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
 37static 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 */
 43static 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 */
 52struct 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
 74fail_map:
 75	if (size <= KMALLOC_MAX_SIZE)
 76		kfree(retval);
 77	else
 78		free_pages((unsigned long)retval, get_order(size));
 79fail:
 80	return NULL;
 81}
 82
 83
 84/* Initialize a block of memory as a ssnmap.  */
 85static 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.  */
102void 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.  */
111void 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}