/* This file is part of GNUnet (C) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 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 DEBUG_TCP GNUNET_EXTRA_LOGGING #define DEBUG_TCP_NAT GNUNET_EXTRA_LOGGING /** * 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; }; /** * 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; }; /** * 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; }; /** * 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 { /** * API requirement. */ struct SessionHeader header; /** * 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; /** * 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_CONNECTION_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; /** * ID of task used to delay receiving more to throttle sender. */ GNUNET_SCHEDULER_TaskIdentifier receive_delay_task; /** * Address of the other peer (either based on our 'connect' * call or on our 'accept' call). */ void *connect_addr; /** * Last activity on this connection. Used to select preferred * connection. */ struct GNUNET_TIME_Absolute last_activity; /** * Length of connect_addr. */ size_t connect_alen; /** * 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; }; /** * 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; /** * List of open TCP sessions. */ struct Session *sessions; /** * 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; }; /** * 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; 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; GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "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); } /** * 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; if (addrlen == sizeof (struct IPv6TcpAddress)) { t6 = addr; af = AF_INET6; port = ntohs (t6->t6_port); memcpy (&a6, &t6->ipv6_addr, sizeof (a6)); sb = &a6; } else if (addrlen == sizeof (struct IPv4TcpAddress)) { t4 = addr; af = AF_INET; port = ntohs (t4->t4_port); memcpy (&a4, &t4->ipv4_addr, sizeof (a4)); sb = &a4; } else { GNUNET_log_from (GNUNET_ERROR_TYPE_ERROR, "tcp", _("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; } /** * 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 * 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 new session. Also queues a welcome message. * * @param plugin the plugin * @param target peer to connect to * @param client client to use * @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 *ret; struct PendingMessage *pm; struct WelcomeMessage welcome; if (is_nat != GNUNET_YES) GNUNET_assert (client != NULL); else GNUNET_assert (client == NULL); #if DEBUG_TCP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "Creating new session for peer `%4s'\n", GNUNET_i2s (target)); #endif ret = GNUNET_malloc (sizeof (struct Session)); ret->last_activity = GNUNET_TIME_absolute_get (); ret->plugin = plugin; ret->is_nat = is_nat; if (is_nat != GNUNET_YES) /* If not a NAT WAIT conn, add it to global list */ { ret->next = plugin->sessions; plugin->sessions = ret; } ret->client = client; ret->target = *target; ret->expecting_welcome = GNUNET_YES; 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 (ret->pending_messages_head, ret->pending_messages_tail, pm); if (is_nat != GNUNET_YES) GNUNET_STATISTICS_update (plugin->env->stats, gettext_noop ("# TCP sessions active"), 1, 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); /** * 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 (session != NULL); session->transmit_handle = NULL; plugin = session->plugin; if (buf == NULL) { #if DEBUG_TCP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "Timeout trying to transmit to peer `%4s', discarding message queue.\n", GNUNET_i2s (&session->target)); #endif /* 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); #if DEBUG_TCP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "Failed to transmit %u byte message to `%4s'.\n", pos->message_size, GNUNET_i2s (&session->target)); #endif 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); /* 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_after (hd, tl, 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); #if DEBUG_TCP > 1 GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "Transmitting %u bytes\n", ret); #endif 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 Session *prev; struct Session *pos; struct PendingMessage *pm; #if DEBUG_TCP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "Disconnecting from `%4s' at %s.\n", GNUNET_i2s (&session->target), (session->connect_addr != NULL) ? tcp_address_to_string (session->plugin, session->connect_addr, session->connect_alen) : "*"); #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->transmit_handle != NULL) { GNUNET_CONNECTION_notify_transmit_ready_cancel (session->transmit_handle); session->transmit_handle = NULL; } session->plugin->env->session_end (session->plugin->env->cls, &session->target, session); while (NULL != (pm = session->pending_messages_head)) { #if DEBUG_TCP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", pm->transmit_cont != NULL ? "Could not deliver message to `%4s'.\n" : "Could not deliver message to `%4s', notifying.\n", GNUNET_i2s (&session->target)); #endif 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); } GNUNET_break (session->client != NULL); if (session->receive_delay_task != GNUNET_SCHEDULER_NO_TASK) { GNUNET_SCHEDULER_cancel (session->receive_delay_task); if (session->client != NULL) GNUNET_SERVER_receive_done (session->client, GNUNET_SYSERR); } if (session->client != NULL) { GNUNET_SERVER_client_drop (session->client); session->client = NULL; } GNUNET_STATISTICS_update (session->plugin->env->stats, gettext_noop ("# TCP sessions active"), -1, GNUNET_NO); GNUNET_free_non_null (session->connect_addr); GNUNET_assert (NULL == session->transmit_handle); GNUNET_free (session); } /** * Given two otherwise equivalent sessions, pick the better one. * * @param s1 one session (also default) * @param s2 other session * @return "better" session (more active) */ static struct Session * select_better_session (struct Session *s1, struct Session *s2) { if (s1 == NULL) return s2; if (s2 == NULL) return s1; if ((s1->expecting_welcome == GNUNET_NO) && (s2->expecting_welcome == GNUNET_YES)) return s1; if ((s1->expecting_welcome == GNUNET_YES) && (s2->expecting_welcome == GNUNET_NO)) return s2; if (s1->last_activity.abs_value < s2->last_activity.abs_value) return s2; if (s1->last_activity.abs_value > s2->last_activity.abs_value) return s1; if ((GNUNET_YES == s1->inbound) && (GNUNET_NO == s2->inbound)) return s1; if ((GNUNET_NO == s1->inbound) && (GNUNET_YES == s2->inbound)) return s2; return s1; } /** * 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 target who should receive this message * @param msg the message to transmit * @param msgbuf_size number of bytes in 'msg' * @param priority how important is the message (most plugins will * ignore message priority and just FIFO) * @param timeout 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 session which session must be used (or NULL for "any") * @param addr the address to use (can be NULL if the plugin * is "on its own" (i.e. re-use existing TCP connection)) * @param addrlen length of the address in bytes * @param force_address GNUNET_YES if the plugin MUST use the given address, * GNUNET_NO means the plugin may use any other address and * GNUNET_SYSERR means that only reliable existing * bi-directional connections should be used (regardless * of address) * @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 and NAT) */ static ssize_t tcp_plugin_send (void *cls, const struct GNUNET_PeerIdentity *target, const char *msg, size_t msgbuf_size, uint32_t priority, struct GNUNET_TIME_Relative timeout, struct Session *session, const void *addr, size_t addrlen, int force_address, GNUNET_TRANSPORT_TransmitContinuation cont, void *cont_cls) { struct Plugin *plugin = cls; struct Session *cand_session; struct Session *next; struct PendingMessage *pm; struct GNUNET_CONNECTION_Handle *sa; int af; const void *sb; size_t sbs; struct sockaddr_in a4; struct sockaddr_in6 a6; const struct IPv4TcpAddress *t4; const struct IPv6TcpAddress *t6; unsigned int is_natd; GNUNET_STATISTICS_update (plugin->env->stats, gettext_noop ("# bytes TCP was asked to transmit"), msgbuf_size, GNUNET_NO); /* FIXME: we could do this cheaper with a hash table * where we could restrict the iteration to entries that match * the target peer... */ is_natd = GNUNET_NO; if (session == NULL) { cand_session = NULL; next = plugin->sessions; while (NULL != (session = next)) { next = session->next; GNUNET_assert (session->client != NULL); if (0 != memcmp (target, &session->target, sizeof (struct GNUNET_PeerIdentity))) continue; if (((GNUNET_SYSERR == force_address) && (session->expecting_welcome == GNUNET_NO)) || (GNUNET_NO == force_address)) { cand_session = select_better_session (cand_session, session); continue; } if (GNUNET_SYSERR == force_address) continue; GNUNET_break (GNUNET_YES == force_address); if (addr == NULL) { GNUNET_break (0); break; } if ((addrlen != session->connect_alen) && (session->is_nat == GNUNET_NO)) continue; if ((0 != memcmp (session->connect_addr, addr, addrlen)) && (session->is_nat == GNUNET_NO)) continue; cand_session = select_better_session (cand_session, session); } session = cand_session; } if ((session == NULL) && (addr == NULL)) { #if DEBUG_TCP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "Asked to transmit to `%4s' without address and I have no existing connection (failing).\n", GNUNET_i2s (target)); #endif GNUNET_STATISTICS_update (plugin->env->stats, gettext_noop ("# bytes discarded by TCP (no address and no connection)"), msgbuf_size, GNUNET_NO); return -1; } if (session == NULL) { if (addrlen == sizeof (struct IPv6TcpAddress)) { t6 = addr; 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)) { t4 = addr; 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 { GNUNET_log_from (GNUNET_ERROR_TYPE_ERROR, "tcp", _("Address of unexpected length: %u\n"), addrlen); GNUNET_break (0); return -1; } if ((is_natd == GNUNET_YES) && (addrlen == sizeof (struct IPv6TcpAddress))) return -1; /* NAT client only works with IPv4 addresses */ if (0 == plugin->max_connections) return -1; /* saturated */ if ((is_natd == GNUNET_YES) && (NULL != plugin->nat) && (GNUNET_NO == GNUNET_CONTAINER_multihashmap_contains (plugin->nat_wait_conns, &target->hashPubKey))) { #if DEBUG_TCP_NAT GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", _("Found valid IPv4 NAT address (creating session)!\n")); #endif session = create_session (plugin, target, NULL, GNUNET_YES); GNUNET_assert (session != NULL); /* create new message entry */ pm = GNUNET_malloc (sizeof (struct PendingMessage) + msgbuf_size); /* FIXME: the memset of this malloc can be up to 2% of our total runtime */ pm->msg = (const char *) &pm[1]; memcpy (&pm[1], msg, msgbuf_size); /* FIXME: this memcpy can be up to 7% of our total run-time * (for transport service) */ pm->message_size = msgbuf_size; pm->timeout = GNUNET_TIME_relative_to_absolute (timeout); pm->transmit_cont = cont; pm->transmit_cont_cls = cont_cls; /* append pm to pending_messages list */ GNUNET_CONTAINER_DLL_insert_after (session->pending_messages_head, session->pending_messages_tail, session->pending_messages_tail, pm); GNUNET_assert (GNUNET_CONTAINER_multihashmap_put (plugin->nat_wait_conns, &target->hashPubKey, session, GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY) == GNUNET_OK); #if DEBUG_TCP_NAT GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "Created NAT WAIT connection to `%4s' at `%s'\n", GNUNET_i2s (target), GNUNET_a2s (sb, sbs)); #endif GNUNET_NAT_run_client (plugin->nat, &a4); return 0; } if ((is_natd == GNUNET_YES) && (GNUNET_YES == GNUNET_CONTAINER_multihashmap_contains (plugin->nat_wait_conns, &target->hashPubKey))) { /* Only do one NAT punch attempt per peer identity */ return -1; } sa = GNUNET_CONNECTION_create_from_sockaddr (af, sb, sbs); if (sa == NULL) { #if DEBUG_TCP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "Failed to create connection to `%4s' at `%s'\n", GNUNET_i2s (target), GNUNET_a2s (sb, sbs)); #endif GNUNET_STATISTICS_update (plugin->env->stats, gettext_noop ("# bytes discarded by TCP (failed to connect)"), msgbuf_size, GNUNET_NO); return -1; } GNUNET_assert (0 != plugin->max_connections); plugin->max_connections--; #if DEBUG_TCP_NAT GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "Asked to transmit to `%4s', creating fresh session using address `%s'.\n", GNUNET_i2s (target), GNUNET_a2s (sb, sbs)); #endif session = create_session (plugin, target, GNUNET_SERVER_connect_socket (plugin->server, sa), GNUNET_NO); session->connect_addr = GNUNET_malloc (addrlen); memcpy (session->connect_addr, addr, addrlen); session->connect_alen = addrlen; } else /* session != NULL */ { /* check if session is valid */ struct Session *ses = plugin->sessions; while ((ses != NULL) && (ses != session)) ses = ses->next; if (ses == NULL) { GNUNET_break (0); return -1; } } GNUNET_assert (session != NULL); GNUNET_assert (session->client != NULL); 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); /* create new message entry */ pm = GNUNET_malloc (sizeof (struct PendingMessage) + msgbuf_size); pm->msg = (const char *) &pm[1]; memcpy (&pm[1], msg, msgbuf_size); pm->message_size = msgbuf_size; pm->timeout = GNUNET_TIME_relative_to_absolute (timeout); pm->transmit_cont = cont; pm->transmit_cont_cls = cont_cls; /* append pm to pending_messages list */ GNUNET_CONTAINER_DLL_insert_after (session->pending_messages_head, session->pending_messages_tail, session->pending_messages_tail, pm); #if DEBUG_TCP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "Asked to transmit %u bytes to `%s', added message to list.\n", msgbuf_size, GNUNET_i2s (target)); #endif process_pending_messages (session); return msgbuf_size; } /** * 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; struct Session *session; struct Session *next; struct PendingMessage *pm; #if DEBUG_TCP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "Asked to cancel session with `%4s'\n", GNUNET_i2s (target)); #endif next = plugin->sessions; while (NULL != (session = next)) { next = session->next; if (0 != memcmp (target, &session->target, sizeof (struct GNUNET_PeerIdentity))) continue; pm = session->pending_messages_head; while (pm != NULL) { pm->transmit_cont = NULL; pm->transmit_cont_cls = NULL; pm = pm->next; } GNUNET_STATISTICS_update (session->plugin->env->stats, gettext_noop ("# transport-service disconnect requests for TCP"), 1, GNUNET_NO); disconnect_session (session); } } /** * 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; }; /** * 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; } 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 { /* 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; 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; #if DEBUG_TCP_NAT GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "received NAT probe\n"); #endif /* 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) { #if DEBUG_TCP_NAT GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "Did NOT find session for NAT probe!\n"); #endif GNUNET_SERVER_receive_done (client, GNUNET_OK); return; } #if DEBUG_TCP_NAT GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "Found session for NAT probe!\n"); #endif GNUNET_assert (GNUNET_CONTAINER_multihashmap_remove (plugin->nat_wait_conns, &tcp_nat_probe->clientIdentity.hashPubKey, session) == GNUNET_YES); if (GNUNET_OK != GNUNET_SERVER_client_get_address (client, &vaddr, &alen)) { GNUNET_break (0); GNUNET_free (session); GNUNET_SERVER_receive_done (client, GNUNET_OK); return; } GNUNET_SERVER_client_keep (client); session->client = client; session->last_activity = GNUNET_TIME_absolute_get (); session->inbound = GNUNET_NO; #if DEBUG_TCP_NAT GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "Found address `%s' for incoming connection\n", GNUNET_a2s (vaddr, alen)); #endif 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->connect_addr = t4; session->connect_alen = 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->connect_addr = t6; session->connect_alen = sizeof (struct IPv6TcpAddress); break; default: GNUNET_break_op (0); #if DEBUG_TCP_NAT GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "Bad address for incoming connection!\n"); #endif GNUNET_free (vaddr); GNUNET_SERVER_client_drop (client); GNUNET_free (session); GNUNET_SERVER_receive_done (client, GNUNET_SYSERR); return; } GNUNET_free (vaddr); session->next = plugin->sessions; plugin->sessions = session; 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; } #if DEBUG_TCP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "Received %s message from `%4s'.\n", "WELCOME", GNUNET_i2s (&wm->clientIdentity)); #endif GNUNET_STATISTICS_update (plugin->env->stats, gettext_noop ("# TCP WELCOME messages received"), 1, GNUNET_NO); session = find_session_by_client (plugin, client); if (session == NULL) { #if DEBUG_TCP_NAT GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "Received %s message from a `%4s', creating new session\n", "WELCOME", GNUNET_i2s (&wm->clientIdentity)); #endif 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 DEBUG_TCP_NAT GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "Found address `%s' for incoming connection\n", GNUNET_a2s (vaddr, alen)); #endif 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->connect_addr = t4; session->connect_alen = 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->connect_addr = t6; session->connect_alen = sizeof (struct IPv6TcpAddress); } GNUNET_free (vaddr); } else { #if DEBUG_TCP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "Did not obtain TCP socket address for incoming connection\n"); #endif } process_pending_messages (session); } else { #if DEBUG_TCP_NAT if (GNUNET_OK == GNUNET_SERVER_client_get_address (client, &vaddr, &alen)) { GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "Found address `%s' (already have session)\n", GNUNET_a2s (vaddr, alen)); GNUNET_free (vaddr); } #endif } 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; 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_TRANSPORT_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); 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 = find_session_by_client (plugin, client); if ((NULL == session) || (GNUNET_YES == session->expecting_welcome)) { GNUNET_SERVER_receive_done (client, GNUNET_SYSERR); return; } session->last_activity = GNUNET_TIME_absolute_get (); #if DEBUG_TCP > 1 GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "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)); #endif GNUNET_STATISTICS_update (plugin->env->stats, gettext_noop ("# bytes received via TCP"), ntohs (message->size), GNUNET_NO); struct GNUNET_TRANSPORT_ATS_Information distance; distance.type = htonl (GNUNET_TRANSPORT_ATS_QUALITY_NET_DISTANCE); distance.value = htonl (1); delay = plugin->env->receive (plugin->env->cls, &session->target, message, (const struct GNUNET_TRANSPORT_ATS_Information *) &distance, 1, session, (GNUNET_YES == session->inbound) ? NULL : session->connect_addr, (GNUNET_YES == session->inbound) ? 0 : session->connect_alen); if (delay.rel_value == 0) { GNUNET_SERVER_receive_done (client, GNUNET_OK); } else { #if DEBUG_TCP GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp", "Throttling receiving from `%s' for %llu ms\n", GNUNET_i2s (&session->target), (unsigned long long) delay.rel_value); #endif 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 = 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", "Destroying session of `%4s' with %s due to network-level disconnect.\n", GNUNET_i2s (&session->target), (session->connect_addr != NULL) ? tcp_address_to_string (session->plugin, session->connect_addr, session->connect_alen) : "*"); #endif 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_NO); 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); } /** * 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 (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))) { GNUNET_log_from (GNUNET_ERROR_TYPE_ERROR, "tcp", _ ("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); if (service == NULL) { GNUNET_log_from (GNUNET_ERROR_TYPE_WARNING, "tcp", _("Failed to start service.\n")); return NULL; } } else service = NULL; plugin = GNUNET_malloc (sizeof (struct Plugin)); 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->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; 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_from (GNUNET_ERROR_TYPE_ERROR, "tcp", _("Failed to find option %s in section %s!\n"), "TIMEOUT", "transport-tcp"); 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); if (bport != 0) GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "tcp", _("TCP transport listening on port %llu\n"), bport); else GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "tcp", _ ("TCP transport not listening on any port (client only)\n")); if (aport != bport) GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "tcp", _ ("TCP transport advertises itself as being on port %llu\n"), aport); 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 Session *session; struct TCPProbeContext *tcp_probe; while (NULL != (session = plugin->sessions)) disconnect_session (session); 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_NO); GNUNET_free (tcp_probe); } GNUNET_CONTAINER_multihashmap_destroy (plugin->nat_wait_conns); GNUNET_free (plugin); GNUNET_free (api); return NULL; } /* end of plugin_transport_tcp.c */