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authorLinus Lüssing <linus.luessing@web.de>2014-02-15 17:47:52 +0100
committerAntonio Quartulli <antonio@meshcoding.com>2014-03-22 09:18:57 +0100
commit1d8ab8d3c176d31530b3ffd4547cf731018e2a45 (patch)
treeb62208972cdfb70a853ff5177c29154fd165bea7 /net/batman-adv/multicast.c
parent60432d756cf06e597ef9da511402dd059b112447 (diff)
batman-adv: Modified forwarding behaviour for multicast packets
With this patch a multicast packet is not always simply flooded anymore, the behaviour 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 then an IPv6 multicast packet with a destination of IPv6 link-local scope (excluding ff02::1) 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> Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch> Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>
Diffstat (limited to 'net/batman-adv/multicast.c')
-rw-r--r--net/batman-adv/multicast.c126
1 files changed, 126 insertions, 0 deletions
diff --git a/net/batman-adv/multicast.c b/net/batman-adv/multicast.c
index 3ba9a18a906c..1d1627fe0de0 100644
--- a/net/batman-adv/multicast.c
+++ b/net/batman-adv/multicast.c
@@ -20,6 +20,7 @@
#include "originator.h"
#include "hard-interface.h"
#include "translation-table.h"
+#include "multicast.h"
/**
* batadv_mcast_mla_softif_get - get softif multicast listeners
@@ -247,6 +248,131 @@ out:
}
/**
+ * batadv_mcast_forw_mode_check_ipv6 - check for optimized forwarding potential
+ * @bat_priv: the bat priv with all the soft interface information
+ * @skb: the IPv6 packet to check
+ *
+ * Checks whether the given IPv6 packet has the potential to be forwarded with a
+ * mode more optimal than classic flooding.
+ *
+ * If so then returns 0. Otherwise -EINVAL is returned or -ENOMEM if we are out
+ * of memory.
+ */
+static int batadv_mcast_forw_mode_check_ipv6(struct batadv_priv *bat_priv,
+ struct sk_buff *skb)
+{
+ struct ipv6hdr *ip6hdr;
+
+ /* We might fail due to out-of-memory -> drop it */
+ if (!pskb_may_pull(skb, sizeof(struct ethhdr) + sizeof(*ip6hdr)))
+ return -ENOMEM;
+
+ ip6hdr = ipv6_hdr(skb);
+
+ /* TODO: Implement Multicast Router Discovery (RFC4286),
+ * then allow scope > link local, too
+ */
+ if (IPV6_ADDR_MC_SCOPE(&ip6hdr->daddr) != IPV6_ADDR_SCOPE_LINKLOCAL)
+ return -EINVAL;
+
+ /* link-local-all-nodes multicast listeners behind a bridge are
+ * not snoopable (see RFC4541, section 3, paragraph 3)
+ */
+ if (ipv6_addr_is_ll_all_nodes(&ip6hdr->daddr))
+ return -EINVAL;
+
+ return 0;
+}
+
+/**
+ * batadv_mcast_forw_mode_check - check for optimized forwarding potential
+ * @bat_priv: the bat priv with all the soft interface information
+ * @skb: the multicast frame to check
+ *
+ * Checks whether the given multicast ethernet frame has the potential to be
+ * forwarded with a mode more optimal than classic flooding.
+ *
+ * If so then returns 0. Otherwise -EINVAL is returned or -ENOMEM if we are out
+ * of memory.
+ */
+static int batadv_mcast_forw_mode_check(struct batadv_priv *bat_priv,
+ struct sk_buff *skb)
+{
+ struct ethhdr *ethhdr = eth_hdr(skb);
+
+ if (!atomic_read(&bat_priv->multicast_mode))
+ return -EINVAL;
+
+ if (atomic_read(&bat_priv->mcast.num_disabled))
+ return -EINVAL;
+
+ switch (ntohs(ethhdr->h_proto)) {
+ case ETH_P_IPV6:
+ return batadv_mcast_forw_mode_check_ipv6(bat_priv, skb);
+ default:
+ return -EINVAL;
+ }
+}
+
+/**
+ * batadv_mcast_forw_tt_node_get - get a multicast tt node
+ * @bat_priv: the bat priv with all the soft interface information
+ * @ethhdr: the ether header containing the multicast destination
+ *
+ * Returns an orig_node matching the multicast address provided by ethhdr
+ * via a translation table lookup. This increases the returned nodes refcount.
+ */
+static struct batadv_orig_node *
+batadv_mcast_forw_tt_node_get(struct batadv_priv *bat_priv,
+ struct ethhdr *ethhdr)
+{
+ return batadv_transtable_search(bat_priv, ethhdr->h_source,
+ ethhdr->h_dest, BATADV_NO_FLAGS);
+}
+
+/**
+ * batadv_mcast_forw_mode - check on how to forward a multicast packet
+ * @bat_priv: the bat priv with all the soft interface information
+ * @skb: The multicast packet to check
+ * @orig: an originator to be set to forward the skb to
+ *
+ * Returns the forwarding mode as enum batadv_forw_mode and in case of
+ * BATADV_FORW_SINGLE set the orig to the single originator the skb
+ * should be forwarded to.
+ */
+enum batadv_forw_mode
+batadv_mcast_forw_mode(struct batadv_priv *bat_priv, struct sk_buff *skb,
+ struct batadv_orig_node **orig)
+{
+ struct ethhdr *ethhdr;
+ int ret, tt_count;
+
+ ret = batadv_mcast_forw_mode_check(bat_priv, skb);
+ if (ret == -ENOMEM)
+ return BATADV_FORW_NONE;
+ else if (ret < 0)
+ return BATADV_FORW_ALL;
+
+ ethhdr = eth_hdr(skb);
+
+ tt_count = batadv_tt_global_hash_count(bat_priv, ethhdr->h_dest,
+ BATADV_NO_FLAGS);
+
+ switch (tt_count) {
+ case 1:
+ *orig = batadv_mcast_forw_tt_node_get(bat_priv, ethhdr);
+ if (*orig)
+ return BATADV_FORW_SINGLE;
+
+ /* fall through */
+ case 0:
+ return BATADV_FORW_NONE;
+ 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