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/*-
* Copyright (c) 2001-2007, by Cisco Systems, Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* a) Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* b) Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the distribution.
*
* c) Neither the name of Cisco Systems, Inc. nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*/
/* $KAME: sctp_crc32.c,v 1.12 2005/03/06 16:04:17 itojun Exp $ */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <netinet/sctp_os.h>
#include <netinet/sctp.h>
#include <netinet/sctp_crc32.h>
#include <netinet/sctp_pcb.h>
#if !defined(SCTP_WITH_NO_CSUM)
static uint32_t
sctp_finalize_crc32c(uint32_t crc32c)
{
uint32_t result;
#if BYTE_ORDER == BIG_ENDIAN
uint8_t byte0, byte1, byte2, byte3;
#endif
/* Complement the result */
result = ~crc32c;
#if BYTE_ORDER == BIG_ENDIAN
/*
* For BIG-ENDIAN.. aka Motorola byte order the result is in
* little-endian form. So we must manually swap the bytes. Then we
* can call htonl() which does nothing...
*/
byte0 = result & 0x000000ff;
byte1 = (result >> 8) & 0x000000ff;
byte2 = (result >> 16) & 0x000000ff;
byte3 = (result >> 24) & 0x000000ff;
crc32c = ((byte0 << 24) | (byte1 << 16) | (byte2 << 8) | byte3);
#else
/*
* For INTEL platforms the result comes out in network order. No
* htonl is required or the swap above. So we optimize out both the
* htonl and the manual swap above.
*/
crc32c = result;
#endif
return (crc32c);
}
uint32_t
sctp_calculate_cksum(struct mbuf *m, uint32_t offset)
{
/*
* given a mbuf chain with a packetheader offset by 'offset'
* pointing at a sctphdr (with csum set to 0) go through the chain
* of SCTP_BUF_NEXT()'s and calculate the SCTP checksum. This also
* has a side bonus as it will calculate the total length of the
* mbuf chain. Note: if offset is greater than the total mbuf
* length, checksum=1, pktlen=0 is returned (ie. no real error code)
*/
uint32_t base = 0xffffffff;
struct mbuf *at;
at = m;
/* find the correct mbuf and offset into mbuf */
while ((at != NULL) && (offset > (uint32_t) SCTP_BUF_LEN(at))) {
offset -= SCTP_BUF_LEN(at); /* update remaining offset
* left */
at = SCTP_BUF_NEXT(at);
}
while (at != NULL) {
if ((SCTP_BUF_LEN(at) - offset) > 0) {
base = calculate_crc32c(base,
(unsigned char *)(SCTP_BUF_AT(at, offset)),
(unsigned int)(SCTP_BUF_LEN(at) - offset));
}
if (offset) {
/* we only offset once into the first mbuf */
if (offset < (uint32_t) SCTP_BUF_LEN(at))
offset = 0;
else
offset -= SCTP_BUF_LEN(at);
}
at = SCTP_BUF_NEXT(at);
}
base = sctp_finalize_crc32c(base);
return (base);
}
#else
uint32_t
sctp_calculate_cksum(struct mbuf *m, uint32_t offset)
{
return (0);
}
#endif /* !defined(SCTP_WITH_NO_CSUM) */
void
sctp_delayed_cksum(struct mbuf *m)
{
struct ip *ip;
uint32_t checksum;
uint32_t offset;
ip = mtod(m, struct ip *);
offset = ip->ip_hl << 2;
checksum = sctp_calculate_cksum(m, offset);
SCTP_STAT_DECR(sctps_sendhwcrc);
SCTP_STAT_INCR(sctps_sendswcrc);
offset += offsetof(struct sctphdr, checksum);
if (offset + sizeof(uint32_t) > (uint32_t) (m->m_len)) {
printf("delayed m_pullup, m->len: %d off: %d p: %d\n",
(uint32_t) m->m_len, offset, ip->ip_p);
/*
* XXX this shouldn't happen, but if it does, the correct
* behavior may be to insert the checksum in the appropriate
* next mbuf in the chain.
*/
return;
}
*(uint32_t *) (m->m_data + offset) = checksum;
}
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