git.meshlink.io Git - meshlink-tiny/blob - src/net_socket.c

   1 /*
   2     net_socket.c -- Handle various kinds of sockets.
   3     Copyright (C) 2014-2017 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 "conf.h"
  23 #include "connection.h"
  24 #include "list.h"
  25 #include "logger.h"
  26 #include "meshlink_internal.h"
  27 #include "meta.h"
  28 #include "net.h"
  29 #include "netutl.h"
  30 #include "protocol.h"
  31 #include "utils.h"
  32 #include "xalloc.h"
  33
  34 /* Needed on Mac OS/X */
  35 #ifndef SOL_TCP
  36 #define SOL_TCP IPPROTO_TCP
  37 #endif
  38
  39 #ifndef MSG_NOSIGNAL
  40 #define MSG_NOSIGNAL 0
  41 #endif
  42
  43 /* Setup sockets */
  44
  45 static void configure_tcp(connection_t *c) {
  46 #ifdef O_NONBLOCK
  47         int flags = fcntl(c->socket, F_GETFL);
  48
  49         if(fcntl(c->socket, F_SETFL, flags | O_NONBLOCK) < 0) {
  50                 logger(c->mesh, MESHLINK_ERROR, "System call `%s' failed: %s", "fcntl", strerror(errno));
  51         }
  52
  53 #elif defined(WIN32)
  54         unsigned long arg = 1;
  55
  56         if(ioctlsocket(c->socket, FIONBIO, &arg) != 0) {
  57                 logger(c->mesh, MESHLINK_ERROR, "System call `%s' failed: %s", "ioctlsocket", sockstrerror(sockerrno));
  58         }
  59
  60 #endif
  61
  62 #if defined(SOL_TCP) && defined(TCP_NODELAY)
  63         int nodelay = 1;
  64         setsockopt(c->socket, SOL_TCP, TCP_NODELAY, (void *)&nodelay, sizeof(nodelay));
  65 #endif
  66
  67 #if defined(IP_TOS) && defined(IPTOS_LOWDELAY)
  68         int lowdelay = IPTOS_LOWDELAY;
  69         setsockopt(c->socket, IPPROTO_IP, IP_TOS, (void *)&lowdelay, sizeof(lowdelay));
  70 #endif
  71
  72 #if defined(SO_NOSIGPIPE)
  73         int nosigpipe = 1;
  74         setsockopt(c->socket, SOL_SOCKET, SO_NOSIGPIPE, (void *)&nosigpipe, sizeof(nosigpipe));
  75 #endif
  76 }
  77
  78 static void retry_outgoing_handler(event_loop_t *loop, void *data) {
  79         assert(data);
  80
  81         meshlink_handle_t *mesh = loop->data;
  82         outgoing_t *outgoing = data;
  83         setup_outgoing_connection(mesh, outgoing);
  84 }
  85
  86 void retry_outgoing(meshlink_handle_t *mesh, outgoing_t *outgoing) {
  87         if(!mesh->reachable && mesh->loop.now.tv_sec < mesh->last_unreachable + mesh->dev_class_traits[outgoing->node->devclass].fast_retry_period) {
  88                 outgoing->timeout = 1;
  89         } else {
  90                 outgoing->timeout += 5;
  91         }
  92
  93         int maxtimeout = mesh->dev_class_traits[outgoing->node->devclass].maxtimeout;
  94
  95         if(outgoing->timeout > maxtimeout) {
  96                 outgoing->timeout = maxtimeout;
  97         }
  98
  99         timeout_add(&mesh->loop, &outgoing->ev, retry_outgoing_handler, outgoing, &(struct timespec) {
 100                 outgoing->timeout, prng(mesh, TIMER_FUDGE)
 101         });
 102
 103         logger(mesh, MESHLINK_INFO, "Trying to re-establish outgoing connection in %d seconds", outgoing->timeout);
 104 }
 105
 106 void finish_connecting(meshlink_handle_t *mesh, connection_t *c) {
 107         logger(mesh, MESHLINK_INFO, "Connected to %s", c->name);
 108
 109         c->last_ping_time = mesh->loop.now.tv_sec;
 110         c->status.connecting = false;
 111
 112         send_id(mesh, c);
 113 }
 114
 115 static void handle_meta_write(meshlink_handle_t *mesh, connection_t *c) {
 116         if(c->outbuf.len <= c->outbuf.offset) {
 117                 return;
 118         }
 119
 120         ssize_t outlen = send(c->socket, c->outbuf.data + c->outbuf.offset, c->outbuf.len - c->outbuf.offset, MSG_NOSIGNAL);
 121
 122         if(outlen <= 0) {
 123                 if(!errno || errno == EPIPE) {
 124                         logger(mesh, MESHLINK_INFO, "Connection closed by %s", c->name);
 125                 } else if(sockwouldblock(sockerrno)) {
 126                         logger(mesh, MESHLINK_DEBUG, "Sending %lu bytes to %s would block", (unsigned long)(c->outbuf.len - c->outbuf.offset), c->name);
 127                         return;
 128                 } else {
 129                         logger(mesh, MESHLINK_ERROR, "Could not send %lu bytes of data to %s: %s", (unsigned long)(c->outbuf.len - c->outbuf.offset), c->name, strerror(errno));
 130                 }
 131
 132                 terminate_connection(mesh, c, c->status.active);
 133                 return;
 134         }
 135
 136         buffer_read(&c->outbuf, outlen);
 137
 138         if(!c->outbuf.len) {
 139                 io_set(&mesh->loop, &c->io, IO_READ);
 140         }
 141 }
 142
 143 void flush_meta(meshlink_handle_t *mesh, connection_t *c) {
 144         handle_meta_write(mesh, c);
 145 }
 146
 147 static void handle_meta_io(event_loop_t *loop, void *data, int flags) {
 148         meshlink_handle_t *mesh = loop->data;
 149         connection_t *c = data;
 150
 151         if(c->status.connecting) {
 152                 c->status.connecting = false;
 153
 154                 int result;
 155                 socklen_t len = sizeof(result);
 156                 getsockopt(c->socket, SOL_SOCKET, SO_ERROR, (void *)&result, &len);
 157
 158                 if(!result) {
 159                         finish_connecting(mesh, c);
 160                 } else {
 161                         logger(mesh, MESHLINK_ERROR, "Error while connecting to %s: %s", c->name, sockstrerror(result));
 162                         terminate_connection(mesh, c, false);
 163                         return;
 164                 }
 165         }
 166
 167         if(flags & IO_WRITE) {
 168                 handle_meta_write(mesh, c);
 169         } else {
 170                 handle_meta_connection_data(mesh, c);
 171         }
 172 }
 173
 174 // Build a list of recently seen addresses.
 175 static struct addrinfo *get_recent_addresses(node_t *n) {
 176         struct addrinfo *ai = NULL;
 177         struct addrinfo *aip;
 178
 179         for(int i = 0; i < 5; i++) {
 180                 if(!n->recent[i].sa.sa_family) {
 181                         break;
 182                 }
 183
 184                 // Create a new struct addrinfo, and put it at the end of the list.
 185                 struct addrinfo *nai = xzalloc(sizeof(*nai) + SALEN(n->recent[i].sa));
 186
 187                 if(!ai) {
 188                         ai = nai;
 189                 } else {
 190                         aip->ai_next = nai;
 191                 }
 192
 193                 aip = nai;
 194
 195                 nai->ai_family = n->recent[i].sa.sa_family;
 196                 nai->ai_socktype = SOCK_STREAM;
 197                 nai->ai_protocol = IPPROTO_TCP;
 198                 nai->ai_addrlen = SALEN(n->recent[i].sa);
 199                 nai->ai_addr = (struct sockaddr *)(nai + 1);
 200                 memcpy(nai->ai_addr, &n->recent[i], nai->ai_addrlen);
 201         }
 202
 203         return ai;
 204 }
 205
 206 // Free struct addrinfo list from get_known_addresses().
 207 static void free_known_addresses(struct addrinfo *ai) {
 208         for(struct addrinfo *aip = ai, *next; aip; aip = next) {
 209                 next = aip->ai_next;
 210                 free(aip);
 211         }
 212 }
 213
 214 static bool get_next_outgoing_address(meshlink_handle_t *mesh, outgoing_t *outgoing) {
 215         (void)mesh;
 216
 217         bool start = false;
 218
 219         if(outgoing->state == OUTGOING_START) {
 220                 start = true;
 221                 outgoing->state = OUTGOING_CANONICAL_RESOLVE;
 222         }
 223
 224         if(outgoing->state == OUTGOING_CANONICAL_RESOLVE) {
 225                 node_t *n = outgoing->node;
 226
 227                 if(n->canonical_address) {
 228                         char *address = xstrdup(n->canonical_address);
 229                         char *port = strchr(address, ' ');
 230
 231                         if(port) {
 232                                 *port++ = 0;
 233                                 outgoing->ai = str2addrinfo(address, port, SOCK_STREAM);
 234                                 outgoing->aip = NULL;
 235                                 outgoing->state = OUTGOING_CANONICAL;
 236                         } else {
 237                                 logger(mesh, MESHLINK_ERROR, "Canonical address for %s is missing port number", n->name);
 238                                 outgoing->state = OUTGOING_RECENT;
 239                         }
 240
 241                         free(address);
 242                 } else {
 243                         outgoing->state = OUTGOING_RECENT;
 244                 }
 245         }
 246
 247         if(outgoing->state == OUTGOING_CANONICAL) {
 248                 if(!outgoing->aip) {
 249                         outgoing->aip = outgoing->ai;
 250                 } else {
 251                         outgoing->aip = outgoing->aip->ai_next;
 252                 }
 253
 254                 if(outgoing->aip) {
 255                         return true;
 256                 }
 257
 258                 if(outgoing->ai) {
 259                         freeaddrinfo(outgoing->ai);
 260                 }
 261
 262                 outgoing->ai = NULL;
 263                 outgoing->aip = NULL;
 264                 outgoing->state = OUTGOING_END;
 265         }
 266
 267         if(outgoing->state == OUTGOING_RECENT) {
 268                 if(!outgoing->aip) {
 269                         outgoing->ai = get_recent_addresses(outgoing->node);
 270                         outgoing->aip = outgoing->ai;
 271                 } else {
 272                         outgoing->aip = outgoing->aip->ai_next;
 273                 }
 274
 275                 if(outgoing->aip) {
 276                         return true;
 277                 }
 278
 279                 free_known_addresses(outgoing->ai);
 280                 outgoing->ai = NULL;
 281                 outgoing->aip = NULL;
 282                 outgoing->state = OUTGOING_END;
 283         }
 284
 285         if(start) {
 286                 outgoing->state = OUTGOING_NO_KNOWN_ADDRESSES;
 287         }
 288
 289         return false;
 290 }
 291
 292 static void free_outgoing(outgoing_t *outgoing) {
 293         meshlink_handle_t *mesh = outgoing->node->mesh;
 294
 295         timeout_del(&mesh->loop, &outgoing->ev);
 296
 297         if(outgoing->ai) {
 298                 if(outgoing->state == OUTGOING_RECENT || outgoing->state == OUTGOING_KNOWN) {
 299                         free_known_addresses(outgoing->ai);
 300                 } else {
 301                         freeaddrinfo(outgoing->ai);
 302                 }
 303         }
 304
 305         free(outgoing);
 306 }
 307
 308 void do_outgoing_connection(meshlink_handle_t *mesh, outgoing_t *outgoing) {
 309 begin:
 310
 311         if(!get_next_outgoing_address(mesh, outgoing)) {
 312                 if(outgoing->state == OUTGOING_CANONICAL_RESOLVE) {
 313                         /* We are waiting for a callback from the ADNS thread */
 314                 } else if(outgoing->state == OUTGOING_NO_KNOWN_ADDRESSES) {
 315                         logger(mesh, MESHLINK_ERROR, "No known addresses for %s", outgoing->node->name);
 316                         free_outgoing(outgoing);
 317                         mesh->outgoing = NULL;
 318                 } else {
 319                         logger(mesh, MESHLINK_ERROR, "Could not set up a meta connection to %s", outgoing->node->name);
 320                         retry_outgoing(mesh, outgoing);
 321                 }
 322
 323                 return;
 324         }
 325
 326         connection_t *c = new_connection();
 327         c->outgoing = outgoing;
 328
 329         memcpy(&c->address, outgoing->aip->ai_addr, outgoing->aip->ai_addrlen);
 330
 331         if(mesh->log_level <= MESHLINK_INFO) {
 332                 char *hostname = sockaddr2hostname(&c->address);
 333                 logger(mesh, MESHLINK_INFO, "Trying to connect to %s at %s", outgoing->node->name, hostname);
 334                 free(hostname);
 335         }
 336
 337         c->socket = socket(c->address.sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 338
 339         if(c->socket == -1) {
 340                 if(mesh->log_level <= MESHLINK_ERROR) {
 341                         char *hostname = sockaddr2hostname(&c->address);
 342                         logger(mesh, MESHLINK_ERROR, "Creating socket for %s at %s failed: %s", c->name, hostname, sockstrerror(sockerrno));
 343                         free(hostname);
 344                 }
 345
 346                 free_connection(c);
 347                 goto begin;
 348         }
 349
 350         configure_tcp(c);
 351
 352 #ifdef FD_CLOEXEC
 353         fcntl(c->socket, F_SETFD, FD_CLOEXEC);
 354 #endif
 355
 356 #if defined(IPV6_V6ONLY)
 357
 358         if(c->address.sa.sa_family == AF_INET6) {
 359                 static const int option = 1;
 360                 setsockopt(c->socket, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof(option));
 361         }
 362
 363 #endif
 364
 365         /* Connect */
 366
 367         int result = connect(c->socket, &c->address.sa, SALEN(c->address.sa));
 368
 369         if(result == -1 && !sockinprogress(sockerrno)) {
 370                 if(mesh->log_level <= MESHLINK_ERROR) {
 371                         char *hostname = sockaddr2hostname(&c->address);
 372                         logger(mesh, MESHLINK_ERROR, "Could not connect to %s: %s", outgoing->node->name, sockstrerror(sockerrno));
 373                         free(hostname);
 374                 }
 375
 376                 free_connection(c);
 377                 goto begin;
 378         }
 379
 380         /* Now that there is a working socket, fill in the rest and register this connection. */
 381
 382         c->status.connecting = true;
 383         c->status.initiator = true;
 384         c->name = xstrdup(outgoing->node->name);
 385         c->last_ping_time = mesh->loop.now.tv_sec;
 386
 387         connection_add(mesh, c);
 388
 389         io_add(&mesh->loop, &c->io, handle_meta_io, c, c->socket, IO_READ | IO_WRITE);
 390 }
 391
 392 void reset_outgoing(outgoing_t *outgoing) {
 393         if(outgoing->ai) {
 394                 if(outgoing->state == OUTGOING_RECENT || outgoing->state == OUTGOING_KNOWN) {
 395                         free_known_addresses(outgoing->ai);
 396                 } else {
 397                         freeaddrinfo(outgoing->ai);
 398                 }
 399         }
 400
 401         outgoing->ai = NULL;
 402         outgoing->aip = NULL;
 403         outgoing->state = OUTGOING_START;
 404 }
 405
 406 void setup_outgoing_connection(meshlink_handle_t *mesh, outgoing_t *outgoing) {
 407         timeout_del(&mesh->loop, &outgoing->ev);
 408
 409         if(outgoing->node->connection) {
 410                 logger(mesh, MESHLINK_INFO, "Already connected to %s", outgoing->node->name);
 411
 412                 outgoing->node->connection->outgoing = outgoing;
 413                 return;
 414         }
 415
 416         reset_outgoing(outgoing);
 417
 418         if(outgoing->node->status.blacklisted) {
 419                 return;
 420         }
 421
 422         if(mesh->connection_try_cb) {
 423                 mesh->connection_try_cb(mesh, (meshlink_node_t *)outgoing->node);
 424         }
 425
 426         do_outgoing_connection(mesh, outgoing);
 427 }
 428
 429 void init_outgoings(meshlink_handle_t *mesh) {
 430         mesh->outgoing = NULL;
 431 }
 432
 433 void exit_outgoings(meshlink_handle_t *mesh) {
 434         if(mesh->outgoing) {
 435                 free_outgoing(mesh->outgoing);
 436                 mesh->outgoing = NULL;
 437         }
 438 }