329 lines
9.3 KiB
C
329 lines
9.3 KiB
C
/******************************************************************************
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* $Id$
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*
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* Copyright (c) 2006-2007 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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#define EXTENDED_HANDSHAKE_ID 0
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#define EXTENDED_PEX_ID 1
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static int
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makeCommonPex( tr_torrent_t * tor, tr_peer_t * peer,
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int ( *peerfunc )( tr_peertree_t *, benc_val_t * ),
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const char * extrakey, benc_val_t * extraval,
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char ** retbuf, int * retlen )
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{
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tr_peertree_t * sent, added, common;
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int ii;
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tr_peer_t * pp;
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tr_peertree_entry_t * found;
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benc_val_t val, * addval, * delval, * extra;
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*retbuf = NULL;
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*retlen = 0;
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sent = &peer->sentPeers;
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peertreeInit( &added );
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peertreeInit( &common );
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/* build trees of peers added and deleted since the last pex */
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for( ii = 0; ii < tor->peerCount; ii++ )
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{
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pp = tor->peers[ii];
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if( 0 == pp->port || 0 == tr_addrcmp( &peer->addr, &pp->addr ) )
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{
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continue;
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}
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found = peertreeGet( sent, &pp->addr, pp->port );
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if( NULL != found )
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{
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peertreeMove( &common, sent, found );
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}
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else if( NULL == peertreeAdd( &added, &pp->addr, pp->port ) )
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{
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peertreeMerge( sent, &common );
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peertreeFree( &added );
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tr_bencFree( extraval );
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return 1;
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}
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}
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/* check if there were any added or deleted peers */
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if( peertreeEmpty( &added ) && peertreeEmpty( sent ) )
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{
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peertreeMerge( sent, &common );
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peertreeFree( &added );
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tr_bencFree( extraval );
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return 0;
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}
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/* build the dictionaries */
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tr_bencInit( &val, TYPE_DICT );
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if( tr_bencDictReserve( &val, 3 ) )
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{
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tr_bencFree( &val );
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peertreeMerge( sent, &common );
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peertreeFree( &added );
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tr_bencFree( extraval );
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return 1;
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}
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extra = tr_bencDictAdd( &val, extrakey );
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addval = tr_bencDictAdd( &val, "added" );
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delval = tr_bencDictAdd( &val, "dropped" );
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assert( NULL != extra && NULL != addval && NULL != delval );
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if( (*peerfunc)( &added, addval ) || (*peerfunc)( sent, delval ) )
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{
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tr_bencFree( &val );
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peertreeMerge( sent, &common );
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peertreeFree( &added );
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tr_bencFree( extraval );
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return 1;
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}
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*extra = *extraval;
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memset( extraval, 0, sizeof( extraval ) );
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/* bencode it */
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*retbuf = tr_bencSaveMalloc( &val, retlen );
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tr_bencFree( &val );
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if( NULL == *retbuf )
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{
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peertreeMerge( sent, &common );
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peertreeFree( &added );
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return 1;
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}
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peertreeSwap( sent, &common );
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peertreeMerge( sent, &added );
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peertreeFree( &common );
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return 0;
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}
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static char *
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makeExtendedHandshake( tr_torrent_t * tor, tr_peer_t * peer, int * len )
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{
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benc_val_t val, * msgsval;
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char * buf, * vers;
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/* get human-readable version string */
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vers = NULL;
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asprintf( &vers, "%s %s", TR_NAME, VERSION_STRING );
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if( NULL == vers )
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{
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return NULL;
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}
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/* reserve space in toplevel dictionary for v, m, and possibly p */
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tr_bencInit( &val, TYPE_DICT );
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if( tr_bencDictReserve( &val, ( 0 < tor->publicPort ? 3 : 2 ) ) )
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{
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free( vers );
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tr_bencFree( &val );
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return NULL;
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}
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/* human readable version string */
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tr_bencInitStr( tr_bencDictAdd( &val, "v" ), vers, 0, 0 );
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/* create dict of supported extended messages */
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msgsval = tr_bencDictAdd( &val, "m" );
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tr_bencInit( msgsval, TYPE_DICT );
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if( tr_bencDictReserve( msgsval, 1 ) )
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{
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tr_bencFree( &val );
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return NULL;
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}
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/* for public torrents advertise utorrent pex message */
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tr_bencInitInt( tr_bencDictAdd( msgsval, "ut_pex" ),
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( peer->private ? 0 : EXTENDED_PEX_ID ) );
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/* our listening port */
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if( 0 < tor->publicPort )
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{
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/* XXX should inform peer when we no longer have a valid port */
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tr_bencInitInt( tr_bencDictAdd( &val, "p" ), tor->publicPort );
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}
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/* bencode it */
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buf = tr_bencSaveMalloc( &val, len );
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tr_bencFree( &val );
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if( NULL == buf )
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{
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return NULL;
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}
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peer->advertisedPort = tor->publicPort;
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return buf;
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}
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static int
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peertreeToBencUT( tr_peertree_t * tree, benc_val_t * val )
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{
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char * buf;
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tr_peertree_entry_t * ii;
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int count;
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count = peertreeCount( tree );
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if( 0 == count )
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{
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tr_bencInitStr( val, NULL, 0, 1 );
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return 0;
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}
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buf = malloc( 6 * count );
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if( NULL == buf )
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{
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return 1;
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}
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tr_bencInitStr( val, buf, 6 * count, 0 );
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for( ii = peertreeFirst( tree ); NULL != ii;
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ii = peertreeNext( tree, ii ) )
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{
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assert( 0 < count );
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count--;
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memcpy( buf + 6 * count, ii->peer, 6 );
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}
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assert( 0 == count );
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return 0;
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}
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static int
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makeUTPex( tr_torrent_t * tor, tr_peer_t * peer, char ** buf, int * len )
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{
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benc_val_t val;
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assert( !peer->private );
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tr_bencInitStr( &val, NULL, 0, 1 );
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return makeCommonPex( tor, peer, peertreeToBencUT, "added.f", &val,
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buf, len );
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}
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static inline int
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parseExtendedHandshake( tr_peer_t * peer, uint8_t * buf, int len )
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{
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benc_val_t val, * sub;
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int dbgport, dbgpex;
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if( tr_bencLoad( buf, len, &val, NULL ) )
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{
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peer_dbg( "GET extended-handshake, invalid bencoding" );
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return TR_ERROR;
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}
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if( TYPE_DICT != val.type )
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{
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peer_dbg( "GET extended-handshake, not a dictionary" );
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tr_bencFree( &val );
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return TR_ERROR;
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}
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/* check supported messages for utorrent pex */
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sub = tr_bencDictFind( &val, "m" );
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dbgpex = -1;
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if( NULL != sub && TYPE_DICT == sub->type )
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{
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sub = tr_bencDictFind( sub, "ut_pex" );
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if( NULL != sub && TYPE_INT == sub->type )
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{
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peer->pexStatus = 0;
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if( 0x0 < sub->val.i && 0xff >= sub->val.i )
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{
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peer->pexStatus = sub->val.i;
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dbgpex = sub->val.i;
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}
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}
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}
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#if 0 /* ugh, we have to deal with encoding if we do this */
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/* get peer's client name */
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sub = tr_bencDictFind( &val, "v" );
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if( NULL != sub && TYPE_STR == sub->type &&
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( NULL == peer->client || 0 != strcmp( sub->val.s.s, peer->client ) ) )
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{
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client = tr_bencStealStr( sub );
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if( NULL != client )
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{
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free( peer->client );
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peer->client = client;
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}
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}
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#endif
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/* get peer's listening port */
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sub = tr_bencDictFind( &val, "p" );
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dbgport = -1;
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if( NULL != sub && TYPE_INT == sub->type &&
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0x0 < sub->val.i && 0xffff >= sub->val.i )
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{
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peer->port = htons( (uint16_t) sub->val.i );
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dbgport = sub->val.i;
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}
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peer_dbg( "GET extended-handshake, ok port=%i pex=%i", dbgport, dbgpex );
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tr_bencFree( &val );
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return TR_OK;
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}
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static inline int
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parseUTPex( tr_torrent_t * tor, tr_peer_t * peer, uint8_t * buf, int len )
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{
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benc_val_t val, * sub;
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int used;
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if( peer->private || PEX_PEER_CUTOFF <= tor->peerCount )
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{
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peer_dbg( "GET extended-pex, ignoring p=%i c=(%i<=%i)",
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peer->private, PEX_PEER_CUTOFF, tor->peerCount );
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return TR_OK;
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}
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if( tr_bencLoad( buf, len, &val, NULL ) )
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{
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peer_dbg( "GET extended-pex, invalid bencoding" );
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return TR_ERROR;
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}
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if( TYPE_DICT != val.type )
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{
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tr_bencFree( &val );
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peer_dbg( "GET extended-pex, not a dictionary" );
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return TR_ERROR;
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}
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sub = tr_bencDictFind( &val, "added" );
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if( NULL != sub && TYPE_STR == sub->type && 0 == sub->val.s.i % 6 )
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{
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used = tr_torrentAddCompact( tor, TR_PEER_FROM_PEX,
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( uint8_t * )sub->val.s.s,
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sub->val.s.i / 6 );
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peer_dbg( "GET extended-pex, got %i peers, used %i",
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sub->val.s.i / 6, used );
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}
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else
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{
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peer_dbg( "GET extended-pex, no peers" );
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}
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tr_bencFree( &val );
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return TR_OK;
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}
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