ssnmap.c

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/* SCTP kernel implementation
 * Copyright (c) 2003 International Business Machines, Corp.
 *
 * This file is part of the SCTP kernel implementation
 *
 * These functions manipulate sctp SSN tracker.
 *
 * This SCTP implementation is free software;
 * you can redistribute it and/or modify it under the terms of
 * the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This SCTP implementation is distributed in the hope that it
 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
 *                 ************************
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with GNU CC; see the file COPYING.  If not, write to
 * the Free Software Foundation, 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 *
 * Please send any bug reports or fixes you make to the
 * email address(es):
 *    lksctp developers <lksctp-developers@lists.sourceforge.net>
 *
 * Or submit a bug report through the following website:
 *    http://www.sf.net/projects/lksctp
 *
 * Written or modified by:
 *    Jon Grimm             <jgrimm@us.ibm.com>
 *
 * Any bugs reported given to us we will try to fix... any fixes shared will
 * be incorporated into the next SCTP release.
 */

#include <linux/types.h>
#include <linux/slab.h>
#include <net/sctp/sctp.h>
#include <net/sctp/sm.h>

#define MAX_KMALLOC_SIZE    131072

static struct sctp_ssnmap *sctp_ssnmap_init(struct sctp_ssnmap *map, __u16 in,
                        __u16 out);

/* Storage size needed for map includes 2 headers and then the
 * specific needs of in or out streams.
 */
static inline size_t sctp_ssnmap_size(__u16 in, __u16 out)
{
    return sizeof(struct sctp_ssnmap) + (in + out) * sizeof(__u16);
}


/* Create a new sctp_ssnmap.
 * Allocate room to store at least 'len' contiguous TSNs.
 */
struct sctp_ssnmap *sctp_ssnmap_new(__u16 in, __u16 out,
                    gfp_t gfp)
{
    struct sctp_ssnmap *retval;
    int size;

    size = sctp_ssnmap_size(in, out);
    if (size <= MAX_KMALLOC_SIZE)
        retval = kmalloc(size, gfp);
    else
        retval = (struct sctp_ssnmap *)
              __get_free_pages(gfp, get_order(size));
    if (!retval)
        goto fail;

    if (!sctp_ssnmap_init(retval, in, out))
        goto fail_map;

    retval->malloced = 1;
    SCTP_DBG_OBJCNT_INC(ssnmap);

    return retval;

fail_map:
    if (size <= MAX_KMALLOC_SIZE)
        kfree(retval);
    else
        free_pages((unsigned long)retval, get_order(size));
fail:
    return NULL;
}


/* Initialize a block of memory as a ssnmap.  */
static struct sctp_ssnmap *sctp_ssnmap_init(struct sctp_ssnmap *map, __u16 in,
                        __u16 out)
{
    memset(map, 0x00, sctp_ssnmap_size(in, out));

    /* Start 'in' stream just after the map header. */
    map->in.ssn = (__u16 *)&map[1];
    map->in.len = in;

    /* Start 'out' stream just after 'in'. */
    map->out.ssn = &map->in.ssn[in];
    map->out.len = out;

    return map;
}

/* Clear out the ssnmap streams.  */
void sctp_ssnmap_clear(struct sctp_ssnmap *map)
{
    size_t size;

    size = (map->in.len + map->out.len) * sizeof(__u16);
    memset(map->in.ssn, 0x00, size);
}

/* Dispose of a ssnmap.  */
void sctp_ssnmap_free(struct sctp_ssnmap *map)
{
    if (map && map->malloced) {
        int size;

        size = sctp_ssnmap_size(map->in.len, map->out.len);
        if (size <= MAX_KMALLOC_SIZE)
            kfree(map);
        else
            free_pages((unsigned long)map, get_order(size));
        SCTP_DBG_OBJCNT_DEC(ssnmap);
    }
}