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: releng/12.0/sys/netinet/sctp_crc32.c 336508 2018-07-19 20:11:14Z tuexen $");
37
38 #include "opt_sctp.h"
39
40 #ifdef SCTP
41 #include <netinet/sctp_os.h>
42 #include <netinet/sctp.h>
43 #include <netinet/sctp_crc32.h>
44 #include <netinet/sctp_pcb.h>
45 #else
46 #include <sys/param.h>
47 #include <sys/systm.h>
48 #include <sys/mbuf.h>
49
50 #include <netinet/sctp_crc32.h>
51 #endif
52
53 static uint32_t
54 sctp_finalize_crc32c(uint32_t crc32c)
55 {
56 uint32_t result;
57 #if BYTE_ORDER == BIG_ENDIAN
58 uint8_t byte0, byte1, byte2, byte3;
59 #endif
60
61 /* Complement the result */
62 result = ~crc32c;
63 #if BYTE_ORDER == BIG_ENDIAN
64 /*
65 * For BIG-ENDIAN platforms the result is in little-endian form. So
66 * we must swap the bytes to return the result in network byte
67 * order.
68 */
69 byte0 = result & 0x000000ff;
70 byte1 = (result >> 8) & 0x000000ff;
71 byte2 = (result >> 16) & 0x000000ff;
72 byte3 = (result >> 24) & 0x000000ff;
73 crc32c = ((byte0 << 24) | (byte1 << 16) | (byte2 << 8) | byte3);
74 #else
75 /*
76 * For LITTLE ENDIAN platforms the result is in already in network
77 * byte order.
78 */
79 crc32c = result;
80 #endif
81 return (crc32c);
82 }
83
84 /*
85 * Compute the SCTP checksum in network byte order for a given mbuf chain m
86 * which contains an SCTP packet starting at offset.
87 * Since this function is also called by ipfw, don't assume that
88 * it is compiled on a kernel with SCTP support.
89 */
90 uint32_t
91 sctp_calculate_cksum(struct mbuf *m, uint32_t offset)
92 {
93 uint32_t base = 0xffffffff;
94
95 while (offset > 0) {
96 KASSERT(m != NULL, ("sctp_calculate_cksum, offset > length of mbuf chain"));
97 if (offset < (uint32_t)m->m_len) {
98 break;
99 }
100 offset -= m->m_len;
101 m = m->m_next;
102 }
103 if (offset > 0) {
104 base = calculate_crc32c(base,
105 (unsigned char *)(m->m_data + offset),
106 (unsigned int)(m->m_len - offset));
107 m = m->m_next;
108 }
109 while (m != NULL) {
110 base = calculate_crc32c(base,
111 (unsigned char *)m->m_data,
112 (unsigned int)m->m_len);
113 m = m->m_next;
114 }
115 base = sctp_finalize_crc32c(base);
116 return (base);
117 }
118
119 #ifdef SCTP
120 /*
121 * Compute and insert the SCTP checksum in network byte order for a given
122 * mbuf chain m which contains an SCTP packet starting at offset.
123 */
124 void
125 sctp_delayed_cksum(struct mbuf *m, uint32_t offset)
126 {
127 uint32_t checksum;
128
129 checksum = sctp_calculate_cksum(m, offset);
130 SCTP_STAT_DECR(sctps_sendhwcrc);
131 SCTP_STAT_INCR(sctps_sendswcrc);
132 offset += offsetof(struct sctphdr, checksum);
133
134 if (offset + sizeof(uint32_t) > (uint32_t)(m->m_len)) {
135 #ifdef INVARIANTS
136 panic("sctp_delayed_cksum(): m->m_len: %d, offset: %u.",
137 m->m_len, offset);
138 #else
139 SCTP_PRINTF("sctp_delayed_cksum(): m->m_len: %d, offset: %u.\n",
140 m->m_len, offset);
141 #endif
142 return;
143 }
144 *(uint32_t *)(m->m_data + offset) = checksum;
145 }
146 #endif
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