moving plugin headers

1 files changed, 474 insertions, 0 deletions

diff --git a/src/include/gnunet_transport_plugin.h b/src/include/gnunet_transport_plugin.h
new file mode 100644
index 000000000..38c79f07f
--- /dev/null
+++ b/src/include/gnunet_transport_plugin.h
@@ -0,0 +1,474 @@
+/*
+     This file is part of GNUnet
+     (C) 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/gnunet_transport_plugin.h
+ * @brief API for the transport services.  This header
+ *        specifies the struct that is given to the plugin's entry
+ *        method and the other struct that must be returned.
+ *        Note that the destructors of transport plugins will
+ *        be given the value returned by the constructor
+ *        and is expected to return a NULL pointer.
+ * @author Christian Grothoff
+ */
+#ifndef PLUGIN_TRANSPORT_H
+#define PLUGIN_TRANSPORT_H
+
+#include "gnunet_configuration_lib.h"
+#include "gnunet_scheduler_lib.h"
+#include "gnunet_statistics_service.h"
+#include "gnunet_transport_service.h"
+#include "transport_selection.h"
+
+
+/**
+ * Opaque pointer that plugins can use to distinguish specific
+ * connections to a given peer.  Typically used by stateful plugins to
+ * allow the service to refer to specific streams instead of a more
+ * general notion of "some connection" to the given peer.  This is
+ * useful since sometimes (i.e. for inbound TCP connections) a
+ * connection may not have an address that can be used for meaningful
+ * distinction between sessions to the same peer.
+ */
+struct Session;
+
+/**
+ * Every 'struct Session' must begin with this header.
+ */
+struct SessionHeader
+{
+
+  /**
+   * Cached signature for PONG generation for the session.  Do not use
+   * in the plugin!
+   */
+  struct GNUNET_CRYPTO_RsaSignature pong_signature;
+
+  /**
+   * Expiration time for signature.  Do not use in the plugin!
+   */
+  struct GNUNET_TIME_Absolute pong_sig_expires;
+  
+};
+
+/**
+ * Function that will be called whenever the plugin internally
+ * cleans up a session pointer and hence the service needs to
+ * discard all of those sessions as well.  Plugins that do not
+ * use sessions can simply omit calling this function and always
+ * use NULL wherever a session pointer is needed.
+ * 
+ * @param cls closure
+ * @param peer which peer was the session for 
+ * @param session which session is being destoyed
+ */
+typedef void (*GNUNET_TRANSPORT_SessionEnd) (void *cls,
+                                             const struct GNUNET_PeerIdentity *peer,
+                                             struct Session *session);
+
+
+/**
+ * Function called by the transport for each received message.
+ * This function should also be called with "NULL" for the
+ * message to signal that the other peer disconnected.
+ *
+ * @param cls closure
+ * @param peer (claimed) identity of the other peer
+ * @param message the message, NULL if we only care about
+ *                learning about the delay until we should receive again -- FIXME!
+ * @param distance in overlay hops; use 1 unless DV (or 0 if message == NULL)
+ * @param session identifier used for this session (NULL for plugins
+ *                that do not offer bi-directional communication to the sender
+ *                using the same "connection")
+ * @param sender_address binary address of the sender (if we established the
+ *                connection or are otherwise sure of it; should be NULL
+ *                for inbound TCP/UDP connections since it it not clear
+ *                that we could establish ourselves a connection to that
+ *                IP address and get the same system)
+ * @param sender_address_len number of bytes in sender_address
+ * @return how long the plugin should wait until receiving more data
+ *         (plugins that do not support this, can ignore the return value)
+ */
+typedef struct GNUNET_TIME_Relative (*GNUNET_TRANSPORT_PluginReceiveCallback) (void *cls,
+                                                                               const struct
+                                                                               GNUNET_PeerIdentity *
+                                                                               peer,
+                                                                               const struct
+                                                                               GNUNET_MessageHeader *
+                                                                               message,
+                                                                               uint32_t distance,
+                                                                               struct Session *session,
+                                                                               const char *sender_address,
+                                                                               uint16_t sender_address_len);
+
+
+/**
+ * Function that will be called for each address the transport
+ * is aware that it might be reachable under.
+ *
+ * @param cls closure
+ * @param name name of the transport that generated the address
+ * @param addr one of the addresses of the host, NULL for the last address
+ *        the specific address format depends on the transport
+ * @param addrlen length of the address
+ * @param expires when should this address automatically expire?
+ */
+typedef void (*GNUNET_TRANSPORT_AddressNotification) (void *cls,
+                                                      const char *name,
+                                                      const void *addr,
+                                                      uint16_t addrlen,
+                                                      struct
+                                                      GNUNET_TIME_Relative
+                                                      expires);
+
+/**
+ * Function that will be called whenever the plugin receives data over
+ * the network and wants to determine how long it should wait until
+ * the next time it reads from the given peer.  Note that some plugins
+ * (such as UDP) may not be able to wait (for a particular peer), so
+ * the waiting part is optional.  Plugins that can wait should call
+ * this function, sleep the given amount of time, and call it again
+ * (with zero bytes read) UNTIL it returns zero and only then read.
+ *
+ * @param cls closure
+ * @param peer which peer did we read data from
+ * @param amount_recved number of bytes read (can be zero)
+ * @return how long to wait until reading more from this peer
+ *         (to enforce inbound quotas)
+ */
+typedef struct GNUNET_TIME_Relative (*GNUNET_TRANSPORT_TrafficReport) (void *cls,
+                                                                      const struct
+                                                                      GNUNET_PeerIdentity *peer,
+                                                                      size_t amount_recved);
+
+/**
+ * Function called whenever the plugin has to notify ATS about costs for using this transport
+ *
+ * The cost will be passed as struct GNUNET_ATS_Cost_Information[]
+ * This array is 0-terminated, so the last element will be a pair:
+ * ((cost->cost_type==GNUNET_ATS_ARRAY_TERMINATOR) && cost->cost_value==0))
+ *
+ * @param cls closure
+ * @param peer peer
+ * @param addr peer address
+ * @param addrlen address length
+ * @param cost pointer to the first element of struct GNUNET_ATS_Cost_Information[]
+ */
+typedef void (*GNUNET_TRANSPORT_CostReport) (void *cls,
+                                                                                         const struct GNUNET_PeerIdentity *peer,
+                                             const void *addr,
+                                             uint16_t addrlen,
+                                                                                         struct GNUNET_ATS_Information * cost);
+
+/**
+ * The transport service will pass a pointer to a struct
+ * of this type as the first and only argument to the
+ * entry point of each transport plugin.
+ */
+struct GNUNET_TRANSPORT_PluginEnvironment
+{
+  /**
+   * Configuration to use.
+   */
+  const struct GNUNET_CONFIGURATION_Handle *cfg;
+
+  /**
+   * Identity of this peer.
+   */
+  const struct GNUNET_PeerIdentity *my_identity;
+
+  /**
+   * Pointer (!) to our HELLO message.  Note that the address
+   * referred to "*our_hello" might change over time.
+   */
+  struct GNUNET_HELLO_Message *const*our_hello;
+
+  /**
+   * Closure for the various callbacks.
+   */
+  void *cls;
+
+  /**
+   * Handle for reporting statistics.
+   */
+  struct GNUNET_STATISTICS_Handle *stats;
+
+  /**
+   * Function that should be called by the transport plugin
+   * whenever a message is received.
+   */
+  GNUNET_TRANSPORT_PluginReceiveCallback receive;
+
+  /**
+   * Function that must be called by each plugin to notify the
+   * transport service about the addresses under which the transport
+   * provided by the plugin can be reached.
+   */
+  GNUNET_TRANSPORT_AddressNotification notify_address;
+
+  /**
+   * Inform service about traffic received, get information
+   * about when we might be willing to receive more.
+   */
+  GNUNET_TRANSPORT_TrafficReport traffic_report;
+
+  /**
+   * Function that must be called by the plugin when a non-NULL
+   * session handle stops being valid (is destroyed).
+   */
+  GNUNET_TRANSPORT_SessionEnd session_end;
+
+  /**
+   * Inform service about costs for using this transport plugin
+   */
+  GNUNET_TRANSPORT_CostReport cost_report;
+
+  /**
+   * What is the maximum number of connections that this transport
+   * should allow?  Transports that do not have sessions (such as
+   * UDP) can ignore this value.
+   */
+  uint32_t max_connections;
+
+};
+
+
+/**
+ * Function called by the GNUNET_TRANSPORT_TransmitFunction
+ * upon "completion".
+ *
+ * @param cls closure
+ * @param target who was the recipient of the message?
+ * @param result GNUNET_OK on success
+ *               GNUNET_SYSERR if the target disconnected;
+ *               disconnect will ALSO be signalled using
+ *               the ReceiveCallback.
+ */
+typedef void
+  (*GNUNET_TRANSPORT_TransmitContinuation) (void *cls,
+                                            const struct GNUNET_PeerIdentity *
+                                            target, int result);
+
+
+/**
+ * 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 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 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)
+ */
+typedef ssize_t
+  (*GNUNET_TRANSPORT_TransmitFunction) (void *cls,
+                                        const struct GNUNET_PeerIdentity *
+                                        target,
+                                        const char *msgbuf,
+                                        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);
+
+
+/**
+ * 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
+ */
+typedef void
+  (*GNUNET_TRANSPORT_DisconnectFunction) (void *cls,
+                                          const struct GNUNET_PeerIdentity *
+                                          target);
+
+
+/**
+ * Function called by the pretty printer for the resolved address for
+ * each human-readable address obtained.
+ *
+ * @param cls closure
+ * @param hostname one of the names for the host, NULL
+ *        on the last call to the callback
+ */
+typedef void (*GNUNET_TRANSPORT_AddressStringCallback) (void *cls,
+                                                        const char *address);
+
+
+/**
+ * Convert the transports address to a nice, human-readable
+ * format.
+ *
+ * @param cls closure
+ * @param name name of the transport that generated the address
+ * @param addr one of the addresses of the host, NULL for the last address
+ *        the specific address format depends on the transport
+ * @param addrlen length of the address
+ * @param numeric should (IP) addresses be displayed in numeric form?
+ * @param timeout after how long should we give up?
+ * @param asc function to call on each string
+ * @param asc_cls closure for asc
+ */
+typedef void
+  (*GNUNET_TRANSPORT_AddressPrettyPrinter) (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);
+
+
+/**
+ * Another peer has suggested an address for this peer and transport
+ * plugin.  Check that this could be a valid address.  This function
+ * is not expected to 'validate' the address in the sense of trying to
+ * connect to it but simply to see if the binary format is technically
+ * legal for establishing a connection to this peer (and make sure that
+ * the address really corresponds to our network connection/settings
+ * and not some potential man-in-the-middle).
+ *
+ * @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
+ */
+typedef int
+(*GNUNET_TRANSPORT_CheckAddress) (void *cls,
+                                  const void *addr, size_t addrlen);
+
+
+/**
+ * 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
+ * @param addr binary address
+ * @param addr_len length of the address
+ * @return string representing the same address 
+ */
+typedef const char* (*GNUNET_TRANSPORT_AddressToString) (void *cls,
+                                                         const void *addr,
+                                                         size_t addrlen);
+
+
+/**
+ * Each plugin is required to return a pointer to a struct of this
+ * type as the return value from its entry point.
+ */
+struct GNUNET_TRANSPORT_PluginFunctions
+{
+
+  /**
+   * Closure for all of the callbacks.
+   */
+  void *cls;
+
+  /**
+   * Function that the transport service will use to transmit data to
+   * another peer.  May be NULL for plugins that only support
+   * receiving data.  After this call, the plugin call the specified
+   * continuation with success or error before notifying us about the
+   * target having disconnected.
+   */
+  GNUNET_TRANSPORT_TransmitFunction send;
+
+  /**
+   * Function that can be used to force the plugin to disconnect from
+   * the given peer and cancel all previous transmissions (and their
+   * continuations).  Note that if the transport does not have
+   * sessions / persistent connections (for example, UDP), this
+   * function may very well do nothing.
+   */
+  GNUNET_TRANSPORT_DisconnectFunction disconnect;
+
+  /**
+   * Function to pretty-print addresses.  NOTE: this function is not
+   * yet used by transport-service, but will be used in the future
+   * once the transport-API has been completed.
+   */
+  GNUNET_TRANSPORT_AddressPrettyPrinter address_pretty_printer;
+
+  /**
+   * 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.
+   */
+  GNUNET_TRANSPORT_CheckAddress check_address;
+
+  /**
+   * Function that will be called to convert a binary address
+   * to a string (numeric conversion only).
+   */
+  GNUNET_TRANSPORT_AddressToString address_to_string;
+
+};
+
+
+#endif