net/batman-adv/send.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright (C) B.A.T.M.A.N. contributors:
   3  *
   4  * Marek Lindner, Simon Wunderlich
   5  */
   6
   7 #include "send.h"
   8 #include "main.h"
   9
  10 #include <linux/atomic.h>
  11 #include <linux/bug.h>
  12 #include <linux/byteorder/generic.h>
  13 #include <linux/errno.h>
  14 #include <linux/etherdevice.h>
  15 #include <linux/gfp.h>
  16 #include <linux/if.h>
  17 #include <linux/if_ether.h>
  18 #include <linux/jiffies.h>
  19 #include <linux/kernel.h>
  20 #include <linux/kref.h>
  21 #include <linux/list.h>
  22 #include <linux/netdevice.h>
  23 #include <linux/printk.h>
  24 #include <linux/rculist.h>
  25 #include <linux/rcupdate.h>
  26 #include <linux/skbuff.h>
  27 #include <linux/slab.h>
  28 #include <linux/spinlock.h>
  29 #include <linux/stddef.h>
  30 #include <linux/workqueue.h>
  31
  32 #include "distributed-arp-table.h"
  33 #include "fragmentation.h"
  34 #include "gateway_client.h"
  35 #include "hard-interface.h"
  36 #include "log.h"
  37 #include "network-coding.h"
  38 #include "originator.h"
  39 #include "routing.h"
  40 #include "soft-interface.h"
  41 #include "translation-table.h"
  42
  43 static void batadv_send_outstanding_bcast_packet(struct work_struct *work);
  44
  45 /**
  46  * batadv_send_skb_packet() - send an already prepared packet
  47  * @skb: the packet to send
  48  * @hard_iface: the interface to use to send the broadcast packet
  49  * @dst_addr: the payload destination
  50  *
  51  * Send out an already prepared packet to the given neighbor or broadcast it
  52  * using the specified interface. Either hard_iface or neigh_node must be not
  53  * NULL.
  54  * If neigh_node is NULL, then the packet is broadcasted using hard_iface,
  55  * otherwise it is sent as unicast to the given neighbor.
  56  *
  57  * Regardless of the return value, the skb is consumed.
  58  *
  59  * Return: A negative errno code is returned on a failure. A success does not
  60  * guarantee the frame will be transmitted as it may be dropped due
  61  * to congestion or traffic shaping.
  62  */
  63 int batadv_send_skb_packet(struct sk_buff *skb,
  64                            struct batadv_hard_iface *hard_iface,
  65                            const u8 *dst_addr)
  66 {
  67         struct batadv_priv *bat_priv;
  68         struct ethhdr *ethhdr;
  69         int ret;
  70
  71         bat_priv = netdev_priv(hard_iface->soft_iface);
  72
  73         if (hard_iface->if_status != BATADV_IF_ACTIVE)
  74                 goto send_skb_err;
  75
  76         if (unlikely(!hard_iface->net_dev))
  77                 goto send_skb_err;
  78
  79         if (!(hard_iface->net_dev->flags & IFF_UP)) {
  80                 pr_warn("Interface %s is not up - can't send packet via that interface!\n",
  81                         hard_iface->net_dev->name);
  82                 goto send_skb_err;
  83         }
  84
  85         /* push to the ethernet header. */
  86         if (batadv_skb_head_push(skb, ETH_HLEN) < 0)
  87                 goto send_skb_err;
  88
  89         skb_reset_mac_header(skb);
  90
  91         ethhdr = eth_hdr(skb);
  92         ether_addr_copy(ethhdr->h_source, hard_iface->net_dev->dev_addr);
  93         ether_addr_copy(ethhdr->h_dest, dst_addr);
  94         ethhdr->h_proto = htons(ETH_P_BATMAN);
  95
  96         skb_set_network_header(skb, ETH_HLEN);
  97         skb->protocol = htons(ETH_P_BATMAN);
  98
  99         skb->dev = hard_iface->net_dev;
 100
 101         /* Save a clone of the skb to use when decoding coded packets */
 102         batadv_nc_skb_store_for_decoding(bat_priv, skb);
 103
 104         /* dev_queue_xmit() returns a negative result on error.  However on
 105          * congestion and traffic shaping, it drops and returns NET_XMIT_DROP
 106          * (which is > 0). This will not be treated as an error.
 107          */
 108         ret = dev_queue_xmit(skb);
 109         return net_xmit_eval(ret);
 110 send_skb_err:
 111         kfree_skb(skb);
 112         return NET_XMIT_DROP;
 113 }
 114
 115 /**
 116  * batadv_send_broadcast_skb() - Send broadcast packet via hard interface
 117  * @skb: packet to be transmitted (with batadv header and no outer eth header)
 118  * @hard_iface: outgoing interface
 119  *
 120  * Return: A negative errno code is returned on a failure. A success does not
 121  * guarantee the frame will be transmitted as it may be dropped due
 122  * to congestion or traffic shaping.
 123  */
 124 int batadv_send_broadcast_skb(struct sk_buff *skb,
 125                               struct batadv_hard_iface *hard_iface)
 126 {
 127         return batadv_send_skb_packet(skb, hard_iface, batadv_broadcast_addr);
 128 }
 129
 130 /**
 131  * batadv_send_unicast_skb() - Send unicast packet to neighbor
 132  * @skb: packet to be transmitted (with batadv header and no outer eth header)
 133  * @neigh: neighbor which is used as next hop to destination
 134  *
 135  * Return: A negative errno code is returned on a failure. A success does not
 136  * guarantee the frame will be transmitted as it may be dropped due
 137  * to congestion or traffic shaping.
 138  */
 139 int batadv_send_unicast_skb(struct sk_buff *skb,
 140                             struct batadv_neigh_node *neigh)
 141 {
 142 #ifdef CONFIG_BATMAN_ADV_BATMAN_V
 143         struct batadv_hardif_neigh_node *hardif_neigh;
 144 #endif
 145         int ret;
 146
 147         ret = batadv_send_skb_packet(skb, neigh->if_incoming, neigh->addr);
 148
 149 #ifdef CONFIG_BATMAN_ADV_BATMAN_V
 150         hardif_neigh = batadv_hardif_neigh_get(neigh->if_incoming, neigh->addr);
 151
 152         if (hardif_neigh && ret != NET_XMIT_DROP)
 153                 hardif_neigh->bat_v.last_unicast_tx = jiffies;
 154
 155         batadv_hardif_neigh_put(hardif_neigh);
 156 #endif
 157
 158         return ret;
 159 }
 160
 161 /**
 162  * batadv_send_skb_to_orig() - Lookup next-hop and transmit skb.
 163  * @skb: Packet to be transmitted.
 164  * @orig_node: Final destination of the packet.
 165  * @recv_if: Interface used when receiving the packet (can be NULL).
 166  *
 167  * Looks up the best next-hop towards the passed originator and passes the
 168  * skb on for preparation of MAC header. If the packet originated from this
 169  * host, NULL can be passed as recv_if and no interface alternating is
 170  * attempted.
 171  *
 172  * Return: negative errno code on a failure, -EINPROGRESS if the skb is
 173  * buffered for later transmit or the NET_XMIT status returned by the
 174  * lower routine if the packet has been passed down.
 175  */
 176 int batadv_send_skb_to_orig(struct sk_buff *skb,
 177                             struct batadv_orig_node *orig_node,
 178                             struct batadv_hard_iface *recv_if)
 179 {
 180         struct batadv_priv *bat_priv = orig_node->bat_priv;
 181         struct batadv_neigh_node *neigh_node;
 182         int ret;
 183
 184         /* batadv_find_router() increases neigh_nodes refcount if found. */
 185         neigh_node = batadv_find_router(bat_priv, orig_node, recv_if);
 186         if (!neigh_node) {
 187                 ret = -EINVAL;
 188                 goto free_skb;
 189         }
 190
 191         /* Check if the skb is too large to send in one piece and fragment
 192          * it if needed.
 193          */
 194         if (atomic_read(&bat_priv->fragmentation) &&
 195             skb->len > neigh_node->if_incoming->net_dev->mtu) {
 196                 /* Fragment and send packet. */
 197                 ret = batadv_frag_send_packet(skb, orig_node, neigh_node);
 198                 /* skb was consumed */
 199                 skb = NULL;
 200
 201                 goto put_neigh_node;
 202         }
 203
 204         /* try to network code the packet, if it is received on an interface
 205          * (i.e. being forwarded). If the packet originates from this node or if
 206          * network coding fails, then send the packet as usual.
 207          */
 208         if (recv_if && batadv_nc_skb_forward(skb, neigh_node))
 209                 ret = -EINPROGRESS;
 210         else
 211                 ret = batadv_send_unicast_skb(skb, neigh_node);
 212
 213         /* skb was consumed */
 214         skb = NULL;
 215
 216 put_neigh_node:
 217         batadv_neigh_node_put(neigh_node);
 218 free_skb:
 219         kfree_skb(skb);
 220
 221         return ret;
 222 }
 223
 224 /**
 225  * batadv_send_skb_push_fill_unicast() - extend the buffer and initialize the
 226  *  common fields for unicast packets
 227  * @skb: the skb carrying the unicast header to initialize
 228  * @hdr_size: amount of bytes to push at the beginning of the skb
 229  * @orig_node: the destination node
 230  *
 231  * Return: false if the buffer extension was not possible or true otherwise.
 232  */
 233 static bool
 234 batadv_send_skb_push_fill_unicast(struct sk_buff *skb, int hdr_size,
 235                                   struct batadv_orig_node *orig_node)
 236 {
 237         struct batadv_unicast_packet *unicast_packet;
 238         u8 ttvn = (u8)atomic_read(&orig_node->last_ttvn);
 239
 240         if (batadv_skb_head_push(skb, hdr_size) < 0)
 241                 return false;
 242
 243         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 244         unicast_packet->version = BATADV_COMPAT_VERSION;
 245         /* batman packet type: unicast */
 246         unicast_packet->packet_type = BATADV_UNICAST;
 247         /* set unicast ttl */
 248         unicast_packet->ttl = BATADV_TTL;
 249         /* copy the destination for faster routing */
 250         ether_addr_copy(unicast_packet->dest, orig_node->orig);
 251         /* set the destination tt version number */
 252         unicast_packet->ttvn = ttvn;
 253
 254         return true;
 255 }
 256
 257 /**
 258  * batadv_send_skb_prepare_unicast() - encapsulate an skb with a unicast header
 259  * @skb: the skb containing the payload to encapsulate
 260  * @orig_node: the destination node
 261  *
 262  * Return: false if the payload could not be encapsulated or true otherwise.
 263  */
 264 static bool batadv_send_skb_prepare_unicast(struct sk_buff *skb,
 265                                             struct batadv_orig_node *orig_node)
 266 {
 267         size_t uni_size = sizeof(struct batadv_unicast_packet);
 268
 269         return batadv_send_skb_push_fill_unicast(skb, uni_size, orig_node);
 270 }
 271
 272 /**
 273  * batadv_send_skb_prepare_unicast_4addr() - encapsulate an skb with a
 274  *  unicast 4addr header
 275  * @bat_priv: the bat priv with all the soft interface information
 276  * @skb: the skb containing the payload to encapsulate
 277  * @orig: the destination node
 278  * @packet_subtype: the unicast 4addr packet subtype to use
 279  *
 280  * Return: false if the payload could not be encapsulated or true otherwise.
 281  */
 282 bool batadv_send_skb_prepare_unicast_4addr(struct batadv_priv *bat_priv,
 283                                            struct sk_buff *skb,
 284                                            struct batadv_orig_node *orig,
 285                                            int packet_subtype)
 286 {
 287         struct batadv_hard_iface *primary_if;
 288         struct batadv_unicast_4addr_packet *uc_4addr_packet;
 289         bool ret = false;
 290
 291         primary_if = batadv_primary_if_get_selected(bat_priv);
 292         if (!primary_if)
 293                 goto out;
 294
 295         /* Pull the header space and fill the unicast_packet substructure.
 296          * We can do that because the first member of the uc_4addr_packet
 297          * is of type struct unicast_packet
 298          */
 299         if (!batadv_send_skb_push_fill_unicast(skb, sizeof(*uc_4addr_packet),
 300                                                orig))
 301                 goto out;
 302
 303         uc_4addr_packet = (struct batadv_unicast_4addr_packet *)skb->data;
 304         uc_4addr_packet->u.packet_type = BATADV_UNICAST_4ADDR;
 305         ether_addr_copy(uc_4addr_packet->src, primary_if->net_dev->dev_addr);
 306         uc_4addr_packet->subtype = packet_subtype;
 307         uc_4addr_packet->reserved = 0;
 308
 309         ret = true;
 310 out:
 311         batadv_hardif_put(primary_if);
 312         return ret;
 313 }
 314
 315 /**
 316  * batadv_send_skb_unicast() - encapsulate and send an skb via unicast
 317  * @bat_priv: the bat priv with all the soft interface information
 318  * @skb: payload to send
 319  * @packet_type: the batman unicast packet type to use
 320  * @packet_subtype: the unicast 4addr packet subtype (only relevant for unicast
 321  *  4addr packets)
 322  * @orig_node: the originator to send the packet to
 323  * @vid: the vid to be used to search the translation table
 324  *
 325  * Wrap the given skb into a batman-adv unicast or unicast-4addr header
 326  * depending on whether BATADV_UNICAST or BATADV_UNICAST_4ADDR was supplied
 327  * as packet_type. Then send this frame to the given orig_node.
 328  *
 329  * Return: NET_XMIT_DROP in case of error or NET_XMIT_SUCCESS otherwise.
 330  */
 331 int batadv_send_skb_unicast(struct batadv_priv *bat_priv,
 332                             struct sk_buff *skb, int packet_type,
 333                             int packet_subtype,
 334                             struct batadv_orig_node *orig_node,
 335                             unsigned short vid)
 336 {
 337         struct batadv_unicast_packet *unicast_packet;
 338         struct ethhdr *ethhdr;
 339         int ret = NET_XMIT_DROP;
 340
 341         if (!orig_node)
 342                 goto out;
 343
 344         switch (packet_type) {
 345         case BATADV_UNICAST:
 346                 if (!batadv_send_skb_prepare_unicast(skb, orig_node))
 347                         goto out;
 348                 break;
 349         case BATADV_UNICAST_4ADDR:
 350                 if (!batadv_send_skb_prepare_unicast_4addr(bat_priv, skb,
 351                                                            orig_node,
 352                                                            packet_subtype))
 353                         goto out;
 354                 break;
 355         default:
 356                 /* this function supports UNICAST and UNICAST_4ADDR only. It
 357                  * should never be invoked with any other packet type
 358                  */
 359                 goto out;
 360         }
 361
 362         /* skb->data might have been reallocated by
 363          * batadv_send_skb_prepare_unicast{,_4addr}()
 364          */
 365         ethhdr = eth_hdr(skb);
 366         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 367
 368         /* inform the destination node that we are still missing a correct route
 369          * for this client. The destination will receive this packet and will
 370          * try to reroute it because the ttvn contained in the header is less
 371          * than the current one
 372          */
 373         if (batadv_tt_global_client_is_roaming(bat_priv, ethhdr->h_dest, vid))
 374                 unicast_packet->ttvn = unicast_packet->ttvn - 1;
 375
 376         ret = batadv_send_skb_to_orig(skb, orig_node, NULL);
 377          /* skb was consumed */
 378         skb = NULL;
 379
 380 out:
 381         kfree_skb(skb);
 382         return ret;
 383 }
 384
 385 /**
 386  * batadv_send_skb_via_tt_generic() - send an skb via TT lookup
 387  * @bat_priv: the bat priv with all the soft interface information
 388  * @skb: payload to send
 389  * @packet_type: the batman unicast packet type to use
 390  * @packet_subtype: the unicast 4addr packet subtype (only relevant for unicast
 391  *  4addr packets)
 392  * @dst_hint: can be used to override the destination contained in the skb
 393  * @vid: the vid to be used to search the translation table
 394  *
 395  * Look up the recipient node for the destination address in the ethernet
 396  * header via the translation table. Wrap the given skb into a batman-adv
 397  * unicast or unicast-4addr header depending on whether BATADV_UNICAST or
 398  * BATADV_UNICAST_4ADDR was supplied as packet_type. Then send this frame
 399  * to the according destination node.
 400  *
 401  * Return: NET_XMIT_DROP in case of error or NET_XMIT_SUCCESS otherwise.
 402  */
 403 int batadv_send_skb_via_tt_generic(struct batadv_priv *bat_priv,
 404                                    struct sk_buff *skb, int packet_type,
 405                                    int packet_subtype, u8 *dst_hint,
 406                                    unsigned short vid)
 407 {
 408         struct ethhdr *ethhdr = (struct ethhdr *)skb->data;
 409         struct batadv_orig_node *orig_node;
 410         u8 *src, *dst;
 411         int ret;
 412
 413         src = ethhdr->h_source;
 414         dst = ethhdr->h_dest;
 415
 416         /* if we got an hint! let's send the packet to this client (if any) */
 417         if (dst_hint) {
 418                 src = NULL;
 419                 dst = dst_hint;
 420         }
 421         orig_node = batadv_transtable_search(bat_priv, src, dst, vid);
 422
 423         ret = batadv_send_skb_unicast(bat_priv, skb, packet_type,
 424                                       packet_subtype, orig_node, vid);
 425
 426         batadv_orig_node_put(orig_node);
 427
 428         return ret;
 429 }
 430
 431 /**
 432  * batadv_send_skb_via_gw() - send an skb via gateway lookup
 433  * @bat_priv: the bat priv with all the soft interface information
 434  * @skb: payload to send
 435  * @vid: the vid to be used to search the translation table
 436  *
 437  * Look up the currently selected gateway. Wrap the given skb into a batman-adv
 438  * unicast header and send this frame to this gateway node.
 439  *
 440  * Return: NET_XMIT_DROP in case of error or NET_XMIT_SUCCESS otherwise.
 441  */
 442 int batadv_send_skb_via_gw(struct batadv_priv *bat_priv, struct sk_buff *skb,
 443                            unsigned short vid)
 444 {
 445         struct batadv_orig_node *orig_node;
 446         int ret;
 447
 448         orig_node = batadv_gw_get_selected_orig(bat_priv);
 449         ret = batadv_send_skb_unicast(bat_priv, skb, BATADV_UNICAST_4ADDR,
 450                                       BATADV_P_DATA, orig_node, vid);
 451
 452         batadv_orig_node_put(orig_node);
 453
 454         return ret;
 455 }
 456
 457 /**
 458  * batadv_forw_packet_free() - free a forwarding packet
 459  * @forw_packet: The packet to free
 460  * @dropped: whether the packet is freed because is dropped
 461  *
 462  * This frees a forwarding packet and releases any resources it might
 463  * have claimed.
 464  */
 465 void batadv_forw_packet_free(struct batadv_forw_packet *forw_packet,
 466                              bool dropped)
 467 {
 468         if (dropped)
 469                 kfree_skb(forw_packet->skb);
 470         else
 471                 consume_skb(forw_packet->skb);
 472
 473         batadv_hardif_put(forw_packet->if_incoming);
 474         batadv_hardif_put(forw_packet->if_outgoing);
 475         if (forw_packet->queue_left)
 476                 atomic_inc(forw_packet->queue_left);
 477         kfree(forw_packet);
 478 }
 479
 480 /**
 481  * batadv_forw_packet_alloc() - allocate a forwarding packet
 482  * @if_incoming: The (optional) if_incoming to be grabbed
 483  * @if_outgoing: The (optional) if_outgoing to be grabbed
 484  * @queue_left: The (optional) queue counter to decrease
 485  * @bat_priv: The bat_priv for the mesh of this forw_packet
 486  * @skb: The raw packet this forwarding packet shall contain
 487  *
 488  * Allocates a forwarding packet and tries to get a reference to the
 489  * (optional) if_incoming, if_outgoing and queue_left. If queue_left
 490  * is NULL then bat_priv is optional, too.
 491  *
 492  * Return: An allocated forwarding packet on success, NULL otherwise.
 493  */
 494 struct batadv_forw_packet *
 495 batadv_forw_packet_alloc(struct batadv_hard_iface *if_incoming,
 496                          struct batadv_hard_iface *if_outgoing,
 497                          atomic_t *queue_left,
 498                          struct batadv_priv *bat_priv,
 499                          struct sk_buff *skb)
 500 {
 501         struct batadv_forw_packet *forw_packet;
 502         const char *qname;
 503
 504         if (queue_left && !batadv_atomic_dec_not_zero(queue_left)) {
 505                 qname = "unknown";
 506
 507                 if (queue_left == &bat_priv->bcast_queue_left)
 508                         qname = "bcast";
 509
 510                 if (queue_left == &bat_priv->batman_queue_left)
 511                         qname = "batman";
 512
 513                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 514                            "%s queue is full\n", qname);
 515
 516                 return NULL;
 517         }
 518
 519         forw_packet = kmalloc(sizeof(*forw_packet), GFP_ATOMIC);
 520         if (!forw_packet)
 521                 goto err;
 522
 523         if (if_incoming)
 524                 kref_get(&if_incoming->refcount);
 525
 526         if (if_outgoing)
 527                 kref_get(&if_outgoing->refcount);
 528
 529         INIT_HLIST_NODE(&forw_packet->list);
 530         INIT_HLIST_NODE(&forw_packet->cleanup_list);
 531         forw_packet->skb = skb;
 532         forw_packet->queue_left = queue_left;
 533         forw_packet->if_incoming = if_incoming;
 534         forw_packet->if_outgoing = if_outgoing;
 535         forw_packet->num_packets = 0;
 536
 537         return forw_packet;
 538
 539 err:
 540         if (queue_left)
 541                 atomic_inc(queue_left);
 542
 543         return NULL;
 544 }
 545
 546 /**
 547  * batadv_forw_packet_was_stolen() - check whether someone stole this packet
 548  * @forw_packet: the forwarding packet to check
 549  *
 550  * This function checks whether the given forwarding packet was claimed by
 551  * someone else for free().
 552  *
 553  * Return: True if someone stole it, false otherwise.
 554  */
 555 static bool
 556 batadv_forw_packet_was_stolen(struct batadv_forw_packet *forw_packet)
 557 {
 558         return !hlist_unhashed(&forw_packet->cleanup_list);
 559 }
 560
 561 /**
 562  * batadv_forw_packet_steal() - claim a forw_packet for free()
 563  * @forw_packet: the forwarding packet to steal
 564  * @lock: a key to the store to steal from (e.g. forw_{bat,bcast}_list_lock)
 565  *
 566  * This function tries to steal a specific forw_packet from global
 567  * visibility for the purpose of getting it for free(). That means
 568  * the caller is *not* allowed to requeue it afterwards.
 569  *
 570  * Return: True if stealing was successful. False if someone else stole it
 571  * before us.
 572  */
 573 bool batadv_forw_packet_steal(struct batadv_forw_packet *forw_packet,
 574                               spinlock_t *lock)
 575 {
 576         /* did purging routine steal it earlier? */
 577         spin_lock_bh(lock);
 578         if (batadv_forw_packet_was_stolen(forw_packet)) {
 579                 spin_unlock_bh(lock);
 580                 return false;
 581         }
 582
 583         hlist_del_init(&forw_packet->list);
 584
 585         /* Just to spot misuse of this function */
 586         hlist_add_fake(&forw_packet->cleanup_list);
 587
 588         spin_unlock_bh(lock);
 589         return true;
 590 }
 591
 592 /**
 593  * batadv_forw_packet_list_steal() - claim a list of forward packets for free()
 594  * @forw_list: the to be stolen forward packets
 595  * @cleanup_list: a backup pointer, to be able to dispose the packet later
 596  * @hard_iface: the interface to steal forward packets from
 597  *
 598  * This function claims responsibility to free any forw_packet queued on the
 599  * given hard_iface. If hard_iface is NULL forwarding packets on all hard
 600  * interfaces will be claimed.
 601  *
 602  * The packets are being moved from the forw_list to the cleanup_list. This
 603  * makes it possible for already running threads to notice the claim.
 604  */
 605 static void
 606 batadv_forw_packet_list_steal(struct hlist_head *forw_list,
 607                               struct hlist_head *cleanup_list,
 608                               const struct batadv_hard_iface *hard_iface)
 609 {
 610         struct batadv_forw_packet *forw_packet;
 611         struct hlist_node *safe_tmp_node;
 612
 613         hlist_for_each_entry_safe(forw_packet, safe_tmp_node,
 614                                   forw_list, list) {
 615                 /* if purge_outstanding_packets() was called with an argument
 616                  * we delete only packets belonging to the given interface
 617                  */
 618                 if (hard_iface &&
 619                     forw_packet->if_incoming != hard_iface &&
 620                     forw_packet->if_outgoing != hard_iface)
 621                         continue;
 622
 623                 hlist_del(&forw_packet->list);
 624                 hlist_add_head(&forw_packet->cleanup_list, cleanup_list);
 625         }
 626 }
 627
 628 /**
 629  * batadv_forw_packet_list_free() - free a list of forward packets
 630  * @head: a list of to be freed forw_packets
 631  *
 632  * This function cancels the scheduling of any packet in the provided list,
 633  * waits for any possibly running packet forwarding thread to finish and
 634  * finally, safely frees this forward packet.
 635  *
 636  * This function might sleep.
 637  */
 638 static void batadv_forw_packet_list_free(struct hlist_head *head)
 639 {
 640         struct batadv_forw_packet *forw_packet;
 641         struct hlist_node *safe_tmp_node;
 642
 643         hlist_for_each_entry_safe(forw_packet, safe_tmp_node, head,
 644                                   cleanup_list) {
 645                 cancel_delayed_work_sync(&forw_packet->delayed_work);
 646
 647                 hlist_del(&forw_packet->cleanup_list);
 648                 batadv_forw_packet_free(forw_packet, true);
 649         }
 650 }
 651
 652 /**
 653  * batadv_forw_packet_queue() - try to queue a forwarding packet
 654  * @forw_packet: the forwarding packet to queue
 655  * @lock: a key to the store (e.g. forw_{bat,bcast}_list_lock)
 656  * @head: the shelve to queue it on (e.g. forw_{bat,bcast}_list)
 657  * @send_time: timestamp (jiffies) when the packet is to be sent
 658  *
 659  * This function tries to (re)queue a forwarding packet. Requeuing
 660  * is prevented if the according interface is shutting down
 661  * (e.g. if batadv_forw_packet_list_steal() was called for this
 662  * packet earlier).
 663  *
 664  * Calling batadv_forw_packet_queue() after a call to
 665  * batadv_forw_packet_steal() is forbidden!
 666  *
 667  * Caller needs to ensure that forw_packet->delayed_work was initialized.
 668  */
 669 static void batadv_forw_packet_queue(struct batadv_forw_packet *forw_packet,
 670                                      spinlock_t *lock, struct hlist_head *head,
 671                                      unsigned long send_time)
 672 {
 673         spin_lock_bh(lock);
 674
 675         /* did purging routine steal it from us? */
 676         if (batadv_forw_packet_was_stolen(forw_packet)) {
 677                 /* If you got it for free() without trouble, then
 678                  * don't get back into the queue after stealing...
 679                  */
 680                 WARN_ONCE(hlist_fake(&forw_packet->cleanup_list),
 681                           "Requeuing after batadv_forw_packet_steal() not allowed!\n");
 682
 683                 spin_unlock_bh(lock);
 684                 return;
 685         }
 686
 687         hlist_del_init(&forw_packet->list);
 688         hlist_add_head(&forw_packet->list, head);
 689
 690         queue_delayed_work(batadv_event_workqueue,
 691                            &forw_packet->delayed_work,
 692                            send_time - jiffies);
 693         spin_unlock_bh(lock);
 694 }
 695
 696 /**
 697  * batadv_forw_packet_bcast_queue() - try to queue a broadcast packet
 698  * @bat_priv: the bat priv with all the soft interface information
 699  * @forw_packet: the forwarding packet to queue
 700  * @send_time: timestamp (jiffies) when the packet is to be sent
 701  *
 702  * This function tries to (re)queue a broadcast packet.
 703  *
 704  * Caller needs to ensure that forw_packet->delayed_work was initialized.
 705  */
 706 static void
 707 batadv_forw_packet_bcast_queue(struct batadv_priv *bat_priv,
 708                                struct batadv_forw_packet *forw_packet,
 709                                unsigned long send_time)
 710 {
 711         batadv_forw_packet_queue(forw_packet, &bat_priv->forw_bcast_list_lock,
 712                                  &bat_priv->forw_bcast_list, send_time);
 713 }
 714
 715 /**
 716  * batadv_forw_packet_ogmv1_queue() - try to queue an OGMv1 packet
 717  * @bat_priv: the bat priv with all the soft interface information
 718  * @forw_packet: the forwarding packet to queue
 719  * @send_time: timestamp (jiffies) when the packet is to be sent
 720  *
 721  * This function tries to (re)queue an OGMv1 packet.
 722  *
 723  * Caller needs to ensure that forw_packet->delayed_work was initialized.
 724  */
 725 void batadv_forw_packet_ogmv1_queue(struct batadv_priv *bat_priv,
 726                                     struct batadv_forw_packet *forw_packet,
 727                                     unsigned long send_time)
 728 {
 729         batadv_forw_packet_queue(forw_packet, &bat_priv->forw_bat_list_lock,
 730                                  &bat_priv->forw_bat_list, send_time);
 731 }
 732
 733 /**
 734  * batadv_forw_bcast_packet_to_list() - queue broadcast packet for transmissions
 735  * @bat_priv: the bat priv with all the soft interface information
 736  * @skb: broadcast packet to add
 737  * @delay: number of jiffies to wait before sending
 738  * @own_packet: true if it is a self-generated broadcast packet
 739  * @if_in: the interface where the packet was received on
 740  * @if_out: the outgoing interface to queue on
 741  *
 742  * Adds a broadcast packet to the queue and sets up timers. Broadcast packets
 743  * are sent multiple times to increase probability for being received.
 744  *
 745  * This call clones the given skb, hence the caller needs to take into
 746  * account that the data segment of the original skb might not be
 747  * modifiable anymore.
 748  *
 749  * Return: NETDEV_TX_OK on success and NETDEV_TX_BUSY on errors.
 750  */
 751 static int batadv_forw_bcast_packet_to_list(struct batadv_priv *bat_priv,
 752                                             struct sk_buff *skb,
 753                                             unsigned long delay,
 754                                             bool own_packet,
 755                                             struct batadv_hard_iface *if_in,
 756                                             struct batadv_hard_iface *if_out)
 757 {
 758         struct batadv_forw_packet *forw_packet;
 759         unsigned long send_time = jiffies;
 760         struct sk_buff *newskb;
 761
 762         newskb = skb_clone(skb, GFP_ATOMIC);
 763         if (!newskb)
 764                 goto err;
 765
 766         forw_packet = batadv_forw_packet_alloc(if_in, if_out,
 767                                                &bat_priv->bcast_queue_left,
 768                                                bat_priv, newskb);
 769         if (!forw_packet)
 770                 goto err_packet_free;
 771
 772         forw_packet->own = own_packet;
 773
 774         INIT_DELAYED_WORK(&forw_packet->delayed_work,
 775                           batadv_send_outstanding_bcast_packet);
 776
 777         send_time += delay ? delay : msecs_to_jiffies(5);
 778
 779         batadv_forw_packet_bcast_queue(bat_priv, forw_packet, send_time);
 780         return NETDEV_TX_OK;
 781
 782 err_packet_free:
 783         kfree_skb(newskb);
 784 err:
 785         return NETDEV_TX_BUSY;
 786 }
 787
 788 /**
 789  * batadv_forw_bcast_packet_if() - forward and queue a broadcast packet
 790  * @bat_priv: the bat priv with all the soft interface information
 791  * @skb: broadcast packet to add
 792  * @delay: number of jiffies to wait before sending
 793  * @own_packet: true if it is a self-generated broadcast packet
 794  * @if_in: the interface where the packet was received on
 795  * @if_out: the outgoing interface to forward to
 796  *
 797  * Transmits a broadcast packet on the specified interface either immediately
 798  * or if a delay is given after that. Furthermore, queues additional
 799  * retransmissions if this interface is a wireless one.
 800  *
 801  * This call clones the given skb, hence the caller needs to take into
 802  * account that the data segment of the original skb might not be
 803  * modifiable anymore.
 804  *
 805  * Return: NETDEV_TX_OK on success and NETDEV_TX_BUSY on errors.
 806  */
 807 static int batadv_forw_bcast_packet_if(struct batadv_priv *bat_priv,
 808                                        struct sk_buff *skb,
 809                                        unsigned long delay,
 810                                        bool own_packet,
 811                                        struct batadv_hard_iface *if_in,
 812                                        struct batadv_hard_iface *if_out)
 813 {
 814         unsigned int num_bcasts = if_out->num_bcasts;
 815         struct sk_buff *newskb;
 816         int ret = NETDEV_TX_OK;
 817
 818         if (!delay) {
 819                 newskb = skb_clone(skb, GFP_ATOMIC);
 820                 if (!newskb)
 821                         return NETDEV_TX_BUSY;
 822
 823                 batadv_send_broadcast_skb(newskb, if_out);
 824                 num_bcasts--;
 825         }
 826
 827         /* delayed broadcast or rebroadcasts? */
 828         if (num_bcasts >= 1) {
 829                 BATADV_SKB_CB(skb)->num_bcasts = num_bcasts;
 830
 831                 ret = batadv_forw_bcast_packet_to_list(bat_priv, skb, delay,
 832                                                        own_packet, if_in,
 833                                                        if_out);
 834         }
 835
 836         return ret;
 837 }
 838
 839 /**
 840  * batadv_send_no_broadcast() - check whether (re)broadcast is necessary
 841  * @bat_priv: the bat priv with all the soft interface information
 842  * @skb: broadcast packet to check
 843  * @own_packet: true if it is a self-generated broadcast packet
 844  * @if_out: the outgoing interface checked and considered for (re)broadcast
 845  *
 846  * Return: False if a packet needs to be (re)broadcasted on the given interface,
 847  * true otherwise.
 848  */
 849 static bool batadv_send_no_broadcast(struct batadv_priv *bat_priv,
 850                                      struct sk_buff *skb, bool own_packet,
 851                                      struct batadv_hard_iface *if_out)
 852 {
 853         struct batadv_hardif_neigh_node *neigh_node = NULL;
 854         struct batadv_bcast_packet *bcast_packet;
 855         u8 *orig_neigh;
 856         u8 *neigh_addr;
 857         char *type;
 858         int ret;
 859
 860         if (!own_packet) {
 861                 neigh_addr = eth_hdr(skb)->h_source;
 862                 neigh_node = batadv_hardif_neigh_get(if_out,
 863                                                      neigh_addr);
 864         }
 865
 866         bcast_packet = (struct batadv_bcast_packet *)skb->data;
 867         orig_neigh = neigh_node ? neigh_node->orig : NULL;
 868
 869         ret = batadv_hardif_no_broadcast(if_out, bcast_packet->orig,
 870                                          orig_neigh);
 871
 872         batadv_hardif_neigh_put(neigh_node);
 873
 874         /* ok, may broadcast */
 875         if (!ret)
 876                 return false;
 877
 878         /* no broadcast */
 879         switch (ret) {
 880         case BATADV_HARDIF_BCAST_NORECIPIENT:
 881                 type = "no neighbor";
 882                 break;
 883         case BATADV_HARDIF_BCAST_DUPFWD:
 884                 type = "single neighbor is source";
 885                 break;
 886         case BATADV_HARDIF_BCAST_DUPORIG:
 887                 type = "single neighbor is originator";
 888                 break;
 889         default:
 890                 type = "unknown";
 891         }
 892
 893         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 894                    "BCAST packet from orig %pM on %s suppressed: %s\n",
 895                    bcast_packet->orig,
 896                    if_out->net_dev->name, type);
 897
 898         return true;
 899 }
 900
 901 /**
 902  * __batadv_forw_bcast_packet() - forward and queue a broadcast packet
 903  * @bat_priv: the bat priv with all the soft interface information
 904  * @skb: broadcast packet to add
 905  * @delay: number of jiffies to wait before sending
 906  * @own_packet: true if it is a self-generated broadcast packet
 907  *
 908  * Transmits a broadcast packet either immediately or if a delay is given
 909  * after that. Furthermore, queues additional retransmissions on wireless
 910  * interfaces.
 911  *
 912  * This call clones the given skb, hence the caller needs to take into
 913  * account that the data segment of the given skb might not be
 914  * modifiable anymore.
 915  *
 916  * Return: NETDEV_TX_OK on success and NETDEV_TX_BUSY on errors.
 917  */
 918 static int __batadv_forw_bcast_packet(struct batadv_priv *bat_priv,
 919                                       struct sk_buff *skb,
 920                                       unsigned long delay,
 921                                       bool own_packet)
 922 {
 923         struct batadv_hard_iface *hard_iface;
 924         struct batadv_hard_iface *primary_if;
 925         int ret = NETDEV_TX_OK;
 926
 927         primary_if = batadv_primary_if_get_selected(bat_priv);
 928         if (!primary_if)
 929                 return NETDEV_TX_BUSY;
 930
 931         rcu_read_lock();
 932         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 933                 if (hard_iface->soft_iface != bat_priv->soft_iface)
 934                         continue;
 935
 936                 if (!kref_get_unless_zero(&hard_iface->refcount))
 937                         continue;
 938
 939                 if (batadv_send_no_broadcast(bat_priv, skb, own_packet,
 940                                              hard_iface)) {
 941                         batadv_hardif_put(hard_iface);
 942                         continue;
 943                 }
 944
 945                 ret = batadv_forw_bcast_packet_if(bat_priv, skb, delay,
 946                                                   own_packet, primary_if,
 947                                                   hard_iface);
 948                 batadv_hardif_put(hard_iface);
 949
 950                 if (ret == NETDEV_TX_BUSY)
 951                         break;
 952         }
 953         rcu_read_unlock();
 954
 955         batadv_hardif_put(primary_if);
 956         return ret;
 957 }
 958
 959 /**
 960  * batadv_forw_bcast_packet() - forward and queue a broadcast packet
 961  * @bat_priv: the bat priv with all the soft interface information
 962  * @skb: broadcast packet to add
 963  * @delay: number of jiffies to wait before sending
 964  * @own_packet: true if it is a self-generated broadcast packet
 965  *
 966  * Transmits a broadcast packet either immediately or if a delay is given
 967  * after that. Furthermore, queues additional retransmissions on wireless
 968  * interfaces.
 969  *
 970  * Return: NETDEV_TX_OK on success and NETDEV_TX_BUSY on errors.
 971  */
 972 int batadv_forw_bcast_packet(struct batadv_priv *bat_priv,
 973                              struct sk_buff *skb,
 974                              unsigned long delay,
 975                              bool own_packet)
 976 {
 977         return __batadv_forw_bcast_packet(bat_priv, skb, delay, own_packet);
 978 }
 979
 980 /**
 981  * batadv_send_bcast_packet() - send and queue a broadcast packet
 982  * @bat_priv: the bat priv with all the soft interface information
 983  * @skb: broadcast packet to add
 984  * @delay: number of jiffies to wait before sending
 985  * @own_packet: true if it is a self-generated broadcast packet
 986  *
 987  * Transmits a broadcast packet either immediately or if a delay is given
 988  * after that. Furthermore, queues additional retransmissions on wireless
 989  * interfaces.
 990  *
 991  * Consumes the provided skb.
 992  */
 993 void batadv_send_bcast_packet(struct batadv_priv *bat_priv,
 994                               struct sk_buff *skb,
 995                               unsigned long delay,
 996                               bool own_packet)
 997 {
 998         __batadv_forw_bcast_packet(bat_priv, skb, delay, own_packet);
 999         consume_skb(skb);
1000 }
1001
1002 /**
1003  * batadv_forw_packet_bcasts_left() - check if a retransmission is necessary
1004  * @forw_packet: the forwarding packet to check
1005  *
1006  * Checks whether a given packet has any (re)transmissions left on the provided
1007  * interface.
1008  *
1009  * hard_iface may be NULL: In that case the number of transmissions this skb had
1010  * so far is compared with the maximum amount of retransmissions independent of
1011  * any interface instead.
1012  *
1013  * Return: True if (re)transmissions are left, false otherwise.
1014  */
1015 static bool
1016 batadv_forw_packet_bcasts_left(struct batadv_forw_packet *forw_packet)
1017 {
1018         return BATADV_SKB_CB(forw_packet->skb)->num_bcasts;
1019 }
1020
1021 /**
1022  * batadv_forw_packet_bcasts_dec() - decrement retransmission counter of a
1023  *  packet
1024  * @forw_packet: the packet to decrease the counter for
1025  */
1026 static void
1027 batadv_forw_packet_bcasts_dec(struct batadv_forw_packet *forw_packet)
1028 {
1029         BATADV_SKB_CB(forw_packet->skb)->num_bcasts--;
1030 }
1031
1032 /**
1033  * batadv_forw_packet_is_rebroadcast() - check packet for previous transmissions
1034  * @forw_packet: the packet to check
1035  *
1036  * Return: True if this packet was transmitted before, false otherwise.
1037  */
1038 bool batadv_forw_packet_is_rebroadcast(struct batadv_forw_packet *forw_packet)
1039 {
1040         unsigned char num_bcasts = BATADV_SKB_CB(forw_packet->skb)->num_bcasts;
1041
1042         return num_bcasts != forw_packet->if_outgoing->num_bcasts;
1043 }
1044
1045 /**
1046  * batadv_send_outstanding_bcast_packet() - transmit a queued broadcast packet
1047  * @work: work queue item
1048  *
1049  * Transmits a queued broadcast packet and if necessary reschedules it.
1050  */
1051 static void batadv_send_outstanding_bcast_packet(struct work_struct *work)
1052 {
1053         unsigned long send_time = jiffies + msecs_to_jiffies(5);
1054         struct batadv_forw_packet *forw_packet;
1055         struct delayed_work *delayed_work;
1056         struct batadv_priv *bat_priv;
1057         struct sk_buff *skb1;
1058         bool dropped = false;
1059
1060         delayed_work = to_delayed_work(work);
1061         forw_packet = container_of(delayed_work, struct batadv_forw_packet,
1062                                    delayed_work);
1063         bat_priv = netdev_priv(forw_packet->if_incoming->soft_iface);
1064
1065         if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING) {
1066                 dropped = true;
1067                 goto out;
1068         }
1069
1070         if (batadv_dat_drop_broadcast_packet(bat_priv, forw_packet)) {
1071                 dropped = true;
1072                 goto out;
1073         }
1074
1075         /* send a copy of the saved skb */
1076         skb1 = skb_clone(forw_packet->skb, GFP_ATOMIC);
1077         if (!skb1)
1078                 goto out;
1079
1080         batadv_send_broadcast_skb(skb1, forw_packet->if_outgoing);
1081         batadv_forw_packet_bcasts_dec(forw_packet);
1082
1083         if (batadv_forw_packet_bcasts_left(forw_packet)) {
1084                 batadv_forw_packet_bcast_queue(bat_priv, forw_packet,
1085                                                send_time);
1086                 return;
1087         }
1088
1089 out:
1090         /* do we get something for free()? */
1091         if (batadv_forw_packet_steal(forw_packet,
1092                                      &bat_priv->forw_bcast_list_lock))
1093                 batadv_forw_packet_free(forw_packet, dropped);
1094 }
1095
1096 /**
1097  * batadv_purge_outstanding_packets() - stop/purge scheduled bcast/OGMv1 packets
1098  * @bat_priv: the bat priv with all the soft interface information
1099  * @hard_iface: the hard interface to cancel and purge bcast/ogm packets on
1100  *
1101  * This method cancels and purges any broadcast and OGMv1 packet on the given
1102  * hard_iface. If hard_iface is NULL, broadcast and OGMv1 packets on all hard
1103  * interfaces will be canceled and purged.
1104  *
1105  * This function might sleep.
1106  */
1107 void
1108 batadv_purge_outstanding_packets(struct batadv_priv *bat_priv,
1109                                  const struct batadv_hard_iface *hard_iface)
1110 {
1111         struct hlist_head head = HLIST_HEAD_INIT;
1112
1113         if (hard_iface)
1114                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
1115                            "%s(): %s\n",
1116                            __func__, hard_iface->net_dev->name);
1117         else
1118                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
1119                            "%s()\n", __func__);
1120
1121         /* claim bcast list for free() */
1122         spin_lock_bh(&bat_priv->forw_bcast_list_lock);
1123         batadv_forw_packet_list_steal(&bat_priv->forw_bcast_list, &head,
1124                                       hard_iface);
1125         spin_unlock_bh(&bat_priv->forw_bcast_list_lock);
1126
1127         /* claim batman packet list for free() */
1128         spin_lock_bh(&bat_priv->forw_bat_list_lock);
1129         batadv_forw_packet_list_steal(&bat_priv->forw_bat_list, &head,
1130                                       hard_iface);
1131         spin_unlock_bh(&bat_priv->forw_bat_list_lock);
1132
1133         /* then cancel or wait for packet workers to finish and free */
1134         batadv_forw_packet_list_free(&head);
1135 }