acl-plugin: bihash-based ACL lookup

Add a bihash-based ACL lookup mechanism and make it a new default.
This changes the time required to lookup a 5-tuple match
from O(total_N_entries) to O(total_N_mask_types), where
"mask type" is an overall mask on the 5-tuple required
to represent an ACE.

For testing/comparison there is a temporary debug CLI
"set acl-plugin use-hash-acl-matching {0|1}", which,
when set to 0, makes the plugin use the "old" linear lookup,
and when set to 1, makes it use the hash-based lookup.

Based on the discussions on vpp-dev mailing list,
prevent assigning the ACL index to an interface,
when the ACL with that index is not defined,
also prevent deleting an ACL if that ACL is applied.

Also, for the easier debugging of the state, there are
new debug CLI commands to see the ACL plugin state at
several layers:

"show acl-plugin acl [index N]" - show a high-level
ACL representation, used for the linear lookup and
as a base for building the hashtable-based lookup.
Also shows if a given ACL is applied somewhere.

"show acl-plugin interface [sw_if_index N]" - show
which interfaces have which ACL(s) applied.

"show acl-plugin tables" - a lower-level debug command
used to see the state of all of the related data structures
at once. There are specifiers possible, which make
for a more focused and maybe augmented output:

"show acl-plugin tables acl [index N]"
show the "bitmask-ready" representations of the ACLs,
we well as the mask types and their associated indices.

"show acl-plutin tables mask"
show the derived mask types and their indices only.

"show acl-plugin tables applied [sw_if_index N]"
show the table of all of the ACEs applied for a given
sw_if_index or all interfaces.

"show acl-plugin tables hash [verbose N]"
show the 48x8 bihash used for the ACL lookup.

Change-Id: I89fff051424cb44bcb189e3cee04c1b8f76efc28
Signed-off-by: Andrew Yourtchenko <ayourtch@gmail.com>

1 files changed, 742 insertions, 0 deletions

diff --git a/src/plugins/acl/hash_lookup.c b/src/plugins/acl/hash_lookup.c
new file mode 100644
index 00000000000..8e8c52740ee
--- /dev/null
+++ b/src/plugins/acl/hash_lookup.c
@@ -0,0 +1,742 @@
+/*
+ *------------------------------------------------------------------
+ * Copyright (c) 2017 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 <stddef.h>
+#include <netinet/in.h>
+
+#include <vlibapi/api.h>
+#include <vlibmemory/api.h>
+#include <vlibsocket/api.h>
+
+#include <vlib/vlib.h>
+#include <vnet/vnet.h>
+#include <vnet/pg/pg.h>
+#include <vppinfra/error.h>
+#include <vnet/plugin/plugin.h>
+#include <acl/acl.h>
+#include <vppinfra/bihash_48_8.h>
+
+#include "hash_lookup.h"
+#include "hash_lookup_private.h"
+
+/*
+ * This returns true if there is indeed a match on the portranges.
+ * With all these levels of indirections, this is not going to be very fast,
+ * so, best use the individual ports or wildcard ports for performance.
+ */
+static int
+match_portranges(acl_main_t *am, fa_5tuple_t *match, u32 index)
+{
+  applied_hash_ace_entry_t **applied_hash_aces = match->pkt.is_input ? &am->input_hash_entry_vec_by_sw_if_index[match->pkt.sw_if_index] :
+                                                    &am->output_hash_entry_vec_by_sw_if_index[match->pkt.sw_if_index];
+  applied_hash_ace_entry_t *pae = &((*applied_hash_aces)[index]);
+
+  // hash_acl_info_t *ha = &am->hash_acl_infos[pae->acl_index];
+  acl_rule_t *r = &(am->acls[pae->acl_index].rules[pae->ace_index]);
+  DBG("PORTMATCH: %d <= %d <= %d && %d <= %d <= %d ?",
+		r->src_port_or_type_first, match->l4.port[0], r->src_port_or_type_last,
+		r->dst_port_or_code_first, match->l4.port[1], r->dst_port_or_code_last);
+
+  return ( ((r->src_port_or_type_first <= match->l4.port[0]) && r->src_port_or_type_last >= match->l4.port[0]) &&
+           ((r->dst_port_or_code_first <= match->l4.port[1]) && r->dst_port_or_code_last >= match->l4.port[1]) );
+}
+
+static u32
+multi_acl_match_get_applied_ace_index(acl_main_t *am, fa_5tuple_t *match)
+{
+  clib_bihash_kv_48_8_t kv;
+  clib_bihash_kv_48_8_t result;
+  fa_5tuple_t *kv_key = (fa_5tuple_t *)kv.key;
+  hash_acl_lookup_value_t *result_val = (hash_acl_lookup_value_t *)&result.value;
+  u64 *pmatch = (u64 *)match;
+  u64 *pmask;
+  u64 *pkey;
+  int mask_type_index;
+  u32 curr_match_index = ~0;
+
+  u32 sw_if_index = match->pkt.sw_if_index;
+  u8 is_input = match->pkt.is_input;
+  applied_hash_ace_entry_t **applied_hash_aces = is_input ? &am->input_hash_entry_vec_by_sw_if_index[sw_if_index] :
+                                                    &am->output_hash_entry_vec_by_sw_if_index[sw_if_index];
+  applied_hash_acl_info_t **applied_hash_acls = is_input ? &am->input_applied_hash_acl_info_by_sw_if_index :
+                                                    &am->output_applied_hash_acl_info_by_sw_if_index;
+
+  DBG("TRYING TO MATCH: %016llx %016llx %016llx %016llx %016llx %016llx",
+	       pmatch[0], pmatch[1], pmatch[2], pmatch[3], pmatch[4], pmatch[5]);
+
+  for(mask_type_index=0; mask_type_index < pool_len(am->ace_mask_type_pool); mask_type_index++) {
+    if (!clib_bitmap_get((*applied_hash_acls)[sw_if_index].mask_type_index_bitmap, mask_type_index)) {
+      /* This bit is not set. Avoid trying to match */
+      continue;
+    }
+    ace_mask_type_entry_t *mte = &am->ace_mask_type_pool[mask_type_index];
+    pmatch = (u64 *)match;
+    pmask = (u64 *)&mte->mask;
+    pkey = (u64 *)kv.key;
+    /*
+    * unrolling the below loop results in a noticeable performance increase.
+    int i;
+    for(i=0; i<6; i++) {
+      kv.key[i] = pmatch[i] & pmask[i];
+    }
+    */
+
+    *pkey++ = *pmatch++ & *pmask++;
+    *pkey++ = *pmatch++ & *pmask++;
+    *pkey++ = *pmatch++ & *pmask++;
+    *pkey++ = *pmatch++ & *pmask++;
+    *pkey++ = *pmatch++ & *pmask++;
+    *pkey++ = *pmatch++ & *pmask++;
+
+    kv_key->pkt.mask_type_index_lsb = mask_type_index;
+    DBG("        KEY %3d: %016llx %016llx %016llx %016llx %016llx %016llx", mask_type_index,
+		kv.key[0], kv.key[1], kv.key[2], kv.key[3], kv.key[4], kv.key[5]);
+    int res = BV (clib_bihash_search) (&am->acl_lookup_hash, &kv, &result);
+    if (res == 0) {
+      DBG("ACL-MATCH! result_val: %016llx", result_val->as_u64);
+      if (result_val->applied_entry_index < curr_match_index) {
+	if (PREDICT_FALSE(result_val->need_portrange_check)) {
+          /*
+           * This is going to be slow, since we can have multiple superset
+           * entries for narrow-ish portranges, e.g.:
+           * 0..42 100..400, 230..60000,
+           * so we need to walk linearly and check if they match.
+           */
+
+          u32 curr_index = result_val->applied_entry_index;
+          while ((curr_index != ~0) && !match_portranges(am, match, curr_index)) {
+            /* while no match and there are more entries, walk... */
+            applied_hash_ace_entry_t *pae = &((*applied_hash_aces)[curr_index]);
+            DBG("entry %d did not portmatch, advancing to %d", curr_index, pae->next_applied_entry_index);
+            curr_index = pae->next_applied_entry_index;
+          }
+          if (curr_index < curr_match_index) {
+            DBG("The index %d is the new candidate in portrange matches.", curr_index);
+            curr_match_index = result_val->applied_entry_index;
+	    if (!result_val->shadowed) {
+              /* new result is known to not be shadowed, so no point to look up further */
+              break;
+	    }
+          } else {
+            DBG("Curr portmatch index %d is too big vs. current matched one %d", curr_index, curr_match_index);
+          }
+        } else {
+          /* The usual path is here. Found an entry in front of the current candiate - so it's a new one */
+          DBG("This match is the new candidate");
+          curr_match_index = result_val->applied_entry_index;
+	  if (!result_val->shadowed) {
+          /* new result is known to not be shadowed, so no point to look up further */
+            break;
+	  }
+        }
+      }
+    }
+  }
+  DBG("MATCH-RESULT: %d", curr_match_index);
+  return curr_match_index;
+}
+
+static void
+hashtable_add_del(acl_main_t *am, clib_bihash_kv_48_8_t *kv, int is_add)
+{
+    DBG("HASH ADD/DEL: %016llx %016llx %016llx %016llx %016llx %016llx add %d",
+                        kv->key[0], kv->key[1], kv->key[2],
+                        kv->key[3], kv->key[4], kv->key[5], is_add);
+    BV (clib_bihash_add_del) (&am->acl_lookup_hash, kv, is_add);
+}
+
+static void
+fill_applied_hash_ace_kv(acl_main_t *am,
+                            applied_hash_ace_entry_t **applied_hash_aces,
+                            u32 sw_if_index, u8 is_input,
+                            u32 new_index, clib_bihash_kv_48_8_t *kv)
+{
+  fa_5tuple_t *kv_key = (fa_5tuple_t *)kv->key;
+  hash_acl_lookup_value_t *kv_val = (hash_acl_lookup_value_t *)&kv->value;
+  applied_hash_ace_entry_t *pae = &((*applied_hash_aces)[new_index]);
+  hash_acl_info_t *ha = &am->hash_acl_infos[pae->acl_index];
+
+  memcpy(kv_key, &ha->rules[pae->hash_ace_info_index].match, sizeof(*kv_key));
+  /* initialize the sw_if_index and direction */
+  kv_key->pkt.sw_if_index = sw_if_index;
+  kv_key->pkt.is_input = is_input;
+  kv_val->as_u64 = 0;
+  kv_val->applied_entry_index = new_index;
+  kv_val->need_portrange_check = ha->rules[pae->hash_ace_info_index].src_portrange_not_powerof2 ||
+				   ha->rules[pae->hash_ace_info_index].dst_portrange_not_powerof2;
+  /* by default assume all values are shadowed -> check all mask types */
+  kv_val->shadowed = 1;
+}
+
+static void
+add_del_hashtable_entry(acl_main_t *am,
+                            u32 sw_if_index, u8 is_input,
+                            applied_hash_ace_entry_t **applied_hash_aces,
+			    u32 index, int is_add)
+{
+  clib_bihash_kv_48_8_t kv;
+
+  fill_applied_hash_ace_kv(am, applied_hash_aces, sw_if_index, is_input, index, &kv);
+  hashtable_add_del(am, &kv, is_add);
+}
+
+
+
+static void
+activate_applied_ace_hash_entry(acl_main_t *am,
+                            u32 sw_if_index, u8 is_input,
+                            applied_hash_ace_entry_t **applied_hash_aces,
+                            u32 new_index)
+{
+  clib_bihash_kv_48_8_t kv;
+  applied_hash_ace_entry_t *pae = &((*applied_hash_aces)[new_index]);
+
+  fill_applied_hash_ace_kv(am, applied_hash_aces, sw_if_index, is_input, new_index, &kv);
+
+  DBG("APPLY ADD KY: %016llx %016llx %016llx %016llx %016llx %016llx",
+			kv.key[0], kv.key[1], kv.key[2],
+			kv.key[3], kv.key[4], kv.key[5]);
+
+  clib_bihash_kv_48_8_t result;
+  hash_acl_lookup_value_t *result_val = (hash_acl_lookup_value_t *)&result.value;
+  int res = BV (clib_bihash_search) (&am->acl_lookup_hash, &kv, &result);
+  if (res == 0) {
+    /* There already exists an entry or more. Append at the end. */
+    u32 existing_index = result_val->applied_entry_index;
+    DBG("A key already exists, with applied entry index: %d", existing_index);
+    ASSERT(existing_index != ~0);
+    applied_hash_ace_entry_t *existing_pae = &((*applied_hash_aces)[existing_index]);
+    /* walk the list to the last element */
+    while (existing_pae->next_applied_entry_index != ~0) {
+      if (existing_index == existing_pae->next_applied_entry_index) {
+        DBG("existing and next index of entry %d are the same, abort", existing_index);
+        ASSERT(existing_index != existing_pae->next_applied_entry_index);
+      }
+      existing_index = existing_pae->next_applied_entry_index;
+      existing_pae = &((*applied_hash_aces)[existing_index]);
+      DBG("...advance to chained entry index: %d", existing_index);
+    }
+    /* link ourseves in */
+    existing_pae->next_applied_entry_index = new_index;
+    pae->prev_applied_entry_index = existing_index;
+  } else {
+    /* It's the very first entry */
+    hashtable_add_del(am, &kv, 1);
+  }
+}
+
+static void
+applied_hash_entries_analyze(acl_main_t *am, applied_hash_ace_entry_t **applied_hash_aces)
+{
+  /*
+   * Go over the rules and check which ones are shadowed and which aren't.
+   * Naive approach: try to match the match value from every ACE as if it
+   * was a live packet, and see if the resulting match happens earlier in the list.
+   * if it does not match or it is later in the ACL - then the entry is not shadowed.
+   *
+   * This approach fails, an example:
+   *   deny tcp 2001:db8::/32 2001:db8::/32
+   *   permit ip 2001:db8::1/128 2001:db8::2/128
+   */
+}
+
+void
+hash_acl_apply(acl_main_t *am, u32 sw_if_index, u8 is_input, int acl_index)
+{
+  int i;
+
+  DBG("HASH ACL apply: sw_if_index %d is_input %d acl %d", sw_if_index, is_input, acl_index);
+  u32 *acl_vec = is_input ? am->input_acl_vec_by_sw_if_index[sw_if_index] :
+			    am->output_acl_vec_by_sw_if_index[sw_if_index];
+  if (is_input) {
+    vec_validate(am->input_hash_entry_vec_by_sw_if_index, sw_if_index);
+  } else {
+    vec_validate(am->output_hash_entry_vec_by_sw_if_index, sw_if_index);
+  }
+  vec_validate(am->hash_acl_infos, acl_index);
+  applied_hash_ace_entry_t **applied_hash_aces = is_input ? &am->input_hash_entry_vec_by_sw_if_index[sw_if_index] :
+                                                    &am->output_hash_entry_vec_by_sw_if_index[sw_if_index];
+  u32 order_index = vec_search(acl_vec, acl_index);
+  hash_acl_info_t *ha = &am->hash_acl_infos[acl_index];
+  ASSERT(order_index != ~0);
+
+  if (!am->acl_lookup_hash_initialized) {
+    BV (clib_bihash_init) (&am->acl_lookup_hash, "ACL plugin rule lookup bihash",
+                           65536, 2 << 25);
+    am->acl_lookup_hash_initialized = 1;
+  }
+  int base_offset = vec_len(*applied_hash_aces);
+
+  /* Update the bitmap of the mask types with which the lookup
+     needs to happen for the ACLs applied to this sw_if_index */
+  applied_hash_acl_info_t **applied_hash_acls = is_input ? &am->input_applied_hash_acl_info_by_sw_if_index :
+                                                    &am->output_applied_hash_acl_info_by_sw_if_index;
+  vec_validate((*applied_hash_acls), sw_if_index);
+  applied_hash_acl_info_t *pal = &(*applied_hash_acls)[sw_if_index];
+  pal->mask_type_index_bitmap = clib_bitmap_or(pal->mask_type_index_bitmap,
+                                     ha->mask_type_index_bitmap);
+  /*
+   * if the applied ACL is empty, the current code will cause a
+   * different behavior compared to current linear search: an empty ACL will
+   * simply fallthrough to the next ACL, or the default deny in the end.
+   *
+   * This is not a problem, because after vpp-dev discussion,
+   * the consensus was it should not be possible to apply the non-existent
+   * ACL, so the change adding this code also takes care of that.
+   */
+
+  /* expand the applied aces vector by the necessary amount */
+  vec_resize((*applied_hash_aces), vec_len(ha->rules));
+
+  /* add the rules from the ACL to the hash table for lookup and append to the vector*/
+  for(i=0; i < vec_len(ha->rules); i++) {
+    u32 new_index = base_offset + i;
+    applied_hash_ace_entry_t *pae = &((*applied_hash_aces)[new_index]);
+    pae->acl_index = acl_index;
+    pae->ace_index = ha->rules[i].ace_index;
+    pae->action = ha->rules[i].action;
+    pae->hash_ace_info_index = i;
+    /* we might link it in later */
+    pae->next_applied_entry_index = ~0;
+    pae->prev_applied_entry_index = ~0;
+    activate_applied_ace_hash_entry(am, sw_if_index, is_input, applied_hash_aces, new_index);
+  }
+  applied_hash_entries_analyze(am, applied_hash_aces);
+}
+
+static void
+move_applied_ace_hash_entry(acl_main_t *am,
+                            u32 sw_if_index, u8 is_input,
+                            applied_hash_ace_entry_t **applied_hash_aces,
+                            u32 old_index, u32 new_index)
+{
+
+  /* move the entry */
+  (*applied_hash_aces)[new_index] = (*applied_hash_aces)[old_index];
+
+  /* update the linkage and hash table if necessary */
+  applied_hash_ace_entry_t *pae = &((*applied_hash_aces)[old_index]);
+
+  if (pae->prev_applied_entry_index != ~0) {
+    applied_hash_ace_entry_t *prev_pae = &((*applied_hash_aces)[pae->prev_applied_entry_index]);
+    ASSERT(prev_pae->next_applied_entry_index == old_index);
+    prev_pae->next_applied_entry_index = new_index;
+  } else {
+    /* first entry - so the hash points to it, update */
+    add_del_hashtable_entry(am, sw_if_index, is_input,
+                            applied_hash_aces, new_index, 1);
+  }
+  if (pae->next_applied_entry_index != ~0) {
+    applied_hash_ace_entry_t *next_pae = &((*applied_hash_aces)[pae->next_applied_entry_index]);
+    ASSERT(next_pae->prev_applied_entry_index == old_index);
+    next_pae->prev_applied_entry_index = new_index;
+  }
+  /* invalidate the old entry */
+  pae->prev_applied_entry_index = ~0;
+  pae->next_applied_entry_index = ~0;
+}
+
+static void
+deactivate_applied_ace_hash_entry(acl_main_t *am,
+                            u32 sw_if_index, u8 is_input,
+                            applied_hash_ace_entry_t **applied_hash_aces,
+                            u32 old_index)
+{
+  applied_hash_ace_entry_t *pae = &((*applied_hash_aces)[old_index]);
+
+  if (pae->next_applied_entry_index != ~0) {
+    applied_hash_ace_entry_t *next_pae = &((*applied_hash_aces)[pae->next_applied_entry_index]);
+    ASSERT(next_pae->prev_applied_entry_index == old_index);
+    next_pae->prev_applied_entry_index = pae->prev_applied_entry_index;
+  }
+
+  if (pae->prev_applied_entry_index != ~0) {
+    applied_hash_ace_entry_t *prev_pae = &((*applied_hash_aces)[pae->prev_applied_entry_index]);
+    ASSERT(prev_pae->next_applied_entry_index == old_index);
+    prev_pae->next_applied_entry_index = pae->next_applied_entry_index;
+  } else {
+    /* It was the first entry. We need either to reset the hash entry or delete it */
+    if (pae->next_applied_entry_index != ~0) {
+      add_del_hashtable_entry(am, sw_if_index, is_input,
+                              applied_hash_aces, pae->next_applied_entry_index, 1);
+    } else {
+      /* no next entry, so just delete the entry in the hash table */
+      add_del_hashtable_entry(am, sw_if_index, is_input,
+                              applied_hash_aces, old_index, 0);
+    }
+  }
+}
+
+
+static void
+hash_acl_build_applied_lookup_bitmap(acl_main_t *am, u32 sw_if_index, u8 is_input)
+{
+  int i;
+  uword *new_lookup_bitmap = 0;
+  u32 **applied_acls = is_input ? &am->input_acl_vec_by_sw_if_index[sw_if_index] :
+                                  &am->output_acl_vec_by_sw_if_index[sw_if_index];
+  applied_hash_acl_info_t **applied_hash_acls = is_input ? &am->input_applied_hash_acl_info_by_sw_if_index :
+                                                    &am->output_applied_hash_acl_info_by_sw_if_index;
+  applied_hash_acl_info_t *pal = &(*applied_hash_acls)[sw_if_index];
+  for(i=0; i < vec_len(*applied_acls); i++) {
+    u32 a_acl_index = (*applied_acls)[i];
+    hash_acl_info_t *ha = &am->hash_acl_infos[a_acl_index];
+    new_lookup_bitmap = clib_bitmap_or(new_lookup_bitmap,
+                                       ha->mask_type_index_bitmap);
+  }
+  uword *old_lookup_bitmap = pal->mask_type_index_bitmap;
+  pal->mask_type_index_bitmap = new_lookup_bitmap;
+  clib_bitmap_free(old_lookup_bitmap);
+}
+
+void
+hash_acl_unapply(acl_main_t *am, u32 sw_if_index, u8 is_input, int acl_index)
+{
+  int i;
+
+  DBG("HASH ACL unapply: sw_if_index %d is_input %d acl %d", sw_if_index, is_input, acl_index);
+  hash_acl_info_t *ha = &am->hash_acl_infos[acl_index];
+  applied_hash_ace_entry_t **applied_hash_aces = is_input ? &am->input_hash_entry_vec_by_sw_if_index[sw_if_index] :
+                                                    &am->output_hash_entry_vec_by_sw_if_index[sw_if_index];
+
+  for(i=0; i < vec_len((*applied_hash_aces)); i++) {
+    if ((*applied_hash_aces)[i].acl_index == acl_index) {
+      DBG("Found applied ACL#%d at applied index %d", acl_index, i);
+      break;
+    }
+  }
+  if (vec_len((*applied_hash_aces)) <= i) {
+    DBG("Did not find applied ACL#%d at sw_if_index %d", acl_index, sw_if_index);
+    /* we went all the way without finding any entries. Probably a list was empty. */
+    return;
+  }
+  int base_offset = i;
+  int tail_offset = base_offset + vec_len(ha->rules);
+  int tail_len = vec_len((*applied_hash_aces)) - tail_offset;
+  DBG("base_offset: %d, tail_offset: %d, tail_len: %d", base_offset, tail_offset, tail_len);
+
+  for(i=0; i < vec_len(ha->rules); i ++) {
+    DBG("UNAPPLY DEACTIVATE: sw_if_index %d is_input %d, applied index %d", sw_if_index, is_input, base_offset + i);
+    deactivate_applied_ace_hash_entry(am, sw_if_index, is_input,
+                                      applied_hash_aces, base_offset + i);
+  }
+  for(i=0; i < tail_len; i ++) {
+    /* move the entry at tail offset to base offset */
+    /* that is, from (tail_offset+i) -> (base_offset+i) */
+    DBG("UNAPPLY MOVE: sw_if_index %d is_input %d, applied index %d ->", sw_if_index, is_input, tail_offset+i, base_offset + i);
+    move_applied_ace_hash_entry(am, sw_if_index, is_input, applied_hash_aces, tail_offset + i, base_offset + i);
+  }
+  /* trim the end of the vector */
+  _vec_len((*applied_hash_aces)) -= vec_len(ha->rules);
+
+  applied_hash_entries_analyze(am, applied_hash_aces);
+
+  /* After deletion we might not need some of the mask-types anymore... */
+  hash_acl_build_applied_lookup_bitmap(am, sw_if_index, is_input);
+}
+
+/*
+ * Create the applied ACEs and update the hash table,
+ * taking into account that the ACL may not be the last
+ * in the vector of applied ACLs.
+ *
+ * For now, walk from the end of the vector and unapply the ACLs,
+ * then apply the one in question and reapply the rest.
+ */
+
+void
+hash_acl_reapply(acl_main_t *am, u32 sw_if_index, u8 is_input, int acl_index)
+{
+  u32 **applied_acls = is_input ? &am->input_acl_vec_by_sw_if_index[sw_if_index] :
+				  &am->output_acl_vec_by_sw_if_index[sw_if_index];
+  int i;
+  int start_index = vec_search((*applied_acls), acl_index);
+  /*
+   * This function is called after we find out the sw_if_index where ACL is applied.
+   * If the by-sw_if_index vector does not have the ACL#, then it's a bug.
+   */
+  ASSERT(start_index < vec_len(*applied_acls));
+
+  /* unapply all the ACLs till the current one */
+  for(i = vec_len(*applied_acls) - 1; i >= start_index; i--) {
+    hash_acl_unapply(am, sw_if_index, is_input, (*applied_acls)[i]);
+  }
+  for(i = start_index; i < vec_len(*applied_acls); i++) {
+    hash_acl_apply(am, sw_if_index, is_input, (*applied_acls)[i]);
+  }
+}
+
+static void
+make_address_mask(ip46_address_t *addr, u8 is_ipv6, u8 prefix_len)
+{
+  if (is_ipv6) {
+    ip6_address_mask_from_width(&addr->ip6, prefix_len);
+  } else {
+    /* FIXME: this may not be correct way */
+    ip6_address_mask_from_width(&addr->ip6, prefix_len + 3*32);
+    ip46_address_mask_ip4(addr);
+  }
+}
+
+static u8
+make_port_mask(u16 *portmask, u16 port_first, u16 port_last)
+{
+  if (port_first == port_last) {
+    *portmask = 0xffff;
+    /* single port is representable by masked value */
+    return 0;
+  }
+  if ((port_first == 0) && (port_last == 65535)) {
+    *portmask = 0;
+    /* wildcard port is representable by a masked value */
+    return 0;
+  }
+
+  /*
+   * For now match all the ports, later
+   * here might be a better optimization which would
+   * pick out bitmaskable portranges.
+   *
+   * However, adding a new mask type potentially
+   * adds a per-packet extra lookup, so the benefit is not clear.
+   */
+  *portmask = 0;
+  /* This port range can't be represented via bitmask exactly. */
+  return 1;
+}
+
+static void
+make_mask_and_match_from_rule(fa_5tuple_t *mask, acl_rule_t *r, hash_ace_info_t *hi, int match_nonfirst_fragment)
+{
+  memset(mask, 0, sizeof(*mask));
+  memset(&hi->match, 0, sizeof(hi->match));
+  hi->action = r->is_permit;
+
+  /* we will need to be matching based on sw_if_index, direction, and mask_type_index when applied */
+  mask->pkt.sw_if_index = ~0;
+  mask->pkt.is_input = 1;
+  /* we will assign the match of mask_type_index later when we find it*/
+  mask->pkt.mask_type_index_lsb = ~0;
+
+  mask->pkt.is_ip6 = 1;
+  hi->match.pkt.is_ip6 = r->is_ipv6;
+
+  make_address_mask(&mask->addr[0], r->is_ipv6, r->src_prefixlen);
+  hi->match.addr[0] = r->src;
+  make_address_mask(&mask->addr[1], r->is_ipv6, r->dst_prefixlen);
+  hi->match.addr[1] = r->dst;
+
+  if (r->proto != 0) {
+    mask->l4.proto = ~0; /* L4 proto needs to be matched */
+    hi->match.l4.proto = r->proto;
+    if (match_nonfirst_fragment) {
+      /* match the non-first fragments only */
+      mask->pkt.is_nonfirst_fragment = 1;
+      hi->match.pkt.is_nonfirst_fragment = 1;
+    } else {
+      /* Calculate the src/dst port masks and make the src/dst port matches accordingly */
+      hi->src_portrange_not_powerof2 = make_port_mask(&mask->l4.port[0], r->src_port_or_type_first, r->src_port_or_type_last);
+      hi->match.l4.port[0] = r->src_port_or_type_first & mask->l4.port[0];
+      hi->dst_portrange_not_powerof2 = make_port_mask(&mask->l4.port[1], r->dst_port_or_code_first, r->dst_port_or_code_last);
+      hi->match.l4.port[1] = r->dst_port_or_code_first & mask->l4.port[1];
+      /* L4 info must be valid in order to match */
+      mask->pkt.l4_valid = 1;
+      hi->match.pkt.l4_valid = 1;
+      /* And we must set the mask to check that it is an initial fragment */
+      mask->pkt.is_nonfirst_fragment = 1;
+      hi->match.pkt.is_nonfirst_fragment = 0;
+      if ((r->proto == IPPROTO_TCP) && (r->tcp_flags_mask != 0)) {
+	/* if we want to match on TCP flags, they must be masked off as well */
+	mask->pkt.tcp_flags = r->tcp_flags_mask;
+	hi->match.pkt.tcp_flags = r->tcp_flags_value;
+	/* and the flags need to be present within the packet being matched */
+	mask->pkt.tcp_flags_valid = 1;
+	hi->match.pkt.tcp_flags_valid = 1;
+      }
+    }
+  }
+  /* Sanitize the mask and the match */
+  u64 *pmask = (u64 *)mask;
+  u64 *pmatch = (u64 *)&hi->match;
+  int j;
+  for(j=0; j<6; j++) {
+    pmatch[j] = pmatch[j] & pmask[j];
+  }
+}
+
+static u32
+find_mask_type_index(acl_main_t *am, fa_5tuple_t *mask)
+{
+  ace_mask_type_entry_t *mte;
+  /* *INDENT-OFF* */
+  pool_foreach(mte, am->ace_mask_type_pool,
+  ({
+    if(memcmp(&mte->mask, mask, sizeof(*mask)) == 0)
+      return (mte - am->ace_mask_type_pool);
+  }));
+  /* *INDENT-ON* */
+  return ~0;
+}
+
+static u32
+assign_mask_type_index(acl_main_t *am, fa_5tuple_t *mask)
+{
+  u32 mask_type_index = find_mask_type_index(am, mask);
+  ace_mask_type_entry_t *mte;
+  if(~0 == mask_type_index) {
+    pool_get_aligned (am->ace_mask_type_pool, mte, CLIB_CACHE_LINE_BYTES);
+    mask_type_index = mte - am->ace_mask_type_pool;
+    clib_memcpy(&mte->mask, mask, sizeof(mte->mask));
+    mte->refcount = 0;
+    /*
+     * We can use only 16 bits, since in the match there is only u16 field.
+     * Realistically, once you go to 64K of mask types, it is a huge
+     * problem anyway, so we might as well stop half way.
+     */
+    ASSERT(mask_type_index < 32768);
+  }
+  mte = am->ace_mask_type_pool + mask_type_index;
+  mte->refcount++;
+  return mask_type_index;
+}
+
+static void
+release_mask_type_index(acl_main_t *am, u32 mask_type_index)
+{
+  ace_mask_type_entry_t *mte = &am->ace_mask_type_pool[mask_type_index];
+  mte->refcount--;
+  if (mte->refcount == 0) {
+    /* we are not using this entry anymore */
+    pool_put(am->ace_mask_type_pool, mte);
+  }
+}
+
+void hash_acl_add(acl_main_t *am, int acl_index)
+{
+  DBG("HASH ACL add : %d", acl_index);
+  int i;
+  acl_list_t *a = &am->acls[acl_index];
+  vec_validate(am->hash_acl_infos, acl_index);
+  hash_acl_info_t *ha = &am->hash_acl_infos[acl_index];
+  memset(ha, 0, sizeof(*ha));
+
+  /* walk the newly added ACL entries and ensure that for each of them there
+     is a mask type, increment a reference count for that mask type */
+  for(i=0; i < a->count; i++) {
+    hash_ace_info_t ace_info;
+    fa_5tuple_t mask;
+    memset(&ace_info, 0, sizeof(ace_info));
+    ace_info.acl_index = acl_index;
+    ace_info.ace_index = i;
+
+    make_mask_and_match_from_rule(&mask, &a->rules[i], &ace_info, 0);
+    ace_info.mask_type_index = assign_mask_type_index(am, &mask);
+    /* assign the mask type index for matching itself */
+    ace_info.match.pkt.mask_type_index_lsb = ace_info.mask_type_index;
+    DBG("ACE: %d mask_type_index: %d", i, ace_info.mask_type_index);
+    /* Ensure a given index is set in the mask type index bitmap for this ACL */
+    ha->mask_type_index_bitmap = clib_bitmap_set(ha->mask_type_index_bitmap, ace_info.mask_type_index, 1);
+    vec_add1(ha->rules, ace_info);
+    if (am->l4_match_nonfirst_fragment) {
+      /* add the second rule which matches the noninitial fragments with the respective mask */
+      make_mask_and_match_from_rule(&mask, &a->rules[i], &ace_info, 1);
+      ace_info.mask_type_index = assign_mask_type_index(am, &mask);
+      ace_info.match.pkt.mask_type_index_lsb = ace_info.mask_type_index;
+      DBG("ACE: %d (non-initial frags) mask_type_index: %d", i, ace_info.mask_type_index);
+      /* Ensure a given index is set in the mask type index bitmap for this ACL */
+      ha->mask_type_index_bitmap = clib_bitmap_set(ha->mask_type_index_bitmap, ace_info.mask_type_index, 1);
+      vec_add1(ha->rules, ace_info);
+    }
+  }
+  /*
+   * if an ACL is applied somewhere, fill the corresponding lookup data structures.
+   * We need to take care if the ACL is not the last one in the vector of ACLs applied to the interface.
+   */
+  if (acl_index < vec_len(am->input_sw_if_index_vec_by_acl)) {
+    u32 *sw_if_index;
+    vec_foreach(sw_if_index, am->input_sw_if_index_vec_by_acl[acl_index]) {
+      hash_acl_reapply(am, *sw_if_index, 1, acl_index);
+    }
+  }
+  if (acl_index < vec_len(am->output_sw_if_index_vec_by_acl)) {
+    u32 *sw_if_index;
+    vec_foreach(sw_if_index, am->output_sw_if_index_vec_by_acl[acl_index]) {
+      hash_acl_reapply(am, *sw_if_index, 0, acl_index);
+    }
+  }
+}
+
+void hash_acl_delete(acl_main_t *am, int acl_index)
+{
+  DBG("HASH ACL delete : %d", acl_index);
+  /*
+   * If the ACL is applied somewhere, remove the references of it (call hash_acl_unapply)
+   * this is a different behavior from the linear lookup where an empty ACL is "deny all",
+   *
+   * However, following vpp-dev discussion the ACL that is referenced elsewhere
+   * should not be possible to delete, and the change adding this also adds
+   * the safeguards to that respect, so this is not a problem.
+   */
+  if (acl_index < vec_len(am->input_sw_if_index_vec_by_acl)) {
+    u32 *sw_if_index;
+    vec_foreach(sw_if_index, am->input_sw_if_index_vec_by_acl[acl_index]) {
+      hash_acl_unapply(am, *sw_if_index, 1, acl_index);
+    }
+  }
+  if (acl_index < vec_len(am->output_sw_if_index_vec_by_acl)) {
+    u32 *sw_if_index;
+    vec_foreach(sw_if_index, am->output_sw_if_index_vec_by_acl[acl_index]) {
+      hash_acl_unapply(am, *sw_if_index, 0, acl_index);
+    }
+  }
+
+  /* walk the mask types for the ACL about-to-be-deleted, and decrease
+   * the reference count, possibly freeing up some of them */
+  int i;
+  hash_acl_info_t *ha = &am->hash_acl_infos[acl_index];
+  for(i=0; i < vec_len(ha->rules); i++) {
+    release_mask_type_index(am, ha->rules[i].mask_type_index);
+  }
+  clib_bitmap_free(ha->mask_type_index_bitmap);
+  vec_free(ha->rules);
+}
+
+u8
+hash_multi_acl_match_5tuple (u32 sw_if_index, fa_5tuple_t * pkt_5tuple, int is_l2,
+                       int is_ip6, int is_input, u32 * acl_match_p,
+                       u32 * rule_match_p, u32 * trace_bitmap)
+{
+  acl_main_t *am = &acl_main;
+  applied_hash_ace_entry_t **applied_hash_aces = is_input ? &am->input_hash_entry_vec_by_sw_if_index[sw_if_index] :
+                                                    &am->output_hash_entry_vec_by_sw_if_index[sw_if_index];
+  u32 match_index = multi_acl_match_get_applied_ace_index(am, pkt_5tuple);
+  if (match_index < vec_len((*applied_hash_aces))) {
+    applied_hash_ace_entry_t *pae = &((*applied_hash_aces)[match_index]);
+    *acl_match_p = pae->acl_index;
+    *rule_match_p = pae->ace_index;
+    return pae->action;
+  }
+  return 0;
+}
+
+
+void
+show_hash_acl_hash (vlib_main_t * vm, acl_main_t *am, u32 verbose)
+{
+  vlib_cli_output(vm, "\nACL lookup hash table:\n%U\n",
+                  BV (format_bihash), &am->acl_lookup_hash, verbose);
+}