LXR linux/net/sctp/ssnmap.c

   1/* SCTP kernel implementation
   2 * Copyright (c) 2003 International Business Machines, Corp.
   3 *
   4 * This file is part of the SCTP kernel implementation
   5 *
   6 * These functions manipulate sctp SSN tracker.
   7 *
   8 * This SCTP implementation is free software;
   9 * you can redistribute it and/or modify it under the terms of
  10 * the GNU General Public License as published by
  11 * the Free Software Foundation; either version 2, or (at your option)
  12 * any later version.
  13 *
  14 * This SCTP implementation is distributed in the hope that it
  15 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
  16 *                 ************************
  17 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  18 * See the GNU General Public License for more details.
  19 *
  20 * You should have received a copy of the GNU General Public License
  21 * along with GNU CC; see the file COPYING.  If not, see
  22 * <http://www.gnu.org/licenses/>.
  23 *
  24 * Please send any bug reports or fixes you make to the
  25 * email address(es):
  26 *    lksctp developers <linux-sctp@vger.kernel.org>
  27 *
  28 * Written or modified by:
  29 *    Jon Grimm             <jgrimm@us.ibm.com>
  30 */
  31
  32#include <linux/types.h>
  33#include <linux/slab.h>
  34#include <net/sctp/sctp.h>
  35#include <net/sctp/sm.h>
  36
  37static struct sctp_ssnmap *sctp_ssnmap_init(struct sctp_ssnmap *map, __u16 in,
  38                                            __u16 out);
  39
  40/* Storage size needed for map includes 2 headers and then the
  41 * specific needs of in or out streams.
  42 */
  43static inline size_t sctp_ssnmap_size(__u16 in, __u16 out)
  44{
  45        return sizeof(struct sctp_ssnmap) + (in + out) * sizeof(__u16);
  46}
  47
  48
  49/* Create a new sctp_ssnmap.
  50 * Allocate room to store at least 'len' contiguous TSNs.
  51 */
  52struct sctp_ssnmap *sctp_ssnmap_new(__u16 in, __u16 out,
  53                                    gfp_t gfp)
  54{
  55        struct sctp_ssnmap *retval;
  56        int size;
  57
  58        size = sctp_ssnmap_size(in, out);
  59        if (size <= KMALLOC_MAX_SIZE)
  60                retval = kmalloc(size, gfp);
  61        else
  62                retval = (struct sctp_ssnmap *)
  63                          __get_free_pages(gfp, get_order(size));
  64        if (!retval)
  65                goto fail;
  66
  67        if (!sctp_ssnmap_init(retval, in, out))
  68                goto fail_map;
  69
  70        SCTP_DBG_OBJCNT_INC(ssnmap);
  71
  72        return retval;
  73
  74fail_map:
  75        if (size <= KMALLOC_MAX_SIZE)
  76                kfree(retval);
  77        else
  78                free_pages((unsigned long)retval, get_order(size));
  79fail:
  80        return NULL;
  81}
  82
  83
  84/* Initialize a block of memory as a ssnmap.  */
  85static struct sctp_ssnmap *sctp_ssnmap_init(struct sctp_ssnmap *map, __u16 in,
  86                                            __u16 out)
  87{
  88        memset(map, 0x00, sctp_ssnmap_size(in, out));
  89
  90        /* Start 'in' stream just after the map header. */
  91        map->in.ssn = (__u16 *)&map[1];
  92        map->in.len = in;
  93
  94        /* Start 'out' stream just after 'in'. */
  95        map->out.ssn = &map->in.ssn[in];
  96        map->out.len = out;
  97
  98        return map;
  99}
 100
 101/* Clear out the ssnmap streams.  */
 102void sctp_ssnmap_clear(struct sctp_ssnmap *map)
 103{
 104        size_t size;
 105
 106        size = (map->in.len + map->out.len) * sizeof(__u16);
 107        memset(map->in.ssn, 0x00, size);
 108}
 109
 110/* Dispose of a ssnmap.  */
 111void sctp_ssnmap_free(struct sctp_ssnmap *map)
 112{
 113        int size;
 114
 115        if (unlikely(!map))
 116                return;
 117
 118        size = sctp_ssnmap_size(map->in.len, map->out.len);
 119        if (size <= KMALLOC_MAX_SIZE)
 120                kfree(map);
 121        else
 122                free_pages((unsigned long)map, get_order(size));
 123
 124        SCTP_DBG_OBJCNT_DEC(ssnmap);
 125}
 126