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
  54 using namespace std;
  55
  56 /**
  57  */
  58 class TapListener
  59 {
  60   protected:
  61     /**
  62      */
  63     class Event : public PollEvent
  64     {
  65       protected:
  66         TapListener *listener;
  67
  68       public:
  69         Event(TapListener *l, int fd, int e)
  70             : PollEvent(fd, e), listener(l) {}
  71
  72         virtual void process(int revent) { listener->accept(); }
  73     };
  74
  75     friend class Event;
  76     Event *event;
  77
  78   protected:
  79     ListenSocket listener;
  80     EtherTap *tap;
  81     int port;
  82
  83   public:
  84     TapListener(EtherTap *t, int p)
  85         : event(NULL), tap(t), port(p) {}
  86     ~TapListener() { if (event) delete event; }
  87
  88     void accept();
  89     void listen();
  90 };
  91
  92 void
  93 TapListener::listen()
  94 {
  95     while (!listener.listen(port, true)) {
  96         DPRINTF(Ethernet, "TapListener(listen): Can't bind port %d\n", port);
  97         port++;
  98     }
  99
 100     ccprintf(cerr, "Listening for tap connection on port %d\n", port);
 101     event = new Event(this, listener.getfd(), POLLIN|POLLERR);
 102     pollQueue.schedule(event);
 103 }
 104
 105 void
 106 TapListener::accept()
 107 {
 108     if (!listener.islistening())
 109         panic("TapListener(accept): cannot accept if we're not listening!");
 110
 111     int sfd = listener.accept(true);
 112     if (sfd != -1)
 113         tap->attach(sfd);
 114 }
 115
 116 /**
 117  */
 118 class TapEvent : public PollEvent
 119 {
 120   protected:
 121     EtherTap *tap;
 122
 123   public:
 124     TapEvent(EtherTap *_tap, int fd, int e)
 125         : PollEvent(fd, e), tap(_tap) {}
 126     virtual void process(int revent) { tap->process(revent); }
 127 };
 128
 129 EtherTap::EtherTap(const Params *p)
 130     : EtherObject(p), event(NULL), socket(-1), buflen(p->bufsz), dump(p->dump),
 131       interface(NULL), txEvent(this)
 132 {
 133     buffer = new char[buflen];
 134     listener = new TapListener(this, p->port);
 135     listener->listen();
 136     interface = new EtherTapInt(name() + ".interface", this);
 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     interface->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 (!interface->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 (interface->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 EtherInt*
 269 EtherTap::getEthPort(const std::string &if_name, int idx)
 270 {
 271     if (if_name == "tap") {
 272         if (interface->getPeer())
 273             panic("Interface already connected to\n");
 274         return interface;
 275     }
 276     return NULL;
 277 }
 278
 279
 280 //=====================================================================
 281
 282 void
 283 EtherTap::serialize(ostream &os)
 284 {
 285     SERIALIZE_SCALAR(socket);
 286     SERIALIZE_SCALAR(buflen);
 287     uint8_t *buffer = (uint8_t *)this->buffer;
 288     SERIALIZE_ARRAY(buffer, buflen);
 289     SERIALIZE_SCALAR(buffer_offset);
 290     SERIALIZE_SCALAR(data_len);
 291
 292     bool tapevent_present = false;
 293     if (event) {
 294         tapevent_present = true;
 295         SERIALIZE_SCALAR(tapevent_present);
 296         event->serialize(os);
 297     }
 298     else {
 299         SERIALIZE_SCALAR(tapevent_present);
 300     }
 301 }
 302
 303 void
 304 EtherTap::unserialize(Checkpoint *cp, const std::string &section)
 305 {
 306     UNSERIALIZE_SCALAR(socket);
 307     UNSERIALIZE_SCALAR(buflen);
 308     uint8_t *buffer = (uint8_t *)this->buffer;
 309     UNSERIALIZE_ARRAY(buffer, buflen);
 310     UNSERIALIZE_SCALAR(buffer_offset);
 311     UNSERIALIZE_SCALAR(data_len);
 312
 313     bool tapevent_present;
 314     UNSERIALIZE_SCALAR(tapevent_present);
 315     if (tapevent_present) {
 316         event = new TapEvent(this, socket, POLLIN|POLLERR);
 317
 318         event->unserialize(cp,section);
 319
 320         if (event->queued()) {
 321             pollQueue.schedule(event);
 322         }
 323     }
 324 }
 325
 326 //=====================================================================
 327
 328 EtherTap *
 329 EtherTapParams::create()
 330 {
 331     return new EtherTap(this);
 332 }