git.meshlink.io Git - meshlink/blob - src/net.c

   1 /*
   2     net.c -- most of the network code
   3     Copyright (C) 2014 Guus Sliepen <guus@meshlink.io>
   4
   5     This program is free software; you can redistribute it and/or modify
   6     it under the terms of the GNU General Public License as published by
   7     the Free Software Foundation; either version 2 of the License, or
   8     (at your option) any later version.
   9
  10     This program is distributed in the hope that it will be useful,
  11     but WITHOUT ANY WARRANTY; without even the implied warranty of
  12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13     GNU General Public License for more details.
  14
  15     You should have received a copy of the GNU General Public License along
  16     with this program; if not, write to the Free Software Foundation, Inc.,
  17     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18 */
  19
  20 #include "system.h"
  21
  22 #include "utils.h"
  23 #include "conf.h"
  24 #include "connection.h"
  25 #include "graph.h"
  26 #include "logger.h"
  27 #include "meshlink_internal.h"
  28 #include "meta.h"
  29 #include "net.h"
  30 #include "netutl.h"
  31 #include "protocol.h"
  32 #include "xalloc.h"
  33
  34 int contradicting_add_edge = 0;
  35 int contradicting_del_edge = 0;
  36 static int sleeptime = 10;
  37 time_t last_config_check = 0;
  38 static timeout_t pingtimer;
  39 static timeout_t periodictimer;
  40
  41 //TODO: move this to a better place
  42 char *confbase;
  43
  44 /* Purge edges of unreachable nodes. Use carefully. */
  45
  46 // TODO: remove
  47 void purge(void) {
  48         logger(DEBUG_PROTOCOL, LOG_DEBUG, "Purging unreachable nodes");
  49
  50         /* Remove all edges owned by unreachable nodes. */
  51
  52         for splay_each(node_t, n, mesh->nodes) {
  53                 if(!n->status.reachable) {
  54                         logger(DEBUG_SCARY_THINGS, LOG_DEBUG, "Purging node %s (%s)", n->name, n->hostname);
  55
  56                         for splay_each(edge_t, e, n->edge_tree) {
  57                                 send_del_edge(everyone, e);
  58                                 edge_del(e);
  59                         }
  60                 }
  61         }
  62
  63         /* Check if anyone else claims to have an edge to an unreachable node. If not, delete node. */
  64
  65         for splay_each(node_t, n, mesh->nodes) {
  66                 if(!n->status.reachable) {
  67                         for splay_each(edge_t, e, mesh->edges)
  68                                 if(e->to == n)
  69                                         return;
  70                 }
  71         }
  72 }
  73
  74 /*
  75   Terminate a connection:
  76   - Mark it as inactive
  77   - Remove the edge representing this connection
  78   - Kill it with fire
  79   - Check if we need to retry making an outgoing connection
  80 */
  81 void terminate_connection(connection_t *c, bool report) {
  82         logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Closing connection with %s (%s)", c->name, c->hostname);
  83
  84         c->status.active = false;
  85
  86         if(c->node && c->node->connection == c)
  87                 c->node->connection = NULL;
  88
  89         if(c->edge) {
  90                 if(report)
  91                         send_del_edge(everyone, c->edge);
  92
  93                 edge_del(c->edge);
  94                 c->edge = NULL;
  95
  96                 /* Run MST and SSSP algorithms */
  97
  98                 graph();
  99
 100                 /* If the node is not reachable anymore but we remember it had an edge to us, clean it up */
 101
 102                 if(report && !c->node->status.reachable) {
 103                         edge_t *e;
 104                         e = lookup_edge(c->node, mesh->self);
 105                         if(e) {
 106                                 send_del_edge(everyone, e);
 107                                 edge_del(e);
 108                         }
 109                 }
 110         }
 111
 112         outgoing_t *outgoing = c->outgoing;
 113         connection_del(c);
 114
 115         /* Check if this was our outgoing connection */
 116
 117         if(outgoing)
 118                 do_outgoing_connection(outgoing);
 119
 120 #ifndef HAVE_MINGW
 121         /* Clean up dead proxy processes */
 122
 123         while(waitpid(-1, NULL, WNOHANG) > 0);
 124 #endif
 125 }
 126
 127 /*
 128   Check if the other end is active.
 129   If we have sent packets, but didn't receive any,
 130   then possibly the other end is dead. We send a
 131   PING request over the meta connection. If the other
 132   end does not reply in time, we consider them dead
 133   and close the connection.
 134 */
 135 static void timeout_handler(void *data) {
 136         for list_each(connection_t, c, mesh->connections) {
 137                 if(c->last_ping_time + pingtimeout <= now.tv_sec) {
 138                         if(c->status.active) {
 139                                 if(c->status.pinged) {
 140                                         logger(DEBUG_CONNECTIONS, LOG_INFO, "%s (%s) didn't respond to PING in %ld seconds", c->name, c->hostname, (long)now.tv_sec - c->last_ping_time);
 141                                 } else if(c->last_ping_time + pinginterval <= now.tv_sec) {
 142                                         send_ping(c);
 143                                         continue;
 144                                 } else {
 145                                         continue;
 146                                 }
 147                         } else {
 148                                 if(c->status.connecting)
 149                                         logger(DEBUG_CONNECTIONS, LOG_WARNING, "Timeout while connecting to %s (%s)", c->name, c->hostname);
 150                                 else
 151                                         logger(DEBUG_CONNECTIONS, LOG_WARNING, "Timeout from %s (%s) during authentication", c->name, c->hostname);
 152                         }
 153                         terminate_connection(c, c->status.active);
 154                 }
 155         }
 156
 157         timeout_set(data, &(struct timeval){pingtimeout, rand() % 100000});
 158 }
 159
 160 static void periodic_handler(void *data) {
 161         /* Check if there are too many contradicting ADD_EDGE and DEL_EDGE messages.
 162            This usually only happens when another node has the same Name as this node.
 163            If so, sleep for a short while to prevent a storm of contradicting messages.
 164         */
 165
 166         if(contradicting_del_edge > 100 && contradicting_add_edge > 100) {
 167                 logger(DEBUG_ALWAYS, LOG_WARNING, "Possible node with same Name as us! Sleeping %d seconds.", sleeptime);
 168                 usleep(sleeptime * 1000000LL);
 169                 sleeptime *= 2;
 170                 if(sleeptime < 0)
 171                         sleeptime = 3600;
 172         } else {
 173                 sleeptime /= 2;
 174                 if(sleeptime < 10)
 175                         sleeptime = 10;
 176         }
 177
 178         contradicting_add_edge = 0;
 179         contradicting_del_edge = 0;
 180
 181         /* If AutoConnect is set, check if we need to make or break connections. */
 182
 183         if(autoconnect && mesh->nodes->count > 1) {
 184                 /* Count number of active connections */
 185                 int nc = 0;
 186                 for list_each(connection_t, c, mesh->connections) {
 187                         if(c->status.active)
 188                                 nc++;
 189                 }
 190
 191                 if(nc < autoconnect) {
 192                         /* Not enough active connections, try to add one.
 193                            Choose a random node, if we don't have a connection to it,
 194                            and we are not already trying to make one, create an
 195                            outgoing connection to this node.
 196                         */
 197                         int r = rand() % mesh->nodes->count;
 198                         int i = 0;
 199
 200                         for splay_each(node_t, n, mesh->nodes) {
 201                                 if(i++ != r)
 202                                         continue;
 203
 204                                 if(n->connection)
 205                                         break;
 206
 207                                 bool found = false;
 208
 209                                 for list_each(outgoing_t, outgoing, mesh->outgoings) {
 210                                         if(!strcmp(outgoing->name, n->name)) {
 211                                                 found = true;
 212                                                 break;
 213                                         }
 214                                 }
 215
 216                                 if(!found) {
 217                                         logger(DEBUG_CONNECTIONS, LOG_INFO, "Autoconnecting to %s", n->name);
 218                                         outgoing_t *outgoing = xzalloc(sizeof *outgoing);
 219                                         outgoing->name = xstrdup(n->name);
 220                                         list_insert_tail(mesh->outgoings, outgoing);
 221                                         setup_outgoing_connection(outgoing);
 222                                 }
 223                                 break;
 224                         }
 225                 } else if(nc > autoconnect) {
 226                         /* Too many active connections, try to remove one.
 227                            Choose a random outgoing connection to a node
 228                            that has at least one other connection.
 229                         */
 230                         int r = rand() % nc;
 231                         int i = 0;
 232
 233                         for list_each(connection_t, c, mesh->connections) {
 234                                 if(!c->status.active)
 235                                         continue;
 236
 237                                 if(i++ != r)
 238                                         continue;
 239
 240                                 if(!c->outgoing || !c->node || c->node->edge_tree->count < 2)
 241                                         break;
 242
 243                                 logger(DEBUG_CONNECTIONS, LOG_INFO, "Autodisconnecting from %s", c->name);
 244                                 list_delete(mesh->outgoings, c->outgoing);
 245                                 c->outgoing = NULL;
 246                                 terminate_connection(c, c->status.active);
 247                                 break;
 248                         }
 249                 }
 250
 251                 if(nc >= autoconnect) {
 252                         /* If we have enough active connections,
 253                            remove any pending outgoing connections.
 254                         */
 255                         for list_each(outgoing_t, o, mesh->outgoings) {
 256                                 bool found = false;
 257                                 for list_each(connection_t, c, mesh->connections) {
 258                                         if(c->outgoing == o) {
 259                                                 found = true;
 260                                                 break;
 261                                         }
 262                                 }
 263                                 if(!found) {
 264                                         logger(DEBUG_CONNECTIONS, LOG_INFO, "Cancelled outgoing connection to %s", o->name);
 265                                         list_delete_node(mesh->outgoings, node);
 266                                 }
 267                         }
 268                 }
 269         }
 270
 271         timeout_set(data, &(struct timeval){5, rand() % 100000});
 272 }
 273
 274 void handle_meta_connection_data(connection_t *c) {
 275         if (!receive_meta(c)) {
 276                 terminate_connection(c, c->status.active);
 277                 return;
 278         }
 279 }
 280
 281 int reload_configuration(void) {
 282         char *fname = NULL;
 283
 284         /* Reread our own configuration file */
 285
 286         exit_configuration(&mesh->config);
 287         init_configuration(&mesh->config);
 288
 289         if(!read_server_config()) {
 290                 logger(DEBUG_ALWAYS, LOG_ERR, "Unable to reread configuration file.");
 291                 return EINVAL;
 292         }
 293
 294         xasprintf(&fname, "%s" SLASH "hosts" SLASH "%s", confbase, mesh->self->name);
 295         read_config_file(mesh->config, fname);
 296         free(fname);
 297
 298         /* Parse some options that are allowed to be changed while tinc is running */
 299
 300         setup_myself_reloadable();
 301
 302         /* Try to make outgoing connections */
 303
 304         try_outgoing_connections();
 305
 306         /* Close connections to hosts that have a changed or deleted host config file */
 307
 308         for list_each(connection_t, c, mesh->connections) {
 309                 xasprintf(&fname, "%s" SLASH "hosts" SLASH "%s", confbase, c->name);
 310                 struct stat s;
 311                 if(stat(fname, &s) || s.st_mtime > last_config_check) {
 312                         logger(DEBUG_CONNECTIONS, LOG_INFO, "Host config file of %s has been changed", c->name);
 313                         terminate_connection(c, c->status.active);
 314                 }
 315                 free(fname);
 316         }
 317
 318         last_config_check = now.tv_sec;
 319
 320         return 0;
 321 }
 322
 323 void retry(void) {
 324         /* Reset the reconnection timers for all outgoing connections */
 325         for list_each(outgoing_t, outgoing, mesh->outgoings) {
 326                 outgoing->timeout = 0;
 327                 if(outgoing->ev.cb)
 328                         timeout_set(&outgoing->ev, &(struct timeval){0, 0});
 329         }
 330
 331         /* Check for outgoing connections that are in progress, and reset their ping timers */
 332         for list_each(connection_t, c, mesh->connections) {
 333                 if(c->outgoing && !c->node)
 334                         c->last_ping_time = 0;
 335         }
 336
 337         /* Kick the ping timeout handler */
 338         timeout_set(&pingtimer, &(struct timeval){0, 0});
 339 }
 340
 341 /*
 342   this is where it all happens...
 343 */
 344 int main_loop(void) {
 345         timeout_add(&pingtimer, timeout_handler, &pingtimer, &(struct timeval){pingtimeout, rand() % 100000});
 346         timeout_add(&periodictimer, periodic_handler, &periodictimer, &(struct timeval){pingtimeout, rand() % 100000});
 347
 348         if(!event_loop()) {
 349                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while waiting for input: %s", strerror(errno));
 350                 return 1;
 351         }
 352
 353         timeout_del(&periodictimer);
 354         timeout_del(&pingtimer);
 355
 356         return 0;
 357 }