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Commit 11d458c1 authored by Linus Lüssing's avatar Linus Lüssing Committed by Simon Wunderlich
Browse files

batman-adv: mcast: apply optimizations for routable packets, too 



Now that we not only track the presence of multicast listeners but also
multicast routers we can safely apply group-aware multicast-to-unicast
forwarding to packets with a destination address of scope greater than
link-local as well.

Signed-off-by: default avatarLinus Lüssing <linus.luessing@c0d3.blue>
Signed-off-by: default avatarSven Eckelmann <sven@narfation.org>
Signed-off-by: default avatarSimon Wunderlich <sw@simonwunderlich.de>
parent 61caf3d1

net/batman-adv/multicast.c

+241 −18
Original line number Diff line number Diff line
@@ -980,6 +980,7 @@ static bool batadv_mcast_is_report_ipv4(struct sk_buff *skb) 
 * @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

 * @is_routable: stores whether the destination is routable

 *

 * Checks whether the given IPv4 packet has the potential to be forwarded with a

 * mode more optimal than classic flooding.
@@ -989,7 +990,8 @@ static bool batadv_mcast_is_report_ipv4(struct sk_buff *skb) 
 */

static int batadv_mcast_forw_mode_check_ipv4(struct batadv_priv *bat_priv,

					     struct sk_buff *skb,

					     bool *is_unsnoopable)

					     bool *is_unsnoopable,

					     int *is_routable)

{

	struct iphdr *iphdr;
@@ -1002,16 +1004,13 @@ static int batadv_mcast_forw_mode_check_ipv4(struct batadv_priv *bat_priv, 


	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)

	 */

	if (ipv4_is_local_multicast(iphdr->daddr))

		*is_unsnoopable = true;

	else

		*is_routable = ETH_P_IP;



	return 0;

}
@@ -1046,6 +1045,7 @@ static bool batadv_mcast_is_report_ipv6(struct sk_buff *skb) 
 * @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

 * @is_routable: stores whether the destination is routable

 *

 * Checks whether the given IPv6 packet has the potential to be forwarded with a

 * mode more optimal than classic flooding.
@@ -1054,7 +1054,8 @@ static bool batadv_mcast_is_report_ipv6(struct sk_buff *skb) 
 */

static int batadv_mcast_forw_mode_check_ipv6(struct batadv_priv *bat_priv,

					     struct sk_buff *skb,

					     bool *is_unsnoopable)

					     bool *is_unsnoopable,

					     int *is_routable)

{

	struct ipv6hdr *ip6hdr;
@@ -1067,10 +1068,7 @@ static int batadv_mcast_forw_mode_check_ipv6(struct batadv_priv *bat_priv, 


	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)

	if (IPV6_ADDR_MC_SCOPE(&ip6hdr->daddr) < IPV6_ADDR_SCOPE_LINKLOCAL)

		return -EINVAL;



	/* link-local-all-nodes multicast listeners behind a bridge are
@@ -1078,6 +1076,8 @@ static int batadv_mcast_forw_mode_check_ipv6(struct batadv_priv *bat_priv, 
	 */

	if (ipv6_addr_is_ll_all_nodes(&ip6hdr->daddr))

		*is_unsnoopable = true;

	else if (IPV6_ADDR_MC_SCOPE(&ip6hdr->daddr) > IPV6_ADDR_SCOPE_LINKLOCAL)

		*is_routable = ETH_P_IPV6;



	return 0;

}
@@ -1087,6 +1087,7 @@ static int batadv_mcast_forw_mode_check_ipv6(struct batadv_priv *bat_priv, 
 * @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

 * @is_routable: stores whether the destination is routable

 *

 * Checks whether the given multicast ethernet frame has the potential to be

 * forwarded with a mode more optimal than classic flooding.
@@ -1095,7 +1096,8 @@ static int batadv_mcast_forw_mode_check_ipv6(struct batadv_priv *bat_priv, 
 */

static int batadv_mcast_forw_mode_check(struct batadv_priv *bat_priv,

					struct sk_buff *skb,

					bool *is_unsnoopable)

					bool *is_unsnoopable,

					int *is_routable)

{

	struct ethhdr *ethhdr = eth_hdr(skb);
@@ -1105,13 +1107,15 @@ static int batadv_mcast_forw_mode_check(struct batadv_priv *bat_priv, 
	switch (ntohs(ethhdr->h_proto)) {

	case ETH_P_IP:

		return batadv_mcast_forw_mode_check_ipv4(bat_priv, skb,

							 is_unsnoopable);

							 is_unsnoopable,

							 is_routable);

	case ETH_P_IPV6:

		if (!IS_ENABLED(CONFIG_IPV6))

			return -EINVAL;



		return batadv_mcast_forw_mode_check_ipv6(bat_priv, skb,

							 is_unsnoopable);

							 is_unsnoopable,

							 is_routable);

	default:

		return -EINVAL;

	}
@@ -1141,6 +1145,29 @@ static int batadv_mcast_forw_want_all_ip_count(struct batadv_priv *bat_priv, 
	}

}



/**

 * batadv_mcast_forw_rtr_count() - count nodes with a multicast router

 * @bat_priv: the bat priv with all the soft interface information

 * @protocol: the ethernet protocol type to count multicast routers for

 *

 * Return: the number of nodes which want all routable IPv4 multicast traffic

 * if the protocol is ETH_P_IP or the number of nodes which want all routable

 * IPv6 traffic if the protocol is ETH_P_IPV6. Otherwise returns 0.

 */



static int batadv_mcast_forw_rtr_count(struct batadv_priv *bat_priv,

				       int protocol)

{

	switch (protocol) {

	case ETH_P_IP:

		return atomic_read(&bat_priv->mcast.num_want_all_rtr4);

	case ETH_P_IPV6:

		return atomic_read(&bat_priv->mcast.num_want_all_rtr6);

	default:

		return 0;

	}

}



/**

 * batadv_mcast_forw_tt_node_get() - get a multicast tt node

 * @bat_priv: the bat priv with all the soft interface information
@@ -1262,6 +1289,84 @@ batadv_mcast_forw_unsnoop_node_get(struct batadv_priv *bat_priv) 
	return orig_node;

}



/**

 * batadv_mcast_forw_rtr4_node_get() - get a node with an ipv4 mcast router flag

 * @bat_priv: the bat priv with all the soft interface information

 *

 * Return: an orig_node which has the BATADV_MCAST_WANT_NO_RTR4 flag unset and

 * increases its refcount.

 */

static struct batadv_orig_node *

batadv_mcast_forw_rtr4_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_rtr4_list,

				 mcast_want_all_rtr4_node) {

		if (!kref_get_unless_zero(&tmp_orig_node->refcount))

			continue;



		orig_node = tmp_orig_node;

		break;

	}

	rcu_read_unlock();



	return orig_node;

}



/**

 * batadv_mcast_forw_rtr6_node_get() - get a node with an ipv6 mcast router flag

 * @bat_priv: the bat priv with all the soft interface information

 *

 * Return: an orig_node which has the BATADV_MCAST_WANT_NO_RTR6 flag unset

 * and increases its refcount.

 */

static struct batadv_orig_node *

batadv_mcast_forw_rtr6_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_rtr6_list,

				 mcast_want_all_rtr6_node) {

		if (!kref_get_unless_zero(&tmp_orig_node->refcount))

			continue;



		orig_node = tmp_orig_node;

		break;

	}

	rcu_read_unlock();



	return orig_node;

}



/**

 * batadv_mcast_forw_rtr_node_get() - get a node with an ipv4/ipv6 router flag

 * @bat_priv: the bat priv with all the soft interface information

 * @ethhdr: an ethernet header to determine the protocol family from

 *

 * Return: an orig_node which has no BATADV_MCAST_WANT_NO_RTR4 or

 * BATADV_MCAST_WANT_NO_RTR6 flag, depending on the provided ethhdr, set and

 * increases its refcount.

 */

static struct batadv_orig_node *

batadv_mcast_forw_rtr_node_get(struct batadv_priv *bat_priv,

			       struct ethhdr *ethhdr)

{

	switch (ntohs(ethhdr->h_proto)) {

	case ETH_P_IP:

		return batadv_mcast_forw_rtr4_node_get(bat_priv);

	case ETH_P_IPV6:

		return batadv_mcast_forw_rtr6_node_get(bat_priv);

	default:

		/* we shouldn't be here... */

		return NULL;

	}

}



/**

 * batadv_mcast_forw_mode() - check on how to forward a multicast packet

 * @bat_priv: the bat priv with all the soft interface information
@@ -1280,8 +1385,11 @@ batadv_mcast_forw_mode(struct batadv_priv *bat_priv, struct sk_buff *skb, 
	bool is_unsnoopable = false;

	unsigned int mcast_fanout;

	struct ethhdr *ethhdr;

	int is_routable = 0;

	int rtr_count = 0;



	ret = batadv_mcast_forw_mode_check(bat_priv, skb, &is_unsnoopable);

	ret = batadv_mcast_forw_mode_check(bat_priv, skb, &is_unsnoopable,

					   &is_routable);

	if (ret == -ENOMEM)

		return BATADV_FORW_NONE;

	else if (ret < 0)
@@ -1294,8 +1402,9 @@ batadv_mcast_forw_mode(struct batadv_priv *bat_priv, struct sk_buff *skb, 
	ip_count = batadv_mcast_forw_want_all_ip_count(bat_priv, ethhdr);

	unsnoop_count = !is_unsnoopable ? 0 :

			atomic_read(&bat_priv->mcast.num_want_all_unsnoopables);

	rtr_count = batadv_mcast_forw_rtr_count(bat_priv, is_routable);



	total_count = tt_count + ip_count + unsnoop_count;

	total_count = tt_count + ip_count + unsnoop_count + rtr_count;



	switch (total_count) {

	case 1:
@@ -1305,6 +1414,9 @@ batadv_mcast_forw_mode(struct batadv_priv *bat_priv, struct sk_buff *skb, 
			*orig = batadv_mcast_forw_ip_node_get(bat_priv, ethhdr);

		else if (unsnoop_count)

			*orig = batadv_mcast_forw_unsnoop_node_get(bat_priv);

		else if (rtr_count)

			*orig = batadv_mcast_forw_rtr_node_get(bat_priv,

							       ethhdr);



		if (*orig)

			return BATADV_FORW_SINGLE;
@@ -1475,6 +1587,111 @@ batadv_mcast_forw_want_all(struct batadv_priv *bat_priv, 
	}

}



/**

 * batadv_mcast_forw_want_all_rtr4() - forward to nodes with want-all-rtr4

 * @bat_priv: the bat priv with all the soft interface information

 * @skb: the multicast packet to transmit

 * @vid: the vlan identifier

 *

 * Sends copies of a frame with multicast destination to any node with a

 * BATADV_MCAST_WANT_NO_RTR4 flag unset. A transmission is performed via a

 * batman-adv unicast packet for each such destination node.

 *

 * Return: NET_XMIT_DROP on memory allocation failure, NET_XMIT_SUCCESS

 * otherwise.

 */

static int

batadv_mcast_forw_want_all_rtr4(struct batadv_priv *bat_priv,

				struct sk_buff *skb, unsigned short vid)

{

	struct batadv_orig_node *orig_node;

	int ret = NET_XMIT_SUCCESS;

	struct sk_buff *newskb;



	rcu_read_lock();

	hlist_for_each_entry_rcu(orig_node,

				 &bat_priv->mcast.want_all_rtr4_list,

				 mcast_want_all_rtr4_node) {

		newskb = skb_copy(skb, GFP_ATOMIC);

		if (!newskb) {

			ret = NET_XMIT_DROP;

			break;

		}



		batadv_send_skb_unicast(bat_priv, newskb, BATADV_UNICAST, 0,

					orig_node, vid);

	}

	rcu_read_unlock();

	return ret;

}



/**

 * batadv_mcast_forw_want_all_rtr6() - forward to nodes with want-all-rtr6

 * @bat_priv: the bat priv with all the soft interface information

 * @skb: The multicast packet to transmit

 * @vid: the vlan identifier

 *

 * Sends copies of a frame with multicast destination to any node with a

 * BATADV_MCAST_WANT_NO_RTR6 flag unset. A transmission is performed via a

 * batman-adv unicast packet for each such destination node.

 *

 * Return: NET_XMIT_DROP on memory allocation failure, NET_XMIT_SUCCESS

 * otherwise.

 */

static int

batadv_mcast_forw_want_all_rtr6(struct batadv_priv *bat_priv,

				struct sk_buff *skb, unsigned short vid)

{

	struct batadv_orig_node *orig_node;

	int ret = NET_XMIT_SUCCESS;

	struct sk_buff *newskb;



	rcu_read_lock();

	hlist_for_each_entry_rcu(orig_node,

				 &bat_priv->mcast.want_all_rtr6_list,

				 mcast_want_all_rtr6_node) {

		newskb = skb_copy(skb, GFP_ATOMIC);

		if (!newskb) {

			ret = NET_XMIT_DROP;

			break;

		}



		batadv_send_skb_unicast(bat_priv, newskb, BATADV_UNICAST, 0,

					orig_node, vid);

	}

	rcu_read_unlock();

	return ret;

}



/**

 * batadv_mcast_forw_want_rtr() - forward packet to nodes in a want-all-rtr list

 * @bat_priv: the bat priv with all the soft interface information

 * @skb: the multicast packet to transmit

 * @vid: the vlan identifier

 *

 * Sends copies of a frame with multicast destination to any node with a

 * BATADV_MCAST_WANT_NO_RTR4 or BATADV_MCAST_WANT_NO_RTR6 flag unset. A

 * transmission is performed via a batman-adv unicast packet for each such

 * destination node.

 *

 * Return: NET_XMIT_DROP on memory allocation failure or if the protocol family

 * is neither IPv4 nor IPv6. NET_XMIT_SUCCESS otherwise.

 */

static int

batadv_mcast_forw_want_rtr(struct batadv_priv *bat_priv,

			   struct sk_buff *skb, unsigned short vid)

{

	switch (ntohs(eth_hdr(skb)->h_proto)) {

	case ETH_P_IP:

		return batadv_mcast_forw_want_all_rtr4(bat_priv, skb, vid);

	case ETH_P_IPV6:

		return batadv_mcast_forw_want_all_rtr6(bat_priv, skb, vid);

	default:

		/* we shouldn't be here... */

		return NET_XMIT_DROP;

	}

}



/**

 * batadv_mcast_forw_send() - send packet to any detected multicast recpient

 * @bat_priv: the bat priv with all the soft interface information
@@ -1508,6 +1725,12 @@ int batadv_mcast_forw_send(struct batadv_priv *bat_priv, struct sk_buff *skb, 
		return ret;

	}



	ret = batadv_mcast_forw_want_rtr(bat_priv, skb, vid);

	if (ret != NET_XMIT_SUCCESS) {

		kfree_skb(skb);

		return ret;

	}



	consume_skb(skb);

	return ret;

}