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 * Same as @c e_key_old, for the case of two simultaneous KX.
108 * This can happen if cadet decides to start a re-key while the peer has also
109 * started its re-key (due to network delay this is impossible to avoid).
110 * In this case, the key material generated with the peer's old ephemeral
111 * *might* (but doesn't have to) be incorrect.
112 * Since no more than two re-keys can happen simultaneously, this is enough.
114 struct GNUNET_CRYPTO_SymmetricSessionKey e_key_old2;
117 * Same as @c d_key_old, for the case described in @c e_key_old2.
119 struct GNUNET_CRYPTO_SymmetricSessionKey d_key_old2;
122 * Challenge to send and expect in the PONG.
127 * When the rekey started. One minute after this the new key will be used.
129 struct GNUNET_TIME_Absolute rekey_start_time;
132 * Task for delayed destruction of the Key eXchange context, to allow delayed
133 * messages with the old key to be decrypted successfully.
135 struct GNUNET_SCHEDULER_Task * finish_task;
139 * Struct containing all information regarding a tunnel to a peer.
144 * Endpoint of the tunnel.
146 struct CadetPeer *peer;
149 * State of the tunnel connectivity.
151 enum CadetTunnelCState cstate;
154 * State of the tunnel encryption.
156 enum CadetTunnelEState estate;
159 * Key eXchange context.
161 struct CadetTunnelKXCtx *kx_ctx;
164 * Peer's ephemeral key, to recreate @c e_key and @c d_key when own ephemeral
167 struct GNUNET_CRYPTO_EcdhePublicKey peers_ephemeral_key;
170 * Encryption ("our") key. It is only "confirmed" if kx_ctx is NULL.
172 struct GNUNET_CRYPTO_SymmetricSessionKey e_key;
175 * Decryption ("their") key. It is only "confirmed" if kx_ctx is NULL.
177 struct GNUNET_CRYPTO_SymmetricSessionKey d_key;
180 * Task to start the rekey process.
182 struct GNUNET_SCHEDULER_Task * rekey_task;
185 * Paths that are actively used to reach the destination peer.
187 struct CadetTConnection *connection_head;
188 struct CadetTConnection *connection_tail;
191 * Next connection number.
196 * Channels inside this tunnel.
198 struct CadetTChannel *channel_head;
199 struct CadetTChannel *channel_tail;
202 * Channel ID for the next created channel.
204 CADET_ChannelNumber next_chid;
207 * Destroy flag: if true, destroy on last message.
209 struct GNUNET_SCHEDULER_Task * destroy_task;
212 * Queued messages, to transmit once tunnel gets connected.
214 struct CadetTunnelDelayed *tq_head;
215 struct CadetTunnelDelayed *tq_tail;
218 * Task to trim connections if too many are present.
220 struct GNUNET_SCHEDULER_Task * trim_connections_task;
223 * Ephemeral message in the queue (to avoid queueing more than one).
225 struct CadetConnectionQueue *ephm_h;
228 * Pong message in the queue.
230 struct CadetConnectionQueue *pong_h;
235 * Struct used to save messages in a non-ready tunnel to send once connected.
237 struct CadetTunnelDelayed
242 struct CadetTunnelDelayed *next;
243 struct CadetTunnelDelayed *prev;
248 struct CadetTunnel *t;
251 * Tunnel queue given to the channel to cancel request. Update on send_queued.
253 struct CadetTunnelQueue *tq;
258 /* struct GNUNET_MessageHeader *msg; */
263 * Handle for messages queued but not yet sent.
265 struct CadetTunnelQueue
268 * Connection queue handle, to cancel if necessary.
270 struct CadetConnectionQueue *cq;
273 * Handle in case message hasn't been given to a connection yet.
275 struct CadetTunnelDelayed *tqd;
278 * Continuation to call once sent.
283 * Closure for @c cont.
289 /******************************************************************************/
290 /******************************* GLOBALS ***********************************/
291 /******************************************************************************/
294 * Global handle to the statistics service.
296 extern struct GNUNET_STATISTICS_Handle *stats;
299 * Local peer own ID (memory efficient handle).
301 extern GNUNET_PEER_Id myid;
304 * Local peer own ID (full value).
306 extern struct GNUNET_PeerIdentity my_full_id;
310 * Don't try to recover tunnels if shutting down.
312 extern int shutting_down;
316 * Set of all tunnels, in order to trigger a new exchange on rekey.
317 * Indexed by peer's ID.
319 static struct GNUNET_CONTAINER_MultiPeerMap *tunnels;
322 * Default TTL for payload packets.
324 static unsigned long long default_ttl;
329 const static struct GNUNET_CRYPTO_EddsaPrivateKey *my_private_key;
332 * Own ephemeral private key.
334 static struct GNUNET_CRYPTO_EcdhePrivateKey *my_ephemeral_key;
337 * Cached message used to perform a key exchange.
339 static struct GNUNET_CADET_KX_Ephemeral kx_msg;
342 * Task to generate a new ephemeral key.
344 static struct GNUNET_SCHEDULER_Task * rekey_task;
349 static struct GNUNET_TIME_Relative rekey_period;
351 /******************************************************************************/
352 /******************************** STATIC ***********************************/
353 /******************************************************************************/
356 * Get string description for tunnel connectivity state.
358 * @param cs Tunnel state.
360 * @return String representation.
363 cstate2s (enum CadetTunnelCState cs)
369 case CADET_TUNNEL_NEW:
370 return "CADET_TUNNEL_NEW";
371 case CADET_TUNNEL_SEARCHING:
372 return "CADET_TUNNEL_SEARCHING";
373 case CADET_TUNNEL_WAITING:
374 return "CADET_TUNNEL_WAITING";
375 case CADET_TUNNEL_READY:
376 return "CADET_TUNNEL_READY";
377 case CADET_TUNNEL_SHUTDOWN:
378 return "CADET_TUNNEL_SHUTDOWN";
380 SPRINTF (buf, "%u (UNKNOWN STATE)", cs);
388 * Get string description for tunnel encryption state.
390 * @param es Tunnel state.
392 * @return String representation.
395 estate2s (enum CadetTunnelEState es)
401 case CADET_TUNNEL_KEY_UNINITIALIZED:
402 return "CADET_TUNNEL_KEY_UNINITIALIZED";
403 case CADET_TUNNEL_KEY_SENT:
404 return "CADET_TUNNEL_KEY_SENT";
405 case CADET_TUNNEL_KEY_PING:
406 return "CADET_TUNNEL_KEY_PING";
407 case CADET_TUNNEL_KEY_OK:
408 return "CADET_TUNNEL_KEY_OK";
409 case CADET_TUNNEL_KEY_REKEY:
410 return "CADET_TUNNEL_KEY_REKEY";
412 SPRINTF (buf, "%u (UNKNOWN STATE)", es);
420 * @brief Check if tunnel is ready to send traffic.
422 * Tunnel must be connected and with encryption correctly set up.
424 * @param t Tunnel to check.
426 * @return #GNUNET_YES if ready, #GNUNET_NO otherwise
429 is_ready (struct CadetTunnel *t)
433 GCT_debug (t, GNUNET_ERROR_TYPE_DEBUG);
434 ready = CADET_TUNNEL_READY == t->cstate
435 && (CADET_TUNNEL_KEY_OK == t->estate
436 || CADET_TUNNEL_KEY_REKEY == t->estate);
437 ready = ready || GCT_is_loopback (t);
443 * Check if a key is invalid (NULL pointer or all 0)
445 * @param key Key to check.
447 * @return #GNUNET_YES if key is null, #GNUNET_NO if exists and is not 0.
450 is_key_null (struct GNUNET_CRYPTO_SymmetricSessionKey *key)
452 struct GNUNET_CRYPTO_SymmetricSessionKey null_key;
457 memset (&null_key, 0, sizeof (null_key));
458 if (0 == memcmp (key, &null_key, sizeof (null_key)))
465 * Ephemeral key message purpose size.
467 * @return Size of the part of the ephemeral key message that must be signed.
470 ephemeral_purpose_size (void)
472 return sizeof (struct GNUNET_CRYPTO_EccSignaturePurpose) +
473 sizeof (struct GNUNET_TIME_AbsoluteNBO) +
474 sizeof (struct GNUNET_TIME_AbsoluteNBO) +
475 sizeof (struct GNUNET_CRYPTO_EcdhePublicKey) +
476 sizeof (struct GNUNET_PeerIdentity);
481 * Size of the encrypted part of a ping message.
483 * @return Size of the encrypted part of a ping message.
486 ping_encryption_size (void)
488 return sizeof (uint32_t);
493 * Get the channel's buffer. ONLY FOR NON-LOOPBACK CHANNELS!!
495 * @param tch Tunnel's channel handle.
497 * @return Amount of messages the channel can still buffer towards the client.
500 get_channel_buffer (const struct CadetTChannel *tch)
504 /* If channel is incoming, is terminal in the FWD direction and fwd is YES */
505 fwd = GCCH_is_terminal (tch->ch, GNUNET_YES);
507 return GCCH_get_buffer (tch->ch, fwd);
512 * Get the channel's allowance status.
514 * @param tch Tunnel's channel handle.
516 * @return #GNUNET_YES if we allowed the client to send data to us.
519 get_channel_allowed (const struct CadetTChannel *tch)
523 /* If channel is outgoing, is origin in the FWD direction and fwd is YES */
524 fwd = GCCH_is_origin (tch->ch, GNUNET_YES);
526 return GCCH_get_allowed (tch->ch, fwd);
531 * Get the connection's buffer.
533 * @param tc Tunnel's connection handle.
535 * @return Amount of messages the connection can still buffer.
538 get_connection_buffer (const struct CadetTConnection *tc)
542 /* If connection is outgoing, is origin in the FWD direction and fwd is YES */
543 fwd = GCC_is_origin (tc->c, GNUNET_YES);
545 return GCC_get_buffer (tc->c, fwd);
550 * Get the connection's allowance.
552 * @param tc Tunnel's connection handle.
554 * @return Amount of messages we have allowed the next peer to send us.
557 get_connection_allowed (const struct CadetTConnection *tc)
561 /* If connection is outgoing, is origin in the FWD direction and fwd is YES */
562 fwd = GCC_is_origin (tc->c, GNUNET_YES);
564 return GCC_get_allowed (tc->c, fwd);
569 * Check that a ephemeral key message s well formed and correctly signed.
571 * @param t Tunnel on which the message came.
572 * @param msg The ephemeral key message.
574 * @return GNUNET_OK if message is fine, GNUNET_SYSERR otherwise.
577 check_ephemeral (struct CadetTunnel *t,
578 const struct GNUNET_CADET_KX_Ephemeral *msg)
580 /* Check message size */
581 if (ntohs (msg->header.size) != sizeof (struct GNUNET_CADET_KX_Ephemeral))
582 return GNUNET_SYSERR;
584 /* Check signature size */
585 if (ntohl (msg->purpose.size) != ephemeral_purpose_size ())
586 return GNUNET_SYSERR;
589 if (0 != memcmp (&msg->origin_identity,
590 GCP_get_id (t->peer),
591 sizeof (struct GNUNET_PeerIdentity)))
592 return GNUNET_SYSERR;
594 /* Check signature */
596 GNUNET_CRYPTO_eddsa_verify (GNUNET_SIGNATURE_PURPOSE_CADET_KX,
599 &msg->origin_identity.public_key))
600 return GNUNET_SYSERR;
607 * Select the best key to use for encryption (send), based on KX status.
609 * Normally, return the current key. If there is a KX in progress and the old
610 * key is fresh enough, return the old key.
612 * @param t Tunnel to choose the key from.
614 * @return The optimal key to encrypt/hmac outgoing traffic.
616 static const struct GNUNET_CRYPTO_SymmetricSessionKey *
617 select_key (const struct CadetTunnel *t)
619 const struct GNUNET_CRYPTO_SymmetricSessionKey *key;
621 if (NULL != t->kx_ctx
622 && NULL == t->kx_ctx->finish_task)
624 struct GNUNET_TIME_Relative age;
626 age = GNUNET_TIME_absolute_get_duration (t->kx_ctx->rekey_start_time);
627 LOG (GNUNET_ERROR_TYPE_DEBUG,
628 " key exchange in progress, started %s ago\n",
629 GNUNET_STRINGS_relative_time_to_string (age, GNUNET_YES));
630 // FIXME make duration of old keys configurable
631 if (age.rel_value_us < GNUNET_TIME_UNIT_MINUTES.rel_value_us)
633 LOG (GNUNET_ERROR_TYPE_DEBUG, " using old key\n");
634 key = &t->kx_ctx->e_key_old;
638 LOG (GNUNET_ERROR_TYPE_DEBUG, " using new key (old key too old)\n");
644 LOG (GNUNET_ERROR_TYPE_DEBUG, " no KX: using current key\n");
654 * @param plaintext Content to HMAC.
655 * @param size Size of @c plaintext.
656 * @param iv Initialization vector for the message.
657 * @param key Key to use.
658 * @param hmac[out] Destination to store the HMAC.
661 t_hmac (const void *plaintext, size_t size,
662 uint32_t iv, const struct GNUNET_CRYPTO_SymmetricSessionKey *key,
663 struct GNUNET_CADET_Hash *hmac)
665 static const char ctx[] = "cadet authentication key";
666 struct GNUNET_CRYPTO_AuthKey auth_key;
667 struct GNUNET_HashCode hash;
669 #if DUMP_KEYS_TO_STDERR
670 LOG (GNUNET_ERROR_TYPE_INFO, " HMAC with key %s\n",
671 GNUNET_h2s ((struct GNUNET_HashCode *) key));
673 GNUNET_CRYPTO_hmac_derive_key (&auth_key, key,
678 /* Two step: CADET_Hash is only 256 bits, HashCode is 512. */
679 GNUNET_CRYPTO_hmac (&auth_key, plaintext, size, &hash);
680 memcpy (hmac, &hash, sizeof (*hmac));
685 * Encrypt daforce_newest_keyta with the tunnel key.
687 * @param t Tunnel whose key to use.
688 * @param dst Destination for the encrypted data.
689 * @param src Source of the plaintext. Can overlap with @c dst.
690 * @param size Size of the plaintext.
691 * @param iv Initialization Vector to use.
692 * @param force_newest_key Force the use of the newest key, otherwise
693 * CADET will use the old key when allowed.
694 * This can happen in the case when a KX is going on
695 * and the old one hasn't expired.
698 t_encrypt (struct CadetTunnel *t, void *dst, const void *src,
699 size_t size, uint32_t iv, int force_newest_key)
701 struct GNUNET_CRYPTO_SymmetricInitializationVector siv;
702 const struct GNUNET_CRYPTO_SymmetricSessionKey *key;
705 LOG (GNUNET_ERROR_TYPE_DEBUG, " t_encrypt start\n");
707 key = GNUNET_YES == force_newest_key ? &t->e_key : select_key (t);
708 #if DUMP_KEYS_TO_STDERR
709 LOG (GNUNET_ERROR_TYPE_INFO, " ENC with key %s\n",
710 GNUNET_h2s ((struct GNUNET_HashCode *) key));
712 GNUNET_CRYPTO_symmetric_derive_iv (&siv, key, &iv, sizeof (iv), NULL);
713 LOG (GNUNET_ERROR_TYPE_DEBUG, " t_encrypt IV derived\n");
714 out_size = GNUNET_CRYPTO_symmetric_encrypt (src, size, key, &siv, dst);
715 LOG (GNUNET_ERROR_TYPE_DEBUG, " t_encrypt end\n");
722 * Decrypt and verify data with the appropriate tunnel key.
724 * @param key Key to use.
725 * @param dst Destination for the plaintext.
726 * @param src Source of the encrypted data. Can overlap with @c dst.
727 * @param size Size of the encrypted data.
728 * @param iv Initialization Vector to use.
730 * @return Size of the decrypted data, -1 if an error was encountered.
733 decrypt (const struct GNUNET_CRYPTO_SymmetricSessionKey *key,
734 void *dst, const void *src, size_t size, uint32_t iv)
736 struct GNUNET_CRYPTO_SymmetricInitializationVector siv;
739 LOG (GNUNET_ERROR_TYPE_DEBUG, " decrypt start\n");
740 LOG (GNUNET_ERROR_TYPE_DEBUG, " decrypt iv\n");
741 GNUNET_CRYPTO_symmetric_derive_iv (&siv, key, &iv, sizeof (iv), NULL);
742 LOG (GNUNET_ERROR_TYPE_DEBUG, " decrypt iv done\n");
743 out_size = GNUNET_CRYPTO_symmetric_decrypt (src, size, key, &siv, dst);
744 LOG (GNUNET_ERROR_TYPE_DEBUG, " decrypt end\n");
751 * Decrypt and verify data with the most recent tunnel key.
753 * @param t Tunnel whose key to use.
754 * @param dst Destination for the plaintext.
755 * @param src Source of the encrypted data. Can overlap with @c dst.
756 * @param size Size of the encrypted data.
757 * @param iv Initialization Vector to use.
759 * @return Size of the decrypted data, -1 if an error was encountered.
762 t_decrypt (struct CadetTunnel *t, void *dst, const void *src,
763 size_t size, uint32_t iv)
767 #if DUMP_KEYS_TO_STDERR
768 LOG (GNUNET_ERROR_TYPE_DEBUG, " t_decrypt with %s\n",
769 GNUNET_h2s ((struct GNUNET_HashCode *) &t->d_key));
771 if (CADET_TUNNEL_KEY_UNINITIALIZED == t->estate)
773 GNUNET_STATISTICS_update (stats, "# non decryptable data", 1, GNUNET_NO);
774 LOG (GNUNET_ERROR_TYPE_WARNING,
775 "got data on %s without a valid key\n",
777 GCT_debug (t, GNUNET_ERROR_TYPE_WARNING);
781 out_size = decrypt (&t->d_key, dst, src, size, iv);
788 * Decrypt and verify data with the appropriate tunnel key and verify that the
789 * data has not been altered since it was sent by the remote peer.
791 * @param t Tunnel whose key to use.
792 * @param dst Destination for the plaintext.
793 * @param src Source of the encrypted data. Can overlap with @c dst.
794 * @param size Size of the encrypted data.
795 * @param iv Initialization Vector to use.
796 * @param msg_hmac HMAC of the message, cannot be NULL.
798 * @return Size of the decrypted data, -1 if an error was encountered.
801 t_decrypt_and_validate (struct CadetTunnel *t,
802 void *dst, const void *src,
803 size_t size, uint32_t iv,
804 const struct GNUNET_CADET_Hash *msg_hmac)
806 struct GNUNET_CRYPTO_SymmetricSessionKey *key;
807 struct GNUNET_CADET_Hash hmac;
810 /* Try primary (newest) key */
812 decrypted_size = decrypt (key, dst, src, size, iv);
813 t_hmac (src, size, iv, key, &hmac);
814 if (0 == memcmp (msg_hmac, &hmac, sizeof (hmac)))
815 return decrypted_size;
817 /* If no key exchange is going on, we just failed. */
818 if (NULL == t->kx_ctx)
820 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
821 "Failed checksum validation on tunnel %s with no KX\n",
823 GNUNET_STATISTICS_update (stats, "# wrong HMAC no KX", 1, GNUNET_NO);
827 /* Try secondary key, from previous KX period. */
828 key = &t->kx_ctx->d_key_old;
829 decrypted_size = decrypt (key, dst, src, size, iv);
830 t_hmac (src, size, iv, key, &hmac);
831 if (0 == memcmp (msg_hmac, &hmac, sizeof (hmac)))
832 return decrypted_size;
834 /* Hail Mary, try tertiary, key, in case of parallel re-keys. */
835 key = &t->kx_ctx->d_key_old2;
836 decrypted_size = decrypt (key, dst, src, size, iv);
837 t_hmac (src, size, iv, key, &hmac);
838 if (0 == memcmp (msg_hmac, &hmac, sizeof (hmac)))
839 return decrypted_size;
841 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
842 "Failed checksum validation on tunnel %s with KX\n",
844 GNUNET_STATISTICS_update (stats, "# wrong HMAC with KX", 1, GNUNET_NO);
850 * Create key material by doing ECDH on the local and remote ephemeral keys.
852 * @param key_material Where to store the key material.
853 * @param ephemeral_key Peer's public ephemeral key.
856 derive_key_material (struct GNUNET_HashCode *key_material,
857 const struct GNUNET_CRYPTO_EcdhePublicKey *ephemeral_key)
860 GNUNET_CRYPTO_ecc_ecdh (my_ephemeral_key,
870 * Create a symmetic key from the identities of both ends and the key material
873 * @param key Destination for the generated key.
874 * @param sender ID of the peer that will encrypt with @c key.
875 * @param receiver ID of the peer that will decrypt with @c key.
876 * @param key_material Hash created with ECDH with the ephemeral keys.
879 derive_symmertic (struct GNUNET_CRYPTO_SymmetricSessionKey *key,
880 const struct GNUNET_PeerIdentity *sender,
881 const struct GNUNET_PeerIdentity *receiver,
882 const struct GNUNET_HashCode *key_material)
884 const char salt[] = "CADET kx salt";
886 GNUNET_CRYPTO_kdf (key, sizeof (struct GNUNET_CRYPTO_SymmetricSessionKey),
888 key_material, sizeof (struct GNUNET_HashCode),
889 sender, sizeof (struct GNUNET_PeerIdentity),
890 receiver, sizeof (struct GNUNET_PeerIdentity),
896 * Derive the tunnel's keys using our own and the peer's ephemeral keys.
898 * @param t Tunnel for which to create the keys.
901 create_keys (struct CadetTunnel *t)
903 struct GNUNET_HashCode km;
905 derive_key_material (&km, &t->peers_ephemeral_key);
906 derive_symmertic (&t->e_key, &my_full_id, GCP_get_id (t->peer), &km);
907 derive_symmertic (&t->d_key, GCP_get_id (t->peer), &my_full_id, &km);
908 #if DUMP_KEYS_TO_STDERR
909 LOG (GNUNET_ERROR_TYPE_INFO, "ME: %s\n",
910 GNUNET_h2s ((struct GNUNET_HashCode *) &kx_msg.ephemeral_key));
911 LOG (GNUNET_ERROR_TYPE_INFO, "PE: %s\n",
912 GNUNET_h2s ((struct GNUNET_HashCode *) &t->peers_ephemeral_key));
913 LOG (GNUNET_ERROR_TYPE_INFO, "KM: %s\n", GNUNET_h2s (&km));
914 LOG (GNUNET_ERROR_TYPE_INFO, "EK: %s\n",
915 GNUNET_h2s ((struct GNUNET_HashCode *) &t->e_key));
916 LOG (GNUNET_ERROR_TYPE_INFO, "DK: %s\n",
917 GNUNET_h2s ((struct GNUNET_HashCode *) &t->d_key));
923 * Create a new Key eXchange context for the tunnel.
925 * If the old keys were verified, keep them for old traffic. Create a new KX
926 * timestamp and a new nonce.
928 * @param t Tunnel for which to create the KX ctx.
931 create_kx_ctx (struct CadetTunnel *t)
933 LOG (GNUNET_ERROR_TYPE_INFO, " new kx ctx for %s\n", GCT_2s (t));
935 if (NULL != t->kx_ctx)
937 if (NULL != t->kx_ctx->finish_task)
939 LOG (GNUNET_ERROR_TYPE_INFO, " resetting exisiting finish task\n");
940 GNUNET_SCHEDULER_cancel (t->kx_ctx->finish_task);
941 t->kx_ctx->finish_task = NULL;
946 t->kx_ctx = GNUNET_new (struct CadetTunnelKXCtx);
947 t->kx_ctx->challenge = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_NONCE,
951 if (CADET_TUNNEL_KEY_OK == t->estate)
953 LOG (GNUNET_ERROR_TYPE_INFO, " backing up keys\n");
954 t->kx_ctx->d_key_old = t->d_key;
955 t->kx_ctx->e_key_old = t->e_key;
958 LOG (GNUNET_ERROR_TYPE_INFO, " old keys not valid, not saving\n");
959 t->kx_ctx->rekey_start_time = GNUNET_TIME_absolute_get ();
965 * @brief Finish the Key eXchange and destroy the old keys.
967 * @param cls Closure (Tunnel for which to finish the KX).
968 * @param tc Task context.
971 finish_kx (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
973 struct CadetTunnel *t = cls;
975 LOG (GNUNET_ERROR_TYPE_INFO, "finish KX for %s\n", GCT_2s (t));
977 if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
979 LOG (GNUNET_ERROR_TYPE_INFO, " shutdown\n");
983 GNUNET_free (t->kx_ctx);
989 * Destroy a Key eXchange context for the tunnel. This function only schedules
990 * the destruction, the freeing of the memory (and clearing of old key material)
991 * happens after a delay!
993 * @param t Tunnel whose KX ctx to destroy.
996 destroy_kx_ctx (struct CadetTunnel *t)
998 struct GNUNET_TIME_Relative delay;
1000 if (NULL == t->kx_ctx || NULL != t->kx_ctx->finish_task)
1003 if (is_key_null (&t->kx_ctx->e_key_old))
1005 t->kx_ctx->finish_task = GNUNET_SCHEDULER_add_now (finish_kx, t);
1009 delay = GNUNET_TIME_relative_divide (rekey_period, 4);
1010 delay = GNUNET_TIME_relative_min (delay, GNUNET_TIME_UNIT_MINUTES);
1012 t->kx_ctx->finish_task = GNUNET_SCHEDULER_add_delayed (delay, finish_kx, t);
1018 * Pick a connection on which send the next data message.
1020 * @param t Tunnel on which to send the message.
1022 * @return The connection on which to send the next message.
1024 static struct CadetConnection *
1025 tunnel_get_connection (struct CadetTunnel *t)
1027 struct CadetTConnection *iter;
1028 struct CadetConnection *best;
1030 unsigned int lowest_q;
1032 LOG (GNUNET_ERROR_TYPE_DEBUG, "tunnel_get_connection %s\n", GCT_2s (t));
1034 lowest_q = UINT_MAX;
1035 for (iter = t->connection_head; NULL != iter; iter = iter->next)
1037 LOG (GNUNET_ERROR_TYPE_DEBUG, " connection %s: %u\n",
1038 GCC_2s (iter->c), GCC_get_state (iter->c));
1039 if (CADET_CONNECTION_READY == GCC_get_state (iter->c))
1041 qn = GCC_get_qn (iter->c, GCC_is_origin (iter->c, GNUNET_YES));
1042 LOG (GNUNET_ERROR_TYPE_DEBUG, " q_n %u, \n", qn);
1050 LOG (GNUNET_ERROR_TYPE_DEBUG, " selected: connection %s\n", GCC_2s (best));
1056 * Callback called when a queued message is sent.
1058 * Calculates the average time and connection packet tracking.
1060 * @param cls Closure (TunnelQueue handle).
1061 * @param c Connection this message was on.
1062 * @param q Connection queue handle (unused).
1063 * @param type Type of message sent.
1064 * @param fwd Was this a FWD going message?
1065 * @param size Size of the message.
1068 tun_message_sent (void *cls,
1069 struct CadetConnection *c,
1070 struct CadetConnectionQueue *q,
1071 uint16_t type, int fwd, size_t size)
1073 struct CadetTunnelQueue *qt = cls;
1074 struct CadetTunnel *t;
1076 LOG (GNUNET_ERROR_TYPE_DEBUG, "tun_message_sent\n");
1078 GNUNET_assert (NULL != qt->cont);
1079 t = NULL == c ? NULL : GCC_get_tunnel (c);
1080 qt->cont (qt->cont_cls, t, qt, type, size);
1086 count_queued_data (const struct CadetTunnel *t)
1088 struct CadetTunnelDelayed *iter;
1091 for (count = 0, iter = t->tq_head; iter != NULL; iter = iter->next)
1098 * Delete a queued message: either was sent or the channel was destroyed
1099 * before the tunnel's key exchange had a chance to finish.
1101 * @param tqd Delayed queue handle.
1104 unqueue_data (struct CadetTunnelDelayed *tqd)
1106 GNUNET_CONTAINER_DLL_remove (tqd->t->tq_head, tqd->t->tq_tail, tqd);
1112 * Cache a message to be sent once tunnel is online.
1114 * @param t Tunnel to hold the message.
1115 * @param msg Message itself (copy will be made).
1117 static struct CadetTunnelDelayed *
1118 queue_data (struct CadetTunnel *t, const struct GNUNET_MessageHeader *msg)
1120 struct CadetTunnelDelayed *tqd;
1121 uint16_t size = ntohs (msg->size);
1123 LOG (GNUNET_ERROR_TYPE_DEBUG, "queue data on Tunnel %s\n", GCT_2s (t));
1125 if (GNUNET_YES == is_ready (t))
1131 tqd = GNUNET_malloc (sizeof (struct CadetTunnelDelayed) + size);
1134 memcpy (&tqd[1], msg, size);
1135 GNUNET_CONTAINER_DLL_insert_tail (t->tq_head, t->tq_tail, tqd);
1141 * Sends an already built message on a tunnel, encrypting it and
1142 * choosing the best connection.
1144 * @param message Message to send. Function modifies it.
1145 * @param t Tunnel on which this message is transmitted.
1146 * @param c Connection to use (autoselect if NULL).
1147 * @param force Force the tunnel to take the message (buffer overfill).
1148 * @param cont Continuation to call once message is really sent.
1149 * @param cont_cls Closure for @c cont.
1150 * @param existing_q In case this a transmission of previously queued data,
1151 * this should be TunnelQueue given to the client.
1154 * @return Handle to cancel message.
1155 * NULL if @c cont is NULL or an error happens and message is dropped.
1157 static struct CadetTunnelQueue *
1158 send_prebuilt_message (const struct GNUNET_MessageHeader *message,
1159 struct CadetTunnel *t, struct CadetConnection *c,
1160 int force, GCT_sent cont, void *cont_cls,
1161 struct CadetTunnelQueue *existing_q)
1163 struct CadetTunnelQueue *tq;
1164 struct GNUNET_CADET_Encrypted *msg;
1165 size_t size = ntohs (message->size);
1166 char cbuf[sizeof (struct GNUNET_CADET_Encrypted) + size];
1172 LOG (GNUNET_ERROR_TYPE_DEBUG, "GMT Send on Tunnel %s\n", GCT_2s (t));
1174 if (GNUNET_NO == is_ready (t))
1176 struct CadetTunnelDelayed *tqd;
1177 /* A non null existing_q indicates sending of queued data.
1178 * Should only happen after tunnel becomes ready.
1180 GNUNET_assert (NULL == existing_q);
1181 tqd = queue_data (t, message);
1184 tq = GNUNET_new (struct CadetTunnelQueue);
1188 tq->cont_cls = cont_cls;
1192 GNUNET_assert (GNUNET_NO == GCT_is_loopback (t));
1194 iv = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_NONCE, UINT32_MAX);
1195 msg = (struct GNUNET_CADET_Encrypted *) cbuf;
1196 msg->header.type = htons (GNUNET_MESSAGE_TYPE_CADET_ENCRYPTED);
1198 GNUNET_assert (t_encrypt (t, &msg[1], message, size, iv, GNUNET_NO) == size);
1199 t_hmac (&msg[1], size, iv, select_key (t), &msg->hmac);
1200 msg->header.size = htons (sizeof (struct GNUNET_CADET_Encrypted) + size);
1203 c = tunnel_get_connection (t);
1206 /* Why is tunnel 'ready'? Should have been queued! */
1207 if (NULL != t->destroy_task)
1210 GCT_debug (t, GNUNET_ERROR_TYPE_WARNING);
1212 return NULL; /* Drop... */
1216 type = ntohs (message->type);
1219 case GNUNET_MESSAGE_TYPE_CADET_DATA:
1220 case GNUNET_MESSAGE_TYPE_CADET_DATA_ACK:
1221 if (GNUNET_MESSAGE_TYPE_CADET_DATA == type)
1222 mid = ntohl (((struct GNUNET_CADET_Data *) message)->mid);
1224 mid = ntohl (((struct GNUNET_CADET_DataACK *) message)->mid);
1226 case GNUNET_MESSAGE_TYPE_CADET_KEEPALIVE:
1227 case GNUNET_MESSAGE_TYPE_CADET_CHANNEL_CREATE:
1228 case GNUNET_MESSAGE_TYPE_CADET_CHANNEL_DESTROY:
1229 case GNUNET_MESSAGE_TYPE_CADET_CHANNEL_ACK:
1230 case GNUNET_MESSAGE_TYPE_CADET_CHANNEL_NACK:
1231 msg->cid = *GCC_get_id (c);
1232 msg->ttl = htonl (default_ttl);
1236 LOG (GNUNET_ERROR_TYPE_ERROR, "type %s not valid\n", GC_m2s (type));
1238 LOG (GNUNET_ERROR_TYPE_DEBUG, "type %s\n", GC_m2s (type));
1240 fwd = GCC_is_origin (c, GNUNET_YES);
1244 GNUNET_break (NULL == GCC_send_prebuilt_message (&msg->header, type, mid, c,
1245 fwd, force, NULL, NULL));
1248 if (NULL == existing_q)
1250 tq = GNUNET_new (struct CadetTunnelQueue); /* FIXME valgrind: leak*/
1257 tq->cq = GCC_send_prebuilt_message (&msg->header, type, mid, c, fwd, force,
1258 &tun_message_sent, tq);
1259 GNUNET_assert (NULL != tq->cq);
1261 tq->cont_cls = cont_cls;
1268 * Send all cached messages that we can, tunnel is online.
1270 * @param t Tunnel that holds the messages. Cannot be loopback.
1273 send_queued_data (struct CadetTunnel *t)
1275 struct CadetTunnelDelayed *tqd;
1276 struct CadetTunnelDelayed *next;
1279 LOG (GNUNET_ERROR_TYPE_INFO, "Send queued data, tunnel %s\n", GCT_2s (t));
1281 if (GCT_is_loopback (t))
1287 if (GNUNET_NO == is_ready (t))
1289 LOG (GNUNET_ERROR_TYPE_DEBUG, " not ready yet: %s/%s\n",
1290 estate2s (t->estate), cstate2s (t->cstate));
1294 room = GCT_get_connections_buffer (t);
1295 LOG (GNUNET_ERROR_TYPE_DEBUG, " buffer space: %u\n", room);
1296 LOG (GNUNET_ERROR_TYPE_DEBUG, " tq head: %p\n", t->tq_head);
1297 for (tqd = t->tq_head; NULL != tqd && room > 0; tqd = next)
1299 LOG (GNUNET_ERROR_TYPE_DEBUG, " sending queued data\n");
1302 send_prebuilt_message ((struct GNUNET_MessageHeader *) &tqd[1],
1303 tqd->t, NULL, GNUNET_YES,
1304 NULL != tqd->tq ? tqd->tq->cont : NULL,
1305 NULL != tqd->tq ? tqd->tq->cont_cls : NULL,
1309 LOG (GNUNET_ERROR_TYPE_DEBUG, "GCT_send_queued_data end\n", GCP_2s (t->peer));
1314 * Callback called when a queued message is sent.
1316 * @param cls Closure.
1317 * @param c Connection this message was on.
1318 * @param type Type of message sent.
1319 * @param fwd Was this a FWD going message?
1320 * @param size Size of the message.
1323 ephm_sent (void *cls,
1324 struct CadetConnection *c,
1325 struct CadetConnectionQueue *q,
1326 uint16_t type, int fwd, size_t size)
1328 struct CadetTunnel *t = cls;
1329 LOG (GNUNET_ERROR_TYPE_DEBUG, "ephm_sent %s\n", GC_m2s (type));
1334 * Callback called when a queued message is sent.
1336 * @param cls Closure.
1337 * @param c Connection this message was on.
1338 * @param type Type of message sent.
1339 * @param fwd Was this a FWD going message?
1340 * @param size Size of the message.
1343 pong_sent (void *cls,
1344 struct CadetConnection *c,
1345 struct CadetConnectionQueue *q,
1346 uint16_t type, int fwd, size_t size)
1348 struct CadetTunnel *t = cls;
1349 LOG (GNUNET_ERROR_TYPE_DEBUG, "pong_sent %s\n", GC_m2s (type));
1355 * Sends key exchange message on a tunnel, choosing the best connection.
1356 * Should not be called on loopback tunnels.
1358 * @param t Tunnel on which this message is transmitted.
1359 * @param message Message to send. Function modifies it.
1361 * @return Handle to the message in the connection queue.
1363 static struct CadetConnectionQueue *
1364 send_kx (struct CadetTunnel *t,
1365 const struct GNUNET_MessageHeader *message)
1367 struct CadetConnection *c;
1368 struct GNUNET_CADET_KX *msg;
1369 size_t size = ntohs (message->size);
1370 char cbuf[sizeof (struct GNUNET_CADET_KX) + size];
1375 LOG (GNUNET_ERROR_TYPE_DEBUG, "GMT KX on Tunnel %s\n", GCT_2s (t));
1377 /* Avoid loopback. */
1378 if (GCT_is_loopback (t))
1380 LOG (GNUNET_ERROR_TYPE_DEBUG, " loopback!\n");
1384 type = ntohs (message->type);
1386 /* Even if tunnel is being destroyed, send anyway.
1387 * Could be a response to a rekey initiated by remote peer,
1388 * who is trying to create a new channel!
1391 /* Must have a connection, or be looking for one. */
1392 if (NULL == t->connection_head)
1394 if (CADET_TUNNEL_SEARCHING != t->cstate)
1396 LOG (GNUNET_ERROR_TYPE_ERROR, "\n\n\n");
1398 LOG (GNUNET_ERROR_TYPE_ERROR, "no connection, sending %s\n", GC_m2s (type));
1399 GCT_debug (t, GNUNET_ERROR_TYPE_ERROR);
1400 GCP_debug (t->peer, GNUNET_ERROR_TYPE_ERROR);
1401 LOG (GNUNET_ERROR_TYPE_ERROR, "\n\n\n");
1406 msg = (struct GNUNET_CADET_KX *) cbuf;
1407 msg->header.type = htons (GNUNET_MESSAGE_TYPE_CADET_KX);
1408 msg->header.size = htons (sizeof (struct GNUNET_CADET_KX) + size);
1409 c = tunnel_get_connection (t);
1412 if (NULL == t->destroy_task
1413 && CADET_TUNNEL_READY == t->cstate)
1416 GCT_debug (t, GNUNET_ERROR_TYPE_ERROR);
1422 case GNUNET_MESSAGE_TYPE_CADET_KX_EPHEMERAL:
1423 GNUNET_assert (NULL == t->ephm_h);
1425 memcpy (&msg[1], message, size);
1427 case GNUNET_MESSAGE_TYPE_CADET_KX_PONG:
1428 GNUNET_assert (NULL == t->pong_h);
1430 memcpy (&msg[1], message, size);
1434 LOG (GNUNET_ERROR_TYPE_DEBUG, "unkown type %s\n", GC_m2s (type));
1438 fwd = GCC_is_origin (t->connection_head->c, GNUNET_YES);
1440 return GCC_send_prebuilt_message (&msg->header, type, 0, c,
1447 * Send the ephemeral key on a tunnel.
1449 * @param t Tunnel on which to send the key.
1452 send_ephemeral (struct CadetTunnel *t)
1454 LOG (GNUNET_ERROR_TYPE_INFO, "===> EPHM for %s\n", GCT_2s (t));
1455 if (NULL != t->ephm_h)
1457 LOG (GNUNET_ERROR_TYPE_INFO, " already queued\n");
1461 kx_msg.sender_status = htonl (t->estate);
1462 kx_msg.iv = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_NONCE, UINT32_MAX);
1463 kx_msg.nonce = t->kx_ctx->challenge;
1464 LOG (GNUNET_ERROR_TYPE_DEBUG, " send nonce c %u\n", kx_msg.nonce);
1465 t_encrypt (t, &kx_msg.nonce, &kx_msg.nonce,
1466 ping_encryption_size(), kx_msg.iv, GNUNET_YES);
1467 LOG (GNUNET_ERROR_TYPE_DEBUG, " send nonce e %u\n", kx_msg.nonce);
1468 t->ephm_h = send_kx (t, &kx_msg.header);
1473 * Send a pong message on a tunnel.
1475 * @param t Tunnel on which to send the pong.
1476 * @param challenge Value sent in the ping that we have to send back.
1479 send_pong (struct CadetTunnel *t, uint32_t challenge)
1481 struct GNUNET_CADET_KX_Pong msg;
1483 LOG (GNUNET_ERROR_TYPE_INFO, "===> PONG for %s\n", GCT_2s (t));
1484 if (NULL != t->pong_h)
1486 LOG (GNUNET_ERROR_TYPE_INFO, " already queued\n");
1489 msg.header.size = htons (sizeof (msg));
1490 msg.header.type = htons (GNUNET_MESSAGE_TYPE_CADET_KX_PONG);
1491 msg.iv = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_NONCE, UINT32_MAX);
1492 msg.nonce = challenge;
1493 LOG (GNUNET_ERROR_TYPE_DEBUG, " sending %u\n", msg.nonce);
1494 t_encrypt (t, &msg.nonce, &msg.nonce,
1495 sizeof (msg.nonce), msg.iv, GNUNET_YES);
1496 LOG (GNUNET_ERROR_TYPE_DEBUG, " e sending %u\n", msg.nonce);
1498 t->pong_h = send_kx (t, &msg.header);
1503 * Initiate a rekey with the remote peer.
1505 * @param cls Closure (tunnel).
1506 * @param tc TaskContext.
1509 rekey_tunnel (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
1511 struct CadetTunnel *t = cls;
1513 t->rekey_task = NULL;
1515 LOG (GNUNET_ERROR_TYPE_INFO, "Re-key Tunnel %s\n", GCT_2s (t));
1516 if (NULL != tc && 0 != (GNUNET_SCHEDULER_REASON_SHUTDOWN & tc->reason))
1519 GNUNET_assert (NULL != t->kx_ctx);
1520 struct GNUNET_TIME_Relative duration;
1522 duration = GNUNET_TIME_absolute_get_duration (t->kx_ctx->rekey_start_time);
1523 LOG (GNUNET_ERROR_TYPE_DEBUG, " kx started %s ago\n",
1524 GNUNET_STRINGS_relative_time_to_string (duration, GNUNET_YES));
1526 // FIXME make duration of old keys configurable
1527 if (duration.rel_value_us >= GNUNET_TIME_UNIT_MINUTES.rel_value_us)
1529 LOG (GNUNET_ERROR_TYPE_DEBUG, " deleting old keys\n");
1530 memset (&t->kx_ctx->d_key_old, 0, sizeof (t->kx_ctx->d_key_old));
1531 memset (&t->kx_ctx->e_key_old, 0, sizeof (t->kx_ctx->e_key_old));
1538 case CADET_TUNNEL_KEY_UNINITIALIZED:
1539 GCT_change_estate (t, CADET_TUNNEL_KEY_SENT);
1542 case CADET_TUNNEL_KEY_SENT:
1545 case CADET_TUNNEL_KEY_OK:
1547 * - state should have changed during rekey_iterator
1548 * - task should have been canceled at pong_handle
1551 GCT_change_estate (t, CADET_TUNNEL_KEY_REKEY);
1554 case CADET_TUNNEL_KEY_PING:
1555 case CADET_TUNNEL_KEY_REKEY:
1559 LOG (GNUNET_ERROR_TYPE_DEBUG, "Unexpected state %u\n", t->estate);
1562 // FIXME exponential backoff
1563 struct GNUNET_TIME_Relative delay;
1565 delay = GNUNET_TIME_relative_divide (rekey_period, 16);
1566 delay = GNUNET_TIME_relative_min (delay, REKEY_WAIT);
1567 LOG (GNUNET_ERROR_TYPE_DEBUG, " next call in %s\n",
1568 GNUNET_STRINGS_relative_time_to_string (delay, GNUNET_YES));
1569 t->rekey_task = GNUNET_SCHEDULER_add_delayed (delay, &rekey_tunnel, t);
1574 * Our ephemeral key has changed, create new session key on all tunnels.
1576 * Each tunnel will start the Key Exchange with a random delay between
1577 * 0 and number_of_tunnels*100 milliseconds, so there are 10 key exchanges
1578 * per second, on average.
1580 * @param cls Closure (size of the hashmap).
1581 * @param key Current public key.
1582 * @param value Value in the hash map (tunnel).
1584 * @return #GNUNET_YES, so we should continue to iterate,
1587 rekey_iterator (void *cls,
1588 const struct GNUNET_PeerIdentity *key,
1591 struct CadetTunnel *t = value;
1592 struct GNUNET_TIME_Relative delay;
1593 long n = (long) cls;
1596 if (NULL != t->rekey_task)
1599 if (GNUNET_YES == GCT_is_loopback (t))
1602 r = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK, (uint32_t) n * 100);
1603 delay = GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MILLISECONDS, r);
1604 t->rekey_task = GNUNET_SCHEDULER_add_delayed (delay, &rekey_tunnel, t);
1606 GCT_change_estate (t, CADET_TUNNEL_KEY_REKEY);
1613 * Create a new ephemeral key and key message, schedule next rekeying.
1615 * @param cls Closure (unused).
1616 * @param tc TaskContext.
1619 rekey (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
1621 struct GNUNET_TIME_Absolute time;
1626 if (0 != (GNUNET_SCHEDULER_REASON_SHUTDOWN & tc->reason))
1629 GNUNET_free_non_null (my_ephemeral_key);
1630 my_ephemeral_key = GNUNET_CRYPTO_ecdhe_key_create ();
1632 time = GNUNET_TIME_absolute_get ();
1633 kx_msg.creation_time = GNUNET_TIME_absolute_hton (time);
1634 time = GNUNET_TIME_absolute_add (time, rekey_period);
1635 time = GNUNET_TIME_absolute_add (time, GNUNET_TIME_UNIT_MINUTES);
1636 kx_msg.expiration_time = GNUNET_TIME_absolute_hton (time);
1637 GNUNET_CRYPTO_ecdhe_key_get_public (my_ephemeral_key, &kx_msg.ephemeral_key);
1638 LOG (GNUNET_ERROR_TYPE_INFO, "GLOBAL RE-KEY, NEW EPHM: %s\n",
1639 GNUNET_h2s ((struct GNUNET_HashCode *) &kx_msg.ephemeral_key));
1641 GNUNET_assert (GNUNET_OK ==
1642 GNUNET_CRYPTO_eddsa_sign (my_private_key,
1644 &kx_msg.signature));
1646 n = (long) GNUNET_CONTAINER_multipeermap_size (tunnels);
1647 GNUNET_CONTAINER_multipeermap_iterate (tunnels, &rekey_iterator, (void *) n);
1649 rekey_task = GNUNET_SCHEDULER_add_delayed (rekey_period, &rekey, NULL);
1654 * Called only on shutdown, destroy every tunnel.
1656 * @param cls Closure (unused).
1657 * @param key Current public key.
1658 * @param value Value in the hash map (tunnel).
1660 * @return #GNUNET_YES, so we should continue to iterate,
1663 destroy_iterator (void *cls,
1664 const struct GNUNET_PeerIdentity *key,
1667 struct CadetTunnel *t = value;
1669 LOG (GNUNET_ERROR_TYPE_DEBUG, "GCT_shutdown destroying tunnel at %p\n", t);
1676 * Notify remote peer that we don't know a channel he is talking about,
1677 * probably CHANNEL_DESTROY was missed.
1679 * @param t Tunnel on which to notify.
1680 * @param gid ID of the channel.
1683 send_channel_destroy (struct CadetTunnel *t, unsigned int gid)
1685 struct GNUNET_CADET_ChannelManage msg;
1687 msg.header.type = htons (GNUNET_MESSAGE_TYPE_CADET_CHANNEL_DESTROY);
1688 msg.header.size = htons (sizeof (msg));
1689 msg.chid = htonl (gid);
1691 LOG (GNUNET_ERROR_TYPE_DEBUG,
1692 "WARNING destroying unknown channel %u on tunnel %s\n",
1694 send_prebuilt_message (&msg.header, t, NULL, GNUNET_YES, NULL, NULL, NULL);
1699 * Demultiplex data per channel and call appropriate channel handler.
1701 * @param t Tunnel on which the data came.
1702 * @param msg Data message.
1703 * @param fwd Is this message fwd? This only is meaningful in loopback channels.
1704 * #GNUNET_YES if message is FWD on the respective channel (loopback)
1705 * #GNUNET_NO if message is BCK on the respective channel (loopback)
1706 * #GNUNET_SYSERR if message on a one-ended channel (remote)
1709 handle_data (struct CadetTunnel *t,
1710 const struct GNUNET_CADET_Data *msg,
1713 struct CadetChannel *ch;
1717 size = ntohs (msg->header.size);
1719 sizeof (struct GNUNET_CADET_Data) +
1720 sizeof (struct GNUNET_MessageHeader))
1725 LOG (GNUNET_ERROR_TYPE_DEBUG, " payload of type %s\n",
1726 GC_m2s (ntohs (msg[1].header.type)));
1729 ch = GCT_get_channel (t, ntohl (msg->chid));
1732 GNUNET_STATISTICS_update (stats, "# data on unknown channel",
1734 LOG (GNUNET_ERROR_TYPE_DEBUG, "WARNING channel 0x%X unknown\n",
1736 send_channel_destroy (t, ntohl (msg->chid));
1740 GCCH_handle_data (ch, msg, fwd);
1745 * Demultiplex data ACKs per channel and update appropriate channel buffer info.
1747 * @param t Tunnel on which the DATA ACK came.
1748 * @param msg DATA ACK message.
1749 * @param fwd Is this message fwd? This only is meaningful in loopback channels.
1750 * #GNUNET_YES if message is FWD on the respective channel (loopback)
1751 * #GNUNET_NO if message is BCK on the respective channel (loopback)
1752 * #GNUNET_SYSERR if message on a one-ended channel (remote)
1755 handle_data_ack (struct CadetTunnel *t,
1756 const struct GNUNET_CADET_DataACK *msg,
1759 struct CadetChannel *ch;
1763 size = ntohs (msg->header.size);
1764 if (size != sizeof (struct GNUNET_CADET_DataACK))
1771 ch = GCT_get_channel (t, ntohl (msg->chid));
1774 GNUNET_STATISTICS_update (stats, "# data ack on unknown channel",
1776 LOG (GNUNET_ERROR_TYPE_DEBUG, "WARNING channel %u unknown\n",
1781 GCCH_handle_data_ack (ch, msg, fwd);
1786 * Handle channel create.
1788 * @param t Tunnel on which the data came.
1789 * @param msg Data message.
1792 handle_ch_create (struct CadetTunnel *t,
1793 const struct GNUNET_CADET_ChannelCreate *msg)
1795 struct CadetChannel *ch;
1799 size = ntohs (msg->header.size);
1800 if (size != sizeof (struct GNUNET_CADET_ChannelCreate))
1807 ch = GCT_get_channel (t, ntohl (msg->chid));
1808 if (NULL != ch && ! GCT_is_loopback (t))
1810 /* Probably a retransmission, safe to ignore */
1811 LOG (GNUNET_ERROR_TYPE_DEBUG, " already exists...\n");
1813 ch = GCCH_handle_create (t, msg);
1815 GCT_add_channel (t, ch);
1821 * Handle channel NACK: check correctness and call channel handler for NACKs.
1823 * @param t Tunnel on which the NACK came.
1824 * @param msg NACK message.
1827 handle_ch_nack (struct CadetTunnel *t,
1828 const struct GNUNET_CADET_ChannelManage *msg)
1830 struct CadetChannel *ch;
1834 size = ntohs (msg->header.size);
1835 if (size != sizeof (struct GNUNET_CADET_ChannelManage))
1842 ch = GCT_get_channel (t, ntohl (msg->chid));
1845 GNUNET_STATISTICS_update (stats, "# channel NACK on unknown channel",
1847 LOG (GNUNET_ERROR_TYPE_DEBUG, "WARNING channel %u unknown\n",
1852 GCCH_handle_nack (ch);
1857 * Handle a CHANNEL ACK (SYNACK/ACK).
1859 * @param t Tunnel on which the CHANNEL ACK came.
1860 * @param msg CHANNEL ACK message.
1861 * @param fwd Is this message fwd? This only is meaningful in loopback channels.
1862 * #GNUNET_YES if message is FWD on the respective channel (loopback)
1863 * #GNUNET_NO if message is BCK on the respective channel (loopback)
1864 * #GNUNET_SYSERR if message on a one-ended channel (remote)
1867 handle_ch_ack (struct CadetTunnel *t,
1868 const struct GNUNET_CADET_ChannelManage *msg,
1871 struct CadetChannel *ch;
1875 size = ntohs (msg->header.size);
1876 if (size != sizeof (struct GNUNET_CADET_ChannelManage))
1883 ch = GCT_get_channel (t, ntohl (msg->chid));
1886 GNUNET_STATISTICS_update (stats, "# channel ack on unknown channel",
1888 LOG (GNUNET_ERROR_TYPE_DEBUG, "WARNING channel %u unknown\n",
1893 GCCH_handle_ack (ch, msg, fwd);
1898 * Handle a channel destruction message.
1900 * @param t Tunnel on which the message came.
1901 * @param msg Channel destroy message.
1902 * @param fwd Is this message fwd? This only is meaningful in loopback channels.
1903 * #GNUNET_YES if message is FWD on the respective channel (loopback)
1904 * #GNUNET_NO if message is BCK on the respective channel (loopback)
1905 * #GNUNET_SYSERR if message on a one-ended channel (remote)
1908 handle_ch_destroy (struct CadetTunnel *t,
1909 const struct GNUNET_CADET_ChannelManage *msg,
1912 struct CadetChannel *ch;
1916 size = ntohs (msg->header.size);
1917 if (size != sizeof (struct GNUNET_CADET_ChannelManage))
1924 ch = GCT_get_channel (t, ntohl (msg->chid));
1927 /* Probably a retransmission, safe to ignore */
1931 GCCH_handle_destroy (ch, msg, fwd);
1936 * The peer's ephemeral key has changed: update the symmetrical keys.
1938 * @param t Tunnel this message came on.
1939 * @param msg Key eXchange message.
1942 handle_ephemeral (struct CadetTunnel *t,
1943 const struct GNUNET_CADET_KX_Ephemeral *msg)
1945 LOG (GNUNET_ERROR_TYPE_INFO, "<=== EPHM for %s\n", GCT_2s (t));
1947 if (GNUNET_OK != check_ephemeral (t, msg))
1949 GNUNET_break_op (0);
1954 * If the key is different from what we know, derive the new E/D keys.
1955 * Else destroy the rekey ctx (duplicate EPHM after successful KX).
1957 if (0 != memcmp (&t->peers_ephemeral_key, &msg->ephemeral_key,
1958 sizeof (msg->ephemeral_key)))
1960 #if DUMP_KEYS_TO_STDERR
1961 LOG (GNUNET_ERROR_TYPE_INFO, "OLD: %s\n",
1962 GNUNET_h2s ((struct GNUNET_HashCode *) &t->peers_ephemeral_key));
1963 LOG (GNUNET_ERROR_TYPE_INFO, "NEW: %s\n",
1964 GNUNET_h2s ((struct GNUNET_HashCode *) &msg->ephemeral_key));
1966 t->peers_ephemeral_key = msg->ephemeral_key;
1970 if (CADET_TUNNEL_KEY_OK == t->estate)
1972 GCT_change_estate (t, CADET_TUNNEL_KEY_REKEY);
1974 if (NULL != t->rekey_task)
1975 GNUNET_SCHEDULER_cancel (t->rekey_task);
1976 t->rekey_task = GNUNET_SCHEDULER_add_now (rekey_tunnel, t);
1978 if (CADET_TUNNEL_KEY_SENT == t->estate)
1980 LOG (GNUNET_ERROR_TYPE_DEBUG, " our key was sent, sending challenge\n");
1982 GCT_change_estate (t, CADET_TUNNEL_KEY_PING);
1985 if (CADET_TUNNEL_KEY_UNINITIALIZED != ntohl(msg->sender_status))
1989 LOG (GNUNET_ERROR_TYPE_DEBUG, " recv nonce e %u\n", msg->nonce);
1990 t_decrypt (t, &nonce, &msg->nonce, ping_encryption_size (), msg->iv);
1991 LOG (GNUNET_ERROR_TYPE_DEBUG, " recv nonce c %u\n", nonce);
1992 send_pong (t, nonce);
1998 * Peer has answer to our challenge.
1999 * If answer is successful, consider the key exchange finished and clean
2000 * up all related state.
2002 * @param t Tunnel this message came on.
2003 * @param msg Key eXchange Pong message.
2006 handle_pong (struct CadetTunnel *t,
2007 const struct GNUNET_CADET_KX_Pong *msg)
2011 LOG (GNUNET_ERROR_TYPE_INFO, "<=== PONG for %s\n", GCT_2s (t));
2012 if (NULL == t->rekey_task)
2014 GNUNET_STATISTICS_update (stats, "# duplicate PONG messages", 1, GNUNET_NO);
2017 if (NULL == t->kx_ctx)
2019 GNUNET_STATISTICS_update (stats, "# stray PONG messages", 1, GNUNET_NO);
2023 t_decrypt (t, &challenge, &msg->nonce, sizeof (uint32_t), msg->iv);
2024 if (challenge != t->kx_ctx->challenge)
2026 LOG (GNUNET_ERROR_TYPE_WARNING, "Wrong PONG challenge on %s\n", GCT_2s (t));
2027 LOG (GNUNET_ERROR_TYPE_DEBUG, "PONG: %u (e: %u). Expected: %u.\n",
2028 challenge, msg->nonce, t->kx_ctx->challenge);
2032 GNUNET_SCHEDULER_cancel (t->rekey_task);
2033 t->rekey_task = NULL;
2035 /* Don't free the old keys right away, but after a delay.
2036 * Rationale: the KX could have happened over a very fast connection,
2037 * with payload traffic still signed with the old key stuck in a slower
2039 * Don't keep the keys longer than 1/4 the rekey period, and no longer than
2043 GCT_change_estate (t, CADET_TUNNEL_KEY_OK);
2048 * Demultiplex by message type and call appropriate handler for a message
2049 * towards a channel of a local tunnel.
2051 * @param t Tunnel this message came on.
2052 * @param msgh Message header.
2053 * @param fwd Is this message fwd? This only is meaningful in loopback channels.
2054 * #GNUNET_YES if message is FWD on the respective channel (loopback)
2055 * #GNUNET_NO if message is BCK on the respective channel (loopback)
2056 * #GNUNET_SYSERR if message on a one-ended channel (remote)
2059 handle_decrypted (struct CadetTunnel *t,
2060 const struct GNUNET_MessageHeader *msgh,
2065 type = ntohs (msgh->type);
2066 LOG (GNUNET_ERROR_TYPE_INFO, "<=== %s on %s\n", GC_m2s (type), GCT_2s (t));
2070 case GNUNET_MESSAGE_TYPE_CADET_KEEPALIVE:
2071 /* Do nothing, connection aleady got updated. */
2072 GNUNET_STATISTICS_update (stats, "# keepalives received", 1, GNUNET_NO);
2075 case GNUNET_MESSAGE_TYPE_CADET_DATA:
2076 /* Don't send hop ACK, wait for client to ACK */
2077 handle_data (t, (struct GNUNET_CADET_Data *) msgh, fwd);
2080 case GNUNET_MESSAGE_TYPE_CADET_DATA_ACK:
2081 handle_data_ack (t, (struct GNUNET_CADET_DataACK *) msgh, fwd);
2084 case GNUNET_MESSAGE_TYPE_CADET_CHANNEL_CREATE:
2085 handle_ch_create (t,
2086 (struct GNUNET_CADET_ChannelCreate *) msgh);
2089 case GNUNET_MESSAGE_TYPE_CADET_CHANNEL_NACK:
2091 (struct GNUNET_CADET_ChannelManage *) msgh);
2094 case GNUNET_MESSAGE_TYPE_CADET_CHANNEL_ACK:
2096 (struct GNUNET_CADET_ChannelManage *) msgh,
2100 case GNUNET_MESSAGE_TYPE_CADET_CHANNEL_DESTROY:
2101 handle_ch_destroy (t,
2102 (struct GNUNET_CADET_ChannelManage *) msgh,
2107 GNUNET_break_op (0);
2108 LOG (GNUNET_ERROR_TYPE_WARNING,
2109 "end-to-end message not known (%u)\n",
2110 ntohs (msgh->type));
2111 GCT_debug (t, GNUNET_ERROR_TYPE_WARNING);
2115 /******************************************************************************/
2116 /******************************** API ***********************************/
2117 /******************************************************************************/
2120 * Decrypt and demultiplex by message type. Call appropriate handler
2121 * for every message.
2123 * @param t Tunnel this message came on.
2124 * @param msg Encrypted message.
2127 GCT_handle_encrypted (struct CadetTunnel *t,
2128 const struct GNUNET_CADET_Encrypted *msg)
2130 size_t size = ntohs (msg->header.size);
2131 size_t payload_size = size - sizeof (struct GNUNET_CADET_Encrypted);
2133 char cbuf [payload_size];
2134 struct GNUNET_MessageHeader *msgh;
2137 decrypted_size = t_decrypt_and_validate (t, cbuf, &msg[1], payload_size,
2138 msg->iv, &msg->hmac);
2140 if (-1 == decrypted_size)
2142 GNUNET_break_op (0);
2147 while (off < decrypted_size)
2151 msgh = (struct GNUNET_MessageHeader *) &cbuf[off];
2152 msize = ntohs (msgh->size);
2153 if (msize < sizeof (struct GNUNET_MessageHeader))
2155 GNUNET_break_op (0);
2158 handle_decrypted (t, msgh, GNUNET_SYSERR);
2165 * Demultiplex an encapsulated KX message by message type.
2167 * @param t Tunnel on which the message came.
2168 * @param message Payload of KX message.
2171 GCT_handle_kx (struct CadetTunnel *t,
2172 const struct GNUNET_MessageHeader *message)
2176 type = ntohs (message->type);
2177 LOG (GNUNET_ERROR_TYPE_DEBUG, "kx message received\n", type);
2180 case GNUNET_MESSAGE_TYPE_CADET_KX_EPHEMERAL:
2181 handle_ephemeral (t, (struct GNUNET_CADET_KX_Ephemeral *) message);
2184 case GNUNET_MESSAGE_TYPE_CADET_KX_PONG:
2185 handle_pong (t, (struct GNUNET_CADET_KX_Pong *) message);
2189 GNUNET_break_op (0);
2190 LOG (GNUNET_ERROR_TYPE_DEBUG, "kx message not known (%u)\n", type);
2196 * Initialize the tunnel subsystem.
2198 * @param c Configuration handle.
2199 * @param key ECC private key, to derive all other keys and do crypto.
2202 GCT_init (const struct GNUNET_CONFIGURATION_Handle *c,
2203 const struct GNUNET_CRYPTO_EddsaPrivateKey *key)
2205 int expected_overhead;
2207 LOG (GNUNET_ERROR_TYPE_DEBUG, "init\n");
2209 expected_overhead = 0;
2210 expected_overhead += sizeof (struct GNUNET_CADET_Encrypted);
2211 expected_overhead += sizeof (struct GNUNET_CADET_Data);
2212 expected_overhead += sizeof (struct GNUNET_CADET_ACK);
2213 GNUNET_assert (GNUNET_CONSTANTS_CADET_P2P_OVERHEAD == expected_overhead);
2216 GNUNET_CONFIGURATION_get_value_number (c, "CADET", "DEFAULT_TTL",
2219 GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_WARNING,
2220 "CADET", "DEFAULT_TTL", "USING DEFAULT");
2224 GNUNET_CONFIGURATION_get_value_time (c, "CADET", "REKEY_PERIOD",
2227 rekey_period = GNUNET_TIME_UNIT_DAYS;
2230 my_private_key = key;
2231 kx_msg.header.size = htons (sizeof (kx_msg));
2232 kx_msg.header.type = htons (GNUNET_MESSAGE_TYPE_CADET_KX_EPHEMERAL);
2233 kx_msg.purpose.purpose = htonl (GNUNET_SIGNATURE_PURPOSE_CADET_KX);
2234 kx_msg.purpose.size = htonl (ephemeral_purpose_size ());
2235 kx_msg.origin_identity = my_full_id;
2236 rekey_task = GNUNET_SCHEDULER_add_now (&rekey, NULL);
2238 tunnels = GNUNET_CONTAINER_multipeermap_create (128, GNUNET_YES);
2243 * Shut down the tunnel subsystem.
2248 if (NULL != rekey_task)
2250 GNUNET_SCHEDULER_cancel (rekey_task);
2253 GNUNET_CONTAINER_multipeermap_iterate (tunnels, &destroy_iterator, NULL);
2254 GNUNET_CONTAINER_multipeermap_destroy (tunnels);
2261 * @param destination Peer this tunnel is towards.
2263 struct CadetTunnel *
2264 GCT_new (struct CadetPeer *destination)
2266 struct CadetTunnel *t;
2268 t = GNUNET_new (struct CadetTunnel);
2270 t->peer = destination;
2273 GNUNET_CONTAINER_multipeermap_put (tunnels, GCP_get_id (destination), t,
2274 GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_FAST))
2285 * Change the tunnel's connection state.
2287 * @param t Tunnel whose connection state to change.
2288 * @param cstate New connection state.
2291 GCT_change_cstate (struct CadetTunnel* t, enum CadetTunnelCState cstate)
2295 LOG (GNUNET_ERROR_TYPE_DEBUG, "Tunnel %s cstate %s => %s\n",
2296 GCP_2s (t->peer), cstate2s (t->cstate), cstate2s (cstate));
2297 if (myid != GCP_get_short_id (t->peer) &&
2298 CADET_TUNNEL_READY != t->cstate &&
2299 CADET_TUNNEL_READY == cstate)
2302 if (CADET_TUNNEL_KEY_OK == t->estate)
2304 LOG (GNUNET_ERROR_TYPE_DEBUG, " cstate triggered send queued data\n");
2305 send_queued_data (t);
2307 else if (CADET_TUNNEL_KEY_UNINITIALIZED == t->estate)
2309 LOG (GNUNET_ERROR_TYPE_DEBUG, " cstate triggered rekey\n");
2310 if (NULL != t->rekey_task)
2311 GNUNET_SCHEDULER_cancel (t->rekey_task);
2313 rekey_tunnel (t, NULL);
2318 if (CADET_TUNNEL_READY == cstate
2319 && CONNECTIONS_PER_TUNNEL <= GCT_count_connections (t))
2321 LOG (GNUNET_ERROR_TYPE_DEBUG, " cstate triggered stop dht\n");
2322 GCP_stop_search (t->peer);
2328 * Change the tunnel encryption state.
2330 * @param t Tunnel whose encryption state to change, or NULL.
2331 * @param state New encryption state.
2334 GCT_change_estate (struct CadetTunnel* t, enum CadetTunnelEState state)
2336 enum CadetTunnelEState old;
2343 LOG (GNUNET_ERROR_TYPE_DEBUG, "Tunnel %s estate was %s\n",
2344 GCP_2s (t->peer), estate2s (old));
2345 LOG (GNUNET_ERROR_TYPE_DEBUG, "Tunnel %s estate is now %s\n",
2346 GCP_2s (t->peer), estate2s (t->estate));
2348 /* Send queued data if enc state changes to OK */
2349 if (myid != GCP_get_short_id (t->peer) &&
2350 CADET_TUNNEL_KEY_OK != old && CADET_TUNNEL_KEY_OK == t->estate)
2352 send_queued_data (t);
2358 * @brief Check if tunnel has too many connections, and remove one if necessary.
2360 * Currently this means the newest connection, unless it is a direct one.
2361 * Implemented as a task to avoid freeing a connection that is in the middle
2362 * of being created/processed.
2364 * @param cls Closure (Tunnel to check).
2365 * @param tc Task context.
2368 trim_connections (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
2370 struct CadetTunnel *t = cls;
2372 t->trim_connections_task = NULL;
2374 if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
2377 if (GCT_count_connections (t) > 2 * CONNECTIONS_PER_TUNNEL)
2379 struct CadetTConnection *iter;
2380 struct CadetTConnection *c;
2382 for (c = iter = t->connection_head; NULL != iter; iter = iter->next)
2384 if ((iter->created.abs_value_us > c->created.abs_value_us)
2385 && GNUNET_NO == GCC_is_direct (iter->c))
2392 LOG (GNUNET_ERROR_TYPE_DEBUG, "Too many connections on tunnel %s\n",
2394 LOG (GNUNET_ERROR_TYPE_DEBUG, "Destroying connection %s\n",
2407 * Add a connection to a tunnel.
2410 * @param c Connection.
2413 GCT_add_connection (struct CadetTunnel *t, struct CadetConnection *c)
2415 struct CadetTConnection *aux;
2417 GNUNET_assert (NULL != c);
2419 LOG (GNUNET_ERROR_TYPE_DEBUG, "add connection %s\n", GCC_2s (c));
2420 LOG (GNUNET_ERROR_TYPE_DEBUG, " to tunnel %s\n", GCT_2s (t));
2421 for (aux = t->connection_head; aux != NULL; aux = aux->next)
2425 aux = GNUNET_new (struct CadetTConnection);
2427 aux->created = GNUNET_TIME_absolute_get ();
2429 GNUNET_CONTAINER_DLL_insert (t->connection_head, t->connection_tail, aux);
2431 if (CADET_TUNNEL_SEARCHING == t->cstate)
2432 GCT_change_estate (t, CADET_TUNNEL_WAITING);
2434 if (NULL != t->trim_connections_task)
2435 t->trim_connections_task = GNUNET_SCHEDULER_add_now (&trim_connections, t);
2440 * Remove a connection from a tunnel.
2443 * @param c Connection.
2446 GCT_remove_connection (struct CadetTunnel *t,
2447 struct CadetConnection *c)
2449 struct CadetTConnection *aux;
2450 struct CadetTConnection *next;
2453 LOG (GNUNET_ERROR_TYPE_DEBUG, "Removing connection %s from tunnel %s\n",
2454 GCC_2s (c), GCT_2s (t));
2455 for (aux = t->connection_head; aux != NULL; aux = next)
2460 GNUNET_CONTAINER_DLL_remove (t->connection_head, t->connection_tail, aux);
2465 conns = GCT_count_connections (t);
2467 && NULL == t->destroy_task
2468 && CADET_TUNNEL_SHUTDOWN != t->cstate
2469 && GNUNET_NO == shutting_down)
2471 if (0 == GCT_count_any_connections (t))
2472 GCT_change_cstate (t, CADET_TUNNEL_SEARCHING);
2474 GCT_change_cstate (t, CADET_TUNNEL_WAITING);
2477 /* Start new connections if needed */
2478 if (CONNECTIONS_PER_TUNNEL > conns
2479 && NULL == t->destroy_task
2480 && CADET_TUNNEL_SHUTDOWN != t->cstate
2481 && GNUNET_NO == shutting_down)
2483 LOG (GNUNET_ERROR_TYPE_DEBUG, " too few connections, getting new ones\n");
2484 GCP_connect (t->peer); /* Will change cstate to WAITING when possible */
2488 /* If not marked as ready, no change is needed */
2489 if (CADET_TUNNEL_READY != t->cstate)
2492 /* Check if any connection is ready to maintain cstate */
2493 for (aux = t->connection_head; aux != NULL; aux = aux->next)
2494 if (CADET_CONNECTION_READY == GCC_get_state (aux->c))
2500 * Add a channel to a tunnel.
2503 * @param ch Channel.
2506 GCT_add_channel (struct CadetTunnel *t, struct CadetChannel *ch)
2508 struct CadetTChannel *aux;
2510 GNUNET_assert (NULL != ch);
2512 LOG (GNUNET_ERROR_TYPE_DEBUG, "Adding channel %p to tunnel %p\n", ch, t);
2514 for (aux = t->channel_head; aux != NULL; aux = aux->next)
2516 LOG (GNUNET_ERROR_TYPE_DEBUG, " already there %p\n", aux->ch);
2521 aux = GNUNET_new (struct CadetTChannel);
2523 LOG (GNUNET_ERROR_TYPE_DEBUG, " adding %p to %p\n", aux, t->channel_head);
2524 GNUNET_CONTAINER_DLL_insert_tail (t->channel_head, t->channel_tail, aux);
2526 if (NULL != t->destroy_task)
2528 GNUNET_SCHEDULER_cancel (t->destroy_task);
2529 t->destroy_task = NULL;
2530 LOG (GNUNET_ERROR_TYPE_DEBUG, " undo destroy!\n");
2536 * Remove a channel from a tunnel.
2539 * @param ch Channel.
2542 GCT_remove_channel (struct CadetTunnel *t, struct CadetChannel *ch)
2544 struct CadetTChannel *aux;
2546 LOG (GNUNET_ERROR_TYPE_DEBUG, "Removing channel %p from tunnel %p\n", ch, t);
2547 for (aux = t->channel_head; aux != NULL; aux = aux->next)
2551 LOG (GNUNET_ERROR_TYPE_DEBUG, " found! %s\n", GCCH_2s (ch));
2552 GNUNET_CONTAINER_DLL_remove (t->channel_head, t->channel_tail, aux);
2561 * Search for a channel by global ID.
2563 * @param t Tunnel containing the channel.
2564 * @param chid Public channel number.
2566 * @return channel handler, NULL if doesn't exist
2568 struct CadetChannel *
2569 GCT_get_channel (struct CadetTunnel *t, CADET_ChannelNumber chid)
2571 struct CadetTChannel *iter;
2576 for (iter = t->channel_head; NULL != iter; iter = iter->next)
2578 if (GCCH_get_id (iter->ch) == chid)
2582 return NULL == iter ? NULL : iter->ch;
2587 * @brief Destroy a tunnel and free all resources.
2589 * Should only be called a while after the tunnel has been marked as destroyed,
2590 * in case there is a new channel added to the same peer shortly after marking
2591 * the tunnel. This way we avoid a new public key handshake.
2593 * @param cls Closure (tunnel to destroy).
2594 * @param tc Task context.
2597 delayed_destroy (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
2599 struct CadetTunnel *t = cls;
2600 struct CadetTConnection *iter;
2602 LOG (GNUNET_ERROR_TYPE_DEBUG, "delayed destroying tunnel %p\n", t);
2603 if (0 != (GNUNET_SCHEDULER_REASON_SHUTDOWN & tc->reason))
2605 LOG (GNUNET_ERROR_TYPE_WARNING,
2606 "Not destroying tunnel, due to shutdown. "
2607 "Tunnel at %p should have been freed by GCT_shutdown\n", t);
2610 t->destroy_task = NULL;
2611 t->cstate = CADET_TUNNEL_SHUTDOWN;
2613 for (iter = t->connection_head; NULL != iter; iter = iter->next)
2615 GCC_send_destroy (iter->c);
2622 * Tunnel is empty: destroy it.
2624 * Notifies all connections about the destruction.
2626 * @param t Tunnel to destroy.
2629 GCT_destroy_empty (struct CadetTunnel *t)
2631 if (GNUNET_YES == shutting_down)
2632 return; /* Will be destroyed immediately anyway */
2634 if (NULL != t->destroy_task)
2636 LOG (GNUNET_ERROR_TYPE_WARNING,
2637 "Tunnel %s is already scheduled for destruction. Tunnel debug dump:\n",
2639 GCT_debug (t, GNUNET_ERROR_TYPE_WARNING);
2641 /* should never happen, tunnel can only become empty once, and the
2642 * task identifier should be NO_TASK (cleaned when the tunnel was created
2643 * or became un-empty)
2648 LOG (GNUNET_ERROR_TYPE_DEBUG, "Tunnel %s empty: scheduling destruction\n",
2651 // FIXME make delay a config option
2652 t->destroy_task = GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_MINUTES,
2653 &delayed_destroy, t);
2654 LOG (GNUNET_ERROR_TYPE_DEBUG, "Scheduled destroy of %p as %llu\n",
2655 t, t->destroy_task);
2660 * Destroy tunnel if empty (no more channels).
2662 * @param t Tunnel to destroy if empty.
2665 GCT_destroy_if_empty (struct CadetTunnel *t)
2667 LOG (GNUNET_ERROR_TYPE_DEBUG, "Tunnel %s destroy if empty\n", GCT_2s (t));
2668 if (0 < GCT_count_channels (t))
2671 GCT_destroy_empty (t);
2676 * Destroy the tunnel.
2678 * This function does not generate any warning traffic to clients or peers.
2681 * Cancel messages belonging to this tunnel queued to neighbors.
2682 * Free any allocated resources linked to the tunnel.
2684 * @param t The tunnel to destroy.
2687 GCT_destroy (struct CadetTunnel *t)
2689 struct CadetTConnection *iter_c;
2690 struct CadetTConnection *next_c;
2691 struct CadetTChannel *iter_ch;
2692 struct CadetTChannel *next_ch;
2697 LOG (GNUNET_ERROR_TYPE_DEBUG, "destroying tunnel %s\n", GCP_2s (t->peer));
2699 GNUNET_break (GNUNET_YES ==
2700 GNUNET_CONTAINER_multipeermap_remove (tunnels,
2701 GCP_get_id (t->peer), t));
2703 for (iter_c = t->connection_head; NULL != iter_c; iter_c = next_c)
2705 next_c = iter_c->next;
2706 GCC_destroy (iter_c->c);
2708 for (iter_ch = t->channel_head; NULL != iter_ch; iter_ch = next_ch)
2710 next_ch = iter_ch->next;
2711 GCCH_destroy (iter_ch->ch);
2712 /* Should only happen on shutdown, but it's ok. */
2715 if (NULL != t->destroy_task)
2717 LOG (GNUNET_ERROR_TYPE_DEBUG, "cancelling dest: %llX\n", t->destroy_task);
2718 GNUNET_SCHEDULER_cancel (t->destroy_task);
2719 t->destroy_task = NULL;
2722 if (NULL != t->trim_connections_task)
2724 LOG (GNUNET_ERROR_TYPE_DEBUG, "cancelling trim: %llX\n",
2725 t->trim_connections_task);
2726 GNUNET_SCHEDULER_cancel (t->trim_connections_task);
2727 t->trim_connections_task = NULL;
2730 GNUNET_STATISTICS_update (stats, "# tunnels", -1, GNUNET_NO);
2731 GCP_set_tunnel (t->peer, NULL);
2733 if (NULL != t->rekey_task)
2735 GNUNET_SCHEDULER_cancel (t->rekey_task);
2736 t->rekey_task = NULL;
2738 if (NULL != t->kx_ctx)
2740 if (NULL != t->kx_ctx->finish_task)
2741 GNUNET_SCHEDULER_cancel (t->kx_ctx->finish_task);
2742 GNUNET_free (t->kx_ctx);
2749 * @brief Use the given path for the tunnel.
2750 * Update the next and prev hops (and RCs).
2751 * (Re)start the path refresh in case the tunnel is locally owned.
2753 * @param t Tunnel to update.
2754 * @param p Path to use.
2756 * @return Connection created.
2758 struct CadetConnection *
2759 GCT_use_path (struct CadetTunnel *t, struct CadetPeerPath *p)
2761 struct CadetConnection *c;
2762 struct GNUNET_CADET_Hash cid;
2763 unsigned int own_pos;
2765 if (NULL == t || NULL == p)
2771 if (CADET_TUNNEL_SHUTDOWN == t->cstate)
2777 for (own_pos = 0; own_pos < p->length; own_pos++)
2779 if (p->peers[own_pos] == myid)
2782 if (own_pos >= p->length)
2784 GNUNET_break_op (0);
2788 GNUNET_CRYPTO_random_block (GNUNET_CRYPTO_QUALITY_NONCE, &cid, sizeof (cid));
2789 c = GCC_new (&cid, t, p, own_pos);
2792 /* Path was flawed */
2795 GCT_add_connection (t, c);
2801 * Count all created connections of a tunnel. Not necessarily ready connections!
2803 * @param t Tunnel on which to count.
2805 * @return Number of connections created, either being established or ready.
2808 GCT_count_any_connections (struct CadetTunnel *t)
2810 struct CadetTConnection *iter;
2816 for (count = 0, iter = t->connection_head; NULL != iter; iter = iter->next)
2824 * Count established (ready) connections of a tunnel.
2826 * @param t Tunnel on which to count.
2828 * @return Number of connections.
2831 GCT_count_connections (struct CadetTunnel *t)
2833 struct CadetTConnection *iter;
2839 for (count = 0, iter = t->connection_head; NULL != iter; iter = iter->next)
2840 if (CADET_CONNECTION_READY == GCC_get_state (iter->c))
2848 * Count channels of a tunnel.
2850 * @param t Tunnel on which to count.
2852 * @return Number of channels.
2855 GCT_count_channels (struct CadetTunnel *t)
2857 struct CadetTChannel *iter;
2860 for (count = 0, iter = t->channel_head;
2862 iter = iter->next, count++) /* skip */;
2869 * Get the connectivity state of a tunnel.
2873 * @return Tunnel's connectivity state.
2875 enum CadetTunnelCState
2876 GCT_get_cstate (struct CadetTunnel *t)
2881 return (enum CadetTunnelCState) -1;
2888 * Get the encryption state of a tunnel.
2892 * @return Tunnel's encryption state.
2894 enum CadetTunnelEState
2895 GCT_get_estate (struct CadetTunnel *t)
2900 return (enum CadetTunnelEState) -1;
2906 * Get the maximum buffer space for a tunnel towards a local client.
2910 * @return Biggest buffer space offered by any channel in the tunnel.
2913 GCT_get_channels_buffer (struct CadetTunnel *t)
2915 struct CadetTChannel *iter;
2916 unsigned int buffer;
2917 unsigned int ch_buf;
2919 if (NULL == t->channel_head)
2921 /* Probably getting buffer for a channel create/handshake. */
2922 LOG (GNUNET_ERROR_TYPE_DEBUG, " no channels, allow max\n");
2927 for (iter = t->channel_head; NULL != iter; iter = iter->next)
2929 ch_buf = get_channel_buffer (iter);
2930 if (ch_buf > buffer)
2938 * Get the total buffer space for a tunnel for P2P traffic.
2942 * @return Buffer space offered by all connections in the tunnel.
2945 GCT_get_connections_buffer (struct CadetTunnel *t)
2947 struct CadetTConnection *iter;
2948 unsigned int buffer;
2950 if (GNUNET_NO == is_ready (t))
2952 if (count_queued_data (t) > 3)
2959 for (iter = t->connection_head; NULL != iter; iter = iter->next)
2961 if (GCC_get_state (iter->c) != CADET_CONNECTION_READY)
2965 buffer += get_connection_buffer (iter);
2973 * Get the tunnel's destination.
2977 * @return ID of the destination peer.
2979 const struct GNUNET_PeerIdentity *
2980 GCT_get_destination (struct CadetTunnel *t)
2982 return GCP_get_id (t->peer);
2987 * Get the tunnel's next free global channel ID.
2991 * @return GID of a channel free to use.
2994 GCT_get_next_chid (struct CadetTunnel *t)
2996 CADET_ChannelNumber chid;
2997 CADET_ChannelNumber mask;
3000 /* Set bit 30 depending on the ID relationship. Bit 31 is always 0 for GID.
3001 * If our ID is bigger or loopback tunnel, start at 0, bit 30 = 0
3002 * If peer's ID is bigger, start at 0x4... bit 30 = 1
3004 result = GNUNET_CRYPTO_cmp_peer_identity (&my_full_id, GCP_get_id (t->peer));
3009 t->next_chid |= mask;
3011 while (NULL != GCT_get_channel (t, t->next_chid))
3013 LOG (GNUNET_ERROR_TYPE_DEBUG, "Channel %u exists...\n", t->next_chid);
3014 t->next_chid = (t->next_chid + 1) & ~GNUNET_CADET_LOCAL_CHANNEL_ID_CLI;
3015 t->next_chid |= mask;
3017 chid = t->next_chid;
3018 t->next_chid = (t->next_chid + 1) & ~GNUNET_CADET_LOCAL_CHANNEL_ID_CLI;
3019 t->next_chid |= mask;
3026 * Send ACK on one or more channels due to buffer in connections.
3028 * @param t Channel which has some free buffer space.
3031 GCT_unchoke_channels (struct CadetTunnel *t)
3033 struct CadetTChannel *iter;
3034 unsigned int buffer;
3035 unsigned int channels = GCT_count_channels (t);
3036 unsigned int choked_n;
3037 struct CadetChannel *choked[channels];
3039 LOG (GNUNET_ERROR_TYPE_DEBUG, "GCT_unchoke_channels on %s\n", GCT_2s (t));
3040 LOG (GNUNET_ERROR_TYPE_DEBUG, " head: %p\n", t->channel_head);
3041 if (NULL != t->channel_head)
3042 LOG (GNUNET_ERROR_TYPE_DEBUG, " head ch: %p\n", t->channel_head->ch);
3044 /* Get buffer space */
3045 buffer = GCT_get_connections_buffer (t);
3051 /* Count and remember choked channels */
3053 for (iter = t->channel_head; NULL != iter; iter = iter->next)
3055 if (GNUNET_NO == get_channel_allowed (iter))
3057 choked[choked_n++] = iter->ch;
3061 /* Unchoke random channels */
3062 while (0 < buffer && 0 < choked_n)
3064 unsigned int r = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK,
3066 GCCH_allow_client (choked[r], GCCH_is_origin (choked[r], GNUNET_YES));
3069 choked[r] = choked[choked_n];
3075 * Send ACK on one or more connections due to buffer space to the client.
3077 * Iterates all connections of the tunnel and sends ACKs appropriately.
3082 GCT_send_connection_acks (struct CadetTunnel *t)
3084 struct CadetTConnection *iter;
3087 uint32_t allow_per_connection;
3089 unsigned int buffer;
3091 LOG (GNUNET_ERROR_TYPE_DEBUG, "Tunnel send connection ACKs on %s\n",
3100 if (CADET_TUNNEL_READY != t->cstate)
3103 buffer = GCT_get_channels_buffer (t);
3104 LOG (GNUNET_ERROR_TYPE_DEBUG, " buffer %u\n", buffer);
3106 /* Count connections, how many messages are already allowed */
3107 cs = GCT_count_connections (t);
3108 for (allowed = 0, iter = t->connection_head; NULL != iter; iter = iter->next)
3110 allowed += get_connection_allowed (iter);
3112 LOG (GNUNET_ERROR_TYPE_DEBUG, " allowed %u\n", allowed);
3114 /* Make sure there is no overflow */
3115 if (allowed > buffer)
3118 /* Authorize connections to send more data */
3119 to_allow = buffer - allowed;
3121 for (iter = t->connection_head;
3122 NULL != iter && to_allow > 0;
3125 if (CADET_CONNECTION_READY != GCC_get_state (iter->c)
3126 || get_connection_allowed (iter) > 64 / 3)
3130 allow_per_connection = to_allow/cs;
3131 to_allow -= allow_per_connection;
3133 GCC_allow (iter->c, allow_per_connection,
3134 GCC_is_origin (iter->c, GNUNET_NO));
3139 /* Since we don't allow if it's allowed to send 64/3, this can happen. */
3140 LOG (GNUNET_ERROR_TYPE_DEBUG, " reminding to_allow: %u\n", to_allow);
3146 * Cancel a previously sent message while it's in the queue.
3148 * ONLY can be called before the continuation given to the send function
3149 * is called. Once the continuation is called, the message is no longer in the
3152 * @param q Handle to the queue.
3155 GCT_cancel (struct CadetTunnelQueue *q)
3160 /* tun_message_sent() will be called and free q */
3162 else if (NULL != q->tqd)
3164 unqueue_data (q->tqd);
3166 if (NULL != q->cont)
3167 q->cont (q->cont_cls, NULL, q, 0, 0);
3178 * Sends an already built message on a tunnel, encrypting it and
3179 * choosing the best connection if not provided.
3181 * @param message Message to send. Function modifies it.
3182 * @param t Tunnel on which this message is transmitted.
3183 * @param c Connection to use (autoselect if NULL).
3184 * @param force Force the tunnel to take the message (buffer overfill).
3185 * @param cont Continuation to call once message is really sent.
3186 * @param cont_cls Closure for @c cont.
3188 * @return Handle to cancel message. NULL if @c cont is NULL.
3190 struct CadetTunnelQueue *
3191 GCT_send_prebuilt_message (const struct GNUNET_MessageHeader *message,
3192 struct CadetTunnel *t, struct CadetConnection *c,
3193 int force, GCT_sent cont, void *cont_cls)
3195 return send_prebuilt_message (message, t, c, force, cont, cont_cls, NULL);
3199 * Sends an already built and encrypted message on a tunnel, choosing the best
3200 * connection. Useful for re-queueing messages queued on a destroyed connection.
3202 * @param message Message to send. Function modifies it.
3203 * @param t Tunnel on which this message is transmitted.
3206 GCT_resend_message (const struct GNUNET_MessageHeader *message,
3207 struct CadetTunnel *t)
3209 struct CadetConnection *c;
3212 c = tunnel_get_connection (t);
3215 /* TODO queue in tunnel, marked as encrypted */
3216 LOG (GNUNET_ERROR_TYPE_DEBUG, "No connection available, dropping.\n");
3219 fwd = GCC_is_origin (c, GNUNET_YES);
3220 GNUNET_break (NULL == GCC_send_prebuilt_message (message, 0, 0, c, fwd,
3221 GNUNET_YES, NULL, NULL));
3226 * Is the tunnel directed towards the local peer?
3230 * @return #GNUNET_YES if it is loopback.
3233 GCT_is_loopback (const struct CadetTunnel *t)
3235 return (myid == GCP_get_short_id (t->peer));
3240 * Is the tunnel this path already?
3245 * @return #GNUNET_YES a connection uses this path.
3248 GCT_is_path_used (const struct CadetTunnel *t, const struct CadetPeerPath *p)
3250 struct CadetTConnection *iter;
3252 for (iter = t->connection_head; NULL != iter; iter = iter->next)
3253 if (path_equivalent (GCC_get_path (iter->c), p))
3261 * Get a cost of a path for a tunnel considering existing connections.
3264 * @param path Candidate path.
3266 * @return Cost of the path (path length + number of overlapping nodes)
3269 GCT_get_path_cost (const struct CadetTunnel *t,
3270 const struct CadetPeerPath *path)
3272 struct CadetTConnection *iter;
3273 const struct CadetPeerPath *aux;
3274 unsigned int overlap;
3282 GNUNET_assert (NULL != t);
3284 for (i = 0; i < path->length; i++)
3286 for (iter = t->connection_head; NULL != iter; iter = iter->next)
3288 aux = GCC_get_path (iter->c);
3292 for (j = 0; j < aux->length; j++)
3294 if (path->peers[i] == aux->peers[j])
3302 return path->length + overlap;
3307 * Get the static string for the peer this tunnel is directed.
3311 * @return Static string the destination peer's ID.
3314 GCT_2s (const struct CadetTunnel *t)
3319 return GCP_2s (t->peer);
3323 /******************************************************************************/
3324 /***************************** INFO/DEBUG *******************************/
3325 /******************************************************************************/
3328 * Log all possible info about the tunnel state.
3330 * @param t Tunnel to debug.
3331 * @param level Debug level to use.
3334 GCT_debug (const struct CadetTunnel *t, enum GNUNET_ErrorType level)
3336 struct CadetTChannel *iterch;
3337 struct CadetTConnection *iterc;
3340 do_log = GNUNET_get_log_call_status (level & (~GNUNET_ERROR_TYPE_BULK),
3342 __FILE__, __FUNCTION__, __LINE__);
3346 LOG2 (level, "TTT DEBUG TUNNEL TOWARDS %s\n", GCT_2s (t));
3347 LOG2 (level, "TTT cstate %s, estate %s\n",
3348 cstate2s (t->cstate), estate2s (t->estate));
3349 LOG2 (level, "TTT kx_ctx %p, rekey_task %u, finish task %u\n",
3350 t->kx_ctx, t->rekey_task, t->kx_ctx ? t->kx_ctx->finish_task : 0);
3351 #if DUMP_KEYS_TO_STDERR
3352 LOG2 (level, "TTT my EPHM\t %s\n",
3353 GNUNET_h2s ((struct GNUNET_HashCode *) &kx_msg.ephemeral_key));
3354 LOG2 (level, "TTT peers EPHM:\t %s\n",
3355 GNUNET_h2s ((struct GNUNET_HashCode *) &t->peers_ephemeral_key));
3356 LOG2 (level, "TTT ENC key:\t %s\n",
3357 GNUNET_h2s ((struct GNUNET_HashCode *) &t->e_key));
3358 LOG2 (level, "TTT DEC key:\t %s\n",
3359 GNUNET_h2s ((struct GNUNET_HashCode *) &t->d_key));
3362 LOG2 (level, "TTT OLD ENC key:\t %s\n",
3363 GNUNET_h2s ((struct GNUNET_HashCode *) &t->kx_ctx->e_key_old));
3364 LOG2 (level, "TTT OLD DEC key:\t %s\n",
3365 GNUNET_h2s ((struct GNUNET_HashCode *) &t->kx_ctx->d_key_old));
3368 LOG2 (level, "TTT tq_head %p, tq_tail %p\n", t->tq_head, t->tq_tail);
3369 LOG2 (level, "TTT destroy %u\n", t->destroy_task);
3371 LOG2 (level, "TTT channels:\n");
3372 for (iterch = t->channel_head; NULL != iterch; iterch = iterch->next)
3374 LOG2 (level, "TTT - %s\n", GCCH_2s (iterch->ch));
3377 LOG2 (level, "TTT connections:\n");
3378 for (iterc = t->connection_head; NULL != iterc; iterc = iterc->next)
3380 GCC_debug (iterc->c, level);
3383 LOG2 (level, "TTT DEBUG TUNNEL END\n");
3388 * Iterate all tunnels.
3390 * @param iter Iterator.
3391 * @param cls Closure for @c iter.
3394 GCT_iterate_all (GNUNET_CONTAINER_PeerMapIterator iter, void *cls)
3396 GNUNET_CONTAINER_multipeermap_iterate (tunnels, iter, cls);
3401 * Count all tunnels.
3403 * @return Number of tunnels to remote peers kept by this peer.
3406 GCT_count_all (void)
3408 return GNUNET_CONTAINER_multipeermap_size (tunnels);
3413 * Iterate all connections of a tunnel.
3415 * @param t Tunnel whose connections to iterate.
3416 * @param iter Iterator.
3417 * @param cls Closure for @c iter.
3420 GCT_iterate_connections (struct CadetTunnel *t, GCT_conn_iter iter, void *cls)
3422 struct CadetTConnection *ct;
3424 for (ct = t->connection_head; NULL != ct; ct = ct->next)
3430 * Iterate all channels of a tunnel.
3432 * @param t Tunnel whose channels to iterate.
3433 * @param iter Iterator.
3434 * @param cls Closure for @c iter.
3437 GCT_iterate_channels (struct CadetTunnel *t, GCT_chan_iter iter, void *cls)
3439 struct CadetTChannel *cht;
3441 for (cht = t->channel_head; NULL != cht; cht = cht->next)
3442 iter (cls, cht->ch);