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
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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 * How long until we give up on transmitting the welcome message?
53 #define HOSTNAME_RESOLVE_TIMEOUT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 5)
57 * Message-Packet header.
62 * size of the message, in bytes, including this header.
64 struct GNUNET_MessageHeader header;
67 * What is the identity of the sender (GNUNET_hash of public key)
69 struct GNUNET_PeerIdentity sender;
74 struct PrettyPrinterContext
76 GNUNET_TRANSPORT_AddressStringCallback asc;
82 * Encapsulation of all of the state of the plugin.
89 struct GNUNET_TRANSPORT_PluginEnvironment *env;
92 * Handle for the statistics service.
94 struct GNUNET_STATISTICS_Handle *statistics;
97 * Handle to the network service.
99 struct GNUNET_SERVICE_Context *service;
102 * Handle for request of hostname resolution, non-NULL if pending.
104 struct GNUNET_RESOLVER_RequestHandle *hostname_dns;
109 struct GNUNET_NETWORK_FDSet *rs;
112 * ID of task used to update our addresses when one expires.
114 GNUNET_SCHEDULER_TaskIdentifier address_update_task;
119 GNUNET_SCHEDULER_TaskIdentifier select_task;
122 * Port that we are actually listening on.
127 * Port that the user said we would have visible to the
134 /* *********** globals ************* */
137 * the socket that we transmit all data with
139 static struct GNUNET_NETWORK_Handle *udp_sock;
142 * Disconnect from a remote node.
144 * @param cls closure ('struct Plugin'), unused
145 * @param target peer do disconnect
146 * @return GNUNET_OK on success, GNUNET_SYSERR if the operation failed
149 udp_disconnect (void *cls, const struct GNUNET_PeerIdentity *target)
151 /* nothing to do, UDP is stateless */
155 * Shutdown the server process (stop receiving inbound traffic). Maybe
159 udp_transport_server_stop (void *cls)
161 struct Plugin *plugin = cls;
164 GNUNET_assert (udp_sock != NULL);
165 if (plugin->select_task != GNUNET_SCHEDULER_NO_TASK)
167 GNUNET_SCHEDULER_cancel (plugin->env->sched, plugin->select_task);
168 plugin->select_task = GNUNET_SCHEDULER_NO_TASK;
171 ret = GNUNET_NETWORK_socket_close (udp_sock);
172 if (ret != GNUNET_SYSERR)
178 * Function that can be used by the transport service to transmit
179 * a message using the plugin.
182 * @param target who should receive this message (ignored by UDP)
183 * @param msgbuf one or more GNUNET_MessageHeader(s) strung together
184 * @param msgbuf_size the size of the msgbuf to send
185 * @param priority how important is the message (ignored by UDP)
186 * @param timeout when should we time out (give up) if we can not transmit?
187 * @param session which session must be used (always NULL for UDP)
188 * @param addr the addr to send the message to, needs to be a sockaddr for us
189 * @param addrlen the len of addr
190 * @param force_address GNUNET_YES if the plugin MUST use the given address,
191 * GNUNET_NO means the plugin may use any other address and
192 * GNUNET_SYSERR means that only reliable existing
193 * bi-directional connections should be used (regardless
195 * @param cont continuation to call once the message has
196 * been transmitted (or if the transport is ready
197 * for the next transmission call; or if the
198 * peer disconnected...)
199 * @param cont_cls closure for cont
201 * @return the number of bytes written, -1 on error (in this case, cont is not called)
204 udp_plugin_send (void *cls,
205 const struct GNUNET_PeerIdentity *target,
208 unsigned int priority,
209 struct GNUNET_TIME_Relative timeout,
210 struct Session *session,
214 GNUNET_TRANSPORT_TransmitContinuation cont, void *cont_cls)
216 struct Plugin *plugin = cls;
217 struct UDPMessage *message;
221 GNUNET_assert (NULL == session);
222 GNUNET_assert(udp_sock != NULL);
223 if ( (addr == NULL) || (addrlen == 0) )
226 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
227 ("udp_plugin_send called without address, returning!\n"));
229 return -1; /* Can never send if we don't have an address!! */
231 if (force_address == GNUNET_SYSERR)
232 return -1; /* never reliable */
234 /* Build the message to be sent */
235 message = GNUNET_malloc (sizeof (struct UDPMessage) + msgbuf_size);
236 ssize = sizeof (struct UDPMessage) + msgbuf_size;
239 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
240 ("In udp_send, ssize is %d, sending message to %s\n"), ssize, GNUNET_a2s((const struct sockaddr *)addr, addrlen));
242 message->header.size = htons (ssize);
243 message->header.type = htons (0);
244 memcpy (&message->sender, plugin->env->my_identity,
245 sizeof (struct GNUNET_PeerIdentity));
246 memcpy (&message[1], msgbuf, msgbuf_size);
248 GNUNET_NETWORK_socket_sendto (udp_sock, message, ssize,
251 if ( (cont != NULL) &&
253 cont (cont_cls, target, GNUNET_OK);
254 GNUNET_free (message);
260 * Add the IP of our network interface to the list of
261 * our external IP addresses.
264 process_interfaces (void *cls,
267 const struct sockaddr *addr, socklen_t addrlen)
269 struct Plugin *plugin = cls;
271 struct sockaddr_in *v4;
272 struct sockaddr_in6 *v6;
274 af = addr->sa_family;
277 v4 = (struct sockaddr_in *) addr;
278 v4->sin_port = htons (plugin->adv_port);
282 GNUNET_assert (af == AF_INET6);
283 v6 = (struct sockaddr_in6 *) addr;
284 v6->sin6_port = htons (plugin->adv_port);
286 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO |
287 GNUNET_ERROR_TYPE_BULK,
288 "udp", _("Found address `%s' (%s)\n"),
289 GNUNET_a2s (addr, addrlen), name);
290 plugin->env->notify_address (plugin->env->cls,
292 addr, addrlen, GNUNET_TIME_UNIT_FOREVER_REL);
299 * Function called by the resolver for each address obtained from DNS
300 * for our own hostname. Add the addresses to the list of our
301 * external IP addresses.
304 * @param addr one of the addresses of the host, NULL for the last address
305 * @param addrlen length of the address
308 process_hostname_ips (void *cls,
309 const struct sockaddr *addr, socklen_t addrlen)
311 struct Plugin *plugin = cls;
315 plugin->hostname_dns = NULL;
318 process_interfaces (plugin, "<hostname>", GNUNET_YES, addr, addrlen);
323 * @param cls the plugin handle
324 * @param tc the scheduling context (for rescheduling this function again)
326 * We have been notified that our writeset has something to read. Presumably
327 * select has been called already, so we can go ahead and start reading from
328 * the socket immediately. Then we check if there is more to be read by
329 * calling select ourselves while there is stuff on the wire. Then reschedule
330 * this function to be called again once more is available.
334 udp_plugin_select (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
336 struct Plugin *plugin = cls;
338 struct UDPMessage *msg;
339 struct GNUNET_PeerIdentity *sender;
342 struct sockaddr_storage addr;
348 const struct GNUNET_MessageHeader *currhdr;
351 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
352 ("entered select...\n"));
355 buflen = GNUNET_NETWORK_socket_recvfrom_amount (udp_sock);
358 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
359 ("we expect to read %u bytes\n"), buflen);
362 if (buflen == GNUNET_NO)
365 buf = GNUNET_malloc (buflen);
366 fromlen = sizeof (addr);
368 memset (&addr, 0, fromlen);
370 GNUNET_NETWORK_socket_recvfrom (udp_sock, buf, buflen,
371 (struct sockaddr *) &addr, &fromlen);
374 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
375 ("socket_recv returned %u, src_addr_len is %u\n"), ret,
384 msg = (struct UDPMessage *) buf;
387 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
388 ("header reports message size of %d\n"),
389 ntohs (msg->header.size));
391 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
392 ("header reports message type of %d\n"),
393 ntohs (msg->header.type));
395 if (ntohs (msg->header.size) < sizeof (struct UDPMessage))
398 GNUNET_NETWORK_fdset_zero (plugin->rs);
399 GNUNET_NETWORK_fdset_set (plugin->rs, udp_sock);
402 msgbuf = (char *)&msg[1];
403 sender = GNUNET_malloc (sizeof (struct GNUNET_PeerIdentity));
404 memcpy (sender, &msg->sender, sizeof (struct GNUNET_PeerIdentity));
408 tsize = ntohs (msg->header.size) - sizeof(struct UDPMessage);
410 GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "UDP", _
411 ("offset is %d, tsize is %d (UDPMessage size is %d)\n"),
412 offset, tsize, sizeof(struct UDPMessage));
414 while (offset < tsize)
416 currhdr = (struct GNUNET_MessageHeader *)&msgbuf[offset];
418 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
419 ("processing msg %d: type %d, size %d at offset %d\n"),
420 count, ntohs(currhdr->type), ntohs(currhdr->size), offset);
422 plugin->env->receive (plugin->env->cls,
423 sender, currhdr, UDP_DIRECT_DISTANCE,
424 NULL, (const char *)&addr, fromlen);
425 offset += ntohs(currhdr->size);
427 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
428 ("offset now %d, tsize %d\n"),
434 GNUNET_free (sender);
437 plugin->select_task =
438 GNUNET_SCHEDULER_add_select (plugin->env->sched,
439 GNUNET_SCHEDULER_PRIORITY_DEFAULT,
440 GNUNET_SCHEDULER_NO_TASK,
441 GNUNET_TIME_UNIT_FOREVER_REL, plugin->rs,
442 NULL, &udp_plugin_select, plugin);
447 * Create a UDP socket. If possible, use IPv6, otherwise
450 static struct GNUNET_NETWORK_Handle *
451 udp_transport_server_start (void *cls)
453 struct Plugin *plugin = cls;
454 struct GNUNET_NETWORK_Handle *desc;
455 struct sockaddr_in serverAddrv4;
456 struct sockaddr_in6 serverAddrv6;
457 struct sockaddr *serverAddr;
462 GNUNET_CONFIGURATION_get_value_yesno (plugin->env->cfg, "GNUNETD",
465 desc = GNUNET_NETWORK_socket_create (PF_INET6, SOCK_DGRAM, 17);
468 memset (&serverAddrv6, 0, sizeof (serverAddrv6));
469 #if HAVE_SOCKADDR_IN_SIN_LEN
470 serverAddrv6.sin6_len = sizeof (serverAddrv6);
472 serverAddrv6.sin6_family = AF_INET6;
473 serverAddrv6.sin6_addr = in6addr_any;
474 serverAddrv6.sin6_port = htons (plugin->open_port);
475 addrlen = sizeof (serverAddrv6);
476 serverAddr = (struct sockaddr *) &serverAddrv6;
481 desc = GNUNET_NETWORK_socket_create (PF_INET, SOCK_DGRAM, 17);
484 GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "udp", "socket");
489 memset (&serverAddrv4, 0, sizeof (serverAddrv4));
490 #if HAVE_SOCKADDR_IN_SIN_LEN
491 serverAddrv4.sin_len = sizeof (serverAddrv4);
493 serverAddrv4.sin_family = AF_INET;
494 serverAddrv4.sin_addr.s_addr = INADDR_ANY;
495 serverAddrv4.sin_port = htons (plugin->open_port);
496 addrlen = sizeof (serverAddrv4);
497 serverAddr = (struct sockaddr *) &serverAddrv4;
503 GNUNET_assert (GNUNET_NETWORK_socket_bind (desc, serverAddr, addrlen) ==
507 plugin->rs = GNUNET_NETWORK_fdset_create ();
509 GNUNET_NETWORK_fdset_zero (plugin->rs);
510 GNUNET_NETWORK_fdset_set (plugin->rs, desc);
512 plugin->select_task =
513 GNUNET_SCHEDULER_add_select (plugin->env->sched,
514 GNUNET_SCHEDULER_PRIORITY_DEFAULT,
515 GNUNET_SCHEDULER_NO_TASK,
516 GNUNET_TIME_UNIT_FOREVER_REL, plugin->rs,
517 NULL, &udp_plugin_select, plugin);
524 * Check if the given port is plausible (must be either
525 * our listen port or our advertised port). If it is
526 * neither, we return one of these two ports at random.
528 * @return either in_port or a more plausible port
531 check_port (struct Plugin *plugin, uint16_t in_port)
533 if ((in_port == plugin->adv_port) || (in_port == plugin->open_port))
535 return (GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK,
537 ? plugin->open_port : plugin->adv_port;
542 * Another peer has suggested an address for this peer and transport
543 * plugin. Check that this could be a valid address. This function
544 * is not expected to 'validate' the address in the sense of trying to
545 * connect to it but simply to see if the binary format is technically
546 * legal for establishing a connection.
548 * @param cls handle to Plugin
549 * @param addr address to check
550 * @param addrlen length of addr
551 * @return GNUNET_OK if this is a plausible address for this peer
552 * and transport, GNUNET_SYSERR if not
554 * TODO: perhaps make everything work with sockaddr_storage, it may
555 * be a cleaner way to handle addresses in UDP
558 udp_check_address (void *cls, void *addr, size_t addrlen)
560 struct Plugin *plugin = cls;
561 char buf[sizeof (struct sockaddr_in6)];
563 struct sockaddr_in *v4;
564 struct sockaddr_in6 *v6;
566 if ((addrlen != sizeof (struct sockaddr_in)) &&
567 (addrlen != sizeof (struct sockaddr_in6)))
570 return GNUNET_SYSERR;
572 memcpy (buf, addr, sizeof (struct sockaddr_in6));
573 if (addrlen == sizeof (struct sockaddr_in))
575 v4 = (struct sockaddr_in *) buf;
576 v4->sin_port = htons (check_port (plugin, ntohs (v4->sin_port)));
580 v6 = (struct sockaddr_in6 *) buf;
581 v6->sin6_port = htons (check_port (plugin, ntohs (v6->sin6_port)));
584 GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG,
586 "Informing transport service about my address `%s'.\n",
587 GNUNET_a2s (addr, addrlen));
595 * Append our port and forward the result.
598 append_port (void *cls, const char *hostname)
600 struct PrettyPrinterContext *ppc = cls;
603 if (hostname == NULL)
605 ppc->asc (ppc->asc_cls, NULL);
609 GNUNET_asprintf (&ret, "%s:%d", hostname, ppc->port);
610 ppc->asc (ppc->asc_cls, ret);
616 * Convert the transports address to a nice, human-readable
620 * @param type name of the transport that generated the address
621 * @param addr one of the addresses of the host, NULL for the last address
622 * the specific address format depends on the transport
623 * @param addrlen length of the address
624 * @param numeric should (IP) addresses be displayed in numeric form?
625 * @param timeout after how long should we give up?
626 * @param asc function to call on each string
627 * @param asc_cls closure for asc
630 udp_plugin_address_pretty_printer (void *cls,
635 struct GNUNET_TIME_Relative timeout,
636 GNUNET_TRANSPORT_AddressStringCallback asc,
639 struct Plugin *plugin = cls;
640 const struct sockaddr_in *v4;
641 const struct sockaddr_in6 *v6;
642 struct PrettyPrinterContext *ppc;
644 if ((addrlen != sizeof (struct sockaddr_in)) &&
645 (addrlen != sizeof (struct sockaddr_in6)))
647 /* invalid address */
652 ppc = GNUNET_malloc (sizeof (struct PrettyPrinterContext));
654 ppc->asc_cls = asc_cls;
655 if (addrlen == sizeof (struct sockaddr_in))
657 v4 = (const struct sockaddr_in *) addr;
658 ppc->port = ntohs (v4->sin_port);
662 v6 = (const struct sockaddr_in6 *) addr;
663 ppc->port = ntohs (v6->sin6_port);
666 GNUNET_RESOLVER_hostname_get (plugin->env->sched,
670 !numeric, timeout, &append_port, ppc);
675 * The exported method. Makes the core api available via a global and
676 * returns the udp transport API.
679 libgnunet_plugin_transport_udp_init (void *cls)
681 struct GNUNET_TRANSPORT_PluginEnvironment *env = cls;
682 struct GNUNET_TRANSPORT_PluginFunctions *api;
683 struct Plugin *plugin;
684 struct GNUNET_SERVICE_Context *service;
685 unsigned long long aport;
686 unsigned long long bport;
687 unsigned long long mtu;
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->check_address = &udp_check_address;
741 plugin->service = service;
743 /* FIXME: do the two calls below periodically again and
744 not just once (since the info we get might change...) */
745 GNUNET_OS_network_interfaces_list (&process_interfaces, plugin);
746 plugin->hostname_dns = GNUNET_RESOLVER_hostname_resolve (env->sched,
749 HOSTNAME_RESOLVE_TIMEOUT,
750 &process_hostname_ips,
753 udp_sock = udp_transport_server_start (plugin);
755 GNUNET_assert (udp_sock != NULL);
761 libgnunet_plugin_transport_udp_done (void *cls)
763 struct GNUNET_TRANSPORT_PluginFunctions *api = cls;
764 struct Plugin *plugin = api->cls;
766 udp_transport_server_stop (plugin);
767 if (NULL != plugin->hostname_dns)
769 GNUNET_RESOLVER_request_cancel (plugin->hostname_dns);
770 plugin->hostname_dns = NULL;
772 GNUNET_SERVICE_stop (plugin->service);
774 GNUNET_NETWORK_fdset_destroy (plugin->rs);
775 GNUNET_free (plugin);
780 /* end of plugin_transport_udp.c */