && errno != EINTR && errno != EAGAIN) {
						char errStr[1024];
						rs_strerror_r(errno, errStr, sizeof(errStr));
						dbgprintf("INET socket error: %d = %s.\n", errno, errStr);
						       errmsg.LogError(errno, NO_ERRCODE, "recvfrom inet");
						       /* should be harmless */
						       sleep(1);
					       }
					--nfds; /* indicate we have processed one */
				}
		       }
		}
	}

	return iRet;
ENDrunInput


/* initialize and return if will run or not */
BEGINwillRun
CODESTARTwillRun
	net.PrintAllowedSenders(1); /* UDP */

	/* if we could not set up any listners, there is no point in running... */
	if(udpLstnSocks == NULL)
		ABORT_FINALIZE(RS_RET_NO_RUN);

	iMaxLine = glbl.GetMaxLine();

	if((pRcvBuf = malloc((iMaxLine + 1) * sizeof(char))) == NULL) {
		ABORT_FINALIZE(RS_RET_OUT_OF_MEMORY);
	}
finalize_it:
ENDwillRun


BEGINafterRun
CODESTARTafterRun
	/* do cleanup here */
	if (net.pAllowedSenders_UDP != NULL) {
		net.clearAllowedSenders (net.pAllowedSenders_UDP);
		net.pAllowedSenders_UDP = NULL;
	}
	if(udpLstnSocks != NULL)
		net.closeUDPListenSockets(udpLstnSocks);
	if(pRcvBuf != NULL)
		free(pRcvBuf);
ENDafterRun


BEGINmodExit
CODESTARTmodExit
	/* release what we no longer need */
	objRelease(errmsg, CORE_COMPONENT);
	objRelease(glbl, CORE_COMPONENT);
	objRelease(net, LM_NET_FILENAME);
ENDmodExit


BEGINqueryEtryPt
CODESTARTqueryEtryPt
CODEqueryEtryPt_STD_IMOD_QUERIES
ENDqueryEtryPt

static rsRetVal resetConfigVariables(uchar __attribute__((unused)) *pp, void __attribute__((unused)) *pVal)
{
	if(pszBindAddr != NULL) {
		free(pszBindAddr);
		pszBindAddr = NULL;
	}
	if(udpLstnSocks != NULL) {
		net.closeUDPListenSockets(udpLstnSocks);
		udpLstnSocks = NULL;
	}
	return RS_RET_OK;
}


BEGINmodInit()
CODESTARTmodInit
	*ipIFVersProvided = CURR_MOD_IF_VERSION; /* we only support the current interface specification */
CODEmodInit_QueryRegCFSLineHdlr
	CHKiRet(objUse(errmsg, CORE_COMPONENT));
	CHKiRet(objUse(glbl, CORE_COMPONENT));
	CHKiRet(objUse(net, LM_NET_FILENAME));

	/* register config file handlers */
	CHKiRet(omsdRegCFSLineHdlr((uchar *)"udpserverrun", 0, eCmdHdlrGetWord,
		addListner, NULL, STD_LOADABLE_MODULE_ID));
	CHKiRet(omsdRegCFSLineHdlr((uchar *)"udpserveraddress", 0, eCmdHdlrGetWord,
		NULL, &pszBindAddr, STD_LOADABLE_MODULE_ID));
	CHKiRet(omsdRegCFSLineHdlr((uchar *)"resetconfigvariables", 1, eCmdHdlrCustomHandler,
		resetConfigVariables, NULL, STD_LOADABLE_MODULE_ID));
ENDmodInit
/*
 * vi:set ai:
 */