transmission/libtransmission/natpmp.c

219 lines
6.2 KiB
C

/*
* 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 <time.h>
#include <inttypes.h>
#include <string.h> /* strerror */
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <libnatpmp/natpmp.h>
#include "transmission.h"
#include "natpmp.h"
#include "shared.h"
#include "utils.h"
#define LIFETIME_SECS 3600
#define COMMAND_WAIT_SECS 8
#define KEY "Port Mapping (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
{
int port;
unsigned int isMapped : 1;
unsigned int hasDiscovered : 1;
time_t renewTime;
time_t commandTime;
tr_natpmp_state state;
natpmp_t natpmp;
};
/**
***
**/
static void
logVal( const char * func, int ret )
{
if( ret==NATPMP_TRYAGAIN )
tr_dbg( KEY "%s returned 'try again'", func );
else if( ret >= 0 )
tr_dbg( KEY "%s returned success (%d)", func, ret );
else
tr_err( KEY "%s returned error %d, errno is %d (%s)", func, ret, errno, 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->port = -1;
return nat;
}
void
tr_natpmpClose( tr_natpmp * nat )
{
assert( !nat->isMapped );
assert( ( nat->state == TR_NATPMP_IDLE )
|| ( nat->state == TR_NATPMP_ERR )
|| ( nat->state == TR_NATPMP_DISCOVER ) );
closenatpmp( &nat->natpmp );
tr_free( nat );
}
static int
canSendCommand( const struct tr_natpmp * nat )
{
return time(NULL) >= nat->commandTime;
}
static void
setCommandTime( struct tr_natpmp * nat )
{
nat->commandTime = time(NULL) + COMMAND_WAIT_SECS;
}
static void
setErrorState( struct tr_natpmp * nat )
{
tr_err( KEY "If your router supports NAT-PMP, please make sure NAT-PMP is enabled!" );
tr_err( KEY "NAT-PMP port forwarding unsuccessful, trying UPnP next" );
nat->state = TR_NATPMP_ERR;
}
int
tr_natpmpPulse( struct tr_natpmp * nat, int port, int isEnabled )
{
int ret;
if( isEnabled && ( nat->state == TR_NATPMP_DISCOVER ) )
{
int val = initnatpmp( &nat->natpmp );
logVal( "initnatpmp", val );
val = sendpublicaddressrequest( &nat->natpmp );
logVal( "sendpublicaddressrequest", val );
nat->state = val < 0 ? TR_NATPMP_ERR : TR_NATPMP_RECV_PUB;
nat->hasDiscovered = 1;
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 ) {
tr_inf( KEY "found public address %s", inet_ntoa( response.publicaddress.addr ) );
nat->state = TR_NATPMP_IDLE;
} else if( val != NATPMP_TRYAGAIN ) {
setErrorState( nat );
}
}
if( ( nat->state == TR_NATPMP_IDLE ) || ( nat->state == TR_NATPMP_ERR ) )
{
if( nat->isMapped && ( !isEnabled || ( nat->port != 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->port, nat->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 ) {
tr_inf( KEY "port %d has been unmapped.", nat->port );
nat->state = TR_NATPMP_IDLE;
nat->port = -1;
nat->isMapped = 0;
} else if( val != NATPMP_TRYAGAIN ) {
setErrorState( nat );
}
}
if( nat->state == TR_NATPMP_IDLE )
{
if( isEnabled && !nat->isMapped && nat->hasDiscovered )
nat->state = TR_NATPMP_SEND_MAP;
else if( nat->isMapped && time(NULL) >= nat->renewTime )
nat->state = TR_NATPMP_SEND_MAP;
}
if( ( nat->state == TR_NATPMP_SEND_MAP ) && canSendCommand( nat ) )
{
const int val = sendnewportmappingrequest( &nat->natpmp, NATPMP_PROTOCOL_TCP, port, 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->isMapped = 1;
nat->renewTime = time( NULL ) + LIFETIME_SECS;
nat->port = resp.newportmapping.privateport;
tr_inf( KEY "port %d mapped successfully", nat->port );
} else if( val != NATPMP_TRYAGAIN ) {
setErrorState( nat );
}
}
switch( nat->state ) {
case TR_NATPMP_IDLE: ret = nat->isMapped ? TR_NAT_TRAVERSAL_MAPPED : TR_NAT_TRAVERSAL_UNMAPPED; break;
case TR_NATPMP_DISCOVER: ret = TR_NAT_TRAVERSAL_UNMAPPED; break;
case TR_NATPMP_RECV_PUB:
case TR_NATPMP_SEND_MAP:
case TR_NATPMP_RECV_MAP: ret = TR_NAT_TRAVERSAL_MAPPING; break;
case TR_NATPMP_SEND_UNMAP:
case TR_NATPMP_RECV_UNMAP: ret = TR_NAT_TRAVERSAL_UNMAPPING; break;
default: ret = TR_NAT_TRAVERSAL_ERROR; break;
}
return ret;
}