/* 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" /** * The structs defined here are used by the transport plugin to tell ATS about * the transport's properties like cost and quality and on the other side * the structs are used by highlevel components to communicate the constraints * they have for a transport to ATS * * +---+ * +-----------+ Constraints | | Plugin properties +---------+ * | Highlevel |------------> |ATS| <------------------|Transport| * | Component | ATS struct | | ATS struct | Plugin | * +-----------+ | | +---------+ * +---+ * */ #define GNUNET_TRANSPORT_ATS_ARRAY_TERMINATOR 0 /** * Enum defining all known property types for ATS * Enum values are used in the GNUNET_TRANSPORT_ATS_Information struct as (key,value)-pair * * Cost are always stored in uint32_t, so all units used to define costs * have to be normalized to fit in uint32_t [0 .. 4.294.967.295] * * To keep the elements ordered * 1..1024 : Values with a relation to cost * 1025..2048 : Values with a relation to quality * 2049..3072 : Values with a relation to availability * */ enum GNUNET_TRANSPORT_ATS_Property { /* Cost related values */ /* =================== */ /** * Volume based cost in financial units to transmit data * * Note: This value is not bound to a specific currency or unit and only * used locally. * "cent" just refers the smallest amount of money in the respective * currency. * * Unit: [cent/MB] * * Interpretation: less is better * * Examples: * LAN: 0 [cent/MB] * 2G : 10 [cent/MB] */ GNUNET_TRANSPORT_ATS_COST_FINANCIAL_PER_VOLUME = 1, /** * Time based cost in financial units to transmit data * * Note: This value is not bound to a specific currency or unit and only * used locally. * "cent" just refers the smallest amount of money in the respective * currency. * * Unit: [cent/h] * * Interpretation: less is better * * Examples: * LAN : 0 [cent/h] * Dialup: 10 [cent/h] */ GNUNET_TRANSPORT_ATS_COST_FINANCIAL_PER_TIME = 2, /** * Computational costs * * Effort of preparing data to be sent with this transport * Includes encoding, encryption and conversion of data * Partial values can be summed up: c_sum = c_enc + c_enc + c_conv * Resulting values depend on local system properties, e.g. CPU * * Unit: [ms/GB] * * Interpretation: less is better * * Examples: * * HTTPS with AES CBC-256: 7,382 * HTTPS with AES CBC-128: 5,279 * HTTPS with RC4-1024: 2,652 */ GNUNET_TRANSPORT_ATS_COST_COMPUTATIONAL = 3, /** * Energy consumption * * Energy consumption using this transport when sending with a certain * power at a certain bitrate. This is only an approximation based on: * Energy consumption E = P / D * * with: * Power P in Watt (J/s) * Datarate D in MBit/s * * Conversion between power P and dBm used by WLAN in radiotap's dBm TX power: * * Lp(dbm) = 10 log10 (P/ 1mW) * * => P = 1 mW * 10^(Lp(dbm)/10) * * Unit: [mJ/MB] * * Interpretation: less is better * * Examples: * * LAN: 0 * WLAN: 89 (600 mW @ 802.11g /w 54 MBit/s) * Bluetooth: 267 (100 mW @ BT2.0 EDR /w 3 MBit/s) */ GNUNET_TRANSPORT_ATS_COST_ENERGY_CONSUMPTION = 4, /** * Connect cost * How many bytes are transmitted to initiate a new connection using * this transport? * * Unit: [bytes] * * Interpretation: less is better * * Examples: * * UDP (No connection) : * 0 bytes * TCP (TCP 3-Way handshake): * 220 bytes Ethernet, 172 bytes TCP/IP, 122 bytes TCP * HTTP (TCP + Header) : * 477 bytes Ethernet, 429 bytes TCP/IP, 374 bytes TCP, 278 bytes HTTP * HTTPS HTTP+TLS Handshake: * 2129 bytes Ethernet, 1975 bytes TCP/IP, 1755 bytes TCP, 1403 bytes HTTPS * * */ GNUNET_TRANSPORT_ATS_COST_CONNECT = 5, /** * Bandwidth cost * * How many bandwidth is available to consume? * Used to calculate which impact sending data with this transport has * * Unit: [kB/s] * * Interpretation: more is better * * Examples: * LAN: 12,800 (100 MBit/s) * WLAN: 6,912 (54 MBit/s) * Dial-up: 8 (64 Kbit/s) * */ GNUNET_TRANSPORT_ATS_COST_BANDWITH_AVAILABLE = 6, /** * Network overhead * * How many bytes are sent over the wire when 1 kilobyte (1024 bytes) * of application data is transmitted? * A factor used with connect cost, bandwidth cost and energy cost * to describe the overhead produced by the transport protocol * * Unit: [bytes/kb] * * Interpretation: less is better * * Examples: * * TCP/IPv4 over Ethernet: 1024 + 38 + 20 + 20 = 1102 [bytes/kb] * TCP/IPv6 over Ethernet: 1024 + 38 + 20 + 40 = 1122 [bytes/kb] * UDP/IPv4 over Ethernet: 1024 + 38 + 20 + 8 = 1090 [bytes/kb] * UDP/IPv6 over Ethernet: 1024 + 38 + 40 + 8 = 1110 [bytes/kb] */ GNUNET_TRANSPORT_ATS_COST_NETWORK_OVERHEAD = 7, /* Quality related values */ /* ====================== */ /* Physical layer quality properties */ /** * Signal strength on physical layer * * Unit: [dBm] */ GNUNET_TRANSPORT_ATS_QUALITY_PHY_SIGNAL_STRENGTH = 1025, /** * Collision rate on physical layer * * Unit: [B/s] */ GNUNET_TRANSPORT_ATS_QUALITY_PHY_COLLISION_RATE = 1026, /** * Error rate on physical layer * * Unit: [B/s] */ GNUNET_TRANSPORT_ATS_QUALITY_PHY_ERROR_RATE = 1027, /* Network layer quality properties */ /** * Delay * Time between when the time packet is sent and the packet arrives * * Unit: [μs] * * Examples: * * LAN : 180 * Dialup: 4000 * WLAN : 7000 */ GNUNET_TRANSPORT_ATS_QUALITY_NET_DELAY = 1028, /** * Jitter * Time variations of the delay * 1st derivative of a delay function * * Unit: [μs] */ GNUNET_TRANSPORT_ATS_QUALITY_NET_JITTER = 1029, /** * Error rate on network layer * * Unit: [B/s] * * Examples: * * LAN : 0 * WLAN : 400 * Bluetooth : 100 * Note: This numbers are just assumptions as an example, not * measured or somehow determined */ GNUNET_TRANSPORT_ATS_QUALITY_NET_ERRORRATE = 1030, /** * Drop rate on network layer * Bytes actively dismissed by a network component during transmission * Reasons for dropped data can be full queues, congestion, quota violations... * * Unit: [B/s] * * Examples: * * LAN : 0 * WLAN : 400 * Bluetooth : 100 * Note: This numbers are just assumptions as an example, not * measured or somehow determined */ GNUNET_TRANSPORT_ATS_QUALITY_NET_DROPRATE = 1031, /** * Loss rate on network layer * Bytes lost during transmission * Reasons can be collisions, ... * * Unit: [B/s] * * Examples: * * LAN : 0 * WLAN : 40 * Bluetooth : 10 * Note: This numbers are just assumptions as an example, not measured * or somehow determined */ GNUNET_TRANSPORT_ATS_QUALITY_NET_LOSSRATE = 1032, /** * Throughput on network layer * * Unit: [kB/s] * * Examples: * * LAN : 3400 * WLAN : 1200 * Dialup: 4 * */ GNUNET_TRANSPORT_ATS_QUALITY_NET_THROUGHPUT = 1033, /* Availability related values */ /* =========================== */ /** * Is a peer reachable? */ GNUNET_TRANSPORT_ATS_AVAILABILITY_REACHABLE = 2048, /** * Is there a connection established to a peer using this transport */ GNUNET_TRANSPORT_ATS_AVAILABILITY_CONNECTED = 2049 }; /** * This structure will be used by plugins to communicate costs to ATS or by * higher level components to tell ATS their constraints. * Always a pair of (GNUNET_TRANSPORT_ATS_Property, uint32_t value). * Value is always uint32_t, so all units used to define costs have to * be normalized to fit uint32_t. */ struct GNUNET_TRANSPORT_ATS_Information { /** * ATS property type */ uint32_t type; /** * ATS property value */ uint32_t value; }; /** * 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_TRANSPORT_ATS_Cost_Information[] * This array is 0-terminated, so the last element will be a pair: * ((cost->cost_type==GNUNET_TRANSPORT_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_TRANSPORT_ATS_Cost_Information[] */ typedef void (*GNUNET_TRANSPORT_CostReport) (void *cls, const struct GNUNET_PeerIdentity *peer, const void *addr, uint16_t addrlen, struct GNUNET_TRANSPORT_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