1/* SCTP kernel reference Implementation
2 * Copyright (c) 2003 International Business Machines, Corp.
3 *
4 * This file is part of the SCTP kernel reference Implementation
5 *
6 * These functions manipulate sctp SSN tracker.
7 *
8 * The SCTP reference 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 * The SCTP reference 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 <net/sctp/sctp.h>
41#include <net/sctp/sm.h>
42
43#define MAX_KMALLOC_SIZE	131072
44
45static struct sctp_ssnmap *sctp_ssnmap_init(struct sctp_ssnmap *map, __u16 in,
46					    __u16 out);
47
48/* Storage size needed for map includes 2 headers and then the
49 * specific needs of in or out streams.
50 */
51static inline size_t sctp_ssnmap_size(__u16 in, __u16 out)
52{
53	return sizeof(struct sctp_ssnmap) + (in + out) * sizeof(__u16);
54}
55
56
57/* Create a new sctp_ssnmap.
58 * Allocate room to store at least 'len' contiguous TSNs.
59 */
60struct sctp_ssnmap *sctp_ssnmap_new(__u16 in, __u16 out,
61				    gfp_t gfp)
62{
63	struct sctp_ssnmap *retval;
64	int size;
65
66	size = sctp_ssnmap_size(in, out);
67	if (size <= MAX_KMALLOC_SIZE)
68		retval = kmalloc(size, gfp);
69	else
70		retval = (struct sctp_ssnmap *)
71			  __get_free_pages(gfp, get_order(size));
72	if (!retval)
73		goto fail;
74
75	if (!sctp_ssnmap_init(retval, in, out))
76		goto fail_map;
77
78	retval->malloced = 1;
79	SCTP_DBG_OBJCNT_INC(ssnmap);
80
81	return retval;
82
83fail_map:
84	if (size <= MAX_KMALLOC_SIZE)
85		kfree(retval);
86	else
87		free_pages((unsigned long)retval, get_order(size));
88fail:
89	return NULL;
90}
91
92
93/* Initialize a block of memory as a ssnmap.  */
94static struct sctp_ssnmap *sctp_ssnmap_init(struct sctp_ssnmap *map, __u16 in,
95					    __u16 out)
96{
97	memset(map, 0x00, sctp_ssnmap_size(in, out));
98
99	/* Start 'in' stream just after the map header. */
100	map->in.ssn = (__u16 *)&map[1];
101	map->in.len = in;
102
103	/* Start 'out' stream just after 'in'. */
104	map->out.ssn = &map->in.ssn[in];
105	map->out.len = out;
106
107	return map;
108}
109
110/* Clear out the ssnmap streams.  */
111void sctp_ssnmap_clear(struct sctp_ssnmap *map)
112{
113	size_t size;
114
115	size = (map->in.len + map->out.len) * sizeof(__u16);
116	memset(map->in.ssn, 0x00, size);
117}
118
119/* Dispose of a ssnmap.  */
120void sctp_ssnmap_free(struct sctp_ssnmap *map)
121{
122	if (map && map->malloced) {
123		int size;
124
125		size = sctp_ssnmap_size(map->in.len, map->out.len);
126		if (size <= MAX_KMALLOC_SIZE)
127			kfree(map);
128		else
129			free_pages((unsigned long)map, get_order(size));
130		SCTP_DBG_OBJCNT_DEC(ssnmap);
131	}
132}
133