2 * Copyright (c) 2018 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:
7 * http://www.apache.org/licenses/LICENSE-2.0
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.
16 #ifndef __THROTTLE_H__
17 #define __THROTTLE_H__
19 #include <vlib/vlib.h>
23 * Used in the data plane to decide if a given hash should be throttled,
24 * i.e. that the hash has been seen already 'recently'. Recent is the time
25 * given in the throttle's initialisation.
27 typedef struct throttle_t_
32 f64 *last_seed_change_time;
35 #define THROTTLE_BITS (512)
37 extern void throttle_init (throttle_t * t, u32 n_threads, f64 time);
40 throttle_seed (throttle_t * t, u32 thread_index, f64 time_now)
42 if (time_now - t->last_seed_change_time[thread_index] > t->time)
44 (void) random_u32 (&t->seeds[thread_index]);
45 memset (t->bitmaps[thread_index], 0, THROTTLE_BITS / BITS (u8));
47 t->last_seed_change_time[thread_index] = time_now;
49 return t->seeds[thread_index];
53 throttle_check (throttle_t * t, u32 thread_index, u32 hash, u32 seed)
60 /* Select bit number */
61 hash &= THROTTLE_BITS - 1;
62 w = hash / BITS (uword);
63 m = (uword) 1 << (hash % BITS (uword));
65 drop = (t->bitmaps[thread_index][w] & m) != 0;
66 t->bitmaps[thread_index][w] |= m;
74 * fd.io coding-style-patch-verification: ON
77 * eval: (c-set-style "gnu")