2 This file is part of GNUnet.
3 (C) 2013 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 3, 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 #include "gnunet_util_lib.h"
24 #include "gnunet_signatures.h"
25 #include "gnunet_statistics_service.h"
27 #include "cadet_protocol.h"
28 #include "cadet_path.h"
30 #include "gnunet-service-cadet_tunnel.h"
31 #include "gnunet-service-cadet_connection.h"
32 #include "gnunet-service-cadet_channel.h"
33 #include "gnunet-service-cadet_peer.h"
35 #define LOG(level, ...) GNUNET_log_from(level,"cadet-tun",__VA_ARGS__)
36 #define LOG2(level, ...) GNUNET_log_from_nocheck(level,"cadet-tun",__VA_ARGS__)
38 #define REKEY_WAIT GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_SECONDS, 5)
40 #if !defined(GNUNET_CULL_LOGGING)
41 #define DUMP_KEYS_TO_STDERR GNUNET_YES
43 #define DUMP_KEYS_TO_STDERR GNUNET_NO
46 /******************************************************************************/
47 /******************************** STRUCTS **********************************/
48 /******************************************************************************/
52 struct CadetTChannel *next;
53 struct CadetTChannel *prev;
54 struct CadetChannel *ch;
59 * Connection list and metadata.
61 struct CadetTConnection
66 struct CadetTConnection *next;
71 struct CadetTConnection *prev;
76 struct CadetConnection *c;
79 * Creation time, to keep oldest connection alive.
81 struct GNUNET_TIME_Absolute created;
84 * Connection throughput, to keep fastest connection alive.
90 * Structure used during a Key eXchange.
92 struct CadetTunnelKXCtx
95 * Encryption ("our") old "confirmed" key, for encrypting traffic sent by us
96 * end before the key exchange is finished or times out.
98 struct GNUNET_CRYPTO_SymmetricSessionKey e_key_old;
101 * Decryption ("their") old "confirmed" key, for decrypting traffic sent by
102 * the other end before the key exchange started.
104 struct GNUNET_CRYPTO_SymmetricSessionKey d_key_old;
107 * Challenge to send in a ping and expect in the pong.
112 * When the rekey started. One minute after this the new key will be used.
114 struct GNUNET_TIME_Absolute rekey_start_time;
117 * Task for delayed destruction of the Key eXchange context, to allow delayed
118 * messages with the old key to be decrypted successfully.
120 GNUNET_SCHEDULER_TaskIdentifier finish_task;
124 * Struct containing all information regarding a tunnel to a peer.
129 * Endpoint of the tunnel.
131 struct CadetPeer *peer;
134 * State of the tunnel connectivity.
136 enum CadetTunnelCState cstate;
139 * State of the tunnel encryption.
141 enum CadetTunnelEState estate;
144 * Key eXchange context.
146 struct CadetTunnelKXCtx *kx_ctx;
149 * Peer's ephemeral key, to recreate @c e_key and @c d_key when own ephemeral
152 struct GNUNET_CRYPTO_EcdhePublicKey peers_ephemeral_key;
155 * Encryption ("our") key. It is only "confirmed" if kx_ctx is NULL.
157 struct GNUNET_CRYPTO_SymmetricSessionKey e_key;
160 * Decryption ("their") key. It is only "confirmed" if kx_ctx is NULL.
162 struct GNUNET_CRYPTO_SymmetricSessionKey d_key;
165 * Task to start the rekey process.
167 GNUNET_SCHEDULER_TaskIdentifier rekey_task;
170 * Paths that are actively used to reach the destination peer.
172 struct CadetTConnection *connection_head;
173 struct CadetTConnection *connection_tail;
176 * Next connection number.
181 * Channels inside this tunnel.
183 struct CadetTChannel *channel_head;
184 struct CadetTChannel *channel_tail;
187 * Channel ID for the next created channel.
189 CADET_ChannelNumber next_chid;
192 * Destroy flag: if true, destroy on last message.
194 GNUNET_SCHEDULER_TaskIdentifier destroy_task;
197 * Queued messages, to transmit once tunnel gets connected.
199 struct CadetTunnelDelayed *tq_head;
200 struct CadetTunnelDelayed *tq_tail;
203 * Task to trim connections if too many are present.
205 GNUNET_SCHEDULER_TaskIdentifier trim_connections_task;
208 * Ephemeral message in the queue (to avoid queueing more than one).
210 struct CadetConnectionQueue *ephm_h;
213 * Pong message in the queue.
215 struct CadetConnectionQueue *pong_h;
220 * Struct used to save messages in a non-ready tunnel to send once connected.
222 struct CadetTunnelDelayed
227 struct CadetTunnelDelayed *next;
228 struct CadetTunnelDelayed *prev;
233 struct CadetTunnel *t;
236 * Tunnel queue given to the channel to cancel request. Update on send_queued.
238 struct CadetTunnelQueue *tq;
243 /* struct GNUNET_MessageHeader *msg; */
248 * Handle for messages queued but not yet sent.
250 struct CadetTunnelQueue
253 * Connection queue handle, to cancel if necessary.
255 struct CadetConnectionQueue *cq;
258 * Handle in case message hasn't been given to a connection yet.
260 struct CadetTunnelDelayed *tqd;
263 * Continuation to call once sent.
268 * Closure for @c cont.
274 /******************************************************************************/
275 /******************************* GLOBALS ***********************************/
276 /******************************************************************************/
279 * Global handle to the statistics service.
281 extern struct GNUNET_STATISTICS_Handle *stats;
284 * Local peer own ID (memory efficient handle).
286 extern GNUNET_PEER_Id myid;
289 * Local peer own ID (full value).
291 extern struct GNUNET_PeerIdentity my_full_id;
295 * Don't try to recover tunnels if shutting down.
297 extern int shutting_down;
301 * Set of all tunnels, in order to trigger a new exchange on rekey.
302 * Indexed by peer's ID.
304 static struct GNUNET_CONTAINER_MultiPeerMap *tunnels;
307 * Default TTL for payload packets.
309 static unsigned long long default_ttl;
314 const static struct GNUNET_CRYPTO_EddsaPrivateKey *my_private_key;
317 * Own ephemeral private key.
319 static struct GNUNET_CRYPTO_EcdhePrivateKey *my_ephemeral_key;
322 * Cached message used to perform a key exchange.
324 static struct GNUNET_CADET_KX_Ephemeral kx_msg;
327 * Task to generate a new ephemeral key.
329 static GNUNET_SCHEDULER_TaskIdentifier rekey_task;
334 static struct GNUNET_TIME_Relative rekey_period;
336 /******************************************************************************/
337 /******************************** STATIC ***********************************/
338 /******************************************************************************/
341 * Get string description for tunnel connectivity state.
343 * @param cs Tunnel state.
345 * @return String representation.
348 cstate2s (enum CadetTunnelCState cs)
354 case CADET_TUNNEL_NEW:
355 return "CADET_TUNNEL_NEW";
356 case CADET_TUNNEL_SEARCHING:
357 return "CADET_TUNNEL_SEARCHING";
358 case CADET_TUNNEL_WAITING:
359 return "CADET_TUNNEL_WAITING";
360 case CADET_TUNNEL_READY:
361 return "CADET_TUNNEL_READY";
362 case CADET_TUNNEL_SHUTDOWN:
363 return "CADET_TUNNEL_SHUTDOWN";
365 SPRINTF (buf, "%u (UNKNOWN STATE)", cs);
373 * Get string description for tunnel encryption state.
375 * @param es Tunnel state.
377 * @return String representation.
380 estate2s (enum CadetTunnelEState es)
386 case CADET_TUNNEL_KEY_UNINITIALIZED:
387 return "CADET_TUNNEL_KEY_UNINITIALIZED";
388 case CADET_TUNNEL_KEY_SENT:
389 return "CADET_TUNNEL_KEY_SENT";
390 case CADET_TUNNEL_KEY_PING:
391 return "CADET_TUNNEL_KEY_PING";
392 case CADET_TUNNEL_KEY_OK:
393 return "CADET_TUNNEL_KEY_OK";
394 case CADET_TUNNEL_KEY_REKEY:
395 return "CADET_TUNNEL_KEY_REKEY";
397 SPRINTF (buf, "%u (UNKNOWN STATE)", es);
405 * @brief Check if tunnel is ready to send traffic.
407 * Tunnel must be connected and with encryption correctly set up.
409 * @param t Tunnel to check.
411 * @return #GNUNET_YES if ready, #GNUNET_NO otherwise
414 is_ready (struct CadetTunnel *t)
418 GCT_debug (t, GNUNET_ERROR_TYPE_DEBUG);
419 ready = CADET_TUNNEL_READY == t->cstate
420 && (CADET_TUNNEL_KEY_OK == t->estate
421 || CADET_TUNNEL_KEY_REKEY == t->estate);
422 ready = ready || GCT_is_loopback (t);
428 * Check if a key is invalid (NULL pointer or all 0)
430 * @param key Key to check.
432 * @return #GNUNET_YES if key is null, #GNUNET_NO if exists and is not 0.
435 is_key_null (struct GNUNET_CRYPTO_SymmetricSessionKey *key)
437 struct GNUNET_CRYPTO_SymmetricSessionKey null_key;
442 memset (&null_key, 0, sizeof (null_key));
443 if (0 == memcmp (key, &null_key, sizeof (null_key)))
450 * Ephemeral key message purpose size.
452 * @return Size of the part of the ephemeral key message that must be signed.
455 ephemeral_purpose_size (void)
457 return sizeof (struct GNUNET_CRYPTO_EccSignaturePurpose) +
458 sizeof (struct GNUNET_TIME_AbsoluteNBO) +
459 sizeof (struct GNUNET_TIME_AbsoluteNBO) +
460 sizeof (struct GNUNET_CRYPTO_EcdhePublicKey) +
461 sizeof (struct GNUNET_PeerIdentity);
466 * Size of the encrypted part of a ping message.
468 * @return Size of the encrypted part of a ping message.
471 ping_encryption_size (void)
473 return sizeof (uint32_t);
478 * Get the channel's buffer. ONLY FOR NON-LOOPBACK CHANNELS!!
480 * @param tch Tunnel's channel handle.
482 * @return Amount of messages the channel can still buffer towards the client.
485 get_channel_buffer (const struct CadetTChannel *tch)
489 /* If channel is incoming, is terminal in the FWD direction and fwd is YES */
490 fwd = GCCH_is_terminal (tch->ch, GNUNET_YES);
492 return GCCH_get_buffer (tch->ch, fwd);
497 * Get the channel's allowance status.
499 * @param tch Tunnel's channel handle.
501 * @return #GNUNET_YES if we allowed the client to send data to us.
504 get_channel_allowed (const struct CadetTChannel *tch)
508 /* If channel is outgoing, is origin in the FWD direction and fwd is YES */
509 fwd = GCCH_is_origin (tch->ch, GNUNET_YES);
511 return GCCH_get_allowed (tch->ch, fwd);
516 * Get the connection's buffer.
518 * @param tc Tunnel's connection handle.
520 * @return Amount of messages the connection can still buffer.
523 get_connection_buffer (const struct CadetTConnection *tc)
527 /* If connection is outgoing, is origin in the FWD direction and fwd is YES */
528 fwd = GCC_is_origin (tc->c, GNUNET_YES);
530 return GCC_get_buffer (tc->c, fwd);
535 * Get the connection's allowance.
537 * @param tc Tunnel's connection handle.
539 * @return Amount of messages we have allowed the next peer to send us.
542 get_connection_allowed (const struct CadetTConnection *tc)
546 /* If connection is outgoing, is origin in the FWD direction and fwd is YES */
547 fwd = GCC_is_origin (tc->c, GNUNET_YES);
549 return GCC_get_allowed (tc->c, fwd);
554 * Check that a ephemeral key message s well formed and correctly signed.
556 * @param t Tunnel on which the message came.
557 * @param msg The ephemeral key message.
559 * @return GNUNET_OK if message is fine, GNUNET_SYSERR otherwise.
562 check_ephemeral (struct CadetTunnel *t,
563 const struct GNUNET_CADET_KX_Ephemeral *msg)
565 /* Check message size */
566 if (ntohs (msg->header.size) != sizeof (struct GNUNET_CADET_KX_Ephemeral))
567 return GNUNET_SYSERR;
569 /* Check signature size */
570 if (ntohl (msg->purpose.size) != ephemeral_purpose_size ())
571 return GNUNET_SYSERR;
574 if (0 != memcmp (&msg->origin_identity,
575 GCP_get_id (t->peer),
576 sizeof (struct GNUNET_PeerIdentity)))
577 return GNUNET_SYSERR;
579 /* Check signature */
581 GNUNET_CRYPTO_eddsa_verify (GNUNET_SIGNATURE_PURPOSE_CADET_KX,
584 &msg->origin_identity.public_key))
585 return GNUNET_SYSERR;
592 * Select the best key to use for encryption (send), based on KX status.
594 * Normally, return the current key. If there is a KX in progress and the old
595 * key is fresh enough, return the old key.
597 * @param t Tunnel to choose the key from.
599 * @return The optimal key to encrypt/hmac outgoing traffic.
601 static const struct GNUNET_CRYPTO_SymmetricSessionKey *
602 select_key (const struct CadetTunnel *t)
604 const struct GNUNET_CRYPTO_SymmetricSessionKey *key;
606 if (NULL != t->kx_ctx
607 && GNUNET_SCHEDULER_NO_TASK == t->kx_ctx->finish_task)
609 struct GNUNET_TIME_Relative age;
611 age = GNUNET_TIME_absolute_get_duration (t->kx_ctx->rekey_start_time);
612 LOG (GNUNET_ERROR_TYPE_DEBUG,
613 " key exchange in progress, started %s ago\n",
614 GNUNET_STRINGS_relative_time_to_string (age, GNUNET_YES));
615 // FIXME make duration of old keys configurable
616 if (age.rel_value_us < GNUNET_TIME_UNIT_MINUTES.rel_value_us)
618 LOG (GNUNET_ERROR_TYPE_DEBUG, " using old key\n");
619 key = &t->kx_ctx->e_key_old;
623 LOG (GNUNET_ERROR_TYPE_DEBUG, " using new key (old key too old)\n");
629 LOG (GNUNET_ERROR_TYPE_DEBUG, " no KX: using current key\n");
639 * @param plaintext Content to HMAC.
640 * @param size Size of @c plaintext.
641 * @param iv Initialization vector for the message.
642 * @param key Key to use.
643 * @param hmac[out] Destination to store the HMAC.
646 t_hmac (const void *plaintext, size_t size,
647 uint32_t iv, const struct GNUNET_CRYPTO_SymmetricSessionKey *key,
648 struct GNUNET_CADET_Hash *hmac)
650 static const char ctx[] = "cadet authentication key";
651 struct GNUNET_CRYPTO_AuthKey auth_key;
652 struct GNUNET_HashCode hash;
654 #if DUMP_KEYS_TO_STDERR
655 LOG (GNUNET_ERROR_TYPE_INFO, " HMAC with key %s\n",
656 GNUNET_h2s ((struct GNUNET_HashCode *) key));
658 GNUNET_CRYPTO_hmac_derive_key (&auth_key, key,
663 /* Two step: CADET_Hash is only 256 bits, HashCode is 512. */
664 GNUNET_CRYPTO_hmac (&auth_key, plaintext, size, &hash);
665 memcpy (hmac, &hash, sizeof (*hmac));
670 * Encrypt daforce_newest_keyta with the tunnel key.
672 * @param t Tunnel whose key to use.
673 * @param dst Destination for the encrypted data.
674 * @param src Source of the plaintext. Can overlap with @c dst.
675 * @param size Size of the plaintext.
676 * @param iv Initialization Vector to use.
677 * @param force_newest_key Force the use of the newest key, otherwise
678 * CADET will use the old key when allowed.
679 * This can happen in the case when a KX is going on
680 * and the old one hasn't expired.
683 t_encrypt (struct CadetTunnel *t, void *dst, const void *src,
684 size_t size, uint32_t iv, int force_newest_key)
686 struct GNUNET_CRYPTO_SymmetricInitializationVector siv;
687 const struct GNUNET_CRYPTO_SymmetricSessionKey *key;
690 LOG (GNUNET_ERROR_TYPE_DEBUG, " t_encrypt start\n");
692 key = GNUNET_YES == force_newest_key ? &t->e_key : select_key (t);
693 #if DUMP_KEYS_TO_STDERR
694 LOG (GNUNET_ERROR_TYPE_INFO, " ENC with key %s\n",
695 GNUNET_h2s ((struct GNUNET_HashCode *) key));
697 GNUNET_CRYPTO_symmetric_derive_iv (&siv, key, &iv, sizeof (iv), NULL);
698 LOG (GNUNET_ERROR_TYPE_DEBUG, " t_encrypt IV derived\n");
699 out_size = GNUNET_CRYPTO_symmetric_encrypt (src, size, key, &siv, dst);
700 LOG (GNUNET_ERROR_TYPE_DEBUG, " t_encrypt end\n");
707 * Decrypt and verify data with the appropriate tunnel key.
709 * @param key Key to use.
710 * @param dst Destination for the plaintext.
711 * @param src Source of the encrypted data. Can overlap with @c dst.
712 * @param size Size of the encrypted data.
713 * @param iv Initialization Vector to use.
715 * @return Size of the decrypted data, -1 if an error was encountered.
718 decrypt (const struct GNUNET_CRYPTO_SymmetricSessionKey *key,
719 void *dst, const void *src, size_t size, uint32_t iv)
721 struct GNUNET_CRYPTO_SymmetricInitializationVector siv;
724 LOG (GNUNET_ERROR_TYPE_DEBUG, " decrypt start\n");
725 LOG (GNUNET_ERROR_TYPE_DEBUG, " decrypt iv\n");
726 GNUNET_CRYPTO_symmetric_derive_iv (&siv, key, &iv, sizeof (iv), NULL);
727 LOG (GNUNET_ERROR_TYPE_DEBUG, " decrypt iv done\n");
728 out_size = GNUNET_CRYPTO_symmetric_decrypt (src, size, key, &siv, dst);
729 LOG (GNUNET_ERROR_TYPE_DEBUG, " decrypt end\n");
736 * Decrypt and verify data with the most recent tunnel key.
738 * @param t Tunnel whose key to use.
739 * @param dst Destination for the plaintext.
740 * @param src Source of the encrypted data. Can overlap with @c dst.
741 * @param size Size of the encrypted data.
742 * @param iv Initialization Vector to use.
744 * @return Size of the decrypted data, -1 if an error was encountered.
747 t_decrypt (struct CadetTunnel *t, void *dst, const void *src,
748 size_t size, uint32_t iv)
752 #if DUMP_KEYS_TO_STDERR
753 LOG (GNUNET_ERROR_TYPE_DEBUG, " t_decrypt with %s\n",
754 GNUNET_h2s ((struct GNUNET_HashCode *) &t->d_key));
756 if (CADET_TUNNEL_KEY_UNINITIALIZED == t->estate)
758 GNUNET_STATISTICS_update (stats, "# non decryptable data", 1, GNUNET_NO);
759 LOG (GNUNET_ERROR_TYPE_WARNING,
760 "got data on %s without a valid key\n",
762 GCT_debug (t, GNUNET_ERROR_TYPE_WARNING);
766 out_size = decrypt (&t->d_key, dst, src, size, iv);
773 * Decrypt and verify data with the appropriate tunnel key and verify that the
774 * data has not been altered since it was sent by the remote peer.
776 * @param t Tunnel whose key to use.
777 * @param dst Destination for the plaintext.
778 * @param src Source of the encrypted data. Can overlap with @c dst.
779 * @param size Size of the encrypted data.
780 * @param iv Initialization Vector to use.
781 * @param msg_hmac HMAC of the message, cannot be NULL.
783 * @return Size of the decrypted data, -1 if an error was encountered.
786 t_decrypt_and_validate (struct CadetTunnel *t,
787 void *dst, const void *src,
788 size_t size, uint32_t iv,
789 const struct GNUNET_CADET_Hash *msg_hmac)
791 struct GNUNET_CRYPTO_SymmetricSessionKey *key;
792 struct GNUNET_CADET_Hash hmac;
795 /* Try primary (newest) key */
797 decrypted_size = decrypt (key, dst, src, size, iv);
798 t_hmac (src, size, iv, key, &hmac);
799 if (0 == memcmp (msg_hmac, &hmac, sizeof (hmac)))
800 return decrypted_size;
802 /* If no key exchange is going on, we just failed */
803 if (NULL == t->kx_ctx)
805 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
806 "Failed checksum validation on tunnel %s with no KX\n",
808 GNUNET_STATISTICS_update (stats, "# wrong HMAC", 1, GNUNET_NO);
812 /* Try secondary (from previous KX period) key */
813 key = &t->kx_ctx->d_key_old;
814 decrypted_size = decrypt (key, dst, src, size, iv);
815 t_hmac (src, size, iv, key, &hmac);
816 if (0 == memcmp (msg_hmac, &hmac, sizeof (hmac)))
817 return decrypted_size;
819 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
820 "Failed checksum validation on tunnel %s with KX\n",
822 GNUNET_STATISTICS_update (stats, "# wrong HMAC", 1, GNUNET_NO);
828 * Create key material by doing ECDH on the local and remote ephemeral keys.
830 * @param key_material Where to store the key material.
831 * @param ephemeral_key Peer's public ephemeral key.
834 derive_key_material (struct GNUNET_HashCode *key_material,
835 const struct GNUNET_CRYPTO_EcdhePublicKey *ephemeral_key)
838 GNUNET_CRYPTO_ecc_ecdh (my_ephemeral_key,
848 * Create a symmetic key from the identities of both ends and the key material
851 * @param key Destination for the generated key.
852 * @param sender ID of the peer that will encrypt with @c key.
853 * @param receiver ID of the peer that will decrypt with @c key.
854 * @param key_material Hash created with ECDH with the ephemeral keys.
857 derive_symmertic (struct GNUNET_CRYPTO_SymmetricSessionKey *key,
858 const struct GNUNET_PeerIdentity *sender,
859 const struct GNUNET_PeerIdentity *receiver,
860 const struct GNUNET_HashCode *key_material)
862 const char salt[] = "CADET kx salt";
864 GNUNET_CRYPTO_kdf (key, sizeof (struct GNUNET_CRYPTO_SymmetricSessionKey),
866 key_material, sizeof (struct GNUNET_HashCode),
867 sender, sizeof (struct GNUNET_PeerIdentity),
868 receiver, sizeof (struct GNUNET_PeerIdentity),
874 * Derive the tunnel's keys using our own and the peer's ephemeral keys.
876 * @param t Tunnel for which to create the keys.
879 create_keys (struct CadetTunnel *t)
881 struct GNUNET_HashCode km;
883 derive_key_material (&km, &t->peers_ephemeral_key);
884 derive_symmertic (&t->e_key, &my_full_id, GCP_get_id (t->peer), &km);
885 derive_symmertic (&t->d_key, GCP_get_id (t->peer), &my_full_id, &km);
886 #if DUMP_KEYS_TO_STDERR
887 LOG (GNUNET_ERROR_TYPE_INFO, "ME: %s\n",
888 GNUNET_h2s ((struct GNUNET_HashCode *) &kx_msg.ephemeral_key));
889 LOG (GNUNET_ERROR_TYPE_INFO, "PE: %s\n",
890 GNUNET_h2s ((struct GNUNET_HashCode *) &t->peers_ephemeral_key));
891 LOG (GNUNET_ERROR_TYPE_INFO, "KM: %s\n", GNUNET_h2s (&km));
892 LOG (GNUNET_ERROR_TYPE_INFO, "EK: %s\n",
893 GNUNET_h2s ((struct GNUNET_HashCode *) &t->e_key));
894 LOG (GNUNET_ERROR_TYPE_INFO, "DK: %s\n",
895 GNUNET_h2s ((struct GNUNET_HashCode *) &t->d_key));
901 * Create a new Key eXchange context for the tunnel.
903 * If the old keys were verified, keep them for old traffic. Create a new KX
904 * timestamp and a new nonce.
906 * @param t Tunnel for which to create the KX ctx.
909 create_kx_ctx (struct CadetTunnel *t)
911 LOG (GNUNET_ERROR_TYPE_INFO, " new kx ctx for %s\n", GCT_2s (t));
913 if (NULL != t->kx_ctx)
915 if (GNUNET_SCHEDULER_NO_TASK != t->kx_ctx->finish_task)
917 LOG (GNUNET_ERROR_TYPE_INFO, " resetting exisiting finish task\n");
918 GNUNET_SCHEDULER_cancel (t->kx_ctx->finish_task);
919 t->kx_ctx->finish_task = GNUNET_SCHEDULER_NO_TASK;
924 t->kx_ctx = GNUNET_new (struct CadetTunnelKXCtx);
925 t->kx_ctx->challenge = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_NONCE,
929 if (CADET_TUNNEL_KEY_OK == t->estate)
931 LOG (GNUNET_ERROR_TYPE_INFO, " backing up keys\n");
932 t->kx_ctx->d_key_old = t->d_key;
933 t->kx_ctx->e_key_old = t->e_key;
936 LOG (GNUNET_ERROR_TYPE_INFO, " old keys not valid, not saving\n");
937 t->kx_ctx->rekey_start_time = GNUNET_TIME_absolute_get ();
943 * @brief Finish the Key eXchange and destroy the old keys.
945 * @param cls Closure (Tunnel for which to finish the KX).
946 * @param tc Task context.
949 finish_kx (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
951 struct CadetTunnel *t = cls;
953 LOG (GNUNET_ERROR_TYPE_INFO, "finish KX for %s\n", GCT_2s (t));
955 if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
957 LOG (GNUNET_ERROR_TYPE_INFO, " shutdown\n");
961 GNUNET_free (t->kx_ctx);
967 * Destroy a Key eXchange context for the tunnel. This function only schedules
968 * the destruction, the freeing of the memory (and clearing of old key material)
969 * happens after a delay!
971 * @param t Tunnel whose KX ctx to destroy.
974 destroy_kx_ctx (struct CadetTunnel *t)
976 struct GNUNET_TIME_Relative delay;
978 if (NULL == t->kx_ctx || GNUNET_SCHEDULER_NO_TASK != t->kx_ctx->finish_task)
981 if (is_key_null (&t->kx_ctx->e_key_old))
983 t->kx_ctx->finish_task = GNUNET_SCHEDULER_add_now (finish_kx, t);
987 delay = GNUNET_TIME_relative_divide (rekey_period, 4);
988 delay = GNUNET_TIME_relative_min (delay, GNUNET_TIME_UNIT_MINUTES);
990 t->kx_ctx->finish_task = GNUNET_SCHEDULER_add_delayed (delay, finish_kx, t);
996 * Pick a connection on which send the next data message.
998 * @param t Tunnel on which to send the message.
1000 * @return The connection on which to send the next message.
1002 static struct CadetConnection *
1003 tunnel_get_connection (struct CadetTunnel *t)
1005 struct CadetTConnection *iter;
1006 struct CadetConnection *best;
1008 unsigned int lowest_q;
1010 LOG (GNUNET_ERROR_TYPE_DEBUG, "tunnel_get_connection %s\n", GCT_2s (t));
1012 lowest_q = UINT_MAX;
1013 for (iter = t->connection_head; NULL != iter; iter = iter->next)
1015 LOG (GNUNET_ERROR_TYPE_DEBUG, " connection %s: %u\n",
1016 GCC_2s (iter->c), GCC_get_state (iter->c));
1017 if (CADET_CONNECTION_READY == GCC_get_state (iter->c))
1019 qn = GCC_get_qn (iter->c, GCC_is_origin (iter->c, GNUNET_YES));
1020 LOG (GNUNET_ERROR_TYPE_DEBUG, " q_n %u, \n", qn);
1028 LOG (GNUNET_ERROR_TYPE_DEBUG, " selected: connection %s\n", GCC_2s (best));
1034 * Callback called when a queued message is sent.
1036 * Calculates the average time and connection packet tracking.
1038 * @param cls Closure (TunnelQueue handle).
1039 * @param c Connection this message was on.
1040 * @param q Connection queue handle (unused).
1041 * @param type Type of message sent.
1042 * @param fwd Was this a FWD going message?
1043 * @param size Size of the message.
1046 tun_message_sent (void *cls,
1047 struct CadetConnection *c,
1048 struct CadetConnectionQueue *q,
1049 uint16_t type, int fwd, size_t size)
1051 struct CadetTunnelQueue *qt = cls;
1052 struct CadetTunnel *t;
1054 LOG (GNUNET_ERROR_TYPE_DEBUG, "tun_message_sent\n");
1056 GNUNET_assert (NULL != qt->cont);
1057 t = NULL == c ? NULL : GCC_get_tunnel (c);
1058 qt->cont (qt->cont_cls, t, qt, type, size);
1064 count_queued_data (const struct CadetTunnel *t)
1066 struct CadetTunnelDelayed *iter;
1069 for (count = 0, iter = t->tq_head; iter != NULL; iter = iter->next)
1076 * Delete a queued message: either was sent or the channel was destroyed
1077 * before the tunnel's key exchange had a chance to finish.
1079 * @param tqd Delayed queue handle.
1082 unqueue_data (struct CadetTunnelDelayed *tqd)
1084 GNUNET_CONTAINER_DLL_remove (tqd->t->tq_head, tqd->t->tq_tail, tqd);
1090 * Cache a message to be sent once tunnel is online.
1092 * @param t Tunnel to hold the message.
1093 * @param msg Message itself (copy will be made).
1095 static struct CadetTunnelDelayed *
1096 queue_data (struct CadetTunnel *t, const struct GNUNET_MessageHeader *msg)
1098 struct CadetTunnelDelayed *tqd;
1099 uint16_t size = ntohs (msg->size);
1101 LOG (GNUNET_ERROR_TYPE_DEBUG, "queue data on Tunnel %s\n", GCT_2s (t));
1103 if (GNUNET_YES == is_ready (t))
1109 tqd = GNUNET_malloc (sizeof (struct CadetTunnelDelayed) + size);
1112 memcpy (&tqd[1], msg, size);
1113 GNUNET_CONTAINER_DLL_insert_tail (t->tq_head, t->tq_tail, tqd);
1119 * Sends an already built message on a tunnel, encrypting it and
1120 * choosing the best connection.
1122 * @param message Message to send. Function modifies it.
1123 * @param t Tunnel on which this message is transmitted.
1124 * @param c Connection to use (autoselect if NULL).
1125 * @param force Force the tunnel to take the message (buffer overfill).
1126 * @param cont Continuation to call once message is really sent.
1127 * @param cont_cls Closure for @c cont.
1128 * @param existing_q In case this a transmission of previously queued data,
1129 * this should be TunnelQueue given to the client.
1132 * @return Handle to cancel message.
1133 * NULL if @c cont is NULL or an error happens and message is dropped.
1135 static struct CadetTunnelQueue *
1136 send_prebuilt_message (const struct GNUNET_MessageHeader *message,
1137 struct CadetTunnel *t, struct CadetConnection *c,
1138 int force, GCT_sent cont, void *cont_cls,
1139 struct CadetTunnelQueue *existing_q)
1141 struct CadetTunnelQueue *tq;
1142 struct GNUNET_CADET_Encrypted *msg;
1143 size_t size = ntohs (message->size);
1144 char cbuf[sizeof (struct GNUNET_CADET_Encrypted) + size];
1150 LOG (GNUNET_ERROR_TYPE_DEBUG, "GMT Send on Tunnel %s\n", GCT_2s (t));
1152 if (GNUNET_NO == is_ready (t))
1154 struct CadetTunnelDelayed *tqd;
1155 /* A non null existing_q indicates sending of queued data.
1156 * Should only happen after tunnel becomes ready.
1158 GNUNET_assert (NULL == existing_q);
1159 tqd = queue_data (t, message);
1162 tq = GNUNET_new (struct CadetTunnelQueue);
1166 tq->cont_cls = cont_cls;
1170 GNUNET_assert (GNUNET_NO == GCT_is_loopback (t));
1172 iv = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_NONCE, UINT32_MAX);
1173 msg = (struct GNUNET_CADET_Encrypted *) cbuf;
1174 msg->header.type = htons (GNUNET_MESSAGE_TYPE_CADET_ENCRYPTED);
1176 GNUNET_assert (t_encrypt (t, &msg[1], message, size, iv, GNUNET_NO) == size);
1177 t_hmac (&msg[1], size, iv, select_key (t), &msg->hmac);
1178 msg->header.size = htons (sizeof (struct GNUNET_CADET_Encrypted) + size);
1181 c = tunnel_get_connection (t);
1184 /* Why is tunnel 'ready'? Should have been queued! */
1185 if (GNUNET_SCHEDULER_NO_TASK != t->destroy_task)
1188 GCT_debug (t, GNUNET_ERROR_TYPE_WARNING);
1190 return NULL; /* Drop... */
1194 type = ntohs (message->type);
1197 case GNUNET_MESSAGE_TYPE_CADET_DATA:
1198 case GNUNET_MESSAGE_TYPE_CADET_DATA_ACK:
1199 if (GNUNET_MESSAGE_TYPE_CADET_DATA == type)
1200 mid = ntohl (((struct GNUNET_CADET_Data *) message)->mid);
1202 mid = ntohl (((struct GNUNET_CADET_DataACK *) message)->mid);
1204 case GNUNET_MESSAGE_TYPE_CADET_KEEPALIVE:
1205 case GNUNET_MESSAGE_TYPE_CADET_CHANNEL_CREATE:
1206 case GNUNET_MESSAGE_TYPE_CADET_CHANNEL_DESTROY:
1207 case GNUNET_MESSAGE_TYPE_CADET_CHANNEL_ACK:
1208 case GNUNET_MESSAGE_TYPE_CADET_CHANNEL_NACK:
1209 msg->cid = *GCC_get_id (c);
1210 msg->ttl = htonl (default_ttl);
1214 LOG (GNUNET_ERROR_TYPE_ERROR, "type %s not valid\n", GC_m2s (type));
1216 LOG (GNUNET_ERROR_TYPE_DEBUG, "type %s\n", GC_m2s (type));
1218 fwd = GCC_is_origin (c, GNUNET_YES);
1222 GNUNET_break (NULL == GCC_send_prebuilt_message (&msg->header, type, mid, c,
1223 fwd, force, NULL, NULL));
1226 if (NULL == existing_q)
1228 tq = GNUNET_new (struct CadetTunnelQueue); /* FIXME valgrind: leak*/
1235 tq->cq = GCC_send_prebuilt_message (&msg->header, type, mid, c, fwd, force,
1236 &tun_message_sent, tq);
1237 GNUNET_assert (NULL != tq->cq);
1239 tq->cont_cls = cont_cls;
1246 * Send all cached messages that we can, tunnel is online.
1248 * @param t Tunnel that holds the messages. Cannot be loopback.
1251 send_queued_data (struct CadetTunnel *t)
1253 struct CadetTunnelDelayed *tqd;
1254 struct CadetTunnelDelayed *next;
1257 LOG (GNUNET_ERROR_TYPE_INFO, "Send queued data, tunnel %s\n", GCT_2s (t));
1259 if (GCT_is_loopback (t))
1265 if (GNUNET_NO == is_ready (t))
1267 LOG (GNUNET_ERROR_TYPE_DEBUG, " not ready yet: %s/%s\n",
1268 estate2s (t->estate), cstate2s (t->cstate));
1272 room = GCT_get_connections_buffer (t);
1273 LOG (GNUNET_ERROR_TYPE_DEBUG, " buffer space: %u\n", room);
1274 LOG (GNUNET_ERROR_TYPE_DEBUG, " tq head: %p\n", t->tq_head);
1275 for (tqd = t->tq_head; NULL != tqd && room > 0; tqd = next)
1277 LOG (GNUNET_ERROR_TYPE_DEBUG, " sending queued data\n");
1280 send_prebuilt_message ((struct GNUNET_MessageHeader *) &tqd[1],
1281 tqd->t, NULL, GNUNET_YES,
1282 NULL != tqd->tq ? tqd->tq->cont : NULL,
1283 NULL != tqd->tq ? tqd->tq->cont_cls : NULL,
1287 LOG (GNUNET_ERROR_TYPE_DEBUG, "GCT_send_queued_data end\n", GCP_2s (t->peer));
1292 * Callback called when a queued message is sent.
1294 * @param cls Closure.
1295 * @param c Connection this message was on.
1296 * @param type Type of message sent.
1297 * @param fwd Was this a FWD going message?
1298 * @param size Size of the message.
1301 ephm_sent (void *cls,
1302 struct CadetConnection *c,
1303 struct CadetConnectionQueue *q,
1304 uint16_t type, int fwd, size_t size)
1306 struct CadetTunnel *t = cls;
1307 LOG (GNUNET_ERROR_TYPE_DEBUG, "ephm_sent %s\n", GC_m2s (type));
1312 * Callback called when a queued message is sent.
1314 * @param cls Closure.
1315 * @param c Connection this message was on.
1316 * @param type Type of message sent.
1317 * @param fwd Was this a FWD going message?
1318 * @param size Size of the message.
1321 pong_sent (void *cls,
1322 struct CadetConnection *c,
1323 struct CadetConnectionQueue *q,
1324 uint16_t type, int fwd, size_t size)
1326 struct CadetTunnel *t = cls;
1327 LOG (GNUNET_ERROR_TYPE_DEBUG, "pong_sent %s\n", GC_m2s (type));
1333 * Sends key exchange message on a tunnel, choosing the best connection.
1334 * Should not be called on loopback tunnels.
1336 * @param t Tunnel on which this message is transmitted.
1337 * @param message Message to send. Function modifies it.
1339 * @return Handle to the message in the connection queue.
1341 static struct CadetConnectionQueue *
1342 send_kx (struct CadetTunnel *t,
1343 const struct GNUNET_MessageHeader *message)
1345 struct CadetConnection *c;
1346 struct GNUNET_CADET_KX *msg;
1347 size_t size = ntohs (message->size);
1348 char cbuf[sizeof (struct GNUNET_CADET_KX) + size];
1353 LOG (GNUNET_ERROR_TYPE_DEBUG, "GMT KX on Tunnel %s\n", GCT_2s (t));
1355 /* Avoid loopback. */
1356 if (GCT_is_loopback (t))
1358 LOG (GNUNET_ERROR_TYPE_DEBUG, " loopback!\n");
1362 type = ntohs (message->type);
1364 /* Even if tunnel is being destroyed, send anyway.
1365 * Could be a response to a rekey initiated by remote peer,
1366 * who is trying to create a new channel!
1369 /* Must have a connection, or be looking for one. */
1370 if (NULL == t->connection_head)
1372 if (CADET_TUNNEL_SEARCHING != t->cstate)
1374 LOG (GNUNET_ERROR_TYPE_ERROR, "\n\n\n");
1376 LOG (GNUNET_ERROR_TYPE_ERROR, "no connection, sending %s\n", GC_m2s (type));
1377 GCT_debug (t, GNUNET_ERROR_TYPE_ERROR);
1378 GCP_debug (t->peer, GNUNET_ERROR_TYPE_ERROR);
1379 LOG (GNUNET_ERROR_TYPE_ERROR, "\n\n\n");
1384 msg = (struct GNUNET_CADET_KX *) cbuf;
1385 msg->header.type = htons (GNUNET_MESSAGE_TYPE_CADET_KX);
1386 msg->header.size = htons (sizeof (struct GNUNET_CADET_KX) + size);
1387 c = tunnel_get_connection (t);
1390 if (GNUNET_SCHEDULER_NO_TASK == t->destroy_task
1391 && CADET_TUNNEL_READY == t->cstate)
1394 GCT_debug (t, GNUNET_ERROR_TYPE_ERROR);
1400 case GNUNET_MESSAGE_TYPE_CADET_KX_EPHEMERAL:
1401 GNUNET_assert (NULL == t->ephm_h);
1403 memcpy (&msg[1], message, size);
1405 case GNUNET_MESSAGE_TYPE_CADET_KX_PONG:
1406 GNUNET_assert (NULL == t->pong_h);
1408 memcpy (&msg[1], message, size);
1412 LOG (GNUNET_ERROR_TYPE_DEBUG, "unkown type %s\n", GC_m2s (type));
1416 fwd = GCC_is_origin (t->connection_head->c, GNUNET_YES);
1418 return GCC_send_prebuilt_message (&msg->header, type, 0, c,
1425 * Send the ephemeral key on a tunnel.
1427 * @param t Tunnel on which to send the key.
1430 send_ephemeral (struct CadetTunnel *t)
1432 LOG (GNUNET_ERROR_TYPE_INFO, "===> EPHM for %s\n", GCT_2s (t));
1433 if (NULL != t->ephm_h)
1435 LOG (GNUNET_ERROR_TYPE_INFO, " already queued\n");
1439 kx_msg.sender_status = htonl (t->estate);
1440 kx_msg.iv = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_NONCE, UINT32_MAX);
1441 kx_msg.nonce = t->kx_ctx->challenge;
1442 LOG (GNUNET_ERROR_TYPE_DEBUG, " send nonce c %u\n", kx_msg.nonce);
1443 t_encrypt (t, &kx_msg.nonce, &kx_msg.nonce,
1444 ping_encryption_size(), kx_msg.iv, GNUNET_YES);
1445 LOG (GNUNET_ERROR_TYPE_DEBUG, " send nonce e %u\n", kx_msg.nonce);
1446 t->ephm_h = send_kx (t, &kx_msg.header);
1451 * Send a pong message on a tunnel.
1453 * @param t Tunnel on which to send the pong.
1454 * @param challenge Value sent in the ping that we have to send back.
1457 send_pong (struct CadetTunnel *t, uint32_t challenge)
1459 struct GNUNET_CADET_KX_Pong msg;
1461 LOG (GNUNET_ERROR_TYPE_INFO, "===> PONG for %s\n", GCT_2s (t));
1462 if (NULL != t->pong_h)
1464 LOG (GNUNET_ERROR_TYPE_INFO, " already queued\n");
1467 msg.header.size = htons (sizeof (msg));
1468 msg.header.type = htons (GNUNET_MESSAGE_TYPE_CADET_KX_PONG);
1469 msg.iv = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_NONCE, UINT32_MAX);
1470 msg.nonce = challenge;
1471 LOG (GNUNET_ERROR_TYPE_DEBUG, " sending %u\n", msg.nonce);
1472 t_encrypt (t, &msg.nonce, &msg.nonce,
1473 sizeof (msg.nonce), msg.iv, GNUNET_YES);
1474 LOG (GNUNET_ERROR_TYPE_DEBUG, " e sending %u\n", msg.nonce);
1476 t->pong_h = send_kx (t, &msg.header);
1481 * Initiate a rekey with the remote peer.
1483 * @param cls Closure (tunnel).
1484 * @param tc TaskContext.
1487 rekey_tunnel (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
1489 struct CadetTunnel *t = cls;
1491 t->rekey_task = GNUNET_SCHEDULER_NO_TASK;
1493 LOG (GNUNET_ERROR_TYPE_INFO, "Re-key Tunnel %s\n", GCT_2s (t));
1494 if (NULL != tc && 0 != (GNUNET_SCHEDULER_REASON_SHUTDOWN & tc->reason))
1497 GNUNET_assert (NULL != t->kx_ctx);
1498 struct GNUNET_TIME_Relative duration;
1500 duration = GNUNET_TIME_absolute_get_duration (t->kx_ctx->rekey_start_time);
1501 LOG (GNUNET_ERROR_TYPE_DEBUG, " kx started %s ago\n",
1502 GNUNET_STRINGS_relative_time_to_string (duration, GNUNET_YES));
1504 // FIXME make duration of old keys configurable
1505 if (duration.rel_value_us >= GNUNET_TIME_UNIT_MINUTES.rel_value_us)
1507 LOG (GNUNET_ERROR_TYPE_DEBUG, " deleting old keys\n");
1508 memset (&t->kx_ctx->d_key_old, 0, sizeof (t->kx_ctx->d_key_old));
1509 memset (&t->kx_ctx->e_key_old, 0, sizeof (t->kx_ctx->e_key_old));
1516 case CADET_TUNNEL_KEY_UNINITIALIZED:
1517 GCT_change_estate (t, CADET_TUNNEL_KEY_SENT);
1520 case CADET_TUNNEL_KEY_SENT:
1523 case CADET_TUNNEL_KEY_OK:
1525 * - state should have changed during rekey_iterator
1526 * - task should have been canceled at pong_handle
1529 GCT_change_estate (t, CADET_TUNNEL_KEY_REKEY);
1532 case CADET_TUNNEL_KEY_PING:
1533 case CADET_TUNNEL_KEY_REKEY:
1537 LOG (GNUNET_ERROR_TYPE_DEBUG, "Unexpected state %u\n", t->estate);
1540 // FIXME exponential backoff
1541 struct GNUNET_TIME_Relative delay;
1543 delay = GNUNET_TIME_relative_divide (rekey_period, 16);
1544 delay = GNUNET_TIME_relative_min (delay, REKEY_WAIT);
1545 LOG (GNUNET_ERROR_TYPE_DEBUG, " next call in %s\n",
1546 GNUNET_STRINGS_relative_time_to_string (delay, GNUNET_YES));
1547 t->rekey_task = GNUNET_SCHEDULER_add_delayed (delay, &rekey_tunnel, t);
1552 * Our ephemeral key has changed, create new session key on all tunnels.
1554 * Each tunnel will start the Key Exchange with a random delay between
1555 * 0 and number_of_tunnels*100 milliseconds, so there are 10 key exchanges
1556 * per second, on average.
1558 * @param cls Closure (size of the hashmap).
1559 * @param key Current public key.
1560 * @param value Value in the hash map (tunnel).
1562 * @return #GNUNET_YES, so we should continue to iterate,
1565 rekey_iterator (void *cls,
1566 const struct GNUNET_PeerIdentity *key,
1569 struct CadetTunnel *t = value;
1570 struct GNUNET_TIME_Relative delay;
1571 long n = (long) cls;
1574 if (GNUNET_SCHEDULER_NO_TASK != t->rekey_task)
1577 if (GNUNET_YES == GCT_is_loopback (t))
1580 r = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK, (uint32_t) n * 100);
1581 delay = GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MILLISECONDS, r);
1582 t->rekey_task = GNUNET_SCHEDULER_add_delayed (delay, &rekey_tunnel, t);
1584 GCT_change_estate (t, CADET_TUNNEL_KEY_REKEY);
1591 * Create a new ephemeral key and key message, schedule next rekeying.
1593 * @param cls Closure (unused).
1594 * @param tc TaskContext.
1597 rekey (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
1599 struct GNUNET_TIME_Absolute time;
1602 rekey_task = GNUNET_SCHEDULER_NO_TASK;
1604 if (0 != (GNUNET_SCHEDULER_REASON_SHUTDOWN & tc->reason))
1607 GNUNET_free_non_null (my_ephemeral_key);
1608 my_ephemeral_key = GNUNET_CRYPTO_ecdhe_key_create ();
1610 time = GNUNET_TIME_absolute_get ();
1611 kx_msg.creation_time = GNUNET_TIME_absolute_hton (time);
1612 time = GNUNET_TIME_absolute_add (time, rekey_period);
1613 time = GNUNET_TIME_absolute_add (time, GNUNET_TIME_UNIT_MINUTES);
1614 kx_msg.expiration_time = GNUNET_TIME_absolute_hton (time);
1615 GNUNET_CRYPTO_ecdhe_key_get_public (my_ephemeral_key, &kx_msg.ephemeral_key);
1616 LOG (GNUNET_ERROR_TYPE_INFO, "GLOBAL RE-KEY, NEW EPHM: %s\n",
1617 GNUNET_h2s ((struct GNUNET_HashCode *) &kx_msg.ephemeral_key));
1619 GNUNET_assert (GNUNET_OK ==
1620 GNUNET_CRYPTO_eddsa_sign (my_private_key,
1622 &kx_msg.signature));
1624 n = (long) GNUNET_CONTAINER_multipeermap_size (tunnels);
1625 GNUNET_CONTAINER_multipeermap_iterate (tunnels, &rekey_iterator, (void *) n);
1627 rekey_task = GNUNET_SCHEDULER_add_delayed (rekey_period, &rekey, NULL);
1632 * Called only on shutdown, destroy every tunnel.
1634 * @param cls Closure (unused).
1635 * @param key Current public key.
1636 * @param value Value in the hash map (tunnel).
1638 * @return #GNUNET_YES, so we should continue to iterate,
1641 destroy_iterator (void *cls,
1642 const struct GNUNET_PeerIdentity *key,
1645 struct CadetTunnel *t = value;
1647 LOG (GNUNET_ERROR_TYPE_DEBUG, "GCT_shutdown destroying tunnel at %p\n", t);
1654 * Notify remote peer that we don't know a channel he is talking about,
1655 * probably CHANNEL_DESTROY was missed.
1657 * @param t Tunnel on which to notify.
1658 * @param gid ID of the channel.
1661 send_channel_destroy (struct CadetTunnel *t, unsigned int gid)
1663 struct GNUNET_CADET_ChannelManage msg;
1665 msg.header.type = htons (GNUNET_MESSAGE_TYPE_CADET_CHANNEL_DESTROY);
1666 msg.header.size = htons (sizeof (msg));
1667 msg.chid = htonl (gid);
1669 LOG (GNUNET_ERROR_TYPE_DEBUG,
1670 "WARNING destroying unknown channel %u on tunnel %s\n",
1672 send_prebuilt_message (&msg.header, t, NULL, GNUNET_YES, NULL, NULL, NULL);
1677 * Demultiplex data per channel and call appropriate channel handler.
1679 * @param t Tunnel on which the data came.
1680 * @param msg Data message.
1681 * @param fwd Is this message fwd? This only is meaningful in loopback channels.
1682 * #GNUNET_YES if message is FWD on the respective channel (loopback)
1683 * #GNUNET_NO if message is BCK on the respective channel (loopback)
1684 * #GNUNET_SYSERR if message on a one-ended channel (remote)
1687 handle_data (struct CadetTunnel *t,
1688 const struct GNUNET_CADET_Data *msg,
1691 struct CadetChannel *ch;
1695 size = ntohs (msg->header.size);
1697 sizeof (struct GNUNET_CADET_Data) +
1698 sizeof (struct GNUNET_MessageHeader))
1703 LOG (GNUNET_ERROR_TYPE_DEBUG, " payload of type %s\n",
1704 GC_m2s (ntohs (msg[1].header.type)));
1707 ch = GCT_get_channel (t, ntohl (msg->chid));
1710 GNUNET_STATISTICS_update (stats, "# data on unknown channel",
1712 LOG (GNUNET_ERROR_TYPE_DEBUG, "WARNING channel 0x%X unknown\n",
1714 send_channel_destroy (t, ntohl (msg->chid));
1718 GCCH_handle_data (ch, msg, fwd);
1723 * Demultiplex data ACKs per channel and update appropriate channel buffer info.
1725 * @param t Tunnel on which the DATA ACK came.
1726 * @param msg DATA ACK message.
1727 * @param fwd Is this message fwd? This only is meaningful in loopback channels.
1728 * #GNUNET_YES if message is FWD on the respective channel (loopback)
1729 * #GNUNET_NO if message is BCK on the respective channel (loopback)
1730 * #GNUNET_SYSERR if message on a one-ended channel (remote)
1733 handle_data_ack (struct CadetTunnel *t,
1734 const struct GNUNET_CADET_DataACK *msg,
1737 struct CadetChannel *ch;
1741 size = ntohs (msg->header.size);
1742 if (size != sizeof (struct GNUNET_CADET_DataACK))
1749 ch = GCT_get_channel (t, ntohl (msg->chid));
1752 GNUNET_STATISTICS_update (stats, "# data ack on unknown channel",
1754 LOG (GNUNET_ERROR_TYPE_DEBUG, "WARNING channel %u unknown\n",
1759 GCCH_handle_data_ack (ch, msg, fwd);
1764 * Handle channel create.
1766 * @param t Tunnel on which the data came.
1767 * @param msg Data message.
1770 handle_ch_create (struct CadetTunnel *t,
1771 const struct GNUNET_CADET_ChannelCreate *msg)
1773 struct CadetChannel *ch;
1777 size = ntohs (msg->header.size);
1778 if (size != sizeof (struct GNUNET_CADET_ChannelCreate))
1785 ch = GCT_get_channel (t, ntohl (msg->chid));
1786 if (NULL != ch && ! GCT_is_loopback (t))
1788 /* Probably a retransmission, safe to ignore */
1789 LOG (GNUNET_ERROR_TYPE_DEBUG, " already exists...\n");
1791 ch = GCCH_handle_create (t, msg);
1793 GCT_add_channel (t, ch);
1799 * Handle channel NACK: check correctness and call channel handler for NACKs.
1801 * @param t Tunnel on which the NACK came.
1802 * @param msg NACK message.
1805 handle_ch_nack (struct CadetTunnel *t,
1806 const struct GNUNET_CADET_ChannelManage *msg)
1808 struct CadetChannel *ch;
1812 size = ntohs (msg->header.size);
1813 if (size != sizeof (struct GNUNET_CADET_ChannelManage))
1820 ch = GCT_get_channel (t, ntohl (msg->chid));
1823 GNUNET_STATISTICS_update (stats, "# channel NACK on unknown channel",
1825 LOG (GNUNET_ERROR_TYPE_DEBUG, "WARNING channel %u unknown\n",
1830 GCCH_handle_nack (ch);
1835 * Handle a CHANNEL ACK (SYNACK/ACK).
1837 * @param t Tunnel on which the CHANNEL ACK came.
1838 * @param msg CHANNEL ACK message.
1839 * @param fwd Is this message fwd? This only is meaningful in loopback channels.
1840 * #GNUNET_YES if message is FWD on the respective channel (loopback)
1841 * #GNUNET_NO if message is BCK on the respective channel (loopback)
1842 * #GNUNET_SYSERR if message on a one-ended channel (remote)
1845 handle_ch_ack (struct CadetTunnel *t,
1846 const struct GNUNET_CADET_ChannelManage *msg,
1849 struct CadetChannel *ch;
1853 size = ntohs (msg->header.size);
1854 if (size != sizeof (struct GNUNET_CADET_ChannelManage))
1861 ch = GCT_get_channel (t, ntohl (msg->chid));
1864 GNUNET_STATISTICS_update (stats, "# channel ack on unknown channel",
1866 LOG (GNUNET_ERROR_TYPE_DEBUG, "WARNING channel %u unknown\n",
1871 GCCH_handle_ack (ch, msg, fwd);
1876 * Handle a channel destruction message.
1878 * @param t Tunnel on which the message came.
1879 * @param msg Channel destroy message.
1880 * @param fwd Is this message fwd? This only is meaningful in loopback channels.
1881 * #GNUNET_YES if message is FWD on the respective channel (loopback)
1882 * #GNUNET_NO if message is BCK on the respective channel (loopback)
1883 * #GNUNET_SYSERR if message on a one-ended channel (remote)
1886 handle_ch_destroy (struct CadetTunnel *t,
1887 const struct GNUNET_CADET_ChannelManage *msg,
1890 struct CadetChannel *ch;
1894 size = ntohs (msg->header.size);
1895 if (size != sizeof (struct GNUNET_CADET_ChannelManage))
1902 ch = GCT_get_channel (t, ntohl (msg->chid));
1905 /* Probably a retransmission, safe to ignore */
1909 GCCH_handle_destroy (ch, msg, fwd);
1914 * The peer's ephemeral key has changed: update the symmetrical keys.
1916 * @param t Tunnel this message came on.
1917 * @param msg Key eXchange message.
1920 handle_ephemeral (struct CadetTunnel *t,
1921 const struct GNUNET_CADET_KX_Ephemeral *msg)
1923 LOG (GNUNET_ERROR_TYPE_INFO, "<=== EPHM for %s\n", GCT_2s (t));
1925 if (GNUNET_OK != check_ephemeral (t, msg))
1927 GNUNET_break_op (0);
1932 * If the key is different from what we know, derive the new E/D keys.
1933 * Else destroy the rekey ctx (duplicate EPHM after successful KX).
1935 if (0 != memcmp (&t->peers_ephemeral_key, &msg->ephemeral_key,
1936 sizeof (msg->ephemeral_key)))
1938 #if DUMP_KEYS_TO_STDERR
1939 LOG (GNUNET_ERROR_TYPE_INFO, "OLD: %s\n",
1940 GNUNET_h2s ((struct GNUNET_HashCode *) &t->peers_ephemeral_key));
1941 LOG (GNUNET_ERROR_TYPE_INFO, "NEW: %s\n",
1942 GNUNET_h2s ((struct GNUNET_HashCode *) &msg->ephemeral_key));
1944 t->peers_ephemeral_key = msg->ephemeral_key;
1948 if (CADET_TUNNEL_KEY_OK == t->estate)
1950 GCT_change_estate (t, CADET_TUNNEL_KEY_REKEY);
1952 if (GNUNET_SCHEDULER_NO_TASK != t->rekey_task)
1953 GNUNET_SCHEDULER_cancel (t->rekey_task);
1954 t->rekey_task = GNUNET_SCHEDULER_add_now (rekey_tunnel, t);
1956 if (CADET_TUNNEL_KEY_SENT == t->estate)
1958 LOG (GNUNET_ERROR_TYPE_DEBUG, " our key was sent, sending challenge\n");
1960 GCT_change_estate (t, CADET_TUNNEL_KEY_PING);
1963 if (CADET_TUNNEL_KEY_UNINITIALIZED != ntohl(msg->sender_status))
1967 LOG (GNUNET_ERROR_TYPE_DEBUG, " recv nonce e %u\n", msg->nonce);
1968 t_decrypt (t, &nonce, &msg->nonce, ping_encryption_size (), msg->iv);
1969 LOG (GNUNET_ERROR_TYPE_DEBUG, " recv nonce c %u\n", nonce);
1970 send_pong (t, nonce);
1976 * Peer has answer to our challenge.
1977 * If answer is successful, consider the key exchange finished and clean
1978 * up all related state.
1980 * @param t Tunnel this message came on.
1981 * @param msg Key eXchange Pong message.
1984 handle_pong (struct CadetTunnel *t,
1985 const struct GNUNET_CADET_KX_Pong *msg)
1989 LOG (GNUNET_ERROR_TYPE_INFO, "<=== PONG for %s\n", GCT_2s (t));
1990 if (GNUNET_SCHEDULER_NO_TASK == t->rekey_task)
1992 GNUNET_STATISTICS_update (stats, "# duplicate PONG messages", 1, GNUNET_NO);
1995 if (NULL == t->kx_ctx)
1997 GNUNET_STATISTICS_update (stats, "# stray PONG messages", 1, GNUNET_NO);
2001 t_decrypt (t, &challenge, &msg->nonce, sizeof (uint32_t), msg->iv);
2002 if (challenge != t->kx_ctx->challenge)
2004 LOG (GNUNET_ERROR_TYPE_WARNING, "Wrong PONG challenge on %s\n", GCT_2s (t));
2005 LOG (GNUNET_ERROR_TYPE_DEBUG, "PONG: %u (e: %u). Expected: %u.\n",
2006 challenge, msg->nonce, t->kx_ctx->challenge);
2010 GNUNET_SCHEDULER_cancel (t->rekey_task);
2011 t->rekey_task = GNUNET_SCHEDULER_NO_TASK;
2013 /* Don't free the old keys right away, but after a delay.
2014 * Rationale: the KX could have happened over a very fast connection,
2015 * with payload traffic still signed with the old key stuck in a slower
2017 * Don't keep the keys longer than 1/4 the rekey period, and no longer than
2021 GCT_change_estate (t, CADET_TUNNEL_KEY_OK);
2026 * Demultiplex by message type and call appropriate handler for a message
2027 * towards a channel of a local tunnel.
2029 * @param t Tunnel this message came on.
2030 * @param msgh Message header.
2031 * @param fwd Is this message fwd? This only is meaningful in loopback channels.
2032 * #GNUNET_YES if message is FWD on the respective channel (loopback)
2033 * #GNUNET_NO if message is BCK on the respective channel (loopback)
2034 * #GNUNET_SYSERR if message on a one-ended channel (remote)
2037 handle_decrypted (struct CadetTunnel *t,
2038 const struct GNUNET_MessageHeader *msgh,
2043 type = ntohs (msgh->type);
2044 LOG (GNUNET_ERROR_TYPE_INFO, "<=== %s on %s\n", GC_m2s (type), GCT_2s (t));
2048 case GNUNET_MESSAGE_TYPE_CADET_KEEPALIVE:
2049 /* Do nothing, connection aleady got updated. */
2050 GNUNET_STATISTICS_update (stats, "# keepalives received", 1, GNUNET_NO);
2053 case GNUNET_MESSAGE_TYPE_CADET_DATA:
2054 /* Don't send hop ACK, wait for client to ACK */
2055 handle_data (t, (struct GNUNET_CADET_Data *) msgh, fwd);
2058 case GNUNET_MESSAGE_TYPE_CADET_DATA_ACK:
2059 handle_data_ack (t, (struct GNUNET_CADET_DataACK *) msgh, fwd);
2062 case GNUNET_MESSAGE_TYPE_CADET_CHANNEL_CREATE:
2063 handle_ch_create (t,
2064 (struct GNUNET_CADET_ChannelCreate *) msgh);
2067 case GNUNET_MESSAGE_TYPE_CADET_CHANNEL_NACK:
2069 (struct GNUNET_CADET_ChannelManage *) msgh);
2072 case GNUNET_MESSAGE_TYPE_CADET_CHANNEL_ACK:
2074 (struct GNUNET_CADET_ChannelManage *) msgh,
2078 case GNUNET_MESSAGE_TYPE_CADET_CHANNEL_DESTROY:
2079 handle_ch_destroy (t,
2080 (struct GNUNET_CADET_ChannelManage *) msgh,
2085 GNUNET_break_op (0);
2086 LOG (GNUNET_ERROR_TYPE_WARNING,
2087 "end-to-end message not known (%u)\n",
2088 ntohs (msgh->type));
2089 GCT_debug (t, GNUNET_ERROR_TYPE_WARNING);
2093 /******************************************************************************/
2094 /******************************** API ***********************************/
2095 /******************************************************************************/
2098 * Decrypt and demultiplex by message type. Call appropriate handler
2099 * for every message.
2101 * @param t Tunnel this message came on.
2102 * @param msg Encrypted message.
2105 GCT_handle_encrypted (struct CadetTunnel *t,
2106 const struct GNUNET_CADET_Encrypted *msg)
2108 size_t size = ntohs (msg->header.size);
2109 size_t payload_size = size - sizeof (struct GNUNET_CADET_Encrypted);
2111 char cbuf [payload_size];
2112 struct GNUNET_MessageHeader *msgh;
2115 decrypted_size = t_decrypt_and_validate (t, cbuf, &msg[1], payload_size,
2116 msg->iv, &msg->hmac);
2118 if (-1 == decrypted_size)
2120 GNUNET_break_op (0);
2125 while (off < decrypted_size)
2129 msgh = (struct GNUNET_MessageHeader *) &cbuf[off];
2130 msize = ntohs (msgh->size);
2131 if (msize < sizeof (struct GNUNET_MessageHeader))
2133 GNUNET_break_op (0);
2136 handle_decrypted (t, msgh, GNUNET_SYSERR);
2143 * Demultiplex an encapsulated KX message by message type.
2145 * @param t Tunnel on which the message came.
2146 * @param message Payload of KX message.
2149 GCT_handle_kx (struct CadetTunnel *t,
2150 const struct GNUNET_MessageHeader *message)
2154 type = ntohs (message->type);
2155 LOG (GNUNET_ERROR_TYPE_DEBUG, "kx message received\n", type);
2158 case GNUNET_MESSAGE_TYPE_CADET_KX_EPHEMERAL:
2159 handle_ephemeral (t, (struct GNUNET_CADET_KX_Ephemeral *) message);
2162 case GNUNET_MESSAGE_TYPE_CADET_KX_PONG:
2163 handle_pong (t, (struct GNUNET_CADET_KX_Pong *) message);
2167 GNUNET_break_op (0);
2168 LOG (GNUNET_ERROR_TYPE_DEBUG, "kx message not known (%u)\n", type);
2174 * Initialize the tunnel subsystem.
2176 * @param c Configuration handle.
2177 * @param key ECC private key, to derive all other keys and do crypto.
2180 GCT_init (const struct GNUNET_CONFIGURATION_Handle *c,
2181 const struct GNUNET_CRYPTO_EddsaPrivateKey *key)
2183 int expected_overhead;
2185 LOG (GNUNET_ERROR_TYPE_DEBUG, "init\n");
2187 expected_overhead = 0;
2188 expected_overhead += sizeof (struct GNUNET_CADET_Encrypted);
2189 expected_overhead += sizeof (struct GNUNET_CADET_Data);
2190 expected_overhead += sizeof (struct GNUNET_CADET_ACK);
2191 GNUNET_assert (GNUNET_CONSTANTS_CADET_P2P_OVERHEAD == expected_overhead);
2194 GNUNET_CONFIGURATION_get_value_number (c, "CADET", "DEFAULT_TTL",
2197 GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_WARNING,
2198 "CADET", "DEFAULT_TTL", "USING DEFAULT");
2202 GNUNET_CONFIGURATION_get_value_time (c, "CADET", "REKEY_PERIOD",
2205 rekey_period = GNUNET_TIME_UNIT_DAYS;
2208 my_private_key = key;
2209 kx_msg.header.size = htons (sizeof (kx_msg));
2210 kx_msg.header.type = htons (GNUNET_MESSAGE_TYPE_CADET_KX_EPHEMERAL);
2211 kx_msg.purpose.purpose = htonl (GNUNET_SIGNATURE_PURPOSE_CADET_KX);
2212 kx_msg.purpose.size = htonl (ephemeral_purpose_size ());
2213 kx_msg.origin_identity = my_full_id;
2214 rekey_task = GNUNET_SCHEDULER_add_now (&rekey, NULL);
2216 tunnels = GNUNET_CONTAINER_multipeermap_create (128, GNUNET_YES);
2221 * Shut down the tunnel subsystem.
2226 if (GNUNET_SCHEDULER_NO_TASK != rekey_task)
2228 GNUNET_SCHEDULER_cancel (rekey_task);
2229 rekey_task = GNUNET_SCHEDULER_NO_TASK;
2231 GNUNET_CONTAINER_multipeermap_iterate (tunnels, &destroy_iterator, NULL);
2232 GNUNET_CONTAINER_multipeermap_destroy (tunnels);
2239 * @param destination Peer this tunnel is towards.
2241 struct CadetTunnel *
2242 GCT_new (struct CadetPeer *destination)
2244 struct CadetTunnel *t;
2246 t = GNUNET_new (struct CadetTunnel);
2248 t->peer = destination;
2251 GNUNET_CONTAINER_multipeermap_put (tunnels, GCP_get_id (destination), t,
2252 GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_FAST))
2263 * Change the tunnel's connection state.
2265 * @param t Tunnel whose connection state to change.
2266 * @param cstate New connection state.
2269 GCT_change_cstate (struct CadetTunnel* t, enum CadetTunnelCState cstate)
2273 LOG (GNUNET_ERROR_TYPE_DEBUG, "Tunnel %s cstate %s => %s\n",
2274 GCP_2s (t->peer), cstate2s (t->cstate), cstate2s (cstate));
2275 if (myid != GCP_get_short_id (t->peer) &&
2276 CADET_TUNNEL_READY != t->cstate &&
2277 CADET_TUNNEL_READY == cstate)
2280 if (CADET_TUNNEL_KEY_OK == t->estate)
2282 LOG (GNUNET_ERROR_TYPE_DEBUG, " cstate triggered send queued data\n");
2283 send_queued_data (t);
2285 else if (CADET_TUNNEL_KEY_UNINITIALIZED == t->estate)
2287 LOG (GNUNET_ERROR_TYPE_DEBUG, " cstate triggered rekey\n");
2288 if (GNUNET_SCHEDULER_NO_TASK != t->rekey_task)
2289 GNUNET_SCHEDULER_cancel (t->rekey_task);
2291 rekey_tunnel (t, NULL);
2296 if (CADET_TUNNEL_READY == cstate
2297 && CONNECTIONS_PER_TUNNEL <= GCT_count_connections (t))
2299 LOG (GNUNET_ERROR_TYPE_DEBUG, " cstate triggered stop dht\n");
2300 GCP_stop_search (t->peer);
2306 * Change the tunnel encryption state.
2308 * @param t Tunnel whose encryption state to change, or NULL.
2309 * @param state New encryption state.
2312 GCT_change_estate (struct CadetTunnel* t, enum CadetTunnelEState state)
2314 enum CadetTunnelEState old;
2321 LOG (GNUNET_ERROR_TYPE_DEBUG, "Tunnel %s estate was %s\n",
2322 GCP_2s (t->peer), estate2s (old));
2323 LOG (GNUNET_ERROR_TYPE_DEBUG, "Tunnel %s estate is now %s\n",
2324 GCP_2s (t->peer), estate2s (t->estate));
2326 /* Send queued data if enc state changes to OK */
2327 if (myid != GCP_get_short_id (t->peer) &&
2328 CADET_TUNNEL_KEY_OK != old && CADET_TUNNEL_KEY_OK == t->estate)
2330 send_queued_data (t);
2336 * @brief Check if tunnel has too many connections, and remove one if necessary.
2338 * Currently this means the newest connection, unless it is a direct one.
2339 * Implemented as a task to avoid freeing a connection that is in the middle
2340 * of being created/processed.
2342 * @param cls Closure (Tunnel to check).
2343 * @param tc Task context.
2346 trim_connections (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
2348 struct CadetTunnel *t = cls;
2350 t->trim_connections_task = GNUNET_SCHEDULER_NO_TASK;
2352 if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
2355 if (GCT_count_connections (t) > 2 * CONNECTIONS_PER_TUNNEL)
2357 struct CadetTConnection *iter;
2358 struct CadetTConnection *c;
2360 for (c = iter = t->connection_head; NULL != iter; iter = iter->next)
2362 if ((iter->created.abs_value_us > c->created.abs_value_us)
2363 && GNUNET_NO == GCC_is_direct (iter->c))
2370 LOG (GNUNET_ERROR_TYPE_DEBUG, "Too many connections on tunnel %s\n",
2372 LOG (GNUNET_ERROR_TYPE_DEBUG, "Destroying connection %s\n",
2385 * Add a connection to a tunnel.
2388 * @param c Connection.
2391 GCT_add_connection (struct CadetTunnel *t, struct CadetConnection *c)
2393 struct CadetTConnection *aux;
2395 GNUNET_assert (NULL != c);
2397 LOG (GNUNET_ERROR_TYPE_DEBUG, "add connection %s\n", GCC_2s (c));
2398 LOG (GNUNET_ERROR_TYPE_DEBUG, " to tunnel %s\n", GCT_2s (t));
2399 for (aux = t->connection_head; aux != NULL; aux = aux->next)
2403 aux = GNUNET_new (struct CadetTConnection);
2405 aux->created = GNUNET_TIME_absolute_get ();
2407 GNUNET_CONTAINER_DLL_insert (t->connection_head, t->connection_tail, aux);
2409 if (CADET_TUNNEL_SEARCHING == t->cstate)
2410 GCT_change_estate (t, CADET_TUNNEL_WAITING);
2412 if (GNUNET_SCHEDULER_NO_TASK != t->trim_connections_task)
2413 t->trim_connections_task = GNUNET_SCHEDULER_add_now (&trim_connections, t);
2418 * Remove a connection from a tunnel.
2421 * @param c Connection.
2424 GCT_remove_connection (struct CadetTunnel *t,
2425 struct CadetConnection *c)
2427 struct CadetTConnection *aux;
2428 struct CadetTConnection *next;
2431 LOG (GNUNET_ERROR_TYPE_DEBUG, "Removing connection %s from tunnel %s\n",
2432 GCC_2s (c), GCT_2s (t));
2433 for (aux = t->connection_head; aux != NULL; aux = next)
2438 GNUNET_CONTAINER_DLL_remove (t->connection_head, t->connection_tail, aux);
2443 conns = GCT_count_connections (t);
2445 && GNUNET_SCHEDULER_NO_TASK == t->destroy_task
2446 && CADET_TUNNEL_SHUTDOWN != t->cstate
2447 && GNUNET_NO == shutting_down)
2449 if (0 == GCT_count_any_connections (t))
2450 GCT_change_cstate (t, CADET_TUNNEL_SEARCHING);
2452 GCT_change_cstate (t, CADET_TUNNEL_WAITING);
2455 /* Start new connections if needed */
2456 if (CONNECTIONS_PER_TUNNEL > conns
2457 && GNUNET_SCHEDULER_NO_TASK == t->destroy_task
2458 && CADET_TUNNEL_SHUTDOWN != t->cstate
2459 && GNUNET_NO == shutting_down)
2461 LOG (GNUNET_ERROR_TYPE_DEBUG, " too few connections, getting new ones\n");
2462 GCP_connect (t->peer); /* Will change cstate to WAITING when possible */
2466 /* If not marked as ready, no change is needed */
2467 if (CADET_TUNNEL_READY != t->cstate)
2470 /* Check if any connection is ready to maintain cstate */
2471 for (aux = t->connection_head; aux != NULL; aux = aux->next)
2472 if (CADET_CONNECTION_READY == GCC_get_state (aux->c))
2478 * Add a channel to a tunnel.
2481 * @param ch Channel.
2484 GCT_add_channel (struct CadetTunnel *t, struct CadetChannel *ch)
2486 struct CadetTChannel *aux;
2488 GNUNET_assert (NULL != ch);
2490 LOG (GNUNET_ERROR_TYPE_DEBUG, "Adding channel %p to tunnel %p\n", ch, t);
2492 for (aux = t->channel_head; aux != NULL; aux = aux->next)
2494 LOG (GNUNET_ERROR_TYPE_DEBUG, " already there %p\n", aux->ch);
2499 aux = GNUNET_new (struct CadetTChannel);
2501 LOG (GNUNET_ERROR_TYPE_DEBUG, " adding %p to %p\n", aux, t->channel_head);
2502 GNUNET_CONTAINER_DLL_insert_tail (t->channel_head, t->channel_tail, aux);
2504 if (GNUNET_SCHEDULER_NO_TASK != t->destroy_task)
2506 GNUNET_SCHEDULER_cancel (t->destroy_task);
2507 t->destroy_task = GNUNET_SCHEDULER_NO_TASK;
2508 LOG (GNUNET_ERROR_TYPE_DEBUG, " undo destroy!\n");
2514 * Remove a channel from a tunnel.
2517 * @param ch Channel.
2520 GCT_remove_channel (struct CadetTunnel *t, struct CadetChannel *ch)
2522 struct CadetTChannel *aux;
2524 LOG (GNUNET_ERROR_TYPE_DEBUG, "Removing channel %p from tunnel %p\n", ch, t);
2525 for (aux = t->channel_head; aux != NULL; aux = aux->next)
2529 LOG (GNUNET_ERROR_TYPE_DEBUG, " found! %s\n", GCCH_2s (ch));
2530 GNUNET_CONTAINER_DLL_remove (t->channel_head, t->channel_tail, aux);
2539 * Search for a channel by global ID.
2541 * @param t Tunnel containing the channel.
2542 * @param chid Public channel number.
2544 * @return channel handler, NULL if doesn't exist
2546 struct CadetChannel *
2547 GCT_get_channel (struct CadetTunnel *t, CADET_ChannelNumber chid)
2549 struct CadetTChannel *iter;
2554 for (iter = t->channel_head; NULL != iter; iter = iter->next)
2556 if (GCCH_get_id (iter->ch) == chid)
2560 return NULL == iter ? NULL : iter->ch;
2565 * @brief Destroy a tunnel and free all resources.
2567 * Should only be called a while after the tunnel has been marked as destroyed,
2568 * in case there is a new channel added to the same peer shortly after marking
2569 * the tunnel. This way we avoid a new public key handshake.
2571 * @param cls Closure (tunnel to destroy).
2572 * @param tc Task context.
2575 delayed_destroy (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
2577 struct CadetTunnel *t = cls;
2578 struct CadetTConnection *iter;
2580 LOG (GNUNET_ERROR_TYPE_DEBUG, "delayed destroying tunnel %p\n", t);
2581 if (0 != (GNUNET_SCHEDULER_REASON_SHUTDOWN & tc->reason))
2583 LOG (GNUNET_ERROR_TYPE_WARNING,
2584 "Not destroying tunnel, due to shutdown. "
2585 "Tunnel at %p should have been freed by GCT_shutdown\n", t);
2588 t->destroy_task = GNUNET_SCHEDULER_NO_TASK;
2589 t->cstate = CADET_TUNNEL_SHUTDOWN;
2591 for (iter = t->connection_head; NULL != iter; iter = iter->next)
2593 GCC_send_destroy (iter->c);
2600 * Tunnel is empty: destroy it.
2602 * Notifies all connections about the destruction.
2604 * @param t Tunnel to destroy.
2607 GCT_destroy_empty (struct CadetTunnel *t)
2609 if (GNUNET_YES == shutting_down)
2610 return; /* Will be destroyed immediately anyway */
2612 if (GNUNET_SCHEDULER_NO_TASK != t->destroy_task)
2614 LOG (GNUNET_ERROR_TYPE_WARNING,
2615 "Tunnel %s is already scheduled for destruction. Tunnel debug dump:\n",
2617 GCT_debug (t, GNUNET_ERROR_TYPE_WARNING);
2619 /* should never happen, tunnel can only become empty once, and the
2620 * task identifier should be NO_TASK (cleaned when the tunnel was created
2621 * or became un-empty)
2626 LOG (GNUNET_ERROR_TYPE_DEBUG, "Tunnel %s empty: scheduling destruction\n",
2629 // FIXME make delay a config option
2630 t->destroy_task = GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_MINUTES,
2631 &delayed_destroy, t);
2632 LOG (GNUNET_ERROR_TYPE_DEBUG, "Scheduled destroy of %p as %llu\n",
2633 t, t->destroy_task);
2638 * Destroy tunnel if empty (no more channels).
2640 * @param t Tunnel to destroy if empty.
2643 GCT_destroy_if_empty (struct CadetTunnel *t)
2645 LOG (GNUNET_ERROR_TYPE_DEBUG, "Tunnel %s destroy if empty\n", GCT_2s (t));
2646 if (0 < GCT_count_channels (t))
2649 GCT_destroy_empty (t);
2654 * Destroy the tunnel.
2656 * This function does not generate any warning traffic to clients or peers.
2659 * Cancel messages belonging to this tunnel queued to neighbors.
2660 * Free any allocated resources linked to the tunnel.
2662 * @param t The tunnel to destroy.
2665 GCT_destroy (struct CadetTunnel *t)
2667 struct CadetTConnection *iter_c;
2668 struct CadetTConnection *next_c;
2669 struct CadetTChannel *iter_ch;
2670 struct CadetTChannel *next_ch;
2675 LOG (GNUNET_ERROR_TYPE_DEBUG, "destroying tunnel %s\n", GCP_2s (t->peer));
2677 GNUNET_break (GNUNET_YES ==
2678 GNUNET_CONTAINER_multipeermap_remove (tunnels,
2679 GCP_get_id (t->peer), t));
2681 for (iter_c = t->connection_head; NULL != iter_c; iter_c = next_c)
2683 next_c = iter_c->next;
2684 GCC_destroy (iter_c->c);
2686 for (iter_ch = t->channel_head; NULL != iter_ch; iter_ch = next_ch)
2688 next_ch = iter_ch->next;
2689 GCCH_destroy (iter_ch->ch);
2690 /* Should only happen on shutdown, but it's ok. */
2693 if (GNUNET_SCHEDULER_NO_TASK != t->destroy_task)
2695 LOG (GNUNET_ERROR_TYPE_DEBUG, "cancelling dest: %llX\n", t->destroy_task);
2696 GNUNET_SCHEDULER_cancel (t->destroy_task);
2697 t->destroy_task = GNUNET_SCHEDULER_NO_TASK;
2700 if (GNUNET_SCHEDULER_NO_TASK != t->trim_connections_task)
2702 LOG (GNUNET_ERROR_TYPE_DEBUG, "cancelling trim: %llX\n",
2703 t->trim_connections_task);
2704 GNUNET_SCHEDULER_cancel (t->trim_connections_task);
2705 t->trim_connections_task = GNUNET_SCHEDULER_NO_TASK;
2708 GNUNET_STATISTICS_update (stats, "# tunnels", -1, GNUNET_NO);
2709 GCP_set_tunnel (t->peer, NULL);
2711 if (GNUNET_SCHEDULER_NO_TASK != t->rekey_task)
2713 GNUNET_SCHEDULER_cancel (t->rekey_task);
2714 t->rekey_task = GNUNET_SCHEDULER_NO_TASK;
2716 if (NULL != t->kx_ctx)
2718 if (GNUNET_SCHEDULER_NO_TASK != t->kx_ctx->finish_task)
2719 GNUNET_SCHEDULER_cancel (t->kx_ctx->finish_task);
2720 GNUNET_free (t->kx_ctx);
2727 * @brief Use the given path for the tunnel.
2728 * Update the next and prev hops (and RCs).
2729 * (Re)start the path refresh in case the tunnel is locally owned.
2731 * @param t Tunnel to update.
2732 * @param p Path to use.
2734 * @return Connection created.
2736 struct CadetConnection *
2737 GCT_use_path (struct CadetTunnel *t, struct CadetPeerPath *p)
2739 struct CadetConnection *c;
2740 struct GNUNET_CADET_Hash cid;
2741 unsigned int own_pos;
2743 if (NULL == t || NULL == p)
2749 if (CADET_TUNNEL_SHUTDOWN == t->cstate)
2755 for (own_pos = 0; own_pos < p->length; own_pos++)
2757 if (p->peers[own_pos] == myid)
2760 if (own_pos >= p->length)
2762 GNUNET_break_op (0);
2766 GNUNET_CRYPTO_random_block (GNUNET_CRYPTO_QUALITY_NONCE, &cid, sizeof (cid));
2767 c = GCC_new (&cid, t, p, own_pos);
2770 /* Path was flawed */
2773 GCT_add_connection (t, c);
2779 * Count all created connections of a tunnel. Not necessarily ready connections!
2781 * @param t Tunnel on which to count.
2783 * @return Number of connections created, either being established or ready.
2786 GCT_count_any_connections (struct CadetTunnel *t)
2788 struct CadetTConnection *iter;
2794 for (count = 0, iter = t->connection_head; NULL != iter; iter = iter->next)
2802 * Count established (ready) connections of a tunnel.
2804 * @param t Tunnel on which to count.
2806 * @return Number of connections.
2809 GCT_count_connections (struct CadetTunnel *t)
2811 struct CadetTConnection *iter;
2817 for (count = 0, iter = t->connection_head; NULL != iter; iter = iter->next)
2818 if (CADET_CONNECTION_READY == GCC_get_state (iter->c))
2826 * Count channels of a tunnel.
2828 * @param t Tunnel on which to count.
2830 * @return Number of channels.
2833 GCT_count_channels (struct CadetTunnel *t)
2835 struct CadetTChannel *iter;
2838 for (count = 0, iter = t->channel_head;
2840 iter = iter->next, count++) /* skip */;
2847 * Get the connectivity state of a tunnel.
2851 * @return Tunnel's connectivity state.
2853 enum CadetTunnelCState
2854 GCT_get_cstate (struct CadetTunnel *t)
2859 return (enum CadetTunnelCState) -1;
2866 * Get the encryption state of a tunnel.
2870 * @return Tunnel's encryption state.
2872 enum CadetTunnelEState
2873 GCT_get_estate (struct CadetTunnel *t)
2878 return (enum CadetTunnelEState) -1;
2884 * Get the maximum buffer space for a tunnel towards a local client.
2888 * @return Biggest buffer space offered by any channel in the tunnel.
2891 GCT_get_channels_buffer (struct CadetTunnel *t)
2893 struct CadetTChannel *iter;
2894 unsigned int buffer;
2895 unsigned int ch_buf;
2897 if (NULL == t->channel_head)
2899 /* Probably getting buffer for a channel create/handshake. */
2900 LOG (GNUNET_ERROR_TYPE_DEBUG, " no channels, allow max\n");
2905 for (iter = t->channel_head; NULL != iter; iter = iter->next)
2907 ch_buf = get_channel_buffer (iter);
2908 if (ch_buf > buffer)
2916 * Get the total buffer space for a tunnel for P2P traffic.
2920 * @return Buffer space offered by all connections in the tunnel.
2923 GCT_get_connections_buffer (struct CadetTunnel *t)
2925 struct CadetTConnection *iter;
2926 unsigned int buffer;
2928 if (GNUNET_NO == is_ready (t))
2930 if (count_queued_data (t) > 3)
2937 for (iter = t->connection_head; NULL != iter; iter = iter->next)
2939 if (GCC_get_state (iter->c) != CADET_CONNECTION_READY)
2943 buffer += get_connection_buffer (iter);
2951 * Get the tunnel's destination.
2955 * @return ID of the destination peer.
2957 const struct GNUNET_PeerIdentity *
2958 GCT_get_destination (struct CadetTunnel *t)
2960 return GCP_get_id (t->peer);
2965 * Get the tunnel's next free global channel ID.
2969 * @return GID of a channel free to use.
2972 GCT_get_next_chid (struct CadetTunnel *t)
2974 CADET_ChannelNumber chid;
2975 CADET_ChannelNumber mask;
2978 /* Set bit 30 depending on the ID relationship. Bit 31 is always 0 for GID.
2979 * If our ID is bigger or loopback tunnel, start at 0, bit 30 = 0
2980 * If peer's ID is bigger, start at 0x4... bit 30 = 1
2982 result = GNUNET_CRYPTO_cmp_peer_identity (&my_full_id, GCP_get_id (t->peer));
2987 t->next_chid |= mask;
2989 while (NULL != GCT_get_channel (t, t->next_chid))
2991 LOG (GNUNET_ERROR_TYPE_DEBUG, "Channel %u exists...\n", t->next_chid);
2992 t->next_chid = (t->next_chid + 1) & ~GNUNET_CADET_LOCAL_CHANNEL_ID_CLI;
2993 t->next_chid |= mask;
2995 chid = t->next_chid;
2996 t->next_chid = (t->next_chid + 1) & ~GNUNET_CADET_LOCAL_CHANNEL_ID_CLI;
2997 t->next_chid |= mask;
3004 * Send ACK on one or more channels due to buffer in connections.
3006 * @param t Channel which has some free buffer space.
3009 GCT_unchoke_channels (struct CadetTunnel *t)
3011 struct CadetTChannel *iter;
3012 unsigned int buffer;
3013 unsigned int channels = GCT_count_channels (t);
3014 unsigned int choked_n;
3015 struct CadetChannel *choked[channels];
3017 LOG (GNUNET_ERROR_TYPE_DEBUG, "GCT_unchoke_channels on %s\n", GCT_2s (t));
3018 LOG (GNUNET_ERROR_TYPE_DEBUG, " head: %p\n", t->channel_head);
3019 if (NULL != t->channel_head)
3020 LOG (GNUNET_ERROR_TYPE_DEBUG, " head ch: %p\n", t->channel_head->ch);
3022 /* Get buffer space */
3023 buffer = GCT_get_connections_buffer (t);
3029 /* Count and remember choked channels */
3031 for (iter = t->channel_head; NULL != iter; iter = iter->next)
3033 if (GNUNET_NO == get_channel_allowed (iter))
3035 choked[choked_n++] = iter->ch;
3039 /* Unchoke random channels */
3040 while (0 < buffer && 0 < choked_n)
3042 unsigned int r = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK,
3044 GCCH_allow_client (choked[r], GCCH_is_origin (choked[r], GNUNET_YES));
3047 choked[r] = choked[choked_n];
3053 * Send ACK on one or more connections due to buffer space to the client.
3055 * Iterates all connections of the tunnel and sends ACKs appropriately.
3060 GCT_send_connection_acks (struct CadetTunnel *t)
3062 struct CadetTConnection *iter;
3065 uint32_t allow_per_connection;
3067 unsigned int buffer;
3069 LOG (GNUNET_ERROR_TYPE_DEBUG, "Tunnel send connection ACKs on %s\n",
3078 if (CADET_TUNNEL_READY != t->cstate)
3081 buffer = GCT_get_channels_buffer (t);
3082 LOG (GNUNET_ERROR_TYPE_DEBUG, " buffer %u\n", buffer);
3084 /* Count connections, how many messages are already allowed */
3085 cs = GCT_count_connections (t);
3086 for (allowed = 0, iter = t->connection_head; NULL != iter; iter = iter->next)
3088 allowed += get_connection_allowed (iter);
3090 LOG (GNUNET_ERROR_TYPE_DEBUG, " allowed %u\n", allowed);
3092 /* Make sure there is no overflow */
3093 if (allowed > buffer)
3096 /* Authorize connections to send more data */
3097 to_allow = buffer - allowed;
3099 for (iter = t->connection_head;
3100 NULL != iter && to_allow > 0;
3103 if (CADET_CONNECTION_READY != GCC_get_state (iter->c)
3104 || get_connection_allowed (iter) > 64 / 3)
3108 allow_per_connection = to_allow/cs;
3109 to_allow -= allow_per_connection;
3111 GCC_allow (iter->c, allow_per_connection,
3112 GCC_is_origin (iter->c, GNUNET_NO));
3117 /* Since we don't allow if it's allowed to send 64/3, this can happen. */
3118 LOG (GNUNET_ERROR_TYPE_DEBUG, " reminding to_allow: %u\n", to_allow);
3124 * Cancel a previously sent message while it's in the queue.
3126 * ONLY can be called before the continuation given to the send function
3127 * is called. Once the continuation is called, the message is no longer in the
3130 * @param q Handle to the queue.
3133 GCT_cancel (struct CadetTunnelQueue *q)
3138 /* tun_message_sent() will be called and free q */
3140 else if (NULL != q->tqd)
3142 unqueue_data (q->tqd);
3144 if (NULL != q->cont)
3145 q->cont (q->cont_cls, NULL, q, 0, 0);
3156 * Sends an already built message on a tunnel, encrypting it and
3157 * choosing the best connection if not provided.
3159 * @param message Message to send. Function modifies it.
3160 * @param t Tunnel on which this message is transmitted.
3161 * @param c Connection to use (autoselect if NULL).
3162 * @param force Force the tunnel to take the message (buffer overfill).
3163 * @param cont Continuation to call once message is really sent.
3164 * @param cont_cls Closure for @c cont.
3166 * @return Handle to cancel message. NULL if @c cont is NULL.
3168 struct CadetTunnelQueue *
3169 GCT_send_prebuilt_message (const struct GNUNET_MessageHeader *message,
3170 struct CadetTunnel *t, struct CadetConnection *c,
3171 int force, GCT_sent cont, void *cont_cls)
3173 return send_prebuilt_message (message, t, c, force, cont, cont_cls, NULL);
3177 * Sends an already built and encrypted message on a tunnel, choosing the best
3178 * connection. Useful for re-queueing messages queued on a destroyed connection.
3180 * @param message Message to send. Function modifies it.
3181 * @param t Tunnel on which this message is transmitted.
3184 GCT_resend_message (const struct GNUNET_MessageHeader *message,
3185 struct CadetTunnel *t)
3187 struct CadetConnection *c;
3190 c = tunnel_get_connection (t);
3193 /* TODO queue in tunnel, marked as encrypted */
3194 LOG (GNUNET_ERROR_TYPE_DEBUG, "No connection available, dropping.\n");
3197 fwd = GCC_is_origin (c, GNUNET_YES);
3198 GNUNET_break (NULL == GCC_send_prebuilt_message (message, 0, 0, c, fwd,
3199 GNUNET_YES, NULL, NULL));
3204 * Is the tunnel directed towards the local peer?
3208 * @return #GNUNET_YES if it is loopback.
3211 GCT_is_loopback (const struct CadetTunnel *t)
3213 return (myid == GCP_get_short_id (t->peer));
3218 * Is the tunnel this path already?
3223 * @return #GNUNET_YES a connection uses this path.
3226 GCT_is_path_used (const struct CadetTunnel *t, const struct CadetPeerPath *p)
3228 struct CadetTConnection *iter;
3230 for (iter = t->connection_head; NULL != iter; iter = iter->next)
3231 if (path_equivalent (GCC_get_path (iter->c), p))
3239 * Get a cost of a path for a tunnel considering existing connections.
3242 * @param path Candidate path.
3244 * @return Cost of the path (path length + number of overlapping nodes)
3247 GCT_get_path_cost (const struct CadetTunnel *t,
3248 const struct CadetPeerPath *path)
3250 struct CadetTConnection *iter;
3251 const struct CadetPeerPath *aux;
3252 unsigned int overlap;
3260 GNUNET_assert (NULL != t);
3262 for (i = 0; i < path->length; i++)
3264 for (iter = t->connection_head; NULL != iter; iter = iter->next)
3266 aux = GCC_get_path (iter->c);
3270 for (j = 0; j < aux->length; j++)
3272 if (path->peers[i] == aux->peers[j])
3280 return path->length + overlap;
3285 * Get the static string for the peer this tunnel is directed.
3289 * @return Static string the destination peer's ID.
3292 GCT_2s (const struct CadetTunnel *t)
3297 return GCP_2s (t->peer);
3301 /******************************************************************************/
3302 /***************************** INFO/DEBUG *******************************/
3303 /******************************************************************************/
3306 * Log all possible info about the tunnel state.
3308 * @param t Tunnel to debug.
3309 * @param level Debug level to use.
3312 GCT_debug (const struct CadetTunnel *t, enum GNUNET_ErrorType level)
3314 struct CadetTChannel *iterch;
3315 struct CadetTConnection *iterc;
3318 do_log = GNUNET_get_log_call_status (level & (~GNUNET_ERROR_TYPE_BULK),
3320 __FILE__, __FUNCTION__, __LINE__);
3324 LOG2 (level, "TTT DEBUG TUNNEL TOWARDS %s\n", GCT_2s (t));
3325 LOG2 (level, "TTT cstate %s, estate %s\n",
3326 cstate2s (t->cstate), estate2s (t->estate));
3327 LOG2 (level, "TTT kx_ctx %p, rekey_task %u, finish task %u\n",
3328 t->kx_ctx, t->rekey_task, t->kx_ctx ? t->kx_ctx->finish_task : 0);
3329 #if DUMP_KEYS_TO_STDERR
3330 LOG2 (level, "TTT my EPHM\t %s\n",
3331 GNUNET_h2s ((struct GNUNET_HashCode *) &kx_msg.ephemeral_key));
3332 LOG2 (level, "TTT peers EPHM:\t %s\n",
3333 GNUNET_h2s ((struct GNUNET_HashCode *) &t->peers_ephemeral_key));
3334 LOG2 (level, "TTT ENC key:\t %s\n",
3335 GNUNET_h2s ((struct GNUNET_HashCode *) &t->e_key));
3336 LOG2 (level, "TTT DEC key:\t %s\n",
3337 GNUNET_h2s ((struct GNUNET_HashCode *) &t->d_key));
3340 LOG2 (level, "TTT OLD ENC key:\t %s\n",
3341 GNUNET_h2s ((struct GNUNET_HashCode *) &t->kx_ctx->e_key_old));
3342 LOG2 (level, "TTT OLD DEC key:\t %s\n",
3343 GNUNET_h2s ((struct GNUNET_HashCode *) &t->kx_ctx->d_key_old));
3346 LOG2 (level, "TTT tq_head %p, tq_tail %p\n", t->tq_head, t->tq_tail);
3347 LOG2 (level, "TTT destroy %u\n", t->destroy_task);
3349 LOG2 (level, "TTT channels:\n");
3350 for (iterch = t->channel_head; NULL != iterch; iterch = iterch->next)
3352 LOG2 (level, "TTT - %s\n", GCCH_2s (iterch->ch));
3355 LOG2 (level, "TTT connections:\n");
3356 for (iterc = t->connection_head; NULL != iterc; iterc = iterc->next)
3358 GCC_debug (iterc->c, level);
3361 LOG2 (level, "TTT DEBUG TUNNEL END\n");
3366 * Iterate all tunnels.
3368 * @param iter Iterator.
3369 * @param cls Closure for @c iter.
3372 GCT_iterate_all (GNUNET_CONTAINER_PeerMapIterator iter, void *cls)
3374 GNUNET_CONTAINER_multipeermap_iterate (tunnels, iter, cls);
3379 * Count all tunnels.
3381 * @return Number of tunnels to remote peers kept by this peer.
3384 GCT_count_all (void)
3386 return GNUNET_CONTAINER_multipeermap_size (tunnels);
3391 * Iterate all connections of a tunnel.
3393 * @param t Tunnel whose connections to iterate.
3394 * @param iter Iterator.
3395 * @param cls Closure for @c iter.
3398 GCT_iterate_connections (struct CadetTunnel *t, GCT_conn_iter iter, void *cls)
3400 struct CadetTConnection *ct;
3402 for (ct = t->connection_head; NULL != ct; ct = ct->next)
3408 * Iterate all channels of a tunnel.
3410 * @param t Tunnel whose channels to iterate.
3411 * @param iter Iterator.
3412 * @param cls Closure for @c iter.
3415 GCT_iterate_channels (struct CadetTunnel *t, GCT_chan_iter iter, void *cls)
3417 struct CadetTChannel *cht;
3419 for (cht = t->channel_head; NULL != cht; cht = cht->next)
3420 iter (cls, cht->ch);