diff options
Diffstat (limited to 'vnet/vnet/l2/feat_bitmap.h')
-rw-r--r-- | vnet/vnet/l2/feat_bitmap.h | 80 |
1 files changed, 80 insertions, 0 deletions
diff --git a/vnet/vnet/l2/feat_bitmap.h b/vnet/vnet/l2/feat_bitmap.h new file mode 100644 index 00000000000..7dd36a7712e --- /dev/null +++ b/vnet/vnet/l2/feat_bitmap.h @@ -0,0 +1,80 @@ +/* + * 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 |