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transmission/libtransmission/peer-mgr.c

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/*
* This file Copyright (C) 2007-2008 Charles Kerr <charles@rebelbase.com>
*
* This file is licensed by the GPL version 2. Works owned by the
* Transmission project are granted a special exemption to clause 2(b)
* so that the bulk of its code can remain under the MIT license.
* This exemption does not extend to derived works not owned by
* the Transmission project.
*
* $Id$
*/
#include <assert.h>
#include <string.h> /* memcpy, memcmp, strstr */
#include <stdlib.h> /* qsort */
#include <stdio.h> /* printf */
#include <limits.h> /* INT_MAX */
#include <libgen.h> /* basename */
#include <event.h>
#include "transmission.h"
#include "clients.h"
#include "completion.h"
#include "crypto.h"
#include "handshake.h"
#include "net.h"
#include "peer-io.h"
#include "peer-mgr.h"
#include "peer-mgr-private.h"
#include "peer-msgs.h"
#include "platform.h"
#include "ptrarray.h"
#include "ratecontrol.h"
#include "shared.h"
#include "torrent.h"
#include "trcompat.h" /* strlcpy */
#include "trevent.h"
#include "utils.h"
/**
*** The "SWIFT" system is described by Karthik Tamilmani,
*** Vinay Pai, and Alexander Mohr of Stony Brook University
*** in their paper "SWIFT: A System With Incentives For Trading"
*** http://citeseer.ist.psu.edu/tamilmani04swift.html
***
*** More SWIFT constants are defined in peer-mgr-private.h
**/
/**
* Allow new peers to download this many bytes from
* us when getting started. This can prevent gridlock
* with other peers using tit-for-tat algorithms
*/
static const int SWIFT_INITIAL_CREDIT = 64 * 1024; /* 64 KiB */
/**
* We expend a fraction of our torrent's total upload speed
* on largesse by uniformly distributing free credit to
* all of our peers. This too helps prevent gridlock.
*/
static const double SWIFT_LARGESSE = 0.15; /* 15% of our UL */
/**
* How frequently to extend largesse-based credit
*/
static const int SWIFT_PERIOD_MSEC = 5000;
enum
{
/* how frequently to change which peers are choked */
RECHOKE_PERIOD_MSEC = (10 * 1000),
/* how frequently to refill peers' request lists */
REFILL_PERIOD_MSEC = 666,
/* following the BT spec, we consider ourselves `snubbed' if
* we're we don't get piece data from a peer in this long */
SNUBBED_SEC = 60,
/* when many peers are available, keep idle ones this long */
MIN_UPLOAD_IDLE_SECS = (60 * 3),
/* when few peers are available, keep idle ones this long */
MAX_UPLOAD_IDLE_SECS = (60 * 10),
/* how frequently to decide which peers live and die */
RECONNECT_PERIOD_MSEC = (3 * 1000),
/* max # of peers to ask fer per torrent per reconnect pulse */
MAX_RECONNECTIONS_PER_PULSE = 4,
/* max number of peers to ask for per second overall.
* this throttle is to avoid overloading the router */
MAX_CONNECTIONS_PER_SECOND = 16,
/* corresponds to ut_pex's added.f flags */
ADDED_F_ENCRYPTION_FLAG = 1,
/* corresponds to ut_pex's added.f flags */
ADDED_F_SEED_FLAG = 2,
/* number of bad pieces a peer is allowed to send before we ban them */
MAX_BAD_PIECES_PER_PEER = 3,
/* use for bitwise operations w/peer_atom.myflags */
MYFLAG_BANNED = 1,
/* unreachable for now... but not banned. if they try to connect to us it's okay */
MYFLAG_UNREACHABLE = 2
};
/**
***
**/
/* We keep one of these for every peer we know about, whether
* it's connected or not, so the struct must be small.
* When our current connections underperform, we dip back
* into this list for new ones. */
struct peer_atom
{
uint8_t from;
uint8_t flags; /* these match the added_f flags */
uint8_t myflags; /* flags that aren't defined in added_f */
uint16_t port;
uint16_t numFails;
struct in_addr addr;
time_t time;
time_t piece_data_time;
};
typedef struct
{
uint8_t hash[SHA_DIGEST_LENGTH];
tr_ptrArray * outgoingHandshakes; /* tr_handshake */
tr_ptrArray * pool; /* struct peer_atom */
tr_ptrArray * peers; /* tr_peer */
tr_timer * reconnectTimer;
tr_timer * rechokeTimer;
tr_timer * refillTimer;
tr_timer * swiftTimer;
tr_torrent * tor;
tr_peer * optimistic; /* the optimistic peer, or NULL if none */
tr_bitfield * requested;
unsigned int isRunning : 1;
struct tr_peerMgr * manager;
}
Torrent;
struct tr_peerMgr
{
tr_handle * handle;
tr_ptrArray * torrents; /* Torrent */
tr_ptrArray * incomingHandshakes; /* tr_handshake */
};
/**
***
**/
static void
myDebug( const char * file, int line, const Torrent * t, const char * fmt, ... )
{
FILE * fp = tr_getLog( );
if( fp != NULL )
{
va_list args;
char timestr[64];
struct evbuffer * buf = evbuffer_new( );
char * myfile = tr_strdup( file );
evbuffer_add_printf( buf, "[%s] ", tr_getLogTimeStr( timestr, sizeof(timestr) ) );
if( t != NULL )
evbuffer_add_printf( buf, "%s ", t->tor->info.name );
va_start( args, fmt );
evbuffer_add_vprintf( buf, fmt, args );
va_end( args );
evbuffer_add_printf( buf, " (%s:%d)\n", basename(myfile), line );
fwrite( EVBUFFER_DATA(buf), 1, EVBUFFER_LENGTH(buf), fp );
tr_free( myfile );
evbuffer_free( buf );
}
}
#define tordbg(t, fmt...) myDebug(__FILE__, __LINE__, t, ##fmt )
/**
***
**/
static void
managerLock( struct tr_peerMgr * manager )
{
tr_globalLock( manager->handle );
}
static void
managerUnlock( struct tr_peerMgr * manager )
{
tr_globalUnlock( manager->handle );
}
static void
torrentLock( Torrent * torrent )
{
managerLock( torrent->manager );
}
static void
torrentUnlock( Torrent * torrent )
{
managerUnlock( torrent->manager );
}
static int
torrentIsLocked( const Torrent * t )
{
return tr_globalIsLocked( t->manager->handle );
}
/**
***
**/
static int
compareAddresses( const struct in_addr * a, const struct in_addr * b )
{
return tr_compareUint32( a->s_addr, b->s_addr );
}
static int
handshakeCompareToAddr( const void * va, const void * vb )
{
const tr_handshake * a = va;
return compareAddresses( tr_handshakeGetAddr( a, NULL ), vb );
}
static int
handshakeCompare( const void * a, const void * b )
{
return handshakeCompareToAddr( a, tr_handshakeGetAddr( b, NULL ) );
}
static tr_handshake*
getExistingHandshake( tr_ptrArray * handshakes, const struct in_addr * in_addr )
{
return tr_ptrArrayFindSorted( handshakes,
in_addr,
handshakeCompareToAddr );
}
static int
comparePeerAtomToAddress( const void * va, const void * vb )
{
const struct peer_atom * a = va;
return compareAddresses( &a->addr, vb );
}
static int
comparePeerAtoms( const void * va, const void * vb )
{
const struct peer_atom * b = vb;
return comparePeerAtomToAddress( va, &b->addr );
}
/**
***
**/
static int
torrentCompare( const void * va, const void * vb )
{
const Torrent * a = va;
const Torrent * b = vb;
return memcmp( a->hash, b->hash, SHA_DIGEST_LENGTH );
}
static int
torrentCompareToHash( const void * va, const void * vb )
{
const Torrent * a = va;
const uint8_t * b_hash = vb;
return memcmp( a->hash, b_hash, SHA_DIGEST_LENGTH );
}
static Torrent*
getExistingTorrent( tr_peerMgr * manager, const uint8_t * hash )
{
return (Torrent*) tr_ptrArrayFindSorted( manager->torrents,
hash,
torrentCompareToHash );
}
static int
peerCompare( const void * va, const void * vb )
{
const tr_peer * a = va;
const tr_peer * b = vb;
return compareAddresses( &a->in_addr, &b->in_addr );
}
static int
peerCompareToAddr( const void * va, const void * vb )
{
const tr_peer * a = va;
return compareAddresses( &a->in_addr, vb );
}
static tr_peer*
getExistingPeer( Torrent * torrent, const struct in_addr * in_addr )
{
assert( torrentIsLocked( torrent ) );
assert( in_addr != NULL );
return (tr_peer*) tr_ptrArrayFindSorted( torrent->peers,
in_addr,
peerCompareToAddr );
}
static struct peer_atom*
getExistingAtom( const Torrent * t, const struct in_addr * addr )
{
assert( torrentIsLocked( t ) );
return tr_ptrArrayFindSorted( t->pool, addr, comparePeerAtomToAddress );
}
static int
peerIsInUse( const Torrent * ct, const struct in_addr * addr )
{
Torrent * t = (Torrent*) ct;
assert( torrentIsLocked ( t ) );
return getExistingPeer( t, addr )
|| getExistingHandshake( t->outgoingHandshakes, addr )
|| getExistingHandshake( t->manager->incomingHandshakes, addr );
}
static tr_peer*
peerConstructor( const struct in_addr * in_addr )
{
tr_peer * p;
p = tr_new0( tr_peer, 1 );
p->credit = SWIFT_INITIAL_CREDIT;
p->rcToClient = tr_rcInit( );
p->rcToPeer = tr_rcInit( );
memcpy( &p->in_addr, in_addr, sizeof(struct in_addr) );
return p;
}
static tr_peer*
getPeer( Torrent * torrent, const struct in_addr * in_addr )
{
tr_peer * peer;
assert( torrentIsLocked( torrent ) );
peer = getExistingPeer( torrent, in_addr );
if( peer == NULL ) {
peer = peerConstructor( in_addr );
tr_ptrArrayInsertSorted( torrent->peers, peer, peerCompare );
}
return peer;
}
static void
peerDestructor( tr_peer * peer )
{
assert( peer != NULL );
assert( peer->msgs != NULL );
tr_peerMsgsUnsubscribe( peer->msgs, peer->msgsTag );
tr_peerMsgsFree( peer->msgs );
tr_peerIoFree( peer->io );
tr_bitfieldFree( peer->have );
tr_bitfieldFree( peer->blame );
tr_rcClose( peer->rcToClient );
tr_rcClose( peer->rcToPeer );
tr_free( peer->client );
tr_free( peer );
}
static void
removePeer( Torrent * t, tr_peer * peer )
{
tr_peer * removed;
struct peer_atom * atom;
assert( torrentIsLocked( t ) );
atom = getExistingAtom( t, &peer->in_addr );
assert( atom != NULL );
atom->time = time( NULL );
removed = tr_ptrArrayRemoveSorted ( t->peers, peer, peerCompare );
assert( removed == peer );
peerDestructor( removed );
}
static void
removeAllPeers( Torrent * t )
{
while( !tr_ptrArrayEmpty( t->peers ) )
removePeer( t, tr_ptrArrayNth( t->peers, 0 ) );
}
static void
torrentDestructor( Torrent * t )
{
uint8_t hash[SHA_DIGEST_LENGTH];
assert( t != NULL );
assert( !t->isRunning );
assert( t->peers != NULL );
assert( torrentIsLocked( t ) );
assert( tr_ptrArrayEmpty( t->outgoingHandshakes ) );
assert( tr_ptrArrayEmpty( t->peers ) );
memcpy( hash, t->hash, SHA_DIGEST_LENGTH );
tr_timerFree( &t->reconnectTimer );
tr_timerFree( &t->rechokeTimer );
tr_timerFree( &t->refillTimer );
tr_timerFree( &t->swiftTimer );
tr_bitfieldFree( t->requested );
tr_ptrArrayFree( t->pool, (PtrArrayForeachFunc)tr_free );
tr_ptrArrayFree( t->outgoingHandshakes, NULL );
tr_ptrArrayFree( t->peers, NULL );
tr_free( t );
}
static Torrent*
torrentConstructor( tr_peerMgr * manager, tr_torrent * tor )
{
Torrent * t;
t = tr_new0( Torrent, 1 );
t->manager = manager;
t->tor = tor;
t->pool = tr_ptrArrayNew( );
t->peers = tr_ptrArrayNew( );
t->outgoingHandshakes = tr_ptrArrayNew( );
t->requested = tr_bitfieldNew( tor->blockCount );
memcpy( t->hash, tor->info.hash, SHA_DIGEST_LENGTH );
return t;
}
/**
* For explanation, see http://www.bittorrent.org/fast_extensions.html
* Also see the "test-allowed-set" unit test
*/
struct tr_bitfield *
tr_peerMgrGenerateAllowedSet( const uint32_t k, /* number of pieces in set */
const uint32_t sz, /* number of pieces in torrent */
const uint8_t * infohash, /* torrent's SHA1 hash*/
const struct in_addr * ip ) /* peer's address */
{
uint8_t w[SHA_DIGEST_LENGTH + 4];
uint8_t x[SHA_DIGEST_LENGTH];
tr_bitfield_t * a;
uint32_t a_size;
*(uint32_t*)w = ntohl( htonl(ip->s_addr) & 0xffffff00 ); /* (1) */
memcpy( w + 4, infohash, SHA_DIGEST_LENGTH ); /* (2) */
tr_sha1( x, w, sizeof( w ), NULL ); /* (3) */
a = tr_bitfieldNew( sz );
a_size = 0;
while( a_size < k )
{
int i;
for ( i=0; i<5 && a_size<k; ++i ) /* (4) */
{
uint32_t j = i * 4; /* (5) */
uint32_t y = ntohl(*(uint32_t*)(x+j)); /* (6) */
uint32_t index = y % sz; /* (7) */
if ( !tr_bitfieldHas( a, index ) ) { /* (8) */
tr_bitfieldAdd( a, index ); /* (9) */
++a_size;
}
}
tr_sha1( x, x, sizeof( x ), NULL ); /* (3) */
}
return a;
}
tr_peerMgr*
tr_peerMgrNew( tr_handle * handle )
{
tr_peerMgr * m = tr_new0( tr_peerMgr, 1 );
m->handle = handle;
m->torrents = tr_ptrArrayNew( );
m->incomingHandshakes = tr_ptrArrayNew( );
return m;
}
void
tr_peerMgrFree( tr_peerMgr * manager )
{
managerLock( manager );
/* free the handshakes. Abort invokes handshakeDoneCB(), which removes
* the item from manager->handshakes, so this is a little roundabout... */
while( !tr_ptrArrayEmpty( manager->incomingHandshakes ) )
tr_handshakeAbort( tr_ptrArrayNth( manager->incomingHandshakes, 0 ) );
tr_ptrArrayFree( manager->incomingHandshakes, NULL );
/* free the torrents. */
tr_ptrArrayFree( manager->torrents, (PtrArrayForeachFunc)torrentDestructor );
managerUnlock( manager );
tr_free( manager );
}
static tr_peer**
getConnectedPeers( Torrent * t, int * setmeCount )
{
int i, peerCount, connectionCount;
tr_peer **peers;
tr_peer **ret;
assert( torrentIsLocked( t ) );
peers = (tr_peer **) tr_ptrArrayPeek( t->peers, &peerCount );
ret = tr_new( tr_peer*, peerCount );
for( i=connectionCount=0; i<peerCount; ++i )
if( peers[i]->msgs != NULL )
ret[connectionCount++] = peers[i];
*setmeCount = connectionCount;
return ret;
}
/***
**** Refill
***/
struct tr_refill_piece
{
tr_priority_t priority;
int percentDone;
uint16_t random;
uint32_t piece;
uint32_t peerCount;
uint32_t fastAllowed;
uint32_t suggested;
};
static int
compareRefillPiece (const void * aIn, const void * bIn)
{
const struct tr_refill_piece * a = aIn;
const struct tr_refill_piece * b = bIn;
/* if one piece has a higher priority, it goes first */
if( a->priority != b->priority )
return a->priority > b->priority ? -1 : 1;
/* try to fill partial pieces */
if( a->percentDone != b->percentDone )
return a->percentDone > b->percentDone ? -1 : 1;
/* if one *might be* fastallowed to us, get it first...
* I'm putting it on top so we prioritize those pieces at
* startup, then we'll have them, and we'll be denied access
* to them */
if (a->fastAllowed != b->fastAllowed)
return a->fastAllowed < b->fastAllowed ? -1 : 1;
/* otherwise if one was suggested to us, get it */
if (a->suggested != b->suggested)
return a->suggested < b->suggested ? -1 : 1;
/* otherwise if one has fewer peers, it goes first */
if (a->peerCount != b->peerCount)
return a->peerCount < b->peerCount ? -1 : 1;
/* otherwise go with our random seed */
return tr_compareUint16( a->random, b->random );
}
static int
isPieceInteresting( const tr_torrent * tor,
int piece )
{
if( tor->info.pieces[piece].dnd ) /* we don't want it */
return 0;
if( tr_cpPieceIsComplete( tor->completion, piece ) ) /* we have it */
return 0;
return 1;
}
static uint32_t*
getPreferredPieces( Torrent * t,
uint32_t * pieceCount )
{
const tr_torrent * tor = t->tor;
const tr_info * inf = &tor->info;
int i;
uint32_t poolSize = 0;
uint32_t * pool = tr_new( uint32_t, inf->pieceCount );
int peerCount;
tr_peer** peers;
assert( torrentIsLocked( t ) );
peers = getConnectedPeers( t, &peerCount );
for( i=0; i<inf->pieceCount; ++i )
if( isPieceInteresting( tor, i ) )
pool[poolSize++] = i;
/* sort the pool from most interesting to least... */
if( poolSize > 1 )
{
uint32_t j;
struct tr_refill_piece * p = tr_new( struct tr_refill_piece, poolSize );
for( j=0; j<poolSize; ++j )
{
int k;
const int piece = pool[j];
struct tr_refill_piece * setme = p + j;
setme->piece = piece;
setme->priority = inf->pieces[piece].priority;
setme->peerCount = 0;
setme->fastAllowed = 0;
setme->random = tr_rand( UINT16_MAX );
setme->percentDone = (int)( 100.0 * tr_cpPercentBlocksInPiece( tor->completion, piece ) );
for( k=0; k<peerCount; ++k ) {
const tr_peer * peer = peers[k];
if( peer->peerIsInterested && !peer->clientIsChoked && tr_bitfieldHas( peer->have, piece ) )
++setme->peerCount;
/* The fast peer extension doesn't force a peer to actually HAVE a fast-allowed piece,
but we're guaranteed to get the same pieces from different peers,
so we'll build a list and pray one actually have this one */
setme->fastAllowed = tr_peerMsgsIsPieceFastAllowed( peer->msgs, i );
/* Also, if someone SUGGESTed a piece to us, prioritize it over non-suggested others
*/
setme->suggested = tr_peerMsgsIsPieceSuggested( peer->msgs, i );
}
}
qsort( p, poolSize, sizeof(struct tr_refill_piece), compareRefillPiece );
for( j=0; j<poolSize; ++j )
pool[j] = p[j].piece;
tr_free( p );
}
tr_free( peers );
*pieceCount = poolSize;
return pool;
}
static uint64_t*
getPreferredBlocks( Torrent * t, uint64_t * setmeCount )
{
int s;
uint32_t i;
uint32_t pieceCount;
uint32_t blockCount;
uint32_t unreqCount[3], reqCount[3];
uint32_t * pieces;
uint64_t * ret, * walk;
uint64_t * unreq[3], *req[3];
const tr_torrent * tor = t->tor;
assert( torrentIsLocked( t ) );
pieces = getPreferredPieces( t, &pieceCount );
/**
* Now we walk through those preferred pieces to find all the blocks
* are still missing from them. We put unrequested blocks first,
* of course, but by including requested blocks afterwards, endgame
* handling happens naturally.
*
* By doing this once per priority we also effectively get an endgame
* mode for each priority level. The helps keep high priority files
* from getting stuck at 99% due of unresponsive peers.
*/
/* make temporary bins for the four tiers of blocks */
for( i=0; i<3; ++i ) {
req[i] = tr_new( uint64_t, pieceCount * tor->blockCountInPiece );
reqCount[i] = 0;
unreq[i] = tr_new( uint64_t, pieceCount * tor->blockCountInPiece );
unreqCount[i] = 0;
}
/* sort the blocks into our temp bins */
for( i=blockCount=0; i<pieceCount; ++i )
{
const uint32_t index = pieces[i];
const int priorityIndex = tor->info.pieces[index].priority + 1;
const int begin = tr_torPieceFirstBlock( tor, index );
const int end = begin + tr_torPieceCountBlocks( tor, (int)index );
int block;
for( block=begin; block<end; ++block )
{
if( tr_cpBlockIsComplete( tor->completion, block ) )
continue;
++blockCount;
if( tr_bitfieldHas( t->requested, block ) )
{
const uint32_t n = reqCount[priorityIndex]++;
req[priorityIndex][n] = block;
}
else
{
const uint32_t n = unreqCount[priorityIndex]++;
unreq[priorityIndex][n] = block;
}
}
}
/* join the bins together, going from highest priority to lowest so
* the the blocks we want to request first will be first in the list */
ret = walk = tr_new( uint64_t, blockCount );
for( s=2; s>=0; --s ) {
memcpy( walk, unreq[s], sizeof(uint64_t) * unreqCount[s] );
walk += unreqCount[s];
memcpy( walk, req[s], sizeof(uint64_t) * reqCount[s] );
walk += reqCount[s];
}
assert( ( walk - ret ) == ( int )blockCount );
*setmeCount = blockCount;
/* cleanup */
tr_free( pieces );
for( i=0; i<3; ++i ) {
tr_free( unreq[i] );
tr_free( req[i] );
}
return ret;
}
static int
refillPulse( void * vtorrent )
{
Torrent * t = vtorrent;
tr_torrent * tor = t->tor;
uint32_t i;
int peerCount;
tr_peer ** peers;
uint64_t blockCount;
uint64_t * blocks;
if( !t->isRunning )
return TRUE;
if( tr_torrentIsSeed( t->tor ) )
return TRUE;
torrentLock( t );
tordbg( t, "Refilling Request Buffers..." );
blocks = getPreferredBlocks( t, &blockCount );
peers = getConnectedPeers( t, &peerCount );
for( i=0; peerCount && i<blockCount; ++i )
{
const uint64_t block = blocks[i];
const uint32_t index = tr_torBlockPiece( tor, block );
const uint32_t begin = (block * tor->blockSize) - (index * tor->info.pieceSize);
const uint32_t length = tr_torBlockCountBytes( tor, (int)block );
int j;
assert( _tr_block( tor, index, begin ) == (int)block );
assert( begin < (uint32_t)tr_torPieceCountBytes( tor, (int)index ) );
assert( (begin + length) <= (uint32_t)tr_torPieceCountBytes( tor, (int)index ) );
/* find a peer who can ask for this block */
for( j=0; j<peerCount; )
{
const int val = tr_peerMsgsAddRequest( peers[j]->msgs, index, begin, length );
switch( val )
{
case TR_ADDREQ_FULL:
case TR_ADDREQ_CLIENT_CHOKED:
memmove( peers+j, peers+j+1, sizeof(tr_peer*)*(--peerCount-j) );
break;
case TR_ADDREQ_MISSING:
case TR_ADDREQ_DUPLICATE:
++j;
break;
case TR_ADDREQ_OK:
tr_bitfieldAdd( t->requested, block );
j = peerCount;
break;
default:
assert( 0 && "unhandled value" );
break;
}
}
}
/* cleanup */
tr_free( peers );
tr_free( blocks );
t->refillTimer = NULL;
torrentUnlock( t );
return FALSE;
}
static void
broadcastClientHave( Torrent * t, uint32_t index )
{
int i, size;
tr_peer ** peers;
assert( torrentIsLocked( t ) );
peers = getConnectedPeers( t, &size );
for( i=0; i<size; ++i )
tr_peerMsgsHave( peers[i]->msgs, index );
tr_free( peers );
}
static void
broadcastGotBlock( Torrent * t, uint32_t index, uint32_t offset, uint32_t length )
{
int i, size;
tr_peer ** peers;
assert( torrentIsLocked( t ) );
peers = getConnectedPeers( t, &size );
for( i=0; i<size; ++i )
tr_peerMsgsCancel( peers[i]->msgs, index, offset, length );
tr_free( peers );
}
static void
addStrike( Torrent * t, tr_peer * peer )
{
tordbg( t, "increasing peer %s strike count to %d", tr_peerIoAddrStr(&peer->in_addr,peer->port), peer->strikes+1 );
if( ++peer->strikes >= MAX_BAD_PIECES_PER_PEER )
{
struct peer_atom * atom = getExistingAtom( t, &peer->in_addr );
atom->myflags |= MYFLAG_BANNED;
peer->doPurge = 1;
tordbg( t, "banning peer %s", tr_peerIoAddrStr(&atom->addr,atom->port) );
}
}
static void
msgsCallbackFunc( void * vpeer, void * vevent, void * vt )
{
tr_peer * peer = vpeer;
Torrent * t = (Torrent *) vt;
const tr_peermsgs_event * e = (const tr_peermsgs_event *) vevent;
torrentLock( t );
switch( e->eventType )
{
case TR_PEERMSG_NEED_REQ:
if( t->refillTimer == NULL )
t->refillTimer = tr_timerNew( t->manager->handle,
refillPulse, t,
REFILL_PERIOD_MSEC );
break;
case TR_PEERMSG_CANCEL:
tr_bitfieldRem( t->requested, _tr_block( t->tor, e->pieceIndex, e->offset ) );
break;
case TR_PEERMSG_PIECE_DATA: {
struct peer_atom * atom = getExistingAtom( t, &peer->in_addr );
atom->piece_data_time = time( NULL );
break;
}
case TR_PEERMSG_CLIENT_HAVE:
broadcastClientHave( t, e->pieceIndex );
tr_torrentRecheckCompleteness( t->tor );
break;
case TR_PEERMSG_PEER_PROGRESS: {
struct peer_atom * atom = getExistingAtom( t, &peer->in_addr );
const int peerIsSeed = e->progress >= 1.0;
if( peerIsSeed ) {
tordbg( t, "marking peer %s as a seed", tr_peerIoAddrStr(&atom->addr,atom->port) );
atom->flags |= ADDED_F_SEED_FLAG;
} else {
tordbg( t, "marking peer %s as a non-seed", tr_peerIoAddrStr(&atom->addr,atom->port) );
atom->flags &= ~ADDED_F_SEED_FLAG;
} break;
}
case TR_PEERMSG_CLIENT_BLOCK:
broadcastGotBlock( t, e->pieceIndex, e->offset, e->length );
break;
case TR_PEERMSG_GOT_ASSERT_ERROR:
addStrike( t, peer );
peer->doPurge = 1;
break;
case TR_PEERMSG_GOT_ERROR:
peer->doPurge = 1;
break;
default:
assert(0);
}
torrentUnlock( t );
}
static void
ensureAtomExists( Torrent * t, const struct in_addr * addr, uint16_t port, uint8_t flags, uint8_t from )
{
if( getExistingAtom( t, addr ) == NULL )
{
struct peer_atom * a;
a = tr_new0( struct peer_atom, 1 );
a->addr = *addr;
a->port = port;
a->flags = flags;
a->from = from;
tordbg( t, "got a new atom: %s", tr_peerIoAddrStr(&a->addr,a->port) );
tr_ptrArrayInsertSorted( t->pool, a, comparePeerAtoms );
}
}
/* FIXME: this is kind of a mess. */
static void
myHandshakeDoneCB( tr_handshake * handshake,
tr_peerIo * io,
int isConnected,
const uint8_t * peer_id,
void * vmanager )
{
int ok = isConnected;
uint16_t port;
const struct in_addr * addr;
tr_peerMgr * manager = (tr_peerMgr*) vmanager;
Torrent * t;
tr_handshake * ours;
assert( io != NULL );
assert( isConnected==0 || isConnected==1 );
t = tr_peerIoHasTorrentHash( io )
? getExistingTorrent( manager, tr_peerIoGetTorrentHash( io ) )
: NULL;
if( tr_peerIoIsIncoming ( io ) )
ours = tr_ptrArrayRemoveSorted( manager->incomingHandshakes,
handshake, handshakeCompare );
else if( t != NULL )
ours = tr_ptrArrayRemoveSorted( t->outgoingHandshakes,
handshake, handshakeCompare );
else
ours = handshake;
assert( ours != NULL );
assert( ours == handshake );
if( t != NULL )
torrentLock( t );
addr = tr_peerIoGetAddress( io, &port );
if( !ok || !t || !t->isRunning )
{
if( t ) {
struct peer_atom * atom = getExistingAtom( t, addr );
if( atom )
++atom->numFails;
}
tr_peerIoFree( io );
}
else /* looking good */
{
struct peer_atom * atom;
ensureAtomExists( t, addr, port, 0, TR_PEER_FROM_INCOMING );
atom = getExistingAtom( t, addr );
if( atom->myflags & MYFLAG_BANNED )
{
tordbg( t, "banned peer %s tried to reconnect", tr_peerIoAddrStr(&atom->addr,atom->port) );
tr_peerIoFree( io );
}
else if( tr_ptrArraySize( t->peers ) >= t->tor->maxConnectedPeers )
{
tr_peerIoFree( io );
}
else
{
tr_peer * peer = getExistingPeer( t, addr );
if( peer != NULL ) /* we already have this peer */
{
tr_peerIoFree( io );
}
else
{
peer = getPeer( t, addr );
tr_free( peer->client );
peer->client = peer_id ? tr_clientForId( peer_id ) : NULL;
peer->port = port;
peer->io = io;
peer->msgs = tr_peerMsgsNew( t->tor, peer, msgsCallbackFunc, t, &peer->msgsTag );
atom->time = time( NULL );
}
}
}
if( t != NULL )
torrentUnlock( t );
}
void
tr_peerMgrAddIncoming( tr_peerMgr * manager,
struct in_addr * addr,
uint16_t port,
int socket )
{
managerLock( manager );
if( getExistingHandshake( manager->incomingHandshakes, addr ) )
{
tr_netClose( socket );
}
else /* we don't have a connetion to them yet... */
{
tr_peerIo * io;
tr_handshake * handshake;
tordbg( NULL, "Got an INCOMING connection with %s", tr_peerIoAddrStr( addr, port ) );
io = tr_peerIoNewIncoming( manager->handle, addr, port, socket );
handshake = tr_handshakeNew( io,
manager->handle->encryptionMode,
myHandshakeDoneCB,
manager );
tr_ptrArrayInsertSorted( manager->incomingHandshakes, handshake, handshakeCompare );
}
managerUnlock( manager );
}
void
tr_peerMgrAddPex( tr_peerMgr * manager,
const uint8_t * torrentHash,
uint8_t from,
const tr_pex * pex )
{
Torrent * t;
managerLock( manager );
t = getExistingTorrent( manager, torrentHash );
ensureAtomExists( t, &pex->in_addr, pex->port, pex->flags, from );
managerUnlock( manager );
}
void
tr_peerMgrAddPeers( tr_peerMgr * manager,
const uint8_t * torrentHash,
uint8_t from,
const uint8_t * peerCompact,
int peerCount )
{
int i;
const uint8_t * walk = peerCompact;
Torrent * t;
managerLock( manager );
t = getExistingTorrent( manager, torrentHash );
for( i=0; t!=NULL && i<peerCount; ++i )
{
struct in_addr addr;
uint16_t port;
memcpy( &addr, walk, 4 ); walk += 4;
memcpy( &port, walk, 2 ); walk += 2;
ensureAtomExists( t, &addr, port, 0, from );
}
managerUnlock( manager );
}
/**
***
**/
void
tr_peerMgrSetBlame( tr_peerMgr * manager,
const uint8_t * torrentHash,
int pieceIndex,
int success )
{
if( !success )
{
int peerCount, i;
Torrent * t = getExistingTorrent( manager, torrentHash );
tr_peer ** peers;
assert( torrentIsLocked( t ) );
peers = (tr_peer **) tr_ptrArrayPeek( t->peers, &peerCount );
for( i=0; i<peerCount; ++i )
{
tr_peer * peer = peers[i];
if( tr_bitfieldHas( peer->blame, pieceIndex ) )
{
tordbg( t, "peer %s contributed to corrupt piece (%d); now has %d strikes",
tr_peerIoAddrStr(&peer->in_addr,peer->port),
pieceIndex, (int)peer->strikes+1 );
addStrike( t, peer );
}
}
}
}
int
tr_pexCompare( const void * va, const void * vb )
{
const tr_pex * a = (const tr_pex *) va;
const tr_pex * b = (const tr_pex *) vb;
int i = memcmp( &a->in_addr, &b->in_addr, sizeof(struct in_addr) );
if( i ) return i;
if( a->port < b->port ) return -1;
if( a->port > b->port ) return 1;
return 0;
}
int tr_pexCompare( const void * a, const void * b );
static int
peerPrefersCrypto( const tr_peer * peer )
{
if( peer->encryption_preference == ENCRYPTION_PREFERENCE_YES )
return TRUE;
if( peer->encryption_preference == ENCRYPTION_PREFERENCE_NO )
return FALSE;
return tr_peerIoIsEncrypted( peer->io );
};
int
tr_peerMgrGetPeers( tr_peerMgr * manager,
const uint8_t * torrentHash,
tr_pex ** setme_pex )
{
const Torrent * t = getExistingTorrent( (tr_peerMgr*)manager, torrentHash );
int i, peerCount;
const tr_peer ** peers;
tr_pex * pex;
tr_pex * walk;
torrentLock( (Torrent*)t );
peers = (const tr_peer **) tr_ptrArrayPeek( t->peers, &peerCount );
pex = walk = tr_new( tr_pex, peerCount );
for( i=0; i<peerCount; ++i, ++walk )
{
const tr_peer * peer = peers[i];
walk->in_addr = peer->in_addr;
walk->port = peer->port;
walk->flags = 0;
if( peerPrefersCrypto(peer) ) walk->flags |= ADDED_F_ENCRYPTION_FLAG;
if( peer->progress >= 1.0 ) walk->flags |= ADDED_F_SEED_FLAG;
}
assert( ( walk - pex ) == peerCount );
qsort( pex, peerCount, sizeof(tr_pex), tr_pexCompare );
*setme_pex = pex;
torrentUnlock( (Torrent*)t );
return peerCount;
}
static int reconnectPulse( void * vtorrent );
static int rechokePulse( void * vtorrent );
static int swiftPulse( void * vtorrent );
void
tr_peerMgrStartTorrent( tr_peerMgr * manager,
const uint8_t * torrentHash )
{
Torrent * t;
managerLock( manager );
t = getExistingTorrent( manager, torrentHash );
assert( t != NULL );
assert( ( t->isRunning != 0 ) == ( t->reconnectTimer != NULL ) );
assert( ( t->isRunning != 0 ) == ( t->rechokeTimer != NULL ) );
assert( ( t->isRunning != 0 ) == ( t->swiftTimer != NULL ) );
if( !t->isRunning )
{
t->isRunning = 1;
t->reconnectTimer = tr_timerNew( t->manager->handle,
reconnectPulse, t,
RECONNECT_PERIOD_MSEC );
t->rechokeTimer = tr_timerNew( t->manager->handle,
rechokePulse, t,
RECHOKE_PERIOD_MSEC );
t->swiftTimer = tr_timerNew( t->manager->handle,
swiftPulse, t,
SWIFT_PERIOD_MSEC );
reconnectPulse( t );
rechokePulse( t );
swiftPulse( t );
}
managerUnlock( manager );
}
static void
stopTorrent( Torrent * t )
{
assert( torrentIsLocked( t ) );
t->isRunning = 0;
tr_timerFree( &t->rechokeTimer );
tr_timerFree( &t->reconnectTimer );
tr_timerFree( &t->swiftTimer );
/* disconnect the peers. */
tr_ptrArrayForeach( t->peers, (PtrArrayForeachFunc)peerDestructor );
tr_ptrArrayClear( t->peers );
/* disconnect the handshakes. handshakeAbort calls handshakeDoneCB(),
* which removes the handshake from t->outgoingHandshakes... */
while( !tr_ptrArrayEmpty( t->outgoingHandshakes ) )
tr_handshakeAbort( tr_ptrArrayNth( t->outgoingHandshakes, 0 ) );
}
void
tr_peerMgrStopTorrent( tr_peerMgr * manager,
const uint8_t * torrentHash)
{
managerLock( manager );
stopTorrent( getExistingTorrent( manager, torrentHash ) );
managerUnlock( manager );
}
void
tr_peerMgrAddTorrent( tr_peerMgr * manager,
tr_torrent * tor )
{
Torrent * t;
managerLock( manager );
assert( tor != NULL );
assert( getExistingTorrent( manager, tor->info.hash ) == NULL );
t = torrentConstructor( manager, tor );
tr_ptrArrayInsertSorted( manager->torrents, t, torrentCompare );
managerUnlock( manager );
}
void
tr_peerMgrRemoveTorrent( tr_peerMgr * manager,
const uint8_t * torrentHash )
{
Torrent * t;
managerLock( manager );
t = getExistingTorrent( manager, torrentHash );
assert( t != NULL );
stopTorrent( t );
tr_ptrArrayRemoveSorted( manager->torrents, t, torrentCompare );
torrentDestructor( t );
managerUnlock( manager );
}
void
tr_peerMgrTorrentAvailability( const tr_peerMgr * manager,
const uint8_t * torrentHash,
int8_t * tab,
int tabCount )
{
int i;
const Torrent * t;
const tr_torrent * tor;
float interval;
managerLock( (tr_peerMgr*)manager );
t = getExistingTorrent( (tr_peerMgr*)manager, torrentHash );
tor = t->tor;
interval = tor->info.pieceCount / (float)tabCount;
memset( tab, 0, tabCount );
for( i=0; i<tabCount; ++i )
{
const int piece = i * interval;
if( tor == NULL )
tab[i] = 0;
else if( tr_cpPieceIsComplete( tor->completion, piece ) )
tab[i] = -1;
else {
int j, peerCount;
const tr_peer ** peers = (const tr_peer **) tr_ptrArrayPeek( t->peers, &peerCount );
for( j=0; j<peerCount; ++j )
if( tr_bitfieldHas( peers[j]->have, i ) )
++tab[i];
}
}
managerUnlock( (tr_peerMgr*)manager );
}
/* Returns the pieces that we and/or a connected peer has */
tr_bitfield*
tr_peerMgrGetAvailable( const tr_peerMgr * manager,
const uint8_t * torrentHash )
{
int i, size;
const Torrent * t;
const tr_peer ** peers;
tr_bitfield * pieces;
managerLock( (tr_peerMgr*)manager );
t = getExistingTorrent( (tr_peerMgr*)manager, torrentHash );
peers = (const tr_peer **) tr_ptrArrayPeek( t->peers, &size );
pieces = tr_bitfieldDup( tr_cpPieceBitfield( t->tor->completion ) );
for( i=0; i<size; ++i )
if( peers[i]->io != NULL )
tr_bitfieldOr( pieces, peers[i]->have );
managerUnlock( (tr_peerMgr*)manager );
return pieces;
}
int
tr_peerMgrHasConnections( const tr_peerMgr * manager,
const uint8_t * torrentHash )
{
int ret;
const Torrent * t;
managerLock( (tr_peerMgr*)manager );
t = getExistingTorrent( (tr_peerMgr*)manager, torrentHash );
ret = t && tr_ptrArraySize( t->peers );
managerUnlock( (tr_peerMgr*)manager );
return ret;
}
static int
clientIsDownloadingFrom( const tr_peer * peer )
{
return peer->clientIsInterested && !peer->clientIsChoked;
}
static int
clientIsUploadingTo( const tr_peer * peer )
{
return peer->peerIsInterested && !peer->peerIsChoked;
}
void
tr_peerMgrTorrentStats( const tr_peerMgr * manager,
const uint8_t * torrentHash,
int * setmePeersKnown,
int * setmePeersConnected,
int * setmePeersSendingToUs,
int * setmePeersGettingFromUs,
int * setmePeersFrom )
{
int i, size;
const Torrent * t;
const tr_peer ** peers;
managerLock( (tr_peerMgr*)manager );
t = getExistingTorrent( (tr_peerMgr*)manager, torrentHash );
peers = (const tr_peer **) tr_ptrArrayPeek( t->peers, &size );
*setmePeersKnown = tr_ptrArraySize( t->pool );
*setmePeersConnected = 0;
*setmePeersSendingToUs = 0;
*setmePeersGettingFromUs = 0;
for( i=0; i<TR_PEER_FROM__MAX; ++i )
setmePeersFrom[i] = 0;
for( i=0; i<size; ++i )
{
const tr_peer * peer = peers[i];
const struct peer_atom * atom = getExistingAtom( t, &peer->in_addr );
if( peer->io == NULL ) /* not connected */
continue;
++*setmePeersConnected;
++setmePeersFrom[atom->from];
if( clientIsDownloadingFrom( peer ) )
++*setmePeersSendingToUs;
if( clientIsUploadingTo( peer ) )
++*setmePeersGettingFromUs;
}
managerUnlock( (tr_peerMgr*)manager );
}
struct tr_peer_stat *
tr_peerMgrPeerStats( const tr_peerMgr * manager,
const uint8_t * torrentHash,
int * setmeCount UNUSED )
{
int i, size;
const Torrent * t;
tr_peer ** peers;
tr_peer_stat * ret;
assert( manager != NULL );
managerLock( (tr_peerMgr*)manager );
t = getExistingTorrent( (tr_peerMgr*)manager, torrentHash );
peers = getConnectedPeers( (Torrent*)t, &size );
ret = tr_new0( tr_peer_stat, size );
for( i=0; i<size; ++i )
{
char * pch;
const tr_peer * peer = peers[i];
const struct peer_atom * atom = getExistingAtom( t, &peer->in_addr );
tr_peer_stat * stat = ret + i;
tr_netNtop( &peer->in_addr, stat->addr, sizeof(stat->addr) );
strlcpy( stat->client, (peer->client ? peer->client : ""), sizeof(stat->client) );
stat->port = peer->port;
stat->from = atom->from;
stat->progress = peer->progress;
stat->isEncrypted = tr_peerIoIsEncrypted( peer->io ) ? 1 : 0;
stat->uploadToRate = peer->rateToPeer;
stat->downloadFromRate = peer->rateToClient;
stat->peerIsChoked = peer->peerIsChoked;
stat->peerIsInterested = peer->peerIsInterested;
stat->clientIsChoked = peer->clientIsChoked;
stat->clientIsInterested = peer->clientIsInterested;
stat->isIncoming = tr_peerIoIsIncoming( peer->io );
stat->isDownloadingFrom = clientIsDownloadingFrom( peer );
stat->isUploadingTo = clientIsUploadingTo( peer );
pch = stat->flagStr;
if( t->optimistic == peer ) *pch++ = 'O';
if( stat->isDownloadingFrom ) *pch++ = 'D';
else if( stat->clientIsInterested ) *pch++ = 'd';
if( stat->isUploadingTo ) *pch++ = 'U';
else if( stat->peerIsInterested ) *pch++ = 'u';
if( !stat->clientIsChoked && !stat->clientIsInterested ) *pch++ = 'K';
if( !stat->peerIsChoked && !stat->peerIsInterested ) *pch++ = '?';
if( stat->isEncrypted ) *pch++ = 'E';
if( stat->from == TR_PEER_FROM_PEX ) *pch++ = 'X';
if( stat->isIncoming ) *pch++ = 'I';
*pch = '\0';
}
*setmeCount = size;
tr_free( peers );
managerUnlock( (tr_peerMgr*)manager );
return ret;
}
/**
***
**/
struct ChokeData
{
uint8_t doUnchoke;
uint8_t isInterested;
uint32_t rate;
tr_peer * peer;
};
static int
compareChoke( const void * va, const void * vb )
{
const struct ChokeData * a = va;
const struct ChokeData * b = vb;
return -tr_compareUint32( a->rate, b->rate );
}
static int
isNew( const tr_peer * peer )
{
return peer && peer->io && tr_peerIoGetAge( peer->io ) < 45;
}
static int
isSame( const tr_peer * peer )
{
return peer && peer->client && strstr( peer->client, "Transmission" );
}
/**
***
**/
static double
getWeightedRate( const tr_peer * peer, int clientIsSeed )
{
return (int)( 10.0 * ( clientIsSeed ? peer->rateToPeer
: peer->rateToClient ) );
}
static void
rechoke( Torrent * t )
{
int i, n, peerCount, size, unchokedInterested;
tr_peer ** peers = getConnectedPeers( t, &peerCount );
struct ChokeData * choke = tr_new0( struct ChokeData, peerCount );
const int clientIsSeed = tr_torrentIsSeed( t->tor );
assert( torrentIsLocked( t ) );
/* sort the peers by preference and rate */
for( i=0, size=0; i<peerCount; ++i )
{
tr_peer * peer = peers[i];
if( peer->progress >= 1.0 ) /* choke all seeds */
tr_peerMsgsSetChoke( peer->msgs, TRUE );
else {
struct ChokeData * node = &choke[size++];
node->peer = peer;
node->isInterested = peer->peerIsInterested;
node->rate = getWeightedRate( peer, clientIsSeed );
}
}
qsort( choke, size, sizeof(struct ChokeData), compareChoke );
/**
* Reciprocation and number of uploads capping is managed by unchoking
* the N peers which have the best upload rate and are interested.
* This maximizes the client's download rate. These N peers are
* referred to as downloaders, because they are interested in downloading
* from the client.
*
* Peers which have a better upload rate (as compared to the downloaders)
* but aren't interested get unchoked. If they become interested, the
* downloader with the worst upload rate gets choked. If a client has
* a complete file, it uses its upload rate rather than its download
* rate to decide which peers to unchoke.
*/
unchokedInterested = 0;
for( i=0; i<size && unchokedInterested<t->tor->maxUnchokedPeers; ++i ) {
choke[i].doUnchoke = 1;
if( choke[i].isInterested )
++unchokedInterested;
}
n = i;
while( i<size )
choke[i++].doUnchoke = 0;
/* optimistic unchoke */
if( i < size )
{
struct ChokeData * c;
tr_ptrArray * randPool = tr_ptrArrayNew( );
for( ; i<size; ++i )
{
const tr_peer * peer = choke[i].peer;
int x=1, y;
if( isNew( peer ) ) x *= 3;
if( isSame( peer ) ) x *= 3;
for( y=0; y<x; ++y )
tr_ptrArrayAppend( randPool, choke );
}
i = tr_rand( tr_ptrArraySize( randPool ) );
c = ( struct ChokeData* )tr_ptrArrayNth( randPool, i);
c->doUnchoke = 1;
t->optimistic = c->peer;
tr_ptrArrayFree( randPool, NULL );
}
for( i=0; i<size; ++i )
tr_peerMsgsSetChoke( choke[i].peer->msgs, !choke[i].doUnchoke );
/* cleanup */
tr_free( choke );
tr_free( peers );
}
static int
rechokePulse( void * vtorrent )
{
Torrent * t = vtorrent;
torrentLock( t );
rechoke( t );
torrentUnlock( t );
return TRUE;
}
/***
****
***/
static int
swiftPulse( void * vtorrent )
{
Torrent * t = vtorrent;
torrentLock( t );
if( !tr_torrentIsSeed( t->tor ) )
{
int i;
int peerCount = 0;
int deadbeatCount = 0;
tr_peer ** peers = getConnectedPeers( t, &peerCount );
tr_peer ** deadbeats = tr_new( tr_peer*, peerCount );
const double ul_KiBsec = tr_rcRate( t->tor->upload );
const double ul_KiB = ul_KiBsec * (SWIFT_PERIOD_MSEC/1000.0);
const double ul_bytes = ul_KiB * 1024;
const double freeCreditTotal = ul_bytes * SWIFT_LARGESSE;
int freeCreditPerPeer;
for( i=0; i<peerCount; ++i ) {
tr_peer * peer = peers[i];
if( peer->credit <= 0 )
deadbeats[deadbeatCount++] = peer;
}
freeCreditPerPeer = (int)( freeCreditTotal / deadbeatCount );
for( i=0; i<deadbeatCount; ++i )
deadbeats[i]->credit = freeCreditPerPeer;
tordbg( t, "%d deadbeats, "
"who are each being granted %d bytes' credit "
"for a total of %.1f KiB, "
"%d%% of the torrent's ul speed %.1f\n",
deadbeatCount, freeCreditPerPeer,
ul_KiBsec*SWIFT_LARGESSE, (int)(SWIFT_LARGESSE*100), ul_KiBsec );
tr_free( deadbeats );
tr_free( peers );
}
torrentUnlock( t );
return TRUE;
}
/***
****
**** Life and Death
****
***/
static int
shouldPeerBeClosed( const Torrent * t, const tr_peer * peer, int peerCount )
{
const tr_torrent * tor = t->tor;
const time_t now = time( NULL );
const struct peer_atom * atom = getExistingAtom( t, &peer->in_addr );
/* if it's marked for purging, close it */
if( peer->doPurge ) {
tordbg( t, "purging peer %s because its doPurge flag is set", tr_peerIoAddrStr(&atom->addr,atom->port) );
return TRUE;
}
/* if we're both seeds and it's been long enough for a pex exchange, close it */
if( 1 ) {
const int clientIsSeed = tr_torrentIsSeed( tor );
const int peerIsSeed = atom->flags & ADDED_F_SEED_FLAG;
if( peerIsSeed && clientIsSeed && ( !tr_torrentAllowsPex(tor) || (now-atom->time>=30) ) ) {
tordbg( t, "purging peer %s because we're both seeds", tr_peerIoAddrStr(&atom->addr,atom->port) );
return TRUE;
}
}
/* disconnect if it's been too long since piece data has been transferred.
* this is on a sliding scale based on number of available peers... */
if( 1 ) {
const int relaxStrictnessIfFewerThanN = (int)((tor->maxConnectedPeers * 0.9) + 0.5);
/* if we have >= relaxIfFewerThan, strictness is 100%.
* if we have zero connections, strictness is 0% */
const double strictness = peerCount >= relaxStrictnessIfFewerThanN
? 1.0
: peerCount / (double)relaxStrictnessIfFewerThanN;
const int lo = MIN_UPLOAD_IDLE_SECS;
const int hi = MAX_UPLOAD_IDLE_SECS;
const int limit = lo + ((hi-lo) * strictness);
const time_t then = peer->pieceDataActivityDate;
const int idleTime = then ? (now-then) : 0;
if( idleTime > limit ) {
tordbg( t, "purging peer %s because it's been %d secs since we shared anything",
tr_peerIoAddrStr(&atom->addr,atom->port), idleTime );
return TRUE;
}
}
return FALSE;
}
static tr_peer **
getPeersToClose( Torrent * t, int * setmeSize )
{
int i, peerCount, outsize;
tr_peer ** peers = (tr_peer**) tr_ptrArrayPeek( t->peers, &peerCount );
struct tr_peer ** ret = tr_new( tr_peer*, peerCount );
assert( torrentIsLocked( t ) );
for( i=outsize=0; i<peerCount; ++i )
if( shouldPeerBeClosed( t, peers[i], peerCount ) )
ret[outsize++] = peers[i];
*setmeSize = outsize;
return ret;
}
static int
compareCandidates( const void * va, const void * vb )
{
const struct peer_atom * a = * (const struct peer_atom**) va;
const struct peer_atom * b = * (const struct peer_atom**) vb;
int i;
if( a->piece_data_time > b->piece_data_time ) return -1;
if( a->piece_data_time < b->piece_data_time ) return 1;
if(( i = tr_compareUint16( a->numFails, b->numFails )))
return i;
if( a->time != b->time )
return a->time < b->time ? -1 : 1;
return 0;
}
static struct peer_atom **
getPeerCandidates( Torrent * t, int * setmeSize )
{
int i, atomCount, retCount;
struct peer_atom ** atoms;
struct peer_atom ** ret;
const time_t now = time( NULL );
const int seed = tr_torrentIsSeed( t->tor );
assert( torrentIsLocked( t ) );
atoms = (struct peer_atom**) tr_ptrArrayPeek( t->pool, &atomCount );
ret = tr_new( struct peer_atom*, atomCount );
for( i=retCount=0; i<atomCount; ++i )
{
struct peer_atom * atom = atoms[i];
/* peer fed us too much bad data ... we only keep it around
* now to weed it out in case someone sends it to us via pex */
if( atom->myflags & MYFLAG_BANNED )
continue;
/* peer was unconnectable before, so we're not going to keep trying.
* this is needs a separate flag from `banned', since if they try
* to connect to us later, we'll let them in */
if( atom->myflags & MYFLAG_UNREACHABLE )
continue;
/* we don't need two connections to the same peer... */
if( peerIsInUse( t, &atom->addr ) )
continue;
/* no need to connect if we're both seeds... */
if( seed && (atom->flags & ADDED_F_SEED_FLAG) )
continue;
/* we're wasting our time trying to connect to this bozo. */
if( atom->numFails > 3 )
continue;
/* If we were connected to this peer recently and transferring
* piece data, try to reconnect -- network troubles may have
* disconnected us. but if we weren't sharing piece data,
* hold off on this peer to give another one a try instead */
if( ( now - atom->piece_data_time ) > 30 )
{
int minWait = (60 * 5); /* five minutes */
int maxWait = (60 * 30); /* thirty minutes */
int wait = atom->numFails * minWait;
if( wait < minWait ) wait = minWait;
if( wait > maxWait ) wait = maxWait;
if( ( now - atom->time ) < wait ) {
tordbg( t, "RECONNECT peer %d (%s) is in its grace period of %d seconds..",
i, tr_peerIoAddrStr(&atom->addr,atom->port), wait );
continue;
}
}
ret[retCount++] = atom;
}
qsort( ret, retCount, sizeof(struct peer_atom*), compareCandidates );
*setmeSize = retCount;
return ret;
}
static int
reconnectPulse( void * vtorrent )
{
Torrent * t = vtorrent;
static time_t prevTime = 0;
static int newConnectionsThisSecond = 0;
time_t now;
torrentLock( t );
now = time( NULL );
if( prevTime != now )
{
prevTime = now;
newConnectionsThisSecond = 0;
}
if( !t->isRunning )
{
removeAllPeers( t );
}
else
{
int i, nCandidates, nBad;
struct peer_atom ** candidates = getPeerCandidates( t, &nCandidates );
struct tr_peer ** connections = getPeersToClose( t, &nBad );
if( nBad || nCandidates )
tordbg( t, "reconnect pulse for [%s]: %d bad connections, "
"%d connection candidates, %d atoms, max per pulse is %d",
t->tor->info.name, nBad, nCandidates,
tr_ptrArraySize(t->pool),
(int)MAX_RECONNECTIONS_PER_PULSE );
/* disconnect some peers.
if we got transferred piece data, then they might be good peers,
so reset their `numFails' weight to zero. otherwise we connected
to them fruitlessly, so mark it as another fail */
for( i=0; i<nBad; ++i ) {
tr_peer * peer = connections[i];
struct peer_atom * atom = getExistingAtom( t, &peer->in_addr );
if( peer->pieceDataActivityDate )
atom->numFails = 0;
else
++atom->numFails;
removePeer( t, peer );
}
/* add some new ones */
for( i=0; i < nCandidates
&& i < MAX_RECONNECTIONS_PER_PULSE
&& newConnectionsThisSecond < MAX_CONNECTIONS_PER_SECOND; ++i )
{
tr_peerMgr * mgr = t->manager;
struct peer_atom * atom = candidates[i];
tr_peerIo * io;
tordbg( t, "Starting an OUTGOING connection with %s",
tr_peerIoAddrStr( &atom->addr, atom->port ) );
io = tr_peerIoNewOutgoing( mgr->handle, &atom->addr, atom->port, t->hash );
if( io == NULL )
{
atom->myflags |= MYFLAG_UNREACHABLE;
}
else
{
tr_handshake * handshake = tr_handshakeNew( io,
mgr->handle->encryptionMode,
myHandshakeDoneCB,
mgr );
assert( tr_peerIoGetTorrentHash( io ) != NULL );
++newConnectionsThisSecond;
tr_ptrArrayInsertSorted( t->outgoingHandshakes, handshake, handshakeCompare );
}
atom->time = time( NULL );
}
/* cleanup */
tr_free( connections );
tr_free( candidates );
}
torrentUnlock( t );
return TRUE;
}
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