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}
126