[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
* ...and otherwise still gets flooded.
Signed-off-by: Linus Lüssing <linus.luessing@web.de>
---
multicast.c | 49 ++++++++++++++++++++++++++++++++++++++
multicast.h | 23 ++++++++++++++++++
soft-interface.c | 11 +++++++++
translation-table.c | 66 +++++++++++++++++++++++++++++++++++++++++++++++++++
translation-table.h | 1 +
5 files changed, 150 insertions(+)
@@ -21,6 +21,7 @@
#include "originator.h"
#include "hard-interface.h"
#include "translation-table.h"
+#include "multicast.h"
struct batadv_hw_addr {
struct list_head list;
@@ -209,6 +210,54 @@ out:
}
/**
+ * batadv_mcast_forw_mode - check on how to forward a multicast packet
+ * @skb: The multicast packet to check
+ * @bat_priv: the bat priv with all the soft interface information
+ *
+ * Return the forwarding mode as enum batadv_forw_mode.
+ */
+enum batadv_forw_mode
+batadv_mcast_forw_mode(struct sk_buff *skb, struct batadv_priv *bat_priv)
+{
+ struct ethhdr *ethhdr = (struct ethhdr *)(skb->data);
+ struct ipv6hdr *ip6hdr;
+ int count;
+
+ if (!atomic_read(&bat_priv->mcast_group_awareness))
+ return BATADV_FORW_ALL;
+
+ if (atomic_read(&bat_priv->mcast.num_no_mla))
+ return BATADV_FORW_ALL;
+
+ if (ntohs(ethhdr->h_proto) != ETH_P_IPV6)
+ return BATADV_FORW_ALL;
+
+ /* We might fail due to out-of-memory -> drop it */
+ if (!pskb_may_pull(skb, sizeof(*ethhdr) + sizeof(*ip6hdr)))
+ return BATADV_FORW_NONE;
+
+ 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)
+ return BATADV_FORW_ALL;
+
+ count = batadv_tt_global_hash_count(bat_priv, ethhdr->h_dest);
+
+ switch (count) {
+ case 0:
+ return BATADV_FORW_NONE;
+ case 1:
+ return BATADV_FORW_SINGLE;
+ default:
+ return BATADV_FORW_ALL;
+ }
+}
+
+/**
* 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
@@ -20,10 +20,27 @@
#ifndef _NET_BATMAN_ADV_MULTICAST_H_
#define _NET_BATMAN_ADV_MULTICAST_H_
+/**
+ * batadv_forw_mode - the way a packet should be forwarded as
+ * @BATADV_FORW_ALL: forward the packet to all nodes
+ * (currently via classic flooding)
+ * @BATADV_FORW_SINGLE: forward the packet to a single node
+ * (currently via the BATMAN_IV unicast routing protocol)
+ * @BATADV_FORW_NONE: don't forward, drop it
+ */
+enum batadv_forw_mode {
+ BATADV_FORW_ALL,
+ BATADV_FORW_SINGLE,
+ BATADV_FORW_NONE,
+};
+
#ifdef CONFIG_BATMAN_ADV_MCAST_OPTIMIZATIONS
void batadv_mcast_mla_tt_update(struct batadv_priv *bat_priv);
+enum batadv_forw_mode
+batadv_mcast_forw_mode(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);
@@ -37,6 +54,12 @@ static inline void batadv_mcast_mla_tt_update(struct batadv_priv *bat_priv)
return;
}
+static inline batadv_forw_mode
+batadv_mcast_forw_mode(struct sk_buff *skb, struct batadv_priv *bat_priv)
+{
+ return BATADV_FORW_ALL;
+}
+
static inline int batadv_mcast_init(struct batadv_priv *bat_priv)
{
return 0;
@@ -34,6 +34,7 @@
#include <linux/ethtool.h>
#include <linux/etherdevice.h>
#include <linux/if_vlan.h>
+#include "multicast.h"
#include "bridge_loop_avoidance.h"
#include "network-coding.h"
@@ -156,6 +157,7 @@ static int batadv_interface_tx(struct sk_buff *skb,
bool do_bcast = false;
uint32_t seqno;
unsigned long brd_delay = 1;
+ enum batadv_forw_mode mode;
if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
goto dropped;
@@ -218,6 +220,15 @@ static int batadv_interface_tx(struct sk_buff *skb,
default:
break;
}
+
+ if (do_bcast && !is_broadcast_ether_addr(ethhdr->h_dest)) {
+ mode = batadv_mcast_forw_mode(skb, bat_priv);
+ if (mode == BATADV_FORW_NONE)
+ goto dropped;
+
+ if (mode == BATADV_FORW_SINGLE)
+ do_bcast = false;
+ }
}
/* ethernet packet should be broadcasted */
@@ -83,6 +83,72 @@ batadv_tt_hash_find(struct batadv_hashtable *hash, const void *data)
return tt_common_entry_tmp;
}
+/**
+ * batadv_tt_orig_entries_count - count the number of originators
+ * @head: a list of originators
+ *
+ * Return the number of originator entries in the given list.
+ *
+ * The caller needs to hold the rcu_read_lock().
+ */
+static int batadv_tt_orig_entries_count(struct hlist_head *head)
+{
+ struct batadv_tt_orig_list_entry *orig_entry;
+ int count = 0;
+
+ hlist_for_each_entry_rcu(orig_entry, head, list) {
+ if (!atomic_read(&orig_entry->refcount))
+ continue;
+
+ count++;
+ }
+
+ return count;
+}
+
+/**
+ * batadv_tt_global_hash_count - count the number of orig entries
+ * @hash: hash table containing the tt entries
+ * @data: the data to count entries for
+ *
+ * Return the number of originators advertising the given address/data
+ * (excluding ourself).
+ */
+int batadv_tt_global_hash_count(struct batadv_priv *bat_priv, const void *data)
+{
+ struct hlist_head *head, *orig_list;
+ struct batadv_tt_common_entry *tt_common_entry;
+ struct batadv_tt_global_entry *tt_global_entry;
+ uint32_t index;
+ int count = 0;
+
+ if (!bat_priv->tt.global_hash)
+ goto out;
+
+ index = batadv_choose_orig(data, bat_priv->tt.global_hash->size);
+ head = &bat_priv->tt.global_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;
+
+ tt_global_entry = container_of(tt_common_entry,
+ struct batadv_tt_global_entry,
+ common);
+ orig_list = &tt_global_entry->orig_list;
+ count = batadv_tt_orig_entries_count(orig_list);
+ break;
+ }
+ 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)
{
@@ -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);