In preparation for the OGMv2 packet aggregation, hold OGMv2 packets for up to BATADV_MAX_AGGREGATION_MS milliseconds (100ms) on per hard-interface queues, before transmitting.

This allows us to later squash multiple OGMs into a single frame and transmission for reduced overhead.

Signed-off-by: Linus Lüssing linus.luessing@c0d3.blue --- net/batman-adv/bat_v.c | 7 ++ net/batman-adv/bat_v_ogm.c | 152 ++++++++++++++++++++++++++++++++++++- net/batman-adv/bat_v_ogm.h | 3 + net/batman-adv/types.h | 15 ++++ 4 files changed, 175 insertions(+), 2 deletions(-)

diff --git a/net/batman-adv/bat_v.c b/net/batman-adv/bat_v.c index 22672cb3..64054edc 100644 --- a/net/batman-adv/bat_v.c +++ b/net/batman-adv/bat_v.c @@ -79,6 +79,7 @@ static int batadv_v_iface_enable(struct batadv_hard_iface *hard_iface)

static void batadv_v_iface_disable(struct batadv_hard_iface *hard_iface) { + batadv_v_ogm_iface_disable(hard_iface); batadv_v_elp_iface_disable(hard_iface); }

@@ -1081,6 +1082,12 @@ void batadv_v_hardif_init(struct batadv_hard_iface *hard_iface) */ atomic_set(&hard_iface->bat_v.throughput_override, 0); atomic_set(&hard_iface->bat_v.elp_interval, 500); + + hard_iface->bat_v.aggr_len = 0; + skb_queue_head_init(&hard_iface->bat_v.aggr_list); + spin_lock_init(&hard_iface->bat_v.aggr_list_lock); + INIT_DELAYED_WORK(&hard_iface->bat_v.aggr_wq, + batadv_v_ogm_aggr_work); }

/** diff --git a/net/batman-adv/bat_v_ogm.c b/net/batman-adv/bat_v_ogm.c index fad95ef6..c33041f6 100644 --- a/net/batman-adv/bat_v_ogm.c +++ b/net/batman-adv/bat_v_ogm.c @@ -23,6 +23,7 @@ #include <linux/rcupdate.h> #include <linux/skbuff.h> #include <linux/slab.h> +#include <linux/spinlock.h> #include <linux/stddef.h> #include <linux/string.h> #include <linux/types.h> @@ -76,6 +77,20 @@ struct batadv_orig_node *batadv_v_ogm_orig_get(struct batadv_priv *bat_priv, return orig_node; }

+/** + * batadv_v_ogm_start_queue_timer() - restart the OGM aggregation timer + * @hard_iface: the interface to use to send the OGM + */ +static void batadv_v_ogm_start_queue_timer(struct batadv_hard_iface *hard_iface) +{ + unsigned int msecs = BATADV_MAX_AGGREGATION_MS * 1000; + + /* msecs * [0.9, 1.1] */ + msecs += prandom_u32() % (msecs / 5) - (msecs / 10); + queue_delayed_work(batadv_event_workqueue, &hard_iface->bat_v.aggr_wq, + msecs_to_jiffies(msecs / 1000)); +} + /** * batadv_v_ogm_start_timer() - restart the OGM sending timer * @bat_priv: the bat priv with all the soft interface information @@ -115,6 +130,104 @@ static void batadv_v_ogm_send_to_if(struct sk_buff *skb, batadv_send_broadcast_skb(skb, hard_iface); }

+/** + * batadv_v_ogm_len() - OGMv2 packet length + * @skb: the OGM to check + * + * Return: Length of the given OGMv2 packet, including tvlv length, excluding + * ethernet frame length. + */ +static inline unsigned int batadv_v_ogm_len(struct sk_buff *skb) +{ + struct batadv_ogm2_packet *ogm_packet; + + ogm_packet = (struct batadv_ogm2_packet *)skb->data; + return BATADV_OGM2_HLEN + ntohs(ogm_packet->tvlv_len); +} + +/** + * batadv_v_ogm_queue_left() - check if given OGM still fits aggregation queue + * @skb: the OGM to check + * @hard_iface: the interface to use to send the OGM + * + * Caller needs to hold the hard_iface->bat_v.aggr_list_lock. + * + * Return: True, if the given OGMv2 packet still fits, false otherwise. + */ +static bool batadv_v_ogm_queue_left(struct sk_buff *skb, + struct batadv_hard_iface *hard_iface) +{ + unsigned int max = min_t(unsigned int, hard_iface->net_dev->mtu, + BATADV_MAX_AGGREGATION_BYTES); + unsigned int ogm_len = batadv_v_ogm_len(skb); + + lockdep_assert_held(&hard_iface->bat_v.aggr_list_lock); + + return hard_iface->bat_v.aggr_len + ogm_len <= max; +} + +/** + * batadv_v_ogm_aggr_list_free - free all elements in an aggregation queue + * @hard_iface: the interface holding the aggregation queue + * + * Empties the OGMv2 aggregation queue and frees all the skbs it contained. + * + * Caller needs to hold the hard_iface->bat_v.aggr_list_lock. + */ +static void batadv_v_ogm_aggr_list_free(struct batadv_hard_iface *hard_iface) +{ + struct sk_buff *skb; + + lockdep_assert_held(&hard_iface->bat_v.aggr_list_lock); + + while ((skb = skb_dequeue(&hard_iface->bat_v.aggr_list))) + kfree_skb(skb); + + hard_iface->bat_v.aggr_len = 0; +} + +/** + * batadv_v_ogm_aggr_send() - flush & send aggregation queue + * @hard_iface: the interface with the aggregation queue to flush + * + * Caller needs to hold the hard_iface->bat_v.aggr_list_lock. + */ +static void batadv_v_ogm_aggr_send(struct batadv_hard_iface *hard_iface) +{ + struct sk_buff *skb; + + lockdep_assert_held(&hard_iface->bat_v.aggr_list_lock); + + while ((skb = skb_dequeue(&hard_iface->bat_v.aggr_list))) { + hard_iface->bat_v.aggr_len -= batadv_v_ogm_len(skb); + batadv_v_ogm_send_to_if(skb, hard_iface); + } +} + +/** + * batadv_v_ogm_queue_on_if() - queue a batman ogm on a given interface + * @skb: the OGM to queue + * @hard_iface: the interface to queue the OGM on + */ +static void batadv_v_ogm_queue_on_if(struct sk_buff *skb, + struct batadv_hard_iface *hard_iface) +{ + struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface); + + if (!atomic_read(&bat_priv->aggregated_ogms)) { + batadv_v_ogm_send_to_if(skb, hard_iface); + return; + } + + spin_lock_bh(&hard_iface->bat_v.aggr_list_lock); + if (!batadv_v_ogm_queue_left(skb, hard_iface)) + batadv_v_ogm_aggr_send(hard_iface); + + hard_iface->bat_v.aggr_len += batadv_v_ogm_len(skb); + skb_queue_tail(&hard_iface->bat_v.aggr_list, skb); + spin_unlock_bh(&hard_iface->bat_v.aggr_list_lock); +} + /** * batadv_v_ogm_send() - periodic worker broadcasting the own OGM * @work: work queue item @@ -210,7 +323,7 @@ static void batadv_v_ogm_send(struct work_struct *work) break; }

- batadv_v_ogm_send_to_if(skb_tmp, hard_iface); + batadv_v_ogm_queue_on_if(skb_tmp, hard_iface); batadv_hardif_put(hard_iface); } rcu_read_unlock(); @@ -223,6 +336,27 @@ static void batadv_v_ogm_send(struct work_struct *work) return; }

+/** + * batadv_v_ogm_aggr_work() - OGM queue periodic task per interface + * @work: work queue item + * + * Emits aggregated OGM message in regular intervals. + */ +void batadv_v_ogm_aggr_work(struct work_struct *work) +{ + struct batadv_hard_iface_bat_v *batv; + struct batadv_hard_iface *hard_iface; + + batv = container_of(work, struct batadv_hard_iface_bat_v, aggr_wq.work); + hard_iface = container_of(batv, struct batadv_hard_iface, bat_v); + + spin_lock_bh(&hard_iface->bat_v.aggr_list_lock); + batadv_v_ogm_aggr_send(hard_iface); + spin_unlock_bh(&hard_iface->bat_v.aggr_list_lock); + + batadv_v_ogm_start_queue_timer(hard_iface); +} + /** * batadv_v_ogm_iface_enable() - prepare an interface for B.A.T.M.A.N. V * @hard_iface: the interface to prepare @@ -235,11 +369,25 @@ int batadv_v_ogm_iface_enable(struct batadv_hard_iface *hard_iface) { struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);

+ batadv_v_ogm_start_queue_timer(hard_iface); batadv_v_ogm_start_timer(bat_priv);

return 0; }

+/** + * batadv_v_ogm_iface_disable() - release OGM interface private resources + * @hard_iface: interface for which the resources have to be released + */ +void batadv_v_ogm_iface_disable(struct batadv_hard_iface *hard_iface) +{ + cancel_delayed_work_sync(&hard_iface->bat_v.aggr_wq); + + spin_lock_bh(&hard_iface->bat_v.aggr_list_lock); + batadv_v_ogm_aggr_list_free(hard_iface); + spin_unlock_bh(&hard_iface->bat_v.aggr_list_lock); +} + /** * batadv_v_ogm_primary_iface_set() - set a new primary interface * @primary_iface: the new primary interface @@ -382,7 +530,7 @@ static void batadv_v_ogm_forward(struct batadv_priv *bat_priv, if_outgoing->net_dev->name, ntohl(ogm_forward->throughput), ogm_forward->ttl, if_incoming->net_dev->name);

- batadv_v_ogm_send_to_if(skb, if_outgoing); + batadv_v_ogm_queue_on_if(skb, if_outgoing);

out: if (orig_ifinfo) diff --git a/net/batman-adv/bat_v_ogm.h b/net/batman-adv/bat_v_ogm.h index 2a50df7f..bf16d040 100644 --- a/net/batman-adv/bat_v_ogm.h +++ b/net/batman-adv/bat_v_ogm.h @@ -11,10 +11,13 @@

#include <linux/skbuff.h> #include <linux/types.h> +#include <linux/workqueue.h>

int batadv_v_ogm_init(struct batadv_priv *bat_priv); void batadv_v_ogm_free(struct batadv_priv *bat_priv); +void batadv_v_ogm_aggr_work(struct work_struct *work); int batadv_v_ogm_iface_enable(struct batadv_hard_iface *hard_iface); +void batadv_v_ogm_iface_disable(struct batadv_hard_iface *hard_iface); struct batadv_orig_node *batadv_v_ogm_orig_get(struct batadv_priv *bat_priv, const u8 *addr); void batadv_v_ogm_primary_iface_set(struct batadv_hard_iface *primary_iface); diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h index 6ae139d7..3e286e0d 100644 --- a/net/batman-adv/types.h +++ b/net/batman-adv/types.h @@ -117,6 +117,21 @@ struct batadv_hard_iface_bat_v { /** @elp_wq: workqueue used to schedule ELP transmissions */ struct delayed_work elp_wq;

+ /** @aggr_wq: workqueue used to transmit queued OGM packets */ + struct delayed_work aggr_wq; + + /** @aggr_list: queue for to be aggregated OGM packets */ + struct sk_buff_head aggr_list; + + /** + * @aggr_len: length of the OGM aggregate (excluding ethernet frame + * size) + */ + unsigned int aggr_len; + + /** @aggr_list_lock: protects aggr_list */ + spinlock_t aggr_list_lock; + /** * @throughput_override: throughput override to disable link * auto-detection

Instead of transmitting individual OGMv2 packets from the aggregation queue merge those OGMv2 packets into a single one and transmit this aggregate instead.

This reduces overhead as it saves an ethernet header and a transmission per aggregated OGMv2 packet.

Signed-off-by: Linus Lüssing linus.luessing@c0d3.blue --- net/batman-adv/bat_v_ogm.c | 29 +++++++++++++++++++++++++++-- 1 file changed, 27 insertions(+), 2 deletions(-)

diff --git a/net/batman-adv/bat_v_ogm.c b/net/batman-adv/bat_v_ogm.c index c33041f6..069fdada 100644 --- a/net/batman-adv/bat_v_ogm.c +++ b/net/batman-adv/bat_v_ogm.c @@ -190,18 +190,43 @@ static void batadv_v_ogm_aggr_list_free(struct batadv_hard_iface *hard_iface) * batadv_v_ogm_aggr_send() - flush & send aggregation queue * @hard_iface: the interface with the aggregation queue to flush * + * Aggregates all OGMv2 packets currently in the aggregation queue into a + * single OGMv2 packet and transmits this aggregate. + * + * The aggregation queue is empty after this call. + * * Caller needs to hold the hard_iface->bat_v.aggr_list_lock. */ static void batadv_v_ogm_aggr_send(struct batadv_hard_iface *hard_iface) { - struct sk_buff *skb; + unsigned int aggr_len = hard_iface->bat_v.aggr_len; + struct sk_buff *skb, *skb_aggr; + unsigned int ogm_len;

lockdep_assert_held(&hard_iface->bat_v.aggr_list_lock);

+ if (!aggr_len) + return; + + skb_aggr = dev_alloc_skb(aggr_len + ETH_HLEN + NET_IP_ALIGN); + if (!skb_aggr) { + batadv_v_ogm_aggr_list_free(hard_iface); + return; + } + + skb_reserve(skb_aggr, ETH_HLEN + NET_IP_ALIGN); + skb_reset_network_header(skb_aggr); + while ((skb = skb_dequeue(&hard_iface->bat_v.aggr_list))) { hard_iface->bat_v.aggr_len -= batadv_v_ogm_len(skb); - batadv_v_ogm_send_to_if(skb, hard_iface); + + ogm_len = batadv_v_ogm_len(skb); + skb_put_data(skb_aggr, skb->data, ogm_len); + + consume_skb(skb); } + + batadv_v_ogm_send_to_if(skb_aggr, hard_iface); }

/**