1 files changed, 286 insertions, 0 deletions
diff --git a/src/VBox/NetworkServices/Dhcpd/DHCPD.cpp b/src/VBox/NetworkServices/Dhcpd/DHCPD.cpp
new file mode 100644
index 00000000..5ded7b38
--- /dev/null
+++ b/src/VBox/NetworkServices/Dhcpd/DHCPD.cpp
@@ -0,0 +1,286 @@
+/* $Id: DHCPD.cpp $ */
+/** @file
+ * DHCP server - protocol logic
+ */
+
+/*
+ * Copyright (C) 2017-2019 Oracle Corporation
+ *
+ * This file is part of VirtualBox Open Source Edition (OSE), as
+ * available from http://www.virtualbox.org. This file is free software;
+ * you can redistribute it and/or modify it under the terms of the GNU
+ * General Public License (GPL) as published by the Free Software
+ * Foundation, in version 2 as it comes in the "COPYING" file of the
+ * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
+ * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
+ */
+
+#include "DHCPD.h"
+#include "DhcpOptions.h"
+
+#include <iprt/path.h>
+
+
+DHCPD::DHCPD()
+  : m_pConfig(NULL), m_db()
+{
+}
+
+
+int DHCPD::init(const Config *pConfig)
+{
+    int rc;
+
+    if (m_pConfig != NULL)
+        return VERR_INVALID_STATE;
+
+    /* leases file name */
+    m_strLeasesFileName = pConfig->getHome();
+    m_strLeasesFileName += RTPATH_DELIMITER;
+    m_strLeasesFileName += pConfig->getBaseName();
+    m_strLeasesFileName += "-Dhcpd.leases";
+
+    rc = m_db.init(pConfig);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    loadLeases();
+
+    m_pConfig = pConfig;
+    return VINF_SUCCESS;
+}
+
+
+void DHCPD::loadLeases()
+{
+    m_db.loadLeases(m_strLeasesFileName);
+}
+
+
+void DHCPD::saveLeases()
+{
+    m_db.expire();
+    m_db.writeLeases(m_strLeasesFileName);
+}
+
+
+DhcpServerMessage *DHCPD::process(DhcpClientMessage &req)
+{
+    DhcpServerMessage *reply = NULL;
+
+    req.dump();
+
+    OptServerId sid(req);
+    if (sid.present() && sid.value().u != m_pConfig->getIPv4Address().u)
+    {
+        if (req.broadcasted() && req.messageType() == RTNET_DHCP_MT_REQUEST)
+            m_db.cancelOffer(req);
+
+        return NULL;
+    }
+
+    switch (req.messageType())
+    {
+        /*
+         * Requests that require server's reply.
+         */
+        case RTNET_DHCP_MT_DISCOVER:
+            reply = doDiscover(req);
+            break;
+
+        case RTNET_DHCP_MT_REQUEST:
+            reply = doRequest(req);
+            break;
+
+        case RTNET_DHCP_MT_INFORM:
+            reply = doInform(req);
+            break;
+
+        /*
+         * Requests that don't have a reply.
+         */
+        case RTNET_DHCP_MT_DECLINE:
+            doDecline(req);
+            break;
+
+        case RTNET_DHCP_MT_RELEASE:
+            doRelease(req);
+            break;
+
+        /*
+         * Unexpected or unknown message types.
+         */
+        case RTNET_DHCP_MT_OFFER: /* FALLTHROUGH */
+        case RTNET_DHCP_MT_ACK:   /* FALLTHROUGH */
+        case RTNET_DHCP_MT_NAC:   /* FALLTHROUGH */
+        default:
+            break;
+    }
+
+    return reply;
+}
+
+
+DhcpServerMessage *DHCPD::createMessage(int type, DhcpClientMessage &req)
+{
+    return new DhcpServerMessage(req, type, m_pConfig->getIPv4Address());
+}
+
+
+DhcpServerMessage *DHCPD::doDiscover(DhcpClientMessage &req)
+{
+    /*
+     * XXX: TODO: Windows iSCSI initiator sends DHCPDISCOVER first and
+     * it has ciaddr filled.  Shouldn't let it screw up the normal
+     * lease we already have for that client, but we should probably
+     * reply with a pro-forma offer.
+     */
+    if (req.ciaddr().u != 0)
+        return NULL;
+
+    Binding *b = m_db.allocateBinding(req);
+    if (b == NULL)
+        return NULL;
+
+
+    std::unique_ptr<DhcpServerMessage> reply;
+
+    bool fRapidCommit = OptRapidCommit(req).present();
+    if (!fRapidCommit)
+    {
+        reply.reset(createMessage(RTNET_DHCP_MT_OFFER, req));
+
+        if (b->state() < Binding::OFFERED)
+            b->setState(Binding::OFFERED);
+
+        /* use small lease time internally to quickly free unclaimed offers? */
+    }
+    else
+    {
+        reply.reset(createMessage(RTNET_DHCP_MT_ACK, req));
+        reply->addOption(OptRapidCommit(true));
+
+        b->setState(Binding::ACKED);
+        saveLeases();
+    }
+
+    reply->setYiaddr(b->addr());
+    reply->addOption(OptLeaseTime(b->leaseTime()));
+
+
+    OptParameterRequest optlist(req);
+    reply->addOptions(m_pConfig->getOptions(optlist, req.clientId()));
+
+    // reply->maybeUnicast(req); /* XXX: we reject ciaddr != 0 above */
+    return reply.release();
+}
+
+
+DhcpServerMessage *DHCPD::doRequest(DhcpClientMessage &req)
+{
+    OptRequestedAddress reqAddr(req);
+    if (req.ciaddr().u != 0 && reqAddr.present() && reqAddr.value().u != req.ciaddr().u)
+    {
+        std::unique_ptr<DhcpServerMessage> nak (
+            createMessage(RTNET_DHCP_MT_NAC, req)
+        );
+        nak->addOption(OptMessage("Requested address does not match ciaddr"));
+        return nak.release();
+    }
+
+
+    Binding *b = m_db.allocateBinding(req);
+    if (b == NULL)
+    {
+        return createMessage(RTNET_DHCP_MT_NAC, req);
+    }
+
+
+    std::unique_ptr<DhcpServerMessage> ack (
+        createMessage(RTNET_DHCP_MT_ACK, req)
+    );
+
+    b->setState(Binding::ACKED);
+    saveLeases();
+
+    ack->setYiaddr(b->addr());
+    ack->addOption(OptLeaseTime(b->leaseTime()));
+
+    OptParameterRequest optlist(req);
+    ack->addOptions(m_pConfig->getOptions(optlist, req.clientId()));
+
+    ack->addOption(OptMessage("Ok, ok, here it is"));
+
+    ack->maybeUnicast(req);
+    return ack.release();
+}
+
+
+/*
+ * 4.3.5 DHCPINFORM message
+ *
+ *    The server responds to a DHCPINFORM message by sending a DHCPACK
+ *    message directly to the address given in the 'ciaddr' field of the
+ *    DHCPINFORM message.  The server MUST NOT send a lease expiration time
+ *    to the client and SHOULD NOT fill in 'yiaddr'.  The server includes
+ *    other parameters in the DHCPACK message as defined in section 4.3.1.
+ */
+DhcpServerMessage *DHCPD::doInform(DhcpClientMessage &req)
+{
+    if (req.ciaddr().u == 0)
+        return NULL;
+
+    const OptParameterRequest params(req);
+    if (!params.present())
+        return NULL;
+
+    optmap_t info(m_pConfig->getOptions(params, req.clientId()));
+    if (info.empty())
+        return NULL;
+
+    std::unique_ptr<DhcpServerMessage> ack (
+        createMessage(RTNET_DHCP_MT_ACK, req)
+    );
+
+    ack->addOptions(info);
+
+    ack->maybeUnicast(req);
+    return ack.release();
+}
+
+
+/*
+ * 4.3.3 DHCPDECLINE message
+ *
+ *    If the server receives a DHCPDECLINE message, the client has
+ *    discovered through some other means that the suggested network
+ *    address is already in use.  The server MUST mark the network address
+ *    as not available and SHOULD notify the local system administrator of
+ *    a possible configuration problem.
+ */
+DhcpServerMessage *DHCPD::doDecline(DhcpClientMessage &req)
+{
+    RT_NOREF(req);
+    return NULL;
+}
+
+
+/*
+ * 4.3.4 DHCPRELEASE message
+ *
+ *    Upon receipt of a DHCPRELEASE message, the server marks the network
+ *    address as not allocated.  The server SHOULD retain a record of the
+ *    client's initialization parameters for possible reuse in response to
+ *    subsequent requests from the client.
+ */
+DhcpServerMessage *DHCPD::doRelease(DhcpClientMessage &req)
+{
+    if (req.ciaddr().u == 0)
+        return NULL;
+
+    bool released = m_db.releaseBinding(req);
+    if (released)
+        saveLeases();
+
+    return NULL;
+}