hard-interface.c

Go to the documentation of this file.

/* Copyright (C) 2007-2012 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 "sysfs.h"
#include "originator.h"
#include "hash.h"
#include "bridge_loop_avoidance.h"

#include <linux/if_arp.h>

void batadv_hardif_free_rcu(struct rcu_head *rcu)
{
    struct batadv_hard_iface *hard_iface;

    hard_iface = container_of(rcu, struct batadv_hard_iface, rcu);
    dev_put(hard_iface->net_dev);
    kfree(hard_iface);
}

struct batadv_hard_iface *
batadv_hardif_get_by_netdev(const struct net_device *net_dev)
{
    struct batadv_hard_iface *hard_iface;

    rcu_read_lock();
    list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
        if (hard_iface->net_dev == net_dev &&
            atomic_inc_not_zero(&hard_iface->refcount))
            goto out;
    }

    hard_iface = NULL;

out:
    rcu_read_unlock();
    return hard_iface;
}

static int batadv_is_valid_iface(const 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 */
    if (batadv_softif_is_valid(net_dev))
        return 0;

    return 1;
}

static struct batadv_hard_iface *
batadv_hardif_get_active(const struct net_device *soft_iface)
{
    struct batadv_hard_iface *hard_iface;

    rcu_read_lock();
    list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
        if (hard_iface->soft_iface != soft_iface)
            continue;

        if (hard_iface->if_status == BATADV_IF_ACTIVE &&
            atomic_inc_not_zero(&hard_iface->refcount))
            goto out;
    }

    hard_iface = NULL;

out:
    rcu_read_unlock();
    return hard_iface;
}

static void batadv_primary_if_update_addr(struct batadv_priv *bat_priv,
                      struct batadv_hard_iface *oldif)
{
    struct batadv_vis_packet *vis_packet;
    struct batadv_hard_iface *primary_if;
    struct sk_buff *skb;

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

    skb = bat_priv->vis.my_info->skb_packet;
    vis_packet = (struct batadv_vis_packet *)skb->data;
    memcpy(vis_packet->vis_orig, primary_if->net_dev->dev_addr, ETH_ALEN);
    memcpy(vis_packet->sender_orig,
           primary_if->net_dev->dev_addr, ETH_ALEN);

    batadv_bla_update_orig_address(bat_priv, primary_if, oldif);
out:
    if (primary_if)
        batadv_hardif_free_ref(primary_if);
}

static void batadv_primary_if_select(struct batadv_priv *bat_priv,
                     struct batadv_hard_iface *new_hard_iface)
{
    struct batadv_hard_iface *curr_hard_iface;

    ASSERT_RTNL();

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

    curr_hard_iface = rcu_dereference_protected(bat_priv->primary_if, 1);
    rcu_assign_pointer(bat_priv->primary_if, new_hard_iface);

    if (!new_hard_iface)
        goto out;

    bat_priv->bat_algo_ops->bat_primary_iface_set(new_hard_iface);
    batadv_primary_if_update_addr(bat_priv, curr_hard_iface);

out:
    if (curr_hard_iface)
        batadv_hardif_free_ref(curr_hard_iface);
}

static bool
batadv_hardif_is_iface_up(const struct batadv_hard_iface *hard_iface)
{
    if (hard_iface->net_dev->flags & IFF_UP)
        return true;

    return false;
}

static void batadv_check_known_mac_addr(const struct net_device *net_dev)
{
    const struct batadv_hard_iface *hard_iface;

    rcu_read_lock();
    list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
        if ((hard_iface->if_status != BATADV_IF_ACTIVE) &&
            (hard_iface->if_status != BATADV_IF_TO_BE_ACTIVATED))
            continue;

        if (hard_iface->net_dev == net_dev)
            continue;

        if (!batadv_compare_eth(hard_iface->net_dev->dev_addr,
                    net_dev->dev_addr))
            continue;

        pr_warn("The newly added mac address (%pM) already exists on: %s\n",
            net_dev->dev_addr, hard_iface->net_dev->name);
        pr_warn("It is strongly recommended to keep mac addresses unique to avoid problems!\n");
    }
    rcu_read_unlock();
}

int batadv_hardif_min_mtu(struct net_device *soft_iface)
{
    const struct batadv_priv *bat_priv = netdev_priv(soft_iface);
    const struct batadv_hard_iface *hard_iface;
    /* 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(hard_iface, &batadv_hardif_list, list) {
        if ((hard_iface->if_status != BATADV_IF_ACTIVE) &&
            (hard_iface->if_status != BATADV_IF_TO_BE_ACTIVATED))
            continue;

        if (hard_iface->soft_iface != soft_iface)
            continue;

        min_mtu = min_t(int,
                hard_iface->net_dev->mtu - BATADV_HEADER_LEN,
                min_mtu);
    }
    rcu_read_unlock();
out:
    return min_mtu;
}

/* adjusts the MTU if a new interface with a smaller MTU appeared. */
void batadv_update_min_mtu(struct net_device *soft_iface)
{
    int min_mtu;

    min_mtu = batadv_hardif_min_mtu(soft_iface);
    if (soft_iface->mtu != min_mtu)
        soft_iface->mtu = min_mtu;
}

static void
batadv_hardif_activate_interface(struct batadv_hard_iface *hard_iface)
{
    struct batadv_priv *bat_priv;
    struct batadv_hard_iface *primary_if = NULL;

    if (hard_iface->if_status != BATADV_IF_INACTIVE)
        goto out;

    bat_priv = netdev_priv(hard_iface->soft_iface);

    bat_priv->bat_algo_ops->bat_iface_update_mac(hard_iface);
    hard_iface->if_status = BATADV_IF_TO_BE_ACTIVATED;

    /* the first active interface becomes our primary interface or
     * the next active interface after the old primary interface was removed
     */
    primary_if = batadv_primary_if_get_selected(bat_priv);
    if (!primary_if)
        batadv_primary_if_select(bat_priv, hard_iface);

    batadv_info(hard_iface->soft_iface, "Interface activated: %s\n",
            hard_iface->net_dev->name);

    batadv_update_min_mtu(hard_iface->soft_iface);

out:
    if (primary_if)
        batadv_hardif_free_ref(primary_if);
}

static void
batadv_hardif_deactivate_interface(struct batadv_hard_iface *hard_iface)
{
    if ((hard_iface->if_status != BATADV_IF_ACTIVE) &&
        (hard_iface->if_status != BATADV_IF_TO_BE_ACTIVATED))
        return;

    hard_iface->if_status = BATADV_IF_INACTIVE;

    batadv_info(hard_iface->soft_iface, "Interface deactivated: %s\n",
            hard_iface->net_dev->name);

    batadv_update_min_mtu(hard_iface->soft_iface);
}

int batadv_hardif_enable_interface(struct batadv_hard_iface *hard_iface,
                   const char *iface_name)
{
    struct batadv_priv *bat_priv;
    struct net_device *soft_iface;
    __be16 ethertype = __constant_htons(BATADV_ETH_P_BATMAN);
    int ret;

    if (hard_iface->if_status != BATADV_IF_NOT_IN_USE)
        goto out;

    if (!atomic_inc_not_zero(&hard_iface->refcount))
        goto out;

    /* hard-interface is part of a bridge */
    if (hard_iface->net_dev->priv_flags & IFF_BRIDGE_PORT)
        pr_err("You are about to enable batman-adv on '%s' which already is part of a bridge. Unless you know exactly what you are doing this is probably wrong and won't work the way you think it would.\n",
               hard_iface->net_dev->name);

    soft_iface = dev_get_by_name(&init_net, iface_name);

    if (!soft_iface) {
        soft_iface = batadv_softif_create(iface_name);

        if (!soft_iface) {
            ret = -ENOMEM;
            goto err;
        }

        /* dev_get_by_name() increases the reference counter for us */
        dev_hold(soft_iface);
    }

    if (!batadv_softif_is_valid(soft_iface)) {
        pr_err("Can't create batman mesh interface %s: already exists as regular interface\n",
               soft_iface->name);
        ret = -EINVAL;
        goto err_dev;
    }

    hard_iface->soft_iface = soft_iface;
    bat_priv = netdev_priv(hard_iface->soft_iface);

    ret = bat_priv->bat_algo_ops->bat_iface_enable(hard_iface);
    if (ret < 0)
        goto err_dev;

    hard_iface->if_num = bat_priv->num_ifaces;
    bat_priv->num_ifaces++;
    hard_iface->if_status = BATADV_IF_INACTIVE;
    ret = batadv_orig_hash_add_if(hard_iface, bat_priv->num_ifaces);
    if (ret < 0) {
        bat_priv->bat_algo_ops->bat_iface_disable(hard_iface);
        bat_priv->num_ifaces--;
        hard_iface->if_status = BATADV_IF_NOT_IN_USE;
        goto err_dev;
    }

    hard_iface->batman_adv_ptype.type = ethertype;
    hard_iface->batman_adv_ptype.func = batadv_batman_skb_recv;
    hard_iface->batman_adv_ptype.dev = hard_iface->net_dev;
    dev_add_pack(&hard_iface->batman_adv_ptype);

    atomic_set(&hard_iface->frag_seqno, 1);
    batadv_info(hard_iface->soft_iface, "Adding interface: %s\n",
            hard_iface->net_dev->name);

    if (atomic_read(&bat_priv->fragmentation) &&
        hard_iface->net_dev->mtu < ETH_DATA_LEN + BATADV_HEADER_LEN)
        batadv_info(hard_iface->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",
                hard_iface->net_dev->name, hard_iface->net_dev->mtu,
                ETH_DATA_LEN + BATADV_HEADER_LEN);

    if (!atomic_read(&bat_priv->fragmentation) &&
        hard_iface->net_dev->mtu < ETH_DATA_LEN + BATADV_HEADER_LEN)
        batadv_info(hard_iface->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",
                hard_iface->net_dev->name, hard_iface->net_dev->mtu,
                ETH_DATA_LEN + BATADV_HEADER_LEN);

    if (batadv_hardif_is_iface_up(hard_iface))
        batadv_hardif_activate_interface(hard_iface);
    else
        batadv_err(hard_iface->soft_iface,
               "Not using interface %s (retrying later): interface not active\n",
               hard_iface->net_dev->name);

    /* begin scheduling originator messages on that interface */
    batadv_schedule_bat_ogm(hard_iface);

out:
    return 0;

err_dev:
    dev_put(soft_iface);
err:
    batadv_hardif_free_ref(hard_iface);
    return ret;
}

void batadv_hardif_disable_interface(struct batadv_hard_iface *hard_iface)
{
    struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
    struct batadv_hard_iface *primary_if = NULL;

    if (hard_iface->if_status == BATADV_IF_ACTIVE)
        batadv_hardif_deactivate_interface(hard_iface);

    if (hard_iface->if_status != BATADV_IF_INACTIVE)
        goto out;

    batadv_info(hard_iface->soft_iface, "Removing interface: %s\n",
            hard_iface->net_dev->name);
    dev_remove_pack(&hard_iface->batman_adv_ptype);

    bat_priv->num_ifaces--;
    batadv_orig_hash_del_if(hard_iface, bat_priv->num_ifaces);

    primary_if = batadv_primary_if_get_selected(bat_priv);
    if (hard_iface == primary_if) {
        struct batadv_hard_iface *new_if;

        new_if = batadv_hardif_get_active(hard_iface->soft_iface);
        batadv_primary_if_select(bat_priv, new_if);

        if (new_if)
            batadv_hardif_free_ref(new_if);
    }

    bat_priv->bat_algo_ops->bat_iface_disable(hard_iface);
    hard_iface->if_status = BATADV_IF_NOT_IN_USE;

    /* delete all references to this hard_iface */
    batadv_purge_orig_ref(bat_priv);
    batadv_purge_outstanding_packets(bat_priv, hard_iface);
    dev_put(hard_iface->soft_iface);

    /* nobody uses this interface anymore */
    if (!bat_priv->num_ifaces)
        batadv_softif_destroy(hard_iface->soft_iface);

    hard_iface->soft_iface = NULL;
    batadv_hardif_free_ref(hard_iface);

out:
    if (primary_if)
        batadv_hardif_free_ref(primary_if);
}

static struct batadv_hard_iface *
batadv_hardif_add_interface(struct net_device *net_dev)
{
    struct batadv_hard_iface *hard_iface;
    int ret;

    ASSERT_RTNL();

    ret = batadv_is_valid_iface(net_dev);
    if (ret != 1)
        goto out;

    dev_hold(net_dev);

    hard_iface = kmalloc(sizeof(*hard_iface), GFP_ATOMIC);
    if (!hard_iface)
        goto release_dev;

    ret = batadv_sysfs_add_hardif(&hard_iface->hardif_obj, net_dev);
    if (ret)
        goto free_if;

    hard_iface->if_num = -1;
    hard_iface->net_dev = net_dev;
    hard_iface->soft_iface = NULL;
    hard_iface->if_status = BATADV_IF_NOT_IN_USE;
    INIT_LIST_HEAD(&hard_iface->list);
    /* extra reference for return */
    atomic_set(&hard_iface->refcount, 2);

    batadv_check_known_mac_addr(hard_iface->net_dev);
    list_add_tail_rcu(&hard_iface->list, &batadv_hardif_list);

    /* This can't be called via a bat_priv callback because
     * we have no bat_priv yet.
     */
    atomic_set(&hard_iface->seqno, 1);
    hard_iface->packet_buff = NULL;

    return hard_iface;

free_if:
    kfree(hard_iface);
release_dev:
    dev_put(net_dev);
out:
    return NULL;
}

static void batadv_hardif_remove_interface(struct batadv_hard_iface *hard_iface)
{
    ASSERT_RTNL();

    /* first deactivate interface */
    if (hard_iface->if_status != BATADV_IF_NOT_IN_USE)
        batadv_hardif_disable_interface(hard_iface);

    if (hard_iface->if_status != BATADV_IF_NOT_IN_USE)
        return;

    hard_iface->if_status = BATADV_IF_TO_BE_REMOVED;
    batadv_sysfs_del_hardif(&hard_iface->hardif_obj);
    batadv_hardif_free_ref(hard_iface);
}

void batadv_hardif_remove_interfaces(void)
{
    struct batadv_hard_iface *hard_iface, *hard_iface_tmp;

    rtnl_lock();
    list_for_each_entry_safe(hard_iface, hard_iface_tmp,
                 &batadv_hardif_list, list) {
        list_del_rcu(&hard_iface->list);
        batadv_hardif_remove_interface(hard_iface);
    }
    rtnl_unlock();
}

static int batadv_hard_if_event(struct notifier_block *this,
                unsigned long event, void *ptr)
{
    struct net_device *net_dev = ptr;
    struct batadv_hard_iface *hard_iface;
    struct batadv_hard_iface *primary_if = NULL;
    struct batadv_priv *bat_priv;

    hard_iface = batadv_hardif_get_by_netdev(net_dev);
    if (!hard_iface && event == NETDEV_REGISTER)
        hard_iface = batadv_hardif_add_interface(net_dev);

    if (!hard_iface)
        goto out;

    switch (event) {
    case NETDEV_UP:
        batadv_hardif_activate_interface(hard_iface);
        break;
    case NETDEV_GOING_DOWN:
    case NETDEV_DOWN:
        batadv_hardif_deactivate_interface(hard_iface);
        break;
    case NETDEV_UNREGISTER:
        list_del_rcu(&hard_iface->list);

        batadv_hardif_remove_interface(hard_iface);
        break;
    case NETDEV_CHANGEMTU:
        if (hard_iface->soft_iface)
            batadv_update_min_mtu(hard_iface->soft_iface);
        break;
    case NETDEV_CHANGEADDR:
        if (hard_iface->if_status == BATADV_IF_NOT_IN_USE)
            goto hardif_put;

        batadv_check_known_mac_addr(hard_iface->net_dev);

        bat_priv = netdev_priv(hard_iface->soft_iface);
        bat_priv->bat_algo_ops->bat_iface_update_mac(hard_iface);

        primary_if = batadv_primary_if_get_selected(bat_priv);
        if (!primary_if)
            goto hardif_put;

        if (hard_iface == primary_if)
            batadv_primary_if_update_addr(bat_priv, NULL);
        break;
    default:
        break;
    }

hardif_put:
    batadv_hardif_free_ref(hard_iface);
out:
    if (primary_if)
        batadv_hardif_free_ref(primary_if);
    return NOTIFY_DONE;
}

/* This function returns true if the interface represented by ifindex is a
 * 802.11 wireless device
 */
bool batadv_is_wifi_iface(int ifindex)
{
    struct net_device *net_device = NULL;
    bool ret = false;

    if (ifindex == BATADV_NULL_IFINDEX)
        goto out;

    net_device = dev_get_by_index(&init_net, ifindex);
    if (!net_device)
        goto out;

#ifdef CONFIG_WIRELESS_EXT
    /* pre-cfg80211 drivers have to implement WEXT, so it is possible to
     * check for wireless_handlers != NULL
     */
    if (net_device->wireless_handlers)
        ret = true;
    else
#endif
        /* cfg80211 drivers have to set ieee80211_ptr */
        if (net_device->ieee80211_ptr)
            ret = true;
out:
    if (net_device)
        dev_put(net_device);
    return ret;
}

struct notifier_block batadv_hard_if_notifier = {
    .notifier_call = batadv_hard_if_event,
};