Commit ab49886e authored by Linus Lüssing's avatar Linus Lüssing Committed by Antonio Quartulli
Browse files

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: default avatarLinus Lüssing <linus.luessing@web.de>
Signed-off-by: default avatarMarek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: default avatarAntonio Quartulli <antonio@meshcoding.com>
parent 1d8ab8d3

net/batman-adv/main.c

+6 −0
Original line number Diff line number Diff line
@@ -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);

net/batman-adv/main.h

+1 −0
Original line number Diff line number Diff line
@@ -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>

net/batman-adv/multicast.c

+127 −8
Original line number Diff line number Diff line
@@ -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);



	switch (tt_count) {

	total_count = tt_count + unsnoop_count;



	switch (total_count) {

	case 1:

		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);

}

net/batman-adv/packet.h

+9 −0
Original line number Diff line number Diff line
@@ -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

net/batman-adv/soft-interface.c

+1 −0
Original line number Diff line number Diff line
@@ -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);

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