send.c

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/* 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 "send.h"
#include "routing.h"
#include "translation-table.h"
#include "soft-interface.h"
#include "hard-interface.h"
#include "vis.h"
#include "gateway_common.h"
#include "originator.h"

static void batadv_send_outstanding_bcast_packet(struct work_struct *work);

/* send out an already prepared packet to the given address via the
 * specified batman interface
 */
int batadv_send_skb_packet(struct sk_buff *skb,
               struct batadv_hard_iface *hard_iface,
               const uint8_t *dst_addr)
{
    struct ethhdr *ethhdr;

    if (hard_iface->if_status != BATADV_IF_ACTIVE)
        goto send_skb_err;

    if (unlikely(!hard_iface->net_dev))
        goto send_skb_err;

    if (!(hard_iface->net_dev->flags & IFF_UP)) {
        pr_warn("Interface %s is not up - can't send packet via that interface!\n",
            hard_iface->net_dev->name);
        goto send_skb_err;
    }

    /* push to the ethernet header. */
    if (batadv_skb_head_push(skb, ETH_HLEN) < 0)
        goto send_skb_err;

    skb_reset_mac_header(skb);

    ethhdr = (struct ethhdr *)skb_mac_header(skb);
    memcpy(ethhdr->h_source, hard_iface->net_dev->dev_addr, ETH_ALEN);
    memcpy(ethhdr->h_dest, dst_addr, ETH_ALEN);
    ethhdr->h_proto = __constant_htons(BATADV_ETH_P_BATMAN);

    skb_set_network_header(skb, ETH_HLEN);
    skb->priority = TC_PRIO_CONTROL;
    skb->protocol = __constant_htons(BATADV_ETH_P_BATMAN);

    skb->dev = hard_iface->net_dev;

    /* dev_queue_xmit() returns a negative result on error.  However on
     * congestion and traffic shaping, it drops and returns NET_XMIT_DROP
     * (which is > 0). This will not be treated as an error.
     */
    return dev_queue_xmit(skb);
send_skb_err:
    kfree_skb(skb);
    return NET_XMIT_DROP;
}

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

    if ((hard_iface->if_status == BATADV_IF_NOT_IN_USE) ||
        (hard_iface->if_status == BATADV_IF_TO_BE_REMOVED))
        return;

    /* the interface gets activated here to avoid race conditions between
     * the moment of activating the interface in
     * hardif_activate_interface() where the originator mac is set and
     * outdated packets (especially uninitialized mac addresses) in the
     * packet queue
     */
    if (hard_iface->if_status == BATADV_IF_TO_BE_ACTIVATED)
        hard_iface->if_status = BATADV_IF_ACTIVE;

    bat_priv->bat_algo_ops->bat_ogm_schedule(hard_iface);
}

static void batadv_forw_packet_free(struct batadv_forw_packet *forw_packet)
{
    if (forw_packet->skb)
        kfree_skb(forw_packet->skb);
    if (forw_packet->if_incoming)
        batadv_hardif_free_ref(forw_packet->if_incoming);
    kfree(forw_packet);
}

static void
_batadv_add_bcast_packet_to_list(struct batadv_priv *bat_priv,
                 struct batadv_forw_packet *forw_packet,
                 unsigned long send_time)
{
    INIT_HLIST_NODE(&forw_packet->list);

    /* add new packet to packet list */
    spin_lock_bh(&bat_priv->forw_bcast_list_lock);
    hlist_add_head(&forw_packet->list, &bat_priv->forw_bcast_list);
    spin_unlock_bh(&bat_priv->forw_bcast_list_lock);

    /* start timer for this packet */
    INIT_DELAYED_WORK(&forw_packet->delayed_work,
              batadv_send_outstanding_bcast_packet);
    queue_delayed_work(batadv_event_workqueue, &forw_packet->delayed_work,
               send_time);
}

/* add a broadcast packet to the queue and setup timers. broadcast packets
 * are sent multiple times to increase probability for being received.
 *
 * This function returns NETDEV_TX_OK on success and NETDEV_TX_BUSY on
 * errors.
 *
 * The skb is not consumed, so the caller should make sure that the
 * skb is freed.
 */
int batadv_add_bcast_packet_to_list(struct batadv_priv *bat_priv,
                    const struct sk_buff *skb,
                    unsigned long delay)
{
    struct batadv_hard_iface *primary_if = NULL;
    struct batadv_forw_packet *forw_packet;
    struct batadv_bcast_packet *bcast_packet;
    struct sk_buff *newskb;

    if (!batadv_atomic_dec_not_zero(&bat_priv->bcast_queue_left)) {
        batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
               "bcast packet queue full\n");
        goto out;
    }

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

    forw_packet = kmalloc(sizeof(*forw_packet), GFP_ATOMIC);

    if (!forw_packet)
        goto out_and_inc;

    newskb = skb_copy(skb, GFP_ATOMIC);
    if (!newskb)
        goto packet_free;

    /* as we have a copy now, it is safe to decrease the TTL */
    bcast_packet = (struct batadv_bcast_packet *)newskb->data;
    bcast_packet->header.ttl--;

    skb_reset_mac_header(newskb);

    forw_packet->skb = newskb;
    forw_packet->if_incoming = primary_if;

    /* how often did we send the bcast packet ? */
    forw_packet->num_packets = 0;

    _batadv_add_bcast_packet_to_list(bat_priv, forw_packet, delay);
    return NETDEV_TX_OK;

packet_free:
    kfree(forw_packet);
out_and_inc:
    atomic_inc(&bat_priv->bcast_queue_left);
out:
    if (primary_if)
        batadv_hardif_free_ref(primary_if);
    return NETDEV_TX_BUSY;
}

static void batadv_send_outstanding_bcast_packet(struct work_struct *work)
{
    struct batadv_hard_iface *hard_iface;
    struct delayed_work *delayed_work;
    struct batadv_forw_packet *forw_packet;
    struct sk_buff *skb1;
    struct net_device *soft_iface;
    struct batadv_priv *bat_priv;

    delayed_work = container_of(work, struct delayed_work, work);
    forw_packet = container_of(delayed_work, struct batadv_forw_packet,
                   delayed_work);
    soft_iface = forw_packet->if_incoming->soft_iface;
    bat_priv = netdev_priv(soft_iface);

    spin_lock_bh(&bat_priv->forw_bcast_list_lock);
    hlist_del(&forw_packet->list);
    spin_unlock_bh(&bat_priv->forw_bcast_list_lock);

    if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)
        goto out;

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

        /* send a copy of the saved skb */
        skb1 = skb_clone(forw_packet->skb, GFP_ATOMIC);
        if (skb1)
            batadv_send_skb_packet(skb1, hard_iface,
                           batadv_broadcast_addr);
    }
    rcu_read_unlock();

    forw_packet->num_packets++;

    /* if we still have some more bcasts to send */
    if (forw_packet->num_packets < 3) {
        _batadv_add_bcast_packet_to_list(bat_priv, forw_packet,
                         msecs_to_jiffies(5));
        return;
    }

out:
    batadv_forw_packet_free(forw_packet);
    atomic_inc(&bat_priv->bcast_queue_left);
}

void batadv_send_outstanding_bat_ogm_packet(struct work_struct *work)
{
    struct delayed_work *delayed_work;
    struct batadv_forw_packet *forw_packet;
    struct batadv_priv *bat_priv;

    delayed_work = container_of(work, struct delayed_work, work);
    forw_packet = container_of(delayed_work, struct batadv_forw_packet,
                   delayed_work);
    bat_priv = netdev_priv(forw_packet->if_incoming->soft_iface);
    spin_lock_bh(&bat_priv->forw_bat_list_lock);
    hlist_del(&forw_packet->list);
    spin_unlock_bh(&bat_priv->forw_bat_list_lock);

    if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)
        goto out;

    bat_priv->bat_algo_ops->bat_ogm_emit(forw_packet);

    /* we have to have at least one packet in the queue
     * to determine the queues wake up time unless we are
     * shutting down
     */
    if (forw_packet->own)
        batadv_schedule_bat_ogm(forw_packet->if_incoming);

out:
    /* don't count own packet */
    if (!forw_packet->own)
        atomic_inc(&bat_priv->batman_queue_left);

    batadv_forw_packet_free(forw_packet);
}

void
batadv_purge_outstanding_packets(struct batadv_priv *bat_priv,
                 const struct batadv_hard_iface *hard_iface)
{
    struct batadv_forw_packet *forw_packet;
    struct hlist_node *tmp_node, *safe_tmp_node;
    bool pending;

    if (hard_iface)
        batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
               "purge_outstanding_packets(): %s\n",
               hard_iface->net_dev->name);
    else
        batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
               "purge_outstanding_packets()\n");

    /* free bcast list */
    spin_lock_bh(&bat_priv->forw_bcast_list_lock);
    hlist_for_each_entry_safe(forw_packet, tmp_node, safe_tmp_node,
                  &bat_priv->forw_bcast_list, list) {

        /* if purge_outstanding_packets() was called with an argument
         * we delete only packets belonging to the given interface
         */
        if ((hard_iface) &&
            (forw_packet->if_incoming != hard_iface))
            continue;

        spin_unlock_bh(&bat_priv->forw_bcast_list_lock);

        /* batadv_send_outstanding_bcast_packet() will lock the list to
         * delete the item from the list
         */
        pending = cancel_delayed_work_sync(&forw_packet->delayed_work);
        spin_lock_bh(&bat_priv->forw_bcast_list_lock);

        if (pending) {
            hlist_del(&forw_packet->list);
            batadv_forw_packet_free(forw_packet);
        }
    }
    spin_unlock_bh(&bat_priv->forw_bcast_list_lock);

    /* free batman packet list */
    spin_lock_bh(&bat_priv->forw_bat_list_lock);
    hlist_for_each_entry_safe(forw_packet, tmp_node, safe_tmp_node,
                  &bat_priv->forw_bat_list, list) {

        /* if purge_outstanding_packets() was called with an argument
         * we delete only packets belonging to the given interface
         */
        if ((hard_iface) &&
            (forw_packet->if_incoming != hard_iface))
            continue;

        spin_unlock_bh(&bat_priv->forw_bat_list_lock);

        /* send_outstanding_bat_packet() will lock the list to
         * delete the item from the list
         */
        pending = cancel_delayed_work_sync(&forw_packet->delayed_work);
        spin_lock_bh(&bat_priv->forw_bat_list_lock);

        if (pending) {
            hlist_del(&forw_packet->list);
            batadv_forw_packet_free(forw_packet);
        }
    }
    spin_unlock_bh(&bat_priv->forw_bat_list_lock);
}