net/batman-adv/send.c

   1 /* Copyright (C) 2007-2013 B.A.T.M.A.N. contributors:
   2  *
   3  * Marek Lindner, Simon Wunderlich
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of version 2 of the GNU General Public
   7  * License as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  17  * 02110-1301, USA
  18  */
  19
  20 #include "main.h"
  21 #include "distributed-arp-table.h"
  22 #include "send.h"
  23 #include "routing.h"
  24 #include "translation-table.h"
  25 #include "soft-interface.h"
  26 #include "hard-interface.h"
  27 #include "vis.h"
  28 #include "gateway_common.h"
  29 #include "originator.h"
  30 #include "network-coding.h"
  31
  32 #include <linux/if_ether.h>
  33
  34 static void batadv_send_outstanding_bcast_packet(struct work_struct *work);
  35
  36 /* send out an already prepared packet to the given address via the
  37  * specified batman interface
  38  */
  39 int batadv_send_skb_packet(struct sk_buff *skb,
  40                            struct batadv_hard_iface *hard_iface,
  41                            const uint8_t *dst_addr)
  42 {
  43         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
  44         struct ethhdr *ethhdr;
  45
  46         if (hard_iface->if_status != BATADV_IF_ACTIVE)
  47                 goto send_skb_err;
  48
  49         if (unlikely(!hard_iface->net_dev))
  50                 goto send_skb_err;
  51
  52         if (!(hard_iface->net_dev->flags & IFF_UP)) {
  53                 pr_warn("Interface %s is not up - can't send packet via that interface!\n",
  54                         hard_iface->net_dev->name);
  55                 goto send_skb_err;
  56         }
  57
  58         /* push to the ethernet header. */
  59         if (batadv_skb_head_push(skb, ETH_HLEN) < 0)
  60                 goto send_skb_err;
  61
  62         skb_reset_mac_header(skb);
  63
  64         ethhdr = (struct ethhdr *)skb_mac_header(skb);
  65         memcpy(ethhdr->h_source, hard_iface->net_dev->dev_addr, ETH_ALEN);
  66         memcpy(ethhdr->h_dest, dst_addr, ETH_ALEN);
  67         ethhdr->h_proto = __constant_htons(ETH_P_BATMAN);
  68
  69         skb_set_network_header(skb, ETH_HLEN);
  70         skb->priority = TC_PRIO_CONTROL;
  71         skb->protocol = __constant_htons(ETH_P_BATMAN);
  72
  73         skb->dev = hard_iface->net_dev;
  74
  75         /* Save a clone of the skb to use when decoding coded packets */
  76         batadv_nc_skb_store_for_decoding(bat_priv, skb);
  77
  78         /* dev_queue_xmit() returns a negative result on error.  However on
  79          * congestion and traffic shaping, it drops and returns NET_XMIT_DROP
  80          * (which is > 0). This will not be treated as an error.
  81          */
  82         return dev_queue_xmit(skb);
  83 send_skb_err:
  84         kfree_skb(skb);
  85         return NET_XMIT_DROP;
  86 }
  87
  88 /**
  89  * batadv_send_skb_to_orig - Lookup next-hop and transmit skb.
  90  * @skb: Packet to be transmitted.
  91  * @orig_node: Final destination of the packet.
  92  * @recv_if: Interface used when receiving the packet (can be NULL).
  93  *
  94  * Looks up the best next-hop towards the passed originator and passes the
  95  * skb on for preparation of MAC header. If the packet originated from this
  96  * host, NULL can be passed as recv_if and no interface alternating is
  97  * attempted.
  98  *
  99  * Returns TRUE on success; FALSE otherwise.
 100  */
 101 bool batadv_send_skb_to_orig(struct sk_buff *skb,
 102                              struct batadv_orig_node *orig_node,
 103                              struct batadv_hard_iface *recv_if)
 104 {
 105         struct batadv_priv *bat_priv = orig_node->bat_priv;
 106         struct batadv_neigh_node *neigh_node;
 107
 108         /* batadv_find_router() increases neigh_nodes refcount if found. */
 109         neigh_node = batadv_find_router(bat_priv, orig_node, recv_if);
 110         if (!neigh_node)
 111                 return false;
 112
 113         /* route it */
 114         batadv_send_skb_packet(skb, neigh_node->if_incoming, neigh_node->addr);
 115
 116         batadv_neigh_node_free_ref(neigh_node);
 117
 118         return true;
 119 }
 120
 121 void batadv_schedule_bat_ogm(struct batadv_hard_iface *hard_iface)
 122 {
 123         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 124
 125         if ((hard_iface->if_status == BATADV_IF_NOT_IN_USE) ||
 126             (hard_iface->if_status == BATADV_IF_TO_BE_REMOVED))
 127                 return;
 128
 129         /* the interface gets activated here to avoid race conditions between
 130          * the moment of activating the interface in
 131          * hardif_activate_interface() where the originator mac is set and
 132          * outdated packets (especially uninitialized mac addresses) in the
 133          * packet queue
 134          */
 135         if (hard_iface->if_status == BATADV_IF_TO_BE_ACTIVATED)
 136                 hard_iface->if_status = BATADV_IF_ACTIVE;
 137
 138         bat_priv->bat_algo_ops->bat_ogm_schedule(hard_iface);
 139 }
 140
 141 static void batadv_forw_packet_free(struct batadv_forw_packet *forw_packet)
 142 {
 143         if (forw_packet->skb)
 144                 kfree_skb(forw_packet->skb);
 145         if (forw_packet->if_incoming)
 146                 batadv_hardif_free_ref(forw_packet->if_incoming);
 147         kfree(forw_packet);
 148 }
 149
 150 static void
 151 _batadv_add_bcast_packet_to_list(struct batadv_priv *bat_priv,
 152                                  struct batadv_forw_packet *forw_packet,
 153                                  unsigned long send_time)
 154 {
 155         INIT_HLIST_NODE(&forw_packet->list);
 156
 157         /* add new packet to packet list */
 158         spin_lock_bh(&bat_priv->forw_bcast_list_lock);
 159         hlist_add_head(&forw_packet->list, &bat_priv->forw_bcast_list);
 160         spin_unlock_bh(&bat_priv->forw_bcast_list_lock);
 161
 162         /* start timer for this packet */
 163         queue_delayed_work(batadv_event_workqueue, &forw_packet->delayed_work,
 164                            send_time);
 165 }
 166
 167 /* add a broadcast packet to the queue and setup timers. broadcast packets
 168  * are sent multiple times to increase probability for being received.
 169  *
 170  * This function returns NETDEV_TX_OK on success and NETDEV_TX_BUSY on
 171  * errors.
 172  *
 173  * The skb is not consumed, so the caller should make sure that the
 174  * skb is freed.
 175  */
 176 int batadv_add_bcast_packet_to_list(struct batadv_priv *bat_priv,
 177                                     const struct sk_buff *skb,
 178                                     unsigned long delay)
 179 {
 180         struct batadv_hard_iface *primary_if = NULL;
 181         struct batadv_forw_packet *forw_packet;
 182         struct batadv_bcast_packet *bcast_packet;
 183         struct sk_buff *newskb;
 184
 185         if (!batadv_atomic_dec_not_zero(&bat_priv->bcast_queue_left)) {
 186                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 187                            "bcast packet queue full\n");
 188                 goto out;
 189         }
 190
 191         primary_if = batadv_primary_if_get_selected(bat_priv);
 192         if (!primary_if)
 193                 goto out_and_inc;
 194
 195         forw_packet = kmalloc(sizeof(*forw_packet), GFP_ATOMIC);
 196
 197         if (!forw_packet)
 198                 goto out_and_inc;
 199
 200         newskb = skb_copy(skb, GFP_ATOMIC);
 201         if (!newskb)
 202                 goto packet_free;
 203
 204         /* as we have a copy now, it is safe to decrease the TTL */
 205         bcast_packet = (struct batadv_bcast_packet *)newskb->data;
 206         bcast_packet->header.ttl--;
 207
 208         skb_reset_mac_header(newskb);
 209
 210         forw_packet->skb = newskb;
 211         forw_packet->if_incoming = primary_if;
 212
 213         /* how often did we send the bcast packet ? */
 214         forw_packet->num_packets = 0;
 215
 216         INIT_DELAYED_WORK(&forw_packet->delayed_work,
 217                           batadv_send_outstanding_bcast_packet);
 218
 219         _batadv_add_bcast_packet_to_list(bat_priv, forw_packet, delay);
 220         return NETDEV_TX_OK;
 221
 222 packet_free:
 223         kfree(forw_packet);
 224 out_and_inc:
 225         atomic_inc(&bat_priv->bcast_queue_left);
 226 out:
 227         if (primary_if)
 228                 batadv_hardif_free_ref(primary_if);
 229         return NETDEV_TX_BUSY;
 230 }
 231
 232 static void batadv_send_outstanding_bcast_packet(struct work_struct *work)
 233 {
 234         struct batadv_hard_iface *hard_iface;
 235         struct delayed_work *delayed_work;
 236         struct batadv_forw_packet *forw_packet;
 237         struct sk_buff *skb1;
 238         struct net_device *soft_iface;
 239         struct batadv_priv *bat_priv;
 240
 241         delayed_work = container_of(work, struct delayed_work, work);
 242         forw_packet = container_of(delayed_work, struct batadv_forw_packet,
 243                                    delayed_work);
 244         soft_iface = forw_packet->if_incoming->soft_iface;
 245         bat_priv = netdev_priv(soft_iface);
 246
 247         spin_lock_bh(&bat_priv->forw_bcast_list_lock);
 248         hlist_del(&forw_packet->list);
 249         spin_unlock_bh(&bat_priv->forw_bcast_list_lock);
 250
 251         if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)
 252                 goto out;
 253
 254         if (batadv_dat_drop_broadcast_packet(bat_priv, forw_packet))
 255                 goto out;
 256
 257         /* rebroadcast packet */
 258         rcu_read_lock();
 259         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 260                 if (hard_iface->soft_iface != soft_iface)
 261                         continue;
 262
 263                 /* send a copy of the saved skb */
 264                 skb1 = skb_clone(forw_packet->skb, GFP_ATOMIC);
 265                 if (skb1)
 266                         batadv_send_skb_packet(skb1, hard_iface,
 267                                                batadv_broadcast_addr);
 268         }
 269         rcu_read_unlock();
 270
 271         forw_packet->num_packets++;
 272
 273         /* if we still have some more bcasts to send */
 274         if (forw_packet->num_packets < 3) {
 275                 _batadv_add_bcast_packet_to_list(bat_priv, forw_packet,
 276                                                  msecs_to_jiffies(5));
 277                 return;
 278         }
 279
 280 out:
 281         batadv_forw_packet_free(forw_packet);
 282         atomic_inc(&bat_priv->bcast_queue_left);
 283 }
 284
 285 void batadv_send_outstanding_bat_ogm_packet(struct work_struct *work)
 286 {
 287         struct delayed_work *delayed_work;
 288         struct batadv_forw_packet *forw_packet;
 289         struct batadv_priv *bat_priv;
 290
 291         delayed_work = container_of(work, struct delayed_work, work);
 292         forw_packet = container_of(delayed_work, struct batadv_forw_packet,
 293                                    delayed_work);
 294         bat_priv = netdev_priv(forw_packet->if_incoming->soft_iface);
 295         spin_lock_bh(&bat_priv->forw_bat_list_lock);
 296         hlist_del(&forw_packet->list);
 297         spin_unlock_bh(&bat_priv->forw_bat_list_lock);
 298
 299         if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)
 300                 goto out;
 301
 302         bat_priv->bat_algo_ops->bat_ogm_emit(forw_packet);
 303
 304         /* we have to have at least one packet in the queue
 305          * to determine the queues wake up time unless we are
 306          * shutting down
 307          */
 308         if (forw_packet->own)
 309                 batadv_schedule_bat_ogm(forw_packet->if_incoming);
 310
 311 out:
 312         /* don't count own packet */
 313         if (!forw_packet->own)
 314                 atomic_inc(&bat_priv->batman_queue_left);
 315
 316         batadv_forw_packet_free(forw_packet);
 317 }
 318
 319 void
 320 batadv_purge_outstanding_packets(struct batadv_priv *bat_priv,
 321                                  const struct batadv_hard_iface *hard_iface)
 322 {
 323         struct batadv_forw_packet *forw_packet;
 324         struct hlist_node *safe_tmp_node;
 325         bool pending;
 326
 327         if (hard_iface)
 328                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 329                            "purge_outstanding_packets(): %s\n",
 330                            hard_iface->net_dev->name);
 331         else
 332                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 333                            "purge_outstanding_packets()\n");
 334
 335         /* free bcast list */
 336         spin_lock_bh(&bat_priv->forw_bcast_list_lock);
 337         hlist_for_each_entry_safe(forw_packet, safe_tmp_node,
 338                                   &bat_priv->forw_bcast_list, list) {
 339                 /* if purge_outstanding_packets() was called with an argument
 340                  * we delete only packets belonging to the given interface
 341                  */
 342                 if ((hard_iface) &&
 343                     (forw_packet->if_incoming != hard_iface))
 344                         continue;
 345
 346                 spin_unlock_bh(&bat_priv->forw_bcast_list_lock);
 347
 348                 /* batadv_send_outstanding_bcast_packet() will lock the list to
 349                  * delete the item from the list
 350                  */
 351                 pending = cancel_delayed_work_sync(&forw_packet->delayed_work);
 352                 spin_lock_bh(&bat_priv->forw_bcast_list_lock);
 353
 354                 if (pending) {
 355                         hlist_del(&forw_packet->list);
 356                         batadv_forw_packet_free(forw_packet);
 357                 }
 358         }
 359         spin_unlock_bh(&bat_priv->forw_bcast_list_lock);
 360
 361         /* free batman packet list */
 362         spin_lock_bh(&bat_priv->forw_bat_list_lock);
 363         hlist_for_each_entry_safe(forw_packet, safe_tmp_node,
 364                                   &bat_priv->forw_bat_list, list) {
 365                 /* if purge_outstanding_packets() was called with an argument
 366                  * we delete only packets belonging to the given interface
 367                  */
 368                 if ((hard_iface) &&
 369                     (forw_packet->if_incoming != hard_iface))
 370                         continue;
 371
 372                 spin_unlock_bh(&bat_priv->forw_bat_list_lock);
 373
 374                 /* send_outstanding_bat_packet() will lock the list to
 375                  * delete the item from the list
 376                  */
 377                 pending = cancel_delayed_work_sync(&forw_packet->delayed_work);
 378                 spin_lock_bh(&bat_priv->forw_bat_list_lock);
 379
 380                 if (pending) {
 381                         hlist_del(&forw_packet->list);
 382                         batadv_forw_packet_free(forw_packet);
 383                 }
 384         }
 385         spin_unlock_bh(&bat_priv->forw_bat_list_lock);
 386 }