Quelle  prestera_acl.c   Sprache: C

// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
/* Copyright (c) 2020-2021 Marvell International Ltd. All rights reserved */

#include <linux/rhashtable.h>

#include "prestera_acl.h"
#include "prestera_flow.h"
#include "prestera_hw.h"
#include "prestera.h"

#define ACL_KEYMASK_SIZE \
 (sizeof(__be32) * __PRESTERA_ACL_RULE_MATCH_TYPE_MAX)

struct prestera_acl {
 struct prestera_switch *sw;
 struct list_head vtcam_list;
 struct list_head rules;
 struct rhashtable ruleset_ht;
 struct rhashtable acl_rule_entry_ht;
 struct idr uid;
};

struct prestera_acl_ruleset_ht_key {
 struct prestera_flow_block *block;
 u32 chain_index;
};

struct prestera_acl_rule_entry {
 struct rhash_head ht_node;
 struct prestera_acl_rule_entry_key key;
 u32 hw_id;
 u32 vtcam_id;
 struct {
  struct {
   u8 valid:1;
  } accept, drop, trap;
  struct {
   u8 valid:1;
   struct prestera_acl_action_police i;
  } police;
  struct {
   struct prestera_acl_action_jump i;
   u8 valid:1;
  } jump;
  struct {
   u32 id;
   struct prestera_counter_block *block;
  } counter;
 };
};

struct prestera_acl_ruleset {
 struct rhash_head ht_node; /* Member of acl HT */
 struct prestera_acl_ruleset_ht_key ht_key;
 struct rhashtable rule_ht;
 struct prestera_acl *acl;
 struct {
  u32 min;
  u32 max;
 } prio;
 unsigned long rule_count;
 refcount_t refcount;
 void *keymask;
 u32 vtcam_id;
 u32 index;
 u16 pcl_id;
 bool offload;
 bool ingress;
};

struct prestera_acl_vtcam {
 struct list_head list;
 __be32 keymask[__PRESTERA_ACL_RULE_MATCH_TYPE_MAX];
 refcount_t refcount;
 u32 id;
 bool is_keymask_set;
 u8 lookup;
 u8 direction;
};

static const struct rhashtable_params prestera_acl_ruleset_ht_params = {
 .key_len = sizeof(struct prestera_acl_ruleset_ht_key),
 .key_offset = offsetof(struct prestera_acl_ruleset, ht_key),
 .head_offset = offsetof(struct prestera_acl_ruleset, ht_node),
 .automatic_shrinking = true,
};

static const struct rhashtable_params prestera_acl_rule_ht_params = {
 .key_len = sizeof(unsigned long),
 .key_offset = offsetof(struct prestera_acl_rule, cookie),
 .head_offset = offsetof(struct prestera_acl_rule, ht_node),
 .automatic_shrinking = true,
};

static const struct rhashtable_params __prestera_acl_rule_entry_ht_params = {
 .key_offset  = offsetof(struct prestera_acl_rule_entry, key),
 .head_offset = offsetof(struct prestera_acl_rule_entry, ht_node),
 .key_len     = sizeof(struct prestera_acl_rule_entry_key),
 .automatic_shrinking = true,
};

int prestera_acl_chain_to_client(u32 chain_index, bool ingress, u32 *client)
{
 static const u32 ingress_client_map[] = {
  PRESTERA_HW_COUNTER_CLIENT_INGRESS_LOOKUP_0,
  PRESTERA_HW_COUNTER_CLIENT_INGRESS_LOOKUP_1,
  PRESTERA_HW_COUNTER_CLIENT_INGRESS_LOOKUP_2
 };

 if (!ingress) {
  /* prestera supports only one chain on egress */
  if (chain_index > 0)
   return -EINVAL;

  *client = PRESTERA_HW_COUNTER_CLIENT_EGRESS_LOOKUP;
  return 0;
 }

 if (chain_index >= ARRAY_SIZE(ingress_client_map))
  return -EINVAL;

 *client = ingress_client_map[chain_index];
 return 0;
}

static bool prestera_acl_chain_is_supported(u32 chain_index, bool ingress)
{
 if (!ingress)
  /* prestera supports only one chain on egress */
  return chain_index == 0;

 return (chain_index & ~PRESTERA_ACL_CHAIN_MASK) == 0;
}

static struct prestera_acl_ruleset *
prestera_acl_ruleset_create(struct prestera_acl *acl,
       struct prestera_flow_block *block,
       u32 chain_index)
{
 struct prestera_acl_ruleset *ruleset;
 u32 uid = 0;
 int err;

 if (!prestera_acl_chain_is_supported(chain_index, block->ingress))
  return ERR_PTR(-EINVAL);

 ruleset = kzalloc(sizeof(*ruleset), GFP_KERNEL);
 if (!ruleset)
  return ERR_PTR(-ENOMEM);

 ruleset->acl = acl;
 ruleset->ingress = block->ingress;
 ruleset->ht_key.block = block;
 ruleset->ht_key.chain_index = chain_index;
 refcount_set(&ruleset->refcount, 1);

 err = rhashtable_init(&ruleset->rule_ht, &prestera_acl_rule_ht_params);
 if (err)
  goto err_rhashtable_init;

 err = idr_alloc_u32(&acl->uid, NULL, &uid, U8_MAX, GFP_KERNEL);
 if (err)
  goto err_ruleset_create;

 /* make pcl-id based on uid */
 ruleset->pcl_id = PRESTERA_ACL_PCL_ID_MAKE((u8)uid, chain_index);
 ruleset->index = uid;

 ruleset->prio.min = UINT_MAX;
 ruleset->prio.max = 0;

 err = rhashtable_insert_fast(&acl->ruleset_ht, &ruleset->ht_node,
         prestera_acl_ruleset_ht_params);
 if (err)
  goto err_ruleset_ht_insert;

 return ruleset;

err_ruleset_ht_insert:
 idr_remove(&acl->uid, uid);
err_ruleset_create:
 rhashtable_destroy(&ruleset->rule_ht);
err_rhashtable_init:
 kfree(ruleset);
 return ERR_PTR(err);
}

int prestera_acl_ruleset_keymask_set(struct prestera_acl_ruleset *ruleset,
         void *keymask)
{
 ruleset->keymask = kmemdup(keymask, ACL_KEYMASK_SIZE, GFP_KERNEL);
 if (!ruleset->keymask)
  return -ENOMEM;

 return 0;
}

int prestera_acl_ruleset_offload(struct prestera_acl_ruleset *ruleset)
{
 struct prestera_acl_iface iface;
 u32 vtcam_id;
 int dir;
 int err;

 dir = ruleset->ingress ?
  PRESTERA_HW_VTCAM_DIR_INGRESS : PRESTERA_HW_VTCAM_DIR_EGRESS;

 if (ruleset->offload)
  return -EEXIST;

 err = prestera_acl_vtcam_id_get(ruleset->acl,
     ruleset->ht_key.chain_index,
     dir,
     ruleset->keymask, &vtcam_id);
 if (err)
  goto err_vtcam_create;

 if (ruleset->ht_key.chain_index) {
  /* for chain > 0, bind iface index to pcl-id to be able
 * to jump from any other ruleset to this one using the index.
 */
  iface.index = ruleset->index;
  iface.type = PRESTERA_ACL_IFACE_TYPE_INDEX;
  err = prestera_hw_vtcam_iface_bind(ruleset->acl->sw, &iface,
         vtcam_id, ruleset->pcl_id);
  if (err)
   goto err_ruleset_bind;
 }

 ruleset->vtcam_id = vtcam_id;
 ruleset->offload = true;
 return 0;

err_ruleset_bind:
 prestera_acl_vtcam_id_put(ruleset->acl, ruleset->vtcam_id);
err_vtcam_create:
 return err;
}

static void prestera_acl_ruleset_destroy(struct prestera_acl_ruleset *ruleset)
{
 struct prestera_acl *acl = ruleset->acl;
 u8 uid = ruleset->pcl_id & PRESTERA_ACL_KEYMASK_PCL_ID_USER;
 int err;

 rhashtable_remove_fast(&acl->ruleset_ht, &ruleset->ht_node,
          prestera_acl_ruleset_ht_params);

 if (ruleset->offload) {
  if (ruleset->ht_key.chain_index) {
   struct prestera_acl_iface iface = {
    .type = PRESTERA_ACL_IFACE_TYPE_INDEX,
    .index = ruleset->index
   };
   err = prestera_hw_vtcam_iface_unbind(acl->sw, &iface,
            ruleset->vtcam_id);
   WARN_ON(err);
  }
  WARN_ON(prestera_acl_vtcam_id_put(acl, ruleset->vtcam_id));
 }

 idr_remove(&acl->uid, uid);
 rhashtable_destroy(&ruleset->rule_ht);
 kfree(ruleset->keymask);
 kfree(ruleset);
}

static struct prestera_acl_ruleset *
__prestera_acl_ruleset_lookup(struct prestera_acl *acl,
         struct prestera_flow_block *block,
         u32 chain_index)
{
 struct prestera_acl_ruleset_ht_key ht_key;

 memset(&ht_key, 0, sizeof(ht_key));
 ht_key.block = block;
 ht_key.chain_index = chain_index;
 return rhashtable_lookup_fast(&acl->ruleset_ht, &ht_key,
          prestera_acl_ruleset_ht_params);
}

struct prestera_acl_ruleset *
prestera_acl_ruleset_lookup(struct prestera_acl *acl,
       struct prestera_flow_block *block,
       u32 chain_index)
{
 struct prestera_acl_ruleset *ruleset;

 ruleset = __prestera_acl_ruleset_lookup(acl, block, chain_index);
 if (!ruleset)
  return ERR_PTR(-ENOENT);

 refcount_inc(&ruleset->refcount);
 return ruleset;
}

struct prestera_acl_ruleset *
prestera_acl_ruleset_get(struct prestera_acl *acl,
    struct prestera_flow_block *block,
    u32 chain_index)
{
 struct prestera_acl_ruleset *ruleset;

 ruleset = __prestera_acl_ruleset_lookup(acl, block, chain_index);
 if (ruleset) {
  refcount_inc(&ruleset->refcount);
  return ruleset;
 }

 return prestera_acl_ruleset_create(acl, block, chain_index);
}

void prestera_acl_ruleset_put(struct prestera_acl_ruleset *ruleset)
{
 if (!refcount_dec_and_test(&ruleset->refcount))
  return;

 prestera_acl_ruleset_destroy(ruleset);
}

int prestera_acl_ruleset_bind(struct prestera_acl_ruleset *ruleset,
         struct prestera_port *port)
{
 struct prestera_acl_iface iface = {
  .type = PRESTERA_ACL_IFACE_TYPE_PORT,
  .port = port
 };

 return prestera_hw_vtcam_iface_bind(port->sw, &iface, ruleset->vtcam_id,
         ruleset->pcl_id);
}

int prestera_acl_ruleset_unbind(struct prestera_acl_ruleset *ruleset,
    struct prestera_port *port)
{
 struct prestera_acl_iface iface = {
  .type = PRESTERA_ACL_IFACE_TYPE_PORT,
  .port = port
 };

 return prestera_hw_vtcam_iface_unbind(port->sw, &iface,
           ruleset->vtcam_id);
}

static int prestera_acl_ruleset_block_bind(struct prestera_acl_ruleset *ruleset,
        struct prestera_flow_block *block)
{
 struct prestera_flow_block_binding *binding;
 int err;

 block->ruleset_zero = ruleset;
 list_for_each_entry(binding, &block->binding_list, list) {
  err = prestera_acl_ruleset_bind(ruleset, binding->port);
  if (err)
   goto rollback;
 }
 return 0;

rollback:
 list_for_each_entry_continue_reverse(binding, &block->binding_list,
          list)
  err = prestera_acl_ruleset_unbind(ruleset, binding->port);
 block->ruleset_zero = NULL;

 return err;
}

static void
prestera_acl_ruleset_block_unbind(struct prestera_acl_ruleset *ruleset,
      struct prestera_flow_block *block)
{
 struct prestera_flow_block_binding *binding;

 list_for_each_entry(binding, &block->binding_list, list)
  prestera_acl_ruleset_unbind(ruleset, binding->port);
 block->ruleset_zero = NULL;
}

static void
prestera_acl_ruleset_prio_refresh(struct prestera_acl *acl,
      struct prestera_acl_ruleset *ruleset)
{
 struct prestera_acl_rule *rule;

 ruleset->prio.min = UINT_MAX;
 ruleset->prio.max = 0;

 list_for_each_entry(rule, &acl->rules, list) {
  if (ruleset->ingress != rule->ruleset->ingress)
   continue;
  if (ruleset->ht_key.chain_index != rule->chain_index)
   continue;

  ruleset->prio.min = min(ruleset->prio.min, rule->priority);
  ruleset->prio.max = max(ruleset->prio.max, rule->priority);
 }
}

void
prestera_acl_rule_keymask_pcl_id_set(struct prestera_acl_rule *rule, u16 pcl_id)
{
 struct prestera_acl_match *r_match = &rule->re_key.match;
 __be16 pcl_id_mask = htons(PRESTERA_ACL_KEYMASK_PCL_ID);
 __be16 pcl_id_key = htons(pcl_id);

 rule_match_set(r_match->key, PCL_ID, pcl_id_key);
 rule_match_set(r_match->mask, PCL_ID, pcl_id_mask);
}

struct prestera_acl_rule *
prestera_acl_rule_lookup(struct prestera_acl_ruleset *ruleset,
    unsigned long cookie)
{
 return rhashtable_lookup_fast(&ruleset->rule_ht, &cookie,
          prestera_acl_rule_ht_params);
}

u32 prestera_acl_ruleset_index_get(const struct prestera_acl_ruleset *ruleset)
{
 return ruleset->index;
}

void prestera_acl_ruleset_prio_get(struct prestera_acl_ruleset *ruleset,
       u32 *prio_min, u32 *prio_max)
{
 *prio_min = ruleset->prio.min;
 *prio_max = ruleset->prio.max;
}

bool prestera_acl_ruleset_is_offload(struct prestera_acl_ruleset *ruleset)
{
 return ruleset->offload;
}

struct prestera_acl_rule *
prestera_acl_rule_create(struct prestera_acl_ruleset *ruleset,
    unsigned long cookie, u32 chain_index)
{
 struct prestera_acl_rule *rule;

 rule = kzalloc(sizeof(*rule), GFP_KERNEL);
 if (!rule)
  return ERR_PTR(-ENOMEM);

 rule->ruleset = ruleset;
 rule->cookie = cookie;
 rule->chain_index = chain_index;

 refcount_inc(&ruleset->refcount);

 return rule;
}

void prestera_acl_rule_priority_set(struct prestera_acl_rule *rule,
        u32 priority)
{
 rule->priority = priority;
}

void prestera_acl_rule_destroy(struct prestera_acl_rule *rule)
{
 if (rule->jump_ruleset)
  /* release ruleset kept by jump action */
  prestera_acl_ruleset_put(rule->jump_ruleset);

 prestera_acl_ruleset_put(rule->ruleset);
 kfree(rule);
}

static void prestera_acl_ruleset_prio_update(struct prestera_acl_ruleset *ruleset,
          u32 prio)
{
 ruleset->prio.min = min(ruleset->prio.min, prio);
 ruleset->prio.max = max(ruleset->prio.max, prio);
}

int prestera_acl_rule_add(struct prestera_switch *sw,
     struct prestera_acl_rule *rule)
{
 int err;
 struct prestera_acl_ruleset *ruleset = rule->ruleset;
 struct prestera_flow_block *block = ruleset->ht_key.block;

 /* try to add rule to hash table first */
 err = rhashtable_insert_fast(&ruleset->rule_ht, &rule->ht_node,
         prestera_acl_rule_ht_params);
 if (err)
  goto err_ht_insert;

 prestera_acl_rule_keymask_pcl_id_set(rule, ruleset->pcl_id);
 rule->re_arg.vtcam_id = ruleset->vtcam_id;
 rule->re_key.prio = rule->priority;

 rule->re = prestera_acl_rule_entry_find(sw->acl, &rule->re_key);
 err = WARN_ON(rule->re) ? -EEXIST : 0;
 if (err)
  goto err_rule_add;

 rule->re = prestera_acl_rule_entry_create(sw->acl, &rule->re_key,
        &rule->re_arg);
 err = !rule->re ? -EINVAL : 0;
 if (err)
  goto err_rule_add;

 /* bind the block (all ports) to chain index 0, rest of
 * the chains are bound to goto action
 */
 if (!ruleset->ht_key.chain_index && !ruleset->rule_count) {
  err = prestera_acl_ruleset_block_bind(ruleset, block);
  if (err)
   goto err_acl_block_bind;
 }

 list_add_tail(&rule->list, &sw->acl->rules);
 ruleset->rule_count++;
 prestera_acl_ruleset_prio_update(ruleset, rule->priority);
 return 0;

err_acl_block_bind:
 prestera_acl_rule_entry_destroy(sw->acl, rule->re);
err_rule_add:
 rule->re = NULL;
 rhashtable_remove_fast(&ruleset->rule_ht, &rule->ht_node,
          prestera_acl_rule_ht_params);
err_ht_insert:
 return err;
}

void prestera_acl_rule_del(struct prestera_switch *sw,
      struct prestera_acl_rule *rule)
{
 struct prestera_acl_ruleset *ruleset = rule->ruleset;
 struct prestera_flow_block *block = ruleset->ht_key.block;

 rhashtable_remove_fast(&ruleset->rule_ht, &rule->ht_node,
          prestera_acl_rule_ht_params);
 ruleset->rule_count--;
 list_del(&rule->list);

 prestera_acl_rule_entry_destroy(sw->acl, rule->re);
 prestera_acl_ruleset_prio_refresh(sw->acl, ruleset);

 /* unbind block (all ports) */
 if (!ruleset->ht_key.chain_index && !ruleset->rule_count)
  prestera_acl_ruleset_block_unbind(ruleset, block);
}

int prestera_acl_rule_get_stats(struct prestera_acl *acl,
    struct prestera_acl_rule *rule,
    u64 *packets, u64 *bytes, u64 *last_use)
{
 u64 current_packets;
 u64 current_bytes;
 int err;

 err = prestera_counter_stats_get(acl->sw->counter,
      rule->re->counter.block,
      rule->re->counter.id,
      ¤t_packets, ¤t_bytes);
 if (err)
  return err;

 *packets = current_packets;
 *bytes = current_bytes;
 *last_use = jiffies;

 return 0;
}

struct prestera_acl_rule_entry *
prestera_acl_rule_entry_find(struct prestera_acl *acl,
        struct prestera_acl_rule_entry_key *key)
{
 return rhashtable_lookup_fast(&acl->acl_rule_entry_ht, key,
          __prestera_acl_rule_entry_ht_params);
}

static int __prestera_acl_rule_entry2hw_del(struct prestera_switch *sw,
         struct prestera_acl_rule_entry *e)
{
 return prestera_hw_vtcam_rule_del(sw, e->vtcam_id, e->hw_id);
}

static int __prestera_acl_rule_entry2hw_add(struct prestera_switch *sw,
         struct prestera_acl_rule_entry *e)
{
 struct prestera_acl_hw_action_info act_hw[PRESTERA_ACL_RULE_ACTION_MAX];
 int act_num;

 memset(&act_hw, 0, sizeof(act_hw));
 act_num = 0;

 /* accept */
 if (e->accept.valid) {
  act_hw[act_num].id = PRESTERA_ACL_RULE_ACTION_ACCEPT;
  act_num++;
 }
 /* drop */
 if (e->drop.valid) {
  act_hw[act_num].id = PRESTERA_ACL_RULE_ACTION_DROP;
  act_num++;
 }
 /* trap */
 if (e->trap.valid) {
  act_hw[act_num].id = PRESTERA_ACL_RULE_ACTION_TRAP;
  act_num++;
 }
 /* police */
 if (e->police.valid) {
  act_hw[act_num].id = PRESTERA_ACL_RULE_ACTION_POLICE;
  act_hw[act_num].police = e->police.i;
  act_num++;
 }
 /* jump */
 if (e->jump.valid) {
  act_hw[act_num].id = PRESTERA_ACL_RULE_ACTION_JUMP;
  act_hw[act_num].jump = e->jump.i;
  act_num++;
 }
 /* counter */
 if (e->counter.block) {
  act_hw[act_num].id = PRESTERA_ACL_RULE_ACTION_COUNT;
  act_hw[act_num].count.id = e->counter.id;
  act_num++;
 }

 return prestera_hw_vtcam_rule_add(sw, e->vtcam_id, e->key.prio,
       e->key.match.key, e->key.match.mask,
       act_hw, act_num, &e->hw_id);
}

static void
__prestera_acl_rule_entry_act_destruct(struct prestera_switch *sw,
           struct prestera_acl_rule_entry *e)
{
 /* counter */
 prestera_counter_put(sw->counter, e->counter.block, e->counter.id);
 /* police */
 if (e->police.valid)
  prestera_hw_policer_release(sw, e->police.i.id);
}

void prestera_acl_rule_entry_destroy(struct prestera_acl *acl,
         struct prestera_acl_rule_entry *e)
{
 int ret;

 rhashtable_remove_fast(&acl->acl_rule_entry_ht, &e->ht_node,
          __prestera_acl_rule_entry_ht_params);

 ret = __prestera_acl_rule_entry2hw_del(acl->sw, e);
 WARN_ON(ret && ret != -ENODEV);

 __prestera_acl_rule_entry_act_destruct(acl->sw, e);
 kfree(e);
}

static int
__prestera_acl_rule_entry_act_construct(struct prestera_switch *sw,
     struct prestera_acl_rule_entry *e,
     struct prestera_acl_rule_entry_arg *arg)
{
 int err;

 /* accept */
 e->accept.valid = arg->accept.valid;
 /* drop */
 e->drop.valid = arg->drop.valid;
 /* trap */
 e->trap.valid = arg->trap.valid;
 /* jump */
 e->jump.valid = arg->jump.valid;
 e->jump.i = arg->jump.i;
 /* police */
 if (arg->police.valid) {
  u8 type = arg->police.ingress ? PRESTERA_POLICER_TYPE_INGRESS :
      PRESTERA_POLICER_TYPE_EGRESS;

  err = prestera_hw_policer_create(sw, type, &e->police.i.id);
  if (err)
   goto err_out;

  err = prestera_hw_policer_sr_tcm_set(sw, e->police.i.id,
           arg->police.rate,
           arg->police.burst);
  if (err) {
   prestera_hw_policer_release(sw, e->police.i.id);
   goto err_out;
  }
  e->police.valid = arg->police.valid;
 }
 /* counter */
 if (arg->count.valid) {
  err = prestera_counter_get(sw->counter, arg->count.client,
        &e->counter.block,
        &e->counter.id);
  if (err)
   goto err_out;
 }

 return 0;

err_out:
 __prestera_acl_rule_entry_act_destruct(sw, e);
 return -EINVAL;
}

struct prestera_acl_rule_entry *
prestera_acl_rule_entry_create(struct prestera_acl *acl,
          struct prestera_acl_rule_entry_key *key,
          struct prestera_acl_rule_entry_arg *arg)
{
 struct prestera_acl_rule_entry *e;
 int err;

 e = kzalloc(sizeof(*e), GFP_KERNEL);
 if (!e)
  goto err_kzalloc;

 memcpy(&e->key, key, sizeof(*key));
 e->vtcam_id = arg->vtcam_id;
 err = __prestera_acl_rule_entry_act_construct(acl->sw, e, arg);
 if (err)
  goto err_act_construct;

 err = __prestera_acl_rule_entry2hw_add(acl->sw, e);
 if (err)
  goto err_hw_add;

 err = rhashtable_insert_fast(&acl->acl_rule_entry_ht, &e->ht_node,
         __prestera_acl_rule_entry_ht_params);
 if (err)
  goto err_ht_insert;

 return e;

err_ht_insert:
 WARN_ON(__prestera_acl_rule_entry2hw_del(acl->sw, e));
err_hw_add:
 __prestera_acl_rule_entry_act_destruct(acl->sw, e);
err_act_construct:
 kfree(e);
err_kzalloc:
 return NULL;
}

static int __prestera_acl_vtcam_id_try_fit(struct prestera_acl *acl, u8 lookup,
        void *keymask, u32 *vtcam_id)
{
 struct prestera_acl_vtcam *vtcam;
 int i;

 list_for_each_entry(vtcam, &acl->vtcam_list, list) {
  if (lookup != vtcam->lookup)
   continue;

  if (!keymask && !vtcam->is_keymask_set)
   goto vtcam_found;

  if (!(keymask && vtcam->is_keymask_set))
   continue;

  /* try to fit with vtcam keymask */
  for (i = 0; i < __PRESTERA_ACL_RULE_MATCH_TYPE_MAX; i++) {
   __be32 __keymask = ((__be32 *)keymask)[i];

   if (!__keymask)
    /* vtcam keymask in not interested */
    continue;

   if (__keymask & ~vtcam->keymask[i])
    /* keymask does not fit the vtcam keymask */
    break;
  }

  if (i == __PRESTERA_ACL_RULE_MATCH_TYPE_MAX)
   /* keymask fits vtcam keymask, return it */
   goto vtcam_found;
 }

 /* nothing is found */
 return -ENOENT;

vtcam_found:
 refcount_inc(&vtcam->refcount);
 *vtcam_id = vtcam->id;
 return 0;
}

int prestera_acl_vtcam_id_get(struct prestera_acl *acl, u8 lookup, u8 dir,
         void *keymask, u32 *vtcam_id)
{
 struct prestera_acl_vtcam *vtcam;
 u32 new_vtcam_id;
 int err;

 /* find the vtcam that suits keymask. We do not expect to have
 * a big number of vtcams, so, the list type for vtcam list is
 * fine for now
 */
 list_for_each_entry(vtcam, &acl->vtcam_list, list) {
  if (lookup != vtcam->lookup ||
      dir != vtcam->direction)
   continue;

  if (!keymask && !vtcam->is_keymask_set) {
   refcount_inc(&vtcam->refcount);
   goto vtcam_found;
  }

  if (keymask && vtcam->is_keymask_set &&
      !memcmp(keymask, vtcam->keymask, sizeof(vtcam->keymask))) {
   refcount_inc(&vtcam->refcount);
   goto vtcam_found;
  }
 }

 /* vtcam not found, try to create new one */
 vtcam = kzalloc(sizeof(*vtcam), GFP_KERNEL);
 if (!vtcam)
  return -ENOMEM;

 err = prestera_hw_vtcam_create(acl->sw, lookup, keymask, &new_vtcam_id,
           dir);
 if (err) {
  kfree(vtcam);

  /* cannot create new, try to fit into existing vtcam */
  if (__prestera_acl_vtcam_id_try_fit(acl, lookup,
          keymask, &new_vtcam_id))
   return err;

  *vtcam_id = new_vtcam_id;
  return 0;
 }

 vtcam->direction = dir;
 vtcam->id = new_vtcam_id;
 vtcam->lookup = lookup;
 if (keymask) {
  memcpy(vtcam->keymask, keymask, sizeof(vtcam->keymask));
  vtcam->is_keymask_set = true;
 }
 refcount_set(&vtcam->refcount, 1);
 list_add_rcu(&vtcam->list, &acl->vtcam_list);

vtcam_found:
 *vtcam_id = vtcam->id;
 return 0;
}

int prestera_acl_vtcam_id_put(struct prestera_acl *acl, u32 vtcam_id)
{
 struct prestera_acl_vtcam *vtcam;
 int err;

 list_for_each_entry(vtcam, &acl->vtcam_list, list) {
  if (vtcam_id != vtcam->id)
   continue;

  if (!refcount_dec_and_test(&vtcam->refcount))
   return 0;

  err = prestera_hw_vtcam_destroy(acl->sw, vtcam->id);
  if (err && err != -ENODEV) {
   refcount_set(&vtcam->refcount, 1);
   return err;
  }

  list_del(&vtcam->list);
  kfree(vtcam);
  return 0;
 }

 return -ENOENT;
}

int prestera_acl_init(struct prestera_switch *sw)
{
 struct prestera_acl *acl;
 int err;

 acl = kzalloc(sizeof(*acl), GFP_KERNEL);
 if (!acl)
  return -ENOMEM;

 acl->sw = sw;
 INIT_LIST_HEAD(&acl->rules);
 INIT_LIST_HEAD(&acl->vtcam_list);
 idr_init(&acl->uid);

 err = rhashtable_init(&acl->acl_rule_entry_ht,
         &__prestera_acl_rule_entry_ht_params);
 if (err)
  goto err_acl_rule_entry_ht_init;

 err = rhashtable_init(&acl->ruleset_ht,
         &prestera_acl_ruleset_ht_params);
 if (err)
  goto err_ruleset_ht_init;

 sw->acl = acl;

 return 0;

err_ruleset_ht_init:
 rhashtable_destroy(&acl->acl_rule_entry_ht);
err_acl_rule_entry_ht_init:
 kfree(acl);
 return err;
}

void prestera_acl_fini(struct prestera_switch *sw)
{
 struct prestera_acl *acl = sw->acl;

 WARN_ON(!idr_is_empty(&acl->uid));
 idr_destroy(&acl->uid);

 WARN_ON(!list_empty(&acl->vtcam_list));
 WARN_ON(!list_empty(&acl->rules));

 rhashtable_destroy(&acl->ruleset_ht);
 rhashtable_destroy(&acl->acl_rule_entry_ht);

 kfree(acl);
}