sctp_crc32.c revision 234996
1163953Srrs/*- 2169382Srrs * Copyright (c) 2001-2007, by Cisco Systems, Inc. All rights reserved. 3218319Srrs * Copyright (c) 2008-2011, by Randall Stewart. All rights reserved. 4218319Srrs * Copyright (c) 2008-2011, by Michael Tuexen. All rights reserved. 5163953Srrs * 6163953Srrs * Redistribution and use in source and binary forms, with or without 7163953Srrs * modification, are permitted provided that the following conditions are met: 8163953Srrs * 9163953Srrs * a) Redistributions of source code must retain the above copyright notice, 10163953Srrs * this list of conditions and the following disclaimer. 11163953Srrs * 12163953Srrs * b) Redistributions in binary form must reproduce the above copyright 13163953Srrs * notice, this list of conditions and the following disclaimer in 14163953Srrs * the documentation and/or other materials provided with the distribution. 15163953Srrs * 16163953Srrs * c) Neither the name of Cisco Systems, Inc. nor the names of its 17163953Srrs * contributors may be used to endorse or promote products derived 18163953Srrs * from this software without specific prior written permission. 19163953Srrs * 20163953Srrs * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 21163953Srrs * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, 22163953Srrs * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23163953Srrs * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 24163953Srrs * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 25163953Srrs * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 26163953Srrs * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 27163953Srrs * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 28163953Srrs * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 29163953Srrs * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF 30163953Srrs * THE POSSIBILITY OF SUCH DAMAGE. 31163953Srrs */ 32163953Srrs 33163953Srrs/* $KAME: sctp_crc32.c,v 1.12 2005/03/06 16:04:17 itojun Exp $ */ 34163953Srrs 35163953Srrs 36163953Srrs#include <sys/cdefs.h> 37163953Srrs__FBSDID("$FreeBSD: head/sys/netinet/sctp_crc32.c 234996 2012-05-04 10:06:08Z tuexen $"); 38163953Srrs 39191845Szec#include <netinet/sctp_os.h> 40188067Srrs#include <netinet/sctp.h> 41163953Srrs#include <netinet/sctp_crc32.h> 42188067Srrs#include <netinet/sctp_pcb.h> 43163953Srrs 44191891Srrs 45188067Srrs#if !defined(SCTP_WITH_NO_CSUM) 46163953Srrs 47163953Srrsstatic uint32_t 48188605Srrssctp_finalize_crc32c(uint32_t crc32c) 49163953Srrs{ 50163953Srrs uint32_t result; 51163953Srrs 52163953Srrs#if BYTE_ORDER == BIG_ENDIAN 53163953Srrs uint8_t byte0, byte1, byte2, byte3; 54163953Srrs 55163953Srrs#endif 56163953Srrs /* Complement the result */ 57168709Srrs result = ~crc32c; 58163953Srrs#if BYTE_ORDER == BIG_ENDIAN 59163953Srrs /* 60163953Srrs * For BIG-ENDIAN.. aka Motorola byte order the result is in 61163953Srrs * little-endian form. So we must manually swap the bytes. Then we 62163953Srrs * can call htonl() which does nothing... 63163953Srrs */ 64163953Srrs byte0 = result & 0x000000ff; 65163953Srrs byte1 = (result >> 8) & 0x000000ff; 66163953Srrs byte2 = (result >> 16) & 0x000000ff; 67163953Srrs byte3 = (result >> 24) & 0x000000ff; 68168709Srrs crc32c = ((byte0 << 24) | (byte1 << 16) | (byte2 << 8) | byte3); 69163953Srrs#else 70163953Srrs /* 71163953Srrs * For INTEL platforms the result comes out in network order. No 72163953Srrs * htonl is required or the swap above. So we optimize out both the 73163953Srrs * htonl and the manual swap above. 74163953Srrs */ 75168709Srrs crc32c = result; 76163953Srrs#endif 77168709Srrs return (crc32c); 78163953Srrs} 79188388Srrs 80188299Spisouint32_t 81188067Srrssctp_calculate_cksum(struct mbuf *m, uint32_t offset) 82188067Srrs{ 83188067Srrs /* 84188067Srrs * given a mbuf chain with a packetheader offset by 'offset' 85188067Srrs * pointing at a sctphdr (with csum set to 0) go through the chain 86188067Srrs * of SCTP_BUF_NEXT()'s and calculate the SCTP checksum. This also 87188067Srrs * has a side bonus as it will calculate the total length of the 88188067Srrs * mbuf chain. Note: if offset is greater than the total mbuf 89188067Srrs * length, checksum=1, pktlen=0 is returned (ie. no real error code) 90188067Srrs */ 91188067Srrs uint32_t base = 0xffffffff; 92188067Srrs struct mbuf *at; 93188067Srrs 94188067Srrs at = m; 95188067Srrs /* find the correct mbuf and offset into mbuf */ 96188067Srrs while ((at != NULL) && (offset > (uint32_t) SCTP_BUF_LEN(at))) { 97188067Srrs offset -= SCTP_BUF_LEN(at); /* update remaining offset 98188067Srrs * left */ 99188067Srrs at = SCTP_BUF_NEXT(at); 100188067Srrs } 101188067Srrs while (at != NULL) { 102188067Srrs if ((SCTP_BUF_LEN(at) - offset) > 0) { 103188605Srrs base = calculate_crc32c(base, 104188605Srrs (unsigned char *)(SCTP_BUF_AT(at, offset)), 105188605Srrs (unsigned int)(SCTP_BUF_LEN(at) - offset)); 106188067Srrs } 107188067Srrs if (offset) { 108188605Srrs /* we only offset once into the first mbuf */ 109188067Srrs if (offset < (uint32_t) SCTP_BUF_LEN(at)) 110188067Srrs offset = 0; 111188067Srrs else 112188067Srrs offset -= SCTP_BUF_LEN(at); 113188067Srrs } 114188067Srrs at = SCTP_BUF_NEXT(at); 115188067Srrs } 116188605Srrs base = sctp_finalize_crc32c(base); 117188067Srrs return (base); 118188067Srrs} 119188067Srrs 120188605Srrs#endif /* !defined(SCTP_WITH_NO_CSUM) */ 121188605Srrs 122188605Srrs 123188067Srrsvoid 124205104Srrssctp_delayed_cksum(struct mbuf *m, uint32_t offset) 125188067Srrs{ 126211969Stuexen#if defined(SCTP_WITH_NO_CSUM) 127234996Stuexen#ifdef INVARIANTS 128211969Stuexen panic("sctp_delayed_cksum() called when using no SCTP CRC."); 129234996Stuexen#endif 130211969Stuexen#else 131188067Srrs uint32_t checksum; 132188067Srrs 133188067Srrs checksum = sctp_calculate_cksum(m, offset); 134188067Srrs SCTP_STAT_DECR(sctps_sendhwcrc); 135188067Srrs SCTP_STAT_INCR(sctps_sendswcrc); 136188067Srrs offset += offsetof(struct sctphdr, checksum); 137188067Srrs 138188067Srrs if (offset + sizeof(uint32_t) > (uint32_t) (m->m_len)) { 139234995Stuexen SCTP_PRINTF("sctp_delayed_cksum(): m->len: %d, off: %d.\n", 140215301Stuexen (uint32_t) m->m_len, offset); 141188067Srrs /* 142188067Srrs * XXX this shouldn't happen, but if it does, the correct 143188067Srrs * behavior may be to insert the checksum in the appropriate 144188067Srrs * next mbuf in the chain. 145188067Srrs */ 146188067Srrs return; 147188067Srrs } 148188067Srrs *(uint32_t *) (m->m_data + offset) = checksum; 149211969Stuexen#endif 150188067Srrs} 151