388 lines
11 KiB
C
388 lines
11 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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static void updateInterest( tr_torrent_t * tor, tr_peer_t * peer );
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/***********************************************************************
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* peerInit
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***********************************************************************
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* Allocates a new tr_peer_t and returns a pointer to it.
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**********************************************************************/
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static tr_peer_t * peerInit()
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{
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tr_peer_t * peer;
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peer = calloc( sizeof( tr_peer_t ), 1 );
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peertreeInit( &peer->sentPeers );
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peer->amChoking = 1;
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peer->peerChoking = 1;
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peer->date = tr_date();
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peer->keepAlive = peer->date;
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peer->download = tr_rcInit();
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peer->upload = tr_rcInit();
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return peer;
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}
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static int peerCmp( tr_peer_t * peer1, tr_peer_t * peer2 )
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{
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/* Wait until we got the peers' ids */
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if( peer1->status <= PEER_STATUS_HANDSHAKE ||
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peer2->status <= PEER_STATUS_HANDSHAKE )
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{
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return 1;
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}
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return memcmp( peer1->id, peer2->id, 20 );
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}
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static int checkPeer( tr_peer_t * peer )
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{
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tr_torrent_t * tor = peer->tor;
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uint64_t now;
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int idleTime, peersWanted, percentOfRange;
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int ret;
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now = tr_date();
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idleTime = now - peer->date;
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/* assume any peer over with an idleTime lower than
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8 seconds has not timed out */
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if ( idleTime > MIN_CON_TIMEOUT )
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{
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peersWanted = ( TR_MAX_PEER_COUNT * PERCENT_PEER_WANTED ) / 100;
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if ( tor->peerCount > peersWanted )
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{
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/* strict requirements for connecting timeout */
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if ( peer->status < PEER_STATUS_CONNECTED )
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{
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peer_dbg( "connection timeout, idled %i seconds",
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( idleTime / 1000 ) );
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return TR_ERROR;
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}
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/* strict requirements for idle uploading timeout */
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if ( peer->inRequestCount && idleTime > MIN_UPLOAD_IDLE )
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{
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peer_dbg( "idle uploader timeout, idled %i seconds",
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( idleTime / 1000 ) );
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return TR_ERROR;
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}
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/* strict requirements for keep-alive timeout */
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if ( idleTime > MIN_KEEP_ALIVE )
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{
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peer_dbg( "peer timeout, idled %i seconds",
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( idleTime / 1000 ) );
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return TR_ERROR;
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}
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}
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/* if we are tight for peers, relax the enforcement of timeouts */
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else
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{
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percentOfRange = tor->peerCount / (TR_MAX_PEER_COUNT - peersWanted);
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/* relax requirements for connecting timeout */
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if ( peer->status < PEER_STATUS_CONNECTED && idleTime > MIN_CON_TIMEOUT +
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( MAX_CON_TIMEOUT - MIN_CON_TIMEOUT ) * percentOfRange )
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{
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peer_dbg( "connection timeout, idled %i seconds",
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( idleTime / 1000 ) );
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return TR_ERROR;
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}
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/* relax requirements for idle uploading timeout */
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if ( peer->inRequestCount && idleTime > MIN_UPLOAD_IDLE +
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( MAX_UPLOAD_IDLE - MIN_UPLOAD_IDLE ) * percentOfRange )
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{
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peer_dbg( "idle uploader timeout, idled %i seconds",
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( idleTime / 1000 ) );
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return TR_ERROR;
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}
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/* relax requirements for keep-alive timeout */
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if ( idleTime > MIN_KEEP_ALIVE +
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( MAX_KEEP_ALIVE - MIN_KEEP_ALIVE ) * percentOfRange )
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{
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peer_dbg( "peer timeout, idled %i seconds",
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( idleTime / 1000 ) );
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return TR_ERROR;
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}
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}
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}
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if( PEER_STATUS_CONNECTED == peer->status )
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{
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/* Send keep-alive every 1 minute and 45 seconds */
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if( now > peer->keepAlive + 105000 )
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{
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sendKeepAlive( peer );
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peer->keepAlive = now;
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}
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/* Resend extended handshake if our public port changed */
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if( EXTENDED_HANDSHAKE == peer->extStatus &&
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tor->publicPort != peer->advertisedPort )
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{
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sendExtended( tor, peer, EXTENDED_HANDSHAKE_ID );
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}
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/* Send peer list */
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if( !peer->private && 0 < peer->pexStatus )
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{
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if( 0 == peer->lastPex )
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{
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/* randomize time when first pex message is sent */
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peer->lastPex = now - 1000 * tr_rand( PEX_INTERVAL );
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}
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if( now > peer->lastPex + 1000 * PEX_INTERVAL )
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{
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if( EXTENDED_HANDSHAKE == peer->extStatus )
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{
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ret = sendExtended( tor, peer, EXTENDED_PEX_ID );
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}
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else if( peer->azproto )
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{
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ret = sendAZPex( tor, peer );
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}
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else
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{
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assert( 0 );
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ret = TR_ERROR;
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}
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if( ret )
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{
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return ret;
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}
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peer->lastPex = now + 1000 *
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( PEX_INTERVAL + tr_rand( PEX_INTERVAL / 10 ) );
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}
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}
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}
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return TR_OK;
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}
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/***********************************************************************
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* isInteresting
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***********************************************************************
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* Returns 1 if 'peer' has at least one piece that we haven't completed,
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* or 0 otherwise.
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**********************************************************************/
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static int isInteresting( tr_torrent_t * tor, tr_peer_t * peer )
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{
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int ii;
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tr_bitfield_t * bitfield = tr_cpPieceBitfield( tor->completion );
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if( !peer->bitfield )
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{
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/* We don't know what this peer has */
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return 0;
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}
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assert( bitfield->len == peer->bitfield->len );
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for( ii = 0; ii < bitfield->len; ii++ )
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{
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if( ( peer->bitfield->bits[ii] & ~(bitfield->bits[ii]) ) & 0xFF )
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{
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return 1;
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}
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}
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return 0;
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}
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static void updateInterest( tr_torrent_t * tor, tr_peer_t * peer )
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{
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int interested = isInteresting( tor, peer );
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if( interested && !peer->amInterested )
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{
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sendInterest( peer, 1 );
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}
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if( !interested && peer->amInterested )
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{
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sendInterest( peer, 0 );
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}
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}
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/***********************************************************************
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* chooseBlock
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***********************************************************************
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* At this point, we know the peer has at least one block we have an
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* interest in. If he has more than one, we choose which one we are
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* going to ask first.
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* Our main goal is to complete pieces, so we look the pieces which are
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* missing less blocks.
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**********************************************************************/
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static inline int chooseBlock( tr_torrent_t * tor, tr_peer_t * peer )
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{
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tr_info_t * inf = &tor->info;
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int i;
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int missingBlocks, minMissing;
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int poolSize, * pool;
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int block, minDownloading;
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/* Choose a piece */
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pool = malloc( inf->pieceCount * sizeof( int ) );
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poolSize = 0;
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minMissing = tor->blockCount + 1;
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for( i = 0; i < inf->pieceCount; i++ )
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{
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missingBlocks = tr_cpMissingBlocksForPiece( tor->completion, i );
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if( missingBlocks < 1 )
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{
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/* We already have or are downloading all blocks */
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continue;
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}
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if( !tr_bitfieldHas( peer->bitfield, i ) )
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{
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/* The peer doesn't have this piece */
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continue;
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}
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if( peer->banfield && tr_bitfieldHas( peer->banfield, i ) )
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{
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/* The peer is banned for this piece */
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continue;
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}
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/* We are interested in this piece, remember it */
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if( missingBlocks < minMissing )
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{
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minMissing = missingBlocks;
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poolSize = 0;
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}
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if( missingBlocks <= minMissing )
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{
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pool[poolSize++] = i;
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}
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}
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if( poolSize )
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{
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/* All pieces in 'pool' have 'minMissing' missing blocks. Find
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the rarest ones. */
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tr_bitfield_t * bitfield;
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int piece;
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int min, foo, j;
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int * pool2;
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int pool2Size;
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pool2 = malloc( poolSize * sizeof( int ) );
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pool2Size = 0;
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min = TR_MAX_PEER_COUNT + 1;
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for( i = 0; i < poolSize; i++ )
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{
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foo = 0;
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for( j = 0; j < tor->peerCount; j++ )
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{
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bitfield = tor->peers[j]->bitfield;
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if( bitfield && tr_bitfieldHas( bitfield, pool[i] ) )
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{
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foo++;
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}
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}
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if( foo < min )
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{
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min = foo;
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pool2Size = 0;
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}
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if( foo <= min )
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{
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pool2[pool2Size++] = pool[i];
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}
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}
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free( pool );
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if( pool2Size < 1 )
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{
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/* Shouldn't happen */
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free( pool2 );
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return -1;
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}
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/* All pieces in pool2 have the same number of missing blocks,
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and are availabme from the same number of peers. Pick a
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random one */
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piece = pool2[tr_rand(pool2Size)];
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free( pool2 );
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/* Pick a block in this piece */
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block = tr_cpMissingBlockInPiece( tor->completion, piece );
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goto check;
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}
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free( pool );
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/* "End game" mode */
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minDownloading = 255;
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block = -1;
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for( i = 0; i < inf->pieceCount; i++ )
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{
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int downloaders, block2;
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if( !tr_bitfieldHas( peer->bitfield, i ) )
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{
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/* The peer doesn't have this piece */
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continue;
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}
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if( peer->banfield && tr_bitfieldHas( peer->banfield, i ) )
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{
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/* The peer is banned for this piece */
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continue;
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}
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if( tr_cpPieceIsComplete( tor->completion, i ) )
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{
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/* We already have it */
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continue;
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}
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block2 = tr_cpMostMissingBlockInPiece( tor->completion, i, &downloaders );
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if( block2 > -1 && downloaders < minDownloading )
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{
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block = block2;
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minDownloading = downloaders;
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}
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}
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check:
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if( block < 0 )
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{
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/* Shouldn't happen */
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return -1;
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}
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for( i = 0; i < peer->inRequestCount; i++ )
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{
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tr_request_t * r;
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r = &peer->inRequests[i];
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if( tr_block( r->index, r->begin ) == block )
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{
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/* We are already asking this peer for this block */
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return -1;
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}
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}
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return block;
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}
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