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 = eth_hdr(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 NET_XMIT_SUCCESS on success, NET_XMIT_DROP on failure, or
 100  * NET_XMIT_POLICED if the skb is buffered for later transmit.
 101  */
 102 int batadv_send_skb_to_orig(struct sk_buff *skb,
 103                             struct batadv_orig_node *orig_node,
 104                             struct batadv_hard_iface *recv_if)
 105 {
 106         struct batadv_priv *bat_priv = orig_node->bat_priv;
 107         struct batadv_neigh_node *neigh_node;
 108         int ret = NET_XMIT_DROP;
 109
 110         /* batadv_find_router() increases neigh_nodes refcount if found. */
 111         neigh_node = batadv_find_router(bat_priv, orig_node, recv_if);
 112         if (!neigh_node)
 113                 return ret;
 114
 115         /* try to network code the packet, if it is received on an interface
 116          * (i.e. being forwarded). If the packet originates from this node or if
 117          * network coding fails, then send the packet as usual.
 118          */
 119         if (recv_if && batadv_nc_skb_forward(skb, neigh_node)) {
 120                 ret = NET_XMIT_POLICED;
 121         } else {
 122                 batadv_send_skb_packet(skb, neigh_node->if_incoming,
 123                                        neigh_node->addr);
 124                 ret = NET_XMIT_SUCCESS;
 125         }
 126
 127         batadv_neigh_node_free_ref(neigh_node);
 128
 129         return ret;
 130 }
 131
 132 void batadv_schedule_bat_ogm(struct batadv_hard_iface *hard_iface)
 133 {
 134         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 135
 136         if ((hard_iface->if_status == BATADV_IF_NOT_IN_USE) ||
 137             (hard_iface->if_status == BATADV_IF_TO_BE_REMOVED))
 138                 return;
 139
 140         /* the interface gets activated here to avoid race conditions between
 141          * the moment of activating the interface in
 142          * hardif_activate_interface() where the originator mac is set and
 143          * outdated packets (especially uninitialized mac addresses) in the
 144          * packet queue
 145          */
 146         if (hard_iface->if_status == BATADV_IF_TO_BE_ACTIVATED)
 147                 hard_iface->if_status = BATADV_IF_ACTIVE;
 148
 149         bat_priv->bat_algo_ops->bat_ogm_schedule(hard_iface);
 150 }
 151
 152 static void batadv_forw_packet_free(struct batadv_forw_packet *forw_packet)
 153 {
 154         if (forw_packet->skb)
 155                 kfree_skb(forw_packet->skb);
 156         if (forw_packet->if_incoming)
 157                 batadv_hardif_free_ref(forw_packet->if_incoming);
 158         kfree(forw_packet);
 159 }
 160
 161 static void
 162 _batadv_add_bcast_packet_to_list(struct batadv_priv *bat_priv,
 163                                  struct batadv_forw_packet *forw_packet,
 164                                  unsigned long send_time)
 165 {
 166         /* add new packet to packet list */
 167         spin_lock_bh(&bat_priv->forw_bcast_list_lock);
 168         hlist_add_head(&forw_packet->list, &bat_priv->forw_bcast_list);
 169         spin_unlock_bh(&bat_priv->forw_bcast_list_lock);
 170
 171         /* start timer for this packet */
 172         queue_delayed_work(batadv_event_workqueue, &forw_packet->delayed_work,
 173                            send_time);
 174 }
 175
 176 /* add a broadcast packet to the queue and setup timers. broadcast packets
 177  * are sent multiple times to increase probability for being received.
 178  *
 179  * This function returns NETDEV_TX_OK on success and NETDEV_TX_BUSY on
 180  * errors.
 181  *
 182  * The skb is not consumed, so the caller should make sure that the
 183  * skb is freed.
 184  */
 185 int batadv_add_bcast_packet_to_list(struct batadv_priv *bat_priv,
 186                                     const struct sk_buff *skb,
 187                                     unsigned long delay)
 188 {
 189         struct batadv_hard_iface *primary_if = NULL;
 190         struct batadv_forw_packet *forw_packet;
 191         struct batadv_bcast_packet *bcast_packet;
 192         struct sk_buff *newskb;
 193
 194         if (!batadv_atomic_dec_not_zero(&bat_priv->bcast_queue_left)) {
 195                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 196                            "bcast packet queue full\n");
 197                 goto out;
 198         }
 199
 200         primary_if = batadv_primary_if_get_selected(bat_priv);
 201         if (!primary_if)
 202                 goto out_and_inc;
 203
 204         forw_packet = kmalloc(sizeof(*forw_packet), GFP_ATOMIC);
 205
 206         if (!forw_packet)
 207                 goto out_and_inc;
 208
 209         newskb = skb_copy(skb, GFP_ATOMIC);
 210         if (!newskb)
 211                 goto packet_free;
 212
 213         /* as we have a copy now, it is safe to decrease the TTL */
 214         bcast_packet = (struct batadv_bcast_packet *)newskb->data;
 215         bcast_packet->header.ttl--;
 216
 217         skb_reset_mac_header(newskb);
 218
 219         forw_packet->skb = newskb;
 220         forw_packet->if_incoming = primary_if;
 221
 222         /* how often did we send the bcast packet ? */
 223         forw_packet->num_packets = 0;
 224
 225         INIT_DELAYED_WORK(&forw_packet->delayed_work,
 226                           batadv_send_outstanding_bcast_packet);
 227
 228         _batadv_add_bcast_packet_to_list(bat_priv, forw_packet, delay);
 229         return NETDEV_TX_OK;
 230
 231 packet_free:
 232         kfree(forw_packet);
 233 out_and_inc:
 234         atomic_inc(&bat_priv->bcast_queue_left);
 235 out:
 236         if (primary_if)
 237                 batadv_hardif_free_ref(primary_if);
 238         return NETDEV_TX_BUSY;
 239 }
 240
 241 static void batadv_send_outstanding_bcast_packet(struct work_struct *work)
 242 {
 243         struct batadv_hard_iface *hard_iface;
 244         struct delayed_work *delayed_work;
 245         struct batadv_forw_packet *forw_packet;
 246         struct sk_buff *skb1;
 247         struct net_device *soft_iface;
 248         struct batadv_priv *bat_priv;
 249
 250         delayed_work = container_of(work, struct delayed_work, work);
 251         forw_packet = container_of(delayed_work, struct batadv_forw_packet,
 252                                    delayed_work);
 253         soft_iface = forw_packet->if_incoming->soft_iface;
 254         bat_priv = netdev_priv(soft_iface);
 255
 256         spin_lock_bh(&bat_priv->forw_bcast_list_lock);
 257         hlist_del(&forw_packet->list);
 258         spin_unlock_bh(&bat_priv->forw_bcast_list_lock);
 259
 260         if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)
 261                 goto out;
 262
 263         if (batadv_dat_drop_broadcast_packet(bat_priv, forw_packet))
 264                 goto out;
 265
 266         /* rebroadcast packet */
 267         rcu_read_lock();
 268         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 269                 if (hard_iface->soft_iface != soft_iface)
 270                         continue;
 271
 272                 if (forw_packet->num_packets >= hard_iface->num_bcasts)
 273                         continue;
 274
 275                 /* send a copy of the saved skb */
 276                 skb1 = skb_clone(forw_packet->skb, GFP_ATOMIC);
 277                 if (skb1)
 278                         batadv_send_skb_packet(skb1, hard_iface,
 279                                                batadv_broadcast_addr);
 280         }
 281         rcu_read_unlock();
 282
 283         forw_packet->num_packets++;
 284
 285         /* if we still have some more bcasts to send */
 286         if (forw_packet->num_packets < BATADV_NUM_BCASTS_MAX) {
 287                 _batadv_add_bcast_packet_to_list(bat_priv, forw_packet,
 288                                                  msecs_to_jiffies(5));
 289                 return;
 290         }
 291
 292 out:
 293         batadv_forw_packet_free(forw_packet);
 294         atomic_inc(&bat_priv->bcast_queue_left);
 295 }
 296
 297 void batadv_send_outstanding_bat_ogm_packet(struct work_struct *work)
 298 {
 299         struct delayed_work *delayed_work;
 300         struct batadv_forw_packet *forw_packet;
 301         struct batadv_priv *bat_priv;
 302
 303         delayed_work = container_of(work, struct delayed_work, work);
 304         forw_packet = container_of(delayed_work, struct batadv_forw_packet,
 305                                    delayed_work);
 306         bat_priv = netdev_priv(forw_packet->if_incoming->soft_iface);
 307         spin_lock_bh(&bat_priv->forw_bat_list_lock);
 308         hlist_del(&forw_packet->list);
 309         spin_unlock_bh(&bat_priv->forw_bat_list_lock);
 310
 311         if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)
 312                 goto out;
 313
 314         bat_priv->bat_algo_ops->bat_ogm_emit(forw_packet);
 315
 316         /* we have to have at least one packet in the queue
 317          * to determine the queues wake up time unless we are
 318          * shutting down
 319          */
 320         if (forw_packet->own)
 321                 batadv_schedule_bat_ogm(forw_packet->if_incoming);
 322
 323 out:
 324         /* don't count own packet */
 325         if (!forw_packet->own)
 326                 atomic_inc(&bat_priv->batman_queue_left);
 327
 328         batadv_forw_packet_free(forw_packet);
 329 }
 330
 331 void
 332 batadv_purge_outstanding_packets(struct batadv_priv *bat_priv,
 333                                  const struct batadv_hard_iface *hard_iface)
 334 {
 335         struct batadv_forw_packet *forw_packet;
 336         struct hlist_node *safe_tmp_node;
 337         bool pending;
 338
 339         if (hard_iface)
 340                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 341                            "purge_outstanding_packets(): %s\n",
 342                            hard_iface->net_dev->name);
 343         else
 344                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 345                            "purge_outstanding_packets()\n");
 346
 347         /* free bcast list */
 348         spin_lock_bh(&bat_priv->forw_bcast_list_lock);
 349         hlist_for_each_entry_safe(forw_packet, safe_tmp_node,
 350                                   &bat_priv->forw_bcast_list, list) {
 351                 /* if purge_outstanding_packets() was called with an argument
 352                  * we delete only packets belonging to the given interface
 353                  */
 354                 if ((hard_iface) &&
 355                     (forw_packet->if_incoming != hard_iface))
 356                         continue;
 357
 358                 spin_unlock_bh(&bat_priv->forw_bcast_list_lock);
 359
 360                 /* batadv_send_outstanding_bcast_packet() will lock the list to
 361                  * delete the item from the list
 362                  */
 363                 pending = cancel_delayed_work_sync(&forw_packet->delayed_work);
 364                 spin_lock_bh(&bat_priv->forw_bcast_list_lock);
 365
 366                 if (pending) {
 367                         hlist_del(&forw_packet->list);
 368                         batadv_forw_packet_free(forw_packet);
 369                 }
 370         }
 371         spin_unlock_bh(&bat_priv->forw_bcast_list_lock);
 372
 373         /* free batman packet list */
 374         spin_lock_bh(&bat_priv->forw_bat_list_lock);
 375         hlist_for_each_entry_safe(forw_packet, safe_tmp_node,
 376                                   &bat_priv->forw_bat_list, list) {
 377                 /* if purge_outstanding_packets() was called with an argument
 378                  * we delete only packets belonging to the given interface
 379                  */
 380                 if ((hard_iface) &&
 381                     (forw_packet->if_incoming != hard_iface))
 382                         continue;
 383
 384                 spin_unlock_bh(&bat_priv->forw_bat_list_lock);
 385
 386                 /* send_outstanding_bat_packet() will lock the list to
 387                  * delete the item from the list
 388                  */
 389                 pending = cancel_delayed_work_sync(&forw_packet->delayed_work);
 390                 spin_lock_bh(&bat_priv->forw_bat_list_lock);
 391
 392                 if (pending) {
 393                         hlist_del(&forw_packet->list);
 394                         batadv_forw_packet_free(forw_packet);
 395                 }
 396         }
 397         spin_unlock_bh(&bat_priv->forw_bat_list_lock);
 398 }