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