mpoa_caches.c

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#include <linux/types.h>
#include <linux/atmmpc.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 printk    /* debug */
#else
#define dprintk(format,args...)
#endif

#if 0
#define ddprintk printk  /* more debug */
#else
#define ddprintk(format,args...)
#endif

static in_cache_entry *in_cache_get(uint32_t 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(uint32_t dst_ip,
					      struct mpoa_client *client,
					      uint32_t 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(uint32_t dst_ip,
					  struct mpoa_client *client)
{
	unsigned char *ip __attribute__ ((unused)) = (unsigned char *)&dst_ip;
	in_cache_entry* entry = kmalloc(sizeof(in_cache_entry), GFP_KERNEL);

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

	dprintk("mpoa: mpoa_caches.c: adding an ingress entry, ip = %u.%u.%u.%u\n", ip[0], ip[1], ip[2], ip[3]);
	memset(entry,0,sizeof(in_cache_entry));

	atomic_set(&entry->use, 1);
	dprintk("mpoa: mpoa_caches.c: 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("mpoa: mpoa_caches.c: 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){
		unsigned char *ip __attribute__ ((unused)) =
		    (unsigned char *)&entry->ctrl_info.in_dst_ip;

		dprintk("mpoa: (%s) mpoa_caches.c: threshold exceeded for ip %u.%u.%u.%u, sending MPOA res req\n", mpc->dev->name, ip[0], ip[1], ip[2], ip[3]);
		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);
	}

	return;
}

/*
 * 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;
	unsigned char *ip;

	vcc = entry->shortcut;
	ip = (unsigned char *)&entry->ctrl_info.in_dst_ip;
	dprintk("mpoa: mpoa_caches.c: removing an ingress entry, ip = %u.%u.%u.%u\n",ip[0], ip[1], ip[2], ip[3]);

	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;
		}
		atm_async_release_vcc(vcc, -EPIPE);
	}

	return;
}


/* Call this every MPC-p2 seconds... Not exactly correct solution,
   but an easy one... */
static void clear_count_and_expired(struct mpoa_client *client)
{
	unsigned char *ip;
	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){
			ip = (unsigned char*)&entry->ctrl_info.in_dst_ip;
			dprintk("mpoa: mpoa_caches.c: holding time expired, ip = %u.%u.%u.%u\n", NIPQUAD(ip));
			client->in_ops->remove_entry(entry, client);
		}
		entry = next_entry;
	}
	write_unlock_bh(&client->ingress_lock);

	return;
}

/* 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 );
				if(entry->retry_time > client->parameters.mpc_p5){
					/* Retry time maximum exceeded, put entry in hold down. */
					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));
			}
		}