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/*
* Copyright (c) 2003-2005 The Regents of The University of Michigan
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met: redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer;
* redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution;
* neither the name of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* Authors: Nathan Binkert
*/
/* @file
* Interface to connect a simulated ethernet device to the real world
*/
#include "dev/net/ethertap.hh"
#if defined(__OpenBSD__) || defined(__APPLE__)
#include <sys/param.h>
#endif
#if USE_TUNTAP && defined(__linux__)
#if 1 // Hide from the style checker since these have to be out of order.
#include <sys/socket.h> // Has to be included before if.h for some reason.
#endif
#include <linux/if.h>
#include <linux/if_tun.h>
#endif
#include <fcntl.h>
#include <netinet/in.h>
#include <sys/ioctl.h>
#include <unistd.h>
#include <cstring>
#include <deque>
#include <string>
#include "base/logging.hh"
#include "base/pollevent.hh"
#include "base/socket.hh"
#include "base/trace.hh"
#include "debug/Ethernet.hh"
#include "debug/EthernetData.hh"
#include "dev/net/etherdump.hh"
#include "dev/net/etherint.hh"
#include "dev/net/etherpkt.hh"
using namespace std;
class TapEvent : public PollEvent
{
protected:
EtherTapBase *tap;
public:
TapEvent(EtherTapBase *_tap, int fd, int e)
: PollEvent(fd, e), tap(_tap) {}
void
process(int revent) override
{
// Ensure that our event queue is active. It may not be since we get
// here from the PollQueue whenever a real packet happens to arrive.
EventQueue::ScopedMigration migrate(tap->eventQueue());
tap->recvReal(revent);
}
};
EtherTapBase::EtherTapBase(const Params *p)
: EtherObject(p), buflen(p->bufsz), dump(p->dump), event(NULL),
interface(NULL),
txEvent([this]{ retransmit(); }, "EtherTapBase retransmit")
{
buffer = new uint8_t[buflen];
interface = new EtherTapInt(name() + ".interface", this);
}
EtherTapBase::~EtherTapBase()
{
delete buffer;
delete event;
delete interface;
}
void
EtherTapBase::serialize(CheckpointOut &cp) const
{
SERIALIZE_SCALAR(buflen);
uint8_t *buffer = (uint8_t *)this->buffer;
SERIALIZE_ARRAY(buffer, buflen);
bool tapevent_present = false;
if (event) {
tapevent_present = true;
SERIALIZE_SCALAR(tapevent_present);
event->serialize(cp);
} else {
SERIALIZE_SCALAR(tapevent_present);
}
}
void
EtherTapBase::unserialize(CheckpointIn &cp)
{
UNSERIALIZE_SCALAR(buflen);
uint8_t *buffer = (uint8_t *)this->buffer;
UNSERIALIZE_ARRAY(buffer, buflen);
bool tapevent_present;
UNSERIALIZE_SCALAR(tapevent_present);
if (tapevent_present) {
event = new TapEvent(this, 0, 0);
event->unserialize(cp);
if (event->queued())
pollQueue.schedule(event);
}
}
void
EtherTapBase::pollFd(int fd)
{
assert(!event);
event = new TapEvent(this, fd, POLLIN|POLLERR);
pollQueue.schedule(event);
}
void
EtherTapBase::stopPolling()
{
assert(event);
delete event;
event = NULL;
}
EtherInt*
EtherTapBase::getEthPort(const std::string &if_name, int idx)
{
if (if_name == "tap") {
if (interface->getPeer())
panic("Interface already connected to\n");
return interface;
}
return NULL;
}
bool
EtherTapBase::recvSimulated(EthPacketPtr packet)
{
if (dump)
dump->dump(packet);
DPRINTF(Ethernet, "EtherTap sim->real len=%d\n", packet->length);
DDUMP(EthernetData, packet->data, packet->length);
bool success = sendReal(packet->data, packet->length);
interface->recvDone();
return success;
}
void
EtherTapBase::sendSimulated(void *data, size_t len)
{
EthPacketPtr packet;
packet = make_shared<EthPacketData>(len);
packet->length = len;
packet->simLength = len;
memcpy(packet->data, data, len);
DPRINTF(Ethernet, "EtherTap real->sim len=%d\n", packet->length);
DDUMP(EthernetData, packet->data, packet->length);
if (!packetBuffer.empty() || !interface->sendPacket(packet)) {
DPRINTF(Ethernet, "bus busy...buffer for retransmission\n");
packetBuffer.push(packet);
if (!txEvent.scheduled())
schedule(txEvent, curTick() + retryTime);
} else if (dump) {
dump->dump(packet);
}
}
void
EtherTapBase::retransmit()
{
if (packetBuffer.empty())
return;
EthPacketPtr packet = packetBuffer.front();
if (interface->sendPacket(packet)) {
if (dump)
dump->dump(packet);
DPRINTF(Ethernet, "EtherTap retransmit\n");
packetBuffer.front() = NULL;
packetBuffer.pop();
}
if (!packetBuffer.empty() && !txEvent.scheduled())
schedule(txEvent, curTick() + retryTime);
}
class TapListener
{
protected:
class Event : public PollEvent
{
protected:
TapListener *listener;
public:
Event(TapListener *l, int fd, int e) : PollEvent(fd, e), listener(l) {}
void process(int revent) override { listener->accept(); }
};
friend class Event;
Event *event;
void accept();
protected:
ListenSocket listener;
EtherTapStub *tap;
int port;
public:
TapListener(EtherTapStub *t, int p) : event(NULL), tap(t), port(p) {}
~TapListener() { delete event; }
void listen();
};
void
TapListener::listen()
{
while (!listener.listen(port, true)) {
DPRINTF(Ethernet, "TapListener(listen): Can't bind port %d\n", port);
port++;
}
ccprintf(cerr, "Listening for tap connection on port %d\n", port);
event = new Event(this, listener.getfd(), POLLIN|POLLERR);
pollQueue.schedule(event);
}
void
TapListener::accept()
{
// As a consequence of being called from the PollQueue, we might
// have been called from a different thread. Migrate to "our"
// thread.
EventQueue::ScopedMigration migrate(tap->eventQueue());
if (!listener.islistening())
panic("TapListener(accept): cannot accept if we're not listening!");
int sfd = listener.accept(true);
if (sfd != -1)
tap->attach(sfd);
}
EtherTapStub::EtherTapStub(const Params *p) : EtherTapBase(p), socket(-1)
{
if (ListenSocket::allDisabled())
fatal("All listeners are disabled! EtherTapStub can't work!");
listener = new TapListener(this, p->port);
listener->listen();
}
EtherTapStub::~EtherTapStub()
{
delete listener;
}
void
EtherTapStub::serialize(CheckpointOut &cp) const
{
EtherTapBase::serialize(cp);
SERIALIZE_SCALAR(socket);
SERIALIZE_SCALAR(buffer_used);
SERIALIZE_SCALAR(frame_len);
}
void
EtherTapStub::unserialize(CheckpointIn &cp)
{
EtherTapBase::unserialize(cp);
UNSERIALIZE_SCALAR(socket);
UNSERIALIZE_SCALAR(buffer_used);
UNSERIALIZE_SCALAR(frame_len);
}
void
EtherTapStub::attach(int fd)
{
if (socket != -1)
close(fd);
buffer_used = 0;
frame_len = 0;
socket = fd;
DPRINTF(Ethernet, "EtherTapStub attached\n");
pollFd(socket);
}
void
EtherTapStub::detach()
{
DPRINTF(Ethernet, "EtherTapStub detached\n");
stopPolling();
close(socket);
socket = -1;
}
void
EtherTapStub::recvReal(int revent)
{
if (revent & POLLERR) {
detach();
return;
}
if (!(revent & POLLIN))
return;
// Read in as much of the new data as we can.
int len = read(socket, buffer + buffer_used, buflen - buffer_used);
if (len == 0) {
detach();
return;
}
buffer_used += len;
// If there's not enough data for the frame length, wait for more.
if (buffer_used < sizeof(uint32_t))
return;
if (frame_len == 0)
frame_len = ntohl(*(uint32_t *)buffer);
DPRINTF(Ethernet, "Received data from peer: len=%d buffer_used=%d "
"frame_len=%d\n", len, buffer_used, frame_len);
uint8_t *frame_start = &buffer[sizeof(uint32_t)];
while (frame_len != 0 && buffer_used >= frame_len + sizeof(uint32_t)) {
sendSimulated(frame_start, frame_len);
// Bookkeeping.
buffer_used -= frame_len + sizeof(uint32_t);
if (buffer_used > 0) {
// If there's still any data left, move it into position.
memmove(buffer, frame_start + frame_len, buffer_used);
}
frame_len = 0;
if (buffer_used >= sizeof(uint32_t))
frame_len = ntohl(*(uint32_t *)buffer);
}
}
bool
EtherTapStub::sendReal(const void *data, size_t len)
{
uint32_t frame_len = htonl(len);
ssize_t ret = write(socket, &frame_len, sizeof(frame_len));
if (ret != sizeof(frame_len))
return false;
return write(socket, data, len) == len;
}
#if USE_TUNTAP
EtherTap::EtherTap(const Params *p) : EtherTapBase(p)
{
int fd = open(p->tun_clone_device.c_str(), O_RDWR | O_NONBLOCK);
if (fd < 0)
panic("Couldn't open %s.\n", p->tun_clone_device);
struct ifreq ifr;
memset(&ifr, 0, sizeof(ifr));
ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
strncpy(ifr.ifr_name, p->tap_device_name.c_str(), IFNAMSIZ - 1);
if (ioctl(fd, TUNSETIFF, (void *)&ifr) < 0)
panic("Failed to access tap device %s.\n", ifr.ifr_name);
// fd now refers to the tap device.
tap = fd;
pollFd(tap);
}
EtherTap::~EtherTap()
{
stopPolling();
close(tap);
tap = -1;
}
void
EtherTap::recvReal(int revent)
{
if (revent & POLLERR)
panic("Error polling for tap data.\n");
if (!(revent & POLLIN))
return;
ssize_t ret;
while ((ret = read(tap, buffer, buflen))) {
if (ret < 0) {
if (errno == EAGAIN)
break;
panic("Failed to read from tap device.\n");
}
sendSimulated(buffer, ret);
}
}
bool
EtherTap::sendReal(const void *data, size_t len)
{
int n;
pollfd pfd[1];
pfd->fd = tap;
pfd->events = POLLOUT;
// `tap` is a nonblock fd. Here we try to write until success, and use
// poll to make a blocking wait.
while ((n = write(tap, data, len)) != len) {
if (errno != EAGAIN)
panic("Failed to write data to tap device.\n");
pfd->revents = 0;
int ret = poll(pfd, 1, -1);
// timeout is set to inf, we shouldn't get 0 in any case.
assert(ret != 0);
if (ret == -1 || (ret == 1 && (pfd->revents & POLLERR))) {
panic("Failed when polling to write data to tap device.\n");
}
}
return true;
}
EtherTap *
EtherTapParams::create()
{
return new EtherTap(this);
}
#endif
EtherTapStub *
EtherTapStubParams::create()
{
return new EtherTapStub(this);
}