linux/net/batman-adv/gateway_client.c
<<
>>
Prefs
   1/* Copyright (C) 2009-2012 B.A.T.M.A.N. contributors:
   2 *
   3 * Marek Lindner
   4 *
   5 * This program is free software; you can redistribute it and/or
   6 * modify it under the terms of version 2 of the GNU General Public
   7 * License as published by the Free Software Foundation.
   8 *
   9 * This program is distributed in the hope that it will be useful, but
  10 * WITHOUT ANY WARRANTY; without even the implied warranty of
  11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  12 * General Public License for more details.
  13 *
  14 * You should have received a copy of the GNU General Public License
  15 * along with this program; if not, write to the Free Software
  16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  17 * 02110-1301, USA
  18 */
  19
  20#include "main.h"
  21#include "sysfs.h"
  22#include "gateway_client.h"
  23#include "gateway_common.h"
  24#include "hard-interface.h"
  25#include "originator.h"
  26#include "translation-table.h"
  27#include "routing.h"
  28#include <linux/ip.h>
  29#include <linux/ipv6.h>
  30#include <linux/udp.h>
  31#include <linux/if_vlan.h>
  32
  33/* This is the offset of the options field in a dhcp packet starting at
  34 * the beginning of the dhcp header
  35 */
  36#define BATADV_DHCP_OPTIONS_OFFSET 240
  37#define BATADV_DHCP_REQUEST 3
  38
  39static void batadv_gw_node_free_ref(struct batadv_gw_node *gw_node)
  40{
  41        if (atomic_dec_and_test(&gw_node->refcount))
  42                kfree_rcu(gw_node, rcu);
  43}
  44
  45static struct batadv_gw_node *
  46batadv_gw_get_selected_gw_node(struct batadv_priv *bat_priv)
  47{
  48        struct batadv_gw_node *gw_node;
  49
  50        rcu_read_lock();
  51        gw_node = rcu_dereference(bat_priv->curr_gw);
  52        if (!gw_node)
  53                goto out;
  54
  55        if (!atomic_inc_not_zero(&gw_node->refcount))
  56                gw_node = NULL;
  57
  58out:
  59        rcu_read_unlock();
  60        return gw_node;
  61}
  62
  63struct batadv_orig_node *
  64batadv_gw_get_selected_orig(struct batadv_priv *bat_priv)
  65{
  66        struct batadv_gw_node *gw_node;
  67        struct batadv_orig_node *orig_node = NULL;
  68
  69        gw_node = batadv_gw_get_selected_gw_node(bat_priv);
  70        if (!gw_node)
  71                goto out;
  72
  73        rcu_read_lock();
  74        orig_node = gw_node->orig_node;
  75        if (!orig_node)
  76                goto unlock;
  77
  78        if (!atomic_inc_not_zero(&orig_node->refcount))
  79                orig_node = NULL;
  80
  81unlock:
  82        rcu_read_unlock();
  83out:
  84        if (gw_node)
  85                batadv_gw_node_free_ref(gw_node);
  86        return orig_node;
  87}
  88
  89static void batadv_gw_select(struct batadv_priv *bat_priv,
  90                             struct batadv_gw_node *new_gw_node)
  91{
  92        struct batadv_gw_node *curr_gw_node;
  93
  94        spin_lock_bh(&bat_priv->gw_list_lock);
  95
  96        if (new_gw_node && !atomic_inc_not_zero(&new_gw_node->refcount))
  97                new_gw_node = NULL;
  98
  99        curr_gw_node = rcu_dereference_protected(bat_priv->curr_gw, 1);
 100        rcu_assign_pointer(bat_priv->curr_gw, new_gw_node);
 101
 102        if (curr_gw_node)
 103                batadv_gw_node_free_ref(curr_gw_node);
 104
 105        spin_unlock_bh(&bat_priv->gw_list_lock);
 106}
 107
 108void batadv_gw_deselect(struct batadv_priv *bat_priv)
 109{
 110        atomic_set(&bat_priv->gw_reselect, 1);
 111}
 112
 113static struct batadv_gw_node *
 114batadv_gw_get_best_gw_node(struct batadv_priv *bat_priv)
 115{
 116        struct batadv_neigh_node *router;
 117        struct hlist_node *node;
 118        struct batadv_gw_node *gw_node, *curr_gw = NULL;
 119        uint32_t max_gw_factor = 0, tmp_gw_factor = 0;
 120        uint8_t max_tq = 0;
 121        int down, up;
 122        struct batadv_orig_node *orig_node;
 123
 124        rcu_read_lock();
 125        hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
 126                if (gw_node->deleted)
 127                        continue;
 128
 129                orig_node = gw_node->orig_node;
 130                router = batadv_orig_node_get_router(orig_node);
 131                if (!router)
 132                        continue;
 133
 134                if (!atomic_inc_not_zero(&gw_node->refcount))
 135                        goto next;
 136
 137                switch (atomic_read(&bat_priv->gw_sel_class)) {
 138                case 1: /* fast connection */
 139                        batadv_gw_bandwidth_to_kbit(orig_node->gw_flags,
 140                                                    &down, &up);
 141
 142                        tmp_gw_factor = (router->tq_avg * router->tq_avg *
 143                                         down * 100 * 100) /
 144                                         (BATADV_TQ_LOCAL_WINDOW_SIZE *
 145                                          BATADV_TQ_LOCAL_WINDOW_SIZE * 64);
 146
 147                        if ((tmp_gw_factor > max_gw_factor) ||
 148                            ((tmp_gw_factor == max_gw_factor) &&
 149                             (router->tq_avg > max_tq))) {
 150                                if (curr_gw)
 151                                        batadv_gw_node_free_ref(curr_gw);
 152                                curr_gw = gw_node;
 153                                atomic_inc(&curr_gw->refcount);
 154                        }
 155                        break;
 156
 157                default: /* 2:  stable connection (use best statistic)
 158                          * 3:  fast-switch (use best statistic but change as
 159                          *     soon as a better gateway appears)
 160                          * XX: late-switch (use best statistic but change as
 161                          *     soon as a better gateway appears which has
 162                          *     $routing_class more tq points)
 163                          */
 164                        if (router->tq_avg > max_tq) {
 165                                if (curr_gw)
 166                                        batadv_gw_node_free_ref(curr_gw);
 167                                curr_gw = gw_node;
 168                                atomic_inc(&curr_gw->refcount);
 169                        }
 170                        break;
 171                }
 172
 173                if (router->tq_avg > max_tq)
 174                        max_tq = router->tq_avg;
 175
 176                if (tmp_gw_factor > max_gw_factor)
 177                        max_gw_factor = tmp_gw_factor;
 178
 179                batadv_gw_node_free_ref(gw_node);
 180
 181next:
 182                batadv_neigh_node_free_ref(router);
 183        }
 184        rcu_read_unlock();
 185
 186        return curr_gw;
 187}
 188
 189void batadv_gw_election(struct batadv_priv *bat_priv)
 190{
 191        struct batadv_gw_node *curr_gw = NULL, *next_gw = NULL;
 192        struct batadv_neigh_node *router = NULL;
 193        char gw_addr[18] = { '\0' };
 194
 195        /* The batman daemon checks here if we already passed a full originator
 196         * cycle in order to make sure we don't choose the first gateway we
 197         * hear about. This check is based on the daemon's uptime which we
 198         * don't have.
 199         */
 200        if (atomic_read(&bat_priv->gw_mode) != BATADV_GW_MODE_CLIENT)
 201                goto out;
 202
 203        curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
 204
 205        if (!batadv_atomic_dec_not_zero(&bat_priv->gw_reselect) && curr_gw)
 206                goto out;
 207
 208        next_gw = batadv_gw_get_best_gw_node(bat_priv);
 209
 210        if (curr_gw == next_gw)
 211                goto out;
 212
 213        if (next_gw) {
 214                sprintf(gw_addr, "%pM", next_gw->orig_node->orig);
 215
 216                router = batadv_orig_node_get_router(next_gw->orig_node);
 217                if (!router) {
 218                        batadv_gw_deselect(bat_priv);
 219                        goto out;
 220                }
 221        }
 222
 223        if ((curr_gw) && (!next_gw)) {
 224                batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 225                           "Removing selected gateway - no gateway in range\n");
 226                batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_DEL,
 227                                    NULL);
 228        } else if ((!curr_gw) && (next_gw)) {
 229                batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 230                           "Adding route to gateway %pM (gw_flags: %i, tq: %i)\n",
 231                           next_gw->orig_node->orig,
 232                           next_gw->orig_node->gw_flags, router->tq_avg);
 233                batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_ADD,
 234                                    gw_addr);
 235        } else {
 236                batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 237                           "Changing route to gateway %pM (gw_flags: %i, tq: %i)\n",
 238                           next_gw->orig_node->orig,
 239                           next_gw->orig_node->gw_flags, router->tq_avg);
 240                batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_CHANGE,
 241                                    gw_addr);
 242        }
 243
 244        batadv_gw_select(bat_priv, next_gw);
 245
 246out:
 247        if (curr_gw)
 248                batadv_gw_node_free_ref(curr_gw);
 249        if (next_gw)
 250                batadv_gw_node_free_ref(next_gw);
 251        if (router)
 252                batadv_neigh_node_free_ref(router);
 253}
 254
 255void batadv_gw_check_election(struct batadv_priv *bat_priv,
 256                              struct batadv_orig_node *orig_node)
 257{
 258        struct batadv_orig_node *curr_gw_orig;
 259        struct batadv_neigh_node *router_gw = NULL, *router_orig = NULL;
 260        uint8_t gw_tq_avg, orig_tq_avg;
 261
 262        curr_gw_orig = batadv_gw_get_selected_orig(bat_priv);
 263        if (!curr_gw_orig)
 264                goto deselect;
 265
 266        router_gw = batadv_orig_node_get_router(curr_gw_orig);
 267        if (!router_gw)
 268                goto deselect;
 269
 270        /* this node already is the gateway */
 271        if (curr_gw_orig == orig_node)
 272                goto out;
 273
 274        router_orig = batadv_orig_node_get_router(orig_node);
 275        if (!router_orig)
 276                goto out;
 277
 278        gw_tq_avg = router_gw->tq_avg;
 279        orig_tq_avg = router_orig->tq_avg;
 280
 281        /* the TQ value has to be better */
 282        if (orig_tq_avg < gw_tq_avg)
 283                goto out;
 284
 285        /* if the routing class is greater than 3 the value tells us how much
 286         * greater the TQ value of the new gateway must be
 287         */
 288        if ((atomic_read(&bat_priv->gw_sel_class) > 3) &&
 289            (orig_tq_avg - gw_tq_avg < atomic_read(&bat_priv->gw_sel_class)))
 290                goto out;
 291
 292        batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 293                   "Restarting gateway selection: better gateway found (tq curr: %i, tq new: %i)\n",
 294                   gw_tq_avg, orig_tq_avg);
 295
 296deselect:
 297        batadv_gw_deselect(bat_priv);
 298out:
 299        if (curr_gw_orig)
 300                batadv_orig_node_free_ref(curr_gw_orig);
 301        if (router_gw)
 302                batadv_neigh_node_free_ref(router_gw);
 303        if (router_orig)
 304                batadv_neigh_node_free_ref(router_orig);
 305
 306        return;
 307}
 308
 309static void batadv_gw_node_add(struct batadv_priv *bat_priv,
 310                               struct batadv_orig_node *orig_node,
 311                               uint8_t new_gwflags)
 312{
 313        struct batadv_gw_node *gw_node;
 314        int down, up;
 315
 316        gw_node = kzalloc(sizeof(*gw_node), GFP_ATOMIC);
 317        if (!gw_node)
 318                return;
 319
 320        INIT_HLIST_NODE(&gw_node->list);
 321        gw_node->orig_node = orig_node;
 322        atomic_set(&gw_node->refcount, 1);
 323
 324        spin_lock_bh(&bat_priv->gw_list_lock);
 325        hlist_add_head_rcu(&gw_node->list, &bat_priv->gw_list);
 326        spin_unlock_bh(&bat_priv->gw_list_lock);
 327
 328        batadv_gw_bandwidth_to_kbit(new_gwflags, &down, &up);
 329        batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 330                   "Found new gateway %pM -> gw_class: %i - %i%s/%i%s\n",
 331                   orig_node->orig, new_gwflags,
 332                   (down > 2048 ? down / 1024 : down),
 333                   (down > 2048 ? "MBit" : "KBit"),
 334                   (up > 2048 ? up / 1024 : up),
 335                   (up > 2048 ? "MBit" : "KBit"));
 336}
 337
 338void batadv_gw_node_update(struct batadv_priv *bat_priv,
 339                           struct batadv_orig_node *orig_node,
 340                           uint8_t new_gwflags)
 341{
 342        struct hlist_node *node;
 343        struct batadv_gw_node *gw_node, *curr_gw;
 344
 345        /* Note: We don't need a NULL check here, since curr_gw never gets
 346         * dereferenced. If curr_gw is NULL we also should not exit as we may
 347         * have this gateway in our list (duplication check!) even though we
 348         * have no currently selected gateway.
 349         */
 350        curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
 351
 352        rcu_read_lock();
 353        hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
 354                if (gw_node->orig_node != orig_node)
 355                        continue;
 356
 357                batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 358                           "Gateway class of originator %pM changed from %i to %i\n",
 359                           orig_node->orig, gw_node->orig_node->gw_flags,
 360                           new_gwflags);
 361
 362                gw_node->deleted = 0;
 363
 364                if (new_gwflags == BATADV_NO_FLAGS) {
 365                        gw_node->deleted = jiffies;
 366                        batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 367                                   "Gateway %pM removed from gateway list\n",
 368                                   orig_node->orig);
 369
 370                        if (gw_node == curr_gw)
 371                                goto deselect;
 372                }
 373
 374                goto unlock;
 375        }
 376
 377        if (new_gwflags == BATADV_NO_FLAGS)
 378                goto unlock;
 379
 380        batadv_gw_node_add(bat_priv, orig_node, new_gwflags);
 381        goto unlock;
 382
 383deselect:
 384        batadv_gw_deselect(bat_priv);
 385unlock:
 386        rcu_read_unlock();
 387
 388        if (curr_gw)
 389                batadv_gw_node_free_ref(curr_gw);
 390}
 391
 392void batadv_gw_node_delete(struct batadv_priv *bat_priv,
 393                           struct batadv_orig_node *orig_node)
 394{
 395        batadv_gw_node_update(bat_priv, orig_node, 0);
 396}
 397
 398void batadv_gw_node_purge(struct batadv_priv *bat_priv)
 399{
 400        struct batadv_gw_node *gw_node, *curr_gw;
 401        struct hlist_node *node, *node_tmp;
 402        unsigned long timeout = msecs_to_jiffies(2 * BATADV_PURGE_TIMEOUT);
 403        int do_deselect = 0;
 404
 405        curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
 406
 407        spin_lock_bh(&bat_priv->gw_list_lock);
 408
 409        hlist_for_each_entry_safe(gw_node, node, node_tmp,
 410                                  &bat_priv->gw_list, list) {
 411                if (((!gw_node->deleted) ||
 412                     (time_before(jiffies, gw_node->deleted + timeout))) &&
 413                    atomic_read(&bat_priv->mesh_state) == BATADV_MESH_ACTIVE)
 414                        continue;
 415
 416                if (curr_gw == gw_node)
 417                        do_deselect = 1;
 418
 419                hlist_del_rcu(&gw_node->list);
 420                batadv_gw_node_free_ref(gw_node);
 421        }
 422
 423        spin_unlock_bh(&bat_priv->gw_list_lock);
 424
 425        /* gw_deselect() needs to acquire the gw_list_lock */
 426        if (do_deselect)
 427                batadv_gw_deselect(bat_priv);
 428
 429        if (curr_gw)
 430                batadv_gw_node_free_ref(curr_gw);
 431}
 432
 433/* fails if orig_node has no router */
 434static int batadv_write_buffer_text(struct batadv_priv *bat_priv,
 435                                    struct seq_file *seq,
 436                                    const struct batadv_gw_node *gw_node)
 437{
 438        struct batadv_gw_node *curr_gw;
 439        struct batadv_neigh_node *router;
 440        int down, up, ret = -1;
 441
 442        batadv_gw_bandwidth_to_kbit(gw_node->orig_node->gw_flags, &down, &up);
 443
 444        router = batadv_orig_node_get_router(gw_node->orig_node);
 445        if (!router)
 446                goto out;
 447
 448        curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
 449
 450        ret = seq_printf(seq, "%s %pM (%3i) %pM [%10s]: %3i - %i%s/%i%s\n",
 451                         (curr_gw == gw_node ? "=>" : "  "),
 452                         gw_node->orig_node->orig,
 453                         router->tq_avg, router->addr,
 454                         router->if_incoming->net_dev->name,
 455                         gw_node->orig_node->gw_flags,
 456                         (down > 2048 ? down / 1024 : down),
 457                         (down > 2048 ? "MBit" : "KBit"),
 458                         (up > 2048 ? up / 1024 : up),
 459                         (up > 2048 ? "MBit" : "KBit"));
 460
 461        batadv_neigh_node_free_ref(router);
 462        if (curr_gw)
 463                batadv_gw_node_free_ref(curr_gw);
 464out:
 465        return ret;
 466}
 467
 468int batadv_gw_client_seq_print_text(struct seq_file *seq, void *offset)
 469{
 470        struct net_device *net_dev = (struct net_device *)seq->private;
 471        struct batadv_priv *bat_priv = netdev_priv(net_dev);
 472        struct batadv_hard_iface *primary_if;
 473        struct batadv_gw_node *gw_node;
 474        struct hlist_node *node;
 475        int gw_count = 0, ret = 0;
 476
 477        primary_if = batadv_primary_if_get_selected(bat_priv);
 478        if (!primary_if) {
 479                ret = seq_printf(seq,
 480                                 "BATMAN mesh %s disabled - please specify interfaces to enable it\n",
 481                                 net_dev->name);
 482                goto out;
 483        }
 484
 485        if (primary_if->if_status != BATADV_IF_ACTIVE) {
 486                ret = seq_printf(seq,
 487                                 "BATMAN mesh %s disabled - primary interface not active\n",
 488                                 net_dev->name);
 489                goto out;
 490        }
 491
 492        seq_printf(seq,
 493                   "      %-12s (%s/%i) %17s [%10s]: gw_class ... [B.A.T.M.A.N. adv %s, MainIF/MAC: %s/%pM (%s)]\n",
 494                   "Gateway", "#", BATADV_TQ_MAX_VALUE, "Nexthop", "outgoingIF",
 495                   BATADV_SOURCE_VERSION, primary_if->net_dev->name,
 496                   primary_if->net_dev->dev_addr, net_dev->name);
 497
 498        rcu_read_lock();
 499        hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
 500                if (gw_node->deleted)
 501                        continue;
 502
 503                /* fails if orig_node has no router */
 504                if (batadv_write_buffer_text(bat_priv, seq, gw_node) < 0)
 505                        continue;
 506
 507                gw_count++;
 508        }
 509        rcu_read_unlock();
 510
 511        if (gw_count == 0)
 512                seq_printf(seq, "No gateways in range ...\n");
 513
 514out:
 515        if (primary_if)
 516                batadv_hardif_free_ref(primary_if);
 517        return ret;
 518}
 519
 520static bool batadv_is_type_dhcprequest(struct sk_buff *skb, int header_len)
 521{
 522        int ret = false;
 523        unsigned char *p;
 524        int pkt_len;
 525
 526        if (skb_linearize(skb) < 0)
 527                goto out;
 528
 529        pkt_len = skb_headlen(skb);
 530
 531        if (pkt_len < header_len + BATADV_DHCP_OPTIONS_OFFSET + 1)
 532                goto out;
 533
 534        p = skb->data + header_len + BATADV_DHCP_OPTIONS_OFFSET;
 535        pkt_len -= header_len + BATADV_DHCP_OPTIONS_OFFSET + 1;
 536
 537        /* Access the dhcp option lists. Each entry is made up by:
 538         * - octet 1: option type
 539         * - octet 2: option data len (only if type != 255 and 0)
 540         * - octet 3: option data
 541         */
 542        while (*p != 255 && !ret) {
 543                /* p now points to the first octet: option type */
 544                if (*p == 53) {
 545                        /* type 53 is the message type option.
 546                         * Jump the len octet and go to the data octet
 547                         */
 548                        if (pkt_len < 2)
 549                                goto out;
 550                        p += 2;
 551
 552                        /* check if the message type is what we need */
 553                        if (*p == BATADV_DHCP_REQUEST)
 554                                ret = true;
 555                        break;
 556                } else if (*p == 0) {
 557                        /* option type 0 (padding), just go forward */
 558                        if (pkt_len < 1)
 559                                goto out;
 560                        pkt_len--;
 561                        p++;
 562                } else {
 563                        /* This is any other option. So we get the length... */
 564                        if (pkt_len < 1)
 565                                goto out;
 566                        pkt_len--;
 567                        p++;
 568
 569                        /* ...and then we jump over the data */
 570                        if (pkt_len < 1 + (*p))
 571                                goto out;
 572                        pkt_len -= 1 + (*p);
 573                        p += 1 + (*p);
 574                }
 575        }
 576out:
 577        return ret;
 578}
 579
 580bool batadv_gw_is_dhcp_target(struct sk_buff *skb, unsigned int *header_len)
 581{
 582        struct ethhdr *ethhdr;
 583        struct iphdr *iphdr;
 584        struct ipv6hdr *ipv6hdr;
 585        struct udphdr *udphdr;
 586
 587        /* check for ethernet header */
 588        if (!pskb_may_pull(skb, *header_len + ETH_HLEN))
 589                return false;
 590        ethhdr = (struct ethhdr *)skb->data;
 591        *header_len += ETH_HLEN;
 592
 593        /* check for initial vlan header */
 594        if (ntohs(ethhdr->h_proto) == ETH_P_8021Q) {
 595                if (!pskb_may_pull(skb, *header_len + VLAN_HLEN))
 596                        return false;
 597                ethhdr = (struct ethhdr *)(skb->data + VLAN_HLEN);
 598                *header_len += VLAN_HLEN;
 599        }
 600
 601        /* check for ip header */
 602        switch (ntohs(ethhdr->h_proto)) {
 603        case ETH_P_IP:
 604                if (!pskb_may_pull(skb, *header_len + sizeof(*iphdr)))
 605                        return false;
 606                iphdr = (struct iphdr *)(skb->data + *header_len);
 607                *header_len += iphdr->ihl * 4;
 608
 609                /* check for udp header */
 610                if (iphdr->protocol != IPPROTO_UDP)
 611                        return false;
 612
 613                break;
 614        case ETH_P_IPV6:
 615                if (!pskb_may_pull(skb, *header_len + sizeof(*ipv6hdr)))
 616                        return false;
 617                ipv6hdr = (struct ipv6hdr *)(skb->data + *header_len);
 618                *header_len += sizeof(*ipv6hdr);
 619
 620                /* check for udp header */
 621                if (ipv6hdr->nexthdr != IPPROTO_UDP)
 622                        return false;
 623
 624                break;
 625        default:
 626                return false;
 627        }
 628
 629        if (!pskb_may_pull(skb, *header_len + sizeof(*udphdr)))
 630                return false;
 631        udphdr = (struct udphdr *)(skb->data + *header_len);
 632        *header_len += sizeof(*udphdr);
 633
 634        /* check for bootp port */
 635        if ((ntohs(ethhdr->h_proto) == ETH_P_IP) &&
 636            (ntohs(udphdr->dest) != 67))
 637                return false;
 638
 639        if ((ntohs(ethhdr->h_proto) == ETH_P_IPV6) &&
 640            (ntohs(udphdr->dest) != 547))
 641                return false;
 642
 643        return true;
 644}
 645
 646bool batadv_gw_out_of_range(struct batadv_priv *bat_priv,
 647                            struct sk_buff *skb, struct ethhdr *ethhdr)
 648{
 649        struct batadv_neigh_node *neigh_curr = NULL, *neigh_old = NULL;
 650        struct batadv_orig_node *orig_dst_node = NULL;
 651        struct batadv_gw_node *curr_gw = NULL;
 652        bool ret, out_of_range = false;
 653        unsigned int header_len = 0;
 654        uint8_t curr_tq_avg;
 655
 656        ret = batadv_gw_is_dhcp_target(skb, &header_len);
 657        if (!ret)
 658                goto out;
 659
 660        orig_dst_node = batadv_transtable_search(bat_priv, ethhdr->h_source,
 661                                                 ethhdr->h_dest);
 662        if (!orig_dst_node)
 663                goto out;
 664
 665        if (!orig_dst_node->gw_flags)
 666                goto out;
 667
 668        ret = batadv_is_type_dhcprequest(skb, header_len);
 669        if (!ret)
 670                goto out;
 671
 672        switch (atomic_read(&bat_priv->gw_mode)) {
 673        case BATADV_GW_MODE_SERVER:
 674                /* If we are a GW then we are our best GW. We can artificially
 675                 * set the tq towards ourself as the maximum value
 676                 */
 677                curr_tq_avg = BATADV_TQ_MAX_VALUE;
 678                break;
 679        case BATADV_GW_MODE_CLIENT:
 680                curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
 681                if (!curr_gw)
 682                        goto out;
 683
 684                /* packet is going to our gateway */
 685                if (curr_gw->orig_node == orig_dst_node)
 686                        goto out;
 687
 688                /* If the dhcp packet has been sent to a different gw,
 689                 * we have to evaluate whether the old gw is still
 690                 * reliable enough
 691                 */
 692                neigh_curr = batadv_find_router(bat_priv, curr_gw->orig_node,
 693                                                NULL);
 694                if (!neigh_curr)
 695                        goto out;
 696
 697                curr_tq_avg = neigh_curr->tq_avg;
 698                break;
 699        case BATADV_GW_MODE_OFF:
 700        default:
 701                goto out;
 702        }
 703
 704        neigh_old = batadv_find_router(bat_priv, orig_dst_node, NULL);
 705        if (!neigh_old)
 706                goto out;
 707
 708        if (curr_tq_avg - neigh_old->tq_avg > BATADV_GW_THRESHOLD)
 709                out_of_range = true;
 710
 711out:
 712        if (orig_dst_node)
 713                batadv_orig_node_free_ref(orig_dst_node);
 714        if (curr_gw)
 715                batadv_gw_node_free_ref(curr_gw);
 716        if (neigh_old)
 717                batadv_neigh_node_free_ref(neigh_old);
 718        if (neigh_curr)
 719                batadv_neigh_node_free_ref(neigh_curr);
 720        return out_of_range;
 721}
 722
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.