transmission/libtransmission/peer-io.c

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/*
2008-01-01 17:20:20 +00:00
* 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.
*
* $Id$
*/
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#include <assert.h>
#include <limits.h> /* INT_MAX */
#include <string.h>
#include <stdio.h>
#include <unistd.h>
#ifdef WIN32
#include <winsock2.h>
#else
#include <netinet/in.h> /* struct in_addr */
#include <arpa/inet.h> /* inet_ntoa */
#endif
#include <event.h>
#include "transmission.h"
#include "bandwidth.h"
#include "crypto.h"
#include "iobuf.h"
#include "list.h"
#include "net.h"
#include "peer-io.h"
#include "trevent.h"
#include "utils.h"
#define MAGIC_NUMBER 206745
#define IO_TIMEOUT_SECS 8
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static size_t
getPacketOverhead( size_t d )
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{
/**
* http://sd.wareonearth.com/~phil/net/overhead/
*
* TCP over Ethernet:
* Assuming no header compression (e.g. not PPP)
* Add 20 IPv4 header or 40 IPv6 header (no options)
* Add 20 TCP header
* Add 12 bytes optional TCP timestamps
* Max TCP Payload data rates over ethernet are thus:
* (1500-40)/(38+1500) = 94.9285 % IPv4, minimal headers
* (1500-52)/(38+1500) = 94.1482 % IPv4, TCP timestamps
* (1500-52)/(42+1500) = 93.9040 % 802.1q, IPv4, TCP timestamps
* (1500-60)/(38+1500) = 93.6281 % IPv6, minimal headers
* (1500-72)/(38+1500) = 92.8479 % IPv6, TCP timestamps
* (1500-72)/(42+1500) = 92.6070 % 802.1q, IPv6, ICP timestamps
*/
static const double assumed_payload_data_rate = 94.0;
return (size_t)( d * ( 100.0 / assumed_payload_data_rate ) - d );
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}
/**
***
**/
#define dbgmsg( io, ... ) \
do { \
if( tr_deepLoggingIsActive( ) ) \
tr_deepLog( __FILE__, __LINE__, tr_peerIoGetAddrStr( io ), __VA_ARGS__ ); \
} while( 0 )
struct tr_datatype
{
unsigned int isPieceData : 1;
size_t length;
};
struct tr_peerIo
{
unsigned int isEncrypted : 1;
unsigned int isIncoming : 1;
unsigned int peerIdIsSet : 1;
unsigned int extendedProtocolSupported : 1;
unsigned int fastPeersSupported : 1;
int magicNumber;
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uint8_t encryptionMode;
uint8_t timeout;
uint16_t port;
int socket;
uint8_t peerId[20];
time_t timeCreated;
tr_session * session;
struct in_addr in_addr;
struct tr_iobuf * iobuf;
tr_list * output_datatypes; /* struct tr_datatype */
tr_can_read_cb canRead;
tr_did_write_cb didWrite;
tr_net_error_cb gotError;
void * userData;
size_t bufferSize[2];
tr_bandwidth * bandwidth;
tr_crypto * crypto;
};
/***
****
***/
static void
didWriteWrapper( struct tr_iobuf * iobuf,
size_t bytes_transferred,
void * vio )
{
tr_peerIo * io = vio;
while( bytes_transferred )
{
struct tr_datatype * next = io->output_datatypes->data;
const size_t payload = MIN( next->length, bytes_transferred );
const size_t overhead = getPacketOverhead( payload );
tr_bandwidthUsed( io->bandwidth, TR_UP, payload, next->isPieceData );
if( overhead > 0 )
tr_bandwidthUsed( io->bandwidth, TR_UP, overhead, FALSE );
if( io->didWrite )
io->didWrite( io, payload, next->isPieceData, io->userData );
bytes_transferred -= payload;
next->length -= payload;
if( !next->length )
tr_free( tr_list_pop_front( &io->output_datatypes ) );
}
if( EVBUFFER_LENGTH( tr_iobuf_output( iobuf ) ) )
tr_iobuf_enable( io->iobuf, EV_WRITE );
}
static void
canReadWrapper( struct tr_iobuf * iobuf,
size_t bytes_transferred UNUSED,
void * vio )
{
int done = 0;
int err = 0;
tr_peerIo * io = vio;
tr_session * session = io->session;
dbgmsg( io, "canRead" );
/* try to consume the input buffer */
if( io->canRead )
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{
tr_globalLock( session );
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while( !done && !err )
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{
size_t piece = 0;
const size_t oldLen = EVBUFFER_LENGTH( tr_iobuf_input( iobuf ) );
const int ret = io->canRead( iobuf, io->userData, &piece );
if( ret != READ_ERR )
{
const size_t used = oldLen - EVBUFFER_LENGTH( tr_iobuf_input( iobuf ) );
if( piece )
tr_bandwidthUsed( io->bandwidth, TR_DOWN, piece, TRUE );
if( used != piece )
tr_bandwidthUsed( io->bandwidth, TR_DOWN, used - piece, FALSE );
}
switch( ret )
{
case READ_NOW:
if( EVBUFFER_LENGTH( tr_iobuf_input( iobuf )))
continue;
done = 1;
break;
case READ_LATER:
done = 1;
break;
case READ_ERR:
err = 1;
break;
}
}
tr_globalUnlock( session );
}
}
static void
gotErrorWrapper( struct tr_iobuf * iobuf,
short what,
void * userData )
{
tr_peerIo * c = userData;
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if( c->gotError )
c->gotError( iobuf, what, c->userData );
}
/**
***
**/
static void
bufevNew( tr_peerIo * io )
{
io->iobuf = tr_iobuf_new( io->session,
io->bandwidth,
io->socket,
EV_READ | EV_WRITE,
canReadWrapper,
didWriteWrapper,
gotErrorWrapper,
io );
tr_iobuf_settimeout( io->iobuf, io->timeout, io->timeout );
}
static int
isPeerIo( const tr_peerIo * io )
{
return ( io != NULL ) && ( io->magicNumber == MAGIC_NUMBER );
}
static tr_peerIo*
tr_peerIoNew( tr_session * session,
const struct in_addr * in_addr,
uint16_t port,
const uint8_t * torrentHash,
int isIncoming,
int socket )
{
tr_peerIo * io;
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if( socket >= 0 )
tr_netSetTOS( socket, session->peerSocketTOS );
io = tr_new0( tr_peerIo, 1 );
io->magicNumber = MAGIC_NUMBER;
io->crypto = tr_cryptoNew( torrentHash, isIncoming );
io->session = session;
io->in_addr = *in_addr;
io->port = port;
io->socket = socket;
io->isIncoming = isIncoming != 0;
io->timeout = IO_TIMEOUT_SECS;
io->timeCreated = time( NULL );
bufevNew( io );
tr_peerIoSetBandwidth( io, session->bandwidth );
return io;
}
tr_peerIo*
tr_peerIoNewIncoming( tr_session * session,
const struct in_addr * in_addr,
uint16_t port,
int socket )
{
assert( session );
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assert( in_addr );
assert( socket >= 0 );
return tr_peerIoNew( session, in_addr, port,
NULL, 1,
socket );
}
tr_peerIo*
tr_peerIoNewOutgoing( tr_session * session,
const struct in_addr * in_addr,
int port,
const uint8_t * torrentHash )
{
int socket;
assert( session );
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assert( in_addr );
assert( port >= 0 );
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assert( torrentHash );
socket = tr_netOpenTCP( session, in_addr, port );
return socket < 0
? NULL
: tr_peerIoNew( session, in_addr, port, torrentHash, 0, socket );
}
static void
io_dtor( void * vio )
{
tr_peerIo * io = vio;
tr_peerIoSetBandwidth( io, NULL );
tr_iobuf_free( io->iobuf );
tr_netClose( io->socket );
tr_cryptoFree( io->crypto );
tr_list_free( &io->output_datatypes, tr_free );
io->magicNumber = 0xDEAD;
tr_free( io );
}
void
tr_peerIoFree( tr_peerIo * io )
{
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if( io )
{
io->canRead = NULL;
io->didWrite = NULL;
io->gotError = NULL;
tr_runInEventThread( io->session, io_dtor, io );
}
}
tr_session*
tr_peerIoGetSession( tr_peerIo * io )
{
assert( isPeerIo( io ) );
assert( io->session );
return io->session;
}
const struct in_addr*
tr_peerIoGetAddress( const tr_peerIo * io,
uint16_t * port )
{
assert( isPeerIo( io ) );
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if( port )
*port = io->port;
return &io->in_addr;
}
const char*
tr_peerIoAddrStr( const struct in_addr * addr,
uint16_t port )
{
static char buf[512];
tr_snprintf( buf, sizeof( buf ), "%s:%u", inet_ntoa( *addr ),
ntohs( port ) );
return buf;
}
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const char*
tr_peerIoGetAddrStr( const tr_peerIo * io )
{
return tr_peerIoAddrStr( &io->in_addr, io->port );
}
static void
tr_peerIoTryRead( tr_peerIo * io )
{
if( EVBUFFER_LENGTH( tr_iobuf_input( io->iobuf )))
(*canReadWrapper)( io->iobuf, ~0, io );
}
void
tr_peerIoSetIOFuncs( tr_peerIo * io,
tr_can_read_cb readcb,
tr_did_write_cb writecb,
tr_net_error_cb errcb,
void * userData )
{
io->canRead = readcb;
io->didWrite = writecb;
io->gotError = errcb;
io->userData = userData;
tr_peerIoTryRead( io );
}
int
tr_peerIoIsIncoming( const tr_peerIo * c )
{
return c->isIncoming ? 1 : 0;
}
int
tr_peerIoReconnect( tr_peerIo * io )
{
assert( !tr_peerIoIsIncoming( io ) );
if( io->socket >= 0 )
tr_netClose( io->socket );
io->socket = tr_netOpenTCP( io->session, &io->in_addr, io->port );
if( io->socket >= 0 )
{
tr_bandwidth * bandwidth = io->bandwidth;
tr_peerIoSetBandwidth( io, NULL );
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tr_netSetTOS( io->socket, io->session->peerSocketTOS );
tr_iobuf_free( io->iobuf );
bufevNew( io );
tr_peerIoSetBandwidth( io, bandwidth );
return 0;
}
return -1;
}
void
tr_peerIoSetTimeoutSecs( tr_peerIo * io,
int secs )
{
io->timeout = secs;
tr_iobuf_settimeout( io->iobuf, io->timeout, io->timeout );
tr_iobuf_enable( io->iobuf, EV_READ | EV_WRITE );
}
/**
***
**/
void
tr_peerIoSetTorrentHash( tr_peerIo * io,
const uint8_t * hash )
{
assert( isPeerIo( io ) );
tr_cryptoSetTorrentHash( io->crypto, hash );
}
const uint8_t*
tr_peerIoGetTorrentHash( tr_peerIo * io )
{
assert( isPeerIo( io ) );
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assert( io->crypto );
return tr_cryptoGetTorrentHash( io->crypto );
}
int
tr_peerIoHasTorrentHash( const tr_peerIo * io )
{
assert( isPeerIo( io ) );
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assert( io->crypto );
return tr_cryptoHasTorrentHash( io->crypto );
}
/**
***
**/
void
tr_peerIoSetPeersId( tr_peerIo * io,
const uint8_t * peer_id )
{
assert( isPeerIo( io ) );
if( ( io->peerIdIsSet = peer_id != NULL ) )
memcpy( io->peerId, peer_id, 20 );
else
memset( io->peerId, 0, 20 );
}
const uint8_t*
tr_peerIoGetPeersId( const tr_peerIo * io )
{
assert( isPeerIo( io ) );
assert( io->peerIdIsSet );
return io->peerId;
}
/**
***
**/
void
tr_peerIoEnableLTEP( tr_peerIo * io,
int flag )
{
assert( isPeerIo( io ) );
assert( flag == 0 || flag == 1 );
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io->extendedProtocolSupported = flag;
}
void
tr_peerIoEnableFEXT( tr_peerIo * io,
int flag )
{
assert( isPeerIo( io ) );
assert( flag == 0 || flag == 1 );
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io->fastPeersSupported = flag;
}
int
tr_peerIoSupportsLTEP( const tr_peerIo * io )
{
assert( isPeerIo( io ) );
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return io->extendedProtocolSupported;
}
int
tr_peerIoSupportsFEXT( const tr_peerIo * io )
{
assert( isPeerIo( io ) );
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return io->fastPeersSupported;
}
/**
***
**/
static size_t
getDesiredOutputBufferSize( const tr_peerIo * io )
{
/* this is all kind of arbitrary, but what seems to work well is
* being large enough to hold the next 15 seconds' worth of input,
* or two and a half blocks, whichever is bigger.
* It's okay to tweak this as needed */
const double maxBlockSize = 16 * 1024; /* 16 KiB is from BT spec */
const double currentSpeed = tr_bandwidthGetPieceSpeed( io->bandwidth, TR_UP );
const double period = 20; /* arbitrary */
return MAX( maxBlockSize*2.5, currentSpeed*1024*period );
}
size_t
tr_peerIoGetWriteBufferSpace( const tr_peerIo * io )
{
const size_t desiredLen = getDesiredOutputBufferSize( io );
const size_t currentLen = EVBUFFER_LENGTH( tr_iobuf_output( io->iobuf ) );
size_t freeSpace = 0;
if( desiredLen > currentLen )
freeSpace = desiredLen - currentLen;
return freeSpace;
}
void
tr_peerIoSetBandwidth( tr_peerIo * io,
tr_bandwidth * bandwidth )
{
assert( isPeerIo( io ) );
if( io->bandwidth )
tr_bandwidthRemoveBuffer( io->bandwidth, io->iobuf );
io->bandwidth = bandwidth;
tr_iobuf_set_bandwidth( io->iobuf, bandwidth );
if( io->bandwidth )
tr_bandwidthAddBuffer( io->bandwidth, io->iobuf );
tr_iobuf_enable( io->iobuf, EV_READ | EV_WRITE );
}
/**
***
**/
tr_crypto*
tr_peerIoGetCrypto( tr_peerIo * c )
{
return c->crypto;
}
void
tr_peerIoSetEncryption( tr_peerIo * io,
int encryptionMode )
{
assert( isPeerIo( io ) );
assert( encryptionMode == PEER_ENCRYPTION_NONE
|| encryptionMode == PEER_ENCRYPTION_RC4 );
io->encryptionMode = encryptionMode;
}
int
tr_peerIoIsEncrypted( const tr_peerIo * io )
{
return io != NULL && io->encryptionMode == PEER_ENCRYPTION_RC4;
}
/**
***
**/
void
tr_peerIoWrite( tr_peerIo * io,
const void * writeme,
size_t writemeLen,
int isPieceData )
{
struct tr_datatype * datatype;
assert( tr_amInEventThread( io->session ) );
dbgmsg( io, "adding %zu bytes into io->output", writemeLen );
datatype = tr_new( struct tr_datatype, 1 );
datatype->isPieceData = isPieceData != 0;
datatype->length = writemeLen;
tr_list_append( &io->output_datatypes, datatype );
evbuffer_add( tr_iobuf_output( io->iobuf ), writeme, writemeLen );
tr_iobuf_enable( io->iobuf, EV_WRITE );
}
void
tr_peerIoWriteBuf( tr_peerIo * io,
struct evbuffer * buf,
int isPieceData )
{
const size_t n = EVBUFFER_LENGTH( buf );
tr_peerIoWrite( io, EVBUFFER_DATA( buf ), n, isPieceData );
evbuffer_drain( buf, n );
}
/**
***
**/
void
tr_peerIoWriteBytes( tr_peerIo * io,
struct evbuffer * outbuf,
const void * bytes,
size_t byteCount )
{
uint8_t * tmp;
switch( io->encryptionMode )
{
case PEER_ENCRYPTION_NONE:
evbuffer_add( outbuf, bytes, byteCount );
break;
case PEER_ENCRYPTION_RC4:
tmp = tr_new( uint8_t, byteCount );
tr_cryptoEncrypt( io->crypto, byteCount, bytes, tmp );
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evbuffer_add( outbuf, tmp, byteCount );
tr_free( tmp );
break;
default:
assert( 0 );
}
}
void
tr_peerIoWriteUint8( tr_peerIo * io,
struct evbuffer * outbuf,
uint8_t writeme )
{
tr_peerIoWriteBytes( io, outbuf, &writeme, sizeof( uint8_t ) );
}
void
tr_peerIoWriteUint16( tr_peerIo * io,
struct evbuffer * outbuf,
uint16_t writeme )
{
uint16_t tmp = htons( writeme );
tr_peerIoWriteBytes( io, outbuf, &tmp, sizeof( uint16_t ) );
}
void
tr_peerIoWriteUint32( tr_peerIo * io,
struct evbuffer * outbuf,
uint32_t writeme )
{
uint32_t tmp = htonl( writeme );
tr_peerIoWriteBytes( io, outbuf, &tmp, sizeof( uint32_t ) );
}
/***
****
***/
void
tr_peerIoReadBytes( tr_peerIo * io,
struct evbuffer * inbuf,
void * bytes,
size_t byteCount )
{
assert( EVBUFFER_LENGTH( inbuf ) >= byteCount );
switch( io->encryptionMode )
{
case PEER_ENCRYPTION_NONE:
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evbuffer_remove( inbuf, bytes, byteCount );
break;
case PEER_ENCRYPTION_RC4:
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evbuffer_remove( inbuf, bytes, byteCount );
tr_cryptoDecrypt( io->crypto, byteCount, bytes, bytes );
break;
default:
assert( 0 );
}
}
void
tr_peerIoReadUint8( tr_peerIo * io,
struct evbuffer * inbuf,
uint8_t * setme )
{
tr_peerIoReadBytes( io, inbuf, setme, sizeof( uint8_t ) );
}
void
tr_peerIoReadUint16( tr_peerIo * io,
struct evbuffer * inbuf,
uint16_t * setme )
{
uint16_t tmp;
tr_peerIoReadBytes( io, inbuf, &tmp, sizeof( uint16_t ) );
*setme = ntohs( tmp );
}
void
tr_peerIoReadUint32( tr_peerIo * io,
struct evbuffer * inbuf,
uint32_t * setme )
{
uint32_t tmp;
tr_peerIoReadBytes( io, inbuf, &tmp, sizeof( uint32_t ) );
*setme = ntohl( tmp );
}
void
tr_peerIoDrain( tr_peerIo * io,
struct evbuffer * inbuf,
size_t byteCount )
{
uint8_t * tmp = tr_new( uint8_t, byteCount );
tr_peerIoReadBytes( io, inbuf, tmp, byteCount );
tr_free( tmp );
}
int
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tr_peerIoGetAge( const tr_peerIo * io )
{
return time( NULL ) - io->timeCreated;
}