1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 2001-2007, by Cisco Systems, Inc. All rights reserved.
5 * Copyright (c) 2008-2012, by Randall Stewart. All rights reserved.
6 * Copyright (c) 2008-2012, by Michael Tuexen. All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions are met:
10 *
11 * a) Redistributions of source code must retain the above copyright notice,
12 *   this list of conditions and the following disclaimer.
13 *
14 * b) Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in
16 *   the documentation and/or other materials provided with the distribution.
17 *
18 * c) Neither the name of Cisco Systems, Inc. nor the names of its
19 *    contributors may be used to endorse or promote products derived
20 *    from this software without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
23 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
24 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
26 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
27 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
28 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
29 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
30 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
31 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
32 * THE POSSIBILITY OF SUCH DAMAGE.
33 */
34
35#include <sys/cdefs.h>
36__FBSDID("$FreeBSD$");
37
38#include "opt_sctp.h"
39
40#include <sys/param.h>
41#include <sys/systm.h>
42#include <sys/gsb_crc32.h>
43#include <sys/mbuf.h>
44
45#include <netinet/sctp.h>
46#include <netinet/sctp_crc32.h>
47#if defined(SCTP) || defined(SCTP_SUPPORT)
48#include <netinet/sctp_os.h>
49#include <netinet/sctp_pcb.h>
50#endif
51
52static uint32_t
53sctp_finalize_crc32c(uint32_t crc32c)
54{
55	uint32_t result;
56#if BYTE_ORDER == BIG_ENDIAN
57	uint8_t byte0, byte1, byte2, byte3;
58#endif
59
60	/* Complement the result */
61	result = ~crc32c;
62#if BYTE_ORDER == BIG_ENDIAN
63	/*
64	 * For BIG-ENDIAN platforms the result is in little-endian form. So
65	 * we must swap the bytes to return the result in network byte
66	 * order.
67	 */
68	byte0 = result & 0x000000ff;
69	byte1 = (result >> 8) & 0x000000ff;
70	byte2 = (result >> 16) & 0x000000ff;
71	byte3 = (result >> 24) & 0x000000ff;
72	crc32c = ((byte0 << 24) | (byte1 << 16) | (byte2 << 8) | byte3);
73#else
74	/*
75	 * For LITTLE ENDIAN platforms the result is in already in network
76	 * byte order.
77	 */
78	crc32c = result;
79#endif
80	return (crc32c);
81}
82
83/*
84 * Compute the SCTP checksum in network byte order for a given mbuf chain m
85 * which contains an SCTP packet starting at offset.
86 * Since this function is also called by ipfw, don't assume that
87 * it is compiled on a kernel with SCTP support.
88 */
89uint32_t
90sctp_calculate_cksum(struct mbuf *m, uint32_t offset)
91{
92	uint32_t base = 0xffffffff;
93
94	while (offset > 0) {
95		KASSERT(m != NULL, ("sctp_calculate_cksum, offset > length of mbuf chain"));
96		if (offset < (uint32_t)m->m_len) {
97			break;
98		}
99		offset -= m->m_len;
100		m = m->m_next;
101	}
102	if (offset > 0) {
103		base = calculate_crc32c(base,
104		    (unsigned char *)(m->m_data + offset),
105		    (unsigned int)(m->m_len - offset));
106		m = m->m_next;
107	}
108	while (m != NULL) {
109		base = calculate_crc32c(base,
110		    (unsigned char *)m->m_data,
111		    (unsigned int)m->m_len);
112		m = m->m_next;
113	}
114	base = sctp_finalize_crc32c(base);
115	return (base);
116}
117
118#if defined(SCTP) || defined(SCTP_SUPPORT)
119
120VNET_DEFINE(struct sctp_base_info, system_base_info);
121
122/*
123 * Compute and insert the SCTP checksum in network byte order for a given
124 * mbuf chain m which contains an SCTP packet starting at offset.
125 */
126void
127sctp_delayed_cksum(struct mbuf *m, uint32_t offset)
128{
129	uint32_t checksum;
130
131	checksum = sctp_calculate_cksum(m, offset);
132	SCTP_STAT_DECR(sctps_sendhwcrc);
133	SCTP_STAT_INCR(sctps_sendswcrc);
134	offset += offsetof(struct sctphdr, checksum);
135
136	if (offset + sizeof(uint32_t) > (uint32_t)(m->m_pkthdr.len)) {
137#ifdef INVARIANTS
138		panic("sctp_delayed_cksum(): m->m_pkthdr.len: %d, offset: %u.",
139		    m->m_pkthdr.len, offset);
140#else
141		SCTP_PRINTF("sctp_delayed_cksum(): m->m_pkthdr.len: %d, offset: %u.\n",
142		    m->m_pkthdr.len, offset);
143#endif
144		return;
145	}
146	m_copyback(m, (int)offset, (int)sizeof(uint32_t), (caddr_t)&checksum);
147}
148#endif
149