Replace all occurrences of `strcpy' with `sstrncpy'.
[collectd.git] / src / network.c
index 32af404..022e46a 100644 (file)
@@ -1,11 +1,10 @@
 /**
  * collectd - src/network.c
- * Copyright (C) 2005,2006  Florian octo Forster
+ * Copyright (C) 2005-2008  Florian octo Forster
  *
  * 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.
+ * 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
  *   Florian octo Forster <octo at verplant.org>
  **/
 
-#if HAVE_CONFIG_H
-# include "config.h"
-#endif
-
-#include <stdlib.h>
-#include <stdio.h>
-#include <string.h>
-#include <sys/types.h>
-#include <sys/socket.h>
-#include <netdb.h>
-#include <netinet/in.h>
-#include <arpa/inet.h>
-#include <syslog.h>
-#include <errno.h>
-
-#include "network.h"
+#include "collectd.h"
+#include "plugin.h"
 #include "common.h"
 #include "configfile.h"
-#include "utils_debug.h"
+#include "utils_avltree.h"
+
+#include "network.h"
+
+#if HAVE_PTHREAD_H
+# include <pthread.h>
+#endif
+#if HAVE_SYS_SOCKET_H
+# include <sys/socket.h>
+#endif
+#if HAVE_NETDB_H
+# include <netdb.h>
+#endif
+#if HAVE_NETINET_IN_H
+# include <netinet/in.h>
+#endif
+#if HAVE_ARPA_INET_H
+# include <arpa/inet.h>
+#endif
+#if HAVE_POLL_H
+# include <poll.h>
+#endif
 
 /* 1500 - 40 - 8  =  Ethernet packet - IPv6 header - UDP header */
 /* #define BUFF_SIZE 1452 */
 # endif
 #endif /* !IP_ADD_MEMBERSHIP */
 
-#define BUFF_SIZE 4096
-
-extern int operating_mode;
+#define BUFF_SIZE 1024
 
+/*
+ * Private data types
+ */
 typedef struct sockent
 {
        int                      fd;
-       int                      mode;
        struct sockaddr_storage *addr;
        socklen_t                addrlen;
        struct sockent          *next;
 } sockent_t;
 
-static sockent_t *socklist_head = NULL;
+/*                      1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
+ *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-------+-----------------------+-------------------------------+
+ * ! Ver.  !                       ! Length                        !
+ * +-------+-----------------------+-------------------------------+
+ */
+struct part_header_s
+{
+       uint16_t type;
+       uint16_t length;
+};
+typedef struct part_header_s part_header_t;
+
+/*                      1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
+ *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-------------------------------+-------------------------------+
+ * ! Type                          ! Length                        !
+ * +-------------------------------+-------------------------------+
+ * : (Length - 4) Bytes                                            :
+ * +---------------------------------------------------------------+
+ */
+struct part_string_s
+{
+       part_header_t *head;
+       char *value;
+};
+typedef struct part_string_s part_string_t;
+
+/*                      1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
+ *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-------------------------------+-------------------------------+
+ * ! Type                          ! Length                        !
+ * +-------------------------------+-------------------------------+
+ * : (Length - 4 == 2 || 4 || 8) Bytes                             :
+ * +---------------------------------------------------------------+
+ */
+struct part_number_s
+{
+       part_header_t *head;
+       uint64_t *value;
+};
+typedef struct part_number_s part_number_t;
+
+/*                      1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
+ *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-------------------------------+-------------------------------+
+ * ! Type                          ! Length                        !
+ * +-------------------------------+---------------+---------------+
+ * ! Num of values                 ! Type0         ! Type1         !
+ * +-------------------------------+---------------+---------------+
+ * ! Value0                                                        !
+ * !                                                               !
+ * +---------------------------------------------------------------+
+ * ! Value1                                                        !
+ * !                                                               !
+ * +---------------------------------------------------------------+
+ */
+struct part_values_s
+{
+       part_header_t *head;
+       uint16_t *num_values;
+       uint8_t  *values_types;
+       value_t  *values;
+};
+typedef struct part_values_s part_values_t;
+
+struct receive_list_entry_s
+{
+  char data[BUFF_SIZE];
+  int  data_len;
+  struct receive_list_entry_s *next;
+};
+typedef struct receive_list_entry_s receive_list_entry_t;
+
+/*
+ * Private variables
+ */
+static const char *config_keys[] =
+{
+       "CacheFlush",
+       "Listen",
+       "Server",
+       "TimeToLive",
+       "Forward"
+};
+static int config_keys_num = STATIC_ARRAY_SIZE (config_keys);
+
+static int network_config_ttl = 0;
+static int network_config_forward = 0;
+
+static sockent_t *sending_sockets = NULL;
+
+static receive_list_entry_t *receive_list_head = NULL;
+static receive_list_entry_t *receive_list_tail = NULL;
+static pthread_mutex_t       receive_list_lock = PTHREAD_MUTEX_INITIALIZER;
+static pthread_cond_t        receive_list_cond = PTHREAD_COND_INITIALIZER;
+
+static struct pollfd *listen_sockets = NULL;
+static int listen_sockets_num = 0;
+
+static int listen_loop = 0;
+static pthread_t receive_thread_id = 0;
+static pthread_t dispatch_thread_id = 0;
+
+static char         send_buffer[BUFF_SIZE];
+static char        *send_buffer_ptr;
+static int          send_buffer_fill;
+static value_list_t send_buffer_vl = VALUE_LIST_STATIC;
+static char         send_buffer_type[DATA_MAX_NAME_LEN];
+static pthread_mutex_t send_buffer_lock = PTHREAD_MUTEX_INITIALIZER;
+
+static c_avl_tree_t      *cache_tree = NULL;
+static pthread_mutex_t  cache_lock = PTHREAD_MUTEX_INITIALIZER;
+static time_t           cache_flush_last = 0;
+static int              cache_flush_interval = 1800;
+
+/*
+ * Private functions
+ */
+static int cache_flush (void)
+{
+       char **keys = NULL;
+       int    keys_num = 0;
 
-static int network_set_ttl (const sockent_t *se, const struct addrinfo *ai)
+       char **tmp;
+       int    i;
+
+       char   *key;
+       time_t *value;
+       c_avl_iterator_t *iter;
+
+       time_t curtime = time (NULL);
+
+       iter = c_avl_get_iterator (cache_tree);
+       while (c_avl_iterator_next (iter, (void *) &key, (void *) &value) == 0)
+       {
+               if ((curtime - *value) <= cache_flush_interval)
+                       continue;
+               tmp = (char **) realloc (keys,
+                               (keys_num + 1) * sizeof (char *));
+               if (tmp == NULL)
+               {
+                       sfree (keys);
+                       c_avl_iterator_destroy (iter);
+                       ERROR ("network plugin: cache_flush: realloc"
+                                       " failed.");
+                       return (-1);
+               }
+               keys = tmp;
+               keys[keys_num] = key;
+               keys_num++;
+       } /* while (c_avl_iterator_next) */
+       c_avl_iterator_destroy (iter);
+
+       for (i = 0; i < keys_num; i++)
+       {
+               if (c_avl_remove (cache_tree, keys[i], (void *) &key,
+                                       (void *) &value) != 0)
+               {
+                       WARNING ("network plugin: cache_flush: c_avl_remove"
+                                       " (%s) failed.", keys[i]);
+                       continue;
+               }
+
+               sfree (key);
+               sfree (value);
+       }
+
+       sfree (keys);
+
+       DEBUG ("network plugin: cache_flush: Removed %i %s",
+                       keys_num, (keys_num == 1) ? "entry" : "entries");
+       cache_flush_last = curtime;
+       return (0);
+} /* int cache_flush */
+
+static int cache_check (const char *type, const value_list_t *vl)
+{
+       char key[1024];
+       time_t *value = NULL;
+       int retval = -1;
+
+       if (cache_tree == NULL)
+               return (-1);
+
+       if (format_name (key, sizeof (key), vl->host, vl->plugin,
+                               vl->plugin_instance, type, vl->type_instance))
+               return (-1);
+
+       pthread_mutex_lock (&cache_lock);
+
+       if (c_avl_get (cache_tree, key, (void *) &value) == 0)
+       {
+               if (*value < vl->time)
+               {
+                       *value = vl->time;
+                       retval = 0;
+               }
+               else
+               {
+                       DEBUG ("network plugin: cache_check: *value = %i >= vl->time = %i",
+                                       (int) *value, (int) vl->time);
+                       retval = 1;
+               }
+       }
+       else
+       {
+               char *key_copy = strdup (key);
+               value = malloc (sizeof (time_t));
+               if ((key_copy != NULL) && (value != NULL))
+               {
+                       *value = vl->time;
+                       c_avl_insert (cache_tree, key_copy, value);
+                       retval = 0;
+               }
+               else
+               {
+                       sfree (key_copy);
+                       sfree (value);
+               }
+       }
+
+       if ((time (NULL) - cache_flush_last) > cache_flush_interval)
+               cache_flush ();
+
+       pthread_mutex_unlock (&cache_lock);
+
+       DEBUG ("network plugin: cache_check: key = %s; time = %i; retval = %i",
+                       key, (int) vl->time, retval);
+
+       return (retval);
+} /* int cache_check */
+
+static int write_part_values (char **ret_buffer, int *ret_buffer_len,
+               const data_set_t *ds, const value_list_t *vl)
 {
-       char *ttl_str;
-       int   ttl_int;
+       char *packet_ptr;
+       int packet_len;
+       int num_values;
+
+       part_header_t pkg_ph;
+       uint16_t      pkg_num_values;
+       uint8_t      *pkg_values_types;
+       value_t      *pkg_values;
+
+       int offset;
+       int i;
 
-       ttl_str = cf_get_option ("TimeToLive", NULL);
-       if (ttl_str == NULL)
+       num_values = vl->values_len;
+       packet_len = sizeof (part_header_t) + sizeof (uint16_t)
+               + (num_values * sizeof (uint8_t))
+               + (num_values * sizeof (value_t));
+
+       if (*ret_buffer_len < packet_len)
                return (-1);
 
-       ttl_int = atoi (ttl_str);
-       if ((ttl_int < 1) || (ttl_int > 255))
+       pkg_values_types = (uint8_t *) malloc (num_values * sizeof (uint8_t));
+       if (pkg_values_types == NULL)
        {
-               syslog (LOG_WARNING, "A TTL value of %i is invalid.", ttl_int);
+               ERROR ("network plugin: write_part_values: malloc failed.");
                return (-1);
        }
 
-       DBG ("ttl = %i", ttl_int);
+       pkg_values = (value_t *) malloc (num_values * sizeof (value_t));
+       if (pkg_values == NULL)
+       {
+               free (pkg_values_types);
+               ERROR ("network plugin: write_part_values: malloc failed.");
+               return (-1);
+       }
+
+       pkg_ph.type = htons (TYPE_VALUES);
+       pkg_ph.length = htons (packet_len);
+
+       pkg_num_values = htons ((uint16_t) vl->values_len);
+
+       for (i = 0; i < num_values; i++)
+       {
+               if (ds->ds[i].type == DS_TYPE_COUNTER)
+               {
+                       pkg_values_types[i] = DS_TYPE_COUNTER;
+                       pkg_values[i].counter = htonll (vl->values[i].counter);
+               }
+               else
+               {
+                       pkg_values_types[i] = DS_TYPE_GAUGE;
+                       pkg_values[i].gauge = htond (vl->values[i].gauge);
+               }
+       }
+
+       /*
+        * Use `memcpy' to write everything to the buffer, because the pointer
+        * may be unaligned and some architectures, such as SPARC, can't handle
+        * that.
+        */
+       packet_ptr = *ret_buffer;
+       offset = 0;
+       memcpy (packet_ptr + offset, &pkg_ph, sizeof (pkg_ph));
+       offset += sizeof (pkg_ph);
+       memcpy (packet_ptr + offset, &pkg_num_values, sizeof (pkg_num_values));
+       offset += sizeof (pkg_num_values);
+       memcpy (packet_ptr + offset, pkg_values_types, num_values * sizeof (uint8_t));
+       offset += num_values * sizeof (uint8_t);
+       memcpy (packet_ptr + offset, pkg_values, num_values * sizeof (value_t));
+       offset += num_values * sizeof (value_t);
+
+       assert (offset == packet_len);
+
+       *ret_buffer = packet_ptr + packet_len;
+       *ret_buffer_len -= packet_len;
+
+       free (pkg_values_types);
+       free (pkg_values);
+
+       return (0);
+} /* int write_part_values */
+
+static int write_part_number (char **ret_buffer, int *ret_buffer_len,
+               int type, uint64_t value)
+{
+       char *packet_ptr;
+       int packet_len;
+
+       part_header_t pkg_head;
+       uint64_t pkg_value;
+       
+       int offset;
+
+       packet_len = sizeof (pkg_head) + sizeof (pkg_value);
+
+       if (*ret_buffer_len < packet_len)
+               return (-1);
+
+       pkg_head.type = htons (type);
+       pkg_head.length = htons (packet_len);
+       pkg_value = htonll (value);
+
+       packet_ptr = *ret_buffer;
+       offset = 0;
+       memcpy (packet_ptr + offset, &pkg_head, sizeof (pkg_head));
+       offset += sizeof (pkg_head);
+       memcpy (packet_ptr + offset, &pkg_value, sizeof (pkg_value));
+       offset += sizeof (pkg_value);
+
+       assert (offset == packet_len);
+
+       *ret_buffer = packet_ptr + packet_len;
+       *ret_buffer_len -= packet_len;
+
+       return (0);
+} /* int write_part_number */
+
+static int write_part_string (char **ret_buffer, int *ret_buffer_len,
+               int type, const char *str, int str_len)
+{
+       char *buffer;
+       int buffer_len;
+
+       uint16_t pkg_type;
+       uint16_t pkg_length;
+
+       int offset;
+
+       buffer_len = 2 * sizeof (uint16_t) + str_len + 1;
+       if (*ret_buffer_len < buffer_len)
+               return (-1);
+
+       pkg_type = htons (type);
+       pkg_length = htons (buffer_len);
+
+       buffer = *ret_buffer;
+       offset = 0;
+       memcpy (buffer + offset, (void *) &pkg_type, sizeof (pkg_type));
+       offset += sizeof (pkg_type);
+       memcpy (buffer + offset, (void *) &pkg_length, sizeof (pkg_length));
+       offset += sizeof (pkg_length);
+       memcpy (buffer + offset, str, str_len);
+       offset += str_len;
+       memset (buffer + offset, '\0', 1);
+       offset += 1;
+
+       assert (offset == buffer_len);
+
+       *ret_buffer = buffer + buffer_len;
+       *ret_buffer_len -= buffer_len;
+
+       return (0);
+} /* int write_part_string */
+
+static int parse_part_values (void **ret_buffer, int *ret_buffer_len,
+               value_t **ret_values, int *ret_num_values)
+{
+       char *buffer = *ret_buffer;
+       int   buffer_len = *ret_buffer_len;
+
+       uint16_t tmp16;
+       size_t exp_size;
+       int   i;
+
+       uint16_t pkg_length;
+       uint16_t pkg_type;
+       uint16_t pkg_numval;
+
+       uint8_t *pkg_types;
+       value_t *pkg_values;
+
+       if (buffer_len < (15))
+       {
+               DEBUG ("network plugin: packet is too short: buffer_len = %i",
+                               buffer_len);
+               return (-1);
+       }
+
+       memcpy ((void *) &tmp16, buffer, sizeof (tmp16));
+       buffer += sizeof (tmp16);
+       pkg_type = ntohs (tmp16);
+
+       memcpy ((void *) &tmp16, buffer, sizeof (tmp16));
+       buffer += sizeof (tmp16);
+       pkg_length = ntohs (tmp16);
+
+       memcpy ((void *) &tmp16, buffer, sizeof (tmp16));
+       buffer += sizeof (tmp16);
+       pkg_numval = ntohs (tmp16);
+
+       assert (pkg_type == TYPE_VALUES);
+
+       exp_size = 3 * sizeof (uint16_t)
+               + pkg_numval * (sizeof (uint8_t) + sizeof (value_t));
+       if (buffer_len < exp_size)
+       {
+               WARNING ("network plugin: parse_part_values: "
+                               "Packet too short: "
+                               "Chunk of size %u expected, "
+                               "but buffer has only %i bytes left.",
+                               (unsigned int) exp_size, buffer_len);
+               return (-1);
+       }
+
+       if (pkg_length != exp_size)
+       {
+               WARNING ("network plugin: parse_part_values: "
+                               "Length and number of values "
+                               "in the packet don't match.");
+               return (-1);
+       }
+
+       pkg_types = (uint8_t *) malloc (pkg_numval * sizeof (uint8_t));
+       pkg_values = (value_t *) malloc (pkg_numval * sizeof (value_t));
+       if ((pkg_types == NULL) || (pkg_values == NULL))
+       {
+               sfree (pkg_types);
+               sfree (pkg_values);
+               ERROR ("network plugin: parse_part_values: malloc failed.");
+               return (-1);
+       }
+
+       memcpy ((void *) pkg_types, (void *) buffer, pkg_numval * sizeof (uint8_t));
+       buffer += pkg_numval * sizeof (uint8_t);
+       memcpy ((void *) pkg_values, (void *) buffer, pkg_numval * sizeof (value_t));
+       buffer += pkg_numval * sizeof (value_t);
+
+       for (i = 0; i < pkg_numval; i++)
+       {
+               if (pkg_types[i] == DS_TYPE_COUNTER)
+                       pkg_values[i].counter = ntohll (pkg_values[i].counter);
+               else if (pkg_types[i] == DS_TYPE_GAUGE)
+                       pkg_values[i].gauge = ntohd (pkg_values[i].gauge);
+       }
+
+       *ret_buffer     = buffer;
+       *ret_buffer_len = buffer_len - pkg_length;
+       *ret_num_values = pkg_numval;
+       *ret_values     = pkg_values;
+
+       sfree (pkg_types);
+
+       return (0);
+} /* int parse_part_values */
+
+static int parse_part_number (void **ret_buffer, int *ret_buffer_len,
+               uint64_t *value)
+{
+       char *buffer = *ret_buffer;
+       int buffer_len = *ret_buffer_len;
+
+       uint16_t tmp16;
+       uint64_t tmp64;
+       size_t exp_size = 2 * sizeof (uint16_t) + sizeof (uint64_t);
+
+       uint16_t pkg_length;
+       uint16_t pkg_type;
+
+       if (buffer_len < exp_size)
+       {
+               WARNING ("network plugin: parse_part_number: "
+                               "Packet too short: "
+                               "Chunk of size %u expected, "
+                               "but buffer has only %i bytes left.",
+                               (unsigned int) exp_size, buffer_len);
+               return (-1);
+       }
+
+       memcpy ((void *) &tmp16, buffer, sizeof (tmp16));
+       buffer += sizeof (tmp16);
+       pkg_type = ntohs (tmp16);
+
+       memcpy ((void *) &tmp16, buffer, sizeof (tmp16));
+       buffer += sizeof (tmp16);
+       pkg_length = ntohs (tmp16);
+
+       memcpy ((void *) &tmp64, buffer, sizeof (tmp64));
+       buffer += sizeof (tmp64);
+       *value = ntohll (tmp64);
+
+       *ret_buffer = buffer;
+       *ret_buffer_len = buffer_len - pkg_length;
+
+       return (0);
+} /* int parse_part_number */
+
+static int parse_part_string (void **ret_buffer, int *ret_buffer_len,
+               char *output, int output_len)
+{
+       char *buffer = *ret_buffer;
+       int   buffer_len = *ret_buffer_len;
+
+       uint16_t tmp16;
+       size_t header_size = 2 * sizeof (uint16_t);
+
+       uint16_t pkg_length;
+       uint16_t pkg_type;
+
+       if (buffer_len < header_size)
+       {
+               WARNING ("network plugin: parse_part_string: "
+                               "Packet too short: "
+                               "Chunk of at least size %u expected, "
+                               "but buffer has only %i bytes left.",
+                               (unsigned int) header_size, buffer_len);
+               return (-1);
+       }
+
+       memcpy ((void *) &tmp16, buffer, sizeof (tmp16));
+       buffer += sizeof (tmp16);
+       pkg_type = ntohs (tmp16);
+
+       memcpy ((void *) &tmp16, buffer, sizeof (tmp16));
+       buffer += sizeof (tmp16);
+       pkg_length = ntohs (tmp16);
+
+       /* Check that packet fits in the input buffer */
+       if (pkg_length > buffer_len)
+       {
+               WARNING ("network plugin: parse_part_string: "
+                               "Packet too big: "
+                               "Chunk of size %hu received, "
+                               "but buffer has only %i bytes left.",
+                               pkg_length, buffer_len);
+               return (-1);
+       }
+
+       /* Check that pkg_length is in the valid range */
+       if (pkg_length <= header_size)
+       {
+               WARNING ("network plugin: parse_part_string: "
+                               "Packet too short: "
+                               "Header claims this packet is only %hu "
+                               "bytes long.", pkg_length);
+               return (-1);
+       }
+
+       /* Check that the package data fits into the output buffer.
+        * The previous if-statement ensures that:
+        * `pkg_length > header_size' */
+       if ((pkg_length - header_size) > output_len)
+       {
+               WARNING ("network plugin: parse_part_string: "
+                               "Output buffer too small.");
+               return (-1);
+       }
+
+       /* All sanity checks successfull, let's copy the data over */
+       output_len = pkg_length - header_size;
+       memcpy ((void *) output, (void *) buffer, output_len);
+       buffer += output_len;
+
+       /* For some very weird reason '\0' doesn't do the trick on SPARC in
+        * this statement. */
+       if (output[output_len - 1] != 0)
+       {
+               WARNING ("network plugin: parse_part_string: "
+                               "Received string does not end "
+                               "with a NULL-byte.");
+               return (-1);
+       }
+
+       *ret_buffer = buffer;
+       *ret_buffer_len = buffer_len - pkg_length;
+
+       return (0);
+} /* int parse_part_string */
+
+static int parse_packet (void *buffer, int buffer_len)
+{
+       int status;
+
+       value_list_t vl = VALUE_LIST_INIT;
+       char type[DATA_MAX_NAME_LEN];
+       notification_t n;
+
+       DEBUG ("network plugin: parse_packet: buffer = %p; buffer_len = %i;",
+                       buffer, buffer_len);
+
+       memset (&vl, '\0', sizeof (vl));
+       memset (&type, '\0', sizeof (type));
+       memset (&n, '\0', sizeof (n));
+       status = 0;
+
+       while ((status == 0) && (0 < buffer_len)
+                       && ((unsigned int) buffer_len > sizeof (part_header_t)))
+       {
+               uint16_t pkg_length;
+               uint16_t pkg_type;
+
+               memcpy ((void *) &pkg_type,
+                               (void *) buffer,
+                               sizeof (pkg_type));
+               memcpy ((void *) &pkg_length,
+                               (void *) (buffer + sizeof (pkg_type)),
+                               sizeof (pkg_length));
+
+               pkg_length = ntohs (pkg_length);
+               pkg_type = ntohs (pkg_type);
+
+               if (pkg_length > buffer_len)
+                       break;
+               /* Ensure that this loop terminates eventually */
+               if (pkg_length < (2 * sizeof (uint16_t)))
+                       break;
+
+               if (pkg_type == TYPE_VALUES)
+               {
+                       status = parse_part_values (&buffer, &buffer_len,
+                                       &vl.values, &vl.values_len);
+
+                       if (status != 0)
+                               break;
+
+                       if ((vl.time > 0)
+                                       && (strlen (vl.host) > 0)
+                                       && (strlen (vl.plugin) > 0)
+                                       && (strlen (type) > 0)
+                                       && (cache_check (type, &vl) == 0))
+                       {
+                               plugin_dispatch_values (type, &vl);
+                       }
+                       else
+                       {
+                               DEBUG ("network plugin: parse_packet:"
+                                               " NOT dispatching values");
+                       }
+
+                       sfree (vl.values);
+               }
+               else if (pkg_type == TYPE_TIME)
+               {
+                       uint64_t tmp = 0;
+                       status = parse_part_number (&buffer, &buffer_len,
+                                       &tmp);
+                       if (status == 0)
+                       {
+                               vl.time = (time_t) tmp;
+                               n.time = (time_t) tmp;
+                       }
+               }
+               else if (pkg_type == TYPE_INTERVAL)
+               {
+                       uint64_t tmp = 0;
+                       status = parse_part_number (&buffer, &buffer_len,
+                                       &tmp);
+                       if (status == 0)
+                               vl.interval = (int) tmp;
+               }
+               else if (pkg_type == TYPE_HOST)
+               {
+                       status = parse_part_string (&buffer, &buffer_len,
+                                       vl.host, sizeof (vl.host));
+                       if (status == 0)
+                               sstrncpy (n.host, vl.host, sizeof (n.host));
+               }
+               else if (pkg_type == TYPE_PLUGIN)
+               {
+                       status = parse_part_string (&buffer, &buffer_len,
+                                       vl.plugin, sizeof (vl.plugin));
+                       if (status == 0)
+                               sstrncpy (n.plugin, vl.plugin,
+                                               sizeof (n.plugin));
+               }
+               else if (pkg_type == TYPE_PLUGIN_INSTANCE)
+               {
+                       status = parse_part_string (&buffer, &buffer_len,
+                                       vl.plugin_instance,
+                                       sizeof (vl.plugin_instance));
+                       if (status == 0)
+                               sstrncpy (n.plugin_instance,
+                                               vl.plugin_instance,
+                                               sizeof (n.plugin_instance));
+               }
+               else if (pkg_type == TYPE_TYPE)
+               {
+                       status = parse_part_string (&buffer, &buffer_len,
+                                       type, sizeof (type));
+                       if (status == 0)
+                               sstrncpy (n.type, type, sizeof (n.type));
+               }
+               else if (pkg_type == TYPE_TYPE_INSTANCE)
+               {
+                       status = parse_part_string (&buffer, &buffer_len,
+                                       vl.type_instance,
+                                       sizeof (vl.type_instance));
+                       if (status == 0)
+                               sstrncpy (n.type_instance, vl.type_instance,
+                                               sizeof (n.type_instance));
+               }
+               else if (pkg_type == TYPE_MESSAGE)
+               {
+                       status = parse_part_string (&buffer, &buffer_len,
+                                       n.message, sizeof (n.message));
+
+                       if (status != 0)
+                       {
+                               /* do nothing */
+                       }
+                       else if ((n.severity != NOTIF_FAILURE)
+                                       && (n.severity != NOTIF_WARNING)
+                                       && (n.severity != NOTIF_OKAY))
+                       {
+                               INFO ("network plugin: "
+                                               "Ignoring notification with "
+                                               "unknown severity %i.",
+                                               n.severity);
+                       }
+                       else if (n.time <= 0)
+                       {
+                               INFO ("network plugin: "
+                                               "Ignoring notification with "
+                                               "time == 0.");
+                       }
+                       else if (strlen (n.message) <= 0)
+                       {
+                               INFO ("network plugin: "
+                                               "Ignoring notification with "
+                                               "an empty message.");
+                       }
+                       else
+                       {
+                               plugin_dispatch_notification (&n);
+                       }
+               }
+               else if (pkg_type == TYPE_SEVERITY)
+               {
+                       uint64_t tmp = 0;
+                       status = parse_part_number (&buffer, &buffer_len,
+                                       &tmp);
+                       if (status == 0)
+                               n.severity = (int) tmp;
+               }
+               else
+               {
+                       DEBUG ("network plugin: parse_packet: Unknown part"
+                                       " type: 0x%04hx", pkg_type);
+                       buffer = ((char *) buffer) + pkg_length;
+               }
+       } /* while (buffer_len > sizeof (part_header_t)) */
+
+       return (status);
+} /* int parse_packet */
+
+static void free_sockent (sockent_t *se)
+{
+       sockent_t *next;
+       while (se != NULL)
+       {
+               next = se->next;
+               free (se->addr);
+               free (se);
+               se = next;
+       }
+} /* void free_sockent */
+
+/*
+ * int network_set_ttl
+ *
+ * Set the `IP_MULTICAST_TTL', `IP_TTL', `IPV6_MULTICAST_HOPS' or
+ * `IPV6_UNICAST_HOPS', depending on which option is applicable.
+ *
+ * The `struct addrinfo' is used to destinguish between unicast and multicast
+ * sockets.
+ */
+static int network_set_ttl (const sockent_t *se, const struct addrinfo *ai)
+{
+       if ((network_config_ttl < 1) || (network_config_ttl > 255))
+               return (-1);
+
+       DEBUG ("ttl = %i", network_config_ttl);
 
        if (ai->ai_family == AF_INET)
        {
@@ -95,9 +888,12 @@ static int network_set_ttl (const sockent_t *se, const struct addrinfo *ai)
                        optname = IP_TTL;
 
                if (setsockopt (se->fd, IPPROTO_IP, optname,
-                                       &ttl_int, sizeof (ttl_int)) == -1)
+                                       &network_config_ttl,
+                                       sizeof (network_config_ttl)) == -1)
                {
-                       syslog (LOG_ERR, "setsockopt: %s", strerror (errno));
+                       char errbuf[1024];
+                       ERROR ("setsockopt: %s",
+                                       sstrerror (errno, errbuf, sizeof (errbuf)));
                        return (-1);
                }
        }
@@ -113,25 +909,41 @@ static int network_set_ttl (const sockent_t *se, const struct addrinfo *ai)
                        optname = IPV6_UNICAST_HOPS;
 
                if (setsockopt (se->fd, IPPROTO_IPV6, optname,
-                                       &ttl_int, sizeof (ttl_int)) == -1)
+                                       &network_config_ttl,
+                                       sizeof (network_config_ttl)) == -1)
                {
-                       syslog (LOG_ERR, "setsockopt: %s", strerror (errno));
+                       char errbuf[1024];
+                       ERROR ("setsockopt: %s",
+                                       sstrerror (errno, errbuf,
+                                               sizeof (errbuf)));
                        return (-1);
                }
        }
 
        return (0);
-}
+} /* int network_set_ttl */
 
 static int network_bind_socket (const sockent_t *se, const struct addrinfo *ai)
 {
-       int loop = 1;
+       int loop = 0;
+       int yes  = 1;
+
+       /* allow multiple sockets to use the same PORT number */
+       if (setsockopt(se->fd, SOL_SOCKET, SO_REUSEADDR,
+                               &yes, sizeof(yes)) == -1) {
+                char errbuf[1024];
+                ERROR ("setsockopt: %s", 
+                                sstrerror (errno, errbuf, sizeof (errbuf)));
+               return (-1);
+       }
 
-       DBG ("fd = %i; calling `bind'", se->fd);
+       DEBUG ("fd = %i; calling `bind'", se->fd);
 
        if (bind (se->fd, ai->ai_addr, ai->ai_addrlen) == -1)
        {
-               syslog (LOG_ERR, "bind: %s", strerror (errno));
+               char errbuf[1024];
+               ERROR ("bind: %s",
+                               sstrerror (errno, errbuf, sizeof (errbuf)));
                return (-1);
        }
 
@@ -142,7 +954,7 @@ static int network_bind_socket (const sockent_t *se, const struct addrinfo *ai)
                {
                        struct ip_mreq mreq;
 
-                       DBG ("fd = %i; IPv4 multicast address found", se->fd);
+                       DEBUG ("fd = %i; IPv4 multicast address found", se->fd);
 
                        mreq.imr_multiaddr.s_addr = addr->sin_addr.s_addr;
                        mreq.imr_interface.s_addr = htonl (INADDR_ANY);
@@ -150,14 +962,20 @@ static int network_bind_socket (const sockent_t *se, const struct addrinfo *ai)
                        if (setsockopt (se->fd, IPPROTO_IP, IP_MULTICAST_LOOP,
                                                &loop, sizeof (loop)) == -1)
                        {
-                               syslog (LOG_ERR, "setsockopt: %s", strerror (errno));
+                               char errbuf[1024];
+                               ERROR ("setsockopt: %s",
+                                               sstrerror (errno, errbuf,
+                                                       sizeof (errbuf)));
                                return (-1);
                        }
 
                        if (setsockopt (se->fd, IPPROTO_IP, IP_ADD_MEMBERSHIP,
                                                &mreq, sizeof (mreq)) == -1)
                        {
-                               syslog (LOG_ERR, "setsockopt: %s", strerror (errno));
+                               char errbuf[1024];
+                               ERROR ("setsockopt: %s",
+                                               sstrerror (errno, errbuf,
+                                                       sizeof (errbuf)));
                                return (-1);
                        }
                }
@@ -170,7 +988,7 @@ static int network_bind_socket (const sockent_t *se, const struct addrinfo *ai)
                {
                        struct ipv6_mreq mreq;
 
-                       DBG ("fd = %i; IPv6 multicast address found", se->fd);
+                       DEBUG ("fd = %i; IPv6 multicast address found", se->fd);
 
                        memcpy (&mreq.ipv6mr_multiaddr,
                                        &addr->sin6_addr,
@@ -190,44 +1008,40 @@ static int network_bind_socket (const sockent_t *se, const struct addrinfo *ai)
                        if (setsockopt (se->fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP,
                                                &loop, sizeof (loop)) == -1)
                        {
-                               syslog (LOG_ERR, "setsockopt: %s", strerror (errno));
+                               char errbuf[1024];
+                               ERROR ("setsockopt: %s",
+                                               sstrerror (errno, errbuf,
+                                                       sizeof (errbuf)));
                                return (-1);
                        }
 
                        if (setsockopt (se->fd, IPPROTO_IPV6, IPV6_ADD_MEMBERSHIP,
                                                &mreq, sizeof (mreq)) == -1)
                        {
-                               syslog (LOG_ERR, "setsockopt: %s", strerror (errno));
+                               char errbuf[1024];
+                               ERROR ("setsockopt: %s",
+                                               sstrerror (errno, errbuf,
+                                                       sizeof (errbuf)));
                                return (-1);
                        }
                }
        }
 
        return (0);
-}
+} /* int network_bind_socket */
 
-int network_create_socket (const char *node, const char *service)
+static sockent_t *network_create_socket (const char *node,
+               const char *service,
+               int listen)
 {
-       sockent_t *socklist_tail;
-
        struct addrinfo  ai_hints;
        struct addrinfo *ai_list, *ai_ptr;
        int              ai_return;
 
-       int num_added = 0;
+       sockent_t *se_head = NULL;
+       sockent_t *se_tail = NULL;
 
-       DBG ("node = %s, service = %s", node, service);
-
-       if (operating_mode == MODE_LOCAL || operating_mode == MODE_LOG)
-       {
-               syslog (LOG_WARNING, "network_create_socket: There is no point opening a socket when you are in mode `%s'.",
-                               operating_mode == MODE_LOCAL ? "Local" : "Log");
-               return (-1);
-       }
-
-       socklist_tail = socklist_head;
-       while ((socklist_tail != NULL) && (socklist_tail->next != NULL))
-               socklist_tail = socklist_tail->next;
+       DEBUG ("node = %s, service = %s", node, service);
 
        memset (&ai_hints, '\0', sizeof (ai_hints));
        ai_hints.ai_flags    = 0;
@@ -237,17 +1051,21 @@ int network_create_socket (const char *node, const char *service)
 #ifdef AI_ADDRCONFIG
        ai_hints.ai_flags |= AI_ADDRCONFIG;
 #endif
-       ai_hints.ai_family   = PF_UNSPEC;
+       ai_hints.ai_family   = AF_UNSPEC;
        ai_hints.ai_socktype = SOCK_DGRAM;
        ai_hints.ai_protocol = IPPROTO_UDP;
 
-       if ((ai_return = getaddrinfo (node, service, &ai_hints, &ai_list)) != 0)
+       ai_return = getaddrinfo (node, service, &ai_hints, &ai_list);
+       if (ai_return != 0)
        {
-               syslog (LOG_ERR, "getaddrinfo (%s, %s): %s",
-                               node == NULL ? "(null)" : node,
-                               service == NULL ? "(null)" : service,
-                               ai_return == EAI_SYSTEM ? strerror (errno) : gai_strerror (ai_return));
-               return (-1);
+               char errbuf[1024];
+               ERROR ("getaddrinfo (%s, %s): %s",
+                               (node == NULL) ? "(null)" : node,
+                               (service == NULL) ? "(null)" : service,
+                               (ai_return == EAI_SYSTEM)
+                               ? sstrerror (errno, errbuf, sizeof (errbuf))
+                               : gai_strerror (ai_return));
+               return (NULL);
        }
 
        for (ai_ptr = ai_list; ai_ptr != NULL; ai_ptr = ai_ptr->ai_next)
@@ -256,13 +1074,19 @@ int network_create_socket (const char *node, const char *service)
 
                if ((se = (sockent_t *) malloc (sizeof (sockent_t))) == NULL)
                {
-                       syslog (LOG_EMERG, "malloc: %s", strerror (errno));
+                       char errbuf[1024];
+                       ERROR ("malloc: %s",
+                                       sstrerror (errno, errbuf,
+                                               sizeof (errbuf)));
                        continue;
                }
 
                if ((se->addr = (struct sockaddr_storage *) malloc (sizeof (struct sockaddr_storage))) == NULL)
                {
-                       syslog (LOG_EMERG, "malloc: %s", strerror (errno));
+                       char errbuf[1024];
+                       ERROR ("malloc: %s",
+                                       sstrerror (errno, errbuf,
+                                               sizeof (errbuf)));
                        free (se);
                        continue;
                }
@@ -272,19 +1096,23 @@ int network_create_socket (const char *node, const char *service)
                memcpy (se->addr, ai_ptr->ai_addr, ai_ptr->ai_addrlen);
                se->addrlen = ai_ptr->ai_addrlen;
 
-               se->mode = operating_mode;
-               se->fd   = socket (ai_ptr->ai_family, ai_ptr->ai_socktype, ai_ptr->ai_protocol);
+               se->fd   = socket (ai_ptr->ai_family,
+                               ai_ptr->ai_socktype,
+                               ai_ptr->ai_protocol);
                se->next = NULL;
 
                if (se->fd == -1)
                {
-                       syslog (LOG_ERR, "socket: %s", strerror (errno));
+                       char errbuf[1024];
+                       ERROR ("socket: %s",
+                                       sstrerror (errno, errbuf,
+                                               sizeof (errbuf)));
                        free (se->addr);
                        free (se);
                        continue;
                }
 
-               if (operating_mode == MODE_SERVER)
+               if (listen != 0)
                {
                        if (network_bind_socket (se, ai_ptr) != 0)
                        {
@@ -294,260 +1122,654 @@ int network_create_socket (const char *node, const char *service)
                                continue;
                        }
                }
-               else if (operating_mode == MODE_CLIENT)
+               else /* listen == 0 */
                {
                        network_set_ttl (se, ai_ptr);
                }
 
-               if (socklist_tail == NULL)
+               if (se_tail == NULL)
                {
-                       socklist_head = se;
-                       socklist_tail = se;
+                       se_head = se;
+                       se_tail = se;
                }
                else
                {
-                       socklist_tail->next = se;
-                       socklist_tail = se;
+                       se_tail->next = se;
+                       se_tail = se;
                }
 
-               num_added++;
-
                /* We don't open more than one write-socket per node/service pair.. */
-               if (operating_mode == MODE_CLIENT)
+               if (listen == 0)
                        break;
        }
 
        freeaddrinfo (ai_list);
 
-       return (num_added);
-}
+       return (se_head);
+} /* sockent_t *network_create_socket */
 
-static int network_connect_default (void)
+static sockent_t *network_create_default_socket (int listen)
 {
-       int ret;
+       sockent_t *se_ptr  = NULL;
+       sockent_t *se_head = NULL;
+       sockent_t *se_tail = NULL;
 
-       if (socklist_head != NULL)
-               return (0);
+       se_ptr = network_create_socket (NET_DEFAULT_V6_ADDR,
+                       NET_DEFAULT_PORT, listen);
 
-       DBG ("socklist_head is NULL");
+       /* Don't send to the same machine in IPv6 and IPv4 if both are available. */
+       if ((listen == 0) && (se_ptr != NULL))
+               return (se_ptr);
 
-       ret = 0;
+       if (se_ptr != NULL)
+       {
+               se_head = se_ptr;
+               se_tail = se_ptr;
+               while (se_tail->next != NULL)
+                       se_tail = se_tail->next;
+       }
 
-       if (network_create_socket (NET_DEFAULT_V6_ADDR, NET_DEFAULT_PORT) > 0)
-               ret++;
+       se_ptr = network_create_socket (NET_DEFAULT_V4_ADDR, NET_DEFAULT_PORT, listen);
 
-       /* Don't use IPv4 and IPv6 in parallel by default.. */
-       if ((operating_mode == MODE_CLIENT) && (ret != 0))
-               return (ret);
+       if (se_tail == NULL)
+               return (se_ptr);
 
-       if (network_create_socket (NET_DEFAULT_V4_ADDR, NET_DEFAULT_PORT) > 0)
-               ret++;
+       se_tail->next = se_ptr;
+       return (se_head);
+} /* sockent_t *network_create_default_socket */
 
-       if (ret == 0)
-               ret = -1;
+static int network_add_listen_socket (const char *node, const char *service)
+{
+       sockent_t *se;
+       sockent_t *se_ptr;
+       int se_num = 0;
 
-       return (ret);
-}
+       if (service == NULL)
+               service = NET_DEFAULT_PORT;
 
-static int network_get_listen_socket (void)
-{
-       int fd;
-       int max_fd;
-       int status;
+       if (node == NULL)
+               se = network_create_default_socket (1 /* listen == true */);
+       else
+               se = network_create_socket (node, service, 1 /* listen == true */);
 
-       fd_set readfds;
-       sockent_t *se;
+       if (se == NULL)
+               return (-1);
+
+       for (se_ptr = se; se_ptr != NULL; se_ptr = se_ptr->next)
+               se_num++;
 
-       if (socklist_head == NULL)
-               network_connect_default ();
+       listen_sockets = (struct pollfd *) realloc (listen_sockets,
+                       (listen_sockets_num + se_num)
+                       * sizeof (struct pollfd));
 
-       FD_ZERO (&readfds);
-       max_fd = -1;
-       for (se = socklist_head; se != NULL; se = se->next)
+       for (se_ptr = se; se_ptr != NULL; se_ptr = se_ptr->next)
        {
-               if (se->mode != operating_mode)
-                       continue;
+               listen_sockets[listen_sockets_num].fd = se_ptr->fd;
+               listen_sockets[listen_sockets_num].events = POLLIN | POLLPRI;
+               listen_sockets[listen_sockets_num].revents = 0;
+               listen_sockets_num++;
+       } /* for (se) */
 
-               FD_SET (se->fd, &readfds);
-               if (se->fd >= max_fd)
-                       max_fd = se->fd + 1;
-       }
+       free_sockent (se);
+       return (0);
+} /* int network_add_listen_socket */
 
-       if (max_fd == -1)
-       {
-               syslog (LOG_WARNING, "No listen sockets found!");
+static int network_add_sending_socket (const char *node, const char *service)
+{
+       sockent_t *se;
+       sockent_t *se_ptr;
+
+       if (service == NULL)
+               service = NET_DEFAULT_PORT;
+
+       if (node == NULL)
+               se = network_create_default_socket (0 /* listen == false */);
+       else
+               se = network_create_socket (node, service, 0 /* listen == false */);
+
+       if (se == NULL)
                return (-1);
+
+       if (sending_sockets == NULL)
+       {
+               sending_sockets = se;
+               return (0);
        }
 
-       status = select (max_fd, &readfds, NULL, NULL, NULL);
+       for (se_ptr = sending_sockets; se_ptr->next != NULL; se_ptr = se_ptr->next)
+               /* seek end */;
+
+       se_ptr->next = se;
+       return (0);
+} /* int network_get_listen_socket */
+
+static void *dispatch_thread (void *arg)
+{
+  while (42)
+  {
+    receive_list_entry_t *ent;
+
+    /* Lock and wait for more data to come in */
+    pthread_mutex_lock (&receive_list_lock);
+    while ((listen_loop == 0)
+       && (receive_list_head == NULL))
+      pthread_cond_wait (&receive_list_cond, &receive_list_lock);
+
+    /* Remove the head entry and unlock */
+    ent = receive_list_head;
+    if (ent != NULL)
+      receive_list_head = ent->next;
+    pthread_mutex_unlock (&receive_list_lock);
+
+    /* Check whether we are supposed to exit. We do NOT check `listen_loop'
+     * because we dispatch all missing packets before shutting down. */
+    if (ent == NULL)
+      break;
+
+    parse_packet (ent->data, ent->data_len);
+
+    sfree (ent);
+  } /* while (42) */
 
-       if (status == -1)
+  return (NULL);
+} /* void *receive_thread */
+
+static int network_receive (void)
+{
+       char buffer[BUFF_SIZE];
+       int  buffer_len;
+
+       int i;
+       int status;
+
+       if (listen_sockets_num == 0)
+               network_add_listen_socket (NULL, NULL);
+
+       if (listen_sockets_num == 0)
        {
-               if (errno != EINTR)
-                       syslog (LOG_ERR, "select: %s", strerror (errno));
+               ERROR ("network: Failed to open a listening socket.");
                return (-1);
        }
 
-       fd = -1;
-       for (se = socklist_head; se != NULL; se = se->next)
+       while (listen_loop == 0)
        {
-               if (se->mode != operating_mode)
-                       continue;
+               status = poll (listen_sockets, listen_sockets_num, -1);
 
-               if (FD_ISSET (se->fd, &readfds))
+               if (status <= 0)
                {
-                       fd = se->fd;
-                       break;
+                       char errbuf[1024];
+                       if (errno == EINTR)
+                               continue;
+                       ERROR ("poll failed: %s",
+                                       sstrerror (errno, errbuf, sizeof (errbuf)));
+                       return (-1);
                }
-       }
 
-       if (fd == -1)
-               syslog (LOG_WARNING, "No socket ready..?");
+               for (i = 0; (i < listen_sockets_num) && (status > 0); i++)
+               {
+                       receive_list_entry_t *ent;
+
+                       if ((listen_sockets[i].revents & (POLLIN | POLLPRI)) == 0)
+                               continue;
+                       status--;
+
+                       buffer_len = recv (listen_sockets[i].fd,
+                                       buffer, sizeof (buffer),
+                                       0 /* no flags */);
+                       if (buffer_len < 0)
+                       {
+                               char errbuf[1024];
+                               ERROR ("recv failed: %s",
+                                               sstrerror (errno, errbuf,
+                                                       sizeof (errbuf)));
+                               return (-1);
+                       }
+
+                       ent = malloc (sizeof (receive_list_entry_t));
+                       if (ent == NULL)
+                       {
+                               ERROR ("network plugin: malloc failed.");
+                               return (-1);
+                       }
+                       memset (ent, '\0', sizeof (receive_list_entry_t));
+
+                       /* Hopefully this be optimized out by the compiler. It
+                        * might help prevent stupid bugs in the future though.
+                        */
+                       assert (sizeof (ent->data) == sizeof (buffer));
+
+                       memcpy (ent->data, buffer, buffer_len);
+                       ent->data_len = buffer_len;
+
+                       pthread_mutex_lock (&receive_list_lock);
+                       if (receive_list_head == NULL)
+                       {
+                               receive_list_head = ent;
+                               receive_list_tail = ent;
+                       }
+                       else
+                       {
+                               receive_list_tail->next = ent;
+                               receive_list_tail = ent;
+                       }
+                       pthread_cond_signal (&receive_list_cond);
+                       pthread_mutex_unlock (&receive_list_lock);
+               } /* for (listen_sockets) */
+       } /* while (listen_loop == 0) */
 
-       DBG ("fd = %i", fd);
-       return (fd);
+       return (0);
 }
 
-int network_receive (char **host, char **type, char **inst, char **value)
+static void *receive_thread (void *arg)
 {
-       int fd;
-       char buffer[BUFF_SIZE];
+       return (network_receive () ? (void *) 1 : (void *) 0);
+} /* void *receive_thread */
 
-       struct sockaddr_storage addr;
-       socklen_t               addrlen;
+static void network_send_buffer (const char *buffer, int buffer_len)
+{
+       sockent_t *se;
        int status;
 
-       char *fields[4];
+       DEBUG ("network plugin: network_send_buffer: buffer_len = %i", buffer_len);
 
-       assert (operating_mode == MODE_SERVER);
+       for (se = sending_sockets; se != NULL; se = se->next)
+       {
+               while (42)
+               {
+                       status = sendto (se->fd, buffer, buffer_len, 0 /* no flags */,
+                                       (struct sockaddr *) se->addr, se->addrlen);
+                       if (status < 0)
+                       {
+                               char errbuf[1024];
+                               if (errno == EINTR)
+                                       continue;
+                               ERROR ("network plugin: sendto failed: %s",
+                                               sstrerror (errno, errbuf,
+                                                       sizeof (errbuf)));
+                               break;
+                       }
 
-       *host  = NULL;
-       *type  = NULL;
-       *inst  = NULL;
-       *value = NULL;
+                       break;
+               } /* while (42) */
+       } /* for (sending_sockets) */
+} /* void network_send_buffer */
 
-       if ((fd = network_get_listen_socket ()) < 0)
-               return (-1);
+static int add_to_buffer (char *buffer, int buffer_size,
+               value_list_t *vl_def, char *type_def,
+               const data_set_t *ds, const value_list_t *vl)
+{
+       char *buffer_orig = buffer;
 
-       addrlen = sizeof (addr);
-       if (recvfrom (fd, buffer, BUFF_SIZE, 0, (struct sockaddr *) &addr, &addrlen) == -1)
+       if (strcmp (vl_def->host, vl->host) != 0)
        {
-               syslog (LOG_ERR, "recvfrom: %s", strerror (errno));
-               return (-1);
+               if (write_part_string (&buffer, &buffer_size, TYPE_HOST,
+                                       vl->host, strlen (vl->host)) != 0)
+                       return (-1);
+               sstrncpy (vl_def->host, vl->host, sizeof (vl_def->host));
        }
 
-       if ((*host = (char *) malloc (BUFF_SIZE)) == NULL)
+       if (vl_def->time != vl->time)
        {
-               syslog (LOG_EMERG, "malloc: %s", strerror (errno));
-               return (-1);
+               if (write_part_number (&buffer, &buffer_size, TYPE_TIME,
+                                       (uint64_t) vl->time))
+                       return (-1);
+               vl_def->time = vl->time;
        }
 
-       status = getnameinfo ((struct sockaddr *) &addr, addrlen,
-                       *host, BUFF_SIZE, NULL, 0, 0);
-       if (status != 0)
+       if (vl_def->interval != vl->interval)
        {
-               free (*host); *host = NULL;
-               syslog (LOG_ERR, "getnameinfo: %s",
-                               status == EAI_SYSTEM ? strerror (errno) : gai_strerror (status));
-               return (-1);
+               if (write_part_number (&buffer, &buffer_size, TYPE_INTERVAL,
+                                       (uint64_t) vl->interval))
+                       return (-1);
+               vl_def->interval = vl->interval;
        }
 
-       if (strsplit (buffer, fields, 4) != 3)
+       if (strcmp (vl_def->plugin, vl->plugin) != 0)
        {
-               syslog (LOG_WARNING, "Invalid message from `%s'", *host);
-               free (*host); *host = NULL;
-               return (1);
+               if (write_part_string (&buffer, &buffer_size, TYPE_PLUGIN,
+                                       vl->plugin, strlen (vl->plugin)) != 0)
+                       return (-1);
+               sstrncpy (vl_def->plugin, vl->plugin, sizeof (vl_def->plugin));
        }
 
-       if ((*type = strdup (fields[0])) == NULL)
+       if (strcmp (vl_def->plugin_instance, vl->plugin_instance) != 0)
        {
-               syslog (LOG_EMERG, "strdup: %s", strerror (errno));
-               free (*host); *host = NULL;
-               return (-1);
+               if (write_part_string (&buffer, &buffer_size, TYPE_PLUGIN_INSTANCE,
+                                       vl->plugin_instance,
+                                       strlen (vl->plugin_instance)) != 0)
+                       return (-1);
+               sstrncpy (vl_def->plugin_instance, vl->plugin_instance, sizeof (vl_def->plugin_instance));
        }
 
-       if ((*inst = strdup (fields[1])) == NULL)
+       if (strcmp (type_def, ds->type) != 0)
        {
-               syslog (LOG_EMERG, "strdup: %s", strerror (errno));
-               free (*host); *host = NULL;
-               free (*type); *type = NULL;
-               return (-1);
+               if (write_part_string (&buffer, &buffer_size, TYPE_TYPE,
+                                       ds->type, strlen (ds->type)) != 0)
+                       return (-1);
+               sstrncpy (type_def, ds->type, sizeof (type_def));
        }
 
-       if ((*value = strdup (fields[2])) == NULL)
+       if (strcmp (vl_def->type_instance, vl->type_instance) != 0)
        {
-               syslog (LOG_EMERG, "strdup: %s", strerror (errno));
-               free (*host); *host = NULL;
-               free (*type); *type = NULL;
-               free (*inst); *inst = NULL;
-               return (-1);
+               if (write_part_string (&buffer, &buffer_size, TYPE_TYPE_INSTANCE,
+                                       vl->type_instance,
+                                       strlen (vl->type_instance)) != 0)
+                       return (-1);
+               sstrncpy (vl_def->type_instance, vl->type_instance, sizeof (vl_def->type_instance));
        }
+       
+       if (write_part_values (&buffer, &buffer_size, ds, vl) != 0)
+               return (-1);
 
-       DBG ("host = %s, type = %s, inst = %s, value = %s",
-                       *host, *type, *inst, *value);
+       return (buffer - buffer_orig);
+} /* int add_to_buffer */
 
-       return (0);
+static void flush_buffer (void)
+{
+       DEBUG ("network plugin: flush_buffer: send_buffer_fill = %i",
+                       send_buffer_fill);
+
+       network_send_buffer (send_buffer, send_buffer_fill);
+       send_buffer_ptr  = send_buffer;
+       send_buffer_fill = 0;
+       memset (&send_buffer_vl, '\0', sizeof (send_buffer_vl));
+       memset (send_buffer_type, '\0', sizeof (send_buffer_type));
 }
 
-int network_send (char *type, char *inst, char *value)
+static int network_write (const data_set_t *ds, const value_list_t *vl)
 {
-       char buf[BUFF_SIZE];
-       int buflen;
+       int status;
 
-       sockent_t *se;
+       /* If the value is already in the cache, we have received it via the
+        * network. We write it again if forwarding is activated. It's then in
+        * the cache and should we receive it again we will ignore it. */
+       status = cache_check (ds->type, vl);
+       if ((network_config_forward == 0)
+                       && (status != 0))
+               return (0);
 
-       int ret;
-       int status;
+       pthread_mutex_lock (&send_buffer_lock);
 
-       DBG ("type = %s, inst = %s, value = %s", type, inst, value);
+       status = add_to_buffer (send_buffer_ptr,
+                       sizeof (send_buffer) - send_buffer_fill,
+                       &send_buffer_vl, send_buffer_type,
+                       ds, vl);
+       if (status >= 0)
+       {
+               /* status == bytes added to the buffer */
+               send_buffer_fill += status;
+               send_buffer_ptr  += status;
+       }
+       else
+       {
+               flush_buffer ();
 
-       assert (operating_mode == MODE_CLIENT);
+               status = add_to_buffer (send_buffer_ptr,
+                               sizeof (send_buffer) - send_buffer_fill,
+                               &send_buffer_vl, send_buffer_type,
+                               ds, vl);
 
-       buflen = snprintf (buf, BUFF_SIZE, "%s %s %s", type, inst, value);
-       if ((buflen >= BUFF_SIZE) || (buflen < 1))
+               if (status >= 0)
+               {
+                       send_buffer_fill += status;
+                       send_buffer_ptr  += status;
+               }
+       }
+
+       if (status < 0)
+       {
+               ERROR ("network plugin: Unable to append to the "
+                               "buffer for some weird reason");
+       }
+       else if ((sizeof (send_buffer) - send_buffer_fill) < 15)
+       {
+               flush_buffer ();
+       }
+
+       pthread_mutex_unlock (&send_buffer_lock);
+
+       return ((status < 0) ? -1 : 0);
+} /* int network_write */
+
+static int network_config (const char *key, const char *val)
+{
+       char *node;
+       char *service;
+
+       char *fields[3];
+       int   fields_num;
+
+       if ((strcasecmp ("Listen", key) == 0)
+                       || (strcasecmp ("Server", key) == 0))
+       {
+               char *val_cpy = strdup (val);
+               if (val_cpy == NULL)
+                       return (1);
+
+               service = NET_DEFAULT_PORT;
+               fields_num = strsplit (val_cpy, fields, 3);
+               if ((fields_num != 1)
+                               && (fields_num != 2))
+                       return (1);
+               else if (fields_num == 2)
+               {
+                       if ((service = strchr (fields[1], '.')) != NULL)
+                               *service = '\0';
+                       service = fields[1];
+               }
+               node = fields[0];
+
+               if (strcasecmp ("Listen", key) == 0)
+                       network_add_listen_socket (node, service);
+               else
+                       network_add_sending_socket (node, service);
+       }
+       else if (strcasecmp ("TimeToLive", key) == 0)
+       {
+               int tmp = atoi (val);
+               if ((tmp > 0) && (tmp < 256))
+                       network_config_ttl = tmp;
+               else
+                       return (1);
+       }
+       else if (strcasecmp ("Forward", key) == 0)
+       {
+               if ((strcasecmp ("true", val) == 0)
+                               || (strcasecmp ("yes", val) == 0)
+                               || (strcasecmp ("on", val) == 0))
+                       network_config_forward = 1;
+               else
+                       network_config_forward = 0;
+       }
+       else if (strcasecmp ("CacheFlush", key) == 0)
+       {
+               int tmp = atoi (val);
+               if (tmp > 0)
+                       cache_flush_interval = tmp;
+               else return (1);
+       }
+       else
        {
-               syslog (LOG_WARNING, "network_send: snprintf failed..");
                return (-1);
        }
-       buf[buflen] = '\0';
-       buflen++;
+       return (0);
+} /* int network_config */
 
-       if (socklist_head == NULL)
-               network_connect_default ();
+static int network_notification (const notification_t *n)
+{
+  char  buffer[BUFF_SIZE];
+  char *buffer_ptr = buffer;
+  int   buffer_free = sizeof (buffer);
+  int   status;
+
+  memset (buffer, '\0', sizeof (buffer));
+
+
+  status = write_part_number (&buffer_ptr, &buffer_free, TYPE_TIME,
+      (uint64_t) n->time);
+  if (status != 0)
+    return (-1);
+
+  status = write_part_number (&buffer_ptr, &buffer_free, TYPE_SEVERITY,
+      (uint64_t) n->severity);
+  if (status != 0)
+    return (-1);
+
+  if (strlen (n->host) > 0)
+  {
+    status = write_part_string (&buffer_ptr, &buffer_free, TYPE_HOST,
+       n->host, strlen (n->host));
+    if (status != 0)
+      return (-1);
+  }
+
+  if (strlen (n->plugin) > 0)
+  {
+    status = write_part_string (&buffer_ptr, &buffer_free, TYPE_PLUGIN,
+       n->plugin, strlen (n->plugin));
+    if (status != 0)
+      return (-1);
+  }
+
+  if (strlen (n->plugin_instance) > 0)
+  {
+    status = write_part_string (&buffer_ptr, &buffer_free,
+       TYPE_PLUGIN_INSTANCE,
+       n->plugin_instance, strlen (n->plugin_instance));
+    if (status != 0)
+      return (-1);
+  }
+
+  if (strlen (n->type) > 0)
+  {
+    status = write_part_string (&buffer_ptr, &buffer_free, TYPE_TYPE,
+       n->type, strlen (n->type));
+    if (status != 0)
+      return (-1);
+  }
+
+  if (strlen (n->type_instance) > 0)
+  {
+    status = write_part_string (&buffer_ptr, &buffer_free, TYPE_TYPE_INSTANCE,
+       n->type_instance, strlen (n->type_instance));
+    if (status != 0)
+      return (-1);
+  }
+
+  status = write_part_string (&buffer_ptr, &buffer_free, TYPE_MESSAGE,
+      n->message, strlen (n->message));
+  if (status != 0)
+    return (-1);
+
+  network_send_buffer (buffer, sizeof (buffer) - buffer_free);
+
+  return (0);
+} /* int network_notification */
+
+static int network_shutdown (void)
+{
+       listen_loop++;
 
-       ret = 0;
-       for (se = socklist_head; se != NULL; se = se->next)
+       /* Kill the listening thread */
+       if (receive_thread_id != (pthread_t) 0)
        {
-               if (se->mode != operating_mode)
-                       continue;
+               pthread_kill (receive_thread_id, SIGTERM);
+               pthread_join (receive_thread_id, NULL /* no return value */);
+               receive_thread_id = (pthread_t) 0;
+       }
 
-               while (1)
-               {
-                       status = sendto (se->fd, buf, buflen, 0,
-                                       (struct sockaddr *) se->addr, se->addrlen);
+       /* Shutdown the dispatching thread */
+       if (dispatch_thread_id != (pthread_t) 0)
+               pthread_cond_broadcast (&receive_list_cond);
 
-                       if (status == -1)
-                       {
-                               if (errno == EINTR)
-                               {
-                                       DBG ("sendto was interrupted");
-                                       continue;
-                               }
-                               else
-                               {
-                                       syslog (LOG_ERR, "sendto: %s", strerror (errno));
-                                       ret = -1;
-                                       break;
-                               }
-                       }
-                       else if (ret >= 0)
-                               ret++;
-                       break;
+       if (send_buffer_fill > 0)
+               flush_buffer ();
+
+       if (cache_tree != NULL)
+       {
+               void *key;
+               void *value;
+
+               while (c_avl_pick (cache_tree, &key, &value) == 0)
+               {
+                       sfree (key);
+                       sfree (value);
                }
+               c_avl_destroy (cache_tree);
+               cache_tree = NULL;
        }
 
-       if (ret == 0)
-               syslog (LOG_WARNING, "Message wasn't sent to anybody..");
+       /* TODO: Close `sending_sockets' */
 
-       return (ret);
-}
+       plugin_unregister_config ("network");
+       plugin_unregister_init ("network");
+       plugin_unregister_write ("network");
+       plugin_unregister_shutdown ("network");
+
+       /* Let the init function do it's move again ;) */
+       cache_flush_last = 0;
+
+       return (0);
+} /* int network_shutdown */
+
+static int network_init (void)
+{
+       /* Check if we were already initialized. If so, just return - there's
+        * nothing more to do (for now, that is). */
+       if (cache_flush_last != 0)
+               return (0);
+
+       plugin_register_shutdown ("network", network_shutdown);
+
+       send_buffer_ptr  = send_buffer;
+       send_buffer_fill = 0;
+       memset (&send_buffer_vl, '\0', sizeof (send_buffer_vl));
+       memset (send_buffer_type, '\0', sizeof (send_buffer_type));
+
+       cache_tree = c_avl_create ((int (*) (const void *, const void *)) strcmp);
+       cache_flush_last = time (NULL);
+
+       /* setup socket(s) and so on */
+       if (sending_sockets != NULL)
+       {
+               plugin_register_write ("network", network_write);
+               plugin_register_notification ("network", network_notification);
+       }
+
+       if ((listen_sockets_num != 0) && (receive_thread_id == 0))
+       {
+               int status;
+
+               status = pthread_create (&dispatch_thread_id,
+                               NULL /* no attributes */,
+                               dispatch_thread,
+                               NULL /* no argument */);
+               if (status != 0)
+               {
+                       char errbuf[1024];
+                       ERROR ("network: pthread_create failed: %s",
+                                       sstrerror (errno, errbuf,
+                                               sizeof (errbuf)));
+               }
+
+               status = pthread_create (&receive_thread_id,
+                               NULL /* no attributes */,
+                               receive_thread,
+                               NULL /* no argument */);
+               if (status != 0)
+               {
+                       char errbuf[1024];
+                       ERROR ("network: pthread_create failed: %s",
+                                       sstrerror (errno, errbuf,
+                                               sizeof (errbuf)));
+               }
+       }
+       return (0);
+} /* int network_init */
+
+void module_register (void)
+{
+       plugin_register_config ("network", network_config,
+                       config_keys, config_keys_num);
+       plugin_register_init   ("network", network_init);
+} /* void module_register */