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 #include <unistd.h>
  40
  41 #include <deque>
  42 #include <string>
  43
  44 #include "base/misc.hh"
  45 #include "base/pollevent.hh"
  46 #include "base/socket.hh"
  47 #include "base/trace.hh"
  48 #include "debug/Ethernet.hh"
  49 #include "debug/EthernetData.hh"
  50 #include "dev/etherdump.hh"
  51 #include "dev/etherint.hh"
  52 #include "dev/etherpkt.hh"
  53 #include "dev/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 Params *p)
 131     : EtherObject(p), event(NULL), socket(-1), buflen(p->bufsz), dump(p->dump),
 132       interface(NULL), txEvent(this)
 133 {
 134     if (ListenSocket::allDisabled())
 135         fatal("All listeners are disabled! EtherTap can't work!");
 136
 137     buffer = new char[buflen];
 138     listener = new TapListener(this, p->port);
 139     listener->listen();
 140     interface = new EtherTapInt(name() + ".interface", this);
 141 }
 142
 143 EtherTap::~EtherTap()
 144 {
 145     if (event)
 146         delete event;
 147     if (buffer)
 148         delete [] buffer;
 149
 150     delete listener;
 151 }
 152
 153 void
 154 EtherTap::attach(int fd)
 155 {
 156     if (socket != -1)
 157         close(fd);
 158
 159     buffer_offset = 0;
 160     data_len = 0;
 161     socket = fd;
 162     DPRINTF(Ethernet, "EtherTap attached\n");
 163     event = new TapEvent(this, socket, POLLIN|POLLERR);
 164     pollQueue.schedule(event);
 165 }
 166
 167 void
 168 EtherTap::detach()
 169 {
 170     DPRINTF(Ethernet, "EtherTap detached\n");
 171     delete event;
 172     event = 0;
 173     close(socket);
 174     socket = -1;
 175 }
 176
 177 bool
 178 EtherTap::recvPacket(EthPacketPtr packet)
 179 {
 180     if (dump)
 181         dump->dump(packet);
 182
 183     DPRINTF(Ethernet, "EtherTap output len=%d\n", packet->length);
 184     DDUMP(EthernetData, packet->data, packet->length);
 185     uint32_t len = htonl(packet->length);
 186     ssize_t ret = write(socket, &len, sizeof(len));
 187     if (ret != sizeof(len))
 188         return false;
 189     ret = write(socket, packet->data, packet->length);
 190     if (ret != packet->length)
 191         return false;
 192
 193     interface->recvDone();
 194
 195     return true;
 196 }
 197
 198 void
 199 EtherTap::sendDone()
 200 {}
 201
 202 void
 203 EtherTap::process(int revent)
 204 {
 205     if (revent & POLLERR) {
 206         detach();
 207         return;
 208     }
 209
 210     char *data = buffer + sizeof(uint32_t);
 211     if (!(revent & POLLIN))
 212         return;
 213
 214     if (buffer_offset < data_len + sizeof(uint32_t)) {
 215         int len = read(socket, buffer + buffer_offset, buflen - buffer_offset);
 216         if (len == 0) {
 217             detach();
 218             return;
 219         }
 220
 221         buffer_offset += len;
 222
 223         if (data_len == 0)
 224             data_len = ntohl(*(uint32_t *)buffer);
 225
 226         DPRINTF(Ethernet, "Received data from peer: len=%d buffer_offset=%d "
 227                 "data_len=%d\n", len, buffer_offset, data_len);
 228     }
 229
 230     while (data_len != 0 && buffer_offset >= data_len + sizeof(uint32_t)) {
 231         EthPacketPtr packet;
 232         packet = new EthPacketData(data_len);
 233         packet->length = data_len;
 234         memcpy(packet->data, data, data_len);
 235
 236         buffer_offset -= data_len + sizeof(uint32_t);
 237         assert(buffer_offset >= 0);
 238         if (buffer_offset > 0) {
 239             memmove(buffer, data + data_len, buffer_offset);
 240             data_len = ntohl(*(uint32_t *)buffer);
 241         } else
 242             data_len = 0;
 243
 244         DPRINTF(Ethernet, "EtherTap input len=%d\n", packet->length);
 245         DDUMP(EthernetData, packet->data, packet->length);
 246         if (!interface->sendPacket(packet)) {
 247             DPRINTF(Ethernet, "bus busy...buffer for retransmission\n");
 248             packetBuffer.push(packet);
 249             if (!txEvent.scheduled())
 250                 schedule(txEvent, curTick() + retryTime);
 251         } else if (dump) {
 252             dump->dump(packet);
 253         }
 254     }
 255 }
 256
 257 void
 258 EtherTap::retransmit()
 259 {
 260     if (packetBuffer.empty())
 261         return;
 262
 263     EthPacketPtr packet = packetBuffer.front();
 264     if (interface->sendPacket(packet)) {
 265         if (dump)
 266             dump->dump(packet);
 267         DPRINTF(Ethernet, "EtherTap retransmit\n");
 268         packetBuffer.front() = NULL;
 269         packetBuffer.pop();
 270     }
 271
 272     if (!packetBuffer.empty() && !txEvent.scheduled())
 273         schedule(txEvent, curTick() + retryTime);
 274 }
 275
 276 EtherInt*
 277 EtherTap::getEthPort(const std::string &if_name, int idx)
 278 {
 279     if (if_name == "tap") {
 280         if (interface->getPeer())
 281             panic("Interface already connected to\n");
 282         return interface;
 283     }
 284     return NULL;
 285 }
 286
 287
 288 //=====================================================================
 289
 290 void
 291 EtherTap::serialize(ostream &os)
 292 {
 293     SERIALIZE_SCALAR(socket);
 294     SERIALIZE_SCALAR(buflen);
 295     uint8_t *buffer = (uint8_t *)this->buffer;
 296     SERIALIZE_ARRAY(buffer, buflen);
 297     SERIALIZE_SCALAR(buffer_offset);
 298     SERIALIZE_SCALAR(data_len);
 299
 300     bool tapevent_present = false;
 301     if (event) {
 302         tapevent_present = true;
 303         SERIALIZE_SCALAR(tapevent_present);
 304         event->serialize(os);
 305     }
 306     else {
 307         SERIALIZE_SCALAR(tapevent_present);
 308     }
 309 }
 310
 311 void
 312 EtherTap::unserialize(Checkpoint *cp, const std::string &section)
 313 {
 314     UNSERIALIZE_SCALAR(socket);
 315     UNSERIALIZE_SCALAR(buflen);
 316     uint8_t *buffer = (uint8_t *)this->buffer;
 317     UNSERIALIZE_ARRAY(buffer, buflen);
 318     UNSERIALIZE_SCALAR(buffer_offset);
 319     UNSERIALIZE_SCALAR(data_len);
 320
 321     bool tapevent_present;
 322     UNSERIALIZE_SCALAR(tapevent_present);
 323     if (tapevent_present) {
 324         event = new TapEvent(this, socket, POLLIN|POLLERR);
 325
 326         event->unserialize(cp,section);
 327
 328         if (event->queued()) {
 329             pollQueue.schedule(event);
 330         }
 331     }
 332 }
 333
 334 //=====================================================================
 335
 336 EtherTap *
 337 EtherTapParams::create()
 338 {
 339     return new EtherTap(this);
 340 }