1 /**
2 * collectd - src/dns.c
3 * Copyright (C) 2006-2011 Florian octo Forster
4 * Copyright (C) 2009 Mirko Buffoni
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License as published by the
8 * Free Software Foundation; only version 2 of the License is applicable.
9 *
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License along
16 * with this program; if not, write to the Free Software Foundation, Inc.,
17 * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
18 *
19 * Authors:
20 * Florian octo Forster <octo at collectd.org>
21 * Mirko Buffoni <briareos at eswat.org>
22 **/
24 #define _DEFAULT_SOURCE
25 #define _BSD_SOURCE
27 #include "collectd.h"
28 #include "common.h"
29 #include "plugin.h"
30 #include "configfile.h"
32 #include "utils_dns.h"
33 #include <pthread.h>
34 #include <poll.h>
36 #include <pcap.h>
37 #include <pcap-bpf.h>
39 /*
40 * Private data types
41 */
42 struct counter_list_s
43 {
44 unsigned int key;
45 unsigned int value;
46 struct counter_list_s *next;
47 };
48 typedef struct counter_list_s counter_list_t;
50 /*
51 * Private variables
52 */
53 static const char *config_keys[] =
54 {
55 "Interface",
56 "IgnoreSource",
57 "SelectNumericQueryTypes"
58 };
59 static int config_keys_num = STATIC_ARRAY_SIZE (config_keys);
60 static int select_numeric_qtype = 1;
62 #define PCAP_SNAPLEN 1460
63 static char *pcap_device = NULL;
65 static derive_t tr_queries;
66 static derive_t tr_responses;
67 static counter_list_t *qtype_list;
68 static counter_list_t *opcode_list;
69 static counter_list_t *rcode_list;
71 static pthread_t listen_thread;
72 static int listen_thread_init = 0;
73 /* The `traffic' mutex if for `tr_queries' and `tr_responses' */
74 static pthread_mutex_t traffic_mutex = PTHREAD_MUTEX_INITIALIZER;
75 static pthread_mutex_t qtype_mutex = PTHREAD_MUTEX_INITIALIZER;
76 static pthread_mutex_t opcode_mutex = PTHREAD_MUTEX_INITIALIZER;
77 static pthread_mutex_t rcode_mutex = PTHREAD_MUTEX_INITIALIZER;
79 /*
80 * Private functions
81 */
82 static counter_list_t *counter_list_search (counter_list_t **list, unsigned int key)
83 {
84 counter_list_t *entry;
86 for (entry = *list; entry != NULL; entry = entry->next)
87 if (entry->key == key)
88 break;
90 return (entry);
91 }
93 static counter_list_t *counter_list_create (counter_list_t **list,
94 unsigned int key, unsigned int value)
95 {
96 counter_list_t *entry;
98 entry = (counter_list_t *) malloc (sizeof (counter_list_t));
99 if (entry == NULL)
100 return (NULL);
102 memset (entry, 0, sizeof (counter_list_t));
103 entry->key = key;
104 entry->value = value;
106 if (*list == NULL)
107 {
108 *list = entry;
109 }
110 else
111 {
112 counter_list_t *last;
114 last = *list;
115 while (last->next != NULL)
116 last = last->next;
118 last->next = entry;
119 }
121 return (entry);
122 }
124 static void counter_list_add (counter_list_t **list,
125 unsigned int key, unsigned int increment)
126 {
127 counter_list_t *entry;
129 entry = counter_list_search (list, key);
131 if (entry != NULL)
132 {
133 entry->value += increment;
134 }
135 else
136 {
137 counter_list_create (list, key, increment);
138 }
139 }
141 static int dns_config (const char *key, const char *value)
142 {
143 if (strcasecmp (key, "Interface") == 0)
144 {
145 if (pcap_device != NULL)
146 free (pcap_device);
147 if ((pcap_device = strdup (value)) == NULL)
148 return (1);
149 }
150 else if (strcasecmp (key, "IgnoreSource") == 0)
151 {
152 if (value != NULL)
153 ignore_list_add_name (value);
154 }
155 else if (strcasecmp (key, "SelectNumericQueryTypes") == 0)
156 {
157 if ((value != NULL) && IS_FALSE (value))
158 select_numeric_qtype = 0;
159 else
160 select_numeric_qtype = 1;
161 }
162 else
163 {
164 return (-1);
165 }
167 return (0);
168 }
170 static void dns_child_callback (const rfc1035_header_t *dns)
171 {
172 if (dns->qr == 0)
173 {
174 /* This is a query */
175 int skip = 0;
176 if (!select_numeric_qtype)
177 {
178 const char *str = qtype_str(dns->qtype);
179 if ((str == NULL) || (str[0] == '#'))
180 skip = 1;
181 }
183 pthread_mutex_lock (&traffic_mutex);
184 tr_queries += dns->length;
185 pthread_mutex_unlock (&traffic_mutex);
187 if (skip == 0)
188 {
189 pthread_mutex_lock (&qtype_mutex);
190 counter_list_add (&qtype_list, dns->qtype, 1);
191 pthread_mutex_unlock (&qtype_mutex);
192 }
193 }
194 else
195 {
196 /* This is a reply */
197 pthread_mutex_lock (&traffic_mutex);
198 tr_responses += dns->length;
199 pthread_mutex_unlock (&traffic_mutex);
201 pthread_mutex_lock (&rcode_mutex);
202 counter_list_add (&rcode_list, dns->rcode, 1);
203 pthread_mutex_unlock (&rcode_mutex);
204 }
206 /* FIXME: Are queries, replies or both interesting? */
207 pthread_mutex_lock (&opcode_mutex);
208 counter_list_add (&opcode_list, dns->opcode, 1);
209 pthread_mutex_unlock (&opcode_mutex);
210 }
212 static int dns_run_pcap_loop (void)
213 {
214 pcap_t *pcap_obj;
215 char pcap_error[PCAP_ERRBUF_SIZE];
216 struct bpf_program fp;
218 int status;
220 /* Don't block any signals */
221 {
222 sigset_t sigmask;
223 sigemptyset (&sigmask);
224 pthread_sigmask (SIG_SETMASK, &sigmask, NULL);
225 }
227 /* Passing `pcap_device == NULL' is okay and the same as passign "any" */
228 DEBUG ("dns plugin: Creating PCAP object..");
229 pcap_obj = pcap_open_live ((pcap_device != NULL) ? pcap_device : "any",
230 PCAP_SNAPLEN,
231 0 /* Not promiscuous */,
232 (int) CDTIME_T_TO_MS (plugin_get_interval () / 2),
233 pcap_error);
234 if (pcap_obj == NULL)
235 {
236 ERROR ("dns plugin: Opening interface `%s' "
237 "failed: %s",
238 (pcap_device != NULL) ? pcap_device : "any",
239 pcap_error);
240 return (PCAP_ERROR);
241 }
243 memset (&fp, 0, sizeof (fp));
244 status = pcap_compile (pcap_obj, &fp, "udp port 53", 1, 0);
245 if (status < 0)
246 {
247 ERROR ("dns plugin: pcap_compile failed: %s",
248 pcap_statustostr (status));
249 return (status);
250 }
252 status = pcap_setfilter (pcap_obj, &fp);
253 if (status < 0)
254 {
255 ERROR ("dns plugin: pcap_setfilter failed: %s",
256 pcap_statustostr (status));
257 return (status);
258 }
260 DEBUG ("dns plugin: PCAP object created.");
262 dnstop_set_pcap_obj (pcap_obj);
263 dnstop_set_callback (dns_child_callback);
265 status = pcap_loop (pcap_obj,
266 -1 /* loop forever */,
267 handle_pcap /* callback */,
268 NULL /* user data */);
269 INFO ("dns plugin: pcap_loop exited with status %i.", status);
270 /* We need to handle "PCAP_ERROR" specially because libpcap currently
271 * doesn't return PCAP_ERROR_IFACE_NOT_UP for compatibility reasons. */
272 if (status == PCAP_ERROR)
273 status = PCAP_ERROR_IFACE_NOT_UP;
275 pcap_close (pcap_obj);
276 return (status);
277 } /* int dns_run_pcap_loop */
279 static int dns_sleep_one_interval (void) /* {{{ */
280 {
281 cdtime_t interval;
282 struct timespec ts = { 0, 0 };
283 int status = 0;
285 interval = plugin_get_interval ();
286 CDTIME_T_TO_TIMESPEC (interval, &ts);
288 while (42)
289 {
290 struct timespec rem = { 0, 0 };
292 status = nanosleep (&ts, &rem);
293 if (status == 0)
294 break;
295 else if ((errno == EINTR) || (errno == EAGAIN))
296 {
297 ts = rem;
298 continue;
299 }
300 else
301 break;
302 }
304 return (status);
305 } /* }}} int dns_sleep_one_interval */
307 static void *dns_child_loop (__attribute__((unused)) void *dummy) /* {{{ */
308 {
309 int status;
311 while (42)
312 {
313 status = dns_run_pcap_loop ();
314 if (status != PCAP_ERROR_IFACE_NOT_UP)
315 break;
317 dns_sleep_one_interval ();
318 }
320 if (status != PCAP_ERROR_BREAK)
321 ERROR ("dns plugin: PCAP returned error %s.",
322 pcap_statustostr (status));
324 listen_thread_init = 0;
325 return (NULL);
326 } /* }}} void *dns_child_loop */
328 static int dns_init (void)
329 {
330 /* clean up an old thread */
331 int status;
333 pthread_mutex_lock (&traffic_mutex);
334 tr_queries = 0;
335 tr_responses = 0;
336 pthread_mutex_unlock (&traffic_mutex);
338 if (listen_thread_init != 0)
339 return (-1);
341 status = plugin_thread_create (&listen_thread, NULL, dns_child_loop,
342 (void *) 0);
343 if (status != 0)
344 {
345 char errbuf[1024];
346 ERROR ("dns plugin: pthread_create failed: %s",
347 sstrerror (errno, errbuf, sizeof (errbuf)));
348 return (-1);
349 }
351 listen_thread_init = 1;
353 return (0);
354 } /* int dns_init */
356 static void submit_derive (const char *type, const char *type_instance,
357 derive_t value)
358 {
359 value_t values[1];
360 value_list_t vl = VALUE_LIST_INIT;
362 values[0].derive = value;
364 vl.values = values;
365 vl.values_len = 1;
366 sstrncpy (vl.host, hostname_g, sizeof (vl.host));
367 sstrncpy (vl.plugin, "dns", sizeof (vl.plugin));
368 sstrncpy (vl.type, type, sizeof (vl.type));
369 sstrncpy (vl.type_instance, type_instance, sizeof (vl.type_instance));
371 plugin_dispatch_values (&vl);
372 } /* void submit_derive */
374 static void submit_octets (derive_t queries, derive_t responses)
375 {
376 value_t values[2];
377 value_list_t vl = VALUE_LIST_INIT;
379 values[0].derive = queries;
380 values[1].derive = responses;
382 vl.values = values;
383 vl.values_len = 2;
384 sstrncpy (vl.host, hostname_g, sizeof (vl.host));
385 sstrncpy (vl.plugin, "dns", sizeof (vl.plugin));
386 sstrncpy (vl.type, "dns_octets", sizeof (vl.type));
388 plugin_dispatch_values (&vl);
389 } /* void submit_octets */
391 static int dns_read (void)
392 {
393 unsigned int keys[T_MAX];
394 unsigned int values[T_MAX];
395 int len;
396 int i;
398 counter_list_t *ptr;
400 pthread_mutex_lock (&traffic_mutex);
401 values[0] = tr_queries;
402 values[1] = tr_responses;
403 pthread_mutex_unlock (&traffic_mutex);
405 if ((values[0] != 0) || (values[1] != 0))
406 submit_octets (values[0], values[1]);
408 pthread_mutex_lock (&qtype_mutex);
409 for (ptr = qtype_list, len = 0;
410 (ptr != NULL) && (len < T_MAX);
411 ptr = ptr->next, len++)
412 {
413 keys[len] = ptr->key;
414 values[len] = ptr->value;
415 }
416 pthread_mutex_unlock (&qtype_mutex);
418 for (i = 0; i < len; i++)
419 {
420 DEBUG ("dns plugin: qtype = %u; counter = %u;", keys[i], values[i]);
421 submit_derive ("dns_qtype", qtype_str (keys[i]), values[i]);
422 }
424 pthread_mutex_lock (&opcode_mutex);
425 for (ptr = opcode_list, len = 0;
426 (ptr != NULL) && (len < T_MAX);
427 ptr = ptr->next, len++)
428 {
429 keys[len] = ptr->key;
430 values[len] = ptr->value;
431 }
432 pthread_mutex_unlock (&opcode_mutex);
434 for (i = 0; i < len; i++)
435 {
436 DEBUG ("dns plugin: opcode = %u; counter = %u;", keys[i], values[i]);
437 submit_derive ("dns_opcode", opcode_str (keys[i]), values[i]);
438 }
440 pthread_mutex_lock (&rcode_mutex);
441 for (ptr = rcode_list, len = 0;
442 (ptr != NULL) && (len < T_MAX);
443 ptr = ptr->next, len++)
444 {
445 keys[len] = ptr->key;
446 values[len] = ptr->value;
447 }
448 pthread_mutex_unlock (&rcode_mutex);
450 for (i = 0; i < len; i++)
451 {
452 DEBUG ("dns plugin: rcode = %u; counter = %u;", keys[i], values[i]);
453 submit_derive ("dns_rcode", rcode_str (keys[i]), values[i]);
454 }
456 return (0);
457 } /* int dns_read */
459 void module_register (void)
460 {
461 plugin_register_config ("dns", dns_config, config_keys, config_keys_num);
462 plugin_register_init ("dns", dns_init);
463 plugin_register_read ("dns", dns_read);
464 } /* void module_register */