/* This file is part of GNUnet (C) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 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 2, 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. */ /** * @file transport/plugin_transport_tcp.c * @brief Implementation of the TCP transport service * @author Christian Grothoff */ #include "platform.h" #include "gnunet_hello_lib.h" #include "gnunet_network_lib.h" #include "gnunet_os_lib.h" #include "gnunet_peerinfo_service.h" #include "gnunet_protocols.h" #include "gnunet_resolver_service.h" #include "gnunet_server_lib.h" #include "gnunet_service_lib.h" #include "gnunet_statistics_service.h" #include "gnunet_transport_service.h" #include "plugin_transport.h" #include "transport.h" #define DEBUG_TCP GNUNET_NO /** * After how long do we expire an address that we * learned from another peer if it is not reconfirmed * by anyone? */ #define LEARNED_ADDRESS_EXPIRATION GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_HOURS, 6) /** * How long until we give up on transmitting the welcome message? */ #define WELCOME_TIMEOUT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 30) /** * How long until we give up on transmitting the welcome message? */ #define HOSTNAME_RESOLVE_TIMEOUT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 5) /** * For how many messages back to we keep transmission times? */ #define ACK_LOG_SIZE 32 /** * Initial handshake message for a session. This header * is followed by the address that the other peer used to * connect to us (so that we may learn it) or the address * that the other peer got from the accept call. */ struct WelcomeMessage { struct GNUNET_MessageHeader header; /** * Identity of the node connecting (TCP client) */ struct GNUNET_PeerIdentity clientIdentity; }; /** * Encapsulation for normal TCP traffic. */ struct DataMessage { struct GNUNET_MessageHeader header; /** * For alignment. */ uint32_t reserved GNUNET_PACKED; /** * Number of the last message that was received from the other peer. */ uint64_t ack_in GNUNET_PACKED; /** * Number of this outgoing message. */ uint64_t ack_out GNUNET_PACKED; /** * How long was sending this ack delayed by the other peer * (estimate). The receiver of this message can use the delay * between sending his message number 'ack' and receiving this ack * minus the delay as an estimate of the round-trip time. */ struct GNUNET_TIME_RelativeNBO delay; }; /** * Encapsulation of all of the state of the plugin. */ struct Plugin; /** * Information kept for each message that is yet to * be transmitted. */ struct PendingMessage { /** * This is a linked list. */ struct PendingMessage *next; /** * The pending message, pointer to the end * of this struct, do not free! */ struct GNUNET_MessageHeader *msg; /** * Continuation function to call once the message * has been sent. Can be NULL if there is no * continuation to call. */ GNUNET_TRANSPORT_TransmitContinuation transmit_cont; /** * Closure for transmit_cont. */ void *transmit_cont_cls; /** * Timeout value for the pending message. */ struct GNUNET_TIME_Absolute timeout; /** * GNUNET_YES if this is a welcome message; * otherwise this should be a DATA message. */ int is_welcome; }; /** * Session handle for TCP connections. */ struct Session { /** * Stored in a linked list. */ struct Session *next; /** * Pointer to the global plugin struct. */ struct Plugin *plugin; /** * The client (used to identify this connection) */ struct GNUNET_SERVER_Client *client; /** * gnunet-service-transport context for this connection. */ struct ReadyList *service_context; /** * Messages currently pending for transmission * to this peer, if any. */ struct PendingMessage *pending_messages; /** * Handle for pending transmission request. */ struct GNUNET_NETWORK_TransmitHandle *transmit_handle; /** * To whom are we talking to (set to our identity * if we are still waiting for the welcome message) */ struct GNUNET_PeerIdentity target; /** * At what time did we reset last_received last? */ struct GNUNET_TIME_Absolute last_quota_update; /** * Address of the other peer if WE initiated the connection * (and hence can be sure what it is), otherwise NULL. */ void *connect_addr; /** * How many bytes have we received since the "last_quota_update" * timestamp? */ uint64_t last_received; /** * Our current latency estimate (in ms). */ double latency_estimate; /** * Time when we generated the last ACK_LOG_SIZE acks. * (the "last" refers to the "out_msg_counter" here) */ struct GNUNET_TIME_Absolute gen_time[ACK_LOG_SIZE]; /** * Our current sequence number. */ uint64_t out_msg_counter; /** * Highest received incoming sequence number. */ uint64_t max_in_msg_counter; /** * Number of bytes per ms that this peer is allowed * to send to us. */ uint32_t quota_in; /** * Length of connect_addr, can be 0. */ size_t connect_alen; /** * Are we still expecting the welcome message? (GNUNET_YES/GNUNET_NO) */ int expecting_welcome; /** * Are we still trying to connect? */ int still_connecting; }; /** * Encapsulation of all of the state of the plugin. */ struct Plugin { /** * Our environment. */ struct GNUNET_TRANSPORT_PluginEnvironment *env; /** * The listen socket. */ struct GNUNET_NETWORK_SocketHandle *lsock; /** * List of open TCP sessions. */ struct Session *sessions; /** * Handle for the statistics service. */ struct GNUNET_STATISTICS_Handle *statistics; /** * Handle to the network service. */ struct GNUNET_SERVICE_Context *service; /** * Handle to the server for this service. */ struct GNUNET_SERVER_Handle *server; /** * Copy of the handler array where the closures are * set to this struct's instance. */ struct GNUNET_SERVER_MessageHandler *handlers; /** * ID of task used to update our addresses when one expires. */ GNUNET_SCHEDULER_TaskIdentifier address_update_task; /** * Port that we are actually listening on. */ uint16_t open_port; /** * Port that the user said we would have visible to the * rest of the world. */ uint16_t adv_port; }; /** * Find the session handle for the given peer. */ static struct Session * find_session_by_target (struct Plugin *plugin, const struct GNUNET_PeerIdentity *target) { struct Session *ret; ret = plugin->sessions; while ((ret != NULL) && (0 != memcmp (target, &ret->target, sizeof (struct GNUNET_PeerIdentity)))) ret = ret->next; return ret; } /** * Find the session handle for the given peer. */ static struct Session * find_session_by_client (struct Plugin *plugin, const struct GNUNET_SERVER_Client *client) { struct Session *ret; ret = plugin->sessions; while ((ret != NULL) && (client != ret->client)) ret = ret->next; return ret; } /** * Create a welcome message. */ static struct PendingMessage * create_welcome (size_t addrlen, const void *addr, struct Plugin *plugin) { struct PendingMessage *pm; struct WelcomeMessage *welcome; pm = GNUNET_malloc (sizeof (struct PendingMessage) + sizeof (struct WelcomeMessage) + addrlen); pm->msg = (struct GNUNET_MessageHeader *) &pm[1]; welcome = (struct WelcomeMessage *) &pm[1]; welcome->header.size = htons (sizeof (struct WelcomeMessage) + addrlen); welcome->header.type = htons (GNUNET_MESSAGE_TYPE_TRANSPORT_TCP_WELCOME); GNUNET_CRYPTO_hash (plugin->env->my_public_key, sizeof (struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded), &welcome->clientIdentity.hashPubKey); memcpy (&welcome[1], addr, addrlen); pm->timeout = GNUNET_TIME_relative_to_absolute (WELCOME_TIMEOUT); pm->is_welcome = GNUNET_YES; return pm; } /** * Create a new session using the specified address * for the welcome message. * * @param plugin us * @param target peer to connect to * @param client client to use * @param addrlen IPv4 or IPv6 * @param addr either struct sockaddr_in or struct sockaddr_in6 * @return NULL connection failed / invalid address */ static struct Session * create_session (struct Plugin *plugin, const struct GNUNET_PeerIdentity *target, struct GNUNET_SERVER_Client *client, const void *addr, size_t addrlen) { struct Session *ret; ret = GNUNET_malloc (sizeof (struct Session)); ret->plugin = plugin; ret->next = plugin->sessions; plugin->sessions = ret; ret->client = client; ret->target = *target; ret->last_quota_update = GNUNET_TIME_absolute_get (); ret->quota_in = plugin->env->default_quota_in; ret->expecting_welcome = GNUNET_YES; ret->pending_messages = create_welcome (addrlen, addr, plugin); return ret; } /** * Create a new session connecting to the specified * target at the specified address. * * @param plugin us * @param target peer to connect to * @param addrlen IPv4 or IPv6 * @param addr either struct sockaddr_in or struct sockaddr_in6 * @return NULL connection failed / invalid address */ static struct Session * connect_and_create_session (struct Plugin *plugin, const struct GNUNET_PeerIdentity *target, const void *addr, size_t addrlen) { struct GNUNET_SERVER_Client *client; struct GNUNET_NETWORK_SocketHandle *conn; struct Session *session; int af; char buf[INET6_ADDRSTRLEN]; uint16_t port; session = plugin->sessions; while (session != NULL) { if ((0 == memcmp (target, &session->target, sizeof (struct GNUNET_PeerIdentity))) && (session->connect_alen == addrlen) && (0 == memcmp (session->connect_addr, addr, addrlen))) return session; /* already exists! */ session = session->next; } if (addrlen == sizeof (struct sockaddr_in)) { af = AF_INET; inet_ntop (af, &((struct sockaddr_in *) addr)->sin_addr, buf, sizeof (buf)); port = ntohs (((struct sockaddr_in *) addr)->sin_port); } else if (addrlen == sizeof (struct sockaddr_in6)) { af = AF_INET6; inet_ntop (af, &((struct sockaddr_in6 *) addr)->sin6_addr, buf, sizeof (buf)); port = ntohs (((struct sockaddr_in6 *) addr)->sin6_port); } else { GNUNET_break_op (0); return NULL; /* invalid address */ } conn = GNUNET_NETWORK_socket_create_from_sockaddr (plugin->env->sched, af, addr, addrlen, GNUNET_SERVER_MAX_MESSAGE_SIZE); if (conn == NULL) { #if DEBUG_TCP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "Failed to create connection to peer at `%s:%u'.\n", buf, port); #endif return NULL; } client = GNUNET_SERVER_connect_socket (plugin->server, conn); GNUNET_assert (client != NULL); session = create_session (plugin, target, client, addr, addrlen); session->connect_alen = addrlen; session->connect_addr = GNUNET_malloc (addrlen); memcpy (session->connect_addr, addr, addrlen); #if DEBUG_TCP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "Creating new session %p with `%s:%u' based on `%s' request.\n", session, buf, port, "send_to"); #endif return session; } /** * If we have pending messages, ask the server to * transmit them (schedule the respective tasks, etc.) * * @param session for which session should we do this */ static void process_pending_messages (struct Session *session); /** * Function called to notify a client about the socket * begin ready to queue more data. "buf" will be * NULL and "size" zero if the socket was closed for * writing in the meantime. * * @param cls closure * @param size number of bytes available in buf * @param buf where the callee should write the message * @return number of bytes written to buf */ static size_t do_transmit (void *cls, size_t size, void *buf) { struct Session *session = cls; struct PendingMessage *pm; char *cbuf; uint16_t msize; size_t ret; struct DataMessage *dm; session->transmit_handle = NULL; if (buf == NULL) { #if DEBUG_TCP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "Timeout trying to transmit\n"); #endif /* timeout */ while (NULL != (pm = session->pending_messages)) { session->pending_messages = pm->next; if (pm->transmit_cont != NULL) pm->transmit_cont (pm->transmit_cont_cls, session->service_context, &session->target, GNUNET_SYSERR); GNUNET_free (pm); } return 0; } ret = 0; cbuf = buf; while (NULL != (pm = session->pending_messages)) { if (pm->is_welcome) { if (size < (msize = htons (pm->msg->size))) break; memcpy (cbuf, pm->msg, msize); cbuf += msize; ret += msize; size -= msize; } else { if (size < sizeof (struct DataMessage) + (msize = htons (pm->msg->size))) break; dm = (struct DataMessage *) cbuf; dm->header.size = htons (sizeof (struct DataMessage) + msize); dm->header.type = htons (GNUNET_MESSAGE_TYPE_TRANSPORT_TCP_DATA); dm->ack_out = GNUNET_htonll (++session->out_msg_counter); dm->ack_in = GNUNET_htonll (session->max_in_msg_counter); cbuf += sizeof (struct DataMessage); ret += sizeof (struct DataMessage); size -= sizeof (struct DataMessage); memcpy (cbuf, pm->msg, msize); cbuf += msize; ret += msize; size -= msize; } session->pending_messages = pm->next; if (pm->transmit_cont != NULL) pm->transmit_cont (pm->transmit_cont_cls, session->service_context, &session->target, GNUNET_OK); GNUNET_free (pm); session->gen_time[session->out_msg_counter % ACK_LOG_SIZE] = GNUNET_TIME_absolute_get (); } process_pending_messages (session); #if DEBUG_TCP || 1 GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "Transmitting %u bytes\n", ret); #endif return ret; } /** * If we have pending messages, ask the server to * transmit them (schedule the respective tasks, etc.) * * @param session for which session should we do this */ static void process_pending_messages (struct Session *session) { GNUNET_assert (session->client != NULL); if (session->pending_messages == NULL) return; if (session->transmit_handle != NULL) return; session->transmit_handle = GNUNET_SERVER_notify_transmit_ready (session->client, htons (session-> pending_messages->msg-> size) + (session-> pending_messages->is_welcome ? 0 : sizeof (struct DataMessage)), GNUNET_TIME_absolute_get_remaining (session-> pending_messages[0].timeout), &do_transmit, session); } /** * Function that can be used by the transport service to transmit * a message using the plugin using a fresh connection (even if * we already have a connection to this peer, this function is * required to establish a new one). * * @param cls closure * @param target who should receive this message * @param msg1 first message to transmit * @param msg2 second message to transmit (can be NULL) * @param timeout how long should we try to transmit these? * @param addrlen length of the address * @param addr the address * @return session if the transmission has been scheduled * NULL if the address format is invalid */ static void * tcp_plugin_send_to (void *cls, const struct GNUNET_PeerIdentity *target, const struct GNUNET_MessageHeader *msg1, const struct GNUNET_MessageHeader *msg2, struct GNUNET_TIME_Relative timeout, const void *addr, size_t addrlen) { struct Plugin *plugin = cls; struct Session *session; struct PendingMessage *pl; struct PendingMessage *pm; session = connect_and_create_session (plugin, target, addr, addrlen); if (session == NULL) { #if DEBUG_TCP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "Failed to create fresh session.\n"); #endif return NULL; } pl = NULL; if (msg2 != NULL) { pm = GNUNET_malloc (sizeof (struct PendingMessage) + ntohs (msg2->size)); pm->msg = (struct GNUNET_MessageHeader *) &pm[1]; memcpy (pm->msg, msg2, ntohs (msg2->size)); pm->timeout = GNUNET_TIME_relative_to_absolute (timeout); pm->is_welcome = GNUNET_NO; pl = pm; } if (msg1 != NULL) { pm = GNUNET_malloc (sizeof (struct PendingMessage) + ntohs (msg1->size)); pm->msg = (struct GNUNET_MessageHeader *) &pm[1]; memcpy (pm->msg, msg1, ntohs (msg1->size)); pm->timeout = GNUNET_TIME_relative_to_absolute (timeout); pm->is_welcome = GNUNET_NO; pm->next = pl; pl = pm; } /* append */ if (session->pending_messages != NULL) { pm = session->pending_messages; while (pm->next != NULL) pm = pm->next; pm->next = pl; } else { session->pending_messages = pl; } process_pending_messages (session); return session; } /** * Functions with this signature are called whenever we need * to close a session due to a disconnect or failure to * establish a connection. * * @param session session to close down */ static void disconnect_session (struct Session *session) { struct Session *prev; struct Session *pos; struct PendingMessage *pm; #if DEBUG_TCP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "Disconnecting from other peer (session %p).\n", session); #endif /* remove from session list */ prev = NULL; pos = session->plugin->sessions; while (pos != session) { prev = pos; pos = pos->next; } if (prev == NULL) session->plugin->sessions = session->next; else prev->next = session->next; /* clean up state */ if (session->client != NULL) { #if DEBUG_TCP GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Disconnecting from client address %p\n", session->client); #endif GNUNET_SERVER_client_drop (session->client); session->client = NULL; } if (session->transmit_handle != NULL) { GNUNET_NETWORK_notify_transmit_ready_cancel (session->transmit_handle); session->transmit_handle = NULL; } while (NULL != (pm = session->pending_messages)) { session->pending_messages = pm->next; if (NULL != pm->transmit_cont) pm->transmit_cont (pm->transmit_cont_cls, session->service_context, &session->target, GNUNET_SYSERR); GNUNET_free (pm); } /* notify transport service about disconnect */ session->plugin->env->receive (session->plugin->env->cls, session, session->service_context, GNUNET_TIME_UNIT_ZERO, &session->target, NULL); GNUNET_free_non_null (session->connect_addr); GNUNET_free (session); } /** * Iterator callback to go over all addresses. If we get * a TCP address, increment the counter * * @param cls closure, points to the counter * @param tname name of the transport * @param expiration expiration time * @param addr the address * @param addrlen length of the address * @return GNUNET_OK to keep the address, * GNUNET_NO to delete it from the HELLO * GNUNET_SYSERR to stop iterating (but keep current address) */ static int count_tcp_addresses (void *cls, const char *tname, struct GNUNET_TIME_Absolute expiration, const void *addr, size_t addrlen) { unsigned int *counter = cls; if (0 != strcmp (tname, "tcp")) return GNUNET_OK; /* not one of ours */ (*counter)++; return GNUNET_OK; /* failed to connect */ } struct ConnectContext { struct Plugin *plugin; struct GNUNET_NETWORK_SocketHandle *sa; struct PendingMessage *welcome; unsigned int pos; }; /** * Iterator callback to go over all addresses. If we get * the "pos" TCP address, try to connect to it. * * @param cls closure * @param tname name of the transport * @param expiration expiration time * @param addrlen length of the address * @param addr the address * @return GNUNET_OK to keep the address, * GNUNET_NO to delete it from the HELLO * GNUNET_SYSERR to stop iterating (but keep current address) */ static int try_connect_to_address (void *cls, const char *tname, struct GNUNET_TIME_Absolute expiration, const void *addr, size_t addrlen) { struct ConnectContext *cc = cls; int af; if (0 != strcmp (tname, "tcp")) return GNUNET_OK; /* not one of ours */ if (sizeof (struct sockaddr_in) == addrlen) af = AF_INET; else if (sizeof (struct sockaddr_in6) == addrlen) af = AF_INET6; else { /* not a valid address */ GNUNET_break (0); return GNUNET_NO; } if (0 == cc->pos--) { cc->welcome = create_welcome (addrlen, addr, cc->plugin); cc->sa = GNUNET_NETWORK_socket_create_from_sockaddr (cc->plugin->env->sched, af, addr, addrlen, GNUNET_SERVER_MAX_MESSAGE_SIZE); #if DEBUG_TCP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "Connected to other peer.\n"); #endif return GNUNET_SYSERR; } return GNUNET_OK; /* failed to connect */ } /** * Type of an iterator over the hosts. Note that each * host will be called with each available protocol. * * @param cls closure * @param peer id of the peer, NULL for last call * @param hello hello message for the peer (can be NULL) * @param trust amount of trust we have in the peer */ static void session_try_connect (void *cls, const struct GNUNET_PeerIdentity *peer, const struct GNUNET_HELLO_Message *hello, uint32_t trust) { struct Session *session = cls; unsigned int count; struct ConnectContext cctx; struct PendingMessage *pm; if (peer == NULL) { /* last call, destroy session if we are still not connected */ if (session->still_connecting == GNUNET_NO) { #if DEBUG_TCP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "Connected to other peer, now processing messages.\n"); #endif process_pending_messages (session); } else { #if DEBUG_TCP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "Failed to connect to other peer, now closing session.\n"); #endif disconnect_session (session); } return; } if ((hello == NULL) || (session->client != NULL)) { GNUNET_break (0); /* should this ever happen!? */ return; } count = 0; GNUNET_HELLO_iterate_addresses (hello, GNUNET_NO, &count_tcp_addresses, &count); if (count == 0) { #if DEBUG_TCP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "Asked to connect, but have no addresses to try.\n"); #endif return; } cctx.plugin = session->plugin; cctx.sa = NULL; cctx.welcome = NULL; cctx.pos = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK, count); GNUNET_HELLO_iterate_addresses (hello, GNUNET_NO, &try_connect_to_address, &cctx); if (cctx.sa == NULL) { #if DEBUG_TCP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "Asked to connect, but all addresses failed.\n"); #endif GNUNET_free_non_null (cctx.welcome); return; } session->client = GNUNET_SERVER_connect_socket (session->plugin->server, cctx.sa); #if DEBUG_TCP GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Connected getting client address %p\n", session->client); #endif if (session->client == NULL) { GNUNET_break (0); /* how could this happen? */ GNUNET_free_non_null (cctx.welcome); return; } pm = cctx.welcome; /* prepend (!) */ pm->next = session->pending_messages; session->pending_messages = pm; session->still_connecting = GNUNET_NO; #if DEBUG_TCP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "Connected to other peer, now sending `%s' message.\n", "WELCOME"); #endif } /** * Function that can be used by the transport service to transmit * a message using the plugin. * * @param cls closure * @param plugin_context value we were asked to pass to this plugin * to respond to the given peer (use is optional, * but may speed up processing), can be NULL * @param service_context value passed to the transport-service * to identify the neighbour * @param target who should receive this message * @param msg the message to transmit * @param cont continuation to call once the message has * been transmitted (or if the transport is ready * for the next transmission call; or if the * peer disconnected...) * @param cont_cls closure for cont * @return plugin_context that should be used next time for * sending messages to the specified peer */ static void * tcp_plugin_send (void *cls, void *plugin_context, struct ReadyList *service_context, const struct GNUNET_PeerIdentity *target, const struct GNUNET_MessageHeader *msg, struct GNUNET_TIME_Relative timeout, GNUNET_TRANSPORT_TransmitContinuation cont, void *cont_cls) { struct Plugin *plugin = cls; struct Session *session = plugin_context; struct PendingMessage *pm; struct PendingMessage *pme; if (session == NULL) session = find_session_by_target (plugin, target); pm = GNUNET_malloc (sizeof (struct PendingMessage) + ntohs (msg->size)); pm->msg = (struct GNUNET_MessageHeader *) &pm[1]; memcpy (pm->msg, msg, ntohs (msg->size)); pm->timeout = GNUNET_TIME_relative_to_absolute (timeout); pm->transmit_cont = cont; pm->transmit_cont_cls = cont_cls; if (session == NULL) { session = GNUNET_malloc (sizeof (struct Session)); #if DEBUG_TCP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "Asked to transmit, creating fresh session %p.\n", session); #endif session->next = plugin->sessions; plugin->sessions = session; session->plugin = plugin; session->target = *target; session->last_quota_update = GNUNET_TIME_absolute_get (); session->quota_in = plugin->env->default_quota_in; session->expecting_welcome = GNUNET_YES; session->still_connecting = GNUNET_YES; session->pending_messages = pm; GNUNET_PEERINFO_for_all (plugin->env->cfg, plugin->env->sched, target, 0, timeout, &session_try_connect, session); return session; } GNUNET_assert (session != NULL); GNUNET_assert (session->still_connecting == GNUNET_NO); /* append pm to pending_messages list */ pme = session->pending_messages; if (pme == NULL) { session->pending_messages = pm; } else { while (NULL != pme->next) pme = pme->next; pme->next = pm; } #if DEBUG_TCP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "Asked to transmit, added message to list.\n"); #endif process_pending_messages (session); return session; } /** * Function that can be called to force a disconnect from the * specified neighbour. This should also cancel all previously * scheduled transmissions. Obviously the transmission may have been * partially completed already, which is OK. The plugin is supposed * to close the connection (if applicable) and no longer call the * transmit continuation(s). * * Finally, plugin MUST NOT call the services's receive function to * notify the service that the connection to the specified target was * closed after a getting this call. * * @param cls closure * @param plugin_context value we were asked to pass to this plugin * to respond to the given peer (use is optional, * but may speed up processing), can be NULL (if * NULL was returned from the transmit function) * @param service_context must correspond to the service context * of the corresponding Transmit call; the plugin should * not cancel a send call made with a different service * context pointer! Never NULL. * @param target peer for which the last transmission is * to be cancelled */ static void tcp_plugin_cancel (void *cls, void *plugin_context, struct ReadyList *service_context, const struct GNUNET_PeerIdentity *target) { struct Plugin *plugin = cls; struct PendingMessage *pm; struct Session *session; struct Session *next; session = plugin->sessions; while (session != NULL) { next = session->next; if (0 == memcmp (target, &session->target, sizeof (struct GNUNET_PeerIdentity))) { pm = session->pending_messages; while (pm != NULL) { pm->transmit_cont = NULL; pm->transmit_cont_cls = NULL; pm = pm->next; } session->service_context = NULL; GNUNET_SERVER_client_disconnect (session->client); /* rest of the clean-up of the session will be done as part of disconnect_notify which should be triggered any time now */ } session = next; } } struct PrettyPrinterContext { GNUNET_TRANSPORT_AddressStringCallback asc; void *asc_cls; uint16_t port; }; /** * Append our port and forward the result. */ static void append_port (void *cls, const char *hostname) { struct PrettyPrinterContext *ppc = cls; char *ret; if (hostname == NULL) { ppc->asc (ppc->asc_cls, NULL); GNUNET_free (ppc); return; } GNUNET_asprintf (&ret, "%s:%d", hostname, ppc->port); ppc->asc (ppc->asc_cls, ret); GNUNET_free (ret); } /** * Convert the transports address to a nice, human-readable * format. * * @param cls closure * @param name name of the transport that generated the address * @param addr one of the addresses of the host, NULL for the last address * the specific address format depends on the transport * @param addrlen length of the address * @param numeric should (IP) addresses be displayed in numeric form? * @param timeout after how long should we give up? * @param asc function to call on each string * @param asc_cls closure for asc */ static void tcp_plugin_address_pretty_printer (void *cls, const char *type, const void *addr, size_t addrlen, int numeric, struct GNUNET_TIME_Relative timeout, GNUNET_TRANSPORT_AddressStringCallback asc, void *asc_cls) { struct Plugin *plugin = cls; const struct sockaddr_in *v4; const struct sockaddr_in6 *v6; struct PrettyPrinterContext *ppc; if ((addrlen != sizeof (struct sockaddr_in)) && (addrlen != sizeof (struct sockaddr_in6))) { /* invalid address */ GNUNET_break_op (0); asc (asc_cls, NULL); return; } ppc = GNUNET_malloc (sizeof (struct PrettyPrinterContext)); ppc->asc = asc; ppc->asc_cls = asc_cls; if (addrlen == sizeof (struct sockaddr_in)) { v4 = (const struct sockaddr_in *) addr; ppc->port = ntohs (v4->sin_port); } else { v6 = (const struct sockaddr_in6 *) addr; ppc->port = ntohs (v6->sin6_port); } GNUNET_RESOLVER_hostname_get (plugin->env->sched, plugin->env->cfg, addr, addrlen, !numeric, timeout, &append_port, ppc); } /** * Update the last-received and bandwidth quota values * for this session. * * @param session session to update * @param force set to GNUNET_YES if we should update even * though the minimum refresh time has not yet expired */ static void update_quota (struct Session *session, int force) { struct GNUNET_TIME_Absolute now; unsigned long long delta; unsigned long long total_allowed; unsigned long long total_remaining; now = GNUNET_TIME_absolute_get (); delta = now.value - session->last_quota_update.value; if ((delta < MIN_QUOTA_REFRESH_TIME) && (!force)) return; /* too early, not enough data */ total_allowed = session->quota_in * delta; if (total_allowed > session->last_received) { /* got less than acceptable */ total_remaining = total_allowed - session->last_received; session->last_received = 0; delta = total_remaining / session->quota_in; /* bonus seconds */ if (delta > MAX_BANDWIDTH_CARRY) delta = MAX_BANDWIDTH_CARRY; /* limit amount of carry-over */ } else { /* got more than acceptable */ total_remaining = 0; session->last_received -= total_allowed; delta = 0; } session->last_quota_update.value = now.value - delta; } /** * Set a quota for receiving data from the given peer; this is a * per-transport limit. The transport should limit its read/select * calls to stay below the quota (in terms of incoming data). * * @param cls closure * @param peer the peer for whom the quota is given * @param quota_in quota for receiving/sending data in bytes per ms */ static void tcp_plugin_set_receive_quota (void *cls, const struct GNUNET_PeerIdentity *target, uint32_t quota_in) { struct Plugin *plugin = cls; struct Session *session; session = find_session_by_target (plugin, target); if (session->quota_in != quota_in) { update_quota (session, GNUNET_YES); if (session->quota_in > quota_in) session->last_quota_update = GNUNET_TIME_absolute_get (); session->quota_in = quota_in; } } /** * Check if the given port is plausible (must be either * our listen port or our advertised port). If it is * neither, we return one of these two ports at random. * * @return either in_port or a more plausible port */ static uint16_t check_port (struct Plugin *plugin, uint16_t in_port) { if ((in_port == plugin->adv_port) || (in_port == plugin->open_port)) return in_port; return (GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK, 2) == 0) ? plugin->open_port : plugin->adv_port; } /** * Another peer has suggested an address for this * peer and transport plugin. Check that this could be a valid * address. If so, consider adding it to the list * of addresses. * * @param cls closure * @param addr pointer to the address * @param addrlen length of addr * @return GNUNET_OK if this is a plausible address for this peer * and transport */ static int tcp_plugin_address_suggested (void *cls, const void *addr, size_t addrlen) { struct Plugin *plugin = cls; char buf[sizeof (struct sockaddr_in6)]; struct sockaddr_in *v4; struct sockaddr_in6 *v6; char dst[INET6_ADDRSTRLEN]; uint16_t port; if ((addrlen != sizeof (struct sockaddr_in)) && (addrlen != sizeof (struct sockaddr_in6))) { GNUNET_break_op (0); return GNUNET_SYSERR; } memcpy (buf, addr, sizeof (struct sockaddr_in6)); if (addrlen == sizeof (struct sockaddr_in)) { v4 = (struct sockaddr_in *) buf; v4->sin_port = htons (check_port (plugin, ntohs (v4->sin_port))); inet_ntop (AF_INET, &v4->sin_addr, dst, sizeof (dst)); port = ntohs (v4->sin_port); } else { v6 = (struct sockaddr_in6 *) buf; v6->sin6_port = htons (check_port (plugin, ntohs (v6->sin6_port))); inet_ntop (AF_INET6, &v6->sin6_addr, dst, sizeof (dst)); port = ntohs (v6->sin6_port); } #if DEBUG_TCP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "Informing transport service about my address `%s:%u'.\n", dst, port); #endif plugin->env->notify_address (plugin->env->cls, "tcp", buf, addrlen, LEARNED_ADDRESS_EXPIRATION); return GNUNET_OK; } /** * We've received a welcome from this peer via TCP. * Possibly create a fresh client record and send back * our welcome. * * @param cls closure * @param client identification of the client * @param message the actual message */ static void handle_tcp_welcome (void *cls, struct GNUNET_SERVER_Client *client, const struct GNUNET_MessageHeader *message) { struct Plugin *plugin = cls; struct Session *session_c; const struct WelcomeMessage *wm; uint16_t msize; uint32_t addrlen; size_t alen; void *vaddr; const struct sockaddr *addr; #if DEBUG_TCP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "Received `%s' message from %p.\n", "WELCOME", client); #endif msize = ntohs (message->size); if (msize < sizeof (struct WelcomeMessage)) { GNUNET_break_op (0); GNUNET_SERVER_receive_done (client, GNUNET_SYSERR); return; } wm = (const struct WelcomeMessage *) message; session_c = find_session_by_client (plugin, client); if (session_c == NULL) { vaddr = NULL; GNUNET_SERVER_client_get_address (client, &vaddr, &alen); GNUNET_SERVER_client_keep (client); session_c = create_session (plugin, &wm->clientIdentity, client, vaddr, alen); #if DEBUG_TCP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "Creating new session %p for incoming `%s' message.\n", session_c, "WELCOME"); #endif GNUNET_free_non_null (vaddr); process_pending_messages (session_c); } session_c->expecting_welcome = GNUNET_NO; if (0 < (addrlen = msize - sizeof (struct WelcomeMessage))) { addr = (const struct sockaddr *) &wm[1]; tcp_plugin_address_suggested (plugin, addr, addrlen); } GNUNET_SERVER_receive_done (client, GNUNET_OK); } /** * Calculate how long we should delay reading from the TCP socket to * ensure that we stay within our bandwidth limits (push back). * * @param session for which client should this be calculated */ static struct GNUNET_TIME_Relative calculate_throttle_delay (struct Session *session) { struct GNUNET_TIME_Relative ret; struct GNUNET_TIME_Absolute now; uint64_t del; uint64_t avail; uint64_t excess; now = GNUNET_TIME_absolute_get (); del = now.value - session->last_quota_update.value; if (del > MAX_BANDWIDTH_CARRY) { update_quota (session, GNUNET_YES); del = now.value - session->last_quota_update.value; GNUNET_assert (del <= MAX_BANDWIDTH_CARRY); } if (session->quota_in == 0) session->quota_in = 1; /* avoid divison by zero */ avail = del * session->quota_in; if (avail > session->last_received) return GNUNET_TIME_UNIT_ZERO; /* can receive right now */ excess = session->last_received - avail; ret.value = excess / session->quota_in; return ret; } /** * Task to signal the server that we can continue * receiving from the TCP client now. */ static void delayed_done (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) { struct Session *session = cls; GNUNET_SERVER_receive_done (session->client, GNUNET_OK); } /** * We've received data for this peer via TCP. Unbox, * compute latency and forward. * * @param cls closure * @param client identification of the client * @param message the actual message */ static void handle_tcp_data (void *cls, struct GNUNET_SERVER_Client *client, const struct GNUNET_MessageHeader *message) { struct Plugin *plugin = cls; struct Session *session; const struct DataMessage *dm; uint16_t msize; const struct GNUNET_MessageHeader *msg; struct GNUNET_TIME_Relative latency; struct GNUNET_TIME_Absolute ttime; struct GNUNET_TIME_Absolute now; struct GNUNET_TIME_Relative delay; uint64_t ack_in; #if DEBUG_TCP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "Receiving data from other peer.\n"); #endif msize = ntohs (message->size); if ((msize < sizeof (struct DataMessage) + sizeof (struct GNUNET_MessageHeader))) { GNUNET_break_op (0); GNUNET_SERVER_receive_done (client, GNUNET_SYSERR); return; } session = find_session_by_client (plugin, client); if ((NULL == session) || (GNUNET_YES == session->expecting_welcome)) { GNUNET_break_op (0); GNUNET_SERVER_receive_done (client, GNUNET_SYSERR); return; } dm = (const struct DataMessage *) message; session->max_in_msg_counter = GNUNET_MAX (session->max_in_msg_counter, GNUNET_ntohll (dm->ack_out)); msg = (const struct GNUNET_MessageHeader *) &dm[1]; if (msize != sizeof (struct DataMessage) + ntohs (msg->size)) { GNUNET_break_op (0); GNUNET_SERVER_receive_done (client, GNUNET_SYSERR); return; } /* estimate latency */ ack_in = GNUNET_ntohll (dm->ack_in); if ((ack_in <= session->out_msg_counter) && (session->out_msg_counter - ack_in < ACK_LOG_SIZE)) { delay = GNUNET_TIME_relative_ntoh (dm->delay); ttime = session->gen_time[ack_in % ACK_LOG_SIZE]; now = GNUNET_TIME_absolute_get (); if (delay.value > now.value - ttime.value) delay.value = 0; /* not plausible */ /* update (round-trip) latency using ageing; we use 7:1 so that we can reasonably quickly react to changes, but not so fast that latency is largely jitter... */ session->latency_estimate = ((7 * session->latency_estimate) + (now.value - ttime.value - delay.value)) / 8; } latency.value = (uint64_t) session->latency_estimate; /* deliver on */ #if DEBUG_TCP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "Forwarding data of type %u to transport service.\n", ntohs (msg->type)); #endif session->service_context = plugin->env->receive (plugin->env->cls, session, session->service_context, latency, &session->target, msg); /* update bandwidth used */ session->last_received += msize; update_quota (session, GNUNET_NO); delay = calculate_throttle_delay (session); if (delay.value == 0) GNUNET_SERVER_receive_done (client, GNUNET_OK); else GNUNET_SCHEDULER_add_delayed (session->plugin->env->sched, GNUNET_NO, GNUNET_SCHEDULER_PRIORITY_HIGH, GNUNET_SCHEDULER_NO_PREREQUISITE_TASK, delay, &delayed_done, session); } /** * Handlers for the various TCP messages. */ static struct GNUNET_SERVER_MessageHandler my_handlers[] = { {&handle_tcp_welcome, NULL, GNUNET_MESSAGE_TYPE_TRANSPORT_TCP_WELCOME, 0}, {&handle_tcp_data, NULL, GNUNET_MESSAGE_TYPE_TRANSPORT_TCP_DATA, 0}, {NULL, NULL, 0, 0} }; static void create_tcp_handlers (struct Plugin *plugin) { unsigned int i; plugin->handlers = GNUNET_malloc (sizeof (my_handlers)); memcpy (plugin->handlers, my_handlers, sizeof (my_handlers)); for (i = 0; i < sizeof (my_handlers) / sizeof (struct GNUNET_SERVER_MessageHandler); i++) plugin->handlers[i].callback_cls = plugin; GNUNET_SERVER_add_handlers (plugin->server, plugin->handlers); } /** * Functions with this signature are called whenever a peer * is disconnected on the network level. * * @param cls closure * @param client identification of the client */ static void disconnect_notify (void *cls, struct GNUNET_SERVER_Client *client) { struct Plugin *plugin = cls; struct Session *session; #if DEBUG_TCP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "Notified about network-level disconnect of client %p.\n", client); #endif session = find_session_by_client (plugin, client); if (session == NULL) return; /* unknown, nothing to do */ #if DEBUG_TCP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "Will now destroy session %p.\n", session); #endif disconnect_session (session); } /** * Add the IP of our network interface to the list of * our external IP addresses. */ static int process_interfaces (void *cls, const char *name, int isDefault, const struct sockaddr *addr, socklen_t addrlen) { struct Plugin *plugin = cls; char dst[INET6_ADDRSTRLEN]; int af; struct sockaddr_in *v4; struct sockaddr_in6 *v6; af = addr->sa_family; if (af == AF_INET) { v4 = (struct sockaddr_in *) addr; inet_ntop (AF_INET, &v4->sin_addr, dst, sizeof (dst)); v4->sin_port = htons (plugin->adv_port); } else { GNUNET_assert (af == AF_INET6); v6 = (struct sockaddr_in6 *) addr; inet_ntop (AF_INET6, &v6->sin6_addr, dst, sizeof (dst)); v6->sin6_port = htons (plugin->adv_port); } GNUNET_log_from (GNUNET_ERROR_TYPE_INFO | GNUNET_ERROR_TYPE_BULK, "tcp", _("Found address `%s' (%s)\n"), dst, name); plugin->env->notify_address (plugin->env->cls, "tcp", addr, addrlen, GNUNET_TIME_UNIT_FOREVER_REL); return GNUNET_OK; } /** * Function called by the resolver for each address obtained from DNS * for our own hostname. Add the addresses to the list of our * external IP addresses. * * @param cls closure * @param addr one of the addresses of the host, NULL for the last address * @param addrlen length of the address */ static void process_hostname_ips (void *cls, const struct sockaddr *addr, socklen_t addrlen) { struct Plugin *plugin = cls; if (addr == NULL) return; plugin->env->notify_address (plugin->env->cls, "tcp", addr, addrlen, GNUNET_TIME_UNIT_FOREVER_REL); } /** * Entry point for the plugin. */ void * libgnunet_plugin_transport_tcp_init (void *cls) { struct GNUNET_TRANSPORT_PluginEnvironment *env = cls; struct GNUNET_TRANSPORT_PluginFunctions *api; struct Plugin *plugin; struct GNUNET_SERVICE_Context *service; unsigned long long aport; unsigned long long bport; service = GNUNET_SERVICE_start ("tcp", env->sched, env->cfg); if (service == NULL) { GNUNET_log_from (GNUNET_ERROR_TYPE_WARNING, "tcp", _ ("Failed to start service for `%s' transport plugin.\n"), "tcp"); return NULL; } aport = 0; if ((GNUNET_OK != GNUNET_CONFIGURATION_get_value_number (env->cfg, "tcp", "PORT", &bport)) || (bport > 65535) || ((GNUNET_OK == GNUNET_CONFIGURATION_get_value_number (env->cfg, "tcp", "ADVERTISED-PORT", &aport)) && (aport > 65535))) { GNUNET_log_from (GNUNET_ERROR_TYPE_ERROR, "tcp", _ ("Require valid port number for service `%s' in configuration!\n"), "tcp"); GNUNET_SERVICE_stop (service); return NULL; } if (aport == 0) aport = bport; plugin = GNUNET_malloc (sizeof (struct Plugin)); plugin->open_port = bport; plugin->adv_port = aport; plugin->env = env; plugin->lsock = NULL; plugin->statistics = NULL; api = GNUNET_malloc (sizeof (struct GNUNET_TRANSPORT_PluginFunctions)); api->cls = plugin; api->send_to = &tcp_plugin_send_to; api->send = &tcp_plugin_send; api->cancel = &tcp_plugin_cancel; api->address_pretty_printer = &tcp_plugin_address_pretty_printer; api->set_receive_quota = &tcp_plugin_set_receive_quota; api->address_suggested = &tcp_plugin_address_suggested; api->cost_estimate = 42; /* TODO: ATS */ plugin->service = service; plugin->server = GNUNET_SERVICE_get_server (service); create_tcp_handlers (plugin); GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "tcp", _("TCP transport listening on port %u\n"), bport); if (aport != bport) GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "tcp", _ ("TCP transport advertises itself as being on port %u\n"), aport); GNUNET_SERVER_disconnect_notify (plugin->server, &disconnect_notify, plugin); GNUNET_OS_network_interfaces_list (&process_interfaces, plugin); GNUNET_RESOLVER_hostname_resolve (env->sched, env->cfg, AF_UNSPEC, HOSTNAME_RESOLVE_TIMEOUT, &process_hostname_ips, plugin); return api; } /** * Exit point from the plugin. */ void * libgnunet_plugin_transport_tcp_done (void *cls) { struct GNUNET_TRANSPORT_PluginFunctions *api = cls; struct Plugin *plugin = api->cls; GNUNET_SERVICE_stop (plugin->service); GNUNET_free (plugin->handlers); GNUNET_free (plugin); GNUNET_free (api); return NULL; } /* end of plugin_transport_tcp.c */