src/dev/ethertap.cc

   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 "params/EtherTap.hh"
  54
  55 using namespace std;
  56
  57 /**
  58  */
  59 class 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
  93 void
  94 TapListener::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
 106 void
 107 TapListener::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  */
 119 class 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
 130 EtherTap::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
 139 EtherTap::~EtherTap()
 140 {
 141     if (event)
 142         delete event;
 143     if (buffer)
 144         delete [] buffer;
 145
 146     delete listener;
 147 }
 148
 149 void
 150 EtherTap::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
 163 void
 164 EtherTap::detach()
 165 {
 166     DPRINTF(Ethernet, "EtherTap detached\n");
 167     delete event;
 168     event = 0;
 169     close(socket);
 170     socket = -1;
 171 }
 172
 173 bool
 174 EtherTap::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     uint32_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
 190 void
 191 EtherTap::sendDone()
 192 {}
 193
 194 void
 195 EtherTap::process(int revent)
 196 {
 197     if (revent & POLLERR) {
 198         detach();
 199         return;
 200     }
 201
 202     char *data = buffer + sizeof(uint32_t);
 203     if (!(revent & POLLIN))
 204         return;
 205
 206     if (buffer_offset < data_len + sizeof(uint32_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(*(uint32_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(uint32_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(uint32_t);
 229         assert(buffer_offset >= 0);
 230         if (buffer_offset > 0) {
 231             memmove(buffer, data + data_len, buffer_offset);
 232             data_len = ntohl(*(uint32_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
 249 void
 250 EtherTap::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
 270 void
 271 EtherTap::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
 291 void
 292 EtherTap::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
 316 EtherTap *
 317 EtherTapParams::create()
 318 {
 319     EtherTap *tap = new EtherTap(name, dump, port, bufsz);
 320
 321     if (peer) {
 322         tap->setPeer(peer);
 323         peer->setPeer(tap);
 324     }
 325
 326     return tap;
 327 }