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("$FreeBSD$"); 35 36 #include <netinet/sctp_os.h> 37 #include <netinet/sctp.h> 38 #include <netinet/sctp_crc32.h> 39 #include <netinet/sctp_pcb.h> 40 41 42 #if !defined(SCTP_WITH_NO_CSUM) 43 44 static uint32_t 45 sctp_finalize_crc32c(uint32_t crc32c) 46 { 47 uint32_t result; 48 49 #if BYTE_ORDER == BIG_ENDIAN 50 uint8_t byte0, byte1, byte2, byte3; 51 52 #endif 53 /* Complement the result */ 54 result = ~crc32c; 55 #if BYTE_ORDER == BIG_ENDIAN 56 /* 57 * For BIG-ENDIAN.. aka Motorola byte order the result is in 58 * little-endian form. So we must manually swap the bytes. Then we 59 * can call htonl() which does nothing... 60 */ 61 byte0 = result & 0x000000ff; 62 byte1 = (result >> 8) & 0x000000ff; 63 byte2 = (result >> 16) & 0x000000ff; 64 byte3 = (result >> 24) & 0x000000ff; 65 crc32c = ((byte0 << 24) | (byte1 << 16) | (byte2 << 8) | byte3); 66 #else 67 /* 68 * For INTEL platforms the result comes out in network order. No 69 * htonl is required or the swap above. So we optimize out both the 70 * htonl and the manual swap above. 71 */ 72 crc32c = result; 73 #endif 74 return (crc32c); 75 } 76 77 uint32_t 78 sctp_calculate_cksum(struct mbuf *m, uint32_t offset) 79 { 80 /* 81 * given a mbuf chain with a packetheader offset by 'offset' 82 * pointing at a sctphdr (with csum set to 0) go through the chain 83 * of SCTP_BUF_NEXT()'s and calculate the SCTP checksum. This also 84 * has a side bonus as it will calculate the total length of the 85 * mbuf chain. Note: if offset is greater than the total mbuf 86 * length, checksum=1, pktlen=0 is returned (ie. no real error code) 87 */ 88 uint32_t base = 0xffffffff; 89 struct mbuf *at; 90 91 at = m; 92 /* find the correct mbuf and offset into mbuf */ 93 while ((at != NULL) && (offset > (uint32_t) SCTP_BUF_LEN(at))) { 94 offset -= SCTP_BUF_LEN(at); /* update remaining offset 95 * left */ 96 at = SCTP_BUF_NEXT(at); 97 } 98 while (at != NULL) { 99 if ((SCTP_BUF_LEN(at) - offset) > 0) { 100 base = calculate_crc32c(base, 101 (unsigned char *)(SCTP_BUF_AT(at, offset)), 102 (unsigned int)(SCTP_BUF_LEN(at) - offset)); 103 } 104 if (offset) { 105 /* we only offset once into the first mbuf */ 106 if (offset < (uint32_t) SCTP_BUF_LEN(at)) 107 offset = 0; 108 else 109 offset -= SCTP_BUF_LEN(at); 110 } 111 at = SCTP_BUF_NEXT(at); 112 } 113 base = sctp_finalize_crc32c(base); 114 return (base); 115 } 116 117 #endif /* !defined(SCTP_WITH_NO_CSUM) */ 118 119 120 void 121 sctp_delayed_cksum(struct mbuf *m, uint32_t offset) 122 { 123 #if defined(SCTP_WITH_NO_CSUM) 124 #ifdef INVARIANTS 125 panic("sctp_delayed_cksum() called when using no SCTP CRC."); 126 #endif 127 #else 128 uint32_t checksum; 129 130 checksum = sctp_calculate_cksum(m, offset); 131 SCTP_STAT_DECR(sctps_sendhwcrc); 132 SCTP_STAT_INCR(sctps_sendswcrc); 133 offset += offsetof(struct sctphdr, checksum); 134 135 if (offset + sizeof(uint32_t) > (uint32_t) (m->m_len)) { 136 SCTP_PRINTF("sctp_delayed_cksum(): m->len: %d, off: %d.\n", 137 (uint32_t) m->m_len, offset); 138 /* 139 * XXX this shouldn't happen, but if it does, the correct 140 * behavior may be to insert the checksum in the appropriate 141 * next mbuf in the chain. 142 */ 143 return; 144 } 145 *(uint32_t *) (m->m_data + offset) = checksum; 146 #endif 147 } 148