[ovs-dev] Multiple ARP cache entries for one same dest IP?

[Darrell Ball]

On Wed, Aug 2, 2017 at 3:51 PM, Joo Kim <itsolution at gmail.com> wrote:

> Hello,
>
> In OVS userspace implementation(See below), looks like, given a dest IP,
> multiple ARP entries are allowed as long as bridge-names are different for
> the same dest IP.
> But, is there real scenario where multiple ARP entries for the same dest IP
> (because of different bridge-name)?
>


link-local addresses is one way
routing space segmentation is another



>
>
> int
> tnl_neigh_lookup(const char br_name[IFNAMSIZ], const struct in6_addr *dst,
>                  struct eth_addr *mac)
> {
>     struct tnl_neigh_entry *neigh;
>     int res = ENOENT;
>     neigh = tnl_neigh_lookup__(br_name, dst);
>     if (neigh) {
>         *mac = neigh->mac;
>         res = 0;
>     }
>     return res;
> }
>
> static struct tnl_neigh_entry *
> tnl_neigh_lookup__(const char br_name[IFNAMSIZ], const struct in6_addr
> *dst)
> {
>     struct tnl_neigh_entry *neigh;
>     uint32_t hash;
>     hash = tnl_neigh_hash(dst);
>     CMAP_FOR_EACH_WITH_HASH (neigh, cmap_node, hash, &table) {
>         if (ipv6_addr_equals(&neigh->ip, dst) && !strcmp(neigh->br_name,
> br_name)) {
>             neigh->expires = time_now() + NEIGH_ENTRY_DEFAULT_IDLE_TIME;
>             return neigh;
>         }
>     }
>     return NULL;
> }
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