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