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 struct orig_node *gw_get_selected(struct bat_priv *bat_priv)
  47 {
  48         struct gw_node *curr_gateway_tmp;
  49         struct orig_node *orig_node = NULL;
  50
  51         rcu_read_lock();
  52         curr_gateway_tmp = rcu_dereference(bat_priv->curr_gw);
  53         if (!curr_gateway_tmp)
  54                 goto out;
  55
  56         orig_node = curr_gateway_tmp->orig_node;
  57         if (!orig_node)
  58                 goto out;
  59
  60         if (!atomic_inc_not_zero(&orig_node->refcount))
  61                 orig_node = NULL;
  62
  63 out:
  64         rcu_read_unlock();
  65         return orig_node;
  66 }
  67
  68 void gw_deselect(struct bat_priv *bat_priv)
  69 {
  70         struct gw_node *gw_node;
  71
  72         spin_lock_bh(&bat_priv->gw_list_lock);
  73         gw_node = rcu_dereference(bat_priv->curr_gw);
  74         rcu_assign_pointer(bat_priv->curr_gw, NULL);
  75         spin_unlock_bh(&bat_priv->gw_list_lock);
  76
  77         if (gw_node)
  78                 gw_node_free_ref(gw_node);
  79 }
  80
  81 static void gw_select(struct bat_priv *bat_priv, struct gw_node *new_gw_node)
  82 {
  83         struct gw_node *curr_gw_node;
  84
  85         if (new_gw_node && !atomic_inc_not_zero(&new_gw_node->refcount))
  86                 new_gw_node = NULL;
  87
  88         spin_lock_bh(&bat_priv->gw_list_lock);
  89         curr_gw_node = rcu_dereference(bat_priv->curr_gw);
  90         rcu_assign_pointer(bat_priv->curr_gw, new_gw_node);
  91         spin_unlock_bh(&bat_priv->gw_list_lock);
  92
  93         if (curr_gw_node)
  94                 gw_node_free_ref(curr_gw_node);
  95 }
  96
  97 void gw_election(struct bat_priv *bat_priv)
  98 {
  99         struct hlist_node *node;
 100         struct gw_node *gw_node, *curr_gw, *curr_gw_tmp = NULL;
 101         struct neigh_node *router;
 102         uint8_t max_tq = 0;
 103         uint32_t max_gw_factor = 0, tmp_gw_factor = 0;
 104         int down, up;
 105
 106         /**
 107          * The batman daemon checks here if we already passed a full originator
 108          * cycle in order to make sure we don't choose the first gateway we
 109          * hear about. This check is based on the daemon's uptime which we
 110          * don't have.
 111          **/
 112         if (atomic_read(&bat_priv->gw_mode) != GW_MODE_CLIENT)
 113                 return;
 114
 115         rcu_read_lock();
 116         curr_gw = rcu_dereference(bat_priv->curr_gw);
 117         if (curr_gw) {
 118                 rcu_read_unlock();
 119                 return;
 120         }
 121
 122         if (hlist_empty(&bat_priv->gw_list)) {
 123
 124                 if (curr_gw) {
 125                         rcu_read_unlock();
 126                         bat_dbg(DBG_BATMAN, bat_priv,
 127                                 "Removing selected gateway - "
 128                                 "no gateway in range\n");
 129                         gw_deselect(bat_priv);
 130                 } else
 131                         rcu_read_unlock();
 132
 133                 return;
 134         }
 135
 136         hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
 137                 if (gw_node->deleted)
 138                         continue;
 139
 140                 router = orig_node_get_router(gw_node->orig_node);
 141                 if (!router)
 142                         continue;
 143
 144                 switch (atomic_read(&bat_priv->gw_sel_class)) {
 145                 case 1: /* fast connection */
 146                         gw_bandwidth_to_kbit(gw_node->orig_node->gw_flags,
 147                                              &down, &up);
 148
 149                         tmp_gw_factor = (router->tq_avg * router->tq_avg *
 150                                          down * 100 * 100) /
 151                                          (TQ_LOCAL_WINDOW_SIZE *
 152                                          TQ_LOCAL_WINDOW_SIZE * 64);
 153
 154                         if ((tmp_gw_factor > max_gw_factor) ||
 155                             ((tmp_gw_factor == max_gw_factor) &&
 156                              (router->tq_avg > max_tq)))
 157                                 curr_gw_tmp = gw_node;
 158                         break;
 159
 160                 default: /**
 161                           * 2:  stable connection (use best statistic)
 162                           * 3:  fast-switch (use best statistic but change as
 163                           *     soon as a better gateway appears)
 164                           * XX: late-switch (use best statistic but change as
 165                           *     soon as a better gateway appears which has
 166                           *     $routing_class more tq points)
 167                           **/
 168                         if (router->tq_avg > max_tq)
 169                                 curr_gw_tmp = gw_node;
 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                 neigh_node_free_ref(router);
 180         }
 181
 182         if (curr_gw != curr_gw_tmp) {
 183                 router = orig_node_get_router(curr_gw_tmp->orig_node);
 184                 if (!router)
 185                         goto out;
 186
 187                 if ((curr_gw) && (!curr_gw_tmp))
 188                         bat_dbg(DBG_BATMAN, bat_priv,
 189                                 "Removing selected gateway - "
 190                                 "no gateway in range\n");
 191                 else if ((!curr_gw) && (curr_gw_tmp))
 192                         bat_dbg(DBG_BATMAN, bat_priv,
 193                                 "Adding route to gateway %pM "
 194                                 "(gw_flags: %i, tq: %i)\n",
 195                                 curr_gw_tmp->orig_node->orig,
 196                                 curr_gw_tmp->orig_node->gw_flags,
 197                                 router->tq_avg);
 198                 else
 199                         bat_dbg(DBG_BATMAN, bat_priv,
 200                                 "Changing route to gateway %pM "
 201                                 "(gw_flags: %i, tq: %i)\n",
 202                                 curr_gw_tmp->orig_node->orig,
 203                                 curr_gw_tmp->orig_node->gw_flags,
 204                                 router->tq_avg);
 205
 206                 neigh_node_free_ref(router);
 207                 gw_select(bat_priv, curr_gw_tmp);
 208         }
 209
 210 out:
 211         rcu_read_unlock();
 212 }
 213
 214 void gw_check_election(struct bat_priv *bat_priv, struct orig_node *orig_node)
 215 {
 216         struct orig_node *curr_gw_orig;
 217         struct neigh_node *router_gw = NULL, *router_orig = NULL;
 218         uint8_t gw_tq_avg, orig_tq_avg;
 219
 220         curr_gw_orig = gw_get_selected(bat_priv);
 221         if (!curr_gw_orig)
 222                 goto deselect;
 223
 224         router_gw = orig_node_get_router(curr_gw_orig);
 225         if (!router_gw)
 226                 goto deselect;
 227
 228         /* this node already is the gateway */
 229         if (curr_gw_orig == orig_node)
 230                 goto out;
 231
 232         router_orig = orig_node_get_router(orig_node);
 233         if (!router_orig)
 234                 goto out;
 235
 236         gw_tq_avg = router_gw->tq_avg;
 237         orig_tq_avg = router_orig->tq_avg;
 238
 239         /* the TQ value has to be better */
 240         if (orig_tq_avg < gw_tq_avg)
 241                 goto out;
 242
 243         /**
 244          * if the routing class is greater than 3 the value tells us how much
 245          * greater the TQ value of the new gateway must be
 246          **/
 247         if ((atomic_read(&bat_priv->gw_sel_class) > 3) &&
 248             (orig_tq_avg - gw_tq_avg < atomic_read(&bat_priv->gw_sel_class)))
 249                 goto out;
 250
 251         bat_dbg(DBG_BATMAN, bat_priv,
 252                 "Restarting gateway selection: better gateway found (tq curr: "
 253                 "%i, tq new: %i)\n",
 254                 gw_tq_avg, orig_tq_avg);
 255
 256 deselect:
 257         gw_deselect(bat_priv);
 258 out:
 259         if (curr_gw_orig)
 260                 orig_node_free_ref(curr_gw_orig);
 261         if (router_gw)
 262                 neigh_node_free_ref(router_gw);
 263         if (router_orig)
 264                 neigh_node_free_ref(router_orig);
 265
 266         return;
 267 }
 268
 269 static void gw_node_add(struct bat_priv *bat_priv,
 270                         struct orig_node *orig_node, uint8_t new_gwflags)
 271 {
 272         struct gw_node *gw_node;
 273         int down, up;
 274
 275         gw_node = kmalloc(sizeof(struct gw_node), GFP_ATOMIC);
 276         if (!gw_node)
 277                 return;
 278
 279         memset(gw_node, 0, sizeof(struct gw_node));
 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;
 303
 304         rcu_read_lock();
 305         hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
 306                 if (gw_node->orig_node != orig_node)
 307                         continue;
 308
 309                 bat_dbg(DBG_BATMAN, bat_priv,
 310                         "Gateway class of originator %pM changed from "
 311                         "%i to %i\n",
 312                         orig_node->orig, gw_node->orig_node->gw_flags,
 313                         new_gwflags);
 314
 315                 gw_node->deleted = 0;
 316
 317                 if (new_gwflags == 0) {
 318                         gw_node->deleted = jiffies;
 319                         bat_dbg(DBG_BATMAN, bat_priv,
 320                                 "Gateway %pM removed from gateway list\n",
 321                                 orig_node->orig);
 322
 323                         if (gw_node == rcu_dereference(bat_priv->curr_gw)) {
 324                                 rcu_read_unlock();
 325                                 gw_deselect(bat_priv);
 326                                 return;
 327                         }
 328                 }
 329
 330                 rcu_read_unlock();
 331                 return;
 332         }
 333         rcu_read_unlock();
 334
 335         if (new_gwflags == 0)
 336                 return;
 337
 338         gw_node_add(bat_priv, orig_node, new_gwflags);
 339 }
 340
 341 void gw_node_delete(struct bat_priv *bat_priv, struct orig_node *orig_node)
 342 {
 343         return gw_node_update(bat_priv, orig_node, 0);
 344 }
 345
 346 void gw_node_purge(struct bat_priv *bat_priv)
 347 {
 348         struct gw_node *gw_node;
 349         struct hlist_node *node, *node_tmp;
 350         unsigned long timeout = 2 * PURGE_TIMEOUT * HZ;
 351
 352         spin_lock_bh(&bat_priv->gw_list_lock);
 353
 354         hlist_for_each_entry_safe(gw_node, node, node_tmp,
 355                                   &bat_priv->gw_list, list) {
 356                 if (((!gw_node->deleted) ||
 357                      (time_before(jiffies, gw_node->deleted + timeout))) &&
 358                     atomic_read(&bat_priv->mesh_state) == MESH_ACTIVE)
 359                         continue;
 360
 361                 if (rcu_dereference(bat_priv->curr_gw) == gw_node)
 362                         gw_deselect(bat_priv);
 363
 364                 hlist_del_rcu(&gw_node->list);
 365                 gw_node_free_ref(gw_node);
 366         }
 367
 368
 369         spin_unlock_bh(&bat_priv->gw_list_lock);
 370 }
 371
 372 /**
 373  * fails if orig_node has no router
 374  */
 375 static int _write_buffer_text(struct bat_priv *bat_priv,
 376                               struct seq_file *seq, struct gw_node *gw_node)
 377 {
 378         struct gw_node *curr_gw;
 379         struct neigh_node *router;
 380         int down, up, ret = -1;
 381
 382         gw_bandwidth_to_kbit(gw_node->orig_node->gw_flags, &down, &up);
 383
 384         router = orig_node_get_router(gw_node->orig_node);
 385         if (!router)
 386                 goto out;
 387
 388         rcu_read_lock();
 389         curr_gw = rcu_dereference(bat_priv->curr_gw);
 390
 391         ret = seq_printf(seq, "%s %pM (%3i) %pM [%10s]: %3i - %i%s/%i%s\n",
 392                        (curr_gw == gw_node ? "=>" : "  "),
 393                        gw_node->orig_node->orig,
 394                        router->tq_avg, router->addr,
 395                        router->if_incoming->net_dev->name,
 396                        gw_node->orig_node->gw_flags,
 397                        (down > 2048 ? down / 1024 : down),
 398                        (down > 2048 ? "MBit" : "KBit"),
 399                        (up > 2048 ? up / 1024 : up),
 400                        (up > 2048 ? "MBit" : "KBit"));
 401
 402         rcu_read_unlock();
 403         neigh_node_free_ref(router);
 404 out:
 405         return ret;
 406 }
 407
 408 int gw_client_seq_print_text(struct seq_file *seq, void *offset)
 409 {
 410         struct net_device *net_dev = (struct net_device *)seq->private;
 411         struct bat_priv *bat_priv = netdev_priv(net_dev);
 412         struct gw_node *gw_node;
 413         struct hlist_node *node;
 414         int gw_count = 0;
 415
 416         if (!bat_priv->primary_if) {
 417
 418                 return seq_printf(seq, "BATMAN mesh %s disabled - please "
 419                                   "specify interfaces to enable it\n",
 420                                   net_dev->name);
 421         }
 422
 423         if (bat_priv->primary_if->if_status != IF_ACTIVE) {
 424
 425                 return seq_printf(seq, "BATMAN mesh %s disabled - "
 426                                        "primary interface not active\n",
 427                                        net_dev->name);
 428         }
 429
 430         seq_printf(seq, "      %-12s (%s/%i) %17s [%10s]: gw_class ... "
 431                    "[B.A.T.M.A.N. adv %s%s, MainIF/MAC: %s/%pM (%s)]\n",
 432                    "Gateway", "#", TQ_MAX_VALUE, "Nexthop",
 433                    "outgoingIF", SOURCE_VERSION, REVISION_VERSION_STR,
 434                    bat_priv->primary_if->net_dev->name,
 435                    bat_priv->primary_if->net_dev->dev_addr, net_dev->name);
 436
 437         rcu_read_lock();
 438         hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
 439                 if (gw_node->deleted)
 440                         continue;
 441
 442                 /* fails if orig_node has no router */
 443                 if (_write_buffer_text(bat_priv, seq, gw_node) < 0)
 444                         continue;
 445
 446                 gw_count++;
 447         }
 448         rcu_read_unlock();
 449
 450         if (gw_count == 0)
 451                 seq_printf(seq, "No gateways in range ...\n");
 452
 453         return 0;
 454 }
 455
 456 int gw_is_target(struct bat_priv *bat_priv, struct sk_buff *skb)
 457 {
 458         struct ethhdr *ethhdr;
 459         struct iphdr *iphdr;
 460         struct ipv6hdr *ipv6hdr;
 461         struct udphdr *udphdr;
 462         unsigned int header_len = 0;
 463
 464         if (atomic_read(&bat_priv->gw_mode) == GW_MODE_OFF)
 465                 return 0;
 466
 467         /* check for ethernet header */
 468         if (!pskb_may_pull(skb, header_len + ETH_HLEN))
 469                 return 0;
 470         ethhdr = (struct ethhdr *)skb->data;
 471         header_len += ETH_HLEN;
 472
 473         /* check for initial vlan header */
 474         if (ntohs(ethhdr->h_proto) == ETH_P_8021Q) {
 475                 if (!pskb_may_pull(skb, header_len + VLAN_HLEN))
 476                         return 0;
 477                 ethhdr = (struct ethhdr *)(skb->data + VLAN_HLEN);
 478                 header_len += VLAN_HLEN;
 479         }
 480
 481         /* check for ip header */
 482         switch (ntohs(ethhdr->h_proto)) {
 483         case ETH_P_IP:
 484                 if (!pskb_may_pull(skb, header_len + sizeof(struct iphdr)))
 485                         return 0;
 486                 iphdr = (struct iphdr *)(skb->data + header_len);
 487                 header_len += iphdr->ihl * 4;
 488
 489                 /* check for udp header */
 490                 if (iphdr->protocol != IPPROTO_UDP)
 491                         return 0;
 492
 493                 break;
 494         case ETH_P_IPV6:
 495                 if (!pskb_may_pull(skb, header_len + sizeof(struct ipv6hdr)))
 496                         return 0;
 497                 ipv6hdr = (struct ipv6hdr *)(skb->data + header_len);
 498                 header_len += sizeof(struct ipv6hdr);
 499
 500                 /* check for udp header */
 501                 if (ipv6hdr->nexthdr != IPPROTO_UDP)
 502                         return 0;
 503
 504                 break;
 505         default:
 506                 return 0;
 507         }
 508
 509         if (!pskb_may_pull(skb, header_len + sizeof(struct udphdr)))
 510                 return 0;
 511         udphdr = (struct udphdr *)(skb->data + header_len);
 512         header_len += sizeof(struct udphdr);
 513
 514         /* check for bootp port */
 515         if ((ntohs(ethhdr->h_proto) == ETH_P_IP) &&
 516              (ntohs(udphdr->dest) != 67))
 517                 return 0;
 518
 519         if ((ntohs(ethhdr->h_proto) == ETH_P_IPV6) &&
 520             (ntohs(udphdr->dest) != 547))
 521                 return 0;
 522
 523         if (atomic_read(&bat_priv->gw_mode) == GW_MODE_SERVER)
 524                 return -1;
 525
 526         rcu_read_lock();
 527         if (!rcu_dereference(bat_priv->curr_gw)) {
 528                 rcu_read_unlock();
 529                 return 0;
 530         }
 531         rcu_read_unlock();
 532
 533         return 1;
 534 }