etherlink.cc revision 12087 
1/*
2 * Copyright (c) 2015 ARM Limited
3 * All rights reserved
4 *
5 * The license below extends only to copyright in the software and shall
6 * not be construed as granting a license to any other intellectual
7 * property including but not limited to intellectual property relating
8 * to a hardware implementation of the functionality of the software
9 * licensed hereunder.  You may use the software subject to the license
10 * terms below provided that you ensure that this notice is replicated
11 * unmodified and in its entirety in all distributions of the software,
12 * modified or unmodified, in source code or in binary form.
13 *
14 * Copyright (c) 2002-2005 The Regents of The University of Michigan
15 * All rights reserved.
16 *
17 * Redistribution and use in source and binary forms, with or without
18 * modification, are permitted provided that the following conditions are
19 * met: redistributions of source code must retain the above copyright
20 * notice, this list of conditions and the following disclaimer;
21 * redistributions in binary form must reproduce the above copyright
22 * notice, this list of conditions and the following disclaimer in the
23 * documentation and/or other materials provided with the distribution;
24 * neither the name of the copyright holders nor the names of its
25 * contributors may be used to endorse or promote products derived from
26 * this software without specific prior written permission.
27 *
28 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
29 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
30 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
31 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
32 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
33 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
34 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
35 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
36 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
37 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
38 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
39 *
40 * Authors: Nathan Binkert
41 *          Ron Dreslinski
42 */
43
44/* @file
45 * Device module for modelling a fixed bandwidth full duplex ethernet link
46 */
47
48#include "dev/net/etherlink.hh"
49
50#include <cmath>
51#include <deque>
52#include <string>
53#include <vector>
54
55#include "base/random.hh"
56#include "base/trace.hh"
57#include "debug/Ethernet.hh"
58#include "debug/EthernetData.hh"
59#include "dev/net/etherdump.hh"
60#include "dev/net/etherint.hh"
61#include "dev/net/etherpkt.hh"
62#include "params/EtherLink.hh"
63#include "sim/core.hh"
64#include "sim/serialize.hh"
65#include "sim/system.hh"
66
67using namespace std;
68
69EtherLink::EtherLink(const Params *p)
70    : EtherObject(p)
71{
72    link[0] = new Link(name() + ".link0", this, 0, p->speed,
73                       p->delay, p->delay_var, p->dump);
74    link[1] = new Link(name() + ".link1", this, 1, p->speed,
75                       p->delay, p->delay_var, p->dump);
76
77    interface[0] = new Interface(name() + ".int0", link[0], link[1]);
78    interface[1] = new Interface(name() + ".int1", link[1], link[0]);
79}
80
81
82EtherLink::~EtherLink()
83{
84    delete link[0];
85    delete link[1];
86
87    delete interface[0];
88    delete interface[1];
89}
90
91EtherInt*
92EtherLink::getEthPort(const std::string &if_name, int idx)
93{
94    Interface *i;
95    if (if_name == "int0")
96        i = interface[0];
97    else if (if_name == "int1")
98        i = interface[1];
99    else
100        return NULL;
101    if (i->getPeer())
102        panic("interface already connected to\n");
103
104    return i;
105}
106
107
108EtherLink::Interface::Interface(const string &name, Link *tx, Link *rx)
109    : EtherInt(name), txlink(tx)
110{
111    tx->setTxInt(this);
112    rx->setRxInt(this);
113}
114
115EtherLink::Link::Link(const string &name, EtherLink *p, int num,
116                      double rate, Tick delay, Tick delay_var, EtherDump *d)
117    : objName(name), parent(p), number(num), txint(NULL), rxint(NULL),
118      ticksPerByte(rate), linkDelay(delay), delayVar(delay_var), dump(d),
119      doneEvent([this]{ txDone(); }, name),
120      txQueueEvent([this]{ processTxQueue(); }, name)
121{ }
122
123void
124EtherLink::serialize(CheckpointOut &cp) const
125{
126    link[0]->serialize("link0", cp);
127    link[1]->serialize("link1", cp);
128}
129
130void
131EtherLink::unserialize(CheckpointIn &cp)
132{
133    link[0]->unserialize("link0", cp);
134    link[1]->unserialize("link1", cp);
135}
136
137void
138EtherLink::Link::txComplete(EthPacketPtr packet)
139{
140    DPRINTF(Ethernet, "packet received: len=%d\n", packet->length);
141    DDUMP(EthernetData, packet->data, packet->length);
142    rxint->sendPacket(packet);
143}
144
145void
146EtherLink::Link::txDone()
147{
148    if (dump)
149        dump->dump(packet);
150
151    if (linkDelay > 0) {
152        DPRINTF(Ethernet, "packet delayed: delay=%d\n", linkDelay);
153        txQueue.emplace_back(std::make_pair(curTick() + linkDelay, packet));
154        if (!txQueueEvent.scheduled())
155            parent->schedule(txQueueEvent, txQueue.front().first);
156    } else {
157        assert(txQueue.empty());
158        txComplete(packet);
159    }
160
161    packet = 0;
162    assert(!busy());
163
164    txint->sendDone();
165}
166
167void
168EtherLink::Link::processTxQueue()
169{
170    auto cur(txQueue.front());
171    txQueue.pop_front();
172
173    // Schedule a new event to process the next packet in the queue.
174    if (!txQueue.empty()) {
175        auto next(txQueue.front());
176        assert(next.first > curTick());
177        parent->schedule(txQueueEvent, next.first);
178    }
179
180    assert(cur.first == curTick());
181    txComplete(cur.second);
182}
183
184bool
185EtherLink::Link::transmit(EthPacketPtr pkt)
186{
187    if (busy()) {
188        DPRINTF(Ethernet, "packet not sent, link busy\n");
189        return false;
190    }
191
192    DPRINTF(Ethernet, "packet sent: len=%d\n", pkt->length);
193    DDUMP(EthernetData, pkt->data, pkt->length);
194
195    packet = pkt;
196    Tick delay = (Tick)ceil(((double)pkt->simLength * ticksPerByte) + 1.0);
197    if (delayVar != 0)
198        delay += random_mt.random<Tick>(0, delayVar);
199
200    DPRINTF(Ethernet, "scheduling packet: delay=%d, (rate=%f)\n",
201            delay, ticksPerByte);
202    parent->schedule(doneEvent, curTick() + delay);
203
204    return true;
205}
206
207void
208EtherLink::Link::serialize(const string &base, CheckpointOut &cp) const
209{
210    bool packet_exists = packet != nullptr;
211    paramOut(cp, base + ".packet_exists", packet_exists);
212    if (packet_exists)
213        packet->serialize(base + ".packet", cp);
214
215    bool event_scheduled = doneEvent.scheduled();
216    paramOut(cp, base + ".event_scheduled", event_scheduled);
217    if (event_scheduled) {
218        Tick event_time = doneEvent.when();
219        paramOut(cp, base + ".event_time", event_time);
220    }
221
222    const size_t tx_queue_size(txQueue.size());
223    paramOut(cp, base + ".tx_queue_size", tx_queue_size);
224    unsigned idx(0);
225    for (const auto &pe : txQueue) {
226        paramOut(cp, csprintf("%s.txQueue[%i].tick", base, idx), pe.first);
227        pe.second->serialize(csprintf("%s.txQueue[%i].packet", base, idx), cp);
228
229        ++idx;
230    }
231}
232
233void
234EtherLink::Link::unserialize(const string &base, CheckpointIn &cp)
235{
236    bool packet_exists;
237    paramIn(cp, base + ".packet_exists", packet_exists);
238    if (packet_exists) {
239        packet = make_shared<EthPacketData>();
240        packet->unserialize(base + ".packet", cp);
241    }
242
243    bool event_scheduled;
244    paramIn(cp, base + ".event_scheduled", event_scheduled);
245    if (event_scheduled) {
246        Tick event_time;
247        paramIn(cp, base + ".event_time", event_time);
248        parent->schedule(doneEvent, event_time);
249    }
250
251    size_t tx_queue_size;
252    if (optParamIn(cp, base + ".tx_queue_size", tx_queue_size)) {
253        for (size_t idx = 0; idx < tx_queue_size; ++idx) {
254            Tick tick;
255            EthPacketPtr delayed_packet = make_shared<EthPacketData>();
256
257            paramIn(cp, csprintf("%s.txQueue[%i].tick", base, idx), tick);
258            delayed_packet->unserialize(
259                csprintf("%s.txQueue[%i].packet", base, idx), cp);
260
261            fatal_if(!txQueue.empty() && txQueue.back().first > tick,
262                     "Invalid txQueue packet order in EtherLink!\n");
263            txQueue.emplace_back(std::make_pair(tick, delayed_packet));
264        }
265
266        if (!txQueue.empty())
267            parent->schedule(txQueueEvent, txQueue.front().first);
268    } else {
269        // We can't reliably convert in-flight packets from old
270        // checkpoints. In fact, gem5 hasn't been able to load these
271        // packets for at least two years before the format change.
272        warn("Old-style EtherLink serialization format detected, "
273             "in-flight packets may have been dropped.\n");
274    }
275}
276
277EtherLink *
278EtherLinkParams::create()
279{
280    return new EtherLink(this);
281}
282