/* silcpacket.h Author: Pekka Riikonen Copyright (C) 1997 - 2005 Pekka Riikonen This program 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; version 2 of the License. This program 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. */ /****h* silccore/Packet Protocol Interface * * DESCRIPTION * * Implementation of the packet routines for sending and receiving * SILC Packets. These includes the data sending routines and data * reading routines, encrypting and decrypting routines, packet assembling * and packet parsing routines. * ***/ #ifndef SILCPACKET_H #define SILCPACKET_H /* XXX many of these could go to silcpacket_i.h */ /* Maximum packet length */ #define SILC_PACKET_MAX_LEN 0xffff /* Maximum length of ID */ #define SILC_PACKET_MAX_ID_LEN 28 /****d* silccore/SilcPacketAPI/SilcPacketType * * NAME * * typedef SilcUInt8 SilcPacketType; * * DESCRIPTION * * SILC packet type definition and all the packet types. * * SOURCE */ typedef SilcUInt8 SilcPacketType; /* SILC Packet types. */ #define SILC_PACKET_NONE 0 /* NULL, never sent */ #define SILC_PACKET_DISCONNECT 1 /* Disconnection */ #define SILC_PACKET_SUCCESS 2 /* Success */ #define SILC_PACKET_FAILURE 3 /* Failure */ #define SILC_PACKET_REJECT 4 /* Rejected */ #define SILC_PACKET_NOTIFY 5 /* Notify message */ #define SILC_PACKET_ERROR 6 /* Error message */ #define SILC_PACKET_CHANNEL_MESSAGE 7 /* Message for channel */ #define SILC_PACKET_CHANNEL_KEY 8 /* Key of the channel */ #define SILC_PACKET_PRIVATE_MESSAGE 9 /* Private message */ #define SILC_PACKET_PRIVATE_MESSAGE_KEY 10 /* Private message key*/ #define SILC_PACKET_COMMAND 11 /* Command */ #define SILC_PACKET_COMMAND_REPLY 12 /* Reply to a command */ #define SILC_PACKET_KEY_EXCHANGE 13 /* Start of KE */ #define SILC_PACKET_KEY_EXCHANGE_1 14 /* KE1 */ #define SILC_PACKET_KEY_EXCHANGE_2 15 /* KE2 */ #define SILC_PACKET_CONNECTION_AUTH_REQUEST 16 /* Request of auth meth */ #define SILC_PACKET_CONNECTION_AUTH 17 /* Connectinon auth */ #define SILC_PACKET_NEW_ID 18 /* Sending new ID */ #define SILC_PACKET_NEW_CLIENT 19 /* Client registering */ #define SILC_PACKET_NEW_SERVER 20 /* Server registering */ #define SILC_PACKET_NEW_CHANNEL 21 /* Channel registering */ #define SILC_PACKET_REKEY 22 /* Re-key start */ #define SILC_PACKET_REKEY_DONE 23 /* Re-key done */ #define SILC_PACKET_HEARTBEAT 24 /* Heartbeat */ #define SILC_PACKET_KEY_AGREEMENT 25 /* Key Agreement request */ #define SILC_PACKET_RESUME_ROUTER 26 /* Backup router resume */ #define SILC_PACKET_FTP 27 /* File Transfer */ #define SILC_PACKET_RESUME_CLIENT 28 /* Client resume */ #define SILC_PACKET_PRIVATE 200 /* Private range start */ #define SILC_PACKET_MAX 255 /* RESERVED */ /***/ /****d* silccore/SilcPacketAPI/SilcPacketFlags * * NAME * * typedef SilcUInt8 SilcPacketFlags; * * DESCRIPTION * * SILC packet flags type definition and all the packet flags. * * SOURCE */ typedef SilcUInt8 SilcPacketFlags; /* All defined packet flags */ #define SILC_PACKET_FLAG_NONE 0x00 /* No flags */ #define SILC_PACKET_FLAG_PRIVMSG_KEY 0x01 /* Private message key */ #define SILC_PACKET_FLAG_LIST 0x02 /* Packet is a list */ #define SILC_PACKET_FLAG_BROADCAST 0x04 /* Packet is a broadcast */ #define SILC_PACKET_FLAG_COMPRESSED 0x08 /* Payload is compressed */ /* Impelemntation specific flags */ #define SILC_PACKET_FLAG_LONG_PAD 0x10 /* Use maximum padding */ /***/ /****s* silccore/SilcPacketAPI/SilcPacketEngine * * NAME * * typedef struct SilcPacketEngineStruct *SilcPacketEngine; * * DESCRIPTION * * The packet engine context, allocated by silc_packet_engine_start. * The engine is destroyed with silc_packet_engine_stop. * ***/ typedef struct SilcPacketEngineStruct *SilcPacketEngine; /****s* silccore/SilcPacketAPI/SilcPacketStream * * NAME * * typedef struct SilcPacketStreamStruct *SilcPacketStream; * * DESCRIPTION * * The packet stream context, allocated by silc_packet_stream_create. * The stream is destroyed with silc_packet_stream_destroy. * ***/ typedef struct SilcPacketStreamStruct *SilcPacketStream; /****s* silccore/SilcPacketAPI/SilcPacket * * NAME * * typedef struct SilcPacketStruct *SilcPacket; * * DESCRIPTION * * The SilcPacket is returned by the packet engine in the SilcPacketReceive * callback. The application can parse the data payload from the * SilcPacket. Also packet type, flags, and sender and destination * IDs are available. The application must free the packet with the * silc_packet_free function. * * SOURCE */ typedef struct SilcPacketStruct { struct SilcPacketStruct *next; SilcBufferStruct buffer; /* Packet data payload */ unsigned char *src_id; /* Source ID */ unsigned char *dst_id; /* Destination ID */ unsigned int src_id_len : 6; /* Source ID length */ unsigned int src_id_type : 2; /* Source ID type */ unsigned int dst_id_len : 6; /* Destination ID length */ unsigned int dst_id_type : 2; /* Destination ID type */ SilcPacketType type; /* Packet type */ SilcPacketFlags flags; /* Packet flags */ } *SilcPacket; /***/ /****d* silcutil/SilcPacketAPI/SilcPacketError * * NAME * * typedef enum { ... } SilcPacketError * * DESCRIPTION * * Packet errors. This is returned in the error callback. If application * needs the actual lower level stream error, it needs to retrieve it * from the actual stream. * * SOURCE */ typedef enum { SILC_PACKET_ERR_READ, /* Error while reading */ SILC_PACKET_ERR_WRITE, /* Error while writing */ SILC_PACKET_ERR_MAC_FAILED, /* Packet MAC check failed */ SILC_PACKET_ERR_DECRYPTION_FAILED, /* Packet decryption failed */ SILC_PACKET_ERR_MALFORMED, /* Packet is malformed */ SILC_PACKET_ERR_NO_MEMORY, /* System out of memory */ } SilcPacketError; /***/ /****f* silccore/SilcPacketAPI/SilcPacketReceiveCb * * SYNOPSIS * * typedef void (*SilcPacketReceiveCb)(SilcPacketEngine engine, * SilcPacketStream stream, * SilcPacket packet, * void *callback_context, * void *app_context); * * DESCRIPTION * * The packet receive callback is called by the packet engine when a new * SILC Packet has arrived. The application must free the returned * SilcPacket with silc_packet_free. This callback is set in the * SilcPacketCallbacks structure. * ***/ typedef void (*SilcPacketReceiveCb)(SilcPacketEngine engine, SilcPacketStream stream, SilcPacket packet, void *callback_context, void *app_context); /****f* silccore/SilcPacketAPI/SilcPacketEosCb * * SYNOPSIS * * typedef void (*SilcPacketEosCb)(SilcPacketEngine engine, * SilcPacketStream stream, * void *callback_context, * void *app_context); * * DESCRIPTION * * The End Of Stream (EOS) callback, that is called by the packet engine * when the underlaying stream has ended. No more data can be sent to * the stream or read from it. The `stream' must be destroyed by * calling the silc_packet_stream_destroy. This callback is set in the * SilcPacketCallbacks structure. * ***/ typedef void (*SilcPacketEosCb)(SilcPacketEngine engine, SilcPacketStream stream, void *callback_context, void *app_context); /****f* silccore/SilcPacketAPI/SilcPacketErrorCb * * SYNOPSIS * * typedef void (*SilcPacketErrorCb)(SilcPacketEngine engine, * SilcPacketStream stream, * SilcPacketError error, * void *callback_context, * void *app_context); * * DESCRIPTION * * The error callback that is called by the packet engine if an error * occurs. The `error' will indicate the error. This callback is set * in the SilcPacketCallbacks structure. * ***/ typedef void (*SilcPacketErrorCb)(SilcPacketEngine engine, SilcPacketStream stream, SilcPacketError error, void *callback_context, void *app_context); /****s* silccore/SilcPacketAPI/SilcPacketStream * * NAME * * typedef struct SilcPacketStreamStruct *SilcPacketStream; * * DESCRIPTION * * This structure is sent as argument to the silc_packet_engine_start * function to set the callback functions for the packet engine. The * packet engine will call the callbacks when necessary. Application * must always be provided for the packet engine. * * SOURCE */ typedef struct { SilcPacketReceiveCb packet_receive; /* Called when packet is received */ SilcPacketEosCb eos; /* Called on end of stream */ SilcPacketErrorCb error; /* Called on an error */ } SilcPacketCallbacks; /***/ /* Prototypes */ /****f* silccore/SilcPacketAPI/silc_packet_engine_start * * SYNOPSIS * * SilcPacketEngine * silc_packet_engine_start(SilcSchedule schedule, SilcRng rng, bool router, * SilcPacketCallbacks *callbacks, * void *callback_context); * * DESCRIPTION * * Create new packet engine for processing incoming and outgoing packets. * If `rng' is non-NULL that RNG will be used to create necessary random * numbers during packet processing. If NULL, Global RNG will be used. * If `router' is TRUE then the application is considered to be router * server, and certain packets are handled differently. Client and normal * server must set it to FALSE. The `callbacks' is a SilcPacketCallbacks * structure provided by the caller which includes the callbacks that is * called when for example packet is received, or end of stream is called * * NOTES * * The packet engine is thread safe. Also the `schedule' and `rng' are * thread safe. You can use one packet engine in multi threaded * application. * ***/ SilcPacketEngine silc_packet_engine_start(SilcSchedule schedule, SilcRng rng, bool router, SilcPacketCallbacks *callbacks, void *callback_context); /****f* silccore/SilcPacketAPI/silc_packet_engine_stop * * SYNOPSIS * * void silc_packet_engine_stop(SilcPacketEngine engine); * * DESCRIPTION * * Stop the packet engine. No new packets can be sent or received after * calling this, and the `engine' will become invalid. * ***/ void silc_packet_engine_stop(SilcPacketEngine engine); /****f* silccore/SilcPacketAPI/silc_packet_stream_create * * SYNOPSIS * * SilcPacketStream silc_packet_stream_create(SilcPacketEngine engine, * SilcStream stream); * * DESCRIPTION * * Create new packet stream and use the `stream' as underlaying stream. * Usually the `stream' would be a socket stream, but it can be any * stream. After this function returns, packets can immediately be * sent to or received from the stream. * * NOTES * * SilcPacketStream cannot be used with silc_stream_* routines (such as * silc_stream_read and silc_stream_write) because of its special nature. * Use the silc_packet_send and the silc_packet_send_ext to send packets. * To read packets you will receive the packet receive callback from * packet engine. Destroy the stream with silc_packet_stream_destroy. * * If you need to send only one type of SILC packets, then it is possible * to create SILC Packet Streamer with silc_packet_streamer_create, which * can be used with silc_stream_read and silc_stream_write. * * The SilcPacketStream is not thread safe. If you share same stream * with multiple threads concurrency control need to be employed. It * is recommended to create new SilcPacketStream for every thread. * ***/ SilcPacketStream silc_packet_stream_create(SilcPacketEngine engine, SilcStream stream); /****f* silccore/SilcPacketAPI/silc_packet_stream_destroy * * SYNOPSIS * * void silc_packet_stream_destroy(SilcPacketStream stream); * * DESCRIPTION * * Destroy packet stream and the underlaying stream. This will also * send end of stream to the underlaying stream. * ***/ void silc_packet_stream_destroy(SilcPacketStream stream); /****f* silccore/SilcPacketAPI/silc_packet_streamer_create * * SYNOPSIS * * SilcStream silc_packet_streamer_create(SilcPacketStream stream, * SilcPacketType packet_type, * SilcPacketFlags packet_flags); * * DESCRIPTION * * This function can be used to create a SILC Packet Streamer that will * stream only one type of packet indicated by `packet_type' with packet * flags `packet_flags'. This is special purpose function as usually * multiple different types of packets need to be sent in application. * There are cases however when creating streamer is simpler and more * efficient. Cases such as file transfer stream or other data streams * that only send and receive one type of packet. While it would be * possible to use silc_packet_send function to send packets it is * more efficient to create the SILC Packet Streamer and use the * silc_stream_read and silc_stream_write functions. * * The encryption and decryption keys, and other information will be * retrieved from the packet stream indicated by `stream', which must be * created before creating the streamer. * * NOTES * * The packet type that is assocated with the packet stream `stream' will * only be available through the returned SilcStream. That packet type * will not be delivered to the packet callbacks. To return to the * normal operation destroy the streamer silc_packet_streamer_destroy. * ***/ SilcStream silc_packet_streamer_create(SilcPacketStream stream, SilcPacketType packet_type, SilcPacketFlags packet_flags); /****f* silccore/SilcPacketAPI/silc_packet_streamer_destroy * * SYNOPSIS * * void silc_packet_streamer_destroy(SilcStream stream); * * DESCRIPTION * * Destroys the created packet streamer. Use this function only for * stream created with silc_packet_streamer_create. The packet type * that was associated with the streamer can be received in the packet * callbacks after the streamer is destroyed. * ***/ void silc_packet_streamer_destroy(SilcStream stream); /****f* silccore/SilcPacketAPI/silc_packet_stream_get_stream * * SYNOPSIS * * SilcStream silc_packet_stream_get_stream(SilcPacketStream stream); * * DESCRIPTION * * Returns the actual stream that is associated with the packet stream * `stream'. The caller must not free the returned stream. The returned * stream is the same pointer that was set for silc_packet_stream_create. * This function couled be used for example when an error callback is * called by the packet engine to retrieve the actual lower level error * from the stream. * ***/ SilcStream silc_packet_stream_get_stream(SilcPacketStream stream); /****f* silccore/SilcPacketAPI/silc_packet_stream_callbacks * * SYNOPSIS * * void silc_packet_stream_callbacks(SilcPacketStream stream, * SilcPacketCallbacks *callbacks, * void *callback_context); * * DESCRIPTION * * This is optional function which can be used to set specific callbacks * for the packet stream indicated by `stream'. If these are set then * `callbacks' will be used instead of the ones set for the function * silc_packet_engine_start. To reset the normal behaviour call this * function again with `callbacks' as NULL. Note that the responsibility * of handling end of stream, and error conditions moves to the layer * calling this function since the original callbacks set in the * silc_packet_engine_start will not be called. * ***/ void silc_packet_stream_callbacks(SilcPacketStream stream, SilcPacketCallbacks *callbacks, void *callback_context); /****f* silccore/SilcPacketAPI/silc_packet_stream_ref * * SYNOPSIS * * void silc_packet_stream_ref(SilcPacketStream stream); * * DESCRIPTION * * Increase reference counter for the stream indicated by `stream'. This * can be used to take a reference for the stream. To unreference the * stream call silc_packet_stream_unref function. * ***/ void silc_packet_stream_ref(SilcPacketStream stream); /****f* silccore/SilcPacketAPI/silc_packet_stream_unref * * SYNOPSIS * * void silc_packet_stream_unref(SilcPacketStream stream); * * DESCRIPTION * * Decrease reference counter for the stream indicated by `stream'. If * the counter hits zero the stream will be destroyed automatically. * ***/ void silc_packet_stream_unref(SilcPacketStream stream); /****f* silccore/SilcPacketAPI/silc_packet_set_context * * SYNOPSIS * * void silc_packet_set_context(SilcPacketStream stream, void *app_context); * * DESCRIPTION * * Set an application specific context to the stream. The context will * be delivered to all callback functions, and it can be retrieved by * calling silc_packet_get_context function as well. Note that this is * separate packet stream specific context, and not the same as * `callback_context' in silc_packet_engine_start. Both will be delivered * to the callbacks. * ***/ void silc_packet_set_context(SilcPacketStream stream, void *app_context); /****f* silccore/SilcPacketAPI/silc_packet_get_context * * SYNOPSIS * * void *silc_packet_get_context(SilcPacketStream stream); * * DESCRIPTION * * Returns the current set application context, or NULL if none is set. * ***/ void *silc_packet_get_context(SilcPacketStream stream); /****f* silccore/SilcPacketAPI/silc_packet_set_ciphers * * SYNOPSIS * * void silc_packet_set_ciphers(SilcPacketStream stream, SilcCipher send, * SilcCipher receive); * * DESCRIPTION * * Set ciphers to be used to encrypt sent packets, and decrypt received * packets. This can be called multiple times to change the ciphers. * In this case if old cipher is set it will be freed. If ciphers are * not set packets will not be encrypted or decrypted. * ***/ void silc_packet_set_ciphers(SilcPacketStream stream, SilcCipher send, SilcCipher receive); /****f* silccore/SilcPacketAPI/silc_packet_get_ciphers * * SYNOPSIS * * bool silc_packet_get_ciphers(SilcPacketStream stream, SilcCipher *send, * SilcCipher *receive); * * DESCRIPTION * * Returns the pointers of current ciphers from the `stream'. Returns * FALSE if ciphers are not set. * ***/ bool silc_packet_get_ciphers(SilcPacketStream stream, SilcCipher *send, SilcCipher *receive); /****f* silccore/SilcPacketAPI/silc_packet_set_hmacs * * SYNOPSIS * * void silc_packet_set_hmacs(SilcPacketStream stream, SilcHmac send, * SilcHmac receive); * * DESCRIPTION * * Set HMACs to be used to create MACs for sent packets and to check * MAC for received packets. This can be called multiple times to change * the HMACs. In this case if old HMAC is set it will be freed. If * HMACs are not set MACs are not generated or verified for packets. * ***/ void silc_packet_set_hmacs(SilcPacketStream stream, SilcHmac send, SilcHmac receive); /****f* silccore/SilcPacketAPI/silc_packet_get_hmacs * * SYNOPSIS * * bool silc_packet_get_hmacs(SilcPacketStream stream, SilcHmac *send, * SilcHmac *receive); * * DESCRIPTION * * Returns the pointers of current HMACs from the `stream'. Returns * FALSE if HMACs are not set. * ***/ bool silc_packet_get_hmacs(SilcPacketStream stream, SilcHmac *send, SilcHmac *receive); /****f* silccore/SilcPacketAPI/silc_packet_set_ids * * SYNOPSIS * * bool silc_packet_set_ids(SilcPacketStream stream, * SilcIdType src_id_type, const void *src_id * SilcIdType dst_id_type, const void *dst_id); * * DESCRIPTION * * Set the source ID and destinaion ID to be used when sending packets to * this packet stream. The IDs to be used for a packet stream can be * overridden when sending packets. However, if the IDs do not ever change * for the packet stream it is recommended they are set using this function. * In this case they can be omitted when sending packets to the stream. * It is also possible to set only source or destination ID. * ***/ bool silc_packet_set_ids(SilcPacketStream stream, SilcIdType src_id_type, const void *src_id, SilcIdType dst_id_type, const void *dst_id); /****f* silccore/SilcPacketAPI/silc_packet_send * * SYNOPSIS * * bool silc_packet_send(SilcPacketStream stream, * SilcPacketType type, SilcPacketFlags flags, * const unsigned char *data, SilcUInt32 data_len); * * DESCRIPTION * * Send `data' of length of `data_len' to the packet stream indicated by * `stream'. If ciphers and HMACs were set using silc_packet_set_ciphers * and silc_packet_set_hmacs the packet will be encrypted and MAC will be * generated for it. If silc_packet_set_ids was used to set source and * destination ID for the packet stream those IDs are used in the * packet. If IDs have not been set and they need to be provided then * silc_packet_send_ext function should be used. Otherwise, the packet * will not have IDs set at all. * ***/ bool silc_packet_send(SilcPacketStream stream, SilcPacketType type, SilcPacketFlags flags, const unsigned char *data, SilcUInt32 data_len); /****f* silccore/SilcPacketAPI/silc_packet_send_ext * * SYNOPSIS * * bool * silc_packet_send_ext(SilcPacketStream stream, * SilcPacketType type, SilcPacketFlags flags, * SilcIdType src_id_type, void *srd_id, * SilcIdType dst_id_type, void *dst_id, * const unsigned char *data, SilcUInt32 data_len, * SilcCipher cipher, SilcHmac hmac); * * DESCRIPTION * * This function can be used to specificly set different parameters of * the SILC packet to be sent to the stream indicated by `stream'. This * function can be used to set specific IDs, cipher and HMAC to be used * in packet creation. If `truelen' is provided that value is put to the * SILC packet's truelen field, if it is zero the routine will calculate * the truelen field for the packet. If `padlen' is provided that value * will be the length of the padding for the packet, if zero the routine * will calculate necessary amount of padding for the packet. This * function can be used when specific ciphers, HMACs and IDs has not been * set for the stream, or setting them for the stream is not suitable. * ***/ bool silc_packet_send_ext(SilcPacketStream stream, SilcPacketType type, SilcPacketFlags flags, SilcIdType src_id_type, void *src_id, SilcIdType dst_id_type, void *dst_id, const unsigned char *data, SilcUInt32 data_len, SilcCipher cipher, SilcHmac hmac); /****f* silccore/SilcPacketAPI/silc_packet_free * * SYNOPSIS * * void silc_packet_free(SilcPacketEngine engine, SilcPacket packet); * * DESCRIPTION * * This function is used to free the SilcPacket pointer that application * receives in the SilcPacketReceive callback. Application must free * the packet. * ***/ void silc_packet_free(SilcPacketEngine engine, SilcPacket packet); #endif /* SILCPACKET_H */