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
  44 #define MAX_KMALLOC_SIZE        131072
  45
  46 static 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  */
  52 static 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  */
  61 struct 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
  84 fail_map:
  85         if (size <= MAX_KMALLOC_SIZE)
  86                 kfree(retval);
  87         else
  88                 free_pages((unsigned long)retval, get_order(size));
  89 fail:
  90         return NULL;
  91 }
  92
  93
  94 /* Initialize a block of memory as a ssnmap.  */
  95 static 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.  */
 112 void 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.  */
 121 void 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 }