2 This file is part of GNUnet
3 (C) 2010 Christian Grothoff (and other contributing authors)
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6 it under the terms of the GNU General Public License as published
7 by the Free Software Foundation; either version 2, or (at your
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12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 General Public License for more details.
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22 * @file transport/plugin_transport_udp.c
23 * @brief Implementation of the UDP transport service
24 * @author Christian Grothoff
25 * @author Nathan Evans
29 #include "gnunet_hello_lib.h"
30 #include "gnunet_connection_lib.h"
31 #include "gnunet_os_lib.h"
32 #include "gnunet_peerinfo_service.h"
33 #include "gnunet_protocols.h"
34 #include "gnunet_resolver_service.h"
35 #include "gnunet_server_lib.h"
36 #include "gnunet_service_lib.h"
37 #include "gnunet_signatures.h"
38 #include "gnunet_statistics_service.h"
39 #include "gnunet_transport_service.h"
40 #include "plugin_transport.h"
41 #include "transport.h"
43 #define DEBUG_UDP GNUNET_NO
46 * Transport cost to peer, always 1 for UDP (direct connection)
48 #define UDP_DIRECT_DISTANCE 1
51 * Handle for request of hostname resolution, non-NULL if pending.
53 static struct GNUNET_RESOLVER_RequestHandle *hostname_dns;
56 * How long until we give up on transmitting the welcome message?
58 #define HOSTNAME_RESOLVE_TIMEOUT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 5)
62 * Message-Packet header.
67 * size of the message, in bytes, including this header.
69 struct GNUNET_MessageHeader header;
72 * What is the identity of the sender (GNUNET_hash of public key)
74 struct GNUNET_PeerIdentity sender;
78 /* Forward definition */
81 struct PrettyPrinterContext
83 GNUNET_TRANSPORT_AddressStringCallback asc;
89 * Encapsulation of all of the state of the plugin.
96 struct GNUNET_TRANSPORT_PluginEnvironment *env;
99 * Handle for the statistics service.
101 struct GNUNET_STATISTICS_Handle *statistics;
104 * Handle to the network service.
106 struct GNUNET_SERVICE_Context *service;
109 * Handle for request of hostname resolution, non-NULL if pending.
111 struct GNUNET_RESOLVER_RequestHandle *hostname_dns;
114 * ID of task used to update our addresses when one expires.
116 GNUNET_SCHEDULER_TaskIdentifier address_update_task;
121 GNUNET_SCHEDULER_TaskIdentifier select_task;
124 * Port that we are actually listening on.
129 * Port that the user said we would have visible to the
137 struct GNUNET_NETWORK_FDSet *rs;
141 /* *********** globals ************* */
144 * the socket that we transmit all data with
146 static struct GNUNET_NETWORK_Handle *udp_sock;
149 * Disconnect from a remote node.
151 * @param tsession the session that is closed
152 * @return GNUNET_OK on success, GNUNET_SYSERR if the operation failed
155 udp_disconnect (void *cls, const struct GNUNET_PeerIdentity *target)
161 * Shutdown the server process (stop receiving inbound traffic). Maybe
165 udp_transport_server_stop (void *cls)
167 struct Plugin *plugin = cls;
168 GNUNET_assert (udp_sock != NULL);
169 if (plugin->select_task != GNUNET_SCHEDULER_NO_TASK)
171 GNUNET_SCHEDULER_cancel (plugin->env->sched, plugin->select_task);
172 plugin->select_task = GNUNET_SCHEDULER_NO_TASK;
175 GNUNET_NETWORK_socket_close (udp_sock);
181 * Function that can be used by the transport service to transmit
182 * a message using the plugin.
185 * @param target who should receive this message (ignored by UDP)
186 * @param msg the message to transmit
187 * @param priority how important is the message (ignored by UDP)
188 * @param timeout when should we time out (give up) if we can not transmit?
189 * @param addr the addr to send the message to, needs to be a sockaddr for us
190 * @param addrlen the len of addr
191 * @param force_address not used, we had better have an address to send to
192 * because we are stateless!!
193 * @param cont continuation to call once the message has
194 * been transmitted (or if the transport is ready
195 * for the next transmission call; or if the
196 * peer disconnected...)
197 * @param cont_cls closure for cont
199 * @return the number of bytes written
203 udp_plugin_send (void *cls,
204 const struct GNUNET_PeerIdentity *target,
205 const struct GNUNET_MessageHeader *msg,
206 unsigned int priority,
207 struct GNUNET_TIME_Relative timeout,
211 GNUNET_TRANSPORT_TransmitContinuation cont, void *cont_cls)
213 struct Plugin *plugin = cls;
214 struct UDPMessage *message;
218 GNUNET_assert(udp_sock != NULL);
219 GNUNET_assert(addr != NULL);
221 /* Build the message to be sent */
222 message = GNUNET_malloc (sizeof (struct UDPMessage) + ntohs (msg->size));
223 ssize = sizeof (struct UDPMessage) + ntohs (msg->size);
226 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
227 ("In udp_send, ssize is %d\n"), ssize);
229 message->header.size = htons (ssize);
230 message->header.type = htons (0);
231 memcpy (&message->sender, plugin->env->my_identity,
232 sizeof (struct GNUNET_PeerIdentity));
233 memcpy (&message[1], msg, ntohs (msg->size));
235 /* Actually send the message */
237 GNUNET_NETWORK_socket_sendto (udp_sock, message, ssize,
243 if (sent == GNUNET_SYSERR)
244 cont (cont_cls, target, GNUNET_SYSERR);
246 cont (cont_cls, target, GNUNET_OK);
248 GNUNET_free (message);
254 * Add the IP of our network interface to the list of
255 * our external IP addresses.
258 process_interfaces (void *cls,
261 const struct sockaddr *addr, socklen_t addrlen)
263 struct Plugin *plugin = cls;
265 struct sockaddr_in *v4;
266 struct sockaddr_in6 *v6;
268 af = addr->sa_family;
271 v4 = (struct sockaddr_in *) addr;
272 v4->sin_port = htons (plugin->adv_port);
276 GNUNET_assert (af == AF_INET6);
277 v6 = (struct sockaddr_in6 *) addr;
278 v6->sin6_port = htons (plugin->adv_port);
280 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO |
281 GNUNET_ERROR_TYPE_BULK,
282 "udp", _("Found address `%s' (%s)\n"),
283 GNUNET_a2s (addr, addrlen), name);
284 plugin->env->notify_address (plugin->env->cls,
286 addr, addrlen, GNUNET_TIME_UNIT_FOREVER_REL);
293 * Function called by the resolver for each address obtained from DNS
294 * for our own hostname. Add the addresses to the list of our
295 * external IP addresses.
298 * @param addr one of the addresses of the host, NULL for the last address
299 * @param addrlen length of the address
302 process_hostname_ips (void *cls,
303 const struct sockaddr *addr, socklen_t addrlen)
305 struct Plugin *plugin = cls;
309 plugin->hostname_dns = NULL;
312 process_interfaces (plugin, "<hostname>", GNUNET_YES, addr, addrlen);
317 * @param cls the plugin handle
318 * @param tc the scheduling context (for rescheduling this function again)
320 * We have been notified that our writeset has something to read. Presumably
321 * select has been called already, so we can go ahead and start reading from
322 * the socket immediately. Then we check if there is more to be read by
323 * calling select ourselves while there is stuff on the wire. Then reschedule
324 * this function to be called again once more is available.
328 udp_plugin_select (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
330 struct Plugin *plugin = cls;
331 struct GNUNET_TIME_Relative timeout =
332 GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MILLISECONDS, 500);
334 struct UDPMessage *msg;
335 const struct GNUNET_MessageHeader *hdr;
336 struct GNUNET_PeerIdentity *sender;
339 struct sockaddr_storage addr;
344 buflen = GNUNET_NETWORK_socket_recvfrom_amount (udp_sock);
347 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
348 ("we expect to read %u bytes\n"), buflen);
351 if (buflen == GNUNET_NO)
354 buf = GNUNET_malloc (buflen);
355 fromlen = sizeof (addr);
357 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
358 ("src_addr_len is %u\n"), fromlen);
360 memset (&addr, 0, fromlen);
362 GNUNET_NETWORK_socket_recvfrom (udp_sock, buf, buflen,
363 (struct sockaddr *) &addr, &fromlen);
366 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
367 ("socket_recv returned %u, src_addr_len is %u\n"), ret,
376 msg = (struct UDPMessage *) buf;
379 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
380 ("header reports message size of %d\n"),
381 ntohs (msg->header.size));
383 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
384 ("header reports message type of %d\n"),
385 ntohs (msg->header.type));
387 if (ntohs (msg->header.size) < sizeof (struct UDPMessage))
390 GNUNET_NETWORK_fdset_zero (plugin->rs);
391 GNUNET_NETWORK_fdset_set (plugin->rs, udp_sock);
394 hdr = (const struct GNUNET_MessageHeader *) &msg[1];
395 sender = GNUNET_malloc (sizeof (struct GNUNET_PeerIdentity));
396 memcpy (sender, &msg->sender, sizeof (struct GNUNET_PeerIdentity));
399 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
400 ("msg reports message size of %d\n"),
403 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
404 ("msg reports message type of %d\n"),
407 plugin->env->receive (plugin->env->cls,
408 sender, &msg->header, UDP_DIRECT_DISTANCE, (char *)&addr, fromlen);
410 GNUNET_free (sender);
414 while (GNUNET_NETWORK_socket_select (plugin->rs,
418 && GNUNET_NETWORK_fdset_isset (plugin->rs, udp_sock));
420 plugin->select_task =
421 GNUNET_SCHEDULER_add_select (plugin->env->sched,
422 GNUNET_SCHEDULER_PRIORITY_DEFAULT,
423 GNUNET_SCHEDULER_NO_TASK,
424 GNUNET_TIME_UNIT_FOREVER_REL, plugin->rs,
425 NULL, &udp_plugin_select, plugin);
430 * Create a UDP socket. If possible, use IPv6, otherwise
433 static struct GNUNET_NETWORK_Handle *
434 udp_transport_server_start (void *cls)
436 struct Plugin *plugin = cls;
437 struct GNUNET_NETWORK_Handle *desc;
438 struct sockaddr_in serverAddrv4;
439 struct sockaddr_in6 serverAddrv6;
440 struct sockaddr *serverAddr;
445 GNUNET_CONFIGURATION_get_value_yesno (plugin->env->cfg, "GNUNETD",
448 desc = GNUNET_NETWORK_socket_create (PF_INET6, SOCK_DGRAM, 17);
451 memset (&serverAddrv6, 0, sizeof (serverAddrv6));
452 #if HAVE_SOCKADDR_IN_SIN_LEN
453 serverAddrv6.sin6_len = sizeof (serverAddrv6);
455 serverAddrv6.sin6_family = AF_INET6;
456 serverAddrv6.sin6_addr = in6addr_any;
457 serverAddrv6.sin6_port = htons (plugin->open_port);
458 addrlen = sizeof (serverAddrv6);
459 serverAddr = (struct sockaddr *) &serverAddrv6;
464 desc = GNUNET_NETWORK_socket_create (PF_INET, SOCK_DGRAM, 17);
467 GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "udp", "socket");
472 memset (&serverAddrv4, 0, sizeof (serverAddrv4));
473 #if HAVE_SOCKADDR_IN_SIN_LEN
474 serverAddrv4.sin_len = sizeof (serverAddrv4);
476 serverAddrv4.sin_family = AF_INET;
477 serverAddrv4.sin_addr.s_addr = INADDR_ANY;
478 serverAddrv4.sin_port = htons (plugin->open_port);
479 addrlen = sizeof (serverAddrv4);
480 serverAddr = (struct sockaddr *) &serverAddrv4;
486 GNUNET_assert (GNUNET_NETWORK_socket_bind (desc, serverAddr, addrlen) ==
490 plugin->rs = GNUNET_NETWORK_fdset_create ();
492 GNUNET_NETWORK_fdset_zero (plugin->rs);
493 GNUNET_NETWORK_fdset_set (plugin->rs, desc);
495 plugin->select_task =
496 GNUNET_SCHEDULER_add_select (plugin->env->sched,
497 GNUNET_SCHEDULER_PRIORITY_DEFAULT,
498 GNUNET_SCHEDULER_NO_TASK,
499 GNUNET_TIME_UNIT_FOREVER_REL, plugin->rs,
500 NULL, &udp_plugin_select, plugin);
507 * Check if the given port is plausible (must be either
508 * our listen port or our advertised port). If it is
509 * neither, we return one of these two ports at random.
511 * @return either in_port or a more plausible port
514 check_port (struct Plugin *plugin, uint16_t in_port)
516 if ((in_port == plugin->adv_port) || (in_port == plugin->open_port))
518 return (GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK,
520 ? plugin->open_port : plugin->adv_port;
525 * Another peer has suggested an address for this peer and transport
526 * plugin. Check that this could be a valid address. This function
527 * is not expected to 'validate' the address in the sense of trying to
528 * connect to it but simply to see if the binary format is technically
529 * legal for establishing a connection.
531 * @param addr pointer to the address, may be modified (slightly)
532 * @param addrlen length of addr
533 * @return GNUNET_OK if this is a plausible address for this peer
534 * and transport, GNUNET_SYSERR if not
536 * TODO: perhaps make everything work with sockaddr_storage, it may
537 * be a cleaner way to handle addresses in UDP
540 udp_check_address (void *cls, void *addr, size_t addrlen)
542 struct Plugin *plugin = cls;
543 char buf[sizeof (struct sockaddr_in6)];
545 struct sockaddr_in *v4;
546 struct sockaddr_in6 *v6;
548 if ((addrlen != sizeof (struct sockaddr_in)) &&
549 (addrlen != sizeof (struct sockaddr_in6)))
552 return GNUNET_SYSERR;
554 memcpy (buf, addr, sizeof (struct sockaddr_in6));
555 if (addrlen == sizeof (struct sockaddr_in))
557 v4 = (struct sockaddr_in *) buf;
558 v4->sin_port = htons (check_port (plugin, ntohs (v4->sin_port)));
562 v6 = (struct sockaddr_in6 *) buf;
563 v6->sin6_port = htons (check_port (plugin, ntohs (v6->sin6_port)));
566 GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG,
568 "Informing transport service about my address `%s'.\n",
569 GNUNET_a2s (addr, addrlen));
577 * Append our port and forward the result.
580 append_port (void *cls, const char *hostname)
582 struct PrettyPrinterContext *ppc = cls;
585 if (hostname == NULL)
587 ppc->asc (ppc->asc_cls, NULL);
591 GNUNET_asprintf (&ret, "%s:%d", hostname, ppc->port);
592 ppc->asc (ppc->asc_cls, ret);
598 * Convert the transports address to a nice, human-readable
602 * @param type name of the transport that generated the address
603 * @param addr one of the addresses of the host, NULL for the last address
604 * the specific address format depends on the transport
605 * @param addrlen length of the address
606 * @param numeric should (IP) addresses be displayed in numeric form?
607 * @param timeout after how long should we give up?
608 * @param asc function to call on each string
609 * @param asc_cls closure for asc
612 udp_plugin_address_pretty_printer (void *cls,
617 struct GNUNET_TIME_Relative timeout,
618 GNUNET_TRANSPORT_AddressStringCallback asc,
621 struct Plugin *plugin = cls;
622 const struct sockaddr_in *v4;
623 const struct sockaddr_in6 *v6;
624 struct PrettyPrinterContext *ppc;
626 if ((addrlen != sizeof (struct sockaddr_in)) &&
627 (addrlen != sizeof (struct sockaddr_in6)))
629 /* invalid address */
634 ppc = GNUNET_malloc (sizeof (struct PrettyPrinterContext));
636 ppc->asc_cls = asc_cls;
637 if (addrlen == sizeof (struct sockaddr_in))
639 v4 = (const struct sockaddr_in *) addr;
640 ppc->port = ntohs (v4->sin_port);
644 v6 = (const struct sockaddr_in6 *) addr;
645 ppc->port = ntohs (v6->sin6_port);
648 GNUNET_RESOLVER_hostname_get (plugin->env->sched,
652 !numeric, timeout, &append_port, ppc);
656 * Set a quota for receiving data from the given peer; this is a
657 * per-transport limit. This call has no meaning for UDP, as if
658 * we don't receive data it still comes in. UDP has no friendliness
659 * guarantees, and our buffers will fill at some level.
662 * @param target the peer for whom the quota is given
663 * @param quota_in quota for receiving/sending data in bytes per ms
666 udp_plugin_set_receive_quota (void *cls,
667 const struct GNUNET_PeerIdentity *target,
670 return; /* Do nothing */
674 * The exported method. Makes the core api available via a global and
675 * returns the udp transport API.
678 libgnunet_plugin_transport_udp_init (void *cls)
680 unsigned long long mtu;
682 struct GNUNET_TRANSPORT_PluginEnvironment *env = cls;
683 struct GNUNET_TRANSPORT_PluginFunctions *api;
684 struct Plugin *plugin;
685 struct GNUNET_SERVICE_Context *service;
686 unsigned long long aport;
687 unsigned long long bport;
689 service = GNUNET_SERVICE_start ("transport-udp", env->sched, env->cfg);
692 GNUNET_log_from (GNUNET_ERROR_TYPE_WARNING, "udp", _
693 ("Failed to start service for `%s' transport plugin.\n"),
699 GNUNET_CONFIGURATION_get_value_number (env->cfg,
705 GNUNET_CONFIGURATION_get_value_number (env->cfg,
708 &aport)) && (aport > 65535)))
710 GNUNET_log_from (GNUNET_ERROR_TYPE_ERROR,
713 ("Require valid port number for service `%s' in configuration!\n"),
715 GNUNET_SERVICE_stop (service);
723 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO,
725 _("MTU %llu for `%s' is probably too low!\n"), mtu,
728 plugin = GNUNET_malloc (sizeof (struct Plugin));
729 plugin->open_port = bport;
730 plugin->adv_port = aport;
732 plugin->statistics = NULL;
733 api = GNUNET_malloc (sizeof (struct GNUNET_TRANSPORT_PluginFunctions));
736 api->send = &udp_plugin_send;
737 api->disconnect = &udp_disconnect;
738 api->address_pretty_printer = &udp_plugin_address_pretty_printer;
739 api->set_receive_quota = &udp_plugin_set_receive_quota;
740 api->check_address = &udp_check_address;
742 plugin->service = service;
744 /* FIXME: do the two calls below periodically again and
745 not just once (since the info we get might change...) */
746 GNUNET_OS_network_interfaces_list (&process_interfaces, plugin);
747 plugin->hostname_dns = GNUNET_RESOLVER_hostname_resolve (env->sched,
750 HOSTNAME_RESOLVE_TIMEOUT,
751 &process_hostname_ips,
754 udp_sock = udp_transport_server_start (plugin);
756 GNUNET_assert (udp_sock != NULL);
762 libgnunet_plugin_transport_udp_done (void *cls)
764 struct GNUNET_TRANSPORT_PluginFunctions *api = cls;
765 struct Plugin *plugin = api->cls;
767 udp_transport_server_stop (plugin);
768 if (NULL != hostname_dns)
770 GNUNET_RESOLVER_request_cancel (hostname_dns);
773 GNUNET_SERVICE_stop (plugin->service);
775 GNUNET_NETWORK_fdset_destroy (plugin->rs);
776 GNUNET_free (plugin);
781 /* end of plugin_transport_udp.c */