net: Add batman-adv meshing protocol

B.A.T.M.A.N. (better approach to mobile ad-hoc networking) is a routing
protocol for multi-hop ad-hoc mesh networks. The networks may be wired or
wireless. See http://www.open-mesh.org/ for more information and user space
tools.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 273 insertions, 0 deletions

diff --git a/net/batman-adv/aggregation.c b/net/batman-adv/aggregation.c
new file mode 100644
index 0000000..3850a3e
--- /dev/null
+++ b/net/batman-adv/aggregation.c
@@ -0,0 +1,273 @@
+/*
+ * Copyright (C) 2007-2010 B.A.T.M.A.N. contributors:
+ *
+ * Marek Lindner, Simon Wunderlich
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA
+ *
+ */
+
+#include "main.h"
+#include "aggregation.h"
+#include "send.h"
+#include "routing.h"
+
+/* calculate the size of the hna information for a given packet */
+static int hna_len(struct batman_packet *batman_packet)
+{
+	return batman_packet->num_hna * ETH_ALEN;
+}
+
+/* return true if new_packet can be aggregated with forw_packet */
+static bool can_aggregate_with(struct batman_packet *new_batman_packet,
+			       int packet_len,
+			       unsigned long send_time,
+			       bool directlink,
+			       struct batman_if *if_incoming,
+			       struct forw_packet *forw_packet)
+{
+	struct batman_packet *batman_packet =
+		(struct batman_packet *)forw_packet->skb->data;
+	int aggregated_bytes = forw_packet->packet_len + packet_len;
+
+	/**
+	 * we can aggregate the current packet to this aggregated packet
+	 * if:
+	 *
+	 * - the send time is within our MAX_AGGREGATION_MS time
+	 * - the resulting packet wont be bigger than
+	 *   MAX_AGGREGATION_BYTES
+	 */
+
+	if (time_before(send_time, forw_packet->send_time) &&
+	    time_after_eq(send_time + msecs_to_jiffies(MAX_AGGREGATION_MS),
+					forw_packet->send_time) &&
+	    (aggregated_bytes <= MAX_AGGREGATION_BYTES)) {
+
+		/**
+		 * check aggregation compatibility
+		 * -> direct link packets are broadcasted on
+		 *    their interface only
+		 * -> aggregate packet if the current packet is
+		 *    a "global" packet as well as the base
+		 *    packet
+		 */
+
+		/* packets without direct link flag and high TTL
+		 * are flooded through the net  */
+		if ((!directlink) &&
+		    (!(batman_packet->flags & DIRECTLINK)) &&
+		    (batman_packet->ttl != 1) &&
+
+		    /* own packets originating non-primary
+		     * interfaces leave only that interface */
+		    ((!forw_packet->own) ||
+		     (forw_packet->if_incoming->if_num == 0)))
+			return true;
+
+		/* if the incoming packet is sent via this one
+		 * interface only - we still can aggregate */
+		if ((directlink) &&
+		    (new_batman_packet->ttl == 1) &&
+		    (forw_packet->if_incoming == if_incoming) &&
+
+		    /* packets from direct neighbors or
+		     * own secondary interface packets
+		     * (= secondary interface packets in general) */
+		    (batman_packet->flags & DIRECTLINK ||
+		     (forw_packet->own &&
+		      forw_packet->if_incoming->if_num != 0)))
+			return true;
+	}
+
+	return false;
+}
+
+#define atomic_dec_not_zero(v)          atomic_add_unless((v), -1, 0)
+/* create a new aggregated packet and add this packet to it */
+static void new_aggregated_packet(unsigned char *packet_buff, int packet_len,
+				  unsigned long send_time, bool direct_link,
+				  struct batman_if *if_incoming,
+				  int own_packet)
+{
+	struct bat_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
+	struct forw_packet *forw_packet_aggr;
+	unsigned char *skb_buff;
+
+	/* own packet should always be scheduled */
+	if (!own_packet) {
+		if (!atomic_dec_not_zero(&bat_priv->batman_queue_left)) {
+			bat_dbg(DBG_BATMAN, bat_priv,
+				"batman packet queue full\n");
+			return;
+		}
+	}
+
+	forw_packet_aggr = kmalloc(sizeof(struct forw_packet), GFP_ATOMIC);
+	if (!forw_packet_aggr) {
+		if (!own_packet)
+			atomic_inc(&bat_priv->batman_queue_left);
+		return;
+	}
+
+	if ((atomic_read(&bat_priv->aggregated_ogms)) &&
+	    (packet_len < MAX_AGGREGATION_BYTES))
+		forw_packet_aggr->skb = dev_alloc_skb(MAX_AGGREGATION_BYTES +
+						      sizeof(struct ethhdr));
+	else
+		forw_packet_aggr->skb = dev_alloc_skb(packet_len +
+						      sizeof(struct ethhdr));
+
+	if (!forw_packet_aggr->skb) {
+		if (!own_packet)
+			atomic_inc(&bat_priv->batman_queue_left);
+		kfree(forw_packet_aggr);
+		return;
+	}
+	skb_reserve(forw_packet_aggr->skb, sizeof(struct ethhdr));
+
+	INIT_HLIST_NODE(&forw_packet_aggr->list);
+
+	skb_buff = skb_put(forw_packet_aggr->skb, packet_len);
+	forw_packet_aggr->packet_len = packet_len;
+	memcpy(skb_buff, packet_buff, packet_len);
+
+	forw_packet_aggr->own = own_packet;
+	forw_packet_aggr->if_incoming = if_incoming;
+	forw_packet_aggr->num_packets = 0;
+	forw_packet_aggr->direct_link_flags = 0;
+	forw_packet_aggr->send_time = send_time;
+
+	/* save packet direct link flag status */
+	if (direct_link)
+		forw_packet_aggr->direct_link_flags |= 1;
+
+	/* add new packet to packet list */
+	spin_lock_bh(&bat_priv->forw_bat_list_lock);
+	hlist_add_head(&forw_packet_aggr->list, &bat_priv->forw_bat_list);
+	spin_unlock_bh(&bat_priv->forw_bat_list_lock);
+
+	/* start timer for this packet */
+	INIT_DELAYED_WORK(&forw_packet_aggr->delayed_work,
+			  send_outstanding_bat_packet);
+	queue_delayed_work(bat_event_workqueue,
+			   &forw_packet_aggr->delayed_work,
+			   send_time - jiffies);
+}
+
+/* aggregate a new packet into the existing aggregation */
+static void aggregate(struct forw_packet *forw_packet_aggr,
+		      unsigned char *packet_buff,
+		      int packet_len,
+		      bool direct_link)
+{
+	unsigned char *skb_buff;
+
+	skb_buff = skb_put(forw_packet_aggr->skb, packet_len);
+	memcpy(skb_buff, packet_buff, packet_len);
+	forw_packet_aggr->packet_len += packet_len;
+	forw_packet_aggr->num_packets++;
+
+	/* save packet direct link flag status */
+	if (direct_link)
+		forw_packet_aggr->direct_link_flags |=
+			(1 << forw_packet_aggr->num_packets);
+}
+
+void add_bat_packet_to_list(struct bat_priv *bat_priv,
+			    unsigned char *packet_buff, int packet_len,
+			    struct batman_if *if_incoming, char own_packet,
+			    unsigned long send_time)
+{
+	/**
+	 * _aggr -> pointer to the packet we want to aggregate with
+	 * _pos -> pointer to the position in the queue
+	 */
+	struct forw_packet *forw_packet_aggr = NULL, *forw_packet_pos = NULL;
+	struct hlist_node *tmp_node;
+	struct batman_packet *batman_packet =
+		(struct batman_packet *)packet_buff;
+	bool direct_link = batman_packet->flags & DIRECTLINK ? 1 : 0;
+
+	/* find position for the packet in the forward queue */
+	spin_lock_bh(&bat_priv->forw_bat_list_lock);
+	/* own packets are not to be aggregated */
+	if ((atomic_read(&bat_priv->aggregated_ogms)) && (!own_packet)) {
+		hlist_for_each_entry(forw_packet_pos, tmp_node,
+				     &bat_priv->forw_bat_list, list) {
+			if (can_aggregate_with(batman_packet,
+					       packet_len,
+					       send_time,
+					       direct_link,
+					       if_incoming,
+					       forw_packet_pos)) {
+				forw_packet_aggr = forw_packet_pos;
+				break;
+			}
+		}
+	}
+
+	/* nothing to aggregate with - either aggregation disabled or no
+	 * suitable aggregation packet found */
+	if (!forw_packet_aggr) {
+		/* the following section can run without the lock */
+		spin_unlock_bh(&bat_priv->forw_bat_list_lock);
+
+		/**
+		 * if we could not aggregate this packet with one of the others
+		 * we hold it back for a while, so that it might be aggregated
+		 * later on
+		 */
+		if ((!own_packet) &&
+		    (atomic_read(&bat_priv->aggregated_ogms)))
+			send_time += msecs_to_jiffies(MAX_AGGREGATION_MS);
+
+		new_aggregated_packet(packet_buff, packet_len,
+				      send_time, direct_link,
+				      if_incoming, own_packet);
+	} else {
+		aggregate(forw_packet_aggr,
+			  packet_buff, packet_len,
+			  direct_link);
+		spin_unlock_bh(&bat_priv->forw_bat_list_lock);
+	}
+}
+
+/* unpack the aggregated packets and process them one by one */
+void receive_aggr_bat_packet(struct ethhdr *ethhdr, unsigned char *packet_buff,
+			     int packet_len, struct batman_if *if_incoming)
+{
+	struct batman_packet *batman_packet;
+	int buff_pos = 0;
+	unsigned char *hna_buff;
+
+	batman_packet = (struct batman_packet *)packet_buff;
+
+	do {
+		/* network to host order for our 32bit seqno, and the
+		   orig_interval. */
+		batman_packet->seqno = ntohl(batman_packet->seqno);
+
+		hna_buff = packet_buff + buff_pos + BAT_PACKET_LEN;
+		receive_bat_packet(ethhdr, batman_packet,
+				   hna_buff, hna_len(batman_packet),
+				   if_incoming);
+
+		buff_pos += BAT_PACKET_LEN + hna_len(batman_packet);
+		batman_packet = (struct batman_packet *)
+			(packet_buff + buff_pos);
+	} while (aggregated_packet(buff_pos, packet_len,
+				   batman_packet->num_hna));
+}