[PATCH 2/2] batman-adv: BATMAN_V: aggregate OGMv2 packets

["Linus Lüssing" <linus.luessing@c0d3.blue>]

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 36f78889..a743c67d 100644
--- a/net/batman-adv/bat_v_ogm.c
+++ b/net/batman-adv/bat_v_ogm.c
@@ -180,15 +180,40 @@ 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.
  */
 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;
+
+	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);
 }
 
 /**
-- 
2.22.0