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 <netinet/sctp_os.h> 39 #include <netinet/sctp.h> 40 #include <netinet/sctp_crc32.h> 41 #include <netinet/sctp_pcb.h> 42 43 44 #if !defined(SCTP_WITH_NO_CSUM) 45 46 static uint32_t 47 sctp_finalize_crc32c(uint32_t crc32c) 48 { 49 uint32_t result; 50 51 #if BYTE_ORDER == BIG_ENDIAN 52 uint8_t byte0, byte1, byte2, byte3; 53 54 #endif 55 /* Complement the result */ 56 result = ~crc32c; 57 #if BYTE_ORDER == BIG_ENDIAN 58 /* 59 * For BIG-ENDIAN.. aka Motorola byte order the result is in 60 * little-endian form. So we must manually swap the bytes. Then we 61 * can call htonl() which does nothing... 62 */ 63 byte0 = result & 0x000000ff; 64 byte1 = (result >> 8) & 0x000000ff; 65 byte2 = (result >> 16) & 0x000000ff; 66 byte3 = (result >> 24) & 0x000000ff; 67 crc32c = ((byte0 << 24) | (byte1 << 16) | (byte2 << 8) | byte3); 68 #else 69 /* 70 * For INTEL platforms the result comes out in network order. No 71 * htonl is required or the swap above. So we optimize out both the 72 * htonl and the manual swap above. 73 */ 74 crc32c = result; 75 #endif 76 return (crc32c); 77 } 78 79 uint32_t 80 sctp_calculate_cksum(struct mbuf *m, uint32_t offset) 81 { 82 /* 83 * given a mbuf chain with a packetheader offset by 'offset' 84 * pointing at a sctphdr (with csum set to 0) go through the chain 85 * of SCTP_BUF_NEXT()'s and calculate the SCTP checksum. This also 86 * has a side bonus as it will calculate the total length of the 87 * mbuf chain. Note: if offset is greater than the total mbuf 88 * length, checksum=1, pktlen=0 is returned (ie. no real error code) 89 */ 90 uint32_t base = 0xffffffff; 91 struct mbuf *at; 92 93 at = m; 94 /* find the correct mbuf and offset into mbuf */ 95 while ((at != NULL) && (offset > (uint32_t)SCTP_BUF_LEN(at))) { 96 offset -= SCTP_BUF_LEN(at); /* update remaining offset 97 * left */ 98 at = SCTP_BUF_NEXT(at); 99 } 100 while (at != NULL) { 101 if ((SCTP_BUF_LEN(at) - offset) > 0) { 102 base = calculate_crc32c(base, 103 (unsigned char *)(SCTP_BUF_AT(at, offset)), 104 (unsigned int)(SCTP_BUF_LEN(at) - offset)); 105 } 106 if (offset) { 107 /* we only offset once into the first mbuf */ 108 if (offset < (uint32_t)SCTP_BUF_LEN(at)) 109 offset = 0; 110 else 111 offset -= SCTP_BUF_LEN(at); 112 } 113 at = SCTP_BUF_NEXT(at); 114 } 115 base = sctp_finalize_crc32c(base); 116 return (base); 117 } 118 #endif /* !defined(SCTP_WITH_NO_CSUM) */ 119 120 121 void 122 sctp_delayed_cksum(struct mbuf *m, uint32_t offset) 123 { 124 #if defined(SCTP_WITH_NO_CSUM) 125 #ifdef INVARIANTS 126 panic("sctp_delayed_cksum() called when using no SCTP CRC."); 127 #endif 128 #else 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_len)) { 137 SCTP_PRINTF("sctp_delayed_cksum(): m->len: %d, off: %d.\n", 138 (uint32_t)m->m_len, offset); 139 /* 140 * XXX this shouldn't happen, but if it does, the correct 141 * behavior may be to insert the checksum in the appropriate 142 * next mbuf in the chain. 143 */ 144 return; 145 } 146 *(uint32_t *)(m->m_data + offset) = checksum; 147 #endif 148 } 149