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/*
* feat_bitmap.h: bitmap for managing feature invocation
*
* Copyright (c) 2013 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 included_vnet_l2_feat_bitmap_h
#define included_vnet_l2_feat_bitmap_h
#include <vlib/vlib.h>
#include <vnet/vnet.h>
/*
* The feature bitmap is a way of organizing input and output feature graph nodes.
* The set of features to be executed are arranged in a bitmap with one bit per
* feature and each bit positioned in the same order that the features should be
* executed. Features can be dynamically removed from the set by masking off their
* corresponding bits. The bitmap is stored in packet context. Each feature clears
* its bit and then calls feat_bitmap_get_next_node_index() to go to the next
* graph node.
*/
// 32 features in a u32 bitmap
#define FEAT_MAX 32
// Initialize the feature next-node indexes of a graph node.
// Should be called by the init function of each feature graph node.
always_inline
void feat_bitmap_init_next_nodes (
vlib_main_t * vm,
u32 node_index, // the current graph node index
u32 num_features, // number of entries in feat_names
char ** feat_names, // array of feature graph node names
u32 * next_nodes) // array of 32 next indexes to init
{
u32 idx;
ASSERT(num_features <= FEAT_MAX);
for (idx=0; idx<num_features; idx++) {
if (vlib_get_node_by_name(vm, (u8 *) feat_names[idx])) {
next_nodes[idx] =
vlib_node_add_named_next(vm, node_index, feat_names[idx]);
} else { // Node may be in plugin which is not installed, use drop node
next_nodes[idx] =
vlib_node_add_named_next(vm, node_index, "feature-bitmap-drop");
}
}
// All unassigned bits go to the drop node
for (; idx<FEAT_MAX; idx++) {
next_nodes[idx] = vlib_node_add_named_next(vm, node_index, "feature-bitmap-drop");
}
}
// Return the graph node index for the feature corresponding to the
// first set bit in the bitmap.
always_inline
u32 feat_bitmap_get_next_node_index (u32 * next_nodes, u32 bitmap)
{
u32 first_bit;
count_leading_zeros(first_bit, bitmap);
first_bit = uword_bits - 1 - first_bit;
return next_nodes[first_bit];
}
#endif // included_vnet_l2_feat_bitmap_h
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