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 #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 147