]> git.meshlink.io Git - meshlink/blobdiff - src/net.c
Rename mesh_mutex to mutex.
[meshlink] / src / net.c
index 718295349738c9473616c4b0caa03ea32eb65b4f..80490efadb785ab59db7cb6e8a43e850008b9131 100644 (file)
--- a/src/net.c
+++ b/src/net.c
@@ -1,7 +1,6 @@
 /*
     net.c -- most of the network code
-    Copyright (C) 1998-2002 Ivo Timmermans <itimmermans@bigfoot.com>,
-                  2000-2002 Guus Sliepen <guus@sliepen.warande.net>
+    Copyright (C) 2014-2017 Guus Sliepen <guus@meshlink.io>
 
     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
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     GNU General Public License for more details.
 
-    You should have received a copy of the GNU General Public License
-    along with this program; if not, write to the Free Software
-    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
-
-    $Id: net.c,v 1.35.4.153 2002/02/11 14:20:21 guus Exp $
+    You should have received a copy of the GNU General Public License along
+    with this program; if not, write to the Free Software Foundation, Inc.,
+    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
 
-#include "config.h"
-
-#include <errno.h>
-#include <fcntl.h>
-#include <netdb.h>
-#include <netinet/in.h>
-#ifdef HAVE_LINUX
- #include <netinet/ip.h>
- #include <netinet/tcp.h>
-#endif
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <signal.h>
-#include <sys/signal.h>
-#include <sys/time.h>
-#include <sys/types.h>
-#include <syslog.h>
-#include <unistd.h>
-#include <sys/ioctl.h>
-/* SunOS really wants sys/socket.h BEFORE net/if.h,
-   and FreeBSD wants these lines below the rest. */
-#include <arpa/inet.h>
-#include <sys/socket.h>
-#include <net/if.h>
-
-#include <openssl/rand.h>
-#include <openssl/evp.h>
-#include <openssl/pem.h>
-#include <openssl/hmac.h>
-
-#ifndef HAVE_RAND_PSEUDO_BYTES
-#define RAND_pseudo_bytes RAND_bytes
-#endif
-
-#include <utils.h>
-#include <xalloc.h>
-#include <avl_tree.h>
-#include <list.h>
+#include "system.h"
 
+#include "utils.h"
 #include "conf.h"
 #include "connection.h"
+#include "graph.h"
+#include "logger.h"
+#include "meshlink_internal.h"
 #include "meta.h"
 #include "net.h"
 #include "netutl.h"
-#include "process.h"
 #include "protocol.h"
-#include "subnet.h"
-#include "graph.h"
-#include "process.h"
-#include "route.h"
-#include "device.h"
-#include "event.h"
+#include "xalloc.h"
 
-#include "system.h"
+#include <assert.h>
+
+#if !defined(min)
+static inline int min(int a, int b) {
+       return a < b ? a : b;
+}
+#endif
+
+static const int default_timeout = 5;
+static const int default_interval = 60;
+
+/*
+  Terminate a connection:
+  - Mark it as inactive
+  - Remove the edge representing this connection
+  - Kill it with fire
+  - Check if we need to retry making an outgoing connection
+*/
+void terminate_connection(meshlink_handle_t *mesh, connection_t *c, bool report) {
+       logger(mesh, MESHLINK_INFO, "Closing connection with %s", c->name);
+
+       c->status.active = false;
 
-int maxtimeout = 900;
-int seconds_till_retry = 5;
+       if(c->node && c->node->connection == c) {
+               c->node->connection = NULL;
+       }
 
-int tcp_socket = -1;
-int udp_socket = -1;
+       if(c->edge) {
+               if(report) {
+                       send_del_edge(mesh, mesh->everyone, c->edge, 0);
+               }
 
-int keylifetime = 0;
-int keyexpires = 0;
+               edge_del(mesh, c->edge);
+               c->edge = NULL;
 
-int do_prune = 0;
-int do_purge = 0;
-int sighup = 0;
-int sigalrm = 0;
+               /* Run MST and SSSP algorithms */
 
-#define MAX_SEQNO 1073741824
+               graph(mesh);
 
-/* VPN packet I/O */
+               /* If the node is not reachable anymore but we remember it had an edge to us, clean it up */
 
-void receive_udppacket(node_t *n, vpn_packet_t *inpkt)
-{
-  vpn_packet_t outpkt;
-  int outlen, outpad;
-  EVP_CIPHER_CTX ctx;
-  char hmac[EVP_MAX_MD_SIZE];
-cp
-
-  if(myself->digest && myself->maclength)
-    {
-      inpkt->len -= myself->maclength;
-      HMAC(myself->digest, myself->key, myself->keylength, (char *)&inpkt->seqno, inpkt->len, hmac, NULL);
-      if(memcmp(hmac, (char *)&inpkt->seqno + inpkt->len, myself->maclength))
-       {
-         syslog(LOG_DEBUG, _("Got unauthenticated packet from %s (%s)"), n->name, n->hostname);
-         return;
+               if(report && c->node && !c->node->status.reachable) {
+                       edge_t *e;
+                       e = lookup_edge(c->node, mesh->self);
+
+                       if(e) {
+                               send_del_edge(mesh, mesh->everyone, e, 0);
+                               edge_del(mesh, e);
+                       }
+               }
        }
-    }
-
-  /* Decrypt the packet */
-
-  if(myself->cipher)
-  {
-    EVP_DecryptInit(&ctx, myself->cipher, myself->key, myself->key + myself->cipher->key_len);
-    EVP_DecryptUpdate(&ctx, (char *)&outpkt.seqno, &outlen, (char *)&inpkt->seqno, inpkt->len);
-    EVP_DecryptFinal(&ctx, (char *)&outpkt.seqno + outlen, &outpad);
-    outlen += outpad;
-    outpkt.len = outlen - sizeof(outpkt.seqno);
-  }
-  else
-  {
-    memcpy((char *)&outpkt.seqno, (char *)&inpkt->seqno, inpkt->len);
-    outpkt.len = inpkt->len - sizeof(outpkt.seqno);
-  }
-
-  if (ntohl(outpkt.seqno) <= n->received_seqno)
-  {
-    syslog(LOG_DEBUG, _("Got late or replayed packet from %s (%s), seqno %d"), n->name, n->hostname, ntohl(*(unsigned int *)&outpkt.seqno));
-    return;
-  }
-  
-  n->received_seqno = ntohl(outpkt.seqno);
-
-  if(n->received_seqno > MAX_SEQNO)
-    keyexpires = 0;
-
-  receive_packet(n, &outpkt);
-cp
-}
 
-void receive_tcppacket(connection_t *c, char *buffer, int len)
-{
-  vpn_packet_t outpkt;
-cp
-  outpkt.len = len;
-  memcpy(outpkt.data, buffer, len);
+       outgoing_t *outgoing = c->outgoing;
+       connection_del(mesh, c);
 
-  receive_packet(c->node, &outpkt);
-cp
-}
+       /* Check if this was our outgoing connection */
 
-void receive_packet(node_t *n, vpn_packet_t *packet)
-{
-cp
-  if(debug_lvl >= DEBUG_TRAFFIC)
-    syslog(LOG_DEBUG, _("Received packet of %d bytes from %s (%s)"), packet->len, n->name, n->hostname);
+       if(outgoing) {
+               do_outgoing_connection(mesh, outgoing);
+       }
 
-  route_incoming(n, packet);
-cp
-}
+#ifndef HAVE_MINGW
+       /* Clean up dead proxy processes */
 
-void send_udppacket(node_t *n, vpn_packet_t *inpkt)
-{
-  vpn_packet_t outpkt;
-  int outlen, outpad;
-  EVP_CIPHER_CTX ctx;
-  struct sockaddr_in to;
-  socklen_t tolen = sizeof(to);
-  vpn_packet_t *copy;
-cp
-  if(!n->status.validkey)
-    {
-      if(debug_lvl >= DEBUG_TRAFFIC)
-       syslog(LOG_INFO, _("No valid key known yet for %s (%s), queueing packet"),
-              n->name, n->hostname);
-
-      /* Since packet is on the stack of handle_tap_input(),
-         we have to make a copy of it first. */
-
-      copy = xmalloc(sizeof(vpn_packet_t));
-      memcpy(copy, inpkt, sizeof(vpn_packet_t));
-
-      list_insert_tail(n->queue, copy);
-
-      if(!n->status.waitingforkey)
-       send_req_key(n->nexthop->connection, myself, n);
-      return;
-    }
-
-  /* Encrypt the packet. */
-
-  inpkt->seqno = htonl(++(n->sent_seqno));
-
-  if(n->cipher)
-  {
-    EVP_EncryptInit(&ctx, n->cipher, n->key, n->key + n->cipher->key_len);
-    EVP_EncryptUpdate(&ctx, (char *)&outpkt.seqno, &outlen, (char *)&inpkt->seqno, inpkt->len + sizeof(inpkt->seqno));
-    EVP_EncryptFinal(&ctx, (char *)&outpkt.seqno + outlen, &outpad);
-    outlen += outpad;
-  }
-  else
-  {
-    memcpy((char *)&outpkt.seqno, (char *)&inpkt->seqno, inpkt->len + sizeof(inpkt->seqno));
-    outlen = inpkt->len + sizeof(inpkt->seqno);
-  }
-
-  if(n->digest && n->maclength)
-    {
-      HMAC(n->digest, n->key, n->keylength, (char *)&outpkt.seqno, outlen, (char *)&outpkt.seqno + outlen, &outpad);
-      outlen += n->maclength;
-    }
-
-  to.sin_family = AF_INET;
-  to.sin_addr.s_addr = htonl(n->address);
-  to.sin_port = htons(n->port);
-
-  if((sendto(udp_socket, (char *)&outpkt.seqno, outlen, 0, (const struct sockaddr *)&to, tolen)) < 0)
-    {
-      syslog(LOG_ERR, _("Error sending packet to %s (%s): %m"),
-             n->name, n->hostname);
-      return;
-    }
-cp
+       while(waitpid(-1, NULL, WNOHANG) > 0);
+
+#endif
 }
 
 /*
-  send a packet to the given vpn ip.
+  Check if the other end is active.
+  If we have sent packets, but didn't receive any,
+  then possibly the other end is dead. We send a
+  PING request over the meta connection. If the other
+  end does not reply in time, we consider them dead
+  and close the connection.
 */
-void send_packet(node_t *n, vpn_packet_t *packet)
-{
-  node_t *via;
-cp
-  if(debug_lvl >= DEBUG_TRAFFIC)
-    syslog(LOG_ERR, _("Sending packet of %d bytes to %s (%s)"),
-           packet->len, n->name, n->hostname);
-
-  if(n == myself)
-    {
-      if(debug_lvl >= DEBUG_TRAFFIC)
-        {
-          syslog(LOG_NOTICE, _("Packet is looping back to us!"));
-        }
-
-      return;
-    }
-  if(!n->status.reachable)
-    {
-      if(debug_lvl >= DEBUG_TRAFFIC)
-       syslog(LOG_INFO, _("Node %s (%s) is not reachable"),
-              n->name, n->hostname);
-      return;
-    }
-
-  via = (n->via == myself)?n->nexthop:n->via;
-
-  if(via != n && debug_lvl >= DEBUG_TRAFFIC)
-    syslog(LOG_ERR, _("Sending packet to %s via %s (%s)"),
-           n->name, via->name, n->via->hostname);
-
-  if((myself->options | via->options) & OPTION_TCPONLY)
-    {
-      if(send_tcppacket(via->connection, packet))
-        terminate_connection(via->connection, 1);
-    }
-  else
-    send_udppacket(via, packet);
+static void timeout_handler(event_loop_t *loop, void *data) {
+       assert(data);
+
+       meshlink_handle_t *mesh = loop->data;
+       logger(mesh, MESHLINK_DEBUG, "timeout_handler()");
+
+       for list_each(connection_t, c, mesh->connections) {
+               int pingtimeout = c->node ? mesh->dev_class_traits[c->node->devclass].pingtimeout : default_timeout;
+               int pinginterval = c->node ? mesh->dev_class_traits[c->node->devclass].pinginterval : default_interval;
+
+               // Also make sure that if outstanding key requests for the UDP counterpart of a connection has timed out, we restart it.
+               if(c->node) {
+                       if(c->node->status.waitingforkey && c->node->last_req_key + pingtimeout <= mesh->loop.now.tv_sec) {
+                               send_req_key(mesh, c->node);
+                       }
+               }
+
+               if(c->last_ping_time + pingtimeout <= mesh->loop.now.tv_sec) {
+                       if(c->status.active) {
+                               if(c->status.pinged) {
+                                       logger(mesh, MESHLINK_INFO, "%s didn't respond to PING in %ld seconds", c->name, (long)mesh->loop.now.tv_sec - c->last_ping_time);
+                               } else if(c->last_ping_time + pinginterval <= mesh->loop.now.tv_sec) {
+                                       send_ping(mesh, c);
+                                       continue;
+                               } else {
+                                       continue;
+                               }
+                       } else {
+                               if(c->status.connecting) {
+                                       logger(mesh, MESHLINK_WARNING, "Timeout while connecting to %s", c->name);
+                               } else {
+                                       logger(mesh, MESHLINK_WARNING, "Timeout from %s during authentication", c->name);
+                               }
+                       }
+
+                       terminate_connection(mesh, c, c->status.active);
+               }
+       }
+
+       timeout_set(&mesh->loop, data, &(struct timeval) {
+               default_timeout, prng(mesh, TIMER_FUDGE)
+       });
 }
 
-/* Broadcast a packet using the minimum spanning tree */
+// devclass asc, last_successfull_connection desc
+static int node_compare_devclass_asc_lsc_desc(const void *a, const void *b) {
+       const node_t *na = a, *nb = b;
 
-void broadcast_packet(node_t *from, vpn_packet_t *packet)
-{
-  avl_node_t *node;
-  connection_t *c;
-cp
-  if(debug_lvl >= DEBUG_TRAFFIC)
-    syslog(LOG_INFO, _("Broadcasting packet of %d bytes from %s (%s)"),
-          packet->len, from->name, from->hostname);
-
-  for(node = connection_tree->head; node; node = node->next)
-    {
-      c = (connection_t *)node->data;
-      if(c->status.active && c->status.mst && c != from->nexthop->connection)
-        send_packet(c->node, packet);
-    }
-cp
-}
+       if(na->devclass < nb->devclass) {
+               return -1;
+       }
 
-void flush_queue(node_t *n)
-{
-  list_node_t *node, *next;
-cp
-  if(debug_lvl >= DEBUG_TRAFFIC)
-    syslog(LOG_INFO, _("Flushing queue for %s (%s)"), n->name, n->hostname);
-
-  for(node = n->queue->head; node; node = next)
-    {
-      next = node->next;
-      send_udppacket(n, (vpn_packet_t *)node->data);
-      list_delete_node(n->queue, node);
-    }
-cp
-}
+       if(na->devclass > nb->devclass) {
+               return 1;
+       }
 
-/* Setup sockets */
+       if(na->last_successfull_connection == nb->last_successfull_connection) {
+               return 0;
+       }
 
-int setup_listen_socket(port_t port)
-{
-  int nfd, flags;
-  struct sockaddr_in a;
-  int option;
-  ipv4_t *address;
-#ifdef HAVE_LINUX
-  char *interface;
-#endif
-cp
-  if((nfd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0)
-    {
-      syslog(LOG_ERR, _("Creating metasocket failed: %m"));
-      return -1;
-    }
-
-  flags = fcntl(nfd, F_GETFL);
-  if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0)
-    {
-      close(nfd);
-      syslog(LOG_ERR, _("System call `%s' failed: %m"),
-            "fcntl");
-      return -1;
-    }
-
-  /* Optimize TCP settings */
-
-  option = 1;
-  setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, &option, sizeof(option));
-  setsockopt(nfd, SOL_SOCKET, SO_KEEPALIVE, &option, sizeof(option));
-#ifdef HAVE_LINUX
-  setsockopt(nfd, SOL_TCP, TCP_NODELAY, &option, sizeof(option));
-
-  option = IPTOS_LOWDELAY;
-  setsockopt(nfd, SOL_IP, IP_TOS, &option, sizeof(option));
-
-  if(get_config_string(lookup_config(config_tree, "BindToInterface"), &interface))
-    if(setsockopt(nfd, SOL_SOCKET, SO_BINDTODEVICE, interface, strlen(interface)))
-      {
-        close(nfd);
-        syslog(LOG_ERR, _("Can't bind to interface %s: %m"), interface);
-        return -1;
-      }
-#endif
+       if(na->last_successfull_connection == 0 || na->last_successfull_connection > nb->last_successfull_connection) {
+               return -1;
+       }
+
+       if(nb->last_successfull_connection == 0 || na->last_successfull_connection < nb->last_successfull_connection) {
+               return 1;
+       }
 
-  memset(&a, 0, sizeof(a));
-  a.sin_family = AF_INET;
-  a.sin_addr.s_addr = htonl(INADDR_ANY);
-  a.sin_port = htons(port);
-
-  if(get_config_address(lookup_config(config_tree, "BindToAddress"), &address))
-    {
-      a.sin_addr.s_addr = htonl(*address);
-      free(address);
-    }
-
-  if(bind(nfd, (struct sockaddr *)&a, sizeof(struct sockaddr)))
-    {
-      close(nfd);
-      syslog(LOG_ERR, _("Can't bind to port %hd/tcp: %m"), port);
-      return -1;
-    }
-
-  if(listen(nfd, 3))
-    {
-      close(nfd);
-      syslog(LOG_ERR, _("System call `%s' failed: %m"),
-            "listen");
-      return -1;
-    }
-cp
-  return nfd;
+       if(na < nb) {
+               return -1;
+       }
+
+       if(na > nb) {
+               return 1;
+       }
+
+       return 0;
 }
 
-int setup_vpn_in_socket(port_t port)
-{
-  int nfd, flags;
-  struct sockaddr_in a;
-  const int one = 1;
-cp
-  if((nfd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0)
-    {
-      close(nfd);
-      syslog(LOG_ERR, _("Creating socket failed: %m"));
-      return -1;
-    }
-
-  setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
-
-  flags = fcntl(nfd, F_GETFL);
-  if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0)
-    {
-      close(nfd);
-      syslog(LOG_ERR, _("System call `%s' failed: %m"),
-            "fcntl");
-      return -1;
-    }
-
-  memset(&a, 0, sizeof(a));
-  a.sin_family = AF_INET;
-  a.sin_port = htons(port);
-  a.sin_addr.s_addr = htonl(INADDR_ANY);
-
-  if(bind(nfd, (struct sockaddr *)&a, sizeof(struct sockaddr)))
-    {
-      close(nfd);
-      syslog(LOG_ERR, _("Can't bind to port %hd/udp: %m"), port);
-      return -1;
-    }
-cp
-  return nfd;
+// last_successfull_connection desc
+static int node_compare_lsc_desc(const void *a, const void *b) {
+       const node_t *na = a, *nb = b;
+
+       if(na->last_successfull_connection == nb->last_successfull_connection) {
+               return 0;
+       }
+
+       if(na->last_successfull_connection == 0 || na->last_successfull_connection > nb->last_successfull_connection) {
+               return -1;
+       }
+
+       if(nb->last_successfull_connection == 0 || na->last_successfull_connection < nb->last_successfull_connection) {
+               return 1;
+       }
+
+       if(na < nb) {
+               return -1;
+       }
+
+       if(na > nb) {
+               return 1;
+       }
+
+       return 0;
 }
 
-void retry_outgoing(outgoing_t *outgoing)
-{
-  event_t *event;
-cp
-  outgoing->timeout += 5;
-  if(outgoing->timeout > maxtimeout)
-    outgoing->timeout = maxtimeout;
-
-  event = new_event();
-  event->handler = (event_handler_t)setup_outgoing_connection;
-  event->time = time(NULL) + outgoing->timeout;
-  event->data = outgoing;
-  event_add(event);
-
-  if(debug_lvl >= DEBUG_CONNECTIONS)
-    syslog(LOG_NOTICE, _("Trying to re-establish outgoing connection in %d seconds"), outgoing->timeout);
-cp
+// devclass desc
+static int node_compare_devclass_desc(const void *a, const void *b) {
+       const node_t *na = a, *nb = b;
+
+       if(na->devclass < nb->devclass) {
+               return -1;
+       }
+
+       if(na->devclass > nb->devclass) {
+               return 1;
+       }
+
+       if(na < nb) {
+               return -1;
+       }
+
+       if(na > nb) {
+               return 1;
+       }
+
+       return 0;
 }
 
-int setup_outgoing_socket(connection_t *c)
+
+/*
+
+autoconnect()
 {
-  int flags;
-  struct sockaddr_in a;
-cp
-  if(debug_lvl >= DEBUG_CONNECTIONS)
-    syslog(LOG_INFO, _("Trying to connect to %s (%s)"), c->name, c->hostname);
+        timeout = 5
 
-  c->socket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
+        // find the best one for initial connect
 
-  if(c->socket == -1)
-    {
-      syslog(LOG_ERR, _("Creating socket for %s port %d failed: %m"),
-             c->hostname, c->port);
-      return -1;
-    }
+        if cur < min
+                newcon =
+                        first from nodes
+                                where dclass <= my.dclass and !connection and (timestamp - last_retry) > retry_timeout
+                                order by dclass asc, last_connection desc
+                if newcon
+                        timeout = 0
+                        goto connect
 
-  /* Bind first to get a fix on our source port???
 
-  a.sin_family = AF_INET;
-  a.sin_port = htons(0);
-  a.sin_addr.s_addr = htonl(INADDR_ANY);
+        // find better nodes to connect to: in case we have less than min connections within [BACKBONE, i] and there are nodes which we are not connected to within the range
 
-  if(bind(c->socket, (struct sockaddr *)&a, sizeof(struct sockaddr)))
-    {
-      close(c->socket);
-      syslog(LOG_ERR, _("System call `%s' failed: %m"), "bind");
-      return -1;
-    }
+        if min <= cur < max
+                j = 0
+                for i = BACKBONE to my.dclass
+                        j += count(from connections where node.dclass = i)
+                        if j < min
+                                newcon =
+                                        first from nodes
+                                                where dclass = i and !connection and (timestamp - last_retry) > retry_timeout
+                                                order by last_connection desc
+                                if newcon
+                                        goto connect
+                        else
+                                break
 
-  */
 
-  /* Optimize TCP settings?
+        // heal partitions
 
-  option = 1;
-  setsockopt(c->socket, SOL_SOCKET, SO_KEEPALIVE, &option, sizeof(option));
-#ifdef HAVE_LINUX
-  setsockopt(c->socket, SOL_TCP, TCP_NODELAY, &option, sizeof(option));
+        if min <= cur < max
+                newcon =
+                        first from nodes
+                                where dclass <= my.dclass and !reachable and (timestamp - last_retry) > retry_timeout
+                                order by dclass asc, last_connection desc
+                if newcon
+                        goto connect
 
-  option = IPTOS_LOWDELAY;
-  setsockopt(c->socket, SOL_IP, IP_TOS, &option, sizeof(option));
-#endif
 
-  */
+        // connect
 
-  /* Connect */
+connect:
+        if newcon
+                connect newcon
 
-  a.sin_family = AF_INET;
-  a.sin_port = htons(c->port);
-  a.sin_addr.s_addr = htonl(c->address);
 
-  if(connect(c->socket, (struct sockaddr *)&a, sizeof(a)) == -1)
-    {
-      close(c->socket);
-      syslog(LOG_ERR, _("%s port %hd: %m"), c->hostname, c->port);
-      return -1;
-    }
+        // disconnect outgoing connections in case we have more than min connections within [BACKBONE, i] and there are nodes which we are connected to within the range [i, PORTABLE]
 
-  flags = fcntl(c->socket, F_GETFL);
+        if min < cur <= max
+                j = 0
+                for i = BACKBONE to my.dclass
+                        j += count(from connections where node.dclass = i)
+                        if min < j
+                                delcon =
+                                        first from nodes
+                                                where dclass >= i and outgoing_connection
+                                                order by dclass desc
+                                if disconnect
+                                        goto disconnect
+                                else
+                                        break
 
-  if(fcntl(c->socket, F_SETFL, flags | O_NONBLOCK) < 0)
-    {
-      close(c->socket);
-      syslog(LOG_ERR, _("fcntl for %s port %d: %m"),
-             c->hostname, c->port);
-      return -1;
-    }
 
-  if(debug_lvl >= DEBUG_CONNECTIONS)
-    syslog(LOG_INFO, _("Connected to %s port %hd"),
-         c->hostname, c->port);
-cp
-  return 0;
-}
+        // disconnect connections in case we have more than enough connections
 
-void setup_outgoing_connection(outgoing_t *outgoing)
-{
-  connection_t *c;
-  node_t *n;
-  struct hostent *h;
-cp
-  n = lookup_node(outgoing->name);
-  
-  if(n)
-    if(n->connection)
-      {
-        if(debug_lvl >= DEBUG_CONNECTIONS)       
-          syslog(LOG_INFO, _("Already connected to %s"), outgoing->name);
-        n->connection->outgoing = outgoing;
-        return;
-      }
-
-  c = new_connection();
-  c->name = xstrdup(outgoing->name);
-
-  init_configuration(&c->config_tree);
-  read_connection_config(c);
-  
-  if(!get_config_string(lookup_config(c->config_tree, "Address"), &c->hostname))
-    {
-      syslog(LOG_ERR, _("No address specified for %s"), c->name);
-      free_connection(c);
-      free(outgoing->name);
-      free(outgoing);
-      return;
-    }
-
-  if(!get_config_port(lookup_config(c->config_tree, "Port"), &c->port))
-    c->port = 655;
-
-  if(!(h = gethostbyname(c->hostname)))
-    {
-      syslog(LOG_ERR, _("Error looking up `%s': %m"), c->hostname);
-      free_connection(c);
-      retry_outgoing(outgoing);
-      return;
-    }
-
-  c->address = ntohl(*((ipv4_t*)(h->h_addr_list[0])));
-  c->hostname = hostlookup(htonl(c->address));
-
-  if(setup_outgoing_socket(c) < 0)
-    {
-      syslog(LOG_ERR, _("Could not set up a meta connection to %s (%s)"),
-             c->name, c->hostname);
-      retry_outgoing(outgoing);
-      return;
-    }
-
-  c->outgoing = outgoing;
-  c->last_ping_time = time(NULL);
-
-  connection_add(c);
-
-  send_id(c);
-cp
-}
+        if max < cur
+                delcon =
+                        first from nodes
+                                where outgoing_connection
+                                order by dclass desc
+                goto disconnect
 
-int read_rsa_public_key(connection_t *c)
-{
-  FILE *fp;
-  char *fname;
-  char *key;
-cp
-  if(!c->rsa_key)
-    c->rsa_key = RSA_new();
-
-  /* First, check for simple PublicKey statement */
-
-  if(get_config_string(lookup_config(c->config_tree, "PublicKey"), &key))
-    {
-      BN_hex2bn(&c->rsa_key->n, key);
-      BN_hex2bn(&c->rsa_key->e, "FFFF");
-      free(key);
-      return 0;
-    }
-
-  /* Else, check for PublicKeyFile statement and read it */
-
-  if(get_config_string(lookup_config(c->config_tree, "PublicKeyFile"), &fname))
-    {
-      if(is_safe_path(fname))
-        {
-          if((fp = fopen(fname, "r")) == NULL)
-            {
-              syslog(LOG_ERR, _("Error reading RSA public key file `%s': %m"),
-                    fname);
-              free(fname);
-              return -1;
-            }
-          free(fname);
-          c->rsa_key = PEM_read_RSAPublicKey(fp, &c->rsa_key, NULL, NULL);
-          fclose(fp);
-          if(!c->rsa_key)
-            {
-              syslog(LOG_ERR, _("Reading RSA public key file `%s' failed: %m"),
-                    fname);
-              return -1;
-            }
-          return 0;
-        }
-      else
-        {
-          free(fname);
-          return -1;
-       }
-    }
-
-  /* Else, check if a harnessed public key is in the config file */
-
-  asprintf(&fname, "%s/hosts/%s", confbase, c->name);
-  if((fp = fopen(fname, "r")))
-    {
-      c->rsa_key = PEM_read_RSAPublicKey(fp, &c->rsa_key, NULL, NULL);
-      fclose(fp);
-    }
-
-  free(fname);
-
-  if(c->rsa_key)
-    return 0;
-  else
-    {
-      syslog(LOG_ERR, _("No public key for %s specified!"), c->name);
-      return -1;
-    }
-}
+        // disconnect
 
-int read_rsa_private_key(void)
-{
-  FILE *fp;
-  char *fname, *key;
-cp
-  if(get_config_string(lookup_config(config_tree, "PrivateKey"), &key))
-    {
-      myself->connection->rsa_key = RSA_new();
-      BN_hex2bn(&myself->connection->rsa_key->d, key);
-      BN_hex2bn(&myself->connection->rsa_key->e, "FFFF");
-      free(key);
-      return 0;
-    }
-
-  if(!get_config_string(lookup_config(config_tree, "PrivateKeyFile"), &fname))
-    asprintf(&fname, "%s/rsa_key.priv", confbase);
-
-  if(is_safe_path(fname))
-    {
-      if((fp = fopen(fname, "r")) == NULL)
-        {
-          syslog(LOG_ERR, _("Error reading RSA private key file `%s': %m"),
-                fname);
-          free(fname);
-          return -1;
-        }
-      free(fname);
-      myself->connection->rsa_key = PEM_read_RSAPrivateKey(fp, NULL, NULL, NULL);
-      fclose(fp);
-      if(!myself->connection->rsa_key)
-        {
-          syslog(LOG_ERR, _("Reading RSA private key file `%s' failed: %m"),
-                fname);
-          return -1;
-        }
-      return 0;
-    }
-
-  free(fname);
-  return -1;
-}
+disconnect
+        if delcon
+                disconnect delcon
+
+
+        // next iteration
+        next (timeout, autoconnect)
 
-int check_rsa_key(RSA *rsa_key)
-{
-  char *test1, *test2, *test3;
-cp
-  if(rsa_key->p && rsa_key->q)
-    {
-      if(RSA_check_key(rsa_key) != 1)
-         return -1;
-    }
-  else
-    {
-      test1 = xmalloc(RSA_size(rsa_key));
-      test2 = xmalloc(RSA_size(rsa_key));
-      test3 = xmalloc(RSA_size(rsa_key));
-
-      if(RSA_public_encrypt(RSA_size(rsa_key), test1, test2, rsa_key, RSA_NO_PADDING) != RSA_size(rsa_key))
-         return -1;
-
-      if(RSA_private_decrypt(RSA_size(rsa_key), test2, test3, rsa_key, RSA_NO_PADDING) != RSA_size(rsa_key))
-         return -1;
-
-      if(memcmp(test1, test3, RSA_size(rsa_key)))
-         return -1;
-    }
-cp
-  return 0;
 }
 
-/*
-  Configure node_t myself and set up the local sockets (listen only)
 */
-int setup_myself(void)
-{
-  config_t *cfg;
-  subnet_t *subnet;
-  char *name, *mode, *cipher, *digest;
-  int choice;
-cp
-  myself = new_node();
-  myself->connection = new_connection();
-  init_configuration(&myself->connection->config_tree);
-
-  asprintf(&myself->hostname, _("MYSELF"));
-  asprintf(&myself->connection->hostname, _("MYSELF"));
-
-  myself->connection->options = 0;
-  myself->connection->protocol_version = PROT_CURRENT;
-
-  if(!get_config_string(lookup_config(config_tree, "Name"), &name)) /* Not acceptable */
-    {
-      syslog(LOG_ERR, _("Name for tinc daemon required!"));
-      return -1;
-    }
-
-  if(check_id(name))
-    {
-      syslog(LOG_ERR, _("Invalid name for myself!"));
-      free(name);
-      return -1;
-    }
-
-  myself->name = name;
-  myself->connection->name = xstrdup(name);
-
-cp
-  if(read_rsa_private_key())
-    return -1;
-
-  if(read_connection_config(myself->connection))
-    {
-      syslog(LOG_ERR, _("Cannot open host configuration file for myself!"));
-      return -1;
-    }
-
-  if(read_rsa_public_key(myself->connection))
-    return -1;
-cp
-
-  if(check_rsa_key(myself->connection->rsa_key))
-    {
-      syslog(LOG_ERR, _("Invalid public/private keypair!"));
-      return -1;
-    }
-
-  if(!get_config_port(lookup_config(myself->connection->config_tree, "Port"), &myself->port))
-    myself->port = 655;
-
-  myself->connection->port = myself->port;
-
-/* Read in all the subnets specified in the host configuration file */
-
-  cfg = lookup_config(myself->connection->config_tree, "Subnet");
-
-  while(cfg)
-    {
-      if(!get_config_subnet(cfg, &subnet))
-        return -1;
-
-      subnet_add(myself, subnet);
-
-      cfg = lookup_config_next(myself->connection->config_tree, cfg);
-    }
-
-cp
-  /* Check some options */
-
-  if(get_config_bool(lookup_config(config_tree, "IndirectData"), &choice))
-    if(choice)
-      myself->options |= OPTION_INDIRECT;
-
-  if(get_config_bool(lookup_config(config_tree, "TCPOnly"), &choice))
-    if(choice)
-      myself->options |= OPTION_TCPONLY;
-
-  if(get_config_bool(lookup_config(myself->connection->config_tree, "IndirectData"), &choice))
-    if(choice)
-      myself->options |= OPTION_INDIRECT;
-
-  if(get_config_bool(lookup_config(myself->connection->config_tree, "TCPOnly"), &choice))
-    if(choice)
-      myself->options |= OPTION_TCPONLY;
-
-  if(myself->options & OPTION_TCPONLY)
-    myself->options |= OPTION_INDIRECT;
-
-  if(get_config_string(lookup_config(config_tree, "Mode"), &mode))
-    {
-      if(!strcasecmp(mode, "router"))
-        routing_mode = RMODE_ROUTER;
-      else if (!strcasecmp(mode, "switch"))
-        routing_mode = RMODE_SWITCH;
-      else if (!strcasecmp(mode, "hub"))
-        routing_mode = RMODE_HUB;
-      else
-        {
-          syslog(LOG_ERR, _("Invalid routing mode!"));
-          return -1;
-        }
-    }
-  else
-    routing_mode = RMODE_ROUTER;
-
-cp
-  /* Open sockets */
-  
-  if((tcp_socket = setup_listen_socket(myself->port)) < 0)
-    {
-      syslog(LOG_ERR, _("Unable to set up a listening TCP socket!"));
-      return -1;
-    }
-
-  if((udp_socket = setup_vpn_in_socket(myself->port)) < 0)
-    {
-      syslog(LOG_ERR, _("Unable to set up a listening UDP socket!"));
-      return -1;
-    }
-cp
-  /* Generate packet encryption key */
-
-  if(get_config_string(lookup_config(myself->connection->config_tree, "Cipher"), &cipher))
-    {
-      if(!strcasecmp(cipher, "none"))
-        {
-         myself->cipher = NULL;
-       }
-      else
-        {
-         if(!(myself->cipher = EVP_get_cipherbyname(cipher)))
-            {
-             syslog(LOG_ERR, _("Unrecognized cipher type!"));
-             return -1;
-           }
-        }
-    }
-  else
-    myself->cipher = EVP_bf_cbc();
-
-  if(myself->cipher)
-    myself->keylength = myself->cipher->key_len + myself->cipher->iv_len;
-  else
-    myself->keylength = 1;
-
-  myself->key = (char *)xmalloc(myself->keylength);
-  RAND_pseudo_bytes(myself->key, myself->keylength);
-
-  if(!get_config_int(lookup_config(config_tree, "KeyExpire"), &keylifetime))
-    keylifetime = 3600;
-
-  keyexpires = time(NULL) + keylifetime;
-
-  /* Check if we want to use message authentication codes... */
-
-  if(get_config_string(lookup_config(myself->connection->config_tree, "Digest"), &digest))
-    {
-      if(!strcasecmp(digest, "none"))
-        {
-         myself->digest = NULL;
-       }
-      else
-        {
-          if(!(myself->digest = EVP_get_digestbyname(digest)))
-           {
-             syslog(LOG_ERR, _("Unrecognized digest type!"));
-             return -1;
-            }
+
+
+static void periodic_handler(event_loop_t *loop, void *data) {
+       meshlink_handle_t *mesh = loop->data;
+
+       /* Check if there are too many contradicting ADD_EDGE and DEL_EDGE messages.
+          This usually only happens when another node has the same Name as this node.
+          If so, sleep for a short while to prevent a storm of contradicting messages.
+       */
+
+       if(mesh->contradicting_del_edge > 100 && mesh->contradicting_add_edge > 100) {
+               logger(mesh, MESHLINK_WARNING, "Possible node with same Name as us! Sleeping %d seconds.", mesh->sleeptime);
+               usleep(mesh->sleeptime * 1000000LL);
+               mesh->sleeptime *= 2;
+
+               if(mesh->sleeptime < 0) {
+                       mesh->sleeptime = 3600;
+               }
+       } else {
+               mesh->sleeptime /= 2;
+
+               if(mesh->sleeptime < 10) {
+                       mesh->sleeptime = 10;
+               }
        }
-    }
-  else
-    myself->digest = EVP_sha1();
-
-  if(get_config_int(lookup_config(myself->connection->config_tree, "MACLength"), &myself->maclength))
-    {
-      if(myself->digest)
-        {
-         if(myself->maclength > myself->digest->md_size)
-            {
-             syslog(LOG_ERR, _("MAC length exceeds size of digest!"));
-             return -1;
-           }
-         else if (myself->maclength < 0)
-            {
-             syslog(LOG_ERR, _("Bogus MAC length!"));
-             return -1;
-           }
-        }
-    }
-  else
-    myself->maclength = 4;
-cp
-  /* Done */
-
-  myself->nexthop = myself;
-  myself->via = myself;
-  myself->status.active = 1;
-  node_add(myself);
-
-  graph();
-
-  syslog(LOG_NOTICE, _("Ready: listening on port %hd"), myself->port);
-cp
-  return 0;
-}
 
-/*
-  setup all initial network connections
-*/
-int setup_network_connections(void)
-{
-cp
-  init_connections();
-  init_subnets();
-  init_nodes();
-  init_edges();
-  init_events();
-
-  if(get_config_int(lookup_config(config_tree, "PingTimeout"), &pingtimeout))
-    {
-      if(pingtimeout < 1)
-        {
-          pingtimeout = 86400;
-        }
-    }
-  else
-    pingtimeout = 60;
-
-  if(setup_device() < 0)
-    return -1;
-
-  /* Run tinc-up script to further initialize the tap interface */
-  execute_script("tinc-up");
-
-  if(setup_myself() < 0)
-    return -1;
-
-  try_outgoing_connections();
-cp
-  return 0;
-}
+       mesh->contradicting_add_edge = 0;
+       mesh->contradicting_del_edge = 0;
 
-/*
-  close all open network connections
-*/
-void close_network_connections(void)
-{
-  avl_node_t *node, *next;
-  connection_t *c;
-cp
-  for(node = connection_tree->head; node; node = next)
-    {
-      next = node->next;
-      c = (connection_t *)node->data;
-      if(c->outgoing)
-        free(c->outgoing->name), free(c->outgoing);
-      terminate_connection(c, 0);
-    }
-
-  if(myself && myself->connection)
-    terminate_connection(myself->connection, 0);
-
-  close(udp_socket);
-  close(tcp_socket);
-
-  exit_events();
-  exit_edges();
-  exit_subnets();
-  exit_nodes();
-  exit_connections();
-
-  execute_script("tinc-down");
-
-  close_device();
-cp
-  return;
-}
+       int timeout = default_timeout;
 
-/*
-  handle an incoming tcp connect call and open
-  a connection to it.
-*/
-connection_t *create_new_connection(int sfd)
-{
-  connection_t *c;
-  struct sockaddr_in ci;
-  int len = sizeof(ci);
-cp
-  c = new_connection();
-
-  if(getpeername(sfd, (struct sockaddr *) &ci, (socklen_t *) &len) < 0)
-    {
-      syslog(LOG_ERR, _("System call `%s' failed: %m"),
-            "getpeername");
-      close(sfd);
-      return NULL;
-    }
-
-  c->address = ntohl(ci.sin_addr.s_addr);
-  c->hostname = hostlookup(ci.sin_addr.s_addr);
-  c->port = htons(ci.sin_port);
-  c->socket = sfd;
-  c->last_ping_time = time(NULL);
-
-  if(debug_lvl >= DEBUG_CONNECTIONS)
-    syslog(LOG_NOTICE, _("Connection from %s port %d"),
-         c->hostname, c->port);
-
-  c->allow_request = ID;
-cp
-  return c;
-}
+       /* Check if we need to make or break connections. */
 
-/*
-  put all file descriptors in an fd_set array
-*/
-void build_fdset(fd_set *fs)
-{
-  avl_node_t *node;
-  connection_t *c;
-cp
-  FD_ZERO(fs);
-
-  for(node = connection_tree->head; node; node = node->next)
-    {
-      c = (connection_t *)node->data;
-      FD_SET(c->socket, fs);
-    }
-
-  FD_SET(tcp_socket, fs);
-  FD_SET(udp_socket, fs);
-  FD_SET(device_fd, fs);
-cp
-}
+       if(mesh->nodes->count > 1) {
 
-/*
-  receive incoming data from the listening
-  udp socket and write it to the ethertap
-  device after being decrypted
-*/
-void handle_incoming_vpn_data(void)
-{
-  vpn_packet_t pkt;
-  int x, l = sizeof(x);
-  struct sockaddr_in from;
-  socklen_t fromlen = sizeof(from);
-  node_t *n;
-cp
-  if(getsockopt(udp_socket, SOL_SOCKET, SO_ERROR, &x, &l) < 0)
-    {
-      syslog(LOG_ERR, _("This is a bug: %s:%d: %d:%m"),
-            __FILE__, __LINE__, udp_socket);
-      return;
-    }
-  if(x)
-    {
-      syslog(LOG_ERR, _("Incoming data socket error: %s"), strerror(x));
-      return;
-    }
-
-  if((pkt.len = recvfrom(udp_socket, (char *)&pkt.seqno, MAXSIZE, 0, (struct sockaddr *)&from, &fromlen)) <= 0)
-    {
-      syslog(LOG_ERR, _("Receiving packet failed: %m"));
-      return;
-    }
-
-  n = lookup_node_udp(ntohl(from.sin_addr.s_addr), ntohs(from.sin_port));
-
-  if(!n)
-    {
-      syslog(LOG_WARNING, _("Received UDP packet on port %hd from unknown source %x:%hd"), myself->port, ntohl(from.sin_addr.s_addr), ntohs(from.sin_port));
-      return;
-    }
+               logger(mesh, MESHLINK_DEBUG, "--- autoconnect begin ---");
 
-/*
-  if(n->connection)
-    n->connection->last_ping_time = time(NULL);
-*/
-  receive_udppacket(n, &pkt);
-cp
-}
+               int retry_timeout = min(mesh->nodes->count * default_timeout, 60);
 
-/* Purge edges and subnets of unreachable nodes. Use carefully. */
+               logger(mesh, MESHLINK_DEBUG, "* devclass = %d", mesh->devclass);
+               logger(mesh, MESHLINK_DEBUG, "* nodes = %d", mesh->nodes->count);
+               logger(mesh, MESHLINK_DEBUG, "* retry_timeout = %d", retry_timeout);
 
-void purge(void)
-{
-  avl_node_t *nnode, *nnext, *enode, *enext, *snode, *snext, *cnode;
-  node_t *n;
-  edge_t *e;
-  subnet_t *s;
-  connection_t *c;
-cp
-  if(debug_lvl >= DEBUG_PROTOCOL)
-    syslog(LOG_DEBUG, _("Purging unreachable nodes"));
-
-  for(nnode = node_tree->head; nnode; nnode = nnext)
-  {
-    nnext = nnode->next;
-    n = (node_t *)nnode->data;
-
-    if(!n->status.reachable)
-    {
-      if(debug_lvl >= DEBUG_SCARY_THINGS)
-        syslog(LOG_DEBUG, _("Purging node %s (%s)"), n->name, n->hostname);
-
-      for(snode = n->subnet_tree->head; snode; snode = snext)
-      {
-        snext = snode->next;
-       s = (subnet_t *)snode->data;
-       
-       for(cnode = connection_tree->head; cnode; cnode = cnode->next)
-       {
-         c = (connection_t *)cnode->data;
-         if(c->status.active)
-           send_del_subnet(c, s);
+
+               // connect disconnect nodes
+
+               node_t *connect_to = NULL;
+               node_t *disconnect_from = NULL;
+
+
+               // get cur_connects
+
+               unsigned int cur_connects = 0;
+
+               for list_each(connection_t, c, mesh->connections) {
+                       if(c->status.active) {
+                               cur_connects += 1;
+                       }
+               }
+
+               logger(mesh, MESHLINK_DEBUG, "* cur_connects = %d", cur_connects);
+               logger(mesh, MESHLINK_DEBUG, "* outgoings = %d", mesh->outgoings->count);
+
+               // get min_connects and max_connects
+
+               unsigned int min_connects = mesh->dev_class_traits[mesh->devclass].min_connects;
+               unsigned int max_connects = mesh->dev_class_traits[mesh->devclass].max_connects;
+
+               logger(mesh, MESHLINK_DEBUG, "* min_connects = %d", min_connects);
+               logger(mesh, MESHLINK_DEBUG, "* max_connects = %d", max_connects);
+
+               // find the best one for initial connect
+
+               if(cur_connects < min_connects) {
+                       splay_tree_t *nodes = splay_alloc_tree(node_compare_devclass_asc_lsc_desc, NULL);
+
+                       for splay_each(node_t, n, mesh->nodes) {
+                               logger(mesh, MESHLINK_DEBUG, "* %s->devclass = %d", n->name, n->devclass);
+
+                               if(n != mesh->self && n->devclass <= mesh->devclass && !n->connection && !n->status.blacklisted && (n->last_connect_try == 0 || (mesh->loop.now.tv_sec - n->last_connect_try) > retry_timeout)) {
+                                       splay_insert(nodes, n);
+                               }
+                       }
+
+                       if(nodes->head) {
+                               //timeout = 0;
+                               connect_to = (node_t *)nodes->head->data;
+
+                               logger(mesh, MESHLINK_DEBUG, "* found best one for initial connect: %s", connect_to->name);
+                       } else {
+                               logger(mesh, MESHLINK_DEBUG, "* could not find node for initial connect");
+                       }
+
+                       splay_delete_tree(nodes);
+               }
+
+
+               // find better nodes to connect to
+
+               if(!connect_to && min_connects <= cur_connects && cur_connects < max_connects) {
+                       unsigned int connects = 0;
+
+                       for(dev_class_t devclass = 0; devclass <= mesh->devclass; ++devclass) {
+                               for list_each(connection_t, c, mesh->connections) {
+                                       if(c->status.active && c->node && c->node->devclass == devclass) {
+                                               connects += 1;
+                                       }
+                               }
+
+                               if(connects < min_connects) {
+                                       splay_tree_t *nodes = splay_alloc_tree(node_compare_lsc_desc, NULL);
+
+                                       for splay_each(node_t, n, mesh->nodes) {
+                                               if(n != mesh->self && n->devclass == devclass && !n->connection && !n->status.blacklisted && (n->last_connect_try == 0 || (mesh->loop.now.tv_sec - n->last_connect_try) > retry_timeout)) {
+                                                       splay_insert(nodes, n);
+                                               }
+                                       }
+
+                                       if(nodes->head) {
+                                               logger(mesh, MESHLINK_DEBUG, "* found better node");
+                                               connect_to = (node_t *)nodes->head->data;
+
+                                               splay_delete_tree(nodes);
+                                               break;
+                                       }
+
+                                       splay_delete_tree(nodes);
+                               } else {
+                                       break;
+                               }
+                       }
+
+                       if(!connect_to) {
+                               logger(mesh, MESHLINK_DEBUG, "* could not find better nodes");
+                       }
+               }
+
+
+               // heal partitions
+
+               if(!connect_to && min_connects <= cur_connects && cur_connects < max_connects) {
+                       splay_tree_t *nodes = splay_alloc_tree(node_compare_devclass_asc_lsc_desc, NULL);
+
+                       for splay_each(node_t, n, mesh->nodes) {
+                               if(n != mesh->self && n->devclass <= mesh->devclass && !n->status.reachable && !n->status.blacklisted && (n->last_connect_try == 0 || (mesh->loop.now.tv_sec - n->last_connect_try) > retry_timeout)) {
+                                       splay_insert(nodes, n);
+                               }
+                       }
+
+                       if(nodes->head) {
+                               logger(mesh, MESHLINK_DEBUG, "* try to heal partition");
+                               connect_to = (node_t *)nodes->head->data;
+                       } else {
+                               logger(mesh, MESHLINK_DEBUG, "* could not find nodes for partition healing");
+                       }
+
+                       splay_delete_tree(nodes);
+               }
+
+
+               // perform connect
+
+               if(connect_to && !connect_to->connection) {
+                       connect_to->last_connect_try = mesh->loop.now.tv_sec;
+                       logger(mesh, MESHLINK_DEBUG, "Autoconnect trying to connect to %s", connect_to->name);
+
+                       /* check if there is already a connection attempt to this node */
+                       bool skip = false;
+
+                       for list_each(outgoing_t, outgoing, mesh->outgoings) {
+                               if(outgoing->node == connect_to) {
+                                       logger(mesh, MESHLINK_DEBUG, "* skip autoconnect since it is an outgoing connection already");
+                                       skip = true;
+                                       break;
+                               }
+                       }
+
+                       if(!connect_to->status.reachable && !node_read_public_key(mesh, connect_to)) {
+                               logger(mesh, MESHLINK_DEBUG, "* skip autoconnect since we don't know this node's public key");
+                               skip = true;
+                       }
+
+                       if(!skip) {
+                               logger(mesh, MESHLINK_DEBUG, "Autoconnecting to %s", connect_to->name);
+                               outgoing_t *outgoing = xzalloc(sizeof(outgoing_t));
+                               outgoing->node = connect_to;
+                               list_insert_tail(mesh->outgoings, outgoing);
+                               setup_outgoing_connection(mesh, outgoing);
+                       }
+               }
+
+
+               // disconnect suboptimal outgoing connections
+
+               if(min_connects < cur_connects /*&& cur_connects <= max_connects*/) {
+                       unsigned int connects = 0;
+
+                       for(dev_class_t devclass = 0; devclass <= mesh->devclass; ++devclass) {
+                               for list_each(connection_t, c, mesh->connections) {
+                                       if(c->status.active && c->node && c->node->devclass == devclass) {
+                                               connects += 1;
+                                       }
+                               }
+
+                               if(min_connects < connects) {
+                                       splay_tree_t *nodes = splay_alloc_tree(node_compare_devclass_desc, NULL);
+
+                                       for list_each(connection_t, c, mesh->connections) {
+                                               if(c->outgoing && c->node && c->node->devclass >= devclass) {
+                                                       splay_insert(nodes, c->node);
+                                               }
+                                       }
+
+                                       if(nodes->head) {
+                                               logger(mesh, MESHLINK_DEBUG, "* disconnect suboptimal outgoing connection");
+                                               disconnect_from = (node_t *)nodes->head->data;
+                                       }
+
+                                       splay_delete_tree(nodes);
+                                       break;
+                               }
+                       }
+
+                       if(!disconnect_from) {
+                               logger(mesh, MESHLINK_DEBUG, "* no suboptimal outgoing connections");
+                       }
+               }
+
+
+               // disconnect connections (too many connections)
+
+               if(!disconnect_from && max_connects < cur_connects) {
+                       splay_tree_t *nodes = splay_alloc_tree(node_compare_devclass_desc, NULL);
+
+                       for list_each(connection_t, c, mesh->connections) {
+                               if(c->status.active && c->node) {
+                                       splay_insert(nodes, c->node);
+                               }
+                       }
+
+                       if(nodes->head) {
+                               logger(mesh, MESHLINK_DEBUG, "* disconnect connection (too many connections)");
+
+                               //timeout = 0;
+                               disconnect_from = (node_t *)nodes->head->data;
+                       } else {
+                               logger(mesh, MESHLINK_DEBUG, "* no node we want to disconnect, even though we have too many connections");
+                       }
+
+                       splay_delete_tree(nodes);
+               }
+
+
+               // perform disconnect
+
+               if(disconnect_from && disconnect_from->connection) {
+                       logger(mesh, MESHLINK_DEBUG, "Autodisconnecting from %s", disconnect_from->connection->name);
+                       list_delete(mesh->outgoings, disconnect_from->connection->outgoing);
+                       disconnect_from->connection->outgoing = NULL;
+                       terminate_connection(mesh, disconnect_from->connection, disconnect_from->connection->status.active);
+               }
+
+               // reduce timeout if we don't have enough connections + outgoings
+               if(cur_connects + mesh->outgoings->count < 3) {
+                       timeout = 1;
+               }
+
+               // done!
+
+               logger(mesh, MESHLINK_DEBUG, "--- autoconnect end ---");
        }
-       
-       subnet_del(n, s);
-      }
-       
-      for(enode = n->edge_tree->head; enode; enode = enext)
-      {
-        enext = enode->next;
-       e = (edge_t *)enode->data;
-       
-       for(cnode = connection_tree->head; cnode; cnode = cnode->next)
-       {
-         c = (connection_t *)cnode->data;
-         if(c->status.active)
-           send_del_edge(c, e);
+
+       for splay_each(node_t, n, mesh->nodes) {
+               if(n->status.dirty) {
+                       node_write_config(mesh, n);
+                       n->status.dirty = false;
+               }
        }
-       
-       edge_del(e);
-      }
-
-      node_del(n);
-    }
-  }    
-cp
-}
 
-/*
-  Terminate a connection:
-  - Close the socket
-  - Remove associated edge and tell other connections about it if report = 1
-  - Check if we need to retry making an outgoing connection
-  - Deactivate the host
-*/
-void terminate_connection(connection_t *c, int report)
-{
-  avl_node_t *node;
-  connection_t *other;
-cp
-  if(c->status.remove)
-    return;
-  
-  if(debug_lvl >= DEBUG_CONNECTIONS)
-    syslog(LOG_NOTICE, _("Closing connection with %s (%s)"),
-           c->name, c->hostname);
-
-  c->status.remove = 1;
-  
-  if(c->socket)
-    close(c->socket);
-
-  if(c->edge)
-    {
-      if(report)
-        {
-          for(node = connection_tree->head; node; node = node->next)
-            {
-              other = (connection_t *)node->data;
-              if(other->status.active && other != c)
-                send_del_edge(other, c->edge);
-            }
-        }
-
-      edge_del(c->edge);
-    }
-
-  /* Run MST and SSSP algorithms */
-  
-  graph();
-
-  /* Check if this was our outgoing connection */
-
-  if(c->outgoing)
-    {
-      retry_outgoing(c->outgoing);
-      c->outgoing = NULL;
-    }
-
-  /* Deactivate */
-
-  c->status.active = 0;
-  if(c->node)
-    c->node->connection = NULL;
-  do_prune = 1;
-cp
+       timeout_set(&mesh->loop, data, &(struct timeval) {
+               timeout, prng(mesh, TIMER_FUDGE)
+       });
 }
 
-/*
-  Check if the other end is active.
-  If we have sent packets, but didn't receive any,
-  then possibly the other end is dead. We send a
-  PING request over the meta connection. If the other
-  end does not reply in time, we consider them dead
-  and close the connection.
-*/
-void check_dead_connections(void)
-{
-  time_t now;
-  avl_node_t *node, *next;
-  connection_t *c;
-cp
-  now = time(NULL);
-
-  for(node = connection_tree->head; node; node = next)
-    {
-      next = node->next;
-      c = (connection_t *)node->data;
-      if(c->last_ping_time + pingtimeout < now)
-        {
-          if(c->status.active)
-            {
-              if(c->status.pinged)
-                {
-                  if(debug_lvl >= DEBUG_PROTOCOL)
-                   syslog(LOG_INFO, _("%s (%s) didn't respond to PING"),
-                          c->name, c->hostname);
-                 c->status.timeout = 1;
-                 terminate_connection(c, 1);
-                }
-              else
-                {
-                  send_ping(c);
-                }
-            }
-          else
-            {
-              if(debug_lvl >= DEBUG_CONNECTIONS)
-                syslog(LOG_WARNING, _("Timeout from %s (%s) during authentication"),
-                       c->name, c->hostname);
-              terminate_connection(c, 0);
-            }
-        }
-    }
-cp
+void handle_meta_connection_data(meshlink_handle_t *mesh, connection_t *c) {
+       if(!receive_meta(mesh, c)) {
+               terminate_connection(mesh, c, c->status.active);
+               return;
+       }
 }
 
-/*
-  accept a new tcp connect and create a
-  new connection
-*/
-int handle_new_meta_connection()
-{
-  connection_t *new;
-  struct sockaddr client;
-  int fd, len = sizeof(client);
-cp
-  if((fd = accept(tcp_socket, &client, &len)) < 0)
-    {
-      syslog(LOG_ERR, _("Accepting a new connection failed: %m"));
-      return -1;
-    }
-
-  if(!(new = create_new_connection(fd)))
-    {
-      shutdown(fd, 2);
-      close(fd);
-      syslog(LOG_NOTICE, _("Closed attempted connection"));
-      return 0;
-    }
-
-  connection_add(new);
-
-  send_id(new);
-cp
-  return 0;
-}
+void retry(meshlink_handle_t *mesh) {
+       /* Reset the reconnection timers for all outgoing connections */
+       for list_each(outgoing_t, outgoing, mesh->outgoings) {
+               outgoing->timeout = 0;
 
-void try_outgoing_connections(void)
-{
-  static config_t *cfg = NULL;
-  char *name;
-  outgoing_t *outgoing;
-cp
-  for(cfg = lookup_config(config_tree, "ConnectTo"); cfg; cfg = lookup_config_next(config_tree, cfg))
-    {
-      get_config_string(cfg, &name);
-
-      if(check_id(name))
-        {
-          syslog(LOG_ERR, _("Invalid name for outgoing connection in %s line %d"), cfg->file, cfg->line);
-          free(name);
-          continue;
-        }
-
-      outgoing = xmalloc_and_zero(sizeof(*outgoing));
-      outgoing->name = name;
-      setup_outgoing_connection(outgoing);
-    }
-}
+               if(outgoing->ev.cb)
+                       timeout_set(&mesh->loop, &outgoing->ev, &(struct timeval) {
+                       0, 0
+               });
+       }
 
-/*
-  check all connections to see if anything
-  happened on their sockets
-*/
-void check_network_activity(fd_set *f)
-{
-  connection_t *c;
-  avl_node_t *node;
-cp
-  if(FD_ISSET(udp_socket, f))
-    handle_incoming_vpn_data();
-
-  for(node = connection_tree->head; node; node = node->next)
-    {
-      c = (connection_t *)node->data;
-
-      if(c->status.remove)
-       return;
-
-      if(FD_ISSET(c->socket, f))
-       if(receive_meta(c) < 0)
-         {
-           terminate_connection(c, c->status.active);
-           return;
-         }
-    }
-
-  if(FD_ISSET(tcp_socket, f))
-    handle_new_meta_connection();
-cp
-}
+#ifdef HAVE_IFADDRS_H
+       struct ifaddrs *ifa = NULL;
+       getifaddrs(&ifa);
+#endif
 
-void prune_connections(void)
-{
-  connection_t *c;
-  avl_node_t *node, *next;
-cp
-  for(node = connection_tree->head; node; node = next)
-    {
-      next = node->next;
-      c = (connection_t *)node->data;
-
-      if(c->status.remove)
-       connection_del(c);
-    }
-  
-  if(!connection_tree->head)
-    purge();
-cp
-}
+       /* For active connections, check if their addresses are still valid.
+        * If yes, reset their ping timers, otherwise terminate them. */
+       for list_each(connection_t, c, mesh->connections) {
+               if(!c->status.active) {
+                       continue;
+               }
 
-/*
-  this is where it all happens...
-*/
-void main_loop(void)
-{
-  fd_set fset;
-  struct timeval tv;
-  int r;
-  time_t last_ping_check;
-  int t;
-  event_t *event;
-  vpn_packet_t packet;
-cp
-  last_ping_check = time(NULL);
-
-  srand(time(NULL));
-
-  for(;;)
-    {
-      tv.tv_sec = 1 + (rand() & 7); /* Approx. 5 seconds, randomized to prevent global synchronisation effects */
-      tv.tv_usec = 0;
-
-      if(do_prune)
-        {
-          prune_connections();
-          do_prune = 0;
-        }
-
-      build_fdset(&fset);
-
-      if((r = select(FD_SETSIZE, &fset, NULL, NULL, &tv)) < 0)
-        {
-         if(errno != EINTR) /* because of a signal */
-            {
-              syslog(LOG_ERR, _("Error while waiting for input: %m"));
-              return;
-            }
-        }
-
-      if(sighup)
-        {
-          syslog(LOG_INFO, _("Rereading configuration file and restarting in 5 seconds"));
-          sighup = 0;
-          close_network_connections();
-          exit_configuration(&config_tree);
-
-          if(read_server_config())
-            {
-              syslog(LOG_ERR, _("Unable to reread configuration file, exiting"));
-              exit(1);
-            }
-
-          sleep(5);
-
-          if(setup_network_connections())
-            return;
-
-          continue;
-        }
-
-      if(do_purge)
-        {
-         purge();
-         do_purge = 0;
-       }
+               if(!c->status.pinged) {
+                       c->last_ping_time = 0;
+               }
 
-      t = time(NULL);
+#ifdef HAVE_IFADDRS_H
 
-      /* Let's check if everybody is still alive */
+               if(!ifa) {
+                       continue;
+               }
 
-      if(last_ping_check + pingtimeout < t)
-       {
-         check_dead_connections();
-          last_ping_check = time(NULL);
+               sockaddr_t sa;
+               socklen_t salen = sizeof(sa);
 
-          /* Should we regenerate our key? */
+               if(getsockname(c->socket, &sa.sa, &salen)) {
+                       continue;
+               }
 
-          if(keyexpires < t)
-            {
-              if(debug_lvl >= DEBUG_STATUS)
-                syslog(LOG_INFO, _("Regenerating symmetric key"));
+               bool found = false;
 
-              RAND_pseudo_bytes(myself->key, myself->keylength);
-              send_key_changed(myself->connection, myself);
-              keyexpires = time(NULL) + keylifetime;
-            }
+               for(struct ifaddrs *ifap = ifa; ifap; ifap = ifap->ifa_next) {
+                       if(ifap->ifa_addr && !sockaddrcmp_noport(&sa, (sockaddr_t *)ifap->ifa_addr)) {
+                               found = true;
+                               break;
+                       }
+
+               }
+
+               if(!found) {
+                       logger(mesh, MESHLINK_DEBUG, "Local address for connection to %s no longer valid, terminating", c->name);
+                       terminate_connection(mesh, c, c->status.active);
+               }
+
+#endif
        }
 
-      if(sigalrm)
-        {
-          syslog(LOG_INFO, _("Flushing event queue"));
-
-         while(event_tree->head)
-           {
-             event = (event_t *)event_tree->head->data;
-             event->handler(event->data);
-             event_del(event);
-           }
-         sigalrm = 0;
-        }
-
-      while((event = get_expired_event()))
-        {
-         event->handler(event->data);
-          free(event);
+#ifdef HAVE_IFADDRS_H
+
+       if(ifa) {
+               freeifaddrs(ifa);
        }
 
-      if(r > 0)
-        {
-          check_network_activity(&fset);
-
-          /* local tap data */
-          if(FD_ISSET(device_fd, &fset))
-            {
-              if(!read_packet(&packet))
-                route_outgoing(&packet);
-            }
-        }
-    }
-cp
+#endif
+
+       /* Kick the ping timeout handler */
+       timeout_set(&mesh->loop, &mesh->pingtimer, &(struct timeval) {
+               0, 0
+       });
+}
+
+/*
+  this is where it all happens...
+*/
+int main_loop(meshlink_handle_t *mesh) {
+       timeout_add(&mesh->loop, &mesh->pingtimer, timeout_handler, &mesh->pingtimer, &(struct timeval) {
+               default_timeout, prng(mesh, TIMER_FUDGE)
+       });
+       timeout_add(&mesh->loop, &mesh->periodictimer, periodic_handler, &mesh->periodictimer, &(struct timeval) {
+               0, 0
+       });
+
+       //Add signal handler
+       mesh->datafromapp.signum = 0;
+       signal_add(&mesh->loop, &mesh->datafromapp, meshlink_send_from_queue, mesh, mesh->datafromapp.signum);
+
+       if(!event_loop_run(&mesh->loop, &mesh->mutex)) {
+               logger(mesh, MESHLINK_ERROR, "Error while waiting for input: %s", strerror(errno));
+               abort();
+               signal_del(&mesh->loop, &mesh->datafromapp);
+               timeout_del(&mesh->loop, &mesh->periodictimer);
+               timeout_del(&mesh->loop, &mesh->pingtimer);
+
+               return 1;
+       }
+
+       signal_del(&mesh->loop, &mesh->datafromapp);
+       timeout_del(&mesh->loop, &mesh->periodictimer);
+       timeout_del(&mesh->loop, &mesh->pingtimer);
+
+       return 0;
 }