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 <linux-sctp@vger.kernel.org>
  28  *
  29  * Written or modified by:
  30  *    Jon Grimm             <jgrimm@us.ibm.com>
  31  */
  32
  33 #include <linux/types.h>
  34 #include <linux/slab.h>
  35 #include <net/sctp/sctp.h>
  36 #include <net/sctp/sm.h>
  37
  38 static struct sctp_ssnmap *sctp_ssnmap_init(struct sctp_ssnmap *map, __u16 in,
  39                                             __u16 out);
  40
  41 /* Storage size needed for map includes 2 headers and then the
  42  * specific needs of in or out streams.
  43  */
  44 static inline size_t sctp_ssnmap_size(__u16 in, __u16 out)
  45 {
  46         return sizeof(struct sctp_ssnmap) + (in + out) * sizeof(__u16);
  47 }
  48
  49
  50 /* Create a new sctp_ssnmap.
  51  * Allocate room to store at least 'len' contiguous TSNs.
  52  */
  53 struct sctp_ssnmap *sctp_ssnmap_new(__u16 in, __u16 out,
  54                                     gfp_t gfp)
  55 {
  56         struct sctp_ssnmap *retval;
  57         int size;
  58
  59         size = sctp_ssnmap_size(in, out);
  60         if (size <= KMALLOC_MAX_SIZE)
  61                 retval = kmalloc(size, gfp);
  62         else
  63                 retval = (struct sctp_ssnmap *)
  64                           __get_free_pages(gfp, get_order(size));
  65         if (!retval)
  66                 goto fail;
  67
  68         if (!sctp_ssnmap_init(retval, in, out))
  69                 goto fail_map;
  70
  71         SCTP_DBG_OBJCNT_INC(ssnmap);
  72
  73         return retval;
  74
  75 fail_map:
  76         if (size <= KMALLOC_MAX_SIZE)
  77                 kfree(retval);
  78         else
  79                 free_pages((unsigned long)retval, get_order(size));
  80 fail:
  81         return NULL;
  82 }
  83
  84
  85 /* Initialize a block of memory as a ssnmap.  */
  86 static struct sctp_ssnmap *sctp_ssnmap_init(struct sctp_ssnmap *map, __u16 in,
  87                                             __u16 out)
  88 {
  89         memset(map, 0x00, sctp_ssnmap_size(in, out));
  90
  91         /* Start 'in' stream just after the map header. */
  92         map->in.ssn = (__u16 *)&map[1];
  93         map->in.len = in;
  94
  95         /* Start 'out' stream just after 'in'. */
  96         map->out.ssn = &map->in.ssn[in];
  97         map->out.len = out;
  98
  99         return map;
 100 }
 101
 102 /* Clear out the ssnmap streams.  */
 103 void sctp_ssnmap_clear(struct sctp_ssnmap *map)
 104 {
 105         size_t size;
 106
 107         size = (map->in.len + map->out.len) * sizeof(__u16);
 108         memset(map->in.ssn, 0x00, size);
 109 }
 110
 111 /* Dispose of a ssnmap.  */
 112 void sctp_ssnmap_free(struct sctp_ssnmap *map)
 113 {
 114         int size;
 115
 116         if (unlikely(!map))
 117                 return;
 118
 119         size = sctp_ssnmap_size(map->in.len, map->out.len);
 120         if (size <= KMALLOC_MAX_SIZE)
 121                 kfree(map);
 122         else
 123                 free_pages((unsigned long)map, get_order(size));
 124
 125         SCTP_DBG_OBJCNT_DEC(ssnmap);
 126 }