Merge branch 'collectd-4.2'
[collectd.git] / src / network.c
index 11c9718..c347552 100644 (file)
@@ -1,6 +1,6 @@
 /**
  * collectd - src/network.c
- * Copyright (C) 2005,2006  Florian octo Forster
+ * Copyright (C) 2005-2007  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
@@ -23,7 +23,7 @@
 #include "plugin.h"
 #include "common.h"
 #include "configfile.h"
-#include "utils_debug.h"
+#include "utils_avltree.h"
 
 #include "network.h"
 
@@ -57,7 +57,7 @@
 # endif
 #endif /* !IP_ADD_MEMBERSHIP */
 
-#define BUFF_SIZE 4096
+#define BUFF_SIZE 1024
 
 /*
  * Private data types
@@ -141,14 +141,16 @@ typedef struct part_values_s part_values_t;
  */
 static const char *config_keys[] =
 {
+       "CacheFlush",
        "Listen",
        "Server",
        "TimeToLive",
-       NULL
+       "Forward"
 };
-static int config_keys_num = 3;
+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;
 
@@ -157,9 +159,135 @@ static int listen_sockets_num = 0;
 static pthread_t listen_thread = 0;
 static int listen_loop = 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;
+static int              cache_flush_interval = 1800;
+
 /*
  * Private functions
  */
+static int cache_flush (void)
+{
+       char **keys = NULL;
+       int    keys_num = 0;
+
+       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)
 {
@@ -225,9 +353,6 @@ static int write_part_string (char **ret_buffer, int *ret_buffer_len,
        part_string_t ps;
        int len;
 
-       if (str_len < 1)
-               return (-1);
-
        len = 4 + str_len + 1;
        if (*ret_buffer_len < len)
                return (-1);
@@ -238,7 +363,8 @@ static int write_part_string (char **ret_buffer, int *ret_buffer_len,
 
        ps.head->type = htons ((uint16_t) type);
        ps.head->length = htons ((uint16_t) str_len + 5);
-       memcpy (ps.value, str, str_len);
+       if (str_len > 0)
+               memcpy (ps.value, str, str_len);
        ps.value[str_len] = '\0';
        *ret_buffer = (void *) (ps.value + (str_len + 1));
 
@@ -259,7 +385,8 @@ static int parse_part_values (void **ret_buffer, int *ret_buffer_len,
 
        if (buffer_len < (15))
        {
-               DBG ("packet is too short: buffer_len = %i", buffer_len);
+               DEBUG ("network plugin: packet is too short: buffer_len = %i",
+                               buffer_len);
                return (-1);
        }
 
@@ -274,7 +401,7 @@ static int parse_part_values (void **ret_buffer, int *ret_buffer_len,
 
        if (h_num != ((h_length - 6) / 9))
        {
-               DBG ("`length' and `num of values' don't match");
+               DEBUG ("`length' and `num of values' don't match");
                return (-1);
        }
 
@@ -325,7 +452,8 @@ static int parse_part_string (void **ret_buffer, int *ret_buffer_len,
        uint16_t h_length;
        uint16_t h_type;
 
-       DBG ("ret_buffer = %p; ret_buffer_len = %i; output = %p; output_len = %i;",
+       DEBUG ("network plugin: parse_part_string: ret_buffer = %p;"
+                       " ret_buffer_len = %i; output = %p; output_len = %i;",
                        *ret_buffer, *ret_buffer_len,
                        (void *) output, output_len);
 
@@ -334,11 +462,12 @@ static int parse_part_string (void **ret_buffer, int *ret_buffer_len,
        h_length = ntohs (ps.head->length);
        h_type = ntohs (ps.head->type);
 
-       DBG ("length = %hu; type = %hu;", h_length, h_type);
+       DEBUG ("network plugin: parse_part_string: length = %hu; type = %hu;",
+                       h_length, h_type);
 
        if (buffer_len < h_length)
        {
-               DBG ("packet is too short");
+               DEBUG ("packet is too short");
                return (-1);
        }
        assert ((h_type == TYPE_HOST)
@@ -350,18 +479,18 @@ static int parse_part_string (void **ret_buffer, int *ret_buffer_len,
        ps.value = buffer + 4;
        if (ps.value[h_length - 5] != '\0')
        {
-               DBG ("String does not end with a nullbyte");
+               DEBUG ("String does not end with a nullbyte");
                return (-1);
        }
 
        if (output_len < (h_length - 4))
        {
-               DBG ("output buffer is too small");
+               DEBUG ("output buffer is too small");
                return (-1);
        }
        strcpy (output, ps.value);
 
-       DBG ("output = %s", output);
+       DEBUG ("network plugin: parse_part_string: output = %s", output);
 
        *ret_buffer = (void *) (buffer + h_length);
        *ret_buffer_len = buffer_len - h_length;
@@ -377,7 +506,8 @@ static int parse_packet (void *buffer, int buffer_len)
        value_list_t vl = VALUE_LIST_INIT;
        char type[DATA_MAX_NAME_LEN];
 
-       DBG ("buffer = %p; buffer_len = %i;", buffer, buffer_len);
+       DEBUG ("network plugin: parse_packet: buffer = %p; buffer_len = %i;",
+                       buffer, buffer_len);
 
        memset (&vl, '\0', sizeof (vl));
        memset (&type, '\0', sizeof (type));
@@ -389,67 +519,86 @@ static int parse_packet (void *buffer, int buffer_len)
 
                if (ntohs (header->length) > buffer_len)
                        break;
+               /* Assure that this loop terminates eventually */
+               if (ntohs (header->length) < 4)
+                       break;
 
-               if (header->type == htons (TYPE_VALUES))
+               if (ntohs (header->type) == TYPE_VALUES)
                {
                        status = parse_part_values (&buffer, &buffer_len,
                                        &vl.values, &vl.values_len);
 
                        if (status != 0)
                        {
-                               DBG ("parse_part_values failed.");
+                               DEBUG ("parse_part_values failed.");
                                break;
                        }
 
                        if ((vl.time > 0)
                                        && (strlen (vl.host) > 0)
                                        && (strlen (vl.plugin) > 0)
-                                       && (strlen (type) > 0))
+                                       && (strlen (type) > 0)
+                                       && (cache_check (type, &vl) == 0))
                        {
-                               DBG ("dispatching values");
+                               DEBUG ("network plugin: parse_packet:"
+                                               " dispatching values");
                                plugin_dispatch_values (type, &vl);
                        }
                        else
                        {
-                               DBG ("NOT dispatching values");
+                               DEBUG ("network plugin: parse_packet:"
+                                               " NOT dispatching values");
                        }
                }
-               else if (header->type == ntohs (TYPE_TIME))
+               else if (ntohs (header->type) == TYPE_TIME)
                {
                        uint64_t tmp = 0;
                        status = parse_part_number (&buffer, &buffer_len, &tmp);
                        if (status == 0)
                                vl.time = (time_t) tmp;
                }
-               else if (header->type == ntohs (TYPE_HOST))
+               else if (ntohs (header->type) == TYPE_INTERVAL)
+               {
+                       uint64_t tmp = 0;
+                       status = parse_part_number (&buffer, &buffer_len, &tmp);
+                       if (status == 0)
+                               vl.interval = (int) tmp;
+               }
+               else if (ntohs (header->type) == TYPE_HOST)
                {
                        status = parse_part_string (&buffer, &buffer_len,
                                        vl.host, sizeof (vl.host));
+                       DEBUG ("network plugin: parse_packet: vl.host = %s", vl.host);
                }
-               else if (header->type == ntohs (TYPE_PLUGIN))
+               else if (ntohs (header->type) == TYPE_PLUGIN)
                {
                        status = parse_part_string (&buffer, &buffer_len,
                                        vl.plugin, sizeof (vl.plugin));
+                       DEBUG ("network plugin: parse_packet: vl.plugin = %s", vl.plugin);
                }
-               else if (header->type == ntohs (TYPE_PLUGIN_INSTANCE))
+               else if (ntohs (header->type) == TYPE_PLUGIN_INSTANCE)
                {
                        status = parse_part_string (&buffer, &buffer_len,
                                        vl.plugin_instance, sizeof (vl.plugin_instance));
+                       DEBUG ("network plugin: parse_packet: vl.plugin_instance = %s", vl.plugin_instance);
                }
-               else if (header->type == ntohs (TYPE_TYPE))
+               else if (ntohs (header->type) == TYPE_TYPE)
                {
                        status = parse_part_string (&buffer, &buffer_len,
                                        type, sizeof (type));
+                       DEBUG ("network plugin: parse_packet: type = %s", type);
                }
-               else if (header->type == ntohs (TYPE_TYPE_INSTANCE))
+               else if (ntohs (header->type) == TYPE_TYPE_INSTANCE)
                {
                        status = parse_part_string (&buffer, &buffer_len,
                                        vl.type_instance, sizeof (vl.type_instance));
+                       DEBUG ("network plugin: parse_packet: vl.type_instance = %s", vl.type_instance);
                }
                else
                {
-                       DBG ("Unknown part type: 0x%0hx", header->type);
-                       buffer = ((char *) buffer) + header->length;
+                       DEBUG ("network plugin: parse_packet: Unknown part"
+                                       " type: 0x%0hx", ntohs (header->type));
+                       buffer = ((char *) buffer) + ntohs (header->length);
                }
        } /* while (buffer_len > sizeof (part_header_t)) */
 
@@ -482,7 +631,7 @@ static int network_set_ttl (const sockent_t *se, const struct addrinfo *ai)
        if ((network_config_ttl < 1) || (network_config_ttl > 255))
                return (-1);
 
-       DBG ("ttl = %i", network_config_ttl);
+       DEBUG ("ttl = %i", network_config_ttl);
 
        if (ai->ai_family == AF_INET)
        {
@@ -498,7 +647,9 @@ static int network_set_ttl (const sockent_t *se, const struct addrinfo *ai)
                                        &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);
                }
        }
@@ -517,7 +668,10 @@ static int network_set_ttl (const sockent_t *se, const struct addrinfo *ai)
                                        &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);
                }
        }
@@ -527,13 +681,25 @@ static int network_set_ttl (const sockent_t *se, const struct addrinfo *ai)
 
 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);
        }
 
@@ -544,7 +710,7 @@ 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);
@@ -552,14 +718,20 @@ 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);
                        }
                }
@@ -572,7 +744,7 @@ 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,
@@ -592,14 +764,20 @@ 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);
                        }
                }
@@ -619,7 +797,7 @@ static sockent_t *network_create_socket (const char *node,
        sockent_t *se_head = NULL;
        sockent_t *se_tail = NULL;
 
-       DBG ("node = %s, service = %s", node, service);
+       DEBUG ("node = %s, service = %s", node, service);
 
        memset (&ai_hints, '\0', sizeof (ai_hints));
        ai_hints.ai_flags    = 0;
@@ -636,11 +814,12 @@ static sockent_t *network_create_socket (const char *node,
        ai_return = getaddrinfo (node, service, &ai_hints, &ai_list);
        if (ai_return != 0)
        {
-               syslog (LOG_ERR, "getaddrinfo (%s, %s): %s",
+               char errbuf[1024];
+               ERROR ("getaddrinfo (%s, %s): %s",
                                (node == NULL) ? "(null)" : node,
                                (service == NULL) ? "(null)" : service,
                                (ai_return == EAI_SYSTEM)
-                               ? strerror (errno)
+                               ? sstrerror (errno, errbuf, sizeof (errbuf))
                                : gai_strerror (ai_return));
                return (NULL);
        }
@@ -651,13 +830,19 @@ static sockent_t *network_create_socket (const char *node,
 
                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;
                }
@@ -674,7 +859,10 @@ static sockent_t *network_create_socket (const char *node,
 
                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;
@@ -811,7 +999,7 @@ static int network_add_sending_socket (const char *node, const char *service)
        return (0);
 } /* int network_get_listen_socket */
 
-int network_receive (void)
+static int network_receive (void)
 {
        char buffer[BUFF_SIZE];
        int  buffer_len;
@@ -824,7 +1012,7 @@ int network_receive (void)
 
        if (listen_sockets_num == 0)
        {
-               syslog (LOG_ERR, "network: Failed to open a listening socket.");
+               ERROR ("network: Failed to open a listening socket.");
                return (-1);
        }
 
@@ -834,10 +1022,11 @@ int network_receive (void)
 
                if (status <= 0)
                {
+                       char errbuf[1024];
                        if (errno == EINTR)
                                continue;
-                       syslog (LOG_ERR, "poll failed: %s",
-                                       strerror (errno));
+                       ERROR ("poll failed: %s",
+                                       sstrerror (errno, errbuf, sizeof (errbuf)));
                        return (-1);
                }
 
@@ -852,7 +1041,10 @@ int network_receive (void)
                                        0 /* no flags */);
                        if (buffer_len < 0)
                        {
-                               syslog (LOG_ERR, "recv failed: %s", strerror (errno));
+                               char errbuf[1024];
+                               ERROR ("recv failed: %s",
+                                               sstrerror (errno, errbuf,
+                                                       sizeof (errbuf)));
                                return (-1);
                        }
 
@@ -868,135 +1060,171 @@ static void *receive_thread (void *arg)
        return (network_receive () ? (void *) 1 : (void *) 0);
 } /* void *receive_thread */
 
-#if 0
-int network_send (char *type, char *inst, char *value)
+static void network_send_buffer (const char *buffer, int buffer_len)
 {
-       char buf[BUFF_SIZE];
-       int buflen;
-
        sockent_t *se;
-
-       int ret;
        int status;
 
-       DBG ("type = %s, inst = %s, value = %s", type, inst, value);
-
-       assert (operating_mode == MODE_CLIENT);
+       DEBUG ("network plugin: network_send_buffer: buffer_len = %i", buffer_len);
 
-       buflen = snprintf (buf, BUFF_SIZE, "%s %s %s", type, inst, value);
-       if ((buflen >= BUFF_SIZE) || (buflen < 1))
-       {
-               syslog (LOG_WARNING, "network_send: snprintf failed..");
-               return (-1);
-       }
-       buf[buflen] = '\0';
-       buflen++;
-
-       if (socklist_head == NULL)
-               network_create_default_socket (0 /* listen == false */);
-
-       ret = 0;
-       for (se = socklist_head; se != NULL; se = se->next)
+       for (se = sending_sockets; se != NULL; se = se->next)
        {
-               while (1)
+               while (42)
                {
-                       status = sendto (se->fd, buf, buflen, 0,
+                       status = sendto (se->fd, buffer, buffer_len, 0 /* no flags */,
                                        (struct sockaddr *) se->addr, se->addrlen);
-
-                       if (status == -1)
+                       if (status < 0)
                        {
+                               char errbuf[1024];
                                if (errno == EINTR)
-                               {
-                                       DBG ("sendto was interrupted");
                                        continue;
-                               }
-                               else
-                               {
-                                       syslog (LOG_ERR, "sendto: %s", strerror (errno));
-                                       ret = -1;
-                                       break;
-                               }
+                               ERROR ("network plugin: sendto failed: %s",
+                                               sstrerror (errno, errbuf,
+                                                       sizeof (errbuf)));
+                               break;
                        }
-                       else if (ret >= 0)
-                               ret++;
+
                        break;
-               }
-       }
+               } /* while (42) */
+       } /* for (sending_sockets) */
+} /* void network_send_buffer */
 
-       if (ret == 0)
-               syslog (LOG_WARNING, "Message wasn't sent to anybody..");
+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;
 
-       return (ret);
-} /* int network_send */
-#endif
+       if (strcmp (vl_def->host, vl->host) != 0)
+       {
+               if (write_part_string (&buffer, &buffer_size, TYPE_HOST,
+                                       vl->host, strlen (vl->host)) != 0)
+                       return (-1);
+               strcpy (vl_def->host, vl->host);
+       }
 
-static int network_write (const data_set_t *ds, const value_list_t *vl)
-{
-       char  buf[BUFF_SIZE];
-       char *buf_ptr;
-       int   buf_len;
+       if (vl_def->time != vl->time)
+       {
+               if (write_part_number (&buffer, &buffer_size, TYPE_TIME,
+                                       (uint64_t) vl->time))
+                       return (-1);
+               vl_def->time = vl->time;
+       }
 
-       sockent_t *se;
+       if (vl_def->interval != vl->interval)
+       {
+               if (write_part_number (&buffer, &buffer_size, TYPE_INTERVAL,
+                                       (uint64_t) vl->interval))
+                       return (-1);
+               vl_def->interval = vl->interval;
+       }
 
-       DBG ("time = %u; host = %s; "
-                       "plugin = %s; plugin_instance = %s; "
-                       "type = %s; type_instance = %s;",
-                       (unsigned int) vl->time, vl->host,
-                       vl->plugin, vl->plugin_instance,
-                       ds->type, vl->type_instance);
-
-       buf_len = sizeof (buf);
-       buf_ptr = buf;
-       if (write_part_string (&buf_ptr, &buf_len, TYPE_HOST,
-                               vl->host, strlen (vl->host)) != 0)
-               return (-1);
-       if (write_part_number (&buf_ptr, &buf_len, TYPE_TIME,
-                               (uint64_t) vl->time))
-               return (-1);
-       if (write_part_string (&buf_ptr, &buf_len, TYPE_PLUGIN,
-                               vl->plugin, strlen (vl->plugin)) != 0)
-               return (-1);
-       if (strlen (vl->plugin_instance) > 0)
-               if (write_part_string (&buf_ptr, &buf_len, TYPE_PLUGIN_INSTANCE,
+       if (strcmp (vl_def->plugin, vl->plugin) != 0)
+       {
+               if (write_part_string (&buffer, &buffer_size, TYPE_PLUGIN,
+                                       vl->plugin, strlen (vl->plugin)) != 0)
+                       return (-1);
+               strcpy (vl_def->plugin, vl->plugin);
+       }
+
+       if (strcmp (vl_def->plugin_instance, vl->plugin_instance) != 0)
+       {
+               if (write_part_string (&buffer, &buffer_size, TYPE_PLUGIN_INSTANCE,
                                        vl->plugin_instance,
                                        strlen (vl->plugin_instance)) != 0)
                        return (-1);
-       if (write_part_string (&buf_ptr, &buf_len, TYPE_TYPE,
-                               ds->type, strlen (ds->type)) != 0)
-               return (-1);
-       if (strlen (vl->type_instance) > 0)
-               if (write_part_string (&buf_ptr, &buf_len, TYPE_PLUGIN_INSTANCE,
+               strcpy (vl_def->plugin_instance, vl->plugin_instance);
+       }
+
+       if (strcmp (type_def, ds->type) != 0)
+       {
+               if (write_part_string (&buffer, &buffer_size, TYPE_TYPE,
+                                       ds->type, strlen (ds->type)) != 0)
+                       return (-1);
+               strcpy (type_def, ds->type);
+       }
+
+       if (strcmp (vl_def->type_instance, vl->type_instance) != 0)
+       {
+               if (write_part_string (&buffer, &buffer_size, TYPE_TYPE_INSTANCE,
                                        vl->type_instance,
                                        strlen (vl->type_instance)) != 0)
                        return (-1);
+               strcpy (vl_def->type_instance, vl->type_instance);
+       }
        
-       write_part_values (&buf_ptr, &buf_len, ds, vl);
+       if (write_part_values (&buffer, &buffer_size, ds, vl) != 0)
+               return (-1);
 
-       buf_len = sizeof (buf) - buf_len;
+       return (buffer - buffer_orig);
+} /* int add_to_buffer */
 
-       for (se = sending_sockets; se != NULL; se = se->next)
+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));
+}
+
+static int network_write (const data_set_t *ds, const value_list_t *vl)
+{
+       int status;
+
+       /* 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);
+
+       pthread_mutex_lock (&send_buffer_lock);
+
+       status = add_to_buffer (send_buffer_ptr,
+                       sizeof (send_buffer) - send_buffer_fill,
+                       &send_buffer_vl, send_buffer_type,
+                       ds, vl);
+       if (status >= 0)
        {
-               int status;
+               /* status == bytes added to the buffer */
+               send_buffer_fill += status;
+               send_buffer_ptr  += status;
+       }
+       else
+       {
+               flush_buffer ();
 
-               while (42)
+               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 = sendto (se->fd, buf, buf_len, 0 /* no flags */,
-                                       (struct sockaddr *) se->addr, se->addrlen);
-                       if (status < 0)
-                       {
-                               if (errno == EINTR)
-                                       continue;
-                               syslog (LOG_ERR, "network: sendto failed: %s",
-                                               strerror (errno));
-                               break;
-                       }
+                       send_buffer_fill += status;
+                       send_buffer_ptr  += status;
+               }
+       }
 
-                       break;
-               } /* while (42) */
-       } /* for (sending_sockets) */
+       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 ();
+       }
 
-       return 0;
-}
+       pthread_mutex_unlock (&send_buffer_lock);
+
+       return ((status < 0) ? -1 : 0);
+} /* int network_write */
 
 static int network_config (const char *key, const char *val)
 {
@@ -1019,7 +1247,11 @@ static int network_config (const char *key, const char *val)
                                && (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)
@@ -1035,31 +1267,79 @@ static int network_config (const char *key, const char *val)
                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
        {
                return (-1);
        }
        return (0);
-}
+} /* int network_config */
 
 static int network_shutdown (void)
 {
-       DBG ("Shutting down.");
-
        listen_loop++;
 
-       pthread_kill (listen_thread, SIGTERM);
-       pthread_join (listen_thread, NULL /* no return value */);
+       if (listen_thread != (pthread_t) 0)
+       {
+               pthread_kill (listen_thread, SIGTERM);
+               pthread_join (listen_thread, NULL /* no return value */);
+               listen_thread = (pthread_t) 0;
+       }
+
+       if (send_buffer_fill > 0)
+               flush_buffer ();
 
-       listen_thread = 0;
+       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;
+       }
+
+       /* TODO: Close `sending_sockets' */
+
+       plugin_unregister_config ("network");
+       plugin_unregister_init ("network");
+       plugin_unregister_write ("network");
+       plugin_unregister_shutdown ("network");
 
        return (0);
-}
+} /* int network_shutdown */
 
 static int network_init (void)
 {
        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);
@@ -1072,8 +1352,12 @@ static int network_init (void)
                                receive_thread, NULL /* no argument */);
 
                if (status != 0)
-                       syslog (LOG_ERR, "network: pthread_create failed: %s",
-                                       strerror (errno));
+               {
+                       char errbuf[1024];
+                       ERROR ("network: pthread_create failed: %s",
+                                       sstrerror (errno, errbuf,
+                                               sizeof (errbuf)));
+               }
        }
        return (0);
 } /* int network_init */
@@ -1083,4 +1367,4 @@ void module_register (void)
        plugin_register_config ("network", network_config,
                        config_keys, config_keys_num);
        plugin_register_init   ("network", network_init);
-}
+} /* void module_register */