1/*- 2 * Copyright (c) 2001-2007, by Cisco Systems, Inc. All rights reserved. 3 * Copyright (c) 2008-2012, by Randall Stewart. All rights reserved. 4 * Copyright (c) 2008-2012, by Michael Tuexen. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions are met: 8 * 9 * a) Redistributions of source code must retain the above copyright notice, 10 * this list of conditions and the following disclaimer. 11 * 12 * b) Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in 14 * the documentation and/or other materials provided with the distribution. 15 * 16 * c) Neither the name of Cisco Systems, Inc. nor the names of its 17 * contributors may be used to endorse or promote products derived 18 * from this software without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 21 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, 22 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 24 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF 30 * THE POSSIBILITY OF SUCH DAMAGE. 31 */ 32 33#include <sys/cdefs.h> 34__FBSDID("$FreeBSD: stable/11/sys/netinet/sctp_crc32.c 332229 2018-04-07 20:27:11Z tuexen $"); 35 36#include "opt_sctp.h" 37 38#ifdef SCTP 39#include <netinet/sctp_os.h> 40#include <netinet/sctp.h> 41#include <netinet/sctp_crc32.h> 42#include <netinet/sctp_pcb.h> 43#else 44#include <sys/param.h> 45#include <sys/systm.h> 46#include <sys/mbuf.h> 47 48#include <netinet/sctp_crc32.h> 49#endif 50 51static uint32_t 52sctp_finalize_crc32c(uint32_t crc32c) 53{ 54 uint32_t result; 55#if BYTE_ORDER == BIG_ENDIAN 56 uint8_t byte0, byte1, byte2, byte3; 57#endif 58 59 /* Complement the result */ 60 result = ~crc32c; 61#if BYTE_ORDER == BIG_ENDIAN 62 /* 63 * For BIG-ENDIAN platforms the result is in little-endian form. So 64 * we must swap the bytes to return the result in network byte 65 * order. 66 */ 67 byte0 = result & 0x000000ff; 68 byte1 = (result >> 8) & 0x000000ff; 69 byte2 = (result >> 16) & 0x000000ff; 70 byte3 = (result >> 24) & 0x000000ff; 71 crc32c = ((byte0 << 24) | (byte1 << 16) | (byte2 << 8) | byte3); 72#else 73 /* 74 * For LITTLE ENDIAN platforms the result is in already in network 75 * byte order. 76 */ 77 crc32c = result; 78#endif 79 return (crc32c); 80} 81 82/* 83 * Compute the SCTP checksum in network byte order for a given mbuf chain m 84 * which contains an SCTP packet starting at offset. 85 * Since this function is also called by ipfw, don't assume that 86 * it is compiled on a kernel with SCTP support. 87 */ 88uint32_t 89sctp_calculate_cksum(struct mbuf *m, uint32_t offset) 90{ 91 uint32_t base = 0xffffffff; 92 93 while (offset > 0) { 94 KASSERT(m != NULL, ("sctp_calculate_cksum, offset > length of mbuf chain")); 95 if (offset < (uint32_t)m->m_len) { 96 break; 97 } 98 offset -= m->m_len; 99 m = m->m_next; 100 } 101 if (offset > 0) { 102 base = calculate_crc32c(base, 103 (unsigned char *)(m->m_data + offset), 104 (unsigned int)(m->m_len - offset)); 105 m = m->m_next; 106 } 107 while (m != NULL) { 108 base = calculate_crc32c(base, 109 (unsigned char *)m->m_data, 110 (unsigned int)m->m_len); 111 m = m->m_next; 112 } 113 base = sctp_finalize_crc32c(base); 114 return (base); 115} 116 117#ifdef SCTP 118/* 119 * Compute and insert the SCTP checksum in network byte order for a given 120 * mbuf chain m which contains an SCTP packet starting at offset. 121 */ 122void 123sctp_delayed_cksum(struct mbuf *m, uint32_t offset) 124{ 125 uint32_t checksum; 126 127 checksum = sctp_calculate_cksum(m, offset); 128 SCTP_STAT_DECR(sctps_sendhwcrc); 129 SCTP_STAT_INCR(sctps_sendswcrc); 130 offset += offsetof(struct sctphdr, checksum); 131 132 if (offset + sizeof(uint32_t) > (uint32_t)(m->m_len)) { 133#ifdef INVARIANTS 134 panic("sctp_delayed_cksum(): m->m_len: %d, offset: %u.", 135 m->m_len, offset); 136#else 137 SCTP_PRINTF("sctp_delayed_cksum(): m->m_len: %d, offset: %u.\n", 138 m->m_len, offset); 139#endif 140 return; 141 } 142 *(uint32_t *)(m->m_data + offset) = checksum; 143} 144#endif 145