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-rw-r--r--src/vnet/util/throttle.c38
-rw-r--r--src/vnet/util/throttle.h79
2 files changed, 117 insertions, 0 deletions
diff --git a/src/vnet/util/throttle.c b/src/vnet/util/throttle.c
new file mode 100644
index 00000000000..0985b4a81a3
--- /dev/null
+++ b/src/vnet/util/throttle.c
@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) 2018 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.
+ */
+
+#include <vnet/util/throttle.h>
+
+void
+throttle_init (throttle_t * t, u32 n_threads, f64 time)
+{
+ u32 i;
+
+ t->time = time;
+ vec_validate (t->bitmaps, n_threads);
+ vec_validate (t->seeds, n_threads);
+ vec_validate (t->last_seed_change_time, n_threads);
+
+ for (i = 0; i < n_threads; i++)
+ vec_validate (t->bitmaps[i], (THROTTLE_BITS / BITS (uword)) - 1);
+}
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
diff --git a/src/vnet/util/throttle.h b/src/vnet/util/throttle.h
new file mode 100644
index 00000000000..0c518d3555b
--- /dev/null
+++ b/src/vnet/util/throttle.h
@@ -0,0 +1,79 @@
+/*
+ * Copyright (c) 2018 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.
+ */
+
+#ifndef __THROTTLE_H__
+#define __THROTTLE_H__
+
+#include <vlib/vlib.h>
+
+/**
+ * @brief A throttle
+ * Used in the data plane to decide if a given hash should be throttled,
+ * i.e. that the hash has been seen alreay 'recently'. Recent is the time
+ * given in the throttle's initialisation.
+ */
+typedef struct throttle_t_
+{
+ f64 time;
+ uword **bitmaps;
+ u32 *seeds;
+ f64 *last_seed_change_time;
+} throttle_t;
+
+#define THROTTLE_BITS (512)
+
+extern void throttle_init (throttle_t * t, u32 n_threads, f64 time);
+
+always_inline u32
+throttle_seed (throttle_t * t, u32 thread_index, f64 time_now)
+{
+ if (time_now - t->last_seed_change_time[thread_index] > t->time)
+ {
+ (void) random_u32 (&t->seeds[thread_index]);
+ memset (t->bitmaps[thread_index], 0, THROTTLE_BITS / BITS (u8));
+
+ t->last_seed_change_time[thread_index] = time_now;
+ }
+ return t->seeds[thread_index];
+}
+
+always_inline int
+throttle_check (throttle_t * t, u32 thread_index, u32 hash, u32 seed)
+{
+ int drop;
+ uword m;
+ u32 w;
+
+ hash ^= seed;
+ /* Select bit number */
+ hash &= THROTTLE_BITS - 1;
+ w = hash / BITS (uword);
+ m = (uword) 1 << (hash % BITS (uword));
+
+ drop = (t->bitmaps[thread_index][w] & m) != 0;
+ t->bitmaps[thread_index][w] |= m;
+
+ return (drop);
+}
+
+#endif
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */