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