/* Attempts to make 'ml' learn from the fact that a frame from 'src_mac' was
* just observed arriving from 'src_port' on the given 'vlan'.
*
* Returns nonzero if we actually learned something from this, zero if it just
* confirms what we already knew. The nonzero return value is the tag of flows
* that now need revalidation.
*
* The 'vlan' parameter is used to maintain separate per-VLAN learning tables.
* Specify 0 if this behavior is undesirable.
*
* 'lock_type' specifies whether the entry should be locked or existing locks
* are check. */
tag_type
mac_learning_learn(struct mac_learning *ml,
const uint8_t src_mac[ETH_ADDR_LEN], uint16_t vlan,
uint16_t src_port, enum grat_arp_lock_type lock_type)
{
struct mac_entry *e;
struct list *bucket;
if (!is_learning_vlan(ml, vlan)) {
return 0;
}
if (eth_addr_is_multicast(src_mac)) {
static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(30, 30);
VLOG_DBG_RL(&rl, "multicast packet source "ETH_ADDR_FMT,
ETH_ADDR_ARGS(src_mac));
return 0;
}
bucket = mac_table_bucket(ml, src_mac, vlan);
e = search_bucket(bucket, src_mac, vlan);
if (!e) {
if (!list_is_empty(&ml->free)) {
e = mac_entry_from_lru_node(ml->free.next);
} else {
e = mac_entry_from_lru_node(ml->lrus.next);
list_remove(&e->hash_node);
}
memcpy(e->mac, src_mac, ETH_ADDR_LEN);
list_push_front(bucket, &e->hash_node);
e->port = -1;
e->vlan = vlan;
e->tag = make_unknown_mac_tag(ml, src_mac, vlan);
e->grat_arp_lock = TIME_MIN;
}
if (lock_type != GRAT_ARP_LOCK_CHECK || time_now() >= e->grat_arp_lock) {
/* Make the entry most-recently-used. */
list_remove(&e->lru_node);
list_push_back(&ml->lrus, &e->lru_node);
e->expires = time_now() + MAC_ENTRY_IDLE_TIME;
if (lock_type == GRAT_ARP_LOCK_SET) {
e->grat_arp_lock = time_now() + MAC_GRAT_ARP_LOCK_TIME;
}
/* Did we learn something? */
if (e->port != src_port) {
tag_type old_tag = e->tag;
e->port = src_port;
e->tag = tag_create_random();
COVERAGE_INC(mac_learning_learned);
return old_tag;
}
}
return 0;
}
static Block_t *
get_free_block(Allctr_t *allctr, Uint size,
Block_t *cand_blk, Uint cand_size)
{
GFAllctr_t *gfallctr = (GFAllctr_t *) allctr;
int unsafe_bi, min_bi;
Block_t *blk;
ASSERT(!cand_blk || cand_size >= size);
unsafe_bi = BKT_IX(gfallctr, size);
min_bi = find_bucket(&gfallctr->bucket_mask, unsafe_bi);
if (min_bi < 0)
return NULL;
if (min_bi == unsafe_bi) {
blk = search_bucket(allctr, min_bi, size);
if (blk) {
if (cand_blk && cand_size <= MBC_FBLK_SZ(blk))
return NULL; /* cand_blk was better */
unlink_free_block(allctr, blk);
return blk;
}
if (min_bi < NO_OF_BKTS - 1) {
min_bi = find_bucket(&gfallctr->bucket_mask, min_bi + 1);
if (min_bi < 0)
return NULL;
}
else
return NULL;
}
else {
ASSERT(min_bi > unsafe_bi);
}
/* We are guaranteed to find a block that fits in this bucket */
blk = search_bucket(allctr, min_bi, size);
ASSERT(blk);
if (cand_blk && cand_size <= MBC_FBLK_SZ(blk))
return NULL; /* cand_blk was better */
unlink_free_block(allctr, blk);
return blk;
}
/* Looks up MAC 'dst' for VLAN 'vlan' in 'ml'. Returns the port on which a
* frame destined for 'dst' should be sent, -1 if unknown.
*
* Adds to '*tag' (which the caller must have initialized) the tag that should
* be attached to any flow created based on the return value, if any, to allow
* those flows to be revalidated when the MAC learning entry changes.
*
* 'is_grat_arp_locked' is an optional parameter that returns whether the entry
* is currently locked.*/
int
mac_learning_lookup_tag(const struct mac_learning *ml,
const uint8_t dst[ETH_ADDR_LEN], uint16_t vlan,
tag_type *tag, bool *is_grat_arp_locked)
{
if (eth_addr_is_multicast(dst) || !is_learning_vlan(ml, vlan)) {
return -1;
} else {
struct mac_entry *e = search_bucket(mac_table_bucket(ml, dst, vlan),
dst, vlan);
if (e) {
*tag |= e->tag;
if (is_grat_arp_locked) {
*is_grat_arp_locked = time_now() < e->grat_arp_lock;
}
return e->port;
} else {
*tag |= make_unknown_mac_tag(ml, dst, vlan);
return -1;
}
}
}
