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 <net/sctp/sctp.h>
  41#include <net/sctp/sm.h>
  42
  43#define MAX_KMALLOC_SIZE        131072
  44
  45static struct sctp_ssnmap *sctp_ssnmap_init(struct sctp_ssnmap *map, __u16 in,
  46                                            __u16 out);
  47
  48/* Storage size needed for map includes 2 headers and then the
  49 * specific needs of in or out streams.
  50 */
  51static inline size_t sctp_ssnmap_size(__u16 in, __u16 out)
  52{
  53        return sizeof(struct sctp_ssnmap) + (in + out) * sizeof(__u16);
  54}
  55
  56
  57/* Create a new sctp_ssnmap.
  58 * Allocate room to store at least 'len' contiguous TSNs.
  59 */
  60struct sctp_ssnmap *sctp_ssnmap_new(__u16 in, __u16 out,
  61                                    gfp_t gfp)
  62{
  63        struct sctp_ssnmap *retval;
  64        int size;
  65
  66        size = sctp_ssnmap_size(in, out);
  67        if (size <= MAX_KMALLOC_SIZE)
  68                retval = kmalloc(size, gfp);
  69        else
  70                retval = (struct sctp_ssnmap *)
  71                          __get_free_pages(gfp, get_order(size));
  72        if (!retval)
  73                goto fail;
  74
  75        if (!sctp_ssnmap_init(retval, in, out))
  76                goto fail_map;
  77
  78        retval->malloced = 1;
  79        SCTP_DBG_OBJCNT_INC(ssnmap);
  80
  81        return retval;
  82
  83fail_map:
  84        if (size <= MAX_KMALLOC_SIZE)
  85                kfree(retval);
  86        else
  87                free_pages((unsigned long)retval, get_order(size));
  88fail:
  89        return NULL;
  90}
  91
  92
  93/* Initialize a block of memory as a ssnmap.  */
  94static struct sctp_ssnmap *sctp_ssnmap_init(struct sctp_ssnmap *map, __u16 in,
  95                                            __u16 out)
  96{
  97        memset(map, 0x00, sctp_ssnmap_size(in, out));
  98
  99        /* Start 'in' stream just after the map header. */
 100        map->in.ssn = (__u16 *)&map[1];
 101        map->in.len = in;
 102
 103        /* Start 'out' stream just after 'in'. */
 104        map->out.ssn = &map->in.ssn[in];
 105        map->out.len = out;
 106
 107        return map;
 108}
 109
 110/* Clear out the ssnmap streams.  */
 111void sctp_ssnmap_clear(struct sctp_ssnmap *map)
 112{
 113        size_t size;
 114
 115        size = (map->in.len + map->out.len) * sizeof(__u16);
 116        memset(map->in.ssn, 0x00, size);
 117}
 118
 119/* Dispose of a ssnmap.  */
 120void sctp_ssnmap_free(struct sctp_ssnmap *map)
 121{
 122        if (map && map->malloced) {
 123                int size;
 124
 125                size = sctp_ssnmap_size(map->in.len, map->out.len);
 126                if (size <= MAX_KMALLOC_SIZE)
 127                        kfree(map);
 128                else
 129                        free_pages((unsigned long)map, get_order(size));
 130                SCTP_DBG_OBJCNT_DEC(ssnmap);
 131        }
 132}
 133