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->protocol = __constant_htons(ETH_P_BATMAN);
  71
  72         skb->dev = hard_iface->net_dev;
  73
  74         /* Save a clone of the skb to use when decoding coded packets */
  75         batadv_nc_skb_store_for_decoding(bat_priv, skb);
  76
  77         /* dev_queue_xmit() returns a negative result on error.  However on
  78          * congestion and traffic shaping, it drops and returns NET_XMIT_DROP
  79          * (which is > 0). This will not be treated as an error.
  80          */
  81         return dev_queue_xmit(skb);
  82 send_skb_err:
  83         kfree_skb(skb);
  84         return NET_XMIT_DROP;
  85 }
  86
  87 /**
  88  * batadv_send_skb_to_orig - Lookup next-hop and transmit skb.
  89  * @skb: Packet to be transmitted.
  90  * @orig_node: Final destination of the packet.
  91  * @recv_if: Interface used when receiving the packet (can be NULL).
  92  *
  93  * Looks up the best next-hop towards the passed originator and passes the
  94  * skb on for preparation of MAC header. If the packet originated from this
  95  * host, NULL can be passed as recv_if and no interface alternating is
  96  * attempted.
  97  *
  98  * Returns NET_XMIT_SUCCESS on success, NET_XMIT_DROP on failure, or
  99  * NET_XMIT_POLICED if the skb is buffered for later transmit.
 100  */
 101 int 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         int ret = NET_XMIT_DROP;
 108
 109         /* batadv_find_router() increases neigh_nodes refcount if found. */
 110         neigh_node = batadv_find_router(bat_priv, orig_node, recv_if);
 111         if (!neigh_node)
 112                 return ret;
 113
 114         /* try to network code the packet, if it is received on an interface
 115          * (i.e. being forwarded). If the packet originates from this node or if
 116          * network coding fails, then send the packet as usual.
 117          */
 118         if (recv_if && batadv_nc_skb_forward(skb, neigh_node)) {
 119                 ret = NET_XMIT_POLICED;
 120         } else {
 121                 batadv_send_skb_packet(skb, neigh_node->if_incoming,
 122                                        neigh_node->addr);
 123                 ret = NET_XMIT_SUCCESS;
 124         }
 125
 126         batadv_neigh_node_free_ref(neigh_node);
 127
 128         return ret;
 129 }
 130
 131 void batadv_schedule_bat_ogm(struct batadv_hard_iface *hard_iface)
 132 {
 133         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 134
 135         if ((hard_iface->if_status == BATADV_IF_NOT_IN_USE) ||
 136             (hard_iface->if_status == BATADV_IF_TO_BE_REMOVED))
 137                 return;
 138
 139         /* the interface gets activated here to avoid race conditions between
 140          * the moment of activating the interface in
 141          * hardif_activate_interface() where the originator mac is set and
 142          * outdated packets (especially uninitialized mac addresses) in the
 143          * packet queue
 144          */
 145         if (hard_iface->if_status == BATADV_IF_TO_BE_ACTIVATED)
 146                 hard_iface->if_status = BATADV_IF_ACTIVE;
 147
 148         bat_priv->bat_algo_ops->bat_ogm_schedule(hard_iface);
 149 }
 150
 151 static void batadv_forw_packet_free(struct batadv_forw_packet *forw_packet)
 152 {
 153         if (forw_packet->skb)
 154                 kfree_skb(forw_packet->skb);
 155         if (forw_packet->if_incoming)
 156                 batadv_hardif_free_ref(forw_packet->if_incoming);
 157         kfree(forw_packet);
 158 }
 159
 160 static void
 161 _batadv_add_bcast_packet_to_list(struct batadv_priv *bat_priv,
 162                                  struct batadv_forw_packet *forw_packet,
 163                                  unsigned long send_time)
 164 {
 165         /* add new packet to packet list */
 166         spin_lock_bh(&bat_priv->forw_bcast_list_lock);
 167         hlist_add_head(&forw_packet->list, &bat_priv->forw_bcast_list);
 168         spin_unlock_bh(&bat_priv->forw_bcast_list_lock);
 169
 170         /* start timer for this packet */
 171         queue_delayed_work(batadv_event_workqueue, &forw_packet->delayed_work,
 172                            send_time);
 173 }
 174
 175 /* add a broadcast packet to the queue and setup timers. broadcast packets
 176  * are sent multiple times to increase probability for being received.
 177  *
 178  * This function returns NETDEV_TX_OK on success and NETDEV_TX_BUSY on
 179  * errors.
 180  *
 181  * The skb is not consumed, so the caller should make sure that the
 182  * skb is freed.
 183  */
 184 int batadv_add_bcast_packet_to_list(struct batadv_priv *bat_priv,
 185                                     const struct sk_buff *skb,
 186                                     unsigned long delay)
 187 {
 188         struct batadv_hard_iface *primary_if = NULL;
 189         struct batadv_forw_packet *forw_packet;
 190         struct batadv_bcast_packet *bcast_packet;
 191         struct sk_buff *newskb;
 192
 193         if (!batadv_atomic_dec_not_zero(&bat_priv->bcast_queue_left)) {
 194                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 195                            "bcast packet queue full\n");
 196                 goto out;
 197         }
 198
 199         primary_if = batadv_primary_if_get_selected(bat_priv);
 200         if (!primary_if)
 201                 goto out_and_inc;
 202
 203         forw_packet = kmalloc(sizeof(*forw_packet), GFP_ATOMIC);
 204
 205         if (!forw_packet)
 206                 goto out_and_inc;
 207
 208         newskb = skb_copy(skb, GFP_ATOMIC);
 209         if (!newskb)
 210                 goto packet_free;
 211
 212         /* as we have a copy now, it is safe to decrease the TTL */
 213         bcast_packet = (struct batadv_bcast_packet *)newskb->data;
 214         bcast_packet->header.ttl--;
 215
 216         skb_reset_mac_header(newskb);
 217
 218         forw_packet->skb = newskb;
 219         forw_packet->if_incoming = primary_if;
 220
 221         /* how often did we send the bcast packet ? */
 222         forw_packet->num_packets = 0;
 223
 224         INIT_DELAYED_WORK(&forw_packet->delayed_work,
 225                           batadv_send_outstanding_bcast_packet);
 226
 227         _batadv_add_bcast_packet_to_list(bat_priv, forw_packet, delay);
 228         return NETDEV_TX_OK;
 229
 230 packet_free:
 231         kfree(forw_packet);
 232 out_and_inc:
 233         atomic_inc(&bat_priv->bcast_queue_left);
 234 out:
 235         if (primary_if)
 236                 batadv_hardif_free_ref(primary_if);
 237         return NETDEV_TX_BUSY;
 238 }
 239
 240 static void batadv_send_outstanding_bcast_packet(struct work_struct *work)
 241 {
 242         struct batadv_hard_iface *hard_iface;
 243         struct delayed_work *delayed_work;
 244         struct batadv_forw_packet *forw_packet;
 245         struct sk_buff *skb1;
 246         struct net_device *soft_iface;
 247         struct batadv_priv *bat_priv;
 248
 249         delayed_work = container_of(work, struct delayed_work, work);
 250         forw_packet = container_of(delayed_work, struct batadv_forw_packet,
 251                                    delayed_work);
 252         soft_iface = forw_packet->if_incoming->soft_iface;
 253         bat_priv = netdev_priv(soft_iface);
 254
 255         spin_lock_bh(&bat_priv->forw_bcast_list_lock);
 256         hlist_del(&forw_packet->list);
 257         spin_unlock_bh(&bat_priv->forw_bcast_list_lock);
 258
 259         if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)
 260                 goto out;
 261
 262         if (batadv_dat_drop_broadcast_packet(bat_priv, forw_packet))
 263                 goto out;
 264
 265         /* rebroadcast packet */
 266         rcu_read_lock();
 267         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 268                 if (hard_iface->soft_iface != soft_iface)
 269                         continue;
 270
 271                 if (forw_packet->num_packets >= hard_iface->num_bcasts)
 272                         continue;
 273
 274                 /* send a copy of the saved skb */
 275                 skb1 = skb_clone(forw_packet->skb, GFP_ATOMIC);
 276                 if (skb1)
 277                         batadv_send_skb_packet(skb1, hard_iface,
 278                                                batadv_broadcast_addr);
 279         }
 280         rcu_read_unlock();
 281
 282         forw_packet->num_packets++;
 283
 284         /* if we still have some more bcasts to send */
 285         if (forw_packet->num_packets < BATADV_NUM_BCASTS_MAX) {
 286                 _batadv_add_bcast_packet_to_list(bat_priv, forw_packet,
 287                                                  msecs_to_jiffies(5));
 288                 return;
 289         }
 290
 291 out:
 292         batadv_forw_packet_free(forw_packet);
 293         atomic_inc(&bat_priv->bcast_queue_left);
 294 }
 295
 296 void batadv_send_outstanding_bat_ogm_packet(struct work_struct *work)
 297 {
 298         struct delayed_work *delayed_work;
 299         struct batadv_forw_packet *forw_packet;
 300         struct batadv_priv *bat_priv;
 301
 302         delayed_work = container_of(work, struct delayed_work, work);
 303         forw_packet = container_of(delayed_work, struct batadv_forw_packet,
 304                                    delayed_work);
 305         bat_priv = netdev_priv(forw_packet->if_incoming->soft_iface);
 306         spin_lock_bh(&bat_priv->forw_bat_list_lock);
 307         hlist_del(&forw_packet->list);
 308         spin_unlock_bh(&bat_priv->forw_bat_list_lock);
 309
 310         if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)
 311                 goto out;
 312
 313         bat_priv->bat_algo_ops->bat_ogm_emit(forw_packet);
 314
 315         /* we have to have at least one packet in the queue
 316          * to determine the queues wake up time unless we are
 317          * shutting down
 318          */
 319         if (forw_packet->own)
 320                 batadv_schedule_bat_ogm(forw_packet->if_incoming);
 321
 322 out:
 323         /* don't count own packet */
 324         if (!forw_packet->own)
 325                 atomic_inc(&bat_priv->batman_queue_left);
 326
 327         batadv_forw_packet_free(forw_packet);
 328 }
 329
 330 void
 331 batadv_purge_outstanding_packets(struct batadv_priv *bat_priv,
 332                                  const struct batadv_hard_iface *hard_iface)
 333 {
 334         struct batadv_forw_packet *forw_packet;
 335         struct hlist_node *safe_tmp_node;
 336         bool pending;
 337
 338         if (hard_iface)
 339                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 340                            "purge_outstanding_packets(): %s\n",
 341                            hard_iface->net_dev->name);
 342         else
 343                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 344                            "purge_outstanding_packets()\n");
 345
 346         /* free bcast list */
 347         spin_lock_bh(&bat_priv->forw_bcast_list_lock);
 348         hlist_for_each_entry_safe(forw_packet, safe_tmp_node,
 349                                   &bat_priv->forw_bcast_list, list) {
 350                 /* if purge_outstanding_packets() was called with an argument
 351                  * we delete only packets belonging to the given interface
 352                  */
 353                 if ((hard_iface) &&
 354                     (forw_packet->if_incoming != hard_iface))
 355                         continue;
 356
 357                 spin_unlock_bh(&bat_priv->forw_bcast_list_lock);
 358
 359                 /* batadv_send_outstanding_bcast_packet() will lock the list to
 360                  * delete the item from the list
 361                  */
 362                 pending = cancel_delayed_work_sync(&forw_packet->delayed_work);
 363                 spin_lock_bh(&bat_priv->forw_bcast_list_lock);
 364
 365                 if (pending) {
 366                         hlist_del(&forw_packet->list);
 367                         batadv_forw_packet_free(forw_packet);
 368                 }
 369         }
 370         spin_unlock_bh(&bat_priv->forw_bcast_list_lock);
 371
 372         /* free batman packet list */
 373         spin_lock_bh(&bat_priv->forw_bat_list_lock);
 374         hlist_for_each_entry_safe(forw_packet, safe_tmp_node,
 375                                   &bat_priv->forw_bat_list, list) {
 376                 /* if purge_outstanding_packets() was called with an argument
 377                  * we delete only packets belonging to the given interface
 378                  */
 379                 if ((hard_iface) &&
 380                     (forw_packet->if_incoming != hard_iface))
 381                         continue;
 382
 383                 spin_unlock_bh(&bat_priv->forw_bat_list_lock);
 384
 385                 /* send_outstanding_bat_packet() will lock the list to
 386                  * delete the item from the list
 387                  */
 388                 pending = cancel_delayed_work_sync(&forw_packet->delayed_work);
 389                 spin_lock_bh(&bat_priv->forw_bat_list_lock);
 390
 391                 if (pending) {
 392                         hlist_del(&forw_packet->list);
 393                         batadv_forw_packet_free(forw_packet);
 394                 }
 395         }
 396         spin_unlock_bh(&bat_priv->forw_bat_list_lock);
 397 }