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