gnunet_transport_communication_service.h (12951B)
1 /* 2 This file is part of GNUnet. 3 Copyright (C) 2009-2019 GNUnet e.V. 4 5 GNUnet is free software: you can redistribute it and/or modify it 6 under the terms of the GNU Affero General Public License as published 7 by the Free Software Foundation, either version 3 of the License, 8 or (at your option) any later version. 9 10 GNUnet is distributed in the hope that it will be useful, but 11 WITHOUT ANY WARRANTY; without even the implied warranty of 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 13 Affero General Public License for more details. 14 15 You should have received a copy of the GNU Affero General Public License 16 along with this program. If not, see <http://www.gnu.org/licenses/>. 17 18 SPDX-License-Identifier: AGPL3.0-or-later 19 */ 20 21 /** 22 * @addtogroup Backbone 23 * @{ 24 * 25 * @author Christian Grothoff 26 * 27 * @file 28 * API of the transport service towards the communicator processes. 29 * 30 * @defgroup TNG Transport Next Generation service 31 * Low-level communication with other peers 32 * 33 * @see [Documentation](https://gnunet.org/transport-service) 34 * 35 * @{ 36 */ 37 38 #ifndef GNUNET_TRANSPORT_COMMUNICATION_SERVICE_H 39 #define GNUNET_TRANSPORT_COMMUNICATION_SERVICE_H 40 41 #ifdef __cplusplus 42 extern "C" { 43 #if 0 /* keep Emacsens' auto-indent happy */ 44 } 45 #endif 46 #endif 47 48 49 #include "gnunet_util_lib.h" 50 51 /** 52 * Version number of the transport communication API. 53 */ 54 #define GNUNET_TRANSPORT_COMMUNICATION_VERSION 0x00000000 55 56 /** 57 * Queue length 58 */ 59 #define GNUNET_TRANSPORT_QUEUE_LENGTH_UNLIMITED UINT64_MAX 60 61 /** 62 * Function called by the transport service to initialize a 63 * message queue given address information about another peer. 64 * If and when the communication channel is established, the 65 * communicator must call #GNUNET_TRANSPORT_communicator_mq_add() 66 * to notify the service that the channel is now up. It is 67 * the responsibility of the communicator to manage sane 68 * retries and timeouts for any @a peer/@a address combination 69 * provided by the transport service. Timeouts and retries 70 * do not need to be signalled to the transport service. 71 * 72 * @param cls closure 73 * @param peer identity of the other peer 74 * @param address where to send the message, human-readable 75 * communicator-specific format, 0-terminated, UTF-8 76 * @return #GNUNET_OK on success, #GNUNET_SYSERR if the provided address is 77 * invalid, #GNUNET_NO if this address is already (being) connected to. 78 */ 79 typedef int (*GNUNET_TRANSPORT_CommunicatorMqInit) ( 80 void *cls, 81 const struct GNUNET_PeerIdentity *peer, 82 const char *address); 83 84 85 /** 86 * Opaque handle to the transport service for communicators. 87 */ 88 struct GNUNET_TRANSPORT_CommunicatorHandle; 89 90 91 /** 92 * What characteristics does this communicator have? 93 * 94 * FIXME: may want to distinguish bi-directional as well, 95 * should we define a bit for that? Needed in DV logic (handle_dv_learn)! 96 */ 97 enum GNUNET_TRANSPORT_CommunicatorCharacteristics 98 { 99 /** 100 * Characteristics are unknown (e.g. DV). 101 */ 102 GNUNET_TRANSPORT_CC_UNKNOWN = 0, 103 104 /** 105 * Transmission is reliabile (with ACKs), e.g. TCP/HTTP/HTTPS. 106 */ 107 GNUNET_TRANSPORT_CC_RELIABLE = 1, 108 109 /** 110 * Transmission is unreliable (e.g. UDP) 111 */ 112 GNUNET_TRANSPORT_CC_UNRELIABLE = 2 113 }; 114 115 116 /** 117 * Function called when the transport service has received a 118 * backchannel message for this communicator (!) via a different 119 * return path. 120 * 121 * Typically used to receive messages of type 122 * #GNUNET_MESSAGE_TYPE_TRANSPORT_COMMUNICATOR_FC_LIMITS or 123 * #GNUNET_MESSAGE_TYPE_TRANSPORT_COMMUNICATOR_KX_CONFIRMATION 124 * as well as communicator-specific messages to assist with 125 * NAT traversal. 126 * 127 * @param cls closure 128 * @param sender which peer sent the notification 129 * @param msg payload 130 */ 131 typedef void (*GNUNET_TRANSPORT_CommunicatorNotify) ( 132 void *cls, 133 const struct GNUNET_PeerIdentity *sender, 134 const struct GNUNET_MessageHeader *msg); 135 136 137 /** 138 * Function to start burst, if request by transport service. 139 * 140 * @param address The address to start the burst against. 141 */ 142 typedef void (*GNUNET_TRANSPORT_StartBurstNotify) (const char *address, 143 struct GNUNET_TIME_Relative rtt, 144 struct GNUNET_PeerIdentity *peer); 145 146 /** 147 * Connect to the transport service. 148 * 149 * @param cfg configuration to use 150 * @param config_section_name section of the configuration to use for 151 * options 152 * @param addr_prefix address prefix for addresses supported by this 153 * communicator, could be NULL for incoming-only communicators 154 * @param cc what characteristics does the communicator have? 155 * @param mq_init function to call to initialize a message queue given 156 * the address of another peer, can be NULL if the 157 * communicator only supports receiving messages 158 * @param mq_init_cls closure for @a mq_init 159 * @param notify_cb function to pass backchannel messages to communicator 160 * @param notify_cb_cls closure for @a notify_cb 161 * @param sb Function to start burst, if request by transport service. 162 * @return NULL on error 163 */ 164 struct GNUNET_TRANSPORT_CommunicatorHandle * 165 GNUNET_TRANSPORT_communicator_connect ( 166 const struct GNUNET_CONFIGURATION_Handle *cfg, 167 const char *config_section_name, 168 const char *addr_prefix, 169 enum GNUNET_TRANSPORT_CommunicatorCharacteristics cc, 170 GNUNET_TRANSPORT_CommunicatorMqInit mq_init, 171 void *mq_init_cls, 172 GNUNET_TRANSPORT_CommunicatorNotify notify_cb, 173 void *notify_cb_cls, 174 GNUNET_TRANSPORT_StartBurstNotify sb); 175 176 177 /** 178 * Disconnect from the transport service. 179 * 180 * @param ch handle returned from connect 181 */ 182 void 183 GNUNET_TRANSPORT_communicator_disconnect ( 184 struct GNUNET_TRANSPORT_CommunicatorHandle *ch); 185 186 187 /* ************************* Receiving *************************** */ 188 189 /** 190 * Function called to notify communicator that we have received 191 * and processed the message. Used for flow control (if supported 192 * by the communicator). 193 * 194 * @param cls closure 195 * @param success #GNUNET_SYSERR on failure (try to disconnect/reset connection) 196 * #GNUNET_OK on success 197 */ 198 typedef void 199 (*GNUNET_TRANSPORT_MessageCompletedCallback) (void *cls, 200 int success); 201 202 203 /** 204 * Notify transport service that the communicator has received 205 * a message. 206 * 207 * @param handle connection to transport service 208 * @param sender presumed sender of the message (details to be checked 209 * by higher layers) 210 * @param msg the message 211 * @param expected_addr_validity how long does the communicator believe it 212 * will continue to be able to receive messages from the same address 213 * on which it received this message? 214 * @param cb function to call once handling the message is done, NULL if 215 * flow control is not supported by this communicator 216 * @param cb_cls closure for @a cb 217 * @return #GNUNET_OK if all is well, #GNUNET_NO if the message was 218 * immediately dropped due to memory limitations (communicator 219 * should try to apply back pressure), 220 * #GNUNET_SYSERR if the message could not be delivered because 221 * the transport service is not yet up 222 */ 223 int 224 GNUNET_TRANSPORT_communicator_receive ( 225 struct GNUNET_TRANSPORT_CommunicatorHandle *handle, 226 const struct GNUNET_PeerIdentity *sender, 227 const struct GNUNET_MessageHeader *msg, 228 struct GNUNET_TIME_Relative expected_addr_validity, 229 GNUNET_TRANSPORT_MessageCompletedCallback cb, 230 void *cb_cls); 231 232 233 /** 234 * The communicator tells the transport service that it finished the burst.* 235 * @param handle connection to transport service. 236 */ 237 void 238 GNUNET_TRANSPORT_communicator_burst_finished (struct GNUNET_TRANSPORT_CommunicatorHandle *ch); 239 240 /* ************************* Discovery *************************** */ 241 242 /** 243 * Handle returned to identify the internal data structure the transport 244 * API has created to manage a message queue to a particular peer. 245 */ 246 struct GNUNET_TRANSPORT_QueueHandle; 247 248 249 /** 250 * Possible states of a connection. 251 */ 252 enum GNUNET_TRANSPORT_ConnectionStatus 253 { 254 /** 255 * Connection is down. 256 */ 257 GNUNET_TRANSPORT_CS_DOWN = -1, 258 259 /** 260 * this is an outbound connection (transport initiated) 261 */ 262 GNUNET_TRANSPORT_CS_OUTBOUND = 0, 263 264 /** 265 * this is an inbound connection (communicator initiated) 266 */ 267 GNUNET_TRANSPORT_CS_INBOUND = 1 268 }; 269 270 271 /** 272 * Notify transport service that a MQ became available due to an 273 * "inbound" connection or because the communicator discovered the 274 * presence of another peer. 275 * 276 * @param ch connection to transport service 277 * @param peer peer with which we can now communicate 278 * @param address address in human-readable format, 0-terminated, UTF-8 279 * @param mtu maximum message size supported by queue, 0 if 280 * sending is not supported, SIZE_MAX for no MTU 281 * @param q_len number of messages that can be send through this queue 282 * @param priority queue priority. Queues with highest priority should be 283 * used 284 * @param nt which network type does the @a address belong to? 285 * @param cs what is the connection status of the queue? 286 * @param mq message queue of the @a peer 287 * @return API handle identifying the new MQ 288 */ 289 struct GNUNET_TRANSPORT_QueueHandle * 290 GNUNET_TRANSPORT_communicator_mq_add ( 291 struct GNUNET_TRANSPORT_CommunicatorHandle *ch, 292 const struct GNUNET_PeerIdentity *peer, 293 const char *address, 294 uint32_t mtu, 295 uint64_t q_len, 296 uint32_t priority, 297 enum GNUNET_NetworkType nt, 298 enum GNUNET_TRANSPORT_ConnectionStatus cs, 299 struct GNUNET_MQ_Handle *mq); 300 301 /** 302 * Notify transport service that an MQ was updated 303 * 304 * @param ch connection to transport service 305 * @param u_qh the queue to update 306 * @param q_len number of messages that can be send through this queue 307 * @param priority queue priority. Queues with highest priority should be 308 * used 309 */ 310 void 311 GNUNET_TRANSPORT_communicator_mq_update ( 312 struct GNUNET_TRANSPORT_CommunicatorHandle *ch, 313 const struct GNUNET_TRANSPORT_QueueHandle *u_qh, 314 uint64_t q_len, 315 uint32_t priority); 316 317 /** 318 * Notify transport service that an MQ became unavailable due to a 319 * disconnect or timeout. 320 * 321 * @param qh handle for the queue that must be invalidated 322 */ 323 void 324 GNUNET_TRANSPORT_communicator_mq_del (struct GNUNET_TRANSPORT_QueueHandle *qh); 325 326 327 /** 328 * Internal representation of an address a communicator is 329 * currently providing for the transport service. 330 */ 331 struct GNUNET_TRANSPORT_AddressIdentifier; 332 333 334 /** 335 * Notify transport service about an address that this communicator 336 * provides for this peer. 337 * 338 * @param ch connection to transport service 339 * @param address our address in human-readable format, 0-terminated, UTF-8 340 * @param nt which network type does the address belong to? 341 * @param expiration when does the communicator foresee this address expiring? 342 */ 343 struct GNUNET_TRANSPORT_AddressIdentifier * 344 GNUNET_TRANSPORT_communicator_address_add ( 345 struct GNUNET_TRANSPORT_CommunicatorHandle *ch, 346 const char *address, 347 enum GNUNET_NetworkType nt, 348 struct GNUNET_TIME_Relative expiration); 349 350 351 /** 352 * Notify transport service about an address that this communicator 353 * no longer provides for this peer. 354 * 355 * @param ai address that is no longer provided 356 */ 357 void 358 GNUNET_TRANSPORT_communicator_address_remove ( 359 struct GNUNET_TRANSPORT_AddressIdentifier *ai); 360 361 /** 362 * Notify transport service that this communicator no longer provides all its addresses for this peer. 363 * 364 * @param ch The communicator handle. 365 */ 366 void 367 GNUNET_TRANSPORT_communicator_address_remove_all ( 368 struct GNUNET_TRANSPORT_CommunicatorHandle *ch); 369 370 /** 371 * The communicator asks the transport service to route a message via 372 * a different path to another communicator service at another peer. 373 * This must only be done for special control traffic (as there is no 374 * flow control for this API), such as acknowledgements, and generally 375 * only be done if the communicator is uni-directional (i.e. cannot 376 * send the message back itself). 377 * 378 * While backchannel messages are signed and encrypted, communicators 379 * must protect against replay attacks when using this backchannel 380 * communication! 381 * 382 * @param ch handle of this communicator 383 * @param pid peer to send the message to 384 * @param comm name of the communicator to send the message to 385 * @param header header of the message to transmit and pass via the 386 * notify-API to @a pid's communicator @a comm 387 */ 388 void 389 GNUNET_TRANSPORT_communicator_notify ( 390 struct GNUNET_TRANSPORT_CommunicatorHandle *ch, 391 const struct GNUNET_PeerIdentity *pid, 392 const char *comm, 393 const struct GNUNET_MessageHeader *header); 394 395 396 #if 0 /* keep Emacsens' auto-indent happy */ 397 { 398 #endif 399 #ifdef __cplusplus 400 } 401 #endif 402 403 /* ifndef GNUNET_TRANSPORT_COMMUNICATOR_SERVICE_H */ 404 #endif 405 406 /** @} */ /* end of group */ 407 408 /** @} */ /* end of group addition */ 409 410 /* end of gnunet_transport_communicator_service.h */