Quelle  mpoa_caches.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0
#include <linux/types.h>
#include <linux/atmmpc.h>
#include <linux/slab.h>
#include <linux/time.h>

#include "mpoa_caches.h"
#include "mpc.h"

/*
 * mpoa_caches.c: Implementation of ingress and egress cache
 * handling functions
 */

#if 0
#define dprintk(format, args...)     \
 printk(KERN_DEBUG "mpoa:%s: " format, __FILE__, ##args)  /* debug */
#else
#define dprintk(format, args...)     \
 do { if (0)       \
  printk(KERN_DEBUG "mpoa:%s: " format, __FILE__, ##args);\
 } while (0)
#endif

#if 0
#define ddprintk(format, args...)     \
 printk(KERN_DEBUG "mpoa:%s: " format, __FILE__, ##args)  /* debug */
#else
#define ddprintk(format, args...)     \
 do { if (0)       \
  printk(KERN_DEBUG "mpoa:%s: " format, __FILE__, ##args);\
 } while (0)
#endif

static in_cache_entry *in_cache_get(__be32 dst_ip,
        struct mpoa_client *client)
{
 in_cache_entry *entry;

 read_lock_bh(&client->ingress_lock);
 entry = client->in_cache;
 while (entry != NULL) {
  if (entry->ctrl_info.in_dst_ip == dst_ip) {
   refcount_inc(&entry->use);
   read_unlock_bh(&client->ingress_lock);
   return entry;
  }
  entry = entry->next;
 }
 read_unlock_bh(&client->ingress_lock);

 return NULL;
}

static in_cache_entry *in_cache_get_with_mask(__be32 dst_ip,
           struct mpoa_client *client,
           __be32 mask)
{
 in_cache_entry *entry;

 read_lock_bh(&client->ingress_lock);
 entry = client->in_cache;
 while (entry != NULL) {
  if ((entry->ctrl_info.in_dst_ip & mask) == (dst_ip & mask)) {
   refcount_inc(&entry->use);
   read_unlock_bh(&client->ingress_lock);
   return entry;
  }
  entry = entry->next;
 }
 read_unlock_bh(&client->ingress_lock);

 return NULL;

}

static in_cache_entry *in_cache_get_by_vcc(struct atm_vcc *vcc,
        struct mpoa_client *client)
{
 in_cache_entry *entry;

 read_lock_bh(&client->ingress_lock);
 entry = client->in_cache;
 while (entry != NULL) {
  if (entry->shortcut == vcc) {
   refcount_inc(&entry->use);
   read_unlock_bh(&client->ingress_lock);
   return entry;
  }
  entry = entry->next;
 }
 read_unlock_bh(&client->ingress_lock);

 return NULL;
}

static in_cache_entry *in_cache_add_entry(__be32 dst_ip,
       struct mpoa_client *client)
{
 in_cache_entry *entry = kzalloc(sizeof(in_cache_entry), GFP_KERNEL);

 if (entry == NULL) {
  pr_info("mpoa: mpoa_caches.c: new_in_cache_entry: out of memory\n");
  return NULL;
 }

 dprintk("adding an ingress entry, ip = %pI4\n", &dst_ip);

 refcount_set(&entry->use, 1);
 dprintk("new_in_cache_entry: about to lock\n");
 write_lock_bh(&client->ingress_lock);
 entry->next = client->in_cache;
 entry->prev = NULL;
 if (client->in_cache != NULL)
  client->in_cache->prev = entry;
 client->in_cache = entry;

 memcpy(entry->MPS_ctrl_ATM_addr, client->mps_ctrl_addr, ATM_ESA_LEN);
 entry->ctrl_info.in_dst_ip = dst_ip;
 entry->time = ktime_get_seconds();
 entry->retry_time = client->parameters.mpc_p4;
 entry->count = 1;
 entry->entry_state = INGRESS_INVALID;
 entry->ctrl_info.holding_time = HOLDING_TIME_DEFAULT;
 refcount_inc(&entry->use);

 write_unlock_bh(&client->ingress_lock);
 dprintk("new_in_cache_entry: unlocked\n");

 return entry;
}

static int cache_hit(in_cache_entry *entry, struct mpoa_client *mpc)
{
 struct atm_mpoa_qos *qos;
 struct k_message msg;

 entry->count++;
 if (entry->entry_state == INGRESS_RESOLVED && entry->shortcut != NULL)
  return OPEN;

 if (entry->entry_state == INGRESS_REFRESHING) {
  if (entry->count > mpc->parameters.mpc_p1) {
   msg.type = SND_MPOA_RES_RQST;
   msg.content.in_info = entry->ctrl_info;
   memcpy(msg.MPS_ctrl, mpc->mps_ctrl_addr, ATM_ESA_LEN);
   qos = atm_mpoa_search_qos(entry->ctrl_info.in_dst_ip);
   if (qos != NULL)
    msg.qos = qos->qos;
   msg_to_mpoad(&msg, mpc);
   entry->reply_wait = ktime_get_seconds();
   entry->entry_state = INGRESS_RESOLVING;
  }
  if (entry->shortcut != NULL)
   return OPEN;
  return CLOSED;
 }

 if (entry->entry_state == INGRESS_RESOLVING && entry->shortcut != NULL)
  return OPEN;

 if (entry->count > mpc->parameters.mpc_p1 &&
     entry->entry_state == INGRESS_INVALID) {
  dprintk("(%s) threshold exceeded for ip %pI4, sending MPOA res req\n",
   mpc->dev->name, &entry->ctrl_info.in_dst_ip);
  entry->entry_state = INGRESS_RESOLVING;
  msg.type = SND_MPOA_RES_RQST;
  memcpy(msg.MPS_ctrl, mpc->mps_ctrl_addr, ATM_ESA_LEN);
  msg.content.in_info = entry->ctrl_info;
  qos = atm_mpoa_search_qos(entry->ctrl_info.in_dst_ip);
  if (qos != NULL)
   msg.qos = qos->qos;
  msg_to_mpoad(&msg, mpc);
  entry->reply_wait = ktime_get_seconds();
 }

 return CLOSED;
}

static void in_cache_put(in_cache_entry *entry)
{
 if (refcount_dec_and_test(&entry->use)) {
  kfree_sensitive(entry);
 }
}

/*
 * This should be called with write lock on
 */
static void in_cache_remove_entry(in_cache_entry *entry,
      struct mpoa_client *client)
{
 struct atm_vcc *vcc;
 struct k_message msg;

 vcc = entry->shortcut;
 dprintk("removing an ingress entry, ip = %pI4\n",
  &entry->ctrl_info.in_dst_ip);

 if (entry->prev != NULL)
  entry->prev->next = entry->next;
 else
  client->in_cache = entry->next;
 if (entry->next != NULL)
  entry->next->prev = entry->prev;
 client->in_ops->put(entry);
 if (client->in_cache == NULL && client->eg_cache == NULL) {
  msg.type = STOP_KEEP_ALIVE_SM;
  msg_to_mpoad(&msg, client);
 }

 /* Check if the egress side still uses this VCC */
 if (vcc != NULL) {
  eg_cache_entry *eg_entry = client->eg_ops->get_by_vcc(vcc,
              client);
  if (eg_entry != NULL) {
   client->eg_ops->put(eg_entry);
   return;
  }
  vcc_release_async(vcc, -EPIPE);
 }
}

/* Call this every MPC-p2 seconds... Not exactly correct solution,
   but an easy one... */
static void clear_count_and_expired(struct mpoa_client *client)
{
 in_cache_entry *entry, *next_entry;
 time64_t now;

 now = ktime_get_seconds();

 write_lock_bh(&client->ingress_lock);
 entry = client->in_cache;
 while (entry != NULL) {
  entry->count = 0;
  next_entry = entry->next;
  if ((now - entry->time) > entry->ctrl_info.holding_time) {
   dprintk("holding time expired, ip = %pI4\n",
    &entry->ctrl_info.in_dst_ip);
   client->in_ops->remove_entry(entry, client);
  }
  entry = next_entry;
 }
 write_unlock_bh(&client->ingress_lock);
}

/* Call this every MPC-p4 seconds. */
static void check_resolving_entries(struct mpoa_client *client)
{

 struct atm_mpoa_qos *qos;
 in_cache_entry *entry;
 time64_t now;
 struct k_message msg;

 now = ktime_get_seconds();

 read_lock_bh(&client->ingress_lock);
 entry = client->in_cache;
 while (entry != NULL) {
  if (entry->entry_state == INGRESS_RESOLVING) {

   if ((now - entry->hold_down)
     < client->parameters.mpc_p6) {
    entry = entry->next; /* Entry in hold down */
    continue;
   }
   if ((now - entry->reply_wait) > entry->retry_time) {
    entry->retry_time = MPC_C1 * (entry->retry_time);
    /*
 * Retry time maximum exceeded,
 * put entry in hold down.
 */
    if (entry->retry_time > client->parameters.mpc_p5) {
     entry->hold_down = ktime_get_seconds();
     entry->retry_time = client->parameters.mpc_p4;
     entry = entry->next;
     continue;
    }
    /* Ask daemon to send a resolution request. */
    memset(&entry->hold_down, 0, sizeof(time64_t));
    msg.type = SND_MPOA_RES_RTRY;
    memcpy(msg.MPS_ctrl, client->mps_ctrl_addr, ATM_ESA_LEN);
    msg.content.in_info = entry->ctrl_info;
    qos = atm_mpoa_search_qos(entry->ctrl_info.in_dst_ip);
    if (qos != NULL)
     msg.qos = qos->qos;
    msg_to_mpoad(&msg, client);
    entry->reply_wait = ktime_get_seconds();
   }
  }
  entry = entry->next;
 }
 read_unlock_bh(&client->ingress_lock);
}

/* Call this every MPC-p5 seconds. */
static void refresh_entries(struct mpoa_client *client)
{
 time64_t now;
 struct in_cache_entry *entry = client->in_cache;

 ddprintk("refresh_entries\n");
 now = ktime_get_seconds();

 read_lock_bh(&client->ingress_lock);
 while (entry != NULL) {
  if (entry->entry_state == INGRESS_RESOLVED) {
   if (!(entry->refresh_time))
    entry->refresh_time = (2 * (entry->ctrl_info.holding_time))/3;
   if ((now - entry->reply_wait) >
       entry->refresh_time) {
    dprintk("refreshing an entry.\n");
    entry->entry_state = INGRESS_REFRESHING;

   }
  }
  entry = entry->next;
 }
 read_unlock_bh(&client->ingress_lock);
}

static void in_destroy_cache(struct mpoa_client *mpc)
{
 write_lock_irq(&mpc->ingress_lock);
 while (mpc->in_cache != NULL)
  mpc->in_ops->remove_entry(mpc->in_cache, mpc);
 write_unlock_irq(&mpc->ingress_lock);
}

static eg_cache_entry *eg_cache_get_by_cache_id(__be32 cache_id,
      struct mpoa_client *mpc)
{
 eg_cache_entry *entry;

 read_lock_irq(&mpc->egress_lock);
 entry = mpc->eg_cache;
 while (entry != NULL) {
  if (entry->ctrl_info.cache_id == cache_id) {
   refcount_inc(&entry->use);
   read_unlock_irq(&mpc->egress_lock);
   return entry;
  }
  entry = entry->next;
 }
 read_unlock_irq(&mpc->egress_lock);

 return NULL;
}

/* This can be called from any context since it saves CPU flags */
static eg_cache_entry *eg_cache_get_by_tag(__be32 tag, struct mpoa_client *mpc)
{
 unsigned long flags;
 eg_cache_entry *entry;

 read_lock_irqsave(&mpc->egress_lock, flags);
 entry = mpc->eg_cache;
 while (entry != NULL) {
  if (entry->ctrl_info.tag == tag) {
   refcount_inc(&entry->use);
   read_unlock_irqrestore(&mpc->egress_lock, flags);
   return entry;
  }
  entry = entry->next;
 }
 read_unlock_irqrestore(&mpc->egress_lock, flags);

 return NULL;
}

/* This can be called from any context since it saves CPU flags */
static eg_cache_entry *eg_cache_get_by_vcc(struct atm_vcc *vcc,
        struct mpoa_client *mpc)
{
 unsigned long flags;
 eg_cache_entry *entry;

 read_lock_irqsave(&mpc->egress_lock, flags);
 entry = mpc->eg_cache;
 while (entry != NULL) {
  if (entry->shortcut == vcc) {
   refcount_inc(&entry->use);
   read_unlock_irqrestore(&mpc->egress_lock, flags);
   return entry;
  }
  entry = entry->next;
 }
 read_unlock_irqrestore(&mpc->egress_lock, flags);

 return NULL;
}

static eg_cache_entry *eg_cache_get_by_src_ip(__be32 ipaddr,
           struct mpoa_client *mpc)
{
 eg_cache_entry *entry;

 read_lock_irq(&mpc->egress_lock);
 entry = mpc->eg_cache;
 while (entry != NULL) {
  if (entry->latest_ip_addr == ipaddr) {
   refcount_inc(&entry->use);
   read_unlock_irq(&mpc->egress_lock);
   return entry;
  }
  entry = entry->next;
 }
 read_unlock_irq(&mpc->egress_lock);

 return NULL;
}

static void eg_cache_put(eg_cache_entry *entry)
{
 if (refcount_dec_and_test(&entry->use)) {
  kfree_sensitive(entry);
 }
}

/*
 * This should be called with write lock on
 */
static void eg_cache_remove_entry(eg_cache_entry *entry,
      struct mpoa_client *client)
{
 struct atm_vcc *vcc;
 struct k_message msg;

 vcc = entry->shortcut;
 dprintk("removing an egress entry.\n");
 if (entry->prev != NULL)
  entry->prev->next = entry->next;
 else
  client->eg_cache = entry->next;
 if (entry->next != NULL)
  entry->next->prev = entry->prev;
 client->eg_ops->put(entry);
 if (client->in_cache == NULL && client->eg_cache == NULL) {
  msg.type = STOP_KEEP_ALIVE_SM;
  msg_to_mpoad(&msg, client);
 }

 /* Check if the ingress side still uses this VCC */
 if (vcc != NULL) {
  in_cache_entry *in_entry = client->in_ops->get_by_vcc(vcc, client);
  if (in_entry != NULL) {
   client->in_ops->put(in_entry);
   return;
  }
  vcc_release_async(vcc, -EPIPE);
 }
}

static eg_cache_entry *eg_cache_add_entry(struct k_message *msg,
       struct mpoa_client *client)
{
 eg_cache_entry *entry = kzalloc(sizeof(eg_cache_entry), GFP_KERNEL);

 if (entry == NULL) {
  pr_info("out of memory\n");
  return NULL;
 }

 dprintk("adding an egress entry, ip = %pI4, this should be our IP\n",
  &msg->content.eg_info.eg_dst_ip);

 refcount_set(&entry->use, 1);
 dprintk("new_eg_cache_entry: about to lock\n");
 write_lock_irq(&client->egress_lock);
 entry->next = client->eg_cache;
 entry->prev = NULL;
 if (client->eg_cache != NULL)
  client->eg_cache->prev = entry;
 client->eg_cache = entry;

 memcpy(entry->MPS_ctrl_ATM_addr, client->mps_ctrl_addr, ATM_ESA_LEN);
 entry->ctrl_info = msg->content.eg_info;
 entry->time = ktime_get_seconds();
 entry->entry_state = EGRESS_RESOLVED;
 dprintk("new_eg_cache_entry cache_id %u\n",
  ntohl(entry->ctrl_info.cache_id));
 dprintk("mps_ip = %pI4\n", &entry->ctrl_info.mps_ip);
 refcount_inc(&entry->use);

 write_unlock_irq(&client->egress_lock);
 dprintk("new_eg_cache_entry: unlocked\n");

 return entry;
}

static void update_eg_cache_entry(eg_cache_entry *entry, uint16_t holding_time)
{
 entry->time = ktime_get_seconds();
 entry->entry_state = EGRESS_RESOLVED;
 entry->ctrl_info.holding_time = holding_time;
}

static void clear_expired(struct mpoa_client *client)
{
 eg_cache_entry *entry, *next_entry;
 time64_t now;
 struct k_message msg;

 now = ktime_get_seconds();

 write_lock_irq(&client->egress_lock);
 entry = client->eg_cache;
 while (entry != NULL) {
  next_entry = entry->next;
  if ((now - entry->time) > entry->ctrl_info.holding_time) {
   msg.type = SND_EGRESS_PURGE;
   msg.content.eg_info = entry->ctrl_info;
   dprintk("egress_cache: holding time expired, cache_id = %u.\n",
    ntohl(entry->ctrl_info.cache_id));
   msg_to_mpoad(&msg, client);
   client->eg_ops->remove_entry(entry, client);
  }
  entry = next_entry;
 }
 write_unlock_irq(&client->egress_lock);
}

static void eg_destroy_cache(struct mpoa_client *mpc)
{
 write_lock_irq(&mpc->egress_lock);
 while (mpc->eg_cache != NULL)
  mpc->eg_ops->remove_entry(mpc->eg_cache, mpc);
 write_unlock_irq(&mpc->egress_lock);
}


static const struct in_cache_ops ingress_ops = {
 .add_entry = in_cache_add_entry,
 .get = in_cache_get,
 .get_with_mask = in_cache_get_with_mask,
 .get_by_vcc = in_cache_get_by_vcc,
 .put = in_cache_put,
 .remove_entry = in_cache_remove_entry,
 .cache_hit = cache_hit,
 .clear_count = clear_count_and_expired,
 .check_resolving = check_resolving_entries,
 .refresh = refresh_entries,
 .destroy_cache = in_destroy_cache
};

static const struct eg_cache_ops egress_ops = {
 .add_entry = eg_cache_add_entry,
 .get_by_cache_id = eg_cache_get_by_cache_id,
 .get_by_tag = eg_cache_get_by_tag,
 .get_by_vcc = eg_cache_get_by_vcc,
 .get_by_src_ip = eg_cache_get_by_src_ip,
 .put = eg_cache_put,
 .remove_entry = eg_cache_remove_entry,
 .update = update_eg_cache_entry,
 .clear_expired = clear_expired,
 .destroy_cache = eg_destroy_cache
};

void atm_mpoa_init_cache(struct mpoa_client *mpc)
{
 mpc->in_ops = &ingress_ops;
 mpc->eg_ops = &egress_ops;
}