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dns.c
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dns.c
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/**
* collectd - src/dns.c
* Copyright (C) 2006-2011 Florian octo Forster
* Copyright (C) 2009 Mirko Buffoni
*
* 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; only version 2 of the License is applicable.
*
* 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.,
* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
* Authors:
* Florian octo Forster <octo at collectd.org>
* Mirko Buffoni <briareos at eswat.org>
**/
#define _DEFAULT_SOURCE
#define _BSD_SOURCE
#include "collectd.h"
#include "common.h"
#include "plugin.h"
#include "configfile.h"
#include "utils_dns.h"
#include <pthread.h>
#include <poll.h>
#include <pcap.h>
/*
* Private data types
*/
struct counter_list_s
{
unsigned int key;
unsigned int value;
struct counter_list_s *next;
};
typedef struct counter_list_s counter_list_t;
/*
* Private variables
*/
static const char *config_keys[] =
{
"Interface",
"IgnoreSource",
"SelectNumericQueryTypes"
};
static int config_keys_num = STATIC_ARRAY_SIZE (config_keys);
static int select_numeric_qtype = 1;
#define PCAP_SNAPLEN 1460
static char *pcap_device = NULL;
static derive_t tr_queries;
static derive_t tr_responses;
static counter_list_t *qtype_list;
static counter_list_t *opcode_list;
static counter_list_t *rcode_list;
static pthread_t listen_thread;
static int listen_thread_init = 0;
/* The `traffic' mutex if for `tr_queries' and `tr_responses' */
static pthread_mutex_t traffic_mutex = PTHREAD_MUTEX_INITIALIZER;
static pthread_mutex_t qtype_mutex = PTHREAD_MUTEX_INITIALIZER;
static pthread_mutex_t opcode_mutex = PTHREAD_MUTEX_INITIALIZER;
static pthread_mutex_t rcode_mutex = PTHREAD_MUTEX_INITIALIZER;
/*
* Private functions
*/
static counter_list_t *counter_list_search (counter_list_t **list, unsigned int key)
{
counter_list_t *entry;
for (entry = *list; entry != NULL; entry = entry->next)
if (entry->key == key)
break;
return (entry);
}
static counter_list_t *counter_list_create (counter_list_t **list,
unsigned int key, unsigned int value)
{
counter_list_t *entry;
entry = (counter_list_t *) malloc (sizeof (counter_list_t));
if (entry == NULL)
return (NULL);
memset (entry, 0, sizeof (counter_list_t));
entry->key = key;
entry->value = value;
if (*list == NULL)
{
*list = entry;
}
else
{
counter_list_t *last;
last = *list;
while (last->next != NULL)
last = last->next;
last->next = entry;
}
return (entry);
}
static void counter_list_add (counter_list_t **list,
unsigned int key, unsigned int increment)
{
counter_list_t *entry;
entry = counter_list_search (list, key);
if (entry != NULL)
{
entry->value += increment;
}
else
{
counter_list_create (list, key, increment);
}
}
static int dns_config (const char *key, const char *value)
{
if (strcasecmp (key, "Interface") == 0)
{
if (pcap_device != NULL)
free (pcap_device);
if ((pcap_device = strdup (value)) == NULL)
return (1);
}
else if (strcasecmp (key, "IgnoreSource") == 0)
{
if (value != NULL)
ignore_list_add_name (value);
}
else if (strcasecmp (key, "SelectNumericQueryTypes") == 0)
{
if ((value != NULL) && IS_FALSE (value))
select_numeric_qtype = 0;
else
select_numeric_qtype = 1;
}
else
{
return (-1);
}
return (0);
}
static void dns_child_callback (const rfc1035_header_t *dns)
{
if (dns->qr == 0)
{
/* This is a query */
int skip = 0;
if (!select_numeric_qtype)
{
const char *str = qtype_str(dns->qtype);
if ((str == NULL) || (str[0] == '#'))
skip = 1;
}
pthread_mutex_lock (&traffic_mutex);
tr_queries += dns->length;
pthread_mutex_unlock (&traffic_mutex);
if (skip == 0)
{
pthread_mutex_lock (&qtype_mutex);
counter_list_add (&qtype_list, dns->qtype, 1);
pthread_mutex_unlock (&qtype_mutex);
}
}
else
{
/* This is a reply */
pthread_mutex_lock (&traffic_mutex);
tr_responses += dns->length;
pthread_mutex_unlock (&traffic_mutex);
pthread_mutex_lock (&rcode_mutex);
counter_list_add (&rcode_list, dns->rcode, 1);
pthread_mutex_unlock (&rcode_mutex);
}
/* FIXME: Are queries, replies or both interesting? */
pthread_mutex_lock (&opcode_mutex);
counter_list_add (&opcode_list, dns->opcode, 1);
pthread_mutex_unlock (&opcode_mutex);
}
static int dns_run_pcap_loop (void)
{
pcap_t *pcap_obj;
char pcap_error[PCAP_ERRBUF_SIZE];
struct bpf_program fp;
int status;
/* Don't block any signals */
{
sigset_t sigmask;
sigemptyset (&sigmask);
pthread_sigmask (SIG_SETMASK, &sigmask, NULL);
}
/* Passing `pcap_device == NULL' is okay and the same as passign "any" */
DEBUG ("dns plugin: Creating PCAP object..");
pcap_obj = pcap_open_live ((pcap_device != NULL) ? pcap_device : "any",
PCAP_SNAPLEN,
0 /* Not promiscuous */,
(int) CDTIME_T_TO_MS (plugin_get_interval () / 2),
pcap_error);
if (pcap_obj == NULL)
{
ERROR ("dns plugin: Opening interface `%s' "
"failed: %s",
(pcap_device != NULL) ? pcap_device : "any",
pcap_error);
return (PCAP_ERROR);
}
memset (&fp, 0, sizeof (fp));
status = pcap_compile (pcap_obj, &fp, "udp port 53", 1, 0);
if (status < 0)
{
ERROR ("dns plugin: pcap_compile failed: %s",
pcap_statustostr (status));
return (status);
}
status = pcap_setfilter (pcap_obj, &fp);
if (status < 0)
{
ERROR ("dns plugin: pcap_setfilter failed: %s",
pcap_statustostr (status));
return (status);
}
DEBUG ("dns plugin: PCAP object created.");
dnstop_set_pcap_obj (pcap_obj);
dnstop_set_callback (dns_child_callback);
status = pcap_loop (pcap_obj,
-1 /* loop forever */,
handle_pcap /* callback */,
NULL /* user data */);
INFO ("dns plugin: pcap_loop exited with status %i.", status);
/* We need to handle "PCAP_ERROR" specially because libpcap currently
* doesn't return PCAP_ERROR_IFACE_NOT_UP for compatibility reasons. */
if (status == PCAP_ERROR)
status = PCAP_ERROR_IFACE_NOT_UP;
pcap_close (pcap_obj);
return (status);
} /* int dns_run_pcap_loop */
static int dns_sleep_one_interval (void) /* {{{ */
{
cdtime_t interval;
struct timespec ts = { 0, 0 };
int status = 0;
interval = plugin_get_interval ();
CDTIME_T_TO_TIMESPEC (interval, &ts);
while (42)
{
struct timespec rem = { 0, 0 };
status = nanosleep (&ts, &rem);
if (status == 0)
break;
else if ((errno == EINTR) || (errno == EAGAIN))
{
ts = rem;
continue;
}
else
break;
}
return (status);
} /* }}} int dns_sleep_one_interval */
static void *dns_child_loop (__attribute__((unused)) void *dummy) /* {{{ */
{
int status;
while (42)
{
status = dns_run_pcap_loop ();
if (status != PCAP_ERROR_IFACE_NOT_UP)
break;
dns_sleep_one_interval ();
}
if (status != PCAP_ERROR_BREAK)
ERROR ("dns plugin: PCAP returned error %s.",
pcap_statustostr (status));
listen_thread_init = 0;
return (NULL);
} /* }}} void *dns_child_loop */
static int dns_init (void)
{
/* clean up an old thread */
int status;
pthread_mutex_lock (&traffic_mutex);
tr_queries = 0;
tr_responses = 0;
pthread_mutex_unlock (&traffic_mutex);
if (listen_thread_init != 0)
return (-1);
status = plugin_thread_create (&listen_thread, NULL, dns_child_loop,
(void *) 0);
if (status != 0)
{
char errbuf[1024];
ERROR ("dns plugin: pthread_create failed: %s",
sstrerror (errno, errbuf, sizeof (errbuf)));
return (-1);
}
listen_thread_init = 1;
return (0);
} /* int dns_init */
static void submit_derive (const char *type, const char *type_instance,
derive_t value)
{
value_t values[1];
value_list_t vl = VALUE_LIST_INIT;
values[0].derive = value;
vl.values = values;
vl.values_len = 1;
sstrncpy (vl.host, hostname_g, sizeof (vl.host));
sstrncpy (vl.plugin, "dns", sizeof (vl.plugin));
sstrncpy (vl.type, type, sizeof (vl.type));
sstrncpy (vl.type_instance, type_instance, sizeof (vl.type_instance));
plugin_dispatch_values (&vl);
} /* void submit_derive */
static void submit_octets (derive_t queries, derive_t responses)
{
value_t values[2];
value_list_t vl = VALUE_LIST_INIT;
values[0].derive = queries;
values[1].derive = responses;
vl.values = values;
vl.values_len = 2;
sstrncpy (vl.host, hostname_g, sizeof (vl.host));
sstrncpy (vl.plugin, "dns", sizeof (vl.plugin));
sstrncpy (vl.type, "dns_octets", sizeof (vl.type));
plugin_dispatch_values (&vl);
} /* void submit_octets */
static int dns_read (void)
{
unsigned int keys[T_MAX];
unsigned int values[T_MAX];
int len;
int i;
counter_list_t *ptr;
pthread_mutex_lock (&traffic_mutex);
values[0] = tr_queries;
values[1] = tr_responses;
pthread_mutex_unlock (&traffic_mutex);
if ((values[0] != 0) || (values[1] != 0))
submit_octets (values[0], values[1]);
pthread_mutex_lock (&qtype_mutex);
for (ptr = qtype_list, len = 0;
(ptr != NULL) && (len < T_MAX);
ptr = ptr->next, len++)
{
keys[len] = ptr->key;
values[len] = ptr->value;
}
pthread_mutex_unlock (&qtype_mutex);
for (i = 0; i < len; i++)
{
DEBUG ("dns plugin: qtype = %u; counter = %u;", keys[i], values[i]);
submit_derive ("dns_qtype", qtype_str (keys[i]), values[i]);
}
pthread_mutex_lock (&opcode_mutex);
for (ptr = opcode_list, len = 0;
(ptr != NULL) && (len < T_MAX);
ptr = ptr->next, len++)
{
keys[len] = ptr->key;
values[len] = ptr->value;
}
pthread_mutex_unlock (&opcode_mutex);
for (i = 0; i < len; i++)
{
DEBUG ("dns plugin: opcode = %u; counter = %u;", keys[i], values[i]);
submit_derive ("dns_opcode", opcode_str (keys[i]), values[i]);
}
pthread_mutex_lock (&rcode_mutex);
for (ptr = rcode_list, len = 0;
(ptr != NULL) && (len < T_MAX);
ptr = ptr->next, len++)
{
keys[len] = ptr->key;
values[len] = ptr->value;
}
pthread_mutex_unlock (&rcode_mutex);
for (i = 0; i < len; i++)
{
DEBUG ("dns plugin: rcode = %u; counter = %u;", keys[i], values[i]);
submit_derive ("dns_rcode", rcode_str (keys[i]), values[i]);
}
return (0);
} /* int dns_read */
void module_register (void)
{
plugin_register_config ("dns", dns_config, config_keys, config_keys_num);
plugin_register_init ("dns", dns_init);
plugin_register_read ("dns", dns_read);
} /* void module_register */