147 lines
4.6 KiB
C
147 lines
4.6 KiB
C
/*-
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* Copyright (c) 2001-2007, by Cisco Systems, Inc. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* a) Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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*
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* b) Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the distribution.
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*
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* c) Neither the name of Cisco Systems, Inc. nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
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* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
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* THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/* $KAME: sctp_crc32.c,v 1.12 2005/03/06 16:04:17 itojun Exp $ */
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <netinet/sctp_os.h>
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#include <netinet/sctp.h>
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#include <netinet/sctp_crc32.h>
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#include <netinet/sctp_pcb.h>
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#if !defined(SCTP_WITH_NO_CSUM)
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static uint32_t
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sctp_finalize_crc32c(uint32_t crc32c)
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{
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uint32_t result;
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#if BYTE_ORDER == BIG_ENDIAN
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uint8_t byte0, byte1, byte2, byte3;
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#endif
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/* Complement the result */
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result = ~crc32c;
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#if BYTE_ORDER == BIG_ENDIAN
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/*
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* For BIG-ENDIAN.. aka Motorola byte order the result is in
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* little-endian form. So we must manually swap the bytes. Then we
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* can call htonl() which does nothing...
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*/
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byte0 = result & 0x000000ff;
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byte1 = (result >> 8) & 0x000000ff;
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byte2 = (result >> 16) & 0x000000ff;
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byte3 = (result >> 24) & 0x000000ff;
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crc32c = ((byte0 << 24) | (byte1 << 16) | (byte2 << 8) | byte3);
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#else
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/*
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* For INTEL platforms the result comes out in network order. No
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* htonl is required or the swap above. So we optimize out both the
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* htonl and the manual swap above.
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*/
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crc32c = result;
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#endif
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return (crc32c);
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}
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uint32_t
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sctp_calculate_cksum(struct mbuf *m, uint32_t offset)
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{
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/*
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* given a mbuf chain with a packetheader offset by 'offset'
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* pointing at a sctphdr (with csum set to 0) go through the chain
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* of SCTP_BUF_NEXT()'s and calculate the SCTP checksum. This also
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* has a side bonus as it will calculate the total length of the
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* mbuf chain. Note: if offset is greater than the total mbuf
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* length, checksum=1, pktlen=0 is returned (ie. no real error code)
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*/
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uint32_t base = 0xffffffff;
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struct mbuf *at;
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at = m;
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/* find the correct mbuf and offset into mbuf */
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while ((at != NULL) && (offset > (uint32_t) SCTP_BUF_LEN(at))) {
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offset -= SCTP_BUF_LEN(at); /* update remaining offset
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* left */
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at = SCTP_BUF_NEXT(at);
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}
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while (at != NULL) {
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if ((SCTP_BUF_LEN(at) - offset) > 0) {
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base = calculate_crc32c(base,
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(unsigned char *)(SCTP_BUF_AT(at, offset)),
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(unsigned int)(SCTP_BUF_LEN(at) - offset));
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}
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if (offset) {
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/* we only offset once into the first mbuf */
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if (offset < (uint32_t) SCTP_BUF_LEN(at))
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offset = 0;
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else
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offset -= SCTP_BUF_LEN(at);
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}
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at = SCTP_BUF_NEXT(at);
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}
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base = sctp_finalize_crc32c(base);
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return (base);
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}
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#endif /* !defined(SCTP_WITH_NO_CSUM) */
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void
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sctp_delayed_cksum(struct mbuf *m, uint32_t offset)
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{
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#if defined(SCTP_WITH_NO_CSUM)
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panic("sctp_delayed_cksum() called when using no SCTP CRC.");
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#else
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uint32_t checksum;
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checksum = sctp_calculate_cksum(m, offset);
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SCTP_STAT_DECR(sctps_sendhwcrc);
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SCTP_STAT_INCR(sctps_sendswcrc);
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offset += offsetof(struct sctphdr, checksum);
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if (offset + sizeof(uint32_t) > (uint32_t) (m->m_len)) {
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printf("sctp_delayed_cksum(): m->len: %d, off: %d.\n",
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(uint32_t) m->m_len, offset);
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/*
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* XXX this shouldn't happen, but if it does, the correct
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* behavior may be to insert the checksum in the appropriate
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* next mbuf in the chain.
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*/
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return;
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}
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*(uint32_t *) (m->m_data + offset) = checksum;
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#endif
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}
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