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/*
* Copyright (c) 2015 Cisco and/or its affiliates.
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/*
* ip4/ip_checksum.c: ip/tcp/udp checksums
*
* Copyright (c) 2008 Eliot Dresselhaus
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#include <vnet/ip/ip.h>
static ip_csum_t
_ip_incremental_checksum (ip_csum_t sum, void *_data, uword n_bytes)
{
uword data = pointer_to_uword (_data);
ip_csum_t sum0, sum1;
sum0 = 0;
sum1 = sum;
/*
* Align pointer to 64 bits. The ip checksum is a 16-bit
* one's complememt sum. It's impractical to optimize
* the calculation if the incoming address is odd.
*/
#define _(t) \
do { \
if (n_bytes >= sizeof (t) \
&& sizeof (t) < sizeof (ip_csum_t) \
&& (data % (2 * sizeof (t))) != 0) \
{ \
sum0 += * uword_to_pointer (data, t *); \
data += sizeof (t); \
n_bytes -= sizeof (t); \
} \
} while (0)
if (PREDICT_TRUE ((data & 1) == 0))
{
_(u16);
if (BITS (ip_csum_t) > 32)
_(u32);
}
#undef _
{
ip_csum_t *d = uword_to_pointer (data, ip_csum_t *);
while (n_bytes >= 2 * sizeof (d[0]))
{
sum0 = ip_csum_with_carry (sum0, d[0]);
sum1 = ip_csum_with_carry (sum1, d[1]);
d += 2;
n_bytes -= 2 * sizeof (d[0]);
}
data = pointer_to_uword (d);
}
#define _(t) \
do { \
if (n_bytes >= sizeof (t) && sizeof (t) <= sizeof (ip_csum_t)) \
{ \
sum0 = ip_csum_with_carry (sum0, * uword_to_pointer (data, t *)); \
data += sizeof (t); \
n_bytes -= sizeof (t); \
} \
} while (0)
if (BITS (ip_csum_t) > 32)
_(u64);
_(u32);
_(u16);
_(u8);
#undef _
/* Combine even and odd sums. */
sum0 = ip_csum_with_carry (sum0, sum1);
return sum0;
}
/*
* Note: the tcp / udp checksum calculation is performance critical
* [e.g. when NIC h/w offload is not available],
* so it's worth producing architecture-dependent code.
*
* ip_incremental_checksum() is an always-inlined static
* function which uses the function pointer we set up in
* ip_checksum_init().
*/
ip_csum_t (*vnet_incremental_checksum_fp) (ip_csum_t, void *, uword);
static clib_error_t *
ip_checksum_init (vlib_main_t * vm)
{
vnet_incremental_checksum_fp = _ip_incremental_checksum;
return 0;
}
VLIB_INIT_FUNCTION (ip_checksum_init);
#if CLIB_DEBUG > 0
static const char test_pkt[] = {
0x45, 0x00, 0x00, 0x3c, 0x5d, 0x6f, 0x40, 0x00,
0x40, 0x06, 0x3f, 0x6b, 0x0a, 0x76, 0x72, 0x44,
0x0a, 0x56, 0x16, 0xd2,
};
static clib_error_t *
test_ip_checksum_fn (vlib_main_t * vm,
unformat_input_t * input, vlib_cli_command_t * cmd)
{
u16 csum;
ip4_header_t *hp;
u8 *align_test = 0;
int offset;
vec_validate (align_test, ARRAY_LEN (test_pkt) + 7);
for (offset = 0; offset < 8; offset++)
{
memcpy (align_test + offset, test_pkt, ARRAY_LEN (test_pkt));
hp = (ip4_header_t *) (align_test + offset);
csum = ip4_header_checksum (hp);
vlib_cli_output (vm, "offset %d checksum %u expected result 27455",
offset, (u32) csum);
}
return 0;
}
/* *INDENT-OFF* */
VLIB_CLI_COMMAND (test_checksum, static) =
{
.path = "test ip checksum",
.short_help = "test ip checksum",
.function = test_ip_checksum_fn,
};
/* *INDENT-ON* */
#endif /* CLIB_DEBUG */
/*
* fd.io coding-style-patch-verification: ON
*
* Local Variables:
* eval: (c-set-style "gnu")
* End:
*/
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