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 #include "opt_sctp.h"
37
38 #include <sys/param.h>
39 #include <sys/systm.h>
40 #include <sys/gsb_crc32.h>
41 #include <sys/mbuf.h>
42
43 #include <netinet/sctp.h>
44 #include <netinet/sctp_crc32.h>
45 #if defined(SCTP) || defined(SCTP_SUPPORT)
46 #include <netinet/sctp_os.h>
47 #include <netinet/sctp_pcb.h>
48 #endif
49
50 static uint32_t
sctp_finalize_crc32c(uint32_t crc32c)51 sctp_finalize_crc32c(uint32_t crc32c)
52 {
53 #if BYTE_ORDER == BIG_ENDIAN
54 uint32_t byte0, byte1, byte2, byte3;
55 #endif
56
57 #if BYTE_ORDER == BIG_ENDIAN
58 /*
59 * For BIG-ENDIAN platforms, the result is in LITTLE-ENDIAN byte
60 * order. For LITTLE-ENDIAN platforms, the result is in in
61 * BIG-ENDIAN byte order. So for BIG-ENDIAN platforms the bytes must
62 * be swapped to return the result always in network byte order (aka
63 * BIG-ENDIAN).
64 */
65 byte0 = crc32c & 0x000000ff;
66 byte1 = (crc32c >> 8) & 0x000000ff;
67 byte2 = (crc32c >> 16) & 0x000000ff;
68 byte3 = (crc32c >> 24) & 0x000000ff;
69 crc32c = ((byte0 << 24) | (byte1 << 16) | (byte2 << 8) | byte3);
70 #endif
71 return (~crc32c);
72 }
73
74 static int
sctp_calculate_cksum_cb(void * arg,void * data,u_int len)75 sctp_calculate_cksum_cb(void *arg, void *data, u_int len)
76 {
77 uint32_t *basep;
78
79 basep = arg;
80 *basep = calculate_crc32c(*basep, data, len);
81 return (0);
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
sctp_calculate_cksum(struct mbuf * m,int32_t offset)91 sctp_calculate_cksum(struct mbuf *m, int32_t offset)
92 {
93 uint32_t base;
94 int len;
95
96 M_ASSERTPKTHDR(m);
97 KASSERT(offset < m->m_pkthdr.len,
98 ("%s: invalid offset %u into mbuf %p", __func__, offset, m));
99
100 base = 0xffffffff;
101 len = m->m_pkthdr.len - offset;
102 (void)m_apply(m, offset, len, sctp_calculate_cksum_cb, &base);
103 return (sctp_finalize_crc32c(base));
104 }
105
106 #if defined(SCTP) || defined(SCTP_SUPPORT)
107
108 VNET_DEFINE(struct sctp_base_info, system_base_info);
109
110 /*
111 * Compute and insert the SCTP checksum in network byte order for a given
112 * mbuf chain m which contains an SCTP packet starting at offset.
113 */
114 void
sctp_delayed_cksum(struct mbuf * m,uint32_t offset)115 sctp_delayed_cksum(struct mbuf *m, uint32_t offset)
116 {
117 uint32_t checksum;
118
119 checksum = sctp_calculate_cksum(m, offset);
120 SCTP_STAT_DECR(sctps_sendhwcrc);
121 SCTP_STAT_INCR(sctps_sendswcrc);
122 offset += offsetof(struct sctphdr, checksum);
123
124 if (offset + sizeof(uint32_t) > (uint32_t)(m->m_pkthdr.len)) {
125 #ifdef INVARIANTS
126 panic("sctp_delayed_cksum(): m->m_pkthdr.len: %d, offset: %u.",
127 m->m_pkthdr.len, offset);
128 #else
129 SCTP_PRINTF("sctp_delayed_cksum(): m->m_pkthdr.len: %d, offset: %u.\n",
130 m->m_pkthdr.len, offset);
131 #endif
132 return;
133 }
134 m_copyback(m, (int)offset, (int)sizeof(uint32_t), (caddr_t)&checksum);
135 }
136 #endif
137