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, 651 insertions, 0 deletions

diff --git a/net/batman-adv/hard-interface.c b/net/batman-adv/hard-interface.c
new file mode 100644
index 000000000000..4f95777ce080
--- /dev/null
+++ b/net/batman-adv/hard-interface.c
@@ -0,0 +1,651 @@
+/*
+ * 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 "hard-interface.h"
+#include "soft-interface.h"
+#include "send.h"
+#include "translation-table.h"
+#include "routing.h"
+#include "bat_sysfs.h"
+#include "originator.h"
+#include "hash.h"
+
+#include <linux/if_arp.h>
+
+/* protect update critical side of if_list - but not the content */
+static DEFINE_SPINLOCK(if_list_lock);
+
+static void hardif_free_rcu(struct rcu_head *rcu)
+{
+	struct batman_if *batman_if;
+
+	batman_if = container_of(rcu, struct batman_if, rcu);
+	dev_put(batman_if->net_dev);
+	kref_put(&batman_if->refcount, hardif_free_ref);
+}
+
+struct batman_if *get_batman_if_by_netdev(struct net_device *net_dev)
+{
+	struct batman_if *batman_if;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(batman_if, &if_list, list) {
+		if (batman_if->net_dev == net_dev)
+			goto out;
+	}
+
+	batman_if = NULL;
+
+out:
+	if (batman_if)
+		kref_get(&batman_if->refcount);
+
+	rcu_read_unlock();
+	return batman_if;
+}
+
+static int is_valid_iface(struct net_device *net_dev)
+{
+	if (net_dev->flags & IFF_LOOPBACK)
+		return 0;
+
+	if (net_dev->type != ARPHRD_ETHER)
+		return 0;
+
+	if (net_dev->addr_len != ETH_ALEN)
+		return 0;
+
+	/* no batman over batman */
+#ifdef HAVE_NET_DEVICE_OPS
+	if (net_dev->netdev_ops->ndo_start_xmit == interface_tx)
+		return 0;
+#else
+	if (net_dev->hard_start_xmit == interface_tx)
+		return 0;
+#endif
+
+	/* Device is being bridged */
+	/* if (net_dev->priv_flags & IFF_BRIDGE_PORT)
+		return 0; */
+
+	return 1;
+}
+
+static struct batman_if *get_active_batman_if(struct net_device *soft_iface)
+{
+	struct batman_if *batman_if;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(batman_if, &if_list, list) {
+		if (batman_if->soft_iface != soft_iface)
+			continue;
+
+		if (batman_if->if_status == IF_ACTIVE)
+			goto out;
+	}
+
+	batman_if = NULL;
+
+out:
+	if (batman_if)
+		kref_get(&batman_if->refcount);
+
+	rcu_read_unlock();
+	return batman_if;
+}
+
+static void update_primary_addr(struct bat_priv *bat_priv)
+{
+	struct vis_packet *vis_packet;
+
+	vis_packet = (struct vis_packet *)
+				bat_priv->my_vis_info->skb_packet->data;
+	memcpy(vis_packet->vis_orig,
+	       bat_priv->primary_if->net_dev->dev_addr, ETH_ALEN);
+	memcpy(vis_packet->sender_orig,
+	       bat_priv->primary_if->net_dev->dev_addr, ETH_ALEN);
+}
+
+static void set_primary_if(struct bat_priv *bat_priv,
+			   struct batman_if *batman_if)
+{
+	struct batman_packet *batman_packet;
+	struct batman_if *old_if;
+
+	if (batman_if)
+		kref_get(&batman_if->refcount);
+
+	old_if = bat_priv->primary_if;
+	bat_priv->primary_if = batman_if;
+
+	if (old_if)
+		kref_put(&old_if->refcount, hardif_free_ref);
+
+	if (!bat_priv->primary_if)
+		return;
+
+	batman_packet = (struct batman_packet *)(batman_if->packet_buff);
+	batman_packet->flags = PRIMARIES_FIRST_HOP;
+	batman_packet->ttl = TTL;
+
+	update_primary_addr(bat_priv);
+
+	/***
+	 * hacky trick to make sure that we send the HNA information via
+	 * our new primary interface
+	 */
+	atomic_set(&bat_priv->hna_local_changed, 1);
+}
+
+static bool hardif_is_iface_up(struct batman_if *batman_if)
+{
+	if (batman_if->net_dev->flags & IFF_UP)
+		return true;
+
+	return false;
+}
+
+static void update_mac_addresses(struct batman_if *batman_if)
+{
+	memcpy(((struct batman_packet *)(batman_if->packet_buff))->orig,
+	       batman_if->net_dev->dev_addr, ETH_ALEN);
+	memcpy(((struct batman_packet *)(batman_if->packet_buff))->prev_sender,
+	       batman_if->net_dev->dev_addr, ETH_ALEN);
+}
+
+static void check_known_mac_addr(struct net_device *net_dev)
+{
+	struct batman_if *batman_if;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(batman_if, &if_list, list) {
+		if ((batman_if->if_status != IF_ACTIVE) &&
+		    (batman_if->if_status != IF_TO_BE_ACTIVATED))
+			continue;
+
+		if (batman_if->net_dev == net_dev)
+			continue;
+
+		if (!compare_orig(batman_if->net_dev->dev_addr,
+				  net_dev->dev_addr))
+			continue;
+
+		pr_warning("The newly added mac address (%pM) already exists "
+			   "on: %s\n", net_dev->dev_addr,
+			   batman_if->net_dev->name);
+		pr_warning("It is strongly recommended to keep mac addresses "
+			   "unique to avoid problems!\n");
+	}
+	rcu_read_unlock();
+}
+
+int hardif_min_mtu(struct net_device *soft_iface)
+{
+	struct bat_priv *bat_priv = netdev_priv(soft_iface);
+	struct batman_if *batman_if;
+	/* allow big frames if all devices are capable to do so
+	 * (have MTU > 1500 + BAT_HEADER_LEN) */
+	int min_mtu = ETH_DATA_LEN;
+
+	if (atomic_read(&bat_priv->fragmentation))
+		goto out;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(batman_if, &if_list, list) {
+		if ((batman_if->if_status != IF_ACTIVE) &&
+		    (batman_if->if_status != IF_TO_BE_ACTIVATED))
+			continue;
+
+		if (batman_if->soft_iface != soft_iface)
+			continue;
+
+		min_mtu = min_t(int, batman_if->net_dev->mtu - BAT_HEADER_LEN,
+				min_mtu);
+	}
+	rcu_read_unlock();
+out:
+	return min_mtu;
+}
+
+/* adjusts the MTU if a new interface with a smaller MTU appeared. */
+void update_min_mtu(struct net_device *soft_iface)
+{
+	int min_mtu;
+
+	min_mtu = hardif_min_mtu(soft_iface);
+	if (soft_iface->mtu != min_mtu)
+		soft_iface->mtu = min_mtu;
+}
+
+static void hardif_activate_interface(struct batman_if *batman_if)
+{
+	struct bat_priv *bat_priv;
+
+	if (batman_if->if_status != IF_INACTIVE)
+		return;
+
+	bat_priv = netdev_priv(batman_if->soft_iface);
+
+	update_mac_addresses(batman_if);
+	batman_if->if_status = IF_TO_BE_ACTIVATED;
+
+	/**
+	 * the first active interface becomes our primary interface or
+	 * the next active interface after the old primay interface was removed
+	 */
+	if (!bat_priv->primary_if)
+		set_primary_if(bat_priv, batman_if);
+
+	bat_info(batman_if->soft_iface, "Interface activated: %s\n",
+		 batman_if->net_dev->name);
+
+	update_min_mtu(batman_if->soft_iface);
+	return;
+}
+
+static void hardif_deactivate_interface(struct batman_if *batman_if)
+{
+	if ((batman_if->if_status != IF_ACTIVE) &&
+	   (batman_if->if_status != IF_TO_BE_ACTIVATED))
+		return;
+
+	batman_if->if_status = IF_INACTIVE;
+
+	bat_info(batman_if->soft_iface, "Interface deactivated: %s\n",
+		 batman_if->net_dev->name);
+
+	update_min_mtu(batman_if->soft_iface);
+}
+
+int hardif_enable_interface(struct batman_if *batman_if, char *iface_name)
+{
+	struct bat_priv *bat_priv;
+	struct batman_packet *batman_packet;
+
+	if (batman_if->if_status != IF_NOT_IN_USE)
+		goto out;
+
+	batman_if->soft_iface = dev_get_by_name(&init_net, iface_name);
+
+	if (!batman_if->soft_iface) {
+		batman_if->soft_iface = softif_create(iface_name);
+
+		if (!batman_if->soft_iface)
+			goto err;
+
+		/* dev_get_by_name() increases the reference counter for us */
+		dev_hold(batman_if->soft_iface);
+	}
+
+	bat_priv = netdev_priv(batman_if->soft_iface);
+	batman_if->packet_len = BAT_PACKET_LEN;
+	batman_if->packet_buff = kmalloc(batman_if->packet_len, GFP_ATOMIC);
+
+	if (!batman_if->packet_buff) {
+		bat_err(batman_if->soft_iface, "Can't add interface packet "
+			"(%s): out of memory\n", batman_if->net_dev->name);
+		goto err;
+	}
+
+	batman_packet = (struct batman_packet *)(batman_if->packet_buff);
+	batman_packet->packet_type = BAT_PACKET;
+	batman_packet->version = COMPAT_VERSION;
+	batman_packet->flags = 0;
+	batman_packet->ttl = 2;
+	batman_packet->tq = TQ_MAX_VALUE;
+	batman_packet->num_hna = 0;
+
+	batman_if->if_num = bat_priv->num_ifaces;
+	bat_priv->num_ifaces++;
+	batman_if->if_status = IF_INACTIVE;
+	orig_hash_add_if(batman_if, bat_priv->num_ifaces);
+
+	batman_if->batman_adv_ptype.type = __constant_htons(ETH_P_BATMAN);
+	batman_if->batman_adv_ptype.func = batman_skb_recv;
+	batman_if->batman_adv_ptype.dev = batman_if->net_dev;
+	kref_get(&batman_if->refcount);
+	dev_add_pack(&batman_if->batman_adv_ptype);
+
+	atomic_set(&batman_if->seqno, 1);
+	atomic_set(&batman_if->frag_seqno, 1);
+	bat_info(batman_if->soft_iface, "Adding interface: %s\n",
+		 batman_if->net_dev->name);
+
+	if (atomic_read(&bat_priv->fragmentation) && batman_if->net_dev->mtu <
+		ETH_DATA_LEN + BAT_HEADER_LEN)
+		bat_info(batman_if->soft_iface,
+			"The MTU of interface %s is too small (%i) to handle "
+			"the transport of batman-adv packets. Packets going "
+			"over this interface will be fragmented on layer2 "
+			"which could impact the performance. Setting the MTU "
+			"to %zi would solve the problem.\n",
+			batman_if->net_dev->name, batman_if->net_dev->mtu,
+			ETH_DATA_LEN + BAT_HEADER_LEN);
+
+	if (!atomic_read(&bat_priv->fragmentation) && batman_if->net_dev->mtu <
+		ETH_DATA_LEN + BAT_HEADER_LEN)
+		bat_info(batman_if->soft_iface,
+			"The MTU of interface %s is too small (%i) to handle "
+			"the transport of batman-adv packets. If you experience"
+			" problems getting traffic through try increasing the "
+			"MTU to %zi.\n",
+			batman_if->net_dev->name, batman_if->net_dev->mtu,
+			ETH_DATA_LEN + BAT_HEADER_LEN);
+
+	if (hardif_is_iface_up(batman_if))
+		hardif_activate_interface(batman_if);
+	else
+		bat_err(batman_if->soft_iface, "Not using interface %s "
+			"(retrying later): interface not active\n",
+			batman_if->net_dev->name);
+
+	/* begin scheduling originator messages on that interface */
+	schedule_own_packet(batman_if);
+
+out:
+	return 0;
+
+err:
+	return -ENOMEM;
+}
+
+void hardif_disable_interface(struct batman_if *batman_if)
+{
+	struct bat_priv *bat_priv = netdev_priv(batman_if->soft_iface);
+
+	if (batman_if->if_status == IF_ACTIVE)
+		hardif_deactivate_interface(batman_if);
+
+	if (batman_if->if_status != IF_INACTIVE)
+		return;
+
+	bat_info(batman_if->soft_iface, "Removing interface: %s\n",
+		 batman_if->net_dev->name);
+	dev_remove_pack(&batman_if->batman_adv_ptype);
+	kref_put(&batman_if->refcount, hardif_free_ref);
+
+	bat_priv->num_ifaces--;
+	orig_hash_del_if(batman_if, bat_priv->num_ifaces);
+
+	if (batman_if == bat_priv->primary_if) {
+		struct batman_if *new_if;
+
+		new_if = get_active_batman_if(batman_if->soft_iface);
+		set_primary_if(bat_priv, new_if);
+
+		if (new_if)
+			kref_put(&new_if->refcount, hardif_free_ref);
+	}
+
+	kfree(batman_if->packet_buff);
+	batman_if->packet_buff = NULL;
+	batman_if->if_status = IF_NOT_IN_USE;
+
+	/* delete all references to this batman_if */
+	purge_orig_ref(bat_priv);
+	purge_outstanding_packets(bat_priv, batman_if);
+	dev_put(batman_if->soft_iface);
+
+	/* nobody uses this interface anymore */
+	if (!bat_priv->num_ifaces)
+		softif_destroy(batman_if->soft_iface);
+
+	batman_if->soft_iface = NULL;
+}
+
+static struct batman_if *hardif_add_interface(struct net_device *net_dev)
+{
+	struct batman_if *batman_if;
+	int ret;
+
+	ret = is_valid_iface(net_dev);
+	if (ret != 1)
+		goto out;
+
+	dev_hold(net_dev);
+
+	batman_if = kmalloc(sizeof(struct batman_if), GFP_ATOMIC);
+	if (!batman_if) {
+		pr_err("Can't add interface (%s): out of memory\n",
+		       net_dev->name);
+		goto release_dev;
+	}
+
+	ret = sysfs_add_hardif(&batman_if->hardif_obj, net_dev);
+	if (ret)
+		goto free_if;
+
+	batman_if->if_num = -1;
+	batman_if->net_dev = net_dev;
+	batman_if->soft_iface = NULL;
+	batman_if->if_status = IF_NOT_IN_USE;
+	INIT_LIST_HEAD(&batman_if->list);
+	kref_init(&batman_if->refcount);
+
+	check_known_mac_addr(batman_if->net_dev);
+
+	spin_lock(&if_list_lock);
+	list_add_tail_rcu(&batman_if->list, &if_list);
+	spin_unlock(&if_list_lock);
+
+	/* extra reference for return */
+	kref_get(&batman_if->refcount);
+	return batman_if;
+
+free_if:
+	kfree(batman_if);
+release_dev:
+	dev_put(net_dev);
+out:
+	return NULL;
+}
+
+static void hardif_remove_interface(struct batman_if *batman_if)
+{
+	/* first deactivate interface */
+	if (batman_if->if_status != IF_NOT_IN_USE)
+		hardif_disable_interface(batman_if);
+
+	if (batman_if->if_status != IF_NOT_IN_USE)
+		return;
+
+	batman_if->if_status = IF_TO_BE_REMOVED;
+	sysfs_del_hardif(&batman_if->hardif_obj);
+	call_rcu(&batman_if->rcu, hardif_free_rcu);
+}
+
+void hardif_remove_interfaces(void)
+{
+	struct batman_if *batman_if, *batman_if_tmp;
+	struct list_head if_queue;
+
+	INIT_LIST_HEAD(&if_queue);
+
+	spin_lock(&if_list_lock);
+	list_for_each_entry_safe(batman_if, batman_if_tmp, &if_list, list) {
+		list_del_rcu(&batman_if->list);
+		list_add_tail(&batman_if->list, &if_queue);
+	}
+	spin_unlock(&if_list_lock);
+
+	rtnl_lock();
+	list_for_each_entry_safe(batman_if, batman_if_tmp, &if_queue, list) {
+		hardif_remove_interface(batman_if);
+	}
+	rtnl_unlock();
+}
+
+static int hard_if_event(struct notifier_block *this,
+			 unsigned long event, void *ptr)
+{
+	struct net_device *net_dev = (struct net_device *)ptr;
+	struct batman_if *batman_if = get_batman_if_by_netdev(net_dev);
+	struct bat_priv *bat_priv;
+
+	if (!batman_if && event == NETDEV_REGISTER)
+		batman_if = hardif_add_interface(net_dev);
+
+	if (!batman_if)
+		goto out;
+
+	switch (event) {
+	case NETDEV_UP:
+		hardif_activate_interface(batman_if);
+		break;
+	case NETDEV_GOING_DOWN:
+	case NETDEV_DOWN:
+		hardif_deactivate_interface(batman_if);
+		break;
+	case NETDEV_UNREGISTER:
+		spin_lock(&if_list_lock);
+		list_del_rcu(&batman_if->list);
+		spin_unlock(&if_list_lock);
+
+		hardif_remove_interface(batman_if);
+		break;
+	case NETDEV_CHANGEMTU:
+		if (batman_if->soft_iface)
+			update_min_mtu(batman_if->soft_iface);
+		break;
+	case NETDEV_CHANGEADDR:
+		if (batman_if->if_status == IF_NOT_IN_USE)
+			goto hardif_put;
+
+		check_known_mac_addr(batman_if->net_dev);
+		update_mac_addresses(batman_if);
+
+		bat_priv = netdev_priv(batman_if->soft_iface);
+		if (batman_if == bat_priv->primary_if)
+			update_primary_addr(bat_priv);
+		break;
+	default:
+		break;
+	};
+
+hardif_put:
+	kref_put(&batman_if->refcount, hardif_free_ref);
+out:
+	return NOTIFY_DONE;
+}
+
+/* receive a packet with the batman ethertype coming on a hard
+ * interface */
+int batman_skb_recv(struct sk_buff *skb, struct net_device *dev,
+	struct packet_type *ptype, struct net_device *orig_dev)
+{
+	struct bat_priv *bat_priv;
+	struct batman_packet *batman_packet;
+	struct batman_if *batman_if;
+	int ret;
+
+	batman_if = container_of(ptype, struct batman_if, batman_adv_ptype);
+	skb = skb_share_check(skb, GFP_ATOMIC);
+
+	/* skb was released by skb_share_check() */
+	if (!skb)
+		goto err_out;
+
+	/* packet should hold at least type and version */
+	if (unlikely(!pskb_may_pull(skb, 2)))
+		goto err_free;
+
+	/* expect a valid ethernet header here. */
+	if (unlikely(skb->mac_len != sizeof(struct ethhdr)
+				|| !skb_mac_header(skb)))
+		goto err_free;
+
+	if (!batman_if->soft_iface)
+		goto err_free;
+
+	bat_priv = netdev_priv(batman_if->soft_iface);
+
+	if (atomic_read(&bat_priv->mesh_state) != MESH_ACTIVE)
+		goto err_free;
+
+	/* discard frames on not active interfaces */
+	if (batman_if->if_status != IF_ACTIVE)
+		goto err_free;
+
+	batman_packet = (struct batman_packet *)skb->data;
+
+	if (batman_packet->version != COMPAT_VERSION) {
+		bat_dbg(DBG_BATMAN, bat_priv,
+			"Drop packet: incompatible batman version (%i)\n",
+			batman_packet->version);
+		goto err_free;
+	}
+
+	/* all receive handlers return whether they received or reused
+	 * the supplied skb. if not, we have to free the skb. */
+
+	switch (batman_packet->packet_type) {
+		/* batman originator packet */
+	case BAT_PACKET:
+		ret = recv_bat_packet(skb, batman_if);
+		break;
+
+		/* batman icmp packet */
+	case BAT_ICMP:
+		ret = recv_icmp_packet(skb, batman_if);
+		break;
+
+		/* unicast packet */
+	case BAT_UNICAST:
+		ret = recv_unicast_packet(skb, batman_if);
+		break;
+
+		/* fragmented unicast packet */
+	case BAT_UNICAST_FRAG:
+		ret = recv_ucast_frag_packet(skb, batman_if);
+		break;
+
+		/* broadcast packet */
+	case BAT_BCAST:
+		ret = recv_bcast_packet(skb, batman_if);
+		break;
+
+		/* vis packet */
+	case BAT_VIS:
+		ret = recv_vis_packet(skb, batman_if);
+		break;
+	default:
+		ret = NET_RX_DROP;
+	}
+
+	if (ret == NET_RX_DROP)
+		kfree_skb(skb);
+
+	/* return NET_RX_SUCCESS in any case as we
+	 * most probably dropped the packet for
+	 * routing-logical reasons. */
+
+	return NET_RX_SUCCESS;
+
+err_free:
+	kfree_skb(skb);
+err_out:
+	return NET_RX_DROP;
+}
+
+struct notifier_block hard_if_notifier = {
+	.notifier_call = hard_if_event,
+};