dev/ethertap.cc

   1 /*
   2  * Copyright (c) 2003 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
  29 /* @file
  30  * Interface to connect a simulated ethernet device to the real world
  31  */
  32
  33 #if defined(__OpenBSD__)
  34 #include <sys/param.h>
  35 #endif
  36 #include <netinet/in.h>
  37
  38 #include <unistd.h>
  39
  40 #include <deque>
  41 #include <string>
  42
  43 #include "base/misc.hh"
  44 #include "base/pollevent.hh"
  45 #include "base/socket.hh"
  46 #include "base/trace.hh"
  47 #include "dev/etherdump.hh"
  48 #include "dev/etherint.hh"
  49 #include "dev/etherpkt.hh"
  50 #include "dev/ethertap.hh"
  51 #include "sim/builder.hh"
  52
  53 using namespace std;
  54
  55 /**
  56  */
  57 class TapListener
  58 {
  59   protected:
  60     /**
  61      */
  62     class Event : public PollEvent
  63     {
  64       protected:
  65         TapListener *listener;
  66
  67       public:
  68         Event(TapListener *l, int fd, int e)
  69             : PollEvent(fd, e), listener(l) {}
  70
  71         virtual void process(int revent) { listener->accept(); }
  72     };
  73
  74     friend class Event;
  75     Event *event;
  76
  77   protected:
  78     ListenSocket listener;
  79     EtherTap *tap;
  80     int port;
  81
  82   public:
  83     TapListener(EtherTap *t, int p)
  84         : event(NULL), tap(t), port(p) {}
  85     ~TapListener() { if (event) delete event; }
  86
  87     void accept();
  88     void listen();
  89 };
  90
  91 void
  92 TapListener::listen()
  93 {
  94     while (!listener.listen(port, true)) {
  95         DPRINTF(Ethernet, "TapListener(listen): Can't bind port %d\n", port);
  96         port++;
  97     }
  98
  99     ccprintf(cerr, "Listening for tap connection on port %d\n", port);
 100     event = new Event(this, listener.getfd(), POLLIN|POLLERR);
 101     pollQueue.schedule(event);
 102 }
 103
 104 void
 105 TapListener::accept()
 106 {
 107     if (!listener.islistening())
 108         panic("TapListener(accept): cannot accept if we're not listening!");
 109
 110     int sfd = listener.accept(true);
 111     if (sfd != -1)
 112         tap->attach(sfd);
 113 }
 114
 115 /**
 116  */
 117 class TapEvent : public PollEvent
 118 {
 119   protected:
 120     EtherTap *tap;
 121
 122   public:
 123     TapEvent(EtherTap *_tap, int fd, int e)
 124         : PollEvent(fd, e), tap(_tap) {}
 125     virtual void process(int revent) { tap->process(revent); }
 126 };
 127
 128 EtherTap::EtherTap(const string &name, EtherDump *d, int port, int bufsz)
 129     : EtherInt(name), event(NULL), socket(-1), buflen(bufsz), dump(d),
 130       txEvent(this)
 131 {
 132     buffer = new char[buflen];
 133     listener = new TapListener(this, port);
 134     listener->listen();
 135 }
 136
 137 EtherTap::~EtherTap()
 138 {
 139     if (event)
 140         delete event;
 141     if (buffer)
 142         delete [] buffer;
 143
 144     delete listener;
 145 }
 146
 147 void
 148 EtherTap::attach(int fd)
 149 {
 150     if (socket != -1)
 151         close(fd);
 152
 153     buffer_offset = 0;
 154     data_len = 0;
 155     socket = fd;
 156     DPRINTF(Ethernet, "EtherTap attached\n");
 157     event = new TapEvent(this, socket, POLLIN|POLLERR);
 158     pollQueue.schedule(event);
 159 }
 160
 161 void
 162 EtherTap::detach()
 163 {
 164     DPRINTF(Ethernet, "EtherTap detached\n");
 165     delete event;
 166     close(socket);
 167     socket = -1;
 168 }
 169
 170 bool
 171 EtherTap::recvPacket(PacketPtr packet)
 172 {
 173     if (dump)
 174         dump->dump(packet);
 175
 176     DPRINTF(Ethernet, "EtherTap output len=%d\n", packet->length);
 177     DDUMP(EthernetData, packet->data, packet->length);
 178     u_int32_t len = htonl(packet->length);
 179     write(socket, &len, sizeof(len));
 180     write(socket, packet->data, packet->length);
 181
 182     recvDone();
 183
 184     return true;
 185 }
 186
 187 void
 188 EtherTap::sendDone()
 189 {}
 190
 191 void
 192 EtherTap::process(int revent)
 193 {
 194     if (revent & POLLERR) {
 195         detach();
 196         return;
 197     }
 198
 199     char *data = buffer + sizeof(u_int32_t);
 200     if (!(revent & POLLIN))
 201         return;
 202
 203     if (buffer_offset < data_len + sizeof(u_int32_t)) {
 204         int len = read(socket, buffer + buffer_offset, buflen - buffer_offset);
 205         if (len == 0) {
 206             detach();
 207             return;
 208         }
 209
 210         buffer_offset += len;
 211
 212         if (data_len == 0)
 213             data_len = ntohl(*(u_int32_t *)buffer);
 214
 215         DPRINTF(Ethernet, "Received data from peer: len=%d buffer_offset=%d "
 216                 "data_len=%d\n", len, buffer_offset, data_len);
 217     }
 218
 219     while (data_len != 0 && buffer_offset >= data_len + sizeof(u_int32_t)) {
 220         PacketPtr packet;
 221         packet = new EtherPacket;
 222         packet->data = new uint8_t[data_len];
 223         packet->length = data_len;
 224         memcpy(packet->data, data, data_len);
 225
 226         buffer_offset -= data_len + sizeof(u_int32_t);
 227         assert(buffer_offset >= 0);
 228         if (buffer_offset > 0) {
 229             memmove(buffer, data + data_len, buffer_offset);
 230             data_len = ntohl(*(u_int32_t *)buffer);
 231         } else
 232             data_len = 0;
 233
 234         DPRINTF(Ethernet, "EtherTap input len=%d\n", packet->length);
 235         DDUMP(EthernetData, packet->data, packet->length);
 236         if (!sendPacket(packet)) {
 237             DPRINTF(Ethernet, "bus busy...buffer for retransmission\n");
 238             packetBuffer.push(packet);
 239             if (!txEvent.scheduled())
 240                 txEvent.schedule(curTick + 1000);
 241         } else if (dump)
 242             dump->dump(packet);
 243     }
 244 }
 245
 246 void
 247 EtherTap::retransmit()
 248 {
 249     if (packetBuffer.empty())
 250         return;
 251
 252     PacketPtr packet = packetBuffer.front();
 253     if (sendPacket(packet)) {
 254         if (dump)
 255             dump->dump(packet);
 256         DPRINTF(Ethernet, "EtherTap retransmit\n");
 257         packetBuffer.front() = NULL;
 258         packetBuffer.pop();
 259     }
 260
 261     if (!packetBuffer.empty() && !txEvent.scheduled())
 262         txEvent.schedule(curTick + 1000);
 263 }
 264
 265 BEGIN_DECLARE_SIM_OBJECT_PARAMS(EtherTap)
 266
 267     SimObjectParam<EtherInt *> peer;
 268     SimObjectParam<EtherDump *> packet_dump;
 269     Param<uint16_t> port;
 270     Param<uint16_t> bufsz;
 271
 272 END_DECLARE_SIM_OBJECT_PARAMS(EtherTap)
 273
 274 BEGIN_INIT_SIM_OBJECT_PARAMS(EtherTap)
 275
 276     INIT_PARAM_DFLT(peer, "peer interface", NULL),
 277     INIT_PARAM_DFLT(packet_dump, "object to dump network packets to", NULL),
 278     INIT_PARAM_DFLT(port, "tap port", 3500),
 279     INIT_PARAM_DFLT(bufsz, "tap buffer size", 10000)
 280
 281 END_INIT_SIM_OBJECT_PARAMS(EtherTap)
 282
 283
 284 CREATE_SIM_OBJECT(EtherTap)
 285 {
 286     EtherTap *tap = new EtherTap(getInstanceName(), packet_dump, port, bufsz);
 287
 288     if (peer) {
 289         tap->setPeer(peer);
 290         peer->setPeer(tap);
 291     }
 292
 293     return tap;
 294 }
 295
 296 REGISTER_SIM_OBJECT("EtherTap", EtherTap)