linux/net/sctp/ssnmap.c
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   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
  44#define MAX_KMALLOC_SIZE        131072
  45
  46static struct sctp_ssnmap *sctp_ssnmap_init(struct sctp_ssnmap *map, __u16 in,
  47                                            __u16 out);
  48
  49/* Storage size needed for map includes 2 headers and then the
  50 * specific needs of in or out streams.
  51 */
  52static inline size_t sctp_ssnmap_size(__u16 in, __u16 out)
  53{
  54        return sizeof(struct sctp_ssnmap) + (in + out) * sizeof(__u16);
  55}
  56
  57
  58/* Create a new sctp_ssnmap.
  59 * Allocate room to store at least 'len' contiguous TSNs.
  60 */
  61struct sctp_ssnmap *sctp_ssnmap_new(__u16 in, __u16 out,
  62                                    gfp_t gfp)
  63{
  64        struct sctp_ssnmap *retval;
  65        int size;
  66
  67        size = sctp_ssnmap_size(in, out);
  68        if (size <= MAX_KMALLOC_SIZE)
  69                retval = kmalloc(size, gfp);
  70        else
  71                retval = (struct sctp_ssnmap *)
  72                          __get_free_pages(gfp, get_order(size));
  73        if (!retval)
  74                goto fail;
  75
  76        if (!sctp_ssnmap_init(retval, in, out))
  77                goto fail_map;
  78
  79        retval->malloced = 1;
  80        SCTP_DBG_OBJCNT_INC(ssnmap);
  81
  82        return retval;
  83
  84fail_map:
  85        if (size <= MAX_KMALLOC_SIZE)
  86                kfree(retval);
  87        else
  88                free_pages((unsigned long)retval, get_order(size));
  89fail:
  90        return NULL;
  91}
  92
  93
  94/* Initialize a block of memory as a ssnmap.  */
  95static struct sctp_ssnmap *sctp_ssnmap_init(struct sctp_ssnmap *map, __u16 in,
  96                                            __u16 out)
  97{
  98        memset(map, 0x00, sctp_ssnmap_size(in, out));
  99
 100        /* Start 'in' stream just after the map header. */
 101        map->in.ssn = (__u16 *)&map[1];
 102        map->in.len = in;
 103
 104        /* Start 'out' stream just after 'in'. */
 105        map->out.ssn = &map->in.ssn[in];
 106        map->out.len = out;
 107
 108        return map;
 109}
 110
 111/* Clear out the ssnmap streams.  */
 112void sctp_ssnmap_clear(struct sctp_ssnmap *map)
 113{
 114        size_t size;
 115
 116        size = (map->in.len + map->out.len) * sizeof(__u16);
 117        memset(map->in.ssn, 0x00, size);
 118}
 119
 120/* Dispose of a ssnmap.  */
 121void sctp_ssnmap_free(struct sctp_ssnmap *map)
 122{
 123        if (map && map->malloced) {
 124                int size;
 125
 126                size = sctp_ssnmap_size(map->in.len, map->out.len);
 127                if (size <= MAX_KMALLOC_SIZE)
 128                        kfree(map);
 129                else
 130                        free_pages((unsigned long)map, get_order(size));
 131                SCTP_DBG_OBJCNT_DEC(ssnmap);
 132        }
 133}
 134
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