Line data    Source code

       1             : /*
       2             :  * Copyright (c) 2015 Cisco and/or its affiliates.
       3             :  * Licensed under the Apache License, Version 2.0 (the "License");
       4             :  * you may not use this file except in compliance with the License.
       5             :  * You may obtain a copy of the License at:
       6             :  *
       7             :  *     http://www.apache.org/licenses/LICENSE-2.0
       8             :  *
       9             :  * Unless required by applicable law or agreed to in writing, software
      10             :  * distributed under the License is distributed on an "AS IS" BASIS,
      11             :  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
      12             :  * See the License for the specific language governing permissions and
      13             :  * limitations under the License.
      14             :  */
      15             : /*
      16             :   Copyright (c) 2005 Eliot Dresselhaus
      17             : 
      18             :   Permission is hereby granted, free of charge, to any person obtaining
      19             :   a copy of this software and associated documentation files (the
      20             :   "Software"), to deal in the Software without restriction, including
      21             :   without limitation the rights to use, copy, modify, merge, publish,
      22             :   distribute, sublicense, and/or sell copies of the Software, and to
      23             :   permit persons to whom the Software is furnished to do so, subject to
      24             :   the following conditions:
      25             : 
      26             :   The above copyright notice and this permission notice shall be
      27             :   included in all copies or substantial portions of the Software.
      28             : 
      29             :   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
      30             :   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
      31             :   MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
      32             :   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
      33             :   LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
      34             :   OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
      35             :   WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
      36             : */
      37             : 
      38             : #ifndef included_clib_random_buffer_h
      39             : #define included_clib_random_buffer_h
      40             : 
      41             : #include <vppinfra/clib.h>
      42             : #include <vppinfra/random_isaac.h>
      43             : #include <vppinfra/warnings.h>
      44             : 
      45             : /* *INDENT-OFF* */
      46             : WARN_OFF(array-bounds)
      47             : /* *INDENT-ON* */
      48             : 
      49             : typedef struct
      50             : {
      51             :   /* Two parallel ISAAC contexts for speed. */
      52             :   isaac_t ctx[2];
      53             : 
      54             :   /* Random buffer. */
      55             :   uword *buffer;
      56             : 
      57             :   /* An actual length to be applied before using the buffer. */
      58             :   uword next_read_len;
      59             : 
      60             :   /* Cache up to 1 word worth of bytes for random data
      61             :      less than one word at a time. */
      62             :   uword n_cached_bytes;
      63             : 
      64             :   union
      65             :   {
      66             :     u8 cached_bytes[sizeof (uword)];
      67             :     uword cached_word;
      68             :   };
      69             : }
      70             : clib_random_buffer_t;
      71             : 
      72             : always_inline void
      73           1 : clib_random_buffer_free (clib_random_buffer_t * b)
      74             : {
      75           1 :   vec_free (b->buffer);
      76           1 : }
      77             : 
      78             : /* Fill random buffer. */
      79             : void clib_random_buffer_fill (clib_random_buffer_t * b, uword n_words);
      80             : 
      81             : /* Initialize random buffer. */
      82             : void clib_random_buffer_init (clib_random_buffer_t * b, uword seed);
      83             : 
      84             : /* Returns word aligned random data, possibly filling buffer. */
      85             : always_inline void *
      86       10255 : clib_random_buffer_get_data (clib_random_buffer_t * b, uword n_bytes)
      87             : {
      88             :   uword n_words, i, l;
      89             : 
      90       10255 :   if (b->buffer)
      91       10084 :     vec_set_len (b->buffer, b->next_read_len);
      92             :   else
      93         171 :     ASSERT (b->next_read_len == 0);
      94             : 
      95       10255 :   l = b->n_cached_bytes;
      96       10255 :   if (n_bytes <= l)
      97             :     {
      98        2883 :       b->n_cached_bytes = l - n_bytes;
      99        2883 :       return &b->cached_bytes[l - n_bytes];
     100             :     }
     101             : 
     102        7372 :   n_words = n_bytes / sizeof (uword);
     103        7372 :   if (n_bytes % sizeof (uword))
     104        6377 :     n_words++;
     105             : 
     106             :   /* Enough random words left? */
     107        7372 :   if (PREDICT_FALSE (n_words > vec_len (b->buffer)))
     108        1724 :     clib_random_buffer_fill (b, n_words);
     109             : 
     110        7372 :   i = vec_len (b->buffer) - n_words;
     111        7372 :   b->next_read_len = i;
     112             : 
     113        7372 :   if (n_bytes < sizeof (uword))
     114             :     {
     115        2388 :       b->cached_word = b->buffer[i];
     116        2388 :       b->n_cached_bytes = sizeof (uword) - n_bytes;
     117        2388 :       return &b->cached_bytes[sizeof (uword) - n_bytes];
     118             :     }
     119             :   else
     120        4984 :     return b->buffer + i;
     121             : }
     122             : 
     123             : /* *INDENT-OFF* */
     124             : WARN_ON(array-bounds)
     125             : /* *INDENT-ON* */
     126             : 
     127             : #endif /* included_clib_random_buffer_h */
     128             : 
     129             : /*
     130             :  * fd.io coding-style-patch-verification: ON
     131             :  *
     132             :  * Local Variables:
     133             :  * eval: (c-set-style "gnu")
     134             :  * End:
     135             :  */