net/batman-adv/send.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright (C) 2007-2018  B.A.T.M.A.N. contributors:
   3  *
   4  * Marek Lindner, Simon Wunderlich
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of version 2 of the GNU General Public
   8  * License as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  13  * General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 #include "send.h"
  20 #include "main.h"
  21
  22 #include <linux/atomic.h>
  23 #include <linux/bug.h>
  24 #include <linux/byteorder/generic.h>
  25 #include <linux/errno.h>
  26 #include <linux/etherdevice.h>
  27 #include <linux/gfp.h>
  28 #include <linux/if.h>
  29 #include <linux/if_ether.h>
  30 #include <linux/jiffies.h>
  31 #include <linux/kernel.h>
  32 #include <linux/kref.h>
  33 #include <linux/list.h>
  34 #include <linux/netdevice.h>
  35 #include <linux/printk.h>
  36 #include <linux/rculist.h>
  37 #include <linux/rcupdate.h>
  38 #include <linux/skbuff.h>
  39 #include <linux/slab.h>
  40 #include <linux/spinlock.h>
  41 #include <linux/stddef.h>
  42 #include <linux/workqueue.h>
  43
  44 #include "distributed-arp-table.h"
  45 #include "fragmentation.h"
  46 #include "gateway_client.h"
  47 #include "hard-interface.h"
  48 #include "log.h"
  49 #include "network-coding.h"
  50 #include "originator.h"
  51 #include "routing.h"
  52 #include "soft-interface.h"
  53 #include "translation-table.h"
  54
  55 static void batadv_send_outstanding_bcast_packet(struct work_struct *work);
  56
  57 /**
  58  * batadv_send_skb_packet() - send an already prepared packet
  59  * @skb: the packet to send
  60  * @hard_iface: the interface to use to send the broadcast packet
  61  * @dst_addr: the payload destination
  62  *
  63  * Send out an already prepared packet to the given neighbor or broadcast it
  64  * using the specified interface. Either hard_iface or neigh_node must be not
  65  * NULL.
  66  * If neigh_node is NULL, then the packet is broadcasted using hard_iface,
  67  * otherwise it is sent as unicast to the given neighbor.
  68  *
  69  * Regardless of the return value, the skb is consumed.
  70  *
  71  * Return: A negative errno code is returned on a failure. A success does not
  72  * guarantee the frame will be transmitted as it may be dropped due
  73  * to congestion or traffic shaping.
  74  */
  75 int batadv_send_skb_packet(struct sk_buff *skb,
  76                            struct batadv_hard_iface *hard_iface,
  77                            const u8 *dst_addr)
  78 {
  79         struct batadv_priv *bat_priv;
  80         struct ethhdr *ethhdr;
  81         int ret;
  82
  83         bat_priv = netdev_priv(hard_iface->soft_iface);
  84
  85         if (hard_iface->if_status != BATADV_IF_ACTIVE)
  86                 goto send_skb_err;
  87
  88         if (unlikely(!hard_iface->net_dev))
  89                 goto send_skb_err;
  90
  91         if (!(hard_iface->net_dev->flags & IFF_UP)) {
  92                 pr_warn("Interface %s is not up - can't send packet via that interface!\n",
  93                         hard_iface->net_dev->name);
  94                 goto send_skb_err;
  95         }
  96
  97         /* push to the ethernet header. */
  98         if (batadv_skb_head_push(skb, ETH_HLEN) < 0)
  99                 goto send_skb_err;
 100
 101         skb_reset_mac_header(skb);
 102
 103         ethhdr = eth_hdr(skb);
 104         ether_addr_copy(ethhdr->h_source, hard_iface->net_dev->dev_addr);
 105         ether_addr_copy(ethhdr->h_dest, dst_addr);
 106         ethhdr->h_proto = htons(ETH_P_BATMAN);
 107
 108         skb_set_network_header(skb, ETH_HLEN);
 109         skb->protocol = htons(ETH_P_BATMAN);
 110
 111         skb->dev = hard_iface->net_dev;
 112
 113         /* Save a clone of the skb to use when decoding coded packets */
 114         batadv_nc_skb_store_for_decoding(bat_priv, skb);
 115
 116         /* dev_queue_xmit() returns a negative result on error.  However on
 117          * congestion and traffic shaping, it drops and returns NET_XMIT_DROP
 118          * (which is > 0). This will not be treated as an error.
 119          */
 120         ret = dev_queue_xmit(skb);
 121         return net_xmit_eval(ret);
 122 send_skb_err:
 123         kfree_skb(skb);
 124         return NET_XMIT_DROP;
 125 }
 126
 127 /**
 128  * batadv_send_broadcast_skb() - Send broadcast packet via hard interface
 129  * @skb: packet to be transmitted (with batadv header and no outer eth header)
 130  * @hard_iface: outgoing interface
 131  *
 132  * Return: A negative errno code is returned on a failure. A success does not
 133  * guarantee the frame will be transmitted as it may be dropped due
 134  * to congestion or traffic shaping.
 135  */
 136 int batadv_send_broadcast_skb(struct sk_buff *skb,
 137                               struct batadv_hard_iface *hard_iface)
 138 {
 139         return batadv_send_skb_packet(skb, hard_iface, batadv_broadcast_addr);
 140 }
 141
 142 /**
 143  * batadv_send_unicast_skb() - Send unicast packet to neighbor
 144  * @skb: packet to be transmitted (with batadv header and no outer eth header)
 145  * @neigh: neighbor which is used as next hop to destination
 146  *
 147  * Return: A negative errno code is returned on a failure. A success does not
 148  * guarantee the frame will be transmitted as it may be dropped due
 149  * to congestion or traffic shaping.
 150  */
 151 int batadv_send_unicast_skb(struct sk_buff *skb,
 152                             struct batadv_neigh_node *neigh)
 153 {
 154 #ifdef CONFIG_BATMAN_ADV_BATMAN_V
 155         struct batadv_hardif_neigh_node *hardif_neigh;
 156 #endif
 157         int ret;
 158
 159         ret = batadv_send_skb_packet(skb, neigh->if_incoming, neigh->addr);
 160
 161 #ifdef CONFIG_BATMAN_ADV_BATMAN_V
 162         hardif_neigh = batadv_hardif_neigh_get(neigh->if_incoming, neigh->addr);
 163
 164         if (hardif_neigh && ret != NET_XMIT_DROP)
 165                 hardif_neigh->bat_v.last_unicast_tx = jiffies;
 166
 167         if (hardif_neigh)
 168                 batadv_hardif_neigh_put(hardif_neigh);
 169 #endif
 170
 171         return ret;
 172 }
 173
 174 /**
 175  * batadv_send_skb_to_orig() - Lookup next-hop and transmit skb.
 176  * @skb: Packet to be transmitted.
 177  * @orig_node: Final destination of the packet.
 178  * @recv_if: Interface used when receiving the packet (can be NULL).
 179  *
 180  * Looks up the best next-hop towards the passed originator and passes the
 181  * skb on for preparation of MAC header. If the packet originated from this
 182  * host, NULL can be passed as recv_if and no interface alternating is
 183  * attempted.
 184  *
 185  * Return: negative errno code on a failure, -EINPROGRESS if the skb is
 186  * buffered for later transmit or the NET_XMIT status returned by the
 187  * lower routine if the packet has been passed down.
 188  */
 189 int batadv_send_skb_to_orig(struct sk_buff *skb,
 190                             struct batadv_orig_node *orig_node,
 191                             struct batadv_hard_iface *recv_if)
 192 {
 193         struct batadv_priv *bat_priv = orig_node->bat_priv;
 194         struct batadv_neigh_node *neigh_node;
 195         int ret;
 196
 197         /* batadv_find_router() increases neigh_nodes refcount if found. */
 198         neigh_node = batadv_find_router(bat_priv, orig_node, recv_if);
 199         if (!neigh_node) {
 200                 ret = -EINVAL;
 201                 goto free_skb;
 202         }
 203
 204         /* Check if the skb is too large to send in one piece and fragment
 205          * it if needed.
 206          */
 207         if (atomic_read(&bat_priv->fragmentation) &&
 208             skb->len > neigh_node->if_incoming->net_dev->mtu) {
 209                 /* Fragment and send packet. */
 210                 ret = batadv_frag_send_packet(skb, orig_node, neigh_node);
 211                 /* skb was consumed */
 212                 skb = NULL;
 213
 214                 goto put_neigh_node;
 215         }
 216
 217         /* try to network code the packet, if it is received on an interface
 218          * (i.e. being forwarded). If the packet originates from this node or if
 219          * network coding fails, then send the packet as usual.
 220          */
 221         if (recv_if && batadv_nc_skb_forward(skb, neigh_node))
 222                 ret = -EINPROGRESS;
 223         else
 224                 ret = batadv_send_unicast_skb(skb, neigh_node);
 225
 226         /* skb was consumed */
 227         skb = NULL;
 228
 229 put_neigh_node:
 230         batadv_neigh_node_put(neigh_node);
 231 free_skb:
 232         kfree_skb(skb);
 233
 234         return ret;
 235 }
 236
 237 /**
 238  * batadv_send_skb_push_fill_unicast() - extend the buffer and initialize the
 239  *  common fields for unicast packets
 240  * @skb: the skb carrying the unicast header to initialize
 241  * @hdr_size: amount of bytes to push at the beginning of the skb
 242  * @orig_node: the destination node
 243  *
 244  * Return: false if the buffer extension was not possible or true otherwise.
 245  */
 246 static bool
 247 batadv_send_skb_push_fill_unicast(struct sk_buff *skb, int hdr_size,
 248                                   struct batadv_orig_node *orig_node)
 249 {
 250         struct batadv_unicast_packet *unicast_packet;
 251         u8 ttvn = (u8)atomic_read(&orig_node->last_ttvn);
 252
 253         if (batadv_skb_head_push(skb, hdr_size) < 0)
 254                 return false;
 255
 256         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 257         unicast_packet->version = BATADV_COMPAT_VERSION;
 258         /* batman packet type: unicast */
 259         unicast_packet->packet_type = BATADV_UNICAST;
 260         /* set unicast ttl */
 261         unicast_packet->ttl = BATADV_TTL;
 262         /* copy the destination for faster routing */
 263         ether_addr_copy(unicast_packet->dest, orig_node->orig);
 264         /* set the destination tt version number */
 265         unicast_packet->ttvn = ttvn;
 266
 267         return true;
 268 }
 269
 270 /**
 271  * batadv_send_skb_prepare_unicast() - encapsulate an skb with a unicast header
 272  * @skb: the skb containing the payload to encapsulate
 273  * @orig_node: the destination node
 274  *
 275  * Return: false if the payload could not be encapsulated or true otherwise.
 276  */
 277 static bool batadv_send_skb_prepare_unicast(struct sk_buff *skb,
 278                                             struct batadv_orig_node *orig_node)
 279 {
 280         size_t uni_size = sizeof(struct batadv_unicast_packet);
 281
 282         return batadv_send_skb_push_fill_unicast(skb, uni_size, orig_node);
 283 }
 284
 285 /**
 286  * batadv_send_skb_prepare_unicast_4addr() - encapsulate an skb with a
 287  *  unicast 4addr header
 288  * @bat_priv: the bat priv with all the soft interface information
 289  * @skb: the skb containing the payload to encapsulate
 290  * @orig: the destination node
 291  * @packet_subtype: the unicast 4addr packet subtype to use
 292  *
 293  * Return: false if the payload could not be encapsulated or true otherwise.
 294  */
 295 bool batadv_send_skb_prepare_unicast_4addr(struct batadv_priv *bat_priv,
 296                                            struct sk_buff *skb,
 297                                            struct batadv_orig_node *orig,
 298                                            int packet_subtype)
 299 {
 300         struct batadv_hard_iface *primary_if;
 301         struct batadv_unicast_4addr_packet *uc_4addr_packet;
 302         bool ret = false;
 303
 304         primary_if = batadv_primary_if_get_selected(bat_priv);
 305         if (!primary_if)
 306                 goto out;
 307
 308         /* Pull the header space and fill the unicast_packet substructure.
 309          * We can do that because the first member of the uc_4addr_packet
 310          * is of type struct unicast_packet
 311          */
 312         if (!batadv_send_skb_push_fill_unicast(skb, sizeof(*uc_4addr_packet),
 313                                                orig))
 314                 goto out;
 315
 316         uc_4addr_packet = (struct batadv_unicast_4addr_packet *)skb->data;
 317         uc_4addr_packet->u.packet_type = BATADV_UNICAST_4ADDR;
 318         ether_addr_copy(uc_4addr_packet->src, primary_if->net_dev->dev_addr);
 319         uc_4addr_packet->subtype = packet_subtype;
 320         uc_4addr_packet->reserved = 0;
 321
 322         ret = true;
 323 out:
 324         if (primary_if)
 325                 batadv_hardif_put(primary_if);
 326         return ret;
 327 }
 328
 329 /**
 330  * batadv_send_skb_unicast() - encapsulate and send an skb via unicast
 331  * @bat_priv: the bat priv with all the soft interface information
 332  * @skb: payload to send
 333  * @packet_type: the batman unicast packet type to use
 334  * @packet_subtype: the unicast 4addr packet subtype (only relevant for unicast
 335  *  4addr packets)
 336  * @orig_node: the originator to send the packet to
 337  * @vid: the vid to be used to search the translation table
 338  *
 339  * Wrap the given skb into a batman-adv unicast or unicast-4addr header
 340  * depending on whether BATADV_UNICAST or BATADV_UNICAST_4ADDR was supplied
 341  * as packet_type. Then send this frame to the given orig_node.
 342  *
 343  * Return: NET_XMIT_DROP in case of error or NET_XMIT_SUCCESS otherwise.
 344  */
 345 int batadv_send_skb_unicast(struct batadv_priv *bat_priv,
 346                             struct sk_buff *skb, int packet_type,
 347                             int packet_subtype,
 348                             struct batadv_orig_node *orig_node,
 349                             unsigned short vid)
 350 {
 351         struct batadv_unicast_packet *unicast_packet;
 352         struct ethhdr *ethhdr;
 353         int ret = NET_XMIT_DROP;
 354
 355         if (!orig_node)
 356                 goto out;
 357
 358         switch (packet_type) {
 359         case BATADV_UNICAST:
 360                 if (!batadv_send_skb_prepare_unicast(skb, orig_node))
 361                         goto out;
 362                 break;
 363         case BATADV_UNICAST_4ADDR:
 364                 if (!batadv_send_skb_prepare_unicast_4addr(bat_priv, skb,
 365                                                            orig_node,
 366                                                            packet_subtype))
 367                         goto out;
 368                 break;
 369         default:
 370                 /* this function supports UNICAST and UNICAST_4ADDR only. It
 371                  * should never be invoked with any other packet type
 372                  */
 373                 goto out;
 374         }
 375
 376         /* skb->data might have been reallocated by
 377          * batadv_send_skb_prepare_unicast{,_4addr}()
 378          */
 379         ethhdr = eth_hdr(skb);
 380         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 381
 382         /* inform the destination node that we are still missing a correct route
 383          * for this client. The destination will receive this packet and will
 384          * try to reroute it because the ttvn contained in the header is less
 385          * than the current one
 386          */
 387         if (batadv_tt_global_client_is_roaming(bat_priv, ethhdr->h_dest, vid))
 388                 unicast_packet->ttvn = unicast_packet->ttvn - 1;
 389
 390         ret = batadv_send_skb_to_orig(skb, orig_node, NULL);
 391          /* skb was consumed */
 392         skb = NULL;
 393
 394 out:
 395         kfree_skb(skb);
 396         return ret;
 397 }
 398
 399 /**
 400  * batadv_send_skb_via_tt_generic() - send an skb via TT lookup
 401  * @bat_priv: the bat priv with all the soft interface information
 402  * @skb: payload to send
 403  * @packet_type: the batman unicast packet type to use
 404  * @packet_subtype: the unicast 4addr packet subtype (only relevant for unicast
 405  *  4addr packets)
 406  * @dst_hint: can be used to override the destination contained in the skb
 407  * @vid: the vid to be used to search the translation table
 408  *
 409  * Look up the recipient node for the destination address in the ethernet
 410  * header via the translation table. Wrap the given skb into a batman-adv
 411  * unicast or unicast-4addr header depending on whether BATADV_UNICAST or
 412  * BATADV_UNICAST_4ADDR was supplied as packet_type. Then send this frame
 413  * to the according destination node.
 414  *
 415  * Return: NET_XMIT_DROP in case of error or NET_XMIT_SUCCESS otherwise.
 416  */
 417 int batadv_send_skb_via_tt_generic(struct batadv_priv *bat_priv,
 418                                    struct sk_buff *skb, int packet_type,
 419                                    int packet_subtype, u8 *dst_hint,
 420                                    unsigned short vid)
 421 {
 422         struct ethhdr *ethhdr = (struct ethhdr *)skb->data;
 423         struct batadv_orig_node *orig_node;
 424         u8 *src, *dst;
 425         int ret;
 426
 427         src = ethhdr->h_source;
 428         dst = ethhdr->h_dest;
 429
 430         /* if we got an hint! let's send the packet to this client (if any) */
 431         if (dst_hint) {
 432                 src = NULL;
 433                 dst = dst_hint;
 434         }
 435         orig_node = batadv_transtable_search(bat_priv, src, dst, vid);
 436
 437         ret = batadv_send_skb_unicast(bat_priv, skb, packet_type,
 438                                       packet_subtype, orig_node, vid);
 439
 440         if (orig_node)
 441                 batadv_orig_node_put(orig_node);
 442
 443         return ret;
 444 }
 445
 446 /**
 447  * batadv_send_skb_via_gw() - send an skb via gateway lookup
 448  * @bat_priv: the bat priv with all the soft interface information
 449  * @skb: payload to send
 450  * @vid: the vid to be used to search the translation table
 451  *
 452  * Look up the currently selected gateway. Wrap the given skb into a batman-adv
 453  * unicast header and send this frame to this gateway node.
 454  *
 455  * Return: NET_XMIT_DROP in case of error or NET_XMIT_SUCCESS otherwise.
 456  */
 457 int batadv_send_skb_via_gw(struct batadv_priv *bat_priv, struct sk_buff *skb,
 458                            unsigned short vid)
 459 {
 460         struct batadv_orig_node *orig_node;
 461         int ret;
 462
 463         orig_node = batadv_gw_get_selected_orig(bat_priv);
 464         ret = batadv_send_skb_unicast(bat_priv, skb, BATADV_UNICAST_4ADDR,
 465                                       BATADV_P_DATA, orig_node, vid);
 466
 467         if (orig_node)
 468                 batadv_orig_node_put(orig_node);
 469
 470         return ret;
 471 }
 472
 473 /**
 474  * batadv_forw_packet_free() - free a forwarding packet
 475  * @forw_packet: The packet to free
 476  * @dropped: whether the packet is freed because is is dropped
 477  *
 478  * This frees a forwarding packet and releases any resources it might
 479  * have claimed.
 480  */
 481 void batadv_forw_packet_free(struct batadv_forw_packet *forw_packet,
 482                              bool dropped)
 483 {
 484         if (dropped)
 485                 kfree_skb(forw_packet->skb);
 486         else
 487                 consume_skb(forw_packet->skb);
 488
 489         if (forw_packet->if_incoming)
 490                 batadv_hardif_put(forw_packet->if_incoming);
 491         if (forw_packet->if_outgoing)
 492                 batadv_hardif_put(forw_packet->if_outgoing);
 493         if (forw_packet->queue_left)
 494                 atomic_inc(forw_packet->queue_left);
 495         kfree(forw_packet);
 496 }
 497
 498 /**
 499  * batadv_forw_packet_alloc() - allocate a forwarding packet
 500  * @if_incoming: The (optional) if_incoming to be grabbed
 501  * @if_outgoing: The (optional) if_outgoing to be grabbed
 502  * @queue_left: The (optional) queue counter to decrease
 503  * @bat_priv: The bat_priv for the mesh of this forw_packet
 504  * @skb: The raw packet this forwarding packet shall contain
 505  *
 506  * Allocates a forwarding packet and tries to get a reference to the
 507  * (optional) if_incoming, if_outgoing and queue_left. If queue_left
 508  * is NULL then bat_priv is optional, too.
 509  *
 510  * Return: An allocated forwarding packet on success, NULL otherwise.
 511  */
 512 struct batadv_forw_packet *
 513 batadv_forw_packet_alloc(struct batadv_hard_iface *if_incoming,
 514                          struct batadv_hard_iface *if_outgoing,
 515                          atomic_t *queue_left,
 516                          struct batadv_priv *bat_priv,
 517                          struct sk_buff *skb)
 518 {
 519         struct batadv_forw_packet *forw_packet;
 520         const char *qname;
 521
 522         if (queue_left && !batadv_atomic_dec_not_zero(queue_left)) {
 523                 qname = "unknown";
 524
 525                 if (queue_left == &bat_priv->bcast_queue_left)
 526                         qname = "bcast";
 527
 528                 if (queue_left == &bat_priv->batman_queue_left)
 529                         qname = "batman";
 530
 531                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 532                            "%s queue is full\n", qname);
 533
 534                 return NULL;
 535         }
 536
 537         forw_packet = kmalloc(sizeof(*forw_packet), GFP_ATOMIC);
 538         if (!forw_packet)
 539                 goto err;
 540
 541         if (if_incoming)
 542                 kref_get(&if_incoming->refcount);
 543
 544         if (if_outgoing)
 545                 kref_get(&if_outgoing->refcount);
 546
 547         INIT_HLIST_NODE(&forw_packet->list);
 548         INIT_HLIST_NODE(&forw_packet->cleanup_list);
 549         forw_packet->skb = skb;
 550         forw_packet->queue_left = queue_left;
 551         forw_packet->if_incoming = if_incoming;
 552         forw_packet->if_outgoing = if_outgoing;
 553         forw_packet->num_packets = 0;
 554
 555         return forw_packet;
 556
 557 err:
 558         if (queue_left)
 559                 atomic_inc(queue_left);
 560
 561         return NULL;
 562 }
 563
 564 /**
 565  * batadv_forw_packet_was_stolen() - check whether someone stole this packet
 566  * @forw_packet: the forwarding packet to check
 567  *
 568  * This function checks whether the given forwarding packet was claimed by
 569  * someone else for free().
 570  *
 571  * Return: True if someone stole it, false otherwise.
 572  */
 573 static bool
 574 batadv_forw_packet_was_stolen(struct batadv_forw_packet *forw_packet)
 575 {
 576         return !hlist_unhashed(&forw_packet->cleanup_list);
 577 }
 578
 579 /**
 580  * batadv_forw_packet_steal() - claim a forw_packet for free()
 581  * @forw_packet: the forwarding packet to steal
 582  * @lock: a key to the store to steal from (e.g. forw_{bat,bcast}_list_lock)
 583  *
 584  * This function tries to steal a specific forw_packet from global
 585  * visibility for the purpose of getting it for free(). That means
 586  * the caller is *not* allowed to requeue it afterwards.
 587  *
 588  * Return: True if stealing was successful. False if someone else stole it
 589  * before us.
 590  */
 591 bool batadv_forw_packet_steal(struct batadv_forw_packet *forw_packet,
 592                               spinlock_t *lock)
 593 {
 594         /* did purging routine steal it earlier? */
 595         spin_lock_bh(lock);
 596         if (batadv_forw_packet_was_stolen(forw_packet)) {
 597                 spin_unlock_bh(lock);
 598                 return false;
 599         }
 600
 601         hlist_del_init(&forw_packet->list);
 602
 603         /* Just to spot misuse of this function */
 604         hlist_add_fake(&forw_packet->cleanup_list);
 605
 606         spin_unlock_bh(lock);
 607         return true;
 608 }
 609
 610 /**
 611  * batadv_forw_packet_list_steal() - claim a list of forward packets for free()
 612  * @forw_list: the to be stolen forward packets
 613  * @cleanup_list: a backup pointer, to be able to dispose the packet later
 614  * @hard_iface: the interface to steal forward packets from
 615  *
 616  * This function claims responsibility to free any forw_packet queued on the
 617  * given hard_iface. If hard_iface is NULL forwarding packets on all hard
 618  * interfaces will be claimed.
 619  *
 620  * The packets are being moved from the forw_list to the cleanup_list and
 621  * by that allows already running threads to notice the claiming.
 622  */
 623 static void
 624 batadv_forw_packet_list_steal(struct hlist_head *forw_list,
 625                               struct hlist_head *cleanup_list,
 626                               const struct batadv_hard_iface *hard_iface)
 627 {
 628         struct batadv_forw_packet *forw_packet;
 629         struct hlist_node *safe_tmp_node;
 630
 631         hlist_for_each_entry_safe(forw_packet, safe_tmp_node,
 632                                   forw_list, list) {
 633                 /* if purge_outstanding_packets() was called with an argument
 634                  * we delete only packets belonging to the given interface
 635                  */
 636                 if (hard_iface &&
 637                     forw_packet->if_incoming != hard_iface &&
 638                     forw_packet->if_outgoing != hard_iface)
 639                         continue;
 640
 641                 hlist_del(&forw_packet->list);
 642                 hlist_add_head(&forw_packet->cleanup_list, cleanup_list);
 643         }
 644 }
 645
 646 /**
 647  * batadv_forw_packet_list_free() - free a list of forward packets
 648  * @head: a list of to be freed forw_packets
 649  *
 650  * This function cancels the scheduling of any packet in the provided list,
 651  * waits for any possibly running packet forwarding thread to finish and
 652  * finally, safely frees this forward packet.
 653  *
 654  * This function might sleep.
 655  */
 656 static void batadv_forw_packet_list_free(struct hlist_head *head)
 657 {
 658         struct batadv_forw_packet *forw_packet;
 659         struct hlist_node *safe_tmp_node;
 660
 661         hlist_for_each_entry_safe(forw_packet, safe_tmp_node, head,
 662                                   cleanup_list) {
 663                 cancel_delayed_work_sync(&forw_packet->delayed_work);
 664
 665                 hlist_del(&forw_packet->cleanup_list);
 666                 batadv_forw_packet_free(forw_packet, true);
 667         }
 668 }
 669
 670 /**
 671  * batadv_forw_packet_queue() - try to queue a forwarding packet
 672  * @forw_packet: the forwarding packet to queue
 673  * @lock: a key to the store (e.g. forw_{bat,bcast}_list_lock)
 674  * @head: the shelve to queue it on (e.g. forw_{bat,bcast}_list)
 675  * @send_time: timestamp (jiffies) when the packet is to be sent
 676  *
 677  * This function tries to (re)queue a forwarding packet. Requeuing
 678  * is prevented if the according interface is shutting down
 679  * (e.g. if batadv_forw_packet_list_steal() was called for this
 680  * packet earlier).
 681  *
 682  * Calling batadv_forw_packet_queue() after a call to
 683  * batadv_forw_packet_steal() is forbidden!
 684  *
 685  * Caller needs to ensure that forw_packet->delayed_work was initialized.
 686  */
 687 static void batadv_forw_packet_queue(struct batadv_forw_packet *forw_packet,
 688                                      spinlock_t *lock, struct hlist_head *head,
 689                                      unsigned long send_time)
 690 {
 691         spin_lock_bh(lock);
 692
 693         /* did purging routine steal it from us? */
 694         if (batadv_forw_packet_was_stolen(forw_packet)) {
 695                 /* If you got it for free() without trouble, then
 696                  * don't get back into the queue after stealing...
 697                  */
 698                 WARN_ONCE(hlist_fake(&forw_packet->cleanup_list),
 699                           "Requeuing after batadv_forw_packet_steal() not allowed!\n");
 700
 701                 spin_unlock_bh(lock);
 702                 return;
 703         }
 704
 705         hlist_del_init(&forw_packet->list);
 706         hlist_add_head(&forw_packet->list, head);
 707
 708         queue_delayed_work(batadv_event_workqueue,
 709                            &forw_packet->delayed_work,
 710                            send_time - jiffies);
 711         spin_unlock_bh(lock);
 712 }
 713
 714 /**
 715  * batadv_forw_packet_bcast_queue() - try to queue a broadcast packet
 716  * @bat_priv: the bat priv with all the soft interface information
 717  * @forw_packet: the forwarding packet to queue
 718  * @send_time: timestamp (jiffies) when the packet is to be sent
 719  *
 720  * This function tries to (re)queue a broadcast packet.
 721  *
 722  * Caller needs to ensure that forw_packet->delayed_work was initialized.
 723  */
 724 static void
 725 batadv_forw_packet_bcast_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_bcast_list_lock,
 730                                  &bat_priv->forw_bcast_list, send_time);
 731 }
 732
 733 /**
 734  * batadv_forw_packet_ogmv1_queue() - try to queue an OGMv1 packet
 735  * @bat_priv: the bat priv with all the soft interface information
 736  * @forw_packet: the forwarding packet to queue
 737  * @send_time: timestamp (jiffies) when the packet is to be sent
 738  *
 739  * This function tries to (re)queue an OGMv1 packet.
 740  *
 741  * Caller needs to ensure that forw_packet->delayed_work was initialized.
 742  */
 743 void batadv_forw_packet_ogmv1_queue(struct batadv_priv *bat_priv,
 744                                     struct batadv_forw_packet *forw_packet,
 745                                     unsigned long send_time)
 746 {
 747         batadv_forw_packet_queue(forw_packet, &bat_priv->forw_bat_list_lock,
 748                                  &bat_priv->forw_bat_list, send_time);
 749 }
 750
 751 /**
 752  * batadv_add_bcast_packet_to_list() - queue broadcast packet for multiple sends
 753  * @bat_priv: the bat priv with all the soft interface information
 754  * @skb: broadcast packet to add
 755  * @delay: number of jiffies to wait before sending
 756  * @own_packet: true if it is a self-generated broadcast packet
 757  *
 758  * add a broadcast packet to the queue and setup timers. broadcast packets
 759  * are sent multiple times to increase probability for being received.
 760  *
 761  * The skb is not consumed, so the caller should make sure that the
 762  * skb is freed.
 763  *
 764  * Return: NETDEV_TX_OK on success and NETDEV_TX_BUSY on errors.
 765  */
 766 int batadv_add_bcast_packet_to_list(struct batadv_priv *bat_priv,
 767                                     const struct sk_buff *skb,
 768                                     unsigned long delay,
 769                                     bool own_packet)
 770 {
 771         struct batadv_hard_iface *primary_if;
 772         struct batadv_forw_packet *forw_packet;
 773         struct batadv_bcast_packet *bcast_packet;
 774         struct sk_buff *newskb;
 775
 776         primary_if = batadv_primary_if_get_selected(bat_priv);
 777         if (!primary_if)
 778                 goto err;
 779
 780         newskb = skb_copy(skb, GFP_ATOMIC);
 781         if (!newskb) {
 782                 batadv_hardif_put(primary_if);
 783                 goto err;
 784         }
 785
 786         forw_packet = batadv_forw_packet_alloc(primary_if, NULL,
 787                                                &bat_priv->bcast_queue_left,
 788                                                bat_priv, newskb);
 789         batadv_hardif_put(primary_if);
 790         if (!forw_packet)
 791                 goto err_packet_free;
 792
 793         /* as we have a copy now, it is safe to decrease the TTL */
 794         bcast_packet = (struct batadv_bcast_packet *)newskb->data;
 795         bcast_packet->ttl--;
 796
 797         forw_packet->own = own_packet;
 798
 799         INIT_DELAYED_WORK(&forw_packet->delayed_work,
 800                           batadv_send_outstanding_bcast_packet);
 801
 802         batadv_forw_packet_bcast_queue(bat_priv, forw_packet, jiffies + delay);
 803         return NETDEV_TX_OK;
 804
 805 err_packet_free:
 806         kfree_skb(newskb);
 807 err:
 808         return NETDEV_TX_BUSY;
 809 }
 810
 811 /**
 812  * batadv_forw_packet_bcasts_left() - check if a retransmission is necessary
 813  * @forw_packet: the forwarding packet to check
 814  * @hard_iface: the interface to check on
 815  *
 816  * Checks whether a given packet has any (re)transmissions left on the provided
 817  * interface.
 818  *
 819  * hard_iface may be NULL: In that case the number of transmissions this skb had
 820  * so far is compared with the maximum amount of retransmissions independent of
 821  * any interface instead.
 822  *
 823  * Return: True if (re)transmissions are left, false otherwise.
 824  */
 825 static bool
 826 batadv_forw_packet_bcasts_left(struct batadv_forw_packet *forw_packet,
 827                                struct batadv_hard_iface *hard_iface)
 828 {
 829         unsigned int max;
 830
 831         if (hard_iface)
 832                 max = hard_iface->num_bcasts;
 833         else
 834                 max = BATADV_NUM_BCASTS_MAX;
 835
 836         return BATADV_SKB_CB(forw_packet->skb)->num_bcasts < max;
 837 }
 838
 839 /**
 840  * batadv_forw_packet_bcasts_inc() - increment retransmission counter of a
 841  *  packet
 842  * @forw_packet: the packet to increase the counter for
 843  */
 844 static void
 845 batadv_forw_packet_bcasts_inc(struct batadv_forw_packet *forw_packet)
 846 {
 847         BATADV_SKB_CB(forw_packet->skb)->num_bcasts++;
 848 }
 849
 850 /**
 851  * batadv_forw_packet_is_rebroadcast() - check packet for previous transmissions
 852  * @forw_packet: the packet to check
 853  *
 854  * Return: True if this packet was transmitted before, false otherwise.
 855  */
 856 bool batadv_forw_packet_is_rebroadcast(struct batadv_forw_packet *forw_packet)
 857 {
 858         return BATADV_SKB_CB(forw_packet->skb)->num_bcasts > 0;
 859 }
 860
 861 static void batadv_send_outstanding_bcast_packet(struct work_struct *work)
 862 {
 863         struct batadv_hard_iface *hard_iface;
 864         struct batadv_hardif_neigh_node *neigh_node;
 865         struct delayed_work *delayed_work;
 866         struct batadv_forw_packet *forw_packet;
 867         struct batadv_bcast_packet *bcast_packet;
 868         struct sk_buff *skb1;
 869         struct net_device *soft_iface;
 870         struct batadv_priv *bat_priv;
 871         unsigned long send_time = jiffies + msecs_to_jiffies(5);
 872         bool dropped = false;
 873         u8 *neigh_addr;
 874         u8 *orig_neigh;
 875         int ret = 0;
 876
 877         delayed_work = to_delayed_work(work);
 878         forw_packet = container_of(delayed_work, struct batadv_forw_packet,
 879                                    delayed_work);
 880         soft_iface = forw_packet->if_incoming->soft_iface;
 881         bat_priv = netdev_priv(soft_iface);
 882
 883         if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING) {
 884                 dropped = true;
 885                 goto out;
 886         }
 887
 888         if (batadv_dat_drop_broadcast_packet(bat_priv, forw_packet)) {
 889                 dropped = true;
 890                 goto out;
 891         }
 892
 893         bcast_packet = (struct batadv_bcast_packet *)forw_packet->skb->data;
 894
 895         /* rebroadcast packet */
 896         rcu_read_lock();
 897         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 898                 if (hard_iface->soft_iface != soft_iface)
 899                         continue;
 900
 901                 if (!batadv_forw_packet_bcasts_left(forw_packet, hard_iface))
 902                         continue;
 903
 904                 if (forw_packet->own) {
 905                         neigh_node = NULL;
 906                 } else {
 907                         neigh_addr = eth_hdr(forw_packet->skb)->h_source;
 908                         neigh_node = batadv_hardif_neigh_get(hard_iface,
 909                                                              neigh_addr);
 910                 }
 911
 912                 orig_neigh = neigh_node ? neigh_node->orig : NULL;
 913
 914                 ret = batadv_hardif_no_broadcast(hard_iface, bcast_packet->orig,
 915                                                  orig_neigh);
 916
 917                 if (ret) {
 918                         char *type;
 919
 920                         switch (ret) {
 921                         case BATADV_HARDIF_BCAST_NORECIPIENT:
 922                                 type = "no neighbor";
 923                                 break;
 924                         case BATADV_HARDIF_BCAST_DUPFWD:
 925                                 type = "single neighbor is source";
 926                                 break;
 927                         case BATADV_HARDIF_BCAST_DUPORIG:
 928                                 type = "single neighbor is originator";
 929                                 break;
 930                         default:
 931                                 type = "unknown";
 932                         }
 933
 934                         batadv_dbg(BATADV_DBG_BATMAN, bat_priv, "BCAST packet from orig %pM on %s suppressed: %s\n",
 935                                    bcast_packet->orig,
 936                                    hard_iface->net_dev->name, type);
 937
 938                         if (neigh_node)
 939                                 batadv_hardif_neigh_put(neigh_node);
 940
 941                         continue;
 942                 }
 943
 944                 if (neigh_node)
 945                         batadv_hardif_neigh_put(neigh_node);
 946
 947                 if (!kref_get_unless_zero(&hard_iface->refcount))
 948                         continue;
 949
 950                 /* send a copy of the saved skb */
 951                 skb1 = skb_clone(forw_packet->skb, GFP_ATOMIC);
 952                 if (skb1)
 953                         batadv_send_broadcast_skb(skb1, hard_iface);
 954
 955                 batadv_hardif_put(hard_iface);
 956         }
 957         rcu_read_unlock();
 958
 959         batadv_forw_packet_bcasts_inc(forw_packet);
 960
 961         /* if we still have some more bcasts to send */
 962         if (batadv_forw_packet_bcasts_left(forw_packet, NULL)) {
 963                 batadv_forw_packet_bcast_queue(bat_priv, forw_packet,
 964                                                send_time);
 965                 return;
 966         }
 967
 968 out:
 969         /* do we get something for free()? */
 970         if (batadv_forw_packet_steal(forw_packet,
 971                                      &bat_priv->forw_bcast_list_lock))
 972                 batadv_forw_packet_free(forw_packet, dropped);
 973 }
 974
 975 /**
 976  * batadv_purge_outstanding_packets() - stop/purge scheduled bcast/OGMv1 packets
 977  * @bat_priv: the bat priv with all the soft interface information
 978  * @hard_iface: the hard interface to cancel and purge bcast/ogm packets on
 979  *
 980  * This method cancels and purges any broadcast and OGMv1 packet on the given
 981  * hard_iface. If hard_iface is NULL, broadcast and OGMv1 packets on all hard
 982  * interfaces will be canceled and purged.
 983  *
 984  * This function might sleep.
 985  */
 986 void
 987 batadv_purge_outstanding_packets(struct batadv_priv *bat_priv,
 988                                  const struct batadv_hard_iface *hard_iface)
 989 {
 990         struct hlist_head head = HLIST_HEAD_INIT;
 991
 992         if (hard_iface)
 993                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 994                            "%s(): %s\n",
 995                            __func__, hard_iface->net_dev->name);
 996         else
 997                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 998                            "%s()\n", __func__);
 999
1000         /* claim bcast list for free() */
1001         spin_lock_bh(&bat_priv->forw_bcast_list_lock);
1002         batadv_forw_packet_list_steal(&bat_priv->forw_bcast_list, &head,
1003                                       hard_iface);
1004         spin_unlock_bh(&bat_priv->forw_bcast_list_lock);
1005
1006         /* claim batman packet list for free() */
1007         spin_lock_bh(&bat_priv->forw_bat_list_lock);
1008         batadv_forw_packet_list_steal(&bat_priv->forw_bat_list, &head,
1009                                       hard_iface);
1010         spin_unlock_bh(&bat_priv->forw_bat_list_lock);
1011
1012         /* then cancel or wait for packet workers to finish and free */
1013         batadv_forw_packet_list_free(&head);
1014 }