batman-adv: Add IPv4 link-local/IPv6-ll-all-nodes multicast support

With this patch a node may additionally perform the dropping or
unicasting behaviour for a link-local IPv4 and link-local-all-nodes
IPv6 multicast packet, too.

The extra counter and BATADV_MCAST_WANT_ALL_UNSNOOPABLES flag is needed
because with a future bridge snooping support integration a node with a
bridge on top of its soft interface is not able to reliably detect its
multicast listeners for IPv4 link-local and the IPv6
link-local-all-nodes addresses anymore (see RFC4541, section 2.1.2.2
and section 3).

Even though this new flag does make "no difference" now, it'll ensure
a seamless integration of multicast bridge support without needing to
break compatibility later.

Also note, that even with multicast bridge support it won't be possible
to optimize 224.0.0.x and ff02::1 towards nodes with bridges, they will
always receive these ranges.

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>

diff --git a/net/batman-adv/main.c b/net/batman-adv/main.c
index 8f11b67bc4f43f8aaa5593e7609dc1ce96b39bc6..57b09fa54b14fee703ab205dd7e12ac2a4b11723 100644 (file)
--- a/net/batman-adv/main.c
+++ b/net/batman-adv/main.c
@@ -111,6 +111,9 @@ int batadv_mesh_init(struct net_device *soft_iface)
        spin_lock_init(&bat_priv->tt.last_changeset_lock);
        spin_lock_init(&bat_priv->tt.commit_lock);
        spin_lock_init(&bat_priv->gw.list_lock);
+#ifdef CONFIG_BATMAN_ADV_MCAST
+       spin_lock_init(&bat_priv->mcast.want_lists_lock);
+#endif
        spin_lock_init(&bat_priv->tvlv.container_list_lock);
        spin_lock_init(&bat_priv->tvlv.handler_list_lock);
        spin_lock_init(&bat_priv->softif_vlan_list_lock);
@@ -118,6 +121,9 @@ int batadv_mesh_init(struct net_device *soft_iface)
        INIT_HLIST_HEAD(&bat_priv->forw_bat_list);
        INIT_HLIST_HEAD(&bat_priv->forw_bcast_list);
        INIT_HLIST_HEAD(&bat_priv->gw.list);
+#ifdef CONFIG_BATMAN_ADV_MCAST
+       INIT_HLIST_HEAD(&bat_priv->mcast.want_all_unsnoopables_list);
+#endif
        INIT_LIST_HEAD(&bat_priv->tt.changes_list);
        INIT_LIST_HEAD(&bat_priv->tt.req_list);
        INIT_LIST_HEAD(&bat_priv->tt.roam_list);

diff --git a/net/batman-adv/main.h b/net/batman-adv/main.h
index aa4f73a044c58c8b1099dfd895a9f07489b26970..515dce752fd2a8ec137556f92c6179a55035e889 100644 (file)
--- a/net/batman-adv/main.h
+++ b/net/batman-adv/main.h
@@ -177,6 +177,7 @@ enum batadv_uev_type {
 #include <linux/slab.h>
 #include <net/sock.h>          /* struct sock */
 #include <net/addrconf.h>      /* ipv6 address stuff */
+#include <linux/ip.h>
 #include <net/rtnetlink.h>
 #include <linux/jiffies.h>
 #include <linux/seq_file.h>

diff --git a/net/batman-adv/multicast.c b/net/batman-adv/multicast.c
index 1d1627fe0de013c1c80340d101b0c3b5b22b08d5..a4804fa1ad11c3d925b166fb7d0b9c6730662e1f 100644 (file)
--- a/net/batman-adv/multicast.c
+++ b/net/batman-adv/multicast.c
@@ -247,10 +247,49 @@ out:
        batadv_mcast_mla_list_free(&mcast_list);
 }
 
+/**
+ * batadv_mcast_forw_mode_check_ipv4 - check for optimized forwarding potential
+ * @bat_priv: the bat priv with all the soft interface information
+ * @skb: the IPv4 packet to check
+ * @is_unsnoopable: stores whether the destination is snoopable
+ *
+ * Checks whether the given IPv4 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 in case of
+ * memory allocation failure.
+ */
+static int batadv_mcast_forw_mode_check_ipv4(struct batadv_priv *bat_priv,
+                                            struct sk_buff *skb,
+                                            bool *is_unsnoopable)
+{
+       struct iphdr *iphdr;
+
+       /* We might fail due to out-of-memory -> drop it */
+       if (!pskb_may_pull(skb, sizeof(struct ethhdr) + sizeof(*iphdr)))
+               return -ENOMEM;
+
+       iphdr = ip_hdr(skb);
+
+       /* TODO: Implement Multicast Router Discovery (RFC4286),
+        * then allow scope > link local, too
+        */
+       if (!ipv4_is_local_multicast(iphdr->daddr))
+               return -EINVAL;
+
+       /* link-local multicast listeners behind a bridge are
+        * not snoopable (see RFC4541, section 2.1.2.2)
+        */
+       *is_unsnoopable = true;
+
+       return 0;
+}
+
 /**
  * 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
+ * @is_unsnoopable: stores whether the destination is snoopable
  *
  * Checks whether the given IPv6 packet has the potential to be forwarded with a
  * mode more optimal than classic flooding.
@@ -259,7 +298,8 @@ out:
  * of memory.
  */
 static int batadv_mcast_forw_mode_check_ipv6(struct batadv_priv *bat_priv,
-                                            struct sk_buff *skb)
+                                            struct sk_buff *skb,
+                                            bool *is_unsnoopable)
 {
        struct ipv6hdr *ip6hdr;
 
@@ -279,7 +319,7 @@ static int batadv_mcast_forw_mode_check_ipv6(struct batadv_priv *bat_priv,
         * not snoopable (see RFC4541, section 3, paragraph 3)
         */
        if (ipv6_addr_is_ll_all_nodes(&ip6hdr->daddr))
-               return -EINVAL;
+               *is_unsnoopable = true;
 
        return 0;
 }
@@ -288,6 +328,7 @@ static int batadv_mcast_forw_mode_check_ipv6(struct batadv_priv *bat_priv,
  * 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
+ * @is_unsnoopable: stores whether the destination is snoopable
  *
  * Checks whether the given multicast ethernet frame has the potential to be
  * forwarded with a mode more optimal than classic flooding.
@@ -296,7 +337,8 @@ static int batadv_mcast_forw_mode_check_ipv6(struct batadv_priv *bat_priv,
  * of memory.
  */
 static int batadv_mcast_forw_mode_check(struct batadv_priv *bat_priv,
-                                       struct sk_buff *skb)
+                                       struct sk_buff *skb,
+                                       bool *is_unsnoopable)
 {
        struct ethhdr *ethhdr = eth_hdr(skb);
 
@@ -307,8 +349,12 @@ static int batadv_mcast_forw_mode_check(struct batadv_priv *bat_priv,
                return -EINVAL;
 
        switch (ntohs(ethhdr->h_proto)) {
+       case ETH_P_IP:
+               return batadv_mcast_forw_mode_check_ipv4(bat_priv, skb,
+                                                        is_unsnoopable);
        case ETH_P_IPV6:
-               return batadv_mcast_forw_mode_check_ipv6(bat_priv, skb);
+               return batadv_mcast_forw_mode_check_ipv6(bat_priv, skb,
+                                                        is_unsnoopable);
        default:
                return -EINVAL;
        }
@@ -330,6 +376,33 @@ batadv_mcast_forw_tt_node_get(struct batadv_priv *bat_priv,
                                        ethhdr->h_dest, BATADV_NO_FLAGS);
 }
 
+/**
+ * batadv_mcast_want_forw_unsnoop_node_get - get a node with an unsnoopable flag
+ * @bat_priv: the bat priv with all the soft interface information
+ *
+ * Returns an orig_node which has the BATADV_MCAST_WANT_ALL_UNSNOOPABLES flag
+ * set and increases its refcount.
+ */
+static struct batadv_orig_node *
+batadv_mcast_forw_unsnoop_node_get(struct batadv_priv *bat_priv)
+{
+       struct batadv_orig_node *tmp_orig_node, *orig_node = NULL;
+
+       rcu_read_lock();
+       hlist_for_each_entry_rcu(tmp_orig_node,
+                                &bat_priv->mcast.want_all_unsnoopables_list,
+                                mcast_want_all_unsnoopables_node) {
+               if (!atomic_inc_not_zero(&orig_node->refcount))
+                       continue;
+
+               orig_node = tmp_orig_node;
+               break;
+       }
+       rcu_read_unlock();
+
+       return orig_node;
+}
+
 /**
  * batadv_mcast_forw_mode - check on how to forward a multicast packet
  * @bat_priv: the bat priv with all the soft interface information
@@ -344,10 +417,11 @@ enum batadv_forw_mode
 batadv_mcast_forw_mode(struct batadv_priv *bat_priv, struct sk_buff *skb,
                       struct batadv_orig_node **orig)
 {
+       int ret, tt_count, unsnoop_count, total_count;
+       bool is_unsnoopable = false;
        struct ethhdr *ethhdr;
-       int ret, tt_count;
 
-       ret = batadv_mcast_forw_mode_check(bat_priv, skb);
+       ret = batadv_mcast_forw_mode_check(bat_priv, skb, &is_unsnoopable);
        if (ret == -ENOMEM)
                return BATADV_FORW_NONE;
        else if (ret < 0)
@@ -357,10 +431,18 @@ batadv_mcast_forw_mode(struct batadv_priv *bat_priv, struct sk_buff *skb,
 
        tt_count = batadv_tt_global_hash_count(bat_priv, ethhdr->h_dest,
                                               BATADV_NO_FLAGS);
+       unsnoop_count = !is_unsnoopable ? 0 :
+                       atomic_read(&bat_priv->mcast.num_want_all_unsnoopables);
+
+       total_count = tt_count + unsnoop_count;
 
-       switch (tt_count) {
+       switch (total_count) {
        case 1:
-               *orig = batadv_mcast_forw_tt_node_get(bat_priv, ethhdr);
+               if (tt_count)
+                       *orig = batadv_mcast_forw_tt_node_get(bat_priv, ethhdr);
+               else if (unsnoop_count)
+                       *orig = batadv_mcast_forw_unsnoop_node_get(bat_priv);
+
                if (*orig)
                        return BATADV_FORW_SINGLE;
 
@@ -372,6 +454,39 @@ batadv_mcast_forw_mode(struct batadv_priv *bat_priv, struct sk_buff *skb,
        }
 }
 
+/**
+ * batadv_mcast_want_unsnoop_update - update unsnoop counter and list
+ * @bat_priv: the bat priv with all the soft interface information
+ * @orig: the orig_node which multicast state might have changed of
+ * @mcast_flags: flags indicating the new multicast state
+ *
+ * If the BATADV_MCAST_WANT_ALL_UNSNOOPABLES flag of this originator,
+ * orig, has toggled then this method updates counter and list accordingly.
+ */
+static void batadv_mcast_want_unsnoop_update(struct batadv_priv *bat_priv,
+                                            struct batadv_orig_node *orig,
+                                            uint8_t mcast_flags)
+{
+       /* switched from flag unset to set */
+       if (mcast_flags & BATADV_MCAST_WANT_ALL_UNSNOOPABLES &&
+           !(orig->mcast_flags & BATADV_MCAST_WANT_ALL_UNSNOOPABLES)) {
+               atomic_inc(&bat_priv->mcast.num_want_all_unsnoopables);
+
+               spin_lock_bh(&bat_priv->mcast.want_lists_lock);
+               hlist_add_head_rcu(&orig->mcast_want_all_unsnoopables_node,
+                                  &bat_priv->mcast.want_all_unsnoopables_list);
+               spin_unlock_bh(&bat_priv->mcast.want_lists_lock);
+       /* switched from flag set to unset */
+       } else if (!(mcast_flags & BATADV_MCAST_WANT_ALL_UNSNOOPABLES) &&
+                  orig->mcast_flags & BATADV_MCAST_WANT_ALL_UNSNOOPABLES) {
+               atomic_dec(&bat_priv->mcast.num_want_all_unsnoopables);
+
+               spin_lock_bh(&bat_priv->mcast.want_lists_lock);
+               hlist_del_rcu(&orig->mcast_want_all_unsnoopables_node);
+               spin_unlock_bh(&bat_priv->mcast.want_lists_lock);
+       }
+}
+
 /**
  * batadv_mcast_tvlv_ogm_handler_v1 - process incoming multicast tvlv container
  * @bat_priv: the bat priv with all the soft interface information
@@ -416,6 +531,8 @@ static void batadv_mcast_tvlv_ogm_handler_v1(struct batadv_priv *bat_priv,
            (tvlv_value_len >= sizeof(mcast_flags)))
                mcast_flags = *(uint8_t *)tvlv_value;
 
+       batadv_mcast_want_unsnoop_update(bat_priv, orig, mcast_flags);
+
        orig->mcast_flags = mcast_flags;
 }
 
@@ -452,4 +569,6 @@ void batadv_mcast_purge_orig(struct batadv_orig_node *orig)
 
        if (!(orig->capabilities & BATADV_ORIG_CAPA_HAS_MCAST))
                atomic_dec(&bat_priv->mcast.num_disabled);
+
+       batadv_mcast_want_unsnoop_update(bat_priv, orig, BATADV_NO_FLAGS);
 }

diff --git a/net/batman-adv/packet.h b/net/batman-adv/packet.h
index e8c483d2da72855ce33e8390df20c9831b36ce85..d061e26c20457e89da5ea5710b11fdc1657bce31 100644 (file)
--- a/net/batman-adv/packet.h
+++ b/net/batman-adv/packet.h
@@ -89,6 +89,15 @@ enum batadv_icmp_packettype {
        BATADV_PARAMETER_PROBLEM       = 12,
 };
 
+/**
+ * enum batadv_mcast_flags - flags for multicast capabilities and settings
+ * @BATADV_MCAST_WANT_ALL_UNSNOOPABLES: we want all packets destined for
+ *  224.0.0.0/24 or ff02::1
+ */
+enum batadv_mcast_flags {
+       BATADV_MCAST_WANT_ALL_UNSNOOPABLES      = BIT(0),
+};
+
 /* tt data subtypes */
 #define BATADV_TT_DATA_TYPE_MASK 0x0F
 

diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c
index 1a643fe647e18b9332c20d98834fae9ed0c23682..db6fecaddb9cd2046c0d3757c211d2f40fd643ff 100644 (file)
--- a/net/batman-adv/soft-interface.c
+++ b/net/batman-adv/soft-interface.c
@@ -710,6 +710,7 @@ static int batadv_softif_init_late(struct net_device *dev)
        bat_priv->mcast.flags = BATADV_NO_FLAGS;
        atomic_set(&bat_priv->multicast_mode, 1);
        atomic_set(&bat_priv->mcast.num_disabled, 0);
+       atomic_set(&bat_priv->mcast.num_want_all_unsnoopables, 0);
 #endif
        atomic_set(&bat_priv->gw_mode, BATADV_GW_MODE_OFF);
        atomic_set(&bat_priv->gw_sel_class, 20);

diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h
index c28fc4a403a382ee63a99803e2495d69429852e6..1a674cb195531fc68bf156201c9a7019df658be3 100644 (file)
--- a/net/batman-adv/types.h
+++ b/net/batman-adv/types.h
@@ -205,6 +205,8 @@ struct batadv_orig_bat_iv {
  * @last_seen: time when last packet from this node was received
  * @bcast_seqno_reset: time when the broadcast seqno window was reset
  * @mcast_flags: multicast flags announced by the orig node
+ * @mcast_want_all_unsnoop_node: a list node for the
+ *  mcast.want_all_unsnoopables list
  * @capabilities: announced capabilities of this originator
  * @capa_initialized: bitfield to remember whether a capability was initialized
  * @last_ttvn: last seen translation table version number
@@ -249,6 +251,7 @@ struct batadv_orig_node {
        unsigned long bcast_seqno_reset;
 #ifdef CONFIG_BATMAN_ADV_MCAST
        uint8_t mcast_flags;
+       struct hlist_node mcast_want_all_unsnoopables_node;
 #endif
        uint8_t capabilities;
        uint8_t capa_initialized;
@@ -619,15 +622,24 @@ struct batadv_priv_dat {
 /**
  * struct batadv_priv_mcast - per mesh interface mcast data
  * @mla_list: list of multicast addresses we are currently announcing via TT
+ * @want_all_unsnoopables_list: a list of orig_nodes wanting all unsnoopable
+ *  multicast traffic
  * @flags: the flags we have last sent in our mcast tvlv
  * @enabled: whether the multicast tvlv is currently enabled
  * @num_disabled: number of nodes that have no mcast tvlv
+ * @num_want_all_unsnoopables: number of nodes wanting unsnoopable IP traffic
+ * @want_lists_lock: lock for protecting modifications to mcast want lists
+ *  (traversals are rcu-locked)
  */
 struct batadv_priv_mcast {
        struct hlist_head mla_list;
+       struct hlist_head want_all_unsnoopables_list;
        uint8_t flags;
        bool enabled;
        atomic_t num_disabled;
+       atomic_t num_want_all_unsnoopables;
+       /* protects want_all_unsnoopables_list */
+       spinlock_t want_lists_lock;
 };
 #endif