[3/3] batman-adv: Modified forwarding behaviour for multicast packets
Commit Message
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.
Signed-off-by: Linus Lüssing <linus.luessing@web.de>
---
multicast.c | 42 ++++++++++++++++++++++++++++++++++++++++++
multicast.h | 8 ++++++++
soft-interface.c | 10 ++++++++++
translation-table.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
translation-table.h | 1 +
5 files changed, 105 insertions(+)
Comments
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,
On Sun, May 12, 2013 at 01:29:29AM +0200, Antonio Quartulli wrote:
> 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?
Yes, it will get flooded. Thought it was clear because I was
saying "for the following cases is changed", trying to imply that
for anything else it'll still get flooded. But ok, I can make it
more explicit.
>
> >
> > /**
> > + * 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? :)
I guess I overlooked, will try to add that in the same patch, too.
>
> > + 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?
You are right, looks like I only tested dropping vs. unicast, not
unicast vs. flooding behaviour in my VMs.
>
> > 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 :)
ok
>
> > + */
> > +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
Cheers, Linus
On Thu, May 16, 2013 at 08:22:25PM +0200, Linus Lüssing wrote:
> On Sun, May 12, 2013 at 01:29:29AM +0200, Antonio Quartulli wrote:
> > 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?
>
> Yes, it will get flooded. Thought it was clear because I was
> saying "for the following cases is changed", trying to imply that
> for anything else it'll still get flooded. But ok, I can make it
> more explicit.
Yes, please
Cheers,
@@ -218,6 +218,48 @@ out:
}
/**
+ * 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) {
+ 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;
+ }
+
+out:
+ return ret;
+}
+
+/**
* batadv_mcast_tvlv_ogm_handler_v1 - process incoming multicast tvlv container
* @bat_priv: the bat priv with all the soft interface information
* @orig: the orig_node of the ogm
@@ -24,6 +24,8 @@
void batadv_mcast_mla_tt_update(struct batadv_priv *bat_priv);
+int batadv_mcast_flood(struct sk_buff *skb, struct batadv_priv *bat_priv);
+
int batadv_mcast_init(struct batadv_priv *bat_priv);
void batadv_mcast_free(struct batadv_priv *bat_priv);
@@ -35,6 +37,12 @@ static inline void batadv_mcast_mla_tt_update(struct batadv_priv *bat_priv)
return;
}
+static inline int batadv_mcast_flood(struct sk_buff *skb,
+ struct batadv_priv *bat_priv)
+{
+ return 1;
+}
+
static inline int batadv_mcast_init(struct batadv_priv *bat_priv)
{
return 0;
@@ -36,6 +36,7 @@
#include <linux/if_vlan.h>
#include <linux/if_ether.h>
#include "unicast.h"
+#include "multicast.h"
#include "bridge_loop_avoidance.h"
#include "network-coding.h"
@@ -222,6 +223,15 @@ static int batadv_interface_tx(struct sk_buff *skb,
}
}
+ if (do_bcast && !is_broadcast_ether_addr(ethhdr->h_dest)) {
+ ret = batadv_mcast_flood(skb, bat_priv);
+ if (ret < 0)
+ goto dropped;
+
+ if (!ret)
+ do_bcast = false;
+ }
+
/* ethernet packet should be broadcasted */
if (do_bcast) {
primary_if = batadv_primary_if_get_selected(bat_priv);
@@ -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
+ */
+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;
+}
+
static struct batadv_tt_local_entry *
batadv_tt_local_hash_find(struct batadv_priv *bat_priv, const void *data)
{
@@ -111,6 +145,16 @@ batadv_tt_global_hash_find(struct batadv_priv *bat_priv, const void *data)
return tt_global_entry;
}
+/**
+ * batadv_tt_hash_count - Counts the number of global tt entries for some data
+ * @bat_priv: the bat priv with all the soft interface information
+ * @data: The data to count entries for
+ */
+int batadv_tt_global_hash_count(struct batadv_priv *bat_priv, const void *data)
+{
+ return batadv_tt_hash_count(bat_priv->tt.global_hash, data);
+}
+
static void
batadv_tt_local_entry_free_ref(struct batadv_tt_local_entry *tt_local_entry)
{
@@ -31,6 +31,7 @@ int batadv_tt_global_seq_print_text(struct seq_file *seq, void *offset);
void batadv_tt_global_del_orig(struct batadv_priv *bat_priv,
struct batadv_orig_node *orig_node,
const char *message);
+int batadv_tt_global_hash_count(struct batadv_priv *bat_priv, const void *data);
struct batadv_orig_node *batadv_transtable_search(struct batadv_priv *bat_priv,
const uint8_t *src,
const uint8_t *addr);