acl-plugin: implement ACL lookup contexts for "ACL as a service" use by other plugins

This code implements the functionality required for other plugins wishing
to perform ACL lookups in the contexts of their choice, rather than only
in the context of the interface in/out.

The lookups are the stateless ACLs - there is no concept of "direction"
within the context, hence no concept of "connection" either.

The plugins need to include the

The file acl_lookup_context.md has more info.

Change-Id: I91ba97428cc92b24d1517e808dc2fd8e56ea2f8d
Signed-off-by: Andrew Yourtchenko <ayourtch@gmail.com>

1 files changed, 304 insertions, 0 deletions

diff --git a/src/plugins/acl/lookup_context.c b/src/plugins/acl/lookup_context.c
new file mode 100644
index 00000000000..a4c9647776a
--- /dev/null
+++ b/src/plugins/acl/lookup_context.c
@@ -0,0 +1,304 @@
+/*
+ * 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 <plugins/acl/acl.h>
+#include <plugins/acl/fa_node.h>
+#include <plugins/acl/public_inlines.h>
+#include <vlib/unix/plugin.h>
+#include "hash_lookup.h"
+#include "elog_acl_trace.h"
+
+/* check if a given ACL exists */
+u8 acl_plugin_acl_exists (u32 acl_index);
+
+static u32 get_acl_user_id(acl_main_t *am, char *user_module_name, char *val1_label, char *val2_label)
+{
+    acl_lookup_context_user_t *auser;
+
+    pool_foreach (auser, am->acl_users,
+    ({
+      if (0 == strcmp(auser->user_module_name, user_module_name)) {
+        return (auser - am->acl_users);
+      }
+    }));
+
+    pool_get(am->acl_users, auser);
+    auser->user_module_name = user_module_name;
+    auser->val1_label = val1_label;
+    auser->val2_label = val2_label;
+    return (auser - am->acl_users);
+}
+
+static int acl_user_id_valid(acl_main_t *am, u32 acl_user_id)
+{
+
+  if (pool_is_free_index (am->acl_users, acl_user_id))
+    return 0;
+
+  return 1;
+}
+
+static int acl_lc_index_valid(acl_main_t *am, u32 lc_index)
+{
+
+  if (pool_is_free_index (am->acl_lookup_contexts, lc_index))
+    return 0;
+
+  return 1;
+}
+
+/*
+ * If you are using ACL plugin, get this unique ID first,
+ * so you can identify yourself when creating the lookup contexts.
+ */
+
+u32 acl_plugin_register_user_module (char *user_module_name, char *val1_label, char *val2_label)
+{
+  acl_main_t *am = &acl_main;
+  u32 user_id = get_acl_user_id(am, user_module_name, val1_label, val2_label);
+  return user_id;
+}
+
+/*
+ * Allocate a new lookup context index.
+ * Supply the id assigned to your module during registration,
+ * and two values of your choice identifying instances
+ * of use within your module. They are useful for debugging.
+ * If >= 0 - context id. If < 0 - error code.
+ */
+
+int acl_plugin_get_lookup_context_index (u32 acl_user_id, u32 val1, u32 val2)
+{
+  acl_main_t *am = &acl_main;
+  acl_lookup_context_t *acontext;
+
+  if (!acl_user_id_valid(am, acl_user_id))
+    return VNET_API_ERROR_INVALID_REGISTRATION;
+
+  pool_get(am->acl_lookup_contexts, acontext);
+  acontext->acl_indices = 0;
+  acontext->context_user_id = acl_user_id;
+  acontext->user_val1 = val1;
+  acontext->user_val2 = val2;
+
+  u32 new_context_id = acontext - am->acl_lookup_contexts;
+  vec_add1(am->acl_users[acl_user_id].lookup_contexts, new_context_id);
+  return new_context_id;
+}
+
+static void
+lock_acl(acl_main_t *am, u32 acl, u32 lc_index)
+{
+  vec_validate(am->lc_index_vec_by_acl, acl);
+  elog_acl_cond_trace_X2(am, (am->trace_acl), "lock acl %d in lc_index %d", "i4i4", acl, lc_index);
+  vec_add1(am->lc_index_vec_by_acl[acl], lc_index);
+}
+
+static void
+lock_acl_vec(u32 lc_index, u32 *acls)
+{
+  int i;
+  acl_main_t *am = &acl_main;
+  for(i=0; i<vec_len(acls); i++) {
+    lock_acl(am, acls[i], lc_index);
+  }
+}
+
+static void
+unlock_acl(acl_main_t *am, u32 acl, u32 lc_index)
+{
+  vec_validate(am->lc_index_vec_by_acl, acl);
+  elog_acl_cond_trace_X2(am, (am->trace_acl), "unlock acl %d in lc_index %d", "i4i4", acl, lc_index);
+  u32 index = vec_search(am->lc_index_vec_by_acl[acl], lc_index);
+  if (index != ~0)
+    vec_del1(am->lc_index_vec_by_acl[acl], index);
+  else
+    clib_warning("BUG: can not unlock acl %d lc_index %d", acl, lc_index);
+}
+
+static void
+unlock_acl_vec(u32 lc_index, u32 *acls)
+{
+  int i;
+  acl_main_t *am = &acl_main;
+  for(i=0; i<vec_len(acls); i++)
+  unlock_acl(am, acls[i], lc_index);
+}
+
+
+static void
+apply_acl_vec(u32 lc_index, u32 *acls)
+{
+  int i;
+  acl_main_t *am = &acl_main;
+
+  for(i=0; i<vec_len(acls); i++)
+    hash_acl_apply(am, lc_index, acls[i], i);
+}
+
+
+static void
+unapply_acl_vec(u32 lc_index, u32 *acls)
+{
+  int i;
+  acl_main_t *am = &acl_main;
+  if (vec_len(acls) == 0)
+    return;
+  for(i=vec_len(acls); i > 0; i--)
+    hash_acl_unapply(am, lc_index, acls[i-1]);
+}
+
+/*
+ * Release the lookup context index and destroy
+ * any asssociated data structures.
+ */
+void acl_plugin_put_lookup_context_index (u32 lc_index)
+{
+  acl_main_t *am = &acl_main;
+  elog_acl_cond_trace_X1(am, (am->trace_acl), "LOOKUP-CONTEXT: put-context lc_index %d", "i4", lc_index);
+  if (!acl_lc_index_valid(am, lc_index)) {
+    clib_warning("BUG: lc_index %d is not valid", lc_index);
+    return;
+  }
+  acl_lookup_context_t *acontext = pool_elt_at_index(am->acl_lookup_contexts, lc_index);
+
+  u32 index = vec_search(am->acl_users[acontext->context_user_id].lookup_contexts, lc_index);
+  ASSERT(index != ~0);
+
+  vec_del1(am->acl_users[acontext->context_user_id].lookup_contexts, index);
+  unapply_acl_vec(lc_index, acontext->acl_indices);
+  unlock_acl_vec(lc_index, acontext->acl_indices);
+  vec_free(acontext->acl_indices);
+  pool_put(am->acl_lookup_contexts, acontext);
+}
+
+/*
+ * Prepare the sequential vector of ACL#s to lookup within a given context.
+ * Any existing list will be overwritten. acl_list is a vector.
+ */
+int acl_plugin_set_acl_vec_for_context (u32 lc_index, u32 *acl_list)
+{
+  acl_main_t *am = &acl_main;
+  acl_lookup_context_t *acontext;
+  if (am->trace_acl) {
+    u32 i;
+    elog_acl_cond_trace_X1(am, (1), "LOOKUP-CONTEXT: set-acl-list lc_index %d", "i4", lc_index);
+    for(i=0; i<vec_len(acl_list); i++) {
+      elog_acl_cond_trace_X2(am, (1), "   acl-list[%d]: %d", "i4i4", i, acl_list[i]);
+    }
+  }  
+  if (!acl_lc_index_valid(am, lc_index)) {
+    clib_warning("BUG: lc_index %d is not valid", lc_index);
+    return -1;
+  }
+  acontext = pool_elt_at_index(am->acl_lookup_contexts, lc_index);
+  u32 *old_acl_vector = acontext->acl_indices;
+  acontext->acl_indices = vec_dup(acl_list);
+
+  unapply_acl_vec(lc_index, old_acl_vector);
+  unlock_acl_vec(lc_index, old_acl_vector);
+  lock_acl_vec(lc_index, acontext->acl_indices);
+  apply_acl_vec(lc_index, acontext->acl_indices);
+
+  vec_free(old_acl_vector);
+  return 0;
+}
+
+
+void acl_plugin_lookup_context_notify_acl_change(u32 acl_num)
+{
+  acl_main_t *am = &acl_main;
+  if (acl_plugin_acl_exists(acl_num)) {
+    if (hash_acl_exists(am, acl_num)) {
+        /* this is a modification, clean up the older entries */
+        hash_acl_delete(am, acl_num);
+    }
+    hash_acl_add(am, acl_num);
+  } else {
+    /* this is a deletion notification */
+    hash_acl_delete(am, acl_num);
+  }
+}
+
+
+/* Fill the 5-tuple from the packet */
+
+void acl_plugin_fill_5tuple (u32 lc_index, vlib_buffer_t * b0, int is_ip6, int is_input,
+                                int is_l2_path, fa_5tuple_opaque_t * p5tuple_pkt)
+{
+  acl_plugin_fill_5tuple_inline(lc_index, b0, is_ip6, is_input, is_l2_path, p5tuple_pkt);
+}
+
+int acl_plugin_match_5tuple (u32 lc_index,
+                                           fa_5tuple_opaque_t * pkt_5tuple,
+                                           int is_ip6, u8 * r_action,
+                                           u32 * r_acl_pos_p,
+                                           u32 * r_acl_match_p,
+                                           u32 * r_rule_match_p,
+                                           u32 * trace_bitmap)
+{
+  return acl_plugin_match_5tuple_inline (lc_index, pkt_5tuple, is_ip6, r_action, r_acl_pos_p, r_acl_match_p, r_rule_match_p, trace_bitmap);
+}
+
+
+void
+acl_plugin_show_lookup_user (u32 user_index)
+{
+    acl_main_t *am = &acl_main;
+    vlib_main_t *vm = am->vlib_main;
+    acl_lookup_context_user_t *auser;
+
+    pool_foreach (auser, am->acl_users,
+    ({
+      u32 curr_user_index = (auser - am->acl_users);
+      if (user_index == ~0 || (curr_user_index == user_index)) {
+        vlib_cli_output (vm, "index %d:%s:%s:%s", curr_user_index, auser->user_module_name, auser->val1_label, auser->val2_label);
+      }
+    }));
+}
+
+
+void
+acl_plugin_show_lookup_context (u32 lc_index)
+{
+  acl_main_t *am = &acl_main;
+  vlib_main_t *vm = am->vlib_main;
+  acl_lookup_context_t *acontext;
+  // clib_warning("LOOKUP-CONTEXT: lc_index %d acl_list [ %U ]", lc_index, format_vec32, acl_list, "%d");
+  if (!am->acl_lookup_contexts)
+  {
+    vlib_cli_output(vm, "ACL lookup contexts are not initialized");
+    return;
+  }
+
+  pool_foreach (acontext, am->acl_lookup_contexts,
+  ({
+    u32 curr_lc_index = (acontext - am->acl_lookup_contexts);
+    if ((lc_index == ~0) || (curr_lc_index == lc_index)) {
+      if (acl_user_id_valid(am, acontext->context_user_id)) {
+        acl_lookup_context_user_t *auser = pool_elt_at_index(am->acl_users, acontext->context_user_id);
+        vlib_cli_output (vm, "index %d:%s %s: %d %s: %d, acl_indices: %U",
+                       curr_lc_index, auser->user_module_name, auser->val1_label,
+                       acontext->user_val1, auser->val2_label, acontext->user_val2,
+                       format_vec32, acontext->acl_indices, "%d");
+      } else {
+        vlib_cli_output (vm, "index %d: user_id: %d user_val1: %d user_val2: %d, acl_indices: %U",
+                       curr_lc_index, acontext->context_user_id,
+                       acontext->user_val1, acontext->user_val2,
+                       format_vec32, acontext->acl_indices, "%d");
+      }
+    }
+  }));
+}