/* This file is part of GNUnet (C) 2002--2012 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. */ /** * @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_constants.h" #include "gnunet_connection_lib.h" #include "gnunet_container_lib.h" #include "gnunet_nat_lib.h" #include "gnunet_os_lib.h" #include "gnunet_protocols.h" #include "gnunet_resolver_service.h" #include "gnunet_server_lib.h" #include "gnunet_service_lib.h" #include "gnunet_signatures.h" #include "gnunet_statistics_service.h" #include "gnunet_transport_service.h" #include "gnunet_transport_plugin.h" #include "transport.h" #define LOG(kind,...) GNUNET_log_from (kind, "transport-tcp",__VA_ARGS__) /** * How long until we give up on establishing an NAT connection? * Must be > 4 RTT */ #define NAT_TIMEOUT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 10) GNUNET_NETWORK_STRUCT_BEGIN /** * Initial handshake message for a session. */ struct WelcomeMessage { /** * Type is GNUNET_MESSAGE_TYPE_TRANSPORT_TCP_WELCOME. */ struct GNUNET_MessageHeader header; /** * Identity of the node connecting (TCP client) */ struct GNUNET_PeerIdentity clientIdentity; }; /** * Basically a WELCOME message, but with the purpose * of giving the waiting peer a client handle to use */ struct TCP_NAT_ProbeMessage { /** * Type is GNUNET_MESSAGE_TYPE_TRANSPORT_TCP_NAT_PROBE. */ struct GNUNET_MessageHeader header; /** * Identity of the sender of the message. */ struct GNUNET_PeerIdentity clientIdentity; }; GNUNET_NETWORK_STRUCT_END /** * Context for sending a NAT probe via TCP. */ struct TCPProbeContext { /** * Active probes are kept in a DLL. */ struct TCPProbeContext *next; /** * Active probes are kept in a DLL. */ struct TCPProbeContext *prev; /** * Probe connection. */ struct GNUNET_CONNECTION_Handle *sock; /** * Message to be sent. */ struct TCP_NAT_ProbeMessage message; /** * Handle to the transmission. */ struct GNUNET_CONNECTION_TransmitHandle *transmit_handle; /** * Transport plugin handle. */ struct Plugin *plugin; }; GNUNET_NETWORK_STRUCT_BEGIN /** * Network format for IPv4 addresses. */ struct IPv4TcpAddress { /** * IPv4 address, in network byte order. */ uint32_t ipv4_addr GNUNET_PACKED; /** * Port number, in network byte order. */ uint16_t t4_port GNUNET_PACKED; }; /** * Network format for IPv6 addresses. */ struct IPv6TcpAddress { /** * IPv6 address. */ struct in6_addr ipv6_addr GNUNET_PACKED; /** * Port number, in network byte order. */ uint16_t t6_port GNUNET_PACKED; }; GNUNET_NETWORK_STRUCT_END /** * 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 doubly-linked list. */ struct PendingMessage *next; /** * This is a doubly-linked list. */ struct PendingMessage *prev; /** * The pending message */ const char *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; /** * So that the gnunet-service-transport can group messages together, * these pending messages need to accept a message buffer and size * instead of just a GNUNET_MessageHeader. */ size_t message_size; }; /** * Session handle for TCP connections. */ struct Session { /** * To whom are we talking to (set to our identity * if we are still waiting for the welcome message) */ struct GNUNET_PeerIdentity target; /** * API requirement. */ struct SessionHeader header; /** * Pointer to the global plugin struct. */ struct Plugin *plugin; /** * The client (used to identify this connection) */ struct GNUNET_SERVER_Client *client; /** * Task cleaning up a NAT client connection establishment attempt; */ GNUNET_SCHEDULER_TaskIdentifier nat_connection_timeout; /** * Messages currently pending for transmission * to this peer, if any. */ struct PendingMessage *pending_messages_head; /** * Messages currently pending for transmission * to this peer, if any. */ struct PendingMessage *pending_messages_tail; /** * Handle for pending transmission request. */ struct GNUNET_SERVER_TransmitHandle *transmit_handle; /** * ID of task used to delay receiving more to throttle sender. */ GNUNET_SCHEDULER_TaskIdentifier receive_delay_task; /** * Session timeout task */ GNUNET_SCHEDULER_TaskIdentifier timeout_task; /** * Address of the other peer (either based on our 'connect' * call or on our 'accept' call). * * struct IPv4TcpAddress or struct IPv6TcpAddress * */ void *addr; /** * Length of connect_addr. */ size_t addrlen; /** * Last activity on this connection. Used to select preferred * connection. */ struct GNUNET_TIME_Absolute last_activity; /** * Are we still expecting the welcome message? (GNUNET_YES/GNUNET_NO) */ int expecting_welcome; /** * Was this a connection that was inbound (we accepted)? (GNUNET_YES/GNUNET_NO) */ int inbound; /** * Was this session created using NAT traversal? */ int is_nat; /** * ATS network type in NBO */ uint32_t ats_address_network_type; }; /** * Encapsulation of all of the state of the plugin. */ struct Plugin { /** * Our environment. */ struct GNUNET_TRANSPORT_PluginEnvironment *env; /** * The listen socket. */ struct GNUNET_CONNECTION_Handle *lsock; /** * Our handle to the NAT module. */ struct GNUNET_NAT_Handle *nat; /** * Map from peer identities to sessions for the given peer. */ struct GNUNET_CONTAINER_MultiHashMap *sessionmap; /** * 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; /** * Map of peers we have tried to contact behind a NAT */ struct GNUNET_CONTAINER_MultiHashMap *nat_wait_conns; /** * List of active TCP probes. */ struct TCPProbeContext *probe_head; /** * List of active TCP probes. */ struct TCPProbeContext *probe_tail; /** * Handle for (DYN)DNS lookup of our external IP. */ struct GNUNET_RESOLVER_RequestHandle *ext_dns; /** * How many more TCP sessions are we allowed to open right now? */ unsigned long long max_connections; /** * 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; }; /** * Start session timeout */ static void start_session_timeout (struct Session *s); /** * Increment session timeout due to activity */ static void reschedule_session_timeout (struct Session *s); /** * Cancel timeout */ static void stop_session_timeout (struct Session *s); /* DEBUG CODE */ static const char * tcp_address_to_string (void *cls, const void *addr, size_t addrlen); static unsigned int sessions; static void inc_sessions (struct Plugin *plugin, struct Session *session, int line) { sessions++; unsigned int size = GNUNET_CONTAINER_multihashmap_size(plugin->sessionmap); if (sessions != size) LOG (GNUNET_ERROR_TYPE_DEBUG, "Inconsistent sessions %u <-> session map size: %u\n", sessions, size); LOG (GNUNET_ERROR_TYPE_DEBUG, "%4i Session increased to %u (session map size: %u): `%s' `%s'\n", line, sessions, size, GNUNET_i2s (&session->target), tcp_address_to_string (NULL, session->addr, session->addrlen)); } static void dec_sessions (struct Plugin *plugin, struct Session *session, int line) { GNUNET_assert (sessions > 0); unsigned int size = GNUNET_CONTAINER_multihashmap_size(plugin->sessionmap); sessions--; if (sessions != size) LOG (GNUNET_ERROR_TYPE_DEBUG, "Inconsistent sessions %u <-> session map size: %u\n", sessions, size); LOG (GNUNET_ERROR_TYPE_DEBUG, "%4i Session decreased to %u (session map size: %u): `%s' `%s'\n", line, sessions, size, GNUNET_i2s (&session->target), tcp_address_to_string (NULL, session->addr, session->addrlen)); } /* DEBUG CODE */ /** * Function to check if an inbound connection is acceptable. * Mostly used to limit the total number of open connections * we can have. * * @param cls the 'struct Plugin' * @param ucred credentials, if available, otherwise NULL * @param addr address * @param addrlen length of address * @return GNUNET_YES to allow, GNUNET_NO to deny, GNUNET_SYSERR * for unknown address family (will be denied). */ static int plugin_tcp_access_check (void *cls, const struct GNUNET_CONNECTION_Credentials *ucred, const struct sockaddr *addr, socklen_t addrlen) { struct Plugin *plugin = cls; LOG (GNUNET_ERROR_TYPE_ERROR, "Accepting new incoming TCP connection from `%s'\n", GNUNET_a2s (addr, addrlen)); if (0 == plugin->max_connections) return GNUNET_NO; plugin->max_connections--; return GNUNET_YES; } /** * Our external IP address/port mapping has changed. * * @param cls closure, the 'struct LocalAddrList' * @param add_remove GNUNET_YES to mean the new public IP address, GNUNET_NO to mean * the previous (now invalid) one * @param addr either the previous or the new public IP address * @param addrlen actual lenght of the address */ static void tcp_nat_port_map_callback (void *cls, int add_remove, const struct sockaddr *addr, socklen_t addrlen) { struct Plugin *plugin = cls; struct IPv4TcpAddress t4; struct IPv6TcpAddress t6; void *arg; size_t args; LOG (GNUNET_ERROR_TYPE_DEBUG, "NPMC called with %d for address `%s'\n", add_remove, GNUNET_a2s (addr, addrlen)); /* convert 'addr' to our internal format */ switch (addr->sa_family) { case AF_INET: GNUNET_assert (addrlen == sizeof (struct sockaddr_in)); t4.ipv4_addr = ((struct sockaddr_in *) addr)->sin_addr.s_addr; t4.t4_port = ((struct sockaddr_in *) addr)->sin_port; arg = &t4; args = sizeof (t4); break; case AF_INET6: GNUNET_assert (addrlen == sizeof (struct sockaddr_in6)); memcpy (&t6.ipv6_addr, &((struct sockaddr_in6 *) addr)->sin6_addr, sizeof (struct in6_addr)); t6.t6_port = ((struct sockaddr_in6 *) addr)->sin6_port; arg = &t6; args = sizeof (t6); break; default: GNUNET_break (0); return; } /* modify our published address list */ plugin->env->notify_address (plugin->env->cls, add_remove, arg, args, "tcp"); } /** * Function called for a quick conversion of the binary address to * a numeric address. Note that the caller must not free the * address and that the next call to this function is allowed * to override the address again. * * @param cls closure ('struct Plugin*') * @param addr binary address * @param addrlen length of the address * @return string representing the same address */ static const char * tcp_address_to_string (void *cls, const void *addr, size_t addrlen) { static char rbuf[INET6_ADDRSTRLEN + 12]; char buf[INET6_ADDRSTRLEN]; const void *sb; struct in_addr a4; struct in6_addr a6; const struct IPv4TcpAddress *t4; const struct IPv6TcpAddress *t6; int af; uint16_t port; switch (addrlen) { case sizeof (struct IPv6TcpAddress): t6 = addr; af = AF_INET6; port = ntohs (t6->t6_port); memcpy (&a6, &t6->ipv6_addr, sizeof (a6)); sb = &a6; break; case sizeof (struct IPv4TcpAddress): t4 = addr; af = AF_INET; port = ntohs (t4->t4_port); memcpy (&a4, &t4->ipv4_addr, sizeof (a4)); sb = &a4; break; default: LOG (GNUNET_ERROR_TYPE_ERROR, _("Unexpected address length: %u bytes\n"), (unsigned int) addrlen); GNUNET_break (0); return NULL; } if (NULL == inet_ntop (af, sb, buf, INET6_ADDRSTRLEN)) { GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING, "inet_ntop"); return NULL; } GNUNET_snprintf (rbuf, sizeof (rbuf), (af == AF_INET6) ? "[%s]:%u" : "%s:%u", buf, port); return rbuf; } /** * Function called to convert a string address to * a binary address. * * @param cls closure ('struct Plugin*') * @param addr string address * @param addrlen length of the address * @param buf location to store the buffer * @param added location to store the number of bytes in the buffer. * If the function returns GNUNET_SYSERR, its contents are undefined. * @return GNUNET_OK on success, GNUNET_SYSERR on failure */ static int tcp_string_to_address (void *cls, const char *addr, uint16_t addrlen, void **buf, size_t *added) { struct sockaddr_storage socket_address; if ((NULL == addr) || (addrlen == 0)) { GNUNET_break (0); return GNUNET_SYSERR; } if ('\0' != addr[addrlen - 1]) { GNUNET_break (0); return GNUNET_SYSERR; } if (strlen (addr) != addrlen - 1) { GNUNET_break (0); return GNUNET_SYSERR; } if (GNUNET_OK != GNUNET_STRINGS_to_address_ip (addr, strlen (addr), &socket_address)) { GNUNET_break (0); return GNUNET_SYSERR; } switch (socket_address.ss_family) { case AF_INET: { struct IPv4TcpAddress *t4; struct sockaddr_in *in4 = (struct sockaddr_in *) &socket_address; t4 = GNUNET_malloc (sizeof (struct IPv4TcpAddress)); t4->ipv4_addr = in4->sin_addr.s_addr; t4->t4_port = in4->sin_port; *buf = t4; *added = sizeof (struct IPv4TcpAddress); return GNUNET_OK; } case AF_INET6: { struct IPv6TcpAddress *t6; struct sockaddr_in6 *in6 = (struct sockaddr_in6 *) &socket_address; t6 = GNUNET_malloc (sizeof (struct IPv6TcpAddress)); t6->ipv6_addr = in6->sin6_addr; t6->t6_port = in6->sin6_port; *buf = t6; *added = sizeof (struct IPv6TcpAddress); return GNUNET_OK; } default: return GNUNET_SYSERR; } } struct SessionClientCtx { const struct GNUNET_SERVER_Client *client; struct Session *ret; }; static int session_lookup_by_client_it (void *cls, const struct GNUNET_HashCode * key, void *value) { struct SessionClientCtx *sc_ctx = cls; struct Session *s = value; if (s->client == sc_ctx->client) { sc_ctx->ret = s; return GNUNET_NO; } return GNUNET_YES; } /** * Find the session handle for the given client. * * @param plugin the plugin * @param client which client to find the session handle for * @return NULL if no matching session exists */ static struct Session * lookup_session_by_client (struct Plugin *plugin, const struct GNUNET_SERVER_Client *client) { struct SessionClientCtx sc_ctx; sc_ctx.client = client; sc_ctx.ret = NULL; GNUNET_CONTAINER_multihashmap_iterate (plugin->sessionmap, &session_lookup_by_client_it, &sc_ctx); return sc_ctx.ret; } /** * Create a new session. Also queues a welcome message. * * @param plugin the plugin * @param target peer to connect to * @param client client to use, reference counter must have already been increased * @param is_nat this a NAT session, we should wait for a client to * connect to us from an address, then assign that to * the session * @return new session object */ static struct Session * create_session (struct Plugin *plugin, const struct GNUNET_PeerIdentity *target, struct GNUNET_SERVER_Client *client, int is_nat) { struct Session *session; struct PendingMessage *pm; struct WelcomeMessage welcome; if (GNUNET_YES != is_nat) GNUNET_assert (NULL != client); else GNUNET_assert (NULL == client); LOG (GNUNET_ERROR_TYPE_DEBUG, "Creating new session for peer `%4s'\n", GNUNET_i2s (target)); session = GNUNET_malloc (sizeof (struct Session)); session->last_activity = GNUNET_TIME_absolute_get (); session->plugin = plugin; session->is_nat = is_nat; session->client = client; session->target = *target; session->expecting_welcome = GNUNET_YES; session->ats_address_network_type = htonl (GNUNET_ATS_NET_UNSPECIFIED); pm = GNUNET_malloc (sizeof (struct PendingMessage) + sizeof (struct WelcomeMessage)); pm->msg = (const char *) &pm[1]; pm->message_size = sizeof (struct WelcomeMessage); welcome.header.size = htons (sizeof (struct WelcomeMessage)); welcome.header.type = htons (GNUNET_MESSAGE_TYPE_TRANSPORT_TCP_WELCOME); welcome.clientIdentity = *plugin->env->my_identity; memcpy (&pm[1], &welcome, sizeof (welcome)); pm->timeout = GNUNET_TIME_UNIT_FOREVER_ABS; GNUNET_STATISTICS_update (plugin->env->stats, gettext_noop ("# bytes currently in TCP buffers"), pm->message_size, GNUNET_NO); GNUNET_CONTAINER_DLL_insert (session->pending_messages_head, session->pending_messages_tail, pm); if (GNUNET_YES != is_nat) { GNUNET_STATISTICS_update (plugin->env->stats, gettext_noop ("# TCP sessions active"), 1, GNUNET_NO); } start_session_timeout (session); 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 * being 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 GNUNET_PeerIdentity pid; struct Plugin *plugin; struct PendingMessage *pos; struct PendingMessage *hd; struct PendingMessage *tl; struct GNUNET_TIME_Absolute now; char *cbuf; size_t ret; GNUNET_assert (NULL != session); session->transmit_handle = NULL; plugin = session->plugin; if (NULL == buf) { LOG (GNUNET_ERROR_TYPE_DEBUG, "Timeout trying to transmit to peer `%4s', discarding message queue.\n", GNUNET_i2s (&session->target)); /* timeout; cancel all messages that have already expired */ hd = NULL; tl = NULL; ret = 0; now = GNUNET_TIME_absolute_get (); while ((NULL != (pos = session->pending_messages_head)) && (pos->timeout.abs_value <= now.abs_value)) { GNUNET_CONTAINER_DLL_remove (session->pending_messages_head, session->pending_messages_tail, pos); LOG (GNUNET_ERROR_TYPE_DEBUG, "Failed to transmit %u byte message to `%4s'.\n", pos->message_size, GNUNET_i2s (&session->target)); ret += pos->message_size; GNUNET_CONTAINER_DLL_insert_after (hd, tl, tl, pos); } /* do this call before callbacks (so that if callbacks destroy * session, they have a chance to cancel actions done by this * call) */ process_pending_messages (session); pid = session->target; /* no do callbacks and do not use session again since * the callbacks may abort the session */ while (NULL != (pos = hd)) { GNUNET_CONTAINER_DLL_remove (hd, tl, pos); if (pos->transmit_cont != NULL) pos->transmit_cont (pos->transmit_cont_cls, &pid, GNUNET_SYSERR); GNUNET_free (pos); } GNUNET_STATISTICS_update (plugin->env->stats, gettext_noop ("# bytes currently in TCP buffers"), -(int64_t) ret, GNUNET_NO); GNUNET_STATISTICS_update (plugin->env->stats, gettext_noop ("# bytes discarded by TCP (timeout)"), ret, GNUNET_NO); return 0; } /* copy all pending messages that would fit */ ret = 0; cbuf = buf; hd = NULL; tl = NULL; while (NULL != (pos = session->pending_messages_head)) { if (ret + pos->message_size > size) break; GNUNET_CONTAINER_DLL_remove (session->pending_messages_head, session->pending_messages_tail, pos); GNUNET_assert (size >= pos->message_size); LOG (GNUNET_ERROR_TYPE_DEBUG, "Transmitting message of type %u\n", ntohs (((struct GNUNET_MessageHeader *) pos->msg)->type)); /* FIXME: this memcpy can be up to 7% of our total runtime */ memcpy (cbuf, pos->msg, pos->message_size); cbuf += pos->message_size; ret += pos->message_size; size -= pos->message_size; GNUNET_CONTAINER_DLL_insert_tail (hd, tl, pos); } /* schedule 'continuation' before callbacks so that callbacks that * cancel everything don't cause us to use a session that no longer * exists... */ process_pending_messages (session); session->last_activity = GNUNET_TIME_absolute_get (); pid = session->target; /* we'll now call callbacks that may cancel the session; hence * we should not use 'session' after this point */ while (NULL != (pos = hd)) { GNUNET_CONTAINER_DLL_remove (hd, tl, pos); if (pos->transmit_cont != NULL) pos->transmit_cont (pos->transmit_cont_cls, &pid, GNUNET_OK); GNUNET_free (pos); } GNUNET_assert (hd == NULL); GNUNET_assert (tl == NULL); LOG (GNUNET_ERROR_TYPE_DEBUG, "Transmitting %u bytes\n", ret); GNUNET_STATISTICS_update (plugin->env->stats, gettext_noop ("# bytes currently in TCP buffers"), -(int64_t) ret, GNUNET_NO); GNUNET_STATISTICS_update (plugin->env->stats, gettext_noop ("# bytes transmitted via TCP"), ret, GNUNET_NO); 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) { struct PendingMessage *pm; GNUNET_assert (session->client != NULL); if (session->transmit_handle != NULL) return; if (NULL == (pm = session->pending_messages_head)) return; session->transmit_handle = GNUNET_SERVER_notify_transmit_ready (session->client, pm->message_size, GNUNET_TIME_absolute_get_remaining (pm->timeout), &do_transmit, 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 PendingMessage *pm; struct Plugin * plugin = session->plugin; LOG (GNUNET_ERROR_TYPE_DEBUG, "Disconnecting session of peer `%s' address `%s'\n", GNUNET_i2s (&session->target), tcp_address_to_string (NULL, session->addr, session->addrlen)); stop_session_timeout (session); if (GNUNET_YES == GNUNET_CONTAINER_multihashmap_remove (plugin->sessionmap, &session->target.hashPubKey, session)) { GNUNET_STATISTICS_update (session->plugin->env->stats, gettext_noop ("# TCP sessions active"), -1, GNUNET_NO); dec_sessions (plugin, session, __LINE__); } else GNUNET_assert (GNUNET_YES == GNUNET_CONTAINER_multihashmap_remove (plugin->nat_wait_conns, &session->target.hashPubKey, session)); /* clean up state */ if (session->transmit_handle != NULL) { GNUNET_SERVER_notify_transmit_ready_cancel (session->transmit_handle); session->transmit_handle = NULL; } session->plugin->env->session_end (session->plugin->env->cls, &session->target, session); if (GNUNET_SCHEDULER_NO_TASK != session->nat_connection_timeout) { GNUNET_SCHEDULER_cancel (session->nat_connection_timeout); session->nat_connection_timeout = GNUNET_SCHEDULER_NO_TASK; } while (NULL != (pm = session->pending_messages_head)) { LOG (GNUNET_ERROR_TYPE_DEBUG, pm->transmit_cont != NULL ? "Could not deliver message to `%4s'.\n" : "Could not deliver message to `%4s', notifying.\n", GNUNET_i2s (&session->target)); GNUNET_STATISTICS_update (session->plugin->env->stats, gettext_noop ("# bytes currently in TCP buffers"), -(int64_t) pm->message_size, GNUNET_NO); GNUNET_STATISTICS_update (session->plugin->env->stats, gettext_noop ("# bytes discarded by TCP (disconnect)"), pm->message_size, GNUNET_NO); GNUNET_CONTAINER_DLL_remove (session->pending_messages_head, session->pending_messages_tail, pm); if (NULL != pm->transmit_cont) pm->transmit_cont (pm->transmit_cont_cls, &session->target, GNUNET_SYSERR); GNUNET_free (pm); } if (session->receive_delay_task != GNUNET_SCHEDULER_NO_TASK) { GNUNET_SCHEDULER_cancel (session->receive_delay_task); if (NULL != session->client) GNUNET_SERVER_receive_done (session->client, GNUNET_SYSERR); } if (NULL != session->client) { GNUNET_SERVER_client_disconnect (session->client); GNUNET_SERVER_client_drop (session->client); session->client = NULL; } GNUNET_free_non_null (session->addr); GNUNET_assert (NULL == session->transmit_handle); GNUNET_free (session); } /* FIXME WORKAROUND FOR MANTIS 0002445 */ struct result { struct Session *s; int res; }; int session_it (void *cls, const struct GNUNET_HashCode * key, void *value) { struct result *res = cls; if (res->s == value) { res->res = GNUNET_OK; return GNUNET_NO; } else { return GNUNET_YES; } } /* FIXME END WORKAROUND FOR MANTIS 0002445 */ /** * Function that can be used by the transport service to transmit * a message using the plugin. Note that in the case of a * peer disconnecting, the continuation MUST be called * prior to the disconnect notification itself. This function * will be called with this peer's HELLO message to initiate * a fresh connection to another peer. * * @param cls closure * @param session which session must be used * @param msgbuf the message to transmit * @param msgbuf_size number of bytes in 'msgbuf' * @param priority how important is the message (most plugins will * ignore message priority and just FIFO) * @param to how long to wait at most for the transmission (does not * require plugins to discard the message after the timeout, * just advisory for the desired delay; most plugins will ignore * this as well) * @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...); can be NULL * @param cont_cls closure for cont * @return number of bytes used (on the physical network, with overheads); * -1 on hard errors (i.e. address invalid); 0 is a legal value * and does NOT mean that the message was not transmitted (DV) */ static ssize_t tcp_plugin_send (void *cls, struct Session *session, const char *msgbuf, size_t msgbuf_size, unsigned int priority, struct GNUNET_TIME_Relative to, GNUNET_TRANSPORT_TransmitContinuation cont, void *cont_cls) { struct Plugin * plugin = cls; struct PendingMessage *pm; GNUNET_assert (NULL != plugin); GNUNET_assert (NULL != session); /* FIXME WORKAROUND FOR MANTIS 0002445 */ struct result res1; struct result res2; res1.s = session; res1.res = GNUNET_SYSERR; GNUNET_CONTAINER_multihashmap_iterate (plugin->sessionmap, &session_it, &res1); res2.s = session; res2.res = GNUNET_SYSERR; GNUNET_CONTAINER_multihashmap_iterate (plugin->sessionmap, &session_it, &res2); if ((res1.res == GNUNET_SYSERR) && (res2.res == GNUNET_SYSERR)) { LOG (GNUNET_ERROR_TYPE_ERROR, "WORKAROUND MANTIS BUG 2445: This Trying to send to invalid session %p\n", session); GNUNET_break (0); return GNUNET_SYSERR; } /* FIXME END WORKAROUND FOR MANTIS 0002445 */ /* create new message entry */ pm = GNUNET_malloc (sizeof (struct PendingMessage) + msgbuf_size); pm->msg = (const char *) &pm[1]; memcpy (&pm[1], msgbuf, msgbuf_size); pm->message_size = msgbuf_size; pm->timeout = GNUNET_TIME_relative_to_absolute (to); pm->transmit_cont = cont; pm->transmit_cont_cls = cont_cls; LOG (GNUNET_ERROR_TYPE_DEBUG, "Asked to transmit %u bytes to `%s', added message to list.\n", msgbuf_size, GNUNET_i2s (&session->target)); if (GNUNET_YES == GNUNET_CONTAINER_multihashmap_contains_value (plugin->sessionmap, &session->target.hashPubKey, session)) { GNUNET_assert (session->client != NULL); reschedule_session_timeout (session); GNUNET_SERVER_client_set_timeout (session->client, GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT); GNUNET_STATISTICS_update (plugin->env->stats, gettext_noop ("# bytes currently in TCP buffers"), msgbuf_size, GNUNET_NO); /* append pm to pending_messages list */ GNUNET_CONTAINER_DLL_insert_tail (session->pending_messages_head, session->pending_messages_tail, pm); process_pending_messages (session); return msgbuf_size; } else if (GNUNET_YES == GNUNET_CONTAINER_multihashmap_contains_value(plugin->nat_wait_conns, &session->target.hashPubKey, session)) { LOG (GNUNET_ERROR_TYPE_DEBUG, "This NAT WAIT session for peer `%s' is not yet ready!\n", GNUNET_i2s (&session->target)); reschedule_session_timeout (session); GNUNET_STATISTICS_update (plugin->env->stats, gettext_noop ("# bytes currently in TCP buffers"), msgbuf_size, GNUNET_NO); /* append pm to pending_messages list */ GNUNET_CONTAINER_DLL_insert_tail (session->pending_messages_head, session->pending_messages_tail, pm); return msgbuf_size; } else { LOG (GNUNET_ERROR_TYPE_ERROR, "Invalid session %p\n", session); if (NULL != cont) cont (cont_cls, &session->target, GNUNET_SYSERR); GNUNET_break (0); GNUNET_free (pm); return GNUNET_SYSERR; /* session does not exist here */ } } struct SessionItCtx { void *addr; size_t addrlen; struct Session *result; }; static int session_lookup_it (void *cls, const struct GNUNET_HashCode *key, void *value) { struct SessionItCtx * si_ctx = cls; struct Session * session = value; #if 0 char * a1 = strdup (tcp_address_to_string(NULL, session->addr, session->addrlen)); char * a2 = strdup (tcp_address_to_string(NULL, si_ctx->addr, si_ctx->addrlen)); LOG (GNUNET_ERROR_TYPE_DEBUG, "Comparing: %s %u <-> %s %u\n", a1, session->addrlen, a2, si_ctx->addrlen); GNUNET_free (a1); GNUNET_free (a2); #endif if (session->addrlen != si_ctx->addrlen) { return GNUNET_YES; } if (0 != memcmp (session->addr, si_ctx->addr, si_ctx->addrlen)) { return GNUNET_YES; } #if 0 a1 = strdup (tcp_address_to_string(NULL, session->addr, session->addrlen)); a2 = strdup (tcp_address_to_string(NULL, si_ctx->addr, si_ctx->addrlen)); LOG (GNUNET_ERROR_TYPE_DEBUG, "Comparing: %s %u <-> %s %u , OK!\n", a1, session->addrlen, a2, si_ctx->addrlen); GNUNET_free (a1); GNUNET_free (a2); #endif /* Found existing session */ si_ctx->result = session; return GNUNET_NO; } /** * Task cleaning up a NAT connection attempt after timeout */ static void nat_connect_timeout (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) { struct Session *session = cls; LOG (GNUNET_ERROR_TYPE_DEBUG, "NAT WAIT connection to `%4s' at `%s' could not be established, removing session\n", GNUNET_i2s (&session->target), tcp_address_to_string(NULL, session->addr, session->addrlen)); disconnect_session (session); } /** * Create a new session to transmit data to the target * This session will used to send data to this peer and the plugin will * notify us by calling the env->session_end function * * @param cls closure * @param address pointer to the GNUNET_HELLO_Address * @return the session if the address is valid, NULL otherwise */ static struct Session * tcp_plugin_get_session (void *cls, const struct GNUNET_HELLO_Address *address) { struct Plugin *plugin = cls; struct Session *session = NULL; int af; const void *sb; size_t sbs; struct GNUNET_CONNECTION_Handle *sa; struct sockaddr_in a4; struct sockaddr_in6 a6; const struct IPv4TcpAddress *t4; const struct IPv6TcpAddress *t6; struct GNUNET_ATS_Information ats; unsigned int is_natd = GNUNET_NO; size_t addrlen; GNUNET_assert (plugin != NULL); GNUNET_assert (address != NULL); addrlen = address->address_length; LOG (GNUNET_ERROR_TYPE_DEBUG, "Trying to get session for `%s' address of peer `%s'\n", tcp_address_to_string(NULL, address->address, address->address_length), GNUNET_i2s (&address->peer)); /* look for existing session */ if (GNUNET_YES == GNUNET_CONTAINER_multihashmap_contains (plugin->sessionmap, &address->peer.hashPubKey)) { struct SessionItCtx si_ctx; si_ctx.addr = (void *) address->address; si_ctx.addrlen = address->address_length; si_ctx.result = NULL; GNUNET_CONTAINER_multihashmap_get_multiple (plugin->sessionmap, &address->peer.hashPubKey, &session_lookup_it, &si_ctx); if (si_ctx.result != NULL) { session = si_ctx.result; LOG (GNUNET_ERROR_TYPE_DEBUG, "Found exisiting session for `%s' address `%s' session %p\n", GNUNET_i2s (&address->peer), tcp_address_to_string(NULL, address->address, address->address_length), session); return session; } LOG (GNUNET_ERROR_TYPE_DEBUG, "Existing sessions did not match address `%s' or peer `%s'\n", tcp_address_to_string(NULL, address->address, address->address_length), GNUNET_i2s (&address->peer)); } if (addrlen == sizeof (struct IPv6TcpAddress)) { GNUNET_assert (NULL != address->address); /* make static analysis happy */ t6 = address->address; af = AF_INET6; memset (&a6, 0, sizeof (a6)); #if HAVE_SOCKADDR_IN_SIN_LEN a6.sin6_len = sizeof (a6); #endif a6.sin6_family = AF_INET6; a6.sin6_port = t6->t6_port; if (t6->t6_port == 0) is_natd = GNUNET_YES; memcpy (&a6.sin6_addr, &t6->ipv6_addr, sizeof (struct in6_addr)); sb = &a6; sbs = sizeof (a6); } else if (addrlen == sizeof (struct IPv4TcpAddress)) { GNUNET_assert (NULL != address->address); /* make static analysis happy */ t4 = address->address; af = AF_INET; memset (&a4, 0, sizeof (a4)); #if HAVE_SOCKADDR_IN_SIN_LEN a4.sin_len = sizeof (a4); #endif a4.sin_family = AF_INET; a4.sin_port = t4->t4_port; if (t4->t4_port == 0) is_natd = GNUNET_YES; a4.sin_addr.s_addr = t4->ipv4_addr; sb = &a4; sbs = sizeof (a4); } else { LOG (GNUNET_ERROR_TYPE_ERROR, _("Address of unexpected length: %u\n"), addrlen); GNUNET_break (0); return NULL; } ats = plugin->env->get_address_type (plugin->env->cls, sb ,sbs); if ((is_natd == GNUNET_YES) && (addrlen == sizeof (struct IPv6TcpAddress))) { /* NAT client only works with IPv4 addresses */ return NULL; } if (0 == plugin->max_connections) { /* saturated */ return NULL; } if ((is_natd == GNUNET_YES) && (GNUNET_YES == GNUNET_CONTAINER_multihashmap_contains (plugin->nat_wait_conns, &address->peer.hashPubKey))) { /* Only do one NAT punch attempt per peer identity */ return NULL; } if ((is_natd == GNUNET_YES) && (NULL != plugin->nat) && (GNUNET_NO == GNUNET_CONTAINER_multihashmap_contains (plugin->nat_wait_conns, &address->peer.hashPubKey))) { LOG (GNUNET_ERROR_TYPE_DEBUG, "Found valid IPv4 NAT address (creating session)!\n") ; session = create_session (plugin, &address->peer, NULL, GNUNET_YES); session->addrlen = 0; session->addr = NULL; session->ats_address_network_type = ats.value; session->nat_connection_timeout = GNUNET_SCHEDULER_add_delayed (NAT_TIMEOUT, &nat_connect_timeout, session); GNUNET_assert (session != NULL); GNUNET_assert (GNUNET_OK == GNUNET_CONTAINER_multihashmap_put (plugin->nat_wait_conns, &session->target.hashPubKey, session, GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY)); LOG (GNUNET_ERROR_TYPE_DEBUG, "Created NAT WAIT connection to `%4s' at `%s'\n", GNUNET_i2s (&session->target), GNUNET_a2s (sb, sbs)); if (GNUNET_OK == GNUNET_NAT_run_client (plugin->nat, &a4)) return session; else { LOG (GNUNET_ERROR_TYPE_DEBUG, "Running NAT client for `%4s' at `%s' failed\n", GNUNET_i2s (&session->target), GNUNET_a2s (sb, sbs)); disconnect_session (session); return NULL; } } /* create new outbound session */ GNUNET_assert (0 != plugin->max_connections); sa = GNUNET_CONNECTION_create_from_sockaddr (af, sb, sbs); if (sa == NULL) { LOG (GNUNET_ERROR_TYPE_DEBUG, "Failed to create connection to `%4s' at `%s'\n", GNUNET_i2s (&address->peer), GNUNET_a2s (sb, sbs)); return NULL; } plugin->max_connections--; LOG (GNUNET_ERROR_TYPE_DEBUG, "Asked to transmit to `%4s', creating fresh session using address `%s'.\n", GNUNET_i2s (&address->peer), GNUNET_a2s (sb, sbs)); session = create_session (plugin, &address->peer, GNUNET_SERVER_connect_socket (plugin->server, sa), GNUNET_NO); session->addr = GNUNET_malloc (addrlen); memcpy (session->addr, address->address, addrlen); session->addrlen = addrlen; session->ats_address_network_type = ats.value; GNUNET_CONTAINER_multihashmap_put (plugin->sessionmap, &session->target.hashPubKey, session, GNUNET_CONTAINER_MULTIHASHMAPOPTION_MULTIPLE); inc_sessions (plugin, session, __LINE__); LOG (GNUNET_ERROR_TYPE_DEBUG, "Creating new session for `%s' address `%s' session %p\n", GNUNET_i2s (&address->peer), tcp_address_to_string(NULL, address->address, address->address_length), session); /* Send TCP Welcome */ process_pending_messages (session); return session; } static int session_disconnect_it (void *cls, const struct GNUNET_HashCode * key, void *value) { struct Session *session = value; GNUNET_STATISTICS_update (session->plugin->env->stats, gettext_noop ("# transport-service disconnect requests for TCP"), 1, GNUNET_NO); disconnect_session (session); return GNUNET_YES; } /** * 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 target peer for which the last transmission is * to be cancelled */ static void tcp_plugin_disconnect (void *cls, const struct GNUNET_PeerIdentity *target) { struct Plugin *plugin = cls; LOG (GNUNET_ERROR_TYPE_DEBUG, "Disconnecting peer `%4s'\n", GNUNET_i2s (target)); GNUNET_CONTAINER_multihashmap_get_multiple (plugin->sessionmap, &target->hashPubKey, &session_disconnect_it, plugin); GNUNET_CONTAINER_multihashmap_get_multiple (plugin->nat_wait_conns, &target->hashPubKey, &session_disconnect_it, plugin); } /** * Context for address to string conversion. */ struct PrettyPrinterContext { /** * Function to call with the result. */ GNUNET_TRANSPORT_AddressStringCallback asc; /** * Clsoure for 'asc'. */ void *asc_cls; /** * Port to add after the IP address. */ uint16_t port; int ipv6; }; /** * Append our port and forward the result. * * @param cls the 'struct PrettyPrinterContext*' * @param hostname hostname part of the address */ 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; } if (GNUNET_YES == ppc->ipv6) GNUNET_asprintf (&ret, "[%s]:%d", hostname, ppc->port); else 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 type 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 PrettyPrinterContext *ppc; const void *sb; size_t sbs; struct sockaddr_in a4; struct sockaddr_in6 a6; const struct IPv4TcpAddress *t4; const struct IPv6TcpAddress *t6; uint16_t port; if (addrlen == sizeof (struct IPv6TcpAddress)) { t6 = addr; memset (&a6, 0, sizeof (a6)); a6.sin6_family = AF_INET6; a6.sin6_port = t6->t6_port; memcpy (&a6.sin6_addr, &t6->ipv6_addr, sizeof (struct in6_addr)); port = ntohs (t6->t6_port); sb = &a6; sbs = sizeof (a6); } else if (addrlen == sizeof (struct IPv4TcpAddress)) { t4 = addr; memset (&a4, 0, sizeof (a4)); a4.sin_family = AF_INET; a4.sin_port = t4->t4_port; a4.sin_addr.s_addr = t4->ipv4_addr; port = ntohs (t4->t4_port); sb = &a4; sbs = sizeof (a4); } else if (0 == addrlen) { asc (asc_cls, ""); asc (asc_cls, NULL); return; } else { /* invalid address */ GNUNET_break_op (0); asc (asc_cls, NULL); return; } ppc = GNUNET_malloc (sizeof (struct PrettyPrinterContext)); if (addrlen == sizeof (struct IPv6TcpAddress)) ppc->ipv6 = GNUNET_YES; else ppc->ipv6 = GNUNET_NO; ppc->asc = asc; ppc->asc_cls = asc_cls; ppc->port = port; GNUNET_RESOLVER_hostname_get (sb, sbs, !numeric, timeout, &append_port, ppc); } /** * Check if the given port is plausible (must be either our listen * port or our advertised port), or any port if we are behind NAT * and do not have a port open. If it is neither, we return * GNUNET_SYSERR. * * @param plugin global variables * @param in_port port number to check * @return GNUNET_OK if port is either open_port or adv_port */ static int check_port (struct Plugin *plugin, uint16_t in_port) { if ((in_port == plugin->adv_port) || (in_port == plugin->open_port)) return GNUNET_OK; return GNUNET_SYSERR; } /** * Function that will be called to check if a binary address for this * plugin is well-formed and corresponds to an address for THIS peer * (as per our configuration). Naturally, if absolutely necessary, * plugins can be a bit conservative in their answer, but in general * plugins should make sure that the address does not redirect * traffic to a 3rd party that might try to man-in-the-middle our * traffic. * * @param cls closure, our 'struct Plugin*' * @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, GNUNET_SYSERR if not */ static int tcp_plugin_check_address (void *cls, const void *addr, size_t addrlen) { struct Plugin *plugin = cls; struct IPv4TcpAddress *v4; struct IPv6TcpAddress *v6; if ((addrlen != sizeof (struct IPv4TcpAddress)) && (addrlen != sizeof (struct IPv6TcpAddress))) { GNUNET_break_op (0); return GNUNET_SYSERR; } if (addrlen == sizeof (struct IPv4TcpAddress)) { v4 = (struct IPv4TcpAddress *) addr; if (GNUNET_OK != check_port (plugin, ntohs (v4->t4_port))) return GNUNET_SYSERR; if (GNUNET_OK != GNUNET_NAT_test_address (plugin->nat, &v4->ipv4_addr, sizeof (struct in_addr))) return GNUNET_SYSERR; } else { v6 = (struct IPv6TcpAddress *) addr; if (IN6_IS_ADDR_LINKLOCAL (&v6->ipv6_addr)) { GNUNET_break_op (0); return GNUNET_SYSERR; } if (GNUNET_OK != check_port (plugin, ntohs (v6->t6_port))) return GNUNET_SYSERR; if (GNUNET_OK != GNUNET_NAT_test_address (plugin->nat, &v6->ipv6_addr, sizeof (struct in6_addr))) return GNUNET_SYSERR; } return GNUNET_OK; } /** * We've received a nat probe from this peer via TCP. Finish * creating the client session and resume sending of queued * messages. * * @param cls closure * @param client identification of the client * @param message the actual message */ static void handle_tcp_nat_probe (void *cls, struct GNUNET_SERVER_Client *client, const struct GNUNET_MessageHeader *message) { struct Plugin *plugin = cls; struct Session *session; const struct TCP_NAT_ProbeMessage *tcp_nat_probe; size_t alen; void *vaddr; struct IPv4TcpAddress *t4; struct IPv6TcpAddress *t6; const struct sockaddr_in *s4; const struct sockaddr_in6 *s6; LOG (GNUNET_ERROR_TYPE_DEBUG, "Received NAT probe\n"); /* We have received a TCP NAT probe, meaning we (hopefully) initiated * a connection to this peer by running gnunet-nat-client. This peer * received the punch message and now wants us to use the new connection * as the default for that peer. Do so and then send a WELCOME message * so we can really be connected! */ if (ntohs (message->size) != sizeof (struct TCP_NAT_ProbeMessage)) { GNUNET_break_op (0); GNUNET_SERVER_receive_done (client, GNUNET_SYSERR); return; } tcp_nat_probe = (const struct TCP_NAT_ProbeMessage *) message; if (0 == memcmp (&tcp_nat_probe->clientIdentity, plugin->env->my_identity, sizeof (struct GNUNET_PeerIdentity))) { /* refuse connections from ourselves */ GNUNET_SERVER_receive_done (client, GNUNET_SYSERR); return; } session = GNUNET_CONTAINER_multihashmap_get (plugin->nat_wait_conns, &tcp_nat_probe-> clientIdentity.hashPubKey); if (session == NULL) { LOG (GNUNET_ERROR_TYPE_DEBUG, "Did NOT find session for NAT probe!\n"); GNUNET_SERVER_receive_done (client, GNUNET_OK); return; } LOG (GNUNET_ERROR_TYPE_DEBUG, "Found session for NAT probe!\n"); if (session->nat_connection_timeout != GNUNET_SCHEDULER_NO_TASK) { GNUNET_SCHEDULER_cancel (session->nat_connection_timeout); session->nat_connection_timeout = GNUNET_SCHEDULER_NO_TASK; } if (GNUNET_OK != GNUNET_SERVER_client_get_address (client, &vaddr, &alen)) { GNUNET_break (0); GNUNET_SERVER_receive_done (client, GNUNET_SYSERR); disconnect_session (session); return; } GNUNET_assert (GNUNET_CONTAINER_multihashmap_remove (plugin->nat_wait_conns, &tcp_nat_probe->clientIdentity.hashPubKey, session) == GNUNET_YES); GNUNET_CONTAINER_multihashmap_put (plugin->sessionmap, &session->target.hashPubKey, session, GNUNET_CONTAINER_MULTIHASHMAPOPTION_MULTIPLE); session->last_activity = GNUNET_TIME_absolute_get (); session->inbound = GNUNET_NO; LOG (GNUNET_ERROR_TYPE_DEBUG, "Found address `%s' for incoming connection\n", GNUNET_a2s (vaddr, alen)); switch (((const struct sockaddr *) vaddr)->sa_family) { case AF_INET: s4 = vaddr; t4 = GNUNET_malloc (sizeof (struct IPv4TcpAddress)); t4->t4_port = s4->sin_port; t4->ipv4_addr = s4->sin_addr.s_addr; session->addr = t4; session->addrlen = sizeof (struct IPv4TcpAddress); break; case AF_INET6: s6 = vaddr; t6 = GNUNET_malloc (sizeof (struct IPv6TcpAddress)); t6->t6_port = s6->sin6_port; memcpy (&t6->ipv6_addr, &s6->sin6_addr, sizeof (struct in6_addr)); session->addr = t6; session->addrlen = sizeof (struct IPv6TcpAddress); break; default: GNUNET_break_op (0); LOG (GNUNET_ERROR_TYPE_DEBUG, "Bad address for incoming connection!\n"); GNUNET_free (vaddr); GNUNET_SERVER_receive_done (client, GNUNET_SYSERR); disconnect_session (session); return; } GNUNET_free (vaddr); GNUNET_break (NULL == session->client); GNUNET_SERVER_client_keep (client); session->client = client; inc_sessions (plugin, session, __LINE__); GNUNET_STATISTICS_update (plugin->env->stats, gettext_noop ("# TCP sessions active"), 1, GNUNET_NO); process_pending_messages (session); GNUNET_SERVER_receive_done (client, 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; const struct WelcomeMessage *wm = (const struct WelcomeMessage *) message; struct Session *session; size_t alen; void *vaddr; struct IPv4TcpAddress *t4; struct IPv6TcpAddress *t6; const struct sockaddr_in *s4; const struct sockaddr_in6 *s6; if (0 == memcmp (&wm->clientIdentity, plugin->env->my_identity, sizeof (struct GNUNET_PeerIdentity))) { /* refuse connections from ourselves */ GNUNET_SERVER_receive_done (client, GNUNET_SYSERR); return; } LOG (GNUNET_ERROR_TYPE_DEBUG, "Received %s message from `%4s'\n", "WELCOME", GNUNET_i2s (&wm->clientIdentity)); GNUNET_STATISTICS_update (plugin->env->stats, gettext_noop ("# TCP WELCOME messages received"), 1, GNUNET_NO); session = lookup_session_by_client (plugin, client); if (session != NULL) { if (GNUNET_OK == GNUNET_SERVER_client_get_address (client, &vaddr, &alen)) { LOG (GNUNET_ERROR_TYPE_DEBUG, "Found existing session %p for peer `%s'\n", session, GNUNET_a2s (vaddr, alen)); GNUNET_free (vaddr); } } else { GNUNET_SERVER_client_keep (client); session = create_session (plugin, &wm->clientIdentity, client, GNUNET_NO); session->inbound = GNUNET_YES; if (GNUNET_OK == GNUNET_SERVER_client_get_address (client, &vaddr, &alen)) { if (alen == sizeof (struct sockaddr_in)) { s4 = vaddr; t4 = GNUNET_malloc (sizeof (struct IPv4TcpAddress)); t4->t4_port = s4->sin_port; t4->ipv4_addr = s4->sin_addr.s_addr; session->addr = t4; session->addrlen = sizeof (struct IPv4TcpAddress); } else if (alen == sizeof (struct sockaddr_in6)) { s6 = vaddr; t6 = GNUNET_malloc (sizeof (struct IPv6TcpAddress)); t6->t6_port = s6->sin6_port; memcpy (&t6->ipv6_addr, &s6->sin6_addr, sizeof (struct in6_addr)); session->addr = t6; session->addrlen = sizeof (struct IPv6TcpAddress); } struct GNUNET_ATS_Information ats; ats = plugin->env->get_address_type (plugin->env->cls, vaddr ,alen); session->ats_address_network_type = ats.value; GNUNET_free (vaddr); } else { LOG (GNUNET_ERROR_TYPE_DEBUG, "Did not obtain TCP socket address for incoming connection\n"); } GNUNET_CONTAINER_multihashmap_put (plugin->sessionmap, &session->target.hashPubKey, session, GNUNET_CONTAINER_MULTIHASHMAPOPTION_MULTIPLE); inc_sessions (plugin, session, __LINE__); } if (session->expecting_welcome != GNUNET_YES) { GNUNET_break_op (0); GNUNET_SERVER_receive_done (client, GNUNET_SYSERR); return; } session->last_activity = GNUNET_TIME_absolute_get (); session->expecting_welcome = GNUNET_NO; process_pending_messages (session); GNUNET_SERVER_client_set_timeout (client, GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT); GNUNET_SERVER_receive_done (client, GNUNET_OK); } /** * Task to signal the server that we can continue * receiving from the TCP client now. * * @param cls the 'struct Session*' * @param tc task context (unused) */ static void delayed_done (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) { struct Session *session = cls; struct GNUNET_TIME_Relative delay; struct GNUNET_ATS_Information ats; session->receive_delay_task = GNUNET_SCHEDULER_NO_TASK; delay = session->plugin->env->receive (session->plugin->env->cls, &session->target, NULL, &ats, 0, session, NULL, 0); reschedule_session_timeout (session); if (delay.rel_value == 0) GNUNET_SERVER_receive_done (session->client, GNUNET_OK); else session->receive_delay_task = GNUNET_SCHEDULER_add_delayed (delay, &delayed_done, session); } /** * 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; struct GNUNET_TIME_Relative delay; uint16_t type; type = ntohs (message->type); if ((GNUNET_MESSAGE_TYPE_TRANSPORT_TCP_WELCOME == type) || (GNUNET_MESSAGE_TYPE_TRANSPORT_TCP_NAT_PROBE == type)) { /* We don't want to propagate WELCOME and NAT Probe messages up! */ GNUNET_SERVER_receive_done (client, GNUNET_OK); return; } session = lookup_session_by_client (plugin, client); if (NULL == session) { /* No inbound session found */ void *vaddr; size_t alen; GNUNET_SERVER_client_get_address (client, &vaddr, &alen); LOG (GNUNET_ERROR_TYPE_ERROR, "Received unexpected %u bytes of type %u from `%s'\n", (unsigned int) ntohs (message->size), (unsigned int) ntohs (message->type), GNUNET_a2s(vaddr, alen)); GNUNET_break_op (0); GNUNET_SERVER_receive_done (client, GNUNET_SYSERR); GNUNET_free_non_null(vaddr); return; } else if (GNUNET_YES == session->expecting_welcome) { /* Session is expecting WELCOME message */ void *vaddr; size_t alen; GNUNET_SERVER_client_get_address (client, &vaddr, &alen); LOG (GNUNET_ERROR_TYPE_ERROR, "Received unexpected %u bytes of type %u from `%s'\n", (unsigned int) ntohs (message->size), (unsigned int) ntohs (message->type), GNUNET_a2s(vaddr, alen)); GNUNET_break_op (0); GNUNET_SERVER_receive_done (client, GNUNET_SYSERR); GNUNET_free_non_null(vaddr); return; } session->last_activity = GNUNET_TIME_absolute_get (); LOG (GNUNET_ERROR_TYPE_DEBUG, "Passing %u bytes of type %u from `%4s' to transport service.\n", (unsigned int) ntohs (message->size), (unsigned int) ntohs (message->type), GNUNET_i2s (&session->target)); GNUNET_STATISTICS_update (plugin->env->stats, gettext_noop ("# bytes received via TCP"), ntohs (message->size), GNUNET_NO); struct GNUNET_ATS_Information distance[2]; distance[0].type = htonl (GNUNET_ATS_QUALITY_NET_DISTANCE); distance[0].value = htonl (1); distance[1].type = htonl (GNUNET_ATS_NETWORK_TYPE); distance[1].value = session->ats_address_network_type; GNUNET_break (ntohl(session->ats_address_network_type) != GNUNET_ATS_NET_UNSPECIFIED); GNUNET_assert (GNUNET_CONTAINER_multihashmap_contains_value (plugin->sessionmap, &session->target.hashPubKey, session)); delay = plugin->env->receive (plugin->env->cls, &session->target, message, (const struct GNUNET_ATS_Information *) &distance, 1, session, (GNUNET_YES == session->inbound) ? NULL : session->addr, (GNUNET_YES == session->inbound) ? 0 : session->addrlen); reschedule_session_timeout (session); if (delay.rel_value == 0) { GNUNET_SERVER_receive_done (client, GNUNET_OK); } else { LOG (GNUNET_ERROR_TYPE_DEBUG, "Throttling receiving from `%s' for %llu ms\n", GNUNET_i2s (&session->target), (unsigned long long) delay.rel_value); GNUNET_SERVER_disable_receive_done_warning (client); session->receive_delay_task = GNUNET_SCHEDULER_add_delayed (delay, &delayed_done, session); } } /** * 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 (client == NULL) return; plugin->max_connections++; session = lookup_session_by_client (plugin, client); if (session == NULL) return; /* unknown, nothing to do */ LOG (GNUNET_ERROR_TYPE_DEBUG, "Destroying session of `%4s' with %s due to network-level disconnect.\n", GNUNET_i2s (&session->target), (session->addr != NULL) ? tcp_address_to_string (session->plugin, session->addr, session->addrlen) : "*"); GNUNET_STATISTICS_update (session->plugin->env->stats, gettext_noop ("# network-level TCP disconnect events"), 1, GNUNET_NO); disconnect_session (session); } /** * We can now send a probe message, copy into buffer to really send. * * @param cls closure, a struct TCPProbeContext * @param size max size to copy * @param buf buffer to copy message to * @return number of bytes copied into buf */ static size_t notify_send_probe (void *cls, size_t size, void *buf) { struct TCPProbeContext *tcp_probe_ctx = cls; struct Plugin *plugin = tcp_probe_ctx->plugin; size_t ret; tcp_probe_ctx->transmit_handle = NULL; GNUNET_CONTAINER_DLL_remove (plugin->probe_head, plugin->probe_tail, tcp_probe_ctx); if (buf == NULL) { GNUNET_CONNECTION_destroy (tcp_probe_ctx->sock); GNUNET_free (tcp_probe_ctx); return 0; } GNUNET_assert (size >= sizeof (tcp_probe_ctx->message)); memcpy (buf, &tcp_probe_ctx->message, sizeof (tcp_probe_ctx->message)); GNUNET_SERVER_connect_socket (tcp_probe_ctx->plugin->server, tcp_probe_ctx->sock); ret = sizeof (tcp_probe_ctx->message); GNUNET_free (tcp_probe_ctx); return ret; } /** * Function called by the NAT subsystem suggesting another peer wants * to connect to us via connection reversal. Try to connect back to the * given IP. * * @param cls closure * @param addr address to try * @param addrlen number of bytes in addr */ static void try_connection_reversal (void *cls, const struct sockaddr *addr, socklen_t addrlen) { struct Plugin *plugin = cls; struct GNUNET_CONNECTION_Handle *sock; struct TCPProbeContext *tcp_probe_ctx; /** * We have received an ICMP response, ostensibly from a peer * that wants to connect to us! Send a message to establish a connection. */ sock = GNUNET_CONNECTION_create_from_sockaddr (AF_INET, addr, addrlen); if (sock == NULL) { /* failed for some odd reason (out of sockets?); ignore attempt */ return; } /* FIXME: do we need to track these probe context objects so that * we can clean them up on plugin unload? */ tcp_probe_ctx = GNUNET_malloc (sizeof (struct TCPProbeContext)); tcp_probe_ctx->message.header.size = htons (sizeof (struct TCP_NAT_ProbeMessage)); tcp_probe_ctx->message.header.type = htons (GNUNET_MESSAGE_TYPE_TRANSPORT_TCP_NAT_PROBE); memcpy (&tcp_probe_ctx->message.clientIdentity, plugin->env->my_identity, sizeof (struct GNUNET_PeerIdentity)); tcp_probe_ctx->plugin = plugin; tcp_probe_ctx->sock = sock; GNUNET_CONTAINER_DLL_insert (plugin->probe_head, plugin->probe_tail, tcp_probe_ctx); tcp_probe_ctx->transmit_handle = GNUNET_CONNECTION_notify_transmit_ready (sock, ntohs (tcp_probe_ctx-> message.header.size), GNUNET_TIME_UNIT_FOREVER_REL, ¬ify_send_probe, tcp_probe_ctx); } /** * Session was idle, so disconnect it */ static void session_timeout (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) { GNUNET_assert (NULL != cls); struct Session *s = cls; s->timeout_task = GNUNET_SCHEDULER_NO_TASK; GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Session %p was idle for %llu ms, disconnecting\n", s, (unsigned long long) GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT.rel_value); /* call session destroy function */ disconnect_session(s); } /** * Start session timeout */ static void start_session_timeout (struct Session *s) { GNUNET_assert (NULL != s); GNUNET_assert (GNUNET_SCHEDULER_NO_TASK == s->timeout_task); s->timeout_task = GNUNET_SCHEDULER_add_delayed (GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT, &session_timeout, s); GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Timeout for session %p set to %llu ms\n", s, (unsigned long long) GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT.rel_value); } /** * Increment session timeout due to activity */ static void reschedule_session_timeout (struct Session *s) { GNUNET_assert (NULL != s); GNUNET_assert (GNUNET_SCHEDULER_NO_TASK != s->timeout_task); GNUNET_SCHEDULER_cancel (s->timeout_task); s->timeout_task = GNUNET_SCHEDULER_add_delayed (GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT, &session_timeout, s); GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Timeout rescheduled for session %p set to %llu ms\n", s, (unsigned long long) GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT.rel_value); } /** * Cancel timeout */ static void stop_session_timeout (struct Session *s) { GNUNET_assert (NULL != s); if (GNUNET_SCHEDULER_NO_TASK != s->timeout_task) { GNUNET_SCHEDULER_cancel (s->timeout_task); s->timeout_task = GNUNET_SCHEDULER_NO_TASK; GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Timeout stopped for session %p canceled\n", s, (unsigned long long) GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT.rel_value); } } /** * Entry point for the plugin. * * @param cls closure, the 'struct GNUNET_TRANSPORT_PluginEnvironment*' * @return the 'struct GNUNET_TRANSPORT_PluginFunctions*' or NULL on error */ void * libgnunet_plugin_transport_tcp_init (void *cls) { static const struct GNUNET_SERVER_MessageHandler my_handlers[] = { {&handle_tcp_welcome, NULL, GNUNET_MESSAGE_TYPE_TRANSPORT_TCP_WELCOME, sizeof (struct WelcomeMessage)}, {&handle_tcp_nat_probe, NULL, GNUNET_MESSAGE_TYPE_TRANSPORT_TCP_NAT_PROBE, sizeof (struct TCP_NAT_ProbeMessage)}, {&handle_tcp_data, NULL, GNUNET_MESSAGE_TYPE_ALL, 0}, {NULL, NULL, 0, 0} }; 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; unsigned long long max_connections; unsigned int i; struct GNUNET_TIME_Relative idle_timeout; int ret; struct sockaddr **addrs; socklen_t *addrlens; if (NULL == env->receive) { /* run in 'stub' mode (i.e. as part of gnunet-peerinfo), don't fully initialze the plugin or the API */ api = GNUNET_malloc (sizeof (struct GNUNET_TRANSPORT_PluginFunctions)); api->cls = NULL; api->address_pretty_printer = &tcp_plugin_address_pretty_printer; api->address_to_string = &tcp_address_to_string; api->string_to_address = &tcp_string_to_address; return api; } if (GNUNET_OK != GNUNET_CONFIGURATION_get_value_number (env->cfg, "transport-tcp", "MAX_CONNECTIONS", &max_connections)) max_connections = 128; aport = 0; if ((GNUNET_OK != GNUNET_CONFIGURATION_get_value_number (env->cfg, "transport-tcp", "PORT", &bport)) || (bport > 65535) || ((GNUNET_OK == GNUNET_CONFIGURATION_get_value_number (env->cfg, "transport-tcp", "ADVERTISED-PORT", &aport)) && (aport > 65535))) { LOG (GNUNET_ERROR_TYPE_ERROR, _ ("Require valid port number for service `%s' in configuration!\n"), "transport-tcp"); return NULL; } if (aport == 0) aport = bport; if (bport == 0) aport = 0; if (bport != 0) { service = GNUNET_SERVICE_start ("transport-tcp", env->cfg, GNUNET_SERVICE_OPTION_NONE); if (service == NULL) { LOG (GNUNET_ERROR_TYPE_WARNING, _("Failed to start service.\n")); return NULL; } } else service = NULL; plugin = GNUNET_malloc (sizeof (struct Plugin)); plugin->sessionmap = GNUNET_CONTAINER_multihashmap_create (max_connections, GNUNET_YES); plugin->max_connections = max_connections; plugin->open_port = bport; plugin->adv_port = aport; plugin->env = env; plugin->lsock = NULL; if ((service != NULL) && (GNUNET_SYSERR != (ret = GNUNET_SERVICE_get_server_addresses ("transport-tcp", env->cfg, &addrs, &addrlens)))) { plugin->nat = GNUNET_NAT_register (env->cfg, GNUNET_YES, aport, (unsigned int) ret, (const struct sockaddr **) addrs, addrlens, &tcp_nat_port_map_callback, &try_connection_reversal, plugin); while (ret > 0) { ret--; GNUNET_assert (addrs[ret] != NULL); GNUNET_free (addrs[ret]); } GNUNET_free_non_null (addrs); GNUNET_free_non_null (addrlens); } else { plugin->nat = GNUNET_NAT_register (env->cfg, GNUNET_YES, 0, 0, NULL, NULL, NULL, &try_connection_reversal, plugin); } api = GNUNET_malloc (sizeof (struct GNUNET_TRANSPORT_PluginFunctions)); api->cls = plugin; api->send = &tcp_plugin_send; api->get_session = &tcp_plugin_get_session; api->disconnect = &tcp_plugin_disconnect; api->address_pretty_printer = &tcp_plugin_address_pretty_printer; api->check_address = &tcp_plugin_check_address; api->address_to_string = &tcp_address_to_string; api->string_to_address = &tcp_string_to_address; plugin->service = service; if (service != NULL) { plugin->server = GNUNET_SERVICE_get_server (service); } else { if (GNUNET_OK != GNUNET_CONFIGURATION_get_value_time (env->cfg, "transport-tcp", "TIMEOUT", &idle_timeout)) { GNUNET_log_config_missing (GNUNET_ERROR_TYPE_ERROR, "transport-tcp", "TIMEOUT"); if (plugin->nat != NULL) GNUNET_NAT_unregister (plugin->nat); GNUNET_free (plugin); GNUNET_free (api); return NULL; } plugin->server = GNUNET_SERVER_create_with_sockets (&plugin_tcp_access_check, plugin, NULL, idle_timeout, GNUNET_YES); } 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); GNUNET_SERVER_disconnect_notify (plugin->server, &disconnect_notify, plugin); plugin->nat_wait_conns = GNUNET_CONTAINER_multihashmap_create (16, GNUNET_YES); if (bport != 0) LOG (GNUNET_ERROR_TYPE_INFO, _("TCP transport listening on port %llu\n"), bport); else LOG (GNUNET_ERROR_TYPE_INFO, _ ("TCP transport not listening on any port (client only)\n")); if (aport != bport) LOG (GNUNET_ERROR_TYPE_INFO, _ ("TCP transport advertises itself as being on port %llu\n"), aport); /* Initially set connections to 0 */ GNUNET_STATISTICS_set(plugin->env->stats, gettext_noop ("# TCP sessions active"), 0, GNUNET_NO); 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; struct TCPProbeContext *tcp_probe; if (NULL == plugin) { GNUNET_free (api); return NULL; } LOG (GNUNET_ERROR_TYPE_DEBUG, "Shutting down TCP plugin\n"); /* Removing leftover sessions */ GNUNET_CONTAINER_multihashmap_iterate(plugin->sessionmap, &session_disconnect_it, NULL); /* Removing leftover NAT sessions */ GNUNET_CONTAINER_multihashmap_iterate(plugin->nat_wait_conns, &session_disconnect_it, NULL); if (plugin->service != NULL) GNUNET_SERVICE_stop (plugin->service); else GNUNET_SERVER_destroy (plugin->server); GNUNET_free (plugin->handlers); if (plugin->nat != NULL) GNUNET_NAT_unregister (plugin->nat); while (NULL != (tcp_probe = plugin->probe_head)) { GNUNET_CONTAINER_DLL_remove (plugin->probe_head, plugin->probe_tail, tcp_probe); GNUNET_CONNECTION_destroy (tcp_probe->sock); GNUNET_free (tcp_probe); } GNUNET_CONTAINER_multihashmap_destroy (plugin->nat_wait_conns); GNUNET_CONTAINER_multihashmap_destroy (plugin->sessionmap); GNUNET_free (plugin); GNUNET_free (api); return NULL; } /* end of plugin_transport_tcp.c */