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/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/**
* Copyright (c) 2014 Regents of the University of California,
* Arizona Board of Regents,
* Colorado State University,
* University Pierre & Marie Curie, Sorbonne University,
* Washington University in St. Louis,
* Beijing Institute of Technology
*
* This file is part of NFD (Named Data Networking Forwarding Daemon).
* See AUTHORS.md for complete list of NFD authors and contributors.
*
* NFD is free software: you can redistribute it and/or modify it under the terms
* of the GNU General Public License as published by the Free Software Foundation,
* either version 3 of the License, or (at your option) any later version.
*
* NFD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
* without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
* PURPOSE. See the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along with
* NFD, e.g., in COPYING.md file. If not, see <http://www.gnu.org/licenses/>.
**/
#include "udp-face.hpp"
#ifdef __linux__
#include <netinet/in.h> // for IP_MTU_DISCOVER and IP_PMTUDISC_DONT
#include <sys/socket.h> // for setsockopt()
#endif
namespace nfd {
NFD_LOG_INCLASS_TEMPLATE_SPECIALIZATION_DEFINE(DatagramFace, UdpFace::protocol, "UdpFace");
UdpFace::UdpFace(const shared_ptr<UdpFace::protocol::socket>& socket,
bool isOnDemand,
const time::seconds& idleTimeout)
: DatagramFace<protocol>(FaceUri(socket->remote_endpoint()),
FaceUri(socket->local_endpoint()),
socket, isOnDemand)
, m_idleTimeout(idleTimeout)
, m_lastIdleCheck(time::steady_clock::now())
{
#ifdef __linux__
//
// By default, Linux does path MTU discovery on IPv4 sockets,
// and sets the DF (Don't Fragment) flag on datagrams smaller
// than the interface MTU. However this does not work for us,
// because we cannot properly respond to ICMP "packet too big"
// messages by fragmenting the packet at the application level,
// since we want to rely on IP for fragmentation and reassembly.
//
// Therefore, we disable PMTU discovery, which prevents the kernel
// from setting the DF flag on outgoing datagrams, and thus allows
// routers along the path to perform fragmentation as needed.
//
const int value = IP_PMTUDISC_DONT;
if (::setsockopt(socket->native_handle(), IPPROTO_IP,
IP_MTU_DISCOVER, &value, sizeof(value)) < 0)
{
NFD_LOG_WARN("[id:" << this->getId()
<< ",endpoint:" << m_socket->local_endpoint()
<< "] Failed to disable path MTU discovery");
}
#endif
if (isOnDemand && m_idleTimeout > time::seconds::zero()) {
m_closeIfIdleEvent = scheduler::schedule(m_idleTimeout,
bind(&UdpFace::closeIfIdle, this));
}
}
UdpFace::~UdpFace()
{
scheduler::cancel(m_closeIfIdleEvent);
}
ndn::nfd::FaceStatus
UdpFace::getFaceStatus() const
{
ndn::nfd::FaceStatus status = Face::getFaceStatus();
if (isOnDemand()) {
time::milliseconds left = m_idleTimeout - time::duration_cast<time::milliseconds>(
time::steady_clock::now() - m_lastIdleCheck);
if (left < time::milliseconds::zero())
left = time::milliseconds::zero();
if (hasBeenUsedRecently()) {
status.setExpirationPeriod(left + m_idleTimeout);
}
else {
status.setExpirationPeriod(left);
}
}
return status;
}
void
UdpFace::closeIfIdle()
{
// Face can be switched from on-demand to non-on-demand mode
// (non-on-demand -> on-demand transition is not allowed)
if (isOnDemand()) {
if (!hasBeenUsedRecently()) {
// face has been idle since the last time closeIfIdle
// has been called. Going to close it
NFD_LOG_DEBUG("Found idle face id: " << getId());
NFD_LOG_INFO("[id:" << this->getId()
<< ",endpoint:" << m_socket->local_endpoint()
<< "] Idle for more than " << m_idleTimeout << ", closing");
close();
}
else {
resetRecentUsage();
m_lastIdleCheck = time::steady_clock::now();
m_closeIfIdleEvent = scheduler::schedule(m_idleTimeout,
bind(&UdpFace::closeIfIdle, this));
}
}
// else do nothing and do not reschedule the event
}
} // namespace nfd