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