dist, dev: add an ethernet switch model

1 files changed, 256 insertions, 0 deletions

diff --git a/src/dev/net/etherswitch.cc b/src/dev/net/etherswitch.cc
new file mode 100644
index 000000000..02bbff65d
--- /dev/null
+++ b/src/dev/net/etherswitch.cc
@@ -0,0 +1,256 @@
+/*
+ * Copyright (c) 2014 The Regents of The University of Michigan
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met: redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer;
+ * redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution;
+ * neither the name of the copyright holders nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Authors: Anthony Gutierrez
+ *          Mohammad Alian
+ */
+
+/* @file
+ * Device model for an ethernet switch
+ */
+
+#include "dev/net/etherswitch.hh"
+
+#include "base/random.hh"
+#include "debug/EthernetAll.hh"
+
+using namespace std;
+
+EtherSwitch::EtherSwitch(const Params *p)
+    : EtherObject(p), ttl(p->time_to_live)
+{
+    for (int i = 0; i < p->port_interface_connection_count; ++i) {
+        std::string interfaceName = csprintf("%s.interface%d", name(), i);
+        Interface *interface = new Interface(interfaceName, this,
+                                        p->output_buffer_size, p->delay,
+                                        p->delay_var, p->fabric_speed);
+        interfaces.push_back(interface);
+    }
+}
+
+EtherSwitch::~EtherSwitch()
+{
+    for (auto it : interfaces)
+        delete it;
+
+    interfaces.clear();
+}
+
+EtherInt*
+EtherSwitch::getEthPort(const std::string &if_name, int idx)
+{
+    if (idx < 0 || idx >= interfaces.size())
+        return nullptr;
+
+    Interface *interface = interfaces.at(idx);
+    panic_if(interface->getPeer(), "interface already connected\n");
+
+    return interface;
+}
+
+EtherSwitch::Interface::Interface(const std::string &name,
+                                  EtherSwitch *etherSwitch,
+                                  uint64_t outputBufferSize, Tick delay,
+                                  Tick delay_var, double rate)
+    : EtherInt(name), ticksPerByte(rate), switchDelay(delay),
+      delayVar(delay_var), parent(etherSwitch),
+      outputFifo(outputBufferSize), txEvent(this)
+{
+}
+
+bool
+EtherSwitch::Interface::recvPacket(EthPacketPtr packet)
+{
+    Net::EthAddr destMacAddr(packet->data);
+    Net::EthAddr srcMacAddr(&packet->data[6]);
+
+    learnSenderAddr(srcMacAddr, this);
+    Interface *receiver = lookupDestPort(destMacAddr);
+
+    if (!receiver || destMacAddr.multicast() || destMacAddr.broadcast()) {
+        for (auto it : parent->interfaces)
+            if (it != this)
+                it->enqueue(packet);
+    } else {
+        DPRINTF(Ethernet, "sending packet from MAC %x on port "
+                "%s to MAC %x on port %s\n", uint64_t(srcMacAddr),
+                this->name(), uint64_t(destMacAddr), receiver->name());
+
+        receiver->enqueue(packet);
+    }
+    // At the output port, we either have buffer space (no drop) or
+    // don't (drop packet); in both cases packet is received on
+    // the interface successfully and there is no notion of busy
+    // interface here (as we don't have inputFifo)
+    return true;
+}
+
+void
+EtherSwitch::Interface::enqueue(EthPacketPtr packet)
+{
+    if (!outputFifo.push(packet)) {
+        // output buffer full, drop packet
+        DPRINTF(Ethernet, "output buffer full, drop packet\n");
+        return;
+    }
+
+    // assuming per-interface transmission events,
+    // if there was nothing in the Fifo before push the
+    // current packet, then we need to schedule an event at
+    // curTick + switchingDelay to send this packet out the external link
+    // otherwise, there is already a txEvent scheduled
+    if (!txEvent.scheduled()) {
+        parent->schedule(txEvent, curTick() + switchingDelay());
+    }
+}
+
+void
+EtherSwitch::Interface::transmit()
+{
+    // there should be something in the output queue
+    assert(!outputFifo.empty());
+
+    if (!sendPacket(outputFifo.front())) {
+        DPRINTF(Ethernet, "output port busy...retry later\n");
+        if (!txEvent.scheduled())
+            parent->schedule(txEvent, curTick() + retryTime);
+    } else {
+        DPRINTF(Ethernet, "packet sent: len=%d\n", outputFifo.front()->length);
+        outputFifo.pop();
+        // schedule an event to send the pkt at
+        // the head of queue, if there is any
+        if (!outputFifo.empty()) {
+            parent->schedule(txEvent, curTick() + switchingDelay());
+        }
+    }
+}
+
+Tick
+EtherSwitch::Interface::switchingDelay()
+{
+    Tick delay = (Tick)ceil(((double)outputFifo.front()->length
+                                     * ticksPerByte) + 1.0);
+    if (delayVar != 0)
+                delay += random_mt.random<Tick>(0, delayVar);
+    delay += switchDelay;
+    return delay;
+}
+
+EtherSwitch::Interface*
+EtherSwitch::Interface::lookupDestPort(Net::EthAddr destMacAddr)
+{
+    auto it = parent->forwardingTable.find(uint64_t(destMacAddr));
+
+    if (it == parent->forwardingTable.end()) {
+        DPRINTF(Ethernet, "no entry in forwaring table for MAC: "
+                "%x\n", uint64_t(destMacAddr));
+        return nullptr;
+    }
+
+    // check if this entry is valid based on TTL and lastUseTime
+    if ((curTick() - it->second.lastUseTime) > parent->ttl) {
+        // TTL for this mapping has been expired, so this item is not
+        // valide anymore, let's remove it from the map
+        parent->forwardingTable.erase(it);
+        return nullptr;
+    }
+
+    DPRINTF(Ethernet, "found entry for MAC address %x on port %s\n",
+            uint64_t(destMacAddr), it->second.interface->name());
+    return it->second.interface;
+}
+
+void
+EtherSwitch::Interface::learnSenderAddr(Net::EthAddr srcMacAddr,
+                                          Interface *sender)
+{
+    // learn the port for the sending MAC address
+    auto it = parent->forwardingTable.find(uint64_t(srcMacAddr));
+
+    // if the port for sender's MAC address is not cached,
+    // cache it now, otherwise just update lastUseTime time
+    if (it == parent->forwardingTable.end()) {
+        DPRINTF(Ethernet, "adding forwarding table entry for MAC "
+                " address %x on port %s\n", uint64_t(srcMacAddr),
+                sender->name());
+        EtherSwitch::SwitchTableEntry forwardingTableEntry;
+        forwardingTableEntry.interface = sender;
+        forwardingTableEntry.lastUseTime = curTick();
+        parent->forwardingTable.insert(std::make_pair(uint64_t(srcMacAddr),
+            forwardingTableEntry));
+    } else {
+        it->second.lastUseTime = curTick();
+    }
+}
+
+void
+EtherSwitch::serialize(CheckpointOut &cp) const
+{
+    for (auto it : interfaces)
+        it->serialize(it->name(), cp);
+}
+
+void
+EtherSwitch::unserialize(CheckpointIn &cp)
+{
+    for (auto it : interfaces)
+        it->unserialize(it->name(), cp);
+}
+
+void
+EtherSwitch::Interface::serialize(const std::string &base, CheckpointOut &cp)
+const
+{
+    bool event_scheduled = txEvent.scheduled();
+    paramOut(cp, base + ".event_scheduled", event_scheduled);
+    if (event_scheduled) {
+        Tick event_time = txEvent.when();
+        paramOut(cp, base + ".event_time", event_time);
+    }
+
+    outputFifo.serialize(base + "outputFifo", cp);
+}
+
+void
+EtherSwitch::Interface::unserialize(const std::string &base, CheckpointIn &cp)
+{
+    bool event_scheduled;
+    paramIn(cp, base + ".event_scheduled", event_scheduled);
+    if (event_scheduled) {
+        Tick event_time;
+        paramIn(cp, base + ".event_time", event_time);
+        parent->schedule(txEvent, event_time);
+    }
+
+    outputFifo.unserialize(base + "outputFifo", cp);
+}
+
+EtherSwitch *
+EtherSwitchParams::create()
+{
+    return new EtherSwitch(this);
+}