source: mainline/uspace/lib/packet/generic/packet_server.c@ a4ee3ab2

/*
 * Copyright (c) 2009 Lukas Mejdrech
 * 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.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 */

/** @addtogroup libpacket
 *  @{
 */

/** @file
 * Packet server implementation.
 */

#include <packet_server.h>
#include <align.h>
#include <assert.h>
#include <async.h>
#include <errno.h>
#include <fibril_synch.h>
#include <unistd.h>
#include <sys/mman.h>
#include <ipc/packet.h>
#include <ipc/net.h>
#include <net/packet.h>
#include <net/packet_header.h>

#define FREE_QUEUES_COUNT       7

/** The default address length reserved for new packets. */
#define DEFAULT_ADDR_LEN        32

/** The default prefix reserved for new packets. */
#define DEFAULT_PREFIX          64

/** The default suffix reserved for new packets. */
#define DEFAULT_SUFFIX          64

/** Packet server global data. */
static struct {
        /** Safety lock. */
        fibril_mutex_t lock;
        /** Free packet queues. */
        packet_t *free[FREE_QUEUES_COUNT];
        
        /**
         * Packet length upper bounds of the free packet queues. The maximal
         * lengths of packets in each queue in the ascending order. The last
         * queue is not limited.
         */
        size_t sizes[FREE_QUEUES_COUNT];
        
        /** Total packets allocated. */
        unsigned int count;
} ps_globals = {
        .lock = FIBRIL_MUTEX_INITIALIZER(ps_globals.lock),
        .free = {
                NULL,
                NULL,
                NULL,
                NULL,
                NULL,
                NULL,
                NULL
        },
        .sizes = {
                PAGE_SIZE,
                PAGE_SIZE * 2,
                PAGE_SIZE * 4,
                PAGE_SIZE * 8,
                PAGE_SIZE * 16,
                PAGE_SIZE * 32,
                PAGE_SIZE * 64
        },
        .count = 0
};

/** Clears and initializes the packet according to the given dimensions.
 *
 * @param[in] packet    The packet to be initialized.
 * @param[in] addr_len  The source and destination addresses maximal length in
 *                      bytes.
 * @param[in] max_prefix The maximal prefix length in bytes.
 * @param[in] max_content The maximal content length in bytes.
 * @param[in] max_suffix The maximal suffix length in bytes.
 */
static void
packet_init(packet_t *packet, size_t addr_len, size_t max_prefix,
    size_t max_content, size_t max_suffix)
{
        /* Clear the packet content */
        bzero(((void *) packet) + sizeof(packet_t),
            packet->length - sizeof(packet_t));
        
        /* Clear the packet header */
        packet->order = 0;
        packet->metric = 0;
        packet->previous = 0;
        packet->next = 0;
        packet->addr_len = 0;
        packet->src_addr = sizeof(packet_t);
        packet->dest_addr = packet->src_addr + addr_len;
        packet->max_prefix = max_prefix;
        packet->max_content = max_content;
        packet->data_start = packet->dest_addr + addr_len + packet->max_prefix;
        packet->data_end = packet->data_start;
}

/** Creates a new packet of dimensions at least as given.
 *
 * @param[in] length    The total length of the packet, including the header,
 *                      the addresses and the data of the packet.
 * @param[in] addr_len  The source and destination addresses maximal length in
 *                      bytes.
 * @param[in] max_prefix The maximal prefix length in bytes.
 * @param[in] max_content The maximal content length in bytes.
 * @param[in] max_suffix The maximal suffix length in bytes.
 * @return              The packet of dimensions at least as given.
 * @return              NULL if there is not enough memory left.
 */
static packet_t *
packet_create(size_t length, size_t addr_len, size_t max_prefix,
    size_t max_content, size_t max_suffix)
{
        packet_t *packet;
        int rc;

        assert(fibril_mutex_is_locked(&ps_globals.lock));

        /* Already locked */
        packet = (packet_t *) mmap(NULL, length, PROTO_READ | PROTO_WRITE,
            MAP_SHARED | MAP_ANONYMOUS, 0, 0);
        if (packet == MAP_FAILED)
                return NULL;

        ps_globals.count++;
        packet->packet_id = ps_globals.count;
        packet->length = length;
        packet_init(packet, addr_len, max_prefix, max_content, max_suffix);
        packet->magic_value = PACKET_MAGIC_VALUE;
        rc = pm_add(packet);
        if (rc != EOK) {
                munmap(packet, packet->length);
                return NULL;
        }
        
        return packet;
}

/** Return the packet of dimensions at least as given.
 *
 * Try to reuse free packets first.
 * Create a new packet aligned to the memory page size if none available.
 * Lock the global data during its processing.
 *
 * @param[in] addr_len  The source and destination addresses maximal length in
 *                      bytes.
 * @param[in] max_prefix The maximal prefix length in bytes.
 * @param[in] max_content The maximal content length in bytes.
 * @param[in] max_suffix The maximal suffix length in bytes.
 * @return              The packet of dimensions at least as given.
 * @return              NULL if there is not enough memory left.
 */
static packet_t *
packet_get_local(size_t addr_len, size_t max_prefix, size_t max_content,
    size_t max_suffix)
{
        size_t length = ALIGN_UP(sizeof(packet_t) + 2 * addr_len +
            max_prefix + max_content + max_suffix, PAGE_SIZE);
        
        fibril_mutex_lock(&ps_globals.lock);
        
        packet_t *packet;
        unsigned int index;
        
        for (index = 0; index < FREE_QUEUES_COUNT; index++) {
                if ((length > ps_globals.sizes[index]) &&
                    (index < FREE_QUEUES_COUNT - 1))
                        continue;
                
                packet = ps_globals.free[index];
                while (packet_is_valid(packet) && (packet->length < length))
                        packet = pm_find(packet->next);
                
                if (packet_is_valid(packet)) {
                        if (packet == ps_globals.free[index])
                                ps_globals.free[index] = pq_detach(packet);
                        else
                                pq_detach(packet);
                        
                        packet_init(packet, addr_len, max_prefix, max_content,
                            max_suffix);
                        fibril_mutex_unlock(&ps_globals.lock);
                        
                        return packet;
                }
        }
        
        packet = packet_create(length, addr_len, max_prefix, max_content,
            max_suffix);
        
        fibril_mutex_unlock(&ps_globals.lock);
        
        return packet;
}

/** Release the packet and returns it to the appropriate free packet queue.
 *
 * @param[in] packet    The packet to be released.
 *
 */
static void packet_release(packet_t *packet)
{
        int index;
        int result;

        assert(fibril_mutex_is_locked(&ps_globals.lock));

        for (index = 0; (index < FREE_QUEUES_COUNT - 1) &&
            (packet->length > ps_globals.sizes[index]); index++) {
                ;
        }
        
        result = pq_add(&ps_globals.free[index], packet, packet->length,
            packet->length);
        assert(result == EOK);
}

/** Releases the packet queue.
 *
 * @param[in] packet_id The first packet identifier.
 * @return              EOK on success.
 * @return              ENOENT if there is no such packet.
 */
static int packet_release_wrapper(packet_id_t packet_id)
{
        packet_t *packet;

        packet = pm_find(packet_id);
        if (!packet_is_valid(packet))
                return ENOENT;

        fibril_mutex_lock(&ps_globals.lock);
        pq_destroy(packet, packet_release);
        fibril_mutex_unlock(&ps_globals.lock);

        return EOK;
}

/** Shares the packet memory block.
 * @param[in] packet    The packet to be shared.
 * @return              EOK on success.
 * @return              EINVAL if the packet is not valid.
 * @return              EINVAL if the calling module does not accept the memory.
 * @return              ENOMEM if the desired and actual sizes differ.
 * @return              Other error codes as defined for the
 *                      async_share_in_finalize() function.
 */
static int packet_reply(packet_t *packet)
{
        ipc_callid_t callid;
        size_t size;

        if (!packet_is_valid(packet))
                return EINVAL;

        if (!async_share_in_receive(&callid, &size)) {
                async_answer_0(callid, EINVAL);
                return EINVAL;
        }

        if (size != packet->length) {
                async_answer_0(callid, ENOMEM);
                return ENOMEM;
        }
        
        return async_share_in_finalize(callid, packet,
            PROTO_READ | PROTO_WRITE);
}

/** Processes the packet server message.
 *
 * @param[in] callid    The message identifier.
 * @param[in] call      The message parameters.
 * @param[out] answer   The message answer parameters.
 * @param[out] answer_count The last parameter for the actual answer in the
 *                      answer parameter.
 * @return              EOK on success.
 * @return              ENOMEM if there is not enough memory left.
 * @return              ENOENT if there is no such packet as in the packet
 *                      message parameter.
 * @return              ENOTSUP if the message is not known.
 * @return              Other error codes as defined for the
 *                      packet_release_wrapper() function.
 */
int packet_server_message(ipc_callid_t callid, ipc_call_t *call, ipc_call_t *answer,
    size_t *answer_count)
{
        packet_t *packet;
        
        if (!IPC_GET_IMETHOD(*call))
                return EOK;
        
        *answer_count = 0;
        switch (IPC_GET_IMETHOD(*call)) {
        case NET_PACKET_CREATE_1:
                packet = packet_get_local(DEFAULT_ADDR_LEN, DEFAULT_PREFIX,
                    IPC_GET_CONTENT(*call), DEFAULT_SUFFIX);
                if (!packet)
                        return ENOMEM;
                *answer_count = 2;
                IPC_SET_ARG1(*answer, (sysarg_t) packet->packet_id);
                IPC_SET_ARG2(*answer, (sysarg_t) packet->length);
                return EOK;
        
        case NET_PACKET_CREATE_4:
                packet = packet_get_local(
                    ((DEFAULT_ADDR_LEN < IPC_GET_ADDR_LEN(*call)) ?
                    IPC_GET_ADDR_LEN(*call) : DEFAULT_ADDR_LEN),
                    DEFAULT_PREFIX + IPC_GET_PREFIX(*call),
                    IPC_GET_CONTENT(*call),
                    DEFAULT_SUFFIX + IPC_GET_SUFFIX(*call));
                if (!packet)
                        return ENOMEM;
                *answer_count = 2;
                IPC_SET_ARG1(*answer, (sysarg_t) packet->packet_id);
                IPC_SET_ARG2(*answer, (sysarg_t) packet->length);
                return EOK;
        
        case NET_PACKET_GET:
                packet = pm_find(IPC_GET_ID(*call));
                if (!packet_is_valid(packet))
                        return ENOENT;
                return packet_reply(packet);
        
        case NET_PACKET_GET_SIZE:
                packet = pm_find(IPC_GET_ID(*call));
                if (!packet_is_valid(packet))
                        return ENOENT;
                IPC_SET_ARG1(*answer, (sysarg_t) packet->length);
                *answer_count = 1;
                return EOK;
        
        case NET_PACKET_RELEASE:
                return packet_release_wrapper(IPC_GET_ID(*call));
        }
        
        return ENOTSUP;
}

/** @}
 */