transmission/libtransmission/natpmp.cc

261 lines
6.5 KiB
C++

/*
* This file Copyright (C) 2007-2014 Mnemosyne LLC
*
* It may be used under the GNU GPL versions 2 or 3
* or any future license endorsed by Mnemosyne LLC.
*
*/
#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 "log.h"
#include "net.h" /* tr_netCloseSocket */
#include "port-forwarding.h"
#include "utils.h"
#define LIFETIME_SECS 3600
#define COMMAND_WAIT_SECS 8
static char const* getKey(void)
{
return _("Port Forwarding (NAT-PMP)");
}
enum tr_natpmp_state
{
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
};
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(char const* func, int ret)
{
if (ret == NATPMP_TRYAGAIN)
{
return;
}
if (ret >= 0)
{
tr_logAddNamedInfo(getKey(), _("%s succeeded (%d)"), func, ret);
}
else
{
tr_logAddNamedDbg(
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 = TR_BAD_SOCKET; /* socket */
return nat;
}
void tr_natpmpClose(tr_natpmp* nat)
{
if (nat != nullptr)
{
closenatpmp(&nat->natpmp);
tr_free(nat);
}
}
static bool canSendCommand(struct tr_natpmp const* nat)
{
return tr_time() >= nat->command_time;
}
static void setCommandTime(struct tr_natpmp* nat)
{
nat->command_time = tr_time() + COMMAND_WAIT_SECS;
}
tr_port_forwarding tr_natpmpPulse(struct tr_natpmp* nat, tr_port private_port, bool is_enabled, tr_port* public_port)
{
tr_port_forwarding 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;
int const 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_logAddNamedInfo(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) && (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))
{
int const 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;
int const val = readnatpmpresponseorretry(&nat->natpmp, &resp);
logVal("readnatpmpresponseorretry", val);
if (val >= 0)
{
int const unmapped_port = resp.pnu.newportmapping.privateport;
tr_logAddNamedInfo(getKey(), _("no longer forwarding port %d"), unmapped_port);
if (nat->private_port == unmapped_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))
{
int const 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;
int const 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_logAddNamedInfo(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;
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;
}