Added support for SID with IV Included flag. Added
[silc.git] / lib / silccore / silcpacket.h
index fce2ebf5e5d7883596ec2237c4510114b85e39e7..4eb8799e113d9a5db217dded07e5308848340179 100644 (file)
@@ -4,7 +4,7 @@
 
   Author: Pekka Riikonen <priikone@silcnet.org>
 
-  Copyright (C) 1997 - 2005 Pekka Riikonen
+  Copyright (C) 1997 - 2006 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
  *
  * 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.
+ * The SILC secure binary packet protocol interface, provides interface for
+ * sending and receiving SILC packets.  The interface provides a packet
+ * engine, that can be used to receive packets from packet streams, and
+ * routines for sending all kinds of SILC packets.
+ *
+ * The packet engine and packet stream are thread safe.  They can be safely
+ * used in multi threaded environment.
  *
  ***/
 
@@ -54,7 +57,6 @@
 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 */
@@ -86,6 +88,9 @@ typedef SilcUInt8 SilcPacketType;
 
 #define SILC_PACKET_PRIVATE              200     /* Private range start  */
 #define SILC_PACKET_MAX                  255     /* RESERVED */
+
+#define SILC_PACKET_NONE                0       /* RESERVED */
+#define SILC_PACKET_ANY                  0
 /***/
 
 /****d* silccore/SilcPacketAPI/SilcPacketFlags
@@ -153,21 +158,25 @@ typedef struct SilcPacketStreamStruct *SilcPacketStream;
  *    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.
+ *    silc_packet_free function if it takes it in for processing.
+ *
+ *    The list pointer `next' can be used by the application to put the
+ *    packet context in a list during processing, if needed.
  *
  * 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 */
+  struct SilcPacketStruct *next;     /* List pointer, application may set */
+  SilcPacketStream stream;          /* Packet stream this packet is from */
+  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;
 /***/
 
@@ -181,7 +190,8 @@ typedef struct SilcPacketStruct {
  *
  *    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.
+ *    from the actual stream.  It can retrieve the underlaying stream from
+ *    the packet stream by calling silc_packet_stream_get_stream function.
  *
  * SOURCE
  */
@@ -190,6 +200,7 @@ typedef enum {
   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_UNKNOWN_SID,          /* Unknown SID (with IV included) */
   SILC_PACKET_ERR_MALFORMED,            /* Packet is malformed */
   SILC_PACKET_ERR_NO_MEMORY,            /* System out of memory */
 } SilcPacketError;
@@ -199,25 +210,54 @@ typedef enum {
  *
  * SYNOPSIS
  *
- *    typedef void (*SilcPacketReceiveCb)(SilcPacketEngine engine,
- *                                        SilcPacketStream stream,
- *                                        SilcPacket packet,
- *                                        void *callback_context,
- *                                        void *app_context);
+ *    typedef SilcBool (*SilcPacketReceiveCb)(SilcPacketEngine engine,
+ *                                            SilcPacketStream stream,
+ *                                            SilcPacket packet,
+ *                                            void *callback_context,
+ *                                            void *stream_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.
+ *    SilcPacket with silc_packet_free if it takes the packet in for
+ *    processing.  This callback is set in the SilcPacketCallbacks structure.
+ *    The `callback_context' is the context set as argument in the
+ *    silc_packet_engine_start function.  The `stream_context' is stream
+ *    specific context that was set by calling silc_packet_set_context.
+ *
+ *    If the application takes the received packet `packet' into processing
+ *    TRUE must be returned.  If FALSE is returned the packet engine will
+ *    pass the packet to other packet processor, if one has been linked
+ *    to the stream with silc_packet_stream_link function.  If no extra
+ *    processor is linked the packet is dropped.
+ *
+ * EXAMPLE
+ *
+ *    SilcBool
+ *    silc_foo_packet_receive_cb(SilcPacketEngine engine,
+ *                               SilcPacketStream stream, SilcPacket packet,
+ *                               void *callback_context, void *stream_context)
+ *    {
+ *      Application ctx = callback_context;
+ *
+ *      // If we're not up yet, let's not process the packet
+ *      if (ctx->initialized == FALSE)
+ *        return FALSE;
+ *
+ *      // Process the incoming packet...
+ *      ...
+ *
+ *      // It's our packet now, no one else will get it
+ *      return TRUE;
+ *    }
  *
  ***/
-typedef void (*SilcPacketReceiveCb)(SilcPacketEngine engine,
-                                   SilcPacketStream stream,
-                                   SilcPacket packet,
-                                   void *callback_context,
-                                   void *app_context);
+typedef SilcBool (*SilcPacketReceiveCb)(SilcPacketEngine engine,
+                                       SilcPacketStream stream,
+                                       SilcPacket packet,
+                                       void *callback_context,
+                                       void *stream_context);
 
 /****f* silccore/SilcPacketAPI/SilcPacketEosCb
  *
@@ -226,7 +266,7 @@ typedef void (*SilcPacketReceiveCb)(SilcPacketEngine engine,
  *    typedef void (*SilcPacketEosCb)(SilcPacketEngine engine,
  *                                    SilcPacketStream stream,
  *                                    void *callback_context,
- *                                    void *app_context);
+ *                                    void *stream_context);
  *
  * DESCRIPTION
  *
@@ -240,7 +280,7 @@ typedef void (*SilcPacketReceiveCb)(SilcPacketEngine engine,
 typedef void (*SilcPacketEosCb)(SilcPacketEngine engine,
                                SilcPacketStream stream,
                                void *callback_context,
-                               void *app_context);
+                               void *stream_context);
 
 /****f* silccore/SilcPacketAPI/SilcPacketErrorCb
  *
@@ -250,7 +290,7 @@ typedef void (*SilcPacketEosCb)(SilcPacketEngine engine,
  *                                      SilcPacketStream stream,
  *                                      SilcPacketError error,
  *                                      void *callback_context,
- *                                      void *app_context);
+ *                                      void *stream_context);
  *
  * DESCRIPTION
  *
@@ -263,7 +303,7 @@ typedef void (*SilcPacketErrorCb)(SilcPacketEngine engine,
                                  SilcPacketStream stream,
                                  SilcPacketError error,
                                  void *callback_context,
-                                 void *app_context);
+                                 void *stream_context);
 
 /****s* silccore/SilcPacketAPI/SilcPacketStream
  *
@@ -294,30 +334,27 @@ typedef struct {
  * SYNOPSIS
  *
  *    SilcPacketEngine
- *    silc_packet_engine_start(SilcSchedule schedule, SilcRng rng, bool router,
+ *    silc_packet_engine_start(SilcRng rng, SilcBool 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
+ *    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.
+ *    The packet engine is thread safe.  You can use one packet engine in
+ *    multi threaded application.
  *
  ***/
 SilcPacketEngine
-silc_packet_engine_start(SilcSchedule schedule, SilcRng rng, bool router,
+silc_packet_engine_start(SilcRng rng, SilcBool router,
                         SilcPacketCallbacks *callbacks,
                         void *callback_context);
 
@@ -340,6 +377,7 @@ void silc_packet_engine_stop(SilcPacketEngine engine);
  * SYNOPSIS
  *
  *    SilcPacketStream silc_packet_stream_create(SilcPacketEngine engine,
+ *                                               SilcSchedule schedule,
  *                                               SilcStream stream);
  *
  * DESCRIPTION
@@ -357,16 +395,12 @@ void silc_packet_engine_stop(SilcPacketEngine engine);
  *    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.
+ *    The SilcPacketStream is thread safe.  Same context can be safely used
+ *    in multi threaded environment.
  *
  ***/
 SilcPacketStream silc_packet_stream_create(SilcPacketEngine engine,
+                                          SilcSchedule schedule,
                                           SilcStream stream);
 
 /****f* silccore/SilcPacketAPI/silc_packet_stream_destroy
@@ -383,58 +417,43 @@ SilcPacketStream silc_packet_stream_create(SilcPacketEngine engine,
  ***/
 void silc_packet_stream_destroy(SilcPacketStream stream);
 
-/****f* silccore/SilcPacketAPI/silc_packet_streamer_create
+/****f* silccore/SilcPacketAPI/silc_packet_stream_set_router
  *
  * SYNOPSIS
  *
- *    SilcStream silc_packet_streamer_create(SilcPacketStream stream,
- *                                           SilcPacketType packet_type,
- *                                           SilcPacketFlags packet_flags);
+ *    void silc_packet_stream_set_router(SilcPacketStream stream);
  *
  * 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.
+ *    When called sets the stream indicates by `stream' as SILC router
+ *    connection stream.  This causes that certain packets are handled
+ *    differently.  This must be called for router connection streams and
+ *    must not be called for any other stream.
  *
  ***/
-SilcStream silc_packet_streamer_create(SilcPacketStream stream,
-                                      SilcPacketType packet_type,
-                                      SilcPacketFlags packet_flags);
+void silc_packet_stream_set_router(SilcPacketStream stream);
 
-/****f* silccore/SilcPacketAPI/silc_packet_streamer_destroy
+/****f* silccore/SilcPacketAPI/silc_packet_stream_set_iv_included
  *
  * SYNOPSIS
  *
- *    void silc_packet_streamer_destroy(SilcStream stream);
+ *    void silc_packet_stream_set_iv_included(SilcPacketStream 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.
+ *    Sets an IV Included property for the stream indicated by `stream'.
+ *    This means that the IV used in the encryption will be included in
+ *    the resulted ciphertext.  This makes it possible to send and receive
+ *    packets on unreliable network transport protocol, such as UDP/IP.
+ *    This must be called if the underlaying stream in the `stream' is UDP
+ *    stream.
+ *
+ *    When this is set to the stream the silc_packet_set_sid must be called
+ *    to set new Security ID.  The Security ID will be included with the IV
+ *    in the ciphertext.
  *
  ***/
-void silc_packet_streamer_destroy(SilcStream stream);
+void silc_packet_stream_set_iv_included(SilcPacketStream stream);
 
 /****f* silccore/SilcPacketAPI/silc_packet_stream_get_stream
  *
@@ -447,36 +466,76 @@ void silc_packet_streamer_destroy(SilcStream stream);
  *    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
+ *    This function could 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
+/****f* silccore/SilcPacketAPI/silc_packet_stream_link
  *
  * SYNOPSIS
  *
- *    void silc_packet_stream_callbacks(SilcPacketStream stream,
- *                                      SilcPacketCallbacks *callbacks,
- *                                      void *callback_context);
+ *    SilcBool silc_packet_stream_link(SilcPacketStream stream,
+ *                                     SilcPacketCallbacks *callbacks,
+ *                                     void *callback_context,
+ *                                     int priority, ...);
  *
  * 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.
+ *    Links the packet processing callbacks indicated by `callbacks' into
+ *    the packet stream indicated by `stream' with priority `priority' for
+ *    the packet types given in the variable argument list.  This function
+ *    can be used to link to the packet stream for specific packet types
+ *    and receive them in the specified callbacks.  This way, a third party,
+ *    for example some library may attach itself into the packet stream
+ *    and receive and process certain packets.  The variable argument
+ *    list is ended with -1.  To link to receive all packets use
+ *    SILC_PACKET_ANY.
+ *
+ *    The default packet processing callbacks given as argument to the
+ *    silc_packet_engine_start has the priority 0.  Any priority higher
+ *    than 0 will then take precedence over the default callbacks.  Any
+ *    priority lower than 0 (negative value) will be processed after the
+ *    default callbacks.
+ *
+ *    Note that setting only the 'packet_receive' callback in the `callbacks'
+ *    is required.
+ *
+ * EXAMPLE
+ *
+ *    // Link to this packet stream, with high priority, for
+ *    // SILC_PACKET_CONNECTION_AUTH and SILC_PACKET_CONNECTION_AUTH_REQUEST
+ *    // packets. We don't care about other packets.
+ *    silc_packet_stream_link(stream, our_callbacks, our_context,
+ *                            1000000, SILC_PACKET_CONNECTION_AUTH,
+ *                            SILC_PACKET_CONNECTION_AUTH_REQUEST, -1);
  *
  ***/
-void silc_packet_stream_callbacks(SilcPacketStream stream,
-                                 SilcPacketCallbacks *callbacks,
-                                 void *callback_context);
+SilcBool silc_packet_stream_link(SilcPacketStream stream,
+                                SilcPacketCallbacks *callbacks,
+                                void *callback_context,
+                                int priority, ...);
+
+/****f* silccore/SilcPacketAPI/silc_packet_stream_unlink
+ *
+ * SYNOPSIS
+ *
+ *    void silc_packet_stream_unlink(SilcPacketStream stream,
+ *                                   SilcPacketCallbacks *callbacks,
+ *                                   void *callback_context);
+ *
+ * DESCRIPTION
+ *
+ *    Unlinks the `callbacks' with `callback_context' from the packet stream
+ *    indicated by `stream'.  This function must be called for the callbacks
+ *    that was linked to `stream' when they are not needed anymore.
+ *
+ ***/
+void silc_packet_stream_unlink(SilcPacketStream stream,
+                              SilcPacketCallbacks *callbacks,
+                              void *callback_context);
 
 /****f* silccore/SilcPacketAPI/silc_packet_stream_ref
  *
@@ -507,23 +566,37 @@ void silc_packet_stream_ref(SilcPacketStream stream);
  ***/
 void silc_packet_stream_unref(SilcPacketStream stream);
 
+/****f* silccore/SilcPacketAPI/silc_packet_get_engine
+ *
+ * SYNOPSIS
+ *
+ *    SilcPacketEngine silc_packet_get_engine(SilcPacketStream stream);
+ *
+ * DESCRIPTION
+ *
+ *    Returns the packet engine from the `stream'.
+ *
+ ***/
+SilcPacketEngine silc_packet_get_engine(SilcPacketStream stream);
+
 /****f* silccore/SilcPacketAPI/silc_packet_set_context
  *
  * SYNOPSIS
  *
- *    void silc_packet_set_context(SilcPacketStream stream, void *app_context);
+ *    void silc_packet_set_context(SilcPacketStream stream,
+ *                                 void *stream_context);
  *
  * DESCRIPTION
  *
- *    Set an application specific context to the stream.  The context will
+ *    Sets a stream 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.
+ *    to the callbacks, and this context as the `stream_context' argument.
  *
  ***/
-void silc_packet_set_context(SilcPacketStream stream, void *app_context);
+void silc_packet_set_context(SilcPacketStream stream, void *stream_context);
 
 /****f* silccore/SilcPacketAPI/silc_packet_get_context
  *
@@ -560,8 +633,9 @@ void silc_packet_set_ciphers(SilcPacketStream stream, SilcCipher send,
  *
  * SYNOPSIS
  *
- *    bool silc_packet_get_ciphers(SilcPacketStream stream, SilcCipher *send,
- *                                 SilcCipher *receive);
+ *    SilcBool silc_packet_get_ciphers(SilcPacketStream stream,
+ *                                     SilcCipher *send,
+ *                                     SilcCipher *receive);
  *
  * DESCRIPTION
  *
@@ -569,8 +643,8 @@ void silc_packet_set_ciphers(SilcPacketStream stream, SilcCipher send,
  *    FALSE if ciphers are not set.
  *
  ***/
-bool silc_packet_get_ciphers(SilcPacketStream stream, SilcCipher *send,
-                            SilcCipher *receive);
+SilcBool silc_packet_get_ciphers(SilcPacketStream stream, SilcCipher *send,
+                                SilcCipher *receive);
 
 /****f* silccore/SilcPacketAPI/silc_packet_set_hmacs
  *
@@ -594,8 +668,8 @@ void silc_packet_set_hmacs(SilcPacketStream stream, SilcHmac send,
  *
  * SYNOPSIS
  *
- *    bool silc_packet_get_hmacs(SilcPacketStream stream, SilcHmac *send,
- *                               SilcHmac *receive);
+ *    SilcBool silc_packet_get_hmacs(SilcPacketStream stream, SilcHmac *send,
+ *                                   SilcHmac *receive);
  *
  * DESCRIPTION
  *
@@ -603,16 +677,16 @@ void silc_packet_set_hmacs(SilcPacketStream stream, SilcHmac send,
  *    FALSE if HMACs are not set.
  *
  ***/
-bool silc_packet_get_hmacs(SilcPacketStream stream, SilcHmac *send,
-                          SilcHmac *receive);
+SilcBool 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);
+ *    SilcBool silc_packet_set_ids(SilcPacketStream stream,
+ *                                 SilcIdType src_id_type, const void *src_id
+ *                                 SilcIdType dst_id_type, const void *dst_id);
  *
  * DESCRIPTION
  *
@@ -624,39 +698,64 @@ bool silc_packet_get_hmacs(SilcPacketStream stream, SilcHmac *send,
  *    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);
+SilcBool 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_set_sid
+ *
+ * SYNOPSIS
+ *
+ *    SilcBool silc_packet_set_sid(SilcPacketStream stream, SilcUInt8 sid);
+ *
+ * DESCRIPTION
+ *
+ *    Sets new Security ID to the packet stream indicated by `stream'.  This
+ *    is called only if the IV Included property was set to the stream
+ *    by calling silc_packet_stream_set_iv_included.  This function sets
+ *    new Security ID to the stream which is then included in the ciphertext
+ *    of a packet.  The `sid' must be 0 when it is set for the very first
+ *    time and must be increased by one after each rekey.  This function must
+ *    be called every time new keys are added to the stream after a rekey.
+ *
+ *    If this function is called when the IV Included property has not been
+ *    set to the stream the `sid' will be ignored.  Returns FALSE if the
+ *    IV Included has not been set, TRUE otherwise.
+ *
+ ***/
+SilcBool silc_packet_set_sid(SilcPacketStream stream, SilcUInt8 sid);
 
 /****f* silccore/SilcPacketAPI/silc_packet_send
  *
  * SYNOPSIS
  *
- *    bool silc_packet_send(SilcPacketStream stream,
- *                          SilcPacketType type, SilcPacketFlags flags,
- *                          const unsigned char *data, SilcUInt32 data_len);
+ *    SilcBool 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
+ *    computed 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.
+ *    will not have IDs set at all.  Returns FALSE if packet could not be
+ *    sent.
  *
  ***/
-bool silc_packet_send(SilcPacketStream stream,
-                     SilcPacketType type, SilcPacketFlags flags,
-                     const unsigned char *data, SilcUInt32 data_len);
+SilcBool 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
+ *    SilcBool
  *    silc_packet_send_ext(SilcPacketStream stream,
  *                         SilcPacketType type, SilcPacketFlags flags,
  *                         SilcIdType src_id_type, void *srd_id,
@@ -666,38 +765,134 @@ bool silc_packet_send(SilcPacketStream stream,
  *
  * 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.
+ *    Same as silc_packet_send but with this function different sending
+ *    parameters can be sent as argument.  This function can be used to
+ *    set specific IDs, cipher and HMAC to be used in packet sending,
+ *    instead of the ones saved in the `stream'.  If any of the extra
+ *    pointers are NULL, default values set to the stream will apply.
  *
  ***/
-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);
+SilcBool 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_wait
+ *
+ * SYNOPSIS
+ *
+ *    void *silc_packet_wait_init(SilcPacketStream stream, ...);
+ *
+ * DESCRIPTION
+ *
+ *    Initializes a packet waiter for the packet stream `stream' and
+ *    for the variable argument list of packet types.  The function
+ *    silc_packet_wait can be used to block the thread until a packet
+ *    has been received.  This function is used to initialize the waiting
+ *    and to give the list of packet types that caller wish to receive.
+ *    The variable argument list must end with -1.  To receive all
+ *    packets use SILC_PACKET_ANY.  Returns a context that must be given
+ *    to the silc_packet_wait function as argument.  Returns NULL on
+ *    error.  To uninitialize the waiting call silc_packet_wait_uninit.
+ *
+ * NOTES
+ *
+ *    Note that packets may be available immediately after calling this
+ *    function and they will be buffered, until silc_packet_wait is called.
+ *
+ * EXAMPLE
+ *
+ *    void *waiter;
+ *
+ *    // Will wait for private message packets
+ *    waiter = silc_packet_wait_init(stream,
+ *                                   SILC_PACKET_PRIVATE_MESSAGE, -1);
+ *
+ *
+ ***/
+void *silc_packet_wait_init(SilcPacketStream stream, ...);
+
+/****f* silccore/SilcPacketAPI/silc_packet_wait
+ *
+ * SYNOPSIS
+ *
+ *    void silc_packet_wait_uninit(void *waiter, SilcPacketStream stream);
+ *
+ * DESCRIPTION
+ *
+ *    Uninitializes the waiting context.  This may be called also from
+ *    another thread while other thread is waiting for packets.  This will
+ *    inform the waiting thread to stop waiting.
+ *
+ ***/
+void silc_packet_wait_uninit(void *waiter, SilcPacketStream stream);
+
+/****f* silccore/SilcPacketAPI/silc_packet_wait
+ *
+ * SYNOPSIS
+ *
+ *    int silc_packet_wait(void *waiter, int timeout,
+ *                         SilcPacket *return_packet)
+ *
+ * DESCRIPTION
+ *
+ *    A special function that can be used to wait for a packet to arrive.
+ *    This function will block the calling process or thread until either
+ *    a packet is received into the `return_packet' pointer or the specified
+ *    timeout value `timeout', which is in milliseconds, will expire.  If
+ *    the timeout is 0, no timeout exist.  Before calling this function the
+ *    silc_packet_wait_init must be called.  The caller is responsible for
+ *    freeing the returned packet with silc_packet_free.
+ *
+ *    This function can be used for example from a thread that wants to
+ *    block until SILC packet has been received.
+ *
+ *    Returns 1 when packet was received, 0 if timeout occurred and -1 if
+ *    error occurred.
+ *
+ * EXAMPLE
+ *
+ *    static int foo_read_data(FooContext c)
+ *    {
+ *      SilcPacket packet;
+ *      void *waiter;
+ *      ...
+ *
+ *      // Will wait for private message packets
+ *      if (c->initialized == FALSE) {
+ *        waiter = silc_packet_wait_init(stream,
+ *                                       SILC_PACKET_PRIVATE_MESSAGE, -1);
+ *        c->initialized = TRUE;
+ *      }
+ *
+ *      ...
+ *      // Wait here until private message packet is received
+ *      if ((silc_packet_wait(waiter, 0, &packet)) < 0)
+ *        return -1;
+ *
+ *      ... process packet ...
+ *
+ *      return 1;
+ *    }
+ *
+ ***/
+int silc_packet_wait(void *waiter, int timeout, SilcPacket *return_packet);
 
 /****f* silccore/SilcPacketAPI/silc_packet_free
  *
  * SYNOPSIS
  *
- *    void silc_packet_free(SilcPacketEngine engine, SilcPacket packet);
+ *    void silc_packet_free(SilcPacket packet);
  *
  * DESCRIPTION
  *
  *    This function is used to free the SilcPacket pointer that application
  *    receives in the SilcPacketReceive callback.  Application must free
- *    the packet.
+ *    the packet if it takes it in to processing.
  *
  ***/
-void silc_packet_free(SilcPacketEngine engine, SilcPacket packet);
+void silc_packet_free(SilcPacket packet);
 
 #endif /* SILCPACKET_H */