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
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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 * The default maximum size of each outbound UDP message,
47 * optimal value for Ethernet (10 or 100 MBit).
49 #define MESSAGE_SIZE 1472
52 * Handle for request of hostname resolution, non-NULL if pending.
54 static struct GNUNET_RESOLVER_RequestHandle *hostname_dns;
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;
73 /* Forward definition */
77 * Session handle for UDP connections.
83 * Stored in a linked list.
88 * Pointer to the global plugin struct.
90 struct Plugin *plugin;
93 * To whom are we talking to (set to our identity
95 struct GNUNET_PeerIdentity target;
98 * Address of the other peer if WE initiated the connection
99 * (and hence can be sure what it is), otherwise NULL.
104 * Length of connect_addr, can be 0.
109 * Random challenge number for validation
114 * Have we received validation (performed ping/pong) from this peer?
116 unsigned int validated;
121 * Encapsulation of all of the state of the plugin.
128 struct GNUNET_TRANSPORT_PluginEnvironment *env;
131 * List of open TCP sessions.
133 struct Session *sessions;
136 * Handle for the statistics service.
138 struct GNUNET_STATISTICS_Handle *statistics;
141 * Handle to the network service.
143 struct GNUNET_SERVICE_Context *service;
146 * ID of task used to update our addresses when one expires.
148 GNUNET_SCHEDULER_TaskIdentifier address_update_task;
153 GNUNET_SCHEDULER_TaskIdentifier select_task;
156 * Port that we are actually listening on.
161 * Port that the user said we would have visible to the
169 struct GNUNET_NETWORK_FDSet *rs;
174 * Message used to ask a peer to validate receipt (to check an address
175 * from a HELLO). Followed by the address used. Note that the
176 * recipients response does not affirm that he has this address,
177 * only that he got the challenge message.
179 struct UDPPingMessage
183 * Type will be GNUNET_MESSAGE_TYPE_TRANSPORT_TCP_PING
185 struct GNUNET_MessageHeader header;
188 * Random challenge number (in network byte order).
190 uint32_t challenge GNUNET_PACKED;
198 * Message used to validate a HELLO. The challenge is included in the
199 * confirmation to make matching of replies to requests possible. The
200 * signature signs the original challenge number, our public key, the
201 * sender's address (so that the sender can check that the address we
202 * saw is plausible for him and possibly detect a MiM attack) and a
203 * timestamp (to limit replay).<p>
205 * This message is followed by the address of the
206 * client that we are observing (which is part of what
209 struct UDPPongMessage
212 * Type will be GNUNET_MESSAGE_TYPE_TRANSPORT_TCP_PONG
214 struct GNUNET_MessageHeader header;
217 * Random challenge number (in network byte order).
219 uint32_t challenge GNUNET_PACKED;
221 /* Length of addr, appended to end of message */
222 unsigned int addrlen;
225 /* *********** globals ************* */
228 * the socket that we transmit all data with
230 static struct GNUNET_NETWORK_Handle *udp_sock;
234 * A (core) Session is to be associated with a transport session. The
235 * transport service may want to know in order to call back on the
236 * core if the connection is being closed.
238 * @param session the session handle passed along
239 * from the call to receive that was made by the transport
241 * @return GNUNET_OK if the session could be associated,
242 * GNUNET_SYSERR if not.
245 udp_associate (struct Session *session)
247 return GNUNET_SYSERR; /* UDP connections can never be associated */
251 * Disconnect from a remote node.
253 * @param tsession the session that is closed
254 * @return GNUNET_OK on success, GNUNET_SYSERR if the operation failed
257 udp_disconnect (void *cls, const struct GNUNET_PeerIdentity *target)
263 * Shutdown the server process (stop receiving inbound traffic). Maybe
267 udp_transport_server_stop (void *cls)
269 struct Plugin *plugin = cls;
270 GNUNET_assert (udp_sock != NULL);
271 if (plugin->select_task != GNUNET_SCHEDULER_NO_TASK)
273 GNUNET_SCHEDULER_cancel (plugin->env->sched, plugin->select_task);
274 plugin->select_task = GNUNET_SCHEDULER_NO_TASK;
277 GNUNET_NETWORK_socket_close (udp_sock);
282 static struct Session *
283 find_session (void *cls, struct Session *session_list,
284 const struct GNUNET_PeerIdentity *peer)
286 struct Plugin *plugin = cls;
292 if (memcmp (peer, &pos->target, sizeof (struct GNUNET_PeerIdentity)) ==
302 * Function that can be used by the transport service to transmit
303 * a message using the plugin.
306 * @param service_context value passed to the transport-service
307 * to identify the neighbour
308 * @param target who should receive this message
309 * @param priority how important is the message
310 * @param msg the message to transmit
311 * @param timeout when should we time out (give up) if we can not transmit?
312 * @param cont continuation to call once the message has
313 * been transmitted (or if the transport is ready
314 * for the next transmission call; or if the
315 * peer disconnected...)
316 * @param cont_cls closure for cont
319 udp_plugin_send (void *cls,
320 const struct GNUNET_PeerIdentity *target,
321 unsigned int priority,
322 const struct GNUNET_MessageHeader *msg,
323 struct GNUNET_TIME_Relative timeout,
324 GNUNET_TRANSPORT_TransmitContinuation cont, void *cont_cls)
326 struct Plugin *plugin = cls;
327 struct Session *session;
328 struct UDPMessage *message;
332 session = find_session (plugin, plugin->sessions, target);
334 if ((session == NULL) || (udp_sock == NULL))
337 /* Build the message to be sent */
338 message = GNUNET_malloc (sizeof (struct UDPMessage) + ntohs (msg->size));
339 ssize = sizeof (struct UDPMessage) + ntohs (msg->size);
342 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
343 ("In udp_send, ssize is %d\n"), ssize);
345 message->header.size = htons (ssize);
346 message->header.type = htons (0);
347 memcpy (&message->sender, plugin->env->my_identity,
348 sizeof (struct GNUNET_PeerIdentity));
349 memcpy (&message[1], msg, ntohs (msg->size));
351 /* Actually send the message */
353 GNUNET_NETWORK_socket_sendto (udp_sock, message, ssize,
354 session->connect_addr,
355 session->connect_alen);
359 if (sent == GNUNET_SYSERR)
360 cont (cont_cls, target, GNUNET_SYSERR);
362 cont (cont_cls, target, GNUNET_OK);
364 GNUNET_free(message);
369 * We've received a PING from this peer via UDP.
370 * Send back our PONG.
373 * @param sender the Identity of the sender
374 * @param message the actual message
377 handle_udp_ping (void *cls,
378 struct GNUNET_PeerIdentity *sender,
379 struct sockaddr_storage *addr, size_t addrlen,
380 const struct GNUNET_MessageHeader *message)
382 struct Plugin *plugin = cls;
383 struct Session *head = plugin->sessions;
384 const struct UDPPingMessage *ping = (const struct UDPPingMessage *) message;
385 struct UDPPongMessage *pong;
386 struct Session *found;
389 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
390 ("handling ping, challenge is %d\n"),
391 ntohs (ping->challenge));
393 found = find_session (plugin, head, sender);
396 pong = GNUNET_malloc (sizeof (struct UDPPongMessage) + addrlen);
397 pong->header.type = htons (GNUNET_MESSAGE_TYPE_TRANSPORT_UDP_PONG);
398 pong->header.size = htons (sizeof (struct UDPPongMessage) + addrlen);
399 pong->challenge = ping->challenge;
400 memcpy (&pong[1], addr, addrlen);
401 pong->addrlen = htons (addrlen);
403 udp_plugin_send (plugin, sender, GNUNET_SCHEDULER_PRIORITY_DEFAULT,
405 GNUNET_TIME_relative_multiply
406 (GNUNET_TIME_UNIT_SECONDS, 30), NULL, NULL);
415 * We've received a PONG from this peer via UDP.
416 * Great. Call validate func if we haven't already
420 * @param client identification of the client
421 * @param message the actual message
424 handle_udp_pong (void *cls,
425 struct GNUNET_PeerIdentity *sender,
426 const struct GNUNET_MessageHeader *message)
428 struct Plugin *plugin = cls;
429 const struct UDPPongMessage *pong = (struct UDPPongMessage *) message;
430 struct Session *found;
431 unsigned int addr_len;
432 struct sockaddr_storage addr;
435 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _("handling pong\n"));
437 found = find_session (plugin, plugin->sessions, sender);
439 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
440 ("found->challenge %d, pong->challenge %d\n"),
441 found->challenge, ntohs (pong->challenge));
443 if ((found != NULL) && (found->challenge == ntohs (pong->challenge)))
445 found->validated = GNUNET_YES;
446 addr_len = ntohs (pong->addrlen);
448 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
449 ("found associated ping, addr is %u bytes\n"),
452 memcpy (&addr, &pong[1], addr_len);
453 plugin->env->notify_validation (plugin->env->cls, "udp", sender,
454 ntohs (pong->challenge),
461 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
462 ("Session not found!\n"));
469 udp_plugin_select (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
471 struct Plugin *plugin = cls;
472 struct GNUNET_TIME_Relative timeout =
473 GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MILLISECONDS, 500);
475 struct UDPMessage *msg;
476 const struct GNUNET_MessageHeader *hdr;
477 struct GNUNET_PeerIdentity *sender;
480 struct sockaddr_storage addr;
485 buflen = GNUNET_NETWORK_socket_recvfrom_amount (udp_sock);
488 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
489 ("we expect to read %u bytes\n"), buflen);
492 if (buflen == GNUNET_NO)
495 buf = GNUNET_malloc (buflen);
496 fromlen = sizeof (addr);
499 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
500 ("src_addr_len is %u\n"), fromlen);
503 memset (&addr, 0, fromlen);
505 GNUNET_NETWORK_socket_recvfrom (udp_sock, buf, buflen,
506 (struct sockaddr *) &addr, &fromlen);
509 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
510 ("socket_recv returned %u, src_addr_len is %u\n"), ret,
520 msg = (struct UDPMessage *) buf;
523 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
524 ("header reports message size of %d\n"),
525 ntohs (msg->header.size));
527 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
528 ("header reports message type of %d\n"),
529 ntohs (msg->header.type));
531 /*if (ntohs(hdr->size) < sizeof(struct UDPMessage))
534 GNUNET_NETWORK_fdset_zero(plugin->rs);
535 GNUNET_NETWORK_fdset_set(plugin->rs, udp_sock);
538 hdr = (const struct GNUNET_MessageHeader *) &msg[1];
539 sender = GNUNET_malloc (sizeof (struct GNUNET_PeerIdentity));
540 memcpy (sender, &msg->sender, sizeof (struct GNUNET_PeerIdentity));
543 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
544 ("msg reports message size of %d\n"),
547 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
548 ("msg reports message type of %d\n"),
552 if (ntohs (hdr->type) == GNUNET_MESSAGE_TYPE_TRANSPORT_UDP_PING)
554 handle_udp_ping (plugin, sender, &addr, fromlen, hdr);
557 if (ntohs (hdr->type) == GNUNET_MESSAGE_TYPE_TRANSPORT_UDP_PONG)
559 handle_udp_pong (plugin, sender, hdr);
565 while (GNUNET_NETWORK_socket_select (plugin->rs,
569 && GNUNET_NETWORK_fdset_isset (plugin->rs, udp_sock));
571 plugin->select_task =
572 GNUNET_SCHEDULER_add_select (plugin->env->sched,
573 GNUNET_SCHEDULER_PRIORITY_DEFAULT,
574 GNUNET_SCHEDULER_NO_TASK,
575 GNUNET_TIME_UNIT_FOREVER_REL, plugin->rs,
576 NULL, &udp_plugin_select, plugin);
581 * Create a UDP socket. If possible, use IPv6, otherwise
584 static struct GNUNET_NETWORK_Handle *
585 udp_transport_server_start (void *cls)
587 struct Plugin *plugin = cls;
588 struct GNUNET_NETWORK_Handle *desc;
589 struct sockaddr_in serverAddrv4;
590 struct sockaddr_in6 serverAddrv6;
591 struct sockaddr *serverAddr;
596 GNUNET_CONFIGURATION_get_value_yesno (plugin->env->cfg, "GNUNETD",
599 desc = GNUNET_NETWORK_socket_create (PF_INET6, SOCK_DGRAM, 17);
602 memset (&serverAddrv6, 0, sizeof (serverAddrv6));
603 #if HAVE_SOCKADDR_IN_SIN_LEN
604 serverAddrv6.sin6_len = sizeof (serverAddrv6);
606 serverAddrv6.sin6_family = AF_INET6;
607 serverAddrv6.sin6_addr = in6addr_any;
608 serverAddrv6.sin6_port = htons (plugin->open_port);
609 addrlen = sizeof (serverAddrv6);
610 serverAddr = (struct sockaddr *) &serverAddrv6;
615 desc = GNUNET_NETWORK_socket_create (PF_INET, SOCK_DGRAM, 17);
618 GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "udp", "socket");
623 memset (&serverAddrv4, 0, sizeof (serverAddrv4));
624 #if HAVE_SOCKADDR_IN_SIN_LEN
625 serverAddrv4.sin_len = sizeof (serverAddrv4);
627 serverAddrv4.sin_family = AF_INET;
628 serverAddrv4.sin_addr.s_addr = INADDR_ANY;
629 serverAddrv4.sin_port = htons (plugin->open_port);
630 addrlen = sizeof (serverAddrv4);
631 serverAddr = (struct sockaddr *) &serverAddrv4;
637 GNUNET_assert (GNUNET_NETWORK_socket_bind (desc, serverAddr, addrlen) ==
641 plugin->rs = GNUNET_NETWORK_fdset_create ();
643 GNUNET_NETWORK_fdset_zero (plugin->rs);
644 GNUNET_NETWORK_fdset_set (plugin->rs, desc);
646 plugin->select_task =
647 GNUNET_SCHEDULER_add_select (plugin->env->sched,
648 GNUNET_SCHEDULER_PRIORITY_DEFAULT,
649 GNUNET_SCHEDULER_NO_TASK,
650 GNUNET_TIME_UNIT_FOREVER_REL, plugin->rs,
651 NULL, &udp_plugin_select, plugin);
657 * Function that can be used by the transport service to validate that
658 * another peer is reachable at a particular address (even if we
659 * already have a connection to this peer, this function is required
660 * to establish a new one).
663 * @param target who should receive this message
664 * @param challenge challenge code to use
665 * @param addrlen length of the address
666 * @param addr the address
667 * @param timeout how long should we try to transmit these?
668 * @return GNUNET_OK if the transmission has been scheduled
671 udp_plugin_validate (void *cls,
672 const struct GNUNET_PeerIdentity *target,
674 struct GNUNET_TIME_Relative timeout,
675 const void *addr, size_t addrlen)
677 struct Plugin *plugin = cls;
678 struct Session *new_session;
679 struct UDPPongMessage *msg;
682 return GNUNET_SYSERR;
684 new_session = GNUNET_malloc (sizeof (struct Session));
685 new_session->connect_addr = GNUNET_malloc (addrlen);
686 memcpy (new_session->connect_addr, addr, addrlen);
687 new_session->connect_alen = addrlen;
690 (target, plugin->env->my_identity,
691 sizeof (struct GNUNET_PeerIdentity)) == 0)
693 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
694 ("definitely adding self to session list... hmmm\n"));
697 memcpy (&new_session->target, target, sizeof (struct GNUNET_PeerIdentity));
698 new_session->challenge = challenge;
699 new_session->validated = GNUNET_NO;
700 new_session->next = plugin->sessions;
701 plugin->sessions = new_session;
703 msg = GNUNET_malloc (sizeof (struct UDPPongMessage));
704 msg->header.size = htons (sizeof (struct UDPPongMessage));
705 msg->header.type = htons (GNUNET_MESSAGE_TYPE_TRANSPORT_UDP_PING);
706 msg->challenge = htons (challenge);
708 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
709 ("In validate, header size is %d, type %d, challenge %u\n"),
710 ntohs (msg->header.size), ntohs (msg->header.type),
711 ntohl (msg->challenge));
713 udp_plugin_send (plugin, target, GNUNET_SCHEDULER_PRIORITY_DEFAULT,
714 &msg->header, timeout, NULL, NULL);
721 * Convert the transports address to a nice, human-readable
725 * @param type name of the transport that generated the address
726 * @param addr one of the addresses of the host, NULL for the last address
727 * the specific address format depends on the transport
728 * @param addrlen length of the address
729 * @param numeric should (IP) addresses be displayed in numeric form?
730 * @param timeout after how long should we give up?
731 * @param asc function to call on each string
732 * @param asc_cls closure for asc
735 udp_plugin_address_pretty_printer (void *cls,
740 struct GNUNET_TIME_Relative timeout,
741 GNUNET_TRANSPORT_AddressStringCallback asc,
748 * Set a quota for receiving data from the given peer; this is a
749 * per-transport limit. The transport should limit its read/select
750 * calls to stay below the quota (in terms of incoming data).
753 * @param target the peer for whom the quota is given
754 * @param quota_in quota for receiving/sending data in bytes per ms
757 udp_plugin_set_receive_quota (void *cls,
758 const struct GNUNET_PeerIdentity *target,
765 * Another peer has suggested an address for this
766 * peer and transport plugin. Check that this could be a valid
767 * address. If so, consider adding it to the list
771 * @param addr pointer to the address
772 * @param addrlen length of addr
773 * @return GNUNET_OK if this is a plausible address for this peer
777 udp_plugin_address_suggested (void *cls, const void *addr, size_t addrlen)
780 return GNUNET_SYSERR;
785 * The exported method. Makes the core api available via a global and
786 * returns the udp transport API.
789 libgnunet_plugin_transport_udp_init (void *cls)
791 unsigned long long mtu;
793 struct GNUNET_TRANSPORT_PluginEnvironment *env = cls;
794 struct GNUNET_TRANSPORT_PluginFunctions *api;
795 struct Plugin *plugin;
796 struct GNUNET_SERVICE_Context *service;
797 unsigned long long aport;
798 unsigned long long bport;
800 service = GNUNET_SERVICE_start ("transport-udp", env->sched, env->cfg);
803 GNUNET_log_from (GNUNET_ERROR_TYPE_WARNING, "udp", _
804 ("Failed to start service for `%s' transport plugin.\n"),
810 GNUNET_CONFIGURATION_get_value_number (env->cfg,
816 GNUNET_CONFIGURATION_get_value_number (env->cfg,
819 &aport)) && (aport > 65535)))
821 GNUNET_log_from (GNUNET_ERROR_TYPE_ERROR,
824 ("Require valid port number for service `%s' in configuration!\n"),
826 GNUNET_SERVICE_stop (service);
834 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO,
836 _("MTU %llu for `%s' is probably too low!\n"), mtu,
839 plugin = GNUNET_malloc (sizeof (struct Plugin));
840 plugin->open_port = bport;
841 plugin->adv_port = aport;
843 plugin->statistics = NULL;
844 api = GNUNET_malloc (sizeof (struct GNUNET_TRANSPORT_PluginFunctions));
845 plugin->sessions = NULL;
848 api->validate = &udp_plugin_validate;
849 api->send = &udp_plugin_send;
850 api->disconnect = &udp_disconnect;
851 api->address_pretty_printer = &udp_plugin_address_pretty_printer;
852 api->set_receive_quota = &udp_plugin_set_receive_quota;
853 api->address_suggested = &udp_plugin_address_suggested;
854 api->cost_estimate = 17; /* TODO: ATS */
855 plugin->service = service;
857 udp_sock = udp_transport_server_start (plugin);
859 GNUNET_assert (udp_sock != NULL);
865 libgnunet_plugin_transport_udp_done (void *cls)
867 struct GNUNET_TRANSPORT_PluginFunctions *api = cls;
868 struct Plugin *plugin = api->cls;
870 struct Session *oldpos;
872 udp_transport_server_stop (plugin);
873 if (NULL != hostname_dns)
875 GNUNET_RESOLVER_request_cancel (hostname_dns);
878 GNUNET_SERVICE_stop (plugin->service);
880 pos = plugin->sessions;
883 GNUNET_free(pos->connect_addr);
889 GNUNET_NETWORK_fdset_destroy(plugin->rs);
890 GNUNET_free (plugin);
895 /* end of plugin_transport_udp.c */