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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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_YES
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);
220 if ((addr == NULL) || (addrlen == 0))
223 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
224 ("udp_plugin_send called without address, returning!\n"));
226 cont (cont_cls, target, GNUNET_OK);
227 return 0; /* Can never send if we don't have an address!! */
230 /* Build the message to be sent */
231 message = GNUNET_malloc (sizeof (struct UDPMessage) + ntohs (msg->size));
232 ssize = sizeof (struct UDPMessage) + ntohs (msg->size);
235 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
236 ("In udp_send, ssize is %d\n"), ssize);
238 message->header.size = htons (ssize);
239 message->header.type = htons (0);
240 memcpy (&message->sender, plugin->env->my_identity,
241 sizeof (struct GNUNET_PeerIdentity));
242 memcpy (&message[1], msg, ntohs (msg->size));
244 /* Actually send the message */
246 GNUNET_NETWORK_socket_sendto (udp_sock, message, ssize,
252 if (sent == GNUNET_SYSERR)
253 cont (cont_cls, target, GNUNET_SYSERR);
257 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
258 ("Sucessfully sent message, calling transmit continuation!\n"));
260 cont (cont_cls, target, GNUNET_OK);
263 GNUNET_free (message);
269 * Add the IP of our network interface to the list of
270 * our external IP addresses.
273 process_interfaces (void *cls,
276 const struct sockaddr *addr, socklen_t addrlen)
278 struct Plugin *plugin = cls;
280 struct sockaddr_in *v4;
281 struct sockaddr_in6 *v6;
283 af = addr->sa_family;
286 v4 = (struct sockaddr_in *) addr;
287 v4->sin_port = htons (plugin->adv_port);
291 GNUNET_assert (af == AF_INET6);
292 v6 = (struct sockaddr_in6 *) addr;
293 v6->sin6_port = htons (plugin->adv_port);
295 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO |
296 GNUNET_ERROR_TYPE_BULK,
297 "udp", _("Found address `%s' (%s)\n"),
298 GNUNET_a2s (addr, addrlen), name);
299 plugin->env->notify_address (plugin->env->cls,
301 addr, addrlen, GNUNET_TIME_UNIT_FOREVER_REL);
308 * Function called by the resolver for each address obtained from DNS
309 * for our own hostname. Add the addresses to the list of our
310 * external IP addresses.
313 * @param addr one of the addresses of the host, NULL for the last address
314 * @param addrlen length of the address
317 process_hostname_ips (void *cls,
318 const struct sockaddr *addr, socklen_t addrlen)
320 struct Plugin *plugin = cls;
324 plugin->hostname_dns = NULL;
327 process_interfaces (plugin, "<hostname>", GNUNET_YES, addr, addrlen);
332 * @param cls the plugin handle
333 * @param tc the scheduling context (for rescheduling this function again)
335 * We have been notified that our writeset has something to read. Presumably
336 * select has been called already, so we can go ahead and start reading from
337 * the socket immediately. Then we check if there is more to be read by
338 * calling select ourselves while there is stuff on the wire. Then reschedule
339 * this function to be called again once more is available.
343 udp_plugin_select (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
345 struct Plugin *plugin = cls;
346 struct GNUNET_TIME_Relative timeout =
347 GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MILLISECONDS, 500);
349 struct UDPMessage *msg;
350 const struct GNUNET_MessageHeader *hdr;
351 struct GNUNET_PeerIdentity *sender;
354 struct sockaddr_storage addr;
359 buflen = GNUNET_NETWORK_socket_recvfrom_amount (udp_sock);
362 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
363 ("we expect to read %u bytes\n"), buflen);
366 if (buflen == GNUNET_NO)
369 buf = GNUNET_malloc (buflen);
370 fromlen = sizeof (addr);
372 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
373 ("src_addr_len is %u\n"), fromlen);
375 memset (&addr, 0, fromlen);
377 GNUNET_NETWORK_socket_recvfrom (udp_sock, buf, buflen,
378 (struct sockaddr *) &addr, &fromlen);
381 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
382 ("socket_recv returned %u, src_addr_len is %u\n"), ret,
391 msg = (struct UDPMessage *) buf;
394 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
395 ("header reports message size of %d\n"),
396 ntohs (msg->header.size));
398 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
399 ("header reports message type of %d\n"),
400 ntohs (msg->header.type));
402 if (ntohs (msg->header.size) < sizeof (struct UDPMessage))
405 GNUNET_NETWORK_fdset_zero (plugin->rs);
406 GNUNET_NETWORK_fdset_set (plugin->rs, udp_sock);
409 hdr = (const struct GNUNET_MessageHeader *) &msg[1];
410 sender = GNUNET_malloc (sizeof (struct GNUNET_PeerIdentity));
411 memcpy (sender, &msg->sender, sizeof (struct GNUNET_PeerIdentity));
414 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
415 ("msg reports message size of %d\n"),
418 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
419 ("msg reports message type of %d\n"),
422 plugin->env->receive (plugin->env->cls,
423 sender, hdr, UDP_DIRECT_DISTANCE, (char *)&addr, fromlen);
425 GNUNET_free (sender);
429 while (GNUNET_NETWORK_socket_select (plugin->rs,
433 && GNUNET_NETWORK_fdset_isset (plugin->rs, udp_sock));
435 plugin->select_task =
436 GNUNET_SCHEDULER_add_select (plugin->env->sched,
437 GNUNET_SCHEDULER_PRIORITY_DEFAULT,
438 GNUNET_SCHEDULER_NO_TASK,
439 GNUNET_TIME_UNIT_FOREVER_REL, plugin->rs,
440 NULL, &udp_plugin_select, plugin);
445 * Create a UDP socket. If possible, use IPv6, otherwise
448 static struct GNUNET_NETWORK_Handle *
449 udp_transport_server_start (void *cls)
451 struct Plugin *plugin = cls;
452 struct GNUNET_NETWORK_Handle *desc;
453 struct sockaddr_in serverAddrv4;
454 struct sockaddr_in6 serverAddrv6;
455 struct sockaddr *serverAddr;
460 GNUNET_CONFIGURATION_get_value_yesno (plugin->env->cfg, "GNUNETD",
463 desc = GNUNET_NETWORK_socket_create (PF_INET6, SOCK_DGRAM, 17);
466 memset (&serverAddrv6, 0, sizeof (serverAddrv6));
467 #if HAVE_SOCKADDR_IN_SIN_LEN
468 serverAddrv6.sin6_len = sizeof (serverAddrv6);
470 serverAddrv6.sin6_family = AF_INET6;
471 serverAddrv6.sin6_addr = in6addr_any;
472 serverAddrv6.sin6_port = htons (plugin->open_port);
473 addrlen = sizeof (serverAddrv6);
474 serverAddr = (struct sockaddr *) &serverAddrv6;
479 desc = GNUNET_NETWORK_socket_create (PF_INET, SOCK_DGRAM, 17);
482 GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "udp", "socket");
487 memset (&serverAddrv4, 0, sizeof (serverAddrv4));
488 #if HAVE_SOCKADDR_IN_SIN_LEN
489 serverAddrv4.sin_len = sizeof (serverAddrv4);
491 serverAddrv4.sin_family = AF_INET;
492 serverAddrv4.sin_addr.s_addr = INADDR_ANY;
493 serverAddrv4.sin_port = htons (plugin->open_port);
494 addrlen = sizeof (serverAddrv4);
495 serverAddr = (struct sockaddr *) &serverAddrv4;
501 GNUNET_assert (GNUNET_NETWORK_socket_bind (desc, serverAddr, addrlen) ==
505 plugin->rs = GNUNET_NETWORK_fdset_create ();
507 GNUNET_NETWORK_fdset_zero (plugin->rs);
508 GNUNET_NETWORK_fdset_set (plugin->rs, desc);
510 plugin->select_task =
511 GNUNET_SCHEDULER_add_select (plugin->env->sched,
512 GNUNET_SCHEDULER_PRIORITY_DEFAULT,
513 GNUNET_SCHEDULER_NO_TASK,
514 GNUNET_TIME_UNIT_FOREVER_REL, plugin->rs,
515 NULL, &udp_plugin_select, plugin);
522 * Check if the given port is plausible (must be either
523 * our listen port or our advertised port). If it is
524 * neither, we return one of these two ports at random.
526 * @return either in_port or a more plausible port
529 check_port (struct Plugin *plugin, uint16_t in_port)
531 if ((in_port == plugin->adv_port) || (in_port == plugin->open_port))
533 return (GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK,
535 ? plugin->open_port : plugin->adv_port;
540 * Another peer has suggested an address for this peer and transport
541 * plugin. Check that this could be a valid address. This function
542 * is not expected to 'validate' the address in the sense of trying to
543 * connect to it but simply to see if the binary format is technically
544 * legal for establishing a connection.
546 * @param addr pointer to the address, may be modified (slightly)
547 * @param addrlen length of addr
548 * @return GNUNET_OK if this is a plausible address for this peer
549 * and transport, GNUNET_SYSERR if not
551 * TODO: perhaps make everything work with sockaddr_storage, it may
552 * be a cleaner way to handle addresses in UDP
555 udp_check_address (void *cls, void *addr, size_t addrlen)
557 struct Plugin *plugin = cls;
558 char buf[sizeof (struct sockaddr_in6)];
560 struct sockaddr_in *v4;
561 struct sockaddr_in6 *v6;
563 if ((addrlen != sizeof (struct sockaddr_in)) &&
564 (addrlen != sizeof (struct sockaddr_in6)))
567 return GNUNET_SYSERR;
569 memcpy (buf, addr, sizeof (struct sockaddr_in6));
570 if (addrlen == sizeof (struct sockaddr_in))
572 v4 = (struct sockaddr_in *) buf;
573 v4->sin_port = htons (check_port (plugin, ntohs (v4->sin_port)));
577 v6 = (struct sockaddr_in6 *) buf;
578 v6->sin6_port = htons (check_port (plugin, ntohs (v6->sin6_port)));
581 GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG,
583 "Informing transport service about my address `%s'.\n",
584 GNUNET_a2s (addr, addrlen));
592 * Append our port and forward the result.
595 append_port (void *cls, const char *hostname)
597 struct PrettyPrinterContext *ppc = cls;
600 if (hostname == NULL)
602 ppc->asc (ppc->asc_cls, NULL);
606 GNUNET_asprintf (&ret, "%s:%d", hostname, ppc->port);
607 ppc->asc (ppc->asc_cls, ret);
613 * Convert the transports address to a nice, human-readable
617 * @param type name of the transport that generated the address
618 * @param addr one of the addresses of the host, NULL for the last address
619 * the specific address format depends on the transport
620 * @param addrlen length of the address
621 * @param numeric should (IP) addresses be displayed in numeric form?
622 * @param timeout after how long should we give up?
623 * @param asc function to call on each string
624 * @param asc_cls closure for asc
627 udp_plugin_address_pretty_printer (void *cls,
632 struct GNUNET_TIME_Relative timeout,
633 GNUNET_TRANSPORT_AddressStringCallback asc,
636 struct Plugin *plugin = cls;
637 const struct sockaddr_in *v4;
638 const struct sockaddr_in6 *v6;
639 struct PrettyPrinterContext *ppc;
641 if ((addrlen != sizeof (struct sockaddr_in)) &&
642 (addrlen != sizeof (struct sockaddr_in6)))
644 /* invalid address */
649 ppc = GNUNET_malloc (sizeof (struct PrettyPrinterContext));
651 ppc->asc_cls = asc_cls;
652 if (addrlen == sizeof (struct sockaddr_in))
654 v4 = (const struct sockaddr_in *) addr;
655 ppc->port = ntohs (v4->sin_port);
659 v6 = (const struct sockaddr_in6 *) addr;
660 ppc->port = ntohs (v6->sin6_port);
663 GNUNET_RESOLVER_hostname_get (plugin->env->sched,
667 !numeric, timeout, &append_port, ppc);
671 * Set a quota for receiving data from the given peer; this is a
672 * per-transport limit. This call has no meaning for UDP, as if
673 * we don't receive data it still comes in. UDP has no friendliness
674 * guarantees, and our buffers will fill at some level.
677 * @param target the peer for whom the quota is given
678 * @param quota_in quota for receiving/sending data in bytes per ms
681 udp_plugin_set_receive_quota (void *cls,
682 const struct GNUNET_PeerIdentity *target,
685 return; /* Do nothing */
689 * The exported method. Makes the core api available via a global and
690 * returns the udp transport API.
693 libgnunet_plugin_transport_udp_init (void *cls)
695 unsigned long long mtu;
697 struct GNUNET_TRANSPORT_PluginEnvironment *env = cls;
698 struct GNUNET_TRANSPORT_PluginFunctions *api;
699 struct Plugin *plugin;
700 struct GNUNET_SERVICE_Context *service;
701 unsigned long long aport;
702 unsigned long long bport;
704 service = GNUNET_SERVICE_start ("transport-udp", env->sched, env->cfg);
707 GNUNET_log_from (GNUNET_ERROR_TYPE_WARNING, "udp", _
708 ("Failed to start service for `%s' transport plugin.\n"),
714 GNUNET_CONFIGURATION_get_value_number (env->cfg,
720 GNUNET_CONFIGURATION_get_value_number (env->cfg,
723 &aport)) && (aport > 65535)))
725 GNUNET_log_from (GNUNET_ERROR_TYPE_ERROR,
728 ("Require valid port number for service `%s' in configuration!\n"),
730 GNUNET_SERVICE_stop (service);
738 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO,
740 _("MTU %llu for `%s' is probably too low!\n"), mtu,
743 plugin = GNUNET_malloc (sizeof (struct Plugin));
744 plugin->open_port = bport;
745 plugin->adv_port = aport;
747 plugin->statistics = NULL;
748 api = GNUNET_malloc (sizeof (struct GNUNET_TRANSPORT_PluginFunctions));
751 api->send = &udp_plugin_send;
752 api->disconnect = &udp_disconnect;
753 api->address_pretty_printer = &udp_plugin_address_pretty_printer;
754 api->set_receive_quota = &udp_plugin_set_receive_quota;
755 api->check_address = &udp_check_address;
757 plugin->service = service;
759 /* FIXME: do the two calls below periodically again and
760 not just once (since the info we get might change...) */
761 GNUNET_OS_network_interfaces_list (&process_interfaces, plugin);
762 plugin->hostname_dns = GNUNET_RESOLVER_hostname_resolve (env->sched,
765 HOSTNAME_RESOLVE_TIMEOUT,
766 &process_hostname_ips,
769 udp_sock = udp_transport_server_start (plugin);
771 GNUNET_assert (udp_sock != NULL);
777 libgnunet_plugin_transport_udp_done (void *cls)
779 struct GNUNET_TRANSPORT_PluginFunctions *api = cls;
780 struct Plugin *plugin = api->cls;
782 udp_transport_server_stop (plugin);
783 if (NULL != hostname_dns)
785 GNUNET_RESOLVER_request_cancel (hostname_dns);
788 GNUNET_SERVICE_stop (plugin->service);
790 GNUNET_NETWORK_fdset_destroy (plugin->rs);
791 GNUNET_free (plugin);
796 /* end of plugin_transport_udp.c */