On Sat, May 11, 2013 at 07:23:27PM +0200, Linus Lüssing wrote: > With this patch a multicast packet is not always simply flooded anymore, > the bevahiour for the following cases is changed to reduce > unnecessary overhead: > > If all nodes within the horizon of a certain node have signalized > multicast listener announcement capability > (BATADV_MCAST_LISTENER_ANNOUNCEMENT) then an IPv6 multicast packet > with a destination of IPv6 link-local scope coming from the upstream > of this node... > > * ...is dropped if there is no according multicast listener in the > translation table. > * ...is forwarded via unicast if there is a single node with interested > multicast listeners. >
othwerwise? Does it get flooded like now if there is more than one receiver?
>
> /**
> + * batadv_mcast_flood - Checks on how to forward a multicast packet
> + * @skb: The multicast packet to check
> + * @bat_priv: the bat priv with all the soft interface information
> + *
> + * Returns 1 if the packet should be flooded, 0 if it should be forwarded
> + * via unicast or -1 if it should be drooped.
> + */
> +int batadv_mcast_flood(struct sk_buff *skb, struct batadv_priv *bat_priv)
> +{
> + struct ethhdr *ethhdr = (struct ethhdr *)(skb->data);
> + struct ipv6hdr *ip6hdr;
> + int count, ret = 1;
> +
> + if (atomic_read(&bat_priv->mcast_group_awareness) &&
> + !atomic_read(&bat_priv->mcast_num_non_aware) &&
> + ntohs(ethhdr->h_proto) == ETH_P_IPV6) {
mh..this would not work for VLANs..did you plan to introduce support for VLANs
later? or you simply overlooked it? :)
> + if (!pskb_may_pull(skb, sizeof(*ethhdr) + sizeof(*ip6hdr))) {
> + ret = -1;
> + goto out;
> + }
> +
> + ip6hdr = ipv6_hdr(skb);
> +
> + /* TODO: Implement Multicast Router Discovery, then add
> + * scope >= IPV6_ADDR_SCOPE_LINKLOCAL, too */
> + if (IPV6_ADDR_MC_SCOPE(&ip6hdr->daddr) !=
> + IPV6_ADDR_SCOPE_LINKLOCAL)
> + goto out;
> +
> + count = batadv_tt_global_hash_count(bat_priv, ethhdr->h_dest);
> +
> + if (!count)
> + ret = -1;
> + else if (count == 1)
> + ret = 0;
how can this function return more than one?
When there is more than one originator announcing the same MAC address then we
have _a single_ global entry having a list of orig_entry. but stil only one
global entry.
so you may want to count the orig_entries rather than the global_entries?
> diff --git a/translation-table.c b/translation-table.c
> index 37e7d47..1d2d618 100644
> --- a/translation-table.c
> +++ b/translation-table.c
> @@ -83,6 +83,40 @@ batadv_tt_hash_find(struct batadv_hashtable *hash, const
> void *data)
> return tt_common_entry_tmp;
> }
>
> +/**
> + * batadv_tt_hash_count - Counts the number of tt entries for the given data
> + * @hash: hash table containing the tt entries
> + * @data: The data to count entries for
One line saying what you are returning would be nice :)
> + */
> +static int batadv_tt_hash_count(struct batadv_hashtable *hash, const void
> *data)
> +{
> + struct hlist_head *head;
> + struct batadv_tt_common_entry *tt_common_entry;
> + uint32_t index;
> + int count = 0;
> +
> + if (!hash)
> + goto out;
> +
> + index = batadv_choose_orig(data, hash->size);
> + head = &hash->table[index];
> +
> + rcu_read_lock();
> + hlist_for_each_entry_rcu(tt_common_entry, head, hash_entry) {
> + if (!batadv_compare_eth(tt_common_entry, data))
> + continue;
> +
> + if (!atomic_read(&tt_common_entry->refcount))
> + continue;
> +
> + count++;
> + }
> + rcu_read_unlock();
> +
> +out:
> + return count;
> +}
as I asked before: this function cannot return >1 because the same address is
never stored twice.
Nice job so far!
Thanks for working on this cool feature!
Cheers,
--
Antonio Quartulli
..each of us alone is worth nothing..
Ernesto "Che" Guevara
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