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_ref(struct gw_node *gw_node)
  33 {
  34         if (atomic_dec_and_test(&gw_node->refcount))
  35                 kfree_rcu(gw_node, rcu);
  36 }
  37
  38 static struct gw_node *gw_get_selected_gw_node(struct bat_priv *bat_priv)
  39 {
  40         struct gw_node *gw_node;
  41
  42         rcu_read_lock();
  43         gw_node = rcu_dereference(bat_priv->curr_gw);
  44         if (!gw_node)
  45                 goto out;
  46
  47         if (!atomic_inc_not_zero(&gw_node->refcount))
  48                 gw_node = NULL;
  49
  50 out:
  51         rcu_read_unlock();
  52         return gw_node;
  53 }
  54
  55 struct orig_node *gw_get_selected_orig(struct bat_priv *bat_priv)
  56 {
  57         struct gw_node *gw_node;
  58         struct orig_node *orig_node = NULL;
  59
  60         gw_node = gw_get_selected_gw_node(bat_priv);
  61         if (!gw_node)
  62                 goto out;
  63
  64         rcu_read_lock();
  65         orig_node = gw_node->orig_node;
  66         if (!orig_node)
  67                 goto unlock;
  68
  69         if (!atomic_inc_not_zero(&orig_node->refcount))
  70                 orig_node = NULL;
  71
  72 unlock:
  73         rcu_read_unlock();
  74 out:
  75         if (gw_node)
  76                 gw_node_free_ref(gw_node);
  77         return orig_node;
  78 }
  79
  80 static void gw_select(struct bat_priv *bat_priv, struct gw_node *new_gw_node)
  81 {
  82         struct gw_node *curr_gw_node;
  83
  84         spin_lock_bh(&bat_priv->gw_list_lock);
  85
  86         if (new_gw_node && !atomic_inc_not_zero(&new_gw_node->refcount))
  87                 new_gw_node = NULL;
  88
  89         curr_gw_node = bat_priv->curr_gw;
  90         rcu_assign_pointer(bat_priv->curr_gw, new_gw_node);
  91
  92         if (curr_gw_node)
  93                 gw_node_free_ref(curr_gw_node);
  94
  95         spin_unlock_bh(&bat_priv->gw_list_lock);
  96 }
  97
  98 void gw_deselect(struct bat_priv *bat_priv)
  99 {
 100         gw_select(bat_priv, NULL);
 101 }
 102
 103 void gw_election(struct bat_priv *bat_priv)
 104 {
 105         struct hlist_node *node;
 106         struct gw_node *gw_node, *curr_gw = NULL, *curr_gw_tmp = NULL;
 107         struct neigh_node *router;
 108         uint8_t max_tq = 0;
 109         uint32_t max_gw_factor = 0, tmp_gw_factor = 0;
 110         int down, up;
 111
 112         /**
 113          * The batman daemon checks here if we already passed a full originator
 114          * cycle in order to make sure we don't choose the first gateway we
 115          * hear about. This check is based on the daemon's uptime which we
 116          * don't have.
 117          **/
 118         if (atomic_read(&bat_priv->gw_mode) != GW_MODE_CLIENT)
 119                 return;
 120
 121         curr_gw = gw_get_selected_gw_node(bat_priv);
 122         if (curr_gw)
 123                 goto out;
 124
 125         rcu_read_lock();
 126         if (hlist_empty(&bat_priv->gw_list)) {
 127                 bat_dbg(DBG_BATMAN, bat_priv,
 128                         "Removing selected gateway - "
 129                         "no gateway in range\n");
 130                 gw_deselect(bat_priv);
 131                 goto unlock;
 132         }
 133
 134         hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
 135                 if (gw_node->deleted)
 136                         continue;
 137
 138                 router = orig_node_get_router(gw_node->orig_node);
 139                 if (!router)
 140                         continue;
 141
 142                 switch (atomic_read(&bat_priv->gw_sel_class)) {
 143                 case 1: /* fast connection */
 144                         gw_bandwidth_to_kbit(gw_node->orig_node->gw_flags,
 145                                              &down, &up);
 146
 147                         tmp_gw_factor = (router->tq_avg * router->tq_avg *
 148                                          down * 100 * 100) /
 149                                          (TQ_LOCAL_WINDOW_SIZE *
 150                                          TQ_LOCAL_WINDOW_SIZE * 64);
 151
 152                         if ((tmp_gw_factor > max_gw_factor) ||
 153                             ((tmp_gw_factor == max_gw_factor) &&
 154                              (router->tq_avg > max_tq)))
 155                                 curr_gw_tmp = gw_node;
 156                         break;
 157
 158                 default: /**
 159                           * 2:  stable connection (use best statistic)
 160                           * 3:  fast-switch (use best statistic but change as
 161                           *     soon as a better gateway appears)
 162                           * XX: late-switch (use best statistic but change as
 163                           *     soon as a better gateway appears which has
 164                           *     $routing_class more tq points)
 165                           **/
 166                         if (router->tq_avg > max_tq)
 167                                 curr_gw_tmp = gw_node;
 168                         break;
 169                 }
 170
 171                 if (router->tq_avg > max_tq)
 172                         max_tq = router->tq_avg;
 173
 174                 if (tmp_gw_factor > max_gw_factor)
 175                         max_gw_factor = tmp_gw_factor;
 176
 177                 neigh_node_free_ref(router);
 178         }
 179
 180         if (curr_gw != curr_gw_tmp) {
 181                 router = orig_node_get_router(curr_gw_tmp->orig_node);
 182                 if (!router)
 183                         goto unlock;
 184
 185                 if ((curr_gw) && (!curr_gw_tmp))
 186                         bat_dbg(DBG_BATMAN, bat_priv,
 187                                 "Removing selected gateway - "
 188                                 "no gateway in range\n");
 189                 else if ((!curr_gw) && (curr_gw_tmp))
 190                         bat_dbg(DBG_BATMAN, bat_priv,
 191                                 "Adding route to gateway %pM "
 192                                 "(gw_flags: %i, tq: %i)\n",
 193                                 curr_gw_tmp->orig_node->orig,
 194                                 curr_gw_tmp->orig_node->gw_flags,
 195                                 router->tq_avg);
 196                 else
 197                         bat_dbg(DBG_BATMAN, bat_priv,
 198                                 "Changing route to gateway %pM "
 199                                 "(gw_flags: %i, tq: %i)\n",
 200                                 curr_gw_tmp->orig_node->orig,
 201                                 curr_gw_tmp->orig_node->gw_flags,
 202                                 router->tq_avg);
 203
 204                 neigh_node_free_ref(router);
 205                 gw_select(bat_priv, curr_gw_tmp);
 206         }
 207
 208 unlock:
 209         rcu_read_unlock();
 210 out:
 211         if (curr_gw)
 212                 gw_node_free_ref(curr_gw);
 213 }
 214
 215 void gw_check_election(struct bat_priv *bat_priv, struct orig_node *orig_node)
 216 {
 217         struct orig_node *curr_gw_orig;
 218         struct neigh_node *router_gw = NULL, *router_orig = NULL;
 219         uint8_t gw_tq_avg, orig_tq_avg;
 220
 221         curr_gw_orig = gw_get_selected_orig(bat_priv);
 222         if (!curr_gw_orig)
 223                 goto deselect;
 224
 225         router_gw = orig_node_get_router(curr_gw_orig);
 226         if (!router_gw)
 227                 goto deselect;
 228
 229         /* this node already is the gateway */
 230         if (curr_gw_orig == orig_node)
 231                 goto out;
 232
 233         router_orig = orig_node_get_router(orig_node);
 234         if (!router_orig)
 235                 goto out;
 236
 237         gw_tq_avg = router_gw->tq_avg;
 238         orig_tq_avg = router_orig->tq_avg;
 239
 240         /* the TQ value has to be better */
 241         if (orig_tq_avg < gw_tq_avg)
 242                 goto out;
 243
 244         /**
 245          * if the routing class is greater than 3 the value tells us how much
 246          * greater the TQ value of the new gateway must be
 247          **/
 248         if ((atomic_read(&bat_priv->gw_sel_class) > 3) &&
 249             (orig_tq_avg - gw_tq_avg < atomic_read(&bat_priv->gw_sel_class)))
 250                 goto out;
 251
 252         bat_dbg(DBG_BATMAN, bat_priv,
 253                 "Restarting gateway selection: better gateway found (tq curr: "
 254                 "%i, tq new: %i)\n",
 255                 gw_tq_avg, orig_tq_avg);
 256
 257 deselect:
 258         gw_deselect(bat_priv);
 259 out:
 260         if (curr_gw_orig)
 261                 orig_node_free_ref(curr_gw_orig);
 262         if (router_gw)
 263                 neigh_node_free_ref(router_gw);
 264         if (router_orig)
 265                 neigh_node_free_ref(router_orig);
 266
 267         return;
 268 }
 269
 270 static void gw_node_add(struct bat_priv *bat_priv,
 271                         struct orig_node *orig_node, uint8_t new_gwflags)
 272 {
 273         struct gw_node *gw_node;
 274         int down, up;
 275
 276         gw_node = kzalloc(sizeof(*gw_node), GFP_ATOMIC);
 277         if (!gw_node)
 278                 return;
 279
 280         INIT_HLIST_NODE(&gw_node->list);
 281         gw_node->orig_node = orig_node;
 282         atomic_set(&gw_node->refcount, 1);
 283
 284         spin_lock_bh(&bat_priv->gw_list_lock);
 285         hlist_add_head_rcu(&gw_node->list, &bat_priv->gw_list);
 286         spin_unlock_bh(&bat_priv->gw_list_lock);
 287
 288         gw_bandwidth_to_kbit(new_gwflags, &down, &up);
 289         bat_dbg(DBG_BATMAN, bat_priv,
 290                 "Found new gateway %pM -> gw_class: %i - %i%s/%i%s\n",
 291                 orig_node->orig, new_gwflags,
 292                 (down > 2048 ? down / 1024 : down),
 293                 (down > 2048 ? "MBit" : "KBit"),
 294                 (up > 2048 ? up / 1024 : up),
 295                 (up > 2048 ? "MBit" : "KBit"));
 296 }
 297
 298 void gw_node_update(struct bat_priv *bat_priv,
 299                     struct orig_node *orig_node, uint8_t new_gwflags)
 300 {
 301         struct hlist_node *node;
 302         struct gw_node *gw_node, *curr_gw;
 303
 304         /**
 305          * Note: We don't need a NULL check here, since curr_gw never gets
 306          * dereferenced. If curr_gw is NULL we also should not exit as we may
 307          * have this gateway in our list (duplication check!) even though we
 308          * have no currently selected gateway.
 309          */
 310         curr_gw = gw_get_selected_gw_node(bat_priv);
 311
 312         rcu_read_lock();
 313         hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
 314                 if (gw_node->orig_node != orig_node)
 315                         continue;
 316
 317                 bat_dbg(DBG_BATMAN, bat_priv,
 318                         "Gateway class of originator %pM changed from "
 319                         "%i to %i\n",
 320                         orig_node->orig, gw_node->orig_node->gw_flags,
 321                         new_gwflags);
 322
 323                 gw_node->deleted = 0;
 324
 325                 if (new_gwflags == 0) {
 326                         gw_node->deleted = jiffies;
 327                         bat_dbg(DBG_BATMAN, bat_priv,
 328                                 "Gateway %pM removed from gateway list\n",
 329                                 orig_node->orig);
 330
 331                         if (gw_node == curr_gw)
 332                                 goto deselect;
 333                 }
 334
 335                 goto unlock;
 336         }
 337
 338         if (new_gwflags == 0)
 339                 goto unlock;
 340
 341         gw_node_add(bat_priv, orig_node, new_gwflags);
 342         goto unlock;
 343
 344 deselect:
 345         gw_deselect(bat_priv);
 346 unlock:
 347         rcu_read_unlock();
 348
 349         if (curr_gw)
 350                 gw_node_free_ref(curr_gw);
 351 }
 352
 353 void gw_node_delete(struct bat_priv *bat_priv, struct orig_node *orig_node)
 354 {
 355         return gw_node_update(bat_priv, orig_node, 0);
 356 }
 357
 358 void gw_node_purge(struct bat_priv *bat_priv)
 359 {
 360         struct gw_node *gw_node, *curr_gw;
 361         struct hlist_node *node, *node_tmp;
 362         unsigned long timeout = 2 * PURGE_TIMEOUT * HZ;
 363         char do_deselect = 0;
 364
 365         curr_gw = gw_get_selected_gw_node(bat_priv);
 366
 367         spin_lock_bh(&bat_priv->gw_list_lock);
 368
 369         hlist_for_each_entry_safe(gw_node, node, node_tmp,
 370                                   &bat_priv->gw_list, list) {
 371                 if (((!gw_node->deleted) ||
 372                      (time_before(jiffies, gw_node->deleted + timeout))) &&
 373                     atomic_read(&bat_priv->mesh_state) == MESH_ACTIVE)
 374                         continue;
 375
 376                 if (curr_gw == gw_node)
 377                         do_deselect = 1;
 378
 379                 hlist_del_rcu(&gw_node->list);
 380                 gw_node_free_ref(gw_node);
 381         }
 382
 383         spin_unlock_bh(&bat_priv->gw_list_lock);
 384
 385         /* gw_deselect() needs to acquire the gw_list_lock */
 386         if (do_deselect)
 387                 gw_deselect(bat_priv);
 388
 389         if (curr_gw)
 390                 gw_node_free_ref(curr_gw);
 391 }
 392
 393 /**
 394  * fails if orig_node has no router
 395  */
 396 static int _write_buffer_text(struct bat_priv *bat_priv, struct seq_file *seq,
 397                               const struct gw_node *gw_node)
 398 {
 399         struct gw_node *curr_gw;
 400         struct neigh_node *router;
 401         int down, up, ret = -1;
 402
 403         gw_bandwidth_to_kbit(gw_node->orig_node->gw_flags, &down, &up);
 404
 405         router = orig_node_get_router(gw_node->orig_node);
 406         if (!router)
 407                 goto out;
 408
 409         curr_gw = gw_get_selected_gw_node(bat_priv);
 410
 411         ret = seq_printf(seq, "%s %pM (%3i) %pM [%10s]: %3i - %i%s/%i%s\n",
 412                          (curr_gw == gw_node ? "=>" : "  "),
 413                          gw_node->orig_node->orig,
 414                          router->tq_avg, router->addr,
 415                          router->if_incoming->net_dev->name,
 416                          gw_node->orig_node->gw_flags,
 417                          (down > 2048 ? down / 1024 : down),
 418                          (down > 2048 ? "MBit" : "KBit"),
 419                          (up > 2048 ? up / 1024 : up),
 420                          (up > 2048 ? "MBit" : "KBit"));
 421
 422         neigh_node_free_ref(router);
 423         if (curr_gw)
 424                 gw_node_free_ref(curr_gw);
 425 out:
 426         return ret;
 427 }
 428
 429 int gw_client_seq_print_text(struct seq_file *seq, void *offset)
 430 {
 431         struct net_device *net_dev = (struct net_device *)seq->private;
 432         struct bat_priv *bat_priv = netdev_priv(net_dev);
 433         struct hard_iface *primary_if;
 434         struct gw_node *gw_node;
 435         struct hlist_node *node;
 436         int gw_count = 0, ret = 0;
 437
 438         primary_if = primary_if_get_selected(bat_priv);
 439         if (!primary_if) {
 440                 ret = seq_printf(seq, "BATMAN mesh %s disabled - please "
 441                                  "specify interfaces to enable it\n",
 442                                  net_dev->name);
 443                 goto out;
 444         }
 445
 446         if (primary_if->if_status != IF_ACTIVE) {
 447                 ret = seq_printf(seq, "BATMAN mesh %s disabled - "
 448                                  "primary interface not active\n",
 449                                  net_dev->name);
 450                 goto out;
 451         }
 452
 453         seq_printf(seq, "      %-12s (%s/%i) %17s [%10s]: gw_class ... "
 454                    "[B.A.T.M.A.N. adv %s%s, MainIF/MAC: %s/%pM (%s)]\n",
 455                    "Gateway", "#", TQ_MAX_VALUE, "Nexthop",
 456                    "outgoingIF", SOURCE_VERSION, REVISION_VERSION_STR,
 457                    primary_if->net_dev->name,
 458                    primary_if->net_dev->dev_addr, net_dev->name);
 459
 460         rcu_read_lock();
 461         hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
 462                 if (gw_node->deleted)
 463                         continue;
 464
 465                 /* fails if orig_node has no router */
 466                 if (_write_buffer_text(bat_priv, seq, gw_node) < 0)
 467                         continue;
 468
 469                 gw_count++;
 470         }
 471         rcu_read_unlock();
 472
 473         if (gw_count == 0)
 474                 seq_printf(seq, "No gateways in range ...\n");
 475
 476 out:
 477         if (primary_if)
 478                 hardif_free_ref(primary_if);
 479         return ret;
 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(*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(*ipv6hdr)))
 523                         return 0;
 524                 ipv6hdr = (struct ipv6hdr *)(skb->data + header_len);
 525                 header_len += sizeof(*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(*udphdr)))
 537                 return 0;
 538         udphdr = (struct udphdr *)(skb->data + header_len);
 539         header_len += sizeof(*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 }