1 /*- 2 * Copyright (c) 2001-2007, by Cisco Systems, Inc. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions are met: 6 * 7 * a) Redistributions of source code must retain the above copyright notice, 8 * this list of conditions and the following disclaimer. 9 * 10 * b) Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in 12 * the documentation and/or other materials provided with the distribution. 13 * 14 * c) Neither the name of Cisco Systems, Inc. nor the names of its 15 * contributors may be used to endorse or promote products derived 16 * from this software without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, 20 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 22 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 23 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 24 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 25 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 26 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 27 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF 28 * THE POSSIBILITY OF SUCH DAMAGE. 29 */ 30 31 /* $KAME: sctp_crc32.c,v 1.12 2005/03/06 16:04:17 itojun Exp $ */ 32 33 34 #include <sys/cdefs.h> 35 __FBSDID("$FreeBSD$"); 36 37 #include <sys/types.h> 38 #include <sys/socket.h> 39 #include <sys/socketvar.h> 40 #include <sys/uio.h> 41 #include <sys/libkern.h> 42 #include <netinet/sctp.h> 43 #include <netinet/sctp_crc32.h> 44 #include <netinet/sctp_pcb.h> 45 46 47 #if !defined(SCTP_WITH_NO_CSUM) 48 49 static uint32_t 50 sctp_finalize_crc32c(uint32_t crc32c) 51 { 52 uint32_t result; 53 54 #if BYTE_ORDER == BIG_ENDIAN 55 uint8_t byte0, byte1, byte2, byte3; 56 57 #endif 58 /* Complement the result */ 59 result = ~crc32c; 60 #if BYTE_ORDER == BIG_ENDIAN 61 /* 62 * For BIG-ENDIAN.. aka Motorola byte order the result is in 63 * little-endian form. So we must manually swap the bytes. Then we 64 * can call htonl() which does nothing... 65 */ 66 byte0 = result & 0x000000ff; 67 byte1 = (result >> 8) & 0x000000ff; 68 byte2 = (result >> 16) & 0x000000ff; 69 byte3 = (result >> 24) & 0x000000ff; 70 crc32c = ((byte0 << 24) | (byte1 << 16) | (byte2 << 8) | byte3); 71 #else 72 /* 73 * For INTEL platforms the result comes out in network order. No 74 * htonl is required or the swap above. So we optimize out both the 75 * htonl and the manual swap above. 76 */ 77 crc32c = result; 78 #endif 79 return (crc32c); 80 } 81 82 uint32_t 83 sctp_calculate_cksum(struct mbuf *m, uint32_t offset) 84 { 85 /* 86 * given a mbuf chain with a packetheader offset by 'offset' 87 * pointing at a sctphdr (with csum set to 0) go through the chain 88 * of SCTP_BUF_NEXT()'s and calculate the SCTP checksum. This also 89 * has a side bonus as it will calculate the total length of the 90 * mbuf chain. Note: if offset is greater than the total mbuf 91 * length, checksum=1, pktlen=0 is returned (ie. no real error code) 92 */ 93 uint32_t base = 0xffffffff; 94 struct mbuf *at; 95 96 at = m; 97 /* find the correct mbuf and offset into mbuf */ 98 while ((at != NULL) && (offset > (uint32_t) SCTP_BUF_LEN(at))) { 99 offset -= SCTP_BUF_LEN(at); /* update remaining offset 100 * left */ 101 at = SCTP_BUF_NEXT(at); 102 } 103 while (at != NULL) { 104 if ((SCTP_BUF_LEN(at) - offset) > 0) { 105 base = calculate_crc32c(base, 106 (unsigned char *)(SCTP_BUF_AT(at, offset)), 107 (unsigned int)(SCTP_BUF_LEN(at) - offset)); 108 } 109 if (offset) { 110 /* we only offset once into the first mbuf */ 111 if (offset < (uint32_t) SCTP_BUF_LEN(at)) 112 offset = 0; 113 else 114 offset -= SCTP_BUF_LEN(at); 115 } 116 at = SCTP_BUF_NEXT(at); 117 } 118 base = sctp_finalize_crc32c(base); 119 return (base); 120 } 121 122 #else 123 124 uint32_t 125 sctp_calculate_cksum(struct mbuf *m, uint32_t offset) 126 { 127 return (0); 128 } 129 130 #endif /* !defined(SCTP_WITH_NO_CSUM) */ 131 132 133 void 134 sctp_delayed_cksum(struct mbuf *m) 135 { 136 struct ip *ip; 137 uint32_t checksum; 138 uint32_t offset; 139 140 ip = mtod(m, struct ip *); 141 offset = ip->ip_hl << 2; 142 checksum = sctp_calculate_cksum(m, offset); 143 SCTP_STAT_DECR(sctps_sendhwcrc); 144 SCTP_STAT_INCR(sctps_sendswcrc); 145 offset += offsetof(struct sctphdr, checksum); 146 147 if (offset + sizeof(uint32_t) > (uint32_t) (m->m_len)) { 148 printf("delayed m_pullup, m->len: %d off: %d p: %d\n", 149 (uint32_t) m->m_len, offset, ip->ip_p); 150 /* 151 * XXX this shouldn't happen, but if it does, the correct 152 * behavior may be to insert the checksum in the appropriate 153 * next mbuf in the chain. 154 */ 155 return; 156 } 157 *(uint32_t *) (m->m_data + offset) = checksum; 158 } 159