/* This file is part of GNUnet. (C) 2013 Christian Grothoff (and other contributing authors) GNUnet is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version. GNUnet is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with GNUnet; see the file COPYING. If not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #include "platform.h" #include "gnunet_util_lib.h" #include "gnunet_signatures.h" #include "gnunet_statistics_service.h" #include "cadet_protocol.h" #include "cadet_path.h" #include "gnunet-service-cadet_tunnel.h" #include "gnunet-service-cadet_connection.h" #include "gnunet-service-cadet_channel.h" #include "gnunet-service-cadet_peer.h" #define LOG(level, ...) GNUNET_log_from(level,"cadet-tun",__VA_ARGS__) #define LOG2(level, ...) GNUNET_log_from_nocheck(level,"cadet-tun",__VA_ARGS__) #define REKEY_WAIT GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_SECONDS, 5) #define CONNECTIONS_PER_TUNNEL 3 #if !defined(GNUNET_CULL_LOGGING) #define DUMP_KEYS_TO_STDERR GNUNET_YES #else #define DUMP_KEYS_TO_STDERR GNUNET_NO #endif /******************************************************************************/ /******************************** STRUCTS **********************************/ /******************************************************************************/ struct CadetTChannel { struct CadetTChannel *next; struct CadetTChannel *prev; struct CadetChannel *ch; }; /** * Connection list and metadata. */ struct CadetTConnection { /** * Next in DLL. */ struct CadetTConnection *next; /** * Prev in DLL. */ struct CadetTConnection *prev; /** * Connection handle. */ struct CadetConnection *c; /** * Creation time, to keep oldest connection alive. */ struct GNUNET_TIME_Absolute created; /** * Connection throughput, to keep fastest connection alive. */ uint32_t throughput; }; /** * Structure used during a Key eXchange. */ struct CadetTunnelKXCtx { /** * Encryption ("our") old "confirmed" key, for encrypting traffic sent by us * end before the key exchange is finished or times out. */ struct GNUNET_CRYPTO_SymmetricSessionKey e_key_old; /** * Decryption ("their") old "confirmed" key, for decrypting traffic sent by * the other end before the key exchange started. */ struct GNUNET_CRYPTO_SymmetricSessionKey d_key_old; /** * Challenge to send in a ping and expect in the pong. */ uint32_t challenge; /** * When the rekey started. One minute after this the new key will be used. */ struct GNUNET_TIME_Absolute rekey_start_time; /** * Task for delayed destruction of the Key eXchange context, to allow delayed * messages with the old key to be decrypted successfully. */ GNUNET_SCHEDULER_TaskIdentifier finish_task; }; /** * Struct containing all information regarding a tunnel to a peer. */ struct CadetTunnel { /** * Endpoint of the tunnel. */ struct CadetPeer *peer; /** * State of the tunnel connectivity. */ enum CadetTunnelCState cstate; /** * State of the tunnel encryption. */ enum CadetTunnelEState estate; /** * Key eXchange context. */ struct CadetTunnelKXCtx *kx_ctx; /** * Peer's ephemeral key, to recreate @c e_key and @c d_key when own ephemeral * key changes. */ struct GNUNET_CRYPTO_EcdhePublicKey peers_ephemeral_key; /** * Encryption ("our") key. It is only "confirmed" if kx_ctx is NULL. */ struct GNUNET_CRYPTO_SymmetricSessionKey e_key; /** * Decryption ("their") key. It is only "confirmed" if kx_ctx is NULL. */ struct GNUNET_CRYPTO_SymmetricSessionKey d_key; /** * Task to start the rekey process. */ GNUNET_SCHEDULER_TaskIdentifier rekey_task; /** * Paths that are actively used to reach the destination peer. */ struct CadetTConnection *connection_head; struct CadetTConnection *connection_tail; /** * Next connection number. */ uint32_t next_cid; /** * Channels inside this tunnel. */ struct CadetTChannel *channel_head; struct CadetTChannel *channel_tail; /** * Channel ID for the next created channel. */ CADET_ChannelNumber next_chid; /** * Destroy flag: if true, destroy on last message. */ GNUNET_SCHEDULER_TaskIdentifier destroy_task; /** * Queued messages, to transmit once tunnel gets connected. */ struct CadetTunnelDelayed *tq_head; struct CadetTunnelDelayed *tq_tail; /** * Task to trim connections if too many are present. */ GNUNET_SCHEDULER_TaskIdentifier trim_connections_task; }; /** * Struct used to save messages in a non-ready tunnel to send once connected. */ struct CadetTunnelDelayed { /** * DLL */ struct CadetTunnelDelayed *next; struct CadetTunnelDelayed *prev; /** * Tunnel. */ struct CadetTunnel *t; /** * Tunnel queue given to the channel to cancel request. Update on send_queued. */ struct CadetTunnelQueue *tq; /** * Message to send. */ /* struct GNUNET_MessageHeader *msg; */ }; /** * Handle for messages queued but not yet sent. */ struct CadetTunnelQueue { /** * Connection queue handle, to cancel if necessary. */ struct CadetConnectionQueue *cq; /** * Handle in case message hasn't been given to a connection yet. */ struct CadetTunnelDelayed *tqd; /** * Continuation to call once sent. */ GCT_sent cont; /** * Closure for @c cont. */ void *cont_cls; }; /******************************************************************************/ /******************************* GLOBALS ***********************************/ /******************************************************************************/ /** * Global handle to the statistics service. */ extern struct GNUNET_STATISTICS_Handle *stats; /** * Local peer own ID (memory efficient handle). */ extern GNUNET_PEER_Id myid; /** * Local peer own ID (full value). */ extern struct GNUNET_PeerIdentity my_full_id; /** * Don't try to recover tunnels if shutting down. */ extern int shutting_down; /** * Set of all tunnels, in order to trigger a new exchange on rekey. * Indexed by peer's ID. */ static struct GNUNET_CONTAINER_MultiPeerMap *tunnels; /** * Default TTL for payload packets. */ static unsigned long long default_ttl; /** * Own private key. */ const static struct GNUNET_CRYPTO_EddsaPrivateKey *my_private_key; /** * Own ephemeral private key. */ static struct GNUNET_CRYPTO_EcdhePrivateKey *my_ephemeral_key; /** * Cached message used to perform a key exchange. */ static struct GNUNET_CADET_KX_Ephemeral kx_msg; /** * Task to generate a new ephemeral key. */ static GNUNET_SCHEDULER_TaskIdentifier rekey_task; /** * Rekey period. */ static struct GNUNET_TIME_Relative rekey_period; /******************************************************************************/ /******************************** STATIC ***********************************/ /******************************************************************************/ /** * Get string description for tunnel connectivity state. * * @param cs Tunnel state. * * @return String representation. */ static const char * cstate2s (enum CadetTunnelCState cs) { static char buf[32]; switch (cs) { case CADET_TUNNEL_NEW: return "CADET_TUNNEL_NEW"; case CADET_TUNNEL_SEARCHING: return "CADET_TUNNEL_SEARCHING"; case CADET_TUNNEL_WAITING: return "CADET_TUNNEL_WAITING"; case CADET_TUNNEL_READY: return "CADET_TUNNEL_READY"; case CADET_TUNNEL_SHUTDOWN: return "CADET_TUNNEL_SHUTDOWN"; default: SPRINTF (buf, "%u (UNKNOWN STATE)", cs); return buf; } return ""; } /** * Get string description for tunnel encryption state. * * @param es Tunnel state. * * @return String representation. */ static const char * estate2s (enum CadetTunnelEState es) { static char buf[32]; switch (es) { case CADET_TUNNEL_KEY_UNINITIALIZED: return "CADET_TUNNEL_KEY_UNINITIALIZED"; case CADET_TUNNEL_KEY_SENT: return "CADET_TUNNEL_KEY_SENT"; case CADET_TUNNEL_KEY_PING: return "CADET_TUNNEL_KEY_PING"; case CADET_TUNNEL_KEY_OK: return "CADET_TUNNEL_KEY_OK"; case CADET_TUNNEL_KEY_REKEY: return "CADET_TUNNEL_KEY_REKEY"; default: SPRINTF (buf, "%u (UNKNOWN STATE)", es); return buf; } return ""; } /** * @brief Check if tunnel is ready to send traffic. * * Tunnel must be connected and with encryption correctly set up. * * @param t Tunnel to check. * * @return #GNUNET_YES if ready, #GNUNET_NO otherwise */ static int is_ready (struct CadetTunnel *t) { int ready; GCT_debug (t, GNUNET_ERROR_TYPE_DEBUG); ready = CADET_TUNNEL_READY == t->cstate && (CADET_TUNNEL_KEY_OK == t->estate || CADET_TUNNEL_KEY_REKEY == t->estate); ready = ready || GCT_is_loopback (t); return ready; } /** * Check if a key is invalid (NULL pointer or all 0) * * @param key Key to check. * * @return #GNUNET_YES if key is null, #GNUNET_NO if exists and is not 0. */ static int is_key_null (struct GNUNET_CRYPTO_SymmetricSessionKey *key) { struct GNUNET_CRYPTO_SymmetricSessionKey null_key; if (NULL == key) return GNUNET_YES; memset (&null_key, 0, sizeof (null_key)); if (0 == memcmp (key, &null_key, sizeof (null_key))) return GNUNET_YES; return GNUNET_NO; } /** * Ephemeral key message purpose size. * * @return Size of the part of the ephemeral key message that must be signed. */ size_t ephemeral_purpose_size (void) { return sizeof (struct GNUNET_CRYPTO_EccSignaturePurpose) + sizeof (struct GNUNET_TIME_AbsoluteNBO) + sizeof (struct GNUNET_TIME_AbsoluteNBO) + sizeof (struct GNUNET_CRYPTO_EcdhePublicKey) + sizeof (struct GNUNET_PeerIdentity); } /** * Size of the encrypted part of a ping message. * * @return Size of the encrypted part of a ping message. */ size_t ping_encryption_size (void) { return sizeof (struct GNUNET_PeerIdentity) + sizeof (uint32_t); } /** * Get the channel's buffer. ONLY FOR NON-LOOPBACK CHANNELS!! * * @param tch Tunnel's channel handle. * * @return Amount of messages the channel can still buffer towards the client. */ static unsigned int get_channel_buffer (const struct CadetTChannel *tch) { int fwd; /* If channel is outgoing, is origin in the FWD direction and fwd is YES */ fwd = GCCH_is_origin (tch->ch, GNUNET_YES); return GCCH_get_buffer (tch->ch, fwd); } /** * Get the channel's allowance status. * * @param tch Tunnel's channel handle. * * @return #GNUNET_YES if we allowed the client to send data to us. */ static int get_channel_allowed (const struct CadetTChannel *tch) { int fwd; /* If channel is outgoing, is origin in the FWD direction and fwd is YES */ fwd = GCCH_is_origin (tch->ch, GNUNET_YES); return GCCH_get_allowed (tch->ch, fwd); } /** * Get the connection's buffer. * * @param tc Tunnel's connection handle. * * @return Amount of messages the connection can still buffer. */ static unsigned int get_connection_buffer (const struct CadetTConnection *tc) { int fwd; /* If connection is outgoing, is origin in the FWD direction and fwd is YES */ fwd = GCC_is_origin (tc->c, GNUNET_YES); return GCC_get_buffer (tc->c, fwd); } /** * Get the connection's allowance. * * @param tc Tunnel's connection handle. * * @return Amount of messages we have allowed the next peer to send us. */ static unsigned int get_connection_allowed (const struct CadetTConnection *tc) { int fwd; /* If connection is outgoing, is origin in the FWD direction and fwd is YES */ fwd = GCC_is_origin (tc->c, GNUNET_YES); return GCC_get_allowed (tc->c, fwd); } /** * Check that a ephemeral key message s well formed and correctly signed. * * @param t Tunnel on which the message came. * @param msg The ephemeral key message. * * @return GNUNET_OK if message is fine, GNUNET_SYSERR otherwise. */ int check_ephemeral (struct CadetTunnel *t, const struct GNUNET_CADET_KX_Ephemeral *msg) { /* Check message size */ if (ntohs (msg->header.size) != sizeof (struct GNUNET_CADET_KX_Ephemeral)) return GNUNET_SYSERR; /* Check signature size */ if (ntohl (msg->purpose.size) != ephemeral_purpose_size ()) return GNUNET_SYSERR; /* Check origin */ if (0 != memcmp (&msg->origin_identity, GCP_get_id (t->peer), sizeof (struct GNUNET_PeerIdentity))) return GNUNET_SYSERR; /* Check signature */ if (GNUNET_OK != GNUNET_CRYPTO_eddsa_verify (GNUNET_SIGNATURE_PURPOSE_CADET_KX, &msg->purpose, &msg->signature, &msg->origin_identity.public_key)) return GNUNET_SYSERR; return GNUNET_OK; } /** * Select the best key to use for encryption (send), based on KX status. * * Normally, return the current key. If there is a KX in progress and the old * key is fresh enough, return the old key. * * @param t Tunnel to choose the key from. * * @return The optimal key to encrypt/hmac outgoing traffic. */ static const struct GNUNET_CRYPTO_SymmetricSessionKey * select_key (const struct CadetTunnel *t) { const struct GNUNET_CRYPTO_SymmetricSessionKey *key; if (NULL != t->kx_ctx && GNUNET_SCHEDULER_NO_TASK == t->kx_ctx->finish_task) { struct GNUNET_TIME_Relative age; age = GNUNET_TIME_absolute_get_duration (t->kx_ctx->rekey_start_time); LOG (GNUNET_ERROR_TYPE_DEBUG, " key exchange in progress, started %s ago\n", GNUNET_STRINGS_relative_time_to_string (age, GNUNET_YES)); // FIXME make duration of old keys configurable if (age.rel_value_us < GNUNET_TIME_UNIT_MINUTES.rel_value_us) { LOG (GNUNET_ERROR_TYPE_DEBUG, " using old key\n"); key = &t->kx_ctx->e_key_old; } else { LOG (GNUNET_ERROR_TYPE_DEBUG, " using new key (old key too old)\n"); key = &t->e_key; } } else { LOG (GNUNET_ERROR_TYPE_DEBUG, " no KX: using current key\n"); key = &t->e_key; } return key; } /** * Calculate HMAC. * * @param plaintext Content to HMAC. * @param size Size of @c plaintext. * @param iv Initialization vector for the message. * @param key Key to use. * @param hmac[out] Destination to store the HMAC. */ static void t_hmac (const void *plaintext, size_t size, uint32_t iv, const struct GNUNET_CRYPTO_SymmetricSessionKey *key, struct GNUNET_CADET_Hash *hmac) { static const char ctx[] = "cadet authentication key"; struct GNUNET_CRYPTO_AuthKey auth_key; struct GNUNET_HashCode hash; #if DUMP_KEYS_TO_STDERR LOG (GNUNET_ERROR_TYPE_INFO, " HMAC with key %s\n", GNUNET_h2s ((struct GNUNET_HashCode *) key)); #endif GNUNET_CRYPTO_hmac_derive_key (&auth_key, key, &iv, sizeof (iv), key, sizeof (*key), ctx, sizeof (ctx), NULL); /* Two step: CADET_Hash is only 256 bits, HashCode is 512. */ GNUNET_CRYPTO_hmac (&auth_key, plaintext, size, &hash); memcpy (hmac, &hash, sizeof (*hmac)); } /** * Encrypt daforce_newest_keyta with the tunnel key. * * @param t Tunnel whose key to use. * @param dst Destination for the encrypted data. * @param src Source of the plaintext. Can overlap with @c dst. * @param size Size of the plaintext. * @param iv Initialization Vector to use. * @param force_newest_key Force the use of the newest key, otherwise * CADET will use the old key when allowed. * This can happen in the case when a KX is going on * and the old one hasn't expired. */ static int t_encrypt (struct CadetTunnel *t, void *dst, const void *src, size_t size, uint32_t iv, int force_newest_key) { struct GNUNET_CRYPTO_SymmetricInitializationVector siv; const struct GNUNET_CRYPTO_SymmetricSessionKey *key; size_t out_size; LOG (GNUNET_ERROR_TYPE_DEBUG, " t_encrypt start\n"); key = GNUNET_YES == force_newest_key ? &t->e_key : select_key (t); #if DUMP_KEYS_TO_STDERR LOG (GNUNET_ERROR_TYPE_INFO, " ENC with key %s\n", GNUNET_h2s ((struct GNUNET_HashCode *) key)); #endif GNUNET_CRYPTO_symmetric_derive_iv (&siv, key, &iv, sizeof (iv), NULL); LOG (GNUNET_ERROR_TYPE_DEBUG, " t_encrypt IV derived\n"); out_size = GNUNET_CRYPTO_symmetric_encrypt (src, size, key, &siv, dst); LOG (GNUNET_ERROR_TYPE_DEBUG, " t_encrypt end\n"); return out_size; } /** * Decrypt and verify data with the appropriate tunnel key. * * @param key Key to use. * @param dst Destination for the plaintext. * @param src Source of the encrypted data. Can overlap with @c dst. * @param size Size of the encrypted data. * @param iv Initialization Vector to use. * * @return Size of the decrypted data, -1 if an error was encountered. */ static int decrypt (const struct GNUNET_CRYPTO_SymmetricSessionKey *key, void *dst, const void *src, size_t size, uint32_t iv) { struct GNUNET_CRYPTO_SymmetricInitializationVector siv; size_t out_size; LOG (GNUNET_ERROR_TYPE_DEBUG, " decrypt start\n"); LOG (GNUNET_ERROR_TYPE_DEBUG, " decrypt iv\n"); GNUNET_CRYPTO_symmetric_derive_iv (&siv, key, &iv, sizeof (iv), NULL); LOG (GNUNET_ERROR_TYPE_DEBUG, " decrypt iv done\n"); out_size = GNUNET_CRYPTO_symmetric_decrypt (src, size, key, &siv, dst); LOG (GNUNET_ERROR_TYPE_DEBUG, " decrypt end\n"); return out_size; } /** * Decrypt and verify data with the most recent tunnel key. * * @param t Tunnel whose key to use. * @param dst Destination for the plaintext. * @param src Source of the encrypted data. Can overlap with @c dst. * @param size Size of the encrypted data. * @param iv Initialization Vector to use. * * @return Size of the decrypted data, -1 if an error was encountered. */ static int t_decrypt (struct CadetTunnel *t, void *dst, const void *src, size_t size, uint32_t iv) { size_t out_size; #if DUMP_KEYS_TO_STDERR LOG (GNUNET_ERROR_TYPE_DEBUG, " t_decrypt with %s\n", GNUNET_h2s ((struct GNUNET_HashCode *) &t->d_key)); #endif if (CADET_TUNNEL_KEY_UNINITIALIZED == t->estate) { GNUNET_STATISTICS_update (stats, "# non decryptable data", 1, GNUNET_NO); LOG (GNUNET_ERROR_TYPE_WARNING, "got data on %s without a valid key\n", GCT_2s (t)); GCT_debug (t, GNUNET_ERROR_TYPE_WARNING); return -1; } out_size = decrypt (&t->d_key, dst, src, size, iv); return out_size; } /** * Decrypt and verify data with the appropriate tunnel key and verify that the * data has not been altered since it was sent by the remote peer. * * @param t Tunnel whose key to use. * @param dst Destination for the plaintext. * @param src Source of the encrypted data. Can overlap with @c dst. * @param size Size of the encrypted data. * @param iv Initialization Vector to use. * @param msg_hmac HMAC of the message, cannot be NULL. * * @return Size of the decrypted data, -1 if an error was encountered. */ static int t_decrypt_and_validate (struct CadetTunnel *t, void *dst, const void *src, size_t size, uint32_t iv, const struct GNUNET_CADET_Hash *msg_hmac) { struct GNUNET_CRYPTO_SymmetricSessionKey *key; struct GNUNET_CADET_Hash hmac; int decrypted_size; /* Try primary (newest) key */ key = &t->d_key; decrypted_size = decrypt (key, dst, src, size, iv); t_hmac (src, size, iv, key, &hmac); if (0 == memcmp (msg_hmac, &hmac, sizeof (hmac))) return decrypted_size; /* If no key exchange is going on, we just failed */ if (NULL == t->kx_ctx) { GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "Failed checksum validation on tunnel %s with no KX\n", GCT_2s (t)); GNUNET_STATISTICS_update (stats, "# wrong HMAC", 1, GNUNET_NO); return -1; } /* Try secondary (from previous KX period) key */ key = &t->kx_ctx->d_key_old; decrypted_size = decrypt (key, dst, src, size, iv); t_hmac (src, size, iv, key, &hmac); if (0 == memcmp (msg_hmac, &hmac, sizeof (hmac))) return decrypted_size; GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "Failed checksum validation on tunnel %s with KX\n", GCT_2s (t)); GNUNET_STATISTICS_update (stats, "# wrong HMAC", 1, GNUNET_NO); return -1; } /** * Create key material by doing ECDH on the local and remote ephemeral keys. * * @param key_material Where to store the key material. * @param ephemeral_key Peer's public ephemeral key. */ void derive_key_material (struct GNUNET_HashCode *key_material, const struct GNUNET_CRYPTO_EcdhePublicKey *ephemeral_key) { if (GNUNET_OK != GNUNET_CRYPTO_ecc_ecdh (my_ephemeral_key, ephemeral_key, key_material)) { GNUNET_break (0); } } /** * Create a symmetic key from the identities of both ends and the key material * from ECDH. * * @param key Destination for the generated key. * @param sender ID of the peer that will encrypt with @c key. * @param receiver ID of the peer that will decrypt with @c key. * @param key_material Hash created with ECDH with the ephemeral keys. */ void derive_symmertic (struct GNUNET_CRYPTO_SymmetricSessionKey *key, const struct GNUNET_PeerIdentity *sender, const struct GNUNET_PeerIdentity *receiver, const struct GNUNET_HashCode *key_material) { const char salt[] = "CADET kx salt"; GNUNET_CRYPTO_kdf (key, sizeof (struct GNUNET_CRYPTO_SymmetricSessionKey), salt, sizeof (salt), key_material, sizeof (struct GNUNET_HashCode), sender, sizeof (struct GNUNET_PeerIdentity), receiver, sizeof (struct GNUNET_PeerIdentity), NULL); } /** * Create a new Key eXchange context for the tunnel. * * If the old keys were verified, keep them for old traffic. Create a new KX * timestamp and a new nonce. * * @param t Tunnel for which to create the KX ctx. */ static void create_kx_ctx (struct CadetTunnel *t) { LOG (GNUNET_ERROR_TYPE_INFO, " new kx ctx for %s\n", GCT_2s (t)); if (NULL != t->kx_ctx) { if (GNUNET_SCHEDULER_NO_TASK != t->kx_ctx->finish_task) { LOG (GNUNET_ERROR_TYPE_INFO, " resetting exisiting finish task\n"); GNUNET_SCHEDULER_cancel (t->kx_ctx->finish_task); t->kx_ctx->finish_task = GNUNET_SCHEDULER_NO_TASK; } } else { t->kx_ctx = GNUNET_new (struct CadetTunnelKXCtx); } t->kx_ctx->challenge = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_NONCE, UINT32_MAX); if (CADET_TUNNEL_KEY_OK == t->estate) { t->kx_ctx->d_key_old = t->d_key; t->kx_ctx->e_key_old = t->e_key; } t->kx_ctx->rekey_start_time = GNUNET_TIME_absolute_get (); } /** * @brief Finish the Key eXchange and destroy the old keys. * * @param cls Closure (Tunnel for which to finish the KX). * @param tc Task context. */ static void finish_kx (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) { struct CadetTunnel *t = cls; LOG (GNUNET_ERROR_TYPE_INFO, "finish KX for %s\n", GCT_2s (t)); if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN)) { LOG (GNUNET_ERROR_TYPE_INFO, " shutdown\n"); return; } GNUNET_free (t->kx_ctx); t->kx_ctx = NULL; } /** * Destroy a Key eXchange context for the tunnel. This function only schedules * the destruction, the freeing of the memory (and clearing of old key material) * happens after a delay! * * @param t Tunnel whose KX ctx to destroy. */ static void destroy_kx_ctx (struct CadetTunnel *t) { struct GNUNET_TIME_Relative delay; if (NULL == t->kx_ctx || GNUNET_SCHEDULER_NO_TASK != t->kx_ctx->finish_task) return; if (is_key_null (&t->kx_ctx->e_key_old)) { t->kx_ctx->finish_task = GNUNET_SCHEDULER_add_now (finish_kx, t); return; } delay = GNUNET_TIME_relative_divide (rekey_period, 4); delay = GNUNET_TIME_relative_min (delay, GNUNET_TIME_UNIT_MINUTES); t->kx_ctx->finish_task = GNUNET_SCHEDULER_add_delayed (delay, finish_kx, t); } /** * Derive the tunnel's keys using our own and the peer's ephemeral keys. * * @param t Tunnel for which to create the keys. */ static void create_keys (struct CadetTunnel *t) { struct GNUNET_HashCode km; derive_key_material (&km, &t->peers_ephemeral_key); derive_symmertic (&t->e_key, &my_full_id, GCP_get_id (t->peer), &km); derive_symmertic (&t->d_key, GCP_get_id (t->peer), &my_full_id, &km); #if DUMP_KEYS_TO_STDERR LOG (GNUNET_ERROR_TYPE_INFO, "ME: %s\n", GNUNET_h2s ((struct GNUNET_HashCode *) &kx_msg.ephemeral_key)); LOG (GNUNET_ERROR_TYPE_INFO, "PE: %s\n", GNUNET_h2s ((struct GNUNET_HashCode *) &t->peers_ephemeral_key)); LOG (GNUNET_ERROR_TYPE_INFO, "KM: %s\n", GNUNET_h2s (&km)); LOG (GNUNET_ERROR_TYPE_INFO, "EK: %s\n", GNUNET_h2s ((struct GNUNET_HashCode *) &t->e_key)); LOG (GNUNET_ERROR_TYPE_INFO, "DK: %s\n", GNUNET_h2s ((struct GNUNET_HashCode *) &t->d_key)); #endif } /** * Pick a connection on which send the next data message. * * @param t Tunnel on which to send the message. * * @return The connection on which to send the next message. */ static struct CadetConnection * tunnel_get_connection (struct CadetTunnel *t) { struct CadetTConnection *iter; struct CadetConnection *best; unsigned int qn; unsigned int lowest_q; LOG (GNUNET_ERROR_TYPE_DEBUG, "tunnel_get_connection %s\n", GCT_2s (t)); best = NULL; lowest_q = UINT_MAX; for (iter = t->connection_head; NULL != iter; iter = iter->next) { LOG (GNUNET_ERROR_TYPE_DEBUG, " connection %s: %u\n", GCC_2s (iter->c), GCC_get_state (iter->c)); if (CADET_CONNECTION_READY == GCC_get_state (iter->c)) { qn = GCC_get_qn (iter->c, GCC_is_origin (iter->c, GNUNET_YES)); LOG (GNUNET_ERROR_TYPE_DEBUG, " q_n %u, \n", qn); if (qn < lowest_q) { best = iter->c; lowest_q = qn; } } } LOG (GNUNET_ERROR_TYPE_DEBUG, " selected: connection %s\n", GCC_2s (best)); return best; } /** * Callback called when a queued message is sent. * * Calculates the average time and connection packet tracking. * * @param cls Closure (TunnelQueue handle). * @param c Connection this message was on. * @param q Connection queue handle (unused). * @param type Type of message sent. * @param fwd Was this a FWD going message? * @param size Size of the message. */ static void tun_message_sent (void *cls, struct CadetConnection *c, struct CadetConnectionQueue *q, uint16_t type, int fwd, size_t size) { struct CadetTunnelQueue *qt = cls; struct CadetTunnel *t; LOG (GNUNET_ERROR_TYPE_DEBUG, "tun_message_sent\n"); GNUNET_assert (NULL != qt->cont); t = NULL == c ? NULL : GCC_get_tunnel (c); qt->cont (qt->cont_cls, t, qt, type, size); GNUNET_free (qt); } static unsigned int count_queued_data (const struct CadetTunnel *t) { struct CadetTunnelDelayed *iter; unsigned int count; for (count = 0, iter = t->tq_head; iter != NULL; iter = iter->next) count++; return count; } /** * Delete a queued message: either was sent or the channel was destroyed * before the tunnel's key exchange had a chance to finish. * * @param tqd Delayed queue handle. */ static void unqueue_data (struct CadetTunnelDelayed *tqd) { GNUNET_CONTAINER_DLL_remove (tqd->t->tq_head, tqd->t->tq_tail, tqd); GNUNET_free (tqd); } /** * Cache a message to be sent once tunnel is online. * * @param t Tunnel to hold the message. * @param msg Message itself (copy will be made). */ static struct CadetTunnelDelayed * queue_data (struct CadetTunnel *t, const struct GNUNET_MessageHeader *msg) { struct CadetTunnelDelayed *tqd; uint16_t size = ntohs (msg->size); LOG (GNUNET_ERROR_TYPE_DEBUG, "queue data on Tunnel %s\n", GCT_2s (t)); if (GNUNET_YES == is_ready (t)) { GNUNET_break (0); return NULL; } tqd = GNUNET_malloc (sizeof (struct CadetTunnelDelayed) + size); tqd->t = t; memcpy (&tqd[1], msg, size); GNUNET_CONTAINER_DLL_insert_tail (t->tq_head, t->tq_tail, tqd); return tqd; } /** * Sends an already built message on a tunnel, encrypting it and * choosing the best connection. * * @param message Message to send. Function modifies it. * @param t Tunnel on which this message is transmitted. * @param c Connection to use (autoselect if NULL). * @param force Force the tunnel to take the message (buffer overfill). * @param cont Continuation to call once message is really sent. * @param cont_cls Closure for @c cont. * @param existing_q In case this a transmission of previously queued data, * this should be TunnelQueue given to the client. * Otherwise, NULL. * * @return Handle to cancel message. * NULL if @c cont is NULL or an error happens and message is dropped. */ static struct CadetTunnelQueue * send_prebuilt_message (const struct GNUNET_MessageHeader *message, struct CadetTunnel *t, struct CadetConnection *c, int force, GCT_sent cont, void *cont_cls, struct CadetTunnelQueue *existing_q) { struct CadetTunnelQueue *tq; struct GNUNET_CADET_Encrypted *msg; size_t size = ntohs (message->size); char cbuf[sizeof (struct GNUNET_CADET_Encrypted) + size]; uint32_t mid; uint32_t iv; uint16_t type; int fwd; LOG (GNUNET_ERROR_TYPE_DEBUG, "GMT Send on Tunnel %s\n", GCT_2s (t)); if (GNUNET_NO == is_ready (t)) { struct CadetTunnelDelayed *tqd; /* A non null existing_q indicates sending of queued data. * Should only happen after tunnel becomes ready. */ GNUNET_assert (NULL == existing_q); tqd = queue_data (t, message); if (NULL == cont) return NULL; tq = GNUNET_new (struct CadetTunnelQueue); tq->tqd = tqd; tqd->tq = tq; tq->cont = cont; tq->cont_cls = cont_cls; return tq; } GNUNET_assert (GNUNET_NO == GCT_is_loopback (t)); iv = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_NONCE, UINT32_MAX); msg = (struct GNUNET_CADET_Encrypted *) cbuf; msg->header.type = htons (GNUNET_MESSAGE_TYPE_CADET_ENCRYPTED); msg->iv = iv; GNUNET_assert (t_encrypt (t, &msg[1], message, size, iv, GNUNET_NO) == size); t_hmac (&msg[1], size, iv, select_key (t), &msg->hmac); msg->header.size = htons (sizeof (struct GNUNET_CADET_Encrypted) + size); if (NULL == c) c = tunnel_get_connection (t); if (NULL == c) { /* Why is tunnel 'ready'? Should have been queued! */ if (GNUNET_SCHEDULER_NO_TASK != t->destroy_task) { GNUNET_break (0); GCT_debug (t, GNUNET_ERROR_TYPE_WARNING); } return NULL; /* Drop... */ } mid = 0; type = ntohs (message->type); switch (type) { case GNUNET_MESSAGE_TYPE_CADET_DATA: case GNUNET_MESSAGE_TYPE_CADET_DATA_ACK: if (GNUNET_MESSAGE_TYPE_CADET_DATA == type) mid = ntohl (((struct GNUNET_CADET_Data *) message)->mid); else mid = ntohl (((struct GNUNET_CADET_DataACK *) message)->mid); /* Fall thru */ case GNUNET_MESSAGE_TYPE_CADET_KEEPALIVE: case GNUNET_MESSAGE_TYPE_CADET_CHANNEL_CREATE: case GNUNET_MESSAGE_TYPE_CADET_CHANNEL_DESTROY: case GNUNET_MESSAGE_TYPE_CADET_CHANNEL_ACK: case GNUNET_MESSAGE_TYPE_CADET_CHANNEL_NACK: msg->cid = *GCC_get_id (c); msg->ttl = htonl (default_ttl); break; default: GNUNET_break (0); LOG (GNUNET_ERROR_TYPE_ERROR, "type %s not valid\n", GC_m2s (type)); } LOG (GNUNET_ERROR_TYPE_DEBUG, "type %s\n", GC_m2s (type)); fwd = GCC_is_origin (c, GNUNET_YES); if (NULL == cont) { GNUNET_break (NULL == GCC_send_prebuilt_message (&msg->header, type, mid, c, fwd, force, NULL, NULL)); return NULL; } if (NULL == existing_q) { tq = GNUNET_new (struct CadetTunnelQueue); /* FIXME valgrind: leak*/ } else { tq = existing_q; tq->tqd = NULL; } tq->cq = GCC_send_prebuilt_message (&msg->header, type, mid, c, fwd, force, &tun_message_sent, tq); GNUNET_assert (NULL != tq->cq); tq->cont = cont; tq->cont_cls = cont_cls; return tq; } /** * Send all cached messages that we can, tunnel is online. * * @param t Tunnel that holds the messages. Cannot be loopback. */ static void send_queued_data (struct CadetTunnel *t) { struct CadetTunnelDelayed *tqd; struct CadetTunnelDelayed *next; unsigned int room; LOG (GNUNET_ERROR_TYPE_DEBUG, "GCT_send_queued_data on tunnel %s\n", GCT_2s (t)); if (GCT_is_loopback (t)) { GNUNET_break (0); return; } if (GNUNET_NO == is_ready (t)) { LOG (GNUNET_ERROR_TYPE_DEBUG, " not ready yet: %s/%s\n", estate2s (t->estate), cstate2s (t->cstate)); return; } room = GCT_get_connections_buffer (t); LOG (GNUNET_ERROR_TYPE_DEBUG, " buffer space: %u\n", room); LOG (GNUNET_ERROR_TYPE_DEBUG, " tq head: %p\n", t->tq_head); for (tqd = t->tq_head; NULL != tqd && room > 0; tqd = next) { LOG (GNUNET_ERROR_TYPE_DEBUG, " sending queued data\n"); next = tqd->next; room--; send_prebuilt_message ((struct GNUNET_MessageHeader *) &tqd[1], tqd->t, NULL, GNUNET_YES, NULL != tqd->tq ? tqd->tq->cont : NULL, NULL != tqd->tq ? tqd->tq->cont_cls : NULL, tqd->tq); unqueue_data (tqd); } LOG (GNUNET_ERROR_TYPE_DEBUG, "GCT_send_queued_data end\n", GCP_2s (t->peer)); } /** * Sends key exchange message on a tunnel, choosing the best connection. * Should not be called on loopback tunnels. * * @param t Tunnel on which this message is transmitted. * @param message Message to send. Function modifies it. */ static void send_kx (struct CadetTunnel *t, const struct GNUNET_MessageHeader *message) { struct CadetConnection *c; struct GNUNET_CADET_KX *msg; size_t size = ntohs (message->size); char cbuf[sizeof (struct GNUNET_CADET_KX) + size]; uint16_t type; int fwd; LOG (GNUNET_ERROR_TYPE_DEBUG, "GMT KX on Tunnel %s\n", GCT_2s (t)); /* Avoid loopback. */ if (GCT_is_loopback (t)) { LOG (GNUNET_ERROR_TYPE_DEBUG, " loopback!\n"); GNUNET_break (0); return; } type = ntohs (message->type); /* Even if tunnel is being destroyed, send anyway. * Could be a response to a rekey initiated by remote peer, * who is trying to create a new channel! */ /* Must have a connection, or be looking for one. */ if (NULL == t->connection_head) { if (CADET_TUNNEL_SEARCHING != t->cstate) { LOG (GNUNET_ERROR_TYPE_ERROR, "\n\n\n"); GNUNET_break (0); LOG (GNUNET_ERROR_TYPE_ERROR, "no connection, sending %s\n", GC_m2s (type)); GCT_debug (t, GNUNET_ERROR_TYPE_ERROR); GCP_debug (t->peer, GNUNET_ERROR_TYPE_ERROR); LOG (GNUNET_ERROR_TYPE_ERROR, "\n\n\n"); } return; } msg = (struct GNUNET_CADET_KX *) cbuf; msg->header.type = htons (GNUNET_MESSAGE_TYPE_CADET_KX); msg->header.size = htons (sizeof (struct GNUNET_CADET_KX) + size); c = tunnel_get_connection (t); if (NULL == c) { if (GNUNET_SCHEDULER_NO_TASK == t->destroy_task && CADET_TUNNEL_READY == t->cstate) { GNUNET_break (0); GCT_debug (t, GNUNET_ERROR_TYPE_ERROR); } return; } switch (type) { case GNUNET_MESSAGE_TYPE_CADET_KX_EPHEMERAL: case GNUNET_MESSAGE_TYPE_CADET_KX_PING: case GNUNET_MESSAGE_TYPE_CADET_KX_PONG: memcpy (&msg[1], message, size); break; default: LOG (GNUNET_ERROR_TYPE_DEBUG, "unkown type %s\n", GC_m2s (type)); GNUNET_break (0); } fwd = GCC_is_origin (t->connection_head->c, GNUNET_YES); /* TODO save handle and cancel in case of a unneeded retransmission */ GNUNET_assert (NULL == GCC_send_prebuilt_message (&msg->header, type, 0, c, fwd, GNUNET_YES, NULL, NULL)); } /** * Send the ephemeral key on a tunnel. * * @param t Tunnel on which to send the key. */ static void send_ephemeral (struct CadetTunnel *t) { LOG (GNUNET_ERROR_TYPE_INFO, "===> EPHM for %s\n", GCT_2s (t)); kx_msg.sender_status = htonl (t->estate); send_kx (t, &kx_msg.header); } /** * Send a ping message on a tunnel. * * @param t Tunnel on which to send the ping. */ static void send_ping (struct CadetTunnel *t) { struct GNUNET_CADET_KX_Ping msg; LOG (GNUNET_ERROR_TYPE_INFO, "===> PING for %s\n", GCT_2s (t)); msg.header.size = htons (sizeof (msg)); msg.header.type = htons (GNUNET_MESSAGE_TYPE_CADET_KX_PING); msg.iv = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_NONCE, UINT32_MAX); msg.target = *GCP_get_id (t->peer); msg.nonce = t->kx_ctx->challenge; LOG (GNUNET_ERROR_TYPE_DEBUG, " sending %u\n", msg.nonce); LOG (GNUNET_ERROR_TYPE_DEBUG, " towards %s\n", GNUNET_i2s (&msg.target)); t_encrypt (t, &msg.target, &msg.target, ping_encryption_size(), msg.iv, GNUNET_YES); LOG (GNUNET_ERROR_TYPE_DEBUG, " e sending %u\n", msg.nonce); LOG (GNUNET_ERROR_TYPE_DEBUG, " e towards %s\n", GNUNET_i2s (&msg.target)); send_kx (t, &msg.header); } /** * Send a pong message on a tunnel. *d_ * @param t Tunnel on which to send the pong. * @param challenge Value sent in the ping that we have to send back. */ static void send_pong (struct CadetTunnel *t, uint32_t challenge) { struct GNUNET_CADET_KX_Pong msg; LOG (GNUNET_ERROR_TYPE_INFO, "===> PONG for %s\n", GCT_2s (t)); msg.header.size = htons (sizeof (msg)); msg.header.type = htons (GNUNET_MESSAGE_TYPE_CADET_KX_PONG); msg.iv = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_NONCE, UINT32_MAX); msg.nonce = challenge; LOG (GNUNET_ERROR_TYPE_DEBUG, " sending %u\n", msg.nonce); t_encrypt (t, &msg.nonce, &msg.nonce, sizeof (msg.nonce), msg.iv, GNUNET_YES); LOG (GNUNET_ERROR_TYPE_DEBUG, " e sending %u\n", msg.nonce); send_kx (t, &msg.header); } /** * Initiate a rekey with the remote peer. * * @param cls Closure (tunnel). * @param tc TaskContext. */ static void rekey_tunnel (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) { struct CadetTunnel *t = cls; t->rekey_task = GNUNET_SCHEDULER_NO_TASK; LOG (GNUNET_ERROR_TYPE_INFO, "Re-key Tunnel %s\n", GCT_2s (t)); if (NULL != tc && 0 != (GNUNET_SCHEDULER_REASON_SHUTDOWN & tc->reason)) return; create_kx_ctx (t); if (NULL == t->kx_ctx) { create_keys (t); } else { struct GNUNET_TIME_Relative duration; duration = GNUNET_TIME_absolute_get_duration (t->kx_ctx->rekey_start_time); LOG (GNUNET_ERROR_TYPE_DEBUG, " kx started %s ago\n", GNUNET_STRINGS_relative_time_to_string (duration, GNUNET_YES)); // FIXME make duration of old keys configurable if (duration.rel_value_us >= GNUNET_TIME_UNIT_MINUTES.rel_value_us) { LOG (GNUNET_ERROR_TYPE_DEBUG, " deleting old keys\n"); memset (&t->kx_ctx->d_key_old, 0, sizeof (t->kx_ctx->d_key_old)); memset (&t->kx_ctx->e_key_old, 0, sizeof (t->kx_ctx->e_key_old)); } } send_ephemeral (t); switch (t->estate) { case CADET_TUNNEL_KEY_UNINITIALIZED: GCT_change_estate (t, CADET_TUNNEL_KEY_SENT); break; case CADET_TUNNEL_KEY_SENT: break; case CADET_TUNNEL_KEY_OK: GCT_change_estate (t, CADET_TUNNEL_KEY_REKEY); /* fall-thru */ case CADET_TUNNEL_KEY_PING: case CADET_TUNNEL_KEY_REKEY: send_ping (t); break; default: LOG (GNUNET_ERROR_TYPE_DEBUG, "Unexpected state %u\n", t->estate); } // FIXME exponential backoff struct GNUNET_TIME_Relative delay; delay = GNUNET_TIME_relative_divide (rekey_period, 16); delay = GNUNET_TIME_relative_min (delay, REKEY_WAIT); LOG (GNUNET_ERROR_TYPE_DEBUG, " next call in %s\n", GNUNET_STRINGS_relative_time_to_string (delay, GNUNET_YES)); t->rekey_task = GNUNET_SCHEDULER_add_delayed (delay, &rekey_tunnel, t); } /** * Our ephemeral key has changed, create new session key on all tunnels. * * Each tunnel will start the Key Exchange with a random delay between * 0 and number_of_tunnels*100 milliseconds, so there are 10 key exchanges * per second, on average. * * @param cls Closure (size of the hashmap). * @param key Current public key. * @param value Value in the hash map (tunnel). * * @return #GNUNET_YES, so we should continue to iterate, */ static int rekey_iterator (void *cls, const struct GNUNET_PeerIdentity *key, void *value) { struct CadetTunnel *t = value; struct GNUNET_TIME_Relative delay; long n = (long) cls; uint32_t r; if (GNUNET_SCHEDULER_NO_TASK != t->rekey_task) return GNUNET_YES; if (GNUNET_YES == GCT_is_loopback (t)) return GNUNET_YES; r = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK, (uint32_t) n * 100); delay = GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MILLISECONDS, r); t->rekey_task = GNUNET_SCHEDULER_add_delayed (delay, &rekey_tunnel, t); return GNUNET_YES; } /** * Create a new ephemeral key and key message, schedule next rekeying. * * @param cls Closure (unused). * @param tc TaskContext. */ static void rekey (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) { struct GNUNET_TIME_Absolute time; long n; rekey_task = GNUNET_SCHEDULER_NO_TASK; if (0 != (GNUNET_SCHEDULER_REASON_SHUTDOWN & tc->reason)) return; GNUNET_free_non_null (my_ephemeral_key); my_ephemeral_key = GNUNET_CRYPTO_ecdhe_key_create (); time = GNUNET_TIME_absolute_get (); kx_msg.creation_time = GNUNET_TIME_absolute_hton (time); time = GNUNET_TIME_absolute_add (time, rekey_period); time = GNUNET_TIME_absolute_add (time, GNUNET_TIME_UNIT_MINUTES); kx_msg.expiration_time = GNUNET_TIME_absolute_hton (time); GNUNET_CRYPTO_ecdhe_key_get_public (my_ephemeral_key, &kx_msg.ephemeral_key); LOG (GNUNET_ERROR_TYPE_INFO, "GLOBAL RE-KEY, NEW EPHM: %s\n", GNUNET_h2s ((struct GNUNET_HashCode *) &kx_msg.ephemeral_key)); GNUNET_assert (GNUNET_OK == GNUNET_CRYPTO_eddsa_sign (my_private_key, &kx_msg.purpose, &kx_msg.signature)); n = (long) GNUNET_CONTAINER_multipeermap_size (tunnels); GNUNET_CONTAINER_multipeermap_iterate (tunnels, &rekey_iterator, (void *) n); rekey_task = GNUNET_SCHEDULER_add_delayed (rekey_period, &rekey, NULL); } /** * Called only on shutdown, destroy every tunnel. * * @param cls Closure (unused). * @param key Current public key. * @param value Value in the hash map (tunnel). * * @return #GNUNET_YES, so we should continue to iterate, */ static int destroy_iterator (void *cls, const struct GNUNET_PeerIdentity *key, void *value) { struct CadetTunnel *t = value; LOG (GNUNET_ERROR_TYPE_DEBUG, "GCT_shutdown destroying tunnel at %p\n", t); GCT_destroy (t); return GNUNET_YES; } /** * Notify remote peer that we don't know a channel he is talking about, * probably CHANNEL_DESTROY was missed. * * @param t Tunnel on which to notify. * @param gid ID of the channel. */ static void send_channel_destroy (struct CadetTunnel *t, unsigned int gid) { struct GNUNET_CADET_ChannelManage msg; msg.header.type = htons (GNUNET_MESSAGE_TYPE_CADET_CHANNEL_DESTROY); msg.header.size = htons (sizeof (msg)); msg.chid = htonl (gid); LOG (GNUNET_ERROR_TYPE_DEBUG, "WARNING destroying unknown channel %u on tunnel %s\n", gid, GCT_2s (t)); send_prebuilt_message (&msg.header, t, NULL, GNUNET_YES, NULL, NULL, NULL); } /** * Demultiplex data per channel and call appropriate channel handler. * * @param t Tunnel on which the data came. * @param msg Data message. * @param fwd Is this message fwd? This only is meaningful in loopback channels. * #GNUNET_YES if message is FWD on the respective channel (loopback) * #GNUNET_NO if message is BCK on the respective channel (loopback) * #GNUNET_SYSERR if message on a one-ended channel (remote) */ static void handle_data (struct CadetTunnel *t, const struct GNUNET_CADET_Data *msg, int fwd) { struct CadetChannel *ch; size_t size; /* Check size */ size = ntohs (msg->header.size); if (size < sizeof (struct GNUNET_CADET_Data) + sizeof (struct GNUNET_MessageHeader)) { GNUNET_break (0); return; } LOG (GNUNET_ERROR_TYPE_DEBUG, " payload of type %s\n", GC_m2s (ntohs (msg[1].header.type))); /* Check channel */ ch = GCT_get_channel (t, ntohl (msg->chid)); if (NULL == ch) { GNUNET_STATISTICS_update (stats, "# data on unknown channel", 1, GNUNET_NO); LOG (GNUNET_ERROR_TYPE_DEBUG, "WARNING channel 0x%X unknown\n", ntohl (msg->chid)); send_channel_destroy (t, ntohl (msg->chid)); return; } GCCH_handle_data (ch, msg, fwd); } /** * Demultiplex data ACKs per channel and update appropriate channel buffer info. * * @param t Tunnel on which the DATA ACK came. * @param msg DATA ACK message. * @param fwd Is this message fwd? This only is meaningful in loopback channels. * #GNUNET_YES if message is FWD on the respective channel (loopback) * #GNUNET_NO if message is BCK on the respective channel (loopback) * #GNUNET_SYSERR if message on a one-ended channel (remote) */ static void handle_data_ack (struct CadetTunnel *t, const struct GNUNET_CADET_DataACK *msg, int fwd) { struct CadetChannel *ch; size_t size; /* Check size */ size = ntohs (msg->header.size); if (size != sizeof (struct GNUNET_CADET_DataACK)) { GNUNET_break (0); return; } /* Check channel */ ch = GCT_get_channel (t, ntohl (msg->chid)); if (NULL == ch) { GNUNET_STATISTICS_update (stats, "# data ack on unknown channel", 1, GNUNET_NO); LOG (GNUNET_ERROR_TYPE_DEBUG, "WARNING channel %u unknown\n", ntohl (msg->chid)); return; } GCCH_handle_data_ack (ch, msg, fwd); } /** * Handle channel create. * * @param t Tunnel on which the data came. * @param msg Data message. */ static void handle_ch_create (struct CadetTunnel *t, const struct GNUNET_CADET_ChannelCreate *msg) { struct CadetChannel *ch; size_t size; /* Check size */ size = ntohs (msg->header.size); if (size != sizeof (struct GNUNET_CADET_ChannelCreate)) { GNUNET_break (0); return; } /* Check channel */ ch = GCT_get_channel (t, ntohl (msg->chid)); if (NULL != ch && ! GCT_is_loopback (t)) { /* Probably a retransmission, safe to ignore */ LOG (GNUNET_ERROR_TYPE_DEBUG, " already exists...\n"); } ch = GCCH_handle_create (t, msg); if (NULL != ch) GCT_add_channel (t, ch); } /** * Handle channel NACK: check correctness and call channel handler for NACKs. * * @param t Tunnel on which the NACK came. * @param msg NACK message. */ static void handle_ch_nack (struct CadetTunnel *t, const struct GNUNET_CADET_ChannelManage *msg) { struct CadetChannel *ch; size_t size; /* Check size */ size = ntohs (msg->header.size); if (size != sizeof (struct GNUNET_CADET_ChannelManage)) { GNUNET_break (0); return; } /* Check channel */ ch = GCT_get_channel (t, ntohl (msg->chid)); if (NULL == ch) { GNUNET_STATISTICS_update (stats, "# channel NACK on unknown channel", 1, GNUNET_NO); LOG (GNUNET_ERROR_TYPE_DEBUG, "WARNING channel %u unknown\n", ntohl (msg->chid)); return; } GCCH_handle_nack (ch); } /** * Handle a CHANNEL ACK (SYNACK/ACK). * * @param t Tunnel on which the CHANNEL ACK came. * @param msg CHANNEL ACK message. * @param fwd Is this message fwd? This only is meaningful in loopback channels. * #GNUNET_YES if message is FWD on the respective channel (loopback) * #GNUNET_NO if message is BCK on the respective channel (loopback) * #GNUNET_SYSERR if message on a one-ended channel (remote) */ static void handle_ch_ack (struct CadetTunnel *t, const struct GNUNET_CADET_ChannelManage *msg, int fwd) { struct CadetChannel *ch; size_t size; /* Check size */ size = ntohs (msg->header.size); if (size != sizeof (struct GNUNET_CADET_ChannelManage)) { GNUNET_break (0); return; } /* Check channel */ ch = GCT_get_channel (t, ntohl (msg->chid)); if (NULL == ch) { GNUNET_STATISTICS_update (stats, "# channel ack on unknown channel", 1, GNUNET_NO); LOG (GNUNET_ERROR_TYPE_DEBUG, "WARNING channel %u unknown\n", ntohl (msg->chid)); return; } GCCH_handle_ack (ch, msg, fwd); } /** * Handle a channel destruction message. * * @param t Tunnel on which the message came. * @param msg Channel destroy message. * @param fwd Is this message fwd? This only is meaningful in loopback channels. * #GNUNET_YES if message is FWD on the respective channel (loopback) * #GNUNET_NO if message is BCK on the respective channel (loopback) * #GNUNET_SYSERR if message on a one-ended channel (remote) */ static void handle_ch_destroy (struct CadetTunnel *t, const struct GNUNET_CADET_ChannelManage *msg, int fwd) { struct CadetChannel *ch; size_t size; /* Check size */ size = ntohs (msg->header.size); if (size != sizeof (struct GNUNET_CADET_ChannelManage)) { GNUNET_break (0); return; } /* Check channel */ ch = GCT_get_channel (t, ntohl (msg->chid)); if (NULL == ch) { /* Probably a retransmission, safe to ignore */ return; } GCCH_handle_destroy (ch, msg, fwd); } /** * The peer's ephemeral key has changed: update the symmetrical keys. * * @param t Tunnel this message came on. * @param msg Key eXchange message. */ static void handle_ephemeral (struct CadetTunnel *t, const struct GNUNET_CADET_KX_Ephemeral *msg) { LOG (GNUNET_ERROR_TYPE_INFO, "<=== EPHM for %s\n", GCT_2s (t)); if (GNUNET_OK != check_ephemeral (t, msg)) { GNUNET_break_op (0); return; } /** * If the key is different from what we know, derive the new E/D keys. * Else destroy the rekey ctx (duplicate EPHM after successful KX). */ if (0 != memcmp (&t->peers_ephemeral_key, &msg->ephemeral_key, sizeof (msg->ephemeral_key))) { #if DUMP_KEYS_TO_STDERR LOG (GNUNET_ERROR_TYPE_INFO, "OLD: %s\n", GNUNET_h2s ((struct GNUNET_HashCode *) &t->peers_ephemeral_key)); LOG (GNUNET_ERROR_TYPE_INFO, "NEW: %s\n", GNUNET_h2s ((struct GNUNET_HashCode *) &msg->ephemeral_key)); #endif t->peers_ephemeral_key = msg->ephemeral_key; create_kx_ctx (t); create_keys (t); if (CADET_TUNNEL_KEY_OK == t->estate) { GCT_change_estate (t, CADET_TUNNEL_KEY_REKEY); } if (GNUNET_SCHEDULER_NO_TASK != t->rekey_task) GNUNET_SCHEDULER_cancel (t->rekey_task); t->rekey_task = GNUNET_SCHEDULER_add_now (rekey_tunnel, t); } if (CADET_TUNNEL_KEY_SENT == t->estate) { LOG (GNUNET_ERROR_TYPE_DEBUG, " our key was sent, sending ping\n"); send_ping (t); GCT_change_estate (t, CADET_TUNNEL_KEY_PING); } } /** * Peer wants to check our symmetrical keys by sending an encrypted challenge. * Answer with by retransmitting the challenge with the "opposite" key. * * @param t Tunnel this message came on. * @param msg Key eXchange Ping message. */ static void handle_ping (struct CadetTunnel *t, const struct GNUNET_CADET_KX_Ping *msg) { struct GNUNET_CADET_KX_Ping res; if (ntohs (msg->header.size) != sizeof (res)) { GNUNET_break_op (0); return; } LOG (GNUNET_ERROR_TYPE_INFO, "<=== PING for %s\n", GCT_2s (t)); t_decrypt (t, &res.target, &msg->target, ping_encryption_size (), msg->iv); if (0 != memcmp (&my_full_id, &res.target, sizeof (my_full_id))) { /* probably peer hasn't got our new EPHM yet and derived the wrong keys */ GNUNET_STATISTICS_update (stats, "# malformed PINGs", 1, GNUNET_NO); LOG (GNUNET_ERROR_TYPE_INFO, " malformed PING on %s\n", GCT_2s (t)); LOG (GNUNET_ERROR_TYPE_DEBUG, " e got %u\n", msg->nonce); LOG (GNUNET_ERROR_TYPE_DEBUG, " e towards %s\n", GNUNET_i2s (&msg->target)); LOG (GNUNET_ERROR_TYPE_DEBUG, " got %u\n", res.nonce); LOG (GNUNET_ERROR_TYPE_DEBUG, " towards %s\n", GNUNET_i2s (&res.target)); create_kx_ctx (t); send_ephemeral (t); send_ping (t); return; } send_pong (t, res.nonce); } /** * Peer has answer to our challenge. * If answer is successful, consider the key exchange finished and clean * up all related state. * * @param t Tunnel this message came on. * @param msg Key eXchange Pong message. */ static void handle_pong (struct CadetTunnel *t, const struct GNUNET_CADET_KX_Pong *msg) { uint32_t challenge; LOG (GNUNET_ERROR_TYPE_INFO, "<=== PONG for %s\n", GCT_2s (t)); if (GNUNET_SCHEDULER_NO_TASK == t->rekey_task) { GNUNET_STATISTICS_update (stats, "# duplicate PONG messages", 1, GNUNET_NO); return; } t_decrypt (t, &challenge, &msg->nonce, sizeof (uint32_t), msg->iv); if (challenge != t->kx_ctx->challenge) { LOG (GNUNET_ERROR_TYPE_WARNING, "Wrong PONG challenge on %s\n", GCT_2s (t)); LOG (GNUNET_ERROR_TYPE_DEBUG, "PONG: %u (e: %u). Expected: %u.\n", challenge, msg->nonce, t->kx_ctx->challenge); send_ephemeral (t); send_ping (t); return; } GNUNET_SCHEDULER_cancel (t->rekey_task); t->rekey_task = GNUNET_SCHEDULER_NO_TASK; /* Don't free the old keys right away, but after a delay. * Rationale: the KX could have happened over a very fast connection, * with payload traffic still signed with the old key stuck in a slower * connection. * Don't keep the keys longer than 1/4 the rekey period, and no longer than * one minute. */ destroy_kx_ctx (t); GCT_change_estate (t, CADET_TUNNEL_KEY_OK); } /** * Demultiplex by message type and call appropriate handler for a message * towards a channel of a local tunnel. * * @param t Tunnel this message came on. * @param msgh Message header. * @param fwd Is this message fwd? This only is meaningful in loopback channels. * #GNUNET_YES if message is FWD on the respective channel (loopback) * #GNUNET_NO if message is BCK on the respective channel (loopback) * #GNUNET_SYSERR if message on a one-ended channel (remote) */ static void handle_decrypted (struct CadetTunnel *t, const struct GNUNET_MessageHeader *msgh, int fwd) { uint16_t type; type = ntohs (msgh->type); LOG (GNUNET_ERROR_TYPE_INFO, "<=== %s on %s\n", GC_m2s (type), GCT_2s (t)); switch (type) { case GNUNET_MESSAGE_TYPE_CADET_KEEPALIVE: /* Do nothing, connection aleady got updated. */ GNUNET_STATISTICS_update (stats, "# keepalives received", 1, GNUNET_NO); break; case GNUNET_MESSAGE_TYPE_CADET_DATA: /* Don't send hop ACK, wait for client to ACK */ handle_data (t, (struct GNUNET_CADET_Data *) msgh, fwd); break; case GNUNET_MESSAGE_TYPE_CADET_DATA_ACK: handle_data_ack (t, (struct GNUNET_CADET_DataACK *) msgh, fwd); break; case GNUNET_MESSAGE_TYPE_CADET_CHANNEL_CREATE: handle_ch_create (t, (struct GNUNET_CADET_ChannelCreate *) msgh); break; case GNUNET_MESSAGE_TYPE_CADET_CHANNEL_NACK: handle_ch_nack (t, (struct GNUNET_CADET_ChannelManage *) msgh); break; case GNUNET_MESSAGE_TYPE_CADET_CHANNEL_ACK: handle_ch_ack (t, (struct GNUNET_CADET_ChannelManage *) msgh, fwd); break; case GNUNET_MESSAGE_TYPE_CADET_CHANNEL_DESTROY: handle_ch_destroy (t, (struct GNUNET_CADET_ChannelManage *) msgh, fwd); break; default: GNUNET_break_op (0); LOG (GNUNET_ERROR_TYPE_WARNING, "end-to-end message not known (%u)\n", ntohs (msgh->type)); GCT_debug (t, GNUNET_ERROR_TYPE_WARNING); } } /******************************************************************************/ /******************************** API ***********************************/ /******************************************************************************/ /** * Decrypt and demultiplex by message type. Call appropriate handler * for every message. * * @param t Tunnel this message came on. * @param msg Encrypted message. */ void GCT_handle_encrypted (struct CadetTunnel *t, const struct GNUNET_CADET_Encrypted *msg) { size_t size = ntohs (msg->header.size); size_t payload_size = size - sizeof (struct GNUNET_CADET_Encrypted); int decrypted_size; char cbuf [payload_size]; struct GNUNET_MessageHeader *msgh; unsigned int off; decrypted_size = t_decrypt_and_validate (t, cbuf, &msg[1], payload_size, msg->iv, &msg->hmac); if (-1 == decrypted_size) { GNUNET_break_op (0); return; } off = 0; while (off < decrypted_size) { uint16_t msize; msgh = (struct GNUNET_MessageHeader *) &cbuf[off]; msize = ntohs (msgh->size); if (msize < sizeof (struct GNUNET_MessageHeader)) { GNUNET_break_op (0); return; } handle_decrypted (t, msgh, GNUNET_SYSERR); off += msize; } } /** * Demultiplex an encapsulated KX message by message type. * * @param t Tunnel on which the message came. * @param message Payload of KX message. */ void GCT_handle_kx (struct CadetTunnel *t, const struct GNUNET_MessageHeader *message) { uint16_t type; type = ntohs (message->type); LOG (GNUNET_ERROR_TYPE_DEBUG, "kx message received\n", type); switch (type) { case GNUNET_MESSAGE_TYPE_CADET_KX_EPHEMERAL: handle_ephemeral (t, (struct GNUNET_CADET_KX_Ephemeral *) message); break; case GNUNET_MESSAGE_TYPE_CADET_KX_PING: handle_ping (t, (struct GNUNET_CADET_KX_Ping *) message); break; case GNUNET_MESSAGE_TYPE_CADET_KX_PONG: handle_pong (t, (struct GNUNET_CADET_KX_Pong *) message); break; default: GNUNET_break_op (0); LOG (GNUNET_ERROR_TYPE_DEBUG, "kx message not known (%u)\n", type); } } /** * Initialize the tunnel subsystem. * * @param c Configuration handle. * @param key ECC private key, to derive all other keys and do crypto. */ void GCT_init (const struct GNUNET_CONFIGURATION_Handle *c, const struct GNUNET_CRYPTO_EddsaPrivateKey *key) { int expected_overhead; LOG (GNUNET_ERROR_TYPE_DEBUG, "init\n"); expected_overhead = sizeof (struct GNUNET_CADET_Encrypted) + sizeof (struct GNUNET_CADET_Data); GNUNET_assert (GNUNET_CONSTANTS_CADET_P2P_OVERHEAD == expected_overhead); if (GNUNET_OK != GNUNET_CONFIGURATION_get_value_number (c, "CADET", "DEFAULT_TTL", &default_ttl)) { GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_WARNING, "CADET", "DEFAULT_TTL", "USING DEFAULT"); default_ttl = 64; } if (GNUNET_OK != GNUNET_CONFIGURATION_get_value_time (c, "CADET", "REKEY_PERIOD", &rekey_period)) { rekey_period = GNUNET_TIME_UNIT_DAYS; } my_private_key = key; kx_msg.header.size = htons (sizeof (kx_msg)); kx_msg.header.type = htons (GNUNET_MESSAGE_TYPE_CADET_KX_EPHEMERAL); kx_msg.purpose.purpose = htonl (GNUNET_SIGNATURE_PURPOSE_CADET_KX); kx_msg.purpose.size = htonl (ephemeral_purpose_size ()); kx_msg.origin_identity = my_full_id; rekey_task = GNUNET_SCHEDULER_add_now (&rekey, NULL); tunnels = GNUNET_CONTAINER_multipeermap_create (128, GNUNET_YES); } /** * Shut down the tunnel subsystem. */ void GCT_shutdown (void) { if (GNUNET_SCHEDULER_NO_TASK != rekey_task) { GNUNET_SCHEDULER_cancel (rekey_task); rekey_task = GNUNET_SCHEDULER_NO_TASK; } GNUNET_CONTAINER_multipeermap_iterate (tunnels, &destroy_iterator, NULL); GNUNET_CONTAINER_multipeermap_destroy (tunnels); } /** * Create a tunnel. * * @param destination Peer this tunnel is towards. */ struct CadetTunnel * GCT_new (struct CadetPeer *destination) { struct CadetTunnel *t; t = GNUNET_new (struct CadetTunnel); t->next_chid = 0; t->peer = destination; if (GNUNET_OK != GNUNET_CONTAINER_multipeermap_put (tunnels, GCP_get_id (destination), t, GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_FAST)) { GNUNET_break (0); GNUNET_free (t); return NULL; } return t; } /** * Change the tunnel's connection state. * * @param t Tunnel whose connection state to change. * @param cstate New connection state. */ void GCT_change_cstate (struct CadetTunnel* t, enum CadetTunnelCState cstate) { if (NULL == t) return; LOG (GNUNET_ERROR_TYPE_DEBUG, "Tunnel %s cstate %s => %s\n", GCP_2s (t->peer), cstate2s (t->cstate), cstate2s (cstate)); if (myid != GCP_get_short_id (t->peer) && CADET_TUNNEL_READY != t->cstate && CADET_TUNNEL_READY == cstate) { t->cstate = cstate; if (CADET_TUNNEL_KEY_OK == t->estate) { LOG (GNUNET_ERROR_TYPE_DEBUG, " cstate triggered send queued data\n"); send_queued_data (t); } else if (CADET_TUNNEL_KEY_UNINITIALIZED == t->estate) { LOG (GNUNET_ERROR_TYPE_DEBUG, " cstate triggered rekey\n"); if (GNUNET_SCHEDULER_NO_TASK != t->rekey_task) GNUNET_SCHEDULER_cancel (t->rekey_task); rekey_tunnel (t, NULL); } } t->cstate = cstate; if (CADET_TUNNEL_READY == cstate && CONNECTIONS_PER_TUNNEL <= GCT_count_connections (t)) { LOG (GNUNET_ERROR_TYPE_DEBUG, " cstate triggered stop dht\n"); GCP_stop_search (t->peer); } } /** * Change the tunnel encryption state. * * @param t Tunnel whose encryption state to change, or NULL. * @param state New encryption state. */ void GCT_change_estate (struct CadetTunnel* t, enum CadetTunnelEState state) { if (NULL == t) return; LOG (GNUNET_ERROR_TYPE_DEBUG, "Tunnel %s estate was %s\n", GCP_2s (t->peer), estate2s (t->estate)); LOG (GNUNET_ERROR_TYPE_DEBUG, "Tunnel %s estate is now %s\n", GCP_2s (t->peer), estate2s (state)); /* Send queued data if enc state changes to OK */ if (myid != GCP_get_short_id (t->peer) && CADET_TUNNEL_KEY_OK != t->estate && CADET_TUNNEL_KEY_OK == state) { send_queued_data (t); } t->estate = state; } /** * @brief Check if tunnel has too many connections, and remove one if necessary. * * Currently this means the newest connection, unless it is a direct one. * Implemented as a task to avoid freeing a connection that is in the middle * of being created/processed. * * @param cls Closure (Tunnel to check). * @param tc Task context. */ static void trim_connections (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) { struct CadetTunnel *t = cls; t->trim_connections_task = GNUNET_SCHEDULER_NO_TASK; if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN)) return; if (GCT_count_connections (t) > 2 * CONNECTIONS_PER_TUNNEL) { struct CadetTConnection *iter; struct CadetTConnection *c; for (c = iter = t->connection_head; NULL != iter; iter = iter->next) { if ((NULL == c || iter->created.abs_value_us > c->created.abs_value_us) && GNUNET_NO == GCC_is_direct (iter->c)) { c = iter; } } if (NULL != c) { LOG (GNUNET_ERROR_TYPE_DEBUG, "Too many connections on tunnel %s\n", GCT_2s (t)); LOG (GNUNET_ERROR_TYPE_DEBUG, "Destroying connection %s\n", GCC_2s (c->c)); GCC_destroy (c->c); } else { GNUNET_break (0); } } } /** * Add a connection to a tunnel. * * @param t Tunnel. * @param c Connection. */ void GCT_add_connection (struct CadetTunnel *t, struct CadetConnection *c) { struct CadetTConnection *aux; GNUNET_assert (NULL != c); LOG (GNUNET_ERROR_TYPE_DEBUG, "add connection %s\n", GCC_2s (c)); LOG (GNUNET_ERROR_TYPE_DEBUG, " to tunnel %s\n", GCT_2s (t)); for (aux = t->connection_head; aux != NULL; aux = aux->next) if (aux->c == c) return; aux = GNUNET_new (struct CadetTConnection); aux->c = c; aux->created = GNUNET_TIME_absolute_get (); GNUNET_CONTAINER_DLL_insert (t->connection_head, t->connection_tail, aux); if (CADET_TUNNEL_SEARCHING == t->cstate) GCT_change_estate (t, CADET_TUNNEL_WAITING); if (GNUNET_SCHEDULER_NO_TASK != t->trim_connections_task) t->trim_connections_task = GNUNET_SCHEDULER_add_now (&trim_connections, t); } /** * Remove a connection from a tunnel. * * @param t Tunnel. * @param c Connection. */ void GCT_remove_connection (struct CadetTunnel *t, struct CadetConnection *c) { struct CadetTConnection *aux; struct CadetTConnection *next; unsigned int conns; LOG (GNUNET_ERROR_TYPE_DEBUG, "Removing connection %s from tunnel %s\n", GCC_2s (c), GCT_2s (t)); for (aux = t->connection_head; aux != NULL; aux = next) { next = aux->next; if (aux->c == c) { GNUNET_CONTAINER_DLL_remove (t->connection_head, t->connection_tail, aux); GNUNET_free (aux); } } conns = GCT_count_connections (t); if (0 == conns && GNUNET_SCHEDULER_NO_TASK == t->destroy_task && CADET_TUNNEL_SHUTDOWN != t->cstate && GNUNET_NO == shutting_down) { if (0 == GCT_count_any_connections (t)) GCT_change_cstate (t, CADET_TUNNEL_SEARCHING); else GCT_change_cstate (t, CADET_TUNNEL_WAITING); } /* Start new connections if needed */ if (CONNECTIONS_PER_TUNNEL > conns && GNUNET_SCHEDULER_NO_TASK == t->destroy_task && CADET_TUNNEL_SHUTDOWN != t->cstate && GNUNET_NO == shutting_down) { LOG (GNUNET_ERROR_TYPE_DEBUG, " too few connections, getting new ones\n"); GCP_connect (t->peer); /* Will change cstate to WAITING when possible */ return; } /* If not marked as ready, no change is needed */ if (CADET_TUNNEL_READY != t->cstate) return; /* Check if any connection is ready to maintain cstate */ for (aux = t->connection_head; aux != NULL; aux = aux->next) if (CADET_CONNECTION_READY == GCC_get_state (aux->c)) return; } /** * Add a channel to a tunnel. * * @param t Tunnel. * @param ch Channel. */ void GCT_add_channel (struct CadetTunnel *t, struct CadetChannel *ch) { struct CadetTChannel *aux; GNUNET_assert (NULL != ch); LOG (GNUNET_ERROR_TYPE_DEBUG, "Adding channel %p to tunnel %p\n", ch, t); for (aux = t->channel_head; aux != NULL; aux = aux->next) { LOG (GNUNET_ERROR_TYPE_DEBUG, " already there %p\n", aux->ch); if (aux->ch == ch) return; } aux = GNUNET_new (struct CadetTChannel); aux->ch = ch; LOG (GNUNET_ERROR_TYPE_DEBUG, " adding %p to %p\n", aux, t->channel_head); GNUNET_CONTAINER_DLL_insert_tail (t->channel_head, t->channel_tail, aux); if (GNUNET_SCHEDULER_NO_TASK != t->destroy_task) { GNUNET_SCHEDULER_cancel (t->destroy_task); t->destroy_task = GNUNET_SCHEDULER_NO_TASK; LOG (GNUNET_ERROR_TYPE_DEBUG, " undo destroy!\n"); } } /** * Remove a channel from a tunnel. * * @param t Tunnel. * @param ch Channel. */ void GCT_remove_channel (struct CadetTunnel *t, struct CadetChannel *ch) { struct CadetTChannel *aux; LOG (GNUNET_ERROR_TYPE_DEBUG, "Removing channel %p from tunnel %p\n", ch, t); for (aux = t->channel_head; aux != NULL; aux = aux->next) { if (aux->ch == ch) { LOG (GNUNET_ERROR_TYPE_DEBUG, " found! %s\n", GCCH_2s (ch)); GNUNET_CONTAINER_DLL_remove (t->channel_head, t->channel_tail, aux); GNUNET_free (aux); return; } } } /** * Search for a channel by global ID. * * @param t Tunnel containing the channel. * @param chid Public channel number. * * @return channel handler, NULL if doesn't exist */ struct CadetChannel * GCT_get_channel (struct CadetTunnel *t, CADET_ChannelNumber chid) { struct CadetTChannel *iter; if (NULL == t) return NULL; for (iter = t->channel_head; NULL != iter; iter = iter->next) { if (GCCH_get_id (iter->ch) == chid) break; } return NULL == iter ? NULL : iter->ch; } /** * @brief Destroy a tunnel and free all resources. * * Should only be called a while after the tunnel has been marked as destroyed, * in case there is a new channel added to the same peer shortly after marking * the tunnel. This way we avoid a new public key handshake. * * @param cls Closure (tunnel to destroy). * @param tc Task context. */ static void delayed_destroy (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) { struct CadetTunnel *t = cls; struct CadetTConnection *iter; LOG (GNUNET_ERROR_TYPE_DEBUG, "delayed destroying tunnel %p\n", t); if (0 != (GNUNET_SCHEDULER_REASON_SHUTDOWN & tc->reason)) { LOG (GNUNET_ERROR_TYPE_WARNING, "Not destroying tunnel, due to shutdown. " "Tunnel at %p should have been freed by GCT_shutdown\n", t); return; } t->destroy_task = GNUNET_SCHEDULER_NO_TASK; t->cstate = CADET_TUNNEL_SHUTDOWN; for (iter = t->connection_head; NULL != iter; iter = iter->next) { GCC_send_destroy (iter->c); } GCT_destroy (t); } /** * Tunnel is empty: destroy it. * * Notifies all connections about the destruction. * * @param t Tunnel to destroy. */ void GCT_destroy_empty (struct CadetTunnel *t) { if (GNUNET_YES == shutting_down) return; /* Will be destroyed immediately anyway */ if (GNUNET_SCHEDULER_NO_TASK != t->destroy_task) { LOG (GNUNET_ERROR_TYPE_WARNING, "Tunnel %s is already scheduled for destruction. Tunnel debug dump:\n", GCT_2s (t)); GCT_debug (t, GNUNET_ERROR_TYPE_WARNING); GNUNET_break (0); /* should never happen, tunnel can only become empty once, and the * task identifier should be NO_TASK (cleaned when the tunnel was created * or became un-empty) */ return; } LOG (GNUNET_ERROR_TYPE_DEBUG, "Tunnel %s empty: destroying scheduled\n", GCT_2s (t)); // FIXME make delay a config option t->destroy_task = GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_MINUTES, &delayed_destroy, t); LOG (GNUNET_ERROR_TYPE_DEBUG, "Scheduled destroy of %p as %llX\n", t, t->destroy_task); } /** * Destroy tunnel if empty (no more channels). * * @param t Tunnel to destroy if empty. */ void GCT_destroy_if_empty (struct CadetTunnel *t) { LOG (GNUNET_ERROR_TYPE_DEBUG, "Tunnel %s destroy if empty\n", GCT_2s (t)); if (1 < GCT_count_channels (t)) return; GCT_destroy_empty (t); } /** * Destroy the tunnel. * * This function does not generate any warning traffic to clients or peers. * * Tasks: * Cancel messages belonging to this tunnel queued to neighbors. * Free any allocated resources linked to the tunnel. * * @param t The tunnel to destroy. */ void GCT_destroy (struct CadetTunnel *t) { struct CadetTConnection *iter_c; struct CadetTConnection *next_c; struct CadetTChannel *iter_ch; struct CadetTChannel *next_ch; if (NULL == t) return; LOG (GNUNET_ERROR_TYPE_DEBUG, "destroying tunnel %s\n", GCP_2s (t->peer)); GNUNET_break (GNUNET_YES == GNUNET_CONTAINER_multipeermap_remove (tunnels, GCP_get_id (t->peer), t)); for (iter_c = t->connection_head; NULL != iter_c; iter_c = next_c) { next_c = iter_c->next; GCC_destroy (iter_c->c); } for (iter_ch = t->channel_head; NULL != iter_ch; iter_ch = next_ch) { next_ch = iter_ch->next; GCCH_destroy (iter_ch->ch); /* Should only happen on shutdown, but it's ok. */ } if (GNUNET_SCHEDULER_NO_TASK != t->destroy_task) { LOG (GNUNET_ERROR_TYPE_DEBUG, "cancelling dest: %llX\n", t->destroy_task); GNUNET_SCHEDULER_cancel (t->destroy_task); t->destroy_task = GNUNET_SCHEDULER_NO_TASK; } if (GNUNET_SCHEDULER_NO_TASK != t->trim_connections_task) { LOG (GNUNET_ERROR_TYPE_DEBUG, "cancelling trim: %llX\n", t->trim_connections_task); GNUNET_SCHEDULER_cancel (t->trim_connections_task); t->trim_connections_task = GNUNET_SCHEDULER_NO_TASK; } GNUNET_STATISTICS_update (stats, "# tunnels", -1, GNUNET_NO); GCP_set_tunnel (t->peer, NULL); if (GNUNET_SCHEDULER_NO_TASK != t->rekey_task) { GNUNET_SCHEDULER_cancel (t->rekey_task); t->rekey_task = GNUNET_SCHEDULER_NO_TASK; } if (NULL != t->kx_ctx) { if (GNUNET_SCHEDULER_NO_TASK != t->kx_ctx->finish_task) GNUNET_SCHEDULER_cancel (t->kx_ctx->finish_task); GNUNET_free (t->kx_ctx); } GNUNET_free (t); } /** * @brief Use the given path for the tunnel. * Update the next and prev hops (and RCs). * (Re)start the path refresh in case the tunnel is locally owned. * * @param t Tunnel to update. * @param p Path to use. * * @return Connection created. */ struct CadetConnection * GCT_use_path (struct CadetTunnel *t, struct CadetPeerPath *p) { struct CadetConnection *c; struct GNUNET_CADET_Hash cid; unsigned int own_pos; if (NULL == t || NULL == p) { GNUNET_break (0); return NULL; } if (CADET_TUNNEL_SHUTDOWN == t->cstate) { GNUNET_break (0); return NULL; } for (own_pos = 0; own_pos < p->length; own_pos++) { if (p->peers[own_pos] == myid) break; } if (own_pos >= p->length) { GNUNET_break_op (0); return NULL; } GNUNET_CRYPTO_random_block (GNUNET_CRYPTO_QUALITY_NONCE, &cid, sizeof (cid)); c = GCC_new (&cid, t, p, own_pos); if (NULL == c) { /* Path was flawed */ return NULL; } GCT_add_connection (t, c); return c; } /** * Count all created connections of a tunnel. Not necessarily ready connections! * * @param t Tunnel on which to count. * * @return Number of connections created, either being established or ready. */ unsigned int GCT_count_any_connections (struct CadetTunnel *t) { struct CadetTConnection *iter; unsigned int count; if (NULL == t) return 0; for (count = 0, iter = t->connection_head; NULL != iter; iter = iter->next) count++; return count; } /** * Count established (ready) connections of a tunnel. * * @param t Tunnel on which to count. * * @return Number of connections. */ unsigned int GCT_count_connections (struct CadetTunnel *t) { struct CadetTConnection *iter; unsigned int count; if (NULL == t) return 0; for (count = 0, iter = t->connection_head; NULL != iter; iter = iter->next) if (CADET_CONNECTION_DESTROYED != GCC_get_state (iter->c)) count++; return count; } /** * Count channels of a tunnel. * * @param t Tunnel on which to count. * * @return Number of channels. */ unsigned int GCT_count_channels (struct CadetTunnel *t) { struct CadetTChannel *iter; unsigned int count; for (count = 0, iter = t->channel_head; NULL != iter; iter = iter->next, count++) /* skip */; return count; } /** * Get the connectivity state of a tunnel. * * @param t Tunnel. * * @return Tunnel's connectivity state. */ enum CadetTunnelCState GCT_get_cstate (struct CadetTunnel *t) { if (NULL == t) { GNUNET_assert (0); return (enum CadetTunnelCState) -1; } return t->cstate; } /** * Get the encryption state of a tunnel. * * @param t Tunnel. * * @return Tunnel's encryption state. */ enum CadetTunnelEState GCT_get_estate (struct CadetTunnel *t) { if (NULL == t) { GNUNET_break (0); return (enum CadetTunnelEState) -1; } return t->estate; } /** * Get the maximum buffer space for a tunnel towards a local client. * * @param t Tunnel. * * @return Biggest buffer space offered by any channel in the tunnel. */ unsigned int GCT_get_channels_buffer (struct CadetTunnel *t) { struct CadetTChannel *iter; unsigned int buffer; unsigned int ch_buf; if (NULL == t->channel_head) { /* Probably getting buffer for a channel create/handshake. */ return 64; } buffer = 0; for (iter = t->channel_head; NULL != iter; iter = iter->next) { ch_buf = get_channel_buffer (iter); if (ch_buf > buffer) buffer = ch_buf; } return buffer; } /** * Get the total buffer space for a tunnel for P2P traffic. * * @param t Tunnel. * * @return Buffer space offered by all connections in the tunnel. */ unsigned int GCT_get_connections_buffer (struct CadetTunnel *t) { struct CadetTConnection *iter; unsigned int buffer; if (GNUNET_NO == is_ready (t)) { if (count_queued_data (t) > 3) return 0; else return 1; } buffer = 0; for (iter = t->connection_head; NULL != iter; iter = iter->next) { if (GCC_get_state (iter->c) != CADET_CONNECTION_READY) { continue; } buffer += get_connection_buffer (iter); } return buffer; } /** * Get the tunnel's destination. * * @param t Tunnel. * * @return ID of the destination peer. */ const struct GNUNET_PeerIdentity * GCT_get_destination (struct CadetTunnel *t) { return GCP_get_id (t->peer); } /** * Get the tunnel's next free global channel ID. * * @param t Tunnel. * * @return GID of a channel free to use. */ CADET_ChannelNumber GCT_get_next_chid (struct CadetTunnel *t) { CADET_ChannelNumber chid; CADET_ChannelNumber mask; int result; /* Set bit 30 depending on the ID relationship. Bit 31 is always 0 for GID. * If our ID is bigger or loopback tunnel, start at 0, bit 30 = 0 * If peer's ID is bigger, start at 0x4... bit 30 = 1 */ result = GNUNET_CRYPTO_cmp_peer_identity (&my_full_id, GCP_get_id (t->peer)); if (0 > result) mask = 0x40000000; else mask = 0x0; t->next_chid |= mask; while (NULL != GCT_get_channel (t, t->next_chid)) { LOG (GNUNET_ERROR_TYPE_DEBUG, "Channel %u exists...\n", t->next_chid); t->next_chid = (t->next_chid + 1) & ~GNUNET_CADET_LOCAL_CHANNEL_ID_CLI; t->next_chid |= mask; } chid = t->next_chid; t->next_chid = (t->next_chid + 1) & ~GNUNET_CADET_LOCAL_CHANNEL_ID_CLI; t->next_chid |= mask; return chid; } /** * Send ACK on one or more channels due to buffer in connections. * * @param t Channel which has some free buffer space. */ void GCT_unchoke_channels (struct CadetTunnel *t) { struct CadetTChannel *iter; unsigned int buffer; unsigned int channels = GCT_count_channels (t); unsigned int choked_n; struct CadetChannel *choked[channels]; LOG (GNUNET_ERROR_TYPE_DEBUG, "GCT_unchoke_channels on %s\n", GCT_2s (t)); LOG (GNUNET_ERROR_TYPE_DEBUG, " head: %p\n", t->channel_head); if (NULL != t->channel_head) LOG (GNUNET_ERROR_TYPE_DEBUG, " head ch: %p\n", t->channel_head->ch); /* Get buffer space */ buffer = GCT_get_connections_buffer (t); if (0 == buffer) { return; } /* Count and remember choked channels */ choked_n = 0; for (iter = t->channel_head; NULL != iter; iter = iter->next) { if (GNUNET_NO == get_channel_allowed (iter)) { choked[choked_n++] = iter->ch; } } /* Unchoke random channels */ while (0 < buffer && 0 < choked_n) { unsigned int r = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK, choked_n); GCCH_allow_client (choked[r], GCCH_is_origin (choked[r], GNUNET_YES)); choked_n--; buffer--; choked[r] = choked[choked_n]; } } /** * Send ACK on one or more connections due to buffer space to the client. * * Iterates all connections of the tunnel and sends ACKs appropriately. * * @param t Tunnel. */ void GCT_send_connection_acks (struct CadetTunnel *t) { struct CadetTConnection *iter; uint32_t allowed; uint32_t to_allow; uint32_t allow_per_connection; unsigned int cs; unsigned int buffer; LOG (GNUNET_ERROR_TYPE_DEBUG, "Tunnel send connection ACKs on %s\n", GCT_2s (t)); if (NULL == t) { GNUNET_break (0); return; } buffer = GCT_get_channels_buffer (t); LOG (GNUNET_ERROR_TYPE_DEBUG, " buffer %u\n", buffer); /* Count connections, how many messages are already allowed */ cs = GCT_count_connections (t); for (allowed = 0, iter = t->connection_head; NULL != iter; iter = iter->next) { allowed += get_connection_allowed (iter); } LOG (GNUNET_ERROR_TYPE_DEBUG, " allowed %u\n", allowed); /* Make sure there is no overflow */ if (allowed > buffer) { return; } /* Authorize connections to send more data */ to_allow = buffer; /* - allowed; */ for (iter = t->connection_head; NULL != iter && to_allow > 0; iter = iter->next) { allow_per_connection = to_allow/cs; to_allow -= allow_per_connection; cs--; if (get_connection_allowed (iter) > 64 / 3) { continue; } GCC_allow (iter->c, allow_per_connection, GCC_is_origin (iter->c, GNUNET_NO)); } GNUNET_break (to_allow == 0); //FIXME tripped } /** * Cancel a previously sent message while it's in the queue. * * ONLY can be called before the continuation given to the send function * is called. Once the continuation is called, the message is no longer in the * queue. * * @param q Handle to the queue. */ void GCT_cancel (struct CadetTunnelQueue *q) { if (NULL != q->cq) { GCC_cancel (q->cq); /* tun_message_sent() will be called and free q */ } else if (NULL != q->tqd) { unqueue_data (q->tqd); q->tqd = NULL; if (NULL != q->cont) q->cont (q->cont_cls, NULL, q, 0, 0); GNUNET_free (q); } else { GNUNET_break (0); } } /** * Sends an already built message on a tunnel, encrypting it and * choosing the best connection if not provided. * * @param message Message to send. Function modifies it. * @param t Tunnel on which this message is transmitted. * @param c Connection to use (autoselect if NULL). * @param force Force the tunnel to take the message (buffer overfill). * @param cont Continuation to call once message is really sent. * @param cont_cls Closure for @c cont. * * @return Handle to cancel message. NULL if @c cont is NULL. */ struct CadetTunnelQueue * GCT_send_prebuilt_message (const struct GNUNET_MessageHeader *message, struct CadetTunnel *t, struct CadetConnection *c, int force, GCT_sent cont, void *cont_cls) { return send_prebuilt_message (message, t, c, force, cont, cont_cls, NULL); } /** * Sends an already built and encrypted message on a tunnel, choosing the best * connection. Useful for re-queueing messages queued on a destroyed connection. * * @param message Message to send. Function modifies it. * @param t Tunnel on which this message is transmitted. */ void GCT_resend_message (const struct GNUNET_MessageHeader *message, struct CadetTunnel *t) { struct CadetConnection *c; int fwd; c = tunnel_get_connection (t); if (NULL == c) { /* TODO queue in tunnel, marked as encrypted */ LOG (GNUNET_ERROR_TYPE_DEBUG, "No connection available, dropping.\n"); return; } fwd = GCC_is_origin (c, GNUNET_YES); GNUNET_break (NULL == GCC_send_prebuilt_message (message, 0, 0, c, fwd, GNUNET_YES, NULL, NULL)); } /** * Is the tunnel directed towards the local peer? * * @param t Tunnel. * * @return #GNUNET_YES if it is loopback. */ int GCT_is_loopback (const struct CadetTunnel *t) { return (myid == GCP_get_short_id (t->peer)); } /** * Is the tunnel this path already? * * @param t Tunnel. * @param p Path. * * @return #GNUNET_YES a connection uses this path. */ int GCT_is_path_used (const struct CadetTunnel *t, const struct CadetPeerPath *p) { struct CadetTConnection *iter; for (iter = t->connection_head; NULL != iter; iter = iter->next) if (GCC_get_path (iter->c) == p) return GNUNET_YES; return GNUNET_NO; } /** * Get a cost of a path for a tunnel considering existing connections. * * @param t Tunnel. * @param path Candidate path. * * @return Cost of the path (path length + number of overlapping nodes) */ unsigned int GCT_get_path_cost (const struct CadetTunnel *t, const struct CadetPeerPath *path) { struct CadetTConnection *iter; const struct CadetPeerPath *aux; unsigned int overlap; unsigned int i; unsigned int j; if (NULL == path) return 0; overlap = 0; GNUNET_assert (NULL != t); for (i = 0; i < path->length; i++) { for (iter = t->connection_head; NULL != iter; iter = iter->next) { aux = GCC_get_path (iter->c); if (NULL == aux) continue; for (j = 0; j < aux->length; j++) { if (path->peers[i] == aux->peers[j]) { overlap++; break; } } } } return path->length + overlap; } /** * Get the static string for the peer this tunnel is directed. * * @param t Tunnel. * * @return Static string the destination peer's ID. */ const char * GCT_2s (const struct CadetTunnel *t) { if (NULL == t) return "(NULL)"; return GCP_2s (t->peer); } /******************************************************************************/ /***************************** INFO/DEBUG *******************************/ /******************************************************************************/ /** * Log all possible info about the tunnel state. * * @param t Tunnel to debug. * @param level Debug level to use. */ void GCT_debug (const struct CadetTunnel *t, enum GNUNET_ErrorType level) { struct CadetTChannel *iterch; struct CadetTConnection *iterc; int do_log; do_log = GNUNET_get_log_call_status (level & (~GNUNET_ERROR_TYPE_BULK), "cadet-tun", __FILE__, __FUNCTION__, __LINE__); if (0 == do_log) return; LOG2 (level, "TTT DEBUG TUNNEL TOWARDS %s\n", GCT_2s (t)); LOG2 (level, "TTT cstate %s, estate %s\n", cstate2s (t->cstate), estate2s (t->estate)); LOG2 (level, "TTT kx_ctx %p, rekey_task %u, finish task %u\n", t->kx_ctx, t->rekey_task, t->kx_ctx ? t->kx_ctx->finish_task : 0); #if DUMP_KEYS_TO_STDERR LOG2 (level, "TTT my EPHM\t %s\n", GNUNET_h2s ((struct GNUNET_HashCode *) &kx_msg.ephemeral_key)); LOG2 (level, "TTT peers EPHM:\t %s\n", GNUNET_h2s ((struct GNUNET_HashCode *) &t->peers_ephemeral_key)); LOG2 (level, "TTT ENC key:\t %s\n", GNUNET_h2s ((struct GNUNET_HashCode *) &t->e_key)); LOG2 (level, "TTT DEC key:\t %s\n", GNUNET_h2s ((struct GNUNET_HashCode *) &t->d_key)); if (t->kx_ctx) { LOG2 (level, "TTT OLD ENC key:\t %s\n", GNUNET_h2s ((struct GNUNET_HashCode *) &t->kx_ctx->e_key_old)); LOG2 (level, "TTT OLD DEC key:\t %s\n", GNUNET_h2s ((struct GNUNET_HashCode *) &t->kx_ctx->d_key_old)); } #endif LOG2 (level, "TTT tq_head %p, tq_tail %p\n", t->tq_head, t->tq_tail); LOG2 (level, "TTT destroy %u\n", t->destroy_task); LOG2 (level, "TTT channels:\n"); for (iterch = t->channel_head; NULL != iterch; iterch = iterch->next) { LOG2 (level, "TTT - %s\n", GCCH_2s (iterch->ch)); } LOG2 (level, "TTT connections:\n"); for (iterc = t->connection_head; NULL != iterc; iterc = iterc->next) { GCC_debug (iterc->c, level); } LOG2 (level, "TTT DEBUG TUNNEL END\n"); } /** * Iterate all tunnels. * * @param iter Iterator. * @param cls Closure for @c iter. */ void GCT_iterate_all (GNUNET_CONTAINER_PeerMapIterator iter, void *cls) { GNUNET_CONTAINER_multipeermap_iterate (tunnels, iter, cls); } /** * Count all tunnels. * * @return Number of tunnels to remote peers kept by this peer. */ unsigned int GCT_count_all (void) { return GNUNET_CONTAINER_multipeermap_size (tunnels); } /** * Iterate all connections of a tunnel. * * @param t Tunnel whose connections to iterate. * @param iter Iterator. * @param cls Closure for @c iter. */ void GCT_iterate_connections (struct CadetTunnel *t, GCT_conn_iter iter, void *cls) { struct CadetTConnection *ct; for (ct = t->connection_head; NULL != ct; ct = ct->next) iter (cls, ct->c); } /** * Iterate all channels of a tunnel. * * @param t Tunnel whose channels to iterate. * @param iter Iterator. * @param cls Closure for @c iter. */ void GCT_iterate_channels (struct CadetTunnel *t, GCT_chan_iter iter, void *cls) { struct CadetTChannel *cht; for (cht = t->channel_head; NULL != cht; cht = cht->next) iter (cls, cht->ch); }