2 This file is part of GNUnet
3 (C) 2001, 2002, 2003, 2004, 2005, 2008 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_YES
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,
258 const struct GNUNET_PeerIdentity *
265 * Shutdown the server process (stop receiving inbound traffic). Maybe
269 udp_transport_server_stop (void *cls)
271 struct Plugin *plugin = cls;
272 GNUNET_assert (udp_sock != NULL);
273 if (plugin->select_task != GNUNET_SCHEDULER_NO_TASK)
275 GNUNET_SCHEDULER_cancel (plugin->env->sched, plugin->select_task);
276 plugin->select_task = GNUNET_SCHEDULER_NO_TASK;
279 GNUNET_NETWORK_socket_close (udp_sock);
284 static struct Session *
285 find_session(void *cls, struct Session * session_list, const struct GNUNET_PeerIdentity *peer)
287 struct Plugin *plugin = cls;
293 if (memcmp(peer, &pos->target, sizeof(struct GNUNET_PeerIdentity)) == 0)
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, sizeof(struct GNUNET_PeerIdentity));
348 memcpy (&message[1], msg, ntohs (msg->size));
350 /* Actually send the message */
351 sent = GNUNET_NETWORK_socket_sendto (udp_sock, message, ssize, session->connect_addr,
352 session->connect_alen);
356 if (sent == GNUNET_SYSERR)
357 cont(cont_cls, target, GNUNET_SYSERR);
359 cont(cont_cls, target, GNUNET_OK);
366 * We've received a PING from this peer via UDP.
367 * Send back our PONG.
370 * @param sender the Identity of the sender
371 * @param message the actual message
374 handle_udp_ping (void *cls,
375 struct GNUNET_PeerIdentity *sender, struct sockaddr_storage * addr, size_t addrlen,
376 const struct GNUNET_MessageHeader *message)
378 struct Plugin *plugin = cls;
379 struct Session *head = plugin->sessions;
380 const struct UDPPingMessage *ping = (const struct UDPPingMessage *)message;
381 struct UDPPongMessage *pong;
382 struct Session *found;
385 GNUNET_log_from(GNUNET_ERROR_TYPE_INFO, "udp", _
386 ("handling ping, challenge is %d\n"), ntohs(ping->challenge));
388 found = find_session(plugin, head, sender);
391 pong = GNUNET_malloc(sizeof(struct UDPPongMessage) + addrlen);
392 pong->header.type = htons(GNUNET_MESSAGE_TYPE_TRANSPORT_UDP_PONG);
393 pong->header.size = htons(sizeof(struct UDPPongMessage) + addrlen);
394 pong->challenge = ping->challenge;
395 memcpy(&pong[1], addr, addrlen);
396 pong->addrlen = htons(addrlen);
398 udp_plugin_send(plugin, sender, GNUNET_SCHEDULER_PRIORITY_DEFAULT, &pong->header, GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 30), NULL, NULL);
406 * We've received a PONG from this peer via UDP.
407 * Great. Call validate func if we haven't already
411 * @param client identification of the client
412 * @param message the actual message
415 handle_udp_pong (void *cls,
416 struct GNUNET_PeerIdentity *sender,
417 const struct GNUNET_MessageHeader *message)
419 struct Plugin *plugin = cls;
420 const struct UDPPongMessage *pong = (struct UDPPongMessage *)message;
421 struct Session *found;
422 unsigned int addr_len;
423 struct sockaddr_storage addr;
426 GNUNET_log_from(GNUNET_ERROR_TYPE_INFO, "udp", _
427 ("handling pong\n"));
429 found = find_session(plugin, plugin->sessions, sender);
431 GNUNET_log_from(GNUNET_ERROR_TYPE_INFO, "udp", _
432 ("found->challenge %d, pong->challenge %d\n"), found->challenge, ntohs(pong->challenge));
434 if ((found != NULL) && (found->challenge == ntohs(pong->challenge)))
436 found->validated = GNUNET_YES;
437 addr_len = ntohs(pong->addrlen);
439 GNUNET_log_from(GNUNET_ERROR_TYPE_INFO, "udp", _
440 ("found associated ping, addr is %u bytes\n"), addr_len);
442 memcpy(&addr, &pong[1], addr_len);
443 plugin->env->notify_validation(plugin->env->cls, "udp", sender, ntohs(pong->challenge), (char *)&addr);
449 GNUNET_log_from(GNUNET_ERROR_TYPE_INFO, "udp", _
450 ("Session not found!\n"));
457 udp_plugin_select (void *cls,
458 const struct GNUNET_SCHEDULER_TaskContext *tc)
460 struct Plugin *plugin = cls;
461 struct GNUNET_TIME_Relative timeout = GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_MILLISECONDS, 500);
463 struct UDPMessage *msg;
464 const struct GNUNET_MessageHeader *hdr;
465 struct GNUNET_PeerIdentity *sender;
468 struct sockaddr_storage addr;
473 buflen = GNUNET_NETWORK_socket_recvfrom_amount(udp_sock);
476 GNUNET_log_from(GNUNET_ERROR_TYPE_INFO, "udp", _
477 ("we expect to read %u bytes\n"), buflen);
480 if (buflen == GNUNET_NO)
483 buf = GNUNET_malloc(buflen);
484 fromlen = sizeof(addr);
487 GNUNET_log_from(GNUNET_ERROR_TYPE_INFO, "udp", _
488 ("src_addr_len is %u\n"), fromlen);
491 memset(&addr, 0, fromlen);
492 ret = GNUNET_NETWORK_socket_recvfrom(udp_sock, buf, buflen, (struct sockaddr *)&addr, &fromlen);
495 GNUNET_log_from(GNUNET_ERROR_TYPE_INFO, "udp", _
496 ("socket_recv returned %u, src_addr_len is %u\n"), ret, fromlen);
505 msg = (struct UDPMessage *)buf;
508 GNUNET_log_from(GNUNET_ERROR_TYPE_INFO, "udp", _
509 ("header reports message size of %d\n"), ntohs(msg->header.size));
511 GNUNET_log_from(GNUNET_ERROR_TYPE_INFO, "udp", _
512 ("header reports message type of %d\n"), ntohs(msg->header.type));
514 /*if (ntohs(hdr->size) < sizeof(struct UDPMessage))
517 GNUNET_NETWORK_fdset_zero(plugin->rs);
518 GNUNET_NETWORK_fdset_set(plugin->rs, udp_sock);
521 hdr = (const struct GNUNET_MessageHeader *)&msg[1];
522 sender = GNUNET_malloc(sizeof(struct GNUNET_PeerIdentity));
523 memcpy(sender, &msg->sender, sizeof(struct GNUNET_PeerIdentity));
526 GNUNET_log_from(GNUNET_ERROR_TYPE_INFO, "udp", _
527 ("msg reports message size of %d\n"), ntohs(hdr->size));
529 GNUNET_log_from(GNUNET_ERROR_TYPE_INFO, "udp", _
530 ("msg reports message type of %d\n"), ntohs(hdr->type));
533 if (ntohs(hdr->type) == GNUNET_MESSAGE_TYPE_TRANSPORT_UDP_PING)
535 handle_udp_ping(plugin, sender, &addr, fromlen, hdr);
538 if (ntohs(hdr->type) == GNUNET_MESSAGE_TYPE_TRANSPORT_UDP_PONG)
540 handle_udp_pong(plugin, sender, hdr);
546 while (GNUNET_NETWORK_socket_select (plugin->rs,
549 timeout) > 0 && GNUNET_NETWORK_fdset_isset(plugin->rs, udp_sock));
551 plugin->select_task = GNUNET_SCHEDULER_add_select(plugin->env->sched, GNUNET_SCHEDULER_PRIORITY_DEFAULT, GNUNET_SCHEDULER_NO_TASK,
552 GNUNET_TIME_UNIT_FOREVER_REL, plugin->rs, NULL, &udp_plugin_select, plugin);
557 * Create a UDP socket. If possible, use IPv6, otherwise
560 static struct GNUNET_NETWORK_Handle *
561 udp_transport_server_start (void *cls)
563 struct Plugin *plugin = cls;
564 struct GNUNET_NETWORK_Handle *desc;
565 struct sockaddr_in serverAddrv4;
566 struct sockaddr_in6 serverAddrv6;
567 struct sockaddr *serverAddr;
572 GNUNET_CONFIGURATION_get_value_yesno (plugin->env->cfg, "GNUNETD", "DISABLE-IPV6"))
574 desc = GNUNET_NETWORK_socket_create (PF_INET6, SOCK_DGRAM, 17);
577 memset (&serverAddrv6, 0, sizeof (serverAddrv6));
578 #if HAVE_SOCKADDR_IN_SIN_LEN
579 serverAddrv6.sin6_len = sizeof (serverAddrv6);
581 serverAddrv6.sin6_family = AF_INET6;
582 serverAddrv6.sin6_addr = in6addr_any;
583 serverAddrv6.sin6_port = htons (plugin->open_port);
584 addrlen = sizeof (serverAddrv6);
585 serverAddr = (struct sockaddr *) &serverAddrv6;
590 desc = GNUNET_NETWORK_socket_create (PF_INET, SOCK_DGRAM, 17);
593 GNUNET_log_from(GNUNET_ERROR_TYPE_DEBUG,
600 memset (&serverAddrv4, 0, sizeof (serverAddrv4));
601 #if HAVE_SOCKADDR_IN_SIN_LEN
602 serverAddrv4.sin_len = sizeof (serverAddrv4);
604 serverAddrv4.sin_family = AF_INET;
605 serverAddrv4.sin_addr.s_addr = INADDR_ANY;
606 serverAddrv4.sin_port = htons (plugin->open_port);
607 addrlen = sizeof (serverAddrv4);
608 serverAddr = (struct sockaddr *) &serverAddrv4;
614 GNUNET_assert(GNUNET_NETWORK_socket_bind(desc, serverAddr, addrlen) == GNUNET_OK);
617 plugin->rs = GNUNET_NETWORK_fdset_create ();
619 GNUNET_NETWORK_fdset_zero(plugin->rs);
620 GNUNET_NETWORK_fdset_set(plugin->rs, desc);
622 plugin->select_task = GNUNET_SCHEDULER_add_select(plugin->env->sched, GNUNET_SCHEDULER_PRIORITY_DEFAULT, GNUNET_SCHEDULER_NO_TASK,
623 GNUNET_TIME_UNIT_FOREVER_REL, plugin->rs, NULL, &udp_plugin_select, plugin);
629 * Function that can be used by the transport service to validate that
630 * another peer is reachable at a particular address (even if we
631 * already have a connection to this peer, this function is required
632 * to establish a new one).
635 * @param target who should receive this message
636 * @param challenge challenge code to use
637 * @param addrlen length of the address
638 * @param addr the address
639 * @param timeout how long should we try to transmit these?
640 * @return GNUNET_OK if the transmission has been scheduled
643 udp_plugin_validate (void *cls,
644 const struct GNUNET_PeerIdentity *target,
646 struct GNUNET_TIME_Relative timeout,
647 const void *addr, size_t addrlen)
649 struct Plugin *plugin = cls;
650 struct Session *new_session;
651 struct UDPPongMessage *msg;
654 return GNUNET_SYSERR;
656 new_session = GNUNET_malloc(sizeof(struct Session));
657 new_session->connect_addr = GNUNET_malloc(addrlen);
658 memcpy(new_session->connect_addr, addr, addrlen);
659 new_session->connect_alen = addrlen;
661 if (memcmp(target, plugin->env->my_identity, sizeof(struct GNUNET_PeerIdentity)) == 0)
663 GNUNET_log_from(GNUNET_ERROR_TYPE_INFO, "udp", _
664 ("definitely adding self to session list... hmmm\n"));
667 memcpy(&new_session->target, target, sizeof(struct GNUNET_PeerIdentity));
668 new_session->challenge = challenge;
669 new_session->validated = GNUNET_NO;
670 new_session->next = plugin->sessions;
671 plugin->sessions = new_session;
673 msg = GNUNET_malloc (sizeof (struct UDPPongMessage));
674 msg->header.size = htons(sizeof(struct UDPPongMessage));
675 msg->header.type = htons(GNUNET_MESSAGE_TYPE_TRANSPORT_UDP_PING);
676 msg->challenge = htons(challenge);
678 GNUNET_log_from(GNUNET_ERROR_TYPE_INFO, "udp", _
679 ("In validate, header size is %d, type %d, challenge %u\n"), ntohs(msg->header.size), ntohs(msg->header.type), ntohl(msg->challenge));
681 udp_plugin_send(plugin, target, GNUNET_SCHEDULER_PRIORITY_DEFAULT, &msg->header, timeout, NULL, NULL);
687 * Convert the transports address to a nice, human-readable
691 * @param type name of the transport that generated the address
692 * @param addr one of the addresses of the host, NULL for the last address
693 * the specific address format depends on the transport
694 * @param addrlen length of the address
695 * @param numeric should (IP) addresses be displayed in numeric form?
696 * @param timeout after how long should we give up?
697 * @param asc function to call on each string
698 * @param asc_cls closure for asc
701 udp_plugin_address_pretty_printer (void *cls,
706 struct GNUNET_TIME_Relative timeout,
707 GNUNET_TRANSPORT_AddressStringCallback asc,
714 * Set a quota for receiving data from the given peer; this is a
715 * per-transport limit. The transport should limit its read/select
716 * calls to stay below the quota (in terms of incoming data).
719 * @param target the peer for whom the quota is given
720 * @param quota_in quota for receiving/sending data in bytes per ms
723 udp_plugin_set_receive_quota (void *cls,
724 const struct GNUNET_PeerIdentity *target,
731 * Another peer has suggested an address for this
732 * peer and transport plugin. Check that this could be a valid
733 * address. If so, consider adding it to the list
737 * @param addr pointer to the address
738 * @param addrlen length of addr
739 * @return GNUNET_OK if this is a plausible address for this peer
743 udp_plugin_address_suggested (void *cls, const void *addr, size_t addrlen)
746 return GNUNET_SYSERR;
751 * The exported method. Makes the core api available via a global and
752 * returns the udp transport API.
755 libgnunet_plugin_transport_udp_init (void *cls)
757 unsigned long long mtu;
759 struct GNUNET_TRANSPORT_PluginEnvironment *env = cls;
760 struct GNUNET_TRANSPORT_PluginFunctions *api;
761 struct Plugin *plugin;
762 struct GNUNET_SERVICE_Context *service;
763 unsigned long long aport;
764 unsigned long long bport;
766 service = GNUNET_SERVICE_start ("transport-udp", env->sched, env->cfg);
769 GNUNET_log_from(GNUNET_ERROR_TYPE_WARNING, "udp", _
770 ("Failed to start service for `%s' transport plugin.\n"), "udp");
775 GNUNET_CONFIGURATION_get_value_number (env->cfg,
781 GNUNET_CONFIGURATION_get_value_number (env->cfg,
784 &aport)) && (aport > 65535)))
786 GNUNET_log_from (GNUNET_ERROR_TYPE_ERROR,
789 ("Require valid port number for service `%s' in configuration!\n"),
791 GNUNET_SERVICE_stop (service);
799 GNUNET_log_from(GNUNET_ERROR_TYPE_INFO,
801 _("MTU %llu for `%s' is probably too low!\n"), mtu, "UDP");
803 plugin = GNUNET_malloc (sizeof (struct Plugin));
804 plugin->open_port = bport;
805 plugin->adv_port = aport;
807 plugin->statistics = NULL;
808 api = GNUNET_malloc (sizeof (struct GNUNET_TRANSPORT_PluginFunctions));
809 plugin->sessions = NULL;
812 api->validate = &udp_plugin_validate;
813 api->send = &udp_plugin_send;
814 api->disconnect = &udp_disconnect;
815 api->address_pretty_printer = &udp_plugin_address_pretty_printer;
816 api->set_receive_quota = &udp_plugin_set_receive_quota;
817 api->address_suggested = &udp_plugin_address_suggested;
818 api->cost_estimate = 17; /* TODO: ATS */
819 plugin->service = service;
821 udp_sock = udp_transport_server_start(plugin);
823 GNUNET_assert(udp_sock != NULL);
829 libgnunet_plugin_transport_udp_done (void *cls)
831 struct GNUNET_TRANSPORT_PluginFunctions *api = cls;
832 struct Plugin *plugin = api->cls;
834 udp_transport_server_stop(plugin);
835 if (NULL != hostname_dns)
837 GNUNET_RESOLVER_request_cancel (hostname_dns);
840 GNUNET_SERVICE_stop (plugin->service);
841 GNUNET_free (plugin);
846 /* end of plugin_transport_udp.c */