transmission/libtransmission/natpmp.c

254 lines
6.8 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;
}