From: Ben Pfaff Date: Mon, 18 Aug 2008 22:01:35 +0000 (-0700) Subject: Un-learn the port on which a MAC is located after some time. X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=95eb308262ccca7b9e613f88cfc435a662cfb2a9;p=openvswitch Un-learn the port on which a MAC is located after some time. Otherwise, we can send frames the wrong port indefinitely, if the device in question does not itself initiate sending data. --- diff --git a/lib/mac-learning.c b/lib/mac-learning.c index 29a66f1b..ad3a0b8d 100644 --- a/lib/mac-learning.c +++ b/lib/mac-learning.c @@ -41,6 +41,7 @@ #include "hash.h" #include "list.h" #include "openflow.h" +#include "timeval.h" #include "util.h" #define THIS_MODULE VLM_mac_learning @@ -56,8 +57,9 @@ struct mac_entry { struct list hash_node; /* Element in a mac_learning 'table' list. */ struct list lru_node; /* Element in mac_learning 'lrus' list. */ + time_t used; /* Last used time. */ uint8_t mac[ETH_ADDR_LEN]; /* Known MAC address. */ - uint16_t port; /* Port on which MAC was most recently seen. */ + int port; /* Port on which MAC was most recently seen. */ }; /* MAC learning table. */ @@ -126,7 +128,6 @@ mac_learning_learn(struct mac_learning *ml, struct mac_entry *e; struct list *bucket; - assert(src_port != OFPP_FLOOD); if (eth_addr_is_multicast(src_mac)) { VLOG_DBG("multicast packet source "ETH_ADDR_FMT, ETH_ADDR_ARGS(src_mac)); @@ -135,29 +136,27 @@ mac_learning_learn(struct mac_learning *ml, bucket = mac_table_bucket(ml, src_mac); e = search_bucket(bucket, src_mac); - if (e) { - /* Make 'e' most-recently-used. */ - list_remove(&e->lru_node); - list_push_back(&ml->lrus, &e->lru_node); - if (e->port == src_port) { - return false; - } - } else { - /* Learn a new address. - * First drop the least recently used mac source. */ + if (!e) { e = CONTAINER_OF(ml->lrus.next, struct mac_entry, lru_node); + memcpy(e->mac, src_mac, ETH_ADDR_LEN); if (e->hash_node.next) { list_remove(&e->hash_node); } - list_remove(&e->lru_node); - - /* Create new mac source. */ - memcpy(e->mac, src_mac, ETH_ADDR_LEN); list_push_front(bucket, &e->hash_node); - list_push_back(&ml->lrus, &e->lru_node); + e->port = -1; + } + + /* Make the entry most-recently-used. */ + list_remove(&e->lru_node); + list_push_back(&ml->lrus, &e->lru_node); + e->used = time_now(); + + /* Did we learn something? */ + if (e->port != src_port) { + e->port = src_port; + return true; } - e->port = src_port; - return true; + return false; } /* Looks up address 'dst' in 'ml'. Returns the port on which a frame destined @@ -168,7 +167,7 @@ mac_learning_lookup(const struct mac_learning *ml, { if (!eth_addr_is_multicast(dst)) { struct mac_entry *e = search_bucket(mac_table_bucket(ml, dst), dst); - if (e) { + if (e && time_now() - e->used < 60) { return e->port; } }