ethertap.cc revision 12054:ab04045965d1 
1/*
2 * Copyright (c) 2003-2005 The Regents of The University of Michigan
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are
7 * met: redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer;
9 * redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution;
12 * neither the name of the copyright holders nor the names of its
13 * contributors may be used to endorse or promote products derived from
14 * this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
20 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 *
28 * Authors: Nathan Binkert
29 */
30
31/* @file
32 * Interface to connect a simulated ethernet device to the real world
33 */
34
35#include "dev/net/ethertap.hh"
36
37#if defined(__OpenBSD__) || defined(__APPLE__)
38#include <sys/param.h>
39
40#endif
41#include <netinet/in.h>
42#include <unistd.h>
43
44#include <deque>
45#include <string>
46
47#include "base/misc.hh"
48#include "base/pollevent.hh"
49#include "base/socket.hh"
50#include "base/trace.hh"
51#include "debug/Ethernet.hh"
52#include "debug/EthernetData.hh"
53#include "dev/net/etherdump.hh"
54#include "dev/net/etherint.hh"
55#include "dev/net/etherpkt.hh"
56
57using namespace std;
58
59/**
60 */
61class TapListener
62{
63  protected:
64    /**
65     */
66    class Event : public PollEvent
67    {
68      protected:
69        TapListener *listener;
70
71      public:
72        Event(TapListener *l, int fd, int e)
73            : PollEvent(fd, e), listener(l) {}
74
75        virtual void process(int revent) { listener->accept(); }
76    };
77
78    friend class Event;
79    Event *event;
80
81  protected:
82    ListenSocket listener;
83    EtherTapStub *tap;
84    int port;
85
86  public:
87    TapListener(EtherTapStub *t, int p)
88        : event(NULL), tap(t), port(p) {}
89    ~TapListener() { if (event) delete event; }
90
91    void accept();
92    void listen();
93};
94
95void
96TapListener::listen()
97{
98    while (!listener.listen(port, true)) {
99        DPRINTF(Ethernet, "TapListener(listen): Can't bind port %d\n", port);
100        port++;
101    }
102
103    ccprintf(cerr, "Listening for tap connection on port %d\n", port);
104    event = new Event(this, listener.getfd(), POLLIN|POLLERR);
105    pollQueue.schedule(event);
106}
107
108void
109TapListener::accept()
110{
111    // As a consequence of being called from the PollQueue, we might
112    // have been called from a different thread. Migrate to "our"
113    // thread.
114    EventQueue::ScopedMigration migrate(tap->eventQueue());
115
116    if (!listener.islistening())
117        panic("TapListener(accept): cannot accept if we're not listening!");
118
119    int sfd = listener.accept(true);
120    if (sfd != -1)
121        tap->attach(sfd);
122}
123
124/**
125 */
126class TapEvent : public PollEvent
127{
128  protected:
129    EtherTapStub *tap;
130
131  public:
132    TapEvent(EtherTapStub *_tap, int fd, int e)
133        : PollEvent(fd, e), tap(_tap) {}
134    virtual void process(int revent) { tap->process(revent); }
135};
136
137EtherTapStub::EtherTapStub(const Params *p)
138    : EtherObject(p), event(NULL), socket(-1), buflen(p->bufsz), dump(p->dump),
139      interface(NULL), txEvent(this)
140{
141    if (ListenSocket::allDisabled())
142        fatal("All listeners are disabled! EtherTapStub can't work!");
143
144    buffer = new char[buflen];
145    listener = new TapListener(this, p->port);
146    listener->listen();
147    interface = new EtherTapInt(name() + ".interface", this);
148}
149
150EtherTapStub::~EtherTapStub()
151{
152    if (event)
153        delete event;
154    if (buffer)
155        delete [] buffer;
156
157    delete interface;
158    delete listener;
159}
160
161void
162EtherTapStub::attach(int fd)
163{
164    if (socket != -1)
165        close(fd);
166
167    buffer_offset = 0;
168    data_len = 0;
169    socket = fd;
170    DPRINTF(Ethernet, "EtherTapStub attached\n");
171    event = new TapEvent(this, socket, POLLIN|POLLERR);
172    pollQueue.schedule(event);
173}
174
175void
176EtherTapStub::detach()
177{
178    DPRINTF(Ethernet, "EtherTapStub detached\n");
179    delete event;
180    event = 0;
181    close(socket);
182    socket = -1;
183}
184
185bool
186EtherTapStub::recvPacket(EthPacketPtr packet)
187{
188    if (dump)
189        dump->dump(packet);
190
191    DPRINTF(Ethernet, "EtherTapStub output len=%d\n", packet->length);
192    DDUMP(EthernetData, packet->data, packet->length);
193    uint32_t len = htonl(packet->length);
194    ssize_t ret = write(socket, &len, sizeof(len));
195    if (ret != sizeof(len))
196        return false;
197    ret = write(socket, packet->data, packet->length);
198    if (ret != packet->length)
199        return false;
200
201    interface->recvDone();
202
203    return true;
204}
205
206void
207EtherTapStub::sendDone()
208{}
209
210void
211EtherTapStub::process(int revent)
212{
213    if (revent & POLLERR) {
214        detach();
215        return;
216    }
217
218    char *data = buffer + sizeof(uint32_t);
219    if (!(revent & POLLIN))
220        return;
221
222    if (buffer_offset < data_len + sizeof(uint32_t)) {
223        int len = read(socket, buffer + buffer_offset, buflen - buffer_offset);
224        if (len == 0) {
225            detach();
226            return;
227        }
228
229        buffer_offset += len;
230
231        if (data_len == 0)
232            data_len = ntohl(*(uint32_t *)buffer);
233
234        DPRINTF(Ethernet, "Received data from peer: len=%d buffer_offset=%d "
235                "data_len=%d\n", len, buffer_offset, data_len);
236    }
237
238    while (data_len != 0 && buffer_offset >= data_len + sizeof(uint32_t)) {
239        EthPacketPtr packet;
240        packet = make_shared<EthPacketData>(data_len);
241        packet->length = data_len;
242        packet->simLength = data_len;
243        memcpy(packet->data, data, data_len);
244
245        assert(buffer_offset >= data_len + sizeof(uint32_t));
246        buffer_offset -= data_len + sizeof(uint32_t);
247        if (buffer_offset > 0) {
248            memmove(buffer, data + data_len, buffer_offset);
249            data_len = ntohl(*(uint32_t *)buffer);
250        } else
251            data_len = 0;
252
253        DPRINTF(Ethernet, "EtherTapStub input len=%d\n", packet->length);
254        DDUMP(EthernetData, packet->data, packet->length);
255        if (!interface->sendPacket(packet)) {
256            DPRINTF(Ethernet, "bus busy...buffer for retransmission\n");
257            packetBuffer.push(packet);
258            if (!txEvent.scheduled())
259                schedule(txEvent, curTick() + retryTime);
260        } else if (dump) {
261            dump->dump(packet);
262        }
263    }
264}
265
266void
267EtherTapStub::retransmit()
268{
269    if (packetBuffer.empty())
270        return;
271
272    EthPacketPtr packet = packetBuffer.front();
273    if (interface->sendPacket(packet)) {
274        if (dump)
275            dump->dump(packet);
276        DPRINTF(Ethernet, "EtherTapStub retransmit\n");
277        packetBuffer.front() = NULL;
278        packetBuffer.pop();
279    }
280
281    if (!packetBuffer.empty() && !txEvent.scheduled())
282        schedule(txEvent, curTick() + retryTime);
283}
284
285EtherInt*
286EtherTapStub::getEthPort(const std::string &if_name, int idx)
287{
288    if (if_name == "tap") {
289        if (interface->getPeer())
290            panic("Interface already connected to\n");
291        return interface;
292    }
293    return NULL;
294}
295
296
297//=====================================================================
298
299void
300EtherTapStub::serialize(CheckpointOut &cp) const
301{
302    SERIALIZE_SCALAR(socket);
303    SERIALIZE_SCALAR(buflen);
304    uint8_t *buffer = (uint8_t *)this->buffer;
305    SERIALIZE_ARRAY(buffer, buflen);
306    SERIALIZE_SCALAR(buffer_offset);
307    SERIALIZE_SCALAR(data_len);
308
309    bool tapevent_present = false;
310    if (event) {
311        tapevent_present = true;
312        SERIALIZE_SCALAR(tapevent_present);
313        event->serialize(cp);
314    }
315    else {
316        SERIALIZE_SCALAR(tapevent_present);
317    }
318}
319
320void
321EtherTapStub::unserialize(CheckpointIn &cp)
322{
323    UNSERIALIZE_SCALAR(socket);
324    UNSERIALIZE_SCALAR(buflen);
325    uint8_t *buffer = (uint8_t *)this->buffer;
326    UNSERIALIZE_ARRAY(buffer, buflen);
327    UNSERIALIZE_SCALAR(buffer_offset);
328    UNSERIALIZE_SCALAR(data_len);
329
330    bool tapevent_present;
331    UNSERIALIZE_SCALAR(tapevent_present);
332    if (tapevent_present) {
333        event = new TapEvent(this, socket, POLLIN|POLLERR);
334
335        event->unserialize(cp);
336
337        if (event->queued()) {
338            pollQueue.schedule(event);
339        }
340    }
341}
342
343//=====================================================================
344
345EtherTapStub *
346EtherTapStubParams::create()
347{
348    return new EtherTapStub(this);
349}
350