Commit 3111beed authored by Linus Lüssing's avatar Linus Lüssing Committed by Simon Wunderlich
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batman-adv: Simple (re)broadcast avoidance 



With this patch, (re)broadcasting on a specific interfaces is avoided:

* No neighbor: There is no need to broadcast on an interface if there
  is no node behind it.

* Single neighbor is source: If there is just one neighbor on an
  interface and if this neighbor is the one we actually got this
  broadcast packet from, then we do not need to echo it back.

* Single neighbor is originator: If there is just one neighbor on
  an interface and if this neighbor is the originator of this
  broadcast packet, then we do not need to echo it back.

Goodies for BATMAN V:

("Upgrade your BATMAN IV network to V now to get these for free!")

Thanks to the split of OGMv1 into two packet types, OGMv2 and ELP
that is, we can now apply the same optimizations stated above to OGMv2
packets, too.

Furthermore, with BATMAN V, rebroadcasts can be reduced in certain
multi interface cases, too, where BATMAN IV cannot. This is thanks to
the removal of the "secondary interface originator" concept in BATMAN V.

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 cbebd363

net/batman-adv/bat_v_ogm.c

+56 −0
Original line number Diff line number Diff line
@@ -140,6 +140,7 @@ static void batadv_v_ogm_send(struct work_struct *work) 
	unsigned char *ogm_buff, *pkt_buff;

	int ogm_buff_len;

	u16 tvlv_len = 0;

	int ret;



	bat_v = container_of(work, struct batadv_priv_bat_v, ogm_wq.work);

	bat_priv = container_of(bat_v, struct batadv_priv, bat_v);
@@ -182,6 +183,31 @@ static void batadv_v_ogm_send(struct work_struct *work) 
		if (!kref_get_unless_zero(&hard_iface->refcount))

			continue;



		ret = batadv_hardif_no_broadcast(hard_iface, NULL, NULL);

		if (ret) {

			char *type;



			switch (ret) {

			case BATADV_HARDIF_BCAST_NORECIPIENT:

				type = "no neighbor";

				break;

			case BATADV_HARDIF_BCAST_DUPFWD:

				type = "single neighbor is source";

				break;

			case BATADV_HARDIF_BCAST_DUPORIG:

				type = "single neighbor is originator";

				break;

			default:

				type = "unknown";

			}



			batadv_dbg(BATADV_DBG_BATMAN, bat_priv, "OGM2 from ourselve on %s surpressed: %s\n",

				   hard_iface->net_dev->name, type);



			batadv_hardif_put(hard_iface);

			continue;

		}



		batadv_dbg(BATADV_DBG_BATMAN, bat_priv,

			   "Sending own OGM2 packet (originator %pM, seqno %u, throughput %u, TTL %d) on interface %s [%pM]\n",

			   ogm_packet->orig, ntohl(ogm_packet->seqno),
@@ -651,6 +677,7 @@ static void batadv_v_ogm_process(const struct sk_buff *skb, int ogm_offset, 
	struct batadv_hard_iface *hard_iface;

	struct batadv_ogm2_packet *ogm_packet;

	u32 ogm_throughput, link_throughput, path_throughput;

	int ret;



	ethhdr = eth_hdr(skb);

	ogm_packet = (struct batadv_ogm2_packet *)(skb->data + ogm_offset);
@@ -716,6 +743,35 @@ static void batadv_v_ogm_process(const struct sk_buff *skb, int ogm_offset, 
		if (!kref_get_unless_zero(&hard_iface->refcount))

			continue;



		ret = batadv_hardif_no_broadcast(hard_iface,

						 ogm_packet->orig,

						 hardif_neigh->orig);



		if (ret) {

			char *type;



			switch (ret) {

			case BATADV_HARDIF_BCAST_NORECIPIENT:

				type = "no neighbor";

				break;

			case BATADV_HARDIF_BCAST_DUPFWD:

				type = "single neighbor is source";

				break;

			case BATADV_HARDIF_BCAST_DUPORIG:

				type = "single neighbor is originator";

				break;

			default:

				type = "unknown";

			}



			batadv_dbg(BATADV_DBG_BATMAN, bat_priv, "OGM2 packet from %pM on %s surpressed: %s\n",

				   ogm_packet->orig, hard_iface->net_dev->name,

				   type);



			batadv_hardif_put(hard_iface);

			continue;

		}



		batadv_v_ogm_process_per_outif(bat_priv, ethhdr, ogm_packet,

					       orig_node, neigh_node,

					       if_incoming, hard_iface);

net/batman-adv/hard-interface.c

+52 −0
Original line number Diff line number Diff line
@@ -228,6 +228,58 @@ bool batadv_is_wifi_netdev(struct net_device *net_device) 
	return false;

}



/**

 * batadv_hardif_no_broadcast - check whether (re)broadcast is necessary

 * @if_outgoing: the outgoing interface checked and considered for (re)broadcast

 * @orig_addr: the originator of this packet

 * @orig_neigh: originator address of the forwarder we just got the packet from

 *  (NULL if we originated)

 *

 * Checks whether a packet needs to be (re)broadcasted on the given interface.

 *

 * Return:

 *	BATADV_HARDIF_BCAST_NORECIPIENT: No neighbor on interface

 *	BATADV_HARDIF_BCAST_DUPFWD: Just one neighbor, but it is the forwarder

 *	BATADV_HARDIF_BCAST_DUPORIG: Just one neighbor, but it is the originator

 *	BATADV_HARDIF_BCAST_OK: Several neighbors, must broadcast

 */

int batadv_hardif_no_broadcast(struct batadv_hard_iface *if_outgoing,

			       u8 *orig_addr, u8 *orig_neigh)

{

	struct batadv_hardif_neigh_node *hardif_neigh;

	struct hlist_node *first;

	int ret = BATADV_HARDIF_BCAST_OK;



	rcu_read_lock();



	/* 0 neighbors -> no (re)broadcast */

	first = rcu_dereference(hlist_first_rcu(&if_outgoing->neigh_list));

	if (!first) {

		ret = BATADV_HARDIF_BCAST_NORECIPIENT;

		goto out;

	}



	/* >1 neighbors -> (re)brodcast */

	if (rcu_dereference(hlist_next_rcu(first)))

		goto out;



	hardif_neigh = hlist_entry(first, struct batadv_hardif_neigh_node,

				   list);



	/* 1 neighbor, is the originator -> no rebroadcast */

	if (orig_addr && batadv_compare_eth(hardif_neigh->orig, orig_addr)) {

		ret = BATADV_HARDIF_BCAST_DUPORIG;

	/* 1 neighbor, is the one we received from -> no rebroadcast */

	} else if (orig_neigh &&

		   batadv_compare_eth(hardif_neigh->orig, orig_neigh)) {

		ret = BATADV_HARDIF_BCAST_DUPFWD;

	}



out:

	rcu_read_unlock();

	return ret;

}



static struct batadv_hard_iface *

batadv_hardif_get_active(const struct net_device *soft_iface)

{

net/batman-adv/hard-interface.h

+16 −0
Original line number Diff line number Diff line
@@ -39,6 +39,20 @@ enum batadv_hard_if_state { 
	BATADV_IF_I_WANT_YOU,

};



/**

 * enum batadv_hard_if_bcast - broadcast avoidance options

 * @BATADV_HARDIF_BCAST_OK: Do broadcast on according hard interface

 * @BATADV_HARDIF_BCAST_NORECIPIENT: Broadcast not needed, there is no recipient

 * @BATADV_HARDIF_BCAST_DUPFWD: There is just the neighbor we got it from

 * @BATADV_HARDIF_BCAST_DUPORIG: There is just the originator

 */

enum batadv_hard_if_bcast {

	BATADV_HARDIF_BCAST_OK = 0,

	BATADV_HARDIF_BCAST_NORECIPIENT,

	BATADV_HARDIF_BCAST_DUPFWD,

	BATADV_HARDIF_BCAST_DUPORIG,

};



/**

 * enum batadv_hard_if_cleanup - Cleanup modi for soft_iface after slave removal

 * @BATADV_IF_CLEANUP_KEEP: Don't automatically delete soft-interface
@@ -63,6 +77,8 @@ void batadv_hardif_remove_interfaces(void); 
int batadv_hardif_min_mtu(struct net_device *soft_iface);

void batadv_update_min_mtu(struct net_device *soft_iface);

void batadv_hardif_release(struct kref *ref);

int batadv_hardif_no_broadcast(struct batadv_hard_iface *if_outgoing,

			       u8 *orig_addr, u8 *orig_neigh);



/**

 * batadv_hardif_put - decrement the hard interface refcounter and possibly

net/batman-adv/originator.c

+9 −4
Original line number Diff line number Diff line
@@ -512,12 +512,14 @@ batadv_neigh_node_get(const struct batadv_orig_node *orig_node, 
 * batadv_hardif_neigh_create - create a hardif neighbour node

 * @hard_iface: the interface this neighbour is connected to

 * @neigh_addr: the interface address of the neighbour to retrieve

 * @orig_node: originator object representing the neighbour

 *

 * Return: the hardif neighbour node if found or created or NULL otherwise.

 */

static struct batadv_hardif_neigh_node *

batadv_hardif_neigh_create(struct batadv_hard_iface *hard_iface,

			   const u8 *neigh_addr)

			   const u8 *neigh_addr,

			   struct batadv_orig_node *orig_node)

{

	struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);

	struct batadv_hardif_neigh_node *hardif_neigh;
@@ -536,6 +538,7 @@ batadv_hardif_neigh_create(struct batadv_hard_iface *hard_iface, 
	kref_get(&hard_iface->refcount);

	INIT_HLIST_NODE(&hardif_neigh->list);

	ether_addr_copy(hardif_neigh->addr, neigh_addr);

	ether_addr_copy(hardif_neigh->orig, orig_node->orig);

	hardif_neigh->if_incoming = hard_iface;

	hardif_neigh->last_seen = jiffies;
@@ -556,12 +559,14 @@ out: 
 *  node

 * @hard_iface: the interface this neighbour is connected to

 * @neigh_addr: the interface address of the neighbour to retrieve

 * @orig_node: originator object representing the neighbour

 *

 * Return: the hardif neighbour node if found or created or NULL otherwise.

 */

static struct batadv_hardif_neigh_node *

batadv_hardif_neigh_get_or_create(struct batadv_hard_iface *hard_iface,

				  const u8 *neigh_addr)

				  const u8 *neigh_addr,

				  struct batadv_orig_node *orig_node)

{

	struct batadv_hardif_neigh_node *hardif_neigh;
@@ -570,7 +575,7 @@ batadv_hardif_neigh_get_or_create(struct batadv_hard_iface *hard_iface, 
	if (hardif_neigh)

		return hardif_neigh;



	return batadv_hardif_neigh_create(hard_iface, neigh_addr);

	return batadv_hardif_neigh_create(hard_iface, neigh_addr, orig_node);

}



/**
@@ -630,7 +635,7 @@ batadv_neigh_node_create(struct batadv_orig_node *orig_node, 
		goto out;



	hardif_neigh = batadv_hardif_neigh_get_or_create(hard_iface,

							 neigh_addr);

							 neigh_addr, orig_node);

	if (!hardif_neigh)

		goto out;

net/batman-adv/routing.c

+1 −1
Original line number Diff line number Diff line
@@ -1170,7 +1170,7 @@ int batadv_recv_bcast_packet(struct sk_buff *skb, 
	batadv_skb_set_priority(skb, sizeof(struct batadv_bcast_packet));



	/* rebroadcast packet */

	batadv_add_bcast_packet_to_list(bat_priv, skb, 1);

	batadv_add_bcast_packet_to_list(bat_priv, skb, 1, false);



	/* don't hand the broadcast up if it is from an originator

	 * from the same backbone.

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