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}