2 This file is part of GNUnet
3 (C) 2010 Christian Grothoff (and other contributing authors)
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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;
79 struct PrettyPrinterContext
81 GNUNET_TRANSPORT_AddressStringCallback asc;
87 * Encapsulation of all of the state of the plugin.
94 struct GNUNET_TRANSPORT_PluginEnvironment *env;
97 * Handle for the statistics service.
99 struct GNUNET_STATISTICS_Handle *statistics;
102 * Handle to the network service.
104 struct GNUNET_SERVICE_Context *service;
107 * Handle for request of hostname resolution, non-NULL if pending.
109 struct GNUNET_RESOLVER_RequestHandle *hostname_dns;
114 struct GNUNET_NETWORK_FDSet *rs;
117 * ID of task used to update our addresses when one expires.
119 GNUNET_SCHEDULER_TaskIdentifier address_update_task;
124 GNUNET_SCHEDULER_TaskIdentifier select_task;
127 * Port that we are actually listening on.
132 * Port that the user said we would have visible to the
139 /* *********** globals ************* */
142 * the socket that we transmit all data with
144 static struct GNUNET_NETWORK_Handle *udp_sock;
147 * Disconnect from a remote node.
149 * @param cls closure ('struct Plugin'), unused
150 * @param target peer do disconnect
151 * @return GNUNET_OK on success, GNUNET_SYSERR if the operation failed
154 udp_disconnect (void *cls, const struct GNUNET_PeerIdentity *target)
156 /* nothing to do, UDP is stateless */
160 * Shutdown the server process (stop receiving inbound traffic). Maybe
164 udp_transport_server_stop (void *cls)
166 struct Plugin *plugin = cls;
169 GNUNET_assert (udp_sock != NULL);
170 if (plugin->select_task != GNUNET_SCHEDULER_NO_TASK)
172 GNUNET_SCHEDULER_cancel (plugin->env->sched, plugin->select_task);
173 plugin->select_task = GNUNET_SCHEDULER_NO_TASK;
176 ret = GNUNET_NETWORK_socket_close (udp_sock);
177 if (ret != GNUNET_SYSERR)
183 * Function that can be used by the transport service to transmit
184 * a message using the plugin.
187 * @param target who should receive this message (ignored by UDP)
188 * @param msgbuf one or more GNUNET_MessageHeader(s) strung together
189 * @param msgbuf_size the size of the msgbuf to send
190 * @param priority how important is the message (ignored by UDP)
191 * @param timeout when should we time out (give up) if we can not transmit?
192 * @param addr the addr to send the message to, needs to be a sockaddr for us
193 * @param addrlen the len of addr
194 * @param force_address not used, we had better have an address to send to
195 * because we are stateless!!
196 * @param cont continuation to call once the message has
197 * been transmitted (or if the transport is ready
198 * for the next transmission call; or if the
199 * peer disconnected...)
200 * @param cont_cls closure for cont
202 * @return the number of bytes written
206 udp_plugin_send (void *cls,
207 const struct GNUNET_PeerIdentity *target,
210 unsigned int priority,
211 struct GNUNET_TIME_Relative timeout,
215 GNUNET_TRANSPORT_TransmitContinuation cont, void *cont_cls)
217 struct Plugin *plugin = cls;
218 struct UDPMessage *message;
222 GNUNET_assert(udp_sock != NULL);
224 if ((addr == NULL) || (addrlen == 0))
227 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
228 ("udp_plugin_send called without address, returning!\n"));
230 cont (cont_cls, target, GNUNET_OK);
231 return 0; /* Can never send if we don't have an address!! */
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 /* Actually send the message */
250 GNUNET_NETWORK_socket_sendto (udp_sock, message, ssize,
256 if (sent == GNUNET_SYSERR)
257 cont (cont_cls, target, GNUNET_SYSERR);
261 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
262 ("Sucessfully sent message, calling transmit continuation!\n"));
264 cont (cont_cls, target, GNUNET_OK);
267 GNUNET_free (message);
273 * Add the IP of our network interface to the list of
274 * our external IP addresses.
277 process_interfaces (void *cls,
280 const struct sockaddr *addr, socklen_t addrlen)
282 struct Plugin *plugin = cls;
284 struct sockaddr_in *v4;
285 struct sockaddr_in6 *v6;
287 af = addr->sa_family;
290 v4 = (struct sockaddr_in *) addr;
291 v4->sin_port = htons (plugin->adv_port);
295 GNUNET_assert (af == AF_INET6);
296 v6 = (struct sockaddr_in6 *) addr;
297 v6->sin6_port = htons (plugin->adv_port);
299 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO |
300 GNUNET_ERROR_TYPE_BULK,
301 "udp", _("Found address `%s' (%s)\n"),
302 GNUNET_a2s (addr, addrlen), name);
303 plugin->env->notify_address (plugin->env->cls,
305 addr, addrlen, GNUNET_TIME_UNIT_FOREVER_REL);
312 * Function called by the resolver for each address obtained from DNS
313 * for our own hostname. Add the addresses to the list of our
314 * external IP addresses.
317 * @param addr one of the addresses of the host, NULL for the last address
318 * @param addrlen length of the address
321 process_hostname_ips (void *cls,
322 const struct sockaddr *addr, socklen_t addrlen)
324 struct Plugin *plugin = cls;
328 plugin->hostname_dns = NULL;
331 process_interfaces (plugin, "<hostname>", GNUNET_YES, addr, addrlen);
336 * @param cls the plugin handle
337 * @param tc the scheduling context (for rescheduling this function again)
339 * We have been notified that our writeset has something to read. Presumably
340 * select has been called already, so we can go ahead and start reading from
341 * the socket immediately. Then we check if there is more to be read by
342 * calling select ourselves while there is stuff on the wire. Then reschedule
343 * this function to be called again once more is available.
347 udp_plugin_select (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
349 struct Plugin *plugin = cls;
351 struct UDPMessage *msg;
352 struct GNUNET_PeerIdentity *sender;
355 struct sockaddr_storage addr;
361 const struct GNUNET_MessageHeader *currhdr;
364 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
365 ("entered select...\n"));
368 buflen = GNUNET_NETWORK_socket_recvfrom_amount (udp_sock);
371 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
372 ("we expect to read %u bytes\n"), buflen);
375 if (buflen == GNUNET_NO)
378 buf = GNUNET_malloc (buflen);
379 fromlen = sizeof (addr);
381 memset (&addr, 0, fromlen);
383 GNUNET_NETWORK_socket_recvfrom (udp_sock, buf, buflen,
384 (struct sockaddr *) &addr, &fromlen);
387 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
388 ("socket_recv returned %u, src_addr_len is %u\n"), ret,
397 msg = (struct UDPMessage *) buf;
400 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
401 ("header reports message size of %d\n"),
402 ntohs (msg->header.size));
404 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
405 ("header reports message type of %d\n"),
406 ntohs (msg->header.type));
408 if (ntohs (msg->header.size) < sizeof (struct UDPMessage))
411 GNUNET_NETWORK_fdset_zero (plugin->rs);
412 GNUNET_NETWORK_fdset_set (plugin->rs, udp_sock);
415 msgbuf = (char *)&msg[1];
416 sender = GNUNET_malloc (sizeof (struct GNUNET_PeerIdentity));
417 memcpy (sender, &msg->sender, sizeof (struct GNUNET_PeerIdentity));
421 tsize = ntohs (msg->header.size) - sizeof(struct UDPMessage);
423 GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "UDP", _
424 ("offset is %d, tsize is %d (UDPMessage size is %d)\n"),
425 offset, tsize, sizeof(struct UDPMessage));
427 while (offset < tsize)
429 currhdr = (struct GNUNET_MessageHeader *)&msgbuf[offset];
431 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
432 ("processing msg %d: type %d, size %d at offset %d\n"),
433 count, ntohs(currhdr->type), ntohs(currhdr->size), offset);
435 plugin->env->receive (plugin->env->cls,
436 sender, currhdr, UDP_DIRECT_DISTANCE, (char *)&addr, fromlen);
437 offset += ntohs(currhdr->size);
439 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
440 ("offset now %d, tsize %d\n"),
446 GNUNET_free (sender);
449 plugin->select_task =
450 GNUNET_SCHEDULER_add_select (plugin->env->sched,
451 GNUNET_SCHEDULER_PRIORITY_DEFAULT,
452 GNUNET_SCHEDULER_NO_TASK,
453 GNUNET_TIME_UNIT_FOREVER_REL, plugin->rs,
454 NULL, &udp_plugin_select, plugin);
459 * Create a UDP socket. If possible, use IPv6, otherwise
462 static struct GNUNET_NETWORK_Handle *
463 udp_transport_server_start (void *cls)
465 struct Plugin *plugin = cls;
466 struct GNUNET_NETWORK_Handle *desc;
467 struct sockaddr_in serverAddrv4;
468 struct sockaddr_in6 serverAddrv6;
469 struct sockaddr *serverAddr;
474 GNUNET_CONFIGURATION_get_value_yesno (plugin->env->cfg, "GNUNETD",
477 desc = GNUNET_NETWORK_socket_create (PF_INET6, SOCK_DGRAM, 17);
480 memset (&serverAddrv6, 0, sizeof (serverAddrv6));
481 #if HAVE_SOCKADDR_IN_SIN_LEN
482 serverAddrv6.sin6_len = sizeof (serverAddrv6);
484 serverAddrv6.sin6_family = AF_INET6;
485 serverAddrv6.sin6_addr = in6addr_any;
486 serverAddrv6.sin6_port = htons (plugin->open_port);
487 addrlen = sizeof (serverAddrv6);
488 serverAddr = (struct sockaddr *) &serverAddrv6;
493 desc = GNUNET_NETWORK_socket_create (PF_INET, SOCK_DGRAM, 17);
496 GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "udp", "socket");
501 memset (&serverAddrv4, 0, sizeof (serverAddrv4));
502 #if HAVE_SOCKADDR_IN_SIN_LEN
503 serverAddrv4.sin_len = sizeof (serverAddrv4);
505 serverAddrv4.sin_family = AF_INET;
506 serverAddrv4.sin_addr.s_addr = INADDR_ANY;
507 serverAddrv4.sin_port = htons (plugin->open_port);
508 addrlen = sizeof (serverAddrv4);
509 serverAddr = (struct sockaddr *) &serverAddrv4;
515 GNUNET_assert (GNUNET_NETWORK_socket_bind (desc, serverAddr, addrlen) ==
519 plugin->rs = GNUNET_NETWORK_fdset_create ();
521 GNUNET_NETWORK_fdset_zero (plugin->rs);
522 GNUNET_NETWORK_fdset_set (plugin->rs, desc);
524 plugin->select_task =
525 GNUNET_SCHEDULER_add_select (plugin->env->sched,
526 GNUNET_SCHEDULER_PRIORITY_DEFAULT,
527 GNUNET_SCHEDULER_NO_TASK,
528 GNUNET_TIME_UNIT_FOREVER_REL, plugin->rs,
529 NULL, &udp_plugin_select, plugin);
536 * Check if the given port is plausible (must be either
537 * our listen port or our advertised port). If it is
538 * neither, we return one of these two ports at random.
540 * @return either in_port or a more plausible port
543 check_port (struct Plugin *plugin, uint16_t in_port)
545 if ((in_port == plugin->adv_port) || (in_port == plugin->open_port))
547 return (GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK,
549 ? plugin->open_port : plugin->adv_port;
554 * Another peer has suggested an address for this peer and transport
555 * plugin. Check that this could be a valid address. This function
556 * is not expected to 'validate' the address in the sense of trying to
557 * connect to it but simply to see if the binary format is technically
558 * legal for establishing a connection.
560 * @param cls handle to Plugin
561 * @param addr address to check
562 * @param addrlen length of addr
563 * @return GNUNET_OK if this is a plausible address for this peer
564 * and transport, GNUNET_SYSERR if not
566 * TODO: perhaps make everything work with sockaddr_storage, it may
567 * be a cleaner way to handle addresses in UDP
570 udp_check_address (void *cls, void *addr, size_t addrlen)
572 struct Plugin *plugin = cls;
573 char buf[sizeof (struct sockaddr_in6)];
575 struct sockaddr_in *v4;
576 struct sockaddr_in6 *v6;
578 if ((addrlen != sizeof (struct sockaddr_in)) &&
579 (addrlen != sizeof (struct sockaddr_in6)))
582 return GNUNET_SYSERR;
584 memcpy (buf, addr, sizeof (struct sockaddr_in6));
585 if (addrlen == sizeof (struct sockaddr_in))
587 v4 = (struct sockaddr_in *) buf;
588 v4->sin_port = htons (check_port (plugin, ntohs (v4->sin_port)));
592 v6 = (struct sockaddr_in6 *) buf;
593 v6->sin6_port = htons (check_port (plugin, ntohs (v6->sin6_port)));
596 GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG,
598 "Informing transport service about my address `%s'.\n",
599 GNUNET_a2s (addr, addrlen));
607 * Append our port and forward the result.
610 append_port (void *cls, const char *hostname)
612 struct PrettyPrinterContext *ppc = cls;
615 if (hostname == NULL)
617 ppc->asc (ppc->asc_cls, NULL);
621 GNUNET_asprintf (&ret, "%s:%d", hostname, ppc->port);
622 ppc->asc (ppc->asc_cls, ret);
628 * Convert the transports address to a nice, human-readable
632 * @param type name of the transport that generated the address
633 * @param addr one of the addresses of the host, NULL for the last address
634 * the specific address format depends on the transport
635 * @param addrlen length of the address
636 * @param numeric should (IP) addresses be displayed in numeric form?
637 * @param timeout after how long should we give up?
638 * @param asc function to call on each string
639 * @param asc_cls closure for asc
642 udp_plugin_address_pretty_printer (void *cls,
647 struct GNUNET_TIME_Relative timeout,
648 GNUNET_TRANSPORT_AddressStringCallback asc,
651 struct Plugin *plugin = cls;
652 const struct sockaddr_in *v4;
653 const struct sockaddr_in6 *v6;
654 struct PrettyPrinterContext *ppc;
656 if ((addrlen != sizeof (struct sockaddr_in)) &&
657 (addrlen != sizeof (struct sockaddr_in6)))
659 /* invalid address */
664 ppc = GNUNET_malloc (sizeof (struct PrettyPrinterContext));
666 ppc->asc_cls = asc_cls;
667 if (addrlen == sizeof (struct sockaddr_in))
669 v4 = (const struct sockaddr_in *) addr;
670 ppc->port = ntohs (v4->sin_port);
674 v6 = (const struct sockaddr_in6 *) addr;
675 ppc->port = ntohs (v6->sin6_port);
678 GNUNET_RESOLVER_hostname_get (plugin->env->sched,
682 !numeric, timeout, &append_port, ppc);
687 * The exported method. Makes the core api available via a global and
688 * returns the udp transport API.
691 libgnunet_plugin_transport_udp_init (void *cls)
693 unsigned long long mtu;
695 struct GNUNET_TRANSPORT_PluginEnvironment *env = cls;
696 struct GNUNET_TRANSPORT_PluginFunctions *api;
697 struct Plugin *plugin;
698 struct GNUNET_SERVICE_Context *service;
699 unsigned long long aport;
700 unsigned long long bport;
702 service = GNUNET_SERVICE_start ("transport-udp", env->sched, env->cfg);
705 GNUNET_log_from (GNUNET_ERROR_TYPE_WARNING, "udp", _
706 ("Failed to start service for `%s' transport plugin.\n"),
712 GNUNET_CONFIGURATION_get_value_number (env->cfg,
718 GNUNET_CONFIGURATION_get_value_number (env->cfg,
721 &aport)) && (aport > 65535)))
723 GNUNET_log_from (GNUNET_ERROR_TYPE_ERROR,
726 ("Require valid port number for service `%s' in configuration!\n"),
728 GNUNET_SERVICE_stop (service);
736 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO,
738 _("MTU %llu for `%s' is probably too low!\n"), mtu,
741 plugin = GNUNET_malloc (sizeof (struct Plugin));
742 plugin->open_port = bport;
743 plugin->adv_port = aport;
745 plugin->statistics = NULL;
746 api = GNUNET_malloc (sizeof (struct GNUNET_TRANSPORT_PluginFunctions));
749 api->send = &udp_plugin_send;
750 api->disconnect = &udp_disconnect;
751 api->address_pretty_printer = &udp_plugin_address_pretty_printer;
752 api->check_address = &udp_check_address;
754 plugin->service = service;
756 /* FIXME: do the two calls below periodically again and
757 not just once (since the info we get might change...) */
758 GNUNET_OS_network_interfaces_list (&process_interfaces, plugin);
759 plugin->hostname_dns = GNUNET_RESOLVER_hostname_resolve (env->sched,
762 HOSTNAME_RESOLVE_TIMEOUT,
763 &process_hostname_ips,
766 udp_sock = udp_transport_server_start (plugin);
768 GNUNET_assert (udp_sock != NULL);
774 libgnunet_plugin_transport_udp_done (void *cls)
776 struct GNUNET_TRANSPORT_PluginFunctions *api = cls;
777 struct Plugin *plugin = api->cls;
779 udp_transport_server_stop (plugin);
780 if (NULL != hostname_dns)
782 GNUNET_RESOLVER_request_cancel (hostname_dns);
785 GNUNET_SERVICE_stop (plugin->service);
787 GNUNET_NETWORK_fdset_destroy (plugin->rs);
788 GNUNET_free (plugin);
793 /* end of plugin_transport_udp.c */