Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input

[linux-btrfs-devel.git] / net / batman-adv / soft-interface.c

/*
 * Copyright (C) 2007-2011 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 "soft-interface.h"
#include "hard-interface.h"
#include "routing.h"
#include "send.h"
#include "bat_debugfs.h"
#include "translation-table.h"
#include "hash.h"
#include "gateway_common.h"
#include "gateway_client.h"
#include "bat_sysfs.h"
#include "originator.h"
#include <linux/slab.h>
#include <linux/ethtool.h>
#include <linux/etherdevice.h>
#include <linux/if_vlan.h>
#include "unicast.h"


static int bat_get_settings(struct net_device *dev, struct ethtool_cmd *cmd);
static void bat_get_drvinfo(struct net_device *dev,
                            struct ethtool_drvinfo *info);
static u32 bat_get_msglevel(struct net_device *dev);
static void bat_set_msglevel(struct net_device *dev, u32 value);
static u32 bat_get_link(struct net_device *dev);

static const struct ethtool_ops bat_ethtool_ops = {
        .get_settings = bat_get_settings,
        .get_drvinfo = bat_get_drvinfo,
        .get_msglevel = bat_get_msglevel,
        .set_msglevel = bat_set_msglevel,
        .get_link = bat_get_link,
};

int my_skb_head_push(struct sk_buff *skb, unsigned int len)
{
        int result;

        /**
         * TODO: We must check if we can release all references to non-payload
         * data using skb_header_release in our skbs to allow skb_cow_header to
         * work optimally. This means that those skbs are not allowed to read
         * or write any data which is before the current position of skb->data
         * after that call and thus allow other skbs with the same data buffer
         * to write freely in that area.
         */
        result = skb_cow_head(skb, len);
        if (result < 0)
                return result;

        skb_push(skb, len);
        return 0;
}

static void softif_neigh_free_ref(struct softif_neigh *softif_neigh)
{
        if (atomic_dec_and_test(&softif_neigh->refcount))
                kfree_rcu(softif_neigh, rcu);
}

static void softif_neigh_vid_free_rcu(struct rcu_head *rcu)
{
        struct softif_neigh_vid *softif_neigh_vid;
        struct softif_neigh *softif_neigh;
        struct hlist_node *node, *node_tmp;
        struct bat_priv *bat_priv;

        softif_neigh_vid = container_of(rcu, struct softif_neigh_vid, rcu);
        bat_priv = softif_neigh_vid->bat_priv;

        spin_lock_bh(&bat_priv->softif_neigh_lock);
        hlist_for_each_entry_safe(softif_neigh, node, node_tmp,
                                  &softif_neigh_vid->softif_neigh_list, list) {
                hlist_del_rcu(&softif_neigh->list);
                softif_neigh_free_ref(softif_neigh);
        }
        spin_unlock_bh(&bat_priv->softif_neigh_lock);

        kfree(softif_neigh_vid);
}

static void softif_neigh_vid_free_ref(struct softif_neigh_vid *softif_neigh_vid)
{
        if (atomic_dec_and_test(&softif_neigh_vid->refcount))
                call_rcu(&softif_neigh_vid->rcu, softif_neigh_vid_free_rcu);
}

static struct softif_neigh_vid *softif_neigh_vid_get(struct bat_priv *bat_priv,
                                                     short vid)
{
        struct softif_neigh_vid *softif_neigh_vid;
        struct hlist_node *node;

        rcu_read_lock();
        hlist_for_each_entry_rcu(softif_neigh_vid, node,
                                 &bat_priv->softif_neigh_vids, list) {
                if (softif_neigh_vid->vid != vid)
                        continue;

                if (!atomic_inc_not_zero(&softif_neigh_vid->refcount))
                        continue;

                goto out;
        }

        softif_neigh_vid = kzalloc(sizeof(*softif_neigh_vid), GFP_ATOMIC);
        if (!softif_neigh_vid)
                goto out;

        softif_neigh_vid->vid = vid;
        softif_neigh_vid->bat_priv = bat_priv;

        /* initialize with 2 - caller decrements counter by one */
        atomic_set(&softif_neigh_vid->refcount, 2);
        INIT_HLIST_HEAD(&softif_neigh_vid->softif_neigh_list);
        INIT_HLIST_NODE(&softif_neigh_vid->list);
        spin_lock_bh(&bat_priv->softif_neigh_vid_lock);
        hlist_add_head_rcu(&softif_neigh_vid->list,
                           &bat_priv->softif_neigh_vids);
        spin_unlock_bh(&bat_priv->softif_neigh_vid_lock);

out:
        rcu_read_unlock();
        return softif_neigh_vid;
}

static struct softif_neigh *softif_neigh_get(struct bat_priv *bat_priv,
                                             const uint8_t *addr, short vid)
{
        struct softif_neigh_vid *softif_neigh_vid;
        struct softif_neigh *softif_neigh = NULL;
        struct hlist_node *node;

        softif_neigh_vid = softif_neigh_vid_get(bat_priv, vid);
        if (!softif_neigh_vid)
                goto out;

        rcu_read_lock();
        hlist_for_each_entry_rcu(softif_neigh, node,
                                 &softif_neigh_vid->softif_neigh_list,
                                 list) {
                if (!compare_eth(softif_neigh->addr, addr))
                        continue;

                if (!atomic_inc_not_zero(&softif_neigh->refcount))
                        continue;

                softif_neigh->last_seen = jiffies;
                goto unlock;
        }

        softif_neigh = kzalloc(sizeof(*softif_neigh), GFP_ATOMIC);
        if (!softif_neigh)
                goto unlock;

        memcpy(softif_neigh->addr, addr, ETH_ALEN);
        softif_neigh->last_seen = jiffies;
        /* initialize with 2 - caller decrements counter by one */
        atomic_set(&softif_neigh->refcount, 2);

        INIT_HLIST_NODE(&softif_neigh->list);
        spin_lock_bh(&bat_priv->softif_neigh_lock);
        hlist_add_head_rcu(&softif_neigh->list,
                           &softif_neigh_vid->softif_neigh_list);
        spin_unlock_bh(&bat_priv->softif_neigh_lock);

unlock:
        rcu_read_unlock();
out:
        if (softif_neigh_vid)
                softif_neigh_vid_free_ref(softif_neigh_vid);
        return softif_neigh;
}

static struct softif_neigh *softif_neigh_get_selected(
                                struct softif_neigh_vid *softif_neigh_vid)
{
        struct softif_neigh *softif_neigh;

        rcu_read_lock();
        softif_neigh = rcu_dereference(softif_neigh_vid->softif_neigh);

        if (softif_neigh && !atomic_inc_not_zero(&softif_neigh->refcount))
                softif_neigh = NULL;

        rcu_read_unlock();
        return softif_neigh;
}

static struct softif_neigh *softif_neigh_vid_get_selected(
                                                struct bat_priv *bat_priv,
                                                short vid)
{
        struct softif_neigh_vid *softif_neigh_vid;
        struct softif_neigh *softif_neigh = NULL;

        softif_neigh_vid = softif_neigh_vid_get(bat_priv, vid);
        if (!softif_neigh_vid)
                goto out;

        softif_neigh = softif_neigh_get_selected(softif_neigh_vid);
out:
        if (softif_neigh_vid)
                softif_neigh_vid_free_ref(softif_neigh_vid);
        return softif_neigh;
}

static void softif_neigh_vid_select(struct bat_priv *bat_priv,
                                    struct softif_neigh *new_neigh,
                                    short vid)
{
        struct softif_neigh_vid *softif_neigh_vid;
        struct softif_neigh *curr_neigh;

        softif_neigh_vid = softif_neigh_vid_get(bat_priv, vid);
        if (!softif_neigh_vid)
                goto out;

        spin_lock_bh(&bat_priv->softif_neigh_lock);

        if (new_neigh && !atomic_inc_not_zero(&new_neigh->refcount))
                new_neigh = NULL;

        curr_neigh = rcu_dereference_protected(softif_neigh_vid->softif_neigh,
                                               1);
        rcu_assign_pointer(softif_neigh_vid->softif_neigh, new_neigh);

        if ((curr_neigh) && (!new_neigh))
                bat_dbg(DBG_ROUTES, bat_priv,
                        "Removing mesh exit point on vid: %d (prev: %pM).\n",
                        vid, curr_neigh->addr);
        else if ((curr_neigh) && (new_neigh))
                bat_dbg(DBG_ROUTES, bat_priv,
                        "Changing mesh exit point on vid: %d from %pM "
                        "to %pM.\n", vid, curr_neigh->addr, new_neigh->addr);
        else if ((!curr_neigh) && (new_neigh))
                bat_dbg(DBG_ROUTES, bat_priv,
                        "Setting mesh exit point on vid: %d to %pM.\n",
                        vid, new_neigh->addr);

        if (curr_neigh)
                softif_neigh_free_ref(curr_neigh);

        spin_unlock_bh(&bat_priv->softif_neigh_lock);

out:
        if (softif_neigh_vid)
                softif_neigh_vid_free_ref(softif_neigh_vid);
}

static void softif_neigh_vid_deselect(struct bat_priv *bat_priv,
                                      struct softif_neigh_vid *softif_neigh_vid)
{
        struct softif_neigh *curr_neigh;
        struct softif_neigh *softif_neigh = NULL, *softif_neigh_tmp;
        struct hard_iface *primary_if = NULL;
        struct hlist_node *node;

        primary_if = primary_if_get_selected(bat_priv);
        if (!primary_if)
                goto out;

        /* find new softif_neigh immediately to avoid temporary loops */
        rcu_read_lock();
        curr_neigh = rcu_dereference(softif_neigh_vid->softif_neigh);

        hlist_for_each_entry_rcu(softif_neigh_tmp, node,
                                 &softif_neigh_vid->softif_neigh_list,
                                 list) {
                if (softif_neigh_tmp == curr_neigh)
                        continue;

                /* we got a neighbor but its mac is 'bigger' than ours  */
                if (memcmp(primary_if->net_dev->dev_addr,
                           softif_neigh_tmp->addr, ETH_ALEN) < 0)
                        continue;

                if (!atomic_inc_not_zero(&softif_neigh_tmp->refcount))
                        continue;

                softif_neigh = softif_neigh_tmp;
                goto unlock;
        }

unlock:
        rcu_read_unlock();
out:
        softif_neigh_vid_select(bat_priv, softif_neigh, softif_neigh_vid->vid);

        if (primary_if)
                hardif_free_ref(primary_if);
        if (softif_neigh)
                softif_neigh_free_ref(softif_neigh);
}

int softif_neigh_seq_print_text(struct seq_file *seq, void *offset)
{
        struct net_device *net_dev = (struct net_device *)seq->private;
        struct bat_priv *bat_priv = netdev_priv(net_dev);
        struct softif_neigh_vid *softif_neigh_vid;
        struct softif_neigh *softif_neigh;
        struct hard_iface *primary_if;
        struct hlist_node *node, *node_tmp;
        struct softif_neigh *curr_softif_neigh;
        int ret = 0, last_seen_secs, last_seen_msecs;

        primary_if = primary_if_get_selected(bat_priv);
        if (!primary_if) {
                ret = seq_printf(seq, "BATMAN mesh %s disabled - "
                                 "please specify interfaces to enable it\n",
                                 net_dev->name);
                goto out;
        }

        if (primary_if->if_status != IF_ACTIVE) {
                ret = seq_printf(seq, "BATMAN mesh %s "
                                 "disabled - primary interface not active\n",
                                 net_dev->name);
                goto out;
        }

        seq_printf(seq, "Softif neighbor list (%s)\n", net_dev->name);

        rcu_read_lock();
        hlist_for_each_entry_rcu(softif_neigh_vid, node,
                                 &bat_priv->softif_neigh_vids, list) {
                seq_printf(seq, "     %-15s %s on vid: %d\n",
                           "Originator", "last-seen", softif_neigh_vid->vid);

                curr_softif_neigh = softif_neigh_get_selected(softif_neigh_vid);

                hlist_for_each_entry_rcu(softif_neigh, node_tmp,
                                         &softif_neigh_vid->softif_neigh_list,
                                         list) {
                        last_seen_secs = jiffies_to_msecs(jiffies -
                                                softif_neigh->last_seen) / 1000;
                        last_seen_msecs = jiffies_to_msecs(jiffies -
                                                softif_neigh->last_seen) % 1000;
                        seq_printf(seq, "%s %pM  %3i.%03is\n",
                                   curr_softif_neigh == softif_neigh
                                   ? "=>" : "  ", softif_neigh->addr,
                                   last_seen_secs, last_seen_msecs);
                }

                if (curr_softif_neigh)
                        softif_neigh_free_ref(curr_softif_neigh);

                seq_printf(seq, "\n");
        }
        rcu_read_unlock();

out:
        if (primary_if)
                hardif_free_ref(primary_if);
        return ret;
}

void softif_neigh_purge(struct bat_priv *bat_priv)
{
        struct softif_neigh *softif_neigh, *curr_softif_neigh;
        struct softif_neigh_vid *softif_neigh_vid;
        struct hlist_node *node, *node_tmp, *node_tmp2;
        int do_deselect;

        rcu_read_lock();
        hlist_for_each_entry_rcu(softif_neigh_vid, node,
                                 &bat_priv->softif_neigh_vids, list) {
                if (!atomic_inc_not_zero(&softif_neigh_vid->refcount))
                        continue;

                curr_softif_neigh = softif_neigh_get_selected(softif_neigh_vid);
                do_deselect = 0;

                spin_lock_bh(&bat_priv->softif_neigh_lock);
                hlist_for_each_entry_safe(softif_neigh, node_tmp, node_tmp2,
                                          &softif_neigh_vid->softif_neigh_list,
                                          list) {
                        if ((!time_after(jiffies, softif_neigh->last_seen +
                                msecs_to_jiffies(SOFTIF_NEIGH_TIMEOUT))) &&
                            (atomic_read(&bat_priv->mesh_state) == MESH_ACTIVE))
                                continue;

                        if (curr_softif_neigh == softif_neigh) {
                                bat_dbg(DBG_ROUTES, bat_priv,
                                        "Current mesh exit point on vid: %d "
                                        "'%pM' vanished.\n",
                                        softif_neigh_vid->vid,
                                        softif_neigh->addr);
                                do_deselect = 1;
                        }

                        hlist_del_rcu(&softif_neigh->list);
                        softif_neigh_free_ref(softif_neigh);
                }
                spin_unlock_bh(&bat_priv->softif_neigh_lock);

                /* soft_neigh_vid_deselect() needs to acquire the
                 * softif_neigh_lock */
                if (do_deselect)
                        softif_neigh_vid_deselect(bat_priv, softif_neigh_vid);

                if (curr_softif_neigh)
                        softif_neigh_free_ref(curr_softif_neigh);

                softif_neigh_vid_free_ref(softif_neigh_vid);
        }
        rcu_read_unlock();

        spin_lock_bh(&bat_priv->softif_neigh_vid_lock);
        hlist_for_each_entry_safe(softif_neigh_vid, node, node_tmp,
                                  &bat_priv->softif_neigh_vids, list) {
                if (!hlist_empty(&softif_neigh_vid->softif_neigh_list))
                        continue;

                hlist_del_rcu(&softif_neigh_vid->list);
                softif_neigh_vid_free_ref(softif_neigh_vid);
        }
        spin_unlock_bh(&bat_priv->softif_neigh_vid_lock);

}

static void softif_batman_recv(struct sk_buff *skb, struct net_device *dev,
                               short vid)
{
        struct bat_priv *bat_priv = netdev_priv(dev);
        struct ethhdr *ethhdr = (struct ethhdr *)skb->data;
        struct batman_ogm_packet *batman_ogm_packet;
        struct softif_neigh *softif_neigh = NULL;
        struct hard_iface *primary_if = NULL;
        struct softif_neigh *curr_softif_neigh = NULL;

        if (ntohs(ethhdr->h_proto) == ETH_P_8021Q)
                batman_ogm_packet = (struct batman_ogm_packet *)
                                        (skb->data + ETH_HLEN + VLAN_HLEN);
        else
                batman_ogm_packet = (struct batman_ogm_packet *)
                                                        (skb->data + ETH_HLEN);

        if (batman_ogm_packet->version != COMPAT_VERSION)
                goto out;

        if (batman_ogm_packet->packet_type != BAT_OGM)
                goto out;

        if (!(batman_ogm_packet->flags & PRIMARIES_FIRST_HOP))
                goto out;

        if (is_my_mac(batman_ogm_packet->orig))
                goto out;

        softif_neigh = softif_neigh_get(bat_priv, batman_ogm_packet->orig, vid);
        if (!softif_neigh)
                goto out;

        curr_softif_neigh = softif_neigh_vid_get_selected(bat_priv, vid);
        if (curr_softif_neigh == softif_neigh)
                goto out;

        primary_if = primary_if_get_selected(bat_priv);
        if (!primary_if)
                goto out;

        /* we got a neighbor but its mac is 'bigger' than ours  */
        if (memcmp(primary_if->net_dev->dev_addr,
                   softif_neigh->addr, ETH_ALEN) < 0)
                goto out;

        /* close own batX device and use softif_neigh as exit node */
        if (!curr_softif_neigh) {
                softif_neigh_vid_select(bat_priv, softif_neigh, vid);
                goto out;
        }

        /* switch to new 'smallest neighbor' */
        if (memcmp(softif_neigh->addr, curr_softif_neigh->addr, ETH_ALEN) < 0)
                softif_neigh_vid_select(bat_priv, softif_neigh, vid);

out:
        kfree_skb(skb);
        if (softif_neigh)
                softif_neigh_free_ref(softif_neigh);
        if (curr_softif_neigh)
                softif_neigh_free_ref(curr_softif_neigh);
        if (primary_if)
                hardif_free_ref(primary_if);
        return;
}

static int interface_open(struct net_device *dev)
{
        netif_start_queue(dev);
        return 0;
}

static int interface_release(struct net_device *dev)
{
        netif_stop_queue(dev);
        return 0;
}

static struct net_device_stats *interface_stats(struct net_device *dev)
{
        struct bat_priv *bat_priv = netdev_priv(dev);
        return &bat_priv->stats;
}

static int interface_set_mac_addr(struct net_device *dev, void *p)
{
        struct bat_priv *bat_priv = netdev_priv(dev);
        struct sockaddr *addr = p;

        if (!is_valid_ether_addr(addr->sa_data))
                return -EADDRNOTAVAIL;

        /* only modify transtable if it has been initialized before */
        if (atomic_read(&bat_priv->mesh_state) == MESH_ACTIVE) {
                tt_local_remove(bat_priv, dev->dev_addr,
                                "mac address changed", false);
                tt_local_add(dev, addr->sa_data, NULL_IFINDEX);
        }

        memcpy(dev->dev_addr, addr->sa_data, ETH_ALEN);
        return 0;
}

static int interface_change_mtu(struct net_device *dev, int new_mtu)
{
        /* check ranges */
        if ((new_mtu < 68) || (new_mtu > hardif_min_mtu(dev)))
                return -EINVAL;

        dev->mtu = new_mtu;

        return 0;
}

static int interface_tx(struct sk_buff *skb, struct net_device *soft_iface)
{
        struct ethhdr *ethhdr = (struct ethhdr *)skb->data;
        struct bat_priv *bat_priv = netdev_priv(soft_iface);
        struct hard_iface *primary_if = NULL;
        struct bcast_packet *bcast_packet;
        struct vlan_ethhdr *vhdr;
        struct softif_neigh *curr_softif_neigh = NULL;
        struct orig_node *orig_node = NULL;
        int data_len = skb->len, ret;
        short vid = -1;
        bool do_bcast;

        if (atomic_read(&bat_priv->mesh_state) != MESH_ACTIVE)
                goto dropped;

        soft_iface->trans_start = jiffies;

        switch (ntohs(ethhdr->h_proto)) {
        case ETH_P_8021Q:
                vhdr = (struct vlan_ethhdr *)skb->data;
                vid = ntohs(vhdr->h_vlan_TCI) & VLAN_VID_MASK;

                if (ntohs(vhdr->h_vlan_encapsulated_proto) != ETH_P_BATMAN)
                        break;

                /* fall through */
        case ETH_P_BATMAN:
                softif_batman_recv(skb, soft_iface, vid);
                goto end;
        }

        /**
         * if we have a another chosen mesh exit node in range
         * it will transport the packets to the mesh
         */
        curr_softif_neigh = softif_neigh_vid_get_selected(bat_priv, vid);
        if (curr_softif_neigh)
                goto dropped;

        /* Register the client MAC in the transtable */
        tt_local_add(soft_iface, ethhdr->h_source, skb->skb_iif);

        orig_node = transtable_search(bat_priv, ethhdr->h_source,
                                      ethhdr->h_dest);
        do_bcast = is_multicast_ether_addr(ethhdr->h_dest);
        if (do_bcast || (orig_node && orig_node->gw_flags)) {
                ret = gw_is_target(bat_priv, skb, orig_node);

                if (ret < 0)
                        goto dropped;

                if (ret)
                        do_bcast = false;
        }

        /* ethernet packet should be broadcasted */
        if (do_bcast) {
                primary_if = primary_if_get_selected(bat_priv);
                if (!primary_if)
                        goto dropped;

                if (my_skb_head_push(skb, sizeof(*bcast_packet)) < 0)
                        goto dropped;

                bcast_packet = (struct bcast_packet *)skb->data;
                bcast_packet->version = COMPAT_VERSION;
                bcast_packet->ttl = TTL;

                /* batman packet type: broadcast */
                bcast_packet->packet_type = BAT_BCAST;

                /* hw address of first interface is the orig mac because only
                 * this mac is known throughout the mesh */
                memcpy(bcast_packet->orig,
                       primary_if->net_dev->dev_addr, ETH_ALEN);

                /* set broadcast sequence number */
                bcast_packet->seqno =
                        htonl(atomic_inc_return(&bat_priv->bcast_seqno));

                add_bcast_packet_to_list(bat_priv, skb, 1);

                /* a copy is stored in the bcast list, therefore removing
                 * the original skb. */
                kfree_skb(skb);

        /* unicast packet */
        } else {
                ret = unicast_send_skb(skb, bat_priv);
                if (ret != 0)
                        goto dropped_freed;
        }

        bat_priv->stats.tx_packets++;
        bat_priv->stats.tx_bytes += data_len;
        goto end;

dropped:
        kfree_skb(skb);
dropped_freed:
        bat_priv->stats.tx_dropped++;
end:
        if (curr_softif_neigh)
                softif_neigh_free_ref(curr_softif_neigh);
        if (primary_if)
                hardif_free_ref(primary_if);
        if (orig_node)
                orig_node_free_ref(orig_node);
        return NETDEV_TX_OK;
}

void interface_rx(struct net_device *soft_iface,
                  struct sk_buff *skb, struct hard_iface *recv_if,
                  int hdr_size)
{
        struct bat_priv *bat_priv = netdev_priv(soft_iface);
        struct unicast_packet *unicast_packet;
        struct ethhdr *ethhdr;
        struct vlan_ethhdr *vhdr;
        struct softif_neigh *curr_softif_neigh = NULL;
        short vid = -1;
        int ret;

        /* check if enough space is available for pulling, and pull */
        if (!pskb_may_pull(skb, hdr_size))
                goto dropped;

        skb_pull_rcsum(skb, hdr_size);
        skb_reset_mac_header(skb);

        ethhdr = (struct ethhdr *)skb_mac_header(skb);

        switch (ntohs(ethhdr->h_proto)) {
        case ETH_P_8021Q:
                vhdr = (struct vlan_ethhdr *)skb->data;
                vid = ntohs(vhdr->h_vlan_TCI) & VLAN_VID_MASK;

                if (ntohs(vhdr->h_vlan_encapsulated_proto) != ETH_P_BATMAN)
                        break;

                /* fall through */
        case ETH_P_BATMAN:
                goto dropped;
        }

        /**
         * if we have a another chosen mesh exit node in range
         * it will transport the packets to the non-mesh network
         */
        curr_softif_neigh = softif_neigh_vid_get_selected(bat_priv, vid);
        if (curr_softif_neigh) {
                skb_push(skb, hdr_size);
                unicast_packet = (struct unicast_packet *)skb->data;

                if ((unicast_packet->packet_type != BAT_UNICAST) &&
                    (unicast_packet->packet_type != BAT_UNICAST_FRAG))
                        goto dropped;

                skb_reset_mac_header(skb);

                memcpy(unicast_packet->dest,
                       curr_softif_neigh->addr, ETH_ALEN);
                ret = route_unicast_packet(skb, recv_if);
                if (ret == NET_RX_DROP)
                        goto dropped;

                goto out;
        }

        /* skb->dev & skb->pkt_type are set here */
        if (unlikely(!pskb_may_pull(skb, ETH_HLEN)))
                goto dropped;
        skb->protocol = eth_type_trans(skb, soft_iface);

        /* should not be necessary anymore as we use skb_pull_rcsum()
         * TODO: please verify this and remove this TODO
         * -- Dec 21st 2009, Simon Wunderlich */

/*      skb->ip_summed = CHECKSUM_UNNECESSARY;*/

        bat_priv->stats.rx_packets++;
        bat_priv->stats.rx_bytes += skb->len + sizeof(struct ethhdr);

        soft_iface->last_rx = jiffies;

        if (is_ap_isolated(bat_priv, ethhdr->h_source, ethhdr->h_dest))
                goto dropped;

        netif_rx(skb);
        goto out;

dropped:
        kfree_skb(skb);
out:
        if (curr_softif_neigh)
                softif_neigh_free_ref(curr_softif_neigh);
        return;
}

static const struct net_device_ops bat_netdev_ops = {
        .ndo_open = interface_open,
        .ndo_stop = interface_release,
        .ndo_get_stats = interface_stats,
        .ndo_set_mac_address = interface_set_mac_addr,
        .ndo_change_mtu = interface_change_mtu,
        .ndo_start_xmit = interface_tx,
        .ndo_validate_addr = eth_validate_addr
};

static void interface_setup(struct net_device *dev)
{
        struct bat_priv *priv = netdev_priv(dev);
        char dev_addr[ETH_ALEN];

        ether_setup(dev);

        dev->netdev_ops = &bat_netdev_ops;
        dev->destructor = free_netdev;
        dev->tx_queue_len = 0;

        /**
         * can't call min_mtu, because the needed variables
         * have not been initialized yet
         */
        dev->mtu = ETH_DATA_LEN;
        /* reserve more space in the skbuff for our header */
        dev->hard_header_len = BAT_HEADER_LEN;

        /* generate random address */
        random_ether_addr(dev_addr);
        memcpy(dev->dev_addr, dev_addr, ETH_ALEN);

        SET_ETHTOOL_OPS(dev, &bat_ethtool_ops);

        memset(priv, 0, sizeof(*priv));
}

struct net_device *softif_create(const char *name)
{
        struct net_device *soft_iface;
        struct bat_priv *bat_priv;
        int ret;

        soft_iface = alloc_netdev(sizeof(*bat_priv), name, interface_setup);

        if (!soft_iface)
                goto out;

        ret = register_netdevice(soft_iface);
        if (ret < 0) {
                pr_err("Unable to register the batman interface '%s': %i\n",
                       name, ret);
                goto free_soft_iface;
        }

        bat_priv = netdev_priv(soft_iface);

        atomic_set(&bat_priv->aggregated_ogms, 1);
        atomic_set(&bat_priv->bonding, 0);
        atomic_set(&bat_priv->ap_isolation, 0);
        atomic_set(&bat_priv->vis_mode, VIS_TYPE_CLIENT_UPDATE);
        atomic_set(&bat_priv->gw_mode, GW_MODE_OFF);
        atomic_set(&bat_priv->gw_sel_class, 20);
        atomic_set(&bat_priv->gw_bandwidth, 41);
        atomic_set(&bat_priv->orig_interval, 1000);
        atomic_set(&bat_priv->hop_penalty, 10);
        atomic_set(&bat_priv->log_level, 0);
        atomic_set(&bat_priv->fragmentation, 1);
        atomic_set(&bat_priv->bcast_queue_left, BCAST_QUEUE_LEN);
        atomic_set(&bat_priv->batman_queue_left, BATMAN_QUEUE_LEN);

        atomic_set(&bat_priv->mesh_state, MESH_INACTIVE);
        atomic_set(&bat_priv->bcast_seqno, 1);
        atomic_set(&bat_priv->ttvn, 0);
        atomic_set(&bat_priv->tt_local_changes, 0);
        atomic_set(&bat_priv->tt_ogm_append_cnt, 0);

        bat_priv->tt_buff = NULL;
        bat_priv->tt_buff_len = 0;
        bat_priv->tt_poss_change = false;

        bat_priv->primary_if = NULL;
        bat_priv->num_ifaces = 0;

        ret = sysfs_add_meshif(soft_iface);
        if (ret < 0)
                goto unreg_soft_iface;

        ret = debugfs_add_meshif(soft_iface);
        if (ret < 0)
                goto unreg_sysfs;

        ret = mesh_init(soft_iface);
        if (ret < 0)
                goto unreg_debugfs;

        return soft_iface;

unreg_debugfs:
        debugfs_del_meshif(soft_iface);
unreg_sysfs:
        sysfs_del_meshif(soft_iface);
unreg_soft_iface:
        unregister_netdev(soft_iface);
        return NULL;

free_soft_iface:
        free_netdev(soft_iface);
out:
        return NULL;
}

void softif_destroy(struct net_device *soft_iface)
{
        debugfs_del_meshif(soft_iface);
        sysfs_del_meshif(soft_iface);
        mesh_free(soft_iface);
        unregister_netdevice(soft_iface);
}

int softif_is_valid(const struct net_device *net_dev)
{
        if (net_dev->netdev_ops->ndo_start_xmit == interface_tx)
                return 1;

        return 0;
}

/* ethtool */
static int bat_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
{
        cmd->supported = 0;
        cmd->advertising = 0;
        ethtool_cmd_speed_set(cmd, SPEED_10);
        cmd->duplex = DUPLEX_FULL;
        cmd->port = PORT_TP;
        cmd->phy_address = 0;
        cmd->transceiver = XCVR_INTERNAL;
        cmd->autoneg = AUTONEG_DISABLE;
        cmd->maxtxpkt = 0;
        cmd->maxrxpkt = 0;

        return 0;
}

static void bat_get_drvinfo(struct net_device *dev,
                            struct ethtool_drvinfo *info)
{
        strcpy(info->driver, "B.A.T.M.A.N. advanced");
        strcpy(info->version, SOURCE_VERSION);
        strcpy(info->fw_version, "N/A");
        strcpy(info->bus_info, "batman");
}

static u32 bat_get_msglevel(struct net_device *dev)
{
        return -EOPNOTSUPP;
}

static void bat_set_msglevel(struct net_device *dev, u32 value)
{
}

static u32 bat_get_link(struct net_device *dev)
{
        return 1;
}