2 This file is part of GNUnet
3 (C) 2010 Christian Grothoff (and other contributing authors)
5 GNUnet is free software; you can redistribute it and/or modify
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
8 option) any later version.
10 GNUnet is distributed in the hope that it will be useful, but
11 WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with GNUnet; see the file COPYING. If not, write to the
17 Free Software Foundation, Inc., 59 Temple Place - Suite 330,
18 Boston, MA 02111-1307, USA.
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 addr the addr to send the message to, needs to be a sockaddr for us
188 * @param addrlen the len of addr
189 * @param force_address not used, we had better have an address to send to
190 * because we are stateless!!
191 * @param cont continuation to call once the message has
192 * been transmitted (or if the transport is ready
193 * for the next transmission call; or if the
194 * peer disconnected...)
195 * @param cont_cls closure for cont
197 * @return the number of bytes written, -1 on error (in this case, cont is not called)
200 udp_plugin_send (void *cls,
201 const struct GNUNET_PeerIdentity *target,
204 unsigned int priority,
205 struct GNUNET_TIME_Relative timeout,
209 GNUNET_TRANSPORT_TransmitContinuation cont, void *cont_cls)
211 struct Plugin *plugin = cls;
212 struct UDPMessage *message;
216 GNUNET_assert(udp_sock != NULL);
217 if ( (addr == NULL) || (addrlen == 0) )
220 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
221 ("udp_plugin_send called without address, returning!\n"));
223 return -1; /* Can never send if we don't have an address!! */
226 /* Build the message to be sent */
227 message = GNUNET_malloc (sizeof (struct UDPMessage) + msgbuf_size);
228 ssize = sizeof (struct UDPMessage) + msgbuf_size;
231 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
232 ("In udp_send, ssize is %d, sending message to %s\n"), ssize, GNUNET_a2s((const struct sockaddr *)addr, addrlen));
234 message->header.size = htons (ssize);
235 message->header.type = htons (0);
236 memcpy (&message->sender, plugin->env->my_identity,
237 sizeof (struct GNUNET_PeerIdentity));
238 memcpy (&message[1], msgbuf, msgbuf_size);
240 GNUNET_NETWORK_socket_sendto (udp_sock, message, ssize,
243 if ( (cont != NULL) &&
245 cont (cont_cls, target, GNUNET_OK);
246 GNUNET_free (message);
252 * Add the IP of our network interface to the list of
253 * our external IP addresses.
256 process_interfaces (void *cls,
259 const struct sockaddr *addr, socklen_t addrlen)
261 struct Plugin *plugin = cls;
263 struct sockaddr_in *v4;
264 struct sockaddr_in6 *v6;
266 af = addr->sa_family;
269 v4 = (struct sockaddr_in *) addr;
270 v4->sin_port = htons (plugin->adv_port);
274 GNUNET_assert (af == AF_INET6);
275 v6 = (struct sockaddr_in6 *) addr;
276 v6->sin6_port = htons (plugin->adv_port);
278 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO |
279 GNUNET_ERROR_TYPE_BULK,
280 "udp", _("Found address `%s' (%s)\n"),
281 GNUNET_a2s (addr, addrlen), name);
282 plugin->env->notify_address (plugin->env->cls,
284 addr, addrlen, GNUNET_TIME_UNIT_FOREVER_REL);
291 * Function called by the resolver for each address obtained from DNS
292 * for our own hostname. Add the addresses to the list of our
293 * external IP addresses.
296 * @param addr one of the addresses of the host, NULL for the last address
297 * @param addrlen length of the address
300 process_hostname_ips (void *cls,
301 const struct sockaddr *addr, socklen_t addrlen)
303 struct Plugin *plugin = cls;
307 plugin->hostname_dns = NULL;
310 process_interfaces (plugin, "<hostname>", GNUNET_YES, addr, addrlen);
315 * @param cls the plugin handle
316 * @param tc the scheduling context (for rescheduling this function again)
318 * We have been notified that our writeset has something to read. Presumably
319 * select has been called already, so we can go ahead and start reading from
320 * the socket immediately. Then we check if there is more to be read by
321 * calling select ourselves while there is stuff on the wire. Then reschedule
322 * this function to be called again once more is available.
326 udp_plugin_select (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
328 struct Plugin *plugin = cls;
330 struct UDPMessage *msg;
331 struct GNUNET_PeerIdentity *sender;
334 struct sockaddr_storage addr;
340 const struct GNUNET_MessageHeader *currhdr;
343 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
344 ("entered select...\n"));
347 buflen = GNUNET_NETWORK_socket_recvfrom_amount (udp_sock);
350 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
351 ("we expect to read %u bytes\n"), buflen);
354 if (buflen == GNUNET_NO)
357 buf = GNUNET_malloc (buflen);
358 fromlen = sizeof (addr);
360 memset (&addr, 0, fromlen);
362 GNUNET_NETWORK_socket_recvfrom (udp_sock, buf, buflen,
363 (struct sockaddr *) &addr, &fromlen);
366 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
367 ("socket_recv returned %u, src_addr_len is %u\n"), ret,
376 msg = (struct UDPMessage *) buf;
379 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
380 ("header reports message size of %d\n"),
381 ntohs (msg->header.size));
383 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
384 ("header reports message type of %d\n"),
385 ntohs (msg->header.type));
387 if (ntohs (msg->header.size) < sizeof (struct UDPMessage))
390 GNUNET_NETWORK_fdset_zero (plugin->rs);
391 GNUNET_NETWORK_fdset_set (plugin->rs, udp_sock);
394 msgbuf = (char *)&msg[1];
395 sender = GNUNET_malloc (sizeof (struct GNUNET_PeerIdentity));
396 memcpy (sender, &msg->sender, sizeof (struct GNUNET_PeerIdentity));
400 tsize = ntohs (msg->header.size) - sizeof(struct UDPMessage);
402 GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "UDP", _
403 ("offset is %d, tsize is %d (UDPMessage size is %d)\n"),
404 offset, tsize, sizeof(struct UDPMessage));
406 while (offset < tsize)
408 currhdr = (struct GNUNET_MessageHeader *)&msgbuf[offset];
410 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
411 ("processing msg %d: type %d, size %d at offset %d\n"),
412 count, ntohs(currhdr->type), ntohs(currhdr->size), offset);
414 plugin->env->receive (plugin->env->cls,
415 sender, currhdr, UDP_DIRECT_DISTANCE, (char *)&addr, fromlen);
416 offset += ntohs(currhdr->size);
418 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
419 ("offset now %d, tsize %d\n"),
425 GNUNET_free (sender);
428 plugin->select_task =
429 GNUNET_SCHEDULER_add_select (plugin->env->sched,
430 GNUNET_SCHEDULER_PRIORITY_DEFAULT,
431 GNUNET_SCHEDULER_NO_TASK,
432 GNUNET_TIME_UNIT_FOREVER_REL, plugin->rs,
433 NULL, &udp_plugin_select, plugin);
438 * Create a UDP socket. If possible, use IPv6, otherwise
441 static struct GNUNET_NETWORK_Handle *
442 udp_transport_server_start (void *cls)
444 struct Plugin *plugin = cls;
445 struct GNUNET_NETWORK_Handle *desc;
446 struct sockaddr_in serverAddrv4;
447 struct sockaddr_in6 serverAddrv6;
448 struct sockaddr *serverAddr;
453 GNUNET_CONFIGURATION_get_value_yesno (plugin->env->cfg, "GNUNETD",
456 desc = GNUNET_NETWORK_socket_create (PF_INET6, SOCK_DGRAM, 17);
459 memset (&serverAddrv6, 0, sizeof (serverAddrv6));
460 #if HAVE_SOCKADDR_IN_SIN_LEN
461 serverAddrv6.sin6_len = sizeof (serverAddrv6);
463 serverAddrv6.sin6_family = AF_INET6;
464 serverAddrv6.sin6_addr = in6addr_any;
465 serverAddrv6.sin6_port = htons (plugin->open_port);
466 addrlen = sizeof (serverAddrv6);
467 serverAddr = (struct sockaddr *) &serverAddrv6;
472 desc = GNUNET_NETWORK_socket_create (PF_INET, SOCK_DGRAM, 17);
475 GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "udp", "socket");
480 memset (&serverAddrv4, 0, sizeof (serverAddrv4));
481 #if HAVE_SOCKADDR_IN_SIN_LEN
482 serverAddrv4.sin_len = sizeof (serverAddrv4);
484 serverAddrv4.sin_family = AF_INET;
485 serverAddrv4.sin_addr.s_addr = INADDR_ANY;
486 serverAddrv4.sin_port = htons (plugin->open_port);
487 addrlen = sizeof (serverAddrv4);
488 serverAddr = (struct sockaddr *) &serverAddrv4;
494 GNUNET_assert (GNUNET_NETWORK_socket_bind (desc, serverAddr, addrlen) ==
498 plugin->rs = GNUNET_NETWORK_fdset_create ();
500 GNUNET_NETWORK_fdset_zero (plugin->rs);
501 GNUNET_NETWORK_fdset_set (plugin->rs, desc);
503 plugin->select_task =
504 GNUNET_SCHEDULER_add_select (plugin->env->sched,
505 GNUNET_SCHEDULER_PRIORITY_DEFAULT,
506 GNUNET_SCHEDULER_NO_TASK,
507 GNUNET_TIME_UNIT_FOREVER_REL, plugin->rs,
508 NULL, &udp_plugin_select, plugin);
515 * Check if the given port is plausible (must be either
516 * our listen port or our advertised port). If it is
517 * neither, we return one of these two ports at random.
519 * @return either in_port or a more plausible port
522 check_port (struct Plugin *plugin, uint16_t in_port)
524 if ((in_port == plugin->adv_port) || (in_port == plugin->open_port))
526 return (GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK,
528 ? plugin->open_port : plugin->adv_port;
533 * Another peer has suggested an address for this peer and transport
534 * plugin. Check that this could be a valid address. This function
535 * is not expected to 'validate' the address in the sense of trying to
536 * connect to it but simply to see if the binary format is technically
537 * legal for establishing a connection.
539 * @param cls handle to Plugin
540 * @param addr address to check
541 * @param addrlen length of addr
542 * @return GNUNET_OK if this is a plausible address for this peer
543 * and transport, GNUNET_SYSERR if not
545 * TODO: perhaps make everything work with sockaddr_storage, it may
546 * be a cleaner way to handle addresses in UDP
549 udp_check_address (void *cls, void *addr, size_t addrlen)
551 struct Plugin *plugin = cls;
552 char buf[sizeof (struct sockaddr_in6)];
554 struct sockaddr_in *v4;
555 struct sockaddr_in6 *v6;
557 if ((addrlen != sizeof (struct sockaddr_in)) &&
558 (addrlen != sizeof (struct sockaddr_in6)))
561 return GNUNET_SYSERR;
563 memcpy (buf, addr, sizeof (struct sockaddr_in6));
564 if (addrlen == sizeof (struct sockaddr_in))
566 v4 = (struct sockaddr_in *) buf;
567 v4->sin_port = htons (check_port (plugin, ntohs (v4->sin_port)));
571 v6 = (struct sockaddr_in6 *) buf;
572 v6->sin6_port = htons (check_port (plugin, ntohs (v6->sin6_port)));
575 GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG,
577 "Informing transport service about my address `%s'.\n",
578 GNUNET_a2s (addr, addrlen));
586 * Append our port and forward the result.
589 append_port (void *cls, const char *hostname)
591 struct PrettyPrinterContext *ppc = cls;
594 if (hostname == NULL)
596 ppc->asc (ppc->asc_cls, NULL);
600 GNUNET_asprintf (&ret, "%s:%d", hostname, ppc->port);
601 ppc->asc (ppc->asc_cls, ret);
607 * Convert the transports address to a nice, human-readable
611 * @param type name of the transport that generated the address
612 * @param addr one of the addresses of the host, NULL for the last address
613 * the specific address format depends on the transport
614 * @param addrlen length of the address
615 * @param numeric should (IP) addresses be displayed in numeric form?
616 * @param timeout after how long should we give up?
617 * @param asc function to call on each string
618 * @param asc_cls closure for asc
621 udp_plugin_address_pretty_printer (void *cls,
626 struct GNUNET_TIME_Relative timeout,
627 GNUNET_TRANSPORT_AddressStringCallback asc,
630 struct Plugin *plugin = cls;
631 const struct sockaddr_in *v4;
632 const struct sockaddr_in6 *v6;
633 struct PrettyPrinterContext *ppc;
635 if ((addrlen != sizeof (struct sockaddr_in)) &&
636 (addrlen != sizeof (struct sockaddr_in6)))
638 /* invalid address */
643 ppc = GNUNET_malloc (sizeof (struct PrettyPrinterContext));
645 ppc->asc_cls = asc_cls;
646 if (addrlen == sizeof (struct sockaddr_in))
648 v4 = (const struct sockaddr_in *) addr;
649 ppc->port = ntohs (v4->sin_port);
653 v6 = (const struct sockaddr_in6 *) addr;
654 ppc->port = ntohs (v6->sin6_port);
657 GNUNET_RESOLVER_hostname_get (plugin->env->sched,
661 !numeric, timeout, &append_port, ppc);
666 * The exported method. Makes the core api available via a global and
667 * returns the udp transport API.
670 libgnunet_plugin_transport_udp_init (void *cls)
672 struct GNUNET_TRANSPORT_PluginEnvironment *env = cls;
673 struct GNUNET_TRANSPORT_PluginFunctions *api;
674 struct Plugin *plugin;
675 struct GNUNET_SERVICE_Context *service;
676 unsigned long long aport;
677 unsigned long long bport;
678 unsigned long long mtu;
680 service = GNUNET_SERVICE_start ("transport-udp", env->sched, env->cfg);
683 GNUNET_log_from (GNUNET_ERROR_TYPE_WARNING, "udp", _
684 ("Failed to start service for `%s' transport plugin.\n"),
690 GNUNET_CONFIGURATION_get_value_number (env->cfg,
696 GNUNET_CONFIGURATION_get_value_number (env->cfg,
699 &aport)) && (aport > 65535)))
701 GNUNET_log_from (GNUNET_ERROR_TYPE_ERROR,
704 ("Require valid port number for service `%s' in configuration!\n"),
706 GNUNET_SERVICE_stop (service);
714 GNUNET_log_from (GNUNET_ERROR_TYPE_INFO,
716 _("MTU %llu for `%s' is probably too low!\n"), mtu,
719 plugin = GNUNET_malloc (sizeof (struct Plugin));
720 plugin->open_port = bport;
721 plugin->adv_port = aport;
723 plugin->statistics = NULL;
724 api = GNUNET_malloc (sizeof (struct GNUNET_TRANSPORT_PluginFunctions));
727 api->send = &udp_plugin_send;
728 api->disconnect = &udp_disconnect;
729 api->address_pretty_printer = &udp_plugin_address_pretty_printer;
730 api->check_address = &udp_check_address;
732 plugin->service = service;
734 /* FIXME: do the two calls below periodically again and
735 not just once (since the info we get might change...) */
736 GNUNET_OS_network_interfaces_list (&process_interfaces, plugin);
737 plugin->hostname_dns = GNUNET_RESOLVER_hostname_resolve (env->sched,
740 HOSTNAME_RESOLVE_TIMEOUT,
741 &process_hostname_ips,
744 udp_sock = udp_transport_server_start (plugin);
746 GNUNET_assert (udp_sock != NULL);
752 libgnunet_plugin_transport_udp_done (void *cls)
754 struct GNUNET_TRANSPORT_PluginFunctions *api = cls;
755 struct Plugin *plugin = api->cls;
757 udp_transport_server_stop (plugin);
758 if (NULL != plugin->hostname_dns)
760 GNUNET_RESOLVER_request_cancel (plugin->hostname_dns);
761 plugin->hostname_dns = NULL;
763 GNUNET_SERVICE_stop (plugin->service);
765 GNUNET_NETWORK_fdset_destroy (plugin->rs);
766 GNUNET_free (plugin);
771 /* end of plugin_transport_udp.c */