/* This file is part of GNUnet (C) 2009 Christian Grothoff (and other contributing authors) GNUnet is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. GNUnet is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with GNUnet; see the file COPYING. If not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ /** * @file transport/plugin_transport.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. * * TODO: * - consider moving DATA message (latency measurement) * to service; avoids encapsulation overheads and * would enable latency measurements for non-bidi * transports. * - * * @author Christian Grothoff */ #ifndef PLUGIN_TRANSPORT_H #define PLUGIN_TRANSPORT_H #include "gnunet_configuration_lib.h" #include "gnunet_scheduler_lib.h" #include "gnunet_transport_service.h" /** * Opaque internal context for a particular peer of the transport * service. Plugins will be given a pointer to this type and, if * cheaply possible, should pass this pointer back to the transport * service whenever additional messages from the same peer are * received. */ struct ReadyList; /** * 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 plugin_context value to pass to this plugin * to respond to the given peer (use is optional, * but may speed up processing) * @param service_context value passed to the transport-service * to identify the neighbour; will be NULL on the first * call for a given peer * @param latency estimated latency for communicating with the * given peer; should be set to GNUNET_TIME_UNIT_FOREVER_REL * until the transport has seen messages transmitted in * BOTH directions (and hence been able to do an actual * round-trip observation); a non-FOREVER latency is also used * by the transport to know that communication in both directions * using this one plugin actually works * @param peer (claimed) identity of the other peer * @param message the message, NULL if peer was disconnected * @return the new service_context that the plugin should use * for future receive calls for messages from this * particular peer */ typedef struct ReadyList * (*GNUNET_TRANSPORT_PluginReceiveCallback) (void *cls, void *plugin_context, struct ReadyList * service_context, struct GNUNET_TIME_Relative latency, const struct GNUNET_PeerIdentity * peer, const struct GNUNET_MessageHeader * message); /** * 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, size_t addrlen, struct GNUNET_TIME_Relative expires); /** * Function that will be called for each address obtained from the HELLO. * * @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 */ typedef void (*GNUNET_TRANSPORT_AddressCallback) (void *cls, const char *name, const void *addr, size_t addrlen); /** * Function that allows a transport to query the known * network addresses for a given peer. * * @param cls closure * @param timeout after how long should we time out? * @param target which peer are we looking for? * @param iter function to call for each known address * @param iter_cls closure for iter */ typedef void (*GNUNET_TRANSPORT_LookupAddress) (void *cls, struct GNUNET_TIME_Relative timeout, const struct GNUNET_PeerIdentity * target, GNUNET_TRANSPORT_AddressCallback iter, void *iter_cls); /** * 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. */ struct GNUNET_CONFIGURATION_Handle *cfg; /** * Scheduler to use. */ struct GNUNET_SCHEDULER_Handle *sched; /** * Our public key. */ struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded *my_public_key; /** * Closure for the various callbacks. */ void *cls; /** * Function that should be called by the transport plugin * whenever a message is received. */ GNUNET_TRANSPORT_PluginReceiveCallback receive; /** * Address lookup function. */ GNUNET_TRANSPORT_LookupAddress lookup; /** * 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; /** * What is the default quota (in terms of incoming bytes per * ms) for new connections? */ uint32_t default_quota_in; /** * 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 that can be used by the transport service to transmit * a message using the plugin using a fresh connection (even if * we already have a connection to this peer, this function is * required to establish a new one). * * @param cls closure * @param target who should receive this message * @param msg1 first message to transmit * @param msg2 second message to transmit (can be NULL) * @param timeout how long should we try to transmit these? * @param addrlen length of the address * @param addr the address * @return session instance if the transmission has been scheduled * NULL if the address format is invalid */ typedef void * (*GNUNET_TRANSPORT_TransmitToAddressFunction) (void *cls, const struct GNUNET_PeerIdentity * target, const struct GNUNET_MessageHeader * msg1, const struct GNUNET_MessageHeader * msg2, struct GNUNET_TIME_Relative timeout, const void *addr, size_t addrlen); /** * Function called by the GNUNET_TRANSPORT_TransmitFunction * upon "completion". * * @param cls closure * @param service_context value passed to the transport-service * to identify the neighbour * @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, struct ReadyList * service_context, 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 plugin_context value we were asked to pass to this plugin * to respond to the given peer (use is optional, * but may speed up processing), can be NULL * @param service_context value passed to the transport-service * to identify the neighbour; NULL is used to indicate * an urgent message. If the urgent message can not be * scheduled for immediate transmission, the plugin is to * call the continuation with failure immediately * @param target who should receive this message * @param msg the message to transmit * @param timeout how long to wait at most for the transmission * @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 plugin_context that should be used next time for * sending messages to the specified peer */ typedef void * (*GNUNET_TRANSPORT_TransmitFunction) (void *cls, void *plugin_context, struct ReadyList * service_context, const struct GNUNET_PeerIdentity * target, const struct GNUNET_MessageHeader * msg, struct GNUNET_TIME_Relative timeout, GNUNET_TRANSPORT_TransmitContinuation cont, void *cont_cls); /** * Function that can be called to force a disconnect from the * specified neighbour. This should also cancel all previously * scheduled transmissions. Obviously the transmission may have been * partially completed already, which is OK. The plugin is supposed * to close the connection (if applicable) and no longer call the * transmit continuation(s). * * Finally, plugin MUST NOT call the services's receive function to * notify the service that the connection to the specified target was * closed after a getting this call. * * @param cls closure * @param plugin_context value we were asked to pass to this plugin * to respond to the given peer (use is optional, * but may speed up processing), can be NULL (if * NULL was returned from the transmit function) * @param service_context must correspond to the service context * of the corresponding Transmit call; the plugin should * not cancel a send call made with a different service * context pointer! Never NULL. * @param target peer for which the last transmission is * to be cancelled */ typedef void (*GNUNET_TRANSPORT_CancelFunction) (void *cls, void *plugin_context, struct ReadyList * service_context, 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); /** * Set a quota for receiving data from the given peer; this is a * per-transport limit. The transport should limit its read/select * calls to stay below the quota (in terms of incoming data). * * @param cls closure * @param peer the peer for whom the quota is given * @param quota_in quota for receiving/sending data in bytes per ms */ typedef void (*GNUNET_TRANSPORT_SetQuota) (void *cls, const struct GNUNET_PeerIdentity * target, uint32_t quota_in); /** * Another peer has suggested an address for this * peer and transport plugin. Check that this could be a valid * address. If so, consider adding it to the list * of addresses. * * @param addr pointer to the address * @param addrlen length of addr * @return GNUNET_OK if this is a plausible address for this peer * and transport */ typedef int (*GNUNET_TRANSPORT_SuggestAddress) (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 used to send a single message to a particular * peer using the specified address. Used to validate * HELLOs. */ GNUNET_TRANSPORT_TransmitToAddressFunction send_to; /** * 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 continuationc). */ GNUNET_TRANSPORT_CancelFunction cancel; /** * 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 the transport service can use to try to enforce a * quota for the number of bytes received via this transport. * Transports that can not refuse incoming data (such as UDP) * are free to ignore these calls. */ GNUNET_TRANSPORT_SetQuota set_receive_quota; /** * Function that will be called if another peer suggested that * we should use a particular address (since he is reaching * us at that address) for this transport. */ GNUNET_TRANSPORT_SuggestAddress address_suggested; /** * Relative cost of this transport compared to others. This * is supposed to be a static cost estimate which determines * which plugins should not even be attempted if other, * cheaper transports are already working. The idea is that * the costs have roughly this relationship: * 
   * TCP < UDP < HTTP == HTTPS < SMTP
   *
*/ unsigned int cost_estimate; }; #endif