mpoa_caches.c

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#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) {
            atomic_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)) {
            atomic_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) {
            atomic_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);

    atomic_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;
    do_gettimeofday(&(entry->tv));
    entry->retry_time = client->parameters.mpc_p4;
    entry->count = 1;
    entry->entry_state = INGRESS_INVALID;
    entry->ctrl_info.holding_time = HOLDING_TIME_DEFAULT;
    atomic_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);
            do_gettimeofday(&(entry->reply_wait));
            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);
        do_gettimeofday(&(entry->reply_wait));
    }

    return CLOSED;
}

static void in_cache_put(in_cache_entry *entry)
{
    if (atomic_dec_and_test(&entry->use)) {
        memset(entry, 0, sizeof(in_cache_entry));
        kfree(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;
    struct timeval now;

    do_gettimeofday(&now);

    write_lock_bh(&client->ingress_lock);
    entry = client->in_cache;
    while (entry != NULL) {
        entry->count = 0;
        next_entry = entry->next;
        if ((now.tv_sec - entry->tv.tv_sec)
           > 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;
    struct timeval now;
    struct k_message msg;

    do_gettimeofday(&now);

    read_lock_bh(&client->ingress_lock);
    entry = client->in_cache;
    while (entry != NULL) {
        if (entry->entry_state == INGRESS_RESOLVING) {
            if ((now.tv_sec - entry->hold_down.tv_sec) <
                client->parameters.mpc_p6) {
                entry = entry->next;    /* Entry in hold down */
                continue;
            }
            if ((now.tv_sec - entry->reply_wait.tv_sec) >
                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) {
                    do_gettimeofday(&(entry->hold_down));
                    entry->retry_time = client->parameters.mpc_p4;
                    entry = entry->next;
                    continue;
                }
                /* Ask daemon to send a resolution request. */
                memset(&(entry->hold_down), 0, sizeof(struct timeval));
                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);
                do_gettimeofday(&(entry->reply_wait));
            }
        }
        entry = entry->next;
    }
    read_unlock_bh(&client->ingress_lock);
}

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

    ddprintk("refresh_entries\n");
    do_gettimeofday(&now);

    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.tv_sec - entry->reply_wait.tv_sec) >
                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) {
            atomic_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) {
            atomic_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) {
            atomic_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) {
            atomic_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 (atomic_dec_and_test(&entry->use)) {
        memset(entry, 0, sizeof(eg_cache_entry));
        kfree(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);

    atomic_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;
    do_gettimeofday(&(entry->tv));
    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);
    atomic_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)
{
    do_gettimeofday(&(entry->tv));
    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;
    struct timeval now;
    struct k_message msg;

    do_gettimeofday(&now);

    write_lock_irq(&client->egress_lock);
    entry = client->eg_cache;
    while (entry != NULL) {
        next_entry = entry->next;
        if ((now.tv_sec - entry->tv.tv_sec)
           > 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 struct in_cache_ops ingress_ops = {
    in_cache_add_entry,               /* add_entry       */
    in_cache_get,                     /* get             */
    in_cache_get_with_mask,           /* get_with_mask   */
    in_cache_get_by_vcc,              /* get_by_vcc      */
    in_cache_put,                     /* put             */
    in_cache_remove_entry,            /* remove_entry    */
    cache_hit,                        /* cache_hit       */
    clear_count_and_expired,          /* clear_count     */
    check_resolving_entries,          /* check_resolving */
    refresh_entries,                  /* refresh         */
    in_destroy_cache                  /* destroy_cache   */
};

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


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