Filter.cc

/*
 * Copyright (c) 2008-2014, Pedigree Developers
 *
 * Please see the CONTRIB file in the root of the source tree for a full
 * list of contributors.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include "Filter.h"
#include "pedigree/kernel/Log.h"
#include "pedigree/kernel/utilities/Iterator.h"
#include "pedigree/kernel/utilities/utility.h"

NetworkFilter NetworkFilter::m_Instance;

NetworkFilter::NetworkFilter() : m_Callbacks()
{
}

NetworkFilter::~NetworkFilter()
{
}

bool NetworkFilter::filter(size_t level, uintptr_t packet, size_t sz)
{
    // Check for a valid level
    if (level <= 4 && level > 0)
    {
        // Grab the callback list
        typedef List<void *>::Iterator callbackIterator;
        List<void *> *list = m_Callbacks.lookup(level);
        if (list)
        {
            // Iterate, call each callback until one returns false
            for (callbackIterator it = list->begin(); it != list->end(); ++it)
            {
                bool (*callback)(uintptr_t, size_t) =
                    reinterpret_cast<bool (*)(uintptr_t, size_t)>(*it);
                bool result = callback(packet, sz);
                if (!result)
                    return result;  // Short-circuit. This way we avoid
                                    // executing extra filters if one says to
                                    // drop.
            }
        }
    }

    // Default response: allow packet
    return true;
}

size_t NetworkFilter::installCallback(
    size_t level, bool (*callback)(uintptr_t, size_t))
{

    // Check for a valid level
    if (level <= 4 && level > 0)
    {
        // Grab the callback list
        List<void *> *list = m_Callbacks.lookup(level);

        // If it already exists, add the callback
        if (list)
        {
            // We return the index into the list of this callback
            size_t index = list->count();
            list->pushBack(reinterpret_cast<void *>(callback));
            return index;
        }
        // Otherwise, allocate
        else
        {
            list = new List<void *>;
            if (!list)
            {
                ERROR(
                    "Ran out of memory creating list for level "
                    << Dec << level << Hex << " callbacks!");
                return static_cast<size_t>(-1);
            }

            list->pushBack(reinterpret_cast<void *>(callback));
            m_Callbacks.insert(level, list);

            // First item
            return 0;
        }
    }

    // Invalid input
    return static_cast<size_t>(-1);
}

void NetworkFilter::removeCallback(size_t level, size_t id)
{
}