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transmission/libtransmission/natpmp.c

253 lines
6.9 KiB
C

/*
* 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 <errno.h>
#include <time.h>
#include <inttypes.h>
#include <event2/util.h> /* evutil_inet_ntop() */
#define ENABLE_STRNATPMPERR
#include "natpmp.h"
#include "transmission.h"
#include "natpmp_local.h"
#include "net.h" /* tr_netCloseSocket */
#include "port-forwarding.h"
#include "utils.h"
#define LIFETIME_SECS 3600
#define COMMAND_WAIT_SECS 8
static const char *
getKey( void ) { return _( "Port Forwarding (NAT-PMP)" ); }
typedef enum
{
TR_NATPMP_IDLE,
TR_NATPMP_ERR,
TR_NATPMP_DISCOVER,
TR_NATPMP_RECV_PUB,
TR_NATPMP_SEND_MAP,
TR_NATPMP_RECV_MAP,
TR_NATPMP_SEND_UNMAP,
TR_NATPMP_RECV_UNMAP
}
tr_natpmp_state;
struct tr_natpmp
{
bool has_discovered;
bool is_mapped;
tr_port public_port;
tr_port private_port;
time_t renew_time;
time_t command_time;
tr_natpmp_state state;
natpmp_t natpmp;
};
/**
***
**/
static void
logVal( const char * func,
int ret )
{
if( ret == NATPMP_TRYAGAIN )
return;
if( ret >= 0 )
tr_ninf( getKey( ), _( "%s succeeded (%d)" ), func, ret );
else
tr_ndbg(
getKey( ),
"%s failed. Natpmp returned %d (%s); errno is %d (%s)",
func, ret, strnatpmperr( ret ), errno, tr_strerror( errno ) );
}
struct tr_natpmp*
tr_natpmpInit( void )
{
struct tr_natpmp * nat;
nat = tr_new0( struct tr_natpmp, 1 );
nat->state = TR_NATPMP_DISCOVER;
nat->public_port = 0;
nat->private_port = 0;
nat->natpmp.s = -1; /* socket */
return nat;
}
void
tr_natpmpClose( tr_natpmp * nat )
{
if( nat )
{
if( nat->natpmp.s >= 0 )
tr_netCloseSocket( nat->natpmp.s );
tr_free( nat );
}
}
static int
canSendCommand( const struct tr_natpmp * nat )
{
return tr_time( ) >= nat->command_time;
}
static void
setCommandTime( struct tr_natpmp * nat )
{
nat->command_time = tr_time( ) + COMMAND_WAIT_SECS;
}
int
tr_natpmpPulse( struct tr_natpmp * nat, tr_port private_port, bool is_enabled, tr_port * public_port )
{
int ret;
if( is_enabled && ( nat->state == TR_NATPMP_DISCOVER ) )
{
int val = initnatpmp( &nat->natpmp, 0, 0 );
logVal( "initnatpmp", val );
val = sendpublicaddressrequest( &nat->natpmp );
logVal( "sendpublicaddressrequest", val );
nat->state = val < 0 ? TR_NATPMP_ERR : TR_NATPMP_RECV_PUB;
nat->has_discovered = true;
setCommandTime( nat );
}
if( ( nat->state == TR_NATPMP_RECV_PUB ) && canSendCommand( nat ) )
{
natpmpresp_t response;
const int val = readnatpmpresponseorretry( &nat->natpmp, &response );
logVal( "readnatpmpresponseorretry", val );
if( val >= 0 )
{
char str[128];
evutil_inet_ntop( AF_INET, &response.pnu.publicaddress.addr, str, sizeof( str ) );
tr_ninf( getKey( ), _( "Found public address \"%s\"" ), str );
nat->state = TR_NATPMP_IDLE;
}
else if( val != NATPMP_TRYAGAIN )
{
nat->state = TR_NATPMP_ERR;
}
}
if( ( nat->state == TR_NATPMP_IDLE ) || ( nat->state == TR_NATPMP_ERR ) )
{
if( nat->is_mapped && ( !is_enabled || ( nat->private_port != private_port ) ) )
nat->state = TR_NATPMP_SEND_UNMAP;
}
if( ( nat->state == TR_NATPMP_SEND_UNMAP ) && canSendCommand( nat ) )
{
const int val = sendnewportmappingrequest( &nat->natpmp, NATPMP_PROTOCOL_TCP,
nat->private_port,
nat->public_port,
0 );
logVal( "sendnewportmappingrequest", val );
nat->state = val < 0 ? TR_NATPMP_ERR : TR_NATPMP_RECV_UNMAP;
setCommandTime( nat );
}
if( nat->state == TR_NATPMP_RECV_UNMAP )
{
natpmpresp_t resp;
const int val = readnatpmpresponseorretry( &nat->natpmp, &resp );
logVal( "readnatpmpresponseorretry", val );
if( val >= 0 )
{
const int private_port = resp.pnu.newportmapping.privateport;
tr_ninf( getKey( ), _( "no longer forwarding port %d" ), private_port );
if( nat->private_port == private_port )
{
nat->private_port = 0;
nat->public_port = 0;
nat->state = TR_NATPMP_IDLE;
nat->is_mapped = false;
}
}
else if( val != NATPMP_TRYAGAIN )
{
nat->state = TR_NATPMP_ERR;
}
}
if( nat->state == TR_NATPMP_IDLE )
{
if( is_enabled && !nat->is_mapped && nat->has_discovered )
nat->state = TR_NATPMP_SEND_MAP;
else if( nat->is_mapped && tr_time( ) >= nat->renew_time )
nat->state = TR_NATPMP_SEND_MAP;
}
if( ( nat->state == TR_NATPMP_SEND_MAP ) && canSendCommand( nat ) )
{
const int val = sendnewportmappingrequest( &nat->natpmp, NATPMP_PROTOCOL_TCP, private_port, private_port, LIFETIME_SECS );
logVal( "sendnewportmappingrequest", val );
nat->state = val < 0 ? TR_NATPMP_ERR : TR_NATPMP_RECV_MAP;
setCommandTime( nat );
}
if( nat->state == TR_NATPMP_RECV_MAP )
{
natpmpresp_t resp;
const int val = readnatpmpresponseorretry( &nat->natpmp, &resp );
logVal( "readnatpmpresponseorretry", val );
if( val >= 0 )
{
nat->state = TR_NATPMP_IDLE;
nat->is_mapped = true;
nat->renew_time = tr_time( ) + ( resp.pnu.newportmapping.lifetime / 2 );
nat->private_port = resp.pnu.newportmapping.privateport;
nat->public_port = resp.pnu.newportmapping.mappedpublicport;
tr_ninf( getKey( ), _( "Port %d forwarded successfully" ), nat->private_port );
}
else if( val != NATPMP_TRYAGAIN )
{
nat->state = TR_NATPMP_ERR;
}
}
switch( nat->state )
{
case TR_NATPMP_IDLE:
*public_port = nat->public_port;
return nat->is_mapped ? TR_PORT_MAPPED : TR_PORT_UNMAPPED;
break;
case TR_NATPMP_DISCOVER:
ret = TR_PORT_UNMAPPED; break;
case TR_NATPMP_RECV_PUB:
case TR_NATPMP_SEND_MAP:
case TR_NATPMP_RECV_MAP:
ret = TR_PORT_MAPPING; break;
case TR_NATPMP_SEND_UNMAP:
case TR_NATPMP_RECV_UNMAP:
ret = TR_PORT_UNMAPPING; break;
default:
ret = TR_PORT_ERROR; break;
}
return ret;
}