freebsd-skq/sys/netinet/sctp_crc32.c
Pedro F. Giffuni 51369649b0 sys: further adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 3-Clause license.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.
2017-11-20 19:43:44 +00:00

149 lines
4.7 KiB
C

/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 2001-2007, by Cisco Systems, Inc. All rights reserved.
* Copyright (c) 2008-2012, by Randall Stewart. All rights reserved.
* Copyright (c) 2008-2012, by Michael Tuexen. 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.
*/
#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);
}
#endif /* !defined(SCTP_WITH_NO_CSUM) */
void
sctp_delayed_cksum(struct mbuf *m, uint32_t offset)
{
#if defined(SCTP_WITH_NO_CSUM)
#ifdef INVARIANTS
panic("sctp_delayed_cksum() called when using no SCTP CRC.");
#endif
#else
uint32_t checksum;
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)) {
SCTP_PRINTF("sctp_delayed_cksum(): m->len: %d, off: %d.\n",
(uint32_t)m->m_len, offset);
/*
* 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;
#endif
}