42e2140dd9
When using cached bytes: - do not overflow - do not return the same bytes twice Type: fix Change-Id: I2a87b47a79300e56a2201b8fc3cb6cb15b592e28 Signed-off-by: Benoît Ganne <bganne@cisco.com>
128 lines
3.6 KiB
C
128 lines
3.6 KiB
C
/*
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* Copyright (c) 2015 Cisco and/or its affiliates.
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/*
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Copyright (c) 2005 Eliot Dresselhaus
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Permission is hereby granted, free of charge, to any person obtaining
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a copy of this software and associated documentation files (the
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"Software"), to deal in the Software without restriction, including
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without limitation the rights to use, copy, modify, merge, publish,
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distribute, sublicense, and/or sell copies of the Software, and to
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permit persons to whom the Software is furnished to do so, subject to
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the following conditions:
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The above copyright notice and this permission notice shall be
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included in all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
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LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
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OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
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WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*/
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#ifndef included_clib_random_buffer_h
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#define included_clib_random_buffer_h
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#include <vppinfra/clib.h>
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#include <vppinfra/random_isaac.h>
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#include <vppinfra/warnings.h>
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/* *INDENT-OFF* */
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WARN_OFF(array-bounds)
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/* *INDENT-ON* */
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typedef struct
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{
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/* Two parallel ISAAC contexts for speed. */
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isaac_t ctx[2];
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/* Random buffer. */
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uword *buffer;
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/* Cache up to 1 word worth of bytes for random data
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less than one word at a time. */
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uword n_cached_bytes;
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union
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{
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u8 cached_bytes[sizeof (uword)];
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uword cached_word;
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};
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}
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clib_random_buffer_t;
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always_inline void
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clib_random_buffer_free (clib_random_buffer_t * b)
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{
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vec_free (b->buffer);
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}
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/* Fill random buffer. */
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void clib_random_buffer_fill (clib_random_buffer_t * b, uword n_words);
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/* Initialize random buffer. */
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void clib_random_buffer_init (clib_random_buffer_t * b, uword seed);
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/* Returns word aligned random data, possibly filling buffer. */
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always_inline void *
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clib_random_buffer_get_data (clib_random_buffer_t * b, uword n_bytes)
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{
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uword n_words, i, l;
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l = b->n_cached_bytes;
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if (n_bytes <= l)
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{
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b->n_cached_bytes = l - n_bytes;
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return &b->cached_bytes[l - n_bytes];
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}
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n_words = n_bytes / sizeof (uword);
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if (n_bytes % sizeof (uword))
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n_words++;
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/* Enough random words left? */
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if (PREDICT_FALSE (n_words > vec_len (b->buffer)))
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clib_random_buffer_fill (b, n_words);
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i = vec_len (b->buffer) - n_words;
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_vec_len (b->buffer) = i;
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if (n_bytes < sizeof (uword))
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{
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b->cached_word = b->buffer[i];
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b->n_cached_bytes = sizeof (uword) - n_bytes;
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return &b->cached_bytes[sizeof (uword) - n_bytes];
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}
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else
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return b->buffer + i;
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}
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/* *INDENT-OFF* */
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WARN_ON(array-bounds)
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/* *INDENT-ON* */
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#endif /* included_clib_random_buffer_h */
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/*
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* fd.io coding-style-patch-verification: ON
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*
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* Local Variables:
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* eval: (c-set-style "gnu")
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* End:
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*/
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