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transmission/libtransmission/peer-msgs.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 <errno.h>
#include <limits.h> /* INT_MAX */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <libgen.h> /* basename */
#include <event.h>
#include "transmission.h"
#include "bencode.h"
#include "completion.h"
#include "inout.h"
#include "peer-io.h"
#include "peer-mgr.h"
#include "peer-mgr-private.h"
#include "peer-msgs.h"
#include "ratecontrol.h"
#include "stats.h"
#include "torrent.h"
#include "trevent.h"
#include "utils.h"
/**
***
**/
enum
{
BT_CHOKE = 0,
BT_UNCHOKE = 1,
BT_INTERESTED = 2,
BT_NOT_INTERESTED = 3,
BT_HAVE = 4,
BT_BITFIELD = 5,
BT_REQUEST = 6,
BT_PIECE = 7,
BT_CANCEL = 8,
BT_PORT = 9,
BT_SUGGEST = 13,
BT_HAVE_ALL = 14,
BT_HAVE_NONE = 15,
BT_REJECT = 16,
BT_ALLOWED_FAST = 17,
BT_LTEP = 20,
LTEP_HANDSHAKE = 0,
TR_LTEP_PEX = 1,
MIN_CHOKE_PERIOD_SEC = (10),
/* idle seconds before we send a keepalive */
KEEPALIVE_INTERVAL_SECS = 90,
PEX_INTERVAL = (90 * 1000), /* msec between sendPex() calls */
PEER_PULSE_INTERVAL = (50), /* msec between pulse() calls */
RATE_PULSE_INTERVAL = (250), /* msec between ratePulse() calls */
MAX_QUEUE_SIZE = (100),
/* (fast peers) max number of pieces we fast-allow to another peer */
MAX_FAST_ALLOWED_COUNT = 10,
/* (fast peers) max threshold for allowing fast-pieces requests */
MAX_FAST_ALLOWED_THRESHOLD = 10,
/* how long an unsent request can stay queued before it's returned
back to the peer-mgr's pool of requests */
QUEUED_REQUEST_TTL_SECS = 20,
/* how long a sent request can stay queued before it's returned
back to the peer-mgr's pool of requests */
SENT_REQUEST_TTL_SECS = 120
};
/**
*** REQUEST MANAGEMENT
**/
enum
{
AWAITING_BT_LENGTH,
AWAITING_BT_ID,
AWAITING_BT_MESSAGE,
AWAITING_BT_PIECE
};
struct peer_request
{
uint32_t index;
uint32_t offset;
uint32_t length;
time_t time_requested;
};
static int
compareRequest( const void * va, const void * vb )
{
int i;
const struct peer_request * a = va;
const struct peer_request * b = vb;
if(( i = tr_compareUint32( a->index, b->index ))) return i;
if(( i = tr_compareUint32( a->offset, b->offset ))) return i;
if(( i = tr_compareUint32( a->length, b->length ))) return i;
return 0;
}
struct request_list
{
uint16_t count;
uint16_t max;
struct peer_request * requests;
};
static const struct request_list REQUEST_LIST_INIT = { 0, 0, NULL };
static void
reqListReserve( struct request_list * list, uint16_t max )
{
if( list->max < max )
{
list->max = max;
list->requests = tr_renew( struct peer_request,
list->requests,
list->max );
}
}
static void
reqListClear( struct request_list * list )
{
tr_free( list->requests );
*list = REQUEST_LIST_INIT;
}
static void
reqListCopy( struct request_list * dest, const struct request_list * src )
{
dest->count = src->count;
dest->max = src->max;
dest->requests = tr_new( struct peer_request, dest->max );
memcpy( dest->requests, src->requests, sizeof( struct peer_request ) * dest->count );
}
static void
reqListRemoveOne( struct request_list * list, int i )
{
assert( 0<=i && i<list->count );
memmove( &list->requests[i],
&list->requests[i+1],
sizeof( struct peer_request ) * ( --list->count - i ) );
}
static void
reqListAppend( struct request_list * list, const struct peer_request * req )
{
if( ++list->count >= list->max )
reqListReserve( list, list->max + 8 );
list->requests[list->count-1] = *req;
}
static tr_errno
reqListPop( struct request_list * list, struct peer_request * setme )
{
tr_errno err;
if( !list->count )
err = TR_ERROR;
else {
*setme = list->requests[0];
reqListRemoveOne( list, 0 );
err = TR_OK;
}
return err;
}
static int
reqListFind( struct request_list * list, const struct peer_request * key )
{
uint16_t i;
for( i=0; i<list->count; ++i )
if( !compareRequest( key, list->requests+i ) )
return i;
return -1;
}
static tr_errno
reqListRemove( struct request_list * list, const struct peer_request * key )
{
tr_errno err;
const int i = reqListFind( list, key );
if( i < 0 )
err = TR_ERROR;
else {
err = TR_OK;
reqListRemoveOne( list, i );
}
return err;
}
/**
***
**/
/* this is raw, unchanged data from the peer regarding
* the current message that it's sending us. */
struct tr_incoming
{
uint8_t id;
uint32_t length; /* includes the +1 for id length */
struct peer_request blockReq; /* metadata for incoming blocks */
struct evbuffer * block; /* piece data for incoming blocks */
};
struct tr_peermsgs
{
unsigned int peerSentBitfield : 1;
unsigned int peerSupportsPex : 1;
unsigned int clientSentLtepHandshake : 1;
unsigned int peerSentLtepHandshake : 1;
unsigned int sendingBlock : 1;
uint8_t state;
uint8_t ut_pex_id;
uint16_t pexCount;
uint16_t maxActiveRequests;
uint16_t minActiveRequests;
tr_peer * info;
tr_handle * handle;
tr_torrent * torrent;
tr_peerIo * io;
tr_publisher_t * publisher;
struct evbuffer * outBlock; /* buffer of the current piece message */
struct evbuffer * outMessages; /* buffer of all the non-piece messages */
struct request_list peerAskedFor;
struct request_list peerAskedForFast;
struct request_list clientAskedFor;
struct request_list clientWillAskFor;
tr_timer * rateTimer;
tr_timer * pulseTimer;
tr_timer * pexTimer;
time_t clientSentPexAt;
time_t clientSentAnythingAt;
tr_bitfield * peerAllowedPieces;
struct tr_incoming incoming;
tr_pex * pex;
};
/**
***
**/
static void
myDebug( const char * file, int line,
const struct tr_peermsgs * msgs,
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] %s - %s [%s]: ",
tr_getLogTimeStr( timestr, sizeof(timestr) ),
msgs->torrent->info.name,
tr_peerIoGetAddrStr( msgs->io ),
msgs->info->client );
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 dbgmsg(msgs, fmt...) myDebug(__FILE__, __LINE__, msgs, ##fmt )
/**
***
**/
static void
protocolSendRequest( tr_peermsgs * msgs, const struct peer_request * req )
{
tr_peerIo * io = msgs->io;
struct evbuffer * out = msgs->outMessages;
dbgmsg( msgs, "requesting %u:%u->%u", req->index, req->offset, req->length );
tr_peerIoWriteUint32( io, out, sizeof(uint8_t) + 3*sizeof(uint32_t) );
tr_peerIoWriteUint8 ( io, out, BT_REQUEST );
tr_peerIoWriteUint32( io, out, req->index );
tr_peerIoWriteUint32( io, out, req->offset );
tr_peerIoWriteUint32( io, out, req->length );
}
static void
protocolSendCancel( tr_peermsgs * msgs, const struct peer_request * req )
{
tr_peerIo * io = msgs->io;
struct evbuffer * out = msgs->outMessages;
dbgmsg( msgs, "cancelling %u:%u->%u", req->index, req->offset, req->length );
tr_peerIoWriteUint32( io, out, sizeof(uint8_t) + 3*sizeof(uint32_t) );
tr_peerIoWriteUint8 ( io, out, BT_CANCEL );
tr_peerIoWriteUint32( io, out, req->index );
tr_peerIoWriteUint32( io, out, req->offset );
tr_peerIoWriteUint32( io, out, req->length );
}
static void
protocolSendHave( tr_peermsgs * msgs, uint32_t index )
{
tr_peerIo * io = msgs->io;
struct evbuffer * out = msgs->outMessages;
dbgmsg( msgs, "sending Have %u", index );
tr_peerIoWriteUint32( io, out, sizeof(uint8_t) + sizeof(uint32_t) );
tr_peerIoWriteUint8 ( io, out, BT_HAVE );
tr_peerIoWriteUint32( io, out, index );
}
static void
protocolSendChoke( tr_peermsgs * msgs, int choke )
{
tr_peerIo * io = msgs->io;
struct evbuffer * out = msgs->outMessages;
dbgmsg( msgs, "sending %s", (choke ? "Choke" : "Unchoke") );
tr_peerIoWriteUint32( io, out, sizeof(uint8_t) );
tr_peerIoWriteUint8 ( io, out, choke ? BT_CHOKE : BT_UNCHOKE );
}
/**
*** EVENTS
**/
static const tr_peermsgs_event blankEvent = { 0, 0, 0, 0, 0.0f, 0 };
static void
publish( tr_peermsgs * msgs, tr_peermsgs_event * e )
{
tr_publisherPublish( msgs->publisher, msgs->info, e );
}
static void
fireError( tr_peermsgs * msgs, tr_errno err )
{
tr_peermsgs_event e = blankEvent;
e.eventType = TR_PEERMSG_ERROR;
e.err = err;
publish( msgs, &e );
}
static void
fireNeedReq( tr_peermsgs * msgs )
{
tr_peermsgs_event e = blankEvent;
e.eventType = TR_PEERMSG_NEED_REQ;
publish( msgs, &e );
}
static void
firePeerProgress( tr_peermsgs * msgs )
{
tr_peermsgs_event e = blankEvent;
e.eventType = TR_PEERMSG_PEER_PROGRESS;
e.progress = msgs->info->progress;
publish( msgs, &e );
}
static void
fireClientHave( tr_peermsgs * msgs, uint32_t pieceIndex )
{
tr_peermsgs_event e = blankEvent;
e.eventType = TR_PEERMSG_CLIENT_HAVE;
e.pieceIndex = pieceIndex;
publish( msgs, &e );
}
static void
fireGotBlock( tr_peermsgs * msgs, const struct peer_request * req )
{
tr_peermsgs_event e = blankEvent;
e.eventType = TR_PEERMSG_CLIENT_BLOCK;
e.pieceIndex = req->index;
e.offset = req->offset;
e.length = req->length;
publish( msgs, &e );
}
static void
firePieceData( tr_peermsgs * msgs )
{
tr_peermsgs_event e = blankEvent;
e.eventType = TR_PEERMSG_PIECE_DATA;
publish( msgs, &e );
}
static void
fireCancelledReq( tr_peermsgs * msgs, const struct peer_request * req )
{
tr_peermsgs_event e = blankEvent;
e.eventType = TR_PEERMSG_CANCEL;
e.pieceIndex = req->index;
e.offset = req->offset;
e.length = req->length;
publish( msgs, &e );
}
/**
*** INTEREST
**/
static int
isPieceInteresting( const tr_peermsgs * peer,
int piece )
{
const tr_torrent * torrent = peer->torrent;
return ( ( !torrent->info.pieces[piece].dnd ) /* we want it */
&& ( !tr_cpPieceIsComplete( torrent->completion, piece ) ) /* !have */
&& ( tr_bitfieldHas( peer->info->have, piece ) ) ); /* peer has it */
}
/* "interested" means we'll ask for piece data if they unchoke us */
static int
isPeerInteresting( const tr_peermsgs * msgs )
{
tr_piece_index_t i;
const tr_torrent * torrent;
const tr_bitfield * bitfield;
const int clientIsSeed = tr_torrentIsSeed( msgs->torrent );
if( clientIsSeed )
return FALSE;
torrent = msgs->torrent;
bitfield = tr_cpPieceBitfield( torrent->completion );
if( !msgs->info->have )
return TRUE;
assert( bitfield->len == msgs->info->have->len );
for( i=0; i<torrent->info.pieceCount; ++i )
if( isPieceInteresting( msgs, i ) )
return TRUE;
return FALSE;
}
static void
sendInterest( tr_peermsgs * msgs, int weAreInterested )
{
assert( msgs != NULL );
assert( weAreInterested==0 || weAreInterested==1 );
msgs->info->clientIsInterested = weAreInterested;
dbgmsg( msgs, "Sending %s",
weAreInterested ? "Interested" : "Not Interested");
tr_peerIoWriteUint32( msgs->io, msgs->outMessages, sizeof(uint8_t) );
tr_peerIoWriteUint8 ( msgs->io, msgs->outMessages,
weAreInterested ? BT_INTERESTED : BT_NOT_INTERESTED );
}
static void
updateInterest( tr_peermsgs * msgs )
{
const int i = isPeerInteresting( msgs );
if( i != msgs->info->clientIsInterested )
sendInterest( msgs, i );
if( i )
fireNeedReq( msgs );
}
static void
cancelAllRequestsToClientExceptFast( tr_peermsgs * msgs )
{
reqListClear( &msgs->peerAskedFor );
}
void
tr_peerMsgsSetChoke( tr_peermsgs * msgs, int choke )
{
const time_t fibrillationTime = time(NULL) - MIN_CHOKE_PERIOD_SEC;
assert( msgs != NULL );
assert( msgs->info != NULL );
assert( choke==0 || choke==1 );
if( msgs->info->chokeChangedAt > fibrillationTime )
{
dbgmsg( msgs, "Not changing choke to %d to avoid fibrillation", choke );
}
else if( msgs->info->peerIsChoked != choke )
{
msgs->info->peerIsChoked = choke;
if( choke )
cancelAllRequestsToClientExceptFast( msgs );
protocolSendChoke( msgs, choke );
msgs->info->chokeChangedAt = time( NULL );
}
}
/**
***
**/
void
tr_peerMsgsHave( tr_peermsgs * msgs,
uint32_t index )
{
protocolSendHave( msgs, index );
/* since we have more pieces now, we might not be interested in this peer */
updateInterest( msgs );
}
#if 0
static void
sendFastSuggest( tr_peermsgs * msgs,
uint32_t pieceIndex )
{
assert( msgs != NULL );
if( tr_peerIoSupportsFEXT( msgs->io ) )
{
tr_peerIoWriteUint32( msgs->io, msgs->outMessages, sizeof(uint8_t) + sizeof(uint32_t) );
tr_peerIoWriteUint8( msgs->io, msgs->outMessages, BT_SUGGEST );
tr_peerIoWriteUint32( msgs->io, msgs->outMessages, pieceIndex );
}
}
static void
sendFastHave( tr_peermsgs * msgs, int all )
{
assert( msgs != NULL );
if( tr_peerIoSupportsFEXT( msgs->io ) )
{
tr_peerIoWriteUint32( msgs->io, msgs->outMessages, sizeof(uint8_t) );
tr_peerIoWriteUint8( msgs->io, msgs->outMessages, ( all ? BT_HAVE_ALL
: BT_HAVE_NONE ) );
updateInterest( msgs );
}
}
#endif
static void
sendFastReject( tr_peermsgs * msgs,
uint32_t pieceIndex,
uint32_t offset,
uint32_t length )
{
assert( msgs != NULL );
if( tr_peerIoSupportsFEXT( msgs->io ) )
{
const uint32_t len = sizeof(uint8_t) + 3 * sizeof(uint32_t);
tr_peerIoWriteUint32( msgs->io, msgs->outMessages, len );
tr_peerIoWriteUint8( msgs->io, msgs->outMessages, BT_REJECT );
tr_peerIoWriteUint32( msgs->io, msgs->outMessages, pieceIndex );
tr_peerIoWriteUint32( msgs->io, msgs->outMessages, offset );
tr_peerIoWriteUint32( msgs->io, msgs->outMessages, length );
}
}
static tr_bitfield*
getPeerAllowedPieces( tr_peermsgs * msgs )
{
if( !msgs->peerAllowedPieces && tr_peerIoSupportsFEXT( msgs->io ) )
{
msgs->peerAllowedPieces = tr_peerMgrGenerateAllowedSet(
MAX_FAST_ALLOWED_COUNT,
msgs->torrent->info.pieceCount,
msgs->torrent->info.hash,
tr_peerIoGetAddress( msgs->io, NULL ) );
}
return msgs->peerAllowedPieces;
}
static void
sendFastAllowed( tr_peermsgs * msgs,
uint32_t pieceIndex)
{
assert( msgs != NULL );
if( tr_peerIoSupportsFEXT( msgs->io ) )
{
tr_peerIoWriteUint32( msgs->io, msgs->outMessages, sizeof(uint8_t) + sizeof(uint32_t) );
tr_peerIoWriteUint8( msgs->io, msgs->outMessages, BT_ALLOWED_FAST );
tr_peerIoWriteUint32( msgs->io, msgs->outMessages, pieceIndex );
}
}
static void
sendFastAllowedSet( tr_peermsgs * msgs )
{
tr_piece_index_t i = 0;
while (i <= msgs->torrent->info.pieceCount )
{
if ( tr_bitfieldHas( getPeerAllowedPieces( msgs ), i) )
sendFastAllowed( msgs, i );
i++;
}
}
static void
maybeSendFastAllowedSet( tr_peermsgs * msgs )
{
if( tr_bitfieldCountTrueBits( msgs->info->have ) <= MAX_FAST_ALLOWED_THRESHOLD )
sendFastAllowedSet( msgs );
}
/**
***
**/
static int
reqIsValid( const tr_peermsgs * msgs,
uint32_t index,
uint32_t offset,
uint32_t length )
{
return tr_torrentReqIsValid( msgs->torrent, index, offset, length );
}
static int
requestIsValid( const tr_peermsgs * msgs, const struct peer_request * req )
{
return reqIsValid( msgs, req->index, req->offset, req->length );
}
static void
expireOldRequests( tr_peermsgs * msgs )
{
int i;
time_t oldestAllowed;
struct request_list tmp = REQUEST_LIST_INIT;
/* cancel requests that have been queued for too long */
oldestAllowed = time( NULL ) - QUEUED_REQUEST_TTL_SECS;
reqListCopy( &tmp, &msgs->clientWillAskFor );
for( i=0; i<tmp.count; ++i ) {
const struct peer_request * req = &tmp.requests[i];
if( req->time_requested < oldestAllowed )
tr_peerMsgsCancel( msgs, req->index, req->offset, req->length );
}
reqListClear( &tmp );
/* cancel requests that were sent too long ago */
oldestAllowed = time( NULL ) - SENT_REQUEST_TTL_SECS;
reqListCopy( &tmp, &msgs->clientAskedFor );
for( i=0; i<tmp.count; ++i ) {
const struct peer_request * req = &tmp.requests[i];
if( req->time_requested < oldestAllowed )
tr_peerMsgsCancel( msgs, req->index, req->offset, req->length );
}
reqListClear( &tmp );
}
static void
pumpRequestQueue( tr_peermsgs * msgs )
{
const int max = msgs->maxActiveRequests;
const int min = msgs->minActiveRequests;
const time_t now = time( NULL );
int sent = 0;
int count = msgs->clientAskedFor.count;
struct peer_request req;
if( count > min )
return;
if( msgs->info->clientIsChoked )
return;
while( ( count < max ) && !reqListPop( &msgs->clientWillAskFor, &req ) )
{
assert( requestIsValid( msgs, &req ) );
assert( tr_bitfieldHas( msgs->info->have, req.index ) );
protocolSendRequest( msgs, &req );
req.time_requested = now;
reqListAppend( &msgs->clientAskedFor, &req );
++count;
++sent;
}
if( sent )
dbgmsg( msgs, "pump sent %d requests, now have %d active and %d queued",
sent,
msgs->clientAskedFor.count,
msgs->clientWillAskFor.count );
if( count < max )
fireNeedReq( msgs );
}
static int
pulse( void * vmsgs );
int
tr_peerMsgsAddRequest( tr_peermsgs * msgs,
uint32_t index,
uint32_t offset,
uint32_t length )
{
const int req_max = msgs->maxActiveRequests;
struct peer_request req;
assert( msgs != NULL );
assert( msgs->torrent != NULL );
assert( reqIsValid( msgs, index, offset, length ) );
/**
*** Reasons to decline the request
**/
/* don't send requests to choked clients */
if( msgs->info->clientIsChoked ) {
dbgmsg( msgs, "declining request because they're choking us" );
return TR_ADDREQ_CLIENT_CHOKED;
}
/* peer doesn't have this piece */
if( !tr_bitfieldHas( msgs->info->have, index ) )
return TR_ADDREQ_MISSING;
/* peer's queue is full */
if( msgs->clientWillAskFor.count >= req_max ) {
dbgmsg( msgs, "declining request because we're full" );
return TR_ADDREQ_FULL;
}
/* have we already asked for this piece? */
req.index = index;
req.offset = offset;
req.length = length;
if( reqListFind( &msgs->clientAskedFor, &req ) != -1 ) {
dbgmsg( msgs, "declining because it's a duplicate" );
return TR_ADDREQ_DUPLICATE;
}
if( reqListFind( &msgs->clientWillAskFor, &req ) != -1 ) {
dbgmsg( msgs, "declining because it's a duplicate" );
return TR_ADDREQ_DUPLICATE;
}
/**
*** Accept this request
**/
dbgmsg( msgs, "added req for piece %d, offset %d", (int)index, (int)offset );
req.time_requested = time( NULL );
reqListAppend( &msgs->clientWillAskFor, &req );
return TR_ADDREQ_OK;
}
static void
cancelAllRequestsToPeer( tr_peermsgs * msgs )
{
int i;
struct request_list a = msgs->clientWillAskFor;
struct request_list b = msgs->clientAskedFor;
msgs->clientAskedFor = REQUEST_LIST_INIT;
msgs->clientWillAskFor = REQUEST_LIST_INIT;
for( i=0; i<a.count; ++i )
fireCancelledReq( msgs, &a.requests[i] );
for( i=0; i<b.count; ++i ) {
fireCancelledReq( msgs, &b.requests[i] );
protocolSendCancel( msgs, &b.requests[i] );
}
reqListClear( &a );
reqListClear( &b );
}
void
tr_peerMsgsCancel( tr_peermsgs * msgs,
uint32_t pieceIndex,
uint32_t offset,
uint32_t length )
{
struct peer_request req;
assert( msgs != NULL );
assert( length > 0 );
/* have we asked the peer for this piece? */
req.index = pieceIndex;
req.offset = offset;
req.length = length;
/* if it's only in the queue and hasn't been sent yet, free it */
if( !reqListRemove( &msgs->clientWillAskFor, &req ) )
fireCancelledReq( msgs, &req );
/* if it's already been sent, send a cancel message too */
if( !reqListRemove( &msgs->clientAskedFor, &req ) ) {
protocolSendCancel( msgs, &req );
fireCancelledReq( msgs, &req );
}
}
/**
***
**/
static void
sendLtepHandshake( tr_peermsgs * msgs )
{
tr_benc val, *m;
char * buf;
int len;
int pex;
struct evbuffer * outbuf;
if( msgs->clientSentLtepHandshake )
return;
outbuf = evbuffer_new( );
dbgmsg( msgs, "sending an ltep handshake" );
msgs->clientSentLtepHandshake = 1;
/* decide if we want to advertise pex support */
if( !tr_torrentAllowsPex( msgs->torrent ) )
pex = 0;
else if( msgs->peerSentLtepHandshake )
pex = msgs->peerSupportsPex ? 1 : 0;
else
pex = 1;
tr_bencInitDict( &val, 4 );
tr_bencDictAddInt( &val, "e", msgs->handle->encryptionMode != TR_PLAINTEXT_PREFERRED );
tr_bencDictAddInt( &val, "p", tr_sessionGetPublicPort( msgs->handle ) );
tr_bencDictAddStr( &val, "v", TR_NAME " " USERAGENT_PREFIX );
m = tr_bencDictAddDict( &val, "m", 1 );
if( pex )
tr_bencDictAddInt( m, "ut_pex", TR_LTEP_PEX );
buf = tr_bencSave( &val, &len );
tr_peerIoWriteUint32( msgs->io, outbuf, 2*sizeof(uint8_t) + len );
tr_peerIoWriteUint8 ( msgs->io, outbuf, BT_LTEP );
tr_peerIoWriteUint8 ( msgs->io, outbuf, LTEP_HANDSHAKE );
tr_peerIoWriteBytes ( msgs->io, outbuf, buf, len );
tr_peerIoWriteBuf( msgs->io, outbuf );
dbgmsg( msgs, "here is the ltep handshake we sent [%*.*s]", len, len, buf );
/* cleanup */
tr_bencFree( &val );
tr_free( buf );
evbuffer_free( outbuf );
}
static void
parseLtepHandshake( tr_peermsgs * msgs, int len, struct evbuffer * inbuf )
{
tr_benc val, * sub;
uint8_t * tmp = tr_new( uint8_t, len );
tr_peerIoReadBytes( msgs->io, inbuf, tmp, len );
msgs->peerSentLtepHandshake = 1;
if( tr_bencLoad( tmp, len, &val, NULL ) || val.type!=TYPE_DICT ) {
dbgmsg( msgs, "GET extended-handshake, couldn't get dictionary" );
tr_free( tmp );
return;
}
dbgmsg( msgs, "here is the ltep handshake we got [%*.*s]", len, len, tmp );
/* does the peer prefer encrypted connections? */
if(( sub = tr_bencDictFindType( &val, "e", TYPE_INT )))
msgs->info->encryption_preference = sub->val.i
? ENCRYPTION_PREFERENCE_YES
: ENCRYPTION_PREFERENCE_NO;
/* check supported messages for utorrent pex */
msgs->peerSupportsPex = 0;
if(( sub = tr_bencDictFindType( &val, "m", TYPE_DICT ))) {
if(( sub = tr_bencDictFindType( sub, "ut_pex", TYPE_INT ))) {
msgs->ut_pex_id = (uint8_t) sub->val.i;
msgs->peerSupportsPex = msgs->ut_pex_id == 0 ? 0 : 1;
dbgmsg( msgs, "msgs->ut_pex is %d", (int)msgs->ut_pex_id );
}
}
/* get peer's listening port */
if(( sub = tr_bencDictFindType( &val, "p", TYPE_INT ))) {
msgs->info->port = htons( (uint16_t)sub->val.i );
dbgmsg( msgs, "msgs->port is now %hu", msgs->info->port );
}
tr_bencFree( &val );
tr_free( tmp );
}
static void
parseUtPex( tr_peermsgs * msgs, int msglen, struct evbuffer * inbuf )
{
int loaded = 0;
uint8_t * tmp = tr_new( uint8_t, msglen );
tr_benc val, *added;
const tr_torrent * tor = msgs->torrent;
tr_peerIoReadBytes( msgs->io, inbuf, tmp, msglen );
if( tr_torrentAllowsPex( tor )
&& (( loaded = !tr_bencLoad( tmp, msglen, &val, NULL )))
&& (( added = tr_bencDictFindType( &val, "added", TYPE_STR ))))
{
const char * added_f = NULL;
tr_pex * pex;
size_t i, n;
tr_bencDictFindStr( &val, "added.f", &added_f );
pex = tr_peerMgrCompactToPex( added->val.s.s, added->val.s.i, added_f, &n );
for( i=0; i<n; ++i )
tr_peerMgrAddPex( msgs->handle->peerMgr, tor->info.hash,
TR_PEER_FROM_PEX, pex+i );
tr_free( pex );
}
if( loaded )
tr_bencFree( &val );
tr_free( tmp );
}
static void
sendPex( tr_peermsgs * msgs );
static void
parseLtep( tr_peermsgs * msgs, int msglen, struct evbuffer * inbuf )
{
uint8_t ltep_msgid;
tr_peerIoReadUint8( msgs->io, inbuf, &ltep_msgid );
msglen--;
if( ltep_msgid == LTEP_HANDSHAKE )
{
dbgmsg( msgs, "got ltep handshake" );
parseLtepHandshake( msgs, msglen, inbuf );
if( tr_peerIoSupportsLTEP( msgs->io ) )
{
sendLtepHandshake( msgs );
sendPex( msgs );
}
}
else if( ltep_msgid == TR_LTEP_PEX )
{
dbgmsg( msgs, "got ut pex" );
msgs->peerSupportsPex = 1;
parseUtPex( msgs, msglen, inbuf );
}
else
{
dbgmsg( msgs, "skipping unknown ltep message (%d)", (int)ltep_msgid );
evbuffer_drain( inbuf, msglen );
}
}
static int
readBtLength( tr_peermsgs * msgs, struct evbuffer * inbuf, size_t inlen )
{
uint32_t len;
if( inlen < sizeof(len) )
return READ_MORE;
tr_peerIoReadUint32( msgs->io, inbuf, &len );
if( len == 0 ) /* peer sent us a keepalive message */
dbgmsg( msgs, "got KeepAlive" );
else {
msgs->incoming.length = len;
msgs->state = AWAITING_BT_ID;
}
return READ_AGAIN;
}
static int
readBtMessage( tr_peermsgs * msgs, struct evbuffer * inbuf, size_t inlen );
static int
readBtId( tr_peermsgs * msgs, struct evbuffer * inbuf, size_t inlen )
{
uint8_t id;
if( inlen < sizeof(uint8_t) )
return READ_MORE;
tr_peerIoReadUint8( msgs->io, inbuf, &id );
msgs->incoming.id = id;
if( id==BT_PIECE )
{
msgs->state = AWAITING_BT_PIECE;
return READ_AGAIN;
}
else if( msgs->incoming.length != 1 )
{
msgs->state = AWAITING_BT_MESSAGE;
return READ_AGAIN;
}
else return readBtMessage( msgs, inbuf, inlen-1 );
}
static void
updatePeerProgress( tr_peermsgs * msgs )
{
msgs->info->progress = tr_bitfieldCountTrueBits( msgs->info->have )
/ (float)msgs->torrent->info.pieceCount;
dbgmsg( msgs, "peer progress is %f", msgs->info->progress );
updateInterest( msgs );
firePeerProgress( msgs );
}
static int
clientCanSendFastBlock( const tr_peermsgs * msgs UNUSED )
{
/* don't send a fast piece if peer has MAX_FAST_ALLOWED_THRESHOLD pieces */
if( tr_bitfieldCountTrueBits( msgs->info->have ) > MAX_FAST_ALLOWED_THRESHOLD )
return FALSE;
/* ...or if we don't have ourself enough pieces */
if( tr_bitfieldCountTrueBits( tr_cpPieceBitfield( msgs->torrent->completion ) ) < MAX_FAST_ALLOWED_THRESHOLD )
return FALSE;
/* Maybe a bandwidth limit ? */
return TRUE;
}
static void
peerMadeRequest( tr_peermsgs * msgs, const struct peer_request * req )
{
const int reqIsValid = requestIsValid( msgs, req );
const int clientHasPiece = reqIsValid && tr_cpPieceIsComplete( msgs->torrent->completion, req->index );
const int peerIsChoked = msgs->info->peerIsChoked;
const int peerIsFast = tr_peerIoSupportsFEXT( msgs->io );
const int pieceIsFast = reqIsValid && tr_bitfieldHas( getPeerAllowedPieces( msgs ), req->index );
const int canSendFast = clientCanSendFastBlock( msgs );
if( !reqIsValid ) /* bad request */
{
dbgmsg( msgs, "rejecting an invalid request." );
sendFastReject( msgs, req->index, req->offset, req->length );
}
else if( !clientHasPiece ) /* we don't have it */
{
dbgmsg( msgs, "rejecting request for a piece we don't have." );
sendFastReject( msgs, req->index, req->offset, req->length );
}
else if( peerIsChoked && !peerIsFast ) /* doesn't he know he's choked? */
{
tr_peerMsgsSetChoke( msgs, 1 );
sendFastReject( msgs, req->index, req->offset, req->length );
}
else if( peerIsChoked && peerIsFast && ( !pieceIsFast || !canSendFast ) )
{
sendFastReject( msgs, req->index, req->offset, req->length );
}
else /* YAY */
{
if( peerIsFast && pieceIsFast )
reqListAppend( &msgs->peerAskedForFast, req );
else
reqListAppend( &msgs->peerAskedFor, req );
}
}
static int
messageLengthIsCorrect( const tr_peermsgs * msg, uint8_t id, uint32_t len )
{
switch( id )
{
case BT_CHOKE:
case BT_UNCHOKE:
case BT_INTERESTED:
case BT_NOT_INTERESTED:
case BT_HAVE_ALL:
case BT_HAVE_NONE:
return len==1;
case BT_HAVE:
case BT_SUGGEST:
case BT_ALLOWED_FAST:
return len==5;
case BT_BITFIELD:
return len == (msg->torrent->info.pieceCount+7u)/8u + 1u;
case BT_REQUEST:
case BT_CANCEL:
case BT_REJECT:
return len==13;
case BT_PIECE:
return len>9 && len<=16393;
case BT_PORT:
return len==3;
case BT_LTEP:
return len >= 2;
default:
return FALSE;
}
}
static int
clientGotBlock( tr_peermsgs * msgs, const uint8_t * block, const struct peer_request * req );
static void
clientGotBytes( tr_peermsgs * msgs, uint32_t byteCount )
{
const time_t now = time( NULL );
tr_torrent * tor = msgs->torrent;
tor->activityDate = tr_date( );
tor->downloadedCur += byteCount;
msgs->info->pieceDataActivityDate = now;
msgs->info->credit += (int)(byteCount * SWIFT_REPAYMENT_RATIO);
tr_rcTransferred( msgs->info->rcToClient, byteCount );
tr_rcTransferred( tor->download, byteCount );
tr_rcTransferred( tor->handle->download, byteCount );
tr_statsAddDownloaded( msgs->handle, byteCount );
firePieceData( msgs );
}
static int
readBtPiece( tr_peermsgs * msgs, struct evbuffer * inbuf, size_t inlen )
{
struct peer_request * req = &msgs->incoming.blockReq;
assert( EVBUFFER_LENGTH(inbuf) >= inlen );
dbgmsg( msgs, "In readBtPiece" );
if( !req->length )
{
if( inlen < 8 )
return READ_MORE;
tr_peerIoReadUint32( msgs->io, inbuf, &req->index );
tr_peerIoReadUint32( msgs->io, inbuf, &req->offset );
req->length = msgs->incoming.length - 9;
dbgmsg( msgs, "got incoming block header %u:%u->%u", req->index, req->offset, req->length );
return READ_AGAIN;
}
else
{
int err;
/* read in another chunk of data */
const size_t nLeft = req->length - EVBUFFER_LENGTH(msgs->incoming.block);
size_t n = MIN( nLeft, inlen );
uint8_t * buf = tr_new( uint8_t, n );
assert( EVBUFFER_LENGTH(inbuf) >= n );
tr_peerIoReadBytes( msgs->io, inbuf, buf, n );
evbuffer_add( msgs->incoming.block, buf, n );
clientGotBytes( msgs, n );
tr_free( buf );
dbgmsg( msgs, "got %d bytes for block %u:%u->%u ... %d remain",
(int)n, req->index, req->offset, req->length,
(int)( req->length - EVBUFFER_LENGTH(msgs->incoming.block) ) );
if( EVBUFFER_LENGTH(msgs->incoming.block) < req->length )
return READ_MORE;
/* we've got the whole block ... process it */
err = clientGotBlock( msgs, EVBUFFER_DATA(msgs->incoming.block), req );
/* cleanup */
evbuffer_drain( msgs->incoming.block, EVBUFFER_LENGTH(msgs->incoming.block) );
req->length = 0;
msgs->state = AWAITING_BT_LENGTH;
if( !err )
return READ_AGAIN;
else {
fireError( msgs, err );
return READ_DONE;
}
}
}
static int
readBtMessage( tr_peermsgs * msgs, struct evbuffer * inbuf, size_t inlen )
{
uint32_t ui32;
uint32_t msglen = msgs->incoming.length;
const uint8_t id = msgs->incoming.id;
const size_t startBufLen = EVBUFFER_LENGTH( inbuf );
--msglen; /* id length */
if( inlen < msglen )
return READ_MORE;
dbgmsg( msgs, "got BT id %d, len %d, buffer size is %d", (int)id, (int)msglen, (int)inlen );
if( !messageLengthIsCorrect( msgs, id, msglen+1 ) )
{
dbgmsg( msgs, "bad packet - BT message #%d with a length of %d", (int)id, (int)msglen );
fireError( msgs, TR_ERROR );
return READ_DONE;
}
switch( id )
{
case BT_CHOKE:
dbgmsg( msgs, "got Choke" );
msgs->info->clientIsChoked = 1;
cancelAllRequestsToPeer( msgs );
cancelAllRequestsToClientExceptFast( msgs );
break;
case BT_UNCHOKE:
dbgmsg( msgs, "got Unchoke" );
msgs->info->clientIsChoked = 0;
fireNeedReq( msgs );
break;
case BT_INTERESTED:
dbgmsg( msgs, "got Interested" );
msgs->info->peerIsInterested = 1;
tr_peerMsgsSetChoke( msgs, 0 );
break;
case BT_NOT_INTERESTED:
dbgmsg( msgs, "got Not Interested" );
msgs->info->peerIsInterested = 0;
break;
case BT_HAVE:
tr_peerIoReadUint32( msgs->io, inbuf, &ui32 );
dbgmsg( msgs, "got Have: %u", ui32 );
if( tr_bitfieldAdd( msgs->info->have, ui32 ) )
fireError( msgs, TR_ERROR_PEER_MESSAGE );
updatePeerProgress( msgs );
tr_rcTransferred( msgs->torrent->swarmSpeed, msgs->torrent->info.pieceSize );
break;
case BT_BITFIELD: {
dbgmsg( msgs, "got a bitfield" );
msgs->peerSentBitfield = 1;
tr_peerIoReadBytes( msgs->io, inbuf, msgs->info->have->bits, msglen );
updatePeerProgress( msgs );
maybeSendFastAllowedSet( msgs );
fireNeedReq( msgs );
break;
}
case BT_REQUEST: {
struct peer_request r;
tr_peerIoReadUint32( msgs->io, inbuf, &r.index );
tr_peerIoReadUint32( msgs->io, inbuf, &r.offset );
tr_peerIoReadUint32( msgs->io, inbuf, &r.length );
dbgmsg( msgs, "got Request: %u:%u->%u", r.index, r.offset, r.length );
peerMadeRequest( msgs, &r );
break;
}
case BT_CANCEL: {
struct peer_request r;
tr_peerIoReadUint32( msgs->io, inbuf, &r.index );
tr_peerIoReadUint32( msgs->io, inbuf, &r.offset );
tr_peerIoReadUint32( msgs->io, inbuf, &r.length );
dbgmsg( msgs, "got a Cancel %u:%u->%u", r.index, r.offset, r.length );
reqListRemove( &msgs->peerAskedForFast, &r );
reqListRemove( &msgs->peerAskedFor, &r );
break;
}
case BT_PIECE:
assert( 0 ); /* handled elsewhere! */
break;
case BT_PORT:
dbgmsg( msgs, "Got a BT_PORT" );
tr_peerIoReadUint16( msgs->io, inbuf, &msgs->info->port );
break;
case BT_SUGGEST: {
dbgmsg( msgs, "Got a BT_SUGGEST" );
tr_peerIoReadUint32( msgs->io, inbuf, &ui32 );
/* we don't do anything with this yet */
break;
}
case BT_HAVE_ALL:
dbgmsg( msgs, "Got a BT_HAVE_ALL" );
tr_bitfieldAddRange( msgs->info->have, 0, msgs->torrent->info.pieceCount );
updatePeerProgress( msgs );
maybeSendFastAllowedSet( msgs );
break;
case BT_HAVE_NONE:
dbgmsg( msgs, "Got a BT_HAVE_NONE" );
tr_bitfieldClear( msgs->info->have );
updatePeerProgress( msgs );
maybeSendFastAllowedSet( msgs );
break;
case BT_REJECT: {
struct peer_request r;
dbgmsg( msgs, "Got a BT_REJECT" );
tr_peerIoReadUint32( msgs->io, inbuf, &r.index );
tr_peerIoReadUint32( msgs->io, inbuf, &r.offset );
tr_peerIoReadUint32( msgs->io, inbuf, &r.length );
reqListRemove( &msgs->clientAskedFor, &r );
break;
}
case BT_ALLOWED_FAST: {
dbgmsg( msgs, "Got a BT_ALLOWED_FAST" );
tr_peerIoReadUint32( msgs->io, inbuf, &ui32 );
/* we don't do anything with this yet */
break;
}
case BT_LTEP:
dbgmsg( msgs, "Got a BT_LTEP" );
parseLtep( msgs, msglen, inbuf );
break;
default:
dbgmsg( msgs, "peer sent us an UNKNOWN: %d", (int)id );
tr_peerIoDrain( msgs->io, inbuf, msglen );
break;
}
assert( msglen + 1 == msgs->incoming.length );
assert( EVBUFFER_LENGTH(inbuf) == startBufLen - msglen );
msgs->state = AWAITING_BT_LENGTH;
return READ_AGAIN;
}
static void
peerGotBytes( tr_peermsgs * msgs, uint32_t byteCount )
{
const time_t now = time( NULL );
tr_torrent * tor = msgs->torrent;
tor->activityDate = tr_date( );
tor->uploadedCur += byteCount;
msgs->info->pieceDataActivityDate = now;
msgs->info->credit -= byteCount;
tr_rcTransferred( msgs->info->rcToPeer, byteCount );
tr_rcTransferred( tor->upload, byteCount );
tr_rcTransferred( tor->handle->upload, byteCount );
tr_statsAddUploaded( msgs->handle, byteCount );
firePieceData( msgs );
}
static size_t
getDownloadMax( const tr_peermsgs * msgs )
{
static const size_t maxval = ~0;
const tr_torrent * tor = msgs->torrent;
if( tor->downloadLimitMode == TR_SPEEDLIMIT_GLOBAL )
return tor->handle->useDownloadLimit
? tr_rcBytesLeft( tor->handle->download ) : maxval;
if( tor->downloadLimitMode == TR_SPEEDLIMIT_SINGLE )
return tr_rcBytesLeft( tor->download );
return maxval;
}
static void
decrementDownloadedCount( tr_peermsgs * msgs, uint32_t byteCount )
{
tr_torrent * tor = msgs->torrent;
tor->downloadedCur -= MIN( tor->downloadedCur, byteCount );
}
static void
reassignBytesToCorrupt( tr_peermsgs * msgs, uint32_t byteCount )
{
tr_torrent * tor = msgs->torrent;
tor->corruptCur += byteCount;
decrementDownloadedCount( msgs, byteCount );
}
static void
gotBadPiece( tr_peermsgs * msgs, tr_piece_index_t pieceIndex )
{
const uint32_t byteCount =
tr_torPieceCountBytes( msgs->torrent, pieceIndex );
reassignBytesToCorrupt( msgs, byteCount );
}
static void
clientGotUnwantedBlock( tr_peermsgs * msgs, const struct peer_request * req )
{
decrementDownloadedCount( msgs, req->length );
}
static void
addPeerToBlamefield( tr_peermsgs * msgs, uint32_t index )
{
if( !msgs->info->blame )
msgs->info->blame = tr_bitfieldNew( msgs->torrent->info.pieceCount );
tr_bitfieldAdd( msgs->info->blame, index );
}
static tr_errno
clientGotBlock( tr_peermsgs * msgs,
const uint8_t * data,
const struct peer_request * req )
{
int err;
tr_torrent * tor = msgs->torrent;
const tr_block_index_t block = _tr_block( tor, req->index, req->offset );
assert( msgs != NULL );
assert( req != NULL );
if( req->length != tr_torBlockCountBytes( msgs->torrent, block ) )
{
dbgmsg( msgs, "wrong block size -- expected %u, got %d",
tr_torBlockCountBytes( msgs->torrent, block ), req->length );
return TR_ERROR;
}
/* save the block */
dbgmsg( msgs, "got block %u:%u->%u", req->index, req->offset, req->length );
/**
*** Remove the block from our `we asked for this' list
**/
if( reqListRemove( &msgs->clientAskedFor, req ) )
{
clientGotUnwantedBlock( msgs, req );
dbgmsg( msgs, "we didn't ask for this message..." );
return 0;
}
dbgmsg( msgs, "peer has %d more blocks we've asked for",
msgs->clientAskedFor.count );
/**
*** Error checks
**/
if( tr_cpBlockIsComplete( tor->completion, block ) ) {
dbgmsg( msgs, "we have this block already..." );
clientGotUnwantedBlock( msgs, req );
return 0;
}
/**
*** Save the block
**/
msgs->info->peerSentPieceDataAt = time( NULL );
if(( err = tr_ioWrite( tor, req->index, req->offset, req->length, data )))
return err;
tr_cpBlockAdd( tor->completion, block );
addPeerToBlamefield( msgs, req->index );
fireGotBlock( msgs, req );
/**
*** Handle if this was the last block in the piece
**/
if( tr_cpPieceIsComplete( tor->completion, req->index ) )
{
const tr_errno err = tr_ioTestPiece( tor, req->index );
if( err )
tr_torerr( tor, _( "Piece %lu, which was just downloaded, failed its checksum test: %s" ),
(unsigned long)req->index,
tr_errorString( err ) );
tr_torrentSetHasPiece( tor, req->index, !err );
tr_torrentSetPieceChecked( tor, req->index, TRUE );
tr_peerMgrSetBlame( tor->handle->peerMgr, tor->info.hash, req->index, !err );
if( !err )
fireClientHave( msgs, req->index );
else
gotBadPiece( msgs, req->index );
}
return 0;
}
static void
didWrite( struct bufferevent * evin UNUSED, void * vmsgs )
{
pulse( vmsgs );
}
static ReadState
canRead( struct bufferevent * evin, void * vmsgs )
{
ReadState ret;
tr_peermsgs * msgs = vmsgs;
struct evbuffer * in = EVBUFFER_INPUT ( evin );
const size_t inlen = EVBUFFER_LENGTH( in );
if( !inlen )
{
ret = READ_DONE;
}
else if( msgs->state == AWAITING_BT_PIECE )
{
const size_t downloadMax = getDownloadMax( msgs );
const size_t n = MIN( inlen, downloadMax );
ret = n ? readBtPiece( msgs, in, n ) : READ_DONE;
}
else switch( msgs->state )
{
case AWAITING_BT_LENGTH: ret = readBtLength ( msgs, in, inlen ); break;
case AWAITING_BT_ID: ret = readBtId ( msgs, in, inlen ); break;
case AWAITING_BT_MESSAGE: ret = readBtMessage( msgs, in, inlen ); break;
default: assert( 0 );
}
return ret;
}
static void
sendKeepalive( tr_peermsgs * msgs )
{
dbgmsg( msgs, "sending a keepalive message" );
tr_peerIoWriteUint32( msgs->io, msgs->outMessages, 0 );
}
/**
***
**/
static int
isSwiftEnabled( const tr_peermsgs * msgs )
{
/* rationale: SWIFT is good for getting rid of deadbeats, but most
* private trackers have ratios where you _want_ to feed deadbeats
* as much as possible. So we disable SWIFT on private torrents */
return SWIFT_ENABLED
&& !tr_torrentIsSeed( msgs->torrent )
&& !tr_torrentIsPrivate( msgs->torrent );
}
static size_t
getUploadMax( const tr_peermsgs * msgs )
{
static const size_t maxval = ~0;
const tr_torrent * tor = msgs->torrent;
const int useSwift = isSwiftEnabled( msgs );
const size_t swiftLeft = msgs->info->credit;
int speedLeft;
int bufLeft;
size_t ret;
if( tor->uploadLimitMode == TR_SPEEDLIMIT_GLOBAL )
speedLeft = tor->handle->useUploadLimit ? tr_rcBytesLeft( tor->handle->upload ) : maxval;
else if( tor->uploadLimitMode == TR_SPEEDLIMIT_SINGLE )
speedLeft = tr_rcBytesLeft( tor->upload );
else
speedLeft = INT_MAX;
/* this basically says the outbuf shouldn't have more than one block
* queued up in it... blocksize, +13 for the size of the BT protocol's
* block message overhead */
bufLeft = tor->blockSize + 13 - tr_peerIoWriteBytesWaiting( msgs->io );
ret = MIN( speedLeft, bufLeft );
if( useSwift)
ret = MIN( ret, swiftLeft );
return ret;
}
static int
ratePulse( void * vmsgs )
{
tr_peermsgs * msgs = (tr_peermsgs *) vmsgs;
msgs->info->rateToClient = tr_rcRate( msgs->info->rcToClient );
msgs->info->rateToPeer = tr_rcRate( msgs->info->rcToPeer );
msgs->maxActiveRequests = MIN( 4 + (int)(msgs->info->rateToClient/4), MAX_QUEUE_SIZE );
msgs->minActiveRequests = msgs->maxActiveRequests / 3;
return TRUE;
}
static tr_errno
popNextRequest( tr_peermsgs * msgs, struct peer_request * setme )
{
if( !reqListPop( &msgs->peerAskedForFast, setme ) )
return 0;
if( !reqListPop( &msgs->peerAskedFor, setme ) )
return 0;
return TR_ERROR;
}
static int
pulse( void * vmsgs )
{
const time_t now = time( NULL );
tr_peermsgs * msgs = vmsgs;
tr_peerIoTryRead( msgs->io );
pumpRequestQueue( msgs );
expireOldRequests( msgs );
if( msgs->sendingBlock )
{
const size_t uploadMax = getUploadMax( msgs );
size_t len = EVBUFFER_LENGTH( msgs->outBlock );
const size_t outlen = MIN( len, uploadMax );
assert( len );
if( outlen )
{
tr_peerIoWrite( msgs->io, EVBUFFER_DATA( msgs->outBlock ), outlen );
evbuffer_drain( msgs->outBlock, outlen );
peerGotBytes( msgs, outlen );
len -= outlen;
msgs->clientSentAnythingAt = now;
msgs->sendingBlock = len!=0;
dbgmsg( msgs, "wrote %d bytes; %d left in block", (int)outlen, (int)len );
}
else dbgmsg( msgs, "stalled writing block... uploadMax %lu, outlen %lu", uploadMax, outlen );
}
if( !msgs->sendingBlock )
{
struct peer_request req;
if(( EVBUFFER_LENGTH( msgs->outMessages ) ))
{
dbgmsg( msgs, "flushing outMessages..." );
tr_peerIoWriteBuf( msgs->io, msgs->outMessages );
msgs->clientSentAnythingAt = now;
}
else if( !EVBUFFER_LENGTH( msgs->outBlock )
&& !popNextRequest( msgs, &req )
&& requestIsValid( msgs, &req )
&& tr_cpPieceIsComplete( msgs->torrent->completion, req.index ) )
{
uint8_t * buf = tr_new( uint8_t, req.length );
if( !tr_ioRead( msgs->torrent, req.index, req.offset, req.length, buf ) )
{
tr_peerIo * io = msgs->io;
struct evbuffer * out = msgs->outBlock;
dbgmsg( msgs, "sending block %u:%u->%u", req.index, req.offset, req.length );
tr_peerIoWriteUint32( io, out, sizeof(uint8_t) + 2*sizeof(uint32_t) + req.length );
tr_peerIoWriteUint8 ( io, out, BT_PIECE );
tr_peerIoWriteUint32( io, out, req.index );
tr_peerIoWriteUint32( io, out, req.offset );
tr_peerIoWriteBytes ( io, out, buf, req.length );
msgs->sendingBlock = 1;
}
tr_free( buf );
}
else if( ( now - msgs->clientSentAnythingAt ) > KEEPALIVE_INTERVAL_SECS )
{
sendKeepalive( msgs );
}
}
return TRUE; /* loop forever */
}
static void
gotError( struct bufferevent * evbuf UNUSED, short what, void * vmsgs )
{
if( what & EVBUFFER_TIMEOUT )
dbgmsg( vmsgs, "libevent got a timeout, what=%hd", what );
if( what & ( EVBUFFER_EOF | EVBUFFER_ERROR ) )
dbgmsg( vmsgs, "libevent got an error! what=%hd, errno=%d (%s)",
what, errno, tr_strerror(errno) );
fireError( vmsgs, TR_ERROR );
}
static void
sendBitfield( tr_peermsgs * msgs )
{
const tr_bitfield * bitfield = tr_cpPieceBitfield( msgs->torrent->completion );
struct evbuffer * out = msgs->outMessages;
dbgmsg( msgs, "sending peer a bitfield message" );
tr_peerIoWriteUint32( msgs->io, out, sizeof(uint8_t) + bitfield->len );
tr_peerIoWriteUint8 ( msgs->io, out, BT_BITFIELD );
tr_peerIoWriteBytes ( msgs->io, out, bitfield->bits, bitfield->len );
}
/**
***
**/
/* some peers give us error messages if we send
more than this many peers in a single pex message
http://wiki.theory.org/BitTorrentPeerExchangeConventions */
#define MAX_PEX_ADDED 50
#define MAX_PEX_DROPPED 50
typedef struct
{
tr_pex * added;
tr_pex * dropped;
tr_pex * elements;
int addedCount;
int droppedCount;
int elementCount;
}
PexDiffs;
static void
pexAddedCb( void * vpex, void * userData )
{
PexDiffs * diffs = userData;
tr_pex * pex = vpex;
if( diffs->addedCount < MAX_PEX_ADDED )
{
diffs->added[diffs->addedCount++] = *pex;
diffs->elements[diffs->elementCount++] = *pex;
}
}
static void
pexDroppedCb( void * vpex, void * userData )
{
PexDiffs * diffs = userData;
tr_pex * pex = vpex;
if( diffs->droppedCount < MAX_PEX_DROPPED )
{
diffs->dropped[diffs->droppedCount++] = *pex;
}
}
static void
pexElementCb( void * vpex, void * userData )
{
PexDiffs * diffs = userData;
tr_pex * pex = vpex;
diffs->elements[diffs->elementCount++] = *pex;
}
static void
sendPex( tr_peermsgs * msgs )
{
if( msgs->peerSupportsPex && tr_torrentAllowsPex( msgs->torrent ) )
{
int i;
tr_pex * newPex = NULL;
const int newCount = tr_peerMgrGetPeers( msgs->handle->peerMgr, msgs->torrent->info.hash, &newPex );
PexDiffs diffs;
tr_benc val, *added, *dropped;
uint8_t *tmp, *walk;
char * benc;
int bencLen;
/* build the diffs */
diffs.added = tr_new( tr_pex, newCount );
diffs.addedCount = 0;
diffs.dropped = tr_new( tr_pex, msgs->pexCount );
diffs.droppedCount = 0;
diffs.elements = tr_new( tr_pex, newCount + msgs->pexCount );
diffs.elementCount = 0;
tr_set_compare( msgs->pex, msgs->pexCount,
newPex, newCount,
tr_pexCompare, sizeof(tr_pex),
pexDroppedCb, pexAddedCb, pexElementCb, &diffs );
dbgmsg( msgs, "pex: old peer count %d, new peer count %d, added %d, removed %d", msgs->pexCount, newCount, diffs.addedCount, diffs.droppedCount );
/* update peer */
tr_free( msgs->pex );
msgs->pex = diffs.elements;
msgs->pexCount = diffs.elementCount;
/* build the pex payload */
tr_bencInitDict( &val, 3 );
/* "added" */
added = tr_bencDictAdd( &val, "added" );
tmp = walk = tr_new( uint8_t, diffs.addedCount * 6 );
for( i=0; i<diffs.addedCount; ++i ) {
memcpy( walk, &diffs.added[i].in_addr, 4 ); walk += 4;
memcpy( walk, &diffs.added[i].port, 2 ); walk += 2;
}
assert( ( walk - tmp ) == diffs.addedCount * 6 );
tr_bencInitStr( added, tmp, walk-tmp, FALSE );
/* "added.f" */
tmp = walk = tr_new( uint8_t, diffs.addedCount );
for( i=0; i<diffs.addedCount; ++i )
*walk++ = diffs.added[i].flags;
assert( ( walk - tmp ) == diffs.addedCount );
tr_bencDictAddRaw( &val, "added.f", tmp, walk-tmp );
/* "dropped" */
dropped = tr_bencDictAdd( &val, "dropped" );
tmp = walk = tr_new( uint8_t, diffs.droppedCount * 6 );
for( i=0; i<diffs.droppedCount; ++i ) {
memcpy( walk, &diffs.dropped[i].in_addr, 4 ); walk += 4;
memcpy( walk, &diffs.dropped[i].port, 2 ); walk += 2;
}
assert( ( walk - tmp ) == diffs.droppedCount * 6 );
tr_bencInitStr( dropped, tmp, walk-tmp, FALSE );
/* write the pex message */
benc = tr_bencSave( &val, &bencLen );
tr_peerIoWriteUint32( msgs->io, msgs->outMessages, 2*sizeof(uint8_t) + bencLen );
tr_peerIoWriteUint8 ( msgs->io, msgs->outMessages, BT_LTEP );
tr_peerIoWriteUint8 ( msgs->io, msgs->outMessages, msgs->ut_pex_id );
tr_peerIoWriteBytes ( msgs->io, msgs->outMessages, benc, bencLen );
/* cleanup */
tr_free( benc );
tr_bencFree( &val );
tr_free( diffs.added );
tr_free( diffs.dropped );
tr_free( newPex );
msgs->clientSentPexAt = time( NULL );
}
}
static int
pexPulse( void * vpeer )
{
sendPex( vpeer );
return TRUE;
}
/**
***
**/
tr_peermsgs*
tr_peerMsgsNew( struct tr_torrent * torrent,
struct tr_peer * info,
tr_delivery_func func,
void * userData,
tr_publisher_tag * setme )
{
tr_peermsgs * m;
assert( info != NULL );
assert( info->io != NULL );
m = tr_new0( tr_peermsgs, 1 );
m->publisher = tr_publisherNew( );
m->info = info;
m->handle = torrent->handle;
m->torrent = torrent;
m->io = info->io;
m->info->clientIsChoked = 1;
m->info->peerIsChoked = 1;
m->info->clientIsInterested = 0;
m->info->peerIsInterested = 0;
m->info->have = tr_bitfieldNew( torrent->info.pieceCount );
m->state = AWAITING_BT_LENGTH;
m->pulseTimer = tr_timerNew( m->handle, pulse, m, PEER_PULSE_INTERVAL );
m->rateTimer = tr_timerNew( m->handle, ratePulse, m, RATE_PULSE_INTERVAL );
m->pexTimer = tr_timerNew( m->handle, pexPulse, m, PEX_INTERVAL );
m->outMessages = evbuffer_new( );
m->incoming.block = evbuffer_new( );
m->outBlock = evbuffer_new( );
m->peerAllowedPieces = NULL;
m->peerAskedFor = REQUEST_LIST_INIT;
m->peerAskedForFast = REQUEST_LIST_INIT;
m->clientAskedFor = REQUEST_LIST_INIT;
m->clientWillAskFor = REQUEST_LIST_INIT;
*setme = tr_publisherSubscribe( m->publisher, func, userData );
if ( tr_peerIoSupportsLTEP( m->io ) )
sendLtepHandshake( m );
sendBitfield( m );
tr_peerIoSetTimeoutSecs( m->io, 150 ); /* timeout after N seconds of inactivity */
tr_peerIoSetIOFuncs( m->io, canRead, didWrite, gotError, m );
ratePulse( m );
return m;
}
void
tr_peerMsgsFree( tr_peermsgs* msgs )
{
if( msgs != NULL )
{
tr_timerFree( &msgs->pulseTimer );
tr_timerFree( &msgs->rateTimer );
tr_timerFree( &msgs->pexTimer );
tr_publisherFree( &msgs->publisher );
reqListClear( &msgs->clientWillAskFor );
reqListClear( &msgs->clientAskedFor );
reqListClear( &msgs->peerAskedForFast );
reqListClear( &msgs->peerAskedFor );
tr_bitfieldFree( msgs->peerAllowedPieces );
evbuffer_free( msgs->incoming.block );
evbuffer_free( msgs->outMessages );
evbuffer_free( msgs->outBlock );
tr_free( msgs->pex );
memset( msgs, ~0, sizeof( tr_peermsgs ) );
tr_free( msgs );
}
}
tr_publisher_tag
tr_peerMsgsSubscribe( tr_peermsgs * peer,
tr_delivery_func func,
void * userData )
{
return tr_publisherSubscribe( peer->publisher, func, userData );
}
void
tr_peerMsgsUnsubscribe( tr_peermsgs * peer,
tr_publisher_tag tag )
{
tr_publisherUnsubscribe( peer->publisher, tag );
}
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