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-rw-r--r--src/transport/plugin_transport_tcp.c2115
1 files changed, 2115 insertions, 0 deletions
diff --git a/src/transport/plugin_transport_tcp.c b/src/transport/plugin_transport_tcp.c
new file mode 100644
index 0000000..2b2d728
--- /dev/null
+++ b/src/transport/plugin_transport_tcp.c
@@ -0,0 +1,2115 @@
+/*
+ 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
+
+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
+{
+
+ /**
+ * 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).
+ *
+ * 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;
+
+ 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;
+
+};
+
+
+/**
+ * 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;
+}
+
+
+struct SessionClientCtx
+{
+ const struct GNUNET_SERVER_Client *client;
+ struct Session *ret;
+};
+
+int session_lookup_by_client_it (void *cls,
+ const 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
+ * @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);
+
+ GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp",
+ "Creating new session for peer `%4s'\n",
+ GNUNET_i2s (target));
+
+ ret = GNUNET_malloc (sizeof (struct Session));
+ ret->last_activity = GNUNET_TIME_absolute_get ();
+ ret->plugin = plugin;
+ ret->is_nat = is_nat;
+ ret->client = client;
+ ret->target = *target;
+ ret->expecting_welcome = GNUNET_YES;
+ ret->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 (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);
+ GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp",
+ "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);
+#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 PendingMessage *pm;
+ struct Plugin * plugin = session->plugin;
+
+ GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp",
+ "Disconnecting session %p for peer `%s' address `%s'\n",
+ session,
+ GNUNET_i2s (&session->target),
+ tcp_address_to_string(NULL, session->addr, session->addrlen));
+
+ GNUNET_assert (GNUNET_YES == GNUNET_CONTAINER_multihashmap_remove(plugin->sessionmap, &session->target.hashPubKey, session));
+
+ /* 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->addr);
+ GNUNET_assert (NULL == session->transmit_handle);
+ GNUNET_free (session);
+}
+
+
+/**
+ * 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 (plugin != NULL);
+ 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], 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;
+
+ /* append pm to pending_messages list */
+ GNUNET_CONTAINER_DLL_insert_tail (session->pending_messages_head,
+ session->pending_messages_tail, pm);
+
+ GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp",
+ "Asked to transmit %u bytes to `%s', added message to list.\n",
+ msgbuf_size, GNUNET_i2s (&session->target));
+
+ process_pending_messages (session);
+ return msgbuf_size;
+}
+
+struct SessionItCtx
+{
+ void * addr;
+ size_t addrlen;
+ struct Session * result;
+};
+
+int session_lookup_it (void *cls,
+ const 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));
+ GNUNET_log_from (GNUNET_ERROR_TYPE_ERROR, "tcp",
+ "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));
+ GNUNET_log_from (GNUNET_ERROR_TYPE_ERROR, "tcp",
+ "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;
+}
+
+
+/**
+ * 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 = 0;
+
+ GNUNET_assert (plugin != NULL);
+ GNUNET_assert (address != NULL);
+
+ addrlen = address->address_length;
+
+ GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp",
+ "Trying to get session for `%s' address length %i\n",
+ tcp_address_to_string(NULL, address->address, address->address_length),
+ addrlen);
+
+ /* look for existing session */
+ if (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;
+ GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "tcp",
+ "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;
+ }
+ }
+
+ 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
+ {
+ GNUNET_log_from (GNUNET_ERROR_TYPE_ERROR, "tcp",
+ _("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)))
+ {
+#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, &address->peer, NULL, GNUNET_YES);
+ session->addrlen = 0;
+ session->addr = NULL;
+ session->ats_address_network_type = ats.value;
+ GNUNET_assert (session != NULL);
+
+ GNUNET_assert (GNUNET_CONTAINER_multihashmap_put
+ (plugin->nat_wait_conns, &address->peer.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 (&session->target), GNUNET_a2s (sb, sbs));
+#endif
+ GNUNET_NAT_run_client (plugin->nat, &a4);
+ return session;
+ }
+
+ /* create new outbound session */
+ GNUNET_assert (0 != plugin->max_connections);
+ 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 (&session->target), GNUNET_a2s (sb, sbs));
+#endif
+ return NULL;
+ }
+ plugin->max_connections--;
+