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, write to
  22 * the Free Software Foundation, 59 Temple Place - Suite 330,
  23 * Boston, MA 02111-1307, USA.
  24 *
  25 * Please send any bug reports or fixes you make to the
  26 * email address(es):
  27 *    lksctp developers <lksctp-developers@lists.sourceforge.net>
  28 *
  29 * Or submit a bug report through the following website:
  30 *    http://www.sf.net/projects/lksctp
  31 *
  32 * Written or modified by:
  33 *    Jon Grimm             <jgrimm@us.ibm.com>
  34 *
  35 * Any bugs reported given to us we will try to fix... any fixes shared will
  36 * be incorporated into the next SCTP release.
  37 */
  38
  39#include <linux/types.h>
  40#include <linux/slab.h>
  41#include <net/sctp/sctp.h>
  42#include <net/sctp/sm.h>
  43
  44static struct sctp_ssnmap *sctp_ssnmap_init(struct sctp_ssnmap *map, __u16 in,
  45                                            __u16 out);
  46
  47/* Storage size needed for map includes 2 headers and then the
  48 * specific needs of in or out streams.
  49 */
  50static inline size_t sctp_ssnmap_size(__u16 in, __u16 out)
  51{
  52        return sizeof(struct sctp_ssnmap) + (in + out) * sizeof(__u16);
  53}
  54
  55
  56/* Create a new sctp_ssnmap.
  57 * Allocate room to store at least 'len' contiguous TSNs.
  58 */
  59struct sctp_ssnmap *sctp_ssnmap_new(__u16 in, __u16 out,
  60                                    gfp_t gfp)
  61{
  62        struct sctp_ssnmap *retval;
  63        int size;
  64
  65        size = sctp_ssnmap_size(in, out);
  66        if (size <= KMALLOC_MAX_SIZE)
  67                retval = kmalloc(size, gfp);
  68        else
  69                retval = (struct sctp_ssnmap *)
  70                          __get_free_pages(gfp, get_order(size));
  71        if (!retval)
  72                goto fail;
  73
  74        if (!sctp_ssnmap_init(retval, in, out))
  75                goto fail_map;
  76
  77        SCTP_DBG_OBJCNT_INC(ssnmap);
  78
  79        return retval;
  80
  81fail_map:
  82        if (size <= KMALLOC_MAX_SIZE)
  83                kfree(retval);
  84        else
  85                free_pages((unsigned long)retval, get_order(size));
  86fail:
  87        return NULL;
  88}
  89
  90
  91/* Initialize a block of memory as a ssnmap.  */
  92static struct sctp_ssnmap *sctp_ssnmap_init(struct sctp_ssnmap *map, __u16 in,
  93                                            __u16 out)
  94{
  95        memset(map, 0x00, sctp_ssnmap_size(in, out));
  96
  97        /* Start 'in' stream just after the map header. */
  98        map->in.ssn = (__u16 *)&map[1];
  99        map->in.len = in;
 100
 101        /* Start 'out' stream just after 'in'. */
 102        map->out.ssn = &map->in.ssn[in];
 103        map->out.len = out;
 104
 105        return map;
 106}
 107
 108/* Clear out the ssnmap streams.  */
 109void sctp_ssnmap_clear(struct sctp_ssnmap *map)
 110{
 111        size_t size;
 112
 113        size = (map->in.len + map->out.len) * sizeof(__u16);
 114        memset(map->in.ssn, 0x00, size);
 115}
 116
 117/* Dispose of a ssnmap.  */
 118void sctp_ssnmap_free(struct sctp_ssnmap *map)
 119{
 120        int size;
 121
 122        if (unlikely(!map))
 123                return;
 124
 125        size = sctp_ssnmap_size(map->in.len, map->out.len);
 126        if (size <= KMALLOC_MAX_SIZE)
 127                kfree(map);
 128        else
 129                free_pages((unsigned long)map, get_order(size));
 130
 131        SCTP_DBG_OBJCNT_DEC(ssnmap);
 132}
 133