ethertap.cc revision 2665 
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#if defined(__OpenBSD__) || defined(__APPLE__)
36#include <sys/param.h>
37#endif
38#include <netinet/in.h>
39
40#include <unistd.h>
41
42#include <deque>
43#include <string>
44
45#include "base/misc.hh"
46#include "base/pollevent.hh"
47#include "base/socket.hh"
48#include "base/trace.hh"
49#include "dev/etherdump.hh"
50#include "dev/etherint.hh"
51#include "dev/etherpkt.hh"
52#include "dev/ethertap.hh"
53#include "sim/builder.hh"
54
55using namespace std;
56
57/**
58 */
59class TapListener
60{
61  protected:
62    /**
63     */
64    class Event : public PollEvent
65    {
66      protected:
67        TapListener *listener;
68
69      public:
70        Event(TapListener *l, int fd, int e)
71            : PollEvent(fd, e), listener(l) {}
72
73        virtual void process(int revent) { listener->accept(); }
74    };
75
76    friend class Event;
77    Event *event;
78
79  protected:
80    ListenSocket listener;
81    EtherTap *tap;
82    int port;
83
84  public:
85    TapListener(EtherTap *t, int p)
86        : event(NULL), tap(t), port(p) {}
87    ~TapListener() { if (event) delete event; }
88
89    void accept();
90    void listen();
91};
92
93void
94TapListener::listen()
95{
96    while (!listener.listen(port, true)) {
97        DPRINTF(Ethernet, "TapListener(listen): Can't bind port %d\n", port);
98        port++;
99    }
100
101    ccprintf(cerr, "Listening for tap connection on port %d\n", port);
102    event = new Event(this, listener.getfd(), POLLIN|POLLERR);
103    pollQueue.schedule(event);
104}
105
106void
107TapListener::accept()
108{
109    if (!listener.islistening())
110        panic("TapListener(accept): cannot accept if we're not listening!");
111
112    int sfd = listener.accept(true);
113    if (sfd != -1)
114        tap->attach(sfd);
115}
116
117/**
118 */
119class TapEvent : public PollEvent
120{
121  protected:
122    EtherTap *tap;
123
124  public:
125    TapEvent(EtherTap *_tap, int fd, int e)
126        : PollEvent(fd, e), tap(_tap) {}
127    virtual void process(int revent) { tap->process(revent); }
128};
129
130EtherTap::EtherTap(const string &name, EtherDump *d, int port, int bufsz)
131    : EtherInt(name), event(NULL), socket(-1), buflen(bufsz), dump(d),
132      txEvent(this)
133{
134    buffer = new char[buflen];
135    listener = new TapListener(this, port);
136    listener->listen();
137}
138
139EtherTap::~EtherTap()
140{
141    if (event)
142        delete event;
143    if (buffer)
144        delete [] buffer;
145
146    delete listener;
147}
148
149void
150EtherTap::attach(int fd)
151{
152    if (socket != -1)
153        close(fd);
154
155    buffer_offset = 0;
156    data_len = 0;
157    socket = fd;
158    DPRINTF(Ethernet, "EtherTap attached\n");
159    event = new TapEvent(this, socket, POLLIN|POLLERR);
160    pollQueue.schedule(event);
161}
162
163void
164EtherTap::detach()
165{
166    DPRINTF(Ethernet, "EtherTap detached\n");
167    delete event;
168    event = 0;
169    close(socket);
170    socket = -1;
171}
172
173bool
174EtherTap::recvPacket(EthPacketPtr packet)
175{
176    if (dump)
177        dump->dump(packet);
178
179    DPRINTF(Ethernet, "EtherTap output len=%d\n", packet->length);
180    DDUMP(EthernetData, packet->data, packet->length);
181    u_int32_t len = htonl(packet->length);
182    write(socket, &len, sizeof(len));
183    write(socket, packet->data, packet->length);
184
185    recvDone();
186
187    return true;
188}
189
190void
191EtherTap::sendDone()
192{}
193
194void
195EtherTap::process(int revent)
196{
197    if (revent & POLLERR) {
198        detach();
199        return;
200    }
201
202    char *data = buffer + sizeof(u_int32_t);
203    if (!(revent & POLLIN))
204        return;
205
206    if (buffer_offset < data_len + sizeof(u_int32_t)) {
207        int len = read(socket, buffer + buffer_offset, buflen - buffer_offset);
208        if (len == 0) {
209            detach();
210            return;
211        }
212
213        buffer_offset += len;
214
215        if (data_len == 0)
216            data_len = ntohl(*(u_int32_t *)buffer);
217
218        DPRINTF(Ethernet, "Received data from peer: len=%d buffer_offset=%d "
219                "data_len=%d\n", len, buffer_offset, data_len);
220    }
221
222    while (data_len != 0 && buffer_offset >= data_len + sizeof(u_int32_t)) {
223        EthPacketPtr packet;
224        packet = new EthPacketData(data_len);
225        packet->length = data_len;
226        memcpy(packet->data, data, data_len);
227
228        buffer_offset -= data_len + sizeof(u_int32_t);
229        assert(buffer_offset >= 0);
230        if (buffer_offset > 0) {
231            memmove(buffer, data + data_len, buffer_offset);
232            data_len = ntohl(*(u_int32_t *)buffer);
233        } else
234            data_len = 0;
235
236        DPRINTF(Ethernet, "EtherTap input len=%d\n", packet->length);
237        DDUMP(EthernetData, packet->data, packet->length);
238        if (!sendPacket(packet)) {
239            DPRINTF(Ethernet, "bus busy...buffer for retransmission\n");
240            packetBuffer.push(packet);
241            if (!txEvent.scheduled())
242                txEvent.schedule(curTick + retryTime);
243        } else if (dump) {
244            dump->dump(packet);
245        }
246    }
247}
248
249void
250EtherTap::retransmit()
251{
252    if (packetBuffer.empty())
253        return;
254
255    EthPacketPtr packet = packetBuffer.front();
256    if (sendPacket(packet)) {
257        if (dump)
258            dump->dump(packet);
259        DPRINTF(Ethernet, "EtherTap retransmit\n");
260        packetBuffer.front() = NULL;
261        packetBuffer.pop();
262    }
263
264    if (!packetBuffer.empty() && !txEvent.scheduled())
265        txEvent.schedule(curTick + retryTime);
266}
267
268//=====================================================================
269
270void
271EtherTap::serialize(ostream &os)
272{
273    SERIALIZE_SCALAR(socket);
274    SERIALIZE_SCALAR(buflen);
275    uint8_t *buffer = (uint8_t *)this->buffer;
276    SERIALIZE_ARRAY(buffer, buflen);
277    SERIALIZE_SCALAR(buffer_offset);
278    SERIALIZE_SCALAR(data_len);
279
280    bool tapevent_present = false;
281    if (event) {
282        tapevent_present = true;
283        SERIALIZE_SCALAR(tapevent_present);
284        event->serialize(os);
285    }
286    else {
287        SERIALIZE_SCALAR(tapevent_present);
288    }
289}
290
291void
292EtherTap::unserialize(Checkpoint *cp, const std::string &section)
293{
294    UNSERIALIZE_SCALAR(socket);
295    UNSERIALIZE_SCALAR(buflen);
296    uint8_t *buffer = (uint8_t *)this->buffer;
297    UNSERIALIZE_ARRAY(buffer, buflen);
298    UNSERIALIZE_SCALAR(buffer_offset);
299    UNSERIALIZE_SCALAR(data_len);
300
301    bool tapevent_present;
302    UNSERIALIZE_SCALAR(tapevent_present);
303    if (tapevent_present) {
304        event = new TapEvent(this, socket, POLLIN|POLLERR);
305
306        event->unserialize(cp,section);
307
308        if (event->queued()) {
309            pollQueue.schedule(event);
310        }
311    }
312}
313
314//=====================================================================
315
316BEGIN_DECLARE_SIM_OBJECT_PARAMS(EtherTap)
317
318    SimObjectParam<EtherInt *> peer;
319    SimObjectParam<EtherDump *> dump;
320    Param<unsigned> port;
321    Param<unsigned> bufsz;
322
323END_DECLARE_SIM_OBJECT_PARAMS(EtherTap)
324
325BEGIN_INIT_SIM_OBJECT_PARAMS(EtherTap)
326
327    INIT_PARAM_DFLT(peer, "peer interface", NULL),
328    INIT_PARAM_DFLT(dump, "object to dump network packets to", NULL),
329    INIT_PARAM_DFLT(port, "tap port", 3500),
330    INIT_PARAM_DFLT(bufsz, "tap buffer size", 10000)
331
332END_INIT_SIM_OBJECT_PARAMS(EtherTap)
333
334
335CREATE_SIM_OBJECT(EtherTap)
336{
337    EtherTap *tap = new EtherTap(getInstanceName(), dump, port, bufsz);
338
339    if (peer) {
340        tap->setPeer(peer);
341        peer->setPeer(tap);
342    }
343
344    return tap;
345}
346
347REGISTER_SIM_OBJECT("EtherTap", EtherTap)
348