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transmission/libtransmission/peer-io.c

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/*
* This file Copyright (C) Mnemosyne LLC
*
* 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 <string.h>
#include <stdio.h>
#include <unistd.h>
#ifdef WIN32
#include <winsock2.h>
#else
#include <arpa/inet.h> /* inet_ntoa */
#endif
#include <event2/event.h>
#include <event2/bufferevent.h>
#include "utp.h"
#include "transmission.h"
#include "session.h"
#include "bandwidth.h"
#include "crypto.h"
#include "list.h"
#include "net.h"
#include "peer-common.h" /* MAX_BLOCK_SIZE */
#include "peer-io.h"
#include "trevent.h" /* tr_runInEventThread() */
#include "utils.h"
#define MAGIC_NUMBER 206745
#ifdef WIN32
#define EAGAIN WSAEWOULDBLOCK
#define EINTR WSAEINTR
#define EINPROGRESS WSAEINPROGRESS
#define EPIPE WSAECONNRESET
#endif
static size_t
guessPacketOverhead( size_t d )
{
/**
* 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
*/
const double assumed_payload_data_rate = 94.0;
return (unsigned int)( d * ( 100.0 / assumed_payload_data_rate ) - d );
}
/**
***
**/
#define dbgmsg( io, ... ) \
do { \
if( tr_deepLoggingIsActive( ) ) \
tr_deepLog( __FILE__, __LINE__, tr_peerIoGetAddrStr( io ), __VA_ARGS__ ); \
} while( 0 )
struct tr_datatype
{
tr_bool isPieceData;
size_t length;
};
/***
****
***/
static void
didWriteWrapper( tr_peerIo * io, unsigned int bytes_transferred )
{
while( bytes_transferred && tr_isPeerIo( io ) )
{
struct tr_datatype * next = io->outbuf_datatypes->data;
const unsigned int payload = MIN( next->length, bytes_transferred );
const unsigned int overhead = guessPacketOverhead( payload );
const uint64_t now = tr_sessionGetTimeMsec( io->session );
tr_bandwidthUsed( &io->bandwidth, TR_UP, payload, next->isPieceData, now );
if( overhead > 0 )
tr_bandwidthUsed( &io->bandwidth, TR_UP, overhead, FALSE, now );
if( io->didWrite )
io->didWrite( io, payload, next->isPieceData, io->userData );
if( tr_isPeerIo( io ) )
{
bytes_transferred -= payload;
next->length -= payload;
if( !next->length ) {
tr_list_pop_front( &io->outbuf_datatypes );
tr_free( next );
}
}
}
}
static void
canReadWrapper( tr_peerIo * io )
{
tr_bool err = 0;
tr_bool done = 0;
tr_session * session;
dbgmsg( io, "canRead" );
assert( tr_isPeerIo( io ) );
assert( tr_isSession( io->session ) );
tr_peerIoRef( io );
session = io->session;
/* try to consume the input buffer */
if( io->canRead )
{
const uint64_t now = tr_sessionGetTimeMsec( io->session );
tr_sessionLock( session );
while( !done && !err )
{
size_t piece = 0;
const size_t oldLen = evbuffer_get_length( io->inbuf );
const int ret = io->canRead( io, io->userData, &piece );
const size_t used = oldLen - evbuffer_get_length( io->inbuf );
const unsigned int overhead = guessPacketOverhead( used );
assert( tr_isPeerIo( io ) );
if( piece || (piece!=used) )
{
if( piece )
tr_bandwidthUsed( &io->bandwidth, TR_DOWN, piece, TRUE, now );
if( used != piece )
tr_bandwidthUsed( &io->bandwidth, TR_DOWN, used - piece, FALSE, now );
}
if( overhead > 0 )
tr_bandwidthUsed( &io->bandwidth, TR_UP, overhead, FALSE, now );
switch( ret )
{
case READ_NOW:
if( evbuffer_get_length( io->inbuf ) )
continue;
done = 1;
break;
case READ_LATER:
done = 1;
break;
case READ_ERR:
err = 1;
break;
}
assert( tr_isPeerIo( io ) );
}
tr_sessionUnlock( session );
}
assert( tr_isPeerIo( io ) );
tr_peerIoUnref( io );
}
tr_bool
tr_isPeerIo( const tr_peerIo * io )
{
return ( io != NULL )
&& ( io->magicNumber == MAGIC_NUMBER )
&& ( io->refCount >= 0 )
&& ( tr_isBandwidth( &io->bandwidth ) )
&& ( tr_isAddress( &io->addr ) );
}
static void
event_read_cb( int fd, short event UNUSED, void * vio )
{
int res;
int e;
tr_peerIo * io = vio;
/* Limit the input buffer to 256K, so it doesn't grow too large */
unsigned int howmuch;
unsigned int curlen;
const tr_direction dir = TR_DOWN;
const unsigned int max = 256 * 1024;
assert( tr_isPeerIo( io ) );
assert( io->socket >= 0 );
io->pendingEvents &= ~EV_READ;
curlen = evbuffer_get_length( io->inbuf );
howmuch = curlen >= max ? 0 : max - curlen;
howmuch = tr_bandwidthClamp( &io->bandwidth, TR_DOWN, howmuch );
dbgmsg( io, "libevent says this peer is ready to read" );
/* if we don't have any bandwidth left, stop reading */
if( howmuch < 1 ) {
tr_peerIoSetEnabled( io, dir, FALSE );
return;
}
EVUTIL_SET_SOCKET_ERROR( 0 );
res = evbuffer_read( io->inbuf, fd, (int)howmuch );
e = EVUTIL_SOCKET_ERROR( );
if( res > 0 )
{
tr_peerIoSetEnabled( io, dir, TRUE );
/* Invoke the user callback - must always be called last */
canReadWrapper( io );
}
else
{
char errstr[512];
short what = BEV_EVENT_READING;
if( res == 0 ) /* EOF */
what |= BEV_EVENT_EOF;
else if( res == -1 ) {
if( e == EAGAIN || e == EINTR ) {
tr_peerIoSetEnabled( io, dir, TRUE );
return;
}
what |= BEV_EVENT_ERROR;
}
tr_net_strerror( errstr, sizeof( errstr ), e );
dbgmsg( io, "event_read_cb got an error. res is %d, what is %hd, errno is %d (%s)", res, what, e, errstr );
if( io->gotError != NULL )
io->gotError( io, what, io->userData );
}
}
static int
tr_evbuffer_write( tr_peerIo * io, int fd, size_t howmuch )
{
int e;
int n;
char errstr[256];
EVUTIL_SET_SOCKET_ERROR( 0 );
n = evbuffer_write_atmost( io->outbuf, fd, howmuch );
e = EVUTIL_SOCKET_ERROR( );
dbgmsg( io, "wrote %d to peer (%s)", n, (n==-1?tr_net_strerror(errstr,sizeof(errstr),e):"") );
return n;
}
static void
event_write_cb( int fd, short event UNUSED, void * vio )
{
int res = 0;
int e;
short what = BEV_EVENT_WRITING;
tr_peerIo * io = vio;
size_t howmuch;
const tr_direction dir = TR_UP;
assert( tr_isPeerIo( io ) );
assert( io->socket >= 0 );
io->pendingEvents &= ~EV_WRITE;
dbgmsg( io, "libevent says this peer is ready to write" );
/* Write as much as possible, since the socket is non-blocking, write() will
* return if it can't write any more data without blocking */
howmuch = tr_bandwidthClamp( &io->bandwidth, dir, evbuffer_get_length( io->outbuf ) );
/* if we don't have any bandwidth left, stop writing */
if( howmuch < 1 ) {
tr_peerIoSetEnabled( io, dir, FALSE );
return;
}
EVUTIL_SET_SOCKET_ERROR( 0 );
res = tr_evbuffer_write( io, fd, howmuch );
e = EVUTIL_SOCKET_ERROR( );
if (res == -1) {
if (!e || e == EAGAIN || e == EINTR || e == EINPROGRESS)
goto reschedule;
/* error case */
what |= BEV_EVENT_ERROR;
} else if (res == 0) {
/* eof case */
what |= BEV_EVENT_EOF;
}
if (res <= 0)
goto error;
if( evbuffer_get_length( io->outbuf ) )
tr_peerIoSetEnabled( io, dir, TRUE );
didWriteWrapper( io, res );
return;
reschedule:
if( evbuffer_get_length( io->outbuf ) )
tr_peerIoSetEnabled( io, dir, TRUE );
return;
error:
dbgmsg( io, "event_write_cb got an error. res is %d, what is %hd, errno is %d (%s)", res, what, e, strerror( e ) );
if( io->gotError != NULL )
io->gotError( io, what, io->userData );
}
/**
***
**/
static void
maybeSetCongestionAlgorithm( int socket, const char * algorithm )
{
if( algorithm && *algorithm )
{
const int rc = tr_netSetCongestionControl( socket, algorithm );
if( rc < 0 )
tr_ninf( "Net", "Can't set congestion control algorithm '%s': %s",
algorithm, tr_strerror( errno ));
}
}
/* UTP callbacks */
static void
utp_on_read(void *closure, const unsigned char *buf, size_t buflen)
{
int rc;
tr_peerIo *io = (tr_peerIo *)closure;
assert( tr_isPeerIo( io ) );
tr_ndbg( "UTP", "On read: %ld", (long)buflen );
rc = evbuffer_add( io->inbuf, buf, buflen );
if( rc < 0 ) {
tr_nerr( "UTP", "On read evbuffer_add" );
return;
}
tr_peerIoSetEnabled( io, TR_DOWN, TRUE );
canReadWrapper( io );
}
static void
utp_on_write(void *closure, unsigned char *buf, size_t buflen)
{
tr_peerIo *io = (tr_peerIo *)closure;
int rc;
assert( tr_isPeerIo( io ) );
tr_ndbg( "UTP", "On write: %ld", (long)buflen );
rc = evbuffer_remove( io->outbuf, buf, buflen );
if( rc < (long)buflen ) {
tr_nerr( "UTP", "Short write: %d < %ld", rc, (long)buflen);
}
}
static size_t
utp_get_rb_size(void *closure)
{
tr_peerIo *io = (tr_peerIo *)closure;
assert( tr_isPeerIo( io ) );
tr_ndbg( "UTP", "Get RB size" );
return 0;
}
static void
utp_on_state_change(void *closure, int state)
{
tr_peerIo *io = (tr_peerIo *)closure;
assert( tr_isPeerIo( io ) );
tr_ndbg( "UTP", "On state change: %d", state );
if( state == UTP_STATE_CONNECT || state == UTP_STATE_WRITABLE ) {
size_t count = evbuffer_get_length( io->outbuf );
if( count > 0 )
UTP_Write( io->utp_socket, count );
} else if( state == UTP_STATE_EOF ) {
if( io->gotError )
io->gotError( io, BEV_EVENT_EOF, io->userData );
} else if( state == UTP_STATE_DESTROYING ) {
tr_nerr( "UTP", "Impossible state UTP_STATE_DESTROYING" );
return;
} else {
tr_nerr( "UTP", "Unknown state %d", state );
}
}
static void
utp_on_error(void *closure, int errcode)
{
tr_peerIo *io = (tr_peerIo *)closure;
assert( tr_isPeerIo( io ) );
tr_ndbg( "UTP", "Error callback: %s", tr_strerror( errcode ) );
if( io->gotError ) {
errno = errcode;
io->gotError( io, BEV_EVENT_ERROR, io->userData );
}
}
static void
utp_on_overhead(void *closure, bool send, size_t count, int type)
{
tr_peerIo *io = (tr_peerIo *)closure;
assert( tr_isPeerIo( io ) );
tr_ndbg( "UTP", "On overhead: %d %ld %d", (int)send, (long)count, type );
}
static struct UTPFunctionTable utp_function_table = {
.on_read = utp_on_read,
.on_write = utp_on_write,
.get_rb_size = utp_get_rb_size,
.on_state = utp_on_state_change,
.on_error = utp_on_error,
.on_overhead = utp_on_overhead
};
/* Dummy UTP callbacks. */
/* We switch a UTP socket to use these after the associated peerIo has been
destroyed -- see io_dtor. */
static void
dummy_read(void *closure, const unsigned char *buf, size_t buflen)
{
/* This cannot happen, as far as I'm aware. */
tr_nerr("UTP", "On_read called on closed socket");
}
static void
dummy_write(void *closure, unsigned char *buf, size_t buflen)
{
/* This can very well happen if we've shut down a peer connection that
had unflushed buffers. Complain and send zeroes. */
tr_ndbg("UTP", "On_write called on closed socket");
memset(buf, 0, buflen);
}
static size_t
dummy_get_rb_size(void *closure)
{
return 0;
}
static void
dummy_on_state_change(void *closure, int state)
{
return;
}
static void
dummy_on_error(void *closure, int errcode)
{
return;
}
static void
dummy_on_overhead(void *closure, bool send, size_t count, int type)
{
return;
}
static struct UTPFunctionTable dummy_utp_function_table = {
.on_read = dummy_read,
.on_write = dummy_write,
.get_rb_size = dummy_get_rb_size,
.on_state = dummy_on_state_change,
.on_error = dummy_on_error,
.on_overhead = dummy_on_overhead
};
static tr_peerIo*
tr_peerIoNew( tr_session * session,
tr_bandwidth * parent,
const tr_address * addr,
tr_port port,
const uint8_t * torrentHash,
tr_bool isIncoming,
tr_bool isSeed,
int socket,
struct UTPSocket * utp_socket)
{
tr_peerIo * io;
assert( session != NULL );
assert( session->events != NULL );
assert( tr_isBool( isIncoming ) );
assert( tr_isBool( isSeed ) );
assert( tr_amInEventThread( session ) );
assert( (socket < 0) == (utp_socket != NULL) );
if( socket >= 0 ) {
tr_netSetTOS( socket, session->peerSocketTOS );
maybeSetCongestionAlgorithm( socket, session->peer_congestion_algorithm );
}
io = tr_new0( tr_peerIo, 1 );
io->magicNumber = MAGIC_NUMBER;
io->refCount = 1;
io->crypto = tr_cryptoNew( torrentHash, isIncoming );
io->session = session;
io->addr = *addr;
io->isSeed = isSeed;
io->port = port;
io->socket = socket;
io->utp_socket = utp_socket;
io->isIncoming = isIncoming != 0;
io->timeCreated = tr_time( );
io->inbuf = evbuffer_new( );
io->outbuf = evbuffer_new( );
tr_bandwidthConstruct( &io->bandwidth, session, parent );
tr_bandwidthSetPeer( &io->bandwidth, io );
dbgmsg( io, "bandwidth is %p; its parent is %p", &io->bandwidth, parent );
if( io->socket >= 0 ) {
io->event_read = event_new( session->event_base,
io->socket, EV_READ, event_read_cb, io );
io->event_write = event_new( session->event_base,
io->socket, EV_WRITE, event_write_cb, io );
} else {
tr_ndbg( "UTP", "New %s connection",
isIncoming ? "incoming" : "outgoing" );
UTP_SetCallbacks( utp_socket,
&utp_function_table,
io );
}
return io;
}
tr_peerIo*
tr_peerIoNewIncoming( tr_session * session,
tr_bandwidth * parent,
const tr_address * addr,
tr_port port,
int fd,
struct UTPSocket * utp_socket )
{
assert( session );
assert( tr_isAddress( addr ) );
return tr_peerIoNew( session, parent, addr, port, NULL, TRUE, FALSE,
fd, utp_socket );
}
tr_peerIo*
tr_peerIoNewOutgoing( tr_session * session,
tr_bandwidth * parent,
const tr_address * addr,
tr_port port,
const uint8_t * torrentHash,
tr_bool isSeed )
{
int fd;
assert( session );
assert( tr_isAddress( addr ) );
assert( torrentHash );
fd = tr_netOpenPeerSocket( session, addr, port, isSeed );
dbgmsg( NULL, "tr_netOpenPeerSocket returned fd %d", fd );
return fd < 0 ? NULL
: tr_peerIoNew( session, parent, addr, port,
torrentHash, FALSE, isSeed, fd, NULL );
}
/***
****
***/
static void
event_enable( tr_peerIo * io, short event )
{
assert( tr_amInEventThread( io->session ) );
assert( io->session != NULL );
assert( io->session->events != NULL );
if( io->socket < 0 )
return;
assert( io->session->events != NULL );
assert( event_initialized( io->event_read ) );
assert( event_initialized( io->event_write ) );
if( ( event & EV_READ ) && ! ( io->pendingEvents & EV_READ ) )
{
dbgmsg( io, "enabling libevent ready-to-read polling" );
event_add( io->event_read, NULL );
io->pendingEvents |= EV_READ;
}
if( ( event & EV_WRITE ) && ! ( io->pendingEvents & EV_WRITE ) )
{
dbgmsg( io, "enabling libevent ready-to-write polling" );
event_add( io->event_write, NULL );
io->pendingEvents |= EV_WRITE;
}
}
static void
event_disable( struct tr_peerIo * io, short event )
{
assert( tr_amInEventThread( io->session ) );
assert( io->session != NULL );
if( io->socket < 0 )
return;
assert( io->session->events != NULL );
assert( event_initialized( io->event_read ) );
assert( event_initialized( io->event_write ) );
if( ( event & EV_READ ) && ( io->pendingEvents & EV_READ ) )
{
dbgmsg( io, "disabling libevent ready-to-read polling" );
event_del( io->event_read );
io->pendingEvents &= ~EV_READ;
}
if( ( event & EV_WRITE ) && ( io->pendingEvents & EV_WRITE ) )
{
dbgmsg( io, "disabling libevent ready-to-write polling" );
event_del( io->event_write );
io->pendingEvents &= ~EV_WRITE;
}
}
void
tr_peerIoSetEnabled( tr_peerIo * io,
tr_direction dir,
tr_bool isEnabled )
{
const short event = dir == TR_UP ? EV_WRITE : EV_READ;
assert( tr_isPeerIo( io ) );
assert( tr_isDirection( dir ) );
assert( tr_amInEventThread( io->session ) );
assert( io->session->events != NULL );
if( isEnabled )
event_enable( io, event );
else
event_disable( io, event );
}
/***
****
***/
static void
io_dtor( void * vio )
{
tr_peerIo * io = vio;
assert( tr_isPeerIo( io ) );
assert( tr_amInEventThread( io->session ) );
assert( io->session->events != NULL );
dbgmsg( io, "in tr_peerIo destructor" );
event_disable( io, EV_READ | EV_WRITE );
tr_bandwidthDestruct( &io->bandwidth );
evbuffer_free( io->outbuf );
evbuffer_free( io->inbuf );
if( io->socket >= 0 ) {
event_free( io->event_read );
event_free( io->event_write );
tr_netClose( io->session, io->socket );
}
if( io->utp_socket != NULL ) {
tr_ndbg( "UTP", "Destroying connection");
UTP_SetCallbacks( io->utp_socket,
&dummy_utp_function_table,
NULL );
UTP_Close( io->utp_socket );
}
tr_cryptoFree( io->crypto );
tr_list_free( &io->outbuf_datatypes, tr_free );
memset( io, ~0, sizeof( tr_peerIo ) );
tr_free( io );
}
static void
tr_peerIoFree( tr_peerIo * io )
{
if( io )
{
dbgmsg( io, "in tr_peerIoFree" );
io->canRead = NULL;
io->didWrite = NULL;
io->gotError = NULL;
tr_runInEventThread( io->session, io_dtor, io );
}
}
void
tr_peerIoRefImpl( const char * file, int line, tr_peerIo * io )
{
assert( tr_isPeerIo( io ) );
dbgmsg( io, "%s:%d is incrementing the IO's refcount from %d to %d",
file, line, io->refCount, io->refCount+1 );
++io->refCount;
}
void
tr_peerIoUnrefImpl( const char * file, int line, tr_peerIo * io )
{
assert( tr_isPeerIo( io ) );
dbgmsg( io, "%s:%d is decrementing the IO's refcount from %d to %d",
file, line, io->refCount, io->refCount-1 );
if( !--io->refCount )
tr_peerIoFree( io );
}
const tr_address*
tr_peerIoGetAddress( const tr_peerIo * io, tr_port * port )
{
assert( tr_isPeerIo( io ) );
if( port )
*port = io->port;
return &io->addr;
}
const char*
tr_peerIoAddrStr( const tr_address * addr, tr_port port )
{
static char buf[512];
if( addr->type == TR_AF_INET )
tr_snprintf( buf, sizeof( buf ), "%s:%u", tr_ntop_non_ts( addr ), ntohs( port ) );
else
tr_snprintf( buf, sizeof( buf ), "[%s]:%u", tr_ntop_non_ts( addr ), ntohs( port ) );
return buf;
}
const char* tr_peerIoGetAddrStr( const tr_peerIo * io )
{
return tr_isPeerIo( io ) ? tr_peerIoAddrStr( &io->addr, io->port ) : "error";
}
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;
}
void
tr_peerIoClear( tr_peerIo * io )
{
tr_peerIoSetIOFuncs( io, NULL, NULL, NULL, NULL );
tr_peerIoSetEnabled( io, TR_UP, FALSE );
tr_peerIoSetEnabled( io, TR_DOWN, FALSE );
}
int
tr_peerIoReconnect( tr_peerIo * io )
{
short int pendingEvents;
tr_session * session;
assert( tr_isPeerIo( io ) );
assert( !tr_peerIoIsIncoming( io ) );
session = tr_peerIoGetSession( io );
pendingEvents = io->pendingEvents;
event_disable( io, EV_READ | EV_WRITE );
if( io->socket >= 0 ) {
tr_netClose( session, io->socket );
io->socket = -1;
}
if( io->utp_socket != NULL ) {
UTP_Close(io->utp_socket);
io->utp_socket = NULL;
}
event_free( io->event_read );
event_free( io->event_write );
io->socket = tr_netOpenPeerSocket( session, &io->addr, io->port, io->isSeed );
io->event_read = event_new( session->event_base, io->socket, EV_READ, event_read_cb, io );
io->event_write = event_new( session->event_base, io->socket, EV_WRITE, event_write_cb, io );
if( io->socket >= 0 )
{
event_enable( io, pendingEvents );
tr_netSetTOS( io->socket, session->peerSocketTOS );
maybeSetCongestionAlgorithm( io->socket, session->peer_congestion_algorithm );
return 0;
}
return -1;
}
/**
***
**/
void
tr_peerIoSetTorrentHash( tr_peerIo * io,
const uint8_t * hash )
{
assert( tr_isPeerIo( io ) );
tr_cryptoSetTorrentHash( io->crypto, hash );
}
const uint8_t*
tr_peerIoGetTorrentHash( tr_peerIo * io )
{
assert( tr_isPeerIo( io ) );
assert( io->crypto );
return tr_cryptoGetTorrentHash( io->crypto );
}
int
tr_peerIoHasTorrentHash( const tr_peerIo * io )
{
assert( tr_isPeerIo( io ) );
assert( io->crypto );
return tr_cryptoHasTorrentHash( io->crypto );
}
/**
***
**/
void
tr_peerIoSetPeersId( tr_peerIo * io,
const uint8_t * peer_id )
{
assert( tr_isPeerIo( io ) );
if( ( io->peerIdIsSet = peer_id != NULL ) )
memcpy( io->peerId, peer_id, 20 );
else
memset( io->peerId, 0, 20 );
}
/**
***
**/
static unsigned int
getDesiredOutputBufferSize( const tr_peerIo * io, uint64_t now )
{
/* this is all kind of arbitrary, but what seems to work well is
* being large enough to hold the next 20 seconds' worth of input,
* or a few blocks, whichever is bigger.
* It's okay to tweak this as needed */
const unsigned int currentSpeed_Bps = tr_bandwidthGetPieceSpeed_Bps( &io->bandwidth, now, TR_UP );
const unsigned int period = 15u; /* arbitrary */
/* the 3 is arbitrary; the .5 is to leave room for messages */
static const unsigned int ceiling = (unsigned int)( MAX_BLOCK_SIZE * 3.5 );
return MAX( ceiling, currentSpeed_Bps*period );
}
size_t
tr_peerIoGetWriteBufferSpace( const tr_peerIo * io, uint64_t now )
{
const size_t desiredLen = getDesiredOutputBufferSize( io, now );
const size_t currentLen = evbuffer_get_length( io->outbuf );
size_t freeSpace = 0;
if( desiredLen > currentLen )
freeSpace = desiredLen - currentLen;
return freeSpace;
}
/**
***
**/
void
tr_peerIoSetEncryption( tr_peerIo * io, uint32_t encryptionMode )
{
assert( tr_isPeerIo( io ) );
assert( encryptionMode == PEER_ENCRYPTION_NONE
|| encryptionMode == PEER_ENCRYPTION_RC4 );
io->encryptionMode = encryptionMode;
}
/**
***
**/
static void
addDatatype( tr_peerIo * io, size_t byteCount, tr_bool isPieceData )
{
struct tr_datatype * d;
d = tr_new( struct tr_datatype, 1 );
d->isPieceData = isPieceData != 0;
d->length = byteCount;
tr_list_append( &io->outbuf_datatypes, d );
}
static struct evbuffer_iovec *
evbuffer_peek_all( struct evbuffer * buf, size_t * setme_vecCount )
{
const size_t byteCount = evbuffer_get_length( buf );
const int vecCount = evbuffer_peek( buf, byteCount, NULL, NULL, 0 );
struct evbuffer_iovec * iovec = tr_new0( struct evbuffer_iovec, vecCount );
const int n = evbuffer_peek( buf, byteCount, NULL, iovec, vecCount );
assert( n == vecCount );
*setme_vecCount = n;
return iovec;
}
static void
maybeEncryptBuffer( tr_peerIo * io, struct evbuffer * buf )
{
if( io->encryptionMode == PEER_ENCRYPTION_RC4 )
{
size_t i, n;
struct evbuffer_iovec * iovec = evbuffer_peek_all( buf, &n );
for( i=0; i<n; ++i )
tr_cryptoEncrypt( io->crypto, iovec[i].iov_len, iovec[i].iov_base, iovec[i].iov_base );
tr_free( iovec );
}
}
void
tr_peerIoWriteBuf( tr_peerIo * io, struct evbuffer * buf, tr_bool isPieceData )
{
const size_t byteCount = evbuffer_get_length( buf );
maybeEncryptBuffer( io, buf );
evbuffer_add_buffer( io->outbuf, buf );
addDatatype( io, byteCount, isPieceData );
if( io->utp_socket )
UTP_Write( io->utp_socket, byteCount );
}
void
tr_peerIoWriteBytes( tr_peerIo * io, const void * bytes, size_t byteCount, tr_bool isPieceData )
{
struct evbuffer * buf = evbuffer_new( );
evbuffer_add( buf, bytes, byteCount );
tr_peerIoWriteBuf( io, buf, isPieceData );
evbuffer_free( buf );
}
/***
****
***/
void
evbuffer_add_uint8( struct evbuffer * outbuf, uint8_t byte )
{
evbuffer_add( outbuf, &byte, 1 );
}
void
evbuffer_add_uint16( struct evbuffer * outbuf, uint16_t addme_hs )
{
const uint16_t ns = htons( addme_hs );
evbuffer_add( outbuf, &ns, sizeof( ns ) );
}
void
evbuffer_add_uint32( struct evbuffer * outbuf, uint32_t addme_hl )
{
const uint32_t nl = htonl( addme_hl );
evbuffer_add( outbuf, &nl, sizeof( nl ) );
}
/***
****
***/
void
tr_peerIoReadBytes( tr_peerIo * io, struct evbuffer * inbuf, void * bytes, size_t byteCount )
{
assert( tr_isPeerIo( io ) );
assert( evbuffer_get_length( inbuf ) >= byteCount );
switch( io->encryptionMode )
{
case PEER_ENCRYPTION_NONE:
evbuffer_remove( inbuf, bytes, byteCount );
break;
case PEER_ENCRYPTION_RC4:
evbuffer_remove( inbuf, bytes, byteCount );
tr_cryptoDecrypt( io->crypto, byteCount, bytes, bytes );
break;
default:
assert( 0 );
}
}
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 )
{
void * buf = tr_sessionGetBuffer( io->session );
const size_t buflen = SESSION_BUFFER_SIZE;
while( byteCount > 0 )
{
const size_t thisPass = MIN( byteCount, buflen );
tr_peerIoReadBytes( io, inbuf, buf, thisPass );
byteCount -= thisPass;
}
tr_sessionReleaseBuffer( io->session );
}
/***
****
***/
static int
tr_peerIoTryRead( tr_peerIo * io, size_t howmuch )
{
int res = 0;
if(( howmuch = tr_bandwidthClamp( &io->bandwidth, TR_DOWN, howmuch )))
{
int e;
EVUTIL_SET_SOCKET_ERROR( 0 );
res = evbuffer_read( io->inbuf, io->socket, (int)howmuch );
e = EVUTIL_SOCKET_ERROR( );
dbgmsg( io, "read %d from peer (%s)", res, (res==-1?strerror(e):"") );
if( evbuffer_get_length( io->inbuf ) )
canReadWrapper( io );
if( ( res <= 0 ) && ( io->gotError ) && ( e != EAGAIN ) && ( e != EINTR ) && ( e != EINPROGRESS ) )
{
char errstr[512];
short what = BEV_EVENT_READING | BEV_EVENT_ERROR;
if( res == 0 )
what |= BEV_EVENT_EOF;
tr_net_strerror( errstr, sizeof( errstr ), e );
dbgmsg( io, "tr_peerIoTryRead got an error. res is %d, what is %hd, errno is %d (%s)", res, what, e, errstr );
io->gotError( io, what, io->userData );
}
}
return res;
}
static int
tr_peerIoTryWrite( tr_peerIo * io, size_t howmuch )
{
int n = 0;
if(( howmuch = tr_bandwidthClamp( &io->bandwidth, TR_UP, howmuch )))
{
int e;
EVUTIL_SET_SOCKET_ERROR( 0 );
n = tr_evbuffer_write( io, io->socket, howmuch );
e = EVUTIL_SOCKET_ERROR( );
if( n > 0 )
didWriteWrapper( io, n );
if( ( n < 0 ) && ( io->gotError ) && e && ( e != EPIPE ) && ( e != EAGAIN ) && ( e != EINTR ) && ( e != EINPROGRESS ) )
{
char errstr[512];
const short what = BEV_EVENT_WRITING | BEV_EVENT_ERROR;
tr_net_strerror( errstr, sizeof( errstr ), e );
dbgmsg( io, "tr_peerIoTryWrite got an error. res is %d, what is %hd, errno is %d (%s)", n, what, e, errstr );
if( io->gotError != NULL )
io->gotError( io, what, io->userData );
}
}
return n;
}
int
tr_peerIoFlush( tr_peerIo * io, tr_direction dir, size_t limit )
{
int bytesUsed = 0;
assert( tr_isPeerIo( io ) );
assert( tr_isDirection( dir ) );
if( dir == TR_DOWN )
bytesUsed = tr_peerIoTryRead( io, limit );
else
bytesUsed = tr_peerIoTryWrite( io, limit );
dbgmsg( io, "flushing peer-io, direction %d, limit %zu, bytesUsed %d", (int)dir, limit, bytesUsed );
return bytesUsed;
}
int
tr_peerIoFlushOutgoingProtocolMsgs( tr_peerIo * io )
{
size_t byteCount = 0;
tr_list * it;
/* count up how many bytes are used by non-piece-data messages
at the front of our outbound queue */
for( it=io->outbuf_datatypes; it!=NULL; it=it->next )
{
struct tr_datatype * d = it->data;
if( d->isPieceData )
break;
byteCount += d->length;
}
return tr_peerIoFlush( io, TR_UP, byteCount );
}
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