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