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transmission/libtransmission/peermessages.h

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/******************************************************************************
* $Id$
*
* Copyright (c) 2005-2007 Transmission authors and contributors
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*****************************************************************************/
/***********************************************************************
* This file handles all outgoing messages
**********************************************************************/
#define PEER_MSG_CHOKE 0
#define PEER_MSG_UNCHOKE 1
#define PEER_MSG_INTERESTED 2
#define PEER_MSG_UNINTERESTED 3
#define PEER_MSG_HAVE 4
#define PEER_MSG_BITFIELD 5
#define PEER_MSG_REQUEST 6
#define PEER_MSG_PIECE 7
#define PEER_MSG_CANCEL 8
#define PEER_MSG_PORT 9
static uint8_t * messagesPending( tr_peer_t * peer, int * size )
{
if( peer->outBlockSending || peer->outMessagesPos < 1 )
{
return NULL;
}
*size = MIN( peer->outMessagesPos, 1024 );
return peer->outMessages;
}
static void messagesSent( tr_peer_t * peer, int size )
{
peer->outMessagesPos -= size;
memmove( peer->outMessages, &peer->outMessages[size],
peer->outMessagesPos );
}
static int
getHeaderSize( tr_peer_t * peer, int id )
{
int size, index;
size = 4;
if( peer->azproto )
{
index = azmsgIdIndex( id );
assert( 0 <= index );
size += 4 + azmsgLen( index ) + 1;
}
else if( 0 <= id )
{
size++;
}
return size;
}
static uint8_t *
fillHeader( tr_peer_t * peer, int size, int id, uint8_t * buf )
{
int index;
tr_htonl( size - 4, buf );
buf += 4;
if( peer->azproto )
{
index = azmsgIdIndex( id );
assert( 0 <= index );
tr_htonl( azmsgLen( index ), buf );
buf += 4;
memcpy( buf, azmsgStr( index ), azmsgLen( index ) );
buf += azmsgLen( index );
buf[0] = AZ_EXT_VERSION;
buf++;
}
else if( 0 <= id )
{
assert( 0 <= id && 0xff > id );
*buf = id;
buf++;
}
return buf;
}
static uint8_t *
blockPending( tr_torrent * tor,
tr_peer_t * peer,
int * size )
{
if( !peer->outBlockLoaded ) /* we need to load the block for the next request */
{
uint8_t * buf;
tr_request_t * r;
int hdrlen;
if( peer->isChokedByUs ) /* we don't want to send them anything */
return NULL;
if( !peer->outRequests ) /* nothing to send */
return NULL;
r = (tr_request_t*) peer->outRequests->data;
assert( r != NULL );
tr_list_remove_data( &peer->outRequests, r );
if( !tr_cpPieceIsComplete( tor->completion, r->index ) ) /* sanity clause */
{
/* We've been asked for something we don't have. buggy client? */
tr_inf( "Block %d/%d/%d was requested but we don't have it",
r->index, r->begin, r->length );
tr_free( r );
return NULL;
}
hdrlen = 4 + 4 + r->length + getHeaderSize( peer, PEER_MSG_PIECE );
assert( hdrlen <= ( signed )sizeof peer->outBlock );
buf = fillHeader( peer, hdrlen, PEER_MSG_PIECE, peer->outBlock );
tr_htonl( r->index, buf );
buf += 4;
tr_htonl( r->begin, buf );
buf += 4;
tr_ioRead( tor, r->index, r->begin, r->length, buf );
peer_dbg( "SEND piece %d/%d (%d bytes)",
r->index, r->begin, r->length );
peer->outBlockSize = hdrlen;
peer->outBlockLoaded = 1;
tr_free( r );
}
*size = MIN( 1024, peer->outBlockSize );
return (uint8_t *) peer->outBlock;
}
static void blockSent( tr_peer_t * peer, int size )
{
peer->outBlockSize -= size;
memmove( peer->outBlock, &peer->outBlock[size], peer->outBlockSize );
if( peer->outBlockSize > 0 )
{
/* We can't send messages until we are done sending the block */
peer->outBlockSending = 1;
}
else
{
/* Block fully sent */
peer->outBlockSending = 0;
peer->outBlockLoaded = 0;
}
}
static uint8_t * getMessagePointer( tr_peer_t * peer, int size, int id )
{
uint8_t * buf;
size += getHeaderSize( peer, id );
if( peer->outMessagesPos + size > peer->outMessagesSize )
{
peer->outMessagesSize = peer->outMessagesPos + size;
peer->outMessages = realloc( peer->outMessages,
peer->outMessagesSize );
}
buf = &peer->outMessages[peer->outMessagesPos];
peer->outMessagesPos += size;
return fillHeader( peer, size, id, buf );
}
/***********************************************************************
* sendKeepAlive
***********************************************************************
*
**********************************************************************/
static void sendKeepAlive( tr_peer_t * peer )
{
getMessagePointer( peer, 0, AZ_MSG_BT_KEEP_ALIVE );
peer_dbg( "SEND keep-alive" );
}
/***********************************************************************
* sendChoke
***********************************************************************
*
**********************************************************************/
static void sendChoke( tr_peer_t * peer, int yes )
{
int id;
id = ( yes ? PEER_MSG_CHOKE : PEER_MSG_UNCHOKE );
getMessagePointer( peer, 0, id );
peer->isChokedByUs = yes;
if( !yes )
{
/* Drop older requests from the last time it was unchoked, if any */
tr_list_foreach( peer->outRequests, tr_free );
tr_list_free( &peer->outRequests );
peer->outRequests = NULL;
}
peer_dbg( "SEND %schoke", yes ? "" : "un" );
}
/***********************************************************************
* sendInterest
***********************************************************************
*
**********************************************************************/
static void sendInterest( tr_peer_t * peer, int yes )
{
int id;
id = ( yes ? PEER_MSG_INTERESTED : PEER_MSG_UNINTERESTED );
getMessagePointer( peer, 0, id );
peer->isInteresting = yes;
peer_dbg( "SEND %sinterested", yes ? "" : "un" );
}
/***********************************************************************
* sendHave
***********************************************************************
*
**********************************************************************/
static void sendHave( tr_peer_t * peer, int piece )
{
uint8_t * p;
p = getMessagePointer( peer, 4, PEER_MSG_HAVE );
tr_htonl( piece, p );
peer_dbg( "SEND have %d", piece );
}
/***********************************************************************
* sendBitfield
***********************************************************************
* Builds a 'bitfield' message:
* - size = 5 + X (4 bytes)
* - id = 5 (1 byte)
* - bitfield (X bytes)
**********************************************************************/
static void sendBitfield( tr_torrent * tor, tr_peer_t * peer )
{
uint8_t * p;
const tr_bitfield * bitfield;
bitfield = tr_cpPieceBitfield( tor->completion );
p = getMessagePointer( peer, bitfield->len, PEER_MSG_BITFIELD );
memcpy( p, bitfield->bits, bitfield->len );
peer_dbg( "SEND bitfield" );
}
/***********************************************************************
* sendRequest
***********************************************************************
*
**********************************************************************/
static void sendRequest( tr_torrent * tor, tr_peer_t * peer, int block )
{
tr_info * inf = &tor->info;
tr_request_t * r;
uint8_t * p;
/* Get the piece the block is a part of, its position in the piece
and its size */
r = &peer->inRequests[peer->inRequestCount];
r->index = block / ( inf->pieceSize / tor->blockSize );
r->begin = ( block % ( inf->pieceSize / tor->blockSize ) ) *
tor->blockSize;
r->length = tr_torBlockCountBytes( tor, block );
(peer->inRequestCount)++;
/* Build the "ask" message */
p = getMessagePointer( peer, 12, PEER_MSG_REQUEST );
tr_htonl( r->index, p );
tr_htonl( r->begin, p + 4 );
tr_htonl( r->length, p + 8 );
tr_cpDownloaderAdd( tor->completion, block );
peer_dbg( "SEND request %d/%d (%d bytes)",
r->index, r->begin, r->length );
}
/***********************************************************************
* sendCancel
***********************************************************************
*
**********************************************************************/
static void sendCancel( tr_peer_t * peer, int index, int begin,
int length )
{
uint8_t * p;
p = getMessagePointer( peer, 12, PEER_MSG_CANCEL );
tr_htonl( index, p );
tr_htonl( begin, p + 4 );
tr_htonl( length, p + 8 );
peer_dbg( "SEND cancel %d/%d (%d bytes)", index, begin, length );
}
/***********************************************************************
* broadcastCancel
***********************************************************************
*
**********************************************************************/
static void broadcastCancel( tr_torrent * tor, int index, int begin,
int length )
{
int i, j;
tr_peer_t * peer;
tr_request_t * r;
for( i = 0; i < tor->peerCount; i++ )
{
peer = tor->peers[i];
for( j = 0; j < peer->inRequestCount; j++ )
{
r = &peer->inRequests[j];
if( r->index != index || r->begin != begin ||
r->length != length )
{
continue;
}
sendCancel( peer, index, begin, length );
(peer->inRequestCount)--;
memmove( &peer->inRequests[j], &peer->inRequests[j+1],
( peer->inRequestCount - j ) * sizeof( tr_request_t ) );
break;
}
}
}
/***********************************************************************
* sendExtended
***********************************************************************
* Builds an extended message:
* - size = 6 + X (4 bytes)
* - id = 20 (1 byte)
* - eid = Y (1 byte)
* - data (X bytes)
**********************************************************************/
static int sendExtended( tr_torrent * tor, tr_peer_t * peer, int id )
{
uint8_t * p;
char * buf;
int len;
buf = NULL;
switch( id )
{
case EXTENDED_HANDSHAKE_ID:
buf = makeExtendedHandshake( tor, peer, &len );
if( NULL == buf )
{
return TR_ERROR;
}
peer_dbg( "SEND extended-handshake, %s pex",
( peer->private ? "without" : "with" ) );
break;
case EXTENDED_PEX_ID:
if( makeUTPex( tor, peer, &buf, &len ) )
{
return TR_ERROR;
}
else if( NULL == buf )
{
return TR_OK;
}
peer_dbg( "SEND extended-pex" );
break;
default:
assert( 0 );
break;
}
/* add header and queue it to be sent */
p = getMessagePointer( peer, 1 + len, PEER_MSG_EXTENDED );
p[0] = id;
memcpy( p + 1, buf, len );
free( buf );
return TR_OK;
}
/***********************************************************************
* sendAZPex
***********************************************************************
*
**********************************************************************/
static int sendAZPex( tr_torrent * tor, tr_peer_t * peer )
{
uint8_t * p;
char * buf;
int len;
if( makeAZPex( tor, peer, &buf, &len ) )
{
return TR_ERROR;
}
else if( NULL == buf )
{
return TR_OK;
}
/* add header and queue it to be sent */
p = getMessagePointer( peer, len, AZ_MSG_AZ_PEER_EXCHANGE );
memcpy( p, buf, len );
free( buf );
peer_dbg( "SEND azureus-pex" );
return TR_OK;
}
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