net/batman-adv/gateway_client.c

   1 /*
   2  * Copyright (C) 2009-2011 B.A.T.M.A.N. contributors:
   3  *
   4  * Marek Lindner
   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, write to the Free Software
  17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  18  * 02110-1301, USA
  19  *
  20  */
  21
  22 #include "main.h"
  23 #include "gateway_client.h"
  24 #include "gateway_common.h"
  25 #include "hard-interface.h"
  26 #include "originator.h"
  27 #include <linux/ip.h>
  28 #include <linux/ipv6.h>
  29 #include <linux/udp.h>
  30 #include <linux/if_vlan.h>
  31
  32 static void gw_node_free_rcu(struct rcu_head *rcu)
  33 {
  34         struct gw_node *gw_node;
  35
  36         gw_node = container_of(rcu, struct gw_node, rcu);
  37         kfree(gw_node);
  38 }
  39
  40 static void gw_node_free_ref(struct gw_node *gw_node)
  41 {
  42         if (atomic_dec_and_test(&gw_node->refcount))
  43                 call_rcu(&gw_node->rcu, gw_node_free_rcu);
  44 }
  45
  46 static struct gw_node *gw_get_selected_gw_node(struct bat_priv *bat_priv)
  47 {
  48         struct 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
  58 out:
  59         rcu_read_unlock();
  60         return gw_node;
  61 }
  62
  63 struct orig_node *gw_get_selected_orig(struct bat_priv *bat_priv)
  64 {
  65         struct gw_node *gw_node;
  66         struct orig_node *orig_node = NULL;
  67
  68         gw_node = gw_get_selected_gw_node(bat_priv);
  69         if (!gw_node)
  70                 goto out;
  71
  72         rcu_read_lock();
  73         orig_node = gw_node->orig_node;
  74         if (!orig_node)
  75                 goto unlock;
  76
  77         if (!atomic_inc_not_zero(&orig_node->refcount))
  78                 orig_node = NULL;
  79
  80 unlock:
  81         rcu_read_unlock();
  82 out:
  83         if (gw_node)
  84                 gw_node_free_ref(gw_node);
  85         return orig_node;
  86 }
  87
  88 static void gw_select(struct bat_priv *bat_priv, struct gw_node *new_gw_node)
  89 {
  90         struct gw_node *curr_gw_node;
  91
  92         spin_lock_bh(&bat_priv->gw_list_lock);
  93
  94         if (new_gw_node && !atomic_inc_not_zero(&new_gw_node->refcount))
  95                 new_gw_node = NULL;
  96
  97         curr_gw_node = bat_priv->curr_gw;
  98         rcu_assign_pointer(bat_priv->curr_gw, new_gw_node);
  99
 100         if (curr_gw_node)
 101                 gw_node_free_ref(curr_gw_node);
 102
 103         spin_unlock_bh(&bat_priv->gw_list_lock);
 104 }
 105
 106 void gw_deselect(struct bat_priv *bat_priv)
 107 {
 108         gw_select(bat_priv, NULL);
 109 }
 110
 111 void gw_election(struct bat_priv *bat_priv)
 112 {
 113         struct hlist_node *node;
 114         struct gw_node *gw_node, *curr_gw = NULL, *curr_gw_tmp = NULL;
 115         struct neigh_node *router;
 116         uint8_t max_tq = 0;
 117         uint32_t max_gw_factor = 0, tmp_gw_factor = 0;
 118         int down, up;
 119
 120         /**
 121          * The batman daemon checks here if we already passed a full originator
 122          * cycle in order to make sure we don't choose the first gateway we
 123          * hear about. This check is based on the daemon's uptime which we
 124          * don't have.
 125          **/
 126         if (atomic_read(&bat_priv->gw_mode) != GW_MODE_CLIENT)
 127                 return;
 128
 129         curr_gw = gw_get_selected_gw_node(bat_priv);
 130         if (!curr_gw)
 131                 goto out;
 132
 133         rcu_read_lock();
 134         if (hlist_empty(&bat_priv->gw_list)) {
 135                 bat_dbg(DBG_BATMAN, bat_priv,
 136                         "Removing selected gateway - "
 137                         "no gateway in range\n");
 138                 gw_deselect(bat_priv);
 139                 goto unlock;
 140         }
 141
 142         hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
 143                 if (gw_node->deleted)
 144                         continue;
 145
 146                 router = orig_node_get_router(gw_node->orig_node);
 147                 if (!router)
 148                         continue;
 149
 150                 switch (atomic_read(&bat_priv->gw_sel_class)) {
 151                 case 1: /* fast connection */
 152                         gw_bandwidth_to_kbit(gw_node->orig_node->gw_flags,
 153                                              &down, &up);
 154
 155                         tmp_gw_factor = (router->tq_avg * router->tq_avg *
 156                                          down * 100 * 100) /
 157                                          (TQ_LOCAL_WINDOW_SIZE *
 158                                          TQ_LOCAL_WINDOW_SIZE * 64);
 159
 160                         if ((tmp_gw_factor > max_gw_factor) ||
 161                             ((tmp_gw_factor == max_gw_factor) &&
 162                              (router->tq_avg > max_tq)))
 163                                 curr_gw_tmp = gw_node;
 164                         break;
 165
 166                 default: /**
 167                           * 2:  stable connection (use best statistic)
 168                           * 3:  fast-switch (use best statistic but change as
 169                           *     soon as a better gateway appears)
 170                           * XX: late-switch (use best statistic but change as
 171                           *     soon as a better gateway appears which has
 172                           *     $routing_class more tq points)
 173                           **/
 174                         if (router->tq_avg > max_tq)
 175                                 curr_gw_tmp = gw_node;
 176                         break;
 177                 }
 178
 179                 if (router->tq_avg > max_tq)
 180                         max_tq = router->tq_avg;
 181
 182                 if (tmp_gw_factor > max_gw_factor)
 183                         max_gw_factor = tmp_gw_factor;
 184
 185                 neigh_node_free_ref(router);
 186         }
 187
 188         if (curr_gw != curr_gw_tmp) {
 189                 router = orig_node_get_router(curr_gw_tmp->orig_node);
 190                 if (!router)
 191                         goto unlock;
 192
 193                 if ((curr_gw) && (!curr_gw_tmp))
 194                         bat_dbg(DBG_BATMAN, bat_priv,
 195                                 "Removing selected gateway - "
 196                                 "no gateway in range\n");
 197                 else if ((!curr_gw) && (curr_gw_tmp))
 198                         bat_dbg(DBG_BATMAN, bat_priv,
 199                                 "Adding route to gateway %pM "
 200                                 "(gw_flags: %i, tq: %i)\n",
 201                                 curr_gw_tmp->orig_node->orig,
 202                                 curr_gw_tmp->orig_node->gw_flags,
 203                                 router->tq_avg);
 204                 else
 205                         bat_dbg(DBG_BATMAN, bat_priv,
 206                                 "Changing route to gateway %pM "
 207                                 "(gw_flags: %i, tq: %i)\n",
 208                                 curr_gw_tmp->orig_node->orig,
 209                                 curr_gw_tmp->orig_node->gw_flags,
 210                                 router->tq_avg);
 211
 212                 neigh_node_free_ref(router);
 213                 gw_select(bat_priv, curr_gw_tmp);
 214         }
 215
 216 unlock:
 217         rcu_read_unlock();
 218 out:
 219         if (curr_gw)
 220                 gw_node_free_ref(curr_gw);
 221 }
 222
 223 void gw_check_election(struct bat_priv *bat_priv, struct orig_node *orig_node)
 224 {
 225         struct orig_node *curr_gw_orig;
 226         struct neigh_node *router_gw = NULL, *router_orig = NULL;
 227         uint8_t gw_tq_avg, orig_tq_avg;
 228
 229         curr_gw_orig = gw_get_selected_orig(bat_priv);
 230         if (!curr_gw_orig)
 231                 goto deselect;
 232
 233         router_gw = orig_node_get_router(curr_gw_orig);
 234         if (!router_gw)
 235                 goto deselect;
 236
 237         /* this node already is the gateway */
 238         if (curr_gw_orig == orig_node)
 239                 goto out;
 240
 241         router_orig = orig_node_get_router(orig_node);
 242         if (!router_orig)
 243                 goto out;
 244
 245         gw_tq_avg = router_gw->tq_avg;
 246         orig_tq_avg = router_orig->tq_avg;
 247
 248         /* the TQ value has to be better */
 249         if (orig_tq_avg < gw_tq_avg)
 250                 goto out;
 251
 252         /**
 253          * if the routing class is greater than 3 the value tells us how much
 254          * greater the TQ value of the new gateway must be
 255          **/
 256         if ((atomic_read(&bat_priv->gw_sel_class) > 3) &&
 257             (orig_tq_avg - gw_tq_avg < atomic_read(&bat_priv->gw_sel_class)))
 258                 goto out;
 259
 260         bat_dbg(DBG_BATMAN, bat_priv,
 261                 "Restarting gateway selection: better gateway found (tq curr: "
 262                 "%i, tq new: %i)\n",
 263                 gw_tq_avg, orig_tq_avg);
 264
 265 deselect:
 266         gw_deselect(bat_priv);
 267 out:
 268         if (curr_gw_orig)
 269                 orig_node_free_ref(curr_gw_orig);
 270         if (router_gw)
 271                 neigh_node_free_ref(router_gw);
 272         if (router_orig)
 273                 neigh_node_free_ref(router_orig);
 274
 275         return;
 276 }
 277
 278 static void gw_node_add(struct bat_priv *bat_priv,
 279                         struct orig_node *orig_node, uint8_t new_gwflags)
 280 {
 281         struct gw_node *gw_node;
 282         int down, up;
 283
 284         gw_node = kmalloc(sizeof(struct gw_node), GFP_ATOMIC);
 285         if (!gw_node)
 286                 return;
 287
 288         memset(gw_node, 0, sizeof(struct gw_node));
 289         INIT_HLIST_NODE(&gw_node->list);
 290         gw_node->orig_node = orig_node;
 291         atomic_set(&gw_node->refcount, 1);
 292
 293         spin_lock_bh(&bat_priv->gw_list_lock);
 294         hlist_add_head_rcu(&gw_node->list, &bat_priv->gw_list);
 295         spin_unlock_bh(&bat_priv->gw_list_lock);
 296
 297         gw_bandwidth_to_kbit(new_gwflags, &down, &up);
 298         bat_dbg(DBG_BATMAN, bat_priv,
 299                 "Found new gateway %pM -> gw_class: %i - %i%s/%i%s\n",
 300                 orig_node->orig, new_gwflags,
 301                 (down > 2048 ? down / 1024 : down),
 302                 (down > 2048 ? "MBit" : "KBit"),
 303                 (up > 2048 ? up / 1024 : up),
 304                 (up > 2048 ? "MBit" : "KBit"));
 305 }
 306
 307 void gw_node_update(struct bat_priv *bat_priv,
 308                     struct orig_node *orig_node, uint8_t new_gwflags)
 309 {
 310         struct hlist_node *node;
 311         struct gw_node *gw_node, *curr_gw;
 312
 313         curr_gw = gw_get_selected_gw_node(bat_priv);
 314         if (!curr_gw)
 315                 goto out;
 316
 317         rcu_read_lock();
 318         hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
 319                 if (gw_node->orig_node != orig_node)
 320                         continue;
 321
 322                 bat_dbg(DBG_BATMAN, bat_priv,
 323                         "Gateway class of originator %pM changed from "
 324                         "%i to %i\n",
 325                         orig_node->orig, gw_node->orig_node->gw_flags,
 326                         new_gwflags);
 327
 328                 gw_node->deleted = 0;
 329
 330                 if (new_gwflags == 0) {
 331                         gw_node->deleted = jiffies;
 332                         bat_dbg(DBG_BATMAN, bat_priv,
 333                                 "Gateway %pM removed from gateway list\n",
 334                                 orig_node->orig);
 335
 336                         if (gw_node == curr_gw)
 337                                 goto deselect;
 338                 }
 339
 340                 goto unlock;
 341         }
 342
 343         if (new_gwflags == 0)
 344                 goto unlock;
 345
 346         gw_node_add(bat_priv, orig_node, new_gwflags);
 347         goto unlock;
 348
 349 deselect:
 350         gw_deselect(bat_priv);
 351 unlock:
 352         rcu_read_unlock();
 353 out:
 354         if (curr_gw)
 355                 gw_node_free_ref(curr_gw);
 356 }
 357
 358 void gw_node_delete(struct bat_priv *bat_priv, struct orig_node *orig_node)
 359 {
 360         return gw_node_update(bat_priv, orig_node, 0);
 361 }
 362
 363 void gw_node_purge(struct bat_priv *bat_priv)
 364 {
 365         struct gw_node *gw_node, *curr_gw;
 366         struct hlist_node *node, *node_tmp;
 367         unsigned long timeout = 2 * PURGE_TIMEOUT * HZ;
 368         char do_deselect = 0;
 369
 370         curr_gw = gw_get_selected_gw_node(bat_priv);
 371
 372         spin_lock_bh(&bat_priv->gw_list_lock);
 373
 374         hlist_for_each_entry_safe(gw_node, node, node_tmp,
 375                                   &bat_priv->gw_list, list) {
 376                 if (((!gw_node->deleted) ||
 377                      (time_before(jiffies, gw_node->deleted + timeout))) &&
 378                     atomic_read(&bat_priv->mesh_state) == MESH_ACTIVE)
 379                         continue;
 380
 381                 if (curr_gw == gw_node)
 382                         do_deselect = 1;
 383
 384                 hlist_del_rcu(&gw_node->list);
 385                 gw_node_free_ref(gw_node);
 386         }
 387
 388         spin_unlock_bh(&bat_priv->gw_list_lock);
 389
 390         /* gw_deselect() needs to acquire the gw_list_lock */
 391         if (do_deselect)
 392                 gw_deselect(bat_priv);
 393
 394         if (curr_gw)
 395                 gw_node_free_ref(curr_gw);
 396 }
 397
 398 /**
 399  * fails if orig_node has no router
 400  */
 401 static int _write_buffer_text(struct bat_priv *bat_priv,
 402                               struct seq_file *seq, struct gw_node *gw_node)
 403 {
 404         struct gw_node *curr_gw;
 405         struct neigh_node *router;
 406         int down, up, ret = -1;
 407
 408         gw_bandwidth_to_kbit(gw_node->orig_node->gw_flags, &down, &up);
 409
 410         router = orig_node_get_router(gw_node->orig_node);
 411         if (!router)
 412                 goto out;
 413
 414         curr_gw = gw_get_selected_gw_node(bat_priv);
 415
 416         ret = seq_printf(seq, "%s %pM (%3i) %pM [%10s]: %3i - %i%s/%i%s\n",
 417                          (curr_gw == gw_node ? "=>" : "  "),
 418                          gw_node->orig_node->orig,
 419                          router->tq_avg, router->addr,
 420                          router->if_incoming->net_dev->name,
 421                          gw_node->orig_node->gw_flags,
 422                          (down > 2048 ? down / 1024 : down),
 423                          (down > 2048 ? "MBit" : "KBit"),
 424                          (up > 2048 ? up / 1024 : up),
 425                          (up > 2048 ? "MBit" : "KBit"));
 426
 427         neigh_node_free_ref(router);
 428         if (curr_gw)
 429                 gw_node_free_ref(curr_gw);
 430 out:
 431         return ret;
 432 }
 433
 434 int gw_client_seq_print_text(struct seq_file *seq, void *offset)
 435 {
 436         struct net_device *net_dev = (struct net_device *)seq->private;
 437         struct bat_priv *bat_priv = netdev_priv(net_dev);
 438         struct gw_node *gw_node;
 439         struct hlist_node *node;
 440         int gw_count = 0;
 441
 442         if (!bat_priv->primary_if) {
 443
 444                 return seq_printf(seq, "BATMAN mesh %s disabled - please "
 445                                   "specify interfaces to enable it\n",
 446                                   net_dev->name);
 447         }
 448
 449         if (bat_priv->primary_if->if_status != IF_ACTIVE) {
 450
 451                 return seq_printf(seq, "BATMAN mesh %s disabled - "
 452                                        "primary interface not active\n",
 453                                        net_dev->name);
 454         }
 455
 456         seq_printf(seq, "      %-12s (%s/%i) %17s [%10s]: gw_class ... "
 457                    "[B.A.T.M.A.N. adv %s%s, MainIF/MAC: %s/%pM (%s)]\n",
 458                    "Gateway", "#", TQ_MAX_VALUE, "Nexthop",
 459                    "outgoingIF", SOURCE_VERSION, REVISION_VERSION_STR,
 460                    bat_priv->primary_if->net_dev->name,
 461                    bat_priv->primary_if->net_dev->dev_addr, net_dev->name);
 462
 463         rcu_read_lock();
 464         hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
 465                 if (gw_node->deleted)
 466                         continue;
 467
 468                 /* fails if orig_node has no router */
 469                 if (_write_buffer_text(bat_priv, seq, gw_node) < 0)
 470                         continue;
 471
 472                 gw_count++;
 473         }
 474         rcu_read_unlock();
 475
 476         if (gw_count == 0)
 477                 seq_printf(seq, "No gateways in range ...\n");
 478
 479         return 0;
 480 }
 481
 482 int gw_is_target(struct bat_priv *bat_priv, struct sk_buff *skb)
 483 {
 484         struct ethhdr *ethhdr;
 485         struct iphdr *iphdr;
 486         struct ipv6hdr *ipv6hdr;
 487         struct udphdr *udphdr;
 488         struct gw_node *curr_gw;
 489         unsigned int header_len = 0;
 490
 491         if (atomic_read(&bat_priv->gw_mode) == GW_MODE_OFF)
 492                 return 0;
 493
 494         /* check for ethernet header */
 495         if (!pskb_may_pull(skb, header_len + ETH_HLEN))
 496                 return 0;
 497         ethhdr = (struct ethhdr *)skb->data;
 498         header_len += ETH_HLEN;
 499
 500         /* check for initial vlan header */
 501         if (ntohs(ethhdr->h_proto) == ETH_P_8021Q) {
 502                 if (!pskb_may_pull(skb, header_len + VLAN_HLEN))
 503                         return 0;
 504                 ethhdr = (struct ethhdr *)(skb->data + VLAN_HLEN);
 505                 header_len += VLAN_HLEN;
 506         }
 507
 508         /* check for ip header */
 509         switch (ntohs(ethhdr->h_proto)) {
 510         case ETH_P_IP:
 511                 if (!pskb_may_pull(skb, header_len + sizeof(struct iphdr)))
 512                         return 0;
 513                 iphdr = (struct iphdr *)(skb->data + header_len);
 514                 header_len += iphdr->ihl * 4;
 515
 516                 /* check for udp header */
 517                 if (iphdr->protocol != IPPROTO_UDP)
 518                         return 0;
 519
 520                 break;
 521         case ETH_P_IPV6:
 522                 if (!pskb_may_pull(skb, header_len + sizeof(struct ipv6hdr)))
 523                         return 0;
 524                 ipv6hdr = (struct ipv6hdr *)(skb->data + header_len);
 525                 header_len += sizeof(struct ipv6hdr);
 526
 527                 /* check for udp header */
 528                 if (ipv6hdr->nexthdr != IPPROTO_UDP)
 529                         return 0;
 530
 531                 break;
 532         default:
 533                 return 0;
 534         }
 535
 536         if (!pskb_may_pull(skb, header_len + sizeof(struct udphdr)))
 537                 return 0;
 538         udphdr = (struct udphdr *)(skb->data + header_len);
 539         header_len += sizeof(struct udphdr);
 540
 541         /* check for bootp port */
 542         if ((ntohs(ethhdr->h_proto) == ETH_P_IP) &&
 543              (ntohs(udphdr->dest) != 67))
 544                 return 0;
 545
 546         if ((ntohs(ethhdr->h_proto) == ETH_P_IPV6) &&
 547             (ntohs(udphdr->dest) != 547))
 548                 return 0;
 549
 550         if (atomic_read(&bat_priv->gw_mode) == GW_MODE_SERVER)
 551                 return -1;
 552
 553         curr_gw = gw_get_selected_gw_node(bat_priv);
 554         if (!curr_gw)
 555                 return 0;
 556
 557         if (curr_gw)
 558                 gw_node_free_ref(curr_gw);
 559         return 1;
 560 }