/*
silcpacket.h
-
- Author: Pekka Riikonen <priikone@poseidon.pspt.fi>
-
- Copyright (C) 1997 - 2000 Pekka Riikonen
-
+
+ Author: Pekka Riikonen <priikone@silcnet.org>
+
+ Copyright (C) 1997 - 2001 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; either version 2 of the License, or
(at your option) any later version.
-
+
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
*/
+/****h* silccore/SilcPacketAPI
+ *
+ * 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
-/* Amount of bytes to be read from the socket connection at once. */
-#define SILC_PACKET_READ_SIZE 16384
-
-/* Default byte size of the packet. This can be set larger if this
- is not enough, we shall see. */
-#define SILC_PACKET_DEFAULT_SIZE 2048
+/* Default byte size of the packet. */
+#define SILC_PACKET_DEFAULT_SIZE SILC_SOCKET_BUF_SIZE
/* Header length without source and destination ID's. */
#define SILC_PACKET_HEADER_LEN 8 + 2
/* Maximum length of ID */
#define SILC_PACKET_MAX_ID_LEN 16
-/* SILC packet type definition. For now, it is defined like this and I don't
- expect it to change in any near future. If one byte as a packet type is
- not enough we can, then, think something else. */
+/****d* silccore/SilcPacketAPI/SilcPacketType
+ *
+ * NAME
+ *
+ * typedef unsigned char SilcPacketType;
+ *
+ * DESCRIPTION
+ *
+ * SILC packet type definition and all the packet types.
+ *
+ * SOURCE
+ */
typedef unsigned char SilcPacketType;
-/* SILC packet version type definition. */
+/* 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_PRIVATE 200 /* Private range start */
+#define SILC_PACKET_MAX 255 /* RESERVED */
+/***/
+
+/****d* silccore/SilcPacketAPI/SilcPacketVersion
+ *
+ * NAME
+ *
+ * typedef unsigned char SilcPacketVersion;
+ *
+ * DESCRIPTION
+ *
+ * SILC packet version type definition.
+ *
+ ***/
typedef unsigned char SilcPacketVersion;
-/* SILC packet flags type definition. */
+/****d* silccore/SilcPacketAPI/SilcPacketFlags
+ *
+ * NAME
+ *
+ * typedef unsigned char SilcPacketFlags;
+ *
+ * DESCRIPTION
+ *
+ * SILC packet flags type definition and all the packet flags.
+ *
+ * SOURCE
+ */
typedef unsigned char SilcPacketFlags;
/* All defined packet flags */
-#define SILC_PACKET_FLAG_NONE 0x00
-#define SILC_PACKET_FLAG_PRIVMSG_KEY 0x01
-#define SILC_PACKET_FLAG_FORWARDED 0x02
-#define SILC_PACKET_FLAG_BROADCAST 0x04
-#define SILC_PACKET_FLAG_TUNNELED 0x08
+#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 */
+/***/
+
/* Rest of flags still available
+#define SILC_PACKET_FLAG_XXX 0x08
#define SILC_PACKET_FLAG_XXX 0x10
#define SILC_PACKET_FLAG_XXX 0x20
#define SILC_PACKET_FLAG_XXX 0x40
#define SILC_PACKET_FLAG_XXX 0x80
*/
-/*
- SILC packet context.
-
- In packet sending this is filled and sent to silc_packet_assemble
- which then uses it to assemble new packet. In packet reception pointer
- to this context is sent to silc_packet_parse which parses the packet
- and returns the relevant information to this structure. On packet
- reception returned ID's are always the hash values of the ID's from
- the packet.
-
- Short description of the fields following:
-
- SilcBuffer buffer
-
- The data buffer.
-
- SilcPacketType type
-
- Type of the packet. Types are defined below.
-
- SilcPacketFlags flags
-
- Packet flags. Flags are defined above.
-
- unsigned char *src_id
- unsigned short src_id_len
- unsigned char src_id_type
-
- Source ID, its length and type. On packet reception retuned ID's
- are always the hash values of the ID's from the packet.
-
- unsigned char *dst_id;
- unsigned short dst_id_len;
- unsigned char src_id_type;
-
- Destination ID, its length and type. On packet reception retuned
- ID's are always the hash values of the ID's from the packet.
-
- SilcHash hash
-
- Pointer to allocated hash object. This must be MD5 hash object.
- This is used to calculate checksum of the packet.
-
-*/
+/****s* silccore/SilcPacketAPI/SilcPacketContext
+ *
+ * NAME
+ *
+ * typedef struct { ... } SilcPacketContext;
+ *
+ * DESCRIPTION
+ *
+ * In packet sending this is filled and sent to silc_packet_assemble
+ * which then uses it to assemble new packet. In packet reception pointer
+ * to this context is sent to silc_packet_parse which parses the packet
+ * and returns the relevant information to this structure. On packet
+ * reception returned ID's are always the hash values of the ID's from
+ * the packet.
+ *
+ * Short description of the fields following:
+ *
+ * SilcBuffer buffer
+ *
+ * The data buffer.
+ *
+ * SilcPacketType type
+ *
+ * Type of the packet. Types are defined below.
+ *
+ * SilcPacketFlags flags
+ *
+ * Packet flags. Flags are defined above.
+ *
+ * unsigned char *src_id
+ * uint16 src_id_len
+ * unsigned char src_id_type
+ *
+ * Source ID, its length and type. On packet reception retuned ID's
+ * are always the hash values of the ID's from the packet.
+ *
+ * unsigned char *dst_id;
+ * uint16 dst_id_len;
+ * unsigned char src_id_type;
+ *
+ * Destination ID, its length and type. On packet reception retuned
+ * ID's are always the hash values of the ID's from the packet.
+ *
+ * uint16 truelen
+ * uint16 padlen
+ *
+ * The true lenght of the packet and the padded length of the packet.
+ * These may be set by the caller before calling any of the
+ * silc_packet_* routines. If not provided the library will calculate
+ * the values.
+ *
+ * int users;
+ *
+ * Reference counter for this context. The context is freed only
+ * after the reference counter hits zero. The counter is added
+ * calling silc_packet_context_dup and decreased by calling the
+ * silc_packet_context_free.
+ *
+ * uint32 sequence;
+ *
+ * Packet sequence number.
+ *
+ ***/
typedef struct {
SilcBuffer buffer;
SilcPacketType type;
SilcPacketFlags flags;
unsigned char *src_id;
- unsigned short src_id_len;
+ uint16 src_id_len;
unsigned char src_id_type;
unsigned char *dst_id;
- unsigned short dst_id_len;
+ uint16 dst_id_len;
unsigned char dst_id_type;
- unsigned short truelen;
- unsigned short padlen;
-
- /* For padding generation */
- SilcRng rng;
+ uint16 truelen;
+ uint16 padlen;
/* Back pointers */
void *context;
SilcSocketConnection sock;
- /* Reference count for this context. The context is free'd only
- after the reference count is zero. */
int users;
-} SilcPacketContext;
-
-/*
- Silc Packet Parser context.
- This context is used in packet reception when silc_packet_receive_process
- function calls parser callback that performs the actual packet decryption
- and parsing. This context is sent as argument to the parser function.
- This context must be free'd by the parser callback function.
-
- Following description of the fields:
-
- SilcPacketContext *packet
-
- The actual packet received from the network. In this phase the
- context is not parsed, only the packet->buffer is allocated and
- it includes the raw packet data, which is encrypted.
-
- SilcSocketConnection sock
-
- The associated connection.
-
- SilcCipher cipher
-
- The cipher to be used in the decryption.
-
- SilcHmac hmac
-
- The HMAC to be used in the decryption.
-
- void *context
-
- User context that is sent to the silc_packet_receive_process
- function. This usually includes application and connection specific
- data.
-
-*/
+ uint32 sequence;
+} SilcPacketContext;
+/****s* silccore/SilcPacketAPI/SilcPacketParserContext
+ *
+ * NAME
+ *
+ * typedef struct { ... } SilcPacketParserContext;
+ *
+ * DESCRIPTION
+ *
+ * This context is used in packet reception when silc_packet_receive_process
+ * function calls parser callback that performs the actual packet decryption
+ * and parsing. This context is sent as argument to the parser function.
+ * This context must be free'd by the parser callback function.
+ *
+ * Following description of the fields:
+ *
+ * SilcPacketContext *packet
+ *
+ * The actual packet received from the network. In this phase the
+ * context is not parsed, only the packet->buffer is allocated and
+ * it includes the raw packet data, which is encrypted.
+ *
+ * SilcSocketConnection sock
+ *
+ * The associated connection.
+ *
+ * void *context
+ *
+ * User context that is sent to the silc_packet_receive_process
+ * function. This usually includes application and connection specific
+ * data.
+ *
+ ***/
typedef struct {
SilcPacketContext *packet;
SilcSocketConnection sock;
- SilcCipher cipher;
- SilcHmac hmac;
void *context;
} SilcPacketParserContext;
-/* The parser callback function. */
+/****f* silccore/SilcPacketAPI/SilcPacketParserCallback
+ *
+ * SYNOPSIS
+ *
+ * typedef void (*SilcPacketParserCallback)(SilcPacketParserContext
+ * *parse_context);
+ *
+ * DESCRIPTION
+ *
+ * This callback is given to the silc_packet_receive_process function.
+ * The callback is called by the library every time a packet is
+ * received from the network. After the packet has been decrypted
+ * and at least partially parsed it is passed to the application
+ * for further parsing using this callback and the SilcPacketParserContext
+ * context. The application receiving the SilcPacketParserContext
+ * must free it.
+ *
+ ***/
typedef void (*SilcPacketParserCallback)(SilcPacketParserContext
*parse_context);
-
-/* 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_ID_LIST 19 /* Sending list of them */
-#define SILC_PACKET_NEW_CLIENT 20 /* Registering client */
-#define SILC_PACKET_NEW_SERVER 21 /* Registering server */
-#define SILC_PACKET_NEW_CHANNEL 22 /* Registering channel */
-#define SILC_PACKET_NEW_CHANNEL_USER 23 /* "" user on channel */
-#define SILC_PACKET_NEW_CHANNEL_LIST 24 /* List of new channels */
-#define SILC_PACKET_NEW_CHANNEL_USER_LIST 25 /* List of users on "" */
-#define SILC_PACKET_REPLACE_ID 26 /* To replace old ID */
-#define SILC_PACKET_REMOVE_ID 27 /* To remove ID */
-#define SILC_PACKET_REMOVE_CHANNEL_USER 28 /* Remove user from channel */
-#define SILC_PACKET_REKEY 29
-#define SILC_PACKET_REKEY_DONE 30
-/* #define SILC_PACKET_MAX 255 */
+/****f* silccore/SilcPacketAPI/SilcPacketCheckDecrypt
+ *
+ * SYNOPSIS
+ *
+ * typedef int (*SilcPacketCheckDecrypt)(SilcPacketType packet_type,
+ * SilcBuffer buffer,
+ * SilcPacketContext *packet,
+ * void *context);
+ *
+ * DESCRIPTION
+ *
+ * This callback function relates to the checking whether the packet is
+ * normal packet or special packet and how it should be processed. If
+ * the callback returns TRUE the packet is normal and FALSE if the packet
+ * is special and requires special procesing. Some of the packets in
+ * SILC are special (like channel message packets that are encrypted
+ * using channel specific keys) and requires special processing. That
+ * is the reason for this callback function.
+ *
+ * The library will call this function if provided for the
+ * silc_packet_decrypt function. The `packet_type' is the type of
+ * packet received (this is also actually the first time application
+ * receives information of the received packet, next time it receives
+ * it is when the SilcPacketParserCallback function is called),
+ * the `buffer' is the raw packet data the `packet' the allocated
+ * SilcPacketContext that is filled when parsing the packet and `context'
+ * is application specific user context.
+ *
+ ***/
+typedef int (*SilcPacketCheckDecrypt)(SilcPacketType packet_type,
+ SilcBuffer buffer,
+ SilcPacketContext *packet,
+ void *context);
/* Macros */
-/* Returns true length of the packet and padded length of the packet */
+/****d* silccore/SilcPacketAPI/SILC_PACKET_LENGTH
+ *
+ * NAME
+ *
+ * #define SILC_PACKET_LENGTH ...
+ *
+ * DESCRIPTION
+ *
+ * Returns true length of the packet and padded length of the packet.
+ * This is primarily used by the libary in packet parsing phase but
+ * the application may use it as well if needed.
+ *
+ * SOURCE
+ */
#define SILC_PACKET_LENGTH(__packet, __ret_truelen, __ret_padlen) \
do { \
SILC_GET16_MSB((__ret_truelen), (__packet)->data); \
(__ret_padlen) = (((__ret_truelen) - 2) + \
SILC_PACKET_MAX_PADLEN) & ~(SILC_PACKET_MAX_PADLEN - 1); \
} while(0)
-
-/* Returns pad length of the packet */
+/***/
+
+/****d* silccore/SilcPacketAPI/SILC_PACKET_PADLEN
+ *
+ * NAME
+ *
+ * #define SILC_PACKET_PADLEN ...
+ *
+ * DESCRIPTION
+ *
+ * Returns the length of the padding in the packet. This is used
+ * by various library routines to determine needed padding length.
+ *
+ * SOURCE
+ */
#define SILC_PACKET_PADLEN(__packetlen) \
SILC_PACKET_MAX_PADLEN - ((__packetlen) - 2) % SILC_PACKET_MAX_PADLEN;
+/***/
/* Prototypes */
+
+/****f* silccore/SilcPacketAPI/silc_packet_write
+ *
+ * SYNOPSIS
+ *
+ * int silc_packet_write(int sock, SilcBuffer src);
+ *
+ * DESCRIPTION
+ *
+ * Writes data from encrypted buffer to the socket connection. If the
+ * data cannot be written at once, it will be written later with a timeout.
+ * The data is written from the data section of the buffer, not from head
+ * or tail section. This automatically pulls the data section towards end
+ * after writing the data.
+ *
+ ***/
int silc_packet_write(int sock, SilcBuffer src);
+
+/****f* silccore/SilcPacketAPI/silc_packet_send
+ *
+ * SYNOPSIS
+ *
+ * int silc_packet_send(SilcSocketConnection sock, int force_send);
+ *
+ * DESCRIPTION
+ *
+ * Actually sends the packet. This flushes the connections outgoing data
+ * buffer. If data is sent directly to the network this returns the bytes
+ * written, if error occured this returns -1 and if the data could not
+ * be written directly to the network at this time this returns -2, in
+ * which case the data should be queued by the caller and sent at some
+ * later time. If `force_send' is TRUE this attempts to write the data
+ * directly to the network, if FALSE, this returns -2.
+ *
+ ***/
int silc_packet_send(SilcSocketConnection sock, int force_send);
+
+/****f* silccore/SilcPacketAPI/silc_packet_encrypt
+ *
+ * SYNOPSIS
+ *
+ * void silc_packet_encrypt(SilcCipher cipher, SilcHmac hmac,
+ * SilcBuffer buffer, uint32 len);
+ *
+ * DESCRIPTION
+ *
+ * Encrypts a packet. This also creates HMAC of the packet before
+ * encryption and adds the HMAC at the end of the buffer. This assumes
+ * that there is enough free space at the end of the buffer to add the
+ * computed HMAC. This is the normal way of encrypting packets, if some
+ * other process of HMAC computing and encryption is needed this function
+ * cannot be used.
+ *
+ ***/
void silc_packet_encrypt(SilcCipher cipher, SilcHmac hmac,
- SilcBuffer buffer, unsigned int len);
+ SilcBuffer buffer, uint32 len);
+
+/****f* silccore/SilcPacketAPI/silc_packet_assemble
+ *
+ * SYNOPSIS
+ *
+ * void silc_packet_assemble(SilcPacketContext *ctx);
+ *
+ * DESCRIPTION
+ *
+ * Assembles a new packet to be ready for send out. The buffer sent as
+ * argument must include the data to be sent and it must not be encrypted.
+ * The packet also must have enough free space so that the SILC header
+ * and padding maybe added to the packet. The packet is encrypted after
+ * this function has returned.
+ *
+ * The buffer sent as argument should be something like following:
+ *
+ * --------------------------------------------
+ * | head | data | tail |
+ * --------------------------------------------
+ * ^ ^
+ * 58 bytes x bytes
+ *
+ * So that the SILC header and 1 - 16 bytes of padding can fit to
+ * the buffer. After assembly the buffer might look like this:
+ *
+ * --------------------------------------------
+ * | data | |
+ * --------------------------------------------
+ * ^ ^
+ * Start of assembled packet
+ *
+ * Packet construct is as follows (* = won't be encrypted):
+ *
+ * n bytes SILC Header
+ * 2 bytes Payload length (*)
+ * 1 byte Flags
+ * 1 byte Packet type
+ * 2 bytes Source ID Length
+ * 2 bytes Destination ID Length
+ * 1 byte Source ID Type
+ * n bytes Source ID
+ * 1 byte Destination ID Type
+ * n bytes Destination ID
+ *
+ * 1 - 16 bytes Padding
+ *
+ * n bytes Data payload
+ *
+ * All fields in the packet will be authenticated by MAC. The MAC is
+ * not computed here, it must be computed separately before encrypting
+ * the packet.
+ *
+ ***/
void silc_packet_assemble(SilcPacketContext *ctx);
+
+/****f* silccore/SilcPacketAPI/silc_packet_send_prepare
+ *
+ * SYNOPSIS
+ *
+ * void silc_packet_send_prepare(SilcSocketConnection sock,
+ * uint32 header_len,
+ * uint32 padlen,
+ * uint32 data_len);
+ *
+ * DESCRIPTION
+ *
+ * Prepare outgoing data buffer for packet sending. This moves the data
+ * area so that new packet may be added into it. If needed this allocates
+ * more space to the buffer. This handles directly the connection's
+ * outgoing buffer in SilcSocketConnection object.
+ *
+ ***/
void silc_packet_send_prepare(SilcSocketConnection sock,
- unsigned int header_len,
- unsigned int padlen,
- unsigned int data_len);
-int silc_packet_read(int sock, SilcBuffer dest);
+ uint32 header_len,
+ uint32 padlen,
+ uint32 data_len);
+
+/****f* silccore/SilcPacketAPI/silc_packet_read
+ *
+ * SYNOPSIS
+ *
+ * int silc_packet_read(int fd, SilcSocketConnection sock);
+ *
+ * DESCRIPTION
+ *
+ * Reads data from the socket connection into the incoming data buffer.
+ * However, this does not parse the packet, it only reads some amount from
+ * the network. If there are more data available that can be read at a time
+ * the rest of the data will be read later with a timeout and only after
+ * that the packet is ready to be parsed.
+ *
+ * The destination buffer sent as argument must be initialized before
+ * calling this function, and, the data section and the start of the tail
+ * section must be same. Ie. we add the read data to the tail section of
+ * the buffer hence the data section is the start of the buffer.
+ *
+ * This returns amount of bytes read or -1 on error or -2 on case where
+ * all of the data could not be read at once.
+ *
+ ***/
+int silc_packet_read(int fd, SilcSocketConnection sock);
+
+/****f* silccore/SilcPacketAPI/silc_packet_receive
+ *
+ * SYNOPSIS
+ *
+ * int silc_packet_receive(SilcSocketConnection sock);
+ *
+ * DESCRIPTION
+ *
+ * Receives packet from network and reads the data into connection's
+ * incoming data buffer. If the data was read directly this returns the
+ * read bytes, if error occured this returns -1, if the data could not
+ * be read directly at this time this returns -2 in which case the data
+ * should be read again at some later time, or If EOF occured this returns
+ * 0.
+ *
+ ***/
int silc_packet_receive(SilcSocketConnection sock);
+
+/****f* silccore/SilcPacketAPI/silc_packet_decrypt
+ *
+ * SYNOPSIS
+ *
+ * int silc_packet_decrypt(SilcCipher cipher, SilcHmac hmac,
+ * SilcBuffer buffer, SilcPacketContext *packet,
+ * SilcPacketCheckDecrypt check_packet,
+ * void *context);
+ *
+ * DESCRIPTION
+ *
+ * Decrypts a packet. This assumes that typical SILC packet is the
+ * packet to be decrypted and thus checks for normal and special SILC
+ * packets and can handle both of them. This also computes and checks
+ * the HMAC of the packet. If any other special or customized decryption
+ * processing is required this function cannot be used. This returns
+ * -1 on error, 0 when packet is normal packet and 1 when the packet
+ * is special and requires special processing.
+ *
+ * The `check_packet' is a callback funtion that this function will
+ * call. The callback relates to the checking whether the packet is
+ * normal packet or special packet and how it should be processed. If
+ * the callback return TRUE the packet is normal and FALSE if the packet
+ * is special and requires special procesing.
+ *
+ ***/
int silc_packet_decrypt(SilcCipher cipher, SilcHmac hmac,
- SilcBuffer buffer, SilcPacketContext *packet);
+ SilcBuffer buffer, SilcPacketContext *packet,
+ SilcPacketCheckDecrypt check_packet,
+ void *context);
+
+/****f* silccore/SilcPacketAPI/silc_packet_receive_process
+ *
+ * SYNOPSIS
+ *
+ * void silc_packet_receive_process(SilcSocketConnection sock,
+ * SilcCipher cipher, SilcHmac hmac,
+ * SilcPacketParserCallback parser,
+ * void *context);
+ *
+ * DESCRIPTION
+ *
+ * Processes the received data. This checks the received data and
+ * calls parser callback that handles the actual packet decryption
+ * and parsing. If more than one packet was received this calls the
+ * parser multiple times. The parser callback will get context
+ * SilcPacketParserContext that includes the packet and the `context'
+ * sent to this function.
+ *
+ ***/
void silc_packet_receive_process(SilcSocketConnection sock,
SilcCipher cipher, SilcHmac hmac,
SilcPacketParserCallback parser,
void *context);
+
+/****f* silccore/SilcPacketAPI/silc_packet_parse
+ *
+ * SYNOPSIS
+ *
+ * SilcPacketType silc_packet_parse(SilcPacketContext *ctx);
+ *
+ * DESCRIPTION
+ *
+ * Parses the packet. This is called when a whole packet is ready to be
+ * parsed. The buffer sent must be already decrypted before calling this
+ * function. The len argument must be the true length of the packet. This
+ * function returns the type of the packet. The data section of the
+ * buffer is parsed, not head or tail sections.
+ *
+ ***/
SilcPacketType silc_packet_parse(SilcPacketContext *ctx);
+
+/****f* silccore/SilcPacketAPI/silc_packet_parse_special
+ *
+ * SYNOPSIS
+ *
+ * SilcPacketType silc_packet_parse_special(SilcPacketContext *ctx);
+ *
+ * DESCRIPTION
+ *
+ * Perform special SILC Packet header parsing. This is required to some
+ * packet types that have the data payload encrypted with different key
+ * than the header area plus padding of the packet. Hence, this parses
+ * the header in a way that it does not take the data area into account
+ * and parses the header and padding area only.
+ *
+ ***/
SilcPacketType silc_packet_parse_special(SilcPacketContext *ctx);
+
+/****f* silccore/SilcPacketAPI/silc_packet_context_alloc
+ *
+ * SYNOPSIS
+ *
+ * SilcPacketContext *silc_packet_context_alloc();
+ *
+ * DESCRIPTION
+ *
+ * Allocates a packet context. Packet contexts are used when
+ * packets are assembled and parsed. The context is freed by the
+ * silc_packet_context_free function.
+ *
+ ***/
SilcPacketContext *silc_packet_context_alloc();
+
+/****f* silccore/SilcPacketAPI/silc_packet_context_dup
+ *
+ * SYNOPSIS
+ *
+ * SilcPacketContext *silc_packet_context_dup(SilcPacketContext *ctx);
+ *
+ * DESCRIPTION
+ *
+ * Duplicates the packet context. It actually does not duplicate
+ * any data, instead a reference counter is increased.
+ *
+ ***/
SilcPacketContext *silc_packet_context_dup(SilcPacketContext *ctx);
+
+/****f* silccore/SilcPacketAPI/silc_packet_context_free
+ *
+ * SYNOPSIS
+ *
+ * void silc_packet_context_free(SilcPacketContext *ctx);
+ *
+ * DESCRIPTION
+ *
+ * Frees the packet context. The context is actually freed when the
+ * reference counter hits zero.
+ *
+ ***/
void silc_packet_context_free(SilcPacketContext *ctx);
#endif
projects / silc.git / blobdiff