transmission/libtransmission/port-forwarding.cc

268 lines
5.6 KiB
C++

// This file Copyright © 2008-2022 Mnemosyne LLC.
// It may be used under GPLv2 (SPDX: GPL-2.0-only), GPLv3 (SPDX: GPL-3.0-only),
// or any future license endorsed by Mnemosyne LLC.
// License text can be found in the licenses/ folder.
#include <algorithm>
#include <string_view>
#include <sys/types.h>
#include <event2/event.h>
#include <fmt/core.h>
#include "transmission.h"
#include "natpmp_local.h"
#include "log.h"
#include "net.h"
#include "peer-mgr.h"
#include "port-forwarding.h"
#include "session.h"
#include "torrent.h"
#include "tr-assert.h"
#include "upnp.h"
#include "utils.h"
struct tr_shared
{
bool isEnabled;
bool isShuttingDown;
bool doPortCheck;
tr_port_forwarding natpmpStatus;
tr_port_forwarding upnpStatus;
tr_upnp* upnp;
tr_natpmp* natpmp;
tr_session* session;
struct event* timer;
};
/***
****
***/
static char const* getNatStateStr(int state)
{
switch (state)
{
case TR_PORT_MAPPING:
return _("Starting");
case TR_PORT_MAPPED:
return _("Forwarded");
case TR_PORT_UNMAPPING:
return _("Stopping");
case TR_PORT_UNMAPPED:
return _("Not forwarded");
default:
return "???";
}
}
static void natPulse(tr_shared* s, bool do_check)
{
auto* session = s->session;
tr_port const private_peer_port = session->private_peer_port;
bool const is_enabled = s->isEnabled && !s->isShuttingDown;
if (s->natpmp == nullptr)
{
s->natpmp = tr_natpmpInit();
}
if (s->upnp == nullptr)
{
s->upnp = tr_upnpInit();
}
auto const old_status = tr_sharedTraversalStatus(s);
auto public_peer_port = tr_port{};
auto received_private_port = tr_port{};
s->natpmpStatus = tr_natpmpPulse(s->natpmp, private_peer_port, is_enabled, &public_peer_port, &received_private_port);
if (s->natpmpStatus == TR_PORT_MAPPED)
{
session->public_peer_port = public_peer_port;
session->private_peer_port = received_private_port;
tr_logAddInfo(fmt::format(
_("Mapped private port {private_port} to public port {public_port}"),
fmt::arg("public_port", session->public_peer_port),
fmt::arg("private_port", session->private_peer_port)));
}
s->upnpStatus = tr_upnpPulse(
s->upnp,
private_peer_port,
is_enabled,
do_check,
tr_address_to_string(&session->bind_ipv4->addr));
auto const new_status = tr_sharedTraversalStatus(s);
if (new_status != old_status)
{
tr_logAddInfo(fmt::format(
_("State changed from '{old_state}' to '{state}"),
fmt::arg("old_state", getNatStateStr(old_status)),
fmt::arg("state", getNatStateStr(new_status))));
}
}
static void set_evtimer_from_status(tr_shared* s)
{
int sec = 0;
int msec = 0;
/* when to wake up again */
switch (tr_sharedTraversalStatus(s))
{
case TR_PORT_MAPPED:
/* if we're mapped, everything is fine... check back at renew_time
* to renew the port forwarding if it's expired */
s->doPortCheck = true;
sec = std::max(0, int(s->natpmp->renew_time - tr_time()));
break;
case TR_PORT_ERROR:
/* some kind of an error. wait 60 seconds and retry */
sec = 60;
break;
default:
/* in progress. pulse frequently. */
msec = 333000;
break;
}
if (s->timer != nullptr)
{
tr_timerAdd(s->timer, sec, msec);
}
}
static void onTimer(evutil_socket_t /*fd*/, short /*what*/, void* vshared)
{
auto* s = static_cast<tr_shared*>(vshared);
TR_ASSERT(s != nullptr);
TR_ASSERT(s->timer != nullptr);
/* do something */
natPulse(s, s->doPortCheck);
s->doPortCheck = false;
/* set up the timer for the next pulse */
set_evtimer_from_status(s);
}
/***
****
***/
tr_shared* tr_sharedInit(tr_session* session)
{
auto* const s = tr_new0(tr_shared, 1);
s->session = session;
s->isEnabled = false;
s->upnpStatus = TR_PORT_UNMAPPED;
s->natpmpStatus = TR_PORT_UNMAPPED;
#if 0
if (isEnabled)
{
s->timer = tr_new0(struct event, 1);
evtimer_set(s->timer, onTimer, s);
tr_timerAdd(s->timer, 0, 333000);
}
#endif
return s;
}
static void stop_timer(tr_shared* s)
{
if (s->timer != nullptr)
{
event_free(s->timer);
s->timer = nullptr;
}
}
static void stop_forwarding(tr_shared* s)
{
tr_logAddTrace("stopped");
natPulse(s, false);
tr_natpmpClose(s->natpmp);
s->natpmp = nullptr;
s->natpmpStatus = TR_PORT_UNMAPPED;
tr_upnpClose(s->upnp);
s->upnp = nullptr;
s->upnpStatus = TR_PORT_UNMAPPED;
stop_timer(s);
}
void tr_sharedClose(tr_session* session)
{
tr_shared* s = session->shared;
s->isShuttingDown = true;
stop_forwarding(s);
s->session->shared = nullptr;
tr_free(s);
}
static void start_timer(tr_shared* s)
{
s->timer = evtimer_new(s->session->event_base, onTimer, s);
set_evtimer_from_status(s);
}
void tr_sharedTraversalEnable(tr_shared* s, bool enable)
{
if (enable)
{
s->isEnabled = true;
start_timer(s);
}
else
{
s->isEnabled = false;
stop_forwarding(s);
}
}
void tr_sharedPortChanged(tr_session* session)
{
tr_shared* s = session->shared;
if (s->isEnabled)
{
stop_timer(s);
natPulse(s, false);
start_timer(s);
}
}
bool tr_sharedTraversalIsEnabled(tr_shared const* s)
{
return s->isEnabled;
}
int tr_sharedTraversalStatus(tr_shared const* s)
{
return std::max(s->natpmpStatus, s->upnpStatus);
}